| 摘要 |
An exposure head is provided in which light beams from light emitting parts 63 pass through a transparent substrate 62 and are projected on an image carrier. The transparent substrate 62 has plain faces substantially parallel to each other, one of the faces being a face on which the light emitting parts 63 are formed and the other being a face from which light beams are projected. The transparent substrate 62 is provided, at position(s) other than the face on which the light emitting parts 63 are formed and than the face from which light beams are projected, with light quantity detecting means 100 for detecting the quantity of light emitted from said light emitting parts 63. In the exposure head in which the light emitting parts of organic EL light emitting elements are aligned into array configuration on the transparent substrate, the light quantity detecting means is disposed on an end face of the transparent substrate and light beams totally reflected at the projection-side face of the transparent substrate are introduced to the light quantity detecting means, thereby effectively detecting the quantity of light of the light emitting elements and thus providing improved accuracy of detecting the quantity of light. <IMAGE> |
