Image processing apparatus, image forming apparatus, and control method thereof

An image processing apparatus which outputs a dot pattern to an image forming apparatus that forms an image by scanning a printing head, comprising a plurality of printing elements, on a printing medium, comprising:

• an input unit adapted to input image data;
• a calculation unit adapted to calculate printing amounts for the respective printing elements for each main scan of the printing head in accordance with the image data;
• and
• an N-ary unit adapted to generate a dot pattern to be formed by applying N-ary processing (N is an integer not less than 2) to the printing amounts calculated by the calculation unit based on predetermined constraining condition information,
• wherein the constraining condition information is set so that a phase of the dot pattern to be generated by the N-ary unit has an opposite phase relationship in a low frequency region with respect to a dot pattern already printed on an identical region on the printing medium.

A method of controlling an image forming apparatus which forms an image by scanning a printing head, comprising a plurality of printing elements, on a printing medium, comprising:

• an input step of causing an input unit to input image data;
• a calculation step of causing a calculation unit to calculate printing amounts for the respective printing elements for each main scan of the printing head in accordance with the image data;
• and
• an N-ary step of causing an N-ary unit to generate a dot pattern to be formed by applying N-ary processing (N is an integer not less than 2) to the printing amounts calculated in the calculation step based on predetermined constraining condition information,
• wherein the constraining condition information is set so that a phase of the dot pattern to be generated by the N-ary unit has an opposite phase relationship in a low frequency region with respect to a dot pattern already printed on an identical region on the printing medium.

A method of controlling an image processing apparatus which outputs a dot pattern to an image forming apparatus that forms an image by scanning a printing head, comprising a plurality of printing elements, on a printing medium, comprising:

• an input step of causing an input unit to input image data;
• a calculation step of causing a calculation unit to calculate printing amounts for the respective printing elements for each main scan of the printing head in accordance with the image data;
• and
• an N-ary step of causing an N-ary unit to generate a dot pattern to be formed by applying N-ary processing (N is an integer not less than 2) to the printing amounts calculated in the calculation step based on predetermined constraining condition information,
• wherein the constraining condition information is set so that a phase of the dot pattern to be generated by the N-ary unit has an opposite phase relationship in a low frequency region with respect to a dot pattern already printed on an identical region on the printing medium.