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. 06, 2006
Filed:
May. 21, 2002
Kazuhito Ohashi, Ibaraki, JP;
Kazuhito Ohashi, Ibaraki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
The object of this invention is to provide an image reading apparatus capable of greatly reducing generation of a black streak image caused by dust, dirt, or the like at a flow scanning position on a document glass table in flow scanning of reading a document image while moving the document sheet at a predetermined speed. To achieve this object, the CPU of the image reading apparatus performs dust detection processing of detecting dust on the document glass table by a dust detection circuit during a document nonreading period. The CPU executes dust correction processing based on the dust detection result during continuous document reading. During an interval between the end of a series of image reading JOBs and the next image reading JOB, the CPU performs dust avoidance processing of changing the flow scanning position to a position free from any dust on the document glass table. If dust is difficult to avoid, the CPU inhibits flow scanning and executes control of switching flow scanning to optical scanning document reading.