| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reading device for stably obtaining high-quality images by preventing halation phenomenon and shortage in quantity of light. SOLUTION: The image reading device includes a light source formed by arranging a plurality of LEDs (light emitting devices) 53 in a line in the main scanning direction, and a light guiding plate 54 for guiding the light emitted from the light source to a document plane. In the image reading device, the light emitting planes 54A, 54B of the light guiding plate 54 are elliptic diffusing planes for diffusing the light in the main scanning direction without diffusing the light in the sub-scanning direction. Moreover, P is smaller than L×tanθ when the pitch between LEDs 53 is P, a half value angle of the LED 53, is θ, and distance between the light emitting plane (elliptic diffusing plane) 54A, 54B of the light guiding plate 54 and the LED 53 is L. COPYRIGHT: (C)2011,JPO&INPIT
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