Patent ID: 7589755
Filing Date: 2009-09-15
Classification: B41J,G03F

Abstract:
1. An apparatus for recording an image on a photosensitive material by irradiation with light, comprising: a light source emitting light; a spatial light modulator of diffraction grating type, having a plurality of grating elements each of which is one set of a strip-like fixed reflective surface and a strip-like moving reflective surface extending in a direction perpendicular to a predetermined arrangement direction, said plurality of grating elements being arranged in said arrangement direction; an optical system for directing either zeroth order light beams or (+/−) first order diffracted light beams from said spatial light modulator irradiated with light by said light source, onto a photosensitive material; a scanning mechanism for moving an irradiation position on said photosensitive material of light from said spatial light modulator in a scan direction perpendicular to a width direction corresponding to said arrangement direction; and a writing controller for switching each of said plurality of grating elements between a diffracting state and a reflecting state in synchronization with movement of said irradiation position, wherein a minimum line width to be written on said photosensitive material corresponds to a width of a predetermined number of grating elements where said predetermined number is three or more and less than the number of said plurality of grating elements, each group of grating elements which are spatially continuously in said diffracting state or spatially continuously in said reflecting state consists of said predetermined number of grating elements or more while writing is performed, a moving distance in said scan direction of said irradiation position on said photosensitive material between a switching of state in each grating element and a subsequent switching of state is equal to or larger than said minimum line width and said moving distance is variable and an integral multiple of a length obtained by dividing said minimum line width by said predetermined number, and information representing inexistence of switching or a time of switching between said diffracting state and said reflecting state of each grating element which is performed while said irradiation position is moved in said scan direction by a distance equal to said minimum line width is inputted from said writing controller to a driving circuit of said spatial light modulator every time when said irradiation position is moved in said scan direction by a distance of said minimum line width.