Image forming apparatus

• US 20050062784A1
• Filed: 07/30/2004
• Published: 03/24/2005
• Est. Priority Date: 08/07/2003
• Status: Active Grant

• Current Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Inventors: Kawauchi, Kenichi, Matsuzaki, Yoshiki, Kazama, Toshiyuki, Kato, Takeshi, Goto, Osamu, Tagawa, Kozo, Ando, Ryo, Udaka, Tsutomu
• Granted Patent: US 7,216,948 B2
• Time in Patent Office: Days
• US Class Current: 347/19
• CPC Class Codes: B41J 2/04505 aiming at correcting alignment
• CPC Class Codes: B41J 2/04573 Timing; Delays
• CPC Class Codes: B41J 2/04586 controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type
• CPC Class Codes: B41J 2/155 for line printing

Abstract

An image forming apparatus has: a recording head having plural unit recording heads divided in a direction orthogonal to a moving direction of a recording medium; a detecting section detecting at least offset of an image recorded by a vicinity of an end portion, in the direction orthogonal to the moving direction of the recording medium, of the plural unit recording heads; and a correcting section correcting recording offset of the recording head on the basis of results of detection of the detecting section.

Claims

1. An image forming apparatus comprising:

a recording head having a plurality of unit recording heads divided in a direction orthogonal to a moving direction of a recording medium;

a detecting section detecting at least offset of an image recorded by a vicinity of an end portion, in the direction orthogonal to the moving direction of the recording medium, of the plurality of unit recording heads; and

a correcting section correcting recording offset of the recording head on the basis of results of detection of the detecting section.

2. The image forming apparatus of claim 1, wherein the correcting section corrects recording offset, in the direction orthogonal to the moving direction of the recording medium, of each of the plurality of unit recording heads.

3. The image forming apparatus of claim 2, wherein the correcting section corrects the recording offset in the direction orthogonal to the moving direction of the recording medium, by changing a recording region of each of the plurality of unit recording heads.

4. The image forming apparatus of claim 1, wherein the recording head includes unit recording heads recording images of plural colors.

5. The image forming apparatus of claim 1, wherein the correcting section corrects recording offset, in the moving direction of the recording medium, of each of the plurality of unit recording heads.

6. The image forming apparatus of claim 5, wherein the correcting section corrects the recording offset in the moving direction of the recording medium, by changing a recording timing of each of the plurality of unit recording heads.

7. The image forming apparatus of claim 1, wherein the correcting section changes a recording timing of each of the plurality of unit recording heads, so as to offset inclining of image recording positions caused by inclining of each of the plurality of unit recording heads.

8. The image forming apparatus of claim 7, wherein the correcting section divides a recording region of one unit recording head of the plurality of unit recording heads into plural regions, and changes the recording timings of the plural regions discretely.

9. The image forming apparatus of claim 8, wherein, when the correcting section divides the recording region of the one unit recording head into the plural regions, a number of divisions is determined in accordance with an inclination offset amount of the image recording position.

10. The image forming apparatus of claim 1, wherein, given that a number of divisions of the recording head in the direction orthogonal to the moving direction of the recording medium is N, (N−

1) of the detecting sections are provided.

11. The image forming apparatus of claim 1, wherein, given that a number of divisions of the recording head in the direction orthogonal to the moving direction of the recording medium is N, (N+1) of the detecting sections are provided.

12. The image forming apparatus of claim 1, wherein the recording head is structured by a plurality of units, with one unit being a predetermined number of the unit recording heads among the plurality of unit recording heads.

13. The image forming apparatus of claim 1, wherein each of the plurality of unit recording heads has a plurality of nozzles which discharge ink.

14. The image forming apparatus of claim 1, wherein the plurality of unit recording heads are disposed substantially along an entire width in the direction orthogonal to the moving direction of the recording medium, and are in staggered rows which are disposed so as to be offset in both the moving direction of the recording medium and the direction orthogonal to the moving direction of the recording medium.

15. The image forming apparatus of claim 14, wherein adjacent unit recording heads among the plurality of unit recording heads have regions which overlap in the direction orthogonal to the moving direction of the recording medium.

16. The image forming apparatus of claim 15, wherein the detecting section is provided at a position of detecting an image recorded by portions of the unit recording heads corresponding to the regions which overlap.

17. The image forming apparatus of claim 1, wherein the detecting section includes a CCD sensor.

18. The image forming apparatus of claim 1, wherein a predetermined test pattern is recorded on the recording medium, the predetermined test pattern is detected by the detecting section, and the correcting section corrects the recording offset of the recording head on the basis of the results of detection of the detecting section.

19. The image forming apparatus of claim 18, wherein the predetermined test pattern is recorded at predetermined intervals at positions corresponding to junctures of recording positions of adjacent recording heads among the plurality of unit recording heads.

20. The image forming apparatus of claim 1, wherein the detecting section is substantially shaped as a bar which extends in the direction orthogonal to the moving direction of the recording medium, and is longer than a width of the recording medium in the direction orthogonal to the moving direction of the recording medium.

21. An image forming apparatus comprising:

a recording head having a plurality of unit recording heads divided in a direction orthogonal to a moving direction of a recording medium;

a detecting section detecting at least offset of an image recorded by a vicinity of an end portion, in the direction orthogonal to the moving direction of the recording medium, of the plurality of unit recording heads; and

a correcting section correcting recording offset of the recording head on the basis of results of detection of the detecting section,

wherein the recording head has a plurality of blocks, with each block being structured by a predetermined number of the unit recording heads, which can record images of plural colors and which are lined-up along the moving direction of the recording medium, and

the plurality of blocks are lined-up in a staggered form along the direction orthogonal to the moving direction of the recording medium.

22. The image forming apparatus of claim 21, wherein the correcting section corrects recording offset, in the direction orthogonal to the moving direction of the recording medium, of each of the plurality of unit recording heads, and corrects recording offset, in the moving direction of the recording medium, of each of the plurality of unit recording heads.