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. 31, 1976
Filed:
Jul. 03, 1974
Nachio Seko, Sagamihara, JA;
Hiroshi Hirose, Machida, JA;
Ricoh Co., Ltd., Tokyo, JA;
Abstract
In electrophotographic apparatus for producing positive copies of both positive and negative originals with toner of one polarity by establishing and developing an electrostatic latent image on a light-sensitive member that is precharged to a first polarity for positive originals and to the opposite polarity for negative originals, wherein means are provided for exposing the precharged member to an optical image of the original and for controlling the exposure by varying the amount of light used, a two-position changeover switch for reversing the operation of the exposure controller depending on whether the original is positive or negative. This changeover switch, and also a switch for reversing the charging polarity of means for precharging the light-sensitive member, may be controlled by photoelectric means for determining whether the original is positive or negative by sensing the optical density of a marginal portion provided on the original.