| 摘要 |
PROBLEM TO BE SOLVED: To predict toner clogging in a toner recovering mechanism using a stepping motor as a drive source.SOLUTION: A drive control unit 3 changes a rotational speed of a stepping motor 57 to a first rotational speed that is faster by two levels than a reference rotational speed; and a step-out detecting unit 7 refers to a drive condition data from a drive detecting unit 2 and checks the presence or absence of step-out in the first rotational speed. When step-out is detected in the first rotational speed, the drive control unit 3 changes the rotational speed of the stepping motor 57 to a second rotational speed that is faster by one level than the reference rotational speed; and the step-out detecting unit 7 refers to a drive condition data outputted from the drive detecting unit 2 and determines the presence or absence of step-out in the second rotational speed. When the presence of step-out in the second rotational speed is determined, a window time predicting unit 8 calculates a window time reaching to a toner clogging state based on the relation between a time point when the step-out occurs in the first rotational speed and a time point when the step-out occurs in the second rotational speed. |
