Method, system and program product for amplitude modulated multiple pel print quality enhancement

1. A method of printing an image using a printer, comprising:

for each subject pel of the image, determining a pulse amplitude value based on a pattern of surrounding pels;

using said pulse amplitude values from a pel region comprising a selected number of at least two adjacent subject pels to calculate a gray pulse amplitude applicable to each of the selected number of adjacent subject pels; and

using the gray pulse amplitude to generate an output pulse amplitude applicable to each pel in the pel region;

periodically configuring a pulse generator to produce a gray pulse having the gray pulse amplitude;

processing the pels in the pel region at a first data rate, wherein processing a pel includes:

selecting a pulse from a set of pulses wherein the set of pulses includes the gray pulse; and

generating the selected pulse as an output pulse;

wherein a frequency of said periodically configuring equals said first data rate divided by the selected number adjacent pels in the pel region.

2. The method of claim 1 wherein toner is attracted to a charged region corresponding to the pels in the pel region causing a portion of the image represented by the at least two adjacent subject pels to be printed as determined by the gray pulse amplitude.

3. The method of claim 1 wherein the surrounding pels of a subject pel form a rectangular grid with said subject pel at the center or near center.

4. The method of claim 1 wherein the surrounding pels of a subject pel form a diamond shaped grid with said subject pel at the center or near center.

5. The method of claim 1 wherein the determining of a pulse amplitude value for a subject pel comprises assigning a pre-defined pulse amplitude value corresponding to a pattern category into which the pattern of surrounding pels falls.

6. The method of claim 1 , wherein using the gray pulse amplitude to generate a pulse amplitude includes using position information to determine whether a pulse amplitude for a pel is a fully black amplitude, a fully white amplitude, or the gray pulse amplitude.

7. The method of claim 6 , wherein the pulse amplitude determined for a pel is the gray pulse amplitude if the pel is an “on” pel and either of its adjacent pels is an “off” pel.

8. The method of claim 1 , wherein the set of pulses consists of a white pulse having an amplitude suitable to produce an all-white pel, a black pulse having an amplitude suitable to produce an all-black pel, and the gray pulse.

9. A computer program product comprising computer executable instructions, stored on a computer readable medium, for printing an image with a printer, the instructions comprising instructions for:

modifying a first pulse amplitude value for a first subject pel based on a pattern of first surrounding pels;

modifying a second pulse amplitude value for a second subject pel based on a pattern of second surrounding pels, wherein the first and second subject pels are adjacent; and

using said modified first and second pulse amplitude values to calculate a combined amplitude value;

periodically providing an amplitude modulator with the combined amplitude value to enable the modulator to generate an output pulse, valid for the first pel as well as the second pet, the output pulse having an amplitude equal to the combined amplitude value, wherein a frequency of said periodic providing is half of a video data rate of the printer.

10. The computer program product of claim 9 , wherein the surrounding pels of a subject pel form a rectangular grid with said subject pel at the center or near center.

11. The computer program product of claim 9 , wherein the surrounding pels of a subject pel form a diamond shaped grid with said subject pel at the center or near center.

12. The computer program product of claim 9 , wherein the instructions for determining of a pulse amplitude value for a subject pel comprise instructions for assigning a pre-defined pulse amplitude value corresponding to a pattern category into which the pattern of surrounding pels falls.

13. The computer program product of claim 9 , wherein the instructions for determining a pulse amplitude value for a subject pel comprise instructions for assigning a pre-defined pulse amplitude value corresponding to the predefined pattern category into which the pattern of surrounding pels falls.

14. The computer program product of claim 9 , further comprising instructions for using position information to determine whether a pulse amplitude for a pel is a fully black amplitude, a fully white amplitude, or the combined pulse amplitude.

15. The computer program product of claim 14 , wherein the pulse amplitude determined for a pel is the combined pulse amplitude if the pel is an “on” pel and either of its adjacent pels is an “off” pel.

16. A printer system, comprising:

a raster processor for processing page description or vector graphics information of an image into pel data;

first control logic for processing each pel of the image, the processing comprising;

identifying a window of pels surrounding a subject pel;

determining an adjusted pulse amplitude value for the subject pel based on a pattern of said surrounding pels;

second control logic for processing at least two adjacent pels, the processing comprising using the adjusted pulse amplitude value of each of the at least two adjacent pels to:

calculate a combined complex amplitude peak power pulse to charge a region of a combined region of said at least two adjacent pels; and

determine position information indicating an alignment of said region within the combined region of said at least two adjacent pels; and

an amplitude modulator for processing input pulse amplitude and alignment information to create an output pulse to control a laser in charging an area of a rotating drum of a printer, wherein the pulse amplitude modulator produces said output pulses at a rate equal to a video data rate of the printer divided by the number of adjacent pels processed at a time by the second control logic wherein the second control logic delivers the combined complex amplitude peak pulse and alignment information to the pulse amplitude modulator.

17. The system of claim 16 , wherein said at least two adjacent pels consist of two adjacent pels.

18. The system of claim 16 , wherein said at least two adjacent pels consist of three adjacent pels.

19. The system of claim 16 , wherein the determining of an adjusted pulse amplitude value for a subject pel comprises assigning a pre-defined pulse amplitude value corresponding to a predefined pattern category into which the pattern of surrounding pels falls.

20. The system of claim 19 , further comprising a storage medium accessible to said first control logic and said second control logic and having stored therein at least one look up table encoding the combined pulse and position information to provide one set of combined pulse and position information for an input of:

said pulse amplitude value for each of said at least two adjacent pels; and

wherein said steps of calculating the combined pulse and determining position information comprise retrieving said combined pulse and position information from said at least one look up table.