Canon Kabushiki Kaisha

Cannon Kabushiki Kaisha

Masako Takahashi

Yoji Serizawa

Atsuya Takahashi

Hitoshi Machino

Koichi Otaka

Shirou Sakata

Nobuyuki Kinoshita

Koichi Ohtaka

An engine control unit of a printer engine checks he 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.

System for detecting the status of an image forming apparatus

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.

Image forming apparatus, apparatus for supplying image data to image

An image heating apparatus has a heating member for heating an image on a recording material, a temperature detecting element for detecting the temperature of the heating member, and an electric power supply controller for phase-controlling an alternating current supplied to the heating member in conformity with the detected temperature by the temperature detecting element. The alternating current supplied to the heating member differs in electric power supply starting phase angle in each half wave.

Image heating apparatus with control for phase control of alternating

It is an object of the present invention to provide an apparatus and method which allow a service engineer to accurately analyze the situation of a printer and specify a failure when he or she arrives at the place where the printer is installed. A computer predicts a failure from the status information of a printer, and transmits a test pattern corresponding to the failure to the printer via a controller. The computer then outputs an indication of print out. The service engineer can accurately analyze the failure because the test pattern has already been printed out upon occurrence of the failure.

Method of printing test pattern and apparatus for outputting test pattern

A semiconductor laser is caused to emit laser light continuously on a plurality of scanning lines prior to image formation in a laser printer. An electric current to be applied is controlled so that the detected light quantity from the semiconductor laser becomes equal to the desired light quantity. The light quantity detected during pulsed emission with the applied current is used as the desired light quantity for APC which is performed at a space between sheets when a non-image area is scanned. Alternatively, laser light is emitted on a plurality of lines before the start of printing when printing of multiple pages is to be performed in a laser beam printer, to perform light quantity control. Then, laser light is emitted during scanning of a nonimage area between pages, to perform light quantity control. When light quantity control is performed between sheets, a value obtained by correcting an error between the quantities of light in both types of light quantity control is set as the desired light quantity. Alternatively, laser light is emitted continuously on a plurality of scanning lines prior to image formation to perform light quantity control. Then, laser light is emitted only when laser is scanning a non-image area to perform light quantity control, thereby setting a current volume to be applied to the semiconductor laser during image formation.

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Yokohama, Japan

Masako Takahashi