Abstract:
A method of assembling a gear arrangement for a capper of an inkjet printer, the method comprising the steps of: mounting a first gear assembly to the printer so as to cooperate with a motor gear for driving rotation of the first gear assembly, the first gear assembly having a code feature; and mounting a second gear assembly the printer so as to cooperate with the first gear assembly to be rotatable therewith, the second gear assembly, in use, cooperating with a capper for capping a printhead so that the rotation of the second gear assembly moves the capper out of and into its capping position, wherein in the step of mounting the second gear assembly the code feature of the first gear assembly is arranged to cooperate with a holding feature of a mounting arrangement used to mount the second gear assembly to the printer, the code feature being configured so that the cooperation with the holding feature maintains the first gear assembly at a predetermined position during the mounting of the second gear assembly.

Description:
FIELD OF THE INVENTION 
   The present invention relates to method of assembly a capping mechanism of an inkjet printer which is configured to provide accurate capping of an inkjet printhead of the printer. 
   CO-PENDING APPLICATIONS 
   The following applications have been filed by the Applicant simultaneously with the present application: 
   
     
       
             
             
             
             
             
           
         
             
                 
             
           
           
             
               11/293,800 
               11/293,802 
               11/293,801 
               11/293,808 
               11/293,809 
             
             
               11/293,832 
               11/293,838 
               11/293,825 
               11/293,841 
               11/293,799 
             
             
               11/293,796 
               11/293,797 
               11/293,798 
               11/293,804 
               11/293,840 
             
             
               11/293,803 
               11/293,833 
               11/293,834 
               11/293,835 
               11/293,836 
             
             
               11/293,837 
               11/293,792 
               11/293,794 
               11/293,839 
               11/293,826 
             
             
               11/293,829 
               11/293,830 
               11/293,827 
               11/293,828 
               7,270,494 
             
             
               11/293,823 
               11/293,824 
               11/293,831 
               11/293,815 
               11/293,818 
             
             
               11/293,817 
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               11/293,812 
               7,357,496 
               11/293,814 
               11/293,793 
               11/293,842 
             
             
               11/293,811 
               11/293,807 
               11/293,806 
               11/293,805 
               11/293,810 
             
             
                 
             
           
        
       
     
   
   The disclosures of these co-pending applications are incorporated herein by reference. 
   CROSS REFERENCES TO RELATED APPLICATIONS 
   Various methods, systems and apparatus relating to the present invention are disclosed in the following U.S Patents/Patent Applications filed by the applicant or assignee of the present invention: 
   
     
       
             
             
             
             
             
             
           
         
             
                 
             
           
           
             
               6,750,901 
               6,476,863 
               6,788,336 
               7,249,108 
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               6,331,946 
             
             
               6,246,970 
               6,442,525 
               7,346,586 
               09/505,951 
               6,374,354 
               7,246,098 
             
             
               6,816,968 
               6,757,832 
               6,334,190 
               6,745,331 
               7,249,109 
               7,197,642 
             
             
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               10/636,263 
               10/636,283 
               10/866,608 
               7,210,038 
               10/902,883 
             
             
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               7,364,256 
               7,258,417 
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               7,334,864 
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               7,284,819 
             
             
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               7,270,393 
               6,984,017 
               7,347,526 
             
             
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               6,550,895 
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               7,152,962 
             
             
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               10/815,628 
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               09/575,197 
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               6,825,945 
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               6,813,039 
               6,987,506 
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               6,980,318 
             
             
               6,816,274 
               7,102,772 
               7,350,236 
               6,681,045 
               6,728,000 
               7,173,722 
             
             
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               6,789,191 
             
             
               6,644,642 
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               6,669,385 
               6,549,935 
               6,987,573 
             
             
               6,727,996 
               6,591,884 
               6,439,706 
               6,760,119 
               7,295,332 
               6,290,349 
             
             
               6,428,155 
               6,785,016 
               6,870,966 
               6,822,639 
               6,737,591 
               7,055,739 
             
             
               7,233,320 
               6,830,196 
               6,832,717 
               6,957,768 
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               7,171,323 
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               6,795,215 
               7,070,098 
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               6,805,419 
               6,859,289 
             
             
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               7,198,352 
               7,364,264 
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               7,201,470 
               7,121,655 
               7,293,861 
             
             
               7,232,208 
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               7,344,232 
               7,083,272 
               11/014,764 
               11/014,763 
             
             
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               7,303,252 
             
             
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               7,390,080 
             
             
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   The disclosures of these applications and patents are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   In inkjet printers having printheads of ink ejection nozzles for ejecting ink onto a surface of print media, such as paper, it is important to cap the nozzles from the atmosphere when the printhead is not in use. This is because, when exposed to the atmosphere ink within the nozzles may dry. This dry ink may clog the nozzles rendering the printhead inefficient and at worst unusable. A capping mechanism is conventionally used for this purpose. It is important that the capping mechanism normally caps the printhead. Preferably, this normally capped position is maintained without requiring power. This ensures that minimal power is consumed for the capping/uncapping operation and that the printhead will only be uncapped upon performance of printing and not in the event of a power cut to the capping mechanism. However, such a quality assurance feature of the capping mechanism can be destroyed if, during the manufacture assembly of the capping mechanism, the correct capping timing position is not maintained. 
   SUMMARY OF THE INVENTION 
   The present invention suitably codes the gearing arrangement for actuating the capper, thereby maintaining the correct capping timing position of the capper during and after assembly. 
   In a first aspect the present invention provides a method of assembling a gear arrangement for a capper of an inkjet printer, the method comprising the steps of:
         mounting a first gear assembly to the printer so as to cooperate with a motor gear for driving rotation of the first gear assembly, the first gear assembly having a code feature; and   mounting a second gear assembly the printer so as to cooperate with the first gear assembly to be rotatable therewith, the second gear assembly, in use, cooperating with a capper for capping a printhead so that the rotation of the second gear assembly moves the capper out of and into its capping position,   wherein in the step of mounting the second gear assembly the code feature of the first gear assembly is arranged to cooperate with a holding feature of a mounting arrangement used to mount the second gear assembly to the printer, the code feature being configured so that the cooperation with the holding feature maintains the first gear assembly at a predetermined position during the mounting of the second gear assembly.       

   Optionally, the step of mounting the first gear assembly comprises mounting a common shaft connecting first and second gears of the first gear assembly to the body so that the first gear meshes with the motor gear and the second gear meshes with the second gear assembly. 
   Optionally, the first gear incorporates the code feature. 
   Optionally, the step of mounting the second gear assembly comprises mounting a pin of a third gear of the second gear assembly to the body so that the third gear meshes with the second gear of the first gear assembly. 
   Optionally, the third gear has an eccentricity feature configured to cooperate with an actuator feature of the capper, the cooperation causing the movement of the capper out of and into its capping position. 
   Optionally, the predetermined position of the first gear assembly is configured to position the eccentricity feature of the third gear of the second gear assembly in a predetermined cooperation with the actuator feature of the capper. 
   Optionally, the eccentricity feature is configured to go into and out of cooperation with the actuator feature of the capper based on the rotated position of the third gear in relation to the capper. 
   Optionally, the predetermined cooperation is configured to maintain the capper in its capping position. 
   In a further aspect there is provided a method wherein:
         wherein the step of mounting the first gear assembly comprises mounting the common shaft connecting the first gear and two second gears to the body so that each of the second gears mesh with the second gear assembly; and   the step of mounting the second gear assembly comprises mounting a pin of two third gears to the body so that each of the third gears mesh with a respective one of the second gears of the first gear assembly.       

   Optionally, each of the third gears has an eccentricity feature configured to cooperate with a corresponding actuator feature of the capper, the cooperation causing the movement of the capper out of and into its capping position. 
   Optionally, the predetermined position of the first gear assembly is configured to position the eccentricity features of the third gears of the second gear assembly in a predetermined cooperation with the actuator features of the capper. 
   Optionally, each eccentricity feature is configured to go into and out of cooperation with the respective actuator feature of the capper based on the rotated position of the third gears in relation to the capper. 
   Optionally, the predetermined cooperation is configured to maintain the capper in its capping position. 
   In a second aspect the present invention provides an inkjet printer comprising:
         a media supply; and   a gripless driven roller and an idler roller arranged, in use, to take-up the media therebetween from the media supply and feed it past a printhead having a plurality of ink ejection nozzles arranged to print on the media as it is fed past the nozzles, the driven roller being rotatably driven so as to impart translational motion to the media upon contact with the media,   wherein a contact surface of the gripless driven roller which contacts the media is substantially plain.       

   Optionally, the driven roller is a plain shaft roller. 
   Optionally, the contact surface of the driven roller is incorporated in at least one tubular sleeve arranged about an elongate shaft. 
   Optionally, the idler roller is supported by a body of the printer so as to be moveable away from and toward the driven roller whilst maintaining a minimum gap between the driven and idler rollers, the idler roller being arranged to rotate due to the translational motion imparted to the media. 
   Optionally, the minimum gap between the driven and idler rollers is less than a thickness of the media, the movement of the idler roller being configured to allow the media to pass between, and contact, the contact surfaces of the driven and idler rollers. 
   Optionally, the minimum gap is about 200 microns and a thickness of the media is at least about 250 microns. 
   Optionally, the media is photo paper. 
   Optionally, the photo paper is 4 by 6 inch photo paper. 
   Optionally, the driven and idler rollers are configured to transport the 4 by 6 inch photo paper, and the pagewidth printhead is configured to print across a 4 by 6 inch pagewidth. 
   Optionally, the photo paper has a pagewidth of about 100 millimeters. 
   Optionally, the driven and idler rollers are configured to transport the 100 millimeter wide photo paper, and the pagewidth printhead is configured to print across the 100 millimeter pagewidth. 
   Optionally, the idler roller is biased towards the driven roller by a spring assembly mounted to the body, the spring constant of the spring assembly being configured so that the take-up of the media causes the movement of the idler roller away from the driven roller. 
   Optionally, the driven roller is rotatably driven by a motor mounted to a body of the printer. 
   Optionally, the driven roller is operationally connected to the motor via a pulley assembly. 
   Optionally, the pulley assembly incorporates a first pulley wheel arranged about one longitudinal end of the driven roller, a second pulley wheel arranged about a shaft of the motor and a belt arranged about the first and second pulley wheels. 
   Optionally, the belt is a smooth belt. 
   Optionally, the pulley assembly further incorporates a tensioner for tensioning the belt about the first and second pulley wheels. 
   Optionally, the printhead is incorporated in a printing cartridge which is removably engageable with the printer. 
   Optionally, the printhead is pagewidth printhead, a pagewidth being about 100 mm. 
   Optionally, the media supply is incorporated in a media cartridge which is removably engageable with the printer. 
   In a third aspect the present invention provides a printer comprising:
         at least one elongate roller arranged, in use, to rotate so as to transport print media within the printer;   a support frame for supporting the roller at the longitudinal first and second ends of the roller so as to allow the rotation of the roller; and   fixing means for fixing the roller to the support frame at the first end of the roller, the fixing means comprising:
           a bearing into which the first end of the roller is positioned for allowing the rotation of the roller; and   engagement means arranged to slidably engage with the support frame so as to fix the roller thereto, the bearing being configured to allow pivotal movement of the elongate roller about the second end of the roller during the sliding engagement of the engagement means and support frame.   
               

   Optionally, the support frame has a slot through which the first end of the roller is able to pass so as to engage with the bearing of the fixing means, the slot being configured to allow movement of the first end during the sliding engagement of the engagement means and support frame. 
   Optionally, the movement of the first end during the sliding engagement moves the roller from being at an angle off normal to the transport path of the print media to being normal to the transport path; and the bearing is configured to accommodate the angular movement of the roller. 
   Optionally the bearing is configured to only contact the first end of the roller about a line around the circumference of the roller throughout the angular movement of the roller. 
   Optionally, a cross-section of the bearing contact face is triangular. 
   Optionally, the engagement means slidably engages with the support frame by sliding parallel to the transport path. 
   Optionally, the fixing means incorporates a plate having the bearing positioned in a hole therethrough, and the engagement means incorporates at least one tab provided on the plate, the tab being configured to slidably engage with a slot of the support frame. 
   In a further aspect there is provided a printer further comprising second fixing means for fixing the roller to the support frame at the second end of the roller, the second fixing means comprising:
         a second bearing into which the second end of the roller is positioned for allowing the rotation of the roller, the second bearing being configured to allow the pivotal movement of the elongate roller about the second end during the sliding engagement of the engagement means and support frame.       

   Optionally, the second bearing is configured to accommodate the angular movement of the roller during the sliding engagement of the engagement means and support frame. 
   Optionally, the second bearing is configured to only contact the second end of the roller about a line around the circumference of the roller throughout the angular movement of the roller. 
   Optionally, a cross-section of the second bearing contact face is triangular. 
   Optionally, the second fixing means incorporates a plate having the second bearing positioned in a hole therethrough and at least one tab provided on the plate configured to engage with a slot of the support frame. 
   In a further aspect there is provided a printer comprising a plurality of elongate rollers for transporting the print media,
         wherein the fixing means is arranged to fix each of the rollers to the support frame at the first end of the rollers, the fixing means comprising a plurality of the bearings with the first end of each roller being positioned in a corresponding bearing.       

   Optionally, the bearing of the fixing means for one of the rollers is arranged to be movable with respect to the fixing means so that said roller is allowed to move with respect to the transport path; and
         the fixing means comprises a spring for controlling the movement of said bearing.       

   Optionally, the fixing means incorporates a plate and a hole assembly arranged on the plate in which said roller is supported, the hole assembly being movable with respect to the plate; said bearing is arranged on said roller; and the spring is arranged on the plate to act against the hole assembly. 
   In a further aspect there is provided a printer comprising a plurality of elongate rollers for transporting the print media,
         wherein the first and second fixing means are arranged to fix each of the rollers to the support frame at the respective first and second ends of the rollers, the first and second fixing means comprising a plurality of the first and second bearings with the first and second ends of each roller being positioned in a corresponding respective bearing.       

   Optionally, the first and second bearings for one of the rollers are arranged to be movable with respect to the respective first and second fixing means so that said roller is allowed to move with respect to the transport path; and the first and second fixing means comprise a spring for controlling the movement of said first and second bearings. 
   Optionally, the first and second fixing means each incorporate a plate and a hole assembly arranged on the plate in which said roller is supported, the hole assembly being movable with respect to the plate; said first and second bearings are arranged on said roller; and each spring is arranged on the respective plate to act against the respective hole assembly. 
   Optionally, the plurality of rollers are arranged, in use, to transport the print media past a pagewidth printhead, the printhead being incorporated in a printing cartridge which is removably engageable with the printer. 
   Optionally, the print media is supplied to the plurality of rollers from a media cartridge which is removably engageable with the printer. 
   In a fourth aspect the present invention provides a method of assembling a print media transport arrangement of a printer, the method comprising the steps of:
         providing a support frame for at least one elongate roller;   positioning the roller so as to be supported at its longitudinal first and second ends by the support frame;   positioning a bearing of a fixing plate about the first end of the roller, the bearing being configured to allow rotation of the roller, the rotation, in use, providing transport of print media within the printer; and   slidably engaging the fixing plate with the support frame so as to fix the roller thereto,   wherein, during the sliding engagement, the elongate roller pivots about the second end due to the configuration of the bearing.       

   Optionally, in the step of positioning the roller, the first end of the roller is passed through a slot of the support frame, the slot being configured to allow movement of the first end during the engagement step. 
   Optionally, in the engagement step, the movement of the first end during the sliding engagement moves the roller from being at an angle off normal to the transport path of the print media to being normal to the transport path, the bearing being configured to accommodate the angular movement of the roller. 
   Optionally, the bearing is configured to only contact the first end of the roller about a line around the circumference of the roller throughout the angular movement of the roller in the engagement step. 
   Optionally, in the engagement step, the fixing plate is slid parallel to the transport path so as to slidably engage with the support frame. 
   Optionally, the fixing plate incorporates at least one tab configured to slidably engage with a slot of the support frame in the engagement step. 
   Optionally, in the step of positioning the roller so as to be supported at its longitudinal first and second ends by the support frame, the second end of the roller is positioned in a second bearing of a second fixing plate for fixing the second end of the roller to the support frame, the second bearing being configured to allow the rotation of the roller; and in the step of engaging the first fixing plate, the elongate roller pivots about the second end due to the configuration of both the first and second bearings. 
   Optionally, in the step of engaging the first fixing plate, the second bearing is configured to accommodate the angular movement of the roller. 
   Optionally, the second bearing is configured to only contact the second end of the roller about a line around the circumference of the roller throughout the angular movement of the roller in the step of engaging the first fixing plate. 
   Optionally, the step of positioning the roller comprises positioning a plurality of elongate rollers so as to be supported at their longitudinal first and second ends by the support frame; the step of positioning the bearing comprises positioning a plurality of bearings about the first end of each respective roller, each bearing being configured to allow rotation of the respective roller about the first end thereof; and in the engagement step, the configuration of each of the bearings allows the pivoting of the respective elongate roller about the second end thereof. 
   Optionally, the step of positioning the roller comprises positioning a plurality of elongate rollers so as to be supported at their longitudinal first ends by the support frame and positioned at their longitudinal second ends in a respective one of a plurality of second bearings of the second fixing plate, each second bearing being configured to allow rotation of the respective roller about the second end thereof; the step of positioning the first bearing of the first fixing plate comprises positioning a plurality of first bearings about the first end of each respective roller, each first bearing being configured to allow rotation of the respective roller about the first end thereof; and in the step of engaging the first fixing plate, the configuration of each of the bearings allows the pivoting of the respective elongate roller about the second end thereof. 
   In a fifth aspect the present invention provides an inkjet printer comprising:
         an elongate shaft arranged, in use, to rotate so as to move a capper for capping a pagewidth printhead out of and into its capping position;   a support frame for supporting the shaft at the longitudinal first and second ends of the shaft so as to allow the rotation of the shaft; and   fixing means for fixing the shaft to the support frame at the first end of the shaft, the fixing means comprising:
           a bearing into which the first end of the shaft is positioned for allowing the rotation of the shaft; and   engagement means arranged to slidably engage with the support frame so as to fix the shaft thereto, the bearing being configured to allow pivotal movement of the elongate shaft about the second end of the shaft during the sliding engagement of engagement means and support frame.   
               

   Optionally, the support frame has a slot through which the first end of the shaft is able to pass so as to engage with the bearing of the fixing means, the slot being configured to allow movement of the first end during the sliding engagement of the engagement means and support frame. 
   In a further aspect there is provided an inkjet printer wherein:
         the movement of the first end during the sliding engagement moves the shaft from being at an angle off parallel to the capping position to being parallel to the capping position; and   the bearing is configured to accommodate the angular movement of the shaft.       

   Optionally, the bearing is configured to only contact the first end of the shaft about a line around the circumference of the shaft throughout the angular movement of the shaft. 
   Optionally, a cross-section of the bearing contact face is triangular. 
   Optionally, the engagement means slidably engages with the support frame by sliding normal to the capping position. 
   Optionally, the fixing means incorporates a plate having the bearing positioned in a hole therethrough, and the engagement means incorporates at least one tab provided on the plate, the tab being configured to slidably engage with a slot of the support frame. 
   In a further aspect there is provided an inkjet printer, further comprising second fixing means for fixing the shaft to the support frame at the second end of the shaft, the second fixing means comprising:
         a second bearing into which the second end of the shaft is positioned for allowing the rotation of the shaft, the second bearing being configured to allow the pivotal movement of the elongate shaft about the second end during the sliding engagement of the engagement means and support frame.       

   Optionally, the second bearing is configured to accommodate the angular movement of the shaft during the sliding engagement of the engagement means and support frame. 
   Optionally, the second bearing is configured to only contact the second end of the shaft about a line around the circumference of the shaft throughout the angular movement of the shaft. 
   Optionally, a cross-section of the second bearing contact face is triangular. 
   Optionally, the second fixing means incorporates a plate having the second bearing positioned in a hole therethrough and at least one tab provided on the plate configured to engage with a slot of the support frame. 
   Optionally, the second fixing plate incorporates a seat for housing a motor for driving the rotation of the shaft. 
   Optionally, a gear is arranged on the second end of the shaft, the seat of the second fixing plate being configured to arranged a motor gear of the motor in mesh with the shaft gear. 
   Optionally, the motor gear is a worm gear arranged on a shaft of the motor, the seat of the second fixing plate being configured so that the motor may be inserted into the seat by causing rotation of the shaft gear. 
   Optionally, the shaft gear is a part of a gearing assembly of the shaft for moving the capper. 
   Optionally, the printhead is incorporated in a printing cartridge which is removably engageable with the printer. 
   Optionally, the capper is incorporated in the printing cartridge. 
   Optionally, the printhead is pagewidth printhead and the capper is a pagewidth capper. 
   Optionally, a pagewidth is about 100 mm. 
   In a sixth aspect the present invention provides a method of assembling a capping mechanism of an inkjet printer, the method comprising the steps of:
         providing a support frame for at least one elongate shaft;   positioning the shaft so as to be supported at its longitudinal first and second ends by the support frame;   positioning a bearing of a fixing plate about the first end of the shaft, the bearing being configured to allow rotation of the shaft, the rotation providing transport of a capper out of, and into, a capping position on a pagewidth printhead; and   slidably engaging the fixing plate with the support frame so as to fix the shaft thereto,   wherein, during the sliding engagement, the elongate shaft pivots about the second end due to the configuration of the bearing.       

   Optionally, in the step of positioning the shaft, the first end of the shaft is passed through a slot of the support frame, the slot being configured to allow movement of the first end during the engagement step. 
   Optionally, in the engagement step, the movement of the first end during the sliding engagement moves the shaft from being at an angle off parallel to the capping position to being parallel to the capping position, the bearing being configured to accommodate the angular movement of the shaft. 
   Optionally, the bearing is configured to only contact the first end of the shaft about a line around the circumference of the shaft throughout the angular movement of the shaft in the engagement step. 
   Optionally, in the engagement step, the fixing plate is slid normal to the capping position so as to slidably engage with the support frame. 
   Optionally, the fixing plate incorporates at least one tab configured to slidably engage with a slot of the support frame in the engagement step. 
   In a further aspect there is provided a method further comprising the steps of:
         positioning a second bearing of a second fixing plate about the second end of the shaft, the second bearing being configured to allow the rotation of the shaft; and   slidably engaging the second fixing plate with the support frame so as to fix the shaft thereto.       

   Optionally, in the step of engaging the first fixing plate, the second bearing is configured to accommodate the angular movement of the shaft. 
   Optionally, the second bearing is configured to only contact the second end of the shaft about a line around the circumference of the shaft throughout the angular movement of the shaft in the step of engaging the first fixing plate. 
   In a further aspect there is provided a method wherein:
         the step of positioning the shaft comprises positioning a plurality of elongate shafts so as to be supported at their longitudinal first and second ends by the support frame;   the step of positioning the bearing comprises positioning a plurality of bearings about the first end of each respective shaft, each bearing being configured to allow rotation of the respective shaft about the first end thereof; and   in the engagement step, the configuration of each of the bearings allows the pivoting of the respective elongate shaft about the second end thereof.       

   In a further aspect there is provided a method wherein:
         the step of positioning the shaft comprises positioning a plurality of elongate shafts so as to be supported at their longitudinal first and second ends by the support frame;   the steps of positioning the first and second bearings of the first and second fixing plates comprise positioning a plurality of first and second bearings about the respective first and second ends of each respective shaft, each bearing being configured to allow rotation of the respective shaft about the first and second ends thereof; and   in the step of engaging the first fixing plate, the configuration of each of the bearings allows the pivoting of the respective elongate shaft about the second end thereof.       

   In a seventh aspect the present invention provides an inkjet printer comprising:
         a body;   a first gear assembly mounted to the body so as to cooperate with a motor gear for driving rotation of the first gear assembly, the first gear assembly having a code feature; and   a second gear assembly mounted to the body so as to cooperate with the first gear assembly to be rotatable therewith, the second gear assembly, in use, cooperating with a capper for capping a printhead so that the rotation of the second gear assembly moves the capper out of and into its capping position,   wherein the code feature of the first gear assembly is arranged to cooperate with a holding feature of a mounting arrangement used to mount the second gear assembly to the body, the code feature being configured so that the cooperation with the holding feature maintains the first gear assembly at a predetermined position during the mounting of the second gear assembly.       

   Optionally, the first gear assembly comprises first and second gears connected by a common shaft, the shaft being supported by the body to mount the first and second gears thereto, the first gear meshing with the motor gear and the second gear meshing with the second gear assembly. 
   Optionally, the first gear incorporates the code feature. 
   Optionally, the code feature is a protrusion arranged to protrude from part of the outer surface of the first gear with respect to the body. 
   Optionally, the protrusion has a semi-cylindrical shape. 
   Optionally, the second gear assembly comprises a third gear mounted to the body by a pin, the third gear meshing with the second gear of the first gear assembly. 
   Optionally, the third gear is an eccentric gear. 
   Optionally, the eccentric gear has an eccentricity feature configured to cooperate with an actuator feature of the capper, the cooperation causing the movement of the capper out of and into its capping position. 
   Optionally, the predetermined position of the first gear assembly is configured to position the eccentricity feature of the eccentric gear of the second gear assembly in a predetermined cooperation with the actuator feature of the capper. 
   Optionally, the eccentricity feature is a protrusion arranged to protrude from part of the outer surface of the eccentric gear with respect to the body. 
   Optionally, the protrusion has a semi-cylindrical shape. 
   Optionally, the eccentricity feature is configured to go into and out of cooperation with the actuator feature of the capper based on the rotated position of the eccentric gear in relation to the capper. 
   Optionally, the predetermined cooperation is configured to maintain the capper in its capping position. 
   In a further aspect there is provided an inkjet printer wherein:
         the first gear assembly comprises two second gears connected by the common shaft, both of the second gears meshing with the second gear assembly; and   the second gear assembly comprises two third gears, both of the third gears meshing with a respective second gear of the first gear assembly.       

   Optionally, each of the third gears has an eccentricity feature configured to cooperate with a corresponding actuator feature of the capper, the cooperation causing the movement of the capper out of and into its capping position. 
   Optionally, the predetermined position of the first gear assembly is configured to position the eccentricity features of the third gears of the second gear assembly in a predetermined cooperation with the actuator features of the capper. 
   Optionally, each eccentricity feature is configured to go into and out of cooperation with the respective actuator feature of the capper based on the rotated position of the third gears in relation to the capper. 
   Optionally, the predetermined cooperation is configured to maintain the capper in its capping position. 
   Optionally, the printhead is incorporated in a printing cartridge which is removably engageable with the printer. 
   Optionally, the capper is incorporated in the printing cartridge. 
   In an eighth aspect the present invention provides a printer comprising:
         a support frame; and   a sheet media pick-up device pivotally mounted to the support frame so as to be pivotable relative to a supply of sheet media, the pick-up device comprising:
           a driven roller arranged to be rotated so as to contact and pick-up sheet media from the supply of sheet media and deliver the picked sheet media to a sheet media transport mechanism of the printer; and   a motor for rotatably driving the roller,   
           wherein the motor and driven roller are arranged to pivot with the pick-up device, the pick-up device being configured to pivot so that the driven roller is consistently positioned to contact and pick-up the sheet media as the supply of sheet media is successively depleted after each pick-up.       

   Optionally, the motor and driven roller are incorporated in a molded body of the pick-up device. 
   Optionally, the driven roller is incorporated in an arm of the molded body, the arm being arranged to position the driven roller on the sheet media, in use. 
   Optionally, the pick-up device further comprises a gear assembly which operationally connects the motor to the driven roller. 
   Optionally, the gear assembly incorporates a plurality of gears which cooperate with one another so as to communicate the rotation of a shaft of the motor to a shaft of the driven roller. 
   Optionally, the motor, driven roller and gear assembly are incorporated in a molded body of the pick-up device. 
   Optionally, the driven roller and gear assembly are incorporated in an arm of the molded body, the arm being arranged to position the driven roller on the sheet media, in use. 
   Optionally, the driven roller incorporates a grip material for gripping the sheet media. 
   Optionally, the grip material is rubber. 
   Optionally, the motor is configured to deliver a maximum torque of 2 mNm. 
   Optionally, the support frame is arranged to support the sheet media supply. 
   Optionally, the supply of sheet media is incorporated in a media cartridge, and the support frame is arranged to removably engage with the media cartridge. 
   Optionally, the driven roller is arranged to contact the sheet media through an opening in a lid of the media cartridge. 
   Optionally, the driven roller is configured to drive individual sheets up an inclined face of the media cartridge through the opening to the sheet media transport mechanism of the printer. 
   Optionally, the pick-up device is configured to pivot the driven roller out of contact with the sheet media when the leading edge of a picked sheet is delivered to, and taken-up by, the sheet media transport mechanism. 
   Optionally, the pick-up device is configured to swing about the pivot so as to position the driven roller back into contact with the sheet media, the swinging motion being configured to allow the driven roller to bounce on the sheet media when it comes back into contact therewith. 
   Optionally, the sheet media is 100 mm by 150 mm photo paper. 
   Optionally, the printer incorporating a pagewidth inkjet printhead for printing on the sheet media transported by the sheet media transport mechanism. 
   Optionally, the sheet media is 100 mm by 150 mm photo paper. 
   Optionally, a pagewidth is about 100 mm. 
   In a ninth aspect the present invention provides a printer comprising:
         a sheet media transport mechanism for transporting sheet media past a printhead;   a pick-up roller arranged to be rotated so as to contact and pick-up sheet media from a supply of sheet media and deliver the picked sheet media to the sheet media transport mechanism; and   a gear assembly for communicating a driving force of a motor to the pick-up roller so as to rotate the pick-up roller,   wherein a first gear of the gear assembly is arranged to disengage from a second gear of the gear assembly substantially at the point of delivery of a leading edge of the picked sheet media to the sheet media transport mechanism so as to cease communication of the driving force of the motor to the pick-up roller.       

   Optionally, the gear assembly is configured to rotate the pick-up roller at a rotational speed which delivers the sheet media to the sheet media transport mechanism at a first speed; the sheet media transport mechanism is configured to transport the sheet media at a second speed; and the first speed is lower than the second speed. 
   Optionally, the first speed is about 5% lower than the second speed. 
   Optionally, the gearing assembly is configured to deliver a gearing ratio of 50:1 from the motor to the pick-up roller. 
   Optionally, the motor is configured to deliver a maximum torque of 2 mNm. 
   Optionally, the first gear is configured to disengage from the second gear due to the increase in rotational speed of the pick-up roller at the point of delivery of the leading edge of the picked sheet media to the sheet media transport mechanism. 
   Optionally, the first gear is configured to re-engage with the second gear substantially at the point of a trailing edge of the picked sheet media leaving contact with the pick-up roller. 
   Optionally, the first gear is configured to re-engage with the second gear due to a driving force of the motor and the decrease in rotational speed of the pick-up roller at the point of the trailing edge of the picked sheet media leaving contact with the pick-up roller. 
   Optionally, the first gear is arranged so as to be pivotable relative to the second gear so as to disengage and re-engage therewith. 
   Optionally, the gear assembly incorporates a plurality of gears which cooperate with one another so as to communicate the rotation of a shaft of the motor to a shaft of the pick-up roller. 
   Optionally, the second gear is arranged on the shaft of the pick-up roller and the first gear is an intermediate gear between the second gear and a third gear of the gear assembly which is arranged on the shaft of the motor. 
   Optionally, the gear assembly comprises at least five gears, and the second and third gears are arranged to communicate with one another via the first gear and fourth and fifth gears of the gear assembly. 
   Optionally, a pivot arm connects a bearing shaft of the first gear and a bearing shaft of the fourth gear, the pivot arm being arranged to pivot the first gear out of mesh with the second gear. 
   Optionally, the motor, driven roller and gear assembly are incorporated in a pick-up device of the printer. 
   Optionally, the pick-up roller and gear assembly are incorporated in an arm of the pick-up device, the arm being arranged to position the pick-up roller on the sheet media, in use. 
   Optionally, the pick-up device is mounted to the printer so as to be pivotable relative to the supply of sheet media. 
   Optionally, the pick-up roller incorporates a grip material for gripping the sheet media. 
   Optionally, the grip material is rubber. 
   Optionally, the supply of sheet media is incorporated in a media cartridge which is removably engageable with the printer. 
   Optionally, the sheet media is 100 mm by 150 mm photo paper. 
   In a tenth aspect the present invention provides a method of picking sheet media in a printer, comprising:
         contacting a pick-up roller with sheet media of a supply of sheet media;   rotatably driving the pick-up roller with a motor via a gear assembly so that the pick-up roller picks up the sheet media and delivers the picked sheet media to a sheet media transport mechanism for transporting sheet media past a printhead; and   substantially at the point of delivery of a leading edge of the picked sheet media to the sheet media transport mechanism by the pick-up roller, disengaging a first gear of the gear assembly from a second gear of the gear assembly to cease the driving of the pick-up roller.       

   Optionally, the driving of the pick-up roller rotates the pick-up roller at a rotational speed which delivers the sheet media to the sheet media transport mechanism at a first speed; the sheet media transport mechanism transports the sheet media at a second speed; and the first speed is lower than the second speed. 
   Optionally, the first speed is about 5% lower than the second speed. 
   Optionally, the gearing assembly is configured to deliver a gearing ratio of 50:1 from the motor to the pick-up roller. 
   Optionally, the motor is configured to deliver a maximum torque of 2 mNm. 
   Optionally, the disengaging of the first and second gears is caused by the increase in rotational speed of the pick-up roller at the point of delivery of the leading edge of the picked sheet media to the sheet media transport mechanism. 
   In a further aspect there is provided a method further comprising, substantially at the point of a trailing edge of the picked sheet media leaving contact with the pick-up roller, re-engaging the first and second gears. 
   Optionally, the re-engaging of the first and second gears is caused by a driving force of the motor and the decrease in rotational speed of the pick-up roller at the point of the trailing edge of the picked sheet media leaving contact with the pick-up roller. 
   Optionally, the second gear is arranged on the shaft of the pick-up roller and the first gear is an intermediate gear between the second gear and a third gear of the gear assembly which is arranged on a shaft of the motor. 
   Optionally, contacting the pick-up roller with the sheet media comprises allowing the pick-up roller to move relative to the supply of sheet media. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
       FIG. 1  shows a perspective view of a cradle unit of a printer; 
       FIG. 2  shows a perspective view of the printer; 
       FIGS. 3A and 3B  respectively show opposite side views of the cradle unit; 
       FIG. 4  illustrates an inserted state of a printhead cartridge in the cradle unit; 
       FIG. 5  shows an exploded view of the cradle unit and a media supply cartridge of the printer; 
       FIG. 6  shows a cross-sectional view of the printer taken along the line I-I of  FIG. 2 ; 
       FIG. 7  shows a partial view illustrating a capper shaft supported by a support frame; 
       FIG. 8  illustrates assembly of a fixing plate onto the support frame; 
       FIGS. 9A and 9B  respectively illustrate the fixing plate without and with a spring fitted; 
       FIGS. 10A and 10B  illustrate assembly of media transport rollers into the support frame; 
       FIG. 11  illustrates assembly of a second fixing plate onto the support frame; 
       FIGS. 12A and 12B  respectively illustrate the second fixing plate without and with a spring fitted; 
       FIG. 13A  illustrates a conventional bearing arrangement for a roller shaft; 
       FIG. 13B  illustrates a bearing arrangement of the fixing plates; 
       FIGS. 14A and 14B  illustrate assembly of a coded gear on the capper shaft; 
       FIG. 15  shows a perspective view of the support frame within a jig and illustrates a holding arrangement for the coded gear; 
       FIGS. 16 and 17  illustrate respective operational positions of the jig; 
       FIG. 18  shows a perspective view of a motor for driving rotation of the capper shaft; 
       FIG. 19  shows a cross-sectional view of an operational arrangement of capping gears with actuator features of a capper of the printhead cartridge; 
       FIGS. 20A and 20B  respectively illustrate the positions of the coded gear, one of the capping gears and associated actuator feature during operation of the capper; 
       FIG. 21  illustrates insertion of a printhead cartridge support in the support frame; 
       FIG. 22  illustrates a media sensor of a print media guide; 
       FIG. 23  shows a perspective view of a media transport drive arrangement mounted on the support frame; 
       FIG. 24  shows a perspective view of a media pick-up device mounted on the support frame; 
       FIGS. 25A and 25B  illustrate assembly of the media pick-up device; 
       FIGS. 26A and 26B  illustrate a disengageble gear assembly of the pick-up device; 
       FIG. 27  shows a perspective view illustrating the mounting of a connection interface; 
       FIG. 28  shows a perspective view illustrating the mounted connection interface; 
       FIG. 29  shows a perspective view illustrating the mounting of print control circuitry; 
       FIG. 30  illustrates various connections of the mounted print control circuitry; 
       FIG. 31  shows a system diagram of the printer; 
       FIG. 32  illustrates an exemplary power regulation and storage circuit; 
       FIG. 33  shows a perspective view illustrating mounting of a key feature; 
       FIG. 34  shows a perspective view illustrating the mounted key feature; and 
       FIG. 35  shows a perspective view of the media supply cartridge. 
   

   DETAILED DESCRIPTION OF EMBODIMENTS 
   A printer  100  is variously illustrated in the accompanying drawings. The printer  100  is intended for use as a digital photo color printer and is dimensioned to print 100 millimeter by 150 millimeter (4 inch by 6 inch) photos whilst being compact in size and light in weight. As will become apparent from the following detailed description, reconfiguration and dimensioning of the printer could be carried out so as to provide for other printing purposes. 
   The printer  100  of the illustrated photo printer embodiment has dimensions of 18.6 cm (W); 7.6 cm (H); 16.3 cm (D), and a weight of less than two Kilograms. The compact and lightweight design of the printer provides portability and ease of use. 
   The printer  100  may be easily connected to a PC via a USB connector 408 (such as a USB 1.1 port for USB 2.0 compatible PCs) and to digital cameras and other digital photo equipment, such as electronic photo albums and cellular telephones, via USB or a PictBridge connector  410 . Direct printing is available when using Pictbridge compatible digital photo equipment. This enables quick and convenient printing of digital photo images. 
   Connection to external power is used, preferably to mains power via a 12 Volt; 2 Amp (or 24 Volt; 1 Amp) DC power converter at power connector  406 . However, the printer may be configured to operate from an internal power source, such as batteries. The printer is configured to efficiently use power, operating with a maximum power consumption of 36 Watts. 
   The printer  100  has three core components: a printhead cartridge  200  housing a printhead and ink supply; a printer or cradle unit  400  for supporting the printhead cartridge and housing a media transport mechanism for transporting print media past the printhead; and a media supply cartridge  600  for supplying the media to the printer. 
   The following detailed description is direct to the cradle unit  400  and media supply cartridge  600 , and therefore detailed description of the printhead cartridge is not provided herein. A full description of a suitable printhead cartridge for use with the cradle unit  400  is described in the 
   Applicant&#39;s simultaneously co-filed U.S. patent application Ser. Nos. 11/293,804, 11/293,840, 11/293,803, 11/293,833, 11/293,834, 11/293,835, 11/293,836, 11/293,837, 11/293,792, the entire contents of which are hereby incorporated by reference. For ease of understanding, a brief excerpt of the description provided in these co-pending Applications is provided below under the heading Printhead Cartridge. 
   Printhead Cartridge 
   The printhead cartridge  200  is an assembly having the necessary components for operation as a printer when mounted to the printer or cradle unit having a media supply. 
   The printhead cartridge has a body which is shaped to fit securely in a complementarily shaped printhead cartridge support bay of the cradle unit (see  FIG. 6 ). The body of printhead cartridge houses a printhead and an ink supply for supplying ink to the printhead and has a capper for capping the printhead when the printhead is not in use mounted thereto. A media path is formed between the printhead and the capper for the transport of print media past the printhead by the media transport mechanism of the cradle unit when the capper is not capping the printhead. 
   The printhead is a pagewidth inkjet printhead. By using a pagewidth printhead it is unnecessary to scan the printhead across print media, rather the printhead remains stationary with the print media being transported therepast for printing. By operating the printhead to continuously print as the print media is continuously fed past the printhead, so called ‘printing-on-the-fly’, the need to stall the media feed for each print line is obviated, therefore speeding up the printing performed. 
   The printer incorporating the printhead of the printhead cartridge is configured to print a full colour page, e.g., one 4 inch by 6 inch photo, in at most two seconds. In other words, the printhead is capable of printing at a minimum of 30 pages per minute up to 60 pages per minute. This high speed printing is performed at high quality as well, with a resolution of at least 1600 dots per inch being provided by the printhead. Such a high resolution provides true photographic quality above the limit of the human visual system. 
   This is achieved by forming the printhead from thousands of ink ejection nozzles across the pagewidth, e.g., about 100 millimeters for 4 inch by 6 inch photo paper. In the illustrated embodiment, the printhead incorporates 32,000 nozzles. The nozzles are preferably formed as Memjet™ or microelectomechanical inkjet nozzles developed by the Applicant. Suitable versions of the Memjet™ nozzles are the subject of a number of the applicant&#39;s patent and pending patent applications, the contents of which is incorporated herein by cross reference and the details of which are provided in the cross reference table above. 
   Brief detail of a printhead suitable for use in the printhead cartridge is now provided. The printhead is formed as a ‘linking printhead’ which comprises a series of individual printhead integrated circuits (ICs). A full description of the linking printhead, its control and the distribution of ink thereto is provided in the Applicant&#39;s co-pending U.S. application Ser. Nos. 11/014,769, 11/014,729, 11/014,743, 11/014,733, 11/014,754, 11/014,755, 11/014,765, 11/014,766, 11/014,740, 11/014,720, 11/014,753, 11/014,752, 11/014,744, 11/014,741, 11/014,768, 11/014,767, 11/014,718, 11/014,717, 11/014,716, 11/014,732, and 11/014,742, all filed Dec. 20, 2004 and U.S. application Ser. Nos. 11/097,268, 11/097,185, 11/097,184, all filed Apr. 4, 2005 and the entire contents of which are incorporated herein by reference. In the illustrated embodiment, the linking printhead has five printhead ICs arranged in series to create a printing zone of a 100.9 millimeter pagewidth (which is approximately four inches). 
   Each printhead IC incorporates a plurality of nozzles positioned in rows (see  FIG. 7 ). The nozzle rows correspond to associated ink colours to be ejected by the nozzles in that row. The illustrated embodiment has ten such rows arranged in groups of two adjacent rows for five colour channels. However, other arrangements may be used. In this arrangement, each printhead IC has 640 nozzle per row, 1280 nozzles per colour channel, 6400 nozzles per IC and therefore 32000 nozzles for the five ICs of the printhead. 
   The nozzles are arranged in terms of unit cells containing one nozzle and its associated wafer space. In order to provide the print resolution of 1600 dots per inch, an ink dot pitch (DP) of 15.875 microns is required. By setting each unit cell to have dimensions of twice the dot pitch wide by five times the dot pitch high and arranging the unit cells in a staggered fashion as illustrated in  FIG. 8 , this print resolution is achieved. 
   Due to this necessary staggered arrangement of the nozzles discontinuity is created at the interface between the adjacent printhead ICs. Such discontinuity will result in discontinuity in the printed product causing a reduction in print quality. Compensation of this discontinuity is provided by arranging a triangle of nozzle unit cells displaced by 10 dot pitches at the interface of each adjacent pair of printhead ICs, as illustrated in  FIG. 9 . This nozzle triangle allows the adjoining printhead ICs to be overlapped which allows continuous horizontal spacing between dots across the multiple printhead ICs along the printhead and therefore compensates for any discontinuity. The vertical offset of the nozzle triangle is accounted for by delaying the data for the nozzles in the nozzle triangle by 10 row times. The serially arranged nozzles rows and nozzle triangles of the printhead ICs together make up the printing zone of the printhead. 
   The printhead cartridge may be operated either in a page-limited mode which sets the number of pages which can be printed using the printhead cartridge (e.g., 200 photo pages) or an ink-limited mode which sets a maximum number of pages that can be printed without depleting the ink of the (non-refillable) ink supply. In this way, the printhead cartridge is caused to be operational within the operational lifetime of the printhead nozzles and within the supply of ink for full colour printing. Other suitable modes for ensuring consistent print quality may also be used. 
   The arrangement and operation the capper is described in the Applicant&#39;s co-pending U.S. patent application Ser. Nos. 11/246,676, 11/246,677, 11/246,678, 11/246,679, 11/246,680, 11/246,681, and 11/246,714, all filed Oct. 11, 2005 and the entire contents of which are hereby incorporated by reference. 
   For ease of understanding, a brief excerpt of the description provided in these co-pending Applications is now provided. As illustrated in  FIG. 19 , the capper  202  of the printhead cartridge  200  has an elongate cap  204  which is biased by springs  206  into its capping position on the printhead. The cap  204  has lugs or actuation features  208  protruding from each longitudinal end which are used to move the cap into and out of its capping position. 
   In the capping position, the contact surface of the pad, which defines the capping zone, sealingly engages with the nozzles of the printhead thereby capping or covering the nozzles. This capping isolates the ink within the nozzles from the exterior, thereby preventing evaporation of water from the primed ink from the nozzles and the exposure of the nozzles to potentially fouling particulate matter during non-operation of the printhead. In the non-capping position, the contact surface is disengaged from the nozzles, allowing printing to be performed. 
   The manner in which the capper  202  is operated in cooperation with the cradle unit  400  when the printhead cartridge  200  is mounted to the cradle unit  400  is described in detail later. 
   Cradle Unit 
   The printer or cradle unit  400  is an assembly having the necessary components for operation as a printer when the printhead and media supply cartridges are mounted. 
   From the exterior, the cradle unit  400  has a body  402  and a lid  404  hinged to the body  402 . The body  402  houses the power connector  406 , the data (USB and PictBridge) connectors  408  and  410 , a media supply cartridge slot  412 , a printed media exit slot  414 , which is normally covered with a pivotable flap  416 , and a control panel  418 . 
   With the lid  404  hinged in its open position, a levered frame  420  is exposed. The open position of the levered frame  420  allows access to a printhead cartridge support bay  422  for insertion and extraction of the printhead cartridge  200 . The closed position of the levered frame  420 , via a snap fit of a clip  424  with a release detail  426  of the body  402 , secures an inserted printhead cartridge in operational position. 
   The printhead cartridge support bay  422  and release detail  426  are part of an upper portion  428  of the body  402  which cooperates with a lower portion  430 . The cooperation of the upper and lower portion  430   s , which are preferably plastic moldings, creates an outer shell of the body  402  used to house the internal components of the cradle unit  400 . 
   The internal components are shown in exploded and cross-sectional views in  FIGS. 5 and 6 . For ease of understanding, the following description of the internal components of the cradle unit  400  and their relationship with the body  402  and printhead and media supply cartridges is made in terms of their assembly to form the cradle unit  400 . 
   An elongate capper shaft  432  is inserted at either end into a support frame  434  by feeding the ends through slots or apertures  436  arranged on opposite sidewalls  434   a  of the support frame  434 . The sidewalls  434   a  of the support frame  434  are joined by a base  434   b . The capper shaft  432  has a gear  438  fitted at either end which form part of a gearing assembly for operating the capper of the printhead cartridge. 
   A first end of the capper shaft  432  is fixed in place by a fixing plate  440  which is mounted to the support frame  434  as illustrated in  FIG. 8 . The fixing plate  440  has a number of tabs or hook features  442  (six are shown in  FIGS. 8 and 9A ) and a roller or ring bearing  444  for locating the first end of the capper shaft  432 . The bearing aperture is arranged to align with the apertures  436  of the support frame  434  through which the capper shaft  432  projects. The bearing  444  is configured to allow the capper shaft  432  to rotate. 
   To assemble, the hook features  442 , which have an “L” shaped profile as can be seen in  FIG. 9A , are engaged with slots  446  in the support frame  434  whilst ensuring that the first end of the capper shaft  432  locates in the bearing aperture. The hook features  442  are configured to flex snap within the slots  446  so as to secure the fixing plate  440  to the support frame  434  by sliding of the hook features  442  within the slots  446 . In this way, first end of the capper shaft  432  is fixed to the support frame  434 . In the present embodiment, the hook features  442  are configured so that the fixing plate  440  is slid two millimeters before being secured, as shown by the arrow in  FIG. 8 . Additional securement of the fixing plate  440  may be provided by suitable means, such as screws. 
   The fixing plate  440  has a locator  448  for an elongate idler roller  450  and further roller or ring bearings  452  for locating an elongate entry or drive roller  454  and an elongate exit roller  456 . The drive, idler and exit rollers are part of a media transport mechanism of the cradle unit  400 . The rollers are assembled into the support frame  434  by passing them through associated apertures  458  in the sidewalls  434   a  of the support frame  434  and then into the locator  448  and bearings  452 , which are aligned with the support frame apertures  458 , as illustrated in  FIG. 10A . The rollers are thereby fixed at their first ends to the support frame  434  by the fixing plate  440 , as illustrated in  FIG. 10B . 
   The idler roller  450  has its own bearings on the roller shaft at either end, which locate within the locator  448  so that the idler roller  450  can rotate. The bearings  452  of the fixing plate  440  are also configured so that the drive and exit roller  454 , 456  can rotate. Suitable thrust washers and the like may also be used on the rollers to facilitate location and rotation. 
   The second ends of each of the capper shaft  432  and drive, idler and exit rollers  454 , 450 , 456  are fixed to the opposite sidewall  434   a  of the support frame  434  by a second fixing plate  460 . As with the first fixing plate  440 , the second fixing plate  460  has a number of “L” shaped hook features  442  (six are shown in  FIGS. 11 and 12A ) which are engaged with slots  446  in the support frame  434  to flex snap therein by sliding of the hook features  442  within the slots  446 , as shown by the arrow in  FIG. 11 . 
   Further, as with the first fixing plate  440 , the second fixing plate  460  has roller bearings  444  and  452  for locating the second ends of the respective capper shaft  432 , drive roller  454  and exit roller  456  and a locator  448  for locating the bearing on the second end of the idler roller  450  (as illustrated in  FIG. 11 ). Again, the bearing apertures are arranged to align with the apertures of the support frame  434  through which the capper shaft  432  and rollers  454 , 456  project and the bearings  444 , 452  are configured to allow the capper shaft and rollers to rotate. 
   The locators  448  of the fixing plates  440 , 460  for supporting the idler roller  450  shaft are illustrated in  FIGS. 9A ,  9 B,  12 A and  12 C. As can be seen from these drawings, the locators  448  are each formed as an arm  462  which projects from a flexible pivot point  464  into a slot  466  formed in the fixing plates  440 , 460 . The idler roller  450  shaft locates in a hole  468  in the arms  462 . Springs  470  locate on protrusions  472  on the arms  462  so as to be compressed and held between the arms  462  and protrusions  474  on the fixing plates  440 , 460 . The springs  470  allow the idler roller  450  to move relative to the drive roller  454 , which is located beneath the idler roller  450  as seen in the drawings. The range of movement is controlled by the springs  470  which ensures that the idler roller  450  returns to its stationary position. This stationary position sets a minimum gap between the drive and idler rollers and the movement facilitates the transport of media between the drive and idler rollers. 
   In particular, the minimum gap is set to be less than the thickness of the print media which is to be transported by the drive and idler rollers. In the present embodiment, the minimum gap is set to be about 200 microns when photo paper having a thickness of at least 250 microns is used. Media of other thicknesses could be used, and therefore other suitable minimum gaps set. 
   The sprung movement of the idler roller  450  away from the drive roller  454  allows the media to pass therebetween whilst being contacted by both the drive and idler rollers as the drive roller is rotationally driven (described in detail later). This ‘pinch’ of the rollers  450  and  454  on the media ensures that appropriate friction is imparted on the media for trouble-free and effective transport. 
   In the present embodiment, the drive roller  454  is provided as a plain shaft roller having a substantially gripless surface. That is, the plain shaft is not provided with a grip or grit surface or other friction providing surface. The Applicant has found that, surprisingly, the effective pinch of the rollers is retained in the printer  100  when such a gripless drive roller  454  is used. A gripless idler roller may also be used. In the illustrated embodiment, the drive roller  454  has a smooth surfaced tubular sleeve  476  (two are illustrated in the drawings) arranged on a shaft. The tubular sleeve may be, for example, formed from smooth plastic or rubber. 
   As can be seen from  FIG. 6 , the path of the media from the pinch of the drive and idler rollers  450 , 454  to the exit roller  456  past the inserted printhead is a substantially straight path. By configuring the printing path in this way, high printing speeds and quality are supported. 
   The fixing plates  440 , 460  are preferably plastic moldings with each of the hook features  442 , locators  448 , arms  462 , protrusions  474  and bearing apertures formed as part of the molding. The support frame  434  is preferably press formed from metal to form the illustrated chassis. 
   The bearings  444 , 452  of the fixing plates  440 , 460  are configured to allow pivotal movement of the capper shaft  432  and rollers  450 , 454 , 456  during assembly. This pivotal movement is needed due to the angular mismatch between the first and second ends of the capper shaft  432  and rollers  454 , 456  when they are positioned in the mounted first fixing plate  440  and yet to be mounted second fixing plate  460 . This angular movement of the rigid shaft and rollers is required so that potentially damaging stresses are not placed on the shafts, rollers, bearings and/or support frame. In the final mounted position, the configuration of the bearings  444 , 452  align the capper shaft  432  parallel to the capper and align the rollers  454 , 456  perpendicular to the transport direction of print media. 
   Conventional roller or ring bearings for a shaft/roller are illustrated in  FIG. 13A . As can be seen, due to the flat face of the bearing mount the range of angular movement of a shaft/roller held by the bearings is very limited. 
   The bearing mount or contact face  478  of the roller bearings  444 , 452  of the present invention has an angular or triangular face with respect to the capper shaft  432  and rollers  454 , 456 . As such, a relatively wide range of angular movement of the capper shaft and rollers, characterised by pivotal movement about the first end of the capper shaft and rollers as illustrated by the solid and dashed depictions in  FIG. 13B , is made possible. 
   Other suitably configured bearing mounts or contact faces may also be used, so long as the required range of angular displacement of the capper shaft  432  and rollers  454 , 456  is accommodated. The range of angular displacement to be accommodated may be of the order of about one or two degrees. The sprung locators  448  of the fixing plates  440 , 460  similarly provide for the angular movement of the idler roller  450  during assembly. 
   Further, the slots/apertures  436 , 458  of the support frame  434  are configured so as to accommodate the linear movement of the capper shaft and roller ends during assembly. The additional space provided within the slots/apertures does not cause any unwanted movement of the capper shaft and rollers once assembled due to the rigid capture of the capper shaft and rollers by the fixing plates  440 , 460 . 
   With the capper shaft  432  held in position to the support frame  434  by the fixing plates  440 , 460 , a third gear  480  of the gearing assembly is fitted to the second end of the capper shaft  432  at the exterior of the fixing plate sidewall, as illustrated in  FIGS. 14A and 14B . The gear  480  is arranged to communicate with a motor  482  for driving rotation of the capper shaft  432  (discussed later). 
   The gear  480  is provided with a code feature  484  formed as a protrusion from the outer surface of the gear with respect to the gear&#39;s teeth. In the illustrated embodiment, the code feature protrusion has as a half-cylindrical shape, however, other types of protrusions may be used. Preferably, the gear and protrusion are formed as a molding. 
   The code feature  484  is arranged to cooperate with a holding feature  486  of a jig or mounting arrangement  488  used in the next stage of assembly. As illustrated in the magnified portion of  FIG. 15 , the holding feature  486  comprises a slider block  490  which is slid into position about the code feature  484 . In this way, uncontrolled rotation of the capper shaft  432  is eliminated during this assembly stage. Such rotation is unwanted due to the need to maintain correct capping timing in order to ensure correct and efficient operation of the capper. 
   The jig  488  is used to mount further gears of the gearing assembly of the capping mechanism to the support frame  434 . The further gears are eccentric gears  492  having an eccentricity or cam feature  494 , as illustrated in  FIGS. 17 and 19 . The eccentric gears  492  are positioned on associated retaining pins  496  on plungers  498  arranged on an arm  500  of the jig  488 . The jig arm  500  is pivoted down to and locked at a mounting position for the eccentric gears  492  (see  FIG. 16 ). The plungers  498  are then used to locate the eccentric gears  492  via the retaining pins  496  in apertured features  502  of the fixing plates  440 , 460  adjacent the bearing apertures for the capper shaft  432  (see  FIG. 17 ). The retaining pins  496  are then held in place by suitable clips  504 , such as “E” clips, which are positioned on the pins at the exterior of the support frame sidewalls  434   a , 434   b  whilst the jig  488  is in place ( FIG. 18  illustrates one of the clips in place). The eccentric gears  492  are provided with bearings to freely rotate about the retaining pins. 
   During the location of the eccentric gears  492 , the teeth thereof mesh with the teeth of the gears  438  positioned on the capper shaft  432 , where this meshing is used to transfer rotation of the shaft gears  438  to the eccentric gears  492 . Without the engagement of the code and holding features, this meshing may cause the aforementioned uncontrolled rotation of the capper shaft  432 , placing the eccentric gears  492  in an unknown position. 
   Once the eccentric gears are clipped in place, the assembly is removed from the jig. Whilst the illustrated embodiment uses the jig to mount the eccentric gears to the support frame, some other means of mounting the eccentric gears, including by picker robot or hand, is possible, so long as a holding feature is provided to engage and hold the code feature of the coded gear during mounting. 
   The motor  482  for driving the capping shaft  432 , and in turn the eccentric gears  492 , is fitted into a seat  506  formed in the second fixing plate  460 , as illustrated in  FIG. 18 . A worm gear  508  located on a shaft of the motor  482  is meshed with the coded gear  480  of the capper shaft  432 , in order to transfer motor force to the capper shaft. 
   Some rotation of the coded gear occurs during the meshing of the coded and motor gears. However, as the position of the eccentric gears is known this rotation can be corrected at power up of the printer to correctly position the eccentricity features of the eccentric gears (discussed later). 
   The eccentricity feature  494  of each eccentric gear  492  is formed as a protrusion from the outer surface of the eccentric gear with respect to the eccentric gear&#39;s teeth. In the illustrated embodiment, the eccentricity feature protrusion has as a semi-cylindrical shape, however, other types of protrusions may be used. Preferably, the eccentric gears and protrusions are formed as a molding. 
   The eccentricity features  494  are used to operate the capper of the printhead cartridge  200 . In the normal position of the eccentric gears  492 , the eccentricity features  494  are positioned so that an open part  494   a  of the eccentricity features  494  faces towards the position of the capper when the printhead cartridge  200  is inserted into the cradle unit  400  (see  FIG. 6 ). In this way, the lugs  208  on the capper  202  locate within the eccentricity features  494 , as illustrated in  FIGS. 19 and 20A . In this arrangement, the cap  204  of the capper  202  is positioned against the printhead. 
   When it is desired to print, the motor  482  is operated to rotate the capper shaft  432  via the coded gear  480 . This causes rotation of the eccentric gears  492  via the shaft gears  438 . The gear train of the capping mechanism provides a gearing ratio of 40:1 at the capper. The eccentricity features  494  have cam contact faces  494   b  which contact the lugs  208  of capper  202  during this rotation. This contact causes a lowering force on the lugs  208  which is transferred to the sprung cap  204 , 206  of the capper  202 , thereby lowering the cap  204  and exposing the printhead for printing. The rotation is ceased once the open part  494   a  of the eccentricity features  494  faces away from the position of the capper  202 , as illustrated in  FIG. 20B . 
   When printing is complete or capping is otherwise desired, the motor  482  is again operated to rotate the eccentric gears  492  until the open part  494   a  of the eccentricity features  494  again faces toward the capper  202 . In this position, the lugs  208 , and therefore the sprung cap  204 , return to the capped position. 
   Returning to the assembly, a printhead cartridge support  510  is positioned in the support frame  434 , as illustrated in  FIG. 21 . The sidewalls  434   a  of the support frame  434  are designed to flex to allow insertion of the printhead cartridge support  510 . Once inserted, the printhead cartridge support  510  is held in the support frame  434  by the engagement of the apertured features  502  for holding the eccentric gears  492  and slotted features  512  in the printhead cartridge support  510 . The printhead cartridge support  510  supports, in cooperation with the upper portion  428  of the body  402 , the printhead cartridge and provides reference alignment of the printhead with respect to the cradle unit when the printhead cartridge is inserted into the cradle unit. 
   The printhead cartridge support  510  has spike wheels  514  (see  FIG. 5 ) which cooperate with the exit roller  456  to assist the ejection of print media from the printhead. A print media guide  516  for guiding the print media past the printhead is also provided in the printhead cartridge support  510 . The print media guide  516  includes a flexibly mounted foil  518  for providing a resilient guiding force on the leading edge of the print media transported from the media supply cartridge  600  by the drive and idler rollers  450 , 454  as the media enters a media slot  520  of the media guide  516  (see  FIGS. 5 ,  6  and  21 ). The foil is preferably made of Mylar. 
   A media sensor  522  is provided in the media guide  516  (see  FIG. 22 ) for sensing the leading and trailing edges of the print media so that printing may be accurately controlled based on the position of the print media relative to the printhead. This is achieved by the accurate positioning of the media sensor  522  in the mounted printhead cartridge support  510  which provides a fixed offset between the media sensor  522  and the first row of printhead nozzles. An offset of the order of 33 millimeters provides a sufficient delay between a sensed leading edge and start of printing. The illustrated media sensor  522  is an opto-electric transceiving sensor which emits light into the media slot  520  and senses the amount of light return. When media is in the light path, a change in the amount of light is detected. 
   With the printhead cartridge support  510  in place, a media transport drive arrangement is assembled on the support frame  434 . This is done by fitting pulley wheels  524  onto the first ends of the drive and exit rollers  454 , 456 , mounting a drive motor  526  with associated inertia flywheel  528  and pulley wheel  530  in a motor bay  532  of the printhead cartridge support  510 , mounting a tensioner  534  to the sidewall  434   a  of the support frame  434  and feeding a drive belt  536  over the pulley wheels  524 , 530  and tensioning it with the tensioner  534  (see  FIG. 23 ). 
   The tensioned drive belt  536  transfers the driving force of the drive motor  526  to the pulley wheels  524  and therefore the drive and exit rollers  454 , 456 . The resultant rotation of the drive and exit rollers is used and controlled to transport the print media from the media supply cartridge past the printhead of the inserted printhead cartridge and out through the printed media exit slot  414  in the body  402 . 
   In the illustrated embodiment, the drive belt is a smooth endless belt, and the tensioner is used to provide proper operational tensioning of the smooth belt about the smooth pulley wheels. However, a corrugated or like drive belt may be used in conjunction with toothed pulley wheels. 
   An encoder disc  538  is fitted on the second end of the drive roller  454  and an encoder sensor  540  is mounted to the sidewall  434   a  of the support frame  434  for sensing the position of the encoder disc  538  and therefore the rotational speed of the drive motor  526  (see  FIGS. 5 and 24 ). The illustrated encoder sensor is a U-shaped opto-electric sensor which emits light through holes in the encoder disc as the disc is rotated with the drive roller. 
   Returning to the assembly, a media pick-up device  542  is then mounted to the support frame  434 . The media pick-up device  542  comprises a media cartridge support  544  and a picker assembly  546 . The media cartridge support  544  has two hook features  544   a  which are slid into engagement with two apertures  434   c  in the base  434   b  of the support frame  434 . A screw is used to secure the media cartridge support  544  to the support frame  434  (see  FIG. 24 ). The media cartridge support  544  is provided with a ridge  544   b  and details  544   c  on a base  544   d  thereof for facilitating the insertion of, and for supporting, the media supply cartridge  600  (see  FIG. 6 ). The media cartridge support is preferably a plastics molding having the ridge and details. 
   The picker assembly  546  comprises a picker roller  548 , associated gear train  550  and picker motor  552  housed in a body  554 . Preferably the body  554  is a molding having a base  554   a  in which the picker motor  552  is mounted and an arm  554   b  in which the gear train  550  and picker roller  548  are mounted via associated shafts (see  FIG. 24 ). The base  554   a  of the picker assembly  546  is pivotally mounted to the media cartridge support  544  by engaging (molded) pins  554   c  of the picker assembly body  554  with pivot details  544   b  of the media cartridge support  544 , as illustrated in  FIGS. 25A and 25B . In this way, the picker roller is able to move in and out of contact with the media of the media supply cartridge. 
   The illustrated gear train  550  has five gears, including a motor gear  556  located on a shaft of the picker motor  552 , a picker gear  558  located on a shaft of the picker roller  548  and three intermediate gears  560 . With respect to the intermediate gears  560 , the gear  560   a  adjacent (i.e., closest to) the picker gear  558  is a simple gear, whereas the other two intermediate gears  560   b  and  560   c  are compound gears. The (compound) gear train  550  is used to transfer the rotational driving force of the picker motor  552  to the picker roller  548  so that the picker roller  548  is rotated at a predetermined rotational speed. The gear train provides a gearing ratio of 50:1 at the picker roller. The picker roller  548  comprises a grip tyre  548   a  arranged on the roller shaft which grips the sheet media of the inserted media supply cartridge. The grip tyre is preferably made of rubber. 
   Each of the shafts of the picker and intermediate gears are flex fitted into molded details in the picker assembly body via suitable bearings for allowing rotation of the shafts. It is to be understood that more or less gears may be used in the gear train as is suitable with the rotational force delivered by the picker motor and the rotational speed required for the picker roller  548  to successfully and effectively pick-up the sheet media. 
   Whilst the rotation of the picker roller  548  is used to perform the picking of the sheet media, the pivoting of the picker assembly  546  is used to consistently position the picker roller  548  in contact with the sheet media as the sheet media is depleted from the inserted media supply cartridge. 
   In the illustrated embodiment, the picker motor  552  of the pick-up device  542  is located within this pivoting part  546  of the device. Conventionally, picker motors are located external to such a pivoting parts of a media picker. This external positioning means that a powerful, and therefore large, picker motor is required in order to deliver the necessary torque to the roller. The power and size of the picker motor is reduced by locating the picker motor closer to the roller within the pivoting part. For example, a brushed DC motor delivering a maximum torque of 2 mNm (milliNewton meters) can be used for the picker motor. Whereas a motor capable of delivering about 20% more torque is typically required for an externally positioned motor, due to drive train losses experienced in the extended drive mechanism, i.e., losses due to a longer coupling shaft and at least one or more gear reduction stages on the chassis, in addition to the usual gear coupling stage from pick-up assembly pivot to the picker roller  548 . 
   The mounted position of the pick-up device  542  (see  FIG. 6 ) is configured so that the picker roller  548  picks the sheet media from the inserted media supply cartridge and delivers the leading edge of the sheets to the pinch of the drive and idler rollers, which then take-up the sheets for transport past the printhead of the inserted printhead cartridge. 
   In order to ensure successful take-up of the sheets, the picker roller  548  is driven at a rotational speed which is less than the rotational speed of the drive roller  454 . Typically, the picker roller  548  is driven at a speed about 5% lower than that of the drive roller  454 . This mismatch in speed means that the take-up rollers  450 , 454  pull the sheets faster than the picker roller  548  is able to deliver the sheets. The pivoting action of the picker assembly  546  allows the picker roller  548  to come out of contact with the sheet being pulled by the take-up rollers  450 , 454  due to the picker motor not be able to match the increase in speed on the picker roller  548 . 
   Depending on the speed of take-up, the picker roller  548  may bounce and drag on the sheets as they are being taken up due to a swinging motion of the picker assembly  546  about the pivot points  544   b , 554   c . This bouncing and dragging generally has a negligible effect on the take-up of the sheets, however it may cause wear on the rubber grip tyre  548   a  of the picker roller  548  and the bearings of the gear train  550 , and velocity spikes in the transport of the sheets, which are undesired due to the possible effect on the print quality. 
   In an alternative embodiment of the picker device illustrated in  FIGS. 26A and 26B , the drag of the picker roller  548  on the sheets is reduced by disengaging the picker roller  548  from the picker motor  552  during the take-up of the sheets. This is done by arranging one of the intermediate gears on a pivot arm  562  which pivots the gear out of mesh with the other gears when the rotational speed of the picker roller  548  gear increases at the delivery of the leading edge of a sheet to the take-up rollers  450 , 454 . This disengagement allows the picker roller to effectively free wheel thereby reducing the drag on the sheets. The drag is minimised if the pivoted gear is that closest to the picker roller  548  gear due to the bearing and gear mesh friction of each additional gear not being added to the bearing friction of the picker roller  548 . This arrangement is illustrated in  FIGS. 26A and 26B , where the pivot arm  562  connects the shaft of the closest gear  560   a  and the adjacent compound gear  560   b.    
   The pivoted gear  560   a  is configured to be brought back into engagement with the other gears by the driving torque of the picker motor  552  once the trailing edge of the currently picked sheet has been removed by the take-up rollers  450 , 454 . 
   Returning to the assembly, a connection interface  564  for the printhead cartridge  200  is mounted to the cradle unit  400 . The connection interface  564  incorporates a printed circuit board  566  on which power and data connections  568  for the printhead cartridge  200  are arranged. The connection interface board  566  is mounted to the cradle unit  400  by lowering a lower edge  566   a  of the connection interface board  566  into a slot  510   a  of the printhead cartridge support  510  for receiving the printhead cartridge  200  (see  FIGS. 6 and 27 ) and engaging holes  566   b  in the connection interface board  566  with details  510   b  within the slot  510   a  (see  FIG. 28 ). The holes  566   b  are engaged with the details  510   b  by tilting the connection interface  564  board against a face  510   c  of the printhead cartridge slot  510   a . A tilt angle of up to 1.5 degrees may be accommodated. In this mounted position, the power and data connections  568  are exposed for connection to like connections of the inserted printhead cartridge  200 , as illustrated in  FIG. 6 . 
   Print control circuitry  570  is then mounted to the body  402  of the cradle unit  400 . The print control circuitry  570  incorporates a printed circuit board  572  on which a print controller  573 , the power connector  406  and the data connectors  408 , 410  are arranged. The print control circuitry board  572  is mounted by engaging a connection header  572   a  with a complementary connection header  566   c  of the connection interface  564  at the exterior of one of the sidewalls  434   a  of the support frame  434  and securing the board  572  with screws or the like to that sidewall (see  FIGS. 29 and 30 ). The mating of the connection headers provides complete connection of power and data to the printhead cartridge via the connection interface. 
   In the illustrated embodiment, the connection header  572   a  of the print control circuitry  570  is a male header and the connection header  566   c  of the connection interface  564  is a female header, and the connection interface board  566  projects substantially orthogonally to the print control circuitry board. Other arrangements are possible. During this connection, slight movement of the connection interface  564  board is possible on the details  510   b  within the slot  510   a  since an upper edge  566   d  of the connection interface board  566  is free to move. This movement facilitates the mating of the connection headers and accommodates the tilt angle of the connection interface board. 
     FIG. 31  is a system diagram illustrating the connections between the connection interface  564 , the print control circuitry  570 , the internal components of the cradle unit  400 , the printhead cartridge  200 , a camera connected at the PictBridge connector  410 , a PC connected at the USB connector  408  and an external power supply connected at the power connector  406 . 
   The print control circuitry board  572  has a capper sensor  574  for sensing a position of the capper (see  FIG. 29 ). The illustrated capper sensor  574  is configured as a U-shaped opto-electric sensor through which the half-cylindrical code feature  484  is able pass as the coded gear  480  is rotated. The capper sensor emits and senses light which is uninterrupted when the code feature is in the (capped) position shown in  FIG. 20A  and is interrupted when the code feature is in the (uncapped) position shown in  FIG. 20B . 
   The capper sensor  574  is used by the print control circuitry  570  to operate the capper motor  482  to position the capper out and into its capped position. The capper sensor  574  is also used to reposition the eccentricity features  494  of the eccentric gears  492  in order to correct the movement caused by the aforementioned meshing of the coded and motor gears  480  and  508  during assembly. 
   The print control circuitry board  572  also has connection ports  576  for connecting the capper motor  482 , the drive motor  526 , the encoder sensor  540 , the picker motor  552  and the media sensor  522  to the power supply and print control circuitry, as illustrated in  FIG. 30 . 
   Various control buttons  578  and indicators  580 , such as LEDs, for the function and control of the printer  100  are also incorporated on the print control circuitry board  572 . The control buttons  578  include an on/off button and a print function button, where the print function button may be operated by a user to control functioning of the printer  100 , such as media feed, reprint, creation of print effects, etc. The indicators  580  may include operation status, print status, printhead cartridge, ink volume, media supply, PC/camera connection, etc, indicators. The buttons and indicators  578 , 580  are positioned to locate within the control panel  418  when the upper portion  428  of the body  402  is assembled onto the support frame  434  (see  FIG. 5 ). 
   The complexity of the print control circuitry  570  is minimised by arranging certain circuitry in the connection interface  564 . In particular, power regulation circuitry  582  and/or power storage circuitry  584  is integrated in the connection interface  564 . 
   The power regulation circuitry  582  regulates the supply of power from the external (or internal) power supply via the print control circuitry board  572 . Such regulation is needed in order to ensure that constant and consistent power is delivered to the ink ejection nozzles of the printhead, thereby maintaining consistent print quality. In particular, the drop ejection of the printhead nozzles is a function of both the supply voltage and the firing pulse width. Each nozzle is configured to eject an ink drop having a volume of about 1.2 picoliters and a velocity of about eight metres per second. If the supply voltage varies significantly, the pulse width needs to be varied to maintain consistent drop quality. Such pulse width variation is undesired and therefore tight regulation is needed. 
   An exemplary power regulation circuit  582  is illustrated in  FIG. 32 . The illustrated regulator is a hysteretic regulator based on an LM3485 control chip, and takes an input voltage V IN  of 12 Volts at an input current of 2 Amps and outputs a regulated voltage V pos  of up to 5.5 Volts at a regulated current of 3.5 Amps to the inserted printhead. The maximum total variation in the output voltage under all load conditions is 100 milliVolts. This variation occurs due to load transients on the output capacitors and the ripple due to the hysteretic control, and is not significant enough to adversely effect the print quality. 
   The power storage circuitry  584  stores at least some of the power supplied from the external (or internal) power supply via the print control circuitry board  572 . Such storage is desired to account for potential power shortages during operation of the printhead, thereby maintaining consistent print quality. Power storage also takes account for brief peaks in the nozzle current consumption which is dependent upon the image density and print speed of a printing operation. 
   An exemplary power storage circuit  584  is illustrated in  FIG. 32  as part of the regulator  582 . A number of output capacitors  586  and an inductor  588  are provided to store some of the energy supplied to the connection interface  564 . In the illustrated storage circuitry  584 , bulk energy storage of about 12 millijoules is provided by eight 100 microFarad electrolytic (low ESR tantalum) capacitors  586   a , energy storage of about 900 microjoules for fast load transients is provided by six 10 microFarad ceramic capacitors  586   b  and about 60 microjoules of energy is stored by the inductor  588 , which is a 10 microHenry inductor. Further energy storage may also be provided in the printhead itself. 
   With the internal components of the cradle unit  400  assembled and the various connections made, the assembly is encased with the upper and lower portions  428  and  430  of the body  402 , by securing the upper and lower portions to the support frame  434  with screws or the like, and the lid  404  is hingedly attached to the upper portion  428 . 
   In order to ensure the use of a printhead cartridge which is properly configured to operate with the cradle unit  400 , it is possible to arrange a key feature  490  on the cradle unit  400 , as illustrated in  FIGS. 33 and 34 , which only allows the insertion of a printhead cartridge having a complementary key feature. Such ‘branding’ of the cradle unit  400  and printhead cartridge can be carried out after manufacture. 
   Media Supply Cartridge 
   The media supply cartridge  600  is an assembly of a sheet media support  602  and a hinged lid  604 , as illustrated in  FIGS. 5 and 35 . The sheet media support  602  is dimensioned to support a stack of sheet media on its base  606 , such as 200 sheets of 4 inch by 6 inch photo paper. The lid  606  is hinged on the media support  602  so as to facilitate filling and re-refilling of the media stack. The support and lid are preferably plastic moldings or pressed metal. 
   A spring  608  is located within the media support  602  for maintaining a position of the stack within the media support. In the illustrated embodiment, the spring  608  is located on one sidewall  610  of the media support  602  (see  FIG. 5 ), however other arrangements or the use of more than one spring or other biasing means is possible. 
   The media supply cartridge  600  is inserted into the media supply cartridge slot  412  of the cradle unit  400  so as to locate in the media supply cartridge support  544  of the pick-up device  542 . The media supply cartridge  600  is held in place by the engagement of recesses  612  in the cartridge  600  with (molded) details  544   e  of the media cartridge support  544  (see  FIGS. 1 and 35 ). 
   As described earlier, the ridge and details  544   b  and  544   c  of the media cartridge support  544  facilitate the insertion of the media supply cartridge  600 . A taper of the details  544   c  in conjunction with the ridge  544   b  result in the media supply cartridge  600  being held at an angle with respect to the base  544   d  of the cartridge support  544  (see  FIG. 6 ). This angle on the sheet media, facilitates the pick-up of the sheets by the picker roller  548 . 
   The lid  604  is formed to have nested openings  614 . The larger opening  614   a  allows unobstructed withdrawal of the sheet media from the media supply cartridge, whilst the smaller opening  614   b  allows unobstructed access to the sheet media by the picker roller  548  of the pick-up device  542  when the media supply cartridge  600  is inserted in the media supply cartridge slot  412  of the cradle unit  400 . 
   The delivery of the sheet media occurs past an inclined front face  602   a  of the sheet media support  602  which is supported by a similarly inclined front face  544   f  of the media cartridge support  544  (see  FIG. 6 ). The angle of the incline is configured to assist in the picking of the sheets as the sheets are depleted from the stack and the stack height decreases. A stepped region  616  is arranged in the base  606  on the sheet media support  602  to further assist in the picking of the last few sheets of the stack. 
   This assistance occurs when the picker roller  548  contacts and presses against the remaining sheets causing the sheets to slightly buckle about the stepped region  616 . The buckling causes the leading edge of the sheets to raise slightly, making it easier for the sheets to be driven up the inclined face  602   a  to the nip of the take-up rollers  450 , 454  by the picker roller  548 . Once the stack has been depleted, the media supply cartridge  600  can be removed from the printer  100  and replaced with a new cartridge or refilled for reinsertion. 
   The number of sheets remaining in a media supply cartridge is monitored by the print control circuitry  570  of the cradle unit  400 . This is done by storing a count of the number of sheets fed from the cartridge as sensed by the media sensor  522  of the media guide  516  and/or storing a count of the number of sheets/pages that have been printed. 
   Alternatively, or in addition, if the media sensor  522  of the media guide  516  senses that a sheet has not been picked by the pick-up device  542  from the media cartridge  600 , by not sensing the leading edge of the sheet, the print controller  570  may, for example, cause a media supply indicator  580  of the control panel  418  to operate and/or display of a media out message on the PC or digital camera connected to the printer  100 , which indicates to a user that either the media supply cartridge is depleted, the media supply cartridge has not been inserted or the media has not been successfully picked from the cartridge and allows subsequent correction by the user. 
   Further, media jams can be detected by the media sensor  522  by sensing that the leading edge of a sheet has passed the sensor  522  but not the trailing edge. In such a case, the print controller  570  can respond by stopping printing and operating the drive roller  454  in the reverse direction to remove the jammed sheet. If this does not work, or alternatively, the print controller may, for example, cause a media jam indicator  580  to operate and/or display of a media jam message on the PC or digital camera connected to the printer  100 , which indicates to a user that a media jam has occurred and allows subsequent correction by the user. 
   While the present invention has been illustrated and described with reference to exemplary embodiments thereof, various modifications will be apparent to and might readily be made by those skilled in the art without departing from the scope and spirit of the present invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description as set forth herein, but, rather, that the claims be broadly construed.