Multi beam exposing device and exposing method using the same

An exposing device including modulating means which has a plurality of pixels and modulates, per pixel, an optical beam irradiated from a light source, for exposing a plotted image on an exposure surface by modulating, per pixel, the plurality of pixels of the modulating means based on image data, the multi beam exposing device comprising:

• beam position detecting means for detecting exposure point positional information pertaining to an optical beam irradiated on the exposure surface from predetermined pixels to be measured of the modulating means, which beam position detecting means measures an exposure point of the beam at two or more measurement points which are not aligned in the scanning direction with respect to the exposing head;
• and
• angle detecting means for detecting an angle, with respect to the scanning direction, of the beam position detecting means at each exposure point.

An exposing method for effecting exposure of a plotted image on an exposure surface by using means which has a plurality of pixels and modulates, per pixel, an optical beam irradiated from a light source, and modulating, per pixel, the plurality of pixels of the modulating means, based on image data, comprising the steps of:

• detecting exposure point positional information pertaining to an optical beam irradiated on the exposure surface from predetermined pixels to be measured of the modulating means;
• and
• calculating a relative positional deviation between positional information pertaining to the pixels to be measured of the modulating means and exposure point positional information pertaining to each of the optical beams projected at the exposure surface from each of the pixels to be measured, detected at the previous step, based on the two positional informations.