Liquid ejection apparatus, liquid ejection system, and liquid ejection method

1. A liquid ejection apparatus, comprising:

a plurality of liquid ejection head units that are configured to eject liquid onto a first side of a conveyed object at different positions along a conveying path for conveying the conveyed object;

a first support member that supports the conveyed object and is provided upstream of a landing position of the liquid ejected onto the first side of the conveyed object by a corresponding liquid ejection head unit of the plurality of liquid ejection head units;

a second support member that supports the conveyed object and is provided downstream of the landing position of the corresponding liquid ejection head unit;

at least one detection unit that is

installed between the first support member and the second support member,

configured to detect a position of the conveyed object upstream of the landing position with respect to an orthogonal direction that is orthogonal to a conveying direction of the conveyed object; and

a movement control unit that is configured to move each liquid ejection head unit of the plurality of liquid ejection head units based on at least two detection results output by the detection unit, wherein

each liquid ejection head unit of the plurality of liquid ejection head units faces the first side of the conveyed object, and

the detection unit faces a second side of the conveyed object, the second surface being an opposite side of the conveyed object from the first side.

2. The liquid ejection apparatus according to claim 1 , wherein

the first support member is arranged downstream of a landing position of an upstream liquid ejection head unit located upstream of the corresponding liquid ejection head unit; and

the second support member is arranged upstream of a landing position of a downstream liquid ejection head unit located downstream of the corresponding liquid ejection head unit.

3. The liquid ejection apparatus according to claim 1 , wherein the first support member and the second support member are provided with respect to the each liquid ejection head unit of the plurality of liquid ejection head units.

4. The liquid ejection apparatus according to claim 1 , wherein the detection unit is positioned between the first support member and the landing position of the corresponding liquid ejection head unit.

5. The liquid ejection apparatus according to claim 1 , wherein the movement control unit moves the each liquid ejection bead unit in the orthogonal direction that is orthogonal to the conveying direction of the conveyed object.

6. The liquid ejection apparatus according to claim 1 , wherein the detection unit uses an optical sensor.

7. The liquid ejection apparatus according to claim 6 , wherein the detection unit is configured to obtain the detection results based on a pattern included in the conveyed object.

8. The liquid ejection apparatus according to claim 7 , wherein

the pattern is generated by interference of light irradiated on a roughness formed on the conveyed object; and

the detection unit is configured to obtain the detection results based on an image capturing the pattern of the conveyed object.

9. The liquid ejection apparatus according to claim 1 , further comprising:

a measuring unit configured to measure an amount of movement in the conveying direction of the conveyed object;

wherein the liquid is ejected based on the amount of movement measured by the measuring unit and the at least two detection results.

10. The liquid ejection apparatus according to claim 1 , wherein the conveyed object is a long continuous sheet extending in the conveying direction.

11. The liquid ejection apparatus according to claim 1 , further comprising:

a calculating unit that is provided with respect to the each liquid ejection head unit of the plurality of liquid ejection head units and is configured to calculate an amount of positional variation of the conveyed object by comparing the at least two detection results including a first detection result and a second detection result;

wherein the movement control unit moves a liquid ejection head unit of the plurality of liquid ejection head units based on the amount of positional variation calculated with respect to the liquid ejection head unit;

wherein the first detection result is detected by the detection unit that is installed upstream of the liquid ejection head unit to be moved by the movement control unit; and

wherein the second detection result is detected by the detection unit that is installed closest to the liquid ejection head unit to be moved by the movement control unit.

12. The liquid ejection apparatus according to claim 11 , wherein the first detection result is detected by the detection unit that is installed immediately upstream of the liquid ejection head unit to be moved by the movement control unit.

13. The liquid ejection apparatus according to claim 1 , wherein the detection unit and the second detection are installed at positions that are equidistant from each other.

14. A liquid ejection system including at least one liquid ejection apparatus, the liquid ejection system comprising:

a plurality of liquid ejection head units that are configured to eject liquid onto a first side of a conveyed object at different positions along a conveying path for conveying the conveyed object;

a first support member that supports the conveyed object and is provided upstream of a landing position of the liquid ejected onto the first side of the conveyed of by a corresponding liquid ejection head unit of the plurality of liquid ejection head units;

a second support member that supports the conveyed object and is provided downstream of the landing position of the corresponding liquid ejection head unit;

at least one detection unit that is

installed between the first support member and the second support member,

configured to detect a position of the conveyed object upstream of the landing position with respect to an orthogonal direction that is orthogonal to a conveying direction of the conveyed object; and

a movement control unit that is configured to move each liquid ejection head unit of the plurality of liquid ejection bead units based on at least two detection results output by the detection unit, wherein

each liquid ejection head unit of the plurality of liquid ejection head units faces the first side of the conveyed object, and

the detection unit faces a second side of the conveyed object, the second side being an opposite side of the conveyed object from the first side.

15. A liquid ejection method that is implemented by a liquid ejection apparatus including

a plurality of liquid ejection head units that are configured to eject liquid onto a first side of a conveyed object at different positions along a conveying path for conveying the conveyed object;

a first support member that supports the conveyed object and is provided upstream of a landing position of the liquid ejected onto the first side of the conveyed object by a corresponding liquid ejection head unit of the plurality of liquid ejection head units;

a second support member that supports the conveyed object and is provided downstream of the landing position of the corresponding liquid ejection head unit; and

at least one detection unit that is

installed between the first support member and the second support member,

configured to detect a position of the conveyed object upstream of the landing position with respect to an orthogonal direction that is orthogonal to a conveying direction of the conveyed object, wherein

each liquid ejection head unit of the plurality of liquid ejection head units faces the first side of the conveyed object, and

the detection unit faces a second side of the conveyed object, the second side being an opposite side of the conveyed object from the first side;

the liquid ejection method comprising:

moving each liquid ejection head unit of the plurality of liquid ejection head units based on at least two detection results output by the detection unit.