Title:
OPTICAL SCANNING METHOD
Document Type and Number:
Japanese Patent JPH02166415
Kind Code:
A
Abstract:
PURPOSE:To compensate curvature of field in a subscanning direction and to make a high-density optical scan by varying the length of the optical path between a 1st image formation optical system and a rotary polygon mirror by an optical path length varying device. CONSTITUTION:The optical path length varying device is arranged between the 1st image formation optical system 2 and rotary polygon mirror 3. The optical path length varying device consists of a fixed part 8a, a movable part 8f, and a driving part, and the fixed part 8a and movable part 8b are composed of combinations of roof prisms and/or roof mirrors. The movable part 8b of the optical path length varying device is displaced by a driving part by being driven by a piezoelectric element or magnetostrictive element according to the curvature of field in the subscanning direction by 2nd image formation systems 5 and 6 every time luminous flux is deflected, thereby making an optical scan while compensating the curvature of field in the subscanning direction. Therefore, the light source device 1 and 1st image formation optical system 2 may be fixed as they are and their position accuracy is held high. Consequently, the high-density optical scan is made excellently.
Inventors:
SUZUKI SEIZO
TAKANASHI KENICHI
TAKANASHI KENICHI
Application Number:
JP32165788A
Publication Date:
June 27, 1990
Filing Date:
December 20, 1988
Export Citation:
Assignee:
RICOH KK
International Classes:
G02B26/12; G02B26/10; (IPC1-7): G02B26/10
Attorney, Agent or Firm:
Toru Kabayama (1 person outside)
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