Paper handling apparatus

Abstract: Height barriers (15a, 15b) on the bottom of the feed arm frame (5) are located a distance above the bottom of paper drawer (1) of a printer (13). The drawer is pulled out to load paper, and then pushed in. If the paper stack (25) is high enough to encounter the barriers, paper which encounters the barrier is pushed off the top of the stack as the drawer moves further. The pushed paper emerges in front of the printer and is removed by the operator. Back restraint (17) is integral with the elevated region (17b) of the drawer, followed by an inclined region (17a).

Description: This invention relates to apparatus for handling paper or other media in an imaging device such as a printer or copier. U.S. Patent No. 5,527,026 discloses a paper pick mechanism which employs a drive roller on a pivoted arm. With such an arrangement, excess paper height is unacceptable as the device requires at least a predetermined downward angle of the arm for reliable functioning. If the stack is too high, the drive rollers tend to slip on the top sheet rather than move it. Accordingly, the paper stack height must be controlled. Additionally, in such apparatus, the preferred implementation of the paper tray employs a sloped, smooth surface, termed a dam, as the initial surface against which the paper is moved by the drive rollers. The dam-style paper tray is essentially a box into which the paper or other media is dropped. There is no physical element, such as the commonly used buckling ledge (termed a comer buckler), under which the media must be positioned. With the absence of a comer buckler, no physical stack limiter is present in the paper tray itself. Typically, a label is placed on the side of the tray to show maximum stack height, and the user must voluntarily comply with the indication on the label. Accordingly, filling the tray above the defined point is easy and might frequently occur, which would contribute to paper feed failures. EP-A-0 655 349 discloses a document container having at least one barrier allowing only a stack of media of a maximum height to be leaded into said document container. According to the present invention there is provided a media height limiting apparatus comprising: a drawer for holding a stack of media to be fed from said drawer; a receptacle in which said drawer may be inserted; and at least one barrier fixedly suspended above where said drawer is inserted, so as to encounter media stacked in said drawer above a predetermined height. Thus in a preferred form of the invention a height barrier is located above a paper drawer. The drawer is pulled out to load paper, and then pushed back in. If the media stack in the drawer is high enough to encounter the barrier, media which encounters the barrier is pushed off of the top of the media stack as the drawer is further moved in. The pushed media will emerge at the front of the drawer. The operator will remove that paper intuitively as it must be removed to complete insertion of the drawer. To assure that the media is not pressed by the height barrier during the next paper feed, the drawer has an elevated bottom region near its side opposite the front or dam side. The height barrier encounters the paper stack initially where it is elevated by being on the elevated region. As the drawer moves further, the elevated region moves past the height barrier. This leaves an empty space under the height barrier and the top of the stack, thereby assuring the barrier does not press the stack when paper is fed. In the specific embodiment, a movable back paper restraint is integral with an elevated region and then an inclined region. An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Fig. 1 illustrates a paper tray drawer, and associated feed and barrier elements of an imaging apparatus, from the right-hand side, and showing one shingling barrier; Fig. 2 is a similar view from the left-hand side, showing a second shingling barrier; Figs. 3a, 3b and 3c are diagrammatic views showing a sequence of operation; and Fig. 4 shows excess paper in position to be removed by an operator of the imaging apparatus. Fig. 1 illustrates a paper drawer 1, which is pulled out to load paper into the drawer. Fixedly suspended on shaft 3 over the location of drawer 1 is a stationary support frame 5 and a pivoted drive arm 7, which drives rollers 9a and 9b which rest on the top of paper in drawer 1. Such driving of paper from a pivoted arm is described in the aforementioned U.S. Patent No. 5,527,026 and forms no part of this invention. Power is supplied to the drive arm 7 by an electric motor 11 which is also supported on frame 5. The frame 5 is permanently supported as part of a paper tray for a printer 13 (Fig. 4). Drawer 1 moves relative to the frame 5 in a receptacle 14 formed by an opening in printer 13. On the bottom right of frame 5 is a downwardly extending barrier tooth 15a, which encounters and shingles paper as will be described. An adjustable rear barrier or restraint 17 is moved manually to a position corresponding to the length of paper or other media stacked in drawer 1 between a front dam 19 and barrier 17. Barrier 17 is held in position by entering a selected one of a series of detent ridges 21, as is conventional. Ledges 22a, 22b on opposite sides of drawer 1 enter slots (not shown) in receptacle 14 which support drawer 1 horizontally as it is moved in and out of receptacle 14. Until drawer 1 is almost fully inserted, a coil spring 23 acting on shaft 3 rotates arm 7 upward so that drive rollers 9a, 9b do not encounter paper. Fig. 2 is a view of the apparatus from the left. A second shingling barrier 15b, also part of frame 5, is located opposite barrier 15a and at the same height with respect to drawer 1. Also shown in Fig. 2 is an upward inclined region 17a, which is integral with rear restraint 17, and a flat region 17b, which is integral with both restraint 17 and inclined region 17a. Region 17b is therefore higher than a region 1a immediately forward of inclined region 17a. Rear barrier 17 is adjustable towards and away from the front dam 19 until incline 17a encounters a permanent barrier 1d. Region 1a is not significantly wider than restraint 17. A region 1b, which is forward and on the side of region 1a, is flat and somewhat higher than region 1a, which is also flat. Paper in drawer 1 is supported on the higher flat region 1b rather than on smaller, lower region 1a. In use, drawer 1 is pulled out and a stack of paper or other media 25 is placed in the drawer. Fig. 3a shows this status before drawer 1 is pushed back to its final position. Fig. 3b shows the status after the drawer has been pushed toward its final position in the direction indicated by arrow 27. As the drawer is moved in this direction the shingling barriers 15a, 15b will strike the trailing edge of media 25 which exceeds a predetermined stack height. As the drawer is further moved to its final position, as shown in Fig. 3b, the shingling barriers 15a, 15b force any such excess media over dam 19 and out of the front of drawer 1. Fig. 4 shows the outside of a printer 13 generally in the status of Fig. 3b with drawer 1 partially inserted. The operator will pull away the excess paper 25, which operation will be intuitive as the excess paper 25 is obviously being rejected and furthermore is preventing full insertion of drawer 1. Drawer 1 can then be inserted to its final position, as shown in Fig. 3c. Arm 7 is rotated to its active position by a camming action of drawer 1 about its final 1/4 inch of insertion, and is therefore now shown in its down position. Shingling barrier 15a, 15b are located over the lower region 1a and do not therefore push down on the stack of media 25. With the drawer 1 so located in its final position, without excess stack height of media 25 and without the media 25 being pinched by barriers 15a, 15b, the paper feed mechanism comprising arm 7 will reliably feed the top sheet of media 25 from the stack in drawer 1. As an alternative to providing a lower level bottom 1a in drawer 1, the drawer could enter a drop area after partial insertion. The drawer would then be inserted as described and come in contact with shingling barriers 15a, 15b so as to pass excess media 25 out, as described above, before the drawer enters the drop area. Upon subsequent movement of the drawer to its final position, the drawer would enter a lower support member so as to cause a gap to exist between the shingling barriers 15a, 15b and the media 25. It will be apparent also that the drawer 1 need not be part of a paper tray which is fixedly integrated into printer 13 as shown in Fig. 4. Instead, one or more paper trays can be attached to printer 13 as accessories, as by stacking them under printer 13.

Claims: A media height limiting apparatus comprising: a drawer (1) for holding a stack of media (25) to be fed from said drawer; a receptacle (14) in which said drawer may be inserted; and at least one barrier (15a,15b) fixedly suspended above where said drawer is inserted, so as to encounter media stacked in said drawer above a predetermined height. Apparatus as claimed in claim 1, in which said drawer (1) has a smooth inclined exit dam surface (19) on the side away from said barrier (15a,15b). Apparatus as claimed in claim 1 or 2, in which a first media supporting region (17b) of said drawer which is under where said barrier (15a,15b) initially encounters said media is higher than a second media supporting region (1a) which is under where said barrier is located upon final insertion of said drawer. Apparatus as claimed in claim 3, wherein there is an inclined region (17a) between said first region (17a) and said second region (1a). Apparatus as claimed in claim 4, also comprising a movable rear paper restraint (17), said first region (17b) and said inclined region (17a) being integral with said rear paper restraint.

Inventors: FLORES ARMANDO VILLAREAL, GETTELFINGER DARIN MICHAEL, RUSH EDWARD ALAN, WILLIAMS SCOTT STEPHEN, FLORES, ARMANDO VILLAREAL, GETTELFINGER, DARIN MICHAEL, RUSH, EDWARD ALAN, WILLIAMS, SCOTT STEPHEN
Applicants: LEXMARK INT INC, LEXMARK INTERNATIONAL, INC.
Application year: 1998
Main classification: B65H1
IPC codes: B65H1