Laser diode modulator and method of controlling laser diode modulator
AssigneeHewlett-Packard Development Company, L.P.
InventorsRodolfo Jodra, George Henry Kerby, Eugene A. Roylance
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Abstract
A method for adjusting a laser diode drive current pulse, comprises providing a power correction table comprising drive current pulse correction factors corresponding to counter positions. The method also comprises providing a jump table comprising counter position adjustments corresponding to correction factors. A count value of a position within the counter positions is maintained. Maintaining the count value comprises indexing the count value to the jump table and incrementing the count value for each of a series of pixel clocks. A correction factor is determined, wherein determining the current correction factor comprises indexing the count value to the power correction table.
Claims18
A method for adjusting a drive current pulse for a laser diode, comprising:
- providing a power correction table comprising drive current pulse correction factors corresponding to counter positions;
- providing a jump table comprising counter position adjustments corresponding to correction factors;
- maintaining a count value of a position within a counter, wherein maintaining the count value comprises indexing the count value to the jump table and incrementing the count value for each of a series of pixel clocks;
- and
- determining a correction factor, wherein determining the correction factor comprises indexing the count value to the power correction table.
An image forming system, comprising:
- a laser diode for exposing pixel areas for forming images with a nominal full pixel exposure;
- a current source for providing a drive current with a current magnitude to the laser diode;
- a switch for providing a drive current pulse with a duration to the laser diode;
- and
- a controller for controlling the current magnitude and the duration of the current pulse, wherein the controller comprises memory with a lookup table, wherein the lookup table includes correction factors for achieving nominal full pixel exposure indexed to corresponding pixel clock positions, and wherein the controller comprises processor executable instructions for maintaining a pixel count value and for determining a correction factor corresponding to the pixel count value.
An image forming system comprising:
- a drive current source;
- a switch;
- a controller for controlling the switch and drive current source to provide a current pulse having a current magnitude and a duration, wherein the controller provides modulation of at least one of the duration or current magnitude to achieve a nominal exposure responsive to the current pulse, wherein the modulation accounts for variations in laser diode output power during the pulse and variations in output power related to a final output power of a preceding pulse;
- and wherein the controller includes a digital lookup table comprising correction factors and the controller includes processor executable software for determining the correction factor to be applied to the current pulse.
Dependencies are inferred from the claim text.