Optical scanning apparatus, optical writing apparatus, and image forming apparatus
First Claim
Patent Images
1. An optical scanning apparatus comprising:
- 2n (where n≧
1) light sources, each light source including m (where m≧
1) light emitting units;
a synchronization detecting unit that receives m×
n light beams from the light sources, scans a scanning surface by the light beams emitted by 2n light sources, and determines a write timing for writing to the scanning surface, the light beams being substantially symmetrical with respect to a sub-scanning cross-section that includes a rotational axis of an optical deflector;
a first scanning lens system and a second scanning lens system arranged on either side of the optical deflector and causing m light beams to perform imaging on the respective scanning surfaces, whereinsynchronization detection by the synchronization detecting unit is performed at one end of each scan line, andthe first scanning lens system and the second scanning lens system are arranged substantially symmetrically with reference to a line in a main scanning direction orthogonal to the rotational axis of the optical deflector, andthe scanning lens system includes a no-power portion in the main scanning direction, and the light beams guided to the synchronization detecting unit pass through the no-power portion.
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Accused Products
Abstract
F-theta lenses, included in scanning lens systems, are arranged on a main scanning plane facing an optical deflector and substantially linearly symmetrically on the main scanning plane with reference to a rotational center of the optical deflector. Each f-theta lens has a no-power portion in the main scanning direction. Synchronization-detecting light passes through the no-power portion of the f-theta lens, thus enabling reduction in color shift due to temperature variation in an image forming apparatus without increasing the cost and complexity in controlling color shift.
97 Citations
16 Claims
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1. An optical scanning apparatus comprising:
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2n (where n≧
1) light sources, each light source including m (where m≧
1) light emitting units;a synchronization detecting unit that receives m×
n light beams from the light sources, scans a scanning surface by the light beams emitted by 2n light sources, and determines a write timing for writing to the scanning surface, the light beams being substantially symmetrical with respect to a sub-scanning cross-section that includes a rotational axis of an optical deflector;a first scanning lens system and a second scanning lens system arranged on either side of the optical deflector and causing m light beams to perform imaging on the respective scanning surfaces, wherein synchronization detection by the synchronization detecting unit is performed at one end of each scan line, and the first scanning lens system and the second scanning lens system are arranged substantially symmetrically with reference to a line in a main scanning direction orthogonal to the rotational axis of the optical deflector, and the scanning lens system includes a no-power portion in the main scanning direction, and the light beams guided to the synchronization detecting unit pass through the no-power portion. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An optical scanning apparatus, comprising:
-
2n (where n≧
1) light sources, each light source including m (where m≧
1) light emitting units;a synchronization detecting unit that receives m×
n light beams from the light sources, scans a scanning surface by the light beams emitted by 2n light sources, and determines a write timing for writing to the scanning surface, the light beams being substantially symmetrical with respect to a sub-scanning cross-section that includes a rotational axis of an optical deflector; anda first scanning lens system and a second scanning lens system arranged on either side of the optical deflector and causing m light beams to perform imaging on the respective scanning surfaces, wherein synchronization detection by the synchronization detecting unit is performed at one end of each scan line, the first scanning lens system and the second scanning lens system are arranged substantially symmetrically with reference to a line in a main scanning direction orthogonal to the rotational axis of the optical deflector, and the synchronization-detecting light does not pass through the scanning lens system. - View Dependent Claims (9)
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10. An optical scanning apparatus, comprising:
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2n (where n≧
1) light sources, each light source including m (where m≧
1) light emitting units;a synchronization detecting unit that receives m×
n light beams from the light sources, scans a scanning surface by the light beams emitted by 2n light sources, and determines a write timing for writing to the scanning surface, the light beams being substantially symmetrical with respect to a sub-scanning cross-section that includes a rotational axis of an optical deflector; anda first scanning lens system and a second scanning lens system arranged on either side of the optical deflector and causing m light beams to perform imaging on the respective scanning surfaces, wherein synchronization detection by the synchronization detecting unit is performed at one end of each scan line, the first scanning lens system and the second scanning lens system are arranged substantially symmetrically with reference to a line in a main scanning direction orthogonal to the rotational axis of the optical deflector, and an opening is provided in the scanning lens system, and the synchronization-detecting light passes through the opening. - View Dependent Claims (11)
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12. An optical writing apparatus comprising:
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a plurality of optical scanning apparatuses, each optical scanning apparatus including, 2n (where n≧
1) light sources, each light source including m (where m≧
1) light emitting units;a synchronization detecting unit that receives m×
n light beams from the light sources, scans a scanning surface by the light beams emitted by 2n light sources, and determines a write timing for writing to the scanning surface, the light beams being substantially symmetrical with respect to a sub-scanning cross-section that includes a rotational axis of an optical deflector; anda first scanning lens system and a second scanning lens system arranged facing each other on either side of optical deflector and causing m light beams to perform imaging on the respective scanning surfaces, wherein synchronization detection by the synchronization detecting unit is performed at one end of each scan line, and the first scanning lens system and the second scanning lens system are arranged substantially symmetrically with reference to a line in a main scanning direction orthogonal to the rotational axis of the optical deflector, wherein synchronization-detecting light of only one optical scanning apparatus is detected, and write timings of the other optical scanning apparatuses is electrically estimated based on detection signals of detected synchronization-detecting light. - View Dependent Claims (13, 14, 15, 16)
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Specification