Inkjet recording apparatus

1. An inkjet recording apparatus, comprising:

a conveying belt that has opposite front and rear surfaces and a plurality of through-holes extending through the conveying belt from the front surface to the rear surface thereof, the conveying belt conveying a recording medium in a conveying direction with the recording medium placed on the front surface thereof;

an inkjet head that has a nozzle surface provided with a plurality of nozzles and disposed opposite to the front surface of the conveying belt;

a plate-like conveying platen disposed opposite to rear surface of the conveying belt and provided with a plurality of air circulation parts, each of which includes a long groove opened toward the conveying belt and formed in a longitudinal direction following the conveying direction, and a hole that penetrates in a thickness direction from a part of a bottom surface of the long groove, the air circulation parts being arrayed in the conveying direction and a width direction perpendicular to the conveying direction; and

a negative pressure generating part that generates negative pressure to suction the recording medium through the air circulation parts of the conveying platen and the through-holes of the conveying belt and adsorb the recording medium onto the conveying belt,

wherein the conveying platen has an opposed region that faces the nozzle surface, a part of the long groove is provided in the opposed region, and the hole is provided only in a region other than the opposed region.

2. The inkjet recording apparatus according to claim 1 , wherein in two adjacent air circulation parts in the width direction, each of which is provided with the part of the long groove at the opposed region, the hole of one of the two adjacent air circulation parts is provided in a position on an upstream side away from the opposed region, and the hole of the other one of the two adjacent air circulation parts is provided in a position on a downstream side away from the opposed region.

3. The inkjet recording apparatus according to claim 2 , wherein each of the holes of the two adjacent air circulation parts is provided in a position adjacent to the opposed region.

4. The inkjet recording apparatus according to claim 2 , wherein a downstream side end part of the long groove of the one of the two adjacent air circulation parts is provided in the opposed region, or in a position adjacent to the opposed region on the downstream side away from the opposed region.

5. The inkjet recording apparatus according to claim 2 , wherein an upstream side end part of the long groove of the other one of the two adjacent air circulation parts is provided in the opposed region, or in a position adjacent to the opposed region on the upstream side away from the opposed region.

6. The inkjet recording apparatus according to claim 2 , wherein in the two adjacent air circulation parts, the long groove of the one of the two adjacent air circulation parts and the long groove of the other one of the two adjacent air circulation parts are provided in positions where end parts of the long grooves do not face each other in the width direction.

7. The inkjet recording apparatus according to claim 1 , wherein the hole is located at a position other than a central position of the long groove in the longitudinal direction such that the hole is positioned in the region other than the opposed region.

8. The inkjet recording apparatus according to claim 1 , wherein the air circulation parts include a first long groove and a second long groove having a length in the longitudinal direction different from a length of the first long groove in the longitudinal direction.

9. The inkjet recording apparatus according to claim 1 , wherein the air circulation parts are disposed on an area of the conveying platen to communicate with the through-holes of the conveying belt.

10. An inkjet recording apparatus comprising:

a conveying belt that has opposite front and rear surfaces and a plurality of through-holes extending through the conveying belt from the front surface to the rear surface thereof, the conveying belt conveying a recording medium in a conveying direction with the recording medium placed on the front surface thereof;

an inkjet head that has a nozzle surface provided with a plurality of nozzles and disposed opposite to the front surface of the conveying belt;

a plate-like conveying platen disposed opposite to the rear surface of the conveying belt and provided with a plurality of air circulation parts, each of which includes a long groove opened toward the conveying belt and formed in a longitudinal direction following the conveying direction, and a hole that penetrates in a thickness direction from a part of a bottom surface of the long groove, the air circulation parts being arrayed in the conveying direction and in width direction perpendicular to the conveying direction; and

a negative pressure generating part that generates negative pressure to suction the recording medium through the air circulation parts of the conveying platen and the through-holes of the conveying belt and adsorb the recording medium onto the conveying belt, wherein

the conveying platen has an opposed region that faces the nozzle surface, a part of the long groove is provided in the opposed region, the hole is located at a position other than a central position of the long groove in the longitudinal direction such that the hole is positioned in a region other than the opposed region.

11. The inkjet recording apparatus according to claim 10 , wherein the air circulation parts include a first long groove, and a second long groove having a length in the longitudinal direction different from a length of the first long groove in the longitudinal direction.

12. The inkjet recording apparatus according to claim 10 , wherein the air circulation parts are disposed on an area of the conveying platen and to communicate with the through holes of the conveying belt.

13. An inkjet recording apparatus, comprising:

a conveying belt that has opposite front and rear surfaces and a plurality of through-holes extending through the conveying belt from the front surface to the rear surface thereof, the conveying belt conveying a recording medium in a conveying direction with the recording medium placed on the front surface thereof;

an inkjet head that has a nozzle surface provided with a plurality of nozzles and disposed opposite to the front surface of the conveying belt;

a plate-like conveying platen disposed opposite to the rear surface of the conveying belt and provided with a plurality of air circulation parts, each of which includes a long groove opened toward the conveying belt and formed in a longitudinal direction following the conveying direction, and a hole that penetrates in a thickness direction from a part of a bottom surface of the long groove, the air circulation parts being arrayed in the conveying direction and a width direction perpendicular to the conveying direction; and

a negative pressure generating part that generates negative pressure to suction the recording medium through the air circulation parts of the conveying platen and the through-holes of the conveying belt and adsorb the recording medium on to the conveying belt, wherein

the conveying platen has an opposed region that faces the nozzle surface, a part of the long groove is provided in the opposed region, and the hole is provided in a region other than the opposed region, and

the air circulation parts include a first long groove, and a second long groove having a length in the longitudinal direction different from a length of the first long groove in the longitudinal direction.

14. The inkjet recording apparatus according to claim 13 , wherein the air circulation parts are disposed on an area of the conveying platen to communicate with the through-holes of the conveying belt.