Printing method and apparatus

A printing method of printing on a printing medium, comprising:

• generating dot data representing a status of dot formation on each of print pixels of a print image to be formed on the printing medium, by performing a halftone process on image data representing an input tone value of each of pixels constituting an original image;
• and
• generating the print image with a print head by mutually combining a plurality of dot groups being formed in each scan of the print head in response to the dot data, wherein
• the generating dot data comprises setting a condition for the halftone process for reducing contact between dot groups formed consecutively by a plurality of temporally consecutive scan passes within at least part of tone values, wherein
• the generating dot data comprises determining a state of dot formation by diffusing error into neighboring pixels, the neighboring pixels being print pixels neighboring a targeted pixel targeted for decision of the state of dot formation and for which the state of dot formation is undecided;
• and wherein
• the diffusing error includes increasing the diffusing error into pixels belonging to a specific pixel group among the neighboring pixels, the specific pixel group being for which the at least two consecutively formed dot groups are formed.

A printing apparatus for printing on a printing medium, comprising:

• a dot data generator that generates dot data representing a status of dot formation on each of print pixels of a print image to be formed on the print medium, by performing a halftone process on image data representing an input tone value of each of pixels constituting an original image;
• and
• a print image generator having a print head and generating the print image with a print head by mutually combining a plurality of dot groups in a common print area, each of the plurality of dot groups being formed in each scan of the print head in response to the dot data, wherein
• the dot data generator is configured such that a condition for the halftone process is set for reducing contact between dot groups formed consecutively by a plurality of temporally consecutive scan passes within at least part of tone values, wherein
• the halftone process condition is set such that a prescribed mixed pattern composed of at least two consecutively formed dot groups has prescribed spatial frequency characteristics.