Abstract:
A print cartridge receptacle assembly including a first modular print cartridge receptacle for removably receiving and supporting a single first print cartridge, a second modular print cartridge receptacle for removably receiving and supporting a single second print cartridge, a separate locking mechanism on the first and second modular print cartridge receptacles for individually locking the first and second print cartridges in the modular print receptacles, and alignment surfaces on the first and second modular print cartridge receptacles for aligning and interlocking the first modular print cartridge with the second modular print cartridge. First and second print cartridge driver circuits are mounted on the first and second modular print cartridge receptacles and electrically connected with first and second electrical interconnects. The print cartridge receptacle assembly is usable in a printing system in conjunction with a mechanism for traversing the modular print cartridge receptacle assembly over a print zone and a media moving mechanism for passing media through the print zone. The invention provides for a modular printing system which allows for flexibility in the design of printers for particular or unique applications. The invention allows for modular print cartridge receptacles to be assembled together to quickly produce a functional specialized printing system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to U.S. patent application Ser. No.09/167,392 filed concurrently herewith, entitled “Modular Print Cartridge Receptacle for Use in Inkjet Printing Systems” which is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to inkjet printers and, more particularly, to an inkjet printing system which uses modular print cartridge receptacles. 
     BACKGROUND OF THE INVENTION 
     Thermal inkjet hardcopy devices such as printers, graphics plotters, facsimile machines and copiers have gained wide acceptance. These hardcopy devices are described by W. J. Lloyd and H. T. Taub in “Ink Jet Devices,” Chapter 13 of  Output Hardcopy Devices  (Ed. R. C. Durbeck and S. Sherr, San Diego: Academic Press, 1988) and U.S. Pat. Nos. 4,490,728 and 4,313,684. The basics of this technology are further disclosed in various articles in several editions of the  Hewlett-Packard Journal  [Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No. 1 (February 1994)], incorporated herein by reference. Inkjet hardcopy devices produce high quality print, are compact and portable, and print quickly and quietly because only ink strikes the paper. 
     An inkjet printer forms a printed image by printing a pattern of individual dots at particular locations of an array defined for the printing medium. The locations are conveniently visualized as being small dots in a rectilinear array. The locations are sometimes “dot locations”, “dot positions”, or pixels”. Thus, the printing operation can be viewed as the filling of a pattern of dot locations with dots of ink. 
     Inkjet hardcopy devices print dots by ejecting very small drops of ink onto the print medium and typically include a movable carriage that supports one or more printheads each having ink ejecting nozzles. The carriage traverses over the surface of the print medium, and the nozzles are controlled to eject drops of ink at appropriate times pursuant to command of a microcomputer or other controller, wherein the timing of the application of the ink drops is intended to correspond to the pattern of pixels of the image being printed. 
     The typical inkjet printhead (i.e., the silicon substrate, structures built on the substrate, and connections to the substrate) uses liquid ink (i.e., dissolved colorants or pigments dispersed in a solvent). It has an array of precisely formed orifices or nozzles attached to a printhead substrate that incorporates an array of ink ejection chambers which receive liquid ink from the ink reservoir. Each chamber is located opposite the nozzle so ink can collect between it and the nozzle. The ejection of ink droplets is typically under the control of a microprocessor, the signals of which are conveyed by electrical traces to the resistor elements. Properly sequencing the operation of each nozzle causes either to eject ink or to refrain from ejecting ink according to the output of the controlling microprocessor to cause characters or images to be printed upon the paper as the printhead moves past the paper or the paper moves past the printhead. 
     Color inkjet hardcopy devices commonly employ a plurality of print cartridges, usually two to four, mounted in the printer carriage to produce a full spectrum of colors. In a printer with four cartridges, each print cartridge can contain a different color ink, with the commonly used base colors being cyan, magenta, yellow, and black. In a printer with two cartridges, one cartridge can contain black ink with the other cartridge being a tri-compartment cartridge containing the base color cyan, magenta and yellow inks, or alternatively, two dual-compartment cartridges may be used to contain the four color inks. In addition, two tri-compartment cartridges may be used to contain six base color inks, for example, black, cyan, magenta, yellow, light cyan and light magenta. Further, other combinations can be employed depending on the number of different base color inks to be used. 
     The base colors are produced on the media by depositing a drop of the required color onto a dot location, while secondary or shaded colors are formed by depositing multiple drops of different base color inks onto the same dot location, with the overprinting of two or more base colors producing the secondary colors according to well established optical principles. 
     For many applications, such as personal computer printers and fax machines, the ink reservoir has been incorporated into the pen body such that when the pen runs out of ink, the entire pen, including the printhead, is replaced. 
     However, for other hardcopy high volume printing applications, such as large format plotting of engineering drawings, color posters and the like, there is a requirement for the use of much larger volumes of ink than can be contained within the replaceable pens. Therefore, various off-board ink reservoir systems have been developed recently which provide an external stationary ink supply connected to the scanning cartridge via a tube. The external ink supply is typically known as an “off-axis,” “off-board,” or “off-carriage” ink supply. 
     There is a trend to use inkjet printing in new specialized printing systems which are very different systems compared to desk-top printers and facsimile machines, or from large format plotters. These specialized printing systems include applications, such as postal printing, postal franking and bar code printing. Currently, there is no means to design a specialized printing system without a substantial engineering effort. 
     The disadvantages of prior solutions to specialized printing requirements is that the mechanical fixturing and electronics of current print cartridge receptacles are not flexible or modular enough to be used in applications that are not a continuation of the same product concept. For example, the carriage and electronics for a printer or facsimile machine cannot be easily leveraged to an application where specialized printing such as high volume postal franking or bar coding is required. Accordingly, with prior solutions there is no means to design a specialized printing system without a substantial engineering effort. 
     Accordingly, there is a need for a solution to the varied needs of specialty printing systems that provides flexibility and ease of adaptability, accurate and inexpensive methods of alignment of print cartridges and modular electrical connections between the print cartridge and the printer. 
     SUMMARY OF THE INVENTION 
     The present invention provides a print cartridge receptacle assembly including a first modular print cartridge receptacle for removably receiving and supporting a single first print cartridge, a second modular print cartridge receptacle for removably receiving and supporting a single second print cartridge, a separate locking mechanism on the first and second modular print cartridge receptacles for individually locking the first and second print cartridges in the modular print cartridge receptacles and alignment surfaces on the first and second modular print cartridge receptacles for aligning and interlocking the first modular print cartridge receptacle with the second modular print cartridge receptacle. Another embodiment provides a print cartridge receptacle assembly including a first modular print cartridge receptacle for removably receiving and supporting a single first print cartridge, a second modular print cartridge receptacle for removably receiving and supporting a single second print cartridge, a separate locking mechanism on the first and second modular print cartridge receptacles for individually locking the first and second print cartridges in the modular print cartridge receptacles and first and second print cartridge driver circuits mounted on the first and second modular print cartridge receptacles and electrically connected with a first and second electrical interconnect on the first and second modular print cartridge receptacles for receiving signals from the first and second electrical interconnects. The present invention also provides for a printing system using the above embodiments in conjunction with providing a mechanism for traversing the modular print cartridge receptacle assembly over a print zone and a media moving mechanism for passing media through the print zone. 
     The present invention provides for a modular printing system which allows for flexibility in the design of printers for particular or unique applications. The invention allows for multiple modular print cartridge receptacles to be assembled together to quickly produce a functional specialized printing system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A comprising FIGS. 1A,  1 B and  1 C, are perspective views of a first inkjet print cartridge which can be used with the present invention as seen from the bottom rear, top rear and bottom front, respectively. 
     FIG. 2 is a perspective view of a second inkjet print cartridge which can be used with the present invention. 
     FIG. 3 is a perspective front right view of a singular modular print cartridge receptacle of the present invention. 
     FIG. 4 is a perspective back right view of a singular modular print cartridge receptacle of the present invention. 
     FIG. 5 is a perspective front left view of a singular modular print cartridge receptacle of the present invention. 
     FIGS. 6 a - 6   b  are a view of the front and back walls of the modular print cartridge receptacle removed from the modular print cartridge receptacle. 
     FIG. 7 is a perspective view of four modular print cartridge receptacles assembled in an aligned arrangement into a modular print cartridge receptacle assembly and showing one print cartridge installed in the modular assembly. 
     FIG. 8 is a perspective view of four modular print cartridge receptacles assembled in a staggered arrangement into a modular print cartridge receptacle assembly. 
     FIGS. 9 a - 9   c  is a plan view of some different possible assembled configurations of modular print cartridge receptacles  30  and associated print cartridges as viewed upward from below the print cartridges to show the nozzle array  16 . 
     FIG. 10 is a simplified schematic perspective view of an inkjet printer which incorporates four modular print cartridge receptacles, with print cartridges installed, assembled into a modular print cartridge receptacle assembly. 
     FIG. 11 is a simplified schematic perspective view of an inkjet printer which incorporates four modular print cartridge receptacles, without print cartridges installed, assembled into a modular print cartridge receptacle assembly. 
     FIG. 12 is a perspective view of an inkjet printer with a scanning carriage which incorporates the modular print cartridge receptacle of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1A,  1 B and  1 C, shown is an inkjet print cartridge  10  which maybe used in the present invention. The inkjet print cartridge  10  includes two side walls  12  and a perimeter wall  13  and a printhead  14  affixed to the “snout” portion  15  of the perimeter wall  13 . The printhead  14  includes a nozzle member  16  comprising two parallel columns of offset holes or orifices  17  formed in a flexible polymer flexible circuit  18  by, for example, laser ablation. 
     The flexible circuit  18  is bent over the back edge of the print cartridge “snout” and extends down the back perimeter wall of the snout. This flap portion of the flexible circuit  18  is needed for the routing of conductive traces  19  which are connected to substrate electrodes (not shown). The contact pads  20  are located on the flexible circuit  18  which is secured to the back of perimeter wall  13  and the conductive traces  19  are routed over the bend and are connected to the substrate electrodes. 
     Printhead  14  has affixed to the back of the flexible circuit  18  the silicon substrate containing a plurality of individually energizable thin film resistors. Each resistor is located generally behind a single orifice  17  and acts as a heater resistor for ejecting ink droplets when selectively energized by one or more pulses applied sequentially or simultaneously to one or more of the contact pads  20 . 
     Windows  22  extend through the flexible circuit  18  and are used to facilitate bonding of the conductive traces  19  to the electrodes on the silicon substrate. The windows  22  are filled with an encapsulant after bonding the conductive traces  19  to the electrodes on the silicon substrate to protect any underlying portion of the traces and substrate. 
     The back surface of the flexible circuit  18  includes conductive traces  19  formed thereon using a conventional photolithographic etching and/or plating process. These conductive traces are terminated by contact pads  20  designed to interconnect with a modular print cartridge receptacle described below. The print cartridge  10  is designed to so that the contact pads  20 , on the front surface of the flexible circuit  18 , contact electrodes when the print cartridge is installed in a modular print cartridge receptacle. 
     The print cartridge  10  also includes datums for accurately aligning the print cartridge and the nozzle member  16  in the modular print cartridge receptacle of the present invention discussed below. The print cartridge  10  is provided with three datum surfaces  26  located on the perimeter of a sidewall of print cartridge  10  and sufficiently spaced apart from each other to provide accurate and stable alignment. The print cartridge is also provided with a forwardly facing fourth datum surface  25  located on the front lower portion of the snout and with a downwardly facing fifth datum surface  27  on the perimeter wall of the print cartridge adjacent the fourth datum surface, so as to establish a pivot axis above and in front of the snout, and with a rearwardly facing sixth datum surface  24  on the upper end of the print cartridge perimeter wall  13 , the fifth datum surface  25  is used to determine the spacing of the nozzle to the print medium and the sixth datum surface is used to determine angular orientation of the print cartridge about a pivot point. 
     Alignment between two or more nozzle plates affixed to print cartridges installed in a modular print cartridge receptacle is achieved by machining datum projections  24 - 27  on each print cartridge after its nozzle plate  16  has been permanently secured to the print cartridge. The machined datum projections  24 - 27  on the print cartridge contact mating surfaces on a modular print cartridge receptacle described below when print cartridge  10  is installed in the modular print cartridge receptacle. The datums affect the position of the cartridge  10 , and hence the nozzle plate  16 , within the modular print cartridge receptacle. Print cartridge  10  also has a latch engaging portion  28  having an angled surface  29  between the horizontal and vertical directions for engaging with a latching mechanism on the modular print cartridge receptacle to be described below. 
     For further details regarding the datums see U.S. Pat. No. 5,646,665 entitled “Side Biased Datum Scheme for Inkjet Cartridge and Carriage;” U.S. Pat. No. 4,907,018 entitled “Printhead-carriage Alignment and Electrical Interconnect Lock-inmechanism” U.S. Pat. No. 5,617,128 entitled “Alignment of Multiple Nozzle Members in a Printer;” and U.S. Pat. No. 5,408,746 entitled “Datum Formation for Improved Alignment of Multiple Nozzle Members in a Printer” which are herein incorporated by reference. 
     While print cartridge  10  is shown in FIG. 1 has an integral ink supply, print cartridge  10  is readily modified to receive ink from an off-axis ink supply. See, U.S. Pat. No. 5,675,367 entitled “Inkjet Print Cartridge Having Handle Which Incorporates an Ink Fill Port;” Wu, et al., U.S. patent application Ser. No. 09/045,151, filed Mar. 19, 1998, entitled “Alignment Coupling Device for Manually Connecting an Ink Supply to an Inkjet Print Cartridge” and Wu, et al., U.S. patent application Ser. No. 09/045,150, filed Mar. 19, 1998, entitled “Ink Replenishment System with an Open-valve Printhead Fill Port Continuously Connected to an Ink Supply” which are herein incorporated by reference. 
     FIG. 2 is a perspective view of another print cartridge  11  using an off-axis ink supply. A shroud  29  surrounds an inlet needle and helps align a septum (not shown) on the printer with the print cartridge inlet needle when installing modular print cartridge receptacle  30  in a printer. The septum is in fluidic communication with an off-axis ink supply  30 . Accordingly, when the inlet needle is inserted into the septum, print cartridge  11  is in fluid communication with an off-axis ink supply. A regulator valve (not shown) within print cartridge  11  regulates pressure by opening and closing an inlet hole to an internal ink reservoir  12  of print cartridge  11 . For a description of the design and operation of the regulator see U.S. patent application Ser. No. 08/706121, filed Aug. 30, 1996, entitled “Inkjet Printing System with Off-Axis Ink Supply Having Ink Path Which Does Not Extend above Print Cartridge,” which is herein incorporated by reference. The other functional aspects of print cartridge  11  are the same as described for print cartridge  10  above. 
     A demultiplexer (not shown) may be formed on the substrate for demultiplexing the incoming multiplexed signals and distributing the address and primitive signals to the heater resistors. The demultiplexer demultiplexes the incoming electrical signals into signals to be applied to the heater resistors to selectively energize the various heater resistors to eject droplets of ink from nozzles  17  on a receiving media in the print zone. The demultiplexer enables the use of fewer contact pads  20  than heater resistors. Further details regarding multiplexing are provided in U.S. Pat. No. 5,541,269, issued Jul. 30, 1996, entitled “Printhead with Reduced Interconnections to a Printer,” which is herein incorporated by reference. 
     Preferably, an integrated circuit logic using CMOS technology can be placed on the substrate in place of the demultiplexer in order to decode more complex incoming data signals than just multiplexed address signals and primitive signals, thus further reducing the number of contact pads  20  required. The incoming data signals are decoded by the integrated logic circuits on the printhead into address line and primitive firing signals. Performing this operation in the integrated logic circuits on the printhead increases the signal processing speed and the firing frequency of the printhead. 
     While the following discussion and figures relate to the print cartridge shown in FIG. 1, one will readily recognize that the following discussion is equally applicable to the print cartridge of FIG.  2 . FIGS. 3,  4  and  5  are perspective front and rear views of the single modular print cartridge receptacle  30  of the present invention. 
     The modular print cartridge receptacle  30  includes a right sidewall  34 , a left sidewall  36  and a back wall  38  rigidly attached to sidewalls  34 ,  36 . Back wall  38  contains the electrical connections, or electrodes  32 , a print cartridge driver circuit, or print ASIC  48 , and electrical pin connectors  49  for electrical connection to a printer controller. Additional details of the front and back, or outside and inside of back wall  38  is described below in reference to FIG.  6 . The modular print cartridge receptacle  30  also includes a partial bottom  39  attached to a portion of right sidewall  34  and left sidewall  36  to maintain rigidity of sidewalls  34 ,  36  and a datum reference surface. The bottom has an opening for snout  15  of print cartridge  10  and has a datum mating surface for engaging datum  27  on print cartridge  10  when print cartridge  10  is installed in the modular receptacle  30 , thereby providing precise printhead to print media spacing. Optionally, modular receptacle  30  may also have a front wall  42  for providing further rigidity of the modular receptacle. 
     Referring to FIG.  6 ( b ), back wall  38  has electrodes  32  mounted on the inside wall of back wall  38 . The modular print cartridge receptacle  30  is designed so that when print cartridge  10  is installed in modular print cartridge receptacle  30 , the contact pads  20 , on the flexible circuit  18  of the print cartridge, align with and make contact with electrodes  32  on modular print cartridge receptacle  30  when the print cartridge  10  is installed in the modular print cartridge receptacle. The electrodes provide externally generated energization signals to the print cartridge  10 . Preferably, the electrodes  32  on modular print cartridge receptacle  30  are resiliently biased toward the contact pads  20  on print cartridge  10  to ensure a reliable contact. Such electrodes are found in U.S. Pat. Nos. 5,608,434, 5,461,482, 5,372,512 and 5,684,518 all assigned to the present assignee and incorporated herein by reference. 
     As shown in FIG.  6 ( b ), the modular print cartridge receptacle  30 , also contains a print ASIC, or integrated circuit, dedicated to and mounted on the modular print cartridge receptacle. While the print ASIC may be mounted anywhere on the modular print cartridge receptacle, preferably, the print ASIC is mounted on the back wall  38  ease of electrical connection. The print ASIC interprets signals from a printer controller and delivers control signals to the electrodes  32  which in turn provide control signals to the print cartridge  10 . As shown in FIG.  6 ( a ), the modular print cartridge receptacle  30  also contains electrical connectors  49  for connection to a printer preferably, the electrical connectors  49  are mounted on the back wall  38  for ease of electrical connection. 
     When using a printhead with a large number of nozzles and high resolution, correct alignment of all the nozzles so that the ink is correctly placed on the print media is extremely important. Dot alignment must be done in both the horizontal and vertical axes. This requires the nozzle plates on all the print cartridges be aligned precisely with respect to one another after being installed in the modular receptacle and after the modular receptacles are assembled together. In a preferred alignment method, alignment between two or more nozzle plates affixed to print cartridges installed in modular print cartridge receptacle  30  is achieved by machining the datum projections  24 - 27  on each print cartridge  10  after its nozzle plate has been permanently secured to the print cartridge. The machined datum projections on the print cartridge contact surfaces on the modular print cartridge receptacle when the print cartridge is installed in the modular print cartridge receptacle such that the dimensions of the datums affect the position of the cartridge, and hence the nozzle plate, within the modular print cartridge receptacle. 
     Modular print cartridge receptacle  30  has one or more leaf springs  44  attached to right sidewall  34  of modular print cartridge receptacle  30 . The cantilevered leaf springs  44  provide a sideways force. The leaf spring  44  in its uncompressed condition does not lie flat against sidewall  34 , but extends into the interior of modular print cartridge receptacle  30 . Accordingly, leaf springs  44  provide a sideways right to left bias force on the print cartridge  10  toward datum mating surfaces on the interior of left sidewall  36  that align with and engage the three datum surfaces  26  on the print cartridge  10 . 
     The print cartridge can be secured within the modular print cartridge receptacle  30  by a locking mechanism, such as a hinged latch  46  which pivots about axis  47 . When lowered latch  46  presses down on the latch engaging portion  28  of print cartridge  10 . The latch engaging portion  28  on print cartridge  10  has an angled surface  29  between the horizontal and vertical directions for engaging with latch mechanism  46  on the modular print cartridge receptacle  30 . Angled surface  29  causes print cartridge  10  to be biased both downward and leftward so as to engage datums  26  with the mating surfaces on left sidewall  36  of modular receptacle  30 . Alternatively, the locking mechanism may comprise a spring assembly which movably allows the print cartridge to be snapped into the modular print cartridge receptacle  30 . For further details regarding other locking mechanisms see U.S. Pat. No. 5,646,665 entitled “Side Biased Datum Scheme for Inkjet Cartridge and Carriage.” 
     The exterior of right sidewall  34  of modular receptacle  30  contains alignment projections  50 ,  52  and  54  and left sidewall  36  of modular receptacle  30  contains alignment openings  60 ,  62  and  64 . Alignment projections  50 ,  52  and  54  and alignment openings  62  and  64  are round and alignment opening  60  is oval shaped. The alignment projections and alignment openings are shown as round or oval shaped, but any other suitable shape for the alignment projections and alignment openings may be used. Alignment projections  50 ,  52  and  54  and alignment openings  60 ,  62  and  64  are used for joining and aligning two or more modular receptacles  30  together as discussed below. 
     The modular print cartridge receptacles  30 , in addition to providing mechanical alignment and electrical interconnection also provides other functionalities through the print driver ASIC located on the modular print cartridge receptacle. These functionalities include: (1) controlled and accurate pulse firing energy for the print cartridge, (2) electrical pulse driving, (3) automatic pulse warming, (4) ambient temperature measurement, (5) printhead temperature measurement, (6) ESD protection (7) detection of, and protection from, open circuit and shorts, and (8) other servicing functions normally used to support inkjet print cartridges. These integrated features of modular print cartridge receptacle  30  allow for the easy development of specialized printing systems without the need for a thorough knowledge of thermal inkjet technology. Accordingly, the specialized printing system must only perform the following functions: (1) set the print cartridge firing energy level (the print driver ASIC ensures accurate deliver of that energy level), (2) set the firing order of the print cartridge, (3) set the time when the print cartridge is fired by providing a logic timing signal along with which nozzles are to be fired, and (4) set the pulse width of the firing pulse. 
     For additional details regarding print cartridge control see U.S. patent application Ser. No. 08/958,951, filed Oct. 28, 1997, entitled “Thermal Ink Jet Print Head and Printer Energy Control Apparatus and Method,” U.S. Pat. No. 5,418,558, entitled “Determining the Operating Energy of a Thermal Ink Jet Printhead Using an Onboard Thermal Sense Resistor;” U.S. Pat. No. 5,428,376, entitled “Thermal Turn on Energy Test for an Inkjet Printer;” and U.S. Pat. No. 5,682,185 entitled “Energy Management Scheme for an Ink Jet Printer;” The foregoing commonly assigned patents and patent applications are herein incorporated by reference. 
     The modular print cartridge receptacles  30  may be assembled in various configurations, only some of which are described below. One skilled in the art will readily see other possible combinations. First, modular print cartridge receptacles  30  may be assembled in an aligned arrangement into a modular print cartridge receptacle assembly  70 . To assemble modular print cartridge receptacles assembly  70  in an aligned arrangement, alignment projections  50  and  54  are aligned and inserted into alignment openings  60  and  64 , respectively, in the exterior left sidewall  36  of a second modular receptacle  30 . FIG. 7 is a perspective view of four modular print cartridge receptacles  30  assembled in an aligned arrangement into a modular print cartridge receptacle assembly  70  and showing one print cartridge installed in the modular assembly. 
     Second, modular print cartridge receptacles  30  may be assembled in a staggered arrangement into a modular print cartridge receptacle assembly  70 . To assemble modular print cartridge receptacles assembly  70  in an aligned arrangement, alignment projections  52  and  54  are aligned and inserted into alignment openings  60  and  62 , respectively, in the exterior left sidewall  36  of a second modular receptacle  30 . FIG. 8 is a perspective view of four modular print cartridge receptacles assembled in a staggered arrangement into a modular print cartridge receptacle assembly. Precise alignment of the nozzle plates on different cartridges installed in different modular receptacles  30  is achieved by the precise location of alignment projections  50 ,  52  and  54  and alignment openings  60 ,  62  and  64 . 
     The present invention makes the alignment between print cartridges simple and inexpensive since the print cartridge  10  machined datums  24 - 27  align print cartridge  10  precisely in modular receptacle  30  as described above. Accurate alignment between print cartridges located in adjacent modular receptacles  30  after assembly into a modular print cartridge assembly  70  is achieved by the precise alignment features of alignment projections  50 ,  52  and  54  and alignment openings  60 ,  62  and  64 . 
     Modular print cartridge receptacles  30  may be assembled together in various configurations including combinations of both staggered and aligned modular print cartridge receptacles  30 . Modular print cartridge receptacles  30  may be assembled together with either monochrome or multiple color ink print cartridges depending upon the printing system. FIG. 9 is a plan view of some different possible assembled configurations of modular print cartridge receptacles  30  and associated print cartridges as viewed upward from below the print cartridges to show the nozzle array  16 . In an aligned arrangement, the each orifice, or nozzle,  17  in nozzle array  16  is aligned with the corresponding nozzle in the other print cartridges  10 . In a staggered arrangement, the orifices  17  in nozzle array  16  are aligned such that the top nozzle in one print cartridge is aligned with the bottom nozzle in the adjacent print cartridge  10 . Alternatively, in a staggered arrangement, the orifices  17  in nozzle array  16  are overlapped such that the top nozzles in one print cartridge is aligned with a nozzle above the bottom nozzle in the adjacent print cartridge  10 . In this case electronic alignment through selective on/off control of individual nozzles may also be utilized. 
     FIG. 9 ( a ) shows four modular print cartridge receptacles  30  and associated print cartridges  10  assembled in a fully aligned arrangement into a modular print cartridge receptacle assembly  70 . Any number of modular print cartridge receptacles  30  and associated print cartridges  10  may be assembled in this arrangement and may include any colors desired. FIG. 9 ( b ) shows four modular print cartridge receptacles  30  and associated print cartridges  10  assembled in a fully staggered arrangement into a modular print cartridge receptacle assembly  70  having a swath width essentially equal to four individual print cartridges. Obviously, any number of modular print cartridge receptacles  30  and associated print cartridges  10  could be assembled in a fully staggered arrangement to provide a desired print swath width. FIG. 9 ( c ) shows eight modular print cartridge receptacles  30  and associated print cartridges  10  assembled into a combination aligned and staggered modular print cartridge receptacle assembly  70 . Obviously, any number of modular print cartridge receptacles  30  and associated print cartridges  10  could be assembled as in FIG. 9 ( c ) to provide a desired print swath width. The arrangements shown in FIG. 9 are merely illustrative of the many possible combinations of staggered, aligned and the number of modular print cartridge receptacles  30  assembled into a modular print cartridge receptacle assembly  70 . 
     Accordingly, the present invention provides for variable width printing up to and including full page width printing. When using a single print cartridge for monochrome printing, the width of printing is determined by the length of the nozzle portion of the print cartridge. The present invention provides for mounting multiple print cartridges  10  through the use of modular print cartridge receptacles  30  in order to easily provide variable width printing. As many print cartridges  10  and modular print cartridge receptacles  30  may be assembled into a modular print cartridge receptacle assembly  70  as is necessary to achieve the desired print width. Greater throughput is possible by using wider print widths across the print media. 
     FIGS. 10 and 11 are simplified schematic perspective views of one embodiment of an inkjet printer  80  suitable for utilizing the modular print cartridge assembly  70  showing print cartridges installed and without print cartridges installed, respectively. A traversing mechanism for modular print cartridge assembly  70  generally may includes slide rods  82  along which modular print cartridge receptacle assembly  70  moves back and forth through the print zone  84  and out of the print zone to the service station  94  and capping station  96 . Modular print cartridge receptacle assembly  70  is may be movably attached to slide rod  82  with a split bushing  86 , or any other suitable means of attachment. Alternatively, the bottom of the modular print cartridge receptacle assembly  70  can be mounted to a horizontal base  87  to which split bushing  86  is also mounted. It will be appreciated that other means for supporting and traversing the modular print cartridge receptacle assembly  70  above the media are within the scope of the present invention. The modular print cartridge assembly  70  its self or any additional means for supporting the modular print cartridge assembly  70  may be referred to as a modular print cartridge receptacle assembly support structure or a carriage. 
     A motor  88  may be used to provide the capability of traversing the modular print cartridge receptacle assembly  70  across a print zone on the media. The motor  88  may be connected to a conventional drive belt  90  and pulley  91  arrangement, or to a screw drive mechanism (not shown), which is connected to modular print cartridge receptacle assembly  70  or to horizontal base  87 . This arrangement can be used to traverse the modular print cartridge receptacle assembly  70  back and forth through the appropriate print zone position  84  in the path of the media  92  and also to move the modular print cartridge receptacle assembly  70  to the print cartridge service station  94  for servicing and the print cartridge capping station  96  for storage. 
     When a printing operation is initiated, the sheet of media  92  is fed into printer  80  and the media is moved through the print zone  84  by a media moving mechanism  98 . The media moving mechanism  98  to move the media  92  may be, for example, either a belt drive or a roller drive which moves the media through the print zone only one time. Generally, in this situation the modular print cartridge receptacle assembly  70  has the number of modular print cartridge receptacles needed for a print swath of the desired width and the modular print cartridge receptacle assembly  70  is stationary during printing. In these embodiments the modular print cartridge receptacle assembly  70  is stationary during printing while the media  92  is passed through the print zone. When the printing is complete, the sheet is moved by the media moving mechanism  98  to a position out of the print zone  84 . The mechanism for traversing the modular print cartridge assembly  70  and the media moving mechanism may be conventionally used mechanisms. 
     Alternatively, in another embodiment, the media moving mechanism  98  may be a rotating drum to which the media  92  is temporarily held and the drum rotates the media through the print zone  84 . In this embodiment the media may be moved through the print zone once, i.e., one drum rotation, or multiple times, i.e., multiple drum rotations before the paper is released to the output tray  99 . In this embodiment the modular print cartridge receptacle assembly  70  may be either stationary with a desired print swath with corresponding number of modular print cartridge receptacles, or the modular print cartridge receptacle assembly  70  may be traversing across the media during the printing operation. 
     A flexible circuit (not shown) provides for transmitting electrical signals from the printer&#39;s microprocessor to the electrical interconnects  49  on the individual modular print cartridge receptacles in the modular print cartridge receptacle assembly  70 . The features of inkjet printer  80  may include an ink delivery system from an onboard ink supply internal to the print cartridge  10  or from tubes connected to an off-axis ink supply as shown in the embodiment shown in FIG.  12 . 
     FIG. 12 is a perspective view of another embodiment of an inkjet printer  100  suitable for utilizing the modular print cartridge receptacle assembly  70 . When a printing operation is initiated, a sheet of media from input tray  112  is fed into printer  100  using a sheet feeder, then brought around in a U direction to now travel in the opposite direction toward output tray  113 . The media is stopped and a carriage  116 , which supports a modular print cartridge receptacle assembly  70  containing one or more modular print cartridge receptacles  30 , is then traversed across the media for printing a swath of ink on the media in a print zone  114 . After a single traverse or multiple traverses, the media is then incrementally shifted using a conventional stepper motor and feed rollers to a next position within the print zone  114 , and carriage  116  again traverses across the media for printing a next swath of ink. When the printing on the media is complete, the sheet is forwarded to a position above output tray  113 , held in that position to ensure the ink is dry, and then released. 
     The carriage  116  mechanism may be conventional and generally includes a slide rod  122 , along which carriage  116  slides, a flexible circuit (not shown in FIG. 12) for transmitting electrical signals from the printer&#39;s microprocessor individually to the modular print cartridge receptacles  30  comprising the modular print cartridge receptacle assembly  70 . A stepper motor (not shown), connected to carriage  116  using a conventional drive belt and pulley arrangement, is used for transporting carriage  116  along slide rod  122  across print zone  114 . 
     The features of inkjet printer  100  may include an ink delivery system for providing ink to the print cartridges  10  from an off-axis ink supply station  130  containing replaceable ink supply cartridges  131 ,  132 ,  133 , and  134 . Tubes  136  carry ink from the four replaceable ink supply cartridges  131 - 134  to the print cartridges  10 . Alternatively, inkjet printer  100  may include an ink delivery system from an onboard ink supply internal to the print cartridge  10 . 
     Accordingly, the modular print cartridge assembly  70  may be used in many different embodiments such as (1) moving the media past a stationary modular print cartridge assembly, (2) moving the media past a traversing modular print cartridge assembly and (3) traversing a modular print cartridge assembly across a stationary media, above happening during the printing operation. 
     As a result of these design options, the modular print cartridge receptacle offers a wide range of product implementations other than those illustrated in FIGS. 10,  11  and  12 . For example, such modular print cartridge receptacles systems may be incorporated into an inkjet printer used in a large format printer, facsimile machine, copier or a combined facsimile/copier. 
     While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made within departing from this invention in its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as fall within the true spirit and scope of this invention.