| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of installations of a synchronizing detection sensor by guiding a plurality of light beams to one synchronizing detection sensor, without expanding a lens size for introducing synchronizing beams in an optical scanner that is applied to a tandem type image forming apparatus. SOLUTION: In the case where a cylinder array-like lens 83 in Fig.(C) is used as an SOS lens for the synchronization detection of optical beams L in the main scanning direction, in comparison with the case where a regular array lens 530 in Fig.(A) is used as an SOS lens, four light beams L can be fully condensed in a narrow area. Consequently, if the optical path fluctuation of the light beams L is within a desired tolerance relative to the incident position to the lens (e.g., deviation in a subscanning direction is within±2.5 mm before the lens), the beams can be always kept in line with an SOS sensor 38. COPYRIGHT: (C)2005,JPO&NCIPI
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