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:
Jun. 05, 1990
Filed:
Mar. 11, 1988
E Neal Tompkins, Atlanta, GA (US);
Jack N Bartholmae, Duluth, GA (US);
Peter A Zuber, Norcross, GA (US);
Kirk W Charles, Atlanta, GA (US);
Colorocs Corporation, Norcross, GA (US);
Abstract
A transfer mechanism for a full color double transfer electrophotographic print engine. Relatively conductive developer materials having successively increasing triboelectric charge characteristics are used to develop sequential images. Conductive plates displaced away from the transfer station along the direction of travel of the transfer belt are used as one electrode for applying an electrostatic field at each transfer station. A parameter of the transfer mechanism is a bulk resistivity of the transfer belt in the range of 10.sup.7 to 10.sup.10 ohm-centimeters and a surface resistivity for the belt in the range of 10.sup.7 to 10.sup.10 ohms per square. A selectively operable compression roller, compressing paper and transfer belt against a rubberized idling roller at one of the transfer stations increase dwell time in the transfer station. The compression roller automatically falls to a cleaning station where it is rotated by another rotary member to clean it between transfers. The use of conductive developer materials also tends to eliminate halo problems common in color electrophotography.