| 摘要 |
PURPOSE:To obtain a satisfactory image by means of transfer by optimally controlling transfer conditions for a toner image. CONSTITUTION:A test patch is formed on a photosensitive drum 1. The amount of toner charge before the transfer is detected by measuring by an ammeter 40 the amount of current which flows in a transfer brush 37 at the time of the transfer. Test patch transfer efficiency is detected by detecting the concentration of the toner on the photosensitive drum 1 before the transfer and the concentration of the residual toner after the transfer, by means of optical sensors 31 and 32, respectively. The detected amount of toner charge is compared with the optimum value. When the amount is not equal to the optimum value, the amount of toner charge before the transfer of the toner image is controlled by a pretransfer electrifier 39. When the amount is proper but the transfer efficiency is not proper, an electric field for the transfer with the brush 37 is controlled. Therefore, the transfer conditions can be optimally controlled and a satisfactory image can be obtained by the transfer. |
