International Business Machines Corporation

Ben A Nilsson

Raymond A Daniels

Roger D Shepherd

Harvey R Markham

Roberta R Tanner

Robert C Brannan

Robert L Fey

James E Bierschbach

In an electrophotographic copier, adjustments are made to synchronize copy sheet gating optics start of scan, and document conveyor registration. The adjustment to the copy sheet gating is effected by making a copy with the optics assembly inactivated, determining the length of undeveloped area adjacent to the leading or trailing edge of the copy, and adjusting the start of scan as a function of the determined length. The start of scan of the optics assembly is effected by positioning a test master document with dark portions adjacent to its leading and trailing edges, making a copy of the test master document, determining the length of undeveloped area adjacent to the leading or trailing edge of the copy, and adjusting the start of scan as a function of the determined length. The adjustment of the document conveyor registration is effected by feeding the test master document to the document glass, making a copy of the test master document, determining the length of undeveloped area adjacent to the leading or trailing edge of the copy, and adjusting the document conveyor as a function of the determined length. The determining steps may be done by visual inspection or by an optical sensor. The adjusting may be done manually, either electronically or mechanically. In the alternative, the adjusting may be done automatically in response to the optical sensor.

Synchronizing electrostatic copy formation

Apparatus and method for accurately setting a gap between mating

An electrophotographic copier having a toner concentration control apparatus which periodically effects a toner-patch test cycle during which the optical density of toner deposited on a photoconductor test area is measured, as by light reflectance. A time period of copier non-use, exceeding a preset time period, or a copier on/off operation, referred to as critical events, results in a transient mode of copier operation which includes reduction of photoconductor charge magnitude during the next subsequent use, independent of the extent of the prior copier use history. During such subsequent use, the toner-patch test cycle is operable to effect closed-loop control of changing the photoconductor's charge magnitude back to its nominal working value. More specifically, so long as the results of a toner-patch test cycle indicate an acceptable toner density, the photoconductor charge magnitude is maintained at a lower than working level. As the results of the toner-patch test cycle periodically indicate lower than acceptable toner density, as by a high light reflectance off the test patch, the photconductor's charge magnitude is periodically increased until finally the working charge magnitude is reached. The results of the toner-patch test cycle are operable to add toner to the copier's developer only when the photoconductor's charge magnitude has been increased to at or near the working magnitude.

Charge density control for an electrostatic copier

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Boulder, CO, United States of America

Ben A Nilsson