| 摘要 |
<p>PURPOSE:To prevent reduction in the property of carrying caused by a failure such as paper jamming, even if a transfer material is repeatedly used by setting a region where an image is formed with toner capable of vanishing on the transfer material. CONSTITUTION:A photosensor 11 as a stuck toner quantity detecting means, a developing device A using the color vanishing toner, a developing device B using normal toner, etc., are connected to a CPU 31. A control part 30 sets image forming widths K1, K2 and n in the cases the set image density is lower than 1, N2 and Nn respectively. Moreover, the quantity of the color vanishing toner stuck on the transfer material is detected by the photosensor 11, the average value of the output voltage is compared with previously set reference values L1, L2...Ln and the image forming widths H1, H2...Hn and Hmax of an original where the image can be formed with the color vanishing toner are set in accordance with the result of the comparison. At this time, the image forming widths K1, K2...n are set as a prescribed region except the leading and tailing edge parts of the transfer paper in its feeding direction.</p> |
