| 摘要 |
PURPOSE:To maintain the toner concn. in the developer accurately within a permissible width at all times by setting the width of the control image of a black color installed before or behind an original imposing surface in the direction orthogonal to the moving direction of a photoreceptor. CONSTITUTION:The toner concn. is satisfactory if the toner pickup amount for the control latent image at the maximum quantity of image exposure light when said concn. is a lower limit Tmin. of a permissible width is below the toner pickup amount at the minimum quantity of image exposure light when said concn. is an upper limit Tmax. of the permissible width. The toner pickup amount fluctuates in accordance with the value of the potential difference VG between a control latent image potential VS and an effective developing bias potential VBE, that is, a control image width (l). Then, if the control image width (l) is determined from the equation II by the constant A satisfying the equation I, the toner concn. is maintained within the permissible width despite simultaneous employment of a control latent image replenishing system and a self-bias combination use system making combination use of an exposure control system. With such constitution, the toner concn. in the developer is maintained accurately within the permissible range at all times. |
