# Patent

## Title
Printhead assembly with communications module

## Abstract

A printhead assembly with a communications module for a wallpaper printing system, the printhead assembly comprising: a casing; a printhead module; a fluid channel member positioned adjacent to the printhead module, the fluid channel member including a plurality of ducts that substantially span the length of the printhead module; a power supply connection port positioned at a distal end of the casing, the power supply port electrically connected to at least one busbar that substantially spans the length of the printhead module; a fluid delivery connection port positioned at a distal end of the casing, the fluid delivery port in fluid communication with the fluid channel member; and, a data connection port positioned at a distal end of the casing, the data port electrically connected to at least one printed circuit board positioned within the casing, the at least one printed circuit board further electrically connected to the printhead module.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. application Ser. No. 10/760,230 filed on Jan. 21, 2004 now U.S. Pat. No. 7,237,888.


FIELD OF THE INVENTION
The invention pertains to printers and more particularly to a printer for wide format and components of the printer. The printer is particularly well suited to print relatively wide rolls of full color web media in a desired length and is well suited to serve as the basis of both retail and franchise operations which pertain to print-on-demand web media.
CO-PENDING APPLICATIONS
Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention simultaneously with the present application:

















10/962413
10/962427
10/962418
10/962511
10/962402
10/962425


10/962428
10/962416
10/962426
10/962409
10/962417
10/962403


10/962399
10/962522
10/962523
10/962410









The disclosures of these co-pending applications are incorporated herein by cross-reference.
CROSS REFERENCE TO RELATED APPLICATIONS
The following patents or patent applications filed by the applicant or assignee of the present invention are hereby incorporated by cross-reference.

















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BACKGROUND OF THE INVENTION
The invention is suitable for a wide range of applications including, but not limited to:

    
    
        wallpaper;
        billboard panels;
        architectural plans;
        advertising and promotional posters; and
        banners and signage.

However, in the interests of brevity, it will be described with particular reference to wallpaper and an associated method of production. It will be appreciated that the on-demand wallpaper printing sytem described herein is purely illustrative and the invention has much broader application.

    
    


Wallpaper
The size of the wallpaper market in the United States, Japan and Europe offers strong opportunities for innovation and competition. The retail wall covering market in the United States in 1997 was USD $1.1 billion and the market in the United States is estimated at over US $1.5 billion today. The wholesale wallpaper market in Japan in 1999 was JPY ¥158.96 billion. The UK wall coverings market was £186m in 2000 and is expected to grow to £197m in 2004.
Wallpapers are a leading form of interior design product for home improvement and for commercial applications such as in offices, hotels and halls. About 70 million rolls of wallpaper are sold each year in the United States through thousands of retail and design stores. In Japan, around 280 million rolls of wallpaper are sold each year.
The wallpaper industry currently operates around an inventory based model where wallpaper is printed in centralized printing plants using large and expensive printing presses. Printed rolls are distributed to a point of sale where wallpaper designs are selected by consumers and purchased subject to availability. Inventory based sales are hindered by the size and content of the inventory.
The present invention seeks to transform the way wallpaper is currently manufactured, distributed and sold. The invention provides for convenient, low cost, high quality products coupled with a dramatically expanded range of designs and widths which may be offered by virtue of the present invention.
Printing Technologies
Many different types of printing have been invented, a large number of which are presently in use. The known forms of print have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.
In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature.
Many different techniques on inkjet printing have been invented. For a survey of the field, reference is made to an article by J Moore, “Non-Impact Printing: Introduction and Historical Perspective”, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).
Ink Jet printers themselves come in many different types. The utilization of a continuous stream of ink in ink jet printing appears to date back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hansell discloses a simple form of continuous stream electro-static ink jet printing.
U.S. Pat. No. 3,596,275 by Sweet also discloses a process of a continuous ink jet printing including the step wherein the ink jet stream is modulated by a high frequency electro-static field so as to cause drop separation. This technique is still utilized by several manufacturers including Elmjet and Scitex (see also U.S. Pat. No. 3,373,437 by Sweet et al)
Piezoelectric inkjet printers are also one form of commonly utilized ink jet printing device. Piezoelectric systems are disclosed by Kyser et. al. in U.S. Pat. No. 3,946,398 (1970) which utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezoelectric crystal, Stemme in U.S. Pat. No. 3747120 (1972) discloses a bend mode of piezoelectric operation, Howkins in U.S. Pat. No. 4,459,601 discloses a piezoelectric push mode actuation of the inkjet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a shear mode type of piezoelectric transducer element.
Recently, thermal inkjet printing has become an extremely popular form of inkjet printing. The ink jet printing techniques include those disclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S. Pat. No. 4,490,728. Both the aforementioned references disclosed inkjet printing techniques that rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard.
As can be seen from the foregoing, many different types of printing technologies are available. Ideally, a printing technology should have a number of desirable attributes. These include inexpensive construction and operation, high speed operation, safe and continuous long term operation etc. Each technology may have its own advantages and disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity of construction operation, durability and consumables.
In the construction of any inkjet printing system, there are a considerable number of important factors which must be traded off against one another especially as large scale printheads are constructed, especially those of a pagewidth type. A number of these factors are outlined in the following paragraphs.
Firstly, inkjet printheads are normally constructed utilizing micro-electromechanical systems (MEMS) techniques. As such, they tend to rely upon standard integrated circuit construction/fabrication techniques of depositing planar layers on a silicon wafer and etching certain portions of the planar layers. Within silicon circuit fabrication technology, certain techniques are more well known than others. For example, the techniques associated with the creation of CMOS circuits are likely to be more readily used than those associated with the creation of exotic circuits including ferroelectrics, galium arsenide etc. Hence, it is desirable, in any MEMS constructions, to utilize well proven semi-conductor fabrication techniques which do not require any “exotic” processes or materials. Of course, a certain degree of trade off will be undertaken in that if the advantages of using the exotic material far out weighs its disadvantages then it may become desirable to utilize the material anyway.
With a large array of ink ejection nozzles, it is desirable to provide for a highly automated form of manufacturing which results in an inexpensive production of multiple printhead devices.
Preferably, the device constructed utilizes a low amount of energy in the ejection of ink. The utilization of a low amount of energy is particularly important when a large pagewidth full color printhead is constructed having a large array of individual print ejection mechanism with each ejection mechanisms, in the worst case, being fired in a rapid sequence. The device would have wide application in traditional areas of inkjet printing as well as areas previously unrelated to inkjet printing. On such area is the production wallpaper.
OBJECTS AND SUMMARY OF THE INVENTION
In a broad form, the present invention seeks to provide, or assist in providing, an alternative to existing wallpaper printing technology and business methods.
The invention can enable or facilitate on-demand printing and delivery of wallpaper in retail or design stores to a customer's required roll length, that is wallpaper width and length.
The invention can also enable or facilitate on-demand access to a range or portfolio of designs, for example for customer sampling and sale.
The invention may provide, or assist in providing, photographic quality wallpaper designs that are not possible using analogue printing techniques.
In a particular form, the invention may also assist to eliminate stock-out, stock-control/ordering and stock obsolesces issues.
The invention may also enable or facilitate significant reductions in customer wallpaper wastage by enabling or facilitating the printing of wallpaper to any length (and a variety of widths) required by the customer, rather that restricting customer purchases to fixed roll sizes of wallpaper.
The invention seeks to enable or facilitate customization and innovation of wallpaper pattern design for individuals or businesses.
In a first broad embodiment, there is provided a printing system for printing a consumer selected print on a media web, the printing system comprising:
at least one media cartridge containing the media web;
a printhead extending at least the width of the media web;
first drive means to drive the media web past the printhead;
at least one processor to receive and process the selected print and to control printing of the selected print, by the printhead, on the media web; and,
second drive means to drive the media web onto a roller to be wound by a winding means.
In particular forms, the printing system further comprises:
a user interface for the consumer to select the selected print, the user interface having touch screen; and or
a barcode scanner for the consumer to select the selected print.
In some embodiments, the at least one media cartridge is reusable, the at least one media cartridge is moved into a printing position by a carousel, the media web includes one or more background patterns or colors.
In some preferred forms, the first drive means is located within the at least one media cartridge, the first drive means is at least one driven roller, the first drive means comprises a driven roller associated with an idler roller, the second drive means is located within a cutter module, the second drive means is at least one driven roller, the second drive means comprises a driven roller associated with an idler roller, the roller is part of a container provided to the consumer, and/or the winding means is a driven support provided in working association with the roller.
In particularly preferred embodiments, the selected print is a wallpaper pattern such that the printing system produces wallpaper.
In a second broad embodiment, there is provided a cabinet for a printing system for printing a consumer selected print on a media web, the cabinet comprising:
a support adapted to hold at least one media cartridge, containing the media web, and to hold a printhead;
at least one guide to direct the media web past the printhead;
a further support adapted to hold at least one ink reservoir in fluid communication with the printhead;
at least one module adapted to hold at least one processor;
a user interface to forward user instructions to the at least one processor;
a drying compartment to dry printed lengths of the media web; and
a receiving stage to receive printed lengths of the media web onto a roller.
In further particular forms of the invention, the at least one guide is a pre-heater, the at least one guide is substantially planar, the further support holds the at least one ink reservoir at a height greater than the height of the printhead, the further support includes at least one ink supply tube harness, each at least one ink reservoir has an ink level monitor, the ink level monitor is in communication with the at least one processor, the cabinet includes a display screen for maintenance work, the drying compartment is positioned intermediate the printhead and the receiving stage, the drying compartment includes an automatically operated door through which wallpaper is received by the drying compartment, the receiving stage is an exterior well, the receiving stage includes a roller driver and/or the receiving stage is adapted to support a container.
In a particularly preferred form, the selected print is a wallpaper pattern such that the printing system produces wallpaper.
In a third broad embodiment, there is provided a method of producing on-demand wide format printed media web for sale to a consumer, the method including the steps of:
providing a printing system for producing wide format printed media web comprising:

    
    
        at least one media cartridge containing a blank media web;
        a printhead extending at least the width of the media web;
        at least one processor to control printing by the printhead of a selected print on the blank media web to form the wide format printed media web;
        an input device in communication with the at least one processor; and,
        a slitter module to cut the media web to a selected width;
    
    


receiving, from the consumer via the input device, data indicating the selected print and width chosen by the consumer;
printing the selected print on the blank media web;
cutting the wide format printed media web according to the consumer selected width; and,
charging the consumer for the wide format printed media web.
In further particular forms of the invention, samples of prints available for sale are displayed to the consumer in books or collections, the books or collections are provided on racks, such that the consumer can select to modify any of the prints, the data indicating the selected print chosen by the consumer, is received via a touch screen, or via a barcode reader, each of the prints available for sale having an associated barcode. In some forms of the invention, the consumer can browse the prints available for sale, via a computer network, the prints being stored in a remote database. In some embodiments, the consumer can upload or import a new print into the at least one processor. Conveniently, the wide format printed media web is wound and provided to the consumer in a transportable container and/or the wide format printed media web is cut to the selected width and length by a cutter/slitter module.
In a particularly preferred form, the selected print is a wallpaper pattern such that the printing system produces wallpaper.
In a fourth broad embodiment, there is provided a drying system for use in a printing system, the drying system comprising:
an heating element provided within a first chamber;
at least one fan positioned to force air past the heating element;
the first chamber adapted to direct the heated air through an opening into a second drying chamber;
the second drying chamber receiving subsequent portions of a printed media web passed into the second drying chamber through the opening; and,
at least one circulation duct provided to transfer at least a portion of the heated air from the second drying chamber to near the at least one fan.
In further particular forms of the invention, the heating element is controlled by a thermal sensor, more than one heating element is provided, the heating element extends substantially across the width of the first chamber, the at least one fan is a blower or a centrifugal fan, the first chamber tapers towards the opening, each fan is associated with a circulation duct, there are two fans and two circulation ducts, a rotatable door covers the opening, the rotatable door is operated by a winding motor, the second chamber tapers towards the opening, the printed media web is passed into the second chamber as a loose suspended loop, the at least one circulation duct extends from a base region of the second chamber to one side of the at least one fan, the at least one fan is provided external to the first chamber, the at least one fan is substantially encased by an intake duct and/or the intake duct receives at least a portion of air-flow from the at least one circulation duct.
In a fifth broad embodiment, there is provided a composite heating system for use in a printing system, the printing system passing a media web along a media path from a media cartridge, past a printhead, to a printed media exit region, the composite heating system comprising:
a first heating system, disposed between the media cartridge and the printhead, comprising a pre-heater; and,
a second heating system, disposed between the printhead and the printed media exit region, comprising:

    
    
        an heating element provided within a first chamber positioned on one side of the media web;
        at least one fan positioned to force air past the heating element;
        the first chamber adapted to direct the heated air through an opening into a second heating chamber positioned on the other side of the media web; and,
        the second heating chamber receiving subsequent portions of the printed media web passed into the second heating chamber through the opening.
    
    


In a sixth broad embodiment, there is provided a method of drying a printed media web in a printing system, the method including the steps of:
passing a media web along a media path from a media cartridge, past a printhead, and over an opening;
using at least one fan to force air past an heating element provided within a first chamber located on one side of the opening, the first chamber adapted to direct the heated air through the opening into a second drying chamber located on the other side of the opening; and,
driving the printed media web along the media path such that the printed media web extends from the media path, via the opening, into the second drying chamber which receives subsequent portions of the printed media web as the media web is driven along the media path.
In further particular forms of the invention, the heating element is controlled by a thermal sensor, more than one heating element is provided, the heating element extends substantially across the width of the first chamber, the at least one fan is substantially encased by an intake duct and/or the intake duct receives at least a portion of air-flow from the at least one circulation duct.
In a seventh broad embodiment, there is provided a container for receiving wide format printed media web from a printing system, the printing system including a winding area adapted to receive the container, the container comprising:
a casing able to be closed to envelope the wide format printed media web;
a core about which wide format printed media web is wound;
two support members that each associate with opposite distal ends of the core, the support members bearing the load of the wide format printed media web against at least one interior surface of the casing; and,
at least one of the support members including a hub which protrudes through an opening in an end of the casing, the hub adapted to engage with a drive spindle provided in the winding area of the printing system, the drive spindle rotating the hub which results in rotation of the core and consequent winding of the wide format printed media web about the core.
In a preferred embodiment, the wide format printed media web is printed wallpaper.
In further particular forms of the invention, the winding area is external to the printing system, the casing includes a viewing window, the casing includes a handle, the casing is an elongated folded carton, both support members include a hub, the casing includes openings at both ends to receive the hubs, the core is a hollow cylinder, the core is the support members each include a circumferential bearing surface, the circumferential bearing surface is attached to the hub by spokes, the hub is provided with teeth to engage the drive spindle and/or each hub engages a drive spindle.
In an eighth broad embodiment, there is provided a media web cartridge for storing a media web to be introduced into a printing system, the printing system including a region to receive the media web cartridge and feed the media web past a printhead at least as wide as the width of the media web, the media web cartridge comprising:
a casing which envelopes the media web;
a fixed shaft about which the media web is wound and is free to rotate;
two support members that each hold an opposite end of the shaft, the support members adapted to be supported by the casing and to prevent rotation of the shaft relative to the casing;
at least two feed rollers to draw the media web from about the shaft and force the media web through an exit region of the casing; and,
at least one of the feed rollers including a coupling which protrudes through an opening in an end of the casing and is adapted to engage with a drive spindle provided in the printing system, the drive spindle adapted to rotate the at least one feed roller.
In a preferred embodiment, the printing system is a wallpaper printing system wherein the printed media web is wallpaper.
In further particular forms of the invention, the casing is a hinged casing formed of two halves, a distal end of the casing is provided with a handle, a top of the casing is provided with a folding handle, the fixed shaft is a hollow cylinder, the internal diameter of the wound media web is greater than the external diameter of the fixed shaft, the shaft is provided with at least one notch that engages at least one nib of at least one of the support members to prevent rotation of the shaft, at least one of the two support members includes at least one integrated extension that is received by a slot in the casing, there are two extensions, each extension includes a lunette which engages a cooperating groove in at least one of the feed rollers, one of the feed rollers is a driven roller and one of the feed rollers is an idler roller, each support member holds a different feed roller, the coupling includes teeth provided on or in at least one of the feed rollers and/or the exit region is defined by an interface between the halves of the casing when closed.
In a ninth broad embodiment, there is provided printed media web produced by a printing system, the printed media web comprising:
a media web; and,
a print pattern printed on the media web by the printing system;
whereby, the print pattern is selected by a consumer using an input device of the printing system, and the printed media web width is selected by a consumer using the input device; and,
whereby, the printing system for producing the printed media web comprises:

    
    
        at least one media cartridge containing a media web;
        a printhead extending at least the width of the media web;
        at least one processor to control printing by the printhead of the print on the media web;
        the input device in communication with at least one processor; and,
        a slitter device to cut the printed media web to the selected width.
    
    


Preferably, the printing system is a wallpaper printing system wherein the printed media web is wallpaper and the print is a wallpaper pattern.
In further particular forms of the invention, the consumer can browse and select, via a computer network, wallpaper patterns stored in a remote database, the consumer can upload or import a new wallpaper pattern into the at least one processor, the wallpaper is wound in the printing system and provided to the consumer in a transportable container and/or the consumer is able to operate the printing system at the place of purchase of the wallpaper.
In a tenth broad embodiment, there is provided a printhead assembly for a printing system, the printhead assembly comprising:
a casing;
a printhead module, the printhead module comprised of a plurality of printhead tiles arranged substantially along the length of the printhead module;
a fluid channel member held within the casing adjacent the printhead module, the fluid channel member including a plurality of ducts, fluid within each of the ducts being in fluid communication with each of the printhead tiles; and,
each printhead tile including a printhead integrated circuit formed to dispense fluid, a printed circuit board to facilitate communication with a processor controlling the printing, and fluid inlet ports to receive fluid from the fluid channel member.
In a preferred embodiment, the printing system is a wallpaper printing system.
In further particular forms of the invention, the casing houses drive electronics for the printhead, the casing includes notches to engage tabs on the fluid channel member, a printhead tile abuts an adjacent printhead tile, the printhead tiles are supported by the fluid channel member, each of the printhead tiles has a stepped region, the fluid channel member is provided with at least seven ducts, the fluid channel member is formed by injection moulding, the fluid channel member is formed of a material with a relatively low coefficient of thermal expansion, the assembly includes power busbars arranged along the length of the assembly, the fluid channel member is provided with a female end portion at one distal end and a male end portion at the other distal end, more than one fluid channel member can be fixedly associated together in an end to end arrangement, and/or the fluid channel member includes a series of fluid outlet ports arranged along the length of the fluid channel member.
In an eleventh broad embodiment, there is provided a method of printing on-demand wide format printed media web, the method comprising the steps of
receiving input data from a user which identifies a user selected print;
processing data associated with the user selected print to raster and compress the user selected print;
transmitting the compressed print data to a print engine controller;
expanding and rendering the print data in the print engine controller;
extracting a continuous blank media web from a media cartridge;
driving the blank media web past a printhead controlled by the print engine controller using drive means; and,
printing the user selected print using the printhead which extends at least the width of the media web.
In a preferred embodiment, the printing system is a wallpaper printing system wherein the user selected print is a wallpaper pattern.
In further particular forms of the invention, the compressed wallpaper pattern is passed to a memory buffer of the print engine controller, data from the memory buffer is passed to a page image expander, data from the page image expander is passed to dithering means, data from the dithering means and the page image expander is passed to a compositor, data from the compositor is passed to rendering means, the processing data step includes producing page layouts and objects, the print engine controller communicates with a plurality of printhead tiles forming the printhead, the print engine controller communicates with a master quality assurance chip, the print engine controller communicates with an ink cartridge quality assurance chip, the print engine controller includes an interface to the drive means, the print engine controller includes an additional memory interface, the print engine controller includes at least one bi-level buffer and/or the drive means includes at least one driven roller.
In a twelfth broad embodiment, there is provided an ink fluid delivery system for a printer, comprising:
a plurality of ink reservoirs associated in fluid communication with a plurality of ink fluid supply tubes;
at least one ink fluid delivery connector attached to the plurality of ink fluid supply tubes;
an ink fluid supply channel member associated in fluid communication with the at least one ink fluid delivery connector, the ink fluid supply channel member containing a plurality of ducts, at least one duct associated with at least one ink reservoir;
the ink fluid supply channel member provided with a series of groups of outlet ports dispersed along the length of the ink fluid supply channel member; and,
a series of printhead tiles forming a printhead, each printhead tile provided with a group of inlet ports aligned with a group of the outlet ports.
In further particular forms of the invention, there is additionally provided an air pump and at least one air delivery tube to supply air to the printhead, there is provided a detachable coupling in the plurality of ink fluid supply tubes, there are at least six ink reservoirs and six ink supply tubes, the ink reservoirs are provided with ink level monitoring apparatus, an end of the ink fluid supply channel member is provided with a female end portion or a male end portion, the ink fluid supply channel member can engage an adjacent ink fluid supply channel member to provide an extended length, the at least one ink fluid delivery connector has a female end or a male end to engage the ink fluid supply channel member, the at least one ink fluid delivery connector is provided with tubular portions to attach to the plurality of ink fluid supply tubes, the ink fluid supply channel member includes a sealing member at one end, each outlet port in a group is connected to a separate duct, a printhead tile abuts an adjacent printhead tile and/or the series of printhead tiles are supported by the ink fluid supply channel member.
In a thirteenth broad embodiment, there is provided a combined cutter and slitter module for a printer, the combined cutter and slitter module comprising:
at least two end plates, a media web able to pass between the at least two end plates;
at least two slitter rollers rotatably held between the at least two end plates, each of the slitter rollers provided with at least one cutting disk, each of the cutting disks located at different positions along the length of the at least two slitter rollers;
a guide roller positioned to selectively engage with at least one cutting disk, the media web able to be passed between the guide roller and the at least one cutting disk;
a drive motor to rotate the guide roller;
a first actuating motor to selectively rotate the at least two slitter rollers and thereby selectively engage at least one cutting disk with the guide roller;
a transverse cutter positioned along at least the width of the media web; and,
a second actuating motor to force the transverse cutter against the media web.
In a preferred embodiment, the printer is a wallpaper printer.
In further particular forms of the invention, the transverse cutter is fixed to the at least two end plates, at least two entry rollers are fixed between the at least two end plates, at least one of the entry rollers is powered, the drive motor also drives the at least one entry roller, the at least two slitter rollers are provided with two or more cutting disks, the position of at least one of the two or more cutting disks varies between each of the at least two slitter rollers, there are four slitter rollers, the guide roller is provided with circumferential recesses to engage the at least one cutting disk, the at least two slitter rollers are mounted on two brackets which are rotatably attached to the at least two endplates, a stabilising shaft is provided between the two brackets, at least two exit rollers are fixed between the at least two end plates, at least one of the exit rollers is powered, the drive motor also drives the at least one exit roller and/or a blade of the cutter is mounted between a pair of rotating cams.
In a fourteenth broad embodiment, there is provided a printhead tile for use in a printing system, the printhead tile comprising:
a printhead integrated circuit including an array of ink nozzles;
a channel layer provided adjacent the printhead integrated circuit, the channel layer provided with a plurality of channel layer slots;
an upper layer provided adjacent the channel layer, the upper layer provided with an array of upper layer holes on a first side, and an array of upper layer channels on a second side, at least some of the upper layer holes in fluid communication with at least some of the upper layer channels, and at least some of the upper layer holes aligned with a channel layer slot;
a middle layer provided adjacent the upper layer, the middle layer provided with a plurality of middle layer holes, at least some of the middle layer holes aligned with at least some of the upper layer channels; and,
a lower layer provided adjacent the middle layer, the lower layer provided with an array of inlet holes on a first side, and an array of lower layer channels on a second side, at least one of the inlet holes in fluid communication with at least one of the lower layer channels, and at least some of the middle layer holes aligned with a lower layer channel;
whereby, the inlet holes receive different types or colors of ink, each type or color of ink separately transported to different nozzles of the printhead integrated circuit.
In further particular forms of the invention, the upper layer and the middle layer each include one or more air holes, the lower layer includes at least one air channel, an endplate is provided adjacent the channel layer, the channel layer slots are provided as fingers integrated in the channel layer, the printhead integrated circuit is bonded onto the upper layer, the array of ink nozzles overlie the array of upper layer holes, the channel layer acts to direct air flow across the printhead integrated circuit, the diameter of holes decreases from the inlet holes to the middle layer holes to the upper layer holes and/or additionally including a nozzle guard adjacent the printhead integrated circuit.
In a preferred embodiment, the printing system is a wallpaper printing system.
In a fifteenth broad embodiment, there is provided a printhead assembly with a communications module for a printing system, the printhead assembly comprising:
a casing;
a printhead module;
a fluid channel member positioned adjacent to the printhead module, the fluid channel member including a plurality of ducts that substantially span the length of the printhead module;
a power supply connection port positioned at a distal end of the casing, the power supply port electrically connected to at least one busbar that substantially spans the length of the printhead module;
a fluid delivery connection port positioned at a distal end of the casing, the fluid delivery port in fluid communication with the fluid channel member; and,
a data connection port positioned at a distal end of the casing, the data port electrically connected to at least one printed circuit board positioned within the casing, the at least one printed circuit board further electrically connected to the printhead module.
In a preferred embodiment, the printing system is a wallpaper printing system.
In further particular forms of the invention, each printhead tile is in electrical connection with the power supply port, data communication with the data port and fluid communication with the fluid delivery port, the power supply connection port and the data connection port are mounted on a connection platform attached to or part of the casing, the connection platform includes a spring portion, the spring portion is at least one integrated serpentine member of the connection platform and/or an endplate is disposed between the casing and the connection ports.
In a sixteenth broad embodiment, there is provided a printer provided with a micro-electro-mechanical printhead for producing printed media, the printer comprising:
a micro-electro-mechanical printhead extending at least the width of a media web;
drive means to drive the media web past the printhead;
at least one processor to receive and process a selected print and to control printing of the selected print, by the printhead, on the media web;
the printhead including of a plurality of printhead tiles arranged along the length of the printhead;
a fluid channel member adjacent the printhead;
each printhead tile including a series of micro-electro-mechanical nozzle arrangements, each nozzle arrangement in fluid communication with the fluid channel member; and,
each nozzle arrangement comprising:

    
    
        a nozzle chamber for holding fluid;
        a lever arm for forcing at least part of the fluid from the nozzle chamber;
        an actuator beam for distorting the lever arm; and,
        at least one electrode for receiving an electrical current that heats and expands the actuator beam.
    
    


In a preferred embodiment, the printing system is a wallpaper printing system wherein the selected print is a wallpaper pattern and the printed media is wallpaper.
In further particular forms of the invention, the lever arm forms a rim of the nozzle chamber, the rim includes radial recesses, each nozzle arrangement includes an anchor for the actuator beam, the nozzle chamber includes a fluidic seal, the drive means is at least one driven roller, the drive means comprises a driven roller associated with an idler roller, each printhead tile abuts an adjacent printhead tile, each of the printhead tiles has a stepped region, each printhead tile is in electrical connection with a power supply and data communication with the at least one processor and/or each nozzle arrangement is positioned on a substrate.
In a seventeenth broad embodiment, there is provided a mobile printer for producing wide format printed media, the printer comprising:
a vehicle adapted to hold and transport the printer;
input means for a consumer to choose a selected print to be printed on a media web to form the wide format printed media;
at least one media cartridge containing the media web;
a printhead extending at least the width of the media web;
drive means to drive the media web past the printhead; and,
at least one processor to receive and process the selected print and to control printing of the selected print.
Preferably, the printing system is a wallpaper printing system wherein the selected print is a wallpaper pattern and the wide format printed media is wallpaper.



BRIEF DESCRIPTION OF THE FIGURES
Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 is a perspective view of a wallpaper printer according to the teachings of the present invention;
FIG. 2 is a perspective view of a typical retail setting, illustrating the deployment of the present invention;
FIG. 3 is an exploded perspective view of a wallpaper printer of the type depicted in FIG. 1;
FIG. 4 is a perspective view of a wallpaper printer with a service door open;
FIG. 5 is a cross section through the device depicted in FIG. 1;
FIG. 6 is a detail of the cross section depicted in FIG. 5;
FIG. 7 is a cross section through a wallpaper printer depicting a wallpaper production paper path;
FIG. 8A is a top plan view of a dryer cabinet;
FIG. 8B is an elevation of a dryer cabinet;
FIG. 8C is a side elevation of a dryer cabinet;
FIG. 9 is a perspective view of a dryer cabinet;
FIG. 10 is a perspective view of the printhead and ink harness;
FIG. 11 is another perspective view of the printhead and ink harness showing removal of the printhead;
FIG. 12 is a perspective view of a slitter module;
FIG. 13 is another perspective of a slitter module showing the transverse cutter;
FIGS. 14A and 14B are perspective views of a media cartridge;
FIG. 15 is a perspective view of the media cartridge depicted in FIG. 14 with the case open;
FIG. 16 in an exploded perspective of an interior of a media cartridge;
FIGS. 17A and 17D are various views of the media cartridge depicted in FIGS. 14-16;
FIG. 18 is a cross section through a media cartridge;
FIG. 19 is a perspective view of a carry container or finished wallpaper product; and
FIG. 20 is an exploded perspective of the container depicted in FIG. 19;
FIG. 21 shows a perspective view of a printhead assembly in accordance with an embodiment of the present invention;
FIG. 22 shows the opposite side of the printhead assembly of FIG. 21;
FIG. 23 shows a sectional view of the printhead assembly of FIG. 21;
FIG. 24A illustrates a portion of a printhead module that is incorporated in the printhead assembly of FIG. 21;
FIG. 24B illustrates a lid portion of the printhead module of FIG. 24A;
FIG. 25A shows a top view of a printhead tile that forms a portion of the printhead module of FIG. 24A;
FIG. 25B shows a bottom view of the printhead tile of FIG. 25A;
FIG. 26 illustrates electrical connectors for printhead integrated circuits that are mounted to the printhead tiles as shown in FIG. 25A;
FIG. 27 illustrates a connection that is made between the printhead module of FIG. 24A and the underside of the printhead tile of FIGS. 25A and 25B;
FIG. 28 illustrates a “female” end portion of the printhead module of FIG. 24A;
FIG. 29 illustrates a “male” end portion of the printhead module of FIG. 24A;
FIG. 30 illustrates a fluid delivery connector for the male end portion of FIG. 29;
FIG. 31 illustrates a fluid delivery connector for the female end portion of FIG. 28;
FIG. 32 illustrates the fluid delivery connector of FIGS. 30 or 31 connected to fluid delivery tubes;
FIG. 33 illustrates a tubular portion arrangement of the fluid delivery connectors of FIGS. 30 and 31;
FIG. 34A illustrates a capping member for the female and male end portions of FIGS. 28 and 29;
FIG. 34B illustrates the capping member of FIG. 34A applied to the printhead module of FIG. 24A;
FIG. 35A shows a sectional (skeletal) view of a support frame of a casing of the printhead assembly of FIG. 21;
FIGS. 35B and 35C show perspective views of the support frame of FIG. 35A in upward and downward orientations, respectively;
FIG. 36 illustrates a printed circuit board (PCB) support that forms a portion of the printhead assembly of FIG. 21;
FIGS. 37A and 37B show side and rear perspective views of the PCB support of FIG. 36;
FIG. 38A illustrates circuit components carried by a PCB supported by the PCB support of FIG. 36;
FIG. 38B shows an opposite side perspective view of the PCB and the circuit components of FIG. 38A;
FIG. 39A shows a side view illustrating further components attached to the PCB support of FIG. 36;
FIG. 39B shows a rear side view of a pressure plate that forms a portion of the printhead assembly of FIG. 21;
FIG. 40 shows a front view illustrating the further components of FIG. 39;
FIG. 41 shows a perspective view illustrating the further components of FIG. 39;
FIG. 42 shows a front view of the PCB support of FIG. 36;
FIG. 42A shows a side sectional view taken along the line I-I in FIG. 42;
FIG. 42B shows an enlarged view of the section A of FIG. 42A;
FIG. 42C shows a side sectional view taken along the line II-II in FIG. 42;
FIG. 42D shows an enlarged view of the section B of FIG. 42C;
FIG. 42E shows an enlarged view of the section C of FIG. 42C;
FIG. 43 shows a side view of a cover portion of the casing of the printhead assembly of FIG. 21;
FIG. 44 illustrates a plurality of the PCB supports of FIG. 36 in a modular assembly;
FIG. 45 illustrates a connecting member that is carried by two adjacent PCB supports of FIG. 44 and which is used for interconnecting PCBs that are carried by the PCB supports;
FIG. 46 illustrates the connecting member of FIG. 45 interconnecting two PCBs;
FIG. 47 illustrates the interconnection between two PCBs by the connecting member of FIG. 45;
FIG. 48 illustrates a connecting region of busbars that are located in the printhead assembly of FIG. 21;
FIG. 49 shows a perspective view of an end portion of a printhead assembly in accordance with an embodiment of the present invention;
FIG. 50 illustrates a connector arrangement that is located in the end portion of the printhead assembly as shown in FIG. 49;
FIG. 51 illustrates the connector arrangement of FIG. 50 housed in an end housing and plate assembly which forms a portion of the printhead assembly;
FIGS. 52A and 52B show opposite side views of the connector arrangement of FIG. 50;
FIG. 52C illustrates a fluid delivery connection portion of the connector arrangement of FIG. 50;
FIG. 53A illustrates a support member that is located in a printhead assembly in accordance with an embodiment of the present invention;
FIG. 53B shows a sectional view of the printhead assembly with the support member of FIG. 53A located therein;
FIG. 53C illustrates a part of the printhead assembly of FIG. 53B in more detail;
FIG. 54 illustrates the connector arrangement of FIG. 50 housed in the end housing and plate assembly of FIG. 51 attached to the casing of the printhead assembly;
FIG. 55A shows an exploded perspective view of the end housing and plate assembly of FIG. 51;
FIG. 55B shows an exploded perspective view of an end housing and plate assembly which forms a portion of the printhead assembly of FIG. 21;
FIG. 56 shows a perspective view of the printhead assembly when in a form which uses both of the end housing and plate assemblies of FIGS. 55A and 55B;
FIG. 57 illustrates a connector arrangement housed in the end housing and plate assembly of FIG. 55B;
FIGS. 58A and 58B shows opposite side views of the connector arrangement of FIG. 57;
FIG. 59 illustrates an end plate when attached to the printhead assembly of FIG. 49;
FIG. 60 illustrates data flow and functions performed by a print engine controller integrated circuit that forms one of the circuit components shown in FIG. 38A;
FIG. 61 illustrates the print engine controller integrated circuit of FIG. 60 in the context of an overall printing system architecture;
FIG. 62 illustrates the architecture of the print engine controller integrated circuit of FIG. 61;
FIG. 63 shows an exploded view of a fluid distribution stack of elements that form the printhead tile of FIG. 25A;
FIG. 64 shows a perspective view (partly in section) of a portion of a nozzle system of a printhead integrated circuit that is incorporated in the printhead module of the printhead assembly of FIG. 21;
FIG. 65 shows a vertical sectional view of a single nozzle (of the nozzle system shown in FIG. 64) in a quiescent state;
FIG. 66 shows a vertical sectional view of the nozzle of FIG. 65 at an initial actuation state;
FIG. 67 shows a vertical sectional view of the nozzle of FIG. 66 at a later actuation state;
FIG. 68 shows in perspective a partial vertical sectional view of the nozzle of FIG. 65, at the actuation state shown in FIG. 66;
FIG. 69 shows in perspective a vertical section of the nozzle of FIG. 65, with ink omitted;
FIG. 70 shows a vertical sectional view of the nozzle of FIG. 69;
FIG. 71 shows in perspective a partial vertical sectional view of the nozzle of FIG. 65, at the actuation state shown in FIG. 66;
FIG. 72 shows a plan view of the nozzle of FIG. 65;
FIG. 73 shows a plan view of the nozzle of FIG. 65 with lever arm and movable nozzle portions omitted;
FIGS. 74-76 illustrate the basic operational principles of an embodiment of a nozzle;
FIG. 77 illustrates a three dimensional view of a single ink jet nozzle arrangement;
FIG. 78 illustrates an array of the nozzle arrangements of FIG. 77;
FIG. 79 shows a table to be used with reference to FIGS. 80 to 89;
FIGS. 80 to 89 show various stages in the manufacture of the ink jet nozzle arrangement of FIG. 77; and
FIG. 90 illustrates a method of sale for printed wallpaper.



BEST MODE AND OTHER EMBODIMENTS OF THE INVENTION
1. Exterior Overview
As shown in FIG. 1 a wallpaper printer 100 comprises a cabinet 102 with exterior features to facilitate the specification of, purchase of, and packaging of wallpaper which is selected and printed, on-demand, for example at a point of sale. The cabinet 102 includes input means, for example a tilting touch screen interface 104 such as an LCD TFT screen which may be positioned at a convenient height for a standing person. The cabinet may also support a pistol grip type barcode scanner 108 which serves as a data capture device and input. The scanner 108 is preferably attached to the cabinet 102 by a data cable or a tether 110, even if the scanner 108 operates over a wireless network.
The cabinet may additionally be provided with wired or wireless connection to a network, enabling a processor within the cabinet to communicate with remote information sources.
The cabinet 102 includes a winding area, in this example taking the form of an exterior well 106 for receiving a container for printed wallpaper, as will be further explained. The well holds a specially configured container 208 (see FIGS. 4 and 5). The container holds a winding core onto which is wound a roll of wallpaper for purchase. The well includes a pair of spindles 120, at least one of which is driven by a motor and which align, engage and rotate the winding core within the container 208. The cabinet also includes a tape dispenser 112 with a lid which is used by the machine operator to dispense tape for attaching the wallpaper media to the disposable winding core in the container 208, as will be further explained.
Other exterior cabinet features include a vent area 114 on the top of the cabinet for the discharge of heated or moist air. The vent or vent area 114 is covered by a top plate 116. The cabinet includes one or more service doors 402. When the service door is open, the media cartridges 400 can be inserted or withdrawn by their handles 1408. Adjustable feet 122 may be provided. The cabinet is preferably built around a frame (see FIG. 3) clad with stainless steel and may be decorated with ornamental insert panels 118.
2. Operation Overview
As shown in FIG. 2, the wallpaper printer of the present invention 100 can serve as the production facility of a business operation such as a retail operation. In this Figure, it can be seen that wallpaper samples or swatches may be arranged into books or collections 200 and displayed on racks 202 for easy access by consumers. In short, a consumer 204 selects a wallpaper pattern from a collection 200 or bases a selection on the modification of an existing pattern. A machine operator scans an associated barcode or other symbol of that pattern with the scanner 108 or enters an alphanumeric code through the touch screen 104 (or other interface) to the printer's processor. Rolls of wallpaper are produced in standardized boxes or totes 208, on demand and according to consumer preferences which are input to the printer. Consumer preferences might include a selection of a pattern, a variation to the basic pattern, a custom pattern, the width and length of the finished product, or the web or substrate type onto which the pattern is printed.
After the appropriate selections have been made, a free end of a roll of media (already protruding from the exit slot 206 adjacent to the well 106) is taped to a winding core, for example with tape which is provided by the tape dispenser 112 (see FIG. 1). The disposable core (see 2014 in FIG. 20) is supported within a box 208. As the selected wallpaper is printed and dispensed from the slot 206, it is wound onto the winding core 2014. At the end of the production run of a particular roll, the web of printed wallpaper is separated with a transverse knife located with the cabinet. By further advancing the winding core, the trailing end of the roll is taken up into the container 208. When the winding is complete winding spindle may be disengaged from the box 208 allowing it to be withdrawn from the well 106 (see FIG. 1).
In some embodiments, a consumer of wallpaper may operate the printer. In other embodiments an operator with some degree of training may operate the machine in accordance with a customer's requirements, preferences or instructions.
It will be appreciated that this kind of operation provides the basis for a wallpaper printing business or the deployment of a franchise based on the technology.
In a franchise setting, a head licensor supplies the printer to franchisees. The licensor may also supply the consumables such as inks, media, media cartridges, totes, cores etc. As each of these items potentially require quality control supervision and therefore supply from the licensor in order to ensure the success of the franchise, their consumption by the franchisee may also serve as metrics for franchisee performance and a basis for franchisor remuneration. The franchisor may also supply new patterns and collections of patterns as software, in lieu of actual physical inventory. New patterns insure that the franchisees are able to exploit trends, fashions and seasonal variances in demand, without having to stock any printed media. A printer of this kind may be operated as a networked device, allowing for networked accounting, monitoring, support and pattern supply, also allowing decentralized control over printer operation and maintenance.
The printing system 100 may also facilitate the option for the consumer to load or import a desired wallpaper pattern into the processing system of the printer. For example, a consumer may have independently created or located a desired wallpaper pattern which the consumer can load or import into the printing system 100 so that the consumer can print customised wallpaper. This facility can be achieved by a variety of means, for example, the consumer may input wallpaper pattern data, in any of a variety of data formats, by inserting a diskette, CD, USB memory stick, or other memory device into a data loading port (not illustrated) of the printing system 100. In another form, the consumer may operate a terminal associated with the printing system 100 to locate and download wallpaper pattern data from a remote information source, for example using the Internet.
3. Construction Overview
As shown in FIG. 3, the cabinet 100 is built around a frame 300. The frame 300 supports the outer panels, e.g. side panels 302, 304, a rear panel 306, upper and lower front panels 308 310 and a top panel 312. The well 106 is shown as having a support spindle 330 and a driven spindle 314. Tracing the paper flow path backward from the well 106, the path comprises a slitter and transverse cutter module 316, a dryer 318, a full width stationery printhead 320, and the media cartridges with their drive mechanism 322. Ink reservoirs 324 are located above the printhead 320. The reservoirs may have level monitors or quality control means that measure or estimate the amount of ink remaining. This quantity may be transmitted to the printer's processor where it can be used to generate a display or alarm. The processing capabilities of the device are located in a module or enclosure 340. The processor operates the unit in accordance to stored technical and business rules in conjunction with operator inputs.
As shown in FIG. 4, wallpaper media, before it is printed, is contained in cartridges 400. In this example there is an uppermost cartridge located in a loading area, ready for use and two other cartridges in storage located below it. As will be explained, the printer is self threading and no manual intervention is required by the machine operator to thread the web of unprinted paper into the printing system other than to load the upper cartridge 400 correctly. The service door 402 provides access to the media cartridges 400 and required machine interfaces as well as to the ink reservoirs 324. Ink reservoirs 324 hold up to several liters of ink and are easily removed and interchanged through the service door 402. An instruction panel or display screen 410 may be provided at or near eye level.
As the printer is self-threading, it is possible that a media cartridge 400 may be automatically loaded into position without manual intervention. For example, a series of media cartridges may be provided in a form of carousel, such as a linear stepped carousel or rotating carousel. When a media cartridge is exhausted of blank media web, or the processing system determines there is insufficient remaining blank media web for a wallpaper printing job, the media cartridge can be rotated or moved out of alignment with the pilot guides 512 and a new media cartridge rotated or moved into alignment with the pilot guides 512.
In a further particular embodiment, the printing system 100 can be provided as a transportable device. For example the printing system 100 can be carried by or integrated with a vehicle, such as a van or light truck. This allows the printing system 100 to be mobile and offer a service whereby the vehicle is driven to a consumer's home or premises where the consumer can select desired wallpaper. Such a mobile printing system 100 might be used to initially print a sample of wallpaper to be tested or judged in the position or location of the wallpapers intended use.
A consumer can purchase on-demand wallpaper which is offered for sale to the consumer. In a particular embodiment of the present invention, and referring to FIG. 90, the method of sale 9000 includes step 9010 of providing the printing system for producing wallpaper, receiving at step 9020, from the consumer via an input device, data 9030 indicating the consumer selected wallpaper pattern and any wallpaper width parameters, printing at step 9040 the selected wallpaper pattern on the blank media web, cutting at step 9050 the printed wallpaper according to any consumer selected width, and, at step 9060 charging the consumer for the wallpaper.
4. Printhead and Ink
The embodiment shown uses one of the applicant's MemjetTM printheads. A typical example of these printheads is shown in PCT application Ser. No. PCT/AU98/00550, the entire contents of which is incorporated herein by reference.
As shown in FIG. 5, the printhead 500 is preferably a MemjetTM style printhead which delivers 1600 dpi photographic quality reproduction. The style of printhead is fabricated using micro electro-mechanical techniques so as to deliver an essentially all silicon printhead with 9290 nozzles per inch or more than 250,000 nozzles covering a standard roll width of 27 inches. The media web 420 (see FIGS. 6 and 7) is delivered past the stationary printhead at 90 feet per minute, allowing wallpaper for a standard sized room to be printed and packaged in about 2 minutes. FIGS. 10 and 11 show the elongated printhead 500 carried by a rail 502. The rail allows the printhead to be easily removed and installed, for service, maintenance or replacement by sliding motion, into and out of position.
Referring again to FIG. 5, the printhead is supplied with liquid ink from the reservoirs 324. The removable reservoirs are located above the printhead 500 and a harness 504 comprising a number of ink supply tubes 1012 carries the 6 different ink colors from the 6 reservoirs 324 to the printhead 500. The liquid ink harness 504 is interrupted by a self sealing coupling 1002, 1004 (see FIGS. 10 and 11). Furthermore, by loosening thumb screws 1006 and disconnecting the ink harness coupling 1002, 1004 allows the printhead to be withdrawn from the rail 502. Also note that an air pump 1010 supplies compressed air through an air hose 1011 to the printhead or an area adjacent to it. This supply of air may be used to blow across the nozzles in order to prevent the media from resting on the nozzles.
Rail microadjusters 1014 (see FIGS. 6 and 10) are used to accurately adjust the distance or space that defines a gap between the printheads and the media being printed.
As shown in FIG. 6, a capper motor 602 drives a rotary capping and blotting device. The capping device seals the printheads when not in use in order to prevent dust or contaminants from entering the printheads. It uncaps and rotates to produce an integral blotter, which is used for absorbing ink fired from the printheads during routine printer start-up maintenance.
5. Media Path
As shown in FIGS. 5, 6 and 7, the printhead 500 resides in an intermediate portion of a media path which extends from a blank media input near the upper cartridge 400 to the printed wallpaper exit slot near the winding roll 2014 (see FIG. 20). The media path is able to be threaded without user intervention because the media is guided at all times in the path. In some embodiments, the path extends to within the tote or container 208. The path extends in a generally straight line from cartridge 400, across a very short gap to between the pilot guides 512, across a flat pre-heater or platen 510 to a location under the printhead 500 and thereafter across an opening 506 which defines the mouth of the dryer's drying compartment 520. The opening into the compartment 520 is covered by a rotating door 508. The door is closed, except during printing which requires air drying. As shown in FIG. 7, the door 508 of the dryer 318 can be opened so that the media web 420 descends, following a catenary path when required, into the compartment 520, providing additional path length and drying time. The path may form a catenary loop or strictly speaking, a loop portion which is suspended within the compartment from each end. In one embodiment the door 508 is biased into an open position and closed by the action of a winding motor 522 operated by the printer's processor.
After the dryer 318, the path continues in a generally straight line to the cutting and slitting or module 316. The media path then extends from the cutting and slitting module 316 through the exit opening 206 of the cabinet.
6. The Dryer
As shown in FIGS. 8 and 9, the removable drying cabinet or module 318 utilizes one or more top mounted blowers or centrifugal fans 800. The fans 800 provide a supply of air, downward through a chamber 808 (also referred to as a plenum), across one or more heating elements 802 that are controlled by a thermal sensor 804. The stream of heated air is channeled by a tapered duct 806 and blown across the opening 506 (not shown in these Figures). When the door 508 is open, the heated air blows into the drying compartment 520. Exterior circulation ducts 812 allow air from the drying compartment 520 to be collected and supplied to the intakes 814 of each motor 800. The ducts extend from vents in the compartment upwardly and may include an upper vent 902 which allows hot or moist air to escape through the vent area 114 of the cabinet.
7. The Slitter/Cutter Module
FIGS. 12 and 13 illustrate the slitter/cutter module 1200. The module 1200 comprises a frame, such as a sheet metal frame 1202 having end plates 1204 and 1206. The paper path through the module 1200 is defined by a pair of entry rollers 1208 and 1210 and a pair of exit rollers 1212 and 1214. One of the entry rollers 1208 and one of the exit rollers 1212 is powered. Power is supplied to both drive rollers by a drive motor 1216 and a drive belt 1218. The drive rollers 1208, 1212 in conjunction with the idler rollers 1210, 1214 serve as a transport mechanism for the wallpaper through the module 1200.
Also located between the side plates 1204, 1206 is an optional, slitter gang or mechanism in a rotating carrousel configuration. The slitter gang comprises a separate pair of brackets or end plates 1220 and 1222 between which extend a plurality of slitter rollers 1224, 1226, 1228 and 1230 and a central stabilizing shaft 1232. In this example, four independent rollers are depicted along with a stabilizing shaft 1232. It will be understood that the slitter gang is optional and may be provided either as a single roller or a gang of two or more rollers as illustrated by FIG. 12. An actuating motor 1232 rotates the slitter gang into a selected position. A central guide roller 1234 extends between the end plates 1204, 1206 and beneath the slitter gang. The guide roller 1234 has a succession of circumferential grooves 1236 formed along its length. The grooves 1236 correspond to the position of each of the blades, cutters or rotating cutting disks 1238 which are formed on each of the slitters 1224-1230. In this way, the guide roller acts as a cutting block and allows the blades 1238 to penetrate the wallpaper when they are rotated into position. In this way, each of the slitters 1224-1230 can be rotated into an out of position, as required.
As shown in FIG. 13, the exit portion of the slitter/cutter module 1200 comprises a transverse cutter 1300. The cutter blade 1300 is mounted eccentrically between a pair of rotating cams 1302 which are rotated in unison by an actuating motor 1304 to provide a circular cutting stroke. The motor may be mounted on an end plate 1306. Actuation of the cutter 1300 divides the wallpaper web.
8. Media Supply Cartridge
FIGS. 14-18 illustrate the construction of the wallpaper media supply cartridges 400. Each cartridge comprises, for example, a high density polyethylene molding which forms a hinged case 1400. The case 1400 includes a top half 1402 and a bottom half 1404 which are held together by hinge such as an integral hinge 1406. One end face of the cartridge 400 preferably includes a handle 1408. A second folding handle 1410 may be provided, for ease of handling, along the top of the cartridge 400. The two halves, 1402, 1404, may be held together by one or more resilient clips 1414.
As shown in FIG. 16, the cartridge 400 is preferably loaded by introducing an assembly into the bottom case half. The assembly includes a roll of blank media 1600 on a hollow core 1630 which rotates freely about a shaft 1610, rollers 1620, 1622 and the support moldings 1614.
The shaft 1610 carries a roller support molding 1614 at each end. The may be interchangeable so as to be used at either end. A notch 1632 at each end of the shaft 1610 engages a cooperating nib 1634 on the support moldings. Because the support moldings 1614 are restrained from rotating by locator slots 1636 formed in the cases halves, the shaft does not rotate (but the media roll 1600 does). The roller support moldings also may include resilient extensions 1616. Lunettes 1638 at the end of the extensions engage cooperating grooves 1618 formed at the ends of the cartridge drive roller 1620 and idler roller 1622. The rollers 1620, 1622 are supported between the ends of the cartridge 400, but maintained in proximity to one another and in registry with the shaft 1610 by the support moldings 1614. The resilient force imposed by the extensions 1616 keep the drive roller 1620 and the idler 1622 in close enough proximity (or in contact) that when the drive roller 1620 is operated on by the media driver motor, the wallpaper medium is dispensed from the dispensing slot 1640 of the cartridge 400. Further advancing the drive roller 1620 advances the media web into the media path.
In some embodiments, the driven roller 1620 is slightly longer than the idler roller 1622. One case half has an opening 1650 which allows a shaft or spindle to rotate the drive roller 1620 via a coupling half 1652 formed in the roller. The opening may serve as a journal for the shaft 1620. The idler roller remains fully within the case when the halves are shut.
The media web 420 held by the media cartridge 400 may be a completely blank media web, a blank colored media web, a media web with background patterns already provided, or a media web with any form of black or colored indicia already provided on the media web. The media web may be formed from any of a variety of types of medium, such as, for example, plain, glossed, treated or textured paper.
9. Customer Tote
As shown in FIGS. 19 and 20, a tote or container 1900 for the finished product comprises an elongated folding carton with a central axially directed opening 1902 at each end 1902. The carton may be disposable and formed from paper, cardboard or any other thin textile. The carton holds about 50 meters of printed wallpaper. As shown in FIG. 20, the finished roll of wallpaper 2000 is shown on a core 2008 supported between a pair of support moldings 2002 and 2004. The core 2008 may be disposable. Each of the support moldings comprises a hub or stub shaft 2006 which is adapted to engage the interior of the core 2008 which carries the printed wallpaper 2000. The support moldings may have a circumferential bearing surface 2010, attached to the stub shaft 2006, for example by spokes 2030, for distributing the load onto the interior bottom and walls of the carton. Each molding, 2002, 2004 includes an external shoulder 2012 which is adapted to fit through the openings 1902. At least one of the moldings 2002 has axially or radially extending teeth on shoulder 2012 forming a coupling feature which is adapted to be driven by the drive mechanism located within the cradle 106 formed on the front of the cabinet. Other types of coupling features may be used. A viewing window 2020 may be formed in an upper flap of the carton 1900 so that the printed pattern can be viewed with the lid 2022 closed.
An edge 1920 of the carton adjacent to the lid 2022 may include a return fold so as to smooth the edge presented to wallpaper as it is wound onto the core. A smooth edge may also be provided by applying a separate anti-friction material. Note the gap 1922 between the lid and the carton. Wallpaper enters the tote through the gap 1922.
The carton 1900 may include folding handles 1910 provided singly or in opposing pairs, 1910, 1912. In some embodiments a handle is provided on either side of the gap 1922. Folding handles of this kind form a grip when deployed but do not interfere with the location of the box 1900 within the cradle. An arrow 1914 or other visual device printed on the box indicates which end of the carton orients to or corresponds to the driving end of the cradle 106 (see FIG. 3).
10. Information Processing
The invention has been disclosed with reference to a module 340 in which is placed a processor. It will be understood that the processing capabilities of the printer of the present invention may be physically deployed and interconnected with the hardware and software required for the printer in a number of ways. In this document and the claims, the broad term “processor” is used to refer to the totality of electronic information processing resources required by the printer (regardless of location, platform, arrangement, network, configuration etc. ) unless a contrary intention or meaning is indicated. In general the processor is responsible for coordination of the printer's functions in accordance with the operator inputs. The printer's functions may include any one or more of: providing operator instruction, creating alerts to system performance, self threading, operation of the printhead and its accessory features, obtaining operator inputs from any of a variety of sources, movement of the web through the printer and out of it, operation of any cutter or slitter, winding of the finished roll onto a spool or into a tote, communication with the operator and driving any display, self diagnosis and report, self maintenance, monitoring system parameters and adjusting printing systems.
In a particular embodiment, the processing system 340 of the wallpaper printer 100 is generally associated with or includes at least a processor or processing unit, a memory, an associated input device 104 and/or 108 and an output device 104 or printhead 500, coupled together via a bus or collection of buses. An interface can also be provided for coupling the processing system 340 to a storage device which houses a database. The memory can be any form of memory device, for example, volatile or non-volatile memory, solid state storage devices, magnetic devices, etc. The input device receives data input and can include, for example, a touchscreen, a keyboard, pointer device, barcode reader, voice control device, data acquisition card, etc. The output device can include, for example, a display device, monitor, printer, etc. The storage device can be any form of storage means, for example, volatile or non-volatile memory, solid state storage devices, magnetic devices, etc. In use, the processing system can be adapted to allow data or information to be stored in and/or retrieved from the database. The processor receives instructions via the input device. It should be appreciated that the processing system may be any form of processing system, computer, server, specialised hardware, or the like.
In a further particular embodiment, the printer 100 may be part of a networked data communications system, in which a consumer can be provided with access to a terminal, remote or local to the printer 100, or which is capable of requesting and receiving information from other local or remote information sources, eg. databases or servers. In such a system a terminal may be a type of processing system, computer or computerised device, a personal computer (PC), a mobile or cellular phone, a mobile data terminal, a portable computer, a personal digital assistant (PDA) or any other similar type of electronic device. Thus, in one embodiment the consumer may request, and possibly also pay for, printed wallpaper with a particular pattern via, for example, a mobile telephone interface, and then collect or have delivered the printed wallpaper. The capability of a terminal to request and/or receive information from the wallpaper printer's processing system can be provided by an application program, hardware, firmware, etc. A terminal may be provided with associated devices, for example a local storage device such as a hard disk drive or solid state drive to store a consumer's past choices or preferences, and/or a memory of the wallpaper printer or associated remote storage may store a consumer's past choices or preferences, and possibly other information about the purchase.
An information source that may be remotely associated with the wallpaper printer can be a server coupled to an information storage device. The exchange of information between the printer and the information source is facilitated by communication means. The communication means can be realised by physical cables, for example a metallic cable such as a telephone line, semi-conducting cables, electromagnetic signals, for example radio-frequency signals or infra-red signals, optical fibre cables, satellite links or any other such medium or combination thereof connected to a network infrastructure.
The network infrastructure can include devices such as a telephone switch, a base station, a bridge, a router, or any other such specialised component, which facilitates the connection between the printer 100 and an information source. For example, the network infrastructure may be a computer network, telecommunications network, data communications network, Local Area Network (LAN), Wide Area Network (WAN), wireless network, Internetwork, Intranetwork, the Internet and developments thereof, transient or temporary networks, combinations of the above or any other type of network.
11. Methods of Operation
The device of the present invention is preferably operated as an on demand printer. An operator of the device is able to select a pattern for printing in a number of ways. The pattern may be selected by viewing pattern on the display 104, or from a collection of printed swatches 200 or by referring to other sources. The identity of the selected pattern is communicated to the printer by the scanner 108 or by a keyboard, the touchscreen 104 or other means. In some embodiments the pattern may be customized by operator input, such as changing the color or scale of a pattern, the spacing of stripes or the combination of patterns. Input devices such as the touchscreen 104 also allow the customer, user or operator to configure the printer for a particular run or job. Configuration information that can be input to the processor includes roll length, slitting requirements, media selection or modifications to the pattern. The totality of inputs are processed and when the printer is ready to print, the operator insures that the web is taped to the core in the tote and that the core and tote are ready for winding. Alerts will be generated by the printer if any system function or parameter indicates that the job will not be printed and wound successfully. This may require the self diagnosis of a variety of physical parameters such as ink fill levels, remaining web length, web tension, end-to-end integrity of the web etc. Information requirements and resources may be parsed and checked as well prior to the initiation of a print run. Once the required roll length has been wound, the tote is severed from the web, either automatically or manually, as required.
A detailed description of a preferred embodiment of the printhead will now be described with reference to FIGS. 21-73.
The printhead assembly 3010 as shown in FIGS. 21 and 22 is intended for use as a page width printhead in a printing system. That is, a printhead which extends across the width or along the length of a page of print media, e.g., paper, for printing. During printing, the printhead assembly ejects ink onto the print media as it progresses past, thereby forming printed information thereon, with the printhead assembly being maintained in a stationary position as the print media is progressed past. That is, the printhead assembly is not scanned across the page in the manner of a conventional printhead.
As can be seen from FIGS. 21 and 22, the printhead assembly 3010 includes a casing 3020 and a printhead module 3030. The casing 3020 houses the dedicated (or drive) electronics for the printhead assembly together with power and data inputs, and provides a structure for mounting the printhead assembly to a printer unit. The printhead module 3030, which is received within a channel 3021 of the casing 3020 so as to be removable therefrom, includes a fluid channel member 3040 which carries printhead tiles 3050 having printhead integrated circuits 3051 incorporating printing nozzles thereon. The printhead assembly 3010 further includes an end housing 3120 and plate 3110 assembly and an end plate 3111 which are attached to longitudinal ends of the assembled casing 3020 and printhead module 3030.
The printhead module 3030 and its associated components will now be described with reference to FIGS. 21 to 34B.
As shown in FIG. 23, the printhead module 3030 includes the fluid channel member 3040 and the printhead tiles 3050 mounted on the upper surface of the member 3040.
As illustrated in FIGS. 21 and 22, sixteen printhead tiles 3050 are provided in the printhead module 3030. However, as will be understood from the following description, the number of printhead tiles and printhead integrated circuits mounted thereon may be varied to meet specific applications of the present invention.
As illustrated in FIGS. 21 and 22, each of the printhead tiles 3050 has a stepped end region so that, when adjacent printhead tiles 3050 are butted together end-to-end, the printhead integrated circuits 3051 mounted thereon overlap in this region. Further, the printhead integrated circuits 3051 extend at an angle relative to the longitudinal direction of the printhead tiles 3050 to facilitate overlapping between the printhead integrated circuits 3051. This overlapping of adjacent printhead integrated circuits 3051 provides for a constant pitch between the printing nozzles (described later) incorporated in the printhead integrated circuits 3051 and this arrangement obviated discontinuities in information printed across or along the print media (not shown) passing the printhead assembly 3010.
FIG. 24 shows the fluid channel member 3040 of the printhead module 3030 which serves as a support member for the printhead tiles 3050. The fluid channel member 3040 is configured so as to fit within the channel 3021 of the casing 3020 and is used to deliver printing ink and other fluids to the printhead tiles 3050. To achieve this, the fluid channel member 3040 includes channel-shaped ducts 3041 which extend throughout its length from each end of the fluid channel member 3040. The channel-shaped ducts 3041 are used to transport printing ink and other fluids from a fluid supply unit (of a printing system to which the printhead assembly 3010 is mounted) to the printhead tiles 3050 via a plurality of outlet ports 3042.
The fluid channel member 3040 is formed by injection moulding a suitable material. Suitable materials are those which have a low coefficient of linear thermal expansion (CTE), so that the nozzles of the printhead integrated circuits are accurately maintained under operational condition (described in more detail later), and have chemical inertness to the inks and other fluids channelled through the fluid channel member 3040. One example of a suitable material is a liquid crystal polymer (LCP). The injection moulding process is employed to form a body portion 3044a having open channels or grooves therein and a lid portion 3044b which is shaped with elongate ridge portions 3044c to be received in the open channels. The body and lid portions 3044a and 3044b are then adhered together with an epoxy to form the channel-shaped ducts 3041 as shown in FIGS. 23 and 24A. However, alternative moulding techniques may be employed to form the fluid channel member 3040 in one piece with the channel-shaped ducts 3041 therein.
The plurality of ducts 3041, provided in communication with the corresponding outlet ports 3042 for each printhead tile 3050, are used to transport different coloured or types of inks and the other fluids. The different inks can have different colour pigments, for example, black, cyan, magenta and yellow, etc., and/or be selected for different printing applications, for example, as visually opaque inks, infrared opaque inks, etc. Further, the other fluids which can be used are, for example, air for maintaining the printhead integrated circuits 3051 free from dust and other impurities and/or for preventing the print media from coming into direct contact with the printing nozzles provided on the printhead integrated circuits 3051, and fixative for fixing the ink substantially immediately after being printed onto the print media, particularly in the case of high-speed printing applications.
In the assembly shown in FIG. 24, seven ducts 3041 are shown for transporting black, cyan, magenta and yellow coloured ink, each in one duct, infrared ink in one duct, air in one duct and fixative in one duct. Even though seven ducts are shown, a greater or lesser number may be provided to meet specific applications. For example, additional ducts might be provided for transporting black ink due to the generally higher percentage of black and white or greyscale printing applications.
The fluid channel member 3040 further includes a pair of longitudinally extending tabs 3043 along the sides thereof for securing the printhead module 3030 to the channel 3021 of the casing 3020 (described in more detail later). It is to be understood however that a series of individual tabs could alternatively be used for this purpose.
As shown in FIG. 25A, each of the printhead tiles 3050 of the printhead module 3030 carries one of the printhead integrated circuits 3051, the latter being electrically connected to a printed circuit board (PCB) 3052 using appropriate contact methods such as wire bonding, with the connections being protectively encapsulated in an epoxy encapsulant 3053. The PCB 3052 extends to an edge of the printhead tile 3050, in the direction away from where the printhead integrated circuits 3051 are placed, where the PCB 3052 is directly connected to a flexible printed circuit board (flex PCB) 3080 for providing power and data to the printhead integrated circuit 3051 (described in more detail later). This is shown in FIG. 26 with individual flex PCBs 3080 extending or “hanging” from the edge of each of the printhead tiles 3050. The flex PCBs 3080 provide electrical connection between the printhead integrated circuits 3051, a power supply 3070 and a PCB 3090 (see FIG. 23) with drive electronics 3100 (see FIG. 38A) housed within the casing 3020 (described in more detail later).
FIG. 25B shows the underside of one of the printhead tiles 3050. A plurality of inlet ports 3054 is provided and the inlet ports 3054 are arranged to communicate with corresponding ones of the plurality of outlet ports 3042 of the ducts 3041 of the fluid channel member 3040 when the printhead tiles 3050 are mounted thereon. That is, as illustrated, seven inlet ports 3054 are provided for the outlet ports 3042 of the seven ducts 3041. Specifically, both the inlet and outlet ports are orientated in an inclined disposition with respect to the longitudinal direction of the printhead module so that the correct fluid, i.e., the fluid being channelled by a specific duct, is delivered to the correct nozzles (typically a group of nozzles is used for each type of ink or fluid) of the printhead integrated circuits.
On a typical printhead integrated circuit 3051 as employed in realisation of the present invention, more than 7000 (e.g., 7680) individual printing nozzles may be provided, which are spaced so as to effect printing with a resolution of 1600 dots per inch (dpi). This is achieved by having a nozzle density of 391 nozzles/mm2 across a print surface width of 20 mm (0.8 in), with each nozzle capable of delivering a drop volume of 1 pl.
Accordingly, the nozzles are micro-sized (i.e., of the order of 10−6 metres) and as such are not capable of receiving a macro-sized (i.e., millimetric) flows of ink and other fluid as presented by the inlet ports 3054 on the underside of the printhead tile 3050. Each printhead tile 3050, therefore, is formed as a fluid distribution stack 3500 (see FIG. 63), which includes a plurality of laminated layers, with the printhead integrated circuit 3051, the PCB 3052, and the epoxy 3053 provided thereon.
The stack 3500 carries the ink and other fluids from the ducts 3041 of the fluid channel member 3040 to the individual nozzles of the printhead integrated circuit 3051 by reducing the macro-sized flow diameter at the inlet ports 3054 to a micro-sized flow diameter at the nozzles of the printhead integrated circuits 3051. An exemplary structure of the stack which provides this reduction is described in more detail later.
Nozzle systems which are applicable to the printhead assembly of the present invention may comprise any type of ink jet nozzle arrangement which can be integrated on a printhead integrated circuit. That is, systems such as a continuous ink system, an electrostatic system and a drop-on-demand system, including thermal and piezoelectric types, may be used.
There are various types of known thermal drop-on-demand system which may be employed which typically include ink reservoirs adjacent the nozzles and heater elements in thermal contact therewith. The heater elements heat the ink and create gas bubbles which generate pressures in the ink to cause droplets to be ejected through the nozzles onto the print media. The amount of ink ejected onto the print media and the timing of ejection by each nozzle are controlled by drive electronics. Such thermal systems impose limitations on the type of ink that can be used however, since the ink must be resistant to heat.
There are various types of known piezoelectric drop-on-demand system which may be employed which typically use piezo-crystals (located adjacent the ink reservoirs) which are caused to flex when an electric current flows therethrough. This flexing causes droplets of ink to be ejected from the nozzles in a similar manner to the thermal systems described above. In such piezoelectric systems the ink does not have to be heated and cooled between cycles, thus providing for a greater range of available ink types. Piezoelectric systems are difficult to integrate into drive integrated circuits and typically require a large number of connections between the drivers and the nozzle actuators.
As an alternative, a micro-electromechanical system (MEMS) of nozzles may be used, such a system including thermo-actuators which cause the nozzles to eject ink droplets. An exemplary MEMS nozzle system applicable to the printhead assembly of the present invention is described in more detail later.
Returning to the assembly of the fluid channel member 3040 and printhead tiles 3050, each printhead tile 3050 is attached to the fluid channel member 3040 such that the individual outlet ports 3042 and their corresponding inlet ports 3054 are aligned to allow effective transfer of fluid therebetween. An adhesive, such as a curable resin (e.g., an epoxy resin), is used for attaching the printhead tiles 3050 to the fluid channel member 3040 with the upper surface of the fluid channel member 3040 being prepared in the manner shown in FIG. 27.
That is, a curable resin is provided around each of the outlet ports 3042 to form a gasket member 3060 upon curing. This gasket member 3060 provides an adhesive seal between the fluid channel member 3040 and printhead tile 3050 whilst also providing a seal around each of the communicating outlet ports 3042 and inlet ports 3054. This sealing arrangement facilitates the flow and containment of fluid between the ports. Further, two curable resin deposits 3061 are provided on either side of the gasket member 3060 in a symmetrical manner.
The symmetrically placed deposits 3061 act as locators for positioning the printhead tiles 3050 on the fluid channel member 3040 and for preventing twisting of the printhead tiles 3050 in relation to the fluid channel member 3040. In order to provide additional bonding strength, particularly prior to and during curing of the gasket members 3060 and locators 3061, adhesive drops 3062 are provided in free areas of the upper surface of the fluid channel member 3040. A fast acting adhesive, such as cyanoacrylate or the like, is deposited to form the locators 3061 and prevents any movement of the printhead tiles 3050 with respect to the fluid channel member 3040 during curing of the curable resin.
With this arrangement, if a printhead tile is to be replaced, should one or a number of nozzles of the associated printhead integrated circuit fail, the individual printhead tiles may easily be removed. Thus, the surfaces of the fluid channel member and the printhead tiles are treated in a manner to ensure that the epoxy remains attached to the printhead tile, and not the fluid channel member surface, if a printhead tile is removed from the surface of the fluid channel member by levering. Consequently, a clean surface is left behind by the removed printhead tile, so that new epoxy can readily be provided on the fluid channel member surface for secure placement of a new printhead tile.
The above-described printhead module of the present invention is capable of being constructed in various lengths, accommodating varying numbers of printhead tiles attached to the fluid channel member, depending upon the specific application for which the printhead assembly is to be employed. For example, in order to provide a printhead assembly for A3-sized pagewidth printing in landscape orientation, the printhead assembly may require 16 individual printhead tiles. This may be achieved by providing, for example, four printhead modules each having four printhead tiles, or two printhead modules each having eight printhead tiles, or one printhead module having 16 printhead tiles (as in FIGS. 21 and 22) or any other suitable combination. Basically, a selected number of standard printhead modules may be combined in order to achieve the necessary width required for a specific printing application.
In order to provide this modularity in an easy and efficient manner, plural fluid channel members of each of the printhead modules are formed so as to be modular and are configured to permit the connection of a number of fluid channel members in an end-to-end manner. Advantageously, an easy and convenient means of connection can be provided by configuring each of the fluid channel members to have complementary end portions. In one embodiment of the present invention each fluid channel member 3040 has a “female” end portion 3045, as shown in FIG. 28, and a complementary “male” end portion 3046, as shown in FIG. 29.
The end portions 3045 and 3046 are configured so that on bringing the male end portion 3046 of one printhead module 3030 into contact with the female end portion 3045 of a second printhead module 3030, the two printhead modules 3030 are connected with the corresponding ducts 3041 thereof in fluid communication. This allows fluid to flow between the connected printhead modules 3030 without interruption, so that fluid such as ink, is correctly and effectively delivered to the printhead integrated circuits 3051 of each of the printhead modules 3030.
In order to ensure that the mating of the female and male end portions 3045 and 3046 provides an effective seal between the individual printhead modules 3030 a sealing adhesive, such as epoxy, is applied between the mated end portions.
It is clear that, by providing such a configuration, any number of printhead modules can suitably be connected in such an end-to-end fashion to provide the desired scale-up of the total printhead length. Those skilled in the art can appreciate that other configurations and methods for connecting the printhead assembly modules together so as to be in fluid communication are within the scope of the present invention.
Further, this exemplary configuration of the end portions 3045 and 3046 of the fluid channel member 3040 of the printhead modules 3030 also enables easy connection to the fluid supply of the printing system to which the printhead assembly is mounted. That is, in one embodiment of the present invention, fluid delivery connectors 3047 and 3048 are provided, as shown in FIGS. 30 and 31, which act as an interface for fluid flow between the ducts 3041 of the printhead modules 3030 and (internal) fluid delivery tubes 3006, as shown in FIG. 32. The fluid delivery tubes 3006 are referred to as being internal since, as described in more detail later, these tubes 3006 are housed in the printhead assembly 3010 for connection to external fluid delivery tubes of the fluid supply of the printing system. However, such an arrangement is clearly only one of the possible ways in which the inks and other fluids can be supplied to the printhead assembly of the present invention.
As shown in FIG. 30, the fluid delivery connector 3047 has a female connecting portion 3047a which can mate with the male end portion 3046 of the printhead module 3030. Alternatively, or additionally, as shown in FIG. 31, the fluid delivery connector 3048 has a male connecting portion 3048a which can mate with the female end portion 3045 of the printhead module 3030. Further, the fluid delivery connectors 3047 and 3048 include tubular portions 3047b and 3048b, respectively, which can mate with the internal fluid delivery tubes 3006. The particular manner in which the tubular portions 3047b and 3048b are configured so as to be in fluid communication with a corresponding duct 3041 is shown in FIG. 32.
As shown in FIGS. 30 to 33, seven tubular portions 3047b and 3048b are provided to correspond to the seven ducts 3041 provided in accordance with the above-described exemplary embodiment of the present invention. Accordingly, seven internal fluid delivery tubes 3006 are used each for delivering one of the seven aforementioned fluids of black, cyan, magenta and yellow ink, IR ink, fixative and air. However, as previously stated, those skilled in the art clearly understand that more or less fluids may be used in different applications, and consequently more or less fluid delivery tubes, tubular portions of the fluid delivery connectors and ducts may be provided.
Further, this exemplary configuration of the end portions of the fluid channel member 3040 of the printhead modules 3030 also enables easy sealing of the ducts 3041. To this end, in one embodiment of the present invention, a sealing member 3049 is provided as shown in FIG. 34A, which can seal or cap both of the end portions of the printhead module 3030. That is, the sealing member 3049 includes a female connecting section 3049a and a male connecting section 3049b which can respectively mate with the male end portion 3046 and the female end portion 3045 of the printhead modules 3030. Thus, a single sealing member is advantageously provided despite the differently configured end portions of a printhead module. FIG. 34B illustrates an exemplary arrangement of the sealing member 3049 sealing the ducts 3041 of the fluid channel member 3040. Sealing of the sealing member 3049 and the fluid channel member 3040 interface is further facilitated by applying a sealing adhesive, such as an epoxy, as described above.
In operation of a single printhead module 3030 for an A4-sized pagewidth printing application, for example, a combination of one of the fluid delivery connectors 3047 and 3048 connected to one corresponding end portion 3045 and 3046 and a sealing member 3049 connected to the other of the corresponding end portions 3045 and 3046 is used so as to deliver fluid to the printhead integrated circuits 3051. On the other hand, in applications where the printhead assembly is particularly long, being comprised of a plurality of printhead modules 3030 connected together (e.g., in wide format printing), it may be necessary to provide fluid from both ends of the printhead assembly. Accordingly, one each of the fluid delivery connectors 3047 and 3048 may be connected to the corresponding end portions 3045 and 3046 of the end printhead modules 3030.
The above-described exemplary configuration of the end portions of the printhead module of the present invention provides, in part, for the modularity of the printhead modules. This modularity makes it possible to manufacture the fluid channel members of the printhead modules in a standard length relating to the minimum length application of the printhead assembly. The printhead assembly length can then be scaled-up by combining a number of printhead modules to form a printhead assembly of a desired length. For example, a standard length printhead module could be manufactured to contain eight printhead tiles, which may be the minimum requirement for A4-sized printing applications. Thus, for a printing application requiring a wider printhead having a length equivalent to 32 printhead tiles, four of these standard length printhead modules could be used. On the other hand, a number of different standard length printhead modules might be manufactured, which can be used in combination for applications requiring variable length printheads.
However, these are merely examples of how the modularity of the printhead assembly of the present invention functions, and other combinations and standard lengths could be employed and fall within the scope of the present invention.
Casing
The casing 3020 and its associated components will now be described with reference to FIGS. 21 to 23 and 35A to 48.
In one embodiment of the present invention, the casing 3020 is formed as a two-piece outer housing which houses the various components of the printhead assembly and provides structure for the printhead assembly which enables the entire unit to be readily mounted in a printing system. As shown in FIG. 23, the outer housing is composed of a support frame 3022 and a cover portion 3023. Each of these portions 3022 and 3023 are made from a suitable material which is lightweight and durable, and which can easily be extruded to form various lengths. Accordingly, in one embodiment of the present invention, the portions 3022 and 3023 are formed from a metal such as aluminium.
As shown in FIGS. 35A to 35C, the support frame 3022 of the casing 3020 has an outer frame wall 3024 and an inner frame wall 3025 (with respect to the outward and inward directions of the printhead assembly 3010), with these two walls being separated by an internal cavity 3026. The channel 3021 (also see FIG. 23) is formed as an extension of an upper wall 3027 of the support frame 3022 and an arm portion 3028 is formed on a lower region of the support frame 3022, extending from the inner frame wall 3025 in a direction away from the outer frame wall 3024. The channel 3021 extends along the length of the support frame 3022 and is configured to receive the printhead module 3030. The printhead module 3030 is received in the channel 3021 with the printhead integrated circuits 3051 facing in an upward direction, as shown in FIGS. 21 to 23, and this upper printhead integrated circuit surface defines the printing surface of the printhead assembly 3010.
As depicted in FIG. 35A, the channel 3021 is formed by the upper wall 3027 and two, generally parallel side walls 3024a and 3029 of the support frame 3022, which are arranged as outer and inner side walls (with respect to the outward and inward directions of the printhead assembly 3010) extending along the length of the support frame 3022. The two side walls 3024a and 3029 have different heights with the taller, outer side wall 3024a being defined as the upper portion of the outer frame wall 3024 which extends above the upper wall 3027 of the support frame 3022, and the shorter, inner side wall 3029 being provided as an upward extension of the upper wall 3027 substantially parallel to the inner frame wall 3025. The outer side wall 3024a includes a recess (groove) 24b formed along the length thereof A bottom surface 3024c of the recess 3024b is positioned so as to be at the same height as a top surface 3029a of the inner side wall 3029 with respect to the upper wall 3027 of the channel 3021. The recess 3024b further has an upper surface 3024d which is formed as a ridge which runs along the length of the outer side wall 3024a (see FIG. 35B).
In this arrangement, one of the longitudinally extending tabs 3043 of the fluid channel member 3040 of the printhead module 3030 is received within the recess 3024b of the outer side wall 3024a so as to be held between the lower and upper surfaces 3024c and 3024d thereof. Further, the other longitudinally extending tab 3043 provided on the opposite side of the fluid channel member 3040, is positioned on the top surface 3029a of the inner side wall 3029. In this manner, the assembled printhead module 3030 may be secured in place on the casing 3020, as will be described in more detail later.
Further, the outer side wall 3024a also includes a slanted portion 3024e along the top margin thereof, the slanted portion 3024e being provided for fixing a print media guide 3005 to the printhead assembly 3010, as shown in FIG. 23. This print media guide is fixed following assembly of the printhead assembly and is configured to assist in guiding print media, such as paper, across the printhead integrated circuits for printing without making direct contact with the nozzles of the printhead integrated circuits.
As shown in FIG. 35A, the upper wall 3027 of the support frame 3022 and the arm portion 3028 include lugs 3027a and 3028a, respectively, which extend along the length of the support frame 3022 (see FIGS. 35B and 35C). The lugs 3027a and 3028a are positioned substantially to oppose each other with respect to the inner frame wall 3025 of the support frame 3022 and are used to secure a PCB support 3091 (described below) to the support frame 3022.
FIGS. 35B and 35C illustrate the manner in which the outer and inner frame walls 3024 and 25 extend for the length of the casing 3020, as do the channel 3021, the upper wall 3027, and its lug 3027a, the outer and inner side walls 3024a and 3029, the recess 3024b and its bottom and upper surfaces 3024c and 3024d, the slanted portion 3024e, the top surface 3029a of the inner side wall 3029, and the arm portion 3028, and its lugs 3028a and 3028b and recessed and curved end portions 3028c and 3028d (described in more detail later).
The PCB support 3091 will now be described with reference to FIGS. 23 and 36 to 42E. In FIG. 23, the support 3091 is shown in its secured position extending along the inner frame wall 3025 of the support frame 3022 from the upper wall 3027 to the arm portion 3028. The support 3091 is used to carry the PCB 3090 which mounts the drive electronics 3100 (as described in more detail later).
As can be seen particularly in FIGS. 37A to 37C, the support 3091 includes lugs 3092 on upper and lower surfaces thereof which communicate with the lugs 3027a and 3028a for securing the support 3091 against the inner frame wall 3025 of the support frame 3022. A base portion 3093 of the support 3091, is arranged to extend along the arm portion 3028 of the support frame 3022, and is seated on the top surfaces of the lugs 3028a and 3028b of the arm portion 3028 (see FIG. 35B) when mounted on the support frame 3022.
The support 3091 is formed so as to locate within the casing 3020 and against the inner frame wall 3025 of the support frame 3022. This can be achieved by moulding the support 3091 from a plastics material having inherent resilient properties to engage with the inner frame wall 3025. This also provides the support 3091 with the necessary insulating properties for carrying the PCB 3090. For example, polybutylene terephthalate (PBT) or polycarbonate may be used for the support 3091.
The base portion 3093 further includes recessed portions 3093a and corresponding locating lugs 3093b, which are used to secure the PCB 3090 to the support 3091 (as described in more detail later). Further, the upper portion of the support 3091 includes upwardly extending arm portions 3094, which are arranged and shaped so as to fit over the inner side wall 3029 of the channel 3021 and the longitudinally extending tab 3043 of the printhead module 3030 (which is positioned on the top surface 3029a of the inner side wall 3029) once the fluid channel member 3040 of the printhead module 3030 has been inserted into the channel 3021. This arrangement provides for securement of the printhead module 3030 within the channel 3021 of the casing 3020, as is shown more clearly in FIG. 23.
In one embodiment of the present invention, the extending arm portions 3094 of the support 3091 are configured so as to perform a “clipping” or “clamping” action over and along one edge of the printhead module 3030, which aids in preventing the printhead module 3030 from being dislodged or displaced from the fully assembled printhead assembly 3010. This is because the clipping action acts upon the fluid channel member 3040 of the printhead module 3030 in a manner which substantially constrains the printhead module 3030 from moving upwards from the printhead assembly 3010 (i.e., in the z-axis direction as depicted in FIG. 23) due to both longitudinally extending tabs 3043 of the fluid channel member 3040 being held firmly in place (in a manner which will be described in more detail below), and from moving across the longitudinal direction of the printhead module 3030 (i.e., in the y-axis direction as depicted in FIG. 23), which will be also described in more detail below.
In this regard, the fluid channel member 3040 of the printhead module 3030 is exposed to a force exerted by the support 3091 directed along the y-axis in a direction from the inner side wall 3029 to the outer side wall 3024a. This force causes the longitudinally extending tab 3043 of the fluid channel member 3040 on the outer side wall 3024a side of the support frame 3022 to be held between the lower and upper surfaces 3024c and 3024d of the recess 3024b. This force, in combination with the other longitudinally extending tab 3043 of the fluid channel member 3040 being held between the top surface 3029a of the inner side wall 3029 and the extending arm portions 3094 of the support 3091, acts to inhibit movement of the printhead module 3030 in the z-axis direction (as described in more detail later).
However, the printhead module 3030 is still able to accommodate movement in the x-axis direction (i.e., along the longitudinal direction of the printhead module 3030), which is desirable in the event that the casing 3020 undergoes thermal expansion and contraction, during operation of the printing system. As the casing is typically made from an extruded metal, such as aluminium, it may undergo dimensional changes due to such materials being susceptible to thermal expansion and contraction in a thermally variable environment, such as is present in a printing unit.
That is, in order to ensure the integrity and reliability of the printhead assembly, the fluid channel member 3040 of the printhead module 3030 is firstly formed of material (such as LCP or the like) which will not experience substantial dimensional changes due to environmental changes thereby retaining the positional relationship between the individual printhead tiles, and the printhead module 3030 is arranged to be substantially independent positionally with respect to the casing 3020 (i.e., the printhead module “floats” in the longitudinal direction of the channel 3021 of the casing 3020) in which the printhead module 3030 is removably mounted.
Therefore, as the printhead module is not constrained in the x-axis direction, any thermal expansion forces from the casing in this direction will not be transferred to the printhead module. Further, as the constraint in the z-axis and y-axis directions is resilient, there is some tolerance for movement in these directions. Consequently, the delicate printhead integrated circuits of the printhead modules are protected from these forces and the reliability of the printhead assembly is maintained.
Furthermore, the clipping arrangement also allows for easy assembly and disassembly of the printhead assembly by the mere “unclipping” of the PCB support(s) from the casing. In the exemplary embodiment shown in FIG. 36, a pair of extending arm portions 3094 is provided; however those skilled in the art will understand that a greater or lesser number is within the scope of the present invention.
Referring again to FIGS. 36 to 37C, the support 3091 further includes a channel portion 3095 in the upper portion thereof. In the exemplary embodiment illustrated, the channel portion 3095 includes three channelled recesses 3095a, 3095b and 3095c. The channelled recesses 3095a, 3095b and 3095c are provided so as to accommodate three longitudinally extending electrical conductors or busbars 3071, 3072 and 3073 (see FIG. 22) which form the power supply 3070 (see FIG. 23) and which extend along the length of the printhead assembly 3010. The busbars 3071, 3072 and 3073 are conductors which carry the power required to operate the printhead integrated circuits 3051 and the drive electronics 3100 located on the PCB 3090 (shown in FIG. 38A and described in more detail later), and may be formed of copper with gold plating, for example.
In one embodiment of the present invention, three busbars are used in order to provide for voltages of Vcc (e.g., via the busbar 3071), ground (Gnd) (e.g., via the busbar 3072) and V+ (e.g., via the busbar 3073). Specifically, the voltages of Vcc and Gnd are applied to the drive electronics 3100 and associated circuitry of the PCB 3090, and the voltages of Vcc, Gnd and V+ are applied to the printhead integrated circuits 3051 of the printhead tiles 3050. It will be understood by those skilled in the art that a greater or lesser number of busbars, and therefore channelled recesses in the PCB support can be used depending on the power requirements of the specific printing applications.
The support 3091 of the present invention further includes (lower) retaining clips 3096 positioned below the channel portion 3095. In the exemplary embodiment illustrated in FIG. 36, a pair of the retaining clips 3096 is provided. The retaining clips 3096 include a notch portion 3096a on a bottom surface thereof which serves to assist in securely mounting the PCB 3090 on the support 3091. To this end, as shown in the exemplary embodiment of FIG. 38A, the PCB 3090 includes a pair of slots 3097 in a topmost side thereof (with respect to the mounting direction of the PCB 3090), which align with the notch portions 3096a when mounted so as to facilitate engagement with the retaining clips 3096.
As shown in FIG. 23, the PCB 3090 is snugly mounted between the notch portions 3096a of the retaining clips 3096 and the afore-mentioned recessed portions 3093a and locating lugs 3093b of the base portion 3093 of the support 3091. This arrangement securely holds the PCB 3090 in position so as to enable reliable connection between the drive electronics 3100 of the PCB 3090 and the printhead integrated circuits 3051 of the printhead module 3030.
Referring again to FIG. 38A, an exemplary circuit arrangement of the PCB 3090 will now be described. The circuitry includes the drive electronics 3100 in the form of a print engine controller (PEC) integrated circuit. The PEC integrated circuit 3100 is used to drive the printhead integrated circuits 3051 of the printhead module 3030 in order to print information on the print media passing the printhead assembly 3010 when mounted to a printing unit. The functions and structure of the PEC integrated circuit 3100 are discussed in more detail later.
The exemplary circuitry of the PCB 3090 also includes four connectors 3098 in the upper portion thereof (see FIG. 38B) which receive lower connecting portions 3081 of the flex PCBs 3080 that extend from each of the printhead tiles 3050 (see FIG. 26). Specifically, the corresponding ends of four of the flex PCBs 3080 are connected between the PCBs 3052 of four printhead tiles 3050 and the four connectors 3098 of the PCB 3090. In turn, the connectors 3098 are connected to the PEC integrated circuit 3100 so that data communication can take place between the PEC integrated circuit 3100 and the printhead integrated circuits 3051 of the four printhead tiles 3050.
In the above-described embodiment, one PEC integrated circuit is chosen to control four printhead tiles in order to satisfy the necessary printing speed requirements of the printhead assembly. In this manner, for a printhead assembly having 16 printhead tiles, as described above with respect to FIGS. 21 and 22, four PEC integrated circuits are required and therefore four PCB supports 3091 are used. However, it will be understood by those skilled in the art that the number of PEC integrated circuits used to control a number of printhead tiles may be varied, and as such many different combinations of the number of printhead tiles, PEC integrated circuits, PCBs and PCB supports that may be employed depending on the specific application of the printhead assembly of the present invention. Further, a single PEC integrated circuit 3100 could be provided to drive a single printhead integrated circuit 3051. Furthermore, more than one PEC integrated circuit 3100 may be placed on a PCB 3090, such that differently configured PCBs 3090 and supports 3091 may be used.
It is to be noted that the modular approach of employing a number of PCBs holding separate PEC integrated circuits for controlling separate areas of the printhead advantageously assists in the easy determination, removal and replacement of defective circuitry in the printhead assembly.
The above-mentioned power supply to the circuitry of the PCB 3090 and the printhead integrated circuits 3051 mounted to the printhead tiles 3050 is provided by the flex PCBs 3080. Specifically, the flex PCBs 3080 are used for the two functions of providing data connection between the PEC integrated circuit(s) 3100 and the printhead integrated circuits 3051 and providing power connection between the busbars 3071, 3072 and 3073 and the PCB 3090 and the printhead integrated circuits 3051. In order to provide the necessary electrical connections, the flex PCBs 3080 are arranged to extend from the printhead tiles 3050 to the PCB 3090. This may be achieved by employing the arrangement shown in FIG. 23, in which a resilient pressure plate 3074 is provided to urge the flex PCBs 3080 against the busbars 3071, 3072 and 3073. In this arrangement, suitably arranged electrical connections are provided on the flex PCBs 3080 which route power from the busbars 3071 and 3072 (i.e., Vcc and Gnd) to the connectors 3098 of the PCB 3090 and power from all of the busbars 3071, 3072 and 3073 (i.e., Vcc, Gnd and V+) to the PCB 3052 of the printhead tiles 3050.
The pressure plate 3074 is shown in more detail in FIGS. 39A to 41. The pressure plate 3074 includes a raised portion (pressure elastomer) 3075 which is positioned on a rear surface of the pressure plate 3074 (with respect to the mounting direction on the support 3091), as shown in FIG. 39B, so as to be aligned with the busbars 3071, 3072 and 3073, with the flex PCBs 3080 lying therebetween when the pressure plate 3074 is mounted on the support 3091. The pressure plate 3074 is mounted to the support 3091 by engaging holes 3074a with corresponding ones of (upper) retaining clips 3099 of the support 3091 which project from the extending arm portions 3094 (see FIG. 35A) and holes 3074b with the corresponding ones of the (lower) retaining clips 3096, via tab portions 3074c thereof (see FIG. 40). The pressure plate 3074 is formed so as to have a spring-like resilience which urges the flex PCBs 3080 into electrical contact with the busbars 3071, 3072 and 3073 with the raised portion 3075 providing insulation between the pressure plate 3074 and the flex PCBs 3080.
As shown most clearly in FIG. 41, the pressure plate 3074 further includes a curved lower portion 3074d which serves as a means of assisting the demounting of the pressure plate 3074 from the support 3091.
The specific manner in which the pressure plate 3074 is retained on the support 3091 so as to urge the flex PCBs 3080 against the busbars 3071, 3072 and 3073, and the manner in which the extending arm portions 3094 of the support 3091 enable the above-mentioned clipping action will now be fully described with reference to FIGS. 42 and 42A to 42E.
FIG. 42 illustrates a front schematic view of the support 3091 in accordance with a exemplary embodiment of the present invention. FIG. 42A is a side sectional view taken along the line I-I in FIG. 42 with the hatched sections illustrating the components of the support 3091 situated on the line I-I.
FIG. 42A particularly shows one of the upper retaining clips 3099. An enlarged view of this retaining clip 3099 is shown in FIG. 42B. The retaining clip 3099 is configured so that an upper surface of one of the holes 3074a of the pressure plate 3074 can be retained against an upper surface 3099a and a retaining portion 3099b of the retaining clip 3099 (see FIG. 41). Due to the spring-like resilience of the pressure plate 3074, the upper surface 3099a exerts a slight upwardly and outwardly directed force on the pressure plate 3074 when the pressure plate 3074 is mounted thereon so as to cause the upper part of the pressure plate 3074 to abut against the retaining portion 3099b. 
Referring now to FIG. 42C, which is a side sectional view taken along the line II-II in FIG. 42, one of the lower retaining clips 3096 is illustrated. An enlarged view of this retaining clip 3096 is shown in FIG. 42D. The retaining clip 3096 is configured so that a tab portion 3074c of one of the holes 3074b of the pressure plate 3074 can be retained against an inner surface 3096c of the retaining clip 3096 (see FIG. 40). Accordingly, due to the above-described slight force exerted by the retaining clip 3099 on the upper part of the pressure plate 3074 in a direction away from the support 3091, the lower part of the pressure plate 3074 is loaded towards the opposite direction, e.g., in an inward direction with respect to the support frame 3022. Consequently, the pressure plate 3074 is urged towards the busbars 3071, 3072 and 3073, which in turn serves to urge the flex PCBs 3080 in the same direction via the raised portion 3075, so as to effect reliable contact with the busbars 3071, 3072 and 3073.
Returning to FIG. 42C, in which one of the extending arm portions 3094 is illustrated. An enlarged view of this extending arm portion 3094 is shown in FIG. 42E. The extending arm portion 3094 is configured so as to be substantially L-shaped, with the foot section of the L-shape located so as to fit over the inner side wall 3029 of the channel 3021 and the longitudinally extending tab 3043 of the fluid channel member 3040 of the printhead module 3030 arranged thereon. As shown in FIG. 42E, the end of the foot section of the L-shape has an arced surface. This surface corresponds to the edge of a recessed portion 3094a provided in each the extending arm portions 3094, the centre of which is positioned substantially at the line II-II in FIG. 42 (see FIGS. 36 and 37C). The recessed portions 3094a are arranged so as to engage with angular lugs 3043a regularly spaced along the length of the longitudinally extending tabs 3043 of the fluid channel member 3040 (FIG. 24A), so as to correspond with the placement of the printhead tiles 3050, when the extending arm portions 3094 are clipped over the fluid channel member 3040.
In this position, the arced edge of the recessed portion 3094a is contacted with the angled surface of the angular lugs 3043a (see FIG. 24A), with this being the only point of contact of the extending arm portion 3094 with the longitudinally extending tab 3043. Although not shown in FIG. 24A, the longitudinally extending tab 3043 on the other side of the fluid channel member 3040 has similarly angled lugs 3043a, where the angled surface comes into contact with the upper surface 3024d of the recess 3024b on the support frame 3022.
As alluded to previously, due to this specific arrangement, at these contact points a downwardly and inwardly directed force is exerted on the fluid channel member 3040 by the extending arm portion 3094. The downwardly directed force assists to constrain the printhead module 3030 in the channel 3021 in the z-axis direction as described earlier. The inwardly directed force also assists in constraining the printhead module 3030 in the channel 3021 by urging the angular lugs 3043a on the opposing longitudinally extending tab 3043 of the fluid channel member 3040 into the recess 3024b of the support frame 3020, where the upper surface 3024d of the recess 3024b also applies an opposing downwardly and inwardly directed force on the fluid channel member. In this regard the opposing forces act to constrain the range of movement of the fluid channel member 3040 in the y-axis direction. It is to be understood that the two angular lugs 3043a shown in FIG. 24A for each of the recessed portions 3094a are merely an exemplary arrangement of the angular lugs 3043a. 
Further, the angular lugs 3043a are positioned so as to correspond to the placement of the printhead tiles 3050 on the upper surface of the fluid channel member 3040 so that, when mounted, the lower connecting portions 3081 of each of the flex PCBs 3080 are aligned with the corresponding connectors 3098 of the PCBs 3090 (see FIGS. 26 and 38B). This is facilitated by the flex PCBs 3080 having a hole 3082 therein (FIG. 26) which is received by the lower retaining clip 3096 of the support 3091. Consequently, the flex PCBs 3080 are correctly positioned under the pressure plate 3074 retained by the retaining clip 3096 as described above.
Further still, as also shown in FIGS. 42C and 42E, the (upper) lug 3092 of the support 3091 has an inner surface 3092a which is also slightly angled from the normal of the plane of the support 3091 in a direction away from the support 3091. As shown in FIGS. 37B and 37C, the upper lugs 3092 are formed as resilient members which are able to hinge with respect to the support 3091 with a spring-like action. Consequently, when mounted to the casing 3020, a slight force is exerted against the lug 3027a of the uppermost face 3027 of the support frame 3022 which assists in securing the support 3091 to the support frame 3022 of the casing 3020 by biasing the (lower) lug 3092 into the recess formed between the lower part of the inner surface 3025 and the lug 3028a of the arm portion 3028 of the support frame 3022.
The manner in which the structure of the casing 3020 is completed in accordance with an exemplary embodiment of the present invention will now be described with reference to FIGS. 21, 22, 35A and 43.
As shown in FIGS. 21 and 22, the casing 3020 includes the aforementioned cover portion 3023 which is positioned adjacent the support frame 3022. Thus, together the support frame 3022 and the cover portion 3023 define the two-piece outer housing of the printhead assembly 3010. The profile of the cover portion 3023 is as shown in FIG. 43.
The cover portion 3023 is configured so as to be placed over the exposed PCB 3090 mounted to the PCB support 3091 which in turn is mounted to the support frame 3022 of the casing 3020, with the channel 3021 thereof holding the printhead module 3030. As a result, the cover portion 3023 encloses the printhead module 3030 within the casing 3020.
The cover portion 3023 includes a longitudinally extending tab 3023a on a bottom surface thereof (with respect to the orientation of the printhead assembly 3010) which is received in the recessed portion 3028c formed between the lug 3028b and the curved end portion 3028d of the arm portion 3028 of the support frame 3022 (see FIG. 35A). This arrangement locates and holds the cover portion 3023 in the casing 3020 with respect to the support frame 3022. The cover portion 3023 is further held in place by affixing the end plate 3111 or the end housing 3120 via the end plate 3110 on the longitudinal side thereof using screws through threaded portions 3023b (see FIGS. 43, 49 and 59). The end plates 3110 and/or 111 are also affixed to the support frame 3022 on either longitudinal side thereof using screws through threaded portions 3022a and 3022b provided in the internal cavity 3026 (see FIGS. 35A, 49 and 59). Further, the cover portion 3023 has the profile as shown in FIG. 33, in which a cavity portion 3023c is arranged at the inner surface of the cover portion 3023 (with respect to the inward direction on the printhead assembly 3010) for accommodating the pressure plate(s) 3074 mounted to the PCB support(s) 91.
Further, the cover portion may also include fin portions 3023d (see also FIG. 23) which are provided for dissipating heat generated by the PEC integrated circuits 3100 during operation thereof To facilitate this the inner surface of the cover portion 3023 may also be provided with a heat coupling material portion (not shown) which physically contacts the PEC integrated circuits 3100 when the cover portion 3023 is attached to the support frame 3022. Further still, the cover portion 3023 may also function to inhibit electromagnetic interference (EMI) which can interfere with the operation of the dedicated electronics of the printhead assembly 3010.
The manner in which a plurality of the PCB supports 3091 are assembled in the support frame 3022 to provide a sufficient number of PEC integrated circuits 3100 per printhead module 3030 in accordance with one embodiment of the present invention will now be described with reference to FIGS. 36 and 44 to 47.
As described earlier, in one embodiment of the present invention, each of the supports 3091 is arranged to hold one of the PEC integrated circuits 3100 which in turn drives four printhead integrated circuits 3051. Accordingly, in a printhead module 3030 having 16 printhead tiles, for example, four PEC integrated circuits 3100, and therefore four supports 3091 are required. For this purpose, the supports 3091 are assembled in an end-to-end manner, as shown in FIG. 44, so as to extend the length of the casing 3020, with each of the supports 3091 being mounted and clipped to the support frame 3022 and printhead module 3030 as previously described. In such a way, the single printhead module 3030 of sixteen printhead tiles 3050 is securely held to the casing 3020 along the length thereof.
As shown more clearly in FIG. 36, the supports 3091 further include raised portions 3091a and recessed portions 3091b at each end thereof. That is, each edge region of the end walls of the supports 3091 include a raised portion 3091a with a recessed portion 3091b formed along the outer edge thereof This configuration produces the abutting arrangement between the adjacent supports 3091 shown in FIG. 44.
This arrangement of two abutting recessed portions 3091b with one raised portion 3091a at either side thereof forms a cavity which is able to receive a suitable electrical connecting member 3102 therein, as shown in cross-section in FIG. 45. Such an arrangement enables adjacent PCBs 3090, carried on the supports 3091 to be electrically connected together so that data signals which are input from either or both ends of the plurality of assembled supports 3091, i.e., via data connectors (described later) provided at the ends of the casing 3020, are routed to the desired PEC integrated circuits 3100, and therefore to the desired printhead integrated circuits 3051.
To this end, the connecting members 3102 provide electrical connection between a plurality of pads provided at edge contacting regions on the underside of each of the PCBs 3090 (with respect to the mounting direction on the supports 3091). Each of these pads is connected to different regions of the circuitry of the PCB 3090. FIG. 46 illustrates the pads of the PCBs as positioned over the connecting member 3102. Specifically, as shown in FIG. 46, the plurality of pads are provided as a series of connection strips 3090a and 3090b in a substantially central region of each edge of the underside of the PCBs 3090.
As mentioned above, the connecting members 3102 are placed in the cavity formed by the abutting recessed portions 3091b of adjacent supports 3091 (see FIG. 45), such that when the PCBs 3090 are mounted on the supports 3091, the connection strips 3090a of one PCB 3090 and the connection strips 3090b of the adjacent PCB 3090 come into contact with the same connecting member 3102 so as to provide electrical connection therebetween.
To achieve this, the connecting members 3102 may each be formed as shown in FIG. 47 to be a rectangular block having a series of conducting strips 3104 provided on each surface thereof. Alternatively, the conducting strips 3104 may be formed on only one surface of the connecting members 3102 as depicted in FIG. 45 and 3046. Such a connecting member may typically be formed of a strip of silicone rubber printed to provide sequentially spaced conductive and non-conductive material strips. A shown in FIG. 47, these conducting strips 3104 are provided in a 2:1 relationship with the connecting strips 3090a and 3090b of the PCBs 3090. That is, twice as many of the conducting strips 3104 are provided than the connecting strips 3090a and 3090b, with the width of the conducting strips 3104 being less than half the width of the connecting strips 3090a and 3090b. Accordingly, any one connecting strip 3090a or 90b may come into contact with one or both of two corresponding conducting strips 3104, thus minimising alignment requirements between the connecting members 3104 and the contacting regions of the PCBs 3090.
In one embodiment of the present invention, the connecting strips 3090a and 3090b are about 0.4 mm wide with a 0.4 mm spacing therebetween, so that two thinner conducting strips 3104 can reliably make contact with only one each of the connecting strips 3090a and 3090b whilst having a sufficient space therebetween to prevent short circuiting. The connecting strips 3090a and 3090b and the conducting strips 3104 may be gold plated so as to provide reliable contact. However, those skilled in the art will understand that use of the connecting members and suitably configured PCB supports is only one exemplary way of connecting the PCBs 3090, and other types of connections are within the scope of the present invention.
Additionally, the circuitry of the PCBs 3090 is arranged so that a PEC integrated circuit 3100 of one of the PCB 3090 of an assembled support 3091 can be used to drive not only the printhead integrated circuits 3051 connected directly to that PCB 3090, but also those of the adjacent PCB(s) 3090, and further of any non-adjacent PCB(s) 3090. Such an arrangement advantageously provides the printhead assembly 3010 with the capability of continuous operation despite one of the PEC integrated circuits 3100 and/or PCBs 3090 becoming defective, albeit at a reduced printing speed.
In accordance with the above-described scalability of the printhead assembly 3010 of the present invention, the end-to-end assembly of the PCB supports 3091 can be extended up to the required length of the printhead assembly 3010 due to the modularity of the supports 3091. For this purpose, the busbars 3071, 3072 and 3073 need to be extended for the combined length of the plurality of PCB supports 3091, which may result in insufficient power being delivered to each of the PCBs 3090 when a relatively long printhead assembly 3010 is desired, such as in wide format printing applications.
In order to minimise power loss, two power supplies can be used, one at each end of the printhead assembly 3010, and a group of busbars 3070 from each end may be employed. The connection of these two busbar groups, e.g., substantially in the centre of the printhead assembly 3010, is facilitated by providing the exemplary connecting regions 3071a, 3072a and 3073a shown in FIG. 48.
Specifically, the busbars 3071, 3072 and 3073 are provided in a staggered arrangement relative to each other and the end regions thereof are configured with the rebated portions shown in FIG. 48 as connecting regions 3071a, 3072a and 3073a. Accordingly, the connecting regions 3071a, 3072a and 3073a of the first group of busbars 3070 overlap and are engaged with the connecting regions 3071a, 3072a and 3073a of the corresponding ones of the busbars 3071, 3072 and 3073 of the second group of busbars 3070.
The manner in which the busbars are connected to the power supply and the arrangements of the end plates 3110 and 111 and the end housing(s) 3120 which house these connections will now be described with reference to FIGS. 21, 22 and 49 to 59.
FIG. 49 illustrates an end portion of an exemplary printhead assembly according to one embodiment of the present invention similar to that shown in FIG. 21. At this end portion, the end housing 3120 is attached to the casing 3020 of the printhead assembly 3010 via the end plate 3110.
The end housing and plate assembly houses connection electronics for the supply of power to the busbars 3071, 3072 and 3073 and the supply of data to the PCBs 3090. The end housing and plate assembly also houses connections for the internal fluid delivery tubes 3006 to external fluid delivery tubes (not shown) of the fluid supply of the printing system to which the printhead assembly 3010 is being applied.
These connections are provided on a connector arrangement 3115 as shown in FIG. 50. FIG. 50 illustrates the connector arrangement 3115 fitted to the end plate 3110 which is attached, via screws as described earlier, to an end of the casing 3020 of the printhead assembly 3010 according to one embodiment of the present invention. As shown, the connector arrangement 3115 includes a power supply connection portion 3116, a data connection portion 3117 and a fluid delivery connection portion 3118. Terminals of the power supply connection portion 3116 are connected to corresponding ones of three contact screws 3116a, 3116b, 3116c provided so as to each connect with a corresponding one of the busbars 3071, 3072 and 3073. To this end, each of the busbars 3071, 3072 and 3073 is provided with threaded holes in suitable locations for engagement with the contact screws 3116a, 3116b, 3116c. Further, the connection regions 3071a, 3072a and 3073a (see FIG. 48) may also be provided at the ends of the busbars 3071, 3072 and 3073 which are to be in contact with the contact screws 3116a, 3116b, 3116c so as to facilitate the engagement of the busbars 3071, 3072 and 3073 with the connector arrangement 3115, as shown in FIG. 51.
In FIGS. 50, 52A and 52B, only three contact screws or places for three contact screws are shown, one for each of the busbars. However, the use of a different number of contact screws is within the scope of the present invention. That is, depending on the amount of power being routed to the busbars, in order to provide sufficient power contact it may be necessary to provide two or more contact screws for each busbar (see, for example, FIGS. 53B and 53C). Further, as mentioned earlier a greater or lesser number of busbars may be used, and therefore a corresponding greater of lesser number of contact screws. Further still, those skilled in the art will understand that other means of contacting the busbars to the power supply via the connector arrangements as are typical in the art, such as soldering, are within the scope of the present invention.
The manner in which the power supply connection portion 3116 and the data connection portion 3117 are attached to the connector arrangement 3115 is shown in FIGS. 52A and 52B. Further, connection tabs 3118a of the fluid delivery connection portion 3118 are attached at holes 3115a of the connector arrangement 3115 so as that the fluid delivery connection portion 3118 overlies the data connection portion 3117 with respect to the connector arrangement 3115 (see FIGS. 50 and 52C).
As seen in FIGS. 50 and 52C, seven internal and external tube connectors 3118b and 118c are provided in the fluid delivery connection portion 3118 in accordance with the seven internal fluid delivery tubes 3006. That is, as shown in FIG. 54, the fluid delivery tubes 3006 connect between the internal tube connectors 3118b of the fluid delivery connection portion 3118 and the seven tubular portions 3047b or 3048b of the fluid delivery connector 3047 or 3048. As stated earlier, those skilled in the art clearly understand that the present invention is not limited to this number of fluid delivery tubes, etc.
Returning to FIGS. 52A and 52B, the connector arrangement 3115 is shaped with regions 3115b and 3115c so as to be received by the casing 3020 in a manner which facilitates connection of the busbars 3071, 3072 and 3073 to the contact screws 3116a, 3116b and 3116c of the power supply connection portion 3116 via region 3115b and connection of the end PCB 3090 of the plurality of PCBs 3090 arranged on the casing 3020 to the data connection portion 3117 via region 3115c. 
The region 3115c of the connector arrangement 3115 is advantageously provided with connection regions (not shown) of the data connection portion 3117 which correspond to the connection strips 3090a or 90b provided at the edge contacting region on the underside of the end PCB 3090, so that one of the connecting members 3102 can be used to connect the data connections of the data connection portion 3117 to the end PCB 3090, and thus all of the plurality of PCBs 3090 via the connecting members 3102 provided therebetween.
This is facilitated by using a support member 3112 as shown in FIG. 53A, which has a raised portion 3112a and a recessed portion 3112b at one edge thereof which is arranged to align with the raised and recessed portions 3091a and 3091b, respectively, of the end PCB support 3091 (see FIG. 44). The support member 3112 is attached to the rear surface of the end PCB support 3091 by engaging a tab 3112c with a slot region 3091c on the rear surface of the end PCB support 3091 (see FIGS. 37B and 37C), and the region 3115c of the connector arrangement 3115 is retained at upper and lower side surfaces thereof by clip portions 3112d of the support member 3112 so as that the connection regions of the region 3115c are in substantially the same plane as the edge contacting regions on the underside of the end PCB 3090.
Thus, when the end plate 3110 is attached to the end of the casing 3020, an abutting arrangement is formed between the recessed portions 3112b and 3091b, similar to the abutting arrangement formed between the recessed portions 3091b of the adjacent supports 3091 of FIG. 44. Accordingly, the connecting member 3102 can be accommodated compactly between the end PCB 3090 and the region 3115c of the connector arrangement 3115. This arrangement is shown in FIGS. 53B and 33C for another type of connector arrangement 3125 with a corresponding region 3125c, which is described in more detail below with respect to FIGS. 57, 58A and 58B.
This exemplary manner of connecting the data connection portion 3117 to the end PCB 3090 contributes to the modular aspect of the present invention, in that it is not necessary to provide differently configured PCBs 3090 to be arranged at the longitudinal ends of the casing 3020 and the same method of data connection can be retained throughout the printhead assembly 3010. It will be understood by those skilled in the art however that the provision of additional or other components to connect the data connection portion 3117 to the end PCB 3090 is also included in the scope of the present invention.
Returning to FIG. 50, it can be seen that the end plate 3110 is shaped so as to conform with the regions 3115b and 3115c of the connector arrangement 3115, such that these regions can project into the casing 3020 for connection to the busbars 3071, 3072 and 3073 and the end PCB 3090, and so that the busbars 3071, 3072 and 3073 can extend to contact screws 3116a, 3116b and 3116c provided on the connector arrangement 3115. This particular shape of the end plate 3110 is shown in FIG. 55A, where regions 3110 and 3110b of the end plate 3110 correspond with the regions 3115b and 3115c of the connector arrangement 3115, respectively. Further, a region 3110c of the end plate 3110 is provided so as to enable connection between the internal fluid delivery tubes 3006 and the fluid delivery connectors 3047 and 3048 of the printhead module 3030.
The end housing 3120 is also shaped as shown in FIG. 55A, so as to retain the power supply, data and fluid delivery connection portions 3116, 3117 and 3118 so that external connection regions thereof, such as the external tube connector 3118c of the fluid delivery connection portion 3118 shown in FIG. 52C, are exposed from the printhead assembly 3010, as shown in FIG. 49.
FIG. 55B illustrates the end plate 3110 and the end housing 3120 which may be provided at the other end of the casing 3020 of the printhead assembly 3010 according to an exemplary embodiment of the present invention. The exemplary embodiment shown in FIG. 55B, for example, corresponds to a situation where an end housing is provided at both ends of the casing so as to provide power supply and/or fluid delivery connections at both ends of the printhead assembly. Such an exemplary printhead assembly is shown in FIG. 56, and corresponds, for example, to the above-mentioned exemplary application of wide format printing, in which the printhead assembly is relatively long.
To this end, FIG. 57 illustrates the end housing and plate assembly for the other end of the casing with the connector arrangement 3125 housed therein. The busbars 3071, 3072 and 3073 are shown attached to the connector arrangement 3125 for illustration purposes. As can be seen, the busbars 3071, 3072 and 3073 are provided with connection regions 3071a, 3072a and 3073a for engagement with connector arrangement 3125, similar to that shown in FIG. 51 for the connector arrangement 3115. The connector arrangement 3125 is illustrated in more detail in FIGS. 58A and 58B.
As can be seen from FIGS. 58A and 58B, like the connector arrangement 3115, the connector arrangement 3125 holds the power supply connection portion 3116 and includes places for contact screws for contact with the busbars 3071, 3072 and 3073, holes 3125a for retaining the clips 3118a of the fluid delivery portion 3118 (not shown), and regions 3125b and 3125c for extension into the casing 3020 through regions 3110 and 3110b of the end plate 3110, respectively. However, unlike the connector arrangement 3115, the connector arrangement 3125 does not hold the data connection portion 3117 and includes in place thereof a spring portion 3125d. 
This is because, unlike the power and fluid supply in a relatively long printhead assembly application, it is only necessary to input the driving data from one end of the printhead assembly. However, in order to input the data signals correctly to the plurality of PEC integrated circuits 3100, it is necessary to terminate the data signals at the end opposite to the data input end. Therefore, the region 3125c of the connector arrangement 3125 is provided with termination regions (not shown) which correspond with the edge contacting regions on the underside of the end PCB 3090 at the terminating end. These termination regions are suitably connected with the contacting regions via a connecting member 3102, in the manner described above.
The purpose of the spring portion 3125d is to maintain these terminal connections even in the event of the casing 3020 expanding and contracting due to temperature variations as described previously, any effect of which may exacerbated in the longer printhead applications. The configuration of the spring portion 3125d shown in FIGS. 58A and 58B, for example, enables the region 3125c to be displaced through a range of distances from a body portion 3125e of the connector arrangement 3125, whilst being biased in a normal direction away from the body portion 3125e. 
Thus, when the connector arrangement 3125 is attached to the end plate 3110, which in turn has been attached to the casing 3020, the region 3125c is brought into abutting contact with the adjacent edge of the end PCB 3090 in such a manner that the spring portion 3125d experiences a pressing force on the body of the connector arrangement 3125, thereby displacing the region 3125c from its rest position toward the body portion 3125e by a predetermined amount. This arrangement ensures that in the event of any dimensional changes of the casing 3020 via thermal expansion and contraction thereof, the data signals remain terminated at the end of the plurality of PCBs 3090 opposite to the end of data signal input as follows.
The PCB supports 3091 are retained on the support frame 3022 of the casing 3020 so as to “float” thereon, similar to the manner in which the printhead module(s) 3030 “float” on the channel 3021 as described earlier. Consequently, since the supports 3091 and the fluid channel members 3040 of the printhead modules 3030 are formed of similar materials, such as LCP or the like, which have the same or similar coefficients of expansion, then in the event of any expansion and contraction of the casing 3020, the supports 3091 retain their relative position with the printhead module(s) 3030 via the clipping of the extending arm portions 3094.
Therefore, each of the supports 3091 retain their adjacent connections via the connecting members 3102, which is facilitated by the relatively large overlap of the connecting members 3102 and the connection strips 3090a and 3090b of the PCBs 3090 as shown in FIG. 47. Accordingly, since the PCBs 3090, and therefore the supports 3091 to which they are mounted, are biased towards the connector arrangement 3115 by the spring portion 3125d of the connector arrangement 3125, then should the casing 3020 expand and contract, any gaps which might otherwise form between the connector arrangements 3115 and 3125 and the end PCBs 3090 are prevented, due to the action of the spring portion 3125d. 
Accommodation for any expansion and contraction is also facilitated with respect to the power supply by the connecting regions 3071a, 3072a and 3073a of the two groups of busbars 3070 which are used in the relatively long printhead assembly application. This is because, these connecting regions 3071a, 3072a and 3073a are configured so that the overlap region between the two groups of busbars 3070 allows for the relative movement of the connector arrangements 3115 and 3125 to which the busbars 3071, 3072 and 3073 are attached whilst maintaining a connecting overlap in this region.
In the examples illustrated in FIGS. 50, 53B, 53C and 57, the end sections of the busbars 3071, 3072 and 3073 are shown connected to the connector arrangements 3115 and 3125 (via the contact screws 3116a, 3116b and 3116c) on the front surface of the connector arrangements 3115 and 3125 (with respect to the direction of mounting to the casing 3020). Alternatively, the busbars 3071, 3072 and 3073 can be connected at the rear surfaces of the connector arrangements 3115 and 3125. In such an alternative arrangement, even though the busbars 3071, 3072 and 3073 thus connected may cause the connector arrangements 3115 and 3125 be slightly displaced toward the cover portion 3023, the regions 3115c and 3125c of the connector arrangements 3115 and 3125 are maintained in substantially the same plane as the edge contacting regions of the end PCBs 3090 due to the clip portions 3112d of the support members 3112 which retain the upper and lower side surfaces of the regions 3115c and 3125c. 
Printed circuit boards having connecting regions printed in discrete areas may be employed as the connector arrangements 3115 and 3125 in order to provide the various above-described electrical connections provided thereby.
FIG. 59 illustrates the end plate 3111 which may be attached to the other end of the casing 3020 of the printhead assembly 3010 according to an exemplary embodiment of the present invention, instead of the end housing and plate assemblies shown in FIGS. 55A and 55B. This provides for a situation where the printhead assembly is not of a length which requires power and fluid to be supplied from both ends. For example, in an A4-sized printing application where a printhead assembly housing one printhead module of 16 printhead tiles may be employed.
In such a situation therefore, since it is unnecessary specifically to provide a connector arrangement at the end of the printhead module 3030 which is capped by the capping member 3049, then the end plate 3111 can be employed which serves to securely hold the support frame 3022 and cover portion 3023 of the casing 3020 together via screws secured to the threaded portions 3022a, 22b and 23b thereof, in the manner already described (see also FIG. 22).
Further, if it is necessary to provide data signal termination at this end of the plurality of PCBs 3090, then the end plate 3111 can be provided with a slot section (not shown) on the inner surface thereof (with respect to the mounting direction on the casing 3020), which can support a PCB (not shown) having termination regions which correspond with the edge contacting regions of the end PCB 3090, similar to the region 3125c of the connector arrangement 3125. Also similarly, these termination regions may be suitably connected with the contacting regions via a support member 3112 and a connecting member 3102. This PCB may also include a spring portion between the termination regions and the end plate 3111, similar to the spring portion 3125d of the connector arrangement 3125, in case expansion and contraction of the casing 3020 may also cause connection problems in this application.
With either the attachment of the end housing 3120 and plate 3110 assemblies to both ends of the casing 3020 or the attachment of the end housing 3120 and plate 3110 assembly to one end of the casing 3020 and the end plate 3111 to the other end, the structure of the printhead assembly according to the present invention is completed.
The thus-assembled printhead assembly can then be mounted to a printing unit to which the assembled length of the printhead assembly is applicable. Exemplary printing units to which the printhead module and printhead assembly of the present invention is applicable are as follows.
For a home office printing unit printing on A4 and letter-sized paper, a printhead assembly having a single printhead module comprising 11 printhead integrated circuits can be used to present a printhead width of 224 mm. This printing unit is capable of printing at approximately 60 pages per minute (ppm) when the nozzle speed is about 20 kHz. At this speed a maximum of about 1690×106 drops or about 1.6896 ml of ink is delivered per second for the entire printhead. This results in a linear printing speed of about 0.32 ms−1 or an area printing speed of about 0.07 sqms−1. A single PEC integrated circuit can be used to drive all 11 printhead integrated circuits, with the PEC integrated circuit calculating about 1.8 billion dots per second.
For a printing unit printing on A3 and tabloid-sized paper, a printhead assembly having a single printhead module comprising 16 printhead integrated circuits can be used to present a printhead width of 325 mm. This printing unit is capable of printing at approximately 120 ppm when the nozzle speed is about 55 kHz. At this speed a maximum of about 6758×106 drops or about 6.7584 ml of ink is delivered per second for the entire printhead. This results in a linear printing speed of about 0.87 ms−1 or an area printing speed of about 0.28 sqms−1. Four PEC integrated circuits can be used to each drive four of the printhead integrated circuits, with the PEC integrated circuits collectively calculating about 7.2 billion dots per second.
For a printing unit printing on a roll of wallpaper, a printhead assembly having one or more printhead modules providing 36 printhead integrated circuits can be used to present a printhead width of 732 mm. When the nozzle speed is about 55 kHz, a maximum of about 15206×106 drops or about 15.2064 ml of ink is delivered per second for the entire printhead. This results in a linear printing speed of about 0.87 ms−1 or an area printing speed of about 0.64 sqms−1. Nine PEC integrated circuits can be used to each drive four of the printhead integrated circuits, with the PEC integrated circuits collectively calculating about 16.2 billion dots per second.
For a wide format printing unit printing on a roll of print media, a printhead assembly having one or more printhead modules providing 92 printhead integrated circuits can be used to present a printhead width of 1869 mm. When the nozzle speed is in a range of about 15 to 55 kHz, a maximum of about 10598×106 to 38861×106 drops or about 10.5984 to 38.8608 ml of ink is delivered per second for the entire printhead. This results in a linear printing speed of about 0.24 to 0.87 ms−1 or an area printing speed of about 0.45 to 1.63 sqms−1. At the lower speeds, six PEC integrated circuits can be used to each drive 16 of the printhead integrated circuits (with one of the PEC integrated circuits driving 12 printhead integrated circuits), with the PEC integrated circuits collectively calculating about 10.8 billion dots per second. At the higher speeds, 23 PEC integrated circuits can be used each to drive four of the printhead integrated circuits, with the PEC integrated circuits collectively calculating about 41.4 billions dots per second.
For a “super wide” printing unit printing on a roll of print media, a printhead assembly having one or more printhead modules providing 200 printhead integrated circuits can be used to present a printhead width of 4064 mm. When the nozzle speed is about 15 kHz, a maximum of about 23040×106 drops or about 23.04 ml of ink is delivered per second for the entire printhead. This results in a linear printing speed of about 0.24 ms−1 or an area printing speed of about 0.97 sqms−1. Thirteen PEC integrated circuits can be used to each drive 16 of the printhead integrated circuits (with one of the PEC integrated circuits driving eight printhead integrated circuits), with the PEC integrated circuits collectively calculating about 23.4 billion dots per second.
For the above exemplary printing unit applications, the required printhead assembly may be provided by the corresponding standard length printhead module or built-up of several standard length printhead modules. Of course, any of the above exemplary printing unit applications may involve duplex printing with simultaneous double-sided printing, such that two printhead assemblies are used each having the number of printhead tiles given above. Further, those skilled in the art understand that these applications are merely examples and the number of printhead integrated circuits, nozzle speeds and associated printing capabilities of the printhead assembly depends upon the specific printing unit application.
Print Engine Controller Integrated Circuit
The functions and structure of the PEC integrated circuit applicable to the printhead assembly of the present invention will now be discussed with reference to FIGS. 60 to 62.
In the above-described exemplary embodiments of the present invention, the printhead integrated circuits 3051 of the printhead assembly 3010 are controlled by the PEC integrated circuits 3100 of the drive electronics. One or more PEC integrated circuits 3100 is or are provided in order to enable pagewidth printing over a variety of different sized pages. As described earlier, each of the PCBs 3090 supported by the PCB supports 3091 has one PEC integrated circuit 3100 which interfaces with four of the printhead integrated circuits 3051, where the PEC integrated circuit 3100 essentially drives the printhead integrated circuits 3051 and transfers received print data thereto in a form suitable for printing.
An exemplary PEC integrated circuit which is suited to driving the printhead integrated circuits of the present invention is described in the Applicant's co-pending U.S. patent applications Ser. No. 09/575,108 Ser. No. 09/575,109 , Ser. No. 09/575,110 , Ser. No. 09/607,985, Ser. No. 09/607,990 and Ser. No. 09/606,999 , which are incorporated herein by reference.
Referring to FIG. 60, the data flow and functions performed by the PEC integrated circuit 3100 will be described for a situation where the PEC integrated circuit 3100 is suited to driving a printhead assembly having a plurality of printhead modules 3030. As described above, the printhead module 3030 of one embodiment of the present invention utilises six channels of fluid for printing. These are:

    
    
        Cyan, Magenta and Yellow (CMY) for regular colour printing;
        Black (K) for black text and other black or greyscale printing;
        Infrared (IR) for tag-enabled applications; and
        Fixative (F) to enable printing at high speed.
    
    


As shown in FIG. 60, documents are typically supplied to the PEC integrated circuit 3100 by a computer system or the like, having Raster Image Processor(s) (RIP(s)), which is programmed to perform various processing steps 3131 to 3134 involved in printing a document prior to transmission to the PEC integrated circuit 3100. These steps typically involve receiving the document data (step 3131) and storing this data in a memory buffer of the computer system (step 3132), in which page layouts may be produced and any required objects may be added. Pages from the memory buffer are rasterized by the RIP (step 3133) and are then compressed (step 3134) prior to transmission to the PEC integrated circuit 3100. Upon receiving the page data, the PEC integrated circuit 3100 processes the data so as to drive the printhead integrated circuits 3051.
Due to the page-width nature of the printhead assembly of the present invention, each page must be printed at a constant speed to avoid creating visible artifacts. This means that the printing speed cannot be varied to match the input data rate. Document rasterization and document printing are therefore decoupled to ensure the printhead assembly has a constant supply of data. In this arrangement, a page is not printed until it is fully rasterized, and in order to achieve a high constant printing speed a compressed version of each rasterized page image is stored in memory. This decoupling also allows the RIP(s) to run ahead of the printer when rasterizing simple pages, buying time to rasterize more complex pages.
Because contone colour images are reproduced by stochastic dithering, but black text and line graphics are reproduced directly using dots, the compressed page image format contains a separate foreground bi-level black layer and background contone colour layer. The black layer is composited over the contone layer after the contone layer is dithered (although the contone layer has an optional black component). If required, a final layer of tags (in IR or black ink) is optionally added to the page for printout.
Dither matrix selection regions in the page description are rasterized to a contone-resolution bi-level bitmap which is losslessly compressed to negligible size and which forms part of the compressed page image. The IR layer of the printed page optionally contains encoded tags at a programmable density.
As described above, the RIP software/hardware rasterizes each page description and compresses the rasterized page image. Each compressed page image is transferred to the PEC integrated circuit 3100 where it is then stored in a memory buffer 3135. The compressed page image is then retrieved and fed to a page image expander 3136 in which page images are retrieved. If required, any dither may be applied to any contone layer by a dithering means 3137 and any black bi-level layer may be composited over the contone layer by a compositor 3138 together with any infrared tags which may be rendered by the rendering means 3139. Returning to a description of process steps, the PEC integrated circuit 3100 then drives the printhead integrated circuits 3051 to print the composited page data at step 140 to produce a printed page 141.
In this regard, the process performed by the PEC integrated circuit 3100 can be considered to consist of a number of distinct stages. The first stage has the ability to expand a JPEG-compressed contone CMYK layer, a Group 4 Fax-compressed bi-level dither matrix selection map, and a Group 4 Fax-compressed bi-level black layer, all in parallel. In parallel with this, bi-level IR tag data can be encoded from the compressed page image. The second stage dithers the contone CMYK layer using a dither matrix selected by a dither matrix select map, composites the bi-level black layer over the resulting bi-level K layer and adds the IR layer to the page. A fixative layer is also generated at each dot position wherever there is a need in any of the C, M, Y, K, or IR channels. The last stage prints the bi-level CMYK+IR data through the printhead assembly.
FIG. 61 shows an exemplary embodiment of the printhead assembly of the present invention including the PEC integrated circuit(s) 3100 in the context of the overall printing system architecture. As shown, the various components of the printhead assembly includes:

    
    
        a PEC integrated circuit 3100 which is responsible for receiving the compressed page images for storage in a memory buffer 3142, performing the page expansion, black layer compositing and sending the dot data to the printhead integrated circuits 3051. The PEC integrated circuit 3100 may also communicate with a master Quality Assurance (QA) integrated circuit 3143 and a (replaceable) ink cartridge QA integrated circuit 3144, and provides a means of retrieving the printhead assembly characteristics to ensure optimum printing;
        the memory buffer 3142 for storing the compressed page image and for scratch use during the printing of a given page. The construction and working of memory buffers is known to those skilled in the art and a range of standard integrated circuits and techniques for their use might be utilized in use of the PEC integrated circuit(s) 3100; and
        the master integrated circuit 3143 which is matched to the replaceable ink cartridge QA integrated circuit 3144. The construction and working of QA integrated circuits is known to those skilled in the art and a range of known QA processes might be utilized in use of the PEC integrated circuit(s) 3100;
    
    


As mentioned in part above, the PEC integrated circuit 3100 of the present invention essentially performs four basic levels of functionality:

    
    
        receiving compressed pages via a serial interface such as an IEEE 1394;
        acting as a print engine for producing a page from a compressed form. The print engine functionality includes expanding the page image, dithering the contone layer, compositing the black layer over the contone layer, optionally adding infrared tags, and sending the resultant image to the printhead integrated circuits;
        acting as a print controller for controlling the printhead integrated circuits and stepper motors of the printing system; and
        serving as two standard low-speed serial ports for communication with the two QA integrated circuits. In this regard, two ports are used, and not a single port, so as to ensure strong security during authentication procedures.
    
    


These functions are now described in more detail with reference to FIG. 62 which provides a more specific illustration of the PEC integrated circuit architecture according to an exemplary embodiment of the present invention.
The PEC integrated circuit 3100 incorporates a simple micro-controller CPU core 3145 to perform the following functions:

    
    
        perform QA integrated circuit authentication protocols via a serial interface 3146 between print pages;
        run the stepper motor of the printing system via a parallel interface 3147 during printing to control delivery of the paper to the printhead integrated circuits 3051 for printing (the stepper motor requires a 5 KHz process);
        synchronize the various components of the PEC integrated circuit 3100 during printing;
        provide a means of interfacing with external data requests (programming registers etc.);
        provide a means of interfacing with the corresponding printhead module's low-speed data requests (such as reading the characterization vectors and writing pulse profiles); and
        provide a means of writing the portrait and landscape tag structures to an external DRAM 3148.
    
    


In order to perform the page expansion and printing process, the PEC integrated circuit 3100 includes a high-speed serial interface 3149 (such as a standard IEEE 1394 interface), a standard JPEG decoder 3150, a standard Group 4 Fax decoder 3151, a custom halftoner/compositor (HC) 3152, a custom tag encoder 3153, a line loader/formatter (LLF) 154, and a printhead interface 3155 (PHI) which communicates with the printhead integrated circuits 3051. The decoders 3150 and 3151 and the tag encoder 3153 are buffered to the HC 3152. The tag encoder 3153 establishes an infrared tag(s) to a page according to protocols dependent on what uses might be made of the page.
The print engine function works in a double-buffered manner. That is, one page is loaded into the external DRAM 3148 via a DRAM interface 3156 and a data bus 3157 from the high-speed serial interface 3149, while the previously loaded page is read from the DRAM 3148 and passed through the print engine process. Once the page has finished printing, then the page just loaded becomes the page being printed, and a new page is loaded via the high-speed serial interface 3149.
At the aforementioned first stage, the process expands any JPEG-compressed contone (CMYK) layers, and expands any of two Group 4 Fax-compressed bi-level data streams. The two streams are the black layer (although the PEC integrated circuit 3100 is actually colour agnostic and this bi-level layer can be directed to any of the output inks) and a matte for selecting between dither matrices for contone dithering. At the second stage, in parallel with the first, any tags are encoded for later rendering in either IR or black ink.
Finally, in the third stage the contone layer is dithered, and position tags and the bi-level spot layer are composited over the resulting bi-level dithered layer. The data stream is ideally adjusted to create smooth transitions across overlapping segments in the printhead assembly and ideally it is adjusted to compensate for dead nozzles in the printhead assembly. Up to six channels of bi-level data are produced from this stage.
However, it will be understood by those skilled in the art that not all of the six channels need be present on the printhead module 3030. For example, the printhead module 3030 may provide for CMY only, with K pushed into the CMY channels and IR ignored. Alternatively, the position tags may be printed in K if IR ink is not available (or for testing purposes). The resultant bi-level CMYK-IR dot-data is buffered and formatted for printing with the printhead integrated circuits 3051 via a set of line buffers (not shown). The majority of these line buffers might be ideally stored on the external DRAM 3148. In the final stage, the six channels of bi-level dot data are printed via the PHI 3155.
The HC 3152 combines the functions of halftoning the contone (typically CMYK) layer to a bi-level version of the same, and compositing the spot1 bi-level layer over the appropriate halftoned contone layer(s). If there is no K ink, the HC 3152 is able to map K to CMY dots as appropriate. It also selects between two dither matrices on a pixel-by-pixel basis, based on the corresponding value in the dither matrix select map. The input to the HC 3152 is an expanded contone layer (from the JPEG decoder 146) through a buffer 3158, an expanded bi-level spot1 layer through a buffer 3159, an expanded dither-matrix-select bitmap at typically the same resolution as the contone layer through a buffer 3160, and tag data at full dot resolution through a buffer (FIFO) 3161.
The HC 3152 uses up to two dither matrices, read from the external DRAM 3148. The output from the HC 3152 to the LLF 3154 is a set of printer resolution bi-level image lines in up to six colour planes. Typically, the contone layer is CMYK or CMY, and the bi-level spot1 layer is K. Once started, the HC 3152 proceeds until it detects an “end-of-page” condition, or until it is explicitly stopped via its control register (not shown).
The LLF 3154 receives dot information from the HC 3152, loads the dots for a given print line into appropriate buffer storage (some on integrated circuit (not shown) and some in the external DRAM 3148) and formats them into the order required for the printhead integrated circuits 3051. Specifically, the input to the LLF 3154 is a set of six 32-bit words and a DataValid bit, all generated by the HC 3152. The output of the LLF 3154 is a set of 190 bits representing a maximum of 15 printhead integrated circuits of six colours. Not all the output bits may be valid, depending on how many colours are actually used in the printhead assembly.
The physical placement of the nozzles on the printhead assembly of an exemplary embodiment of the present invention is in two offset rows, which means that odd and even dots of the same colour are for two different lines. The even dots are for line L, and the odd dots are for line L-2. In addition, there is a number of lines between the dots of one colour and the dots of another. Since the six colour planes for the same dot position are calculated at one time by the HC 3152, there is a need to delay the dot data for each of the colour planes until the same dot is positioned under the appropriate colour nozzle. The size of each buffer line depends on the width of the printhead assembly. Since a single PEC integrated circuit 3100 can generate dots for up to 15 printhead integrated circuits 3051, a single odd or even buffer line is therefore 15 sets of 640 dots, for a total of 9600 bits (1200 bytes). For example, the buffers required for six colour odd dots totals almost 45 KBytes.
The PHI 3155 is the means by which the PEC integrated circuit 3100 loads the printhead integrated circuits 3051 with the dots to be printed, and controls the actual dot printing process. It takes input from the LLF 3154 and outputs data to the printhead integrated circuits 3051. The PHI 3155 is capable of dealing with a variety of printhead assembly lengths and formats. The internal structure of the PHI 3155 allows for a maximum of six colours, eight printhead integrated circuits 3051 per transfer, and a maximum of two printhead integrated circuit 3051 groups which is sufficient for a printhead assembly having 15 printhead integrated circuits 3051 (8.5 inch) printing system capable of printing on A4/Letter paper at full speed.
A combined characterization vector of the printhead assembly 3010 can be read back via the serial interface 3146. The characterization vector may include dead nozzle information as well as relative printhead module alignment data. Each printhead module can be queried via its low-speed serial bus 3162 to return a characterization vector of the printhead module. The characterization vectors from multiple printhead modules can be combined to construct a nozzle defect list for the entire printhead assembly and allows the PEC integrated circuit 3100 to compensate for defective nozzles during printing. As long as the number of defective nozzles is low, the compensation can produce results indistinguishable from those of a printhead assembly with no defective nozzles:
Fluid Distribution Stack
An exemplary structure of the fluid distribution stack of the printhead tile will now be described with reference to FIG. 63.
FIG. 63 shows an exploded view of the fluid distribution stack 3500 with the printhead integrated circuit 3051 also shown in relation to the stack 3500. In the exemplary embodiment shown in FIG. 63, the stack 3500 includes three layers, an upper layer 3510, a middle layer 3520 and a lower layer 3530, and further includes a channel layer 3540 and a plate 3550 which are provided in that order on top of the upper layer 3510. Each of the layers 3510, 3520 and 3530 are formed as stainless-steel or micro-moulded plastic material sheets.
The printhead integrated circuit 3051 is bonded onto the upper layer 3510 of the stack 3500, so as to overlie an array of holes 3511 etched therein, and therefore to sit adjacent the stack of the channel layer 3540 and the plate 3550. The printhead integrated circuit 3051 itself is formed as a multi-layer stack of silicon which has fluid channels (not shown) in a bottom layer 3051a. These channels are aligned with the holes 3511 when the printhead integrated circuit 3051 is mounted on the stack 3500. In one embodiment of the present invention, the printhead integrated circuits 3051 are approximately 1 mm in width and 21 mm in length. This length is determined by the width of the field of a stepper which is used to fabricate the printhead integrated circuit 3051. Accordingly, the holes 3511 are arranged to conform to these dimensions of the printhead integrated circuit 3051.
The upper layer 3510 has channels 3512 etched on the underside thereof (FIG. 63 shows only some of the channels 3512 as hidden detail). The channels 3512 extend as shown so that their ends align with holes 3521 of the middle layer 3520. Different ones of the channels 3512 align with different ones of the holes 3521. The holes 3521, in turn, align with channels 3531 in the lower layer 3530.
Each of the channels 3531 carries a different respective colour or type of ink, or fluid, except for the last channel, designated with the reference numeral 3532. The last channel 3532 is an air channel and is aligned with further holes 3522 of the middle layer 3520, which in turn are aligned with further holes 3513 of the upper layer 3510. The further holes 3513 are aligned with inner sides 3541 of slots 3542 formed in the channel layer 3540, so that these inner sides 3541 are aligned with, and therefore in fluid-flow communication with, the air channel 3532, as indicated by the dashed line 30543.
The lower layer 3530 includes the inlet ports 3054 of the printhead tile 3050, with each opening into the corresponding ones of the channels 3531 and 3532.
In order to feed air to the printhead integrated circuit surface, compressed filtered air from an air source (not shown) enters the air channel 3532 through the corresponding inlet port 3054 and passes through the holes 3522 and 3513 and then the slots 3542 in the middle layer 3520, the upper layer 3510 and the channel layer 3540, respectively. The air enters into a side surface 3051b of the printhead integrated circuit 3051 in the direction of arrows A and is then expelled from the printhead integrated circuit 3051 substantially in the direction of arrows B. A nozzle guard 3051c may be further arranged on a top surface of the printhead integrated circuit 3051 partially covering the nozzles to assist in keeping the nozzles clear of print media dust.
In order to feed different colour and types of inks and other fluids (not shown) to the nozzles, the different inks and fluids enter through the inlet ports 3054 into the corresponding ones of the channels 3531, pass through the corresponding holes 3521 of the middle layer 3520, flow along the corresponding channels 3512 in the underside of the upper layer 3510, pass through the corresponding holes 3511 of the upper layer 3510, and then finally pass through the slots 3542 of the channel layer 3540 to the printhead integrated circuit 3051, as described earlier.
In traversing this path, the flow diameters of the inks and fluids are gradually reduced from the macro-sized flow diameter at the inlet ports 3054 to the required micro-sized flow diameter at the nozzles of the printhead integrated circuit 3051.
The exemplary embodiment of the fluid distribution stack shown in FIG. 63 is arranged to distribute seven different fluids to the printhead integrated circuit, including air, which is in conformity with the earlier described exemplary embodiment of the ducts of the fluid channel member. However, it will be understood by those skilled in the art that a greater or lesser number of fluids may be used depending on the specific printing application, and therefore the fluid distribution stack can be configured as necessary.
Nozzles and Actuators
An exemplary nozzle arrangement which is suitable for the printhead assembly of the present invention is described in the Applicant's co-pending/granted applications identified below which are incorporated herein by reference.

















6,227,652
6,213,588
6,213,589
6,231,163
6,247,795
6,394,581


6,244,691
6,257,704
6,416,168
6,220,694
6,257,705
6,247,794


6,234,610
6,247,793
6,264,306
6,241,342
6,247,792
6,264,307


6,254,220
6,234,611
6,302,528
6,283,582
6,239,821
6,338,547


6,247,796
6,557,977
6,390,603
6,362,843
6,293,653
6,312,107


6,227,653
6,234,609
6,238,040
6,188,415
6,227,654
6,209,989


6,247,791
6,336,710
6,217,153
6,416,167
6,243,113
6,283,581


6,247,790
6,260,953
6,267,469
6,273,544
6,309,048
6,420,196


6,443,558
6,439,689
6,378,989
09/425,420
6,634,735
6,299,289


6,299,290
6,425,654
6,623,101
6,406,129
6,505,916
6,457,809


6,550,895
6,457,812
6,428,133
6,390,605
6,322,195
6,612,110


6,480,089
6,460,778
6,305,788
6,426,014
6,364,453
6,457,795


6,595,624
6,417,757
6,623,106
10/129,433
6,575,549
6,659,590


10.129,503
10/129,437
6,439,693
6,425,971
6,478,406
6,315,399


6,338,548
6,540,319
6,328,431
6,328,425
09/575,127
6,383,833


6,464,332
6,390,591
09/575,152
09/575,176
6,322,194
09/575,177


6,629,745
09/608,780
6,428,139
6,575,549
09/693,079
09/693,135


6,428,142
6,565,193
6,609,786
6,609,787
6,439,908
09/693,735


6,588,885
6,502,306
6,652,071
10/407,212
10/407,207
JUM003


JUM004
10/302,274
10/302,669
10/303,352
10/303,348
10/303,433


10/303,312
10/302,668
10/302,577
10/302,644
10/302,618
10/302,617


10/302,297
MTB01
MTB02
MTB03
MTB04
MTB05


MTB06
MTB07
MTB08
MTB09
MTB10
MTB11


MTB12
MTB13
MTB14









This nozzle arrangement will now be described with reference to FIGS. 64 to 73. One nozzle arrangement which is incorporated in each of the printhead integrated circuits 3051 mounted on the printhead tiles 3050 (see FIG. 25A) includes a nozzle and corresponding actuator. FIG. 64 shows an array of the nozzle arrangements 3801 formed on a silicon substrate 3815. The nozzle arrangements are identical, but in one embodiment, different nozzle arrangements are fed with different coloured inks and fixative. It will be noted that rows of the nozzle arrangements 3801 are staggered with respect to each other, allowing closer spacing of ink dots during printing than would be possible with a single row of nozzles. The multiple rows also allow for redundancy (if desired), thereby allowing for a predetermined failure rate per nozzle.
Each nozzle arrangement 3801 is the product of an integrated circuit fabrication technique. As illustrated, the nozzle arrangement 3801 is constituted by a micro-electromechanical system (MEMS).
For clarity and ease of description, the construction and operation of a single nozzle arrangement 3801 will be described with reference to FIGS. 65 to 73.
Each printhead integrated circuit 3051 includes a silicon wafer substrate 3815. 0.42 Micron 1 P4M 12 volt CMOS microprocessing circuitry is positioned on the silicon wafer substrate 3815.
A silicon dioxide (or alternatively glass) layer 3817 is positioned on the wafer substrate 3815. The silicon dioxide layer 3817 defines CMOS dielectric layers. CMOS top-level metal defines a pair of aligned aluminium electrode contact layers 3830 positioned on the silicon dioxide layer 3817. Both the silicon wafer substrate 3815 and the silicon dioxide layer 3817 are etched to define an ink inlet channel 3814 having a generally circular cross section (in plan). An aluminium diffusion barrier 3828 of CMOS metal 1, CMOS metal 2/3 and CMOS top level metal is positioned in the silicon dioxide layer 3817 about the ink inlet channel 3814. The diffusion barrier 3828 serves to inhibit the diffusion of hydroxyl ions through CMOS oxide layers of the drive circuitry layer 3817.
A passivation layer in the form of a layer of silicon nitride 3831 is positioned over the aluminium contact layers 3830 and the silicon dioxide layer 3817. Each portion of the passivation layer 3831 positioned over the contact layers 3830 has an opening 3832 defined therein to provide access to the contacts 3830.
The nozzle arrangement 3801 includes a nozzle chamber 3829 defined by an annular nozzle wall 3833, which terminates at an upper end in a nozzle roof 3834 and a radially inner nozzle rim 3804 that is circular in plan. The ink inlet channel 3814 is in fluid communication with the nozzle chamber 3829. At a lower end of the nozzle wall, there is disposed a movable rim 3810, that includes a movable seal lip 3840. An encircling wall 3838 surrounds the movable nozzle, and includes a stationary seal lip 3839 that, when the nozzle is at rest as shown in FIG. 65, is adjacent the moving rim 3810. A fluidic seal 3811 is formed due to the surface tension of ink trapped between the stationary seal lip 3839 and the moving seal lip 3840. This prevents leakage of ink from the chamber whilst providing a low resistance coupling between the encircling wall 3838 and the nozzle wall 3833.
As best shown in FIG. 72, a plurality of radially extending recesses 3835 is defined in the roof 3834 about the nozzle rim 3804. The recesses 3835 serve to contain radial ink flow as a result of ink escaping past the nozzle rim 3804.
The nozzle wall 3833 forms part of a lever arrangement that is mounted to a carrier 3836 having a generally U-shaped profile with a base 3837 attached to the layer 3831 of silicon nitride.
The lever arrangement also includes a lever arm 3818 that extends from the nozzle walls and incorporates a lateral stiffening beam 3822. The lever arm 3818 is attached to a pair of passive beams 3806, formed from titanium nitride (TiN) and positioned on either side of the nozzle arrangement, as best shown in FIGS. 68 and 71. The other ends of the passive beams 3806 are attached to the carrier 3836.
The lever arm 3818 is also attached to an actuator beam 3807, which is formed from TiN. It will be noted that this attachment to the actuator beam is made at a point a small but critical distance higher than the attachments to the passive beam 3806.
As best shown in FIGS. 68 and 71, the actuator beam 3807 is substantially U-shaped in plan, defining a current path between the electrode 3809 and an opposite electrode 3841. Each of the electrodes 3809 and 3841 is electrically connected to a respective point in the contact layer 3830. As well as being electrically coupled via the contacts 3809, the actuator beam is also mechanically anchored to anchor 3808. The anchor 3808 is configured to constrain motion of the actuator beam 3807 to the left of FIGS. 65 to 67 when the nozzle arrangement is in operation.
The TiN in the actuator beam 3807 is conductive, but has a high enough electrical resistance that it undergoes self-heating when a current is passed between the electrodes 3809 and 3841. No current flows through the passive beams 3806, so they do not expand.
In use, the device at rest is filled with ink 3813 that defines a meniscus 3803 under the influence of surface tension. The ink is retained in the chamber 3829 by the meniscus, and will not generally leak out in the absence of some other physical influence.
As shown in FIG. 66, to fire ink from the nozzle, a current is passed between the contacts 3809 and 3841, passing through the actuator beam 3807. The self-heating of the beam 3807 due to its resistance causes the beam to expand. The dimensions and design of the actuator beam 3807 mean that the majority of the expansion in a horizontal direction with respect to FIGS. 65 to 67. The expansion is constrained to the left by the anchor 3808, so the end of the actuator beam 3807 adjacent the lever arm 3818 is impelled to the right.
The relative horizontal inflexibility of the passive beams 3806 prevents them from allowing much horizontal movement the lever arm 3818. However, the relative displacement of the attachment points of the passive beams and actuator beam respectively to the lever arm causes a twisting movement that causes the lever arm 3818 to move generally downwards. The movement is effectively a pivoting or hinging motion. However, the absence of a true pivot point means that the rotation is about a pivot region defined by bending of the passive beams 3806.
The downward movement (and slight rotation) of the lever arm 3818 is amplified by the distance of the nozzle wall 3833 from the passive beams 3806. The downward movement of the nozzle walls and roof causes a pressure increase within the chamber 3029, causing the meniscus to bulge as shown in FIG. 66. It will be noted that the surface tension of the ink means the fluid seal 3011 is stretched by this motion without allowing ink to leak out.
As shown in FIG. 67, at the appropriate time, the drive current is stopped and the actuator beam 3807 quickly cools and contracts. The contraction causes the lever arm to commence its return to the quiescent position, which in turn causes a reduction in pressure in the chamber 3829. The interplay of the momentum of the bulging ink and its inherent surface tension, and the negative pressure caused by the upward movement of the nozzle chamber 3829 causes thinning, and ultimately snapping, of the bulging meniscus to define an ink drop 3802 that continues upwards until it contacts the adjacent print media.
Immediately after the drop 3802 detaches, the meniscus forms the concave shape shown in FIG. 65. Surface tension causes the pressure in the chamber 3829 to remain relatively low until ink has been sucked upwards through the inlet 3814, which returns the nozzle arrangement and the ink to the quiescent situation shown in FIG. 65.
As best shown in FIG. 68, the nozzle arrangement also incorporates a test mechanism that can be used both post-manufacture and periodically after the printhead assembly is installed. The test mechanism includes a pair of contacts 3820 that are connected to test circuitry (not shown). A bridging contact 3819 is provided on a finger 3843 that extends from the lever arm 3818. Because the bridging contact 3819 is on the opposite side of the passive beams 3806, actuation of the nozzle causes the priding contact to move upwardly, into contact with the contacts 3820. Test circuitry can be used to confirm that actuation causes this closing of the circuit formed by the contacts 3819 and 820. If the circuit is closed appropriately, it can generally be assumed that the nozzle is operative.
Exemplary Method of Assembling Components
An exemplary method of assembling the various above-described modular components, of the printhead assembly in accordance with one embodiment of the present invention will now be described. It is to be understood that the below described method represents only one example of assembling a particular printhead assembly of the present invention, and different methods may be employed to assemble this exemplary printhead assembly or other exemplary printhead assemblies of the present invention.
The printhead integrated circuits 3051 and the printhead tiles 3050 are assembled as follows:

    
    
        A. The printhead integrated circuit 3051 is first prepared by forming nozzles in an upper surface thereof, which are spaced so as to be capable of printing with a resolution of 1600 dpi;
        B. The fluid distribution stacks 3500 (from which the printhead tiles 3050 are formed) are constructed so as to have the three layers 3510, 3520 and 3530, the channel layer 3540 and the plate 3550 made of stainless steel bonded together in a vacuum furnace into a single body via metal inter-diffusion, where the inner surface of the lower layer 3530 and the surfaces of the middle and upper layers 3520 and 3510 are etched so as to be provided with the channels and holes 3531 and 3532, 3521 and 3522, and 3511 to 3513, respectively, so as to be capable of transporting the CYMK and IR inks and fixative to the individual nozzles of the printhead integrated circuit 3051 and air to the surface of the printhead integrated circuit 3051, as described earlier. Further, the outer surface of the lower layer 3530 is etched so as to be provided with the inlet ports 3054;
        C. An adhesive, such as a silicone adhesive, is then applied to an upper surface of the fluid distribution stack 3500 for attaching the printhead integrated circuit 3051 and the (fine pitch) PCB 3052 in close proximity thereto;
        D. The printhead integrated circuit 3051 and the PCB 3052 are picked up, pre-centred and then bonded on the upper surface of the fluid distribution stack 3500 via a pick-and-place robot;
        E. This assembly is then placed in an oven whereby the adhesive is allowed to cure so as to fix the printhead integrated circuit 3051 and the PCB 3052 in place;
        F. Connection between the printhead integrated circuit 3051 and the PCB 3052 is then made via a wire bonding machine, whereby a 25 micron diameter alloy, gold or aluminium wire is bonded between the bond pads on the printhead integrated circuit 3051 and conductive pads on the PCB 3052;
        G. The wire bond area is then encapsulated in an epoxy adhesive dispensed by an automatic two-head dispenser. A high viscosity non-sump adhesive is firstly applied to draw a dam around the wire bond area, and the dam is then filled with a low viscosity adhesive to fully encapsulate the wire bond area beneath the adhesive;
        H. This assembly is then placed on levelling plates in an oven and heat cured to form the epoxy encapsulant 3053. The levelling plates ensure that no encapsulant flows from the assembly during curing; and
        I. The thus-formed printhead tiles 3050 and printhead integrated circuits 3051 are ‘wet’ tested with a suitable fluid, such as pure water, to ensure reliable performance and are then dried out, where they are then ready for assembly on the fluid channel member 3040.
    
    


The units composed of the printhead tiles 3050 and the printhead integrated circuits 3051 are prepared for assembly to the fluid channel members 3040 as follows:

    
    
        J. The (extended) flex PCB 3080 is prepared to provide data and power connection to the printhead integrated circuit 3051 from the PCB 3090 and busbars 3071, 3072 and 3073; and
        K. The flex PCB 3080 is aligned with the PCB 3052 and attached using a hot bar soldering machine.
    
    


The fluid channel members 3040 and the casing 3020 are formed and assembled as follows:

    
    
        L. Individual fluid channel members 3040 are formed by injection moulding an elongate body portion 3044a so as to have seven individual grooves (channels) extending therethrough and the two longitudinally extending tabs 3043 extending therealong on either side thereof. The (elongate) lid portion 3044b is also moulded so as to be capable of enclosing the body portion 3044a to separate each of the channels. The body and lid portions are both moulded so as to have end portions which form the female and male end portions 3045 and 3046 when assembled together. The lid portion 3044b and the body portion 3044a are then adhered together with epoxy and cured so as to form the seven ducts 3041;
        M. The casing 3020 is then formed by extruding aluminium to a desired configuration and length by separately forming the (elongate) support frame 3022, with the channel 3021 formed on the upper wall 3027 thereof, and the (elongate) cover portion 3023;
        N. The end plate 3110 is attached with screws via the threaded portions 3022a and 3022b formed in the support frame 3022 to one (first) end of the casing 3020, and the end plate 3111 is attached with screws via the threaded portions 3022a and 3022b to the other (second) end of the casing 3020;
        O. An epoxy is applied to the appropriate regions (i.e., so as not to cover the channels) of either a female or male connector 3047 or 3048, and either the female or male connecting section 3049a or 3049b of a capping member 3049 via a controlled dispenser;
        P. An epoxy is applied to the appropriate regions (i.e., so as not to cover the channels) of the female and male end portions 3045 and 3046 of the plurality of fluid channel members 3040 to be assembled together, end-to-end, so as to correspond to the desired length via the controlled dispenser;
        Q. The female or male connector 3047 or 3048 is then attached to the male or female end portion 3046 or 3045 of the fluid channel member 3040 which is to be at the first end of the plurality of fluid channel members 3040 and the female or male connecting section 3049a or 3049b of the capping member 3049 is attached to the male or female end portion 3046 or 3045 of the fluid channel member 3040 which is to be at the second end of the plurality of fluid channel members 3040;
        R. Each of the fluid channel members 3040 is then placed within the channel 3021 one-by-one.
    
    


Firstly, the (first) fluid channel member 3040 to be at the first end is placed within the channel 3021 at the first end, and is secured in place by way of the PCB supports 3091 which are clipped into the support frame 3022, in the manner described earlier, so that the unconnected end portion 3045 or 3046 of the fluid channel member 3040 is left exposed with the epoxy thereon. Then, a second member 3040 is placed in the channel 3021 so as to mate with the first fluid channel member 3040 via its corresponding end portion 3045 or 3046 and the epoxy therebetween and is then clipped into place with its PCB supports 3091. This can then be repeated until the final fluid channel member 3040 is in place at the second end of the channel 3021. Of course, only one fluid channel member 3040 may be used, in which case it may have a connector 3047 or 3048 attached to one end portion 3046 or 3045 and a capping member 3049 attached at the other end portion 3045 or 3046;

    
    
        S. This arrangement is then placed in a compression jig, whereby a compression force is applied against the ends of the assembly to assist in sealing the connections between the individual fluid channel members 3040 and their end connector 3047 or 3048 and capping member 3049. The complete assembly and jig is then placed in an oven at a temperature of about 100° C. for a predefined period, for example, about 45 minutes, to enhance the curing of the adhesive connections. However, other methods of curing, such as room temperature curing, could also be employed;
        T. Following curing, the arrangement is pressure tested to ensure the integrity of the seal between the individual fluid channel members 3040, the connector 3047 or 3048, and the capping member 3049; and
        U. The exposed upper surface of the assembly is then oxygen plasma cleaned to facilitate attachment of the individual printhead tiles 3050 thereto.
    
    


The printhead tiles 3050 are attached to the fluid channel members 3040 as follows:

    
    
        V. Prior to placement of the individual printhead tiles 3050 upon the upper surface of the fluid channel members 3040, the bottom surface of the printhead tiles 3050 are argon plasma cleaned to enhance bonding. An adhesive is then applied via a robotic dispenser to the upper surface of the fluid channel members 3040 in the form of an epoxy in strategic positions on the upper surface around and symmetrically about the outlet ports 3042. To assist in fixing the printhead tiles 3050 in place a fast acting adhesive, such as cyanoacrylate, is applied in the remaining free areas of the upper surface as the adhesive drops 3062 immediately prior to placing the printhead tiles 3050 thereon;
        W. Each of the individual printhead tiles 3050 is then carefully aligned and placed on the upper surface of the fluid channel members 3040 via a pick-and-place robot, such that a continuous print surface is defined along the length of the printhead module 3030 and also to ensure that that the outlet ports 3042 of the fluid channel members 3040 align with the inlet ports 3054 of the individual printhead tiles 3050. Following placement, the pick-and-place robot applies a pressure on the printhead tile 3050 for about 5 to 10 seconds to assist in the setting of the cyanoacrylate and to fix the printhead tile 3050 in place. This process is repeated for each printhead tile 3050;
        X. This assembly is then placed in an oven at about 100° C. for about 45 minutes to cure the epoxy so as to form the gasket member 3060 and the locators 3061 for each printhead tile 3050 which seal the fluid connection between each of the outlet and inlet ports 3042 and 3054. This fixes the printhead tiles 3050 in place on the fluid channel members 3040 so as to define the print surface; and
        Y. Following curing, the assembly is inspected and tested to ensure correct alignment and positioning of the printhead tiles 3050.
    
    


The printhead assembly 3010 is assembled as follows:

    
    
        Z. The support member 3112 is attached to the end PCB supports 3091 so as to align with the recessed portion 3091b of the end supports 3091;
        AA. The connecting members 3102 are placed in the abutting recessed portions 3091b between the adjacent PCB supports 3091 and in the abutting recessed portions 3112b and 3091b of the support members 3112 and end PCB supports 3091, respectively;
        BB. The PCBs 3090, each having assembled thereon a PEC integrated circuit 3100 and its associated circuitry, are then mounted on the PCB supports 3091 along the length of the casing 3020 and are retained in place between the notch portions 3096a of the retaining clips 3096 and the recessed portions 3093a and locating lugs 3093b of the base portions 3093 of the PCB supports 3091. As described earlier, the PCBs 3090 can be arranged such that the PEC integrated circuit 3100 of one PCB 3090 drives the printhead integrated circuits 3051 of four printhead tiles 3050, or of eight printhead tiles 3050, or of 16 printhead tiles 3050. Each of the PCBs 3090 include the connection strips 3090a and 3090b on the inner face thereof which communicate with the connecting members 3102 allowing data transfer between the PEC integrated circuits 3100 of each of the PCBs 3090, between the printhead integrated circuits 3051 and PEC integrated circuits 3100 of each of the PCBs 3090, and between the data connection portion 3117 of the connector arrangement 3115;
        CC. The connector arrangement 3115, with the power supply, data and fluid delivery connection portions 3116, 3117 and 3118 attached thereto, is attached to the end plate 3110 with screws so that the region 3115c of the connector arrangement 3115 is clipped into the clip portions 3112d of the support member 3112;
        DD. The busbars 3071, 3072 and 3073 are inserted into the corresponding channelled recesses 3095a, 3095b and 3095c of the plurality of PCB supports 3091 and are connected at their ends to the corresponding contact screws 3116a, 3116b and 3116c of the power supply connection portion 3116 of the connector arrangement 3115. The busbars 3071, 3072 and 3073 provide a path for power to be distributed throughout the printhead assembly;
        EE. Each of the flex PCBs 3080 extending from each of the printhead tiles 3050 is then connected to the connectors 3098 of the corresponding PCBs 3090 by slotting the slot regions 81 into the connectors 3098;
        FF. The pressure plates 3074 are then clipped onto the PCB supports 3091 by engaging the holes 3074a and the tab portions 3074c of the holes 3074b with the corresponding retaining clips 3099 and 3096 of the PCB supports 3091, such that the raised portions 75 of the pressure plates 3074 urge the power contacts of the flex PCBs 3080 into contact with each of the busbars 3071, 3072 and 3073, thereby providing a path for the transfer of power between the busbars 3071, 3072 and 3073, the PCBs 3090 and the printhead integrated circuits 3051;
        GG. The internal fluid delivery tubes 3006 are then attached to the corresponding tubular portions 3047b or 3048b of the female or male connector 3047 or 3048; and
        HH. The elongate, aluminium cover portion 3023 of the casing 3020 is then placed over the assembly and screwed into place via screws through the remaining holes in the end plates 3110 and 3111 into the threaded portions 3023b of the cover portion 3023, and the end housing 3120 is placed over the connector arrangement 3115 and screwed into place with screws into the end plate 3110 thereby completing the outer housing of the printhead assembly and so as to provide electrical and fluid communication between the printhead assembly and a printer unit. The external fluid tubes or hoses can then be assembled to supply ink and the other fluids to the channels ducts. The cover portion 3023 can also act as a heat sink for the PEC integrated circuits 3100 if the fin portions 3023d are provided thereon, thereby protecting the circuitry of the printhead assembly 3010.
    
    


Testing of the printhead assembly occurs as follows:

    
    
        II. The thus-assembled printhead assembly 3010 is moved to a testing area and inserted into a final print test machine which is essentially a working printing unit, whereby connections from the printhead assembly 3010 to the fluid and power supplies are manually performed;
        JJ. A test page is printed and analysed and appropriate adjustments are made to finalise the printhead electronics; and
        KK. When passed, the print surface of the printhead assembly 3010 is capped and a plastic sealing film is applied to protect the printhead assembly 3010 until product installation.

Nozzle Arrangement—Schematic Overview

    
    


The fabrication of a variety of nozzles is disclosed in detail throughout this specification and the documents incorporated by cross-reference. In particular, a detailed description of the thermal bend actuator nozzles shown in FIGS. 64 to 73 is provided later in this specification. However, FIGS. 74 to 89 provide a useful schematic overview of the structure and operation of this type of nozzle.
It should be noted that the reference numbering used to identify particular features in FIGS. 74 to 89 does not correspond to the reference numbering used in other Figures or sections of this specification.
The nozzle arrangement shown in FIGS. 74 to 89 has a nozzle chamber containing ink and a thermal actuator connected to a paddle positioned within the chamber. The thermal bend actuator device is actuated so as to eject ink from the nozzle chamber. The preferred embodiment includes a particular thermal actuator, which includes a series of tapered portions for providing conductive heating of a conductive trace. The actuator is connected to the paddle via an arm received through a slotted wall of the nozzle chamber. The actuator arm has a mating shape so as to mate substantially with the surfaces of the slot in the nozzle chamber wall.
Turning initially to FIG. 74-76, there is provided schematic illustrations of the basic operation of a nozzle arrangement of the invention. A nozzle chamber I is provided filled with ink 2 by means of an ink inlet channel 3 which can be etched through a wafer substrate on which the nozzle chamber 1 rests. The nozzle chamber 1 further includes an ink ejection port 4 around which an ink meniscus forms.
Inside the nozzle chamber 1 is a paddle type device 7 which is interconnected to an actuator 8 through a slot in the wall of the nozzle chamber 1. The actuator 8 includes a heater means eg. 9 located adjacent to an end portion of a post 10. The post 10 is fixed to a substrate.
When it is desired to eject a drop from the nozzle chamber 1, as illustrated in FIG. 75, the heater means 9 is heated so as to undergo thermal expansion. Preferably, the heater means 9 itself or the other portions of the actuator 8 are built from materials having a high bend efficiency where the bend efficiency is defined as




  
    bend
    ⁢
    
      
    
    ⁢
    efficiency
  
  =
  
    
      
        Young
        '
      
      ⁢
      s
      ⁢
      
        
      
      ⁢
      Modulus
      ×
      
        (
        
          Coefficient
          ⁢
          
            
          
          ⁢
          of
          ⁢
          
            
          
          ⁢
          thermal
          ⁢
          
            
          
          ⁢
          Expansion
        
        )
      
    
    
      Density
      ×
      Specific
      ⁢
      
        
      
      ⁢
      Heat
      ⁢
      
        
      
      ⁢
      Capacity
    
  




A suitable material for the heater elements is a copper nickel alloy which can be formed so as to bend a glass material.
The heater means 9 is ideally located adjacent the end portion of the post 10 such that the effects of activation are magnified at the paddle end 7 such that small thermal expansions near the post 10 result in large movements of the paddle end.
The heater means 9 and consequential paddle movement causes a general increase in pressure around the ink meniscus 5 which expands, as illustrated in FIG. 75, in a rapid manner. The heater current is pulsed and ink is ejected out of the port 4 in addition to flowing in from the ink channel 3.
Subsequently, the paddle 7 is deactivated to again return to its quiescent position. The deactivation causes a general reflow of the ink into the nozzle chamber. The forward momentum of the ink outside the nozzle rim and the corresponding backflow results in a general necking and breaking off of the drop 12 which proceeds to the print media. The collapsed meniscus 5 results in a general sucking of ink into the nozzle chamber 2 via the ink flow channel 3. In time, the nozzle chamber 1 is refilled such that the position in FIG. 74 is again reached and the nozzle chamber is subsequently ready for the ejection of another drop of ink.
FIG. 77 illustrates a side perspective view of the nozzle arrangement FIG. 78 illustrates sectional view through an array of nozzle arrangement of FIG. 77. In these figures, the numbering of elements previously introduced has been retained.
Firstly, the actuator 8 includes a series of tapered actuator units eg. 15 which comprise an upper glass portion (amorphous silicon dioxide) 16 formed on top of a titanium nitride layer 17. Alternatively a copper nickel alloy layer (hereinafter called cupronickel) can be utilized which will have a higher bend efficiency where bend efficiency is defined as:




  
    bend
    ⁢
    
      
    
    ⁢
    efficiency
  
  =
  
    
      
        Young
        '
      
      ⁢
      s
      ⁢
      
        
      
      ⁢
      Modulus
      ×
      
        (
        
          Coefficient
          ⁢
          
            
          
          ⁢
          of
          ⁢
          
            
          
          ⁢
          thermal
          ⁢
          
            
          
          ⁢
          Expansion
        
        )
      
    
    
      
        Density
        ×
        Specific
        ⁢
        
          
        
        ⁢
        Heat
        ⁢
        
          
        
        ⁢
        Capacity
      
      ⁢
      
        
      
    
  




The titanium nitride layer 17 is in a tapered form and, as such, resistive heating takes place near an end portion of the post 10. Adjacent titanium nitride/glass portions 15 are interconnected at a block portion 19 which also provides a mechanical structural support for the actuator 8.
The heater means 9 ideally includes a plurality of the tapered actuator unit 15 which are elongate and spaced apart such that, upon heating, the bending force exhibited along the axis of the actuator 8 is maximized. Slots are defined between adjacent tapered units 15 and allow for slight differential operation of each actuator 8 with respect to adjacent actuators 8.
The block portion 19 is interconnected to an arm 20. The arm 20 is in turn connected to the paddle 7 inside the nozzle chamber 1 by means of a slot e.g. 22 formed in the side of the nozzle chamber 1. The slot 22 is designed generally to mate with the surfaces of the arm 20 so as to minimize opportunities for the outflow of ink around the arm 20. The ink is held generally within the nozzle chamber 1 via surface tension effects around the slot 22.
When it is desired to actuate the arm 20, a conductive current is passed through the titanium nitride layer 17 via vias within the block portion 19 connecting to a lower CMOS layer 6 which provides the necessary power and control circuitry for the nozzle arrangement. The conductive current results in heating of the nitride layer 17 adjacent to the post 10 which results in a general upward bending of the arm 20 and consequential ejection of ink out of the nozzle 4. The ejected drop is printed on a page in the usual manner for an inkjet printer as previously described.
An array of nozzle arrangements can be formed so as to create a single printhead. For example, in FIG. 78 there is illustrated a partly sectioned various array view which comprises multiple ink ejection nozzle arrangements of FIG. 77 laid out in interleaved lines so as to form a printhead array. Of course, different types of arrays can be formulated including fill color arrays etc.
Fabrication of the inkjet nozzle arrangement is indicated in FIGS. 80 to 89. The preferred embodiment achieves a particular balance between utilization of the standard semi-conductor processing material such as titanium nitride and glass in a MEMS process. Obviously the skilled person may make other choices of materials and design features where the economics are justified. For example, a copper nickel alloy of 50% copper and 50% nickel may be more advantageously deployed as the conductive heating compound as it is likely to have higher levels of bend efficiency. Also, other design structures may be employed where it is not necessary to provide for such a simple form of manufacture.
The presently disclosed ink jet printing technology is potentially suited to a wide range of printing system including: colour and monochrome office printers, short run digital printers, high speed digital printers, offset press supplemental printers, low cost scanning printers high speed pagewidth printers, notebook computers with inbuilt pagewidth printers, portable colour and monochrome printers, colour and monochrome copiers, colour and monochrome facsimile machines, combined printer, facsimile and copying machines, label printers, large format plotters, photograph copiers, printers for digital photographic “minilabs”, video printers, PHOTO CD (PHOTO CD is a registered trade mark of the Eastman Kodak Company) printers, portable printers for PDAs, wallpaper printers, indoor sign printers, billboard printers, fabric printers, camera printers and fault tolerant commercial printer arrays. Of these applications, the printing of wallpaper will now be described in detail below.
Other Inkjet Technologies
The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable.
The most significant problem with thermal ink jet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.
The most significant problem with piezoelectric ink jet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per printhead, but is a major impediment to the fabrication of pagewidth printheads with 19,200 nozzles.
Ideally, the ink jet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new inkjet technologies have been created. The target features include:
low power (less than 10 Watts)
high resolution capability (1,600 dpi or more)
photographic quality output
low manufacturing cost
small size (pagewidth times minimum cross section)
high speed (<2 seconds per page).
All of these features can be met or exceeded by the ink jet systems described below with differing levels of difficulty. Forty-five different ink jet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table under the heading Cross References to Related Applications.
The ink jet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems.
For ease of manufacture using standard process equipment, the printhead is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the printhead is 100 mm long, with a width which depends upon the ink jet type. The smallest printhead designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The printheads each contain 19,200 nozzles plus data and control circuitry.
Ink is supplied to the back of the printhead by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The printhead is connected to the camera circuitry by tape automated bonding.
Tables of Drop-on-Demand Ink Jets
Eleven important characteristics of the fundamental operation of individual ink jet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee.
The following tables form the axes of an eleven dimensional table of ink jet types.
Actuator mechanism (18 types)
Basic operation mode (7 types)
Auxiliary mechanism (8 types)
Actuator amplification or modification method (17 types)
Actuator motion (19 types)
Nozzle refill method (4 types)
Method of restricting back-flow through inlet (10 types)
Nozzle clearing method (9 types)
Nozzle plate construction (9 types)
Drop ejection direction (5 types)
Ink type (7 types)
The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of ink jet nozzle. While not all of the possible combinations result in a viable ink jet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain ink jet types have been investigated in detail. These are designated IJ01 to IJ45 above which matches the docket numbers in the table under the heading Cross References to Related Applications.
Other ink jet configurations can readily be derived from these forty-five examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into ink jet printheads with characteristics superior to any currently available ink jet technology.
Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, print technology may be listed more than once in a table, where it shares characteristics with more than one entry.
Suitable applications for the ink jet technologies include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc.
The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.










Actuator mechanism (applied only to selected ink drops)












Description
Advantages
Disadvantages
Examples





Thermal
An electrothermal
Large force
High power
Canon Bubblejet


bubble
heater heats the ink to
generated
Ink carrier
1979 Endo et al GB



above boiling point,
Simple
limited to water
patent 2,007,162



transferring significant
construction
Low efficiency
Xerox heater-in-



heat to the aqueous
No moving parts
High
pit 1990 Hawkins et



ink. A bubble
Fast operation
temperatures
al U.S. Pat. No. 4,899,181



nucleates and quickly
Small chip area
required
Hewlett-Packard



forms, expelling the
required for actuator
High mechanical
TIJ 1982 Vaught et



ink.

stress
al U.S. Pat. No. 4,490,728



The efficiency of the

Unusual



process is low, with

materials required



typically less than

Large drive



0.05% of the electrical

transistors



energy being

Cavitation causes



transformed into

actuator failure



kinetic energy of the

Kogation reduces



drop.

bubble formation





Large print heads





are difficult to





fabricate


Piezoelectric
A piezoelectric crystal
Low power
Very large area
Kyser et al U.S. Pat. No.



such as lead
consumption
required for actuator
3,946,398



lanthanum zirconate
Many ink types
Difficult to
Zoltan U.S. Pat. No.



(PZT) is electrically
can be used
integrate with
3,683,212



activated, and either
Fast operation
electronics
1973 Stemme



expands, shears, or
High efficiency
High voltage
U.S. Pat. No. 3,747,120



bends to apply

drive transistors
Epson Stylus



pressure to the ink,

required
Tektronix



ejecting drops.

Full pagewidth
IJ04





print heads





impractical due to





actuator size





Requires





electrical poling in





high field strengths





during manufacture


Electrostrictive
An electric field is
Low power
Low maximum
Seiko Epson,



used to activate
consumption
strain (approx.
Usui et all JP



electrostriction in
Many ink types
0.01%)
253401/96



relaxor materials such
can be used
Large area
IJ04



as lead lanthanum
Low thermal
required for actuator



zirconate titanate
expansion
due to low strain



(PLZT) or lead
Electric field
Response speed



magnesium niobate
strength required
is marginal (~10 μs)



(PMN).
(approx. 3.5 V/μm)
High voltage




can be generated
drive transistors




without difficulty
required




Does not require
Full pagewidth




electrical poling
print heads





impractical due to





actuator size


Ferroelectric
An electric field is
Low power
Difficult to
IJ04



used to induce a phase
consumption
integrate with



transition between the
Many ink types
electronics



antiferroelectric (AFE)
can be used
Unusual



and ferroelectric (FE)
Fast operation
materials such as



phase. Perovskite
(<1 μs)
PLZSnT are



materials such as tin
Relatively high
required



modified lead
longitudinal strain
Actuators require



lanthanum zirconate
High efficiency
a large area



titanate (PLZSnT)
Electric field



exhibit large strains of
strength of around 3 V/μm



up to 1% associated
can be readily



with the AFE to FE
provided



phase transition.


Electrostatic
Conductive plates are
Low power
Difficult to
IJ02, IJ04


plates
separated by a
consumption
operate electrostatic



compressible or fluid
Many ink types
devices in an



dielectric (usually air).
can be used
aqueous



Upon application of a
Fast operation
environment



voltage, the plates

The electrostatic



attract each other and

actuator will



displace ink, causing

normally need to be



drop ejection. The

separated from the



conductive plates may

ink



be in a comb or

Very large area



honeycomb structure,

required to achieve



or stacked to increase

high forces



the surface area and

High voltage



therefore the force.

drive transistors





may be required





Full pagewidth





print heads are not





competitive due to





actuator size


Electrostatic
A strong electric field
Low current
High voltage
1989 Saito et al,


pull
is applied to the ink,
consumption
required
U.S. Pat. No. 4,799,068


on ink
whereupon
Low temperature
May be damaged
1989 Miura et al,



electrostatic attraction

by sparks due to air
U.S. Pat. No. 4,810,954



accelerates the ink

breakdown
Tone-jet



towards the print

Required field



medium.

strength increases as





the drop size





decreases





High voltage





drive transistors





required





Electrostatic field





attracts dust


Permanent
An electromagnet
Low power
Complex
IJ07, IJ10


magnet
directly attracts a
consumption
fabrication


electromagnetic
permanent magnet,
Many ink types
Permanent



displacing ink and
can be used
magnetic material



causing drop ejection.
Fast operation
such as Neodymium



Rare earth magnets
High efficiency
Iron Boron (NdFeB)



with a field strength
Easy extension
required.



around 1 Tesla can be
from single nozzles
High local



used. Examples are:
to pagewidth print
currents required



Samarium Cobalt
heads
Copper



(SaCo) and magnetic

metalization should



materials in the

be used for long



neodymium iron boron

electromigration



family (NdFeB,

lifetime and low



NdDyFeBNb,

resistivity



NdDyFeB, etc)

Pigmented inks





are usually





infeasible





Operating





temperature limited





to the Curie





temperature (around





540 K)


Soft
A solenoid induced a
Low power
Complex
IJ01, IJ05, IJ08,


magnetic
magnetic field in a soft
consumption
fabrication
IJ10, IJ12, IJ14,


core electromagnetic
magnetic core or yoke
Many ink types
Materials not
IJ15, IJ17



fabricated from a
can be used
usually present in a



ferrous material such
Fast operation
CMOS fab such as



as electroplated iron
High efficiency
NiFe, CoNiFe, or



alloys such as CoNiFe
Easy extension
CoFe are required



[1], CoFe, or NiFe
from single nozzles
High local



alloys. Typically, the
to pagewidth print
currents required



soft magnetic material
heads
Copper



is in two parts, which

metalization should



are normally held

be used for long



apart by a spring.

electromigration



When the solenoid is

lifetime and low



actuated, the two parts

resistivity



attract, displacing the

Electroplating is



ink.

required





High saturation





flux density is





required (2.0-2.1 T





is achievable with





CoNiFe [1])


Lorenz
The Lorenz force
Low power
Force acts as a
IJ06, IJ11, IJ13,


force
acting on a current
consumption
twisting motion
IJ16



carrying wire in a
Many ink types
Typically, only a



magnetic field is
can be used
quarter of the



utilized.
Fast operation
solenoid length



This allows the
High efficiency
provides force in a



magnetic field to be
Easy extension
useful direction



supplied externally to
from single nozzles
High local



the print head, for
to pagewidth print
currents required



example with rare
heads
Copper



earth permanent

metalization should



magnets.

be used for long



Only the current

electromigration



carrying wire need be

lifetime and low



fabricated on the print-

resistivity



head, simplifying

Pigmented inks



materials

are usually



requirements.

infeasible


Magnetostriction
The actuator uses the
Many ink types
Force acts as a
Fischenbeck,



giant magnetostrictive
can be used
twisting motion
U.S. Pat. No. 4,032,929



effect of materials
Fast operation
Unusual
IJ25



such as Terfenol-D (an
Easy extension
materials such as



alloy of terbium,
from single nozzles
Terfenol-D are



dysprosium and iron
to pagewidth print
required



developed at the Naval
heads
High local



Ordnance Laboratory,
High force is
currents required



hence Ter-Fe-NOL).
available
Copper



For best efficiency, the

metalization should



actuator should be pre-stressed

be used for long



to approx. 8

electromigration



MPa.

lifetime and low





resistivity





Pre-stressing





may be required


Surface
Ink under positive
Low power
Requires
Silverbrook, EP


tension
pressure is held in a
consumption
supplementary force
0771 658 A2 and


reduction
nozzle by surface
Simple
to effect drop
related patent



tension. The surface
construction
separation
applications



tension of the ink is
No unusual
Requires special



reduced below the
materials required in
ink surfactants



bubble threshold,
fabrication
Speed may be



causing the ink to
High efficiency
limited by surfactant



egress from the
Easy extension
properties



nozzle.
from single nozzles




to pagewidth print




heads


Viscosity
The ink viscosity is
Simple
Requires
Silverbrook, EP


reduction
locally reduced to
construction
supplementary force
0771 658 A2 and



select which drops are
No unusual
to effect drop
related patent



to be ejected. A
materials required in
separation
applications



viscosity reduction can
fabrication
Requires special



be achieved
Easy extension
ink viscosity



electrothermally with
from single nozzles
properties



most inks, but special
to pagewidth print
High speed is



inks can be engineered
heads
difficult to achieve



for a 100:1 viscosity

Requires



reduction.

oscillating ink





pressure





A high





temperature





difference (typically





80 degrees) is





required


Acoustic
An acoustic wave is
Can operate
Complex drive
1993 Hadimioglu



generated and
without a nozzle
circuitry
et al, EUP 550,192



focussed upon the
plate
Complex
1993 Elrod et al,



drop ejection region.

fabrication
EUP 572,220





Low efficiency





Poor control of





drop position





Poor control of





drop volume


Thermoelastic
An actuator which
Low power
Efficient aqueous
IJ03, IJ09, IJ17,


bend
relies upon differential
consumption
operation requires a
IJ18, IJ19, IJ20,


actuator
thermal expansion
Many ink types
thermal insulator on
IJ21, IJ22, IJ23,



upon Joule heating is
can be used
the hot side
IJ24, IJ27, IJ28,



used.
Simple planar
Corrosion
IJ29, IJ30, IJ31,




fabrication
prevention can be
IJ32, IJ33, IJ34,




Small chip area
difficult
IJ35, IJ36, IJ37,




required for each
Pigmented inks
IJ38, IJ39, IJ40,




actuator
may be infeasible,
IJ41




Fast operation
as pigment particles




High efficiency
may jam the bend




CMOS
actuator




compatible voltages




and currents




Standard MEMS




processes can be




used




Easy extension




from single nozzles




to pagewidth print




heads


High CTE
A material with a very
High force can
Requires special
IJ09, IJ17, IJ18,


thermoelastic
high coefficient of
be generated
material (e.g. PTFE)
IJ20, IJ21, IJ22,


actuator
thermal expansion
Three methods of
Requires a PTFE
IJ23, IJ24, IJ27,



(CTE) such as
PTFE deposition are
deposition process,
IJ28, IJ29, IJ30,



polytetrafluoroethylene
under development:
which is not yet
IJ31, IJ42, IJ43,



(PTFE) is used. As
chemical vapor
standard in ULSI
IJ44



high CTE materials
deposition (CVD),
fabs



are usually non-
spin coating, and
PTFE deposition



conductive, a heater
evaporation
cannot be followed



fabricated from a
PTFE is a
with high



conductive material is
candidate for low
temperature (above



incorporated. A 50 μm
dielectric constant
350° C.) processing



long PTFE bend
insulation in ULSI
Pigmented inks



actuator with
Very low power
may be infeasible,



polysilicon heater and
consumption
as pigment particles



15 mW power input
Many ink types
may jam the bend



can provide 180 μN
can be used
actuator



force and 10 μm
Simple planar



deflection. Actuator
fabrication



motions include:
Small chip area



Bend
required for each



Push
actuator



Buckle
Fast operation



Rotate
High efficiency




CMOS




compatible voltages




and currents




Easy extension




from single nozzles




to pagewidth print




heads


Conduct-ive
A polymer with a high
High force can
Requires special
IJ24


polymer
coefficient of thermal
be generated
materials


thermoelastic
expansion (such as
Very low power
development (High


actuator
PTFE) is doped with
consumption
CTE conductive



conducting substances
Many ink types
polymer)



to increase its
can be used
Requires a PTFE



conductivity to about 3
Simple planar
deposition process,



orders of magnitude
fabrication
which is not yet



below that of copper.
Small chip area
standard in ULSI



The conducting
required for each
fabs



polymer expands
actuator
PTFE deposition



when resistively
Fast operation
cannot be followed



heated.
High efficiency
with high



Examples of
CMOS
temperature (above



conducting dopants
compatible voltages
350° C.) processing



include:
and currents
Evaporation and



Carbon nanotubes
Easy extension
CVD deposition



Metal fibers
from single nozzles
techniques cannot



Conductive polymers
to pagewidth print
be used



such as doped
heads
Pigmented inks



polythiophene

may be infeasible,



Carbon granules

as pigment particles





may jam the bend





actuator


Shape
A shape memory alloy
High force is
Fatigue limits
IJ26


memory
such as TiNi (also
available (stresses
maximum number


alloy
known as Nitinol -
of hundreds of MPa)
of cycles



Nickel Titanium alloy
Large strain is
Low strain (1%)



developed at the Naval
available (more than
is required to extend



Ordnance Laboratory)
3%)
fatigue resistance



is thermally switched
High corrosion
Cycle rate



between its weak
resistance
limited by heat



martensitic state and
Simple
removal



its high stiffness
construction
Requires unusual



austenic state. The
Easy extension
materials (TiNi)



shape of the actuator
from single nozzles
The latent heat of



in its martensitic state
to pagewidth print
transformation must



is deformed relative to
heads
be provided



the austenic shape.
Low voltage
High current



The shape change
operation
operation



causes ejection of a

Requires pre-



drop.

stressing to distort





the martensitic state


Linear
Linear magnetic
Linear Magnetic
Requires unusual
IJ12


Magnetic
actuators include the
actuators can be
semiconductor


Actuator
Linear Induction
constructed with
materials such as



Actuator (LIA), Linear
high thrust, long
soft magnetic alloys



Permanent Magnet
travel, and high
(e.g. CoNiFe)



Synchronous Actuator
efficiency using
Some varieties



(LPMSA), Linear
planar
also require



Reluctance
semiconductor
permanent magnetic



Synchronous Actuator
fabrication
materials such as



(LRSA), Linear
techniques
Neodymium iron



Switched Reluctance
Long actuator
boron (NdFeB)



Actuator (LSRA), and
travel is available
Requires



the Linear Stepper
Medium force is
complex multi-



Actuator (LSA).
available
phase drive circuitry




Low voltage
High current




operation
operation



















Basic operation mode












Description
Advantages
Disadvantages
Examples





Actuator
This is the simplest
Simple operation
Drop repetition
Thermal ink jet


directly
mode of operation: the
No external
rate is usually
Piezoelectric ink


pushes ink
actuator directly
fields required
limited to around 10 kHz.
jet



supplies sufficient
Satellite drops
However, this
IJ01, IJ02, IJ03,



kinetic energy to expel
can be avoided if
is not fundamental
IJ04, IJ05, IJ06,



the drop. The drop
drop velocity is less
to the method, but is
IJ07, IJ09, IJ11,



must have a sufficient
than 4 m/s
related to the refill
IJ12, IJ14, IJ16,



velocity to overcome
Can be efficient,
method normally
IJ20, IJ22, IJ23,



the surface tension.
depending upon the
used
IJ24, IJ25, IJ26,




actuator used
All of the drop
IJ27, IJ28, IJ29,





kinetic energy must
IJ30, IJ31, IJ32,





be provided by the
IJ33, IJ34, IJ35,





actuator
IJ36, IJ37, IJ38,





Satellite drops
IJ39, IJ40, IJ41,





usually form if drop
IJ42, IJ43, IJ44





velocity is greater





than 4.5 m/s


Proximity
The drops to be
Very simple print
Requires close
Silverbrook, EP



printed are selected by
head fabrication can
proximity between
0771 658 A2 and



some manner (e.g.
be used
the print head and
related patent



thermally induced
The drop
the print media or
applications



surface tension
selection means
transfer roller



reduction of
does not need to
May require two



pressurized ink).
provide the energy
print heads printing



Selected drops are
required to separate
alternate rows of the



separated from the ink
the drop from the
image



in the nozzle by
nozzle
Monolithic color



contact with the print

print heads are



medium or a transfer

difficult



roller.


Electrostatic
The drops to be
Very simple print
Requires very
Silverbrook, EP


pull
printed are selected by
head fabrication can
high electrostatic
0771 658 A2 and


on ink
some manner (e.g.
be used
field
related patent



thermally induced
The drop
Electrostatic field
applications



surface tension
selection means
for small nozzle
Tone-Jet



reduction of
does not need to
sizes is above air



pressurized ink).
provide the energy
breakdown



Selected drops are
required to separate
Electrostatic field



separated from the ink
the drop from the
may attract dust



in the nozzle by a
nozzle



strong electric field.


Magnetic
The drops to be
Very simple print
Requires
Silverbrook, EP


pull on ink
printed are selected by
head fabrication can
magnetic ink
0771 658 A2 and



some manner (e.g.
be used
Ink colors other
related patent



thermally induced
The drop
than black are
applications



surface tension
selection means
difficult



reduction of
does not need to
Requires very



pressurized ink).
provide the energy
high magnetic fields



Selected drops are
required to separate



separated from the ink
the drop from the



in the nozzle by a
nozzle



strong magnetic field



acting on the magnetic



ink.


Shutter
The actuator moves a
High speed (>50 kHz)
Moving parts are
IJ13, IJ17, IJ21



shutter to block ink
operation can
required



flow to the nozzle. The
be achieved due to
Requires ink



ink pressure is pulsed
reduced refill time
pressure modulator



at a multiple of the
Drop timing can
Friction and wear



drop ejection
be very accurate
must be considered



frequency.
The actuator
Stiction is




energy can be very
possible




low


Shuttered
The actuator moves a
Actuators with
Moving parts are
IJ08, IJ15, IJ18,


grill
shutter to block ink
small travel can be
required
IJ19



flow through a grill to
used
Requires ink



the nozzle. The shutter
Actuators with
pressure modulator



movement need only
small force can be
Friction and wear



be equal to the width
used
must be considered



of the grill holes.
High speed (>50 kHz)
Stiction is




operation can
possible




be achieved


Pulsed
A pulsed magnetic
Extremely low
Requires an
IJ10


magnetic
field attracts an ‘ink
energy operation is
external pulsed


pull on ink
pusher’ at the drop
possible
magnetic field


pusher
ejection frequency. An
No heat
Requires special



actuator controls a
dissipation
materials for both



catch, which prevents
problems
the actuator and the



the ink pusher from

ink pusher



moving when a drop is

Complex



not to be ejected.

construction



















Auxiliary mechanism (applied to all nozzles)












Description
Advantages
Disadvantages
Examples





None
The actuator directly
Simplicity of
Drop ejection
Most ink jets,



fires the ink drop, and
construction
energy must be
including



there is no external
Simplicity of
supplied by
piezoelectric and



field or other
operation
individual nozzle
thermal bubble.



mechanism required.
Small physical
actuator
IJ01, IJ02, IJ03,




size

IJ04, IJ05, IJ07,






IJ09, IJ11, IJ12,






IJ14, IJ20, IJ22,






IJ23, IJ24, IJ25,






IJ26, IJ27, IJ28,






IJ29, IJ30, IJ31,






IJ32, IJ33, IJ34,






IJ35, IJ36, IJ37,






IJ38, IJ39, IJ40,






IJ41, IJ42, IJ43,






IJ44


Oscillating
The ink pressure
Oscillating ink
Requires external
Silverbrook, EP


ink pressure
oscillates, providing
pressure can provide
ink pressure
0771 658 A2 and


(including
much of the drop
a refill pulse,
oscillator
related patent


acoustic
ejection energy. The
allowing higher
Ink pressure
applications


stimulation)
actuator selects which
operating speed
phase and amplitude
IJ08, IJ13, IJ15,



drops are to be fired
The actuators
must be carefully
IJ17, IJ18, IJ19,



by selectively
may operate with
controlled
IJ21



blocking or enabling
much lower energy
Acoustic



nozzles. The ink
Acoustic lenses
reflections in the ink



pressure oscillation
can be used to focus
chamber must be



may be achieved by
the sound on the
designed for



vibrating the print
nozzles



head, or preferably by



an actuator in the ink



supply.


Media
The print head is
Low power
Precision
Silverbrook, EP


proximity
placed in close
High accuracy
assembly required
0771 658 A2 and



proximity to the print
Simple print head
Paper fibers may
related patent



medium. Selected
construction
cause problems
applications



drops protrude from

Cannot print on



the print head further

rough substrates



than unselected drops,



and contact the print



medium. The drop



soaks into the medium



fast enough to cause



drop separation.


Transfer
Drops are printed to a
High accuracy
Bulky
Silverbrook, EP


roller
transfer roller instead
Wide range of
Expensive
0771 658 A2 and



of straight to the print
print substrates can
Complex
related patent



medium. A transfer
be used
construction
applications



roller can also be used
Ink can be dried

Tektronix hot



for proximity drop
on the transfer roller

melt piezoelectric



separation.


ink jet






Any of the IJ






series


Electrostatic
An electric field is
Low power
Field strength
Silverbrook, EP



used to accelerate
Simple print head
required for
0771 658 A2 and



selected drops towards
construction
separation of small
related patent



the print medium.

drops is near or
applications





above air
Tone-Jet





breakdown


Direct
A magnetic field is
Low power
Requires
Silverbrook, EP


magnetic
used to accelerate
Simple print head
magnetic ink
0771 658 A2 and


field
selected drops of
construction
Requires strong
related patent



magnetic ink towards

magnetic field
applications



the print medium.


Cross
The print head is
Does not require
Requires external
IJ06, IJ16


magnetic
placed in a constant
magnetic materials
magnet


field
magnetic field. The
to be integrated in
Current densities



Lorenz force in a
the print head
may be high,



current carrying wire
manufacturing
resulting in



is used to move the
process
electromigration



actuator.

problems


Pulsed
A pulsed magnetic
Very low power
Complex print
IJ10


magnetic
field is used to
operation is possible
head construction


field
cyclically attract a
Small print head
Magnetic



paddle, which pushes
size
materials required in



on the ink. A small

print head



actuator moves a



catch, which



selectively prevents



the paddle from



moving.



















Actuator amplification or modification method












Description
Advantages
Disadvantages
Examples





None
No actuator
Operational
Many actuator
Thermal Bubble



mechanical
simplicity
mechanisms have
Ink jet



amplification is used.

insufficient travel,
IJ01, IJ02, IJ06,



The actuator directly

or insufficient force,
IJ07, IJ16, IJ25,



drives the drop

to efficiently drive
IJ26



ejection process.

the drop ejection





process


Differential
An actuator material
Provides greater
High stresses are
Piezoelectric


expansion
expands more on one
travel in a reduced
involved
IJ03, IJ09, IJ17,


bend
side than on the other.
print head area
Care must be
IJ18, IJ19, IJ20,


actuator
The expansion may be

taken that the
IJ21, IJ22, IJ23,



thermal, piezoelectric,

materials do not
IJ24, IJ27, IJ29,



magnetostrictive, or

delaminate
IJ30, IJ31, IJ32,



other mechanism. The

Residual bend
IJ33, IJ34, IJ35,



bend actuator converts

resulting from high
IJ36, IJ37, IJ38,



a high force low travel

temperature or high
IJ39, IJ42, IJ43,



actuator mechanism to

stress during
IJ44



high travel, lower

formation



force mechanism.


Transient
A trilayer bend
Very good
High stresses are
IJ40, IJ41


bend
actuator where the two
temperature stability
involved


actuator
outside layers are
High speed, as a
Care must be



identical. This cancels
new drop can be
taken that the



bend due to ambient
fired before heat
materials do not



temperature and
dissipates
delaminate



residual stress. The
Cancels residual



actuator only responds
stress of formation



to transient heating of



one side or the other.


Reverse
The actuator loads a
Better coupling
Fabrication
IJ05, IJ11


spring
spring. When the
to the ink
complexity



actuator is turned off,

High stress in the



the spring releases.

spring



This can reverse the



force/distance curve of



the actuator to make it



compatible with the



force/time



requirements of the



drop ejection.


Actuator
A series of thin
Increased travel
Increased
Some


stack
actuators are stacked.
Reduced drive
fabrication
piezoelectric ink jets



This can be
voltage
complexity
IJ04



appropriate where

Increased



actuators require high

possibility of short



electric field strength,

circuits due to



such as electrostatic

pinholes



and piezoelectric



actuators.


Multiple
Multiple smaller
Increases the
Actuator forces
IJ12, IJ13, IJ18,


actuators
actuators are used
force available from
may not add
IJ20, IJ22, IJ28,



simultaneously to
an actuator
linearly, reducing
IJ42, IJ43



move the ink. Each
Multiple
efficiency



actuator need provide
actuators can be



only a portion of the
positioned to control



force required.
ink flow accurately


Linear
A linear spring is used
Matches low
Requires print
IJ15


Spring
to transform a motion
travel actuator with
head area for the



with small travel and
higher travel
spring



high force into a
requirements



longer travel, lower
Non-contact



force motion.
method of motion




transformation


Coiled
A bend actuator is
Increases travel
Generally
IJ17, IJ21, IJ34,


actuator
coiled to provide
Reduces chip
restricted to planar
IJ35



greater travel in a
area
implementations



reduced chip area.
Planar
due to extreme




implementations are
fabrication difficulty




relatively easy to
in other orientations.




fabricate.


Flexure
A bend actuator has a
Simple means of
Care must be
IJ10, IJ19, IJ33


bend
small region near the
increasing travel of
taken not to exceed


actuator
fixture point, which
a bend actuator
the elastic limit in



flexes much more

the flexure area



readily than the

Stress



remainder of the

distribution is very



actuator. The actuator

uneven



flexing is effectively

Difficult to



converted from an

accurately model



even coiling to an

with finite element



angular bend, resulting

analysis



in greater travel of the



actuator tip.


Catch
The actuator controls a
Very low
Complex
IJ10



small catch. The catch
actuator energy
construction



either enables or
Very small
Requires external



disables movement of
actuator size
force



an ink pusher that is

Unsuitable for



controlled in a bulk

pigmented inks



manner.


Gears
Gears can be used to
Low force, low
Moving parts are
IJ13



increase travel at the
travel actuators can
required



expense of duration.
be used
Several actuator



Circular gears, rack
Can be fabricated
cycles are required



and pinion, ratchets,
using standard
More complex



and other gearing
surface MEMS
drive electronics



methods can be used.
processes
Complex





construction





Friction, friction,





and wear are





possible


Buckle plate
A buckle plate can be
Very fast
Must stay within
S. Hirata et al,



used to change a slow
movement
elastic limits of the
“An Ink-jet Head



actuator into a fast
achievable
materials for long
Using Diaphragm



motion. It can also

device life
Microactuator”,



convert a high force,

High stresses
Proc. IEEE MEMS,



low travel actuator

involved
February 1996, pp



into a high travel,

Generally high
418-423.



medium force motion.

power requirement
IJ18, IJ27


Tapered
A tapered magnetic
Linearizes the
Complex
IJ14


magnetic
pole can increase
magnetic
construction


pole
travel at the expense
force/distance curve



of force.


Lever
A lever and fulcrum is
Matches low
High stress
IJ32, IJ36, 1J37



used to transform a
travel actuator with
around the fulcrum



motion with small
higher travel



travel and high force
requirements



into a motion with
Fulcrum area has



longer travel and
no linear movement,



lower force. The lever
and can be used for



can also reverse the
a fluid seal



direction of travel.


Rotary
The actuator is
High mechanical
Complex
IJ28


impeller
connected to a rotary
advantage
construction



impeller. A small
The ratio of force
Unsuitable for



angular deflection of
to travel of the
pigmented inks



the actuator results in
actuator can be



a rotation of the
matched to the



impeller vanes, which
nozzle requirements



push the ink against
by varying the



stationary vanes and
number of impeller



out of the nozzle.
vanes


Acoustic
A refractive or
No moving parts
Large area
1993 Hadimioglu


lens
diffractive (e.g. zone

required
et al, EUP 550,192



plate) acoustic lens is

Only relevant for
1993 Elrod et al,



used to concentrate

acoustic ink jets
EUP 572,220



sound waves.


Sharp
A sharp point is used
Simple
Difficult to
Tone-jet


conductive
to concentrate an
construction
fabricate using


point
electrostatic field.

standard VLSI





processes for a





surface ejecting ink-





jet





Only relevant for





electrostatic ink jets



















Actuator motion












Description
Advantages
Disadvantages
Examples





Volume
The volume of the
Simple
High energy is
Hewlett-Packard


expansion
actuator changes,
construction in the
typically required to
Thermal Ink jet



pushing the ink in all
case of thermal ink
achieve volume
Canon Bubblejet



directions.
jet
expansion. This





leads to thermal





stress, cavitation,





and kogation in





thermal ink jet





implementations


Linear,
The actuator moves in
Efficient
High fabrication
IJ01, IJ02, IJ04,


normal to
a direction normal to
coupling to ink
complexity may be
IJ07, IJ11, IJ14


chip surface
the print head surface.
drops ejected
required to achieve



The nozzle is typically
normal to the
perpendicular



in the line of
surface
motion



movement.


Parallel to
The actuator moves
Suitable for
Fabrication
IJ12, IJ13, IJ15,


chip surface
parallel to the print
planar fabrication
complexity
IJ33, , IJ34, IJ35,



head surface. Drop

Friction
IJ36



ejection may still be

Stiction



normal to the surface.


Membrane
An actuator with a
The effective
Fabrication
1982 Howkins


push
high force but small
area of the actuator
complexity
U.S. Pat. No. 4,459,601



area is used to push a
becomes the
Actuator size



stiff membrane that is
membrane area
Difficulty of



in contact with the ink.

integration in a





VLSI process


Rotary
The actuator causes
Rotary levers
Device
IJ05, IJ08, IJ13,



the rotation of some
may be used to
complexity
IJ28



element, such a grill or
increase travel
May have



impeller
Small chip area
friction at a pivot




requirements
point


Bend
The actuator bends
A very small
Requires the
1970 Kyser et al



when energized. This
change in
actuator to be made
U.S. Pat. No. 3,946,398



may be due to
dimensions can be
from at least two
1973 Stemme



differential thermal
converted to a large
distinct layers, or to
U.S. Pat. No. 3,747,120



expansion,
motion.
have a thermal
IJ03, IJ09, IJ10,



piezoelectric

difference across the
IJ19, IJ23, IJ24,



expansion,

actuator
IJ25, IJ29, IJ30,



magnetostriction, or


IJ31, IJ33, IJ34,



other form of relative


IJ35



dimensional change.


Swivel
The actuator swivels
Allows operation
Inefficient
IJ06



around a central pivot.
where the net linear
coupling to the ink



This motion is suitable
force on the paddle
motion



where there are
is zero



opposite forces
Small chip area



applied to opposite
requirements



sides of the paddle,



e.g. Lorenz force.


Straighten
The actuator is
Can be used with
Requires careful
IJ26, IJ32



normally bent, and
shape memory
balance of stresses



straightens when
alloys where the
to ensure that the



energized.
austenic phase is
quiescent bend is




planar
accurate


Double
The actuator bends in
One actuator can
Difficult to make
IJ36, IJ37, IJ38


bend
one direction when
be used to power
the drops ejected by



one element is
two nozzles.
both bend directions



energized, and bends
Reduced chip
identical.



the other way when
size.
A small



another element is
Not sensitive to
efficiency loss



energized.
ambient temperature
compared to





equivalent single





bend actuators.


Shear
Energizing the
Can increase the
Not readily
1985 Fishbeck



actuator causes a shear
effective travel of
applicable to other
U.S. Pat. No. 4,584,590



motion in the actuator
piezoelectric
actuator



material.
actuators
mechanisms


Radial constriction
The actuator squeezes
Relatively easy
High force
1970 Zoltan U.S. Pat. No.



an ink reservoir,
to fabricate single
required
3,683,212



forcing ink from a
nozzles from glass
Inefficient



constricted nozzle.
tubing as
Difficult to




macroscopic
integrate with VLSI




structures
processes


Coil/uncoil
A coiled actuator
Easy to fabricate
Difficult to
IJ17, IJ21, IJ34,



uncoils or coils more
as a planar VLSI
fabricate for non-
IJ35



tightly. The motion of
process
planar devices



the free end of the
Small area
Poor out-of-plane



actuator ejects the ink.
required, therefore
stiffness




low cost


Bow
The actuator bows (or
Can increase the
Maximum travel
IJ16, IJ18, IJ27



buckles) in the middle
speed of travel
is constrained



when energized.
Mechanically
High force




rigid
required


Push-Pull
Two actuators control
The structure is
Not readily
IJ18



a shutter. One actuator
pinned at both ends,
suitable for ink jets



pulls the shutter, and
so has a high out-of-
which directly push



the other pushes it.
plane rigidity
the ink


Curl
A set of actuators curl
Good fluid flow
Design
IJ20, IJ42


inwards
inwards to reduce the
to the region behind
complexity



volume of ink that
the actuator



they enclose.
increases efficiency


Curl
A set of actuators curl
Relatively simple
Relatively large
IJ43


outwards
outwards, pressurizing
construction
chip area



ink in a chamber



surrounding the



actuators, and



expelling ink from a



nozzle in the chamber.


Iris
Multiple vanes enclose
High efficiency
High fabrication
IJ22



a volume of ink. These
Small chip area
complexity



simultaneously rotate,

Not suitable for



reducing the volume

pigmented inks



between the vanes.


Acoustic
The actuator vibrates
The actuator can
Large area
1993 Hadimioglu


vibration
at a high frequency.
be physically distant
required for
et al, EUP 550,192




from the ink
efficient operation
1993 Elrod et al,





at useful frequencies
EUP 572,220





Acoustic





coupling and





crosstalk





Complex drive





circuitry





Poor control of





drop volume and





position


None
In various ink jet
No moving parts
Various other
Silverbrook, EP



designs the actuator

tradeoffs are
0771 658 A2 and



does not move.

required to
related patent





eliminate moving
applications





parts
Tone-jet



















Nozzle refill method












Description
Advantages
Disadvantages
Examples





Surface
This is the normal way
Fabrication
Low speed
Thermal ink jet


tension
that ink jets are
simplicity
Surface tension
Piezoelectric ink



refilled. After the
Operational
force relatively
jet



actuator is energized,
simplicity
small compared to
IJ01-IJ07, IJ10-IJ14,



it typically returns

actuator force
IJ16, IJ20,



rapidly to its normal

Long refill time
IJ22-IJ45



position. This rapid

usually dominates



return sucks in air

the total repetition



through the nozzle

rate



opening. The ink



surface tension at the



nozzle then exerts a



small force restoring



the meniscus to a



minimum area. This



force refills the nozzle.


Shuttered
Ink to the nozzle
High speed
Requires
IJ08, IJ13, IJ15,


oscillating
chamber is provided at
Low actuator
common ink
IJ17, IJ18, IJ19,


ink pressure
a pressure that
energy, as the
pressure oscillator
IJ21



oscillates at twice the
actuator need only
May not be



drop ejection
open or close the
suitable for



frequency. When a
shutter, instead of
pigmented inks



drop is to be ejected,
ejecting the ink drop



the shutter is opened



for 3 half cycles: drop



ejection, actuator



return, and refill. The



shutter is then closed



to prevent the nozzle



chamber emptying



during the next



negative pressure



cycle.


Refill
After the main
High speed, as
Requires two
IJ09


actuator
actuator has ejected a
the nozzle is
independent



drop a second (refill)
actively refilled
actuators per nozzle



actuator is energized.



The refill actuator



pushes ink into the



nozzle chamber. The



refill actuator returns



slowly, to prevent its



return from emptying



the chamber again.


Positive ink
The ink is held a slight
High refill rate,
Surface spill
Silverbrook, EP


pressure
positive pressure.
therefore a high
must be prevented
0771 658 A2 and



After the ink drop is
drop repetition rate
Highly
related patent



ejected, the nozzle
is possible
hydrophobic print
applications



chamber fills quickly

head surfaces are
Alternative for:,



as surface tension and

required
IJ01-IJ07, IJ10-IJ14,



ink pressure both


IJ16, IJ20, IJ22-IJ45



operate to refill the



nozzle.



















Method of restricting back-flow through inlet












Description
Advantages
Disadvantages
Examples





Long inlet
The ink inlet channel
Design simplicity
Restricts refill
Thermal ink jet


channel
to the nozzle chamber
Operational
rate
Piezoelectric ink



is made long and
simplicity
May result in a
jet



relatively narrow,
Reduces
relatively large chip
IJ42, IJ43



relying on viscous
crosstalk
area



drag to reduce inlet

Only partially



back-flow.

effective


Positive ink
The ink is under a
Drop selection
Requires a
Silverbrook, EP


pressure
positive pressure, so
and separation
method (such as a
0771 658 A2 and



that in the quiescent
forces can be
nozzle rim or
related patent



state some of the ink
reduced
effective
applications



drop already protrudes
Fast refill time
hydrophobizing, or
Possible



from the nozzle.

both) to prevent
operation of the



This reduces the

flooding of the
following: IJ01-IJ07,



pressure in the nozzle

ejection surface of
IJ09-IJ12,



chamber which is

the print head.
IJ14, IJ16, IJ20,



required to eject a


IJ22, , IJ23-IJ34,



certain volume of ink.


IJ36-IJ41, IJ44



The reduction in



chamber pressure



results in a reduction



in ink pushed out



through the inlet.


Baffle
One or more baffles
The refill rate is
Design
HP Thermal Ink



are placed in the inlet
not as restricted as
complexity
Jet



ink flow. When the
the long inlet
May increase
Tektronix



actuator is energized,
method.
fabrication
piezoelectric ink jet



the rapid ink
Reduces
complexity (e.g.



movement creates
crosstalk
Tektronix hot melt



eddies which restrict

Piezoelectric print



the flow through the

heads).



inlet. The slower refill



process is unrestricted,



and does not result in



eddies.


Flexible flap
In this method recently
Significantly
Not applicable to
Canon


restricts
disclosed by Canon,
reduces back-flow
most ink jet


inlet
the expanding actuator
for edge-shooter
configurations



(bubble) pushes on a
thermal ink jet
Increased



flexible flap that
devices
fabrication



restricts the inlet.

complexity





Inelastic





deformation of





polymer flap results





in creep over





extended use


Inlet filter
A filter is located
Additional
Restricts refill
IJ04, IJ12, IJ24,



between the ink inlet
advantage of ink
rate
IJ27, IJ29, IJ30



and the nozzle
filtration
May result in



chamber. The filter
Ink filter may be
complex



has a multitude of
fabricated with no
construction



small holes or slots,
additional process



restricting ink flow.
steps



The filter also removes



particles which may



block the nozzle.


Small inlet
The ink inlet channel
Design simplicity
Restricts refill
IJ02, IJ37, IJ44


compared
to the nozzle chamber

rate


to nozzle
has a substantially

May result in a



smaller cross section

relatively large chip



than that of the nozzle,

area



resulting in easier ink

Only partially



egress out of the

effective



nozzle than out of the



inlet.


Inlet shutter
A secondary actuator
Increases speed
Requires separate
IJ09



controls the position of
of the ink-jet print
refill actuator and



a shutter, closing off
head operation
drive circuit



the ink inlet when the



main actuator is



energized.


The inlet is
The method avoids the
Back-flow
Requires careful
IJ01, IJ03, IJ05,


located
problem of inlet back-
problem is
design to minimize
IJ06, IJ07, IJ10,


behind the
flow by arranging the
eliminated
the negative
IJ11, IJ14, IJ16,


ink-pushing
ink-pushing surface of

pressure behind the
IJ22, IJ23, IJ25,


surface
the actuator between

paddle
IJ28, IJ31, IJ32,



the inlet and the


IJ33, IJ34, IJ35,



nozzle.


IJ36, IJ39, IJ40,






IJ41


Part of the
The actuator and a
Significant
Small increase in
IJ07, IJ20, IJ26,


actuator
wall of the ink
reductions in back-
fabrication
IJ38


moves to
chamber are arranged
flow can be
complexity


shut off the
so that the motion of
achieved


inlet
the actuator closes off
Compact designs



the inlet.
possible


Nozzle
In some configurations
Ink back-flow
None related to
Silverbrook, EP


actuator
of ink jet, there is no
problem is
ink back-flow on
0771 658 A2 and


does not
expansion or
eliminated
actuation
related patent


result in ink
movement of an


applications


back-flow
actuator which may


Valve-jet



cause ink back-flow


Tone-jet



through the inlet.



















Nozzle Clearing Method












Description
Advantages
Disadvantages
Examples





Normal
All of the nozzles are
No added
May not be
Most ink jet


nozzle firing
fired periodically,
complexity on the
sufficient to
systems



before the ink has a
print head
displace dried ink
IJ01, IJ02, IJ03,



chance to dry. When


IJ04, IJ05, IJ06,



not in use the nozzles


IJ07, IJ09, IJ10,



are sealed (capped)


IJ11, IJ12, IJ14,



against air.


IJ16, IJ20, IJ22,



The nozzle firing is


IJ23, IJ24, IJ25,



usually performed


IJ26, IJ27, IJ28,



during a special


IJ29, IJ30, IJ31,



clearing cycle, after


IJ32, IJ33, IJ34,



first moving the print


IJ36, IJ37, IJ38,



head to a cleaning


IJ39, IJ40,, IJ41,



station.


IJ42, IJ43, IJ44,,






IJ45


Extra
In systems which heat
Can be highly
Requires higher
Silverbrook, EP


power to
the ink, but do not boil
effective if the
drive voltage for
0771 658 A2 and.


ink heater
it under normal
heater is adjacent to
clearing
related patent



situations, nozzle
the nozzle
May require
applications



clearing can be

larger drive



achieved by over-

transistors



powering the heater



and boiling ink at the



nozzle.


Rapid
The actuator is fired in
Does not require
Effectiveness
May be used


success-ion
rapid succession. In
extra drive circuits
depends
with: IJ01, IJ02,


of actuator
some configurations,
on the print head
substantially upon
IJ03, IJ04, IJ05,


pulses
this may cause heat
Can be readily
the configuration of
IJ06, IJ07, IJ09,



build-up at the nozzle
controlled and
the ink jet nozzle
IJ10, IJ11, IJ14,



which boils the ink,
initiated by digital

IJ16, IJ20, IJ22,



clearing the nozzle. In
logic

IJ23, IJ24, IJ25,



other situations, it may


IJ27, IJ28, IJ29,



cause sufficient


IJ30, IJ31, IJ32,



vibrations to dislodge


IJ33, IJ34, IJ36,



clogged nozzles.


IJ37, IJ38, IJ39,






IJ40, IJ41, IJ42,






IJ43, IJ44, IJ45


Extra
Where an actuator is
A simple
Not suitable
May be used


power to
not normally driven to
solution where
where there is a
with: IJ03, IJ09,


ink pushing
the limit of its motion,
applicable
hard limit to
IJ16, IJ20, IJ23,


actuator
nozzle clearing may be

actuator movement
IJ24, IJ25, IJ27,



assisted by providing


IJ29, IJ30, IJ31,



an enhanced drive


IJ32, IJ39, IJ40,



signal to the actuator.


IJ41, IJ42, IJ43,






IJ44, IJ45


Acoustic
An ultrasonic wave is
A high nozzle
High
IJ08, IJ13, IJ15,


resonance
applied to the ink
clearing capability
implementation cost
IJ17, IJ18, IJ19,



chamber. This wave is
can be achieved
if system does not
IJ21



of an appropriate
May be
already include an



amplitude and
implemented at very
acoustic actuator



frequency to cause
low cost in systems



sufficient force at the
which already



nozzle to clear
include acoustic



blockages. This is
actuators



easiest to achieve if



the ultrasonic wave is



at a resonant



frequency of the ink



cavity.


Nozzle
A microfabricated
Can clear
Accurate
Silverbrook, EP


clearing
plate is pushed against
severely clogged
mechanical
0771 658 A2 and


plate
the nozzles. The plate
nozzles
alignment is
related patent



has a post for every

required
applications



nozzle. A post moves

Moving parts are



through each nozzle,

required



displacing dried ink.

There is risk of





damage to the





nozzles





Accurate





fabrication is





required


Ink
The pressure of the ink
May be effective
Requires
May be used


pressure
is temporarily
where other
pressure pump or
with all IJ series ink


pulse
increased so that ink
methods cannot be
other pressure
jets



streams from all of the
used
actuator



nozzles. This may be

Expensive



used in conjunction

Wasteful of ink



with actuator



energizing.


Print head
A flexible ‘blade’ is
Effective for
Difficult to use if
Many ink jet


wiper
wiped across the print
planar print head
print head surface is
systems



head surface. The
surfaces
non-planar or very



blade is usually
Low cost
fragile



fabricated from a

Requires



flexible polymer, e.g.

mechanical parts



rubber or synthetic

Blade can wear



elastomer.

out in high volume





print systems


Separate
A separate heater is
Can be effective
Fabrication
Can be used with


ink boiling
provided at the nozzle
where other nozzle
complexity
many IJ series ink


heater
although the normal
clearing methods

jets



drop e-ection
cannot be used



mechanism does not
Can be



require it. The heaters
implemented at no



do not require
additional cost in



individual drive
some ink jet



circuits, as many
configurations



nozzles can be cleared



simultaneously, and no



imaging is required.



















Nozzle plate construction












Description
Advantages
Disadvantages
Examples





Electroformed
A nozzle plate is
Fabrication
High
Hewlett Packard


nickel
separately fabricated
simplicity
temperatures and
Thermal Ink jet



from electroformed

pressures are



nickel, and bonded to

required to bond



the print head chip.

nozzle plate





Minimum





thickness constraints





Differential





thermal expansion


Laser
Individual nozzle
No masks
Each hole must
Canon Bubblejet


ablated or
holes are ablated by an
required
be individually
1988 Sercel et


drilled
intense UV laser in a
Can be quite fast
formed
al., SPIE, Vol. 998


polymer
nozzle plate, which is
Some control
Special
Excimer Beam



typically a polymer
over nozzle profile
equipment required
Applications, pp.



such as polyimide or
is possible
Slow where there
76-83



polysulphone
Equipment
are many thousands
1993 Watanabe




required is relatively
of nozzles per print
et al., U.S. Pat. No.




low cost
head
5,208,604





May produce thin





burrs at exit holes


Silicon
A separate nozzle
High accuracy is
Two part
K. Bean, IEEE


micromachined
plate is
attainable
construction
Transactions on



micromachined from

High cost
Electron Devices,



single crystal silicon,

Requires
Vol. ED-25, No. 10,



and bonded to the

precision alignment
1978, pp 1185-1195



print head wafer.

Nozzles may be
Xerox 1990





clogged by adhesive
Hawkins et al., U.S. Pat. No.






4,899,181


Glass
Fine glass capillaries
No expensive
Very small
1970 Zoltan U.S. Pat. No.


capillaries
are drawn from glass
equipment required
nozzle sizes are
3,683,212



tubing. This method
Simple to make
difficult to form



has been used for
single nozzles
Not suited for



making individual

mass production



nozzles, but is difficult



to use for bulk



manufacturing of print



heads with thousands



of nozzles.


Monolithic,
The nozzle plate is
High accuracy
Requires
Silverbrook, EP


surface
deposited as a layer
(<1 μm)
sacrificial layer
0771 658 A2 and


micromachined
using standard VLSI
Monolithic
under the nozzle
related patent


using VLSI
deposition techniques.
Low cost
plate to form the
applications


lithographic
Nozzles are etched in
Existing
nozzle chamber
IJ01, IJ02, IJ04,


processes
the nozzle plate using
processes can be
Surface may be
IJ11, IJ12, IJ17,



VLSI lithography and
used
fragile to the touch
IJ18, IJ20, IJ22,



etching.


IJ24, IJ27, IJ28,






IJ29, IJ30, IJ31,






IJ32, IJ33, IJ34,






IJ36, IJ37, IJ38,






IJ39, IJ40, IJ41,






IJ42, IJ43, IJ44


Monolithic,
The nozzle plate is a
High accuracy
Requires long
IJ03, IJ05, IJ06,


etched
buried etch stop in the
(<1 μm)
etch times
IJ07, IJ08, IJ09,


through
wafer. Nozzle
Monolithic
Requires a
IJ10, IJ13, IJ14,


substrate
chambers are etched in
Low cost
support wafer
IJ15, IJ16, IJ19,



the front of the wafer,
No differential

IJ21, IJ23, IJ25,



and the wafer is
expansion

IJ26



thinned from the back



side. Nozzles are then



etched in the etch stop



layer.


No nozzle
Various methods have
No nozzles to
Difficult to
Ricoh 1995


plate
been tried to eliminate
become clogged
control drop
Sekiya et al U.S. Pat. No.



the nozzles entirely, to

position accurately
5,412,413



prevent nozzle

Crosstalk
1993 Hadimioglu



clogging. These

problems
et al EUP 550,192



include thermal bubble


1993 Elrod et al



mechanisms and


EUP 572,220



acoustic lens



mechanisms


Trough
Each drop ejector has
Reduced
Drop firing
IJ35



a trough through
manufacturing
direction is sensitive



which a paddle moves.
complexity
to wicking.



There is no nozzle
Monolithic



plate.


Nozzle slit
The elimination of
No nozzles to
Difficult to
1989 Saito et al


instead of
nozzle holes and
become clogged
control drop
U.S. Pat. No. 4,799,068


individual
replacement by a slit

position accurately


nozzles
encompassing many

Crosstalk



actuator positions

problems



reduces nozzle



clogging, but increases



crosstalk due to ink



surface waves



















Drop ejection direction












Description
Advantages
Disadvantages
Examples





Edge
Ink flow is along the
Simple
Nozzles limited
Canon Bubblejet


(‘edge
surface of the chip,
construction
to edge
1979 Endo et al GB


shooter’)
and ink drops are
No silicon
High resolution
patent 2,007,162



ejected from the chip
etching required
is difficult
Xerox heater-in-



edge.
Good heat
Fast color
pit 1990 Hawkins et




sinking via substrate
printing requires
al U.S. Pat. No. 4,899,181




Mechanically
one print head per
Tone-jet




strong
color




Ease of chip




handing


Surface
Ink flow is along the
No bulk silicon
Maximum ink
Hewlett-Packard


(‘roof
surface of the chip,
etching required
flow is severely
TIJ 1982 Vaught et


shooter’)
and ink drops are
Silicon can make
restricted
al U.S. Pat. No. 4,490,728



ejected from the chip
an effective heat

IJ02, IJ11, IJ12,



surface, normal to the
sink

IJ20, IJ22



plane of the chip.
Mechanical




strength


Through
Ink flow is through the
High ink flow
Requires bulk
Silverbrook, EP


chip,
chip, and ink drops are
Suitable for
silicon etching
0771 658 A2 and


forward
ejected from the front
pagewidth print

related patent


(‘up
surface of the chip.
heads

applications


shooter’)

High nozzle

IJ04, IJ17, IJ18,




packing density

IJ24, IJ27-IJ45




therefore low




manufacturing cost


Through
Ink flow is through the
High ink flow
Requires wafer
IJ01, IJ03, IJ05,


chip,
chip, and ink drops are
Suitable for
thinning
IJ06, IJ07, IJ08,


reverse
ejected from the rear
pagewidth print
Requires special
IJ09, IJ10, IJ13,


(‘down
surface of the chip.
heads
handling during
IJ14, IJ15, IJ16,


shooter’)

High nozzle
manufacture
IJ19, IJ21, IJ23,




packing density

IJ25, IJ26




therefore low




manufacturing cost


Through
Ink flow is through the
Suitable for
Pagewidth print
Epson Stylus


actuator
actuator, which is not
piezoelectric print
heads require
Tektronix hot



fabricated as part of
heads
several thousand
melt piezoelectric



the same substrate as

connections to drive
ink jets



the drive transistors.

circuits





Cannot be





manufactured in





standard CMOS





fabs





Complex





assembly required



















Ink type












Description
Advantages
Disadvantages
Examples





Aqueous,
Water based ink which
Environmentally
Slow drying
Most existing ink


dye
typically contains:
friendly
Corrosive
jets



water, dye, surfactant,
No odor
Bleeds on paper
All IJ series ink



humectant, and

May
jets



biocide.

strikethrough
Silverbrook, EP



Modern ink dyes have

Cockles paper
0771 658 A2 and



high water-fastness,


related patent



light fastness


applications


Aqueous,
Water based ink which
Environmentally
Slow drying
IJ02, IJ04, IJ21,


pigment
typically contains:
friendly
Corrosive
IJ26, IJ27, IJ30



water, pigment,
No odor
Pigment may
Silverbrook, EP



surfactant, humectant,
Reduced bleed
clog nozzles
0771 658 A2 and



and biocide.
Reduced wicking
Pigment may
related patent



Pigments have an
Reduced
clog actuator
applications



advantage in reduced
strikethrough
mechanisms
Piezoelectric ink-



bleed, wicking and

Cockles paper
jets



strikethrough.


Thermal ink jets






(with significant






restrictions)


Methyl
MEK is a highly
Very fast drying
Odorous
All IJ series ink


Ethyl
volatile solvent used
Prints on various
Flammable
jets


Ketone
for industrial printing
substrates such as


(MEK)
on difficult surfaces
metals and plastics



such as aluminum



cans.


Alcohol
Alcohol based inks
Fast drying
Slight odor
All IJ series ink


(ethanol, 2-
can be used where the
Operates at sub-
Flammable
jets


butanol,
printer must operate at
freezing


and others)
temperatures below
temperatures



the freezing point of
Reduced paper



water. An example of
cockle



this is in-camera
Low cost



consumer



photographic printing.


Phase
The ink is solid at
No drying time-
High viscosity
Tektronix hot


change
room temperature, and
ink instantly freezes
Printed ink
melt piezoelectric


(hot melt)
is melted in the print
on the print medium
typically has a
ink jets



head before jetting.
Almost any print
‘waxy’ feel
1989 Nowak



Hot melt inks are
medium can be used
Printed pages
U.S. Pat. No. 4,820,346



usually wax based,
No paper cockle
may ‘block’
All IJ series ink



with a melting point
occurs
Ink temperature
jets



around 80° C. After
No wicking
may be above the



jetting the ink freezes
occurs
curie point of



almost instantly upon
No bleed occurs
permanent magnets



contacting the print
No strikethrough
Ink heaters



medium or a transfer
occurs
consume power



roller.

Long warm-up





time


Oil
Oil based inks are
High solubility
High viscosity:
All IJ series ink



extensively used in
medium for some
this is a significant
jets



offset printing. They
dyes
limitation for use in



have advantages in
Does not cockle
ink jets, which



improved
paper
usually require a



characteristics on
Does not wick
low viscosity. Some



paper (especially no
through paper
short chain and



wicking or cockle).

multi-branched oils



Oil soluble dies and

have a sufficiently



pigments are required.

low viscosity.





Slow drying


Microemulsion
A microemulsion is a
Stops ink bleed
Viscosity higher
All IJ series ink



stable, self forming
High dye
than water
jets



emulsion of oil, water,
solubility
Cost is slightly



and surfactant. The
Water, oil, and
higher than water



characteristic drop size
amphiphilic soluble
based ink



is less than 100 nm,
dies can be used
High surfactant



and is determined by
Can stabilize
concentration



the preferred curvature
pigment
required (around



of the surfactant.
suspensions
5%)









While the present invention has been illustrated and described with reference to exemplary embodiments thereof, various modifications will be apparent to and might readily be made by those skilled in the art without departing from the scope and spirit of the present invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description as set forth herein, but, rather, that the claims be broadly construed.

## Claims

1. A printhead assembly with a communications module for a printing system, the printhead assembly comprising:
a casing;
a printhead module;
a plurality of printed circuit boards each mounted to the casing by a support member and electrically connected to the printhead module, the support members having matching engagement portions at which the associated printed circuit boards are electrically connected to each other;
a fluid channel member positioned adjacent to the printhead module, the fluid channel member including a plurality of ducts that substantially span the length of the printhead module; and
a connector arrangement removably mounted to a distal end of the casing, the connector arrangement incorporating:
a power supply connection port electrically connected to at least one busbar that substantially spans the length of the printhead module;
a fluid delivery connection port in fluid communication with the fluid channel member;
an engagement portion which matches the engagement portions of the support members; and,
a data connection port electrically connected to the printed circuit board positioned at the distal end of the casing at the matching engagement portions of the connector arrangement and support member supporting said printed circuit board.

2. The printhead assembly as claimed in claim 1, wherein the printhead module includes a plurality of printhead tiles.

3. The printhead assembly as claimed in claim 2, wherein each printhead tile is in electrical connection with the power supply port, data communication with the data port and fluid communication with the fluid delivery port.

4. The printhead assembly as claimed in claim 1, wherein the fluid channel member is provided with a female end portion at one distal end and a male end portion at the other distal end.

5. The printhead assembly as claimed in claim 4, wherein more than one fluid channel member can be fixedly associated together in an end to end arrangement.

6. The printhead assembly as claimed in claim 1, wherein the fluid channel member includes a series of fluid outlet ports arranged along the length of the fluid channel member.

7. The printhead assembly as claimed in claim 1, wherein the fluid channel member has a female end or a male end to engage the fluid delivery connection port.

8. The printhead assembly as claimed in claim 1, wherein the fluid delivery connection port is provided with tubular portions to attach to a plurality of ink fluid supply tubes.

9. The printhead assembly as claimed in claim 1, wherein each printhead tile is supported by the fluid channel member.

10. The printhead assembly as claimed in claim 1, wherein the connector arrangement includes a spring portion.

11. The printhead assembly as claimed in claim 10, wherein the spring portion is at least one integrated serpentine member of the connector arrangement.

12. The printhead assembly as claimed in claim 1, wherein an endplate is disposed between the casing and the connection ports.

13. The printhead assembly as claimed in claim 1, wherein the printhead module prints a wallpaper pattern on to a media web to produce wallpaper.

14. The printhead assembly as claimed in claim 1, for use in a mobile printer for producing printed media web, the printer comprising:
a vehicle adapted to hold and transport the printer;
input means for a consumer to select a print pattern to be printed on a media web to form the printed media web;
at least one media cartridge containing the media web;
a printhead extending at least the width of the media web;
drive means to drive the media web past the printhead; and,
at least one processor to receive and process the selected print pattern and to control printing of the selected print pattern.