This invention relates to separation strips in a dam for separating adjacent sheets of media being fed from a stack of sheets so that only one sheet is fed to a process station and, more particularly, to separating the uppermost or top sheet of a stack of sheets from the next adjacent sheet during feeding of the top sheet from the stack of sheets of media.
One problem in feeding media from a stack of sheets of media is that the sheets may stick together and at least the next adjacent sheet may be fed at the same time. Accordingly, various separating means have been suggested for separating a top sheet of a stack of sheets of media from the next adjacent sheet when the feed is from the top of the stack of sheets of media and for separating a bottom sheet of a stack of sheets of media from the next adjacent sheet when the feed is from the bottom of the stack of sheets of media.
It is known to separate a top sheet of a stack of sheets from the next adjacent sheet through using a dam, which is an element having an inclined surface in the path of the top sheet, as it is fed from the stack of sheets, so that its leading edge will strike the inclined surface of the element.
In a printer, however, the advancement of more than one sheet from the stack of sheets can cause jamming. Therefore, it is necessary to avoid simultaneous advancement of more than one sheet from a stack of sheets of media to a processing station such as a printer, for example, particularly where a lift plate changes the angle of incident of the sheets of media as the quantity of sheets decrease during operation with each subsequent sheet fed.
Currently, because separation strips are flat, as the media is lifted in the tray, a concomitant change in the pick angle (the angle of the media when the printer “pick” mechanism advances a single sheet), which will then change the “separation angle,” i.e., the angle the media intersects, or “hits,” the separation system. The changing pick angle leads to inconsistent separation of the media as the lift plate moves from tray full to tray empty.
This invention maintains the angle of the media to the separation system throughout the stack height by either actively rotating separation strips as the plate is lifted or is passively achieved by using a curved separation strip surface.
The separation strips rotate at an angle relative to the lift plate to maintain a constant separation angle throughout the media stack height. The separation strips and any other features that are critical to picking and separation could be rotated together to maintain consistent media picking. The rotation of the separation strips may be accomplished using different methods. In one embodiment, gear linkage is used to rotate the strips as the lift plate is lifted. In a second embodiment, the separation strips are rotated independent of the lift plate based on feedback from the printer elements, such as the lift plate motor encoders. In a third embodiment, separation strip surfaces are curved such that the changed incident angle of the media due to the curvature will match the lift plate angle. As the media is lifted, the separation strips curve in toward the media.
An object of this invention is to keep the separation strips at the same relative angle as the lift plate to maintain consistent separation capability of the system and improve media feed reliability.
Other objects of this invention will be readily perceived from the following description, claims, and drawings.
The attached drawings illustrate preferred embodiments of the invention, in which:
Referring to the drawings, and particularly to
The tray 10 has a bottom surface or wall 15 supporting the stack 50 of the sheets 45 therein. The tray 10 has a rear restraint 20 abutting a trailing edge of each of the sheets 45 of the stack 50. Adjacent its front end 12, the tray 10 has an inclined surface or dam 40 integral with the bottom surface 15 of the tray 10.
The dam 40 is inclined at an obtuse angle to the bottom surface 15 of the tray 10 and to the adjacent end of the stack 50 of the sheets 45. The dam 40 is a portion of a surface against which each of the sheets 45 in the stack 50 is advanced into engagement. The sheets 45 are advanced towards a processing station (not shown) at which printing occurs.
Each of the sheets 45 is advanced from the stack 50 by an auto-compensating mechanism (“ACM”) 35, or similar mechanism known to persons of ordinary skill in the art, movable through an operating range including a starting angular position and an ending angular position.
With reference to
The separations strips 100 and any other features that are critical to picking and separation could be rotated together to maintain picking consistency.
The rotation of the separation strips 100 may be accomplished using different methods. Gear linkage (not shown) could be used to rotate the separation strips 100 through the same gear linkage as the lift plate 200 while the lift plate 200 is lifted. Further, the separation strips 100 could also be rotated independent of the lift plate 200 based on information such as lift plate motor encoders.
With reference to
With reference to
While the separation strips 100 of the present invention has been shown and described as being used with a printer, it should be understood that the separation strips 100 of the present invention may be used with any apparatus feeding a sheet 55 from a media stack 50 to a processing station, for example, in which only one sheet at a time is to be fed from the stack to the processing station.
An advantage of this invention is that it is relatively inexpensive to manufacture, being made of a simple material. A further advantage of this invention is that it is very durable, especially if the separation strips 100 are made of Pellethane®. A still further advantage of the present invention is that it is easy to repair or replace if it malfunctions. Another additional advantage of this invention is that it can be used in a printer tray containing a large number of sheets of media.
For purposes of exemplification, particular embodiments of the invention have been shown and described according to the best present understanding thereof. However, it will be apparent that various changes and modifications in the arrangement and construction of the parts thereof may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Number | Name | Date | Kind |
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6059282 | Jang | May 2000 | A |
8757612 | Tsai | Jun 2014 | B2 |
20080211169 | Klein | Sep 2008 | A1 |
Number | Date | Country | |
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20200024091 A1 | Jan 2020 | US |