| 摘要 |
PURPOSE:To obtain a satisfactory image by means of transfer by optimally controlling transfer conditions for a toner image. CONSTITUTION:A pattern image of 16 density levels are formed on a photosensitive drum 1. The transfer efficiency of each density level is detected by detecting the toner density of the pattern image on the photosensitive drum 1 before transfer and the density of the residual toner after the transfer by means of optical sensors 31 and 32, respectively. A difference between the detected transfer efficiency of each density level and the transfer efficiency under the optimum transfer conditions is obtained. When an amount of toner charge is judged not to be a proper value based on that, the amount of toner charge before the transfer of the toner image is controlled by a pretransfer electrifier 39; when a transfer electric field is judged not to be a proper value, the transfer electric field by a transfer electrifier 7 is controlled. Therefore, the transfer conditions can be optimally controlled and a satisfactory image can be obtained by the transfer. |
