Image processing apparatus and image processing method

An image processing apparatus for generating print data used in each of K relative scans performed on a unit area on a print medium by a print head for discharging ink, the print data determining discharge or non-discharge of ink to each pixel area corresponding to a plurality of pixels in the unit area, the image processing apparatus comprising:

• a first acquisition unit configured to acquire image data that corresponds to an image to be printed in the unit area and that determines an attribute of each of the plurality of pixels in the image and a number of discharges of ink from zero to N (N≧2) to each of the plurality of pixels;
• and
• a generation unit configured to generate the print data based on the image data acquired by the first acquisition unit, and K mask patterns that correspond to the K scans of the unit area and that determine the attribute of each of the plurality of pixels in the image and an allowable number of discharges of ink from zero to N to each of the plurality of pixels, wherein
• first print permitting pixels whose attribute is a first attribute and allowable number of discharges is M (1≦M≦N), and second print permitting pixels whose attribute is a second attribute different from the first attribute and allowable number of discharges is M are placed in the K mask patterns such that (i) a difference between the number of the first print permitting pixels placed in J (1<J<K) mask patterns corresponding to J scans from the first scan to the J-th scan among the K scans and the number of the first print permitting pixels placed in K−J mask patterns corresponding to K−J scans from the J+1-th scan to the K-th scan among the K scans is a first value, and (ii) a difference between a number of the second print permitting pixels placed in the J mask patterns corresponding to the J scans and the number of the second print permitting pixels placed in the K−J mask patterns corresponding to the K−J scans is a second value larger than the first value.

An image processing apparatus for generating print data used in each of K relative scans performed on a unit area on a print medium by a print head for discharging ink, the print data determining discharge or non-discharge of ink to each pixel area corresponding to a plurality of pixels in the unit area, the image processing apparatus comprising:

• a first acquisition unit configured to acquire x image data sets that correspond to an image to be printed in the unit area and that determine an attribute of each of the plurality of pixels in the image and discharge or non-discharge of ink to each of the plurality of pixels;
• and
• a generation unit configured to generate the print data based on the x image data sets acquired by the first acquisition unit, and K mask patterns that correspond to the K scans of the unit area and that determine allowing or disallowing ink to be discharged in accordance with the attribute and discharge or non-discharge indicated at each of the plurality of pixels by the image data, wherein
• first print permitting pixels allowing ink to be discharged when the attribute indicated by the image data is a first attribute, and second print permitting pixels allowing ink to be discharged when the attribute indicated by the image data is a second attribute different from the first attribute are placed in the K mask patterns such that (i) a difference between a number of the first print permitting pixels placed in J (1<J<K) mask patterns corresponding to J scans from the first scan to the J-th scan among the K scans and the number of the first print permitting pixels placed in K−J mask patterns corresponding to K−J scans from the J+1-th scan to the K-th scan among the K scans is a first value, and (ii) a difference between a number of the second print permitting pixels placed in the J mask patterns corresponding to the J scans and the number of the second print permitting pixels placed in the K−J mask patterns corresponding to the K−J scans is a second value larger than the first value, and
• the generation unit generates the print data by using x mask pattern groups formed by dividing the K mask patterns, to each of which K/x mask patterns belong, associating the x mask pattern groups with the x image data sets acquired by the first acquisition unit.

An image processing method for generating print data used in each of K relative scans performed on a unit area on a print medium by a print head for discharging ink, the print data determining discharge or non-discharge of ink to each pixel area corresponding to a plurality of pixels in the unit area, the image processing method comprising:

• acquiring image data that corresponds to an image to be printed in the unit area and that determines an attribute of each of the plurality of pixels in the image and a number of discharges of ink from zero to N (N≧1) to each of the plurality of pixels;
• and
• generating the print data based on the image data acquired, and K mask patterns that correspond to the K scans of the unit area and that determine allowing or disallowing ink to be discharged in accordance with the attribute and number of discharges indicated at each of the plurality of pixels by the image data, wherein
• first print permitting pixels and second print permitting pixels are placed in the K mask patterns such that (i) a difference between a number of the first print permitting pixels placed in J (1<J<K) mask patterns corresponding to J scans from the first scan to the J-th scan among the K scans and the number of the first print permitting pixels placed in K−J mask patterns corresponding to K−J scans from the J+1-th scan to the K-th scan among the K scans is a first value, and (ii) a difference between a number of the second print permitting pixels placed in the J mask patterns corresponding to the J scans and the number of the second print permitting pixels placed in the K−J mask patterns corresponding to the K−J scans is a second value larger than the first value, the first print permitting pixels allowing ink to be discharged when the attribute is a first attribute and the number of discharges is M (1≦M≦N), the attribute and number of discharges being indicated by the image data, and disallowing ink to be discharged when the attribute is the first attribute and the number of discharges is M−1, the attribute and number of discharges being indicated by the image data, the second print permitting pixels allowing ink to be discharged when the attribute is a second attribute different from the first attribute and the number of discharges is M, the attribute and number of discharges being indicated by the image data, and disallowing ink to be discharged when the attribute is the second attribute and the number of discharges is M−1, the attribute and number of discharges being indicated by the image data.

An image processing method for generating print data used in each of K relative scans performed on a unit area on a print medium by a print head for discharging ink, the print data determining discharge or non-discharge of ink to each pixel area corresponding to a plurality of pixels in the unit area, the image processing method comprising:

• acquiring x sets of image data that is first image data corresponding to an image to be printed in the unit area and that determines an attribute of each of the plurality of pixels in the image and discharge or non-discharge of ink to each of the plurality of pixels;
• and
• generating the print data based on the x image data sets acquired, and K mask patterns that correspond to the K scans of the unit area and that determine allowing or disallowing ink to be discharged in accordance with the attribute and discharge or non-discharge indicated at each of the plurality of pixels by the image data, wherein
• first print permitting pixels and second print permitting pixels are placed in the K mask patterns such that (i) a difference between a number of the first print permitting pixels placed in J (1<J<K) mask patterns corresponding to J scans from the first scan to the J-th scan among the K scans and the number of the first print permitting pixels placed in K−J mask patterns corresponding to K−J scans from the J+1-th scan to the K-th scan among the K scans is a first value, and (ii) a difference between a number of the second print permitting pixels placed in the J mask patterns corresponding to the J scans and the number of the second print permitting pixels placed in the K−J mask patterns corresponding to the K−J scans is a second value larger than the first value, the first print permitting pixels allowing ink to be discharged when the attribute indicated by the image data is a first attribute, the second print permitting pixels allowing ink to be discharged when the attribute indicated by the image data is a second attribute different from the first attribute, and
• the print data is generated by using x mask pattern groups formed by dividing the K mask patterns, to each of which K/x mask patterns belong, associating the x mask pattern groups with the x image data sets acquired.