| 摘要 |
PROBLEM TO BE SOLVED: To suppress turbulence between an add number line and an even number line in an image in terms of an electrophotographic type image forming apparatus having a multi-beam optical system. SOLUTION: At a starting point of scanning of two laser beams emitted from two semiconductor laser devices, horizontal synchronism signals nBDa, nBDb of the beams are corrected in reference to a total average value Tθof intervals Ta(S) (S4, S5), Tb(S) of the horizontal synchronism signals nBDa, nBDb detected from each of the beams (S8, S9). Adjusting of output timings of image data nVDOa, nVDOb in an odd number line and an even number line is executed in accordance with the corrected horizontal synchronism signals (S10). Thus, the timings of image outputs are adjusted in an optical system, then it is possible to electrically correct variation in one rotation of a polygon motor in the optical system or variation in a response speed of a light receiving element by each one scanning (one horizontal scanning). |
