| 摘要 |
PURPOSE:To detect efficiently and exactly a toner concentration, to reduce a cost, and to make a device compact by executing a control so that a toner concn. in a developer becomes normal, basing on a picture signal. CONSTITUTION:A data is sent to a printer control part 11 and a laser scanning unit 12 from a printer interface 10. A pulse corresponding to a recording picture data is sent to a density control circuit 20 from the control part 11. The circuit 20 counts the number of pulses of this recording picture data, and calculates a consumed toner quantity from external information of print density setting, etc. When this quantity is detected, a toner supply quantity and a replenishing timing are derived. In case a contained capacity of a developer is large, a response of a toner concn. variation against a toner consumption is slow. Accordingly, it will do that a toner is replenished intermittently. A clutch 22 is driven through a clutch driving circuit 21. The clutch 22 is provided on a power transfer system 24, and replenishes a toner intermittently. |
