BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a side view of an inkjet printer having a media output system in accordance with an embodiment of the present invention.
FIG. 2A shows the inkjet printer of FIG. 1 with an unblocked side view of an extendable output ramp in a retracted position.
FIG. 2B illustrates the operation of the media output system.
FIG. 3 shows a top view of the media output system.
FIG. 4 is a method flowchart for sorting different print jobs using the inkjet printer of FIG. 1 in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
The present invention provides a media output system that is suitable for printing devices such as inkjet printers. This output system is particularly useful for printers in a multi-user environment, such as those used in a typical office network.
Illustrated in FIG. 1 is an exemplary inkjet printer 10 that includes a media output system 20 according an embodiment of the present invention. In the printer 10, a media sheet is directed through a print cycle, which includes picking a media sheet M from an input tray 11, transporting the media sheet over the surface a turn roller 12 then through a print zone 13, and ejecting the wet printed sheet onto a collection tray 14. At least one ink pen 15 is provided in the print zone 13 for forming wet print markings on the surface of the media sheet during printing. Consecutive printed sheets are piled one on top of another as successive sheets are printed and ejected to form an output stack in the collection tray 14. The ejection and sorting of the printed sheets are performed by the media output system 20.
Referring to FIG. 1, the output system 20 includes a plurality of output rollers 16, a plurality of spaced-apart output ramps 17 (i.e., holding members), a plurality of starwheels 18, and the collection tray 14. The output rollers 16 in cooperation with starwheels 18 advance the wet printed sheet from the print zone 13 towards the collection tray 14. As such, the output rollers 16 and the starwheels 18 together form an ejecting mechanism for ejecting the wet printed medium. The output ramps 17 are extendable to different positions in the output direction indicated by arrow D. In order to avoid smearing the wet printed markings of any previously printed sheet, the subsequent printed sheet is held for a predetermined holding time by the output ramps 17 before the printed sheet is allowed to fall onto the collection tray by gravity. By holding the wet printed sheet in this manner, more time is allowed for the wet print markings to dry. This holding time is achieved by forcing the printed sheet to travel a longer distance known as the holding distance.
In an effort to sort and separate different print jobs in an orderly manner, the output ramps are instructed by the firmware of the printer to extend to a different position in the output direction D for each print job until a predetermined number of print jobs have been performed. The firmware is programmed to sort and separate a predetermined number of print jobs and the different extended positions of the output ramps correspond to the predetermined number of print jobs. The result is each subsequent print job being stacked at a position spaced from the immediate previous print job. It is well known to those skilled in the art that an inkjet printer typically has a firmware that is implemented as a permanent memory module and the firmware can be programmed to coordinate the operation of the hardware components within the printer.
FIG. 2A shows a side view of the output system wherein the output ramps 17 are in a fully retracted position, i.e. home position. When printing is not in operation, the output ramps 17 are in the retracted position as shown FIG. 2A. During printing, the output ramps 17 are extendable to different positions in the output direction. As an example, if the predetermined number of print jobs is three, the output ramps 17 are controlled to extend from the fully retracted position to three different extended positions P1, P2, P3 as illustrated by FIG. 2B. In FIG. 2B, position P1 corresponds to print job #1, position P2 corresponds to print job #2, and position P3 corresponds to print job #3. During print job #1, the output ramps extend to position P1 until all the media sheets for print job #1 are printed and ejected onto the collection tray. After print job #1 is completed, the output ramps retract to the retracted position P0. The output ramps then extend to position P2 and print job #2 commences. Position P2 is further away in the output direction D than position P1. After print job #2 is completed, the output ramps again retract to the retracted position P0. During print job #3, the output ramps extend to position P3, which is further away in the output direction than position P2. The result is illustrated by the stacked print jobs J1, J2, J3 in FIG. 2B. In addition, the output ramps 17 incrementally extend in a plane that forms an angle with the bottom surface of the collection tray 14. The extension of the output ramps 17 is adjusted to accommodate the increasing height of the media stack in the collection tray 14 when the printer is performing multiple print jobs. At the same time, the actual drop distance of the printed media to the tray is kept to a minimum. In other words, the height at which the ejected sheets are dropped from the output ramps 17 to the collection tray 14 is adjusted to the minimum in the vertical direction.
Referring again to FIG. 2B, the distance between the distal ends of the output ramps 17 and the bottom surface of the collection tray 14 during position P1 is relatively low as compared to that during position P3. As such, the height of the distal ends of the output ramps 17 relative to the collection tray 14 increases as the height of the stack of printed sheets increases. As a consequence, the dropping distance of the ejected sheets onto the collection tray 14 is shortened, thereby enabling the printed sheets to fall onto the collection tray and be stacked in a more orderly manner.
FIG. 3 shows the top view of the output system 20. The output ramps 17 are mounted along a direction that is substantially orthogonal to the output direction D of the printed sheet so as to support the width of the printed sheet. Each output ramp 17 is positioned between two output rollers 16. The output rollers 16 serve the purpose of moving the printed sheet onto the output ramps 17 and subsequently onto the output collection tray. The amount of rotation of the output rollers 16 is controlled by the workflow in the firmware in the printer and depends on whether the printed sheet is to be driven to the output ramp position P1, P2 or P3.
FIG. 4 is a methodical flowchart for sorting three successive print jobs using the printer 10. At 400, the printer receives an instruction of a print job. Print job differentiation is known in the art, thus, the details of which are not discussed here. At 401, the firmware of the printer determines whether the print job is job #1. If the answer is yes, the output ramps extend to position P1 at 402 and printing commences. At 403, the output ramps return to the retracted position at the end of the print job. The print job counter is reset in the printer at 404. After 404, the printer returns to “start” and blocks 400 and 401 are repeated. If the answer at 401 is no, the firmware determines whether the current print job is job #2 at 405. If the answer is yes, the output ramps extend to position P2 and printing commences. After print job #2 is completed, blocks 403 and 404 are repeated. If the answer at 405 is no, the printer proceeds to block 407, in which the printer senses that a third print job is being sent. Subsequently, the output ramps extend to position P3 at block 408 and printing commences. After print job #3 is completed, blocks 403 and 404 are repeated to retract the output ramps to the retracted position and to reset the print job counter. A print job subsequent to print job #3 would be counted by the printer as print job #1 and the whole flowchart shown in FIG. 4 would be repeated. Although the flowchart for sorting three print jobs has been described, it should be understood by those skilled in the art that more than three print jobs could be sorted using the same logic.
When different print jobs are stacked and sorted as described above, the print jobs could be easily distinguished and collected by the users. Furthermore, the output system of the present invention provides a sorting function without increasing the width or the height of the printer because extraneous hardware components are not required. Moreover, the sorting operation of the output ramps can be done quietly. This is an advantage over conventional sorting systems that require moving large hardware components to do the sorting.
It is intended that that the embodiments contained in the above description and shown in the accompanying drawings are illustrative and not limiting. It will be clear to those skilled in the art that modifications may be made to the embodiments without departing from the scope of the invention as defined by the appended claims.
Patent Application
20070273088
