Patent ID: 6042213
Filing Date: 2000-03-28
Classification: B41J

Abstract:
An apparatus for correcting a printing characteristic of a printhead having a plurality of printing elements and memory means for storing data, comprising:printhead drive means for driving the printhead to perform experimental printing on a recording medium;detecting means for detecting a variation in density per a predetermined area of an image that has been printed on the recording medium, wherein the predetermined area is defined by N pixels in a first direction in which the plurality of printing elements are arrayed and M pixels in a second direction different from the first direction;correction-data generating means for generating, per the plurality of printing elements, correction data for correcting the variation in density detected by said detecting means; andwriting means for writing the correction data in said memory means of the printhead,wherein N is a positive integer greater than 1 and less than 9,M is a positive integer greater than 15 and less than 1025,dots are formed in the predetermined area by sampling pixels, anda resolution per N pixels is less than 300 dpi.