| 摘要 |
PURPOSE:To improve copy quality and prolong the life of a toner supplementing member by adjusting the once supplementary amount of toner to a value suitable for consumption. CONSTITUTION:A CPU9 detects the starting point of development of each primary color to turn on a multiplexer 7, and receives toner density signals from respective oscillators 6Y, 6M and 6C on time division basis, one after another, to output a toner supplement signal when the density is lower than a set value. This toner supplement signal drives the toner supplementing member for a time T to supply a minimum unit amount of toner, and the toner supplement signal outputted during copying operation is counted simultaneously to measure its frequency of generation. If the toner consumption is very large, the counted value increases. Then when the counted value attains to ''3'', the operaton time of the toner supplementing member is extended double to 2T, and when the counted value increases up to ''5'', the operation time is set to 3T, i.e. full operation, thereby supplying toner suitably for the consumption. |
