| 摘要 |
PURPOSE:To prevent the occurrence of uneven printing on printing paper by an electrophotographic printer. CONSTITUTION:Three slits 29 are provided at a partition separating a part where a stirring part 6 and a screw 5 in a developing device 2 other than a slit. A shutter 8 closing the respective slits 29, at ordinary times and opening them according to an opening signal and an opening/closing mechanism 28 having an arm moving the shutter 8 in parallel with the rotary shaft of a photosensitive drum 12 are fixed. A pattern sensor 9 detecting the density of toner transferred on the printing paper 11 in a transfer part 15 and outputting an electrical signal at a level in proportion to the density is provided corresponding to the shutter 29 by the same number. A developing control part 10 which detects the level of the signal outputted from the sensor 9 and outputs the opening signal when the detected level becomes equal to or under a previously set one is provided, and the toner supplied to the stirring part 6 through the slit 29 is partially supplied so as to average the density of the toner supplied to the photosensitive drum 12. |
