| 摘要 |
PURPOSE:To exactly position a frame image in the center part of a screen easily and in a short time, by providing two sensor elements for detecting simultaneously the end part of the frame image in the width direction orthogonal to the flow direction of the frame image projected on the screen. CONSTITUTION:In order to detect exactly a prescribed one end part of a frame image 20 of a microfilm which is carried in both forward and backward directions, two pairs of sensors of consisting of two pieces of sensor elements 70, 71 are provided on the upstream side and the downstream side of a target stop position along the carrying direction by separating them in the width direction orthogonal to the carrying direction of the microfilm 1. Also, a rotating speed of a motor for carrying the microfilm 1 has three stages in both the forward and backward directions, and at the time of a retrieval, it is rotated at a high speed so that the retrieval can be executed at a high speed, and at the time of damping, it is rotated at a low speed and damped at a low speed, and also, by executing a super-low speed rotation of a lower speed than the low speed rotation, the frame image 20 is position exactly.
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