| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain adverse influence on a photoreceptor or the life of developer by facilitating judgement about switching from a color mode to a monochrome mode in a tandem type color image forming apparatus. <P>SOLUTION: The number of pixels of printed original images Y, M and C is acquired to decide whether or not it is a monochrome image based on the acquired number of pixels and the predetermined threshold of the number of pixels. When obtaining the result of decision showing that it is the monochrome image, the driving time of a replenishing motor is measured, and the measured driving time is recorded, while the recorded driving time is cleared when obtaining the result of decision showing that it is not the monochrome image. When measuring the driving time, whether or not a printing mode is switched is decided based on the driving time and the predetermined threshold of the driving time. When obtaining the result of decision showing that the printing mode is switched, the printing mode is switched from the color mode to the monochrome mode. <P>COPYRIGHT: (C)2008,JPO&INPIT |
