| 摘要 |
PROBLEM TO BE SOLVED: To provide an original front end detector which can surely detect the front end of an original in an original reader for continuously detecting both ends of the original within an effective reading range of the reader without erroneously detecting both ends of the original and to eliminate the actuators and photosensors used heretofore. SOLUTION: When there is a command for reading the original from a user, means 28 for conveying the original is driven to the prescribed extent and the change points of first to fourth image signals are detected by performing scanning respectively in the black segments and white segments of a black and white reference plate 1. Means 26 for judging the presence or absence of the original of the reader capable of continuously detecting both ends of the original in accordance with these change points makes judgment that the original is not set when the change points cannot be detected and the means makes judgment that the original is set when the change points can be detected. COPYRIGHT: (C)2004,JPO
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