| 摘要 |
PROBLEM TO BE SOLVED: To realize a document size detecting method which detects document size with various kinds of size with high resolution and high precision, is at low cost and low power consumption. SOLUTION: In an original document reading apparatus including an LED array 2b arranged beneath an original document table 2a and having an alignment of point light source elements in a line direction, a means for supporting the LED array by a traveling object and relatively moving with an original document on the original document table and a photo acceptance unit that accepts reflected light of the illuminated original document, it is an original document detecting method that determines a size of the original document based upon a reaction of a pixel in the photo acceptance unit to the light reflected from the original document, the elements of the LED array 2b are divided into a plurality of blocks (a) to g, in an original document size detection mode, a traveling object is arranged at a position where the original document can be read, the light is turned on and off in turn per block from a block (d) corresponding to an original document minimum size on the original document reference side in the longitudinal direction of the LED array to a block (g) at the original document maximum size side, an end part of the original document is detected and original document width is detected. COPYRIGHT: (C)2005,JPO&NCIPI
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