| 摘要 |
PURPOSE:To prevent developer from sticking to a non-image area by stepwise switching the bias voltage and the exposure on the boundary (vicinity) between an image area and the non-image area of an electrostatic latent image carrier by first and second control means. CONSTITUTION:An AC bias and a DC bias from an AC voltage soure 47 and a DC voltage source 48 constituting a developing bias source are superposed one over the other and are impressed to a developing sleeve 131 and a doctor blade 132. The DC bias is converted to a digital signal by a converter 50 and is sent to a CPU 41a by data of the input/output characteristic of the DC developing bias from a ROM 41b, and the DC bias voltage is controlled based on this signal. The output signal from a lamp control circuit 51 which controls a blank exposure lamp 40 is converted to a digital signal by a converter 52 and is sent to the CPU 41a by data of the input/output characteristic for lamp light quantity control from the ROM 41b, and the light quantity of the blank exposure lamp 40 is controlled based on this signal. |
