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:
Jun. 09, 1992
Filed:
Jan. 14, 1988
Toshio Honma, Kawasaki, JP;
Nobuo Matsuoka, Yokohama, JP;
Shizuo Hasegawa, Tokyo, JP;
Yasumichi Suzuki, Tokyo, JP;
Hiroshi Itagaki, Yokohama, JP;
Kenji Sasahara, Mitaka, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An image reading apparatus such as a color copying apparatus has a plurality of sensing CCD chips for converting an image of an object into an electrical signal, each sensing CCD chip having a plurality of sensing elements. The apparatus also has a circuit for converting the electrical signal into digital data. A first adjusting circuit is provided for conducting either an operation for obtaining level matching of the electrical signal converted by the sensing chips, or an operation for controlling the gain of the electrical signal converted by the sensing chips. The apparatus further has a second adjusting circuit for effecting compensation for fluctuation of characteristics of the sensing elements of the sensing chips, by making use of the digital data converted by the converting circuit, the second adjusting circuit being adapted for effecting the compensation on the basis of electrical signals which are produced as a result of conversion by the sensing chips from two objects having different levels of density from each other, such as white and black levels.