Patent ID: 6033137
Filing Date: 2000-03-07
Classification: G06K,H04N

Abstract:
An ink jet printing apparatus using a printing head having a plurality of ink ejection elements arranged in a predetermined direction and performing printing on a printing medium on a basis of image data corresponding to said plurality of ink ejection elements, said apparatus comprising:test pattern printing means for printing a test pattern, based on the image data corresponding to the test pattern, on the printing medium to be used for printing by using the ink ejection elements of the printing head;reading means for reading density of the test pattern printed by said test pattern printing means so as to obtain density corresponding to each of said plurality of ink ejection elements used for printing said test pattern;setting means for setting correction data for correcting the image data corresponding to the ink ejection elements used for printing portions including at least both end portions of a printing region to be printed, on a basis of differences between the density corresponding to a first group of ink ejection elements including ink ejection elements at both end portions of the printing region and an average density value corresponding to a second group of ink ejection elements that excludes the first group of ink ejection elements;correction means for correcting the image data corresponding to said ink ejection elements at both end portions on a basis of the correction data set by said setting means; andcontrolling means for controlling correction of the image data performed by said correction means, the image data corresponding to the test pattern, when said setting means sets the correction data corresponding to the ink ejection elements, wherein said controlling means controls said correction means based on the correction data respectively corresponding to the first group of ink ejection elements and the second group of ink ejection elements.