Electrophotographic printer, and method of controlling light emitting elements in an electrophotographic print head

An electrophotographic printer configured to print lines of pixels on a print media, comprising:

• a print head having a predetermined number of light emitting elements;
• a predetermined number of pulse width modulators having different width output pulses, the predetermined number being less than the number of the light emitting elements;
• a processor configured to select which ones of the pulse width modulators should be coupled to which of the light emitting elements for each of the lines so as to compensate for variations in efficiencies between different ones of the light emitting elements;
• and
• a multiplexer coupled to the processor and controlled by the processor to couple the light emitting elements selected by the processor to respective ones of the pulse width modulators, the number of the light emitting elements coupled to one of the pulse width modulators being changed during use of the printer.

A system for controlling an electrophotographic print head including a plurality of light emitting elements, the system comprising:

• a predetermined number “x” of programmable pulse width modulators, the predetermined number being less than the number of the light emitting elements;
• means for, during preparations for printing a line, selecting the “x” most commonly required different pulse widths for the line;
• means for mapping those of the light emitting elements requiring the selected pulse widths to corresponding ones of the pulse width modulators;
• means for mapping remaining ones of the light emitting elements to the pulse width modulators having pulse widths close to required pulse widths for those of the light emitting elements;
• means for programming the pulse width modulators with the most commonly required different pulse widths for the line;
• and
• means for coupling each of the programmed pulse width modulators to multiple ones of the light emitting elements based on the mappings.