Patent ID: 8056896

Claim:
An image scanning apparatus comprising: a document tray arranged to receive a plurality of documents; an image scanning unit arranged to scan the documents; a transfer unit arranged to transfer the documents on the document tray one by one toward the image scanning unit; a lifting and lowering device arranged to lift and lower the document tray; a height detection sensor arranged to detect an upper surface height of the documents stacked on the document tray; and a control unit arranged to control the lifting and lowering device; wherein the control unit controls the lifting and lowering device while switching between a first control mode and a second control mode; and the height detection sensor detects that the transfer unit has transferred the documents so as to lower the upper surface height of the documents to below a predetermined height such that: in the first control mode, the control unit suspends the transfer of the document by the transfer unit, the control unit elevates the document tray until the upper surface height reaches a target height that is higher by a predetermined distance than when the height detection sensor detects that the upper surface height becomes higher than the predetermined height, and the control unit resumes the transfer of the document by the transfer unit; and in the second control mode, the control unit elevates the document tray until the document tray reaches the target height, while the transfer unit continues the transfer of the document.