Patent ID: 7982924

Claim:
An image reading device comprising: conveying means for conveying in a conveying direction a target to be light-irradiated including a hologram region; a light guide extending in a main-scanning direction and a sub-scanning direction; a first light source, provided at an end portion of the light guide, in which light sources are arranged in an array along the main-scanning direction, for emitting light having a plurality of wave lengths in the sub-scanning direction into the light guide; a second light source, provided at an end portion of the light guide, in which light sources are arranged in an array in the main-scanning direction along the arrangement of the first light source, for emitting light having a plurality of wave lengths in the sub-scanning direction into the light guide; a first total reflection face, formed at a position where optical axes of the first light source intersect with the light guide, for totally reflecting light emitted from the first light source in the sub-scanning direction to a light irradiated portion where the hologram region is to be irradiated with light; a second total reflection face, having a slant angle different from that of the first total reflection face, formed at a position where optical axes of the second light source intersect with the light guide, for totally reflecting light emitted from the second light source in the sub-scanning direction to the portion to be irradiated with light; lighting control means for controlling in a time-division manner an exposure ratio between light quantities incident on the first total reflection face and the second total reflection face; a lens assembly for focusing reflection light reflected by a reflective portion of the target positioned at the light irradiated portion; and a sensor for receiving, for each divided time, light focused by the lens assembly, the light irradiated portion being irradiated with light from the first total reflection face and the second total reflection face by their irradiation angles being different from each other.