| 摘要 |
PURPOSE:To change an image based on an intention by providing the titled device with an electrostatic charging amount stabilizing means for stabilizing the charging amount per unit weight of toner at the switching of a carrying speed. CONSTITUTION:An output signal from a toner concentration sensor 32 is compared with a threshold level based on resistors 34-36 by a comparator 37 and a muCPU 21 inputs an output signal from the comparator 37 as a toner feeding request signal S4 through an I/O interface 25. The muCPU 21 outputs a toner feeding signal S5 to a driver 40 to turn on/off a toner feeding clatch 41 and to control toner feeding and selects the outputs of an oscillator 29 to switch the rotation frequency of a developing motor 31. The values of toner concentration sensor outputs U6 are different as E1.7 and E2.3 in spite of the same toner concentration by changing the charging amount per toner unit weight on the basis of the switching of the rotational frequency of the developing motor and a toner concentration sensor output level switching signal S3 turns off a lead relay 33 to correct the threshold level so that the level E2.3 in the normal state is turned to E1.7. |
