| 摘要 |
PURPOSE:To develop an electrostatic latent image with high sharpness and good gradation using a one-component type developer, by changing an alternating electric field in a development gap in a specified manner to control jumping development. CONSTITUTION:An alternating electric field satisfying Vmax>VD>Vmin (where Vmax and Vmin are max. and min. voltages, and VD is potential on an image areas) is generated in the gap between an electrostatic image bearing plate and a toner bearing body, and at that time, a toner high in reversed quantity as compared with VD reversed by the electric field for transferring the toner intensified or weakened in accordance with the time lengths t1 and t2 is transferred. Then, the applied alternating voltage is gradually attenuated, as shown in Vmax=VD+¦Vth.r¦, where¦Vth.r¦is an absolute potential difference across the gap capable of retransferring the toner to the toner bearing body, until it comes to converge to the DC value. Thus permitting the toner to be prevented from backward transfer, and the image to be favorably developed, the nonimage areas to be prevented from toner attachment, development to be excuted with high sharpness and good gradation by jumping of a one-component type developer. |
