Printing by switching sub-scan feeding between monochromatic and color areas

A printing method comprising the steps of:

• providing a print head having
• a plurality of single chromatic nozzle groups for ejecting mutually different chromatic inks, each consisting of plurality of nozzles, and
• an achromatic nozzle group for ejecting achromatic ink consisting of a greater number of nozzles than each of the single chromatic nozzle groups;
• and
• printing images in a monochromatic area on a printing medium with the achromatic ink alone, and in a color area with the chromatic inks, the step of printing images comprising the steps of:
• (a) executing regular color mode printing whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the color area;
• (b) executing lower-edge color mode printing whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area;
• (c) executing upper-edge monochromatic mode printing whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area;
• and
• (d) executing regular monochromatic mode printing whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area.

A printing apparatus which prints images in a monochromatic area on a printing medium with an achromatic ink alone, and in a color area with chromatic inks, by ejecting ink drops from a nozzle to deposit the ink drops on the printing medium to form dots, comprising:

• a printing head having:
• a plurality of single chromatic nozzle groups for ejecting mutually different chromatic inks each consisting of plurality of nozzles, and
• an achromatic nozzle group for ejecting achromatic ink consisting of a greater number of nozzles than each of the single chromatic nozzle groups;
• a main scan drive unit that moves at least one of the printing head and the printing medium to perform main scanning;
• a sub-scan drive unit that moves at least one of the printing head and the printing medium in a direction that intersects a main scanning direction to perform sub-scanning;
• and
• a control unit that controls the printing head, the main scan drive unit and the sub-scan drive unit,
• wherein the control unit has:
• (a) a regular monochromatic mode unit that executes regular monochromatic mode printing whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area;
• (b) a lower-edge monochromatic mode unit that executes lower-edge monochromatic mode printing whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area;
• (c) a upper-edge color mode unit that executes upper-edge color mode printing whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area;
• and
• (d) a regular color mode unit that executes regular color mode printing whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the color area.

A printing apparatus which prints images in a monochromatic area on a printing medium with an achromatic ink alone, and in a color area with chromatic inks, by ejecting ink drops from a nozzle to deposit the ink drops on the printing medium to form dots, comprising:

• a printing head having:
• a plurality of single chromatic nozzle groups for ejecting mutually different chromatic inks, each consisting of plurality of nozzles, and
• an achromatic nozzle group for ejecting achromatic ink consisting of a greater number of nozzles than each of the single chromatic nozzle groups;
• a main scan drive unit that moves at least one of the printing head and the printing medium to perform main scanning;
• a sub-scan drive unit that moves at least one of the printing head and the printing medium in a direction that intersects a main scanning direction to perform sub-scanning;
• and
• a control unit that controls the printing head, the main scan drive unit and the sub-scan drive unit,
• wherein the control unit has:
• (a) a regular color mode unit that executes regular color mode printing whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the color area;
• (b) a lower-edge color mode unit that executes lower-edge color mode printing whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area;
• (c) a upper-edge monochromatic mode unit that executes upper-edge monochromatic mode printing whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area;
• and
• (d) a regular monochromatic mode unit that executes regular monochromatic mode printing whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area.

A computer program product for printing images in a monochromatic area on a printing medium with the achromatic ink alone, and in a color area with the chromatic inks, using a computer, the computer being connected with a printing device having a printing head equipped with

• a plurality of single chromatic nozzle groups for ejecting mutually different chromatic inks, each consisting of plurality of nozzles, and
• an achromatic nozzle group for ejecting achromatic ink consisting of a greater number of nozzles than each of the single chromatic nozzle groups, the computer program product comprising:
• a computer readable medium;
• and
• a computer program stored on the computer readable medium, the computer program comprising:
• (a) a regular monochromatic mode program for causing the computer to execute regular monochromatic mode printing whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area;
• (b) a lower-edge monochromatic mode program for causing the computer to execute lower-edge monochromatic mode printing whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area;
• (c) a upper-edge color mode program for causing the computer to execute upper-edge color mode printing whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area;
• and
• (d) a regular color mode program for causing the computer to execute regular color mode printing whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the color area.

A computer program product for printing images in a monochromatic area on a printing medium with the achromatic ink alone, and in a color area with the chromatic inks, using a computer, the computer being connected with a printing device having a printing head equipped with

• a plurality of single chromatic nozzle groups for ejecting mutually different chromatic inks, each consisting of plurality of nozzles, and
• an achromatic nozzle group for ejecting achromatic ink consisting of a greater number of nozzles than each of the single chromatic nozzle groups, the computer program product comprising:
• a computer readable medium;
• and
• a computer program stored on the computer readable medium, the computer program comprising:
• (a) a regular color mode program for causing the computer to execute regular color mode printing whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the color area;
• (b) a lower-edge color mode program for causing the computer to execute lower-edge color mode printing whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area;
• (c) a upper-edge monochromatic mode program for causing the computer to execute upper-edge monochromatic mode printing whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area;
• and
• (d) a regular monochromatic mode program for causing the computer to execute regular monochromatic mode printing whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area.