| 摘要 |
A printing apparatus has a sensor unit which optically detects, at a measurement position, a surface of a sheet, for measuring a moving state of the sheet. The sensor unit measures the moving state of the sheet when the sheet is located at the measurement position, and measures a moving state of a surface of the rotary member when the sheet is not located at the measurement position. The sensor unit has at least one of an image sensor arranged to perform imaging of one of the surface of the sheet and the surface of the rotary member so as to obtain image data, based on which the moving state is measured and a Doppler velocity sensor. |
