The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 01, 1990
Filed:
Jan. 13, 1989
Peter R Watson, Stevenage, GB;
Xerox Corporation, Stamford, CT (US);
Abstract
An automatic or semi-automatic document feeder (12) for conveying documents sheets (17) into and away from an imaging position (18) on a platen (14) of a copier, incorporating a plurality of spaced-apart belts (30) moving between a white backing surface (26) and the platen. A vacuum source applies a partial vacuum to the inter-belt gaps (32) to hold a document sheet against the belts so that the document is conveyed with the movement of the belts. A major portion of the backing surface (26) lies in a datum plane. Discrete protrusions (56) which extend above the datum plane are formed integrally on the backing surface in pairs or rows, against which the belts ride to hold the belts in spaced relation to the datum plane. The spaces (57) between the protrusions provide openings so that a partial vacuum applied beneath the belts may extend into the inter-belt gaps. 'Show-through' and 'show-around' printing defects are thus substantially reduced because the backing surface can be entirely flat between the belts and the belts themselves require no apertures. Channels may be provided beneath the belts in the longitudinal direction thereof to ensure the application of uniform partial vacuum over the whole platen area.