| 摘要 |
PURPOSE:To always keep image density in a proper state by constituting a device in such a way that the signal of a toner state detection means is compared with a previously set control reference value so as to drive a toner supply means. CONSTITUTION:A photosensor 14 provided on a position where the image- formation area of a reference pattern plate 13 on the bottom surface of an original platen 12 passes detects the reflected light of the developed image on the pattern plate 13 and outputs a detection signal Vsp. Control reference values K1 and K2 which are the reference of the toner state are previously stored in control part 16 and while the signal Vsp does not fulfill the reference value K1, the supply of the toner by a supplying roller 7 is not needed because sufficient toner adheres to a detection pattern. When the signal Vsp exceeds the reference value K2, the toner is supplied with the driving of a driving device 15. Then, the image density can be always kept in the proper state. |
