Automatic document feeders for copying machines and method for

Abstract

An automatic document feeder installed on a copying machine. This document feeder is constructed such that one reversible motor provides the drive power for all of drive parts of the document feeder, that is, a document feeding part, a document conveying part and a document recovering part, thus substantially reducing the manufacturing cost of the feeder. The document conveyor belt, on which a document to be copied is closely laid, moves in the forward and reversed direction, thereby causing the document to be exactly set on a reference copying position of a contact glass of the copying machine and, in this respect, improving the operational efficiency of the automatic document feeder. The present invention also provides a control circuit for automatically controlling such an automatic document feeder. The circuit comprises a microprocessor useful for efficiently controlling the operations of the document feeder even in the case of feeding of documents having different sizes and in the case of addition of other operational functions to the document feeder. Furthermore, this document feeder is provided with a document separating belt, which selectively moves and closely contacts with a document separating roller, thus improving the document separating efficiency and lengthening the using life of the document feeding part.