| 摘要 |
PROBLEM TO BE SOLVED: To realize to make an image carrier exert a high resolution and a high image quality by detecting a rotational speed of the image carrier highly accurately and inexpensively. SOLUTION: A surface velocity of the image carrier 1 is detected with the use of a detector provided with a transmitter S for transmitting ultrasonic waves fs to a surface of the image carrier 1, and a receiver O for receiving reflected waves fo reflected at the surface of the image carrier 1. Accordingly, to rotate the image carrier 1 highly accurately is realized, and the detection is enabled stably at all times without being affected by toner contamination, slide flaws or the like at an observation face of the image carrier 1. |
