Inkjet printer

Abstract

To suppress generation of twisting in a shaft holding a grit roller.SOLUTION: A printer 10 is equipped with a platen 16 that has a placing surface 16A on which a recording medium 5 is placed, a carriage 30, an ink head 34 that discharges ink to the recording medium 5 carried in a sub-scanning direction X, a rotatable first shaft 61 that has an axis 61C located under the placing surface 16A and extends in a main-scanning direction Y, a first grit roller 62 that is provided on the first shaft 61 and carries the recording medium 5 in the sub-scanning direction X, a first drive mechanism 63 that rotates the first shaft 61, a second shaft 65 that can rotate independently from the first shaft 61, has an axis 65C located under the placing surface 16A, and extends in the main-scanning direction Y, a second grit roller 66 that is provided on the second shaft 65 and carries the recording medium 5 in the sub-scanning direction X, and a second drive mechanism 67 that rotates the second shaft 65.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an inkjet printer.

Background Art

[0002] Conventionally, an inkjet printer that prints an image on a recording medium by an inkjet method is known. This type of inkjet printer includes, for example, a platen on which a recording medium is placed, and an ink head that is movably provided in the main scanning direction and discharges ink onto the recording medium placed on the platen. Further, the recording medium placed on the platen is conveyed in a sub-scanning direction orthogonal to the main scanning direction by a grit roller provided on the platen. For example, Patent Document 1 discloses a printer including a plurality of grit rollers embedded in a platen such that the upper portions of the grit rollers are exposed to the outside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a plurality of grit rollers as shown in Patent Document 1 are conventionally provided so as to be arranged in the main scanning direction on one shaft, and the whole rotates integrally. Usually, a drive mechanism is provided at one end of the shaft, and the shaft is rotated by the drive mechanism. Here, for example, in the case of a relatively large printer, since the length of the shaft in the main scanning direction becomes long, there is a risk of torsion occurring on the other end side of the shaft when the shaft is rotated. If torsion occurs in the shaft, there is a risk that the recording medium cannot be accurately conveyed in the sub-scanning direction.

[0005] The present invention has been made in view of such a point, and an object thereof is to provide an inkjet printer capable of suppressing the occurrence of torsion in a shaft that holds a grit roller.

Means for Solving the Problems

[0006] The inkjet printer according to the present invention includes a platen having a placement surface on which a recording medium is placed, a carriage disposed above the platen and movable in a main scanning direction, an ink head mounted on the carriage and discharging ink onto the recording medium conveyed in a sub-scanning direction orthogonal to the main scanning direction, a rotatable first shaft whose axis is located below the placement surface of the platen and extending in the main scanning direction, a first grit roller provided on the first shaft and at least a part of which protrudes above the placement surface of the platen to convey the recording medium in the sub-scanning direction, a first drive mechanism for rotating the first shaft, a shaft rotatable independently of the first shaft, a rotatable second shaft whose axis is located below the placement surface of the platen and extending in the main scanning direction, a second grit roller provided on the second shaft and at least a part of which protrudes above the placement surface of the platen to convey the recording medium in the sub-scanning direction, and a second drive mechanism for rotating the second shaft.

[0007] According to the inkjet printer of the present invention, the first grit roller and the second grit roller for conveying the recording medium in the sub-scanning direction are respectively provided on the first shaft and the second shaft. And the second shaft is provided to be rotatable independently of the first shaft. That is, the first shaft and the second shaft are separate bodies. For this reason, compared with the case where the first grit roller and the second grit roller are held by one shaft, the lengths of the first shaft and the second shaft in the main scanning direction can be shortened respectively. Thereby, the occurrence of torsion in each of the first shaft and the second shaft when rotating them is suppressed. As a result, the recording medium can be conveyed more accurately in the sub-scanning direction.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide an inkjet printer that can suppress the occurrence of torsion in a shaft that holds a grit roller.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an inkjet printer (hereinafter simply referred to as "printer") according to an embodiment of the present invention will be described with reference to the drawings. Note that the embodiments described here are not intended to particularly limit the present invention. In addition, members and parts having the same function are denoted by the same reference numerals, and redundant descriptions are omitted or simplified as appropriate.

[0011] FIG. 1 is a perspective view showing a printer 10 according to the present embodiment. The printer 10 performs printing on a recording medium 5 (see FIG. 2). The recording medium 5 is formed in a long shape, for example, and is used by being wound in a roll shape. Note that the recording medium 5 may be in the form of a sheet obtained by cutting a roll-shaped one to a predetermined length. The recording medium 5 is, for example, recording paper. However, the recording medium 5 is not limited to recording paper. For example, the recording medium 5 includes a sheet formed of a resin material such as polyvinyl chloride (PVC) or polyester, a sealing material composed of a base paper and a release paper laminated on the base paper and coated with an adhesive, and the like.

[0012] In the following description, "left", "right", "up", and "down" mean left, right, up, and down as viewed from an operator standing in front of the printer 10, respectively. Also, when the operator is facing the front of the printer 10, the direction from the rear of the printer 10 toward the operator is defined as the front, and the direction from the operator toward the rear of the printer 10 is defined as the rear. In the drawings, the reference signs F, Rr, L, R, U, and D represent the front, rear, left, right, up, and down, respectively. A carriage 30 described later is provided so as to be movable leftward and rightward. When the rear side of the printer 10 is the upstream side and the front side of the printer 10 is the downstream side, the recording medium 5 is conveyed from the upstream side toward the downstream side. In the present embodiment, the moving direction of the carriage 30 is referred to as the main scanning direction Y, and the conveying direction of the recording medium 5 is referred to as the sub-scanning direction X. Here, the main scanning direction Y corresponds to the left-right direction, and the sub-scanning direction X corresponds to the front-rear direction. The main scanning direction Y and the sub-scanning direction X are orthogonal to each other. However, the main scanning direction Y and the sub-scanning direction X are not particularly limited and can be appropriately set according to the form of the printer 10 and the like.

[0013] As shown in FIG. 1, the printer 10 includes a base member 40, a platen 16 (see also FIG. 2) on which a recording medium 5 is placed, a guide member 19 that guides the movement of the recording medium 5 conveyed from the platen 16, a case 50 attached to the base member 40, a right leg portion 11R, a left leg portion 11L, an ink head unit 35, and a control device 80. The base member 40 extends in the main scanning direction Y. The right leg portion 11R and the left leg portion 11L are attached to the lower part of the base member 40. The right leg portion 11R and the left leg portion 11L support the base member 40.

[0014] As shown in FIG. 2, the platen 16 extends in the main scanning direction Y. The platen 16 has a placement surface 16A on which the recording medium 5 is placed. The placement surface 16A is formed in a flat shape. Printing on the recording medium 5 is performed on the platen 16. The platen 16 is supported by the base member 40 (see FIG. 1). The guide member 19 is disposed in front of the platen 16. The guide member 19 is supported by the base member 40. The upper surface 19A of the guide member 19 is inclined obliquely downward from the rear to the front. The guide member 19 is formed, for example, in an arc-shaped cross section. The guide member 19 guides the movement of the recording medium 5 from the platen 16.

[0015] As shown in FIG. 1, the printer 10 includes a central wall 17 that extends in the main scanning direction Y and the vertical direction. The central wall 17 is supported by the base member 40. The central wall 17 is disposed above the platen 16. A gap through which the recording medium 5 can pass is formed between the central wall 17 and the platen 16. The central wall 17 is housed in the case 50.

[0016] As shown in FIG. 1, the printer 10 includes a guide rail 18. The guide rail 18 extends in the main scanning direction Y. The guide rail 18 is provided on the central wall 17. The guide rail 18 is disposed above the platen 16.

[0017] As shown in FIG. 1, the ink head unit 35 is provided on the base member 40. The ink head unit 35 is disposed inside the case 50. The ink head unit 35 is disposed above the platen 16. The ink head unit 35 includes a carriage 30 and an ink head 34. The carriage 30 is disposed above the platen 16. The carriage 30 engages with the guide rail 18. The carriage 30 is configured to be movable in the main scanning direction Y along the guide rail 18. The ink head 34 has nozzles (not shown) for discharging ink onto the recording medium 5 placed on the platen 16. The ink head 34 is configured to be able to print a predetermined image and crop marks on the recording medium 5. The ink head 34 prints, for example, an image 7 and crop marks 8A to 8D on the surface of the recording medium 5 as shown in FIG. 5. The crop marks 8A to 8D are respectively provided outside the four corners of the rectangular area 9 including the image 7. The crop marks 8A to 8D are formed, for example, by black circles. The crop marks 8A to 8D are respectively provided at the upper left diagonal, upper right diagonal, lower left diagonal, and lower right diagonal of FIG. 5 of the rectangular area 9. The ink head 34 is mounted on the carriage 30. The ink head 34 is configured to be movable in the main scanning direction Y as the carriage 30 moves.

[0018] As shown in FIG. 1, the printer 10 includes a carriage movement mechanism 20. The carriage movement mechanism 20 is a mechanism that relatively moves the carriage 30 of the ink head unit 35 in the main scanning direction Y with respect to the recording medium 5 placed on the platen 16. The carriage movement mechanism 20 moves the carriage 30 in the main scanning direction Y. Note that the configuration of the carriage movement mechanism 20 is not particularly limited. The carriage movement mechanism 20 includes a first pulley 21, a second pulley 22, an endless belt 23, and a carriage motor 24 (see also FIG. 4). The first pulley 21 is provided on the left end side of the guide rail 18. The second pulley 22 is provided on the right end side of the guide rail 18. The belt 23 is wound around the first pulley 21 and the second pulley 22. The belt 23 is fixed to the upper part of the back surface of the carriage 30. The carriage motor 24 is connected to the second pulley 22. However, the carriage motor 24 may be connected to the first pulley 21. Here, when the carriage motor 24 is driven and the second pulley 22 rotates, the belt 23 travels between the first pulley 21 and the second pulley 22. Thereby, the carriage 30 moves in the main scanning direction Y.

[0019] As shown in FIG. 1, the printer 10 includes a medium movement mechanism 60. The medium movement mechanism 60 relatively moves the recording medium 5 placed on the platen 16 in the sub-scanning direction X with respect to the ink head unit 35. The medium movement mechanism 60 moves the recording medium 5 placed on the platen 16 in the sub-scanning direction X. Further, as will be described later, the medium movement mechanism 60 is configured to be able to correct the inclination of the recording medium 5 placed on the platen 16. As shown in FIG. 3, the medium movement mechanism 60 includes a first shaft 61, a first grit roller 62 held by the first shaft 61, a first drive mechanism 63 that rotates the first shaft, a second shaft 65, a second grit roller 66 held by the second shaft, a second drive mechanism 67 that rotates the second shaft 65, a plurality of first pinch roller units 71, a plurality of second pinch roller units 75, and a holding shaft 78.

[0020] As shown in FIG. 3, the first shaft 61 extends in the main scanning direction Y. The axis 61C of the first shaft 61 is located below the placement surface 16A of the platen 16. The first shaft 61 is rotatably provided on the platen 16. The first grit roller 62 is provided on the first shaft 61. The first grit roller 62 is held by the first shaft 61. The first grit roller 62 is embedded in the platen 16 such that the upper portion of the first grit roller 62 is exposed to the outside. That is, the upper portion of the first grit roller 62 protrudes above the placement surface 16A of the platen 16. The first grit rollers 62 are arranged in parallel in the main scanning direction Y. The first grit roller 62 conveys the recording medium 5 in the sub-scanning direction X. The first drive mechanism 63 rotates the first shaft 61. The first drive mechanism 63 is disposed to the right of the platen 16. The first drive mechanism 63 is provided on the base member 40. The first drive mechanism 63 includes a first drive motor 63A (see also FIG. 4), a first drive gear 63B provided on the first drive motor 63A, and a first driven gear 63C provided at the right end portion of the first shaft 61 and meshing with the first drive gear 63B. The first drive motor 63A is controlled by the control device 80. When the first drive motor 63A drives and the first shaft 61 rotates, the recording medium 5 is conveyed in the sub-scanning direction X.

[0021] As shown in FIG. 3, the second shaft 65 extends in the main scanning direction Y. The axis 65C of the second shaft 65 is positioned below the placement surface 16A of the platen 16. The second shaft 65 is provided to the left of the first shaft 61. The second shaft 65 is rotatably provided on the platen 16 independently of the first shaft 61. The second shaft 65 and the first shaft 61 are configured to be rotatable independently of each other. The second grit roller 66 is provided on the second shaft 65. The second grit roller 66 is held by the second shaft 65. The second grit roller 66 is embedded in the platen 16 such that the upper portion of the second grit roller 66 is exposed to the outside. That is, the upper portion of the second grit roller 66 protrudes above the placement surface 16A of the platen 16. The second grit rollers 66 are arranged in parallel in the main scanning direction Y. The second grit roller 66 conveys the recording medium 5 in the sub-scanning direction X. The second drive mechanism 67 rotates the second shaft 65. The second drive mechanism 67 is arranged to the left of the platen 16. The second drive mechanism 67 is provided on the base member 40. The second drive mechanism 67 includes a second drive motor 67A (see also FIG. 4), a second drive gear 67B provided on the second drive motor 67A, and a second driven gear 67C provided at the left end portion of the second shaft 65 and meshing with the second drive gear 67B. The second drive motor 67A is controlled by the control device 80. When the second drive motor 67A drives and the second shaft 65 rotates, the recording medium 5 is conveyed in the sub-scanning direction X.

[0022] As shown in FIG. 3, the first pinch roller unit 71 and the second pinch roller unit 75 are disposed above the platen 16. The first pinch roller unit 71 and the second pinch roller unit 75 are disposed below the guide rail 18. The first pinch roller unit 71 is disposed to the right of the second pinch roller unit 75. The first pinch roller unit 71 includes a first pinch roller 72 disposed above the first grit roller 62, and a first holding member 73 that rotatably holds the first pinch roller 72. The first pinch roller 72 is disposed at a position facing the first grit roller 62. The first pinch roller 72 presses the recording medium 5 placed on the platen 16 from above. The first pinch roller 72 sandwiches the recording medium 5 between itself and the first grit roller 62. The second pinch roller unit 75 includes a second pinch roller 76 disposed above the second grit roller 66, and a second holding member 77 that rotatably holds the second pinch roller 76. The second pinch roller 76 is disposed at a position facing the second grit roller 66. The second pinch roller 76 presses the recording medium 5 placed on the platen 16 from above. The second pinch roller 76 sandwiches the recording medium 5 between itself and the second grit roller 66. Note that in FIG. 2, the illustration of the first pinch roller unit 71 and the second pinch roller unit 75 is omitted.

[0023] As shown in FIG. 1, the holding shaft 78 extends in the main scanning direction Y. The holding shaft 78 holds the first pinch roller unit 71 and the second pinch roller unit 75. More specifically, the holding shaft 78 holds the first holding member 73 (see FIG. 3) of the first pinch roller unit 71 and the second holding member 77 (see FIG. 3) of the second pinch roller unit 75. By rotating the holding shaft 78 about its axis, the first pinch roller 72 and the second pinch roller 76 can be brought closer to the first grit roller 62 and the second grit roller 66, respectively, or separated from the first grit roller 62 and the second grit roller 66, respectively. The holding shaft 78 is disposed above the platen 16. The holding shaft 78 is rotatably supported by the base member 40.

[0024] As shown in FIG. 1, the printer 10 includes a detection device 55. The detection device 55 is configured to be able to detect crop marks (for example, crop marks 8A to 8D in FIG. 5) printed on the recording medium 5. Further, the detection device 55 is configured to be able to detect the position of the recording medium 5 in the main scanning direction Y with respect to the platen 16. The detection device 55 detects the position of the recording medium 5 in the main scanning direction Y with respect to the platen 16, for example, by detecting the right end portion 5R (see FIG. 7) and the left end portion 5L (see FIG. 7) of the recording medium 5. The detection device 55 is mounted on the carriage 30. The detection device 55 faces the platen 16. The detection device 55 is configured to be movable in the main scanning direction Y as the carriage 30 moves. Note that the two-dot chain line DL in FIG. 7 indicates the movement locus of the detection device 55. The detection device 55 is, for example, an optical sensor. However, the detection device 55 is not particularly limited to an optical sensor, and other sensors may be used.

[0025] As shown in FIG. 4, the overall operation of the printer 10 is controlled by a control device 80. The configuration of the control device 80 is not particularly limited. The control device 80 is, for example, a microcomputer. The hardware configuration of the microcomputer is not particularly limited, but for example, it includes an interface (I / F) for receiving print data and the like from an external device such as a host computer, a central processing unit (CPU) that executes instructions of a control program, a ROM that stores the program executed by the CPU, a RAM used as a working area for developing the program, and a storage device such as a memory for storing programs and various data. As shown in FIG. 1, the control device 80 is provided inside the case 50.

[0026] As shown in FIG. 4, the control device 80 is communicably connected to the carriage motor 24, the ink head 34, the detection device 55, the first drive motor 63A, and the second drive motor 67A, and controls them. When the control device 80 conveys the recording medium 5 in the sub-scanning direction X (except when correcting the inclination of the recording medium 5 described later), the first drive motor 63A and the second drive motor 67A are synchronized to convey the recording medium 5 straight in the sub-scanning direction X.

[0027] As shown in FIG. 5, when the recording medium 5 printed with the image 7 and the crop marks 8A to 8D is placed on the platen 16 (see FIG. 2) again for additional printing, the recording medium 5 may be placed inclined with respect to the platen 16. Further, as shown in FIG. 7, even when the recording medium 5 is placed straight with respect to the platen 16, the recording medium 5 may skew during conveyance in the sub-scanning direction X of the recording medium 5 during subsequent printing. According to the printer 10 of the present embodiment, the inclination of the recording medium 5 with respect to the platen 16 can be corrected as described later.

[0028] As shown in FIG. 4, the control device 80 includes a first detection unit 82, a first calculation unit 83, a first drive control unit 84, a determination unit 85, a second detection unit 86, a second calculation unit 87, and a second drive control unit 88. The functions of each part of the control device 80 are realized by a program. This program is read from a recording medium such as a CD or a DVD, for example. Note that this program may be downloaded through the Internet. Further, the functions of each part of the control device 80 may be realized by a processor and / or a circuit, etc. The specific functions of these parts will be described later.

[0029] The first detection unit 82 detects the first inclination amount of the recording medium 5 based on the position information of the crop marks 8A to 8D detected by the detection device 55. The first detection unit 82 moves the detection device 55 in the main scanning direction Y by controlling the carriage motor 24, and conveys the recording medium 5 in the sub-scanning direction X by controlling the first drive motor 63A and the second drive motor 67A. As a result, the detection device 55 can detect the crop marks 8A to 8D. The first inclination amount of the recording medium 5 is, for example, the rightward inclination θ1 (see FIG. 5) or the leftward inclination θ1 of the recording medium 5 with respect to the state where the recording medium 5 is placed straight (the right and left edges of the recording medium 5 are placed parallel to the sub-scanning direction X; see FIG. 6). The first inclination amount is the inclination of the recording medium 5 that can occur when the recording medium 5 is placed on the platen 16. Note that the first detection unit 82 can detect the first inclination amount based on the position information of three or more of the four crop marks 8A to 8D detected by the detection device 55.

[0030] The first calculation unit 83 calculates the rotation direction and rotation speed of the first shaft 61 and the rotation direction and rotation speed of the second shaft 65, which are the first correction conditions for setting the first inclination amount detected by the first detection unit 82 to zero. Here, the rotation speed is, for example, the number of rotations per unit time, that is, the rotation speed.

[0031] The first drive control unit 84 controls the first drive mechanism 63 and the second drive mechanism 67 based on the first correction conditions calculated by the first calculation unit 83. More specifically, the first drive control unit 84 controls the first drive motor 63A and the second drive motor 67A. For example, as shown in FIG. 5, when the recording medium 5 is inclined to the right, in order to make θ1 zero, the first shaft 61 (see FIG. 3) is stopped, and the second shaft 65 (see FIG. 3) is rotated in the direction in which the recording medium 5 is conveyed from the upstream side to the downstream side in the sub-scanning direction X. As a result, the recording medium 5 rotates in the direction of arrow R1 in FIG. 5 with the first grit roller 62 as a pivot point, and the recording medium 5 is placed straight as shown in FIG. 6.

[0032] The determination unit 85 determines whether or not the corrected first inclination amount is 0. Here, the corrected first inclination amount is detected by the first detection unit 82 based on the position information of the crop marks 8A to 8D that has been detected again by the detection device 55 after the first drive mechanism 63 and the second drive mechanism 67 are controlled based on the first correction condition. When the determination unit 85 determines that the corrected first inclination amount is 0, for example, the user is notified to that effect via a display device or an audio device. Note that when the determination unit 85 determines that the corrected first inclination amount is not 0, the user may be notified that the corrected first inclination amount is not 0, or the first calculation unit 83 and the first drive control unit 84 may perform control to correct the inclination of the recording medium 5 again.

[0033] The second detection unit 86 detects a second inclination amount of the recording medium 5 that occurs when the recording medium 5 is conveyed in the sub-scanning direction X based on the position of the recording medium 5 in the main scanning direction Y detected by the detection device 55. Since the carriage 30 moves in the main scanning direction Y during printing, the detection device 55 can always detect the right end portion 5R (see FIG. 7) and the left end portion 5L (see FIG. 7) of the recording medium 5. The second inclination amount of the recording medium 5 is represented by, for example, the rightward inclination θ2 or the leftward inclination θ2 (see FIG. 7) of the recording medium 5 with respect to the state in which the recording medium 5 is placed straight (see FIG. 6). The second inclination amount is an inclination of the recording medium 5 that can occur when the recording medium 5 is conveyed in the sub-scanning direction X.

[0034] The second calculation unit 87 calculates the rotation direction and the rotation speed of the first shaft 61 and the rotation direction and the rotation speed of the second shaft 65, which are second correction conditions for making the second inclination amount detected by the second detection unit 86 zero.

[0035] The second drive control unit 88 controls the first drive mechanism 63 and the second drive mechanism 67 based on the second correction condition calculated by the second calculation unit 87. More specifically, the second drive control unit 88 controls the first drive motor 63A and the second drive motor 67A. For example, as shown in FIG. 7, when the recording medium 5 is inclined to the left during printing, the second shaft 65 (see FIG. 3) is stopped to make θ2 zero, and the first shaft 61 (see FIG. 3) is rotated in the direction in which the recording medium 5 is conveyed from the upstream side to the downstream side in the sub-scanning direction X. As a result, the recording medium 5 rotates in the direction of arrow R2 in FIG. 7 with the second grit roller 66 as a reference point, and the recording medium 5 is placed straight as shown in FIG. 6.

[0036] As described above, according to the printer 10 of the present embodiment, the first grit roller 62 and the second grit roller 66 that convey the recording medium 5 in the sub-scanning direction X are provided on the first shaft 61 and the second shaft 65, respectively. The second shaft 65 is provided rotatably independently of the first shaft 61. That is, the first shaft 61 and the second shaft 65 are separate bodies. Therefore, compared with the case where the first grit roller 62 and the second grit roller 66 are held by one shaft, the lengths of the first shaft 61 and the second shaft 65 in the main scanning direction Y can be shortened respectively. Thereby, it is possible to suppress the occurrence of torsion in each of the first shaft 61 and the second shaft 65 when they are rotated. As a result, the recording medium 5 can be conveyed more accurately in the sub-scanning direction X.

[0037] In the printer 10 of the present embodiment, the control device 80 includes a first detection unit 82 that detects the first inclination amount of the recording medium 5 based on the position information of the crop marks 8A to 8D detected by the detection device 55, a first calculation unit 83 that calculates the rotation direction and rotation speed of the first shaft 61 and the rotation direction and rotation speed of the second shaft 65, which are the first correction conditions for setting the first inclination amount to 0, and a first drive control unit 84 that controls the first drive mechanism 63 and the second drive mechanism 67 based on the first correction conditions. When the recording medium 5 on which the image 7 and the crop marks 8A to 8D are printed is placed on the platen 16 and printing is to be performed again (i.e., printing from the continuation), the recording medium 5 may be placed inclined with respect to the platen 16. If the recording medium 5 is inclined, the image will be printed on an unintended portion, which is not preferable. In the printer 10 of the present embodiment, since the first shaft 61 and the second shaft 65 can rotate independently of each other, the inclination of the recording medium 5 can be corrected by adjusting their respective rotation directions and rotation speeds. More specifically, since the first drive control unit 84 can control the first drive mechanism 63 and the second drive mechanism 67 based on the first correction conditions, even if the recording medium 5 placed on the platen 16 is inclined, its inclination can be corrected.

[0038] In the printer 10 of the present embodiment, four crop marks 8A to 8D are printed outside each of the four corners of the rectangular area 9 including the image 7, and the first detection unit 82 detects the first inclination amount based on the position information of three or more of the four crop marks 8A to 8D detected by the detection device 55. Thereby, the inclination amount of the recording medium 5 can be detected with higher accuracy.

[0039] In the printer 10 of the present embodiment, the control device 80 includes a determination unit 85 that determines whether or not the corrected first inclination amount detected by the first detection unit 82 is 0. Thereby, it can be confirmed that the inclination of the recording medium 5 has been surely corrected.

[0040] In the printer 10 of the present embodiment, the control device 80 includes a second detection unit 86 that detects a second inclination amount of the recording medium 5 that occurs when the recording medium 5 is conveyed in the sub-scanning direction X based on the position of the recording medium 5 in the main scanning direction Y detected by the detection device 55, a second calculation unit 87 that calculates the rotation direction and rotation speed of the first shaft 61 and the rotation direction and rotation speed of the second shaft 65, which are the second correction conditions for setting the second inclination amount to 0, and a second drive control unit 88 that controls the first drive mechanism 63 and the second drive mechanism 67 based on the second correction conditions. In order to print while conveying the recording medium 5 placed on the platen 16 in the sub-scanning direction X, there is a possibility that the recording medium 5 may skew when being conveyed. If the recording medium 5 skews, the image will be printed on an unintended part, which is not preferable. In the printer 10 of the present embodiment, since the first shaft 61 and the second shaft 65 can rotate independently, the skew (i.e., inclination) of the recording medium 5 can be corrected by adjusting their respective rotation directions and rotation speeds. More specifically, since the second drive control unit 88 can control the first drive mechanism 63 and the second drive mechanism 67 based on the second correction conditions, even when the recording medium 5 placed on the platen 16 skews, the skew can be corrected.

[0041] In the printer 10 of the present embodiment, a first pinch roller 72 is disposed above the first grit roller 62 and sandwiches the recording medium 5 between the first grit roller 62, and a second pinch roller 76 is disposed above the second grit roller 66 and sandwiches the recording medium 5 between the second grit roller 66. Thereby, the inclination of the recording medium 5 can be adjusted more easily.

[0042] The preferred embodiments of the present invention have been described above. However, the above-described embodiments are merely examples, and the present invention can be implemented in various other forms.

[0043] In the above-described embodiment, the number of the first grit rollers 62 provided on the first shaft 61 and the number of the second grit rollers 66 provided on the second shaft 65 were both four, but they may be one to three or five or more. Also, although the number of the first grit rollers 62 and the number of the second grit rollers 66 were the same, they may be different.

[0044] In the above-described embodiment, the detection device 55 is configured to be able to detect the crop marks printed on the recording medium 5, but the printed crop marks may be those printed by the printer 10 or those printed by another printer.

[0045] In the above-described embodiment, the first shaft 61 and the second shaft 65 are rotatably provided on the platen 16, but they may be rotatably provided on a member different from the platen 16 (for example, the base member 40).

[0046] In the above-described embodiment, the first grit roller 62 and the first shaft 61 are formed separately, but the present invention is not limited thereto. For example, as shown in FIG. 8, the first grit roller 62 may be integrally formed on the surface of the first shaft 61. The same applies to the second grit roller 66 and the second shaft 65.

Explanation of Reference Numerals

[0047] 5 Recording medium 10 Printer (inkjet printer) 16 Platen 30 Carriage 34 Ink head 55 Detection device 61 First shaft 62 First grit roller 63 First drive mechanism 65 Second shaft 66 Second grit roller 67 Second drive mechanism 72 First pinch roller 76 Second pinch roller 80 Control device

Claims

【Claim 1】 A platen having a placement surface on which a recording medium is placed; A carriage disposed above the platen and movable in the main scanning direction; An ink head mounted on the carriage for discharging ink onto the recording medium conveyed in a sub-scanning direction orthogonal to the main scanning direction; A rotatable first shaft having an axis located below the placement surface of the platen and extending in the main scanning direction; A first grit roller provided on the first shaft and at least partially protruding above the placement surface of the platen to convey the recording medium in the sub-scanning direction; A first drive mechanism for rotating the first shaft; A rotatable shaft independent of the first shaft, having an axis located below the placement surface of the platen and extending in the main scanning direction, a rotatable second shaft; A second grit roller provided on the second shaft and at least partially protruding above the placement surface of the platen to convey the recording medium in the sub-scanning direction; A second drive mechanism for rotating the second shaft; A detection device mounted on the carriage for detecting crop marks printed on the recording medium and the position of the recording medium in the main scanning direction with respect to the platen; A control device for controlling the first drive mechanism and the second drive mechanism; and The control device includes: A first detection unit for detecting a first inclination amount of the recording medium that occurs when the recording medium on which an image and the crop marks set for the image are printed is placed on the platen, based on the position information of the crop marks detected by the detection device; A first calculation unit for calculating the rotation direction and rotation speed of the first shaft and the rotation direction and rotation speed of the second shaft, which are a first correction condition for setting the first inclination amount to 0; A first drive control unit for controlling the first drive mechanism and the second drive mechanism based on the first correction condition; A second detection unit for detecting a second inclination amount of the recording medium that occurs when the recording medium is conveyed in the sub-scanning direction during printing, based on the position of the recording medium in the main scanning direction detected by the detection device; A second calculation unit for calculating the rotation direction and rotation speed of the first shaft and the rotation direction and rotation speed of the second shaft, which are a second correction condition for setting the second inclination amount to 0; A second drive control unit that controls the first drive mechanism and the second drive mechanism based on the second correction condition. The first drive control unit controls the first drive mechanism and the second drive mechanism so as to stop the first shaft and rotate the second shaft. An inkjet printer. **Claim 2** The crop marks are printed in a total of four positions, each outside of the four corners of the rectangular area including the image. The inkjet printer according to claim 1, wherein the first detection unit detects the first inclination amount based on position information of three or more of the four crop marks detected by the detection device. **Claim 3** After the first drive mechanism and the second drive mechanism are controlled based on the first correction condition, the first detection unit is based on the position information of the crop marks detected again by the detection device. Detect the corrected first inclination amount of the recording medium. The inkjet printer according to claim 1 or 2, wherein the control device includes a determination unit that determines whether or not the corrected first inclination amount is 0. **Claim 4** A first pinch roller disposed above the first grit roller and sandwiching the recording medium therebetween and the first grit roller. An inkjet printer according to any one of claims 1 to 3, further comprising a second pinch roller disposed above the second grit roller and sandwiching the recording medium therebetween and the second grit roller.

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