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:
Feb. 01, 2000
Filed:
Feb. 20, 1996
Yoji Serizawa, Kawasaki, JP;
Masako Takahashi, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An engine control unit of a printer engine checks the status of each part of the printer, and if there is any change in the status, generates a predetermined representative status of changes and outputs a status change signal to a controller (RIP). The controller is informed of a change in the status by the status change signal, and reads the predetermined representative status to discriminate the changed status from unchanged statuses. In accordance with the discriminated status, the current status can be read. Accordingly, it is not necessary to periodically read the statuses, improving the efficiency of an image forming process. A status change informing control unit in the engine control unit sets a changing status bit of a basic status or status change signal and sends it to the controller, when there occurs a change in any data of a presence/absence and paper size of a paper sheet at a paper feeding port and a loading state of an optional paper feeder. The controller periodically monitors the basic status or status change signal. Only when the changing status bit becomes true, the controller requests the engine control unit to supply the status data representative of a presence/absence, paper size, or loading state of an optional paper feeder.