Patent ID: 6124876
Filing Date: 2000-09-26
Classification: B41J,G02B,G02F

Abstract:
An image-wise exposure apparatus comprising:a light source for emitting recording light to which a photosensitive material is exposed,a mirror array device comprising a plurality of small mirrors which are two-dimensionally arrayed in two directions normal to each other in positions where the small mirrors receive the recording light and a drive mechanism for changing orientations of the respective small mirrors independently from each other so that light impinging upon each of the small mirrors is reflected selectively in one of a first direction in which the reflected light impinges upon the photosensitive material and a second direction in which the reflected light does not impinge upon the photosensitive material,a control circuit which controls the drive mechanism according to an image signal, anda picture element shifting means which changes an optical relationship between the mirror array device and the photosensitive material to a second relationship after exposure of the photosensitive material to the recording light from the small mirrors with the mirror array device and the photosensitive material in a first relationship so that exposure dots are formed by exposure of the photosensitive material to the recording light from the small mirrors with the mirror array device and the photosensitive material in the second relationship between adjacent exposure dots formed by exposure of the photosensitive material to the recording light from the small mirrors with the mirror array device and the photosensitive material in the first relationship,wherein a size of each of the small mirrors is sufficiently close to mirror pitches in both the directions in which the small mirrors are arrayed, anda distribution of a reflectance of each small mirror is such that the reflectance of the small mirror is not smaller than a predetermined value only in a continuous region not longer than 1.5 a/m as measured in a direction in which the picture element shifting operation is carried out, wherein a represents the mirror pitches in a direction of the picture element shifting and m represents times by which a number of exposure dots are multiplied by the picture element shifting in the direction in which the picture element shifting operation is carried out.