Xerox Corporation

John Maksymiak

Lawrence M Hart

Daniel S Hoffman

Ronald T Sosinski

Chi-Chang Lu

A buckle adjust procedure that automatically adjusts the amount of buckle introduced into copy sheets. The buckle adjust procedure includes the measurement of the time period for the trail edge of a first set of buckled copy sheets at the registration station to pass under a pre-registration switch. A second measurement is made of a time period for the trail edge of a second set of unbuckled copy sheets to pass under the pre-registration switch. The two time periods are compared and if the difference exceeds an acceptable range, an automatic adjustment is made to the amount of buckle introduced into copy sheets. The amount of buckle is determined by the time period that the copy sheets are driven into braked registration rolls.

Automatic buckle adjust

In touchdown-type development systems used in xerographic apparatus, an arrangement produces ambipolar development of the latent image. The arrangement utilizes only changes in electric potential in various portions of the development process to effect a polarity change from positive-to-positive (direct) development to reversal development and vice versa.

Touchdown ambipolar development

The self-stripping action of a copy sheet from an imaging suface after transfer in electrostatographic copying is substantially increased by slightly curving the imaging surface transverse their mutual direction of movement to provide a slight corresponding crown in the copy sheet on the imaging surface at the stripping area where the imaging surface is curved away from the path of the copy sheet in their direction of movement. Examples of the imaging surface are a substantially cylindrical photoreceptor surface with a uniform slight continuous crown, or a flexible belt slightly deformed over a crowned support roller.

Sheet stripping from imaging surface

A biased roller electrostatographic image transfer system in which the diameter of a resilient bias transfer roll is slightly larger at its outer end areas in comparison to its central copy sheet engaging area, so that the majority of the roll loading pressure is absorbed by these larger diameter end steps, which roll directly against the imaging surface outside of the copy area, and so that a relatively lower roll pressure is provided against the copy sheet in the operating nip. This reduction in the mechanical pressure in the transfer nip can provide lower 'hollow character' transfer defects, yet allows a sufficiently high roller loading force to prevent roll bounce and vibration.

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Penfield, NY, United States of America

John Maksymiak