Image reading apparatus and image scanning apparatus

Abstract

The invention provides an image reading apparatus and an image scanning apparatus. In the image scanning apparatus, when documents on a document tray are sequentially transferred, different control steps are performed according to a scanning speed when an upper surface height of the documents is lowered thereby turning off a height detection sensor. In a low scanning speed, the document tray is elevated one time until the upper surface height becomes a target height which is higher by a predetermined distance since a height detection sensor is turned on at an inter-transfer time between completion of document transfer and start of a subsequent document transfer. In an intermediate scanning speed, the document tray is elevated little by little in each transfer of one document at the inter-transfer time until the upper surface height reaches the target height. In a fast scanning speed, the transfer of the document is tentatively interrupted, the document tray is elevated one time until the upper surface height reaches the target height, and the transfer of the document is resumed.

Description

technical field [0001] The present invention relates to a structure of an image reading device suitable for reading a large number of documents at a time. [0002] This application claims the priority of Japanese Patent Application No. 2007-067329 filed on March 15, 2007, the entire contents of which are incorporated herein. Background technique [0003] Japanese Unexamined Patent Application Publication No. 2006-16093 discloses a copying machine capable of stacking multiple pages of originals on an original tray (original feeding tray) and having an upper limit position detection sensor for detecting the uppermost original. In the copying machine described in Japanese Patent Application Laid-Open No. 2006-16093, the number of original pages decreases as the originals on the original tray are supplied, and the control device controls the disk drive mechanism based on the detection result of the upper limit position detection sensor to Always position the top original at the...

AI Technical Summary

Problems solved by technology

Therefore, in Patent Document 1, when the document tray is raised during document reading, the document being conveyed may fluctuate due to the raising of the document tray, resulting in deterioration of the read image quality.

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