Pulse width modulator for a printing device
AssigneeMarvell International Ltd.
InventorsJohn D. Marshall, Douglas G. Keithley, Richard D. Taylor
Life of this patent
Estimating the term…
Abstract
A pulse width modulation technique is disclosed for use in an image forming device such as a laser printer or a photocopier. The technique implements a pacer to synthesize the frequency of a serializer circuit by stretching (or shrinking) pixel pulse train data. The pacer stretches the pixel pulse train data in accord with increment data that is based upon information about the image forming device, such as the number of bits in the pixel pulse train data, the number of bits in print engine pulse train, the target print engine frequency, and the serializer frequency. The technique can be implemented with digital circuits that provide digital test data.
Claims55
An apparatus comprising:
- a first device configured to generate a pixel pulse train;
- an increment value processor configured to calculate increment value data to compensate for a pace of a laser beam moving along a scan line that is not in sync with a frequency of the pixel pulse train, wherein the increment value data is associated with a group of bits from the pixel pulse train and is calculated from a target print engine frequency and a serializer frequency;
- and
- a second device configured to generate a print engine pulse train by adjusting the group of bits from the pixel pulse train using the increment value data to compensate, at least in part, for the pace of the laser beam moving along the scan line.
An apparatus comprising:
- means for generating a pixel pulse train;
- means for calculating increment value data to compensate for a pace of a laser beam moving along a scan line that is not in sync with a frequency of the pixel pulse train, wherein the increment value data is associated with a group of bits from the pixel pulse train and is calculated from a target sprint engine frequency and a serializer frequency;
- and
- means for generating a print engine pulse train by adjusting the group of bits from the pixel pulse train using the increment value data to compensate, at least in part, for the pace of the laser beam moving along the scan line.
A method comprising:
- generating a pixel pulse train;
- calculating, by a hardware processor, increment value data configured to compensate for a varying pace of a laser beam moving along a scan line that is not in sync with a frequency of the pixel pulse train, wherein the increment value data is associated with a group of bits from the pixel pulse train and is calculated from a target print engine frequency and a serializer frequency;
- and
- generating a print engine pulse train by adjusting the group of bits from the pixel pulse train based on the increment value data to compensate, at least in part, for the pace of the laser beam moving along the scan line.
A non-transitory storage medium having processor executable instructions that, when executed by a processor are configured to:
- generate a pixel pulse train;
- calculate increment value data operable to correct variations in a pace of a laser beam moving along a scan line that is not in sync with a frequency of the pixel pulse train, wherein the increment value data is associated with a group of bits from the pixel pulse train and is calculated from a target print engine frequency and a serializer frequency;
- and
- generate a print engine pulse train by adjusting a number of the group of bits from the pixel pulse train based on the increment value data to compensate, at least in part, for the pace of the laser beam moving along the scan line.
Dependencies are inferred from the claim text.