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:
Oct. 13, 1992
Filed:
Aug. 02, 1990
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A device for controlling the application of a bias for development in electrophotographic image forming equipment which forms a latent image on a photoconductive element and develops it by a magnetic brush formed by a dry two-component developer on a developing sleeve to which the bias is applied. A detector is located between the optics and the developing unit for detecting the passage of opposite ends of a charged area of the photoconductive element one by one. The bias is turned on and then turned off, each later than the detection of a particular edge of the charged area by a period of time in which the edge travels from a sensing position to a developing position. The bias applied to the developing sleeve is turned on at the time when the leading edge of the actually charged area of the photoconductive element arrives at the developing position, and it is turned off at the time when the trailing edge of such an area passes the developing position. Voltage is applied to the developing sleeve stepwise such that at least one of the rise and fall of the bias potential occurs in two or more steps.