DEVELOPING DEVICE AND TONER CONCENTRATION CONTROL METHOD

PROBLEM TO BE SOLVED: To stabilize the image quality of a printed image by reducing variation in characteristics of a developer. SOLUTION: A developing device is provided with: a toner bottle 141 being a developer replenishing member; a bottle motor 142 being a replenishing member driving means; a developing roller 210; a first agitating screw 220; a second agitating screw 230; a toner sensor 240; a developing motor 401 being a developing member driving means; a control part (CPU) 1010; a developing member action time storing means (RAM) 1020; a replenishing member action time storing means (RAM) 1030; and a table data storing means (ROM) 1040. The control part 1010 refers to the table data stored to the table data storing part 1040 and compensates control voltage of a toner concentration detecting means by a compensation value corresponding to developing member action time stored to the developing member action time storing means 1020 and replenishing member action time stored to the replenishing member action time storing means 1030. COPYRIGHT: (C)2007,JPO&INPIT