Sheet feeding or delivering – Feeding – By means to convey sheet
Patent
1997-03-12
1999-09-07
Terrell, William E.
Sheet feeding or delivering
Feeding
By means to convey sheet
B65H 502
Patent
active
059474718
DESCRIPTION:
BRIEF SUMMARY
TEXT OF THE DESCRIPTION
1. Field of the Invention
The present invention relates to a device for equipment for the handling of documents such as, for example, printers, photocopiers, facsimile machines, accounting machines, etc., for aligning the document (such as, for example, a sheet of paper, a form, a magnetic card, a cheque, a bank passbook, etc.) against a movable stop and subsequently for feeding it in the direction of a document processing station (such as, for example, an impact printing station, an ink jet printing station, a thermal printing station, an optical or magnetic reading station, an OCR reading/writing station, an MICR reading/writing station, etc.).
2. Related Technological Art
Devices such as the above are known in the current art, generally comprised for example by a couple of shafts, set in rotation by a motor through gearwheels or timing belts, one of which (the delivery roller) bearing a series of delivery rollers having a high coefficient of friction, and the other (the back-up roller) bearing a corresponding series of counter-rollers. A load is applied between the rollers and counter-rollers, by a spring for example, so that the document inserted between the delivery rollers and back-up counter-rollers is gripped between the afore-mentioned and fed by the frictional force developed by the surface of the delivery roller pressed by the spring-generated load against one face of the document, until it comes to rest against a stop.
The stop normally has the dual purpose of registering the document, namely of establishing a certain geometrical or temporal correspondence between the document position and position of the following document processing station (in order to set correct printing start position in phase with an exact reference on the document for example), and that of aligning the document, namely of making the front leading edge of the document parallel to the working direction of the document processing station (in order to obtain alignment of the document with respect to the scanning position of a printhead, for example).
The need for the adjusting and aligning operations is due to the fact that the above-mentioned equipment permits insertion of documents by the operator without any binding orientation requirements so as to simplify the method of use and reduce the time spent by the operator in handling the document.
On closer examination of the document alignment and feeding operations, it will be noticed that, whereas the latter type operation requires a high frictional force (which depends on the load and on the coefficient of friction) between the document and the surface of both the delivery and backup rollers for delivery to be effected without slippage, in document alignment there is a conflicting requirement. In fact, if the leading end of the document is not parallel to the stop, the whole document will have to effect a rotation around the first corner to touch the stop, a rotation which implies slippage of the document with respect to both the delivery and backup rollers and which is easier to effect the lower the value of the frictional force referred to above.
A method known in the art for solving these conflicting requirements is that described, for example, in the U.S. Pat. application Ser. No. 5,192,151 filed by Mattila, wherein a device for feeding a document comprises a first shaft equipped with a plurality of delivery rollers, touching the underside of the document, and a second shaft equipped with a corresponding plurality of backup counter-rollers, for keeping the document pressed against the delivery rollers with a determined load.
The pressure of each of the backup counter-rollers against the corresponding delivery roller is provided by two separate helical springs, one of which more rigid than the other, mounted on a supporting mechanism on each of the backup rollers; the device also comprises a lifting mechanism by means of which action may be taken on the supporting mechanism to selectively release the more rigid spring, so that two different val
REFERENCES:
patent: 2446211 (1948-08-01), Clark
patent: 3870293 (1975-03-01), Simeth
patent: 4470591 (1984-09-01), Acquaviva
patent: 5192151 (1993-03-01), Mattila
Bower Kenneth W.
Ing. C. Olivetti & C. S.p.A.
Terrell William E.
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