INK JET PRINTING APPARATUS AND PRINTING METHOD

• US 20070273899A1
• Filed: 05/18/2007
• Published: 11/29/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kameda, Hirokazu, Yano, Fumiko, Kanazawa, Manabu, Ide, Daisaku, Yasutani, Jun, Nishikori, Hitoshi, Yazawa, Takeshi
• Granted Patent: US 7,903,280 B2
• Time in Patent Office: Days
• US Class Current: 358/1.800
• CPC Class Codes: B41J 2/2132 Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding methods for local corrections by dot omission, image edge enhancement, or multi-pass mask selection G06K15/102; colour conversion H04N1/40
• CPC Class Codes: G06K 15/107 Mask selection

Abstract

By suppressing deviation of dot-formation positions stemming from insufficient accuracy in conveying a printing medium due to eccentricity of a conveying roller, a printed image in which unevenness is less visible is obtained. An accumulated amount of conveyance errors is reduced by narrowing a nozzle-use range and by reducing a conveyance amount over an entire printing region according to the number of colors to be used and desired printing quality in printing an image. Moreover, the nozzles used when the nozzle-use range is narrowed are not fixed, and are switched to be used as appropriate. This prevents only certain nozzles from being used concentratedly, and allows all of the nozzles to maintain substantially the same ejection performance.

Claims

1. An ink jet printing apparatus for printing an image on a printing medium by performing a print scan that makes a print while causing a printing head, which includes arrays of printing elements for ejecting inks of different colors, to scan on a printing medium, and by conveying the printing medium in a direction intersecting with a direction of the print scan, the apparatus comprising:

print controller capable of executing a first printing mode for performing the print scan that makes a print by using a part of the array of printing elements arranged continuously, over an entire print region on the printing medium; and

switching unit which switches, in the array of printing elements, the continuously-arranged printing elements used in the first printing mode.

2. An ink jet printing apparatus as claimed in claim 1, wherein the print controller executes the first printing mode when monochrome-image printing is selected.

3. An ink jet printing apparatus as claimed in claim 2, wherein the monochrome image is an achromatic monochrome image.

4. An ink jet printing apparatus as claimed in claim 3, wherein

the printing head has the array of printing elements for ejecting an achromatic ink, and the array of printing elements for ejecting a chromatic ink, and

the monochrome image is printed by using the achromatic ink and the chromatic ink in the printing mode for the monochrome image, while dominantly using the achromatic ink in all density regions.

5. An ink jet printing apparatus as claimed in claim 2, wherein the print controller can execute a second printing mode used for performing the print scan, which makes a print by using the entire array of printing elements, on at least a part of the printing region of the printing medium, in a case where the monochrome-image printing is not selected.

6. An ink jet printing apparatus as claimed in claim 2, wherein the print controller (A) executes the first printing mode in a case where the monochrome-image printing is selected, and where a first type of printing medium is designated as a type of the printing medium, and (B) executes the second printing mode used for performing the print scan, which makes a print by using the entire array of printing elements, on at least a part of the printing region of the printing medium in a case where monochrome-image printing is selected, and where a second type of printing medium is designated as the type of the printing medium.

7. An ink jet printing apparatus as claimed in claim 5, wherein the second printing mode executes the print scan which makes a print by using all of the array of printing elements, on a central portion of the printing medium, and executes the print scan, which makes a print by using a smaller number of printing elements than that of the entire array of printing elements, on at least one of a front portion and a rear portion of the printing medium.

8. An ink jet printing apparatus as claimed in claim 1, wherein the print controller determines whether the first printing mode is executed, according to at least one of conditions including a type of printing medium and quality of an image to be printed.

9. An ink jet printing apparatus as claimed in claim 1, wherein the switching unit performs the switching at a timing when a page of a printing medium is changed to another one.

10. An ink jet printing apparatus as claimed in claim 9, further comprising managing unit which accumulatively manages the number of printed printing media,

wherein, according to an accumulated value obtained by the managing unit, the switching unit performs the switching.

11. An ink jet printing apparatus as claimed in claim 9, further comprising managing unit which manages an accumulated value of the number of ejection operations executed by the printing head,

wherein, after the accumulated value of the number of ejection operations exceeds a predetermined threshold, the switching unit performs the switching at a timing when a page of a printing medium is changed to another one.

12. An ink jet printing apparatus as claimed in claim 1, wherein the switching unit performs the switching within one page.

13. A method of ink jet printing an image on a printing medium by performing a print scan that makes a print while causing a printing head, which includes arrays of printing elements for ejecting inks of different colors, to scan on a printing medium, and by conveying the printing medium in a direction intersecting with a direction of the print scan, the method comprising the steps of:

executing the print scan, which makes a print by using a part of the array of printing elements arranged continuously, over an entire printing region of the printing medium; and

switching the continuously-arranged printing elements used when the print scan is executed, in the array of printing elements.