Image information processing apparatus and method

An image processing apparatus comprising:

• input means for inputting image signals for a plurality of color components constituting a color image;
• and
• modulation means for generating pulse-width modulation signals by performing pulse-width modulation based on said image signals for the respective color components,
• wherein pulse-width modulation signals, which can be generated by said modulation means, having maximum pulse widths determined for the respective color components are different from each other for the respective color components, and pulse-width modulation signals, which can be generated by said modulation means, having minimum pulse widths determined for the respective color components are approximately equal to each other for the respective color components, and
• wherein the maximum pulse widths for the respective color components are pulse widths of the pulse-width modulation signals when a respective density level of the image signals is at a maximum level, and the minimum pulse widths for the respective color components are pulse widths of the pulse-width modulation signals when a respective density level of the image signals is at a minimum level.

An image processing apparatus comprising:

• input means for inputting a first color component signal and a second color component signal constituting a color image signal;
• and
• pulse-width modulation signal generation means for generating pulse-width modulation signals by respectively comparing said first and second color component signals with a pattern signal of a predetermined period,
• wherein the relative relation between said pattern signal and said first color component signal is different from that between said pattern signal and said second color component signal such that said pulse-width modulation signals generated by said pulse-width modulation signal generation means, have different maximum pulse widths for said first color component and said second color component and have approximately the same minimum pulse widths for said first color component and said second color component, and
• wherein the maximum pulse widths for the first and second color components are pulse widths of the pulse-width modulation signals when a respective density level of said first and second color component signals is at a maximum level, and the minimum pulse widths for the first and second color components are pulse widths of the pulse-width modulation signals when a respective density level of said first and second color component signals is at a minimum level.

An image processing method comprising:

• a pulse width modulation step of generating a pulse signal having a pulse width corresponding to input image data by performing pulse width modulation based on the image data;
• and
• a change step of changing a maximum pulse width of the pulse signal, which can be outputted in accordance with an image processing mode without changing a minimum pulse width of the pulse signal in any image processing mode,
• wherein the maximum pulse width is a pulse width of the pulse signal generated in said pulse-width modulation step when a density level of the input image data is at a maximum level, and the minimum pulse is a pulse width of the pulse signal generated in said pulse-width modulation step when a density level of the input image data is at a minimum level.

An image processing method comprising:

• an input step of inputting image signals for a plurality of color components constituting a color image;
• and
• a modulation step of generating pulse-width modulation signals by performing pulse-width modulation based on said image signals for the respective color components,
• wherein at said modulation step, pulse-width modulation signals having maximum pulse widths determined for the respective color components are different from each other for the respective color components, and pulse-width modulation signals having minimum pulse widths determined for the respective color components are approximable equal to each other for the respective color components, and
• wherein at said modulation step, the maximum pulse widths for the respective color components are pulse widths of the pulse-width modulation signals when a respective density level of the input image signals is at a maximum level, and the minimum pulse widths for the respective color components are pulse widths of the pulse-width modulation signals when a respective density level of the image signals is at a minimum level.

An image processing method comprising:

• an input step of inputting a first color component signal and a second color component signal constituting a color image signal;
• and
• a pulse-width modulation signal generation step of generating pulse-width modulation signals by respectively comparing said first and second color component signals with a pattern signal of a predetermined period,
• wherein the relative relation between said pattern signal and said first color component signal is different from that between said pattern signal and said second color component signal such that said pulse-width modulation signals generated at said pulse-width modulation signal generation step, have different maximum pulse widths for said first color component and have approximately the same minimum pulse widths for said first color component and said second color component, and
• wherein the maximum pulse widths for the first and second color components are pulse widths of the pulse-width modulation signals when a respective density level of the first and second color component signals is at a maximum level, and the minimum pulse widths for the first and second color components are pulse widths of the pulse-width modulation signals when a respective density level of said first and second color component signals is at a minimum level.