Patent ID: 7071963

Claim:
A method for inspecting an image forming apparatus, the image forming apparatus including an optical write-in head which applies light carrying image information to a photosensitive substance, the optical write-in head including an array light source having a plurality of dot light sources each selectively emitting the light corresponding to the image information and a lens array facing the array light source, wherein the lens array has a plurality of lens elements which corresponds to the plurality of dot light sources respectively, the method comprising the steps of: arranging the array light source and a light receiving element which receives the light from the plurality of dot light sources at a conjugate position with respect to the lens array; lighting up the array light source through a uniform light emitting pattern all over an effective width of the lens array; moving the array light source and the lens array toward the light receiving element in a direction in which lenses of the lens array are arranged to thereby cause the light receiving element to detect a light amount of each of the dot images interconnected by the lens array; obtaining the contrast of all the dot images in an image forming range in which lens array interconnects the dot images; dividing the image forming range at a predetermined width to form a plurality of image forming sections; calculating the average of the contrasts of the dot images in each of the sections in accordance with a detection result by the light receiving element; and deciding whether a difference between the average and the minimum of the contrasts of the dot images in each of the sections is not more than a predetermined value.