| 摘要 |
PURPOSE:To obtain an image without surface staining and the nonuniformity of a density, even in a latent image composed of a large number of fine latent images. CONSTITUTION:A developing bias voltage composed of the pulse voltage (VPULS) of the period TA of one cycle and the DC voltage of a period (VDC) TB is applied to a developing roller 41 at a prescribed cycle frequency (f). The frequency (f) is set to apply the VPULS to one dot of an electrostatic latent image at least once on a developing region. Moreover, the frequency (f) can be set so as to be the ratio V/d of the peripheral speed V of the photosensitive drum 1 to a dot pitch (d) or above or almost equal to the integral multiple of the ratio V/d according to the writing density of the electrostatic latent image and a change in the setting of a process speed, etc. |
