| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of securing the optimum toner density in any condition to obtain a satisfactory image by preventing excessive supply of toner. <P>SOLUTION: Test supply of toner is performed before starting a printing operation. When an output voltage Vt does not settle at a prescribed value or lower within a prescribed time, the on/off of a toner supply mechanism is not determined by the difference between the output voltage Vt and a reference voltage Vref but an image density determination pattern is prepared. A time (hereinafter on-time) in which the toner supply mechanism is turned on is determined according to an image density corresponding voltage Vsp and an image area to be printed. In accordance with this embodiment, the timing at which the relation between the output voltages Vt and TC is unstable is detected by the test supply, and the toner calculated according to the image density and an image area ratio is supplied during that time period. Thus, the excessive supply is prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT |
