Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
1998-07-20
2001-10-09
Grant, II, Jerome (Department: 2624)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C358S474000
Reexamination Certificate
active
06301021
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a multi-beam optical apparatus for guiding laser beams which are exited from a plurality of light sources onto targets and, in particular, a multi-beam optical apparatus for controlling write timings relative to respective targets by controlling the exiting timing of each laser beam, and an image forming apparatus equipped with the multi-beam optical apparatus.
Generally, as the multi-beam optical apparatus there is known a light exposure device incorporated into an image forming apparatus such as a color copying machine, etc. The light exposure device comprises a plurality of light sources exiting laser beams based on color-separated image signals, a plurality of mirrors and of lenses conducting laser beams which are exited from the respective laser beam sources onto the surfaces (hereinafter referred to simply as drum surfaces) of photosensitive drums prepared for respective colors, and a plurality of polygon mirrors provided correspondingly to the respective laser beam sources and allowing the laser beams which are to be conducted to the respective drum surfaces to be deflected along the directions (horizontal directions) of the rotation shafts of the respective rotation drums to scan the drum surfaces.
In the type of a light exposure device, in order to detect the timings of writing the respective laser beams in the horizontal scanning directions, portions of the laser beams reflected on the respective polygon mirrors are reflected to corresponding reflection mirrors, so that they are received by a corresponding number of light receiving elements. And the timings in which writings are effected by the respective laser beams are controlled based on the laser beams-received by the light receiving elements.
As understood from the above, in the light exposure device of the conventional color copier, it is necessary to, as a structure for detecting the timings of effecting writings by the respective laser beams in the horizontal direction, provide a plurality of reflection mirrors and of light receiving elements so as to correspond to the corresponding mirrors. For this reason, many more components parts are required for the light exposure device and, in addition, the manufacturing cost becomes high.
Further, due to the presence of these many component parts involved, it takes a lot of time to adjust the optical paths of the laser beams conducted to the respective component parts and also much time is required to assembly the light exposure device.
BRIEF SUMMARY OF THE INVENTION
It is accordingly the object of the present invention to provide a multi-beam optical apparatus capable of manufacturing a low-cost unit of simpler structure and readily and positively controlling optical paths of laser beams and an image forming apparatus equipped with the multi-beam optical apparatus.
According to the present invention, there is provided a multi-beam optical apparatus comprising:
a plurality of light sources for emitting laser beams;
scanning means for scanning image carrier means by deflecting the laser beams emitted from the light sources;
light receiving means for receiving one of the laser beams which are emitted from the light sources and scan the image carrier means through deflection;
sync signal generating means for generating a sync signal based on the light receiving means;
first control means for, in order to form predetermined pattern images on the image carrier means, enabling the laser beams to be emitted from the light sources in synchronism with the sync signal generated from the sync signal generating means;
detecting means for detecting amounts of shifts relative to pattern images; and
second control means for controlling the timings of emitting the laser beams from the light sources on the basis of a result of detection made by the detecting means.
According to the present invention, there is further provided a multi-beam optical apparatus comprising:
a plurality of light sources for emitting laser beams;
scanning means for scanning a plurality of image carriers provided correspondingly to the light sources by deflecting the laser beams emitted from these light sources;
light receiving means for receiving one of the laser beams which are emitted from the light sources and scan the image carriers through deflection;
sync signal generating means for generating a sync signal based on the laser beam received by the light receiving means;
first control means for, in order to form predetermined pattern images on the corresponding image carriers, enabling the laser beams to be emitted from the light sources in synchronism with the sync signal generated from the sync signal generating means;
detecting means for detecting amounts of shifts relative to pattern images; and
second control means for controlling timings of emitting the laser beams from the corresponding light sources on the basis of a result of detection made by the detecting means.
According to the present invention, there is still further provided an image forming apparatus comprising:
a plurality of light sources for emitting laser beams based on an image signal;
scanning means for scanning image carrier means by the laser beams emitted from the light sources to form latent images on the image carrier means;
developing means for supplying developing agents to the latent images to form developing agent images on the image carrier means;
transferring means for transferring the developing agent images developed by the developing means to a transfer medium;
fixing means for fixing the developing agent images which are transferred to the transfer medium;
light receiving means for receiving one of the laser beams which are emitted from the light sources and scanned by the scanning means;
sync signal generating means for generating a sync signal which are obtained based on the laser beam received by the light receiving means;
first control means for enabling the laser beams which are based on pattern signals to be emitted from the light sources in synchronism with the sync signal generated by the sync signal generating means, the pattern signals being initially prepared as predetermined pattern images to be formed on the image carrier means;
detecting means for detecting amounts of shifts relative to pattern images; and
second control means for controlling timings for emitting the laser beams from the light sources on the basis of a result of detection made by the detecting means.
According to the present invention, there is still further provided an image forming apparatus comprising:
a plurality of light sources for emitting laser beams based on an image signal;
scanning means for scanning image carriers corresponding to the light sources by deflecting the laser beams emitted from the light sources to form latent images on the image carriers;
developing means for supplying developing agents to corresponding latent images to form developing agent images on the image carriers;
conveying means, having a conveying surface running along the image carriers, for conveying a transfer medium on the conveying surface while holding the medium relative to the image carriers;
first transfer means for transferring a plurality of developing agent images which are developed by the developing means to the conveying medium in a registering relation;
fixing means for fixing, to the medium, developing agent images transferred by the first transfer means in the registering fashion;
light receiving means for receiving one of laser beams which are emitted from the light sources and scanned by the scanning means through deflection;
sync signal generating means for generating a sync signal based on the laser beam received by the receiving means;
first control means for enabling the laser beams which are based on the pattern signal to be emitted from the light sources in synchronism with the sync signal generated by the sync signal generating means, the pattern signal being initially prepared so as to form predetermined pattern images on the image carriers;
second transfer means f
Foley & Lardner
Grant II Jerome
Kabushiki Kaisha Toshiba
Worku Negussie
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