Apparatus and method that reduces streaking by using a deformed data portion to not array dots continuously in the main scan direction of the print head in the end portions of the sub-scan direction

Abstract

The present invention is intended to prevent appearance of streaks in head scanning direction at the joint of print data of the image to be printed. Print data composed of a multiplicity of dot information is supplied to a printing head having a plurality of dot forming elements arrayed along a sub-scanning direction. The printing head and the printing medium relatively move in main scanning direction and sub-scanning direction each other, and an image is printed on the surface of the printing medium. In the print data supplied by every main scanning action of the printing head, a deformed data portion of concave and convex shapes of waveform are formed, for example, so that dots may not be arrayed in parallel continuously in the main scanning direction of the printing head, at the joint of the ends of the sub-scanning direction. The undulation profile of this waveform is set in an ambiguous state, and the ambiguous state of the profile is not a state of a continuous profile line when the printed profile is observed visually.