| 摘要 |
PROBLEM TO BE SOLVED: To prevent toner replenishment from being uselessly performed by detecting defect of separating operation for a transfer belt of a transfer-transporting device from an image carrier. SOLUTION: This image forming device is constituted so as to detect the toner density of an inspection pattern formed by the toner image on a photoreceptor drum 2 by an optical reflection system photosensor 11. When assuming the relation between the value Vsp2 of this sensor output at this time and the value Vsp1 at the previous time as the next inequality, 'Vsp2/Vsp1>2', the new detection value Vsp3 of the optical reflection system photosnesor 11 is obtained by imaging the inspection pattern while holding the transfer belt 15 of the transfer-transporting device 10 in contact with the photoreceptor drum 2 by the drive of a solenoid 16. Then, if the next equation is satisfied, 'Vsp3/Vsp2=1.0±0.1', it is considered that the state at the time of detecting the Vsp2 is reproduced, and why the next inequality is satisfied, 'Vsp2/Vsp1>2', is judged as an attribute of the defect of attach/detaching operation of the transfer belt 15. In such a case, the device performs the toner replenishment control by applying the value at the previous time as the control reference value Vref of the toner replenishment to the developing device 8, and gives warning to that effect to the user by means of the lighting of a LED or the like. |
