Abstract:
A printer module includes an elongate body. A motor assembly is operatively mounted to an end of the body. A quartet of rollers is rotationally mounted with respect to the body and extends along the inside of the body. The rollers include a pair of driven rollers coupled to the motor assembly and a pair of free rotation neutral rollers. The rollers are arranged in pinching pairs with each pair including a respective driven and neutral roller. An elongate printhead is operatively mounted to extend along the body, and is configured to print ink upon print media passing through the body and between the pairs of rollers.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   The present application is a Continuation of U.S. application Ser. No. 10/975,458 filed on Oct. 29, 2004, now issued U.S. Pat No. 7,222,939, which is a Continuation of U.S. application Ser. No. 10/636,250, filed on Aug. 8, 2003, now issued U.S. Pat. No. 7,083,254, which is a Divisional of U.S. application Ser. No. 09/575,182, filed on May 23, 2000, now issued U.S. Pat. No. 6,924,907, all of which are herein incorporated by reference. 

   FIELD OF THE INVENTION 
   The invention relates to a compact printer system able to print full-color, business card size documents from a device about the size of a pen. The system includes various hot-connectable modules that provide a range of functions. In particular the invention relates to a compact color printer that provides a print function for the compact printer system. 
   Reference may be had to co-pending applications claiming priority from Australian Provisional Patent Application number PQ0560 dated 25 May 1999. The co-pending applications describe related modules and methods for implementing the compact printer system. The co-pending applications are as follows: 
   
     
       
             
             
             
           
         
             
                 
             
             
               USSN 
               Docket No. 
               Title 
             
             
                 
             
           
           
             
               6,712,452 
               PP02 
               Modular Compact Printer System 
             
             
               6,416,160 
               PP03 
               Nozzle Capping Mechanism 
             
             
               6,238,043 
               PP04 
               Ink Cartridge for Compact Printer System 
             
             
               6,958,826 
               PP07 
               Controller for Printer Module 
             
             
               6,812,972 
               PP08 
               Camera Module for Compact Printer System 
             
             
               6,553,459 
               PP10 
               Memory Module for Compact Printer System 
             
             
               6,967,741 
               PP11 
               Effects Module for Compact Printer System 
             
             
               6,956,669 
               PP12 
               Effects Processor for Effects Module 
             
             
               6,903,766 
               PP13 
               Timer Module for Compact Printer System 
             
             
               6,804,026 
               PP15 
               Color Conversion Method for Compact 
             
             
                 
                 
               Printer System 
             
             
               09/575,120 
               PP16 
               Method and Apparatus of Dithering 
             
             
               6,975,429 
               PP17 
               Method and Apparatus of Image Conversion 
             
             
                 
             
           
        
       
     
   
   BACKGROUND OF THE INVENTION 
   Microelectronic manufacturing techniques have led to the miniaturization of numerous devices. Mobile phones, personal digital assistant devices, and digital cameras are very common examples of the miniaturization trend. 
   One device that has not seen the advantage of microelectronic manufacturing techniques is the printer. Commercially available printers are large compared to many of the devices they could support. For instance, it is impractical to carry a color printer for the purpose of instantly printing photographs taken with known compact digital cameras. 
   A compact printhead has been described in co-pending United States Patent Applications filed simultaneously to the present application and hereby incorporated by cross reference: 
   
     
       
             
             
             
           
         
             
                 
             
             
               USSN 
               Docket No. 
               Title 
             
             
                 
             
           
           
             
               7,018,016 
               MJ62 
               Fluidic seal for an ink jet nozzle assembly 
             
             
               6,428,133 
               IJ52 
               Ink jet printhead having a moving nozzle with 
             
             
                 
                 
               an externally arranged actuator 
             
             
               6,526,658 
               IJM52 
               Method of manufacture of an ink jet 
             
             
                 
                 
               printhead having a moving nozzle with 
             
             
                 
                 
               an externally arranged actuator 
             
             
               6,328,417 
               MJ63 
               Ink jet printhead nozzle array 
             
             
               6,390,591 
               MJ58 
               Nozzle guard for an ink jet printhead 
             
             
                 
             
           
        
       
     
   
   SUMMARY OF THE INVENTION 
   In one form, the invention resides in a printer module for a compact printer system comprising: 
   an elongate body; 
   a stationary printhead housed within said body; 
   means for moving a printable media past said stationary printhead; 
   an ink reservoir within said body and communicating with said printhead; 
   means within said body for storing an image to be printed by said printhead; and 
   means for transferring said image to said printhead; 
   said printhead printing said image on substantially the full width of said printable media in a single pass. 
   According to an embodiment of the present invention there is provided a capping device for a printer having a printhead and at least one media feed roller, said capping device movable between an open position, in which the printhead may deposit ink on print media, and a closed position, in which the capping device blocks the printhead from depositing ink on said media, said capping device being operatively connected to the at least one media feed roller whereby motion of said feed roller moves the capping device between said open and closed position. 
   Preferably, the capping device is connected to the at least one roller via a clutch. 
   Preferably, the clutch is a friction clutch. 
   Further features of the invention will be evident from the following description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order to assist with describing preferred embodiments of the invention, reference will be made to the following figures in which: 
       FIG. 1  is a printer module; 
       FIG. 2  is a camera module; 
       FIG. 3  is a memory module; 
       FIG. 4  is a communication module; 
       FIG. 5  is a flash module; 
       FIG. 6  is a timer module; 
       FIG. 7  is a laser module; 
       FIG. 8  is an effects module; 
       FIG. 9  is a characters module; 
       FIG. 10  is an adaptor module; 
       FIG. 11  is a pen module; 
       FIG. 12  is a dispenser module; 
       FIG. 13  is a first compact printer configuration; 
       FIG. 14  is a second compact printer configuration; 
       FIG. 15  is a third compact printer configuration; 
       FIG. 16  is a fourth compact printer configuration; 
       FIG. 17  is an exploded view of the Printer Module of  FIG. 1 ; 
       FIG. 18  is a top view of the Printer Module with ink cartridge removed; 
       FIG. 19  is a cross-sectional view through AA in  FIG. 18 ; and 
       FIG. 20  is a block circuit diagram of a controller for the printer module. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 to 12 , there are shown various modules that together form a compact printer system. Individual modules can be attached and detached from the compact printer configuration to allow a user-definable solution to business-card sized printing. Images can also be transferred from one compact printer to another without the use of a secondary computer system. Modules have a minimal user-interface to allow straightforward interaction. 
   A compact printer system configuration consists of a number of compact printer modules connected together. Each compact printer module has a function that contributes to the overall functionality of the particular compact printer configuration. Each compact printer module is typically shaped like part of a pen, physically connecting with other compact printer modules to form the complete pen-shaped device. The length of the compact printer device depends on the number and type of compact printer modules connected. The functionality of a compact printer configuration depends on the compact printer modules in the given configuration. 
   The compact printer modules connect both physically and logically. The physical connection allows modules to be connected in any order, and the logical connection is taken care of by the compact printer Serial Bus—a bus that provides power, allows the modules to self configure and provides for the transfer of data. 
   In terms of physical connection, most compact printer modules consist of a central body, a male connector at one end, and a female connector at the other. Since most modules have both a male and female connector, the modules can typically be connected in any order. Certain modules only have a male or a female connector, but this is determined by the function of the module. Adaptor modules allow these single-connector modules to be connected at either end of a given compact printer configuration. 
   A four wire physical connection between all the compact printer modules provides the logical connection between them in the form of the compact printer Serial Bus. The compact printer Serial Bus provides power to each module, and provides the means by which data is transferred between modules. Importantly, the compact printer Serial Bus and accompanying protocol provides the means by which the compact printer system auto-configures, reducing the user-interface burden on the end-user. 
   Compact printer modules can be grouped into three types:
         image processing modules including a Printer Module ( FIG. 1 ), a Camera Module ( FIG. 2 ), and a Memory Module ( FIG. 3 ). Image processing modules are primarily what sets the compact printer system apart from other pen-like devices. Image processing modules capture, print, store or manipulate photographic images;   housekeeping modules including an Adapter Module ( FIG. 10 ), an Effects Module ( FIG. 8 ), a Communications Module ( FIG. 4 ), and a Timer Module ( FIG. 6 ). Housekeeping modules provide services to other modules or extended functionality to other modules; and   isolated modules including a Pen Module ( FIG. 11 ) and a Laser Module ( FIG. 7 ). Isolated modules are those that attach to the compact printer system but are completely independent of any other module. They do not necessarily require power, and may even provide their own power. Isolated Modules are defined because the functionality they provide is typically incorporated into other pen-like devices.       

   Although housekeeping modules and isolated modules are useful components in a compact printer system, they are extras in a system dedicated to image processing and photographic manipulation. Life size (1:1) illustrations of the compact printer modules are shown in  FIGS. 1 to 12 , and example configurations produced by connecting various modules together are shown in  FIGS. 13 to 16 . 
     FIG. 1  shows a printer module that incorporates a compact printhead described in co-pending United States Patent Applications listed in the Background section of this application, incorporated herewith by reference, and referred to herewith as a Memjet printhead. The Memjet printhead is a drop-on-demand 1600 dpi inkjet printer that produces bi-level dots in up to 4 colors to produce a printed page of a particular width. Since the printhead prints dots at 1600 dpi, each dot is approximately 22.5 μm in diameter, and spaced 15.875 μm apart. Because the printing is bi-level, the input image should be dithered or error-diffused for best results. Typically a Memjet printhead for a particular application is page-width. This enables the printhead to be stationary and allows the paper to move past the printhead. A Memjet printhead is composed of a number of identical ½ inch Memjet segments. 
   The printer module  10  comprises a body  11  housing the Memjet printhead. Power is supplied by a three volt battery housed in battery compartment  12 . The printhead is activated to commence printing when a business card (or similar sized printable media) is inserted into slot  13 . Male connector  14  and female connector  15  facilitate connection of other modules to the printer module  10 . 
     FIG. 2  shows a camera module  20 . The camera module provides a point-and-shoot camera component to the compact printer system as a means of capturing images. The camera module comprises a body  21  having a female connector  22 . A lens  23  directs an image to an image sensor and specialized image processing chip within the camera  24 . A conventional view finder  25  is provided as well as a lens cap  26 . An image is captured when the Take button  27  is pushed. Captured images are transferred to the Printer Module  10  for subsequent printing, manipulation, or storage. The Camera Module also contains a self-timer mode similar to that found on regular cameras. 
     FIG. 3  shows a Memory Module  30  comprising a body  31 , LCD  32 , IN button  33 , OUT button  34  and SELECT button  35 . The Memory Module  30  is a standard module used for storing photographic images captured by the Camera  20 . The memory module stores  48  images, each of which can be accessed either at full resolution or at thumbnail resolution. Full resolution provides read and write access to individual images, and thumbnail resolution provides read access to  16  images at once in thumbnail form. 
   The Memory Module  30  attaches to other modules via a female connector  36  or male connector  37 . The male and female connectors allow the module to be connected at either end of a configuration. Power is provided from the Printer Module  10  via the Serial Bus. 
   A Communications Module  40  is shown in  FIG. 4 . The communications module  40  consists of a connector  41  and a cable  42  that terminates in an appropriate connector for a computer port, such as a USB port, RS232 serial port or parallel port. The Communications Module  40  allows the compact printer system to be connected to a computer. When so connected, images can be transferred between the computer and the various modules of the compact printer system. The communications module allows captured images to be downloaded to the computer, and new images for printing to be uploaded into the printer module  10 . 
   A Flash Module  50  is shown in  FIG. 5 . The Flash Module  50  is used to generate a flash with flash cell  51  when taking photographs with the Camera Module  20 . The Flash Module attaches to other modules via female connector  52  and male connector  53 . It contains its own power source. The Flash Module is automatically selected by the Camera Module when required. A simple switch allows the Flash Module to be explicitly turned off to maximize battery life. 
     FIG. 6  shows a Timer Module  60  that is used to automate the taking of multiple photos with the Camera Module  20 , each photo separated by a specific time interval. The captured photos are stored in Memory Module  30 . Any flash requirements are handled by the Camera Module  20 , and can therefore be ignored by the Timer Module. The Timer Module  60  consists of a body  61  housing a LCD  62 , START/STOP button  63  and UNITS button  64 . A SELECT button  65  allows the user to select time units and the number of units are set by UNITS button  64 . The Timer Module  60  includes a male connector  66  and female connector  67 . The Timer Module takes its power from the Printer Module  10  via the Serial Bus. 
   A Laser Module  70  is shown in  FIG. 7 . The Laser Module  70  consists of a body  71  containing a conventional laser pointer operated by button  72 . As the Laser Module is a terminal module it only has one connector, which in the example is a male connector  73 . The Laser Module is an isolated module, in that it does not perform any image capture, storage, or processing. It exists as a functional addition to the compact printer system. It is provided because laser pointer services are typically incorporated into other pen-like devices. The Laser Module contains its own power supply and does not appear as a device on the Serial Bus. 
   The Effects Module shown in  FIG. 8  is an image processing module. It allows a user to select a number of effects and applies them to the current image stored in the Printer Module  10 . The effects include borders, clip-art, captions, warps, color changes, and painting styles. The Effects Module comprises a body  81  housing custom electronics and a LCD  82 . A CHOOSE button  83  allows a user to choose between a number of different types of effects. A SELECT button  84  allows the user to select one effect from the number of effects of the chosen type. Pressing the APPLY button  85  applies the effect to image stored in the Printer Module  10 . The Effects Module obtains power from the Serial Bus. Male connector  86  and female connector  87  allow the Effects Module to be connected to other compact printer system modules. 
     FIG. 9  shows a Character Module  90  that is a special type of Effects Module (described above) that only contains character clip-art effects of a given topic or genre. Examples include The Simpsons®, Star Wars®, Batman®, and Dilbert® as well as company specific modules for McDonalds® etc. As such it is an image processing module. It consists of a body  91  housing custom electronics and a LCD  92 . SELECT button  93  allows the user to choose the effect that is to be applied with APPLY button  94 . The Character Module obtains power from the Serial Bus through male connector  95  and female connector  96 . 
   The Adaptor Module  100 , shown in  FIG. 10 , is a female/female connector that allows connection between two modules that terminate in male connectors. A male/male connector (not shown) allows connection between two modules that terminate in female connectors. The Adaptor Module is a housekeeping module, in that it facilitates the use of other modules, and does not perform any specific processing of its own. 
   All “through” modules have a male connector at one end, and a female connector at the other end. The modules can therefore be chained together, with each module connected at either end of the chain. However some modules, such as the Laser Module  70 , are terminating modules, and therefore have either a male or female connector only. Such single-connector modules can only be connected at one end of the chain. If two such modules are to be connected at the one time, an Adaptor Module  100  is required. 
     FIG. 11  shows a Pen Module  110  which is a pen in a module form. It is an isolated module in that it attaches to the compact printer system but is completely independent of any other module. It does not consume or require any power. The Pen Module is defined because it is a convenient extension of a pen shaped, pen sized device. It may also come with a cap  111 . The cap may be used to keep terminating connectors clean in the case where the chain ends with a connector rather than a terminating module. 
   To assist with accurately feeding a business card sized print media into slot  13  of the printer module  10 , a dispenser module  120  is provided as shown in  FIG. 12 . The dispenser module  120  comprises a body  121  that holds a store of business card sized print media. A Printer Module  10  locates into socket  122  on the dispenser module  120 . When correctly aligned, a card dispensed from the dispenser module by slider  123  enters slot  13  and is printed. 
   In the sense that a minimum configuration compact printer system must be able to print out photos, a minimum compact printer configuration contains at least a Printer Module  10 . The Printer Module holds a single photographic image that can be printed out via its Memjet printer. It also contains the 3V battery required to power the compact printer system. 
   In this minimum configuration, the user is only able to print out photos. Each time a user inserts a business card  130  into the slot in the Printer Module, the image in the Printer Module is printed onto the card. The same image is printed each time a business card is inserted into the printer. In this minimum configuration there is no way for a user to change the image that is printed. The dispenser module  120  can be used to feed cards  130  into the Printer Module with a minimum of fuss, as shown in  FIG. 13 . 
   By connecting a Camera Module  20  to the minimum configuration compact printer system the user now has an instant printing digital camera in a pen, as shown in  FIG. 14 . The Camera Module  20  provides the mechanism for capturing images and the Printer Module  10  provides the mechanism for printing them out. The battery in the Printer Module provides power for both the camera and the printer. 
   When the user presses the “Take” button  27  on the Camera Module  20 , the image is captured by the camera  24  and transferred to the Printer Module  10 . Each time a business card is inserted into the printer the captured image is printed out. If the user presses “Take” on the Camera Module again, the old image in the Printer Module is replaced by the new image. 
   If the Camera Module is subsequently detached from the compact printer system, the captured image remains in the Printer Module, and can be printed out as many times as desired. The Camera Module is simply there to capture images to be placed in the Printer Module. 
     FIG. 15  shows a further configuration in which a Memory Module  30  is connected to the configuration of  FIG. 14 . In the embodiment of  FIG. 15 , the user has the ability to transfer images between the Printer Module  10  and a storage area contained in the Memory Module  30 . The user selects the image number on the Memory Module, and then either sends that image to the Printer Module (replacing whatever image was already stored there), or brings the current image from the Printer Module to the specified image number in the Memory Module. The Memory Module also provides a way of sending sets of thumbnail images to the Printer Module. 
   Multiple Memory Modules can be included in a given system, extending the number of images that can be stored. A given Memory Module can be disconnected from one compact printer system and connected to another for subsequent image printing. 
   With the Camera Module  20  attached to a Memory Module/Printer Module compact printer system, as shown in  FIG. 15 , the user can “Take” an image with the Camera Module, then transfer it to the specified image number in the Memory Module. The captured images can then be printed out in any order. 
   By connecting a Communications Module  40  to the minimum configuration compact printer system, the user gains the ability to transfer images between a PC and the compact printer system.  FIG. 16  shows the configuration of  FIG. 15  with the addition of a Communications Module  40 . The Communications Module makes the Printer Module  10  and any Memory Modules  30  visible to an external computer system. This allows the download or uploading of images. The communications module also allows computer control of any connected compact printer modules, such as the Camera Module  20 . 
   In the general case, the Printer Module holds the “current” image, and the other modules function with respect to this central repository of the current image. The Printer Module is therefore the central location for image interchange in the compact printer system, and the Printer Module provides a service to other modules as specified by user interaction. 
   A given module may act as an image source. It therefore has the ability to transfer an image to the Printer Module. A different module may act as an image store. It therefore has the ability to read the image from the Printer Module. Some modules act as both image store and image source. These modules can both read images from and write images to the Printer Module&#39;s current image. 
   The standard image type has a single conceptual definition. The image definition is derived from the physical attributes of the printhead used in the Printer Module. The printhead is 2 inches wide and prints at 1600 dpi in cyan, magenta and yellow bi-level dots. Consequently a printed image from the compact printer system is 3200 bi-level dots wide. 
   The compact printer system prints on business card sized pages (85 mm×55 mm). Since the printhead is 2 inches wide, the business cards are printed such that 1 line of dots is 2 inches. 2 inches is 50.8 mm, leaving a 2 mm edge on a standard business-card sized page. The length of the image is derived from the same card size with a 2 mm edge. Consequently the printed image length is 81 mm, which equals 5100 1600 dpi dots. The printed area of a page is therefore 81 mm×51 mm, or 5100×3200 dots. 
   To obtain an integral contone to bi-level ratio a contone resolution of 267 ppi (pixels per inch) is chosen. This yields a contone CMY page size of 850×534, and a contone to bi-level ratio of 1:6 in each dimension. This ratio of 1:6 provides no perceived loss of quality since the output image is bi-level. 
   The printhead prints dots in cyan, magenta, and yellow ink. The final output to the printed page must therefore be in the gamut of the printhead and take the attributes of the inks into account. It would at first seem reasonable to use the CMY color space to represent images. However, the printer&#39;s CMY color space does not have a linear response. This is definitely true of pigmented inks, and partially true for dye-based inks. The individual color profile of a particular device (input and output) can vary considerably. Image capture devices (such as digital cameras) typically work in RGB (red green blue) color space, and each sensor will have its own color response characteristics. 
   Consequently, to allow for accurate conversion, as well as to allow for future image sensors, inks, and printers, the CIE L*a*b* color model [CIE, 1986, CIE 15.2 Colorimetry: Technical Report (2 nd  Edition), Commission Internationale De l&#39;Eclairage] is used for the compact printer system. L*a*b* is well defined, perceptually linear, and is a superset of other traditional color spaces (such as CMY, RGB, and HSV). 
   The Printer Module must therefore be capable of converting L*a*b* images to the particular peculiarities of its CMY color space. However, since the compact printer system allows for connectivity to PCs, it is quite reasonable to also allow highly accurate color matching between screen and printer to be performed on the PC. However the printer driver or PC program must output L*a*b*. 
   Each pixel of a compact printer image is therefore represented by 24 bits: 8 bits each of L*, a*, and b*. The total image size is therefore 1,361,700 bytes (850×534×3). 
   Each image processing module is able to access the image stored in the Printer Module. The access is either to read the image from the Printer Module, or to write a new image to the Printer Module. 
   The communications protocol for image access to the Printer Module provides a choice of internal image organization. Images can be accessed either as 850×534 or as 534×850. They can also be accessed in interleaved or planar format. When accessed as interleaved, each pixel in the image is read or written as 24 bits: 8 bits each of L*, a*, b*. When accessed as planar, each of the color planes can be read or written independently. The entire image of L* pixels, a* pixels or b* pixels can be read or written at a time. 
   Detailed views of the Printer Module  10  are shown in  FIGS. 17 ,  18  and  19 . The Printer Module  10  is the central module in the compact printer system. It contains a 2-inch Memjet printhead  16 , a Cyan/Magenta/Yellow ink cartridge  17 , the current image stored in flash memory on the printhead, and a power source in the form of a 3V battery  12   a  in the battery compartment  12 . With regards to processing, the Printer Module  10  contains a controller chip (or chips)  101  that controls printing of the stored image in high quality. 
   The Printer Module  10  can be used as a stand-alone printer of a single image (such as business cards), or can be used in conjunction with other modules to print a variety of images. 
   Looking in detail at  FIG. 17 , the body  11  of the printer module is in three parts being a lid  11   a , base  11   b , and chassis  11   c . Printhead  16  with filter  16   a  fits into the chassis  11   c . Powered rollers  18   a  are driven by motor and gearbox  103 . Neutral rollers  18   b  fit into ink cartridge  17  and guide a card past the printhead  16 . Springs  18   c  ( FIG. 19 ) urge the neutral rollers  18   b  towards the powered rollers  18   a . The ink cartridge  17  is located beyond the rollers  18  so that the card passes between the printhead  16  and the ink cartridge  17 . Ink inlets  105  provide communication between the ink cartridge  17  and the printhead  16 . Micro-moulded channels  106  in the chassis  11   c  distribute the ink from the ink inlets  105  to the length of the printhead  16 . 
   Serial bus  104  provides power and data between the printer module  10  and other modules connected to male connector  14  and female connector  15 . The serial bus  104  picks up power from the battery  12   a  and signals from the controller  101 . Looking at  FIG. 19 , to print an image, a user simply inserts a business card into the input slot  13  of the Printer Module. Sensor  102  detects the insertion and a small motor  103   a  and gearbox  103   b  activates rollers  18  to carry the card through the module. A tab film  107  provides signal connection from the sensor  102  to the controller  101  and hence to the motor and gearbox  103 . A wedge  108  holds the tab film  107  in place to make a signal connection. 
   The printed card is ejected from the output slot  13   a  of the module over a time period of 1 second. There is no on/off switch—the act of inserting the card is the effective “on” switch for the duration of a print. 
   To reduce the chance of ink drying in the printhead  16  a capping mechanism  19  is provided to cap the ink nozzles in the printhead. The capping mechanism  19  comprises a capping arm  191  supporting a blotter  192  with adjacent elastomeric seals  193 . A clutch  194  is operatively associated with one of the powered rollers  18   a  to move the capping arm  191  out of the path of the card for printing. 
   The volume of ink present in an ink cartridge is 450 ml (2 mm×3 mm×75 mm), enough to produce 450 million dots of a given color. The exact number of images that can be printed before replacement will depend on the color composition of those images. 450 ml represents:
         25 full black cards (black requires all three colors to be used)   50 full sized photos at 50% CMY coverage   111 typical photo/text cards at 22.5% CMY coverage   166 cards of black (CMY) text at 15% coverage       

   A QA chip in the ink cartridge keeps track of how much ink has been used. Sensors in the ink cartridge provide signals to the QA chip that are transferred to the controller  101  via contacts  109 . If there is insufficient ink of any color to print a given image, the card will pass through the printer module, but nothing will be printed. 
   It is a simple matter to replace the old ink cartridge  17  by sliding latch  171 , removing lid  11   a , unclipping the old cartridge and clipping on a new one. 
   A schematic of a suitable controller  101  is shown in  FIG. 20 . The controller may be embodied in a single application specific integrated circuit or in a number of discrete elements. The controller  101  includes a simple micro-controller CPU core  201  with associated program ROM  202  and program RAM  203 . The CPU  201  communicates with the other units within the controller via memory-mapped I/O supported by a Memory Decoder  204 . The Decoder  204  translates data addresses into internal controller register accesses over the internal low speed bus  205 , and therefore allows for memory mapped I/O of controller registers. The bus  205  includes address lines  205   a  and data or control lines  205   b.    
   An optional Serial Bus interface  206 , is connected to the internal chip low-speed bus  205  and connects to the Serial Bus for communication with other modules. A parallel interface  207  provides communication to the motor and gearbox  103  in the printer module  10 . It can also receive signals from buttons, such as a paper sensor  102 . 
   There are two optional low-speed serial interfaces  208 ,  209  connected to the internal low-speed bus  205 . A first interface  208  connects to the QA chip  220  in the ink cartridge of the printer module  10 . The second interface connects to a QA chip  221  on the print module  10 . The reason for having two interfaces is to connect to both the on-module QA Chip  221  and to the ink cartridge QA Chip  220  using separate lines to improve security. If only a single line is used, a clone ink cartridge manufacturer could usurp the authentication mechanism and provide a non-proprietary cartridge. 
   The total amount of memory required for the interleaved linear CMY/L*a*b* image is 1,361,700 bytes (approximately 1.3 MB). The image is written to Image Storage Memory  211  by the Image Access Unit  212 , and read by both the Image Access Unit  212  and the Printhead Interface (PHI)  210 . The CPU does not have direct random access to this image memory. It must access the image pixels via the Image Access Unit  212 . The Printhead Interface  210  is the means by which the controller loads the printhead  16  with the dots to be printed, and controls the actual dot printing process. 
   The controller  101  may also include a clock phase-locked loop  213  that provides timing signals to the controller. The clock  213  draws a base signal from crystal oscillator  214 . Some CPU include a clock so the clock and crystal would not be required. 
   A standard JTAG (Joint Test Action Group) Interface  215  is included in the controller for testing purposes. Due to the complexity of the controller, a variety of testing techniques are required, including BIST (Built In Self Test) and functional block isolation. An overhead of 10% in chip area is assumed for overall chip testing circuitry. 
   The battery used to power the compact printer system is a CR1/3N cell. The battery contains enough power to print 133 photos. The characteristics of the battery are listed in the following table. 
   
     
       
             
             
             
           
         
             
                 
                 
             
             
                 
               Parameter 
               Value 
             
             
                 
                 
             
           
           
             
                 
               Type Designation 
               CR1/3N 
             
             
                 
               Voltage (V) 
               3 
             
             
                 
               Electrochemical System 
               Lithium 
             
             
                 
               Typical Capacity (mAh) 
               170 
             
             
                 
               Height (mm) 
               10.80 
             
             
                 
               Diameter (mm) 
               11.60 
             
             
                 
               Weight (g) 
               3.00 
             
             
                 
                 
             
           
        
       
     
   
   Throughout the specification the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features. Persons skilled in the relevant art may realize variations from the specific embodiments that will nonetheless fall within the scope of the invention.