Canon Kabushiki Kaisha

Sumitoshi Sotome

Shinji Yamamoto

Tadashi Matsumoto

Yasumi Yoshida

Takashi Hiratsuka

Toshihiro Fukasaka

An image forming apparatus includes an image bearing member; a rotatable belt member; a rotatable supporting roller for stretching the belt member; and a steering roller controlled by motors for stretching the belt member and for moving the belt member in a widthwise direction by an inclining operation. A number of sensors detect the position of the belt member in the widthwise direction and produce an output, causing a first controller to change the amount of the inclining operation of the steering roller in order to counter the force moving the belt member in the widthwise direction. The output of the sensors also causes a second controller to change the amount of the inclining operation of the steering roller in short intervals to reduce the rapid positional deviation of the belt member attributable to the inclination of the steering roller.

Image forming apparatus with belt position control feature

An image forming apparatus includes a rotatable belt member; an image forming station; first and second detecting members for detecting widthwise positions of the belt member; first and second steering rollers for correcting the widthwise positions of the belt member by inclination; a control portion configured to control inclinations of the first and second steering rollers on the basis of an output of the first or second detecting member; a first executing portion configured to execute, in a period other than an image formation period, an operation in a correction mode of, in a state that the first steering roller is at a first reference inclination, controlling the second steering roller to correct a second reference inclination of the second steering roller; and a second executing portion configured to execute, in a period other than that of the correction mode operation, an operation in a control mode of controlling the first and second steering rollers on the basis of the first and second reference inclinations.

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Yachiyo, Japan

Sumitoshi Sotome