PURPOSE: To provide a nonmagnetic one-component developing device capable of forming an optimum toner thin layer and further, preventing the generation of the image defect of a ghost, etc.
CONSTITUTION: The nonmagnetic one-component developing device is composed of a hopper 31, a developing roller 32, a regulating member 33, a toner supplying roller 34, etc. The developing roller 32 is a semiconductive elastic roller and has the application of -250V bias voltage by a power source 35. The toner supplying roller 34 is a semiconductive porous elastic roller made of foamed urethane sponge having 80-150 cells per inch, etc., and has the application of -500V bias voltage by a power source 36. In other words, the absolute value of the bias voltage (-500V) applied to the toner supplying roller 34 is larger than that of the bias voltage (-250V) applied to the developing roller 32 and the difference between the voltages is set within the range of 200V-500V.
TOSHIYUKI KOUICHI
ONO KUNINORI
CASIO COMPUTER CO LTD
Next Patent: DEVELOPING DEVICE