Patent ID: 7161611

Claim:
An exposure system for exposing a color photosensitive body including therein first, second and third photosensitive materials which respectively develop into cyan, magenta and yellow comprising an exposure head formed by a surface emitting element array formed by a plurality of first to third linear emitting element arrays arranged in a sub-scanning direction substantially perpendicular to a main scanning direction, each of the first linear emitting element arrays comprising a plurality of first light emitting elements which are arranged in the main scanning direction at predetermined pitches and each of which sensitizes the first photosensitive material, each of the second linear emitting element arrays comprising a plurality of second light emitting elements which are arranged in the main scanning direction at predetermined pitches and each of which sensitizes the second photosensitive material, and each of the third linear emitting element arrays comprising a plurality of third light emitting elements which are arranged in the main scanning direction at predetermined pitches and each of which sensitizes the third photosensitive material, and a sub-scanning means which moves the color photosensitive body and the exposure head in the sub-scanning direction relatively to each other, so that the same parts of the photosensitive body are exposed a plurality of times respectively by the first to third linear emitting element arrays with progression of the sub-scanning, thereby exposing the color photosensitive body to two-dimensional imagewise light, wherein the improvement comprises that the first to third linear emitting element arrays satisfy conditions Ny<Nm and Nc≦Nm, wherein Nc, Nm and Ny respectively represent the numbers of the first to third linear emitting element arrays.