| 摘要 |
PURPOSE:To keep image density at a fixed value in a device for moving toner from a developing roll to a photosensitive drum to develop a latent image by changing the generating period of AC voltage to be impressed between the drum and roll. CONSTITUTION:The photosensitive drum 11 is stopped during the scanning period of laser beams 19, and after forming a latent image, rotated and oppositely arranged to the developing roll 21. The composite voltage between a bias DC voltage and an AC voltage is generated from a voltage impressing circuit 25 and toner is moved to the drum 11. Since the rotational speed of the drum 11 is changed by dot data, its driving pulse is inputted to a comparator 53, and when the value becomes equal to a previously set value, the AC voltage with the fixed voltage and frequency is impressed between the drum 11 and the roll 21 for a fixed period. Thus, the quantity of toner to be moved is controlled by changing the generating period of the AC voltage in accordance with the rotational speed of the drum 11, so that the image density can be kept at the fixed value.
|
