| 摘要 |
PROBLEM TO BE SOLVED: To restrict an unneccessary residual-developer recovery operation and to suppress deterioration of image carriers and to hold electrification performances of electrifiers and to from a high quality image. SOLUTION: The densities of images formed on photoreceptor drums 342-345 are detected by video-signal count parts 220-223 in an image processing part 312. According to the number of sheets subjected to image formation in which the detected image densities exceed a specific image-density, a CPU in the image processing part 312 interrupts a print job, and controls residual-toner recovery operations by electrifiers 321, 324, 327, and 330 and developing units 322, 325, 328, and 331. |
