Color image forming apparatus

• US 6,067,377 A
• Filed: 09/20/1996
• Issued: 05/23/2000
• Est. Priority Date: 09/20/1995
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Hata, Hiroya
• Primary Examiner(s): NGUYEN, ANH-VINH THI
• Application Number:
  US08/717,327
• Time in Patent Office: 1,341 Days
• Field of Search: 382/162, 382/163, 382/165, 382/167, 382/190, 382/199, 382/201, 382/202, 382/203, 382/243, 382/257, 382/256, 382/258, 382/259, 382/274, 382/275, 382/266, 382/254, 382/255, 358/515, 358/516, 358/517, 358/518, 358/519, 358/520, 358/521, 358/461, 358/1.9, 358/1.6, 358/1.1
• US Class Current: 382/167
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence

Abstract

An image forming apparatus having a correcting function for preventing toner from scattering around edge portions of line images. The image forming apparatus includes an image paper sheet formed from an original image for testing, a line width extracting unit for reading the image paper sheet for correcting and color-by-color extracting a state of toner scattering around edge portions of the line image. Color-by-color correcting data is then calculated based on the color-by-color extracted information. A line width correcting unit accomplishes correction based on the calculated result when subsequently forming ordinary images.

Claims

1. A color image forming apparatus comprising:

an image paper sheet for compensation including a testing image generated from an original image for testing, the testing image including a line image;

a line width extracting means for reading color-by-color for a plurality of colors line widths of the testing image from the image paper sheet for compensation and extracting information of a state of toner scattering around edge portions of the line image;

calculating means for calculating color-by-color correcting data based on the color-by-color extracted information; and

line width cor recting means for correcting the toner scattering based on a result calculated by said calculating means for subsequent image forming operations.

2. A color image forming apparatus according to claim 1, further comprising an image storing memory storing said original image for testing.

3. A color image forming apparatus according to claim 2, wherein said original image for testing is a printed paper sheet for testing.

4. A color image forming apparatus according to claim 2, wherein said original image for testing is a recording medium storing code information.

5. A color image forming apparatus according to claim 1, wherein said line width correcting means reduces toner amount around edge portions of line images so as to prevent toner from scattering around the edge portions.

6. A color image forming apparatus according to claim 2, wherein said line width correcting means reduces toner amount around edge portions of line images so as to prevent toner from scattering around the edge portions.

7. A color image forming apparatus according to claim 3, wherein said line width correcting means reduces toner amount around edge portions of line images so as to prevent toner from scattering around the edge portions.

8. A color image forming apparatus according to claim 4, wherein said line width correcting means reduces toner amount around edge portions of line images so as to prevent toner from scattering around the edge portions.

9. A color image forming apparatus according to claim 5, wherein said line width correction means includes a plurality of correction patterns and reduces toner amount around edge portions based on selecting one of said plurality of correction patterns for the subsequent image forming operations.

10. A color image forming apparatus according to claim 6, wherein said line width correction means includes a plurality of correction patterns and reduces toner amount around edge portions based on selecting one of said plurality of correction patterns for the subsequent image forming operation.

11. A color image forming apparatus according to claim 9, wherein said one of said plurality of correction patterns is selected based on characteristics of a read image.

12. A color image forming apparatus according to claim 10, wherein said one of said plurality of correction patterns is selected based on characteristics of a read image.

13. A color image forming apparatus comprising:

correction excluding means for excluding at least one predetermined color data of an object pixel from a correction operation;

boundary detecting means for detecting a boundary of a background pixel and a non-background pixel;

object pixel detecting means for detecting a distance from the background pixel to the object pixel; and

correcting means for correcting the object pixel based on a result of the detected distance from the background pixel to the object pixel detected by said object pixel detecting means.

14. A color image forming apparatus according to claim 13, further comprising pixel data converting means for comparing a result corrected by said correcting means and data of the non-background pixel and replacing data of the object pixel with said data of the non-background based on a result of the comparison.

15. A color image forming apparatus according to claim 13, further comprising line width detecting means for detecting a width of a line image, and wherein the object pixel is not corrected if the object pixel is in a line image having a width smaller than a predetermined value.

16. A color image forming apparatus according to claim 14, further comprising line width detecting means for detecting a width of a line image, and wherein the object pixel is not corrected if the object pixel is in a line image having a width smaller than a predetermined value.

17. A color image forming apparatus according to claim 13, wherein a color image is formed by a side-by-side color image forming type of apparatus.

18. A color image forming apparatus according to claim 14, wherein a color image is formed by a side-by-side color image forming type of apparatus.

19. A color image forming apparatus according to claim 13, wherein a color image is formed by a color toner laying type of apparatus.

20. A color image forming apparatus according to claim 14, wherein a color image is formed by a color toner laying type of apparatus.