Laser print apparatus with dual halftones

• US 20060087695A1
• Filed: 10/27/2004
• Published: 04/27/2006
• Est. Priority Date: 10/27/2004
• Status: Active Grant

• Current Assignee: Marvell International Technology, Ltd. (Marvell Technology Group Limited)
• Original Assignee: Marvell International Technology, Ltd. (Marvell Technology Group Limited)
• Inventors: Shoen, Jay R., Keithley, Douglas Gene
• Granted Patent: US 7,733,532 B2
• Time in Patent Office: Days
• US Class Current: 358/3.60
• CPC Class Codes: G06K 15/1881 Halftoning halftoning of still images in general H04N1/405, H04N1/52
• CPC Class Codes: H04N 1/40068 Modification of image resolution, i.e. determining the values of picture elements at new relative positions H04N1/3935 takes precedence
• CPC Class Codes: H04N 1/40081 Soft dot halftoning, i.e. producing halftone dots with gradual edges

Abstract

A printing system comprises a memory configured to store image data representing an image. The printing system comprises a processor configured to perform a first digital halftone process on a first portion of the image and a second digital halftone process on a second portion of the image.

Claims

1. A printing system comprising:

a memory configured to store image data representing an image; and

a processor configured to perform a first digital halftone process on a first portion of the image and a second digital halftone process on a second portion of the image.

2. The printing system of claim 1, wherein the first portion is an edge of the image and the second portion is not an edge of the image.

3. The printing system of claim 2, wherein the processor is configured to locate the first portion by comparing intensity values of adjacent pixels in the image.

4. The printing system of claim 2, wherein the first digital halftone process comprises a higher lines per inch (lpi) halftone than the second digital halftone process.

5. The printing system of claim 2, wherein the first digital halftone process comprises a halftone within a range of approximately 200 lines per inch (lpi) to approximately 300 lpi.

6. The printing system of claim 2, wherein the second digital halftone process comprises a halftone within a range of approximately 100 lines per inch (lpi) to approximately 150 lpi.

7. The printing system of claim 2, wherein the first digital halftone process approximates edge pixel values by semi-randomly alternating between two pixel values.

8. The printing system of claim 2, wherein the first portion is at least one pixel wide.

9. A printing system comprising:

a memory configured to store image data; and

a processor configured to locate image edges in the image data and apply a first halftone to image data that is located at image edges and apply a second halftone to image data that is not located at image edges.

10. The printing system of claim 9, wherein the processor is configured to locate image edges by comparing intensity values of adjacent pixels in the image data.

11. The printing system of claim 9, further comprising:

a laser print engine for printing the image data.

12. The printing system of claim 9, wherein the first halftone comprises a higher lines per inch (lpi) than the second halftone.

13. A method for printing an image, the method comprising:

receiving image data;

locating first image portions comprising edges and second image portions not comprising edges in the image data;

applying a first halftone to the first image portions;

applying a second halftone to the second image portions; and

printing the image data with the applied first halftone and the applied second halftone.

14. The method of claim 13, wherein locating first image portions comprises comparing intensity values of adjacent pixels in the image data.

15. The method of claim 13, wherein applying the first halftone comprises applying a halftone having a higher lines per inch (lpi) than the second halftone.

16. The method of claim 13, wherein applying the first halftone comprises applying a halftone that approximates edge pixel values by semi-randomly alternating between two pixel values.

17. The method of claim 13, wherein applying the second halftone comprises applying a halftone within a range of approximately 100 lines per inch (lpi) to approximately 150 lpi.

18. The method of claim 13, wherein applying the first halftone comprises applying a halftone within a range of approximately 200 lines per inch (lpi) to approximately 300 lpi.

19. The method of claim 13, wherein receiving image data comprises receiving image data comprising text.

20. The method of claim 13, wherein receiving image data comprises receiving image data comprising graphics.