Patent Publication Number: US-6655776-B2

Title: Media pack for combination image acquisition and printing device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electronic cameras and more specifically to the printing of images produced by such camera. 
     2. Description of the Related Art 
     Digital cameras, digital phones, PDAs and the like which obtain and display acquired images electronically are in widespread use. Digital images produced from these devices are typically stored in memory and these images can be shown on a display so that the user can determine which image should be stored for use in producing hard copy images. Typically, these images can be stored in a magnetic disk or a compact PCMCIA Flash RAM Card. Once stored, the image data is generally downloaded to a separate print apparatus for hard copy production. 
     More recently, attempts have been made to incorporate printing apparatus into the cameras themselves so that no separate printing apparatus is required. With such a combination camera/printing apparatus, images can be acquired and printed at any location, without waiting to perform a separate image download to other processing and print apparatus. 
     One example of this type of combination camera and printing apparatus is provided in U.S. Pat. No. 5,757,388 to Stephenson. This document shows an electronic imaging camera and an ink jet printing apparatus which can be interconnected for use either in combination or apart. In this device, the image acquisition apparatus is provided in one housing, and the printing apparatus is provided in a second separate housing. This device is thus essentially two separate devices with a means for coupling the two together. Another example camera/printing apparatus combination is provided by U.S. Pat. No. 6,149,256 to McIntyre. In this case, a single housing includes the image acquisition apparatus and a page wide print head. A separate housing is used to provide sheets of paper, ink, and a power supply for the printing apparatus. Although both of these documents describe combination camera and printing apparatus embodiments, neither is designed to optimize print quality while minimizing the size and cost of producing and operating the apparatus. 
     SUMMARY OF THE INVENTION 
     In one embodiment, the invention comprises a media pack for a combination image acquisition and ink jet printing apparatus. The media pack advantageously comprises a housing configured for insertion into the combination digital camera and ink jet printing apparatus, a plurality of sheets of ink receiving media contained within the housing, a plurality of ink reservoirs mounted to the housing, and a writeable and readable memory element attached to the housing. In one embodiment, the writeable and readable memory element is positioned on a top surface of the housing. In another embodiment, a media pack for a combination image acquisition and ink jet printing apparatus comprises a housing configured for insertion into the combination digital camera and ink jet printing apparatus, a plurality of sheets of ink receiving media contained within the housing, a plurality of ink reservoirs mounted to the housing, and a service station portion formed by the housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of a digital camera and ink jet printing apparatus in an integral housing in accordance with the present invention. 
     FIG. 2 is a cross sectional view of the printing apparatus assembly of FIG. 1 along the line  2 — 2  of FIG.  1 . 
     FIG. 3A is a cutaway side view of the camera/printing apparatus of FIGS. 1 and 2 with a removable media pack installed. 
     FIG. 3B is a perspective view of the camera/printing apparatus of FIGS. 1 and 2 with the camera housing cut away. 
     FIG. 4 is a perspective view of the removable media pack of FIG. 3 removed from the camera. 
     FIG. 5 is a top view of an ink jet printing apparatus carriage assembly with cam structures for media advance. 
     FIG. 6A is a top view of the assembly of FIG. 5 with the cam in a first position. 
     FIG. 6B is a top view of the assembly of FIG. 5 with the cam rotated to a second position. 
     FIG. 7A is a side view of a second embodiment of a cam structure for media advance. 
     FIG. 7B is a top view of the embodiment of FIG. 7A with the cam in a first position. 
     FIG. 7C is a top view of the embodiment of FIG. 7A with the cam rotated to a second position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the invention will now be described with reference to the accompanying Figures, wherein like numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the inventions herein described. 
     The invention is directed to an imaging acquisition device and a compact ink jet printing apparatus contained in an integral housing. The imaging acquisition device could be a digital camera of conventional design and can capture either still or motion images. Such cameras often have a flat panel color display that is used to frame and/or review captured images. 
     Turning now to FIG. 1, a housing  10  with an image acquisition device  12  and an ink jet printing apparatus  14  is shown. Images are captured by the image acquisition device  12  which typically includes an optical system and an image sensor such as a CCD. The device may be a camera, PDA, cell phone, or any device that receives and stores images. Digital image data, which may be in raster format, from image capture circuitry  16  is transferred to a scanning print head  18  for hard copy image production as will be described in additional detail below. The image capture circuitry  16  may additionally include a storage memory for storing digital images captured by the system. These stored images may be used to drive a display  20  in a well known manner. Display  20  can be for instance a LCD or organic polymer display system of conventional design. 
     The image capture electronics processes the data and formats it for immediate printing by organizing the data in scan lines according to the physical layout of the ink jet print head. This organization allows the image capture electronics to perform a majority of the processing functions and thereby allows straightforward reproduction of image data by print the ink jet print head with minimal additional processing, thereby reducing redundant hardware including additional memory, resulting in reduction of the cost of the device. 
     In advantageous embodiments of the invention, the print head  18  contained within the housing  10  is a scanning print head which is moveable in the direction of arrows  21  and  22  along a guide rod  24  over a sheet of ink receiving media  29 , typically paper. During the printing process, the media  29  is advanced in a first direction (out of the plane of FIG. 1) with a media advance drive member, while the scanning print head travels back and forth across the media  29  in a direction transverse to the first direction of media advance depositing swaths of ink droplets. In this manner, an image is formed by the ink jet printing apparatus. There are many advantages to the scanning print head over page wide non-moving ink jet head designs. Not only are smaller moving print heads less expensive and easier to replace, but they produce a higher print quality as well. This is because droplet deposition errors are randomized and spread throughout the image by the movement of the print head. With page wide print heads, droplet deposition errors tend to be systematic, occurring in bands within the image, and producing non correctable imperfections in print quality which are much more noticeable to the human eye than random errors. In one advantageous embodiment, the guide rod  24  on which the print head  18  is mounted also forms the media drive member. This is illustrated more fully in FIG.  2 . 
     FIG. 2 is a cross sectional view of the printing assembly  14  along lines  2 — 2  of FIG.  1 . As seen in this Figure, the ink jet print head  18  may be mounted to or incorporate a bushing  48  which slidably engages the guide rod  24 . The guide rod  24  is free to rotate within the bushing  48 . The bottom surface of the guide rod  24  contacts the top sheet  29  of a stack of media such that when the guide rod  24  is incrementally rotated, the top media sheet  29  is also advanced. The print head is rotationally supported in a manner similar to that of conventional ink jet printer, with an extension  37  that slides along a support surface  39  that is behind the print head. Thus, the rotatable guide rod  24 , disposed over the media stack, is actuated to advance one of the media sheets  50  past the ink jet print carriage  22  during the printing process. 
     To produce the transverse print head motion, the print head is coupled to a drive belt assembly  27 . Other print head moving systems may utilize a motor and screw drive instead of drive belt. Ink supply tubing  28  supplies ink from ink reservoirs outside the print head  18 . As in conventional ink jet print heads, the print head  18  has a jet plate  31  on its bottom surface containing nozzles for ink ejection. The jet plate is coupled to a flex circuit  33  which routes electrical signals to the jet plate for nozzle actuation. To produce a low profile head for small size, the flex circuit  33  is routed around to the front surface of the print head  1 . Electrical contacts on this portion of the flex circuit  33  connect to mating electrical contacts on a second flex circuit  35  which is connected via a trailing cable connection to driver and routing control logic and to the processing circuitry  16  of FIG. 1 so as to control ink ejection during the image printing process. A specific advantageous method and apparatus for producing the desired media and print head motion is described in more detail below with reference to FIGS. 5,  6 , and  7 . 
     In one embodiment, illustrated in FIGS. 3A and 3B, the media sheets are housed in a media pack that is user insertable into and user removable from the housing  10  containing the image acquisition and printing apparatus. The media may thus be incorporated into a second housing  52  separate from the first housing  10 , forming an inexpensive, disposable media pack for the camera/printing system. In some advantageous embodiments, the second housing  52  may be inserted into the first housing  10  from the rear. In one media pack embodiment, the media sheets rest on a spring loaded platen  54 . A biasing member  56  urges the platen  54  with the media sheets  50  against the guide rod/drive roller  24 . The second housing  52  may also include an ink reservoir  58  which couples to the ink supply tubing  28  when the media housing  52  is installed in the camera/printing apparatus housing  10 . 
     The relationship between the media pack and printing apparatus when the media pack housing  52  is installed in the housing  10  is such that print head travel is over the front portion of the media pack housing  52  and above the media sheets as they sit inside the housing  52 . This reduces the total size of the device as media sheets need not be advanced to a printer assembly which is spatially separated from the media source in order to initiate the print process. As will be explained further below, this arrangement also allows a print head service station area to be incorporated into the media pack. 
     FIG. 4 is a perspective view of the removable media pack illustrated in FIG.  3 . The housing  52  includes media  30 , which is exposed to contact from the guide rod/drive roller  24  when installed in the camera/printing apparatus. Also provided are ink outlets  60  for coupling to the ink supply tubing  28 . In one advantageous embodiment, the media pack includes a writable and readable memory element  62 , such as a FLASH memory. With this memory element  62 , not only can initial characteristics of the media pack be stored, such as ink or media type, or initial number of media sheets provided, but also, the information can be updated so that the user can be kept informed, for example, of how many media sheets are left or how many have been used. Also, if the media pack is removed from the camera &amp; later reinserted, the camera may automatically determine the number of sheets left. When sheets are used up or low, the camera knows this and may stop printing requests or notify user to replace with a new media pack. The memory element may incorporate a two pin serial bus which allows easy access by the image processing apparatus. Using this common serial bus technique, power may also be provided without use of additional interface pins. Such memory devices are commercially available from Dallas Semiconductors and others. 
     The memory element is advantageously placed on the top surface of the housing  52  and is connected to electrical contacts  64  for interfacing with the electronics in the camera/printing apparatus. Referring back to FIG. 3B, this placement allows the electrical contacts  64  to mate with contacts on a main printing apparatus circuit board (not shown) mounted to the shelf  39  in the camera housing  10 . This eliminates the need to provide an additional interface circuit board in the camera housing to interface with the memory element contacts  64 , thus minimizing the cost and size of the device. 
     In addition, the housing  52  may include a print head service station area  57  with an ink absorbent foam pad  59 . During printing, the print head can travel past the media edge and eject droplets (or “spit”) over the foam pad  59  to clear nozzles. This area may also include other components (not shown) such as a print head wiper and a rubber seal for sealing the ink jet print head when not in use, as are commonly provided on larger scale ink jet printers. When idle, the print head would reside over this area of the media pack above the foam pad and sealed, if a seal is provided. With this embodiment, mess from waste ink and print head servicing is quickly disposed of with each replacement of the media pack. 
     Turning now to FIGS. 5,  6 A, and  6 B, an advantageous print head and media advance mechanism is described. The embodiments shown in these figures are especially advantageous in this application because only a single motor is required to advance both the print head and the media. This allows for both space and cost savings in a combined camera/printing apparatus. 
     Referring now to FIG. 5, a bidirectional printing apparatus (wherein ink is deposited when the print head moves in both directions across the media) is illustrated. As described above, the ink jet print head  18  is slidably mounted on the guide rod and paper drive roller  24  to enable motion of the ink jet print head along the paper drive roller  24  and to define a linear path, as shown by the bi-directional arrow in FIG. 5, along which the ink jet print head  22  moves. A motor  26  and drive belt mechanism  27  (or screw drive, for example) are used to drive the ink jet print head  18  along the paper drive roller  24 . 
     The paper drive roller  24  is attached at each end to a cam  30   a,    30   b.  The cams  30  are generally circular disks with a plurality of protrusions  32   a,    32   b  on their outer circumference. Each protrusion  32  is configured  30  such that a driving surface  38   a,    38   b  is created at an angle relative to the inner face  40  of the protrusion  32 . Alternately, other embodiments of protrusions  32  can be used that provide driving surfaces on the cams  30 . 
     The print head  18  includes extended actuators  42   a,    42   b  protruding from the sides of the print head  18 . A protruding end  46   a,    46   b  of the actuator may be shaped at an angle or it may be rounded so that each protruding end  46  can engage with the driving surface  38  of one of the protrusions  32  on the cam  30 . 
     As the print head  18  reaches one end of travel along the paper drive roller  24 , the drive motor  26  pushes the protruding end  46   a  of the actuator against the driving surface  38   a  of a protrusion on the end of cam  30   a,  causing the cam  30   a  (and the attached drive roller) to rotate from a first position as shown in FIG. 6A to a second position as shown in FIG.  6 B. The rotation of the cam  30  rotates the paper drive roller  24 , thereby advancing the media sheet  50  an incremental amount. 
     When the print head  18  travels back to the other side of the roller  24 , the actuator  42   b  on the other side of the print head contacts the driving surface  38   b  on the other cam  30   b,  causing a similar rotation of the paper drive roller. The protrusions on the cam  30   a  are rotationally out of phase with the protrusions on the cam  30   b,  such that the rotation caused at one end positions the protrusions on the cam at the other end into the proper position to be engaged with the other actuator. 
     Accordingly, a printed image is formed on the media sheet  50  by advancing the media sheet in incremental amounts using paper drive roller  24  each time the print head  18  reaches an end of travel along the paper roller  24 . 
     Another embodiment suitable for unidirectional printing (wherein ink is deposited during only one direction of print head travel) is shown in FIGS. 7A,  7 B, and  7 C. In this case, only one cam  30  is required. In this embodiment, the protrusion  42  may comprise an articulating arm with a downwardly projecting tip  43  as shown in the side view of FIG.  7 A. As the print head  18  moves toward the cam  30 , the tip  43  moves along the driving surface  38  of a protrusion  45  advancing the cam  30 . During this process, the tip  43  moves behind the adjacent protrusion  47  and in the gap  51  between the protrusion  45  and the protrusion  47 , while the horizontally extending portion  49  of the actuator passes over the top of the adjacent protrusion  47  as shown in FIGS. 7B and 7C. The arm is hinged such that on return motion, the tip  43  can rise up and over the rear surface of the adjacent protrusion  47 , releasing the cam  30  as the print head moves away toward the other side of the roller  24 . When the print head returns on the next pass, the tip  43  is positioned to engage the front of the adjacent protrusion  47 , again advancing the cam  30  and the roller  24 . In this way, the media advance is accomplished in a single sided operation. 
     The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the invention should therefore be construed in accordance with the appended claims and any equivalents thereof.