| 摘要 |
PURPOSE:To appropriately detect the transfer amount of toner by constituting the transfer supporting body of respective color filters complementing respective colored toners, transferring the toner on its complement color filter and detecting the toner transfer amount from the intensity of transmitting light. CONSTITUTION:When a pattern made by a yellow toner is transferred on the filter FB in a yellow process, a controller 56 synchronizingly controls a photocoupler 24 to operate, and a light receiving element 24B converts the intensity of the light transmitting both a layer made of the yellow toner and the filter FB into an electric signal. It is amplified by an amplifier 52, converted into a digital signal VB1 by an A/D converter 54, and impression on a CPU 60. It reads contents VB1, R=VB1/VB0, and detects is as the transfer amount of the yellow toner. Then the CPU 60 reads out the reference value R0 of the ratio R stored in a ROM 64, compares it with the ratio R. If R>R0, the CPU 60 considers it that the yellow toner in a developing unit 14Y is likely to lack, and issues a signal showing the makeup of the yellow toner. |
