| 摘要 |
PURPOSE: To control the concentration of toner in a developer at an electrophotographic printer. CONSTITUTION: A controller 100 receives the read of articulate area density SD from a densitometer 24 as its input and outputs an output to be used for controlling Vdev (by controlling Vbias and/PL) and controlling a toner supply part 19 to a developer unit 18. The Vdev is comparatively easily changed and can be controlled up or down by finding the optimum value of SD. With the exhaustion of supplied toner in the developer, the gradual decrease of articulate area density can be complemented to a certain degree rather than the increase of Vdev but the decrease of T/C is neutralized by directly adding the much more toner into the developer. The value of decrease of TC is logically estimated from the value of required Vdev, and the toner or the developer containing rich toner is put from a hopper 19 into the unit 18 so that the T/C can be increased. |
