| 摘要 |
<P>PROBLEM TO BE SOLVED: To exactly grasp the absolute position of a transfer member by compensating an error by environmental change or secular change. <P>SOLUTION: The light receiving part 14a of a light receiving part unit 14 outputs a first detection signal yk(s) which is continuous quantity according to light OP1 for detection to be received via the gray scale part 41 of a shutter 40. The light receiving part 14b of the light receiving part unit 14 outputs a second detection signal yk(p) which is a binary signal according to light OP2 for detection to be received via the slit part 42 of the shutter part 40. A straight line LA is obtained from a value YR at a rest position RP and a value YE at an end position EP of the first detection signal yk(s), inclination of the straight line LA is grasped from values Y1, Y2 of the first detection signal yk(s) at the point of time of rise of the second detection signal yk(p) and distance D between positions X1 and X2, and an output characteristic straight line LB is uniquely specified from the straight line LA and the inclination of the straight line LA. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
