Patent Publication Number: US-2010119286-A1

Title: Printing System Having Selectively Controlled Slitter

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This present application is a Continuation of U.S. application Ser. No. 11/599,312 filed Nov. 15, 2006, which is a Continuation of U.S. application Ser. No. 10/760,221 filed on Jan. 21, 2004, now issued U.S. Pat. No. 7,261,482, all of which are herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a photofinishing system that incorporates a slitting mechanism for printed media and, in one of its possible embodiments, to a digital photofinishing system that provides for page-width printing of print media that is fed directly from a roll of the media to a print head assembly. 
     CROSS-REFERENCE TO CO-PENDING APPLICATIONS 
     The following applications have been filed by the Applicant with the present application: 
     
       
         
           
               
               
               
               
               
             
               
                   
               
             
            
               
                 7,156,508 
                 7,159,972 
                 7,083,271 
                 7,165,834 
                 7,080,894 
               
               
                 7,201,469 
                 7,090,336 
                 7,156,489 
                 7,413,283 
                 7,438,385 
               
               
                 7,083,257 
                 7,258,422 
                 7,255,423 
                 7,219,980 
                 7,591,533 
               
               
                 7,416,274 
                 7,367,649 
                 7,118,192 
                 7,618,121 
                 7,322,672 
               
               
                 7,077,505 
                 7,198,354 
                 7,077,504 
                 7,614,724 
                 7,198,355 
               
               
                 7,401,894 
                 7,322,676 
                 7,152,959 
                 7,213,906 
                 7,178,901 
               
               
                 7,222,938 
                 7,108,353 
                 7,104,629 
                 7,448,734 
                 7,425,050 
               
               
                 7,364,263 
                 7,201,468 
                 7,360,868 
                 7,147,102 
                 7,234,802 
               
               
                 7,303,255 
                 7,287,846 
                 7,156,511 
                 10/760,264 
                 7,258,432 
               
               
                 7,097,291 
                 10/760,222 
                 10/760,248 
                 7,083,273 
                 7,367,647 
               
               
                 7,374,355 
                 7,441,880 
                 7,547,092 
                 10/760,206 
                 7,513,598 
               
               
                 10/760,270 
                 7,198,352 
                 7,364,264 
                 7,303,251 
                 7,201,470 
               
               
                 7,121,655 
                 7,293,861 
                 7,232,208 
                 7,328,985 
                 7,344,232 
               
               
                 7,083,272 
                 7,249,838 
                 7,111,935 
                 7,562,971 
                 10/760,219 
               
               
                 7,604,322 
                 10/760,220 
                 7,002,664 
                 10/760,252 
                 7,287,828 
               
               
                 7,237,888 
                 7,168,654 
                 7,201,272 
                 6,991,098 
                 7,217,051 
               
               
                 6,944,970 
                 10/760,215 
                 7,108,434 
                 7,607,756 
                 7,210,407 
               
               
                 7,186,042 
                 10/760,266 
                 6,920,704 
                 7,217,049 
                 10/760,241 
               
               
                 10/760,260 
               
               
                   
               
            
           
         
       
     
     The disclosures of these co-pending applications are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Digital photofinishing systems are known and employ a variety of technologies, including laser exposure of photographic film, dye sublimation and inkjet printing using conventional types of printers. The present invention has been developed to provide for page-width printing of print media that is fed directly from a roll of the media to a print head assembly and then to slitting of the printed media so as to facilitate application of the invention to photographic processing in the context of so-called Minilab photographic services. 
     SUMMARY OF THE INVENTION 
     Broadly defined, the present invention provides photofinishing system comprising a processor, a printer, means for feeding print media to the printer from a roll of the print media, and slitter means located in series with the printer; the processor being arranged to generate a drive signal that is representative of a photographic image, the printer being coupled to the processor and being arranged to process the drive signal and effect printing of the photographic image on the print media, and the slitter means being arranged to receive printed media following its passage through the printer, to transport the printed media in a direction away from the printer and, in use, to slit the printed media in the longitudinal direction of transportation of the media. 
     The photofinishing system advantageously comprises a digital processor which is arranged to receive digitised data that is representative of a photographic image and to process the data in a manner to generate a printer drive signal that is representative of the photographic image, and the printer is advantageously arranged to process the drive signal and effect page-width printing of the photographic image on the print media as it is fed directly to the printer from the roll. 
     The invention will be more fully understood from the following description of an embodiment of a digital photofinishing system that incorporates an exemplified form of the invention. The description is provided with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  shows a schematic representation of the digital photofinishing system, 
         FIG. 2  shows in perspective cabinetry that mounts and contains components of the digital photofinishing system, 
         FIG. 3  shows cabinetry that is similar to that of  FIG. 2  but which also incorporates a conventional film processing system, 
         FIG. 4  shows an exploded perspective view of the cabinetry of  FIG. 1  and components of the digital photofinishing system, 
         FIGS. 5 and 6  show right hand and left hand perspective views respectively of the components of the digital photofinishing system removed from the cabinetry of  FIG. 1 , 
         FIG. 7  shows an exploded perspective view of the components of  FIGS. 5 and 6  together with ancillary components, 
         FIG. 8  shows a sectional elevation view of the components of  FIGS. 5 and 6 , 
         FIG. 9  shows a perspective view of two (upper and lower) confronting print head assemblies that constitute components of the digital photofinishing system, 
         FIG. 10  shows an exploded perspective view of the print head assemblies of  FIG. 9 , 
         FIG. 11  shows a sectional end view of one print head assembly of a type that is slightly different in construction from that shown in  FIGS. 9 and 10 , 
         FIG. 12  shows a perspective view of an end portion of a channelled support member removed from the print head assembly of  FIG. 11  and fluid delivery lines connected to the support member, 
         FIG. 13  shows an end view of connections made between the fluid delivery lines and the channelled support member of  FIG. 12 , 
         FIG. 14  shows a printed circuit board, with electronic components mounted to the board, when removed from a casing portion of the print head assembly of  FIG. 11 , 
         FIGS. 15 and 16  show right hand and left hand views respectively of a cartridge that constitutes a removable/replaceable component of the digital photofinishing system, 
         FIG. 17  shows an exploded perspective view of the cartridge as shown in  FIGS. 15 and 16 , 
         FIG. 18  shows, in perspective, a sectional view of a portion a print head chip that incorporates printing fluid delivery nozzles and, in the form of an integrated circuit, nozzle actuators, 
         FIG. 19  shows a vertical section of a single nozzle in a quiescent state, 
         FIG. 20  shows a vertical section of a single nozzle in an initial activation state, 
         FIG. 21  shows a vertical section of a single nozzle in a later activation state, 
         FIG. 22  shows a perspective view of a single nozzle in the activation state shown in  FIG. 21 , 
         FIG. 23  shows in perspective a sectioned view of the nozzle of  FIG. 22 , 
         FIG. 24  shows a sectional elevation view of the nozzle of  FIG. 22 , 
         FIG. 25  shows in perspective a partial sectional view of the nozzle of  FIG. 20 , 
         FIG. 26  shows a plan view of the nozzle of  FIG. 19 , 
         FIG. 27  shows a view similar to  FIG. 26  but with lever arm and moveable nozzle portions omitted, 
         FIG. 28  illustrates data flow and functions performed by a print engine controller (“PEC”) that forms one of the circuit components shown in  FIG. 14 , 
         FIG. 29  illustrates the PEC of  FIG. 28  in the context of an overall printing system architecture, and 
         FIG. 30  illustrates the architecture of the PEC of  FIG. 29 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT 
     As illustrated schematically in  FIG. 1 , the digital photofinishing system (referred to hereinafter as a “photofinishing system”) comprises a computer  20  which is arranged selectively to receive an input from an input source  21  which, although not specifically illustrated in  FIG. 1 , might typically comprise one or more of: 
     a) A scanning device.
 
b) A dedicated photo (film or print) scanning device.
 
c) A computer disk.
 
d) A digital camera output.
 
e) A digital camera memory card.
 
f) A digital file stored on a photographic negative or print.
 
g) An internet (or intranet) connection.
 
     A control and/or monitoring device  22  is connected to the computer for effecting control and/or monitoring functions and, although not specifically illustrated, such device might typically comprise one or more of: 
     a) A keyboard.
 
b) A touch screen, as illustrated in  FIGS. 2 and 3 .
 
c) A mouse.
 
d) A monitor.
 
     Digital output signals  23  from the computer might be directed or routed to one or more of a variety of devices such as: 
     a) A data storage device.
 
b) A file storage device or system.
 
c) An internet connection.
 
d) One or more printers  24  as shown inter alia in  FIG. 1 .
 
     A print media supply  25 , a printing fluid supply  26  and an air supply  27  are coupled to the (or each) printer  24 , and printed media from the printer(s)  24  is directed to a storage device  28  by way of a drier  29  and a slitting device  30 . 
     The photofinishing system as illustrated in  FIG. 1  may comprise and be termed a “digital minilab” for processing and printing photographic images that are fed to the computer  20 , either directly or indirectly, as digitised images from input sources such as those referred to previously. In such case the print media supply  25  might comprise paper, card or plastic foil, all in either sheet or roll form, and the printing fluid supply might comprise one or more printing inks, depending upon whether the printer(s) is (or are) driven to produce colour prints, black-on-white prints or “invisible” infrared digital image encoded prints. Also, when processing and printing photographic images, the slitting device  30  may be driven to cut differently sized prints from a single width roll of print media. Thus, assuming a 12 inch (−30 mm) wide roll of print media, the media may, for example, be slit to produce photographic prints having sizes selected from: 
     1-12×8 print
 
1-12×4 print
 
2-6×4 prints
 
3-4×6 prints
 
4-3×5 prints.
 
     An important feature of the photofinishing system is that it employs what might be termed plain paper, page-width printing of photographic images. Thus, unlike conventional types of photographic minilabs that require: the development of film, the use of sensitised (coated) printing papers, specialised chemicals for use in developing, printing, stopping and fixing images, and skilled manipulation of developing/printing processes; the photofinishing system as described herein effectively embodies a computer controlled printing system which, at least in some embodiments, provides for relatively simple, high speed yet flexible digital processing and subsequent page-width printing of photographic images. 
     The photofinishing system may be integrated in the cabinetry shown in  FIGS. 2 and 4  and, in that form, comprise a cabinet  31  having doors  32 ,  33  and  34 . The cabinet is itself provided internally with an upper shelf  35  for receiving components  36  of the processing system, which are referred to later in greater detail, and with lower shelves  37  for receiving replacement and/or expended cartridge components  38  which also are referred to later in further detail. Mounted to an upper deck of the cabinet are input signal-generating devices in the form of a flatbed scanner  39 , a high resolution 35 mm film and/or APS cartridge scanner  40 , a touch screen control/monitoring device  41  incorporating a liquid crystal display, and a USB input and/or output device  42 . 
     Print receiving trays  43  are located at one end of the cabinet and are coupled to a tray elevating device  44  of a conventional form. 
     The photofinishing system may alternatively be integrated in the cabinetry shown in  FIG. 3  and, when in that form, further include a film processing unit  45 . The film processing unit  45 , although not illustrated in detail, comprises film processing apparatus of a conventional form which is known in the so-called minilab art for chemically developing and printing exposed photographic print and/or slide (transparency) film. Also, although again not shown, the film processing unit  45  includes compartments and/or reservoirs as known in the art for receiving chemicals that conventionally are used in developing, stopping and fixing development and printing of film and print paper. 
     The components  36  of the photofinishing system are now described in greater detail by reference to  FIG. 1  and, selectively, to  FIGS. 4 to 25  of the drawings. 
     Inputs to the computer  20  are provided as standardised image compression signals and are processed, typically as JPEG files, using processing procedures that are known in the art. File manipulation, again using procedures that are known in the art, may be provided for in two ways:
         1) Automatically, for example, for effecting artefact adjustments such as red-eye removal, colour density adjustment and histogram equalisation, and   2) Manually, for example, for effecting such image modifications as colour-to-black-and-white translation, sepia finishing, image rotation and image cropping.       

     The illustrated output  23  (which in practice will be constituted by a plurality of output components) from the computer  20  is directed to the printer  24  which, when in the form illustrated in  FIGS. 9 and 10  comprises two confronting print head assemblies  50  and  51 . The print head assemblies are arranged selectively to direct printing ink onto one or the other or both of two faces of a single sheet of print media or, as in the case of the illustrated photofinishing system, onto one or the other or both of two faces of print media from a roll  75  of print media. 
     The print head assemblies  50  and  51  are mounted in space-apart relationship, that is they are separated by a distance sufficient to permit the passage of the print media between the assemblies during a printing activity, and the print head assemblies are mounted upon a support platform  52 . 
     Each of the print head assemblies  50  and  51  may, for example, be in the form of that which is described in the Applicant&#39;s co-pending US patent applications 
                                                    7,156,508   7,159,972   7,083,271   7,165,834   7,080,894   7,201,469       7,090,336   7,156,489   7,413,283   7,438,385   7,083,257   7,258,422       7,255,423   7,219,980   7,591,533   7,416,274   7,367,649   7,118,192       7,618,121   7,322,672   7,077,505   7,198,354   7,077,504   7,614,724       7,198,355   7,401,894   7,322,676   7,152,959   7,213,906   7,178,901       7,222,938   7,108,353   7,104,629                    
which is incorporated herein by reference, but other types of print head assemblies (including thermal or piezo-electric activated bubble jet printers) that are known in the art may alternatively be employed.
 
     In general terms, and as illustrated in  FIGS. 9 to 14  for exemplification purposes, each of the print head assemblies  50  and  51  comprises four print head modules  55 , each of which in turn comprises a unitary arrangement of:
         a) a plastics material support member  56 ,   b) four print head micro-electro-mechanical system (MEMS) integrated circuit chips  57  (referred to herein simply as “print head chips”),   c) a fluid distribution arrangement  58  mounting each of the print head chips  57  to the support member  56 , and   d) a flexible printed circuit connector  59  for connecting electrical power and signals to each of the print head chips  57 .       

     Each of the chips (as described in more detail later) has up to 7680 nozzles formed therein for delivering printing fluid onto the surface of the print media and, possibly, a further 640 nozzles for delivering pressurised air or other gas toward the print media. 
     The four print head modules  55  are removably located in a channel portion  60  of a casing  61  by way of the support member  56  and the casing contains electrical circuitry  62  mounted on four printed circuit boards  63  (one for each print head module  55 ) for controlling delivery of computer regulated power and drive signals by way of flexible PCB connectors  63   a  to the print head chips  57 . As illustrated in  FIGS. 9 and 10 , electrical power and print activating signals are delivered to one end of the two print head assemblies  50  and  51  by way of conductors  64 , and printing ink and air are delivered to the other end of the two print head assemblies by fluid delivery lines  65 . 
     The printed circuit boards  63  are carried by plastics material mouldings  66  which are located within the casing  61  and the mouldings also carry busbars  67  which in turn carry current for powering the print head chips  57  and the electrical circuitry. A cover  68  normally closes the casing  61  and, when closed, the cover acts against a loading element  69  that functions to urge the flexible printed circuit connector  59  against the busbars  67 . 
     The four print head modules  55  may incorporate four conjoined support members  56  or, alternatively, a single support member  56  may be provided to extend along the full length of each print head assembly  50  and  51  and be shared by all four print head modules. That is, a single support member  56  may carry all sixteen print head chips  57 . 
     As shown in  FIGS. 11 and 12 , the support member  56  comprises an extrusion that is formed with seven longitudinally extending closed channels  70 , and the support member is provided in its upper surface with groups  71  of millimetric sized holes. Each group comprises seven separate holes  72  which extend into respective ones of the channels  70  and each group of holes is associated with one of the print head chips  57 . Also, the holes  72  of each group are positioned obliquely across the support member  56  in the longitudinal direction of the support member. 
     A coupling device  73  is provided for coupling fluid into the seven channels  70  from respective ones of the fluid delivery lines  65 . 
     The fluid distribution arrangements  58  are provided for channelling fluid (printing ink and air) from each group  71  of holes to an associated one of the print head chips  57 . Printing fluids from six of the seven channel  70  are delivered to twelve rows of nozzles on each print head chip  57  (ie, one fluid to two rows) and the millimetric-to-micrometric distribution of the fluids is effected by way of the fluid distribution arrangements  58 . For a more detailed description of one arrangement for achieving this process reference may be made to the co-pending US patent application referred to previously. 
     An illustrative embodiment of one print head chip  57  is described in more detail, with reference to  FIGS. 18 to 27 , toward the end of this drawing-related description; as is an illustrative embodiment of a print engine controller for the print head assemblies  50  and  51 . The print engine controller is later described with reference to  FIGS. 28 to 30 . 
     A print media guide  74  is mounted to each of the print head assemblies  50  and  51  and is shaped and arranged to guide the print media past the printing surface, as defined collectively by the print head chips  57 , in a manner to preclude the print media from contacting the nozzles of the print head chips. 
     As indicated previously, the fluids to be delivered to the print head assemblies  50  and  51  will be determined by the functionality of the processing system. However, as illustrated, provision is made for delivering six printing fluids and air to the print head chips  57  by way of the seven channels  70  in the support member  56 . The six printing fluids may comprise: 
     Cyan printing ink
 
Magenta printing ink
 
Yellow printing ink
 
Black printing ink
 
     Infrared ink 
     Fixative. 
     The filtered air will in use be delivered at a pressure slightly above atmospheric from a pressurised source (not shown) that is integrated in the processing system. 
     The print media may, as indicated previously, be provided in various forms. However, as shown in  FIGS. 8 and 17  the print media is conveniently provided in the form of a paper roll  75  from which paper is, on demand, unrolled and transported through the printing, drying and slitting stages under the control of the computer  20 . 
     As illustrated, the paper roll  75  is housed in and provided by way of a replaceable/rechargeable, primary cartridge  76 , and the printing fluids are provided in refillable, secondary cartridges  77  which are removably located within a tubular core  78  of the primary cartridge  76 . Four only of the secondary cartridges  77  are shown in  FIG. 17  of the drawings, for containing the four printing inks referred to above, but it will be understood that further secondary cartridges may be provided in the same way for infrared ink and for fixative if required. 
     Fluid outlet ports  79  are provided in an end cap  80  that is located in an end wall  81  of the primary cartridge  76  to facilitate connection of the fluid delivery lines  65  to respective ones of the secondary cartridges  77 . 
     The primary cartridge  76  comprises a generally cylindrical housing portion  82 , that is shaped and dimensioned to surround a full roll of the paper  75 , and a generally oblong paper delivery portion  83  that extends forwardly from a lower region of the housing portion  82 . Both the housing portion  82  and the paper delivery portion  83  extend between end walls  81  and  84  of the primary cartridge  76 , and the end walls are provided with bearings  85  which carry the tubular core  78 . Low friction roll support bearings  86  are carried by the tubular core  78  for supporting the paper roll  75 , and an end cap  87  having a bayonet fitting is provided for capping the end of the tubular core that is remote from the end cap  80 . 
     The housing portion  82  of the primary cartridge  76  and the end walls  81  and  84  are, as illustrated, configured and interconnected in a manner to facilitate convenient removal and replacement of a spent roll  75  and empty secondary cartridges  77 . To this end, a latching closure  88  is removably fitted to the end of the cartridge through which replacement paper rolls  75  are loaded. 
     A sliding door  89  is provided in a vertical wall portion of the housing portion  82  immediately above the paper delivery portion  83 . The door  89  is normally biased toward a closed position by a spring  90  and the door is opened only when the cartridge is located in an operating position (to be further described) and drive is to be imparted to the paper roll  75 . 
     Located within and extending along the length of the paper delivery portion  83  of the primary cartridge  76  are a gravity loaded or, if required, a spring loaded tensioning roller  91 , a drive roller  92  which is fitted with a coupling  93  and a pinch roller  94 . A slotted gate  95  is located in the forward face of the paper delivery portion  83  through which paper from the roll  75  is in use directed by the drive and pinch rollers. 
     The complete primary cartridge  76  is fitted as a replaceable unit into a compartment  96  of a mounting platform  97  that supports, inter alia, the print head assemblies  50  and  51 , the drier  29  and the slitting device  30 . The cartridge housing portion  82  and the compartment  96  are sized and arranged to provide a neat sliding fit for the cartridge and to preclude significant relative movement of the components. 
     A paper feed drive mechanism  98  is mounted to the compartment  96  and comprises a pivotable carrier  99  that is pivotally mounted to an upper wall portion  100  of the compartment  96  by way of a pivot axis  101 . A first drive motor  102  is also mounted to the compartment  96  and is coupled to the carrier  99  by way of a drive shaft  103 . Drive is imparted to the shaft  103  by way of a worm wheel and pinion drive arrangement  104 , and pivotal drive is imparted to the pivotable carrier  99  by shaft pinions  105  that mesh with racks  106  that are formed integrally with side members  107  of the pivotable carrier. 
     A second drive motor  108  is mounted to the pivotable carrier  99  and is provided for imparting drive to a primary drive roller  109  by way of a drive belt  110 . 
     In operation of the photofinishing system, when the sliding door  89  is opened, the first drive motor  102  is energised to pivot the carrier  99  such that the primary drive roller  109  is moved into driving engagement with the paper roll  75 , and the second drive motor  108  is then energised to cause rotary drive to be imparted to the paper roll  75 . 
     A third drive motor  111 , which couples with the drive roller  92  by way of the coupling  93 , is also energised in synchronism with the first and second drive motors for directing the paper  75  from the cartridge  76  as it is unwound from the roll  75 . Feedback sensors (not shown) are provided as components of electric control circuitry  112  for the motors  102 ,  108  and  111 . 
     The motor control circuitry  112  is mounted to the mounting platform  97  adjacent components of the computer  20 . As illustrated in  FIG. 7 , those components include a power supply  113 , a CPU  114 , a hard disk drive  115  and PCI boards  116 . 
     The print head assemblies  50  and  51  (as previously described) are mounted to the mounting platform  97  immediately ahead of the slotted gate  97  of the cartridge  76  (in the direction of paper feed) and are selectively driven to deliver printing fluid to one or the other or both faces of the paper as it passes between the print head assemblies. Then, having passed between the print head assemblies the paper is guided into and through the drier  29 . 
     The drier  29  comprises a series of guide rollers  120  that extend between side walls of a housing  121 , and upper and lower blowers  122  are provided for directing drying air onto one or the other or both faces of the paper as it passes through the drier. 
     The slitting device  30  comprises guide rollers  123  and guide vanes  124  that extend between side walls  125  of the slitting device for transporting the paper through the slitting device following its passage through the drier  29 . Also, spaced-apart slitting blades  126  are mounted to shafts  127  which are, in turn, mounted to a rotatable turret  128 , and the turret is selectively positionable, relative to a supporting roller  128   a  to effect one or another of a number of possible slitting operations as previously described. 
     A guillotine  129  is also mounted to the slitting device  30  and is selectively actuatable in conjunction with the slitting device to cut the paper  75  at selected intervals. 
     In operation of the above described and illustrated processing system, an input signal that is representative of a digitised photograph or photograph-type image is input to the computer  20  and processed and, if required, manipulated for the purpose of generating an output signal. The output signal is representative of a photographic image to be printed by the printer  24  and is employed to drive the printer  24  by way of the print head control circuitry  62  in the print head assemblies  50  and  51 . As indicated previously, the print head assemblies are driven to provide on demand page-width printing and relevant (typical) printing characteristics are identified as follows: 
     Pagewidth dimension-150 mm to 1250 mm
 
Print head width-160 mm to 1280 mm
 
Number of print head chips per print head-8 to 64
 
Number of nozzles per print head chip-7680
 
Number of nozzles per colour per print head chip-1280
 
Nozzle activation (repetition) rate-20 to 50 kHz
 
Drop size per nozzle-1.5 to 5.0 picolitre
 
Paper feed rate-Up to 2.0 m per sec
 
     One of the print head chips  57  is now described in more detail with reference to  FIGS. 18 to 27 . 
     As indicated above, each print head chip  57  is provided with 7680 printing fluid delivery nozzles  150 . The nozzles are arrayed in twelve rows  151 , each having 640 nozzles, with an inter-nozzle spacing X of 32 microns, and adjacent rows are staggered by a distance equal to one-half of the inter-nozzle spacing so that a nozzle in one row is positioned mid-way between two nozzles in adjacent rows. Also, there is an inter-nozzle spacing Y of 80 microns between adjacent rows of nozzles. 
     Two adjacent rows of the nozzles  150  are fed from a common supply of printing fluid. This, with the staggered arrangement, allows for closer spacing of ink dots during printing than would be possible with a single row of nozzles and also allows for a level of redundancy that accommodates nozzle failure. 
     The print head chips  57  are manufactured using an integrated circuit fabrication technique and, as previously indicated, embody a micro-electromechanical system (MEMS). 
     Each print head chip  57  includes a silicon wafer substrate  152  and a 0.42 micron 1 P4M 12 volt CMOS microprocessing circuit is formed on the wafer. Thus, a silicon dioxide layer  153  is deposited on the substrate  152  as a dielectric layer and aluminium electrode contact layers  154  are deposited on the silicon dioxide layer  153 . Both the substrate  152  and the layer  153  are etched to define an ink channel  155 , and an aluminium diffusion barrier  156  is positioned about the ink channel  155 . 
     A passivation layer  157  of silicon nitride is deposited over the aluminium contact layers  154  and the layer  153 . Portions of the passivation layer  157  that are positioned over the contact layers  154  have openings  158  therein to provide access to the contact layers. 
     Each nozzle  150  includes a nozzle chamber  159  which is defined by a nozzle wall  160 , a nozzle roof  161  and a radially inner nozzle rim  162 . The ink channel  155  is in fluid communication with the chamber  159 . 
     A moveable rim  163 , that includes a movable seal lip  164 , is located at the lower end of the nozzle wall  160 . An encircling wall  165  surrounds the nozzle and provides a stationery seal lip  166  that, when the nozzle  150  is at rest as shown in  FIG. 19 , is adjacent the moveable rim  163 . A fluidic seal  167  is formed due to the surface tension of ink trapped between the stationery seal  166  and the moveable seal lip  164 . This prevents leakage of ink from the chamber whilst providing a low resistance coupling between the encircling wall  165  and a nozzle wall  160 . 
     The nozzle wall  160  forms part of lever arrangement that is mounted to a carrier  168  having a generally U-shaped profile with a base  169  attached to the layer  157 . The lever arrangement also includes a lever arm  170  that extends from the nozzle wall and incorporates a lateral stiffening beam  171 . The lever arm  170  is attached to as pair of passive beams  172  that are formed from titanium nitride and are positioned at each side of the nozzle as best seen in  FIGS. 22 and 25 . The other ends of the passive beams  172  are attached to the carriers  168 . 
     The lever arm  170  is also attached to an actuator beam  173 , which is formed from TiN. This attachment to the actuator beam is made at a point a small but critical distance higher than the attachments to the passive beam  172 . 
     As can best be seen from  FIGS. 22 and 25 , the actuator beam  173  is substantially U-shaped in plan, defining a current path between an electrode  174  and an opposite electrode  175 . Each of the electrodes  174  and  175  is electrically connected to a respective point in the contact layer  154 . The actuator beam  173  is also mechanically secured to an anchor  176 , and the anchor  176  is configured to constrain motion of the actuator beam  173  to the left of  FIGS. 19 to 21  when the nozzle arrangement is activated. 
     The actuator beam  807  is conductive, being composed of TiN, but has a sufficiently high enough electrical resistance to generate self-heating when a current is passed between the electrodes  174  and  175 . No current flows through the passive beams  172 , so they do experience thermal expansion. 
     In operation, the nozzle is filled with ink  177  that defines a meniscus  178  under the influence of surface tension. The ink is retained in the chamber  159  by the meniscus, and will not generally leak out in the absence of some other physical influence. 
     To fire ink from the nozzle, a current is passed between the contacts  174  and  175 , passing through the actuator beam  173 . The self-heating of the beam  173  causes the beam to expand, and the actuator beam  173  is dimensioned and shaped so that the beam expands predominantly in a horizontal direction with respect to  FIGS. 19 to 21 . The expansion is constrained to the left by the anchor  176 , so the end of the actuator beam  173  adjacent the lever arm  170  is impelled to the right. 
     The relative horizontal inflexibility of the passive beams  172  prevents them from allowing much horizontal movement of the lever arm  170 . 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, in turn, causes the lever arm  170  to move generally downwardly with a pivoting or hinging motion. However, the absence of a true pivot point means that rotation is about a pivot region defined by bending of the passive beams  172 . 
     The downward movement (and slight rotation) of the lever arm  170  is amplified by the distance of the nozzle wall  160  from the passive beams  172 . The downward movement of the nozzle walls and roof causes a pressure increase within the chamber  159 , causing the meniscus  178  to bulge as shown in  FIG. 20 , although the surface tension of the ink causes the fluid seal  11  to be stretched by this motion without allowing ink to leak out. 
     As shown in  FIG. 21 , at the appropriate time the drive current is stopped and the actuator beam  173  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  159 . 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  159  causes thinning, and ultimately snapping, of the bulging meniscus  178  to define an ink drop  179  that continues upwards until it contacts passing print media  75 . 
     Immediately after the drop  179  detaches, the meniscus  178  forms the concave shape shown in  FIG. 21 . Surface tension causes the pressure in the chamber  159  to remain relatively low until ink has been sucked upwards through the inlet  155 , which returns the nozzle arrangement and the ink to the quiescent situation shown in  FIG. 19 . 
     As can best be seen from  FIG. 22 , the print head chip  57  also incorporates a test mechanism that can be used both post-manufacture and periodically after the print head assembly has been installed. The test mechanism includes a pair of contacts  180  that are connected to test circuitry (not shown). A bridging contact  181  is provided on a finger  182  that extends from the lever arm  170 . Because the bridging contact  181  is on the opposite side of the passive beams  172 , actuation of the nozzle causes the bridging contact  181  to move upwardly, into contact with the contacts  180 . Test circuitry can be used to confirm that actuation causes this closing of the circuit formed by the contacts  180  and  181 . If the circuit is closed appropriately, it can generally be assumed that the nozzle is operative. 
     As stated previously the integrated circuits of the print head chips  57  are controlled by the print engine controller (PEC) integrated circuits of the drive electronics  62 . One or more PEC integrated circuits  100  is or are provided (depending upon the printing speed required) in order to enable page-width printing over a variety of different sized pages or continuous sheets. As described previously, each of the printed circuit boards  63  carried by the support moulding  66  carries one PEC integrated circuit  190  ( FIG. 25 ) which interfaces with four of the print head chips  57 , and the PEC integrated circuit  190  essentially drives the integrated circuits of the print head chips  57  and transfers received print data thereto in a form suitable to effect printing. 
     An example of a PEC integrated circuit which is suitable for driving the print head chips is described in the Applicant&#39;s co-pending US patent applications 
                                                6,795,215   7,154,638   6,859,289   6,977,751   6,398,332       6,622,923                    
which are incorporated herein by reference. However, a brief description of the circuit is provided as follows with reference to  FIGS. 28 to 30 .
 
     The data flow and functions performed by the PEC integrated circuit  190  are described for a situation where the PEC integrated circuit is provided for driving a print head assembly  50  an  51  having a plurality of print head modules  55 , that is four modules as described above. As also described above, each print head module  55  provides for six channels of fluid for printing, these being:
         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 indicated in  FIG. 28 , photographic images are supplied to the PEC integrated circuit  190  by the computer  20 , which is programmed to perform the various processing steps  191  to  194  involved in printing an image prior to transmission to the PEC integrated circuit  190 . These steps will typically involve receiving the image data (step  191 ) and storing this data in a memory buffer of the computer system (step  192 ) in which photograph layouts may be produced and any required objects may be added. Pages from the memory buffer are rasterized (step  193 ) and are then compressed (step  194 ) prior to transmission to the PEC integrated circuit  190 . Upon receiving the image data, the PEC integrated circuit  190  processes the data so as to drive the integrated circuits of the print head chips  57 . 
     Due to the page-width nature of the printhead assembly of the present invention, each photographic image should be printed at a constant speed to avoid creating visible artifacts. This means that the printing speed should 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, an image 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. 
     Because contone colour images are reproduced by stochastic dithering, but black text and line graphics are reproduced directly using dots, the compressed 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. If required, a final layer of tags (in IR or black ink) is optionally added to the image for printout. 
     Dither matrix selection regions in the image description are rasterized to a contone-resolution bi-lev bitmap which is losslessly compressed to negligible size and which forms part of the compressed image. The IR layer of the printed page optionally contains encoded tags at a programmable density. 
     Each compressed image is transferred to the PEC integrated circuit  190  where it is then stored in a memory buffer  195 . The compressed image is then retrieved and fed to an image expander  196  in which images are retrieved. If required, any dither may be applied to any contone layer by a dithering means  197  and any black bi-level layer may be composited over the contone layer by a compositor  198  together with any infrared tags which may be rendered by the rendering means  199 . The PEC integrated circuit  190  then drives the integrated circuits of the print head chips  57  to print the composite image data at step  200  to produce a printed (photograph) image  201 . 
     The process performed by the PEC integrated circuit  190  may be considered to consist of a number of distinct stages. The first stage has the ability to expand a JPEG-compressed contone CMYK layer. In parallel with this, bi-level IR tag data can be encoded from the compressed image. The second stage dithers the contone CMYK layer using a dither matrix selected by a dither matrix select map and, if required, composites a bi-level black layer over the resulting bi-level K layer and adds the IR layer to the image. 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 print head assembly  50  and/or  51 . 
       FIG. 29  shows the PEC integrated circuit  190  in the context of the overall printing system architecture. The various components of the architecture include:
         The PEC integrated circuit  190  which is responsible for receiving the compressed page images for storage in a memory buffer  202 , performing the page expansion, black layer compositing and sending the dot data to the print head chips  57 . The PEC integrated circuit  190  may also communicate with a master Quality Assurance (QA) integrated circuit  203  and with an ink cartridge Quality Assurance (QA) integrated circuit  204 . The PEC integrated circuit  190  also provides a means of retrieving the print head assembly characteristics to ensure optimum printing.   The memory buffer  202  for storing the compressed 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.   The master integrated circuit  203  which is matched to the ink cartridge QA integrated circuit  204 . The construction and working of QA integrated circuits is also known to those skilled in the art and a range of known QA processes might be utilized.       
     The PEC integrated circuit  190  of the present invention effectively 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 an image from a compressed form. The print engine functionality includes expanding the image, dithering the contone layer, compositing the black layer over the contone layer,   optionally adding infrared tags, and sending the resultant image to the integrated circuits of the print head chips.   Acting as a print controller for controlling the print head chips  57  and the stepper motors  102 ,  108  and  111  of the printing system.   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. 30 , which provides a more specific, exemplary illustration of the PEC integrated circuit architecture. 
     The PEC integrated circuit  190  incorporates a simple micro-controller CPU core  204  to perform the following functions:
         Perform QA integrated circuit authentication protocols via a serial interface  205  between print images.   Run the stepper motors  102 ,  108  and  111  of the printing system via a parallel interface  206  during printing to control delivery of the paper  75  to the printer for printing.   Synchronize the various components of the PEC integrated circuit  190  during printing.   Provide a means of interfacing with external data requests (programming registers, etc).   Provide a means of interfacing with the print head assemblies&#39; low-speed data requests (such as reading characterization vectors and writing pulse profiles).   Provide a means of writing portrait and landscape tag structures to an external DRAM  207 .       

     In order to perform the image expansion and printing process, the PEC integrated circuit  190  includes a high-speed serial interface  208  (such as a standard IEEE 1394 interface), a standard JPEG decoder  209 , a standard Group 4 Fax decoder  210 , a custom halftoner/compositor (HC)  211 , a custom tag encoder  212 , a line loader/formatter (LLF)  213 , and a print head interface  214  (PHI) which communicates with the print head chips  57 . The decoders  209  and  210  and the tag encoder  212  are buffered to the HC  211 . The tag encoder  212  allocates infrared tags to images. 
     The print engine function works in a double-buffered manner. That is, one image is loaded into the external DRAM  207  via a DRAM interface  215  and a data bus  216  from the high-speed serial interface  208 , while the previously loaded image is read from the DRAM  207  and passed through the print engine process. When the image has been printed, the image just loaded becomes the image being printed, and a new image is loaded via the high-speed serial interface  208 . 
     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 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 print head assembly and ideally it is adjusted to compensate for dead nozzles in the print head assemblies. Up to six channels of bi-level data are produced from this stage. 
     However, it will be understood that not all of the six channels need be activated. For example, the print head modules  55  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 employed. The resultant bi-level CMYK-IR dot-data is buffered and formatted for printing with the integrated circuits of the print head chips  57  via a set of line buffers (not shown). The majority of these line buffers might be ideally stored on the external DRAM  207 . In the final stage, the six channels of bi-level dot data are printed via the PHI  214 . 
     The HC  211  combines the functions of half-toning the contone (typically CMYK) layer to a bi-level version of the same, and compositing the spot  1  bi-level layer over the appropriate half-toned contone layer(s). If there is no K ink, the HC  211  functions 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  211  is an expanded contone layer (from the JPEG decoder  205 ) through a buffer  217 , an expanded bi-level spot1 layer through a buffer  218 , an expanded dither-matrix-select bitmap at typically the same resolution as the contone layer through a buffer  219 , and tag data at full dot resolution through a buffer (FIFO)  220 . 
     The HC  211  uses up to two dither matrices, read from the external DRAM  207 . The output from the HC  211  to the LLF  213  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  211  proceeds until it detects an “end-of-image” condition, or until it is explicitly stopped via a control register (not shown). 
     The LLF  213  receives dot information from the HC  211 , loads the dots for a given print line into appropriate buffer storage (some on integrated circuit (not shown) and some in the external DRAM  207 ) and formats them into the order required for the integrated circuits of the print head chips  57 . More specifically, the input to the LLF  213  is a set of six 32-bit words and a Data Valid bit, all generated by the HC  211 . 
     As previously described, the physical location of the nozzles  150  on the print head chips is in two offset rows  151 , which means that odd and even dots of the same colour are for two different lines. 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  211 , 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 print head assembly. A single PEC integrated circuit  190  may be employed to generate dots for up to 16 print head chips  57  and, in such case, a single odd or even buffer line is therefore 16 sets of 640 dots, for a total of 10,240 bits (1280 bytes). 
     The PHI  214  is the means by which the PEC integrated circuit  190  loads the print head chips  57  with the dots to be printed, and controls the actual dot printing process. It takes input from the LLF  213  and outputs data to the print head chips  57 . The PHI  214  is capable of dealing with a variety of print head assembly lengths and formats. 
     A combined characterization vector of each print head assembly  50  and  51  can be read back via the serial interface  205 . The characterization vector may include dead nozzle information as well as relative printhead module alignment data. Each printhead module can be queried via a low-speed serial bus  221  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  190  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. 
     It will be understood that the broad constructional and operating principles of the photofinishing system of the present invention may be realised with various embodiments. Thus, variations and modifications may be made in respect of the embodiments as specifically described above by way of example.