Patent ID: 6547355
Filing Date: 2003-04-15
Classification: B41J

Abstract:
A printing apparatus comprising:a head having a plurality of nozzles that eject ink; a main scanning unit that carries out main scanning by moving the head forward and backward in prescribed directions relative to a print medium; a head driving unit that drives the head in at least one of the forward and reverse passes in accordance with print data and forms dots on at least some of a plurality of pixels aligned in the main scanning direction; a sub-scanning unit that carries out sub-scanning by moving the print medium forward relative to the head in a sub-scanning direction that is perpendicular to the main scanning direction; and a control unit that controls printing, wherein the print data includes raster data having: image pixel value data indicating a dot formation status at image pixels that constitute images, and being two-dimensional image data indicating the pixels aligned in the two dimensions of the main scanning direction and the sub-scanning direction; adjustment pixel value data indicating existence of adjustment pixels in which dots are not formed and which are used to adjust positions of the image pixels in the main scanning direction and are located in at least one end of the image pixel value data, with regard to each nozzle for each main scanning session, wherein the control unit includes: an image pixel value data memory unit that stores the image pixel value data; a misalignment amount memory unit that stores an amount of the dot formation position misalignment; a determining unit that determines the relationship of correspondence between each nozzle mounted in the head and the two-dimensional image data in accordance with an amount of sub-scan feed; an allocation setting unit that allocates the adjustment pixels to one or both ends of the image pixel value data based on the determination so that the misalignment amount is corrected; a raster data generating unit that generates the raster data from the image pixel value data and the allocation of the adjustment pixels, and corrects, in dot formation in accordance with the print data, dot formation position misalignment in the main scanning direction for each nozzle, using the image pixel value data and the adjustment pixel value data.