| 摘要 |
PURPOSE:To excellently control image quality by controlling a sleeve so that it may rotate at a low speed in the case of the printout of a document for which comparatively low image quality is enough and it may rotate at a high speed in the case of the printout of a document for which comparatively high quality image is required. CONSTITUTION:First, an image quality mode, that means, whether the image which should be printed out is of high image quality or normal image quality, and a variable density mode, that means, whether image density is dense, normal, or sparse are inputted by an operation key 10. Next, whether the mode is the high image quality mode or not is judged, and in the case of the high quality image mode, the frequency of a clock pulse from a driving device 13 is made high and a speed variable control motor 4 is rotated at a high speed. Meanwhile, in the case of the normal image quality, the frequency of the clock pulse from the device 13 is made low and the motor 4 is rotated at a low speed. Then, whether the variable density mode shows dense, normal or sparse is judged, and developing bias impressed on the sleeve 2 is controlled in a high voltage power source 14 corresponding to the mode. |
