Patent Application
20060226592
1. Field of the Invention
The present invention relates to imaging, and, more particularly, to an apparatus providing a reduction in media skew during a sheet picking operation.
2. Description of the Related Art
In an imaging apparatus, such as an ink jet printer or scanner, various methods and mechanisms are utilized to move media into an imaging zone for printing or scanning. One such sheet picking mechanism includes a pick arm free to pivot about a pivot axis, and a pick roller rotatably mounted to the pick arm for picking a media sheet from a supply tray. The pick arm includes a drive assembly, e.g., a driven gear and one or more idler gears, for driving the pick roller during a sheet picking operation. The choice of materials for construction and tolerance build-up between attached parts, such as between the pick arm and the associated pivot mounting feature, may allow this type of sheet picking mechanism to exhibit excessive motion out of the intended plane of action, thereby imparting an undesirable component of force to the media sheet being picked and causing it to skew rotationally. This skew results in improper placement of the media in the imaging zone. For example, in an ink jet printer, such skew during sheet picking may result in the image being skewed on the printed page.
What is needed in the art is an apparatus that reduces media skew during a sheet picking operation.
The present invention provides an apparatus that reduces media skew during a sheet picking operation.
The present invention, in one form thereof, is directed to a media feeding apparatus. The media feeding apparatus includes a side wall. The side wall has a first side surface and an opposite side surface. A sheet picking mechanism has a pick arm and a pick roller. The pick arm is configured to mount the pick roller. The pick arm has a pivot axis substantially perpendicular to the side wall. A restraint is mounted to the pick arm, wherein at least the first side surface of the side wall is in close proximity to the restraint.
The present invention, in another form thereof, is directed to a method for feeding a media sheet from a media supply tray with a sheet picking device, the sheet picking device having a pick arm and a sheet pick roller rotatably coupled to the pick arm. The method includes defining an intended plane of motion of the pick arm; and restraining the pick arm to movement substantially along the intended plane of motion.
The present invention, in another form thereof, is directed to an imaging apparatus. The imaging apparatus includes an imaging engine for performing an imaging operation with respect to a media sheet. A media tray holds the media sheet prior to the imaging operation. The media tray has a side wall, and the side wall has a first side surface and an opposite side surface. A sheet picking mechanism is provided for picking the media sheet from the media tray. The sheet picking mechanism has a pick arm, and the pick arm is configured for mounting a rotatable pick roller. A restraint is mounted to the pick arm. The restraint defines a first restraining feature and a second restraining feature, with a gap between the first restraining feature and the second restraining feature. The side wall of the media tray is positioned in the gap, wherein the first side surface faces the first restraining feature and the opposite side surface faces the second restraining feature.
An advantage of the present invention is that media skew during a sheet picking operation is reduced.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring to
As used herein, the term “communications link” generally refers to structure that facilitates electronic communication between two or more components, and may operate using wired or wireless technology. Accordingly, communications link 24 may be, for example, one of, or a combination of, a bus structure, a direct electrical wired connection, a direct wireless connection (e.g., infrared or r.f.), or a network connection (wired or wireless), such as for example, an Ethernet local area network (LAN) or a wireless networking standard, such as IEEE 802.11.
Controller 12 may be, for example, an application specific integrated circuit (ASIC) having programmed and/or programmable processing capabilities. Controller 12 may include, for example, semiconductor memory, such as for example, random access memory (RAM), read only memory (ROM), and/or non-volatile RAM (NVRAM). Controller 12 may include in its memory a software or firmware program including program instructions that function as a driver for imaging engine 14.
Imaging engine 14 may be, for example, a print engine and/or a scanning device, depending on the type of mechanism and the configuration of imaging apparatus 10. For example, in one embodiment, imaging apparatus 10 may be an all-in-all (AIO) unit having printing and copying functionality in addition to scanning functionality. Accordingly, the driver, as a software or firmware program, executed by controller 12 may include a scanner driver subroutine for controlling a scanning device and for interpreting image data received from the scanner device of imaging engine 14, as well as a printer driver that places print data and print commands in a format that can be recognized by a print engine of imaging engine 14.
In embodiments where imaging engine includes a scanning device, the scanning device may operate using a stationary scan bar, or a moving scan bar, depending on the type of scanning desired or required for a particular scanning application. The scanning device may be, for example, either a CCD (Charge Coupled Device) array or CIS (Contact Image Sensors) array, implemented as image reduction systems or contact imaging systems. Some imaging apparatuses, for example, may utilize the same scanning bar to accommodate either a stationary scan bar implementation or a moving scan bar implementation. In implementations where a stationary scan bar is used, scanning occurs by processing the media sheet with media transport system 18 past the stationary scanner. In implementations where a moving scan bar is used, commonly called a flat bed scanner, the media sheet is typically transported to a stationary position on a document glass platen, and the media sheet is scanned by scanning the scan bar across the stationary media sheet. Further, in the flat bed type scanner, scanning may occur in the media feed direction, or alternatively, in a direction transverse to the media feed direction.
In embodiments where imaging apparatus 10 includes a print engine, the print engine may be, for example, a print engine of any type known in the art for producing a printed output corresponding to image data that is supplied thereto. Such a print engine may utilize one or more of ink jet technology, electrophotographic (e.g., laser) technology, dot matrix technology, or dye sublimation technology. As a more specific example, where imaging engine 14 includes an ink jet print engine, printing may be realized using a reciprocating printhead carrier that carries one or more ink jet printing heads, and operated under the control of controller 12.
Power drive apparatus 16 and media transport system 18 are used to transport a media sheet 26, such as a paper, transparencies, etc., from the stack of media sheets 28 held in media supply tray 20, to, through and from an imaging area 27 of imaging engine 14 to media exit tray 22 in a media feed direction 29.
Media transport system 18 includes a sheet picking device 30 having a pick roller 32; a feed roller set 34 and corresponding pinch roller set 36; and an exit roller set 38 and corresponding backup roller set 40. Power drive apparatus 16 is drivably coupled via a transmission device 42, diagrammatically illustrated by interconnected lines, to each of sheet picking device 30, feed roller set 34 and exit roller set 38.
Power drive apparatus 16 may include as a power source a motor, such as a direct current (DC) motor or a stepper motor. Transmission device 42 may be, for example, a set of gears and/or belts, and clutches configured to transmit a rotational force to the respective rollers at the appropriate time, in conjunction with commands supplied to power drive apparatus 16 from controller 12. Feed roller set 34 and exit roller set 38 may be drivably coupled together, for example, via a pulley/belt system or a gear train.
In the embodiment shown, media supply tray 20 combines with imaging engine 14 to define a media path 44, which in this embodiment defines an L-shaped media path through imaging apparatus 10. It is contemplated, however, that media supply tray 20 may be of other configurations, such as wherein media supply tray 20 is oriented substantially horizontally, such that media path 44 is defined as a substantially flat media path through imaging apparatus 10. As a further alternative, media supply tray 20 may be connected via a C-shaped paper path having additional rollers.
Sheet picking device 30 is configured to automatically pick a media sheet, such as media sheet 26, from the stack of media sheets 28 located in media supply tray 20, and is sometimes implemented in the art by a mechanism commonly referred to as an auto compensator pick device. Sheet picking device 30 includes a pick arm 46 containing a plurality of gears that are drivingly coupled to sheet pick roller 32. Further, sheet pick roller 32 is positioned by pick arm 46 to contact the top media sheet in the stack of media sheets 28 in media supply tray 20. Thus, a media feeding apparatus 48 is formed, at least in part, by media supply tray 20 and sheet picking device 30. The picked sheet is conveyed in media feed direction 29.
In
Referring to
Media supply tray 20 includes a rear wall 62 and a side wall 64. Side wall 64 has a first side surface 66 and an opposite side surface 68. Rear wall 62 supports a media surface of the bottom sheet of the stack of media sheets 28. First side surface 66 of side wall 64 may function as a media guide for the stack of media sheets 28, and, in the orientation of components shown in
A restraint 74 is mounted to pick arm 46, at a distance relative to radius RI from pivot axis 50, for receiving a portion of side wall 64 of media supply tray 20. In one embodiment, for example, restraint 74 is formed integral with pick arm 46.
Ideally, pivot axis 50 of pick arm 46 is perpendicular to first side surface 66 of side wall 64, such that the intended plane of motion 75 of pick arm 46 is substantially parallel to the plane of side wall 64, e.g., extending parallel to media feed direction 29. However, due to component tolerances associated with sheet picking device 30, such as the pivotal coupling of pick arm 46 with the frame F of imaging apparatus 10 via pivot arrangement 53, e.g., a shaft/bushing arrangement, the engagement of pick roller 32 with the media sheet during a sheet picking operation may cause one or more torque forces to be applied to pick arm 46, such as in directions 76 and/or 77 (see
Restraint 74 includes a first restraining feature 78 and a second restraining feature 80. As can be best seen in
Referring to
Clearances between restrain 74 and side wall 64 are selected so as to permit a freedom of motion pick arm 46 along the intended plane of motion 75, while substantially limiting the freedom of motion of pick arm 46 to that of the intended plane of motion 75, e.g., substantially parallel to the plane of side wall 64. For example, in the configuration of restraint 74 in accordance with one exemplary embodiment, first side surface 66 of side wall 64 is in close proximity to first restraining feature 78 of restraint 74, and opposite side surface 68 of side wall 64 is in close proximity to second restraining feature 80 of restraint 74, wherein side wall 64 at times may touch one or both of restraining features 78, 80 during a sheet picking operation without binding within gap 82 of sheet picking device 30.
While this invention has been described with respect to exemplary embodiments, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
