| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an exposure device, an LED head, an image forming apparatus and a reading apparatus, where high resolution and good image quality can be obtained even if the shape accuracy of a lens and mounting-position accuracy are alleviated. <P>SOLUTION: In the exposure device including a light emitting portion array comprising a plurality of light emitting portions and a lens array disposed in nearly parallel to the light emitting portion array, the respective light emitting portions are nearly linearly arranged with a specific interval PD, the respective lens assembly members are arrayed in a direction nearly perpendicular to respective optical axes. The optical axes of the plurality of lenses respectively align with the optical axis of the lens that is included in the adjacent lens assembly member and also disposed facing each other. Provided that the focal length of each of the plurality of lenses is expressed by FO, and a distance between the lens and the light emitting part array is expressed by LO, and when light beams parallel to the optical axes of the lenses are made incident on the plurality of lenses from the direction of a light shielding member, a spot having a radius RS satisfying a conditional expression (1) is formed on a plane away at FO from the lens assembly member toward the light emitting portion. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
