GB2215313A

GB2215313A - Sheet stacking and guiding

Info

Publication number: GB2215313A
Application number: GB8801230A
Authority: GB
Inventors: Peter Jamieson Troup
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1988-01-20
Filing date: 1988-01-20
Publication date: 1989-09-20
Anticipated expiration: 2008-01-20
Also published as: GB8801230D0; GB2215313B

Abstract

Sheets (11) are fed to collecting tray (10) by feed means (12) adjacent an edge of the tray, and engaged by one or more sheet guidance members (13) extending downwardly into the sheet path and arranged so as to be lifted by the lead edge of sheets being fed into the tray. The or each sheet guidance member comprises a rigid arm pivotally mounted (14) at its end furthest from the tray. The rigid arm preferably comprises first, generally horizontal, portion (15) and a second portion (16) angled downwards. <IMAGE>

Description

Sheet Deliverv and Stacking Apparatus This invention relates to a sheet delivery and stacking apparatus. The apparatus is of the kind comprising a sheet collecting tray, sheet feed means adjacent an edge of the tray for delivering sheets into the tray, and one or more sheet guidance members extending downwardly into the sheet path to engage and guide sheets that have been fed by the sheet feed means. The sheet guidance members are arranged so as to be lifted by the lead edge of sheets being fed into the tray.

An apparatus of this kind is described in Xerox Disclosure Journal, volume 6, number 5, September/October 1981, pages 237-8. In this disciosure, document sheets are restacked in the document tray of a recirculating document handler. As the document sheets are fed by rollers into the tray, they deflect flexible finger stops upwards, so that the strips act downwardly on the sheets as the sheets are fed. After a sheet has left the feed rollers, its trailing edge is pushed down towards the tray by the flexible strips, thereby assisting the stacking and settling down of the sheet into the tray. Other sheet guidance and control devices are described in Xerox Disclosure Journal, voiume 10, number 5, September/October 1985, page 273, and in US-A-4 469 319.

The flexible finger strips outlined above, which are typically of Mylar (TM), suffer from the disadvantage that they exert relatively little control on the paper, especially lightweight paper. They have the further disadvantage that they are prone to damage in use The present invention is intended to overcome these disadvantages, and accordingly provides a sheet delivery and stacking apparatus of the kind specified which is characterised in that the or each sheet guidance member comprises a rigid arm pivotally mounted at its end furthest from the tray.

The use of pivotted, rigid, sheet guidance members achieves much improved control over the paper sheets, giving rise to better settling and neater stacking of the sheets. The guidance members of the invention are also very robust.

A sheet delivery and stacking apparatus in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic cross sectional view of the apparatus when no sheet is being fed, and Figure 2 is a diagrammatic cross sectional view of the apparatus when a sheet is being fed.

Referring to the drawings, a recirculating document handler of a xerographic copying machine includes a document tray 10 into which documents 11 are stacked in preparation for automatic feeding, by the machine, over the platen of the machine. After each document has been fed from the bottom of the stack in the tray 10 and then moved over the platen for copying, it is returned for restacking into the tray 10 by means of a feeding arrangement such as feed rolls 12. Feed rolls 12 drive the document sheets as shown in Figure 2, over the top of the tray 10 so that when the sheet leaves the nip of feed rolls 12, it settles down into the tray 10, on top of any sheets already in the tray.

In order to improve the stacking and settling characteristics of the arrangement, one or more sheet guidance members 13 are provided, pivotally mounted about pivot axis 14 close to, and in front of, above, or behind, in the sheet feed direction, the feed rolls 12. The guidance member includes a generally flat portion 15 extending away from the pivot, and a down curved end portion 16. A directional rib 17 on the underside of the guidance member provides a smooth curved path to sheets which engage the underside of the guidance member, giving directional guidance to the sheets, as well as adding strength to the member.

A short angled portion 18 on the opposite side of the pivot from the flat portion 15 may be provided to prevent unwanted movement of the sheet guidance member 13, for example on lifting a cover of the document handler.

In a preferred form of the guidance member 13, it is moulded from plastics material, and is about 10 mm wide (measured in the direction of the pivot axis) and about 1.5 mm thick (through portions 15 and 16). The Slength dimension, from the pivot axis to the end of portion 16, measured parallel with the flat portion 15, is about 40 mm, and the perpendicular, Xheight, dimension, from the plane of the portion 15 to the tip of portion 16, is about 22 mm. The preferred weight is about 2.3 g.

In use of the apparatus of the invention, when no document sheet is being fed the guidance member 13 rests in its lower position, as shown in Figure 1, with the lower tip of portion 16 resting against the rear wall 19 of the tray 10. When a document sheet 11 is fed by feed rollers 12, the leading edge of the sheet engages the underside of the guidance member 13 and pushes it up into the position shown in Figure 2. Once the sheet has left the rollers 12, and continues to move to the right under its own momentum, the weight of the guidance member 13 acts downwardly on the trailing edge region of the sheet, retarding the forward motion of the sheet, and gently pushing it downwards so that the trailing edge settles down against the rear wall 19 of the tray. This enables a neat stack to be formed, which is easier for both the operator and the machine to handle than an untidy stack.

Claims

Claims:

1. Sheet delivery and stacking apparatus comprising a sheet collecting tray, sheet feed means adjacent an edge of the tray for delivering sheets into the tray, and one or more sheet guidance members extending downwardly into the sheet path to engage and guide sheets that have been fed by the sheet feed means1 and arranged so as to be lifted by the lead edge of sheets being fed into the tray, characterised in that the or each sheet guidance member comprises a rigid arm pivotally mounted at its end furthest from the tray.

2. The apparatus of claim 1 wherein said rigid arm is generally down curved in the sheet feed direction.

3. The apparatus of claim 2 wherein the rigid arm comprises a first, generally horizontal, portion and a second portion angled downwards.

4. The apparatus of claim 2 or claim 3 including a downwardly protruding rib on the underside of said arm, defining a smooth, curved, path for a sheet engaging the underside of the arm.

S. The apparatus of any one of claims 2 to 4 wherein, in the inactive condition, the forward end of the arm, remote from the pivot, engages the rear wall of the tray.