| 摘要 |
PURPOSE:To form an excellent image free from color shift, excellent in resolving power and having no density irregularity, in a color image forming apparatus constituted so as to obtain a multicolor image by superposing toner images obtained by developing the latent image formed on a belt-like photosensitive body two or more times, by accurately removing the shift of a writing position in a subscanning direction due to the fluctuations of the speed of the belt-like photosensitive body. CONSTITUTION:A pattern 1A is provided to the side end part of a photosensitive belt 1 and the optical sensor 23 for detecting the pattern 1A is provided to an apparatus main body at a predetermined position and an encoder 24 is provided to a polyhedral mirror driving motor 79 and the phase difference between the pattern detection signal S1 of the optical sensor 23 and the signal S2 outputted from the encoder 24 is detected and the rotational speed of a rotary polyhedral mirror 74 is adjusted on the basis of the phase difference corresponding to the fluctuations of the speed of the photosensitive belt to certainly prevent the shift of. |
