| 摘要 |
PROBLEM TO BE SOLVED: To appropriately adjust and maintain the stretched state of an endless belt-like photoreceptor by moving at least either a driving roller or a driven roller based on a belt tension detection signal. SOLUTION: The deformation under pressure of a rod 34 by the tension of the endless belt-like photoreceptor 21 is detected by a sensor 26. Based on the detection signal, a control part 27 outputs a control signal to a moving mechanism 25 in the case of deciding that the tension of the belt does not show an appropriate value, and rotates a driving motor in a normal direction or a reverse direction until the tension of the photoreceptor 21 shows a value equal to a reference value. When the driving motor is rotated, an eccentric cam changes a pressing amount to the part to be pressed of the rod 34 corresponding to the rotational angle thereof. Therefore, the driven roller 24 is moved in a direction where it resists to the tension of the photoreceptor 21 or a direction where it follows the tension thereof, and the mutual positions of the driven roller 24 and the driving roller 22 are changed, then the tension of the photoreceptor 21 is set to the appropriate value. |
