SHEET SUPERPOSING FEEDING DETECTION METHOD, SHEET FEEDING DEVICE AND IMAGE READING DEVICE USING THIS

摘要

PROBLEM TO BE SOLVED: To provide an inexpensive sheet feeding device with a simple structure and a superposing feeding detection method, which always accurately detect superposing of sheets when the superposing of the sheets paid out from a stacker is detected even if the sheets having non-standard-size variant size are fed and the sheets are superposing-fed while they are largely deviated in the longitudinal direction.

SOLUTION: A sheet size recognition means 49 for determining conveying direction length of the sheet is provided on the stacker 1 placed with the sheets and a superposing feeding detection means 6 such as a supersonic sensor is arranged between two conveying means in a conveying guide 3 for guiding the sheets from the stacker 1 to a processing platen 2. Simultaneously, a conveying length detection means 20 for detecting length of the sheet from a distal end to a rear end of the sheet conveyed is provided in the above conveying guide 3. A determination means for determining abnormal conveying of the sheet based on a comparison result (long or short) from a comparison means for comparing conveying length of the sheet detected by the conveying length detection means with the conveying direction length of the sheet detected by a sheet size recognition means 49 and a detection result (one sheet or a plurality of sheets) from the superposing feeding detection means is provided.

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