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:
Aug. 17, 1993
Filed:
Sep. 24, 1991
Applicant:
Inventor:
Yasuro Hori, Katsuta, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03G / ;
U.S. Cl.
CPC ...
355246 ; 355208 ; 355209 ; 430120 ;
Abstract
An electrophotographic printing apparatus includes a developing device which uses developer including toner and carrier particles. The quantity of electrical charges on the developer is measured and the developer is charged to a constant charge level in accordance with the result of the measurement. Accordingly, the developing density can be stabilized and the service life of the developer can be lengthened and predicted. A computer provides automatic processing to control the quantity of electric charges on the developer.