Patent ID: 8259364
Filing Date: 2012-09-04
Classification: H04N

Abstract:
1. An image sensor comprising: a light transmissive member, which includes a conveying region where a document is conveyed, the light transmissive member extending in a first direction which is (1) orthogonal to a direction of conveying the document and (2) parallel to a face of the conveyed document; a reference portion provided on the light transmissive member outside the conveying region of the light transmissive member with respect to the first direction, the reference portion having a transmittance lower than a transmittance of the conveying region; a light source unit that irradiates light to the conveying region and the reference portion such that the irradiated light is transmitted through the conveying region and the reference portion; a rod lens array, which is arranged to be opposed to the light source unit, the rod lens array extending in a second direction which is orthogonal to the face of the conveyed document, and which contemporaneously converges a first light irradiated from the light source unit which is transmitted through the document conveyed in the conveying region and a second light irradiated from the light source unit which is transmitted through the reference portion outside the conveying region; a light receiving unit that contemporaneously receives the first light corresponding to the conveying region and the second light corresponding to the reference portion, through the rod lens array, and outputs a first electric signal corresponding to the conveying region and a second electrical signal corresponding to the reference portion; an amplifying unit that amplifies the first electric signal for the document corresponding to the conveying region of the light receiving unit and outputs an image signal of the document; and a controlling unit that controls an amplification factor of the amplifying unit based on the second electric signal corresponding to the reference portion of the light receiving unit to increase or reduce the outputted image signal of the document in the amplifying unit.