| 摘要 |
PURPOSE:To enable execution of accurate measurement by a method wherein an optical image of an index for measurement is converted into an electric signal while it is scanned and exposed on a photoelectric conversion element by driving a scanning optical system actually, the electric signal is transferred to a transfer element and the optical image is detected therefrom sequentially. CONSTITUTION:An index 14 for measurement is set along a scanning direction A on platen glass 1 and an image of the index 14 is scanned and exposed on a line image sensor 17 by driving a scanning optical system 11. On the occasion, the linear image of the index 14 is illuminated by a light source 2, while a reflected light image thereof is scanned and exposed on the sensor 17 disposed at a position corresponding to the surface of a drum 10 of a light-sensitive body, through a full rate mirror 3, half rate mirrors 4 and 5, an imaging lens 6 and a fixed mirror 7. On the occasion, the light source 2 and the mirror 3 are driven at a speed V in the direction A, while the mirrors 4 and 5 are driven at a speed V/2 in the same direction. The speed of movement of a carriage moving the mirrors of the scanning optical system 11 is detected by a linear type transducer for speed detection and inputted to a driving circuit 30 of the sensor 17, and thereby the scanning optical image can be detected. |
