Image forming apparatus configured to scan and controlling method therefor
AssigneeBrother Kogyo Kabushiki Kaisha
InventorKazushi SHUMIYA
Life of this patent
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Abstract
An image forming apparatus includes a polygon mirror having a first mirror surface and a controller. The controller is configured to: acquire a detection interval corresponding to one rotation of a polygon mirror; start scanning exposure with a first beam deflected by the first mirror surface, in response to elapse of a first time period after a detection signal has been detected; and start scanning exposure with a second beam deflected by the first mirror surface, in response to elapse of a second time period after the detection signal has been detected. The second time period is calculated based on the detection interval.
Claims12
An image forming apparatus comprising:
- a first light source configured to emit a first beam;
- a second light source configured to emit a second beam;
- a polygon mirror configured to deflect the first beam and the second beam and having a first mirror surface;
- a motor configured to rotate the polygon mirror about a rotation axis;
- a first scanning optical system configured to focus the first beam deflected by the polygon mirror on a first photosensitive body, the first scanning optical system defining a scanning direction;
- an optical sensor disposed upstream of the first scanning optical system in the scanning direction and configured to detect the first beam deflected by the polygon mirror to output a detection signal in response to the detection;
- a second scanning optical system disposed opposite to the first scanning optical system with respect to the rotation axis and configured to focus the second beam deflected by the polygon mirror on a second photosensitive body;
- and
- a controller configured to perform:
- acquiring a detection interval of the detection signal during which the polygon mirror makes one rotation;
- in response to elapse of a first time period after the detection signal has been detected, starting scanning exposure with the first beam deflected by the first mirror surface;
- and
- in response to elapse of a second time period after the detection signal has been detected, starting scanning exposure with the second beam deflected by the first mirror surface, the second time period being calculated based on the detection interval.
A method for controlling an image forming apparatus,
- the image forming apparatus comprising:
- a first light source configured to emit a first beam;
- a second light source configured to emit a second beam;
- a polygon mirror configured to deflect the first beam and the second beam and having a first mirror surface;
- a motor configured to rotate the polygon mirror about a rotation axis;
- a first scanning optical system configured to focus the first beam deflected by the polygon mirror on a first photosensitive body, the first scanning optical system defining a scanning direction;
- an optical sensor disposed upstream of the first scanning optical system in the scanning direction and configured to detect the first beam deflected by the polygon mirror to output a detection signal in response to the detection;
- and
- a second scanning optical system disposed opposite to the first scanning optical system with respect to the rotation axis and configured to focus the second beam deflected by the polygon mirror on a second photosensitive body;
- and
- the method comprising:
- acquiring a detection interval of the detection signal during which the polygon mirror makes one rotation;
- in response to elapse of a first time period after the detection signal has been detected, starting scanning exposure with the first beam deflected by the first mirror surface;
- and
- in response to elapse of a second time period after the detection signal has been detected, starting scanning exposure with the second beam deflected by the first mirror surface, the second time period being calculated based on the detection interval.
Dependencies are inferred from the claim text.