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:
May. 25, 2004
Filed:
Sep. 29, 2000
Noriyoshi Chizawa, Shizuoka, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An image reading apparatus employing a white fluorescent lamp, such as a xenon lamp, as an illuminating unit reduces variations in RGB output level caused by differences in persistence characteristics of phosphors, and also reduces color blurs at document edges in a vertical scanning direction. The lamp is turned on a plurality of times within one storage time of a CCD line sensor, and a lamp-on phase is shifted 180 or 90 degrees for each storage cycle or for each reading line. The lamp is not turned on at a timing when charges are transferred from a photoelectric converting element of the line sensor. Furthermore, a time from the moment when the lamp turns on last within the storage time to the timing at which the charges are transferred is set to be longer than a shortest afterglow time (B or blue) of the fluorescent lamp.