Reduced memory usage for delay buffer during printing swaths in an inkjet printer

1. A method of printing swath of an image, comprising:

(a) calculating, a minimum number of passes P required to print the image using the equation P=(H i *V i )/(H s *V s ), wherein H i equals horizontal resolution of the image, V i equals vertical resolution of the image, H s equals horizontal resolution of the swath, and V s equals vertical resolution of the swath;

(b) allocating a memory space equal to N*S*(P+1)/2 for a delay buffer, wherein N equals number of nozzles in a color bank and S equals horizontal swath resolution;

(c) dividing the delay buffer into g segments having a first segment, a second segment, a (g−1) th segment, and a g th segment, wherein g=P(P+1)/2, such that, size of each of g segment equals (N/P)*S;

(d) receiving (N/P)*D raster lines splitting the raster lines into P color layers having a first color layer for a first pass, a second color layer for a second pass, a (P−1) th color layer for a (P−1) th pass, and a P th color layer for a P th pass, wherein D equals V i /V s ;

(e) searching for empty segments from g segments of the delay and grouping the empty segment into a first empty segment, a second empty segment, a (P−1) th empty segment and a P th empty segment;

(f) storing the first color layer for the first pass in the first segment, the second color layer for the second pass in the second empty segment, the (P−1) th color layer for the (P−1) th pass in (P−1) th empty segment, and the P th color layer for the P th pass in the P th empty segment;

(g) building an i th swath using segments having color layers for i th pass, and printing the i th swath, wherein, i equals 1, 2, P;

(h) emptying the segment having the color layer for the i th pass;

(i) advancing the print media and checking for incoming raster lines; and

(j) repeating steps (d) to (i) upon determining the incoming raster lines.

2. The method of claim 1 , wherein the empty segments are a subset of g segments available for reuse to store the layers.

3. The method of claim 1 , wherein the color layers for a printing pass are stored in less than P segment when the delay buffer is not full.

4. The method of claim 1 , wherein the color layers for a printing pass are stored in P segments when the delay buffer is full.

5. The method of claim 1 , wherein each time at least P segments of the delay buffer are available for storing the color layers.

6. A method of printing swaths of an image, comprising:

(a) calculating, a minimum number of passes P required to print the image using the equation P=(H i *V i )/(H s *V s ), wherein, H i equals horizontal resolution of the image, V i equals vertical resolution of the image, H s equals horizontal resolution of the swath, and V s equals vertical resolution of the swath;

(b) allocating a memory space equal to N*S*(P−1)/2 for a delay buffer, wherein N equals number of nozzles in a color bank and S equals horizontal swath resolution;

(c) dividing the delay buffer into g segments having a first segment, a second segment, a (g−1) th segment, and a g th segment, wherein g=P(P−1)/2, such that, size of each of g segment equals (N/P)*S;

(d) receiving incoming raster lines and splitting the raster lines into P color layers having a first color for a first pass, a second color layer for a second pass, a (P−1) th color layer for a (P−1) th pass, and a P th color layer for a P th pass;

(e) searching for empty segment from g segments of the delay buffer and grouping the empty segments into a first empty segment, a second empty segment, and a (P−1) th empty segment, and storing P−1 color layers in the empty segments without storing the color layers for i th pass, wherein i equals 1, 2, P;

(f) converting the i th color layers of the incoming raster lines into partial swath for the i th pass;

(g) repeating steps (d), (e) and (f) for (N/P)/8 times until a full swath is built for the i th pass, and printing the full swath;

(h) building a next partial swath using segments having color layers for (i+1) th pass;

(i) emptying the segments having the color layers for the (i+1) th pass;

(j) advancing a print media and checking for incoming raster lines; and

(k) repeating steps (d) to (j) upon determining the incoming raster lines.

7. The method of claim 6 , wherein each time 8*D raster lines are processed from the incoming raster lines prior to splitting the incoming raster lines into P color layers, where D equals V i /V s .

8. The method of claim 6 , wherein each time 8 color layers are converted into partial swath for the i th pass.

9. The method of claim 6 , wherein the empty segments are a subset of g segment from bottom to top the delay buffer available for reuse to store the color layers.

10. The method of claim 6 , wherein the color layers for a printing pass are stored in less than P−1 segments when the delay buffer is not full.

11. The method of claim 6 , wherein the color layers for a printing pass are stored in P−1 segments when the delay buffer is full.

12. The method of claim 6 , wherein each time at least (P−1) segments of the delay buffer are available for storing the color layers.

13. An inkjet printer, comprising:

a printhead having a plurality of nozzles arranged in at least one vertical column, wherein the nozzle is capable of selectively ejecting droplets of ink on a print media to form swath of an image;

a printhead carrier capable of mounting and carrying the printhead;

a carrier drive unit enabling the movement of the printhead carrier across the print media;

a feed roller unit capable of advancing the print media during imaging; and

a controller communicatively coupled to the printhead, the printhead carrier, the carrier drive unit and the feed roller unit, the controller having programmable instruction for performing a method, comprising;

(a) calculating a minimum number of passes P required to print the image using the equation P=(H i *V i )/(H s *V s ), wherein, H i equals horizontal resolution of the image, V i equals vertical resolution of the image, H s equals horizontal resolution of the swath, and V s equals vertical resolution of the swath;

(b) allocating a memory space equal to N*S*(P+1)/2 for a delay buffer, wherein N equals number of nozzles in a color bank and S equals horizontal swath resolution;

(c) dividing the delay buffer into g segment a first segment, a second segment, a (g−1) th segment, and a g th segment, wherein g=P(P+1)/2, such that, size of each of g segment equals (N/P)*S;

(d) receiving (N/P)*D raster lines and splitting the raster lines into P color layers having a first color layer for a first pass, a second color layer for a second pass, a (P−1) th color layer for a (P−1) th pass, and a P th color layer for a P th pass, wherein D equals V i /V s ;

(e) searching for empty segments from g segments of the delay and grouping the empty segment into a first empty segment, a second empty segment, a (P−1) th empty segment, and a P th empty segment;

(f) storing the first color layer for the first pass in the first segment, the second color layer for the second pass in the second empty segment, the (P−1) th color layer for the (P−1) th pass in (P−1) th empty segment, and the P th color layer for the P th pass in the P th empty segment;

(g) building an i th swath using segments having color layers for i th pass, and printing the i th swath, wherein, i equals 1, 2, P;

(h) emptying the segment having the color layers for the i th pass;

(i) advancing the print media and checking for incoming raster lines; and

(j) repeating steps (d) to (i) upon determining the incoming raster lines.

14. The inkjet of claim 13 , wherein the inkjet printer is communicatively coupled to a host computer with a memory having printing driver capable of sending an image data of the image in the form of consecutive raster lines to the controller.

15. The inkjet printer of claim 14 , wherein the controller comprises a formatter capable of generating a swath data based on the image data transferred from the host computer.

16. The inkjet printer of claim 13 , wherein the nozzles are capable of depositing dots of cyan, magenta, and yellow ink in a combination such that at least black color, blue color, red color, green color, magenta color, cyan color, yellow color, and white color are produced.

17. An inkjet printer, comprising:

A printhead having a plurality of nozzles arranged in at least one vertical column, wherein the nozzle is capable of selectively ejecting droplets of ink on a print media to form swath of an image;

a printhead carrier capable of mounting and carrying the printhead;

a carrier drive unit enabling the movement of the printhead carrier the print media;

a feed roller unit capable of advancing the print media during imaging; and

a controller communicatively coupled to the printhead, the printhead carrier, the carrier drive unit and the feed roller unit, the controller having programmable instructions for performing a method, comprising:

(a) calculating, a minimum number of passes P required to print the image using the equation P=(H i *V i )/(H s *V s ), wherein, H i equals horizontal resolution of the image, V i equals vertical resolution of the image, H s equals horizontal resolution of the swath, and V s equals vertical resolution of the swath;

(b) allocating a memory space equal to N*S*(P−1)/2 for a delay buffer, wherein N equals number of nozzles in a color bank and S equals horizontal swath resolution;

(c) dividing the delay buffer into g segments having a first segment, a second segment, a (g−1) th segment, and a g th segment, wherein g=P(P−1)/2, such that, size of each of g segment equals (N/P)*S;

(d) receiving incoming raster lines and splitting the raster lines into P color layers having s first color layer for a first pass, a second color layer for a second pass, a (P−1) th color layer for a (P−1) th pass, and a P th color layer for P th pass;

(e) searching for empty segments from g segments of delay buffer and grouping the empty segment into a first empty segment, a second empty segment, and a (P−1) th empty segment, and storing P−1 color layers in the empty segments without storing the color layers for i th pass, wherein i equals 1, 2, P;

(f) converting the i th color layers of the incoming raster lines into partial swath for the i th pass;

(g) repeating steps (d), (e) and (f) for (N/P)/8 times until a full swath is built for the i th pass, and printing the full swath;

(h) building a next partial swath using segments having color layers for (i+1) th pass;

(i) emptying the segments having the color layers for the (i+1) th pass;

(j) advancing a print media and checking for incoming raster line; and

(k) repeating steps (d) to (j) upon determining the incoming raster lines.

18. The inkjet printer of claim 17 , wherein the inkjet printer is communicatively coupled to a host computer with a memory having printer driver capable of sanding an image data of the image in the form of consecutive raster lines to the controller.

19. The inkjet printer of claim 18 , wherein the controller comprises a formatter capable of generating a swath data based on the image data transferred from the host computer.

20. The inkjet of claim 17 , wherein the nozzles are capable of depositing dots of cyan, magenta, and yellow ink in a combination such that at least black color, blue color, red color, green color, magenta color, cyan color, yellow color, and white color are produced.