| 摘要 |
PURPOSE:To output a copy image of invariably stable high quality by irradiating and scanning an original to length longer than requested copy size or the longest length of copying when the mixing ratio of a developer deviates from a specific value during copying operation. CONSTITUTION:Toner particles in the developer in a developer storage part 4 are consumed to cause a decrease in the mixing ratio to magnetic particles with time and the degree of the decrease is detected by a sensor 15, so that the detection information is inputted to a control circuit. When the degree of the decrease reaches a specific permissible lower limit, toner supply members 61 and 62 in a toner storage part 3 are rotated with the detection signal, thereby supplying the toner in the toner storage part 3 into the developer storage part 4 successively from a toner supply port 16. The original is irradiated and scanned to loner than the necessary copy size or the longest length of copying to agitate and convey the developer sufficiently, and consequently toner is prevented from sticking on a photosensitive body surface during said period, thereby eliminating a waste of toner preferably. |
