Sheet set stacking system with reduced stubbing

Details Sheet set stacking system with reduced stubbing Sheet set stacking system with reduced stubbing

2001-07-02

2003-05-13

Hirshfeld, Andrew H. (Department: 2854)

Typewriting machines

Sheet or web

For feeding sheet from stack or pack holder

C400S624000, C270S058110, C270S058130

Reexamination Certificate

active

06561709

ABSTRACT:

Disclosed in the embodiment herein is an improved but very simple and low cost system for the stacking ejection of sets of sheets onto a stack of sheets, with reduced tendencies for stubbing or snagging in doing so, by automatic lifting up of the stapled or other problem-portion of the set being ejected above the stack during the ejection of that set onto the stack. As further disclosed in this embodiment, this can desirably be done without requiring a separate drive system by utilizing and converting the existing set ejection system motion to provide a dual mode, dual direction, set ejection system.
By way of background, although the disclosed embodiment is shown in the compact set stacking output system of a “disk stacker”, it is applicable to various other sheet stacking systems. It is especially of interest for overcoming the “stubbing” problems of stapled sets being substantially horizontally ejected to be stacked on top of other stapled sets. It is a recognized problem that the staples or other projections can interfere with (cause “stubbing”) as that set is being pushed out over the previously stacked set.
This “stubbing” problem is of particular concern in compact combined set compiling and stacking systems, in which the sets are stacked on a stack elevator which maintains the top of the stack at about the same level as the bottom of the set being compiled and stapled. That is, roughly level with, rather than much lower than, the compiler surface. That is done so as to partially support the overhanging (projecting) portion of the set being stapled. That allows the set compiling area to be smaller than the sheet dimensions in the process direction. Such known compact combined compiling and stacking systems desirably partially combine the horizontal space that would be required by a separate compiler and separate stacker.
Current methods to combat this problem include the use of a separate solenoid actuated and spring loaded “set separator” arm mechanism inserted out over part of the previously ejected and stacked set, then retracted for the next set, e.g., Minolta Co., Ltd., U.S. Pat. No. 6,244,583 B1, issued Jun. 12, 2001. That system has a relatively high cost, several moving parts, space requirements, is exposed to damage, and requires additional software to control it. Furthermore, as multiple stapled sets accumulate on top of one another in the output stack the overlying staples thereof tend to cause those staple areas to stick up or rise higher that the rest of the stack.
Other efforts to solve this stubbing problem in finisher compiled, stapled and stacked sets systems have included designs for different stacking tray angles, and/or stacking tray corner cut-outs (stack unsupported areas), especially for finished sets which are only corner-stapled, as compared to plural edge stapled. While none of those designs are excluded from, or incompatible with, use with the present system, the disclosed system is believed to be far more effective for reducing the stubbing problem.
Disclosed in the embodiment herein is a simple and low cost dual mode system and mechanism, capable of utilizing the existing horizontal movement of a set ejection system, so as not to require any additional drive system, yet automatically lifting up the stubbing problem portion of the compiled set vertically relative to the prior stacked sets during the otherwise horizontal or downstream ejecting movement of the (stapled or unstapled) set. This simple yet effective system can then also automatically retract downwardly with the rearward retraction of the set ejector so as not to interfere with further compiling or stapling operations, such as the rotation and sheet stripping of a disk stacker compiling operation.
Yet, as also shown in the specific illustrated example, a relatively sophisticated stubbing prevention function can be accomplished using a simple foldable and un-foldable (hinged) plastic or metal member which forms an automatically raised and lowered ramp or guide for the sheet or set of sheets being ejected out onto the stack of sheets on the stacking surface.
That is, the disclosed embodiment shows that a dynamic ramp system to greatly reduce snubbing tendencies can be accomplished with a very simple, even one piece, device that utilizes the existing motion of the set ejecting mechanism of the finisher to perform its functions and timing. Reduced cost and improved reliability over prior systems are significant advantages.
Some examples of Xerox Corporation patents on disk stackers (noted above), and also providing some examples of compact (shared) set compiling, ejection and stacking systems (as described above), with or without set stapling, include Xerox Corp. U.S. Pat. Nos. 5,409,201; 5,409,202; 5,685,532; 5,642,876; 5,803,705; 5,692,740; 5,803,705, or 5,842,695. A different (non-disk) type of compact compiler-stapler-stacker is shown, for example, in Xerox Corp. U.S. Pat. No. 5,884,910.
A specific disclosed feature of the specific embodiment disclosed herein is to provide in a set fastening, ejecting, and stacking system for stacking in a stack of multiple printed sheets, at least some of which are sets of plural said printed sheets having one or more set fasteners in a fastening area of said printed sheets, wherein a said set of plural printed sheets with an area of one or more set is fasteners is ejected by a set ejector with a horizontal movement component to slide out over said stack of multiple printed sheets, the improvement comprising an automatic dynamic ramp system for temporarily lifting up with a vertical movement component said fastening area of said set with said set fasteners out of contact with said stack of multiple printed sheets while said set is being ejected by said set ejector with said horizontal movement component to slide out over said stack of multiple printed sheets to prevent snagging of said set fasteners with said stack of multiple printed sheets.
Further specific features disclosed in the embodiment herein, individually or in combination, include those wherein said automatic dynamic ramp system for temporarily lifting up said area of said set with said set fasteners is driven by engagement with said set ejector; and/or wherein said automatic dynamic ramp system for temporarily lifting up said area of said set with said set fasteners comprises a foldable member that is at least partially folded up vertically by said horizontal movement component of said set ejector; and/or wherein said automatic dynamic ramp system for temporarily lifting up said area of said set with said set fasteners comprises a hinged plate member that is at least partially folded up vertically about said hinge by engagement with said set ejector.
Unless otherwise defined in a claim, the terms “reproduction apparatus” or “printer” as used herein broadly encompasses various printers, copiers or multifunction machines or systems, xerographic or otherwise. Likewise, the term “sheet,” or “print media” herein refers to a usually flimsy physical sheet of paper, plastic, or other suitable physical substrate for printed images, whether precut or initially web fed. A “copy sheet” may be abbreviated as a “copy” or called a “hardcopy.” A “print job” is normally a set of related sheets, usually, but not necessarily one or more collated copy sets copied from a set of original document sheets or electronic document page images, from a particular user, or otherwise related. A “set” as used herein refers to whatever plurality or multiplicity of sheets have been selected to be compiled and are being ejected together for stacking. The terms “finisher” or “finishing” may broadly relate to various post-printing operations on printed sheets, which can include any of, or a combination of, set compiling, stapling, gluing, binding, hole punching, applying covers or inserts, trimming, output stacking, etc.
As to specific components of the subject apparatus or methods, or alternatives therefor, it will be appreciated that, as is normally the case, some such components are known per se in other apparatus or

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