| 摘要 |
PURPOSE:To grasp accurately the remainder of a toner to replace a process cartridge at an optimum time by correcting exposure time information in accordance with the variance of toner consumption and generating a replacement signal on a basis of the correction time accumulated value. CONSTITUTION:A counter 3 is started by a modulator 1 to count clock pulses, and the exposure time of a photosensitive drum 101 is determined. This calculated value is corrected in accordance with the variance of toner consumption by a controller 6 which controls the laser light intensity from a laser 2 which is a factor of the variance of toner consumption. The correction counted value is accumulated, and the total of the corrected exposure time is stored in a memory 4; and when stored contents reach a prescribed value, the replacement signal is outputted through a comparator 5 and the controller 6, and the replacement time is displayed on a display means 7. Thus, the toner consumption is measured accurately to grasp the toner remainder accurately, and a process cartridge 112 where the drum 101, a primary charger 104, a developing device 106, etc. are built into one body is replaced at the optimum time. The similar operation is possible when the non-exposure time is utilized. |
