Ink-jet printer and control method for ink-jet printer

1. An ink-jet printer, comprising:

a first black record head configured to jet black ink;

a second black record head configured to jet black ink;

a color record head configured to jet ink in a specified color ink;

a black maintenance unit configured to maintain the first black record head;

a color maintenance unit configured to maintain the second black record head and the color record head; and

a controller configured to enable the black maintenance unit to maintain the first black record head when an image is recorded by the second black record head and the color record head, and the color maintenance unit to maintain the second black record head and the color record head when an image is recorded by the first black record head.

2. The ink-jet printer according to claim 1 , wherein

the first black record head, the second black record head and the color record head are a line head unit respectively having a width greater than the length of a conveyed recording medium in a direction orthogonal to the conveyance direction of the recording medium.

3. The ink-jet printer according to claim 1 , wherein

the black maintenance unit and the color maintenance unit have a plurality of types of maintenance functions respectively.

4. The ink-jet printer according to claim 1 , wherein

the color record head includes a cyan record head to jet cyan ink, a magenta record head to jet magenta ink, and a yellow record head to jet yellow ink.

5. The ink-jet printer according to claim 1 , further comprising a conveyor belt which conveys a recording medium.

6. The ink-jet printer according to claim 5 , further comprising a gadget which moves the first black record head away from the conveyor belt when the color printing is executed by the second black record head and color record head.

7. The ink-jet printer according to claim 5 , further comprising a gadget which moves the second black record head and color record head away from the conveyor belt when an image is recorded by the first black record head.

8. A Control method for an ink-jet printer, comprising:

determining execution of monochrome printing or color printing on a sheet;

recording an image on the sheet using a first black record head after determining to execute monochrome printing;

recording an image on the sheet using a second black record head and a color record head after determining to execute color printing; and

maintaining the first black record head using a black maintenance unit when the color printing is executed by the second black record head and color record head, and the second black record head and the color record head using a color maintenance unit when the monochrome printing is executed by the first black record head.

9. An ink-jet printer, comprising:

a first black record head configured to jet black ink;

a second black record head configured to jet black ink;

a color record head configured to jet ink in a specified color ink;

a black maintenance unit configured to maintain the first black record head, the black maintenance unit having a plurality of types of maintenance functions;

a color maintenance unit configured to maintain the second black record head and the color record head; and

a controller configured to enable the black maintenance unit to maintain the first black record head when an image is recorded by the second black record head and the color record head, and the color maintenance unit to maintain the second black record head and the color record head when an image is recorded by the first black record head execute the maintenance of the black maintenance unit and the maintenance of the color maintenance unit at different timings when the recording is executed by the first or second black record head.

10. The ink-jet printer according to claim 9 , wherein

the color maintenance unit has a plurality of types of maintenance functions.

11. The ink-jet printer according to claim 9 , wherein

the color record head includes a cyan record head to jet cyan ink, a magenta record head to jet magenta ink, and a yellow record head to jet yellow ink.

12. The ink-jet printer according to claim 9 , further comprising a conveyor belt which conveys a recording medium.

13. The ink-jet printer according to claim 12 , further comprising a gadget which moves the first black record head away from the conveyor belt when the color printing is executed by the second black record head and color record head.

14. The ink-jet printer according to claim 12 , further comprising a gadget which moves the second black record head and color record head away from the conveyor belt when an image is recorded by the first black record head.