International Business Machines Corporation

Dennis C Estabrooks

Jack Louis Zable

Nelson K Arter

William George Jackson

An electrophotographic apparatus and method are provided to reduce smearing on printed medium by reducing the toner pile height of printed lines and characters. Control is provided for establishing the amount of toner to be applied on a picture element (PEL) basis. This is accomplished by the creation of mask patterns that distinguish characters and lines from large patches to be printed, and by identifying PELs internal of characters boundary requiring exposure modulation during printing.

PQE for font vs. large dark patch

A document feeder for automatically inverting a duplexed original so that the second side may be copied. The inverting mechanism is a turnaround roll located at the exit of the copy station. The inverting mechanism cooperates with rollers located above the document glass for moving documents thereacross. The rollers are inclined at an angle to the direction of paper movement in order to position paper against a side reference edge. When receiving a document from the turnaround roll and moving it in the reverse direction, the inclination of the rollers is removed or altered to a minus angle. Alternatively, a second set of rollers, inclined at a minus angle, are brought into active use when documents are moved in the reverse direction.

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Longmont, CO, United States of America

Dennis C Estabrooks