Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J23/00—Power drives for actions or mechanisms
  • B41J23/02—Mechanical power drives
  • B41J23/025—Mechanical power drives using a single or common power source for two or more functions

Definitions

• the invention relates generally to the field of inkjet printers, and in particular to a mechanical device that enables selective engagement of one or more of a plurality of operational modes of the printer, where each mode is driven by the same motor.
• An inkjet printing system typically includes one or more printheads and their corresponding ink supplies.
• Each printhead includes an ink inlet that is connected to its ink supply and an array of drop ejectors, each ejector consisting of an ink chamber, an ejecting actuator and an orifice through which droplets of ink are ejected.
• the ejecting actuator may be one of various types, including a heater that vaporizes some of the ink in the chamber in order to propel a droplet out of the orifice, or a piezoelectric device which changes the wall geometry of the chamber in order to generate a pressure wave that ejects a droplet .
• the droplets are typically directed toward paper or other print medium (sometimes generically referred to as paper herein) in order to produce an image according to image data that is converted into electronic firing pulses for the drop ejectors as the print medium is moved relative to the printhead.
• Motion of the print medium relative to the printhead may consist of keeping the printhead stationary and advancing the print medium past the printhead while the drops are ejected.
• This architecture is appropriate if the nozzle array on the printhead can address the entire region of interest across the width of the print medium. Such printheads are sometimes called pagewidth printheads.
• a second type of printer architecture is the carriage printer, where the printhead nozzle array is somewhat smaller than the extent of the region of interest for printing on the print medium and the printhead is mounted on a carriage. In a carriage printer, the print medium is advanced a given distance along a print medium advance direction and then stopped.
• the printhead carriage While the print medium is stopped, the printhead carriage is moved in a direction that is substantially perpendicular to the print medium advance direction as the drops are ejected from the nozzles
• the p ⁇ nt medium is advanced, the carnage direction of motion is reversed, and the image is formed swath by swath.
• the examples descnbed in the present invention relate to a carnage pnnter architecture.
• a printer includes a selector pin and a cam member.
• the cam member includes a plurality of paths with each path corresponding to a printer function.
• the cam member and the selector pin are configured to provide relative movement of the selector pin through the plurality of paths with the location of the selector pin in one of the plurality of paths enabling the corresponding printer function.
• a method of driving multiple printer functions using the same motor includes providing a motor; providing a selector pin; providing a cam member assembly including a cam member including a plurality of paths, each path corresponding to a printer function; and relatively moving the cam member and the selector pin through the plurality of paths to selectively permit the motor to drive the corresponding printer function.
• Figure 1 is a perspective illustration of a printer including an embodiment of the present invention
• Figure 2 is a schematic side view showing paper being advanced through the printer
• Figure 3 is a top view of an embodiment of the selector assembly of the present invention.
• Figure 4 is a perspective view of an embodiment of the selector assembly of the present invention.
• Figure 5 is a schematic side view showing paper being advanced in a deskew mode
• Figure 6 is a schematic side view showing a photo paper tray in its forward position
• Figure 7 is a schematic side view showing a photo paper tray in its printing position
• Figure 8 is a perspective view of a second embodiment of the cam member assembly. DETAILED DESCRIPTION OF THE INVENTION
• Figure 1 shows a portion of a carriage printer that includes an embodiment of the present invention.
• Printer chassis 300 has a print region 303 across which carriage 200 is moved back and forth between the right side 306 and the left side 307 of printer chassis 300 while printing.
• Carriage motor 380 moves belt 384 to move carriage 200 back and forth along carriage guide rail 382.
• Printhead chassis 250 is mounted in carriage 200, and ink supplies 262 and 264 are mounted in the printhead chassis 250. Paper, or other print media is loaded along paper load entry direction 302 toward the front 308 of printer chassis 300.
• a variety of rollers are used to advance the medium through the printer, as shown schematically in the side view of Figure 2.
• a pickup roller 320 moves the top sheet 371 of a stack 370 of paper or other media in the direction of arrow 302.
• a turn roller 322 toward the rear 309 of the printer chassis 300 acts to move the paper around a C- shaped path (in cooperation with a curved rear wall surface) so that the paper continues to advance along direction arrow 304 from the rear 309 of the printer.
• the paper is then moved by feed roller 312 and idler roller(s) 323 to advance across print region 303, and from there to a discharge roller 324 and star wheel(s) 325 so that printed paper exits along direction 304.
• Feed roller 312 includes a feed roller shaft 319 along its axis, and feed roller gear 31 1 is mounted on the feed roller shaft 319.
• Feed roller 312 may consist of a separate roller mounted on feed roller shaft 319, or may consist of a thin high friction coating on feed roller shaft 319.
• selector assembly 100 is mounted in association with feed roller shaft 319, and is near feed roller gear 31 1.
• the motor 394 that powers the paper advance rollers is shown schematically in Figure 1.
• Hole 310 at the right side 306 of the printer chassis 300 is where the motor gear (not shown) protrudes through in order to engage feed roller gear 31 1 , as well as the gear for the discharge roller (not shown).
• the maintenance station 330 Toward the left side 307 in the example of Figure 1 (and near the end of the feed roller 312 that is opposite the end where feed roller gear 31 1 is mounted) is the maintenance station 330.
• the electronics board 390 which contains cable connectors 392 for communicating via cables (not shown) to the printhead carriage 200 and from there to the printhead. Also on the electronics board are typically mounted motor controllers for the carriage motor 380 and for the paper advance motor, a processor and/or other control electronics for controlling the printing process, and an optional connector for a cable to a host computer.
• FIG. 3 shows a top view and Figure 4 shows a perspective view of a first embodiment of the selector assembly 100 of this invention.
• Selector assembly 100 includes a cam member assembly 1 10, a spring 130 and a selector pin assembly 140 that are each coaxially mounted on the feed roller shaft 319 in this embodiment.
• Cam member assembly 1 10 includes a cam member 1 1 1 which includes a first cam path 1 12, a second cam path 1 13, a third cam path 1 14 (cam paths indicated as dotted lines in Figure 3), and a stop position 1 15; a sleeve 116; a pushing feature 1 17; and a flange 1 18.
• Cam member assembly 1 10 can optionally be made as an integrally formed part, for example by injection molding.
• each cam path is the stop position 115, while the other end of the three cam paths are slots 122, 123 and 124 respectively.
• Spring 130 is positioned toward the end of the feed roller shaft 319 and is adjacent to flange 1 18 of cam member assembly 1 10.
• the flange 1 18 may have an internal recess inside of which one end of spring 130 is retained.
• the other end of spring 130 is positioned against a wall at the right side 306 of printer chassis 300.
• Selector pin assembly 140 On the other side of cam assembly 1 10, the selector pin assembly 140 is mounted.
• Selector pin assembly 140 which optionally may be made as an integrally formed part (for example, by injection molding), includes selector pin 142 extending radially outwardly from friction mount sleeve 144, and arm(s) 146 also extending outwardly from friction mount sleeve 144.
• Cam member 11 1 cantilevers over friction mount sleeve 144, such that selector pin 142 is captured within the open area of cam member 1 1 1 , and extends through it, as seen more clearly in Figure 4.
• Selector pin 142 is sized to fit into each of slots 122, 123 and 124, as well as into stop position 1 15.
• friction mount sleeve 144 which functions as a type of clutch mechanism.
• the fit of friction mount sleeve 144 on feed roller shaft 319 is sufficiently close that friction mount sleeve 144 will rotate when feed roller shaft 319 rotates, but it is loose enough that friction mount 144 can be rotated independently of feed roller shaft 319.
• the fit of sleeve 1 16 of cam assembly 1 10 is loose enough, or cam assembly 1 10 is optionally constrained rotationally, so that cam assembly 1 10 does not rotate significantly when feed roller shaft 319 rotates.
• Friction mount sleeve 144 is constrained translationally along feed roller shaft 319, so that it may not be moved back and forth significantly along the shaft.
• Cam assembly 1 10 is free to move back and forth along feed roller shaft 319, but is biased toward selector pin assembly 140 by spring 130.
• selector pin assembly 140 (including arm 146) to rotate relative to the feed roller shaft 319. If the carriage 200 is moved to the left in this example, spring 130 pushes cam assembly 1 10 toward selector pin assembly 140 so that selector pin 142 moves along one of the cam paths 1 12, 1 13 or 1 14, the particular path depending upon whether the feed roller 312 is rotated as carriage 200 moves to the left. If feed roller 312 is not rotated, then selector pin 142 moves parallel to the axis of the feed roller shaft 319 along path 1 12 into slot 122.
• Different slots may be reached from the intermediate location by the selector pin 142 following different cam paths. While in the present example, the intermediate location is defined by stop position 1 15 beyond which selector pin 142 can not move, in other embodiments the intermediate location does not need to occur at a stop position.
• arm 146 rotates correspondingly.
• gear engagement / disengagement possibilities that the selector pin assembly 100 of the present invention may enable.
• arm 146 is configured to interact with different gears or gear assemblies, selectively enabling or disabling power transmission from the media feed motor, depending upon its rotational position around feed roller shaft 319.
• a surface of arm 146 may prevent a pivoting gear assembly from rotating into engagement with another gear assembly, while in another rotational position of arm 146, that pivoting gear assembly is free to rotate into engagement with a first gear or a second gear, depending upon the direction of rotation of feed roller shaft 319.
• an arm in one rotational position an arm may push a gear out of engagement with another gear, while in another rotational position, an arm 146 (the same arm, or a different arm, or a different surface of the same arm) may push a gear into engagement with another gear, regardless of direction of rotation of the feed roller shaft.
• a gear that is driven by the media advance motor may be mounted on arm 146 and rotated into or out of engagement with other gears.
• the carriage 200 has enabled the changing of power transmission engagement in this invention, the carriage is free to move away from the selector assembly 100.
• selector assembly 100 of the present invention three separate power transmission engagements are possible (corresponding to selector pin being in either slot 122, 123 or 124), rather than just two.
• there can be even more individually selectable power transmission engagements by designing a cam member 1 1 1 having more than three branches of cam paths.
• four different power transmission engagements could be enabled by the selector assembly 100 shown in Figures 3 and 4.
• a variety of printer functions may be selectively enabled using selector assembly 100.
• a pick function is enabled with selector pin 142 in slot 124
• a printing function is enabled with selector pin 142 in slot 122
• a photo tray movement function is enabled with selector pin 142 in slot 123.
• power from the media advance motor is transmitted to all four of the rollers shown schematically in Figure 2, i.e. pick roller 320, turn roller 322, feed roller 312, and discharge roller 324 and causes them to rotate in forward direction 313.
• the pick roller 320 advances the top sheet 371 to the turn roller 322, the turn roller 322 advances the sheet to the feed roller 312, and the feed roller advances the sheet to the discharge roller 324 when the motor rotates such that the four rollers rotate in forward direction 313.
• the pick function has a second mode called the deskew mode, which is enabled with selector pin 142 in slot 122, but with the media advance motor rotating in reverse.
• the deskew mode may be useful for certain types of jobs, such as printing photos on 4"x6" photo papers.
• the roller motion in deskew mode is indicated in Figure 5.
• the gear from the media advance motor that extends through hole 310 is always engaged with feed roller gear 31 1 and the discharge roller gear (not shown).
• both the feed roller 312 and the discharge roller 324 rotate in reverse direction (opposite 313).
• the pick roller 320 and the turn roller 322 are each connected to power transmission through pivoting gear assemblies, such that even if the motor turns in reverse, the pick roller 320 and the turn roller 322 continue to move in forward direction 313.
• the pick roller 320 and the turn roller 322 advance the paper toward the feed roller 312, but the feed roller 312 is rotating in reverse and resists forward movement of the paper. If the paper is misoriented such that its leading edge is not parallel with the feed roller 312, the first portion of the leading edge that hits reversely spinning feed roller 312 is slowed down until the rest of the leading edge can catch up, thus deskewing the paper.
• the carriage 200 When deskewing is completed, the carriage 200 is again moved to the right such that the pushing feature 1 17 is pushed and the selector pin 142 moves to the stop position 1 15. With the feed roller 312 stationary, the carriage 200 moves to the left, such that the selector pin moves to slot 122 to enable the printing function mode.
• the printing function mode power from the media advance motor is transmitted to forwardly rotate the turn roller 322, the feed roller 312 and the discharge roller 324, but no power is transmitted to the pick roller 320.
• the pick roller 320 disabled, printing media can continue to advance through the printer without the pick roller 320 advancing a next sheet until needed. If the deskew mode of paper advance is being used, then the next sheet cannot be advanced to feed roller 312 until the previous sheet has been discharged, because the deskew mode operates the feed roller 312 and the discharge roller 324 in reverse.
• the pick function forward mode also called the "tailgating mode”
• one sheet can immediately follow the next, with no gap between the two sheets.
• the faster printing throughput tailgating mode is used.
• the tailgating mode begins with the selector pin moved into slot 123 and the paper advance motor rotating all four rollers in the forward direction 313. Once the paper has been advanced to the turn roller 322, the carriage 200 can be moved to the right, pushing the cam assembly 1 10, thus moving the selector pin 142 to stop position 1 15.
• the feed roller 312 is stopped.
• selector pin 142 will be released back to slot 122 into the printing position.
• the carriage 200 moves to the right, pushing the cam assembly 1 10 and releasing it while the feed roller 312 moves forward, so that selector pin 142 moves into slot 124 to enable the pick forward mode for picking the next sheet. Since in this tailgating sequence it is never required to move the feed roller 312 backwards, it is evident that the picking operation can be activated or deactivated at any point during printing. Thus a sheet can be picked immediately after the previous one, with no gaps between the two sheets.
• the timing of switching modes by actuating selector assembly 100 can be adjusted depending upon the length of the sheets of media.
• a third function which can be optionally selected is photo tray movement, for example when selector pin 142 is positioned in slot 123.
• an arm 146 of selector pin assembly 140 causes a gear to engage with a rack (not shown) that can move a photo paper tray back and forth depending on the direction of motor rotation, as in Figures 6 and 7.
• a paper stack 370 in main paper tray 372 and there is a stack of photo paper 373 in photo paper tray 374.
• the sheets in paper stack 370 are of a larger size (for example, 8.5" x 1 1") compared to the sheets in paper stack 373 (for example, 4" x 6"), and photo paper tray 374 is not as long as main paper tray 372.
• the photo paper tray 374 has been moved to its forward position, for example by rotating the paper advance motor in a first direction such that the gear and the rack cause the tray to move forward. In this position, the pick roller 320 is able to contact the top sheet in paper stack 370 in the main tray 372. Also in the forward position of the photo paper tray 374, additional photo paper 373 may be loaded.
• the photo tray 374 has been moved along direction 302 to its printing position, for example by rotating the paper advance motor in a second direction that is opposite the first direction. In the printing position of the photo paper tray 374, the pickup roller 320 is able to contact the top sheet in photo paper stack 373. In some embodiments the pickup roller is mounted on a pivotable pick arm which is able to be moved up or down to rest on the top sheet of whichever tray is beneath it.
• selector assembly 100 While the embodiments above described a particular group of functions that may be enabled by selector assembly 100, various other functions may be enabled in other embodiments. These may include other functions that require motion, such as the maintenance functions of capping, wiping or pumping.
• Selector assembly 100 may be made in other ways than the coaxially mounted cam assembly 1 10, spring 130 and selector pin assembly 140.
• a second embodiment of a selector assembly is shown in Figure 8.
• the functions of the cam assembly 110 and the spring 130 are incorporated together as leaf spring cam assembly 150.
• Leaf spring cam assembly 150 consists of bent thin strip of metal or plastic, for example, and includes a cam member portion 151 with slots 152, 153 and 154 and a stop position 155; a pushing portion 157; and a mounting portion 158 with a hole 159.
• Leaf spring cam assembly 150 may be made by standard metal or plastic forming processes.
• Leaf spring cam assembly 150 operates in much the same way as was described above for the cam assembly 110, and cam member portion 151 has cam paths similar to those in cam member 1 11.
• a selector pin assembly 140 of the same or similar design to that described above operates in conjunction with leaf spring cam assembly 150.
• Feed roller shaft 319 passes through hole 159 in mounting portion 158.
• Cam member portion 151 cantilevers over selector pin assembly 140 such that selector pin 142 is captured within the open slotted region.
• the mounting portion 158 is constrained translationally on feed roller shaft 319, so that in its normal position, cam member portion 151 is located such that selector pin 142 will be positioned in one of the slots 152, 153 or 154.
• the carriage 200 pushes the pushing portion 157, causing the leaf spring cam assembly to bend, and allowing the cam member portion 151 to move parallel to the axis of the feed roller shaft 319 in a direction that locates the stop position 155 at the selector pin 142.
• the restoring force of the leaf spring cam assembly 150 causes it to assume its normal configuration, and selector pin 142 will be located in slot 152, 153 or 154, depending on whether and which way the feed roller 312 turned as the carriage 200 released the pushing portion 157.
• Photo paper tray 380 Carriage motor 382 Carriage rail 384 Belt

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• Ink Jet (AREA)
• Common Mechanisms (AREA)
• Handling Of Cut Paper (AREA)

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• 2008
  • 2008-01-04 US US11/969,277 patent/US8104885B2/en not_active Expired - Fee Related
  • 2008-12-22 WO PCT/US2008/014016 patent/WO2009088449A1/en not_active Ceased
  • 2008-12-22 EP EP08870527A patent/EP2231412B1/en active Active
  • 2008-12-22 JP JP2010541432A patent/JP2011509196A/ja active Pending

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