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:
Apr. 02, 1996
Filed:
Oct. 28, 1994
Takao Umeda, Mito, JP;
Toru Miyasaka, Hitachi, JP;
Osamu Namikawa, Katsuta, JP;
Isamu Komatsu, Takahagi, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
Device and method for evaluating a defect of a photoconductive body in which the position and number of defects such as pinholes in the photoconductive body are detected. The defect evaluation device includes a charger, a photoconductive body moving mechanism, a surface potential sensor, a position sensor detecting the position of a cap member on the photoconductive body and an arithmetic operation unit and a diagnosing device. A rotating photoconductive drum is charged by the charger, and the charged surface potential of the drum is measured by the surface potential sensor. The measured position is determined by the position sensor. The measured values by the surface potential sensor is subjected to differentiation processing by the arithmetic operation unit to determine a differentiation value dV/dt of the surface potential V of the photoconductive body with respect to time t. The diagnosing device detects a position on the photoconductive body whose surface potential abruptly changes, from the dV/dt to thereby determine a fatal detect.