US 11,052,671 B2
Image processing apparatus, image processing method, and inkjet printing apparatus
Hiroshi Kawafuji, Kawasaki (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Dec. 10, 2018, as Appl. No. 16/214,880.
Claims priority of application No. JP2017-241107 (JP), filed on Dec. 15, 2017.
Prior Publication US 2019/0184713 A1, Jun. 20, 2019
Int. Cl. B41J 2/21 (2006.01); G06K 15/10 (2006.01); B41J 2/52 (2006.01); H04N 1/405 (2006.01)
CPC B41J 2/2132 (2013.01) [B41J 2/52 (2013.01); G06K 15/102 (2013.01); G06K 15/107 (2013.01); H04N 1/4055 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An image processing apparatus generating ejection data for printing an image in a unit area of the print medium by repeating a printing scan and a conveyance operation alternately,
the printing scan being an operation of using a first nozzle array and a second nozzle array, each having a predetermined number of nozzles arrayed in a predetermined direction, the first nozzle array and the second nozzle array being arrayed in a direction intersecting the predetermined direction with nozzles of the first nozzle array corresponding in position in the predetermined direction with nozzles of the second nozzle array, and each nozzle being configured to eject the same kind of ink, and scanning the first nozzle array and the second nozzle array in a first scanning direction and a second scanning direction opposite to the first direction intersecting the predetermined direction while causing each nozzle to eject the ink toward the print medium,
the conveyance operation being an operation of conveying the print medium by a distance corresponding to each of M print regions obtained by dividing a predetermined number of nozzles of a nozzle array into M regions in the predetermined direction, M being an integer of four or more, in a conveying direction intersecting the direction of the printing scan,
the image in the unit area of the print medium being printed by M printing scans, and
the image processing apparatus comprising:
a column data generation unit configured to generate N pieces of column data that are binary dot data based on multi-level image data, N being an integer between four and M inclusive, such that some of the N pieces of column data indicates dot printing on the same pixel in a predetermined area of the print medium; and
an ejection data generation unit that generates ejection data for the first nozzle array using a first mask pattern that defines, in advance, print-permitted pixels at which dot-printing is permitted and print-not-permitted pixels at which dot-printing is not permitted with respect to the M print regions of the first nozzle array and the N pieces of column data, and generates ejection data for the second nozzle array using a second mask pattern, different from the first mask pattern, that defines, in advance, print-permitted pixels at which dot-printing is permitted and print-not-permitted pixels at which dot-printing is not permitted with respect to the M print regions of the second nozzle array and the N pieces of column data, so as to generate the ejection data for the first nozzle array and the ejection data for the second nozzle array, using different pieces of the column data of the N pieces of column data for respective different printing scans for the predetermined area of the print medium, and using the same pieces of the column data for the same printing scan,
wherein (i) a first part of the first mask pattern corresponding to at least one region of the M print regions of the first nozzle array used for one or more predetermined print scans in a first direction of the scanning direction for a first region and a first part of the second mask pattern corresponding to the at least one region of the M print regions of the first nozzle array used for the one or more predetermined print scans in the first direction for the first region have a complementary relationship,
(ii) a second part of the first mask pattern corresponding to another at least one region of the M print regions of the first nozzle array used for another predetermined print scan in the first direction for the first region and the first part of the first mask pattern have a complementary relationship, and
(iii) a second part of the second mask pattern corresponding to at least one region of the M print regions of the second nozzle array used in the one or more predetermined print scans in the first direction for the first region and the first part of the second mask pattern have a complementary relationship, and
wherein the ejection data generation unit generates the ejection data for the first nozzle array and the second nozzle array for the one or more predetermined print scans and the other scan in the first direction for the first region using the pieces of column data of the N pieces of column data which indicate dot forming on at least one same position.