| 摘要 |
PURPOSE:To economically exchange a toner cartridge by precisely displaying the exchanging time of the toner cartridge even when the residual quantity of toner in the toner cartridge becomes equal to or under the detecting ability of a toner sensor. CONSTITUTION:When the residual quantity of the toner in the toner cartridge 1 is equal to or over the prescribed quantity, the existence of the toner is decided based on the detection of the toner sensor 2(201). When the residual quantity of the toner becomes equal to or under the prescribed quantity, the existence of the toner is indirectly decided based on the number of recorded sheets or the like (202). Based on this decision, the exchanging time of the cartridge 1 is displayed. Thus, even when the residual quantity of the toner becomes equal to or under the detecting ability of the sensor 2, the exchanging time of the cartridge 1 is precisely displayed. |
