Document conveying device and image forming device

Abstract

A document conveying device (6) includes a document conveying unit (63), a controller (100), first and second document detectors (661,662), a pulse count detector (101), and a determining unit (102). The first document detector (661) is disposed on a conveying path along which a document is conveyed by the document conveying unit (63), and detects a document leading edge. The second document detector (662) is disposed at a position different from that of the first document detector (661) in both a document conveying direction and a direction orthogonal thereto, and detects the document leading edge. The determining unit (102) determines whether the number of pulses detected by the pulse count detector (101) during the period from detection of the document leading edge by one of the first and second document detectors (661,662) to detection of the document leading edge by the other exceeds a predetermined value (Pa,Pb). If the number of pulses exceeds the predetermined value (Pa,Pb), the controller (100) stops the document conveying operation.

Description

technical field [0001] The present invention relates to a document conveyance device and an image forming apparatus, and particularly relates to document conveyance control when the document is skewed during conveyance. Background technique [0002] In a document transport device that transports a document to a document reading unit such as a scanner, the document may be damaged when the document is transported in a state inclined relative to the document transport direction. A document conveying device that detects the inclination of the document. For example, there is known a document conveying device in which two sensors for detecting the front end of a conveyed document are arranged in parallel on a line perpendicular to the conveying direction of the document, and the document is driven by a pulse signal. The difference in the number of pulses between the time when the conveyance drive motor starts driving and the time when each sensor detects the leading edge of the d...

AI Technical Summary

Problems solved by technology

[0003] However, since the above-mentioned original conveying device needs to arrange both sensors on a line perpendicular to the above-mentioned original conveying direction without any deviation from each other, accuracy is required for the arrangement position of each sensor.

Moreover, since the above-mentioned original conveying device assumes that there is no positional deviation in the arrangement position of each sensor, and judges the amount of inclination of the original based on the difference in the number of pulses until the time when each of the sensors detects the front end of the original, the amount of inclination of the original is determined. When the position of the arrangement deviates from the above position, the number of pulses mentioned above cannot be accurately calculated, and errors may occur in the detected tilt of the original.

Therefore, there is a possibility that document conveyance control, which switches between continuation and suspension of document conveyance according to the amount of document inclination, cannot be accurately performed.

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