Electrophotography – Document handling – Original
Reexamination Certificate
2002-03-20
2003-11-25
Tran, Hoan (Department: 2852)
Electrophotography
Document handling
Original
C399S369000
Reexamination Certificate
active
06654586
ABSTRACT:
Disclosed herein is a simple and low cost system for automatically resetting one or both side guides of a sheet stacking tray in coordination and correspondence with the positioning of the side guide(s) of a sheet input tray (of a document handler input tray or a print media sheet input tray) to accommodate changes in the sizes of the sheets being fed and stacked, and to reduce output stack sheet scattering, especially skewed sheets stacking.
In the specific disclosed embodiment, the lateral setting (repositioning) of the (existing) variable position side guide in the input tray of a document handler (DH) to the side(s) of a stack of input sheets automatically correspondingly resets a side guide of an underlying (or overlying) output stacking tray, to reduce output stack sheet scattering (skewed stacking). In this embodiment, this is accomplished by a simple direct mechanical integration of these respective side guides of the respective trays or bins. Any increase in UMC is very small in the disclosed embodiment, since no additional sensors, motors, or solenoids are required.
By way of background, heretofore, normally a sheet output stacking tray does not have any variable position side guides. A key reason is that resetting such guides in an output stacking tray to a proper position that would not interfere with the stacking of larger (wider) sheets without overlapping the side guides or stubbing on them, would be too likely to be overlooked when an operator changes the size of the input sheets. It would require the operator to remember an extra, non-intuitive operation.
In the embodiment herein, there is shown an method and apparatus for controlling and reducing lateral sheet scatter in the output stack for various paper sizes by paper guide(s) which move together with, and may be directly mechanically attached to, the feeder/input paper guide(s). Adjustment of the input tray side guides automatically results in a corresponding adjustment of the output tray guides positioning. This disclosed system is suitable for various document handlers for document imaging systems and/or printers or multifunction machines, especially where a sheet input and output tray are in close proximity and/or superposed. It may be used with either separate or integral input and output trays.
One example of a prior art document handler with an input tray with adjustable side guides, of the type in which the two side guides are linked by a rack and pinion mechanism to move toward or away from each other by the same amount, to provide centered sheet feeding, is shown in Xerox Corp. U.S. Pat. No. 5,946,527. Two of its figures are provided herein, labeled “Prior Art.”
The present system can provide improved sheet stacking at lower speeds as well as higher speeds. By way of further background, as sheet feeding and stacking is desired at higher rates of speed, for example, to provide the feeding and scanning of original documents at rates of 120 documents per minute, or the like, the difficulty in neatly restacking the sheets is greatly increased. This is due to various effects, increasing with the velocity and sequential rate of the sheets being ejected into the output tray. For example, normal size sheets being outputted at an exemplary 120 documents per minute sequential rate may have a velocity of about 5.4 cm/sec. This may even cause what is called “airplaning,” especially of sheets with curled lead edges. Sheets being ejected to stack tend to “float,” due to air trapped under a sheet. The ejected sheet tends to drop onto the top of the underlying sheets of the output stack relatively slowly due to the relatively small force provided by gravity, especially for lighter weight sheets, as compared to the resistance of the air under the sheet. A high stacking rate provides very little inter-document time for the sheet to settle neatly before the next sheet enters the output tray, and the incoming sheet may slide laterally relative to the preceding sheet, or even impact it. Also, heavier sheets have higher kinetic energy. Thus, without additional physical stacking assistance, sheets being stacked in an output tray at a high rate of speed tend to form an unacceptably scattered stack, especially if not lateral confined during their settling. The term “scattered” herein includes, but is not limited to, sheets being unacceptably skewed relative to one another and/or being unacceptably laterally displaced from one another, as compared to being neatly superposed.
As noted, manually operator adjusted output stacking side guides and end guides can reduce such sheet scattering, but this has a significant disadvantage in the prior art. Namely, every time the lateral size of the sheets being fed in from the input tray changes, the operator must remember to also reset the side guides of the output tray to the same sheet dimension, or risk sheet jams or other problems. Hence, as in the above-cited and other such patents, often no repositionable side guides at all are provided in the output stacking tray. Or, electromechanical lateral side edge and or end of stack tampers are provided, at additional cost and complexity.
In this particular patent they word “imaging system” is being used broadly to encompass various conventional or other image reading or image printing systems. For example, image reading systems include conventional CCD array imaging bars, such as used in various commercially available document scanners, digital copiers, facsimile machines, or multifunction devices. However, in this application the term “imaging system” is being more broadly used to also encompass various image printing systems, such as the print heads of inkjet printers, xerographic printers, or other conventional image printing systems. Since these, and various sheet feeders, are all well known per se, they need not be described herein. This term “imaging system” is being more broadly used herein because the present system is suitable for either the feeding, image capturing, and restacking of original documents; or the feeding, printing and stacking of blank sheets. In both cases, the same type of sheets may need to be handled. That is, both may involve feeding of varying dimensions of paper or plastic print media sheets into an apparatus and their stacking in a sheet stacking output tray. In both cases, sheet scatter problems can be encountered if the sheets are not properly laterally confined during restacking after ejection into an output stacking tray.
In the disclosed embodiment, the above and other problems are overcome by vertical side guides in the output tray, at least one of which automatically moves in coordination with the setting of the input tray document stack side guide(s). One or both input tray side guides may be conventionally set by the operator by moving them against the sides of a stack of input documents. In the disclosed system this also automatically resets output tray side guides surfaces to a corresponding position in which the inputted sheets will neatly output stack in the output tray between output tray side guides which are automatically set to that same lateral sheet dimension, thereby reducing the opportunity for those outputted sheets to settle randomly.
As shown and described in the disclosed embodiment, the side-guides of the output tray can even desirably be a simple integral extension or part of the input tray side guides, at little additional cost, without requiring any motors or sensors, and without requiring any operator resetting of these output tray side guides.
As disclosed herein, the vertical side guides of the input tray may be connected to one another through a conventional rack-and-pinion system, as illustrated in prior document handler patents, such the above-cited Xerox Corp. U.S. Pat. No. 5,946,527 (or others) and its corresponding
FIGS. 3 and 4
here labeled “Prior Art.” Thus, operator resetting of the sheet-retaining space between the two side guides of the input tray can be accomplished by operator movement of one of them. While fully compatible therewith, the present system is n
Eyngorn Jacob
Lyon Donald J.
Tran Hoan
Xerox Corporation
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