Patent ID: 8891141
Filing Date: 2014-11-18
Classification: H04N

Abstract:
1. An image reading apparatus comprising: a document sheet table having a top surface on which a document sheet is placed; a first carriage that has a lighting portion which applies light from a light source so as to diffuse the light toward the document sheet table in a primary scanning direction, that has a first mirror which reflects, in a horizontal direction, light applied by the lighting portion and reflected by an image surface of the document sheet, and that can reciprocate in a secondary scanning direction orthogonal to the primary scanning direction; a second carriage that has a second mirror which reflects, downward, the light reflected by the first mirror, and that has a third mirror which, disposed below the second mirror, reflects, in the horizontal direction, the light reflected by the second mirror, and that can reciprocate in the secondary scanning direction in conjunction with the first carriage; a photoelectric converting portion that receives, as image light, light obtained by the light applied by the lighting portion being reflected by the image surface of the document sheet, further reflected by the first mirror, the second mirror, and the third mirror, and travelling in the horizontal direction, and that converts the received image light to an electrical signal; and a position detecting portion that detects an initial position in reciprocating of the first carriage, wherein the light source is disposed at an end portion, in the primary scanning direction, of the lighting portion, the lighting portion includes: a light guide member on which the light from the light source is incident, and which guides the incident light in the primary scanning direction and applies the light to the document sheet table; and a heat dissipating member that dissipates heat generated in the light source, the position detecting portion includes: a light emitter that emits light; a light receiver that receives the light emitted from the light emitter; and a detection member that moves in the secondary scanning direction along with the reciprocating of the first carriage, in order to detect the initial position of the first carriage, and the detection member is formed as a flat plate that is integrated with the heat dissipating member and extends in the secondary scanning direction.