Abstract:
A camera is provided having a first image capture portion connected to a base by means of a pivot assembly. An electronic imaging sensor is located in the image capture portion and signals from the camera are conveyed by electrical contacts disposed about the base. In order to facilitate electrical communication between the imaging sensor and the electrical contacts over the full pivoting range, an integrated image processing circuit is mounted to a flexible PCB that interconnects the image capture portion with the contacts. The flexible PCB is sufficiently slack to accommodate pivoting of the image capture portion relative to the base.

Description:
[0001]     This is Continuation application of Ser. No. 10/636,234 filed on Aug. 8, 2003 
     
    
     FIELD OF THE INVENTION  
       [0002]     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 camera module for the compact printer system.  
         [0003]     Reference may be had to co-pending applications claiming priority from Australian Provisional Patent Application number PQ0560 dated May 25, 1999. The co-pending applications describe related modules and methods for implementing the compact printer system. The co-pending patent/applications are as follows:  
                                   USSN   Title                   09/575,182   Compact Color Printer Module       6,712,452   Modular Compact Printer System       6,416,160   Nozzle Capping Mechanism       6,238,043   Ink Cartridge for Compact Printer System       09/575,119   Controller for Printer Module       09/575,157   Image Processor for Camera Module       6,554,459   Memory Module for Compact Printer System       09/575,134   Effects Module for Compact Printer System       09/575,121   Effects Processor for Effects Module       09/575,137   Timer Module for Compact Printer System       6,804,026   Color Conversion Method for Compact Printer System       09/575,120   Method and Apparatus of Dithering       09/575,122   Method and Apparatus of Image Conversion                  
 
       BACKGROUND OF THE INVENTION  
       [0004]     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.  
         [0005]     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.  
         [0006]     A compact printhead has been described in co-pending U.S. patent applications filed simultaneously to the present application and hereby incorporated by cross reference:  
                                   USSN   Title                   09/575,152   Fluidic seal for an ink jet nozzle assembly       6,428,133   Ink jet printhead having a moving nozzle with an           externally arranged actuator       6,526,658   Method of manufacture of an ink jet printhead having           a moving nozzle with an externally arranged actuator       09/575,176   Ink jet printhead nozzle array       6,390,591   Nozzle guard for an ink jet printhead                  
 
         [0007]     Although digital cameras are known, they require connection to a personal computer before a hardcopy image can be obtained. Generally, it is necessary to upload images from the camera to the personal computer and then print the images on a desktop printer using a proprietary software package that makes the necessary translation between the image format taken by the camera and the format required by the printer. A camera that is able to link directly to a compact printer would be more desirable.  
       SUMMARY OF THE INVENTION  
       [0008]     In one form, the invention resides in a camera module for a compact printer system comprising: 
        a body;     a flexible printed circuit board within said body, said flexible printed circuit board containing an image sensor that captures an image of a scene and an image processor that processes said image into a form suitable for transferring directly to a printer module;     a connector, at an end of said body, for connecting said camera module to said printer module, said connector incorporating connection to a bus providing power and data between said camera module and said printer module.        
 
         [0012]     Further features of the invention will be evident from the following description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     In order to assist with describing preferred embodiments of the invention, reference will be made to the following figures in which:  
         [0014]      FIG. 1  is a printer module;  
         [0015]      FIG. 2  is a camera module;  
         [0016]      FIG. 3  is a memory module;  
         [0017]      FIG. 4  is a communication module;  
         [0018]      FIG. 5  is a flash module;  
         [0019]      FIG. 6  is a timer module;  
         [0020]      FIG. 7  is a laser module;  
         [0021]      FIG. 8  is an effects module;  
         [0022]      FIG. 9  is a characters module;  
         [0023]      FIG. 10  is an adaptor module;  
         [0024]      FIG. 11  is a pen module;  
         [0025]      FIG. 12  is a dispenser module;  
         [0026]      FIG. 13  is a first compact printer configuration;  
         [0027]      FIG. 14  is a second compact printer configuration;  
         [0028]      FIG. 15  is a third compact printer configuration;  
         [0029]      FIG. 16  is a fourth compact printer configuration;  
         [0030]      FIG. 17  is a perspective view of the camera module of  FIG. 2 ;  
         [0031]      FIG. 18  is a perspective view of the camera module in a folded position;  
         [0032]      FIG. 19  is an exploded view of the camera of the camera module;  
         [0033]      FIG. 20  is an exploded view of the base of the camera module;  
         [0034]      FIG. 21  is a partly exploded view of the camera module;  
         [0035]      FIG. 22  is a cut away side view of the camera module of  FIG. 17 ; and  
         [0036]      FIG. 23  is a block schematic diagram of an image processor chip. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]     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.  
         [0038]     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.  
         [0039]     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.  
         [0040]     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.  
         [0041]     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.  
         [0042]     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.        
 
         [0046]     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 .  
         [0047]      FIG. 1  shows a printer module that incorporates a compact printhead described in co-pending U.S. 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 □m in diameter, and spaced 15.875 □m 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.  
         [0048]     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 .  
         [0049]      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 portion  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 processed and 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.  
         [0050]      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.  
         [0051]     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.  
         [0052]     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 .  
         [0053]     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.  
         [0054]      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.  
         [0055]     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.  
         [0056]     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.  
         [0057]      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 .  
         [0058]     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.  
         [0059]     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.  
         [0060]      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.  
         [0061]     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.  
         [0062]     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.  
         [0063]     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 .  
         [0064]     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.  
         [0065]     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.  
         [0066]     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.  
         [0067]      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.  
         [0068]     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.  
         [0069]     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.  
         [0070]     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 .  
         [0071]     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.  
         [0072]     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.  
         [0073]     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.  
         [0074]     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.  
         [0075]     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.  
         [0076]     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.  
         [0077]     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).  
         [0078]     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*.  
         [0079]     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).  
         [0080]     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.  
         [0081]     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.  
         [0082]     The Camera Module  20  provides a point-and-shoot camera component to the compact printer system as a means of capturing images. The Camera Module  20  is a standard module containing an image sensor and specialized image processing chip. Captured images are transferred to the Printer Module  10  for subsequent printing, manipulation, or storage. The Camera Module  20  may also contain a self-timer mode similar to that found on known cameras.  
         [0083]      FIG. 17  shows a magnified perspective view of the Camera Module  20 , as previously described with reference to  FIG. 2 . As shown by  FIG. 18 , there is a swivel connection between the camera portion  24  and the base portion  28  that allows the camera  24  to be aligned with the base  28  for ease of carriage. Also visible in  FIG. 18  is the self-timer switch  29 .  
         [0084]      FIG. 19  is an exploded view of the camera  24 . The core of the camera is a CMOS imaging sensor  241  mounted on a flexible printed circuit board (PCB)  242 . Also formed on the PCB  242  is an image processing chip  243  which may be an application specific integrated circuit. The lens  23  focuses the view onto the image sensor  241 . The viewfinder  25  allows the user to select the image to be captured by looking through eyepiece  251 .  
         [0085]     The lens  23 , viewfinder  25  and image sensor  241  are held in chassis molding  213  formed as a pair of half moldings. A front molding  214  is glued to the chassis molding  213  and protects the lens  23  and viewfinder  25 . The lens cap  26  rotates on pivot  261 . The cap is spring loaded by spring  262 .  
         [0086]     The camera  24  is mechanically connected to base  28  by pivot assembly  281 . The pivot assembly  281  consists of a cam molding  282 . A pin  283  fits in hole  284  to hold the upper end of the cam molding  282  in the chasses molding  213 . The lower end of the cam molding is held in the base  28  in the manner described below.  
         [0087]     The flex PCB  242  threads through the cam molding and terminates in contacts  221  that connect to the Serial Bus at the female connector  22 . A contact  271  forms part of the take button  27 . An LED  272  in the take button  27  gives a visual indication of a ten second countdown that applies when the self-timer switch  29  activates the self-timer. The components of the camera  24  are contained within a metal case  211 .  
         [0088]     The base  28  includes an upper molding  285  with slot  286  that receives pin  287 . The pin  287  captures the lower end of the pivot assembly  281 . The pin  287  is biased by springs  288  towards the bottom of the slot  286 . The camera  24  is lifted away from the base  28  to allow it to pivot between the positions shown in  FIG. 17  and  FIG. 18 .  
         [0089]     The self-timer switch  29  fits in slot  291  and activates the switch by sliding small contact  292  against large contact  293 . The actual switch is formed in two parts  294  and  295 .  
         [0090]     The base  28  also includes a lower molding  289  that carries contact strips  222 . The contacts  221  on the end of the flex PCB  242  mate with the contact strips  222  to make the contact to the Serial Bus. A flange  273  supports the flex PCB  242  in the vicinity of the take button contact  271 .  
         [0091]     The components of the base  28  are contained within a metal extrusion  212 .  
         [0092]     The manner in which the components fit together is made clear in  FIG. 21  which is a partly exploded view of the camera module  20 , and in  FIG. 22  that is a cut-away view of the camera module  20 . Looking particularly at  FIG. 22 , the path of the flex PCB  242  can be clearly seen.  
         [0093]     The Camera Module  20  connects to a compact printer configuration via the female connector  22  which joins the camera module to the Serial Bus via contacts  222 . Power is provided from the Printer module  10  via the Serial Bus.  
         [0094]     To capture an image, a user simply presses the Take button  27 . The viewfinder  25  allows the user to frame the image before pressing the Take button.  
         [0095]     When the Take button  27  is pressed, the image is captured through the lens  23  and transferred to the Printer Module  10 . If the Take button is pressed again, a new image will be captured and transferred to the Printer Module. The image is always transferred to the Printer module once the Take button is pressed. Although the image remains in the Camera Module, there is no physical method of transferring the image from the Camera Module again. The image must be saved from the Printer Module instead (to, for example, the Memory Module  30 ). The only way of directly accessing the captured image is via a computer interface using the communication module  40 .  
         [0096]     The self-timer switch  29  set to off/on disables and enables a ten second delay between the pressing of the Take button and the capturing of the image. The LED inside the Take button provides a visual feedback during the countdown. The LED flashes once per second, and then stays on for the final two seconds of the countdown. The self-timing functionality is therefore identical to that of a conventional camera.  
         [0097]     If there is an active Flash Module  50  present in the compact printer configuration, then the Flash will be activated depending on the Flash Module&#39;s flash mode. If the Flash Module has been turned off, then the flash will not fire. If the Flash Module is set to auto, then the flash fires as necessary (light detection carried out by the Camera Module).  
         [0098]     As mentioned above, an application specific integrated circuit (ASIC) configured as an image processor  243  processes images captured by the image sensor  241 . The elements of the image processor  243  are shown in  FIG. 23 . The elements of the image processor ASIC are described in detail in a co-pending application titled Image Processor for Printer Module. The image processor  243  includes an image capture unit  231  that receives an image from the image sensor  241 . The image is processed by an image histogram unit  232  and image enhancement unit  233 . The captured image is a Bayer color filter array RGB image and it is transformed to an 850×534 contone L*a*b* output image.  
         [0099]     The processed image is stored in ImageRAM  234 . In normal operation the image is placed on the Serial Bus through the Serial Bus interface  235  and transferred to the printer module  10  for printing. A low speed CPU  236  with associated program memory  237  and variable memory  238  take care of housekeeping and administration tasks.  
         [0100]     A CPU Memory Decoder  239  is a simple decoder for satisfying CPU data accesses. The Decoder translates data addresses into internal register accesses over the internal low speed bus  240 , and therefore allows for memory mapped I/O of image processor registers. The bus  240  includes address lines  240   a  and data or control lines  240   b.    
         [0101]     A parallel interface  241  connects the image processor to individual static electrical signals, such as LCD segments  242  and buttons  243  (eg. self timer). The CPU  236  is able to control each of these connections as memory-mapped I/O via the low-speed bus  240 .  
         [0102]     A standard JTAG (Joint Test Action Group) Interface  244  may be included in the image processor for testing purposes. Due to the complexity of the chip, a variety of testing techniques are required, including BIST (Built In Self Test) and functional block isolation.  
         [0103]     The image processor  236  may also include a clock phase-locked loop  245  that provides timing signals to the controller. The clock  245  draws a base signal from crystal oscillator  246 . Some CPU include a clock so the clock  245  and crystal  246  may not be required.  
         [0104]     The Camera Module  20  can be instructed to take a photo either by a computer (via the Communication Module  40 ) or by another module. However in both cases, the self-timer switch is ignored and the captured image is not transferred to the Printer Module. Instead, the image is simply captured and stored locally in the Camera Module in ImageRam  234 . The Camera Module can then be instructed in a subsequent command to transfer its image to a specified module or simply to return it to the caller.  
         [0105]     The combination of the camera module  20  with the printer module  10  constitutes a minimum compact printer system that allows an image to be captured and printed directly.  
         [0106]     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.