| 摘要 |
<p>PURPOSE:To miniaturize an LED print head by constituting it of a rod lens array for converging an emission of an LED array chip on a surface of a photosensitive drum, and of means for changing the direction of the light to the surface of the photosensitive drum. CONSTITUTION:An LED array chip 1, a driver IC 2, and a circuit pattern are provided on a ceramic substrate 4. A mirror 5 is arranged on an optical path of the LED array chip 1 in such a manner that a light from the LED array chip 1 as a light source reflects and the optical path changes to a right angle. The reflected light passes through a center of a converging rod lens array 6 and impinges on a surface of a photosensitive drum 7. At this time, a sum of lengths B+C1, where C1 represents a length between the LED array chip 1 as a light source and the mirror 5 and B represents a length between the mirror 5 and the converging rod lens array 6, is equal to a length from the converging rod lens array 6 to the photoconductor drum 7 (TC-L)/2. Also, the TC which represents a focal length between the LED array chip 1 as a light source and the photoconductor drum 7 can be expressed as TC=(TC-L)/2+L +(B+C1).</p> |
