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:
Mar. 08, 2005
Filed:
Feb. 12, 2003
Akihiko Hamamoto, Irvine, CA (US);
Akitoshi Yamada, Irvine, CA (US);
Hiromitsu Hirabayashi, Ivine, CA (US);
Akihiko Hamamoto, Irvine, CA (US);
Akitoshi Yamada, Irvine, CA (US);
Hiromitsu Hirabayashi, Ivine, CA (US);
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An ink jet printing apparatus which performs printing by using a print head. The print head has at least a predetermined number of nozzles to eject ink. The apparatus includes a first prefiring mechanism for causing the print head to perform a prefiring operation to eject ink from nozzles of the print head for maintaining printing quality after a first time interval during a printing operation. The apparatus also includes a driving mechanism for driving nozzles of the print head based on data to be printed, and a second prefiring mechanism for causing the print head to perform the prefiring operation in a case where a number of the nozzles to be driven is changed. Preferably, the apparatus further includes a shifting mechanism for causing the driving mechanism to drive the nozzles of the print head based on the first time interval during the printing operation so as to enhance a power of ejecting ink and continue the printing operation after the first time interval without performing the prefiring operation. The shifting mechanism also preferably delays the prefiring operation to a second time interval longer than the first time interval, and after the second time interval, the first prefiring mechanism causes the print head to perform the prefiring operation. In a case where the number of nozzles to be driven is changed within a time duration after the first time interval and during the second time interval, the second prefiring mechanism causes the print head to perform the prefiring operation.