| 摘要 |
PROBLEM TO BE SOLVED: To form a picture with no magnification error even when an optical housing which contains and holds a rotating deflector and a synchronous detecting part is deformed due to thermal expansion by keeping detection timing of synchronized detection light with the synchronous detecting part constant and keeping a writing position of an electrostatic latent image on an image holding body with a scanning line constant. SOLUTION: At least a laser light source, the rotating deflector, a scanning optical system and the synchronous detecting parts 26, 27 are contained and held in the optical housing 28. The synchronous detecting parts 26, 27 are placed on positions where displacement directions of the synchronous detecting parts 26, 27 associated with deformation of the optical housing 28 due to thermal expansion exist on optical paths of the synchronized detection light "B" with respect to the synchronous detecting parts 26, 27 before the displacement. Thereby, even when the optical housing 28 is deformed due to thermal expansion, the detection timing of the synchronized detection light "B" with the synchronous detecting parts 26, 27 is kept constant, the writing position of the electrostatic latent image on the image holding body with the scanning line is kept constant and the picture with no magnification error is formed. COPYRIGHT: (C)2004,JPO&NCIPI
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