Sheet feeding or delivering – Feeding – By means to convey sheet
Reexamination Certificate
1999-06-10
2001-07-17
Skaggs, H. Grant (Department: 3651)
Sheet feeding or delivering
Feeding
By means to convey sheet
Reexamination Certificate
active
06260844
ABSTRACT:
FIELD OF THE INVENTION
The invention is directed to a device for conveying sheet-shaped material.
BACKGROUND OF THE INVENTION
Such a device is utilized, for example, in a single-sheet printer in order to convey single sheets of paper from one processing station to a next processing station. More recent printers require a plurality of such conveyor devices, so that the demand for high operating dependability is made of these. It can occur in traditional conveyor devices that, given imprecise guidance of the leading edges, of the trailing edges and of the side edges of a single sheet, a corner of the single sheet can be bent over and the corner that has been bent over, what is referred to as a “dog ear”, is fixed in the fashion of an ironing procedure due to the transport of the roller and counter-pressure roller lying opposite one another. Such a bent-over corner leads to a reject or can lead to a paper jam in the printer over the course of the further conveying path. It is therefore desirable to increase the operating dependability of such a conveyor device.
U.S. Pat. No. 5,040,781 discloses a device for conveying sheet material that is not flat, for example envelopes. The counter-pressure roller of this device has channel-shaped recessed in which the longitudinal edges of the envelope proceed. An obliquely guided envelope thus does not cause a conveying jam.
German AS 22 55 920 discloses a device for conveying card-shaped data carriers. The device has a driven roller that has a free-running counter-pressure roller residing opposite it. The data carriers are conveyed in the conveying nip between the two rollers.
DE-A 39 30 737 discloses a paper conveying means for printer devices, whereby paper is conveyed in the conveying nip between a driven roller and a counter-pressure roller that is likewise driven. The roller and the counter-pressure roller have recesses into which guide plates that supply the sheet-shaped material to the generated surfaces of the roller and the counter-pressure roller project.
Patent Abstracts of Japan, vol. 016, No. 195 (M-1246), May 12, 1992 and JP-A-04 028640 (Canon, Inc.), Jan. 31, 1992, disclose a paper guide unit wherein a counter-pressure roller has channel-shaped recesses into which tongues of a pressure plate engage. During operation, a single sheet is conveyed along the circumference of a conveyor roller in the conveying nip between conveyor roller and the pressure plate. The tongues engaging into the channel-shaped recesses of the counter-pressure roller guide the single sheet to the circumferential surface of the counter-pressure roller.
U.S. Pat. No. 3,957,366 discloses a paper delivery means wherein conveyor rollers residing opposite one another contain channel-shaped recesses.
Nose-shaped sections that are bent off at their ends and that have two operating positions project into these recesses. In the one operating position, the bent-off ends serve as detents that hold the single sheet at the front end edge, so that it arcs up given continued conveying. In the other operating position, the sections are lifted so that they release the single sheet and it is further-conveyed by the conveying nip formed by the rollers. The nose-shaped sections serve for aligning the single sheet, so that, after being supplied slanting, it can be further-conveyed with correctly aligned end edge.
U.S. Pat. No. 5,147,274 discloses an alignment means for sheet material. The sheet material is conveyed between rollers residing opposite one another. The longitudinal edges of the sheet material run freely between roller elements.
Therefore, there is a need for a device for conveying sheet-shaped material that works disturbance-free with high dependability.
SUMMARY OF THE INVENTION
The above need is satisfied by the present invention, wherein the guide plate engages into the channel-shaped recess. The individual sheets are thus reliably supplied to the generated surface of the roller or, respectively, of the counter-pressure roller. A tilting of the leading edges of the single sheet or of the lateral edges is largely precluded.
In one exemplary embodiment of the invention, at least one longitudinal edge runs in the channel-shaped recess. The corners of longitudinal edges of a sheet-shaped material, namely, can present problems during conveying since they can easily yield and be bent over when striking against counter-surfaces. The embodiment then provides that such longitudinal edges remain reserved from the pressure of the roller and of the counter-roller, i.e. run loosely along during conveying. Accordingly, no force that can effect a bending of the corners or of the edges can attack at such longitudinal edges. Consequently, the conveying of sheet-shaped material becomes more dependable then hitherto and ensues malfunction-free. Even if a plurality of conveyor devices of the invention are utilized in a single printer, the probability of outage due to conveying malfunctions is hardly increased since a faulty folding at the longitudinal edges cannot occur.
The shape of the recess provided in the invention can be rectangular, quadratic, semi-circular. The recess proceeds along the circumference of the respective roller. The recess or, respectively, the recesses can only be arranged on one roller, for example on the driven roller or on the counter-pressure roller. However, it is also possible to provide recesses on both rollers, whereby one preferably avoids having two recesses residing directly opposite one another.
The appertaining roller preferably has recesses at the locations at which longitudinal edges of single sheets of different width and formats proceed. What is thereby achieved is that it is also assured given a change in format that the longitudinal edges of the respective single sheets proceed within recesses and are conveyed merely force-free.
According to one embodiment of the invention, a paper running channel is formed by guide plates at at least one side of the conveying nip, these guide plates opening tunnel-shape in the direction of the conveying nip. The guide plates have salient sections that at least partially engage into the recess or, respectively, the recesses.
Given this type of arrangement of the guide plates, it is assured that a sheet of the sheet-shaped material is reliably supplied to the conveying nip between the roller and the counter-pressure roller or, respectively, is discharged therefrom without the leading edge or, respectively, the trailing edge of the sheet-shaped material being greatly bent down.
In an embodiment, the present invention provides a device for conveying sheets of material. The device comprises a cylindrical driven roller disposed opposite a cylindrical free wheeling counter-pressure roller. The driven roller and the counter-pressure roller are capable of engaging one another to form a conveying nip disposed therebetween. The counter-pressure roller comprises at least one circumferential channel-shaped recess. The driven roller comprises at least one circumferential channel-shaped recess. The at least one recess of the counter-pressure roller is aligned with the at least one recess of the driven roller. The device further comprises first and second parallel and opposing guide plates disposed on opposing sides of the nip. The guide plates define a channel for delivering the sheets of material to the nip. The first guide plate extends into the recess of the counter-pressure roller and the second guide plate extends into the recess of the driven roller. The first guide plate is pivotally mounted to the device and capable of being pivoted away from the driven roller.
In an embodiment, the guide plates are flared outward away from each other at the nip to thereby define a wider channel at the nip.
In an embodiment, the driven roller comprises two recesses disposed on opposing sides of a wider driving section that engages the counter-pressure roller. The second guide plate comprises a window-like aperture for at least partially accommodating the driving section of the driven roller. The second guide plate further compri
Naeser Helmut
Oberhoffner Gerhard
Pardubitzki Richard
Oce Printing Systems GmbH
Schiff & Hardin & Waite
Skaggs H. Grant
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