Patent ID: 7170660

Claim:
An optical scanner comprising: a plurality of unit modules arranged in a main scanning direction, each unit module having a light source that modulates according to image data and a deflection unit which deflects the light emitted from the light source to scan a surface to be scanned, wherein areas scanned with each unit module are joined together to record the image, wherein the image data includes fixed pixel areas in number equal to the number of the unit modules and which have one scanning line in common with the adjacent fixed pixel area, and variable pixel areas that link up the fixed pixel areas, wherein the image data is constructed by adding pixels of each unit module to the variable pixel areas at a record start side or a record stop side of the fixed pixel areas, and the variable pixel areas are commonly shared between two neighboring unit modules; and a mask signal generating unit that generates mask signals as soon as part of the pixels in the variable pixel area turn invalid with respect to one or the other of the unit modules adjacent to each other.