| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect the rotating speed, the deviation and the meandering of a belt with simple constitution. <P>SOLUTION: The image forming apparatus is equipped with: belt marks (11) arranged at equal intervals in the rotating direction of an endless belt (TB) on the surface of the belt (TB) and formed in the shape of a polygon having an inclined side, which is inclined to an axial direction; a mark reading sensor (SN1) having an image reading region of predetermined area and reading the belt marks (11); a mask (19) having an aperture part (19a) narrower than the image reading region; a belt rotating speed detection means detecting the rotating speed of the belt (TB) based on the passing time of the belt mark (11) read through the mask (19); and a belt deviation detection means detecting the deviation of the belt (TB) in the axial direction based on the time when the belt marks (11) are read through the mask (19) and the time when the intervals between the belt marks (11) are read therethrough. <P>COPYRIGHT: (C)2007,JPO&INPIT |
