| 摘要 |
PURPOSE:To reduce the deviation of each image in a transfer paper conveying direction by forming the pattern image for measuring of every recording device on a transfer belt and measuring the width of the boundary of the pattern image from the width of a rectangular wave output from one sensor. CONSTITUTION:The transfer belt 21 is supported by a belt driving roller 24 and a follower roller 25 and moves in an A direction so as to convey transfer paper. A reflection type sensor 27 functioning as a pattern image detecting means is provided on an downstream side in a belt moving direction with respect to a photosensitive body 14. The pattern images developed out of the area of the transfer paper by the respective recording devices with a signal from a pattern image signal generating means are transferred to the transfer belt 21 respectively. The pattern images 28Bk, 28C, 28M and 28Y successively pass the sensor 27 with the movement of the belt and are detected by the sensor 27. Therefore, the positional deviation quantity of two patterns can be obtained by observing one wavelength with one sensor 27. Thus, accurate detection of the positional deviation with a few spatial and temporal errors can be accomplished. |
