| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus whose dimensions is kept constant by using the same housing, even if an LD (laser diode) is changed, and which reduces the kinds of densities of an ND (neutral density) filter. SOLUTION: The ND filter 20, and a cylinder lens 22, which is held on a holder 32 capable of being positionally adjusted in the direction of an optical axis, are provided on a sub-chassis 26 which is fitted into a plurality of positioning parts 30, provided in a frame 24, by means of a positioning guide 28. Since a lens-barrel 15 for holding a CML (collimator lens) 17 becomes longer than a lens-barrel 14 when an LD 13 with a spreading angle smaller than that of an LD 12 is used, a position of a leading end of the lens-barrel 15 is shifted to the side of the ND filer 20 with respect to a position of a leading end of the lens-barrel 14. The ND filter 20 and the cylinder lens 22 are moved by distances A and B equal to a distance C from the leading end of the lens-barrel 14 to that of the lens-barrel 15, so that interference between the lens-barrel 15, and the ND filter 20 and the cylinder lens 22 can be avoided, and so that the amount of the adjustment of the cylinder lens 22 can be secured. COPYRIGHT: (C)2006,JPO&NCIPI
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