| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the damage of a photoreceptor, to reduce a power consumption and to suppress the generation of ozone. SOLUTION: Toner images are sequentially transferred from photoreceptor units 13a, 13b, 13c and 13d to a paper 11 which is attracted and carried by a transfer belt 12 so as to form a color image. A toner patch for density correction is directly formed on the transfer belt 12. When the toner patch is formed, out of transfer/electrostatic charging devices 14a, 14b, 14c and 14d for outputting a transfer voltage, the devices positioned on the upstream side of the photoreceptor unit which is used for forming the toner patch in the carrying direction of the transfer belt 12 is shielded by a controller 17, and the device positioned on the downstream side is adjusted by the controller 17 so that the retransfer may become the minimum one. A transfer voltage at a toner patch forming position is adjusted so that the highest density can be obtained. The device is controlled in accordance with the detection results of a temperature sensor 18 and a humidity sensor 19. |
