| 摘要 |
PURPOSE:To always make the quantity of toner proper, and to always obtain an excellent image by supplying and stopping the toner by a control means with signals outputted from a toner quantity detector after the detector classifies the toner quantity into a 1st quantity or more, an intermediate quantity between 1st and 2nd quantities, a 2nd quantity or less. CONSTITUTION:When there is sufficient toner in a developing box, the output, voltage from the toner quantity detector 11 is lower than that of the 1st reference voltage source 23 and comparators 21 and 22 do not output the signals. When the quantity of toner is decreased, the voltage from the detector 11 becomes higher than that of the voltage source 23 and the comparator 21 outputs the signal, then the toner is supplied from a hopper. And the operation is continued until the voltage from the detector 11 becomes lower than that of the voltage source 23. When the toner is decreased because the images for which large quantities of toner is consumed are continuously formed and the voltage from the detector 11 becomes higher than that of a 2nd reference voltage source 24, the supply of the toner is continued until the voltage from the detector 11 becomes lower than that of the voltage source 23 even if image formation is completed. And the image formation is stopped during the supply of the toner. Thus, the toner quantity is always made proper and the excellent images can be obtained. |
