BACKGROUND
The subject matter of this application relates to print path control in an image formation device, and more specifically enables control of media travel plane, direction, and trajectory change, of media with minimal roller contact and stress on the media and an image formed on the media.
Paper path motion control in image formation devices, such as printers and copiers, typically provide media movement in an “in-line” fashion. Such devices typically employ diverters to provide an angle change when the media is to be transported to a different plane, such as in image formation devices having multiple bins and/or an alternative duplex or exit path.
For example, U.S. Pat. No. 6,487,382 discloses an in-line path of media travel wherein media travels over a plurality of rollers and diverters from a paper supply tray to an exit tray.
The disadvantage of such paper path control systems is that the media, and the image formed on the media, is often in intimate contact with multiple rollers and guides. The rollers and guides impart impressions in the media and potentially degrade the quality of the image due to rubbing contact. As a consequence, additional problems can occur as ink debris collects on and is later transferred from the various roller and guide elements to subsequent prints. Opportunities for stubbing, folding and tearing of the media increase as the number of components contacting the media increases, leading to paper jam reliability problems.
SUMMARY
The subject matter of this application addresses constraints imposed by existing image formation device architectures that require a media path direction reversal and/or movement of media to a different plane. The subject matter of this application also provides devices and methods that are capable of at least elevating and reversing the exit path of the media above an initial trajectory plane.
In known devices, making such a transition would typically require multiple sets of rollers, at least one diverter, and guides that coax the media into a new exit plane. Each of these elements contribute to the degradation of the media and the image quality and increase the difficulty of removing media jams from the image formation device.
An additional feature of the subject matter of this application provides devices and methods for a printer duplex path in which media is not adversely affected as it passes into, and then out of, the media path direction control elements in an image formation device. The subject matter of this application further provides a direction control system that is “invisible” to the normal duplex function so that image and media degradation by contact with media handling components is minimized.
The exemplary embodiment of the media path direction control elements are described as oriented in a chiefly horizontal media path where direction reversal is referenced to the horizontal and offsets are referenced as vertical translations from that horizontal path. This mechanism could just be easily be oriented to function at different angles, such as with a vertical paper path where direction reversal would be in a vertical direction and translation would be an offset from that vertical path.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a front view of an image formation device including an exemplary media path direction control device;
FIG. 2 shows a partial side view of the device of FIG. 1, having the scanner/lid in an open position;
FIG. 3 shows a perspective view of an exemplary embodiment of the media path direction control device;
FIG. 4 shows a perspective view of a lower arm assembly of the device of FIG. 3;
FIG. 5 shows a perspective view of an upper arm assembly of the device of FIG. 3;
FIG. 6 shows a schematic representation of relative arm position during media transport;
FIG. 7 shows a cross-sectional schematic view of an image formation device including an exemplary media path direction control device;
FIG. 8 shows an exemplary series of steps of media path direction control;
FIG. 9 shows a flowchart of an exemplary series of steps of media path direction control; and
FIG. 10 shows an end-view of a carriage with a spring.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIGS. 1 and 2 show an image formation device including an exemplary embodiment of a media path direction control device as shown in FIG. 3.
As shown in FIG. 1, an image formation device 1 includes a scanner/document feeder assembly 2, later simply described as a scanner, a control panel 3, and a print engine 8. The image formation device 1 generally includes a standard paper tray 4 and possibly one or two optional extra paper trays (not shown) disposed below the print engine 8. In the image formation device 1, print media is stored within the body of the image formation device for use by the print engine 8. Upon completion of printing, print media will exit the print engine to the paper exit tray 6 in front of the media path direction control device 10 (FIG. 3). The image formation device 1 may also include a multipurpose tray 5 as often found in image formation devices, shown in the non-functional closed position in FIG. 1.
FIG. 2 shows a partial side view of the image formation device 1 of FIG. 1 having the scanner 2 in an open position. As shown in FIG. 2, with the scanner 2 in the open position, a carriage 7 of the media path direction control device 10 is visible. In normal use, the scanner would be raised as shown to relieve media jams in this area and to replenish print engine ink or toner.
FIG. 3 shows a perspective view of an exemplary embodiment of the media path direction control device 10. As shown in FIG. 3, the media path direction control device 10 includes a paper exit tray 6 which receives print media exiting from the print engine 8 (not shown). An elevator motor 12 is connected to a carriage 7 via a belt 16 (not shown) to alter a vertical position of the carriage 7 to a plurality of positions. A drive motor 14 is connected to the carriage 7 via a belt 16 to drive a plurality of drive rollers 18 to manipulate media through the media path direction control device 10. In an exemplary embodiment, the elevator motor 12 and the drive motor 14 are reversible motors so as to reverse a direction of travel of the mechanism and media. A plurality of idler rollers 20 are disposed on the carriage 7 at a position opposite the drive rollers 18. A nip 46 is formed between the idler rollers 20 and the drive rollers 18 so as to capture and manipulate the movement of media through the media path direction control device 10. Although this exemplary embodiment describes a carriage, other devices, such a shaft, rod, shelf, or the like, are contemplated and are within the scope of the subject matter of this application.
FIGS. 4 and 5 show perspective views of a lower arm assembly and an upper arm assembly of the media path direction control device shown in FIG. 3.
As shown in FIG. 4, the elevator motor 12 is connected to a first pair of parallel arms 26 having an arcuate shape. Each of the arms 26 are pivotably attached to the chassis 44 of the device 10 at a pivot point 38. Each of the arms 26 is also attached or coupled to the carriage 7 (not shown). The arms could be bar shaped, appear as a plate, have numerous other features integrated into them, such as a gear rack, or could be of a variety of shapes or configurations. For simplicity, the general term arm will be used, and lower and upper to distinguish between the two sets. An elevator motor 12 is connected to a stationary drive shaft 28 via a belt 16. The belt 16 is hung around a first pulley 22 connected to the elevator motor 12 and to a second pulley 22 disposed on an end of the lower arm assembly drive shaft 28. The drive shaft 28 is disposed between the pair of parallel lower arms 26. An internal gear rack 24 formed on each of the arms 26 is driven by drive gears 34 disposed near the ends of the drive shaft 28. When the elevator motor 12 rotates the drive gear 34 via the pulleys 22 and the belt 16, the drive gear 34 rotates thereby driving the gear rack 24 to rotate the lower arms 26 about the pivot point 48. When the arm 26 is driven, the gear rack 24 is moveable along a reversible path. The drive shaft 28 distributes a drive force to drive gears disposed at the ends of the drive shaft 28 to cooperatively drive the pair of parallel lower arms 26 thereby rotating the carriage 7 primarily vertically.
FIG. 5 shows a perspective view of an upper arm assembly. A drive motor 14 having a first pulley 22 connected thereto, drives a plurality of drive rollers 18 disposed on an upper arm assembly roller shaft 36. A drive force from the drive motor 14 is imparted to the drive rollers 18 via a belt 16 connected to the first pulley 22 of the drive motor 14, and to a second pulley 22 disposed at an end of the upper arm assembly roller shaft 36. A pair of parallel upper arms 30 is disposed at opposite ends of the upper arm assembly roller shaft 36. The arms 30 are connected at a first end to opposite ends of the roller shaft 36. An opposite end of the arms 30 is connected to the chassis 44 of the device 10 at a pivot point 48. The upper arm assembly roller shaft 36 is coupled to the primarily vertically movable carriage 7. Thus, as the parallel lower arms 26 are driven by the elevator motor 12 to move the entire carriage assembly 7 in a vertical direction, the upper arm assembly roller shaft 36 and the pair of parallel upper arms 30, are cooperatively moved with the carriage 7 as a unit.
FIG. 6 shows a schematic representation of relative arm position during media transport. In an exemplary embodiment, the subject matter of this application employs, among other things, a single roller set mounted to two sets of parallel pivot arms 26, 30 sized such that media transport along a tangent vector between the rollers 18, 20 is angularly optimized to a desired media exit trajectory. For example, as shown in FIG. 6, with the parallel arms 26, 30 at a first position (Position One), the roller set accepts media traveling in a first direction, indicated by the arrow, and allows the media to travel to a point near a trailing edge of the media. Then, by pivoting the two parallel arms to a second position (Position Two), enables the media to be directed to a different path. In FIG. 6, the media is directed in a direction opposite to the first direction indicated by the arrow.
An advantage of supporting each roller 18, 20 on a separate arm is that travel of one arm 30 and the drive roller 18 can be stopped at a position to receive the media 32 and the other arm 26 and the idler roller 20 can be driven to a third position (Position Three) that creates a gap between rollers 18, 20 of the roller set, allowing the print engine 8 to perform a duplex print operation, or other media motion, without significant interaction with the direction control device 10. The gap between rollers 18, 20 in the media path direction control device 10 at Position three significantly reduces concern for differences in roller speed and media transport velocity between the print engine 8 and the media path direction control device 10. Controlling the motion profile of the pivot arms 26, 30 from Position Three to Position One allows the media 32 to be clamped within the exit roller set of the print engine in a benign fashion so that the image and media are minimally affected by the operation.
In an exemplary embodiment, the device 10 has no diverter, no media guides and only a single roller set, thereby ensuring that the direction and transport path change have minimal influence on the media 32 and an image formed thereon.
In an exemplary embodiment, the two pivot arm sets 26, 30 are connected to the motors 12, 14, respectively. The arms 26, 30 are moveable through the elevator motor 12 and the drive motor 14. In an exemplary embodiment, the arms can be of different lengths to establish an optimal trajectory and/or height of the media 32 as the media 32 exits into the paper tray 6 (FIG. 7). In an exemplary embodiment, the elevator motor 12 is controlled to stop arm rotation at various points along a path of travel (Position Two) to complement an increasing (varying) height of a stack of printed media 32 exiting from an print engine 8 into the paper exit tray 6, or for optimal handoff to alternate media paths. In an exemplary embodiment, a sensor system (not shown) determines the approximate height of the existing stack of media and halts operation when the tray 6 is full.
A spring 42 (FIG. 10), is disposed at each end of the carriage 7 coupling the carriage to the upper arm assembly roller shaft 36 to “spring load” the idler rollers 20 against the drive rollers 18. Because the idler rollers 20 of the carriage 7, are individually spring loaded against drive rollers 18, the roller set 18, 20 disposed on the carriage 7, and shaft 36 are held in close contact with one another. Thus, the rollers 18, 20, are free to move with the carriage arms 26, 30 as the carriage arms 26, 30 are driven up and down. In an exemplary embodiment, the idler rollers 20 are also spring loaded so as to be resiliently mounted to the carriage. Idler roller springs 43 would be a commonly used wire form cantilever spring as shown in FIG. 10 to provide such resilience.
Spring loading the carriage 7 provides a convenient way to ensure that the drive rollers 18 follow the carriage 7 through its range of motion. Spring loading each of the idler rollers 20 independently through the idler roller springs 43 ensures that the idler rollers 20 are properly in contact with the drive rollers 18. Spring loading also allows control over the nip 46 formed between the rollers 18, 20. For example, when the upper arms 30 are in their maximum downward pivot position (Position three in FIG. 6), the arms 30 come up against a travel limit stop (not shown). The springs 42 allow the lower arms 26 and the idler rollers 20, of the carriage 7 to continue to move primarily downwardly by overdriving the carriage 7 through the gear rack 24 on the lower arms 26 beyond the limit stop of the upper arms 30 to open up or create a gap between the drive rollers 18 and the idler rollers 20 at the nip 46 (see FIGS. 6 and 8).
The gap between the rollers 18, 20 is created to allow the rollers to separate when media is to be received so that the amount and/or duration of contact between the rollers 18, 20 when receiving the media 32 from the print engine 8 is minimized.
Opening such a gap prevents the media drive system of the print engine 8 from conflicting with the drive systems of the print path media control device 10 (e.g. drive motor 14). In this way almost the entire length of the media 32 travels through the nip 46 with the rollers 18, 20 not in contact with one another. When the media is in the proper position, the elevator motor 12 drives the carriage 7 to an intermediate position (Position one in FIG. 6) clamping the media 32 between the spring loaded rollers 18, 20. The spring loading between these two sets of arms 26, 30 holds the rollers 18, 20 together throughout the rest of the range of movement of the arms 26, 30.
In an exemplary embodiment, during the transfer of media 32 from the print engine to the device 10, carriage 7 is lifted slightly while drive roller 36 is engaged and the rollers 18, 20 grip the media 32 for a brief moment while the media 32 is still in the roller nip of the print engine 8. The media is in the roller nip of the device 10 for only some very small distance. Thus, when both the print engine 8 and the device 10 drive the media together, the trailing edge of that media comes out of the nip from the print engine drive roller to minimize any opportunity for burnishing or wrinkling of the media due to variations or differences in the velocity in the transport systems.
FIG. 7 shows a cross-sectional, schematic view of an image formation device including a diagrammatic representation of an exemplary media path direction control device. As shown in FIG. 7, the image formation device 1 includes a scanner 2, and a print engine 8. The media path direction control device 10 is disposed above the print engine 8 and includes upper and lower parallel arms 26, 30, drive rollers 18 and idler rollers 20. The rollers 18, 20 are connected to the chassis 44 at respective pivot points 48. A controller 50 controls operation of the motors 12, 14 to control movement of the arms 26, 30 and the rollers 18, 20. A plurality of printed media 32 is shown in the paper exit tray 6.
FIG. 8 shows an exemplary series of steps in a perspective similar to the image formation device shown in FIG. 7. As shown at step 1 of FIG. 8, drive rollers 18 and idler rollers 20 are in a noncontact, or open, position to receive media 32 exiting the print engine 8. The media 32 is fed out of the print engine 8 through a gap between the rollers 18, 20. Step 2 shows control of the media 32 being handed over from the print engine 8 to the media path direction control device 10. At a predetermined point of the media travel path during handover, the drive rollers 18 and idler rollers 20 are in a contact, or closed, position forming a nip therebetween to capture the media 32. The drive rollers 18 are driven by the drive motor 14 until the media 32 reaches a predetermined position at a trailing edge of the media. At step 3, the media path direction control device 10 detects that the media 32 is at a desired position and the drive motor 14 halts the drive rollers 18. At step 4, the elevator motor 12 rotates the drive gear 34 to drive the gear rack 24 of the lower arms 26 to drive the carriage 7 vertically upward to move the media 32 to a desired position for deposit in the paper exit tray 6. At step 5, upon reaching the desired height, the drive motor 14 is reversed and the media 32, held in the nip 46 formed between the drive rollers 18 and idler rollers 20, cooperatively drives the media 32 out of the nip 46 for deposit into the paper exit tray 6. At step 6, the elevator motor 12 engages the drive gear in a reverse fashion thereby driving the carriage 7 into a lowered position. When moving to a position to receive the next sheet of print media 32, the elevator motor 12 continues to rotate thereby forcing the carriage 7 downward past the travel limit position separating the drive rollers 18 from the idler rollers 20 so as to receive the next sheet of print media 32 from the print engine 8.
FIG. 9 shows a flowchart of an exemplary method of media path direction control, according to an exemplary embodiment of the subject matter of this application. The process begins with the print engine picking a sheet of media and continues to step S10 whereupon printing of the media in the print engine begins. As the media 32 is printed in the print engine 8, the media 32 moves through the print engine 8 to a point of exit at step S20. As the media 32 exits the print engine 8, the media 32 is received by the media print path direction control device 10 at step S30. As the media 32 moves to a desired position in the media print path direction control device 10, the drive rollers 18 and idler rollers 20 of the device 10 to capture the media 32 at step S40. The device 10 then advances the media 32 to a desired position whereas the trailing edge of the media has exited the print engine in step S45. Upon capture and position of the media 32 at a desired position, the media path direction control device 10 elevates the media 32 at step S50 to a desired position. Upon reaching the desired position, the media print path direction control device 10 reverses the drive rollers 18 to eject the media 32 into the paper exit tray 6 at step S60. The rollers are then positioned to receive the next piece of print media 32 from the print engine 8 at step S70.
Although this invention has been described in conjunction with the exemplary embodiments outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that are or may be presently unforeseen, may become apparent upon reviewing the foregoing disclosure. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope the invention.
Patent Application
20060170748
