| 摘要 |
PROBLEM TO BE SOLVED: To measure displacement of a transfer belt with high accuracy.SOLUTION: A displacement detection device compensates, with a temperature change rate of a focal distance of an imaging optical system 12 (imaging lens 12), an error in a detection length due to an influence of a change in temperature of relative positions of a light source 11, the imaging lens 12, and a light sensor 13 (sensor body 13) caused by thermal expansion of a housing 14. The displacement detection device can thereby suppress fluctuation of the detection length relative to a change in temperature, and therefore can measure displacement of a transfer belt with high accuracy and use a result of the measurement to drive the transfer belt with high accuracy. |
