| 摘要 |
PURPOSE:To reproduce a solid area irrespectively of adjustment in image density by controlling the quality of the solid image by the image quality parameter different from adjustment of the image density. CONSTITUTION:An operator selects a solid area button in the case of copying an original having much solid area, then a CPU reads out control parameters such as bias voltage, exposure, dark attenuation voltage and gap stored in a ROM and applies the respective control commands to an electrifier, exposing means and developing device. The operator pushes thereupon a start button, then a photosensitive body rotates and prescribed quantity of electric charge is applied from the electrifier to the photosensitive body in such a way that the surface of said body attains the dark attenuation potential. The original image is irradiated on the surface of the photosensitive body and an electrostatic latent image is formed. The clearance between the electrifying body and a developing roller is set at the prescribed bias voltage in the developing device by the control command from the CPU and therefore the toner is stuck to the latent image at the quantity meeting such conditions, by which the visible image is formed. The solid part is thus sharply copied at the adequate quantity of the toner and the image part except the solid part is copied with the bias voltage corresponding to the conventional image density. |
