摘要 |
A closed circuit control device for controlling carrier speed of a scanner. An optical meter is attached to the transparent glass panel of a scanner such that an image of the optical meter is formed on an optical sensor such as a charge couple device or a contact image sensor. Image of the optical meter is converted into sense signals by the optical sensor so that speed of the carrier can be accurately computed. Through the acquisition of an accurate carrier speed, scanning speed and direction can be precisely controlled.
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