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. 16, 1979
Filed:
Mar. 28, 1978
Yoshiro Suzuki, Hachioji, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
An electrophotographic apparatus comprises an electrostatic charge retentive drum composed of a metal cylindrical body and a photosensitive or insulating charge retentive layer applied on the cylindrical body. A corona charger serves to homogeneously change the charge retentive layer, and an optical system projects an optical image of a document to be copied onto the charge retentive layer so as to form a latent image. The latent image is developed with toners into a toner image and transferred onto a paper. The toner image is fixed on the paper and the whole surface of the charge retentive layer is cleaned. The electrophotographic apparatus allows selective application of a transfer bias voltage to so as to prevent at least partially undesired charge from being deposited on the charge retentive layer. The transfer bias voltage is applied only when the paper exists in the transfer region. Undesired charge on a peripheral portion of the charge retentive layer can be erased either in photoelectric or electric manner. In the former case, a peripheral portion of the charge retentive layer having a given width is illuminated so as to discharge undesired charge through the cylindrical body. In the latter case, an electrically conductive erasing member is brought into contact with the peripheral portion of the charge retentive layer so as to discharge undesired charge through the erasing member. The invention is particularly preferable to be applied to such an electrophotographic apparatus in which the development and transfer steps are repeatedly effected for a single latent image once formed on the charge retentive layer so as to form a number of copies at a high speed.