| 摘要 |
<P>PROBLEM TO BE SOLVED: To determine a state of developer stored in a developing unit by means of rotation of developing means. <P>SOLUTION: A rotary developing part 21 includes developing units 210Y, 210M, 210C, 210K equipped with sensors 121Y, 121M, 121C, 121K, respectively, for measuring toner density. An image forming device with the rotary developing part 21 measures toner density for a certain developing unit, in a state (0°) where the developing unit faces a photoreceptor drum 111 and other states (90°, 180°, 270°), to determine the state of the developer on the basis of the difference between the measured toner densities. For example, the image forming device determines that the developer is solidified in the developing unit when the difference between the toner densities measured in four states is less than a predetermined threshold (or there is little difference). <P>COPYRIGHT: (C)2013,JPO&INPIT |
