Image processing apparatus and image processing method

Abstract

Replacement processing is executed when the number of times of permission for a pixel corresponding to an ejection defective nozzle in a mask pattern is larger than a smallest number of times of permission, of the numbers of times of permission for pixels corresponding to ejection normal nozzles.

What is claimed is: 
     
         1 . An image processing apparatus that generates print data used for K (K≧3) times of relative scanning to a unit area on a printing medium, the relative scanning being performed by a printing head that ejects ink, the image processing apparatus comprising:
 an acquiring unit configured to acquire image data, information indicating a number of times of ejection of ink from zero to N (2≦N≦K) times for each of a plurality of pixel regions in the printing medium being determined for each of a plurality of pixels in the image data; and 
 a generation unit configured to generate the print data corresponding to the K times of scanning based on the image data and K mask patterns, information indicating a number of times of permission for ejection of ink from zero to N times for each of the plurality of pixel regions being determined for each of the plurality of pixels in the K mask patterns, 
 wherein, among K pixels in the K mask patterns each corresponding to a same pixel region, (i) for N pixels, information indicating different numbers of times of permission is determined, the different numbers being varied from one to N, and (ii) for K−N pixels, information indicating that the number of times of permission is zero is determined. 
 
     
     
         2 . The image processing apparatus according to  claim 1 , wherein the generation unit generates the printing data by using a table in which ejection or non-ejection of ink for each of the plurality of pixel regions is defined in accordance with the information determined in the image data and the information determined in the mask pattern. 
     
     
         3 . The image processing apparatus according to  claim 2 , wherein the table defines (i) ejection of ink in a case where the number of times of permission indicated by information determined in the image data is M (1≦M≦N) times and the number of time of permission indicated by the information determined in the mask pattern is L (1≦L≦N) times, and (ii) non-ejection of ink in a case where the number of times of permission indicated by information determined in the image data is M times and the number of time of permission indicated by the information determined in the mask pattern is L−1 times. 
     
     
         4 . The image processing apparatus according to  claim 3 , wherein the table defines non-ejection of ink in a case where the number of time of ejection indicated by the information determined in the image data is M−1 times and the number of times of permission indicated by the information determined in the mask pattern is L times. 
     
     
         5 . The image processing apparatus according to  claim 4 , wherein M+L=N+1. 
     
     
         6 . The image processing apparatus according to  claim 1 , wherein numbers of pixels in which information indicating a same number of times of permission is determined are substantially same among the K mask patterns. 
     
     
         7 . The image processing apparatus according to  claim 1 , wherein the information determined in the image data and the information determined in the mask pattern are each a (a≧2)-bit information. 
     
     
         8 . The image processing apparatus according to  claim 7 , wherein N=(2̂a)−1. 
     
     
         9 . The image processing apparatus according to  claim 1 , wherein N<K. 
     
     
         10 . The image processing apparatus according to  claim 1 , wherein K=4 and N=3. 
     
     
         11 . The image processing apparatus according to  claim 1 , further comprising the printing head. 
     
     
         12 . The image processing apparatus according to  claim 1 , further comprising a storing unit configured to store the K mask patterns. 
     
     
         13 . An image processing apparatus that generates printing data used for K (K≧3) times of relative scanning to an unit area on a printing medium, the relative scanning being performed by a printing head that ejects ink, the image processing apparatus comprising:
 an acquiring unit configured to acquire image data, information indicating a number of times of ejection of ink from zero to K times for each of a plurality of pixel regions in the printing medium being determined for each of a plurality of pixels in the image data; and 
 a generation unit configured to generate the print data corresponding to the K times of scanning based on the image data and K mask patterns, information indicating a number of times of permission for ejection of ink from once to K times for each of the plurality of pixel regions being determined for each of the plurality of pixels in the K mask patterns, 
 wherein, in K pixels in the K mask patterns each corresponding to a same pixel region, information indicating different numbers of times of permission is determined, the different numbers being varied from one to N. 
 
     
     
         14 . The image processing apparatus according to  claim 13 , wherein the generation unit generates the printing data by using a table in which ejection or non-ejection of ink for each of the plurality of pixel regions is defined in accordance with the information determined in the image data and the information determined in the mask pattern. 
     
     
         15 . The image processing apparatus according to  claim 14 , wherein the table defines (i) ejection of ink in a case where the number of times of permission indicated by information determined in the image data is M (1≦M≦K) times and the number of time of permission indicated by the information determined in the mask pattern is L (1≦L≦K) times, and (ii) non-ejection of ink in a case where the number of times of permission indicated by information determined in the image data is M times and the number of time of permission indicated by the information determined in the mask pattern is L−1 times. 
     
     
         16 . The image processing apparatus according to  claim 15 , wherein the table defines non-ejection of ink in a case where the number of time of ejection indicated by the information determined in the image data is M−1 times and the number of times of permission indicated by the information determined in the mask pattern is L times. 
     
     
         17 . The image processing apparatus according to  claim 13 , wherein numbers of pixels in which information indicating a same number of times of permission is determined are substantially same among the K mask patterns. 
     
     
         18 . The image processing apparatus according to  claim 13 , wherein the information determined in the image data and the information determined in the mask pattern are each a (a≧2)-bit information. 
     
     
         19 . A method for generating print data used for K (K≧3) times of relative scanning to a unit area on a printing medium, the relative scanning being performed by a printing head that ejects ink, the method comprising:
 acquiring image data, information indicating a number of times of ejection of ink from zero to N (2≦N≦K) times for each of a plurality of pixel regions in the printing medium being determined for each of a plurality of pixels in the image data; and 
 generating the print data corresponding to the K times of scanning, based on the image data and K mask patterns, information indicating a number of times of permission for ejection of ink from zero to N times for each of the plurality of pixel regions being determined for each of the plurality of pixels in the K mask patterns, 
 wherein, among K pixels in the K mask patterns each corresponding to a same pixel region, (i) for N pixels, information indicating different numbers of times of permission is determined, the different numbers being varied from one to N, and (ii) for K−N pixels, information indicating that the number of times of permission is zero is determined. 
 
     
     
         20 . A method for generating printing data used for K (K≧3) times of relative scanning to an unit area on a printing medium, the relative scanning being performed by a printing head that ejects ink, the method comprising:
 acquiring image data, information indicating a number of times of ejection of ink from zero to K times for each of a plurality of pixel regions in the printing medium being determined for each of a plurality of pixels in the image data; and 
 generating the print data corresponding to the K times of scanning based on the image data and K mask patterns, information indicating a number of times of permission for ejection of ink from once to K times for each of the plurality of pixel regions is determined for each of the plurality of pixels in the K mask patterns, 
 wherein, in K pixels in the K mask pattern each corresponding to a same pixel region, information indicating different numbers of times of permission is determined, the different numbers of times being varied from one to N.