Ink jet printing apparatus performing printing with correction of image data at boundary portion of image

摘要

When degree of a streak of density fluctuation is varied mainly due to variation of a printing medium to be used and/or variation of use environment of an apparatus to be impossible to correct the density fluctuation, at first, a test pattern is output (S72) with maintaining a second image correcting portion for correction inoperative (S71), and a correction coefficient of an image signal (S74 to S78) corresponding to ink ejection openings at end portions is set depending upon density fluctuation DELTA CSUM on the ink ejection openings at the end portions obtained from the result of reading (S73). By this, in an ink jet printing apparatus, the streak in a printed image can be constantly restricted irrespective of variation of the printing medium to be used and/or use environment of the apparatus. <IMAGE>