Color printer and control method thereof with pulse width modulation for tone control based on type of document and number of colors printed

A color printing apparatus having a pulse-width-modulation means which performs pulse-width modulation for tone control comprising:

• first determination means for determining whether a printing mode of printing data supplied is a CAD mode that places great value on thin line reproducibility;
• second determination means for determining whether the printing data is to be processed as color data;
• and
• setting means for setting a pulse-width-modulation pattern to be used by said pulse-width-modulation means in accordance with determination results obtained by said first and second determination means,
• wherein said setting means sets a first pulse-width-modulation pattern when said first determination means determines that the printing mode of the printing data is not the CAD mode or when said second determination means determines that the printing data is not to be processed as color data, and wherein said setting means sets a second pulse-width-modulation pattern having a smaller developer adhesion amount than the first pulse-width-modulation pattern, when said first determination means determines that the printing mode is the CAD mode and in addition said second determination means determines that the printing data is to be processed as color data.

A color printing method, comprising printing using a signal output by a pulse-width-modulation means which performs pulse-width-modulation for tone control, wherein the pulse-width-modulation means performs:

• a first determination step, of determining whether a printing mode of printing data supplied is a CAD mode that places great value on thin line reproducibility;
• a second determination step, of determining whether the printing data is to be processed as color data;
• and
• a setting step, of setting a pulse-width-modulation pattern to be used by the pulse-width-modulation means in accordance with determination results obtained in said first and second determination steps,
• wherein said setting step includes setting a first pulse-width-modulation pattern when it is determined in said first determination step that the printing mode of the printing data is not the CAD mode or when it is determined in said second determination step that the printing data is not to be processed as color data, and wherein said setting step includes setting a second pulse-width-modulation pattern having a smaller developer adhesion amount than the first pulse-width-modulation pattern, when it is determined in said first determination step that the printing mode is the CAD mode and in addition it is determined in said second determination step that the printing data is to be processed as color data.

A computer-readable medium, storing, in executable form, program code for causing a computer to perform a color printing method, comprising printing using a signal output by a pulse-width-modulation means which performs pulse-width-modulation for tone control, wherein the program code causes the pulse-width-modulation means to perform:

• a first determination step, of determining whether a printing mode of printing data supplied is a CAD mode that places great value on thin line reproducibility;
• a second determination step, of determining whether the printing data is to be processed as color data;
• and
• a setting step, of setting a pulse-width-modulation pattern to be used by the pulse-width-modulation means in accordance with determination results obtained said first and second determination steps,
• wherein said setting step includes setting a first pulse-width-modulation pattern when it is determined in said first determination step that the printing mode of the printing data is not the CAD mode or when it is determined in said second determination step that the printing data is not to be processed as color data, and wherein said setting step includes setting a second pulse-width-modulation pattern having a smaller developer adhesion amount than the first pulse-width-modulation pattern, when it is determined in said first determination step that the printing mode is the CAD mode and in addition it is determined in said second determination step that the printing data is to be processed as color data.