Patent ID: 9699340
Date: 2017-07-04
CPC Classifications: H04N

Claim:
1. An image reading device comprising: contact glass on which an original document is placed; a frame surrounding a periphery of the contact glass; a light emitting section configured to emit light toward the contact glass and the frame; a mirror; a sensor configured to receive first reflected light that has passed through the contact glass and then reflected off the mirror, and second reflected light that has been reflected off the frame and then reflected off the mirror, and detect a first received light amount resulting from the first reflected light and a second received light amount resulting from the second reflected light; a control section configured to compare temporal variation of the first received light amount with temporal variation of the second received light amount; a document cover mounted so as to be openable and closable relative to the contact glass; a first switch configured to detect whether or not the document cover is being closed relative to the contact glass; and a second switch configured to detect whether or not the document cover is closed relative to the contact glass, wherein the control section determines whether or not the temporal variation of the first received light amount indicates presence of the original document on the contact glass using the temporal variation of the second received light amount as a reference, and the control section compares the temporal variation of the first received light amount with the temporal variation of the second received light amount after the first switch has detected that the document cover is being closed and before the second switch detects that the document cover is closed.