Inkjet printer and method for changing maintenance frequency

Abstract

To provide an inkjet printer that allows maintenance to be performed at a more suitable frequency.SOLUTION: A printer 10 includes: a maintenance device 90; and a control device 80 that controls the maintenance device 90. A height acquisition unit 86 of the control device 80 acquires a head gap HG which is a distance between a recording medium 5 and a nozzle surface 43 in a vertical direction Z. The maintenance control unit 87 changes a frequency of maintenance on the basis of the head gap HG. Thereby, for example, an ink head 40 is located at a relatively high position, and when the recording medium 5 has a relatively large thickness, excessively frequent maintenance is suppressed from being performed.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to an inkjet printer and a method for changing maintenance frequency.

Background Art

[0002] Conventionally, there has been known an inkjet printer including a mounting table on which a recording medium is mounted, an ink head that discharges photocurable ink onto the recording medium mounted on the mounting table, a light irradiation device capable of irradiating light toward the photocurable ink discharged onto the recording medium, a carriage provided with the ink head and the light irradiation device, and a maintenance device that maintains the ink head. The maintenance device includes, for example, a wiping device that wipes the nozzle surface of the ink head, a cleaning device that sucks ink from the nozzles of the ink head, and the like.

[0003] Here, generally, the light irradiated from the light irradiation device may be reflected on the recording medium or the like and cure the photocurable ink adhering to the nozzles. When the photocurable ink adhering to the nozzles cures, there is a risk of causing clogging in the nozzles. By the maintenance device performing wiping and suction regularly, the cured ink can be removed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in an inkjet printer as described above, for example, the maintenance frequency is determined based on the vertical position of the carriage. The higher the vertical position of the carriage, that is, the vertical position of the ink head, the greater the distance between the ink head and the recording medium. As a result, more light irradiated from the light irradiation device enters the ink head. At this time, the photocurable ink attached to the ink head is relatively likely to cure. Therefore, in an inkjet printer as described above, the higher the carriage is positioned, the more frequently maintenance is set to be performed. However, even when the vertical position of the carriage is the same, if the thickness of the recording medium is different, the distance between the ink head and the recording medium will be different. For example, when the thickness of the recording medium is relatively large, even if the vertical position of the ink head is relatively high, the distance between the ink head and the recording medium is relatively small. Therefore, at this time, it is relatively difficult for light to enter the ink head. Thus, if the maintenance frequency is set to be relatively high, maintenance will be performed excessively. As a result, the operations of the printer other than printing increase, the printing efficiency decreases, or the amount of ink used other than for printing increases.

[0006] The present invention has been made in view of such a point, and an object thereof is to provide an inkjet printer that performs maintenance at a more appropriate frequency.

Means for Solving the Problems

[0007] The inkjet printer according to the present invention includes a mounting table on which a recording medium is placed, nozzles that eject photocurable ink onto the recording medium placed on the mounting table, and a nozzle surface on which the nozzles are formed. The inkjet printer further includes an ink head disposed above the mounting table, a light irradiation device disposed above the mounting table that irradiates light toward the photocurable ink ejected onto the recording medium, a maintenance device that performs maintenance on the ink head, and a control device that controls the maintenance device. The control device includes a height acquisition unit that acquires a head gap, which is a vertical distance between the recording medium and the nozzle surface, and a maintenance control unit that changes the frequency at which the maintenance device performs maintenance based on the head gap acquired by the height acquisition unit.

[0008] According to the inkjet printer of the present invention, the height acquisition unit acquires a head gap, which is a vertical distance between the recording medium placed on the mounting table and the nozzle surface. The maintenance control unit changes the frequency at which the maintenance device performs maintenance based on the head gap acquired by the height acquisition unit. Therefore, for example, when the nozzle surface is disposed at a relatively high position in the vertical direction and the thickness of the recording medium is relatively large, and when the nozzle surface is disposed at a relatively low position in the vertical direction and the thickness of the recording medium is relatively small, the maintenance frequency can be made equivalent. Therefore, the maintenance frequency is more appropriately controlled.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide an inkjet printer that performs maintenance at a more appropriate frequency.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0011] Hereinafter, an inkjet printer (hereinafter 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. Also, members and parts having the same function are denoted by the same reference numerals, and duplicate explanations are omitted or simplified as appropriate.

[0012] FIG. 1 is a perspective view of a printer 10 according to the present embodiment. The printer 10 is a so-called Roll-to-Roll type inkjet printer. The printer 10 performs printing on a recording medium 5. In the following description, for convenience, the directions of the printer 10 are defined as follows. When the printer 10 is viewed from the front, the direction away from the printer 10 is the front, and the direction approaching the printer 10 is the rear. Left, right, up, and down respectively mean left, right, up, and down when the printer 10 is viewed from the front. The reference signs F, Rr, L, R, U, and D in the drawings respectively mean front, rear, left, right, up, and down. The reference sign Y in the drawings indicates the main scanning direction. Here, the main scanning direction Y is the left-right direction. The reference sign X indicates the sub-scanning direction. Here, the sub-scanning direction X is the front-rear direction and is orthogonal to the main scanning direction Y in a plan view. The reference sign Z indicates the up-down direction. The up-down direction Z is orthogonal to the main scanning direction Y in a front view. However, the above directions are only defined for convenience of explanation and do not limit the installation mode of the printer 10 at all, nor do they limit the present invention at all.

[0013] As shown in FIG. 1, the printer 10 performs printing on the recording medium 5. The printer 10 in the present embodiment is a so-called bidirectional printing printer in which an ink head 40 (see FIG. 2) described later reciprocates in the main scanning direction Y for printing. The recording medium 5 is, for example, formed in a long shape and used by being wound in a roll shape. Note that the recording medium 5 may be a sheet-like one 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, and a sealing material composed of a base paper and a release paper laminated on the base paper and coated with an adhesive. Note that the thickness of the recording medium 5 in the present embodiment is 0.3 mm. However, the thickness of the recording medium 5 is not limited thereto.

[0014] FIG. 2 is a front view of the printer 10. As shown in FIG. 2, the printer 10 includes a main body case 11, legs 12, a platen 13, a carriage moving mechanism 20, an ink head 40, a medium conveyance mechanism 50, a carriage 30, a head moving mechanism 35, an operation panel 14, and a control device 80.

[0015] The main body case 11 has a casing 11A extending in the main scanning direction Y. The main body case 11 is supported by the legs 12. The legs 12 are provided on the lower surface of the main body case 11 and extend downward from the lower surface.

[0016] The platen 13 is a member that supports the recording medium 5 during printing on the recording medium 5. The platen 13 is an example of the placement table in the present invention. The platen 13 extends in the main scanning direction Y. The platen 13 is provided on the main body case 11.

[0017] The carriage moving mechanism 20 is a mechanism that moves the carriage 30 in the main scanning direction Y. The carriage moving mechanism 20 includes a guide rail 21, a pulley 22, a pulley 23, a belt 24, and a carriage motor 25. The guide rail 21 guides the movement of the carriage 30 in the main scanning direction Y. The guide rail 21 is disposed above the platen 13. The guide rail 21 is provided on the main body case 11. The guide rail 21 extends in the main scanning direction Y. The pulley 22 is provided to the left of the left end of the guide rail 21. The pulley 23 is provided to the right of the right end of the guide rail 21. The belt 24 is wound around the pulley 22 and the pulley 23. The carriage motor 25 is connected to the pulley 23 on the right side. However, the carriage motor 25 may be connected to the pulley 22 on the left side. When the carriage motor 25 is driven and the pulley 23 rotates, the belt 24 travels between the pulley 22 and the pulley 23.

[0018] The carriage 30 is provided with a plurality of ink heads 40. FIG. 3 is a bottom view of the ink head 40. As shown in FIG. 3, the ink head 40 is formed in a shape where the length in the sub-scanning direction X is longer than the length in the main scanning direction Y. The plurality of ink heads 40 are formed in the same shape and the same size. The ink head 40 includes a plurality of first nozzles 41 arranged in the sub-scanning direction X, a plurality of second nozzles 42 arranged in the sub-scanning direction X, and a nozzle surface 43 on which the first nozzles 41 and the second nozzles 42 are formed. Since the first nozzles 41 and the second nozzles 42 are minute, in FIG. 3, the plurality of first nozzles 41 and the plurality of second nozzles 42 are represented by straight lines. The first nozzles 41 and the second nozzles 42 of the ink head 40 discharge photocurable ink onto the recording medium 5 (see FIG. 2). In the present embodiment, the printer 10 is provided with four ink heads 40, but the number of ink heads 40 is not limited to four. Further, the ink head 40 includes two rows of nozzles of the first nozzles 41 and the second nozzles 42, but may include one row of nozzles or three or more rows of nozzles.

[0019] The photocurable ink has the property of curing when irradiated with light (for example, ultraviolet light or infrared light). The photocurable ink (for example, ultraviolet curable ink or infrared curable ink) includes a colorant such as a pigment, a photopolymerizable monomer, and a photoinitiator, and may include various other additives as necessary, for example, a photosensitizer, a polymerization inhibitor, a scavenger, an antioxidant, an ultraviolet absorber, a plasticizer, a surfactant, a leveling agent, a thickener, a dispersant, an antifoaming agent, a preservative, a solvent, etc. The photocurable ink is a colored ink. The photocurable ink is, for example, process color ink or white ink. For example, examples of the process color ink include cyan ink, magenta ink, yellow ink, black ink, light cyan ink, light magenta ink, etc. Note that the photocurable ink may be a colorless ink. Examples of the photocurable ink include ultraviolet curable ink.

[0020] As shown in FIG. 2, the light irradiation device 61 is provided on the carriage 30. The light irradiation device 61 is disposed above the platen 13. The light irradiation device 61 irradiates light (typically ultraviolet light) toward the photocurable ink ejected onto the recording medium 5. Thereby, an ink layer is formed on the recording medium 5. In the present embodiment, the light irradiation devices 61 are respectively disposed one on the right side and one on the left side of the ink head 40. However, the number of the light irradiation devices 61 is not particularly limited. The carriage 30 may be provided with one or three or more light irradiation devices 61. Further, the light irradiation device 61 may not be provided on the carriage 30. The light irradiation device 61 may be installed at a position where it can irradiate light to the recording medium 5 placed on the platen 13. Here, as shown in FIG. 3, each of the light irradiation devices 61 includes a plurality of ultraviolet irradiation LEDs 63. The plurality of ultraviolet irradiation LEDs 63 are arranged side by side in the main scanning direction Y and the sub-scanning direction X. However, the arrangement of the ultraviolet irradiation LEDs 63 is not limited thereto. The ultraviolet irradiation LEDs 63 may be arranged side by side only in one of the main scanning direction Y and the sub-scanning direction X, or only one ultraviolet irradiation LED 63 may be arranged.

[0021] As shown in FIG. 2, the printer 10 includes a medium conveyance mechanism 50. The medium conveyance mechanism 50 is a mechanism that moves the recording medium 5 placed on the platen 13 in the sub-scanning direction X. The medium conveyance mechanism 50 includes a grit roller 51, a pinch roller 52, and a feed motor 53. The grit roller 51 is provided on the platen 13. Here, a part of the grit roller 51 is embedded in the platen 13. The pinch roller 52 is disposed above the grit roller 51 so as to face the grit roller 51 in the vertical direction Z. The pinch roller 52 is a member that presses the recording medium 5 from above. The pinch roller 52 may be configured to be movable in the vertical direction Z according to the thickness of the recording medium 5. Note that the arrangement positions and numbers of the grit roller 51 and the pinch roller 52 are not particularly limited. The feed motor 53 is connected to the grit roller 51. When the feed motor 53 is driven and the grit roller 51 rotates with the recording medium 5 sandwiched between the grit roller 51 and the pinch roller 52, the recording medium 5 is conveyed in the sub-scanning direction X.

[0022] The carriage 30 is attached to the belt 24. The carriage 30 is engaged with the guide rail 21 and is slidably provided on the guide rail 21. A plurality of ink heads 40 and a light irradiation device 61 are mounted on the carriage 30. When the belt 24 travels by driving the carriage motor 25, the carriage 30 moves in the main scanning direction Y. Accordingly, the plurality of ink heads 40 and the plurality of light irradiation devices 61 mounted on the carriage 30 move in the main scanning direction Y. Note that the speed when the belt 24 travels and the ink heads 40 and the light irradiation device 61 move in the main scanning direction Y, that is, the rotation speed of the carriage motor 25, is predetermined.

[0023] FIG. 4 is a front view of the carriage 30 and the ink head 40. FIG. 5 is a side view of the carriage 30. As shown in FIGS. 4 and 5, the carriage 30 is provided with a head moving mechanism 35 for moving the ink head 40 in the vertical direction Z. By the head moving mechanism 35, the position of the ink head 40 in the vertical direction Z with respect to the platen 13 (see FIG. 2) changes. As shown in FIG. 4, the head moving mechanism 35 includes a fixed member 36, a movable member 37 movable in the vertical direction Z with respect to the fixed member 36, a spring 38, a rotating shaft 39, cams 39a and 39b, a lever 63, a first detection sensor 64 (see FIG. 5), and a second detection sensor 65. The fixed member 36 is a member that engages with the guide rail 21 (see FIG. 2) and does not move in the vertical direction Z. The fixed member 36 is provided with a cover 36a that covers the ink head 40 from the front and above. A slide plate 36b extending in the vertical direction Z is disposed at the front portion of the fixed member 36.

[0024] The ink head 40 is provided on the movable member 37. When the movable member 37 moves downward with respect to the fixed member 36, the ink head 40 moves downward. When the movable member 37 moves upward with respect to the fixed member 36, the ink head 40 moves upward. The movable member 37 has a slide plate 37a and a support plate 37b (see FIG. 5). The slide plate 37a is disposed in front of the slide plate 36b of the fixed member 36 and slides in the vertical direction Z with respect to the slide plate 36b. The upper end of the slide plate 37a is located below the upper end of the slide plate 36b. In the present embodiment, left cam support portions 37L and right cam support portions 37R extending forward are provided at the upper ends of the left and right ends of the slide plate 37a, respectively.

[0025] As shown in FIG. 5, the support plate 37b supports the ink head 40. The support plate 37b extends forward from the lower end of the slide plate 37a (see FIG. 4). As shown in FIG. 3, in the present embodiment, a fitting hole 37ba is formed in the support plate 37b. In the present embodiment, a plurality (here, four) of fitting holes 37ba are formed in the support plate 37b, and the four fitting holes 37ba are arranged in the main scanning direction Y. With the ink head 40 fitted into the fitting hole 37ba, the support plate 37b supports the ink head 40. Here, when the ink head 40 is fitted into the fitting hole 37ba, the nozzle surface 43 of the ink head 40 is positioned below the support plate 37b.

[0026] The spring 38 shown in FIG. 4 biases the movable member 37 upward. Here, the spring 38 is connected to the slidable plate 36b of the fixed member 36 and the slide plate 37a of the movable member 37, and is configured to pull the movable member 37 upward. The spring 38 is installed in a stretched state. In the present embodiment, the number of springs 38 is two, but the number of springs 38 is not particularly limited.

[0027] As shown in FIG. 4, the rotation shaft 39 extends in the main scanning direction Y and is rotatably provided with respect to the fixed member 36. In the present embodiment, the rotation shaft 39 is bridged between the left flange 36bL and the right flange 36bR of the slidable plate 36b. Here, the left end portion of the rotation shaft 39 is arranged to the left of the left flange 36bL and protrudes leftward from the left flange 36bL.

[0028] The cams 39a and 39b are provided on the rotation shaft 39 and rotate together with the rotation shaft 39. That is, the rotation shaft 39 is inserted through the cams 39a and 39b in the main scanning direction Y. The cam 39a is provided at a position overlapping the left cam support portion 37L in a plan view. The cam 39b is provided at a position overlapping the right cam support portion 37R in a plan view.

[0029] Although detailed drawings are omitted, cams 39a and 39b each have at least three end faces. In the radial direction of cams 39a and 39b, the respective distances from the center of the rotation direction of cams 39a and 39b to the three end faces are different. Among the end faces, one of them is in contact with the left cam support portion 37L and the right cam support portion 37R. Therefore, when cams 39a and 39b rotate and the end faces in contact with the left cam support portion 37L and the right cam support portion 37R change, the height of the ink head 40 in the vertical direction Z changes. In the present embodiment, as shown in FIG. 5, the end faces of cams 39a and 39b are configured such that the position of the lower end of the ink head 40, that is, the position of the nozzle surface 43 in the vertical direction Z, can be changed to the first position P1, the second position P2, and the third position P3. The second position P2 is a position above the first position P1. The third position P3 is a position above the second position P2. In the present embodiment, the first position P1 is a position 2.2 mm above the platen 13. The second position P2 is a position 2.7 mm above the platen 13. The third position P3 is a position 3.2 mm above the platen 13. However, the positions of the first position P1, the second position P2, and the third position P3 are not limited to this. Also, the number of positions where the ink head 40 moves is not limited to three. The ink head 40 may be configured to move to two positions different from each other in the vertical direction Z, or may be configured to move to four or more positions different from each other.

[0030] As shown in FIG. 5, the lever 63 is operated by the user and rotates the rotating shaft 39 and cams 39a and 39b (see FIG. 4) to change the position of the ink head 40. The lever 63 includes a rotating portion 63a and an operating portion 63b.

[0031] The rotating part 63a has a substantially circular shape. The left end of the rotating shaft 39 is connected to the rotating part 63a and is supported so as to be rotatable together with the rotating part 63a. The rotating part 63a is provided with a first shielding part 63aa, a second shielding part 63ab, and a third shielding part 63ac. The first to third shielding parts 63aa to 63ac extend around the rotating shaft 39. The first to third shielding parts 63aa to 63ac are arranged in the clockwise order of the first shielding part 63aa, the second shielding part 63ab, and the third shielding part 63ac with the rotating shaft 39 as the axis. Details of the arrangement of the first to third shielding parts 63aa to 63ac when the rotating part 63a rotates will be described later.

[0032] The operating part 63b extends forward and downward from the rotating part 63a. The operating part 63b is curved downward as it goes toward the front end. By moving the operating part 63b upward, the rotating part 63a, the rotating shaft 39, and the cams 39a, 39b (see FIG. 4) rotate from the rear to the front. As a result, the ink head 40 can be moved upward. By moving the operating part 63b downward, the rotating part 63a, the rotating shaft 39, and the cams 39a, 39b rotate from the rear to the front. As a result, the ink head 40 can be moved downward. Therefore, by operating the operating part 63b, the position of the nozzle surface 43 of the ink head 40 in the vertical direction Z can be switched between the first position P1, the second position P2, and the third position P3.

[0033] The first detection sensor 64 and the second detection sensor 65 are configured to be able to detect the first to third shielding portions 63aa to 63ac. The first detection sensor 64 and the second detection sensor 65 turn the signal ON or OFF depending on whether they detect the first to third shielding portions 63aa to 63ac. The first detection sensor 64 and the second detection sensor 65 are electrically connected to a control device 80 (see FIG. 2). The signals emitted by the first detection sensor 64 and the second detection sensor 65 are transmitted to the control device 80. In the present embodiment, the first detection sensor 64 and the second detection sensor 65 detect the position of the ink head 40 in the vertical direction Z by detecting the rotational positions of the first to third shielding portions 63aa to 63ac. The types of the first detection sensor 64 and the second detection sensor 65 are not particularly limited, but here they are photo sensors. The first detection sensor 64 and the second detection sensor 65 have the same configuration. As shown in FIG. 4, the second detection sensor 65 has a light emitting portion 65a that emits light and a light receiving portion 65b that faces the light emitting portion 65a and receives the light emitted from the light emitting portion 65a. In FIG. 4, the illustration of the first detection sensor 64 is omitted, but the first detection sensor 64 also includes a light emitting portion and a light receiving portion, similar to the second detection sensor 65. The first detection sensor 64 and the second detection sensor 65 are arranged side by side in the front-rear direction, and the first detection sensor 64 is arranged behind the second detection sensor 65.

[0034] In this embodiment, as shown by the solid line in FIG. 5, when the operation portion 63b of the lever 63 is disposed at the lowermost position, the ink head 40 is disposed at the first position P1. FIG. 6 is a table showing the position in the vertical direction Z of the ink head 40 corresponding to the states of the signals of the first detection sensor 64 and the second detection sensor 65. As shown by the solid line in FIG. 5, when the ink head 40 is disposed at the first position P1, the first detection sensor 64 detects the first shielding portion 63aa, and the second detection sensor 65 is in a state where it does not detect any of the first to third shielding portions 63aa to 63ac. At this time, as in pattern A shown in FIG. 6, the signal of the first detection sensor 64 is ON, and the signal of the second detection sensor is OFF. In FIG. 5, when the operation portion 63b is moved upward and the ink head 40 is disposed at the second position P2, the first to third shielding portions 63aa to 63ac rotate counterclockwise about the rotation axis 39. At this time, the first detection sensor 64 and the second detection sensor 65 are in a state where they do not detect any of the first to third shielding portions 63aa to 63ac. Therefore, as in pattern B shown in FIG. 6, the signals of the first detection sensor 64 and the second detection sensor 65 are OFF. In FIG. 5, when the operation portion 63b is further moved upward and the ink head 40 is disposed at the third position P3, the first to third shielding portions 63aa to 63ac further rotate counterclockwise about the rotation axis 39. At this time, the first detection sensor 64 does not detect any of the first to third shielding portions 63aa to 63ac, and the second detection sensor 65 is in a state of detecting the third shielding portion 63ac. Therefore, as in pattern C shown in FIG. 6, the signal of the first detection sensor 64 is OFF, and the signal of the second detection sensor is ON. As described above, the first to third shielding portions 63aa to 63ac are arranged so that it is possible to determine at which of the first position P1, the second position P2, and the third position P3 the ink head 40 is disposed based on the combination of the signal emitted by the first detection sensor 64 and the signal emitted by the second detection sensor 65. However, the arrangement of the first to third shielding portions 63aa to 63ac and the combination of the signal emitted by the first detection sensor 64 and the signal emitted by the second detection sensor 65 are not limited to this.

[0035] As shown in FIG. 3, the carriage 30 is equipped with a pattern detection sensor 75. The pattern detection sensor 75 is an example of the sensor in the present invention. The pattern detection sensor 75 is a sensor that reads an adjustment pattern PT1 (see FIG. 8) described later in order to adjust the landing position of the ink from the ink head 40 in bidirectional printing. The pattern detection sensor 75 reads the position of the boundary between the adjustment pattern PT1 and the recording medium 5. The type of the pattern detection sensor 75 is not particularly limited, but for example, it is an optical type. The pattern detection sensor 75 is, for example, a color sensor. The pattern detection sensor 75 is capable of detecting colors and is, for example, a sensor capable of expressing RGB colors.

[0036] The maintenance device 90 shown in FIG. 2 is a device for performing maintenance on the ink head 40. The maintenance device 90 is provided inside the right front cover 11R of the main body case 11 and is disposed below the vicinity of the right end of the guide rail 21. In the present embodiment, the vicinity of the right end of the guide rail 21 is referred to as the home position HP. In the present embodiment, maintenance refers to removing the hardened ink adhering to the inside of the ink head 40, the first nozzle 41, the second nozzle 42, and the nozzle surface 43 shown in FIG. 3. However, maintenance is not limited to this. FIG. 7 is a schematic diagram showing the periphery of the maintenance device 90. In FIG. 7, the light irradiation device 61 is not shown. As shown in FIG. 7, the maintenance device 90 includes a cap 91, a cap moving mechanism 92, a suction pump 93, a wiper 94, and a waste liquid tank 95.

[0037] The cap 91 is detachably provided on the ink head 40. The caps 91 are respectively attached to the ink heads 40 from below so as to cover the nozzle surface 43 during printing standby. That is, when the carriage 30 is located at the home position HP, the caps 91 are respectively attached to the ink heads 40. "Covering the nozzle surface 43" includes the case of covering all the nozzles of the first nozzle 41 (see FIG. 3) and the second nozzle 42 (see FIG. 3) and the entire nozzle surface 43, and the case of covering all the nozzles of the first nozzle 41 and the second nozzle 42 and a part of the nozzle surface 43. The printer 10 performs flushing to discharge ink toward the cap 91 with the cap 91 removed. Flushing eliminates clogging inside the ink head 40. Flushing is part of the maintenance in this embodiment.

[0038] The cap moving mechanism 92 supports the cap 91. The cap moving mechanism 92 is a mechanism that moves the cap 91 so as to be respectively detachable from the ink head 40. In this embodiment, the cap moving mechanism 92 moves the cap 91 in the vertical direction Z. The configuration of the cap moving mechanism 92 is not particularly limited. For example, a drive motor 92A is provided. The cap moving mechanism 92 moves the cap 91 in the vertical direction Z by driving the drive motor 92A. The cap moving mechanism 92 moves the cap 91 to the cap position by moving the cap 91 upward. Here, the cap position is a position where the cap 91 covers the nozzle surface 43. Thereby, the caps 91 are respectively attached to the ink heads 40. When the caps 91 are respectively attached to the ink heads 40, sealed spaces are respectively formed between the caps 91 and the nozzle surface 43. The cap moving mechanism 92 moves the cap 91 to the separated position by moving the cap 91 downward. Here, the separated position is a position where the cap 91 is separated from the nozzle surface 43. Thereby, the caps 91 are respectively removed from the ink heads 40. Note that the cap 91 may be shaped to cover a plurality of ink heads 40.

[0039] The suction pump 93 sucks the fluid (e.g., photocurable ink) inside the cap 91 when the cap 91 is attached to the ink head 40. As a result, the sealed space inside the cap 91 becomes a pressure lower than the atmospheric pressure. Consequently, the suction pump 93 sucks the photocurable ink inside the first nozzle 41 (see FIG. 3) and the second nozzle 42 (see FIG. 3) of the ink head 40. That is, the photocurable ink is forcibly discharged from the first nozzle 41 and the second nozzle 42 of the ink head 40 into the cap 91. The suction port of the suction pump 93 is connected to the cap 91. The discharge port of the suction pump 93 is connected to the waste liquid tank 95. The ink sucked by the suction pump 93 is stored in the waste liquid tank 95. The above suction is an operation to discharge the photocurable ink from the first nozzle 41 and the second nozzle 42 to eliminate the discharge failure of the first nozzle 41 and the second nozzle 42. The above suction is a part of the maintenance in this embodiment.

[0040] The wiper 94 is arranged to the left of the cap 91 and the cap moving mechanism 92. The wiper 94 is a member for wiping the nozzle surface 43 of the ink head 40. The wiper 94 is arranged below the guide rail 21. The wiper 94 is configured to contact the nozzle surface 43 when the carriage 30 passes above the wiper 94. Therefore, by moving the carriage 30 above the wiper 94 in the main scanning direction Y, the cured ink adhering to the nozzle surface 43 can be removed. The wiper 94 is a plate-like member and is formed of, for example, rubber or the like. The wiping is a part of the maintenance in this embodiment. Note that the configuration of the wiper 94 is not limited to this. For example, the wiper 94 may be configured to be movable in the main scanning direction Y and / or the vertical direction Z by a moving mechanism for moving the wiper 94.

[0041] As shown in FIG. 2, an operation panel 14 is provided in front of the right front cover 11R of the main body case 11. For example, the operation panel 14 is provided with a display unit for displaying the state of the printer and input keys operated by the user. The operation panel 14 is connected to a control device 80 that controls various operations of the printer 10.

[0042] The printer 10 includes a control device 80. The control device 80 is a device that controls printing on the recording medium 5 and the maintenance device 90. 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, 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 (read only memory) that stores a program executed by the CPU, a RAM (random access memory) used as a working area for expanding the program, and a storage device such as a memory for storing programs and various data. As shown in FIG. 2, the control device 80 is provided inside the right front cover 11R. However, the control device 80 does not have to be provided inside the right front cover 11R. For example, the control device 80 may be a computer installed outside the right front cover 11R. In this case, the control device 80 is communicably connected to the printer 10 via wire or wireless.

[0043] FIG. 8 is a block diagram of the control device 80. As shown in FIG. 8, the control device 80 is electrically connected to the operation panel 14, the carriage motor 25, the feed motor 53, the cap movement mechanism 92, the suction pump 93, the ink head 40, the light irradiation device 61, the first detection sensor 64, the second detection sensor 65, and the pattern detection sensor 75. The control device 80 includes a head height determination unit 81, an adjustment pattern printing unit 82, a detection unit 83, an adjustment value determination unit 84, a calculation unit 85, a height acquisition unit 86, and a maintenance control unit 87.

[0044] The head height determination unit 81 determines the position of the ink head 40 in the vertical direction Z shown in FIG. 5. In the present embodiment, the head height determination unit 81 determines whether the position of the nozzle surface 43 of the ink head 40 in the vertical direction Z is at any of the first position P1, the second position P2, or the third position P3. The head height determination unit 81 determines the position of the ink head 40 in the vertical direction Z based on the signal of the first detection sensor 64 and the signal of the second detection sensor 65. That is, the head height determination unit 81 determines which of the patterns A, B, and C shown in FIG. 6 the signals of the first detection sensor 64 and the second detection sensor 65 correspond to, and determines the position of the ink head 40.

[0045] The adjustment pattern printing unit 82 prints an adjustment pattern PT1 (see FIG. 9) for adjusting the landing position of the ink from the ink head 40 in bidirectional printing. FIG. 9 is an example of the adjustment pattern PT1 printed on the recording medium 5.

[0046] As shown in FIG. 9, the adjustment pattern PT1 has a first figure F1 and a second figure F2. The first figure F1 is printed when the ink head 40 moves in the main scanning direction Y from right to left. The second figure F2 is printed when the ink head 40 moves in the main scanning direction Y from left to right. The second figure F2 is printed with a predetermined interval shifted in the main scanning direction Y with respect to the first figure F1. That is, for a desired position on the recording medium 5, the distance difference between the position of the ink head 40 when printing from right to left in the main scanning direction Y and the position of the ink head 40 when printing from left to right in the main scanning direction Y is the predetermined interval. This predetermined interval is used as the adjustment value. When the adjustment value is 0, the position of the ink head 40 in the main scanning direction Y when printing the first figure F1 and the position of the ink head 40 in the main scanning direction Y when printing the second figure F2 are symmetric positions with respect to the desired position on the recording medium. The first figure F1 and the second figure F2 have the same shape and the same size. In the present embodiment, the first figure F1 and the second figure F2 are square. The first figure F1 and the second figure F2 are printed at positions aligned in the sub-scanning direction X. A pair of the first figure F1 and the second figure F2 is called an adjustment group G1. In FIG. 9, seven adjustment groups are shown. In the following description, the adjustment group G1 will be appropriately assigned reference numerals G1a to G1g in order from the left. The seven adjustment groups G1a to G1g have different adjustment values respectively. However, the adjustment pattern PT1 is not limited to this.

[0047] The detection unit 83 shown in FIG. 8 detects the adjustment pattern PT1 by the pattern detection sensor 75. When the adjustment pattern PT1 is printed on the recording medium 5, the detection unit 83 controls the carriage movement mechanism 20 and moves the carriage 30 in the main scanning direction Y above the adjustment pattern PT1 printed on the recording medium 5. At this time, the detection unit 83 controls the pattern detection sensor 75 to read the adjustment pattern PT1. The pattern detection sensor 75 reads the positions of the right and left ends of the first figure F1 and the second figure F2 shown in FIG. 9. The pattern detection sensor 75 reads the positions of the right and left ends of the first figure F1 and the second figure F2 from the color difference between the first figure F1 or the second figure F2 and the recording medium 5. The positions of the right and left ends of the first figure F1 and the second figure F2 are given by coordinates, for example.

[0048] The adjustment value determination unit 84 shown in FIG. 8 determines the adjustment value of the landing position in bidirectional printing from the adjustment pattern PT1. In the present embodiment, as shown in FIG. 9, in the adjustment set G1d, the first figure F1 and the second figure F2 are arranged side by side without a gap. That is, the deviation of the ink landing position is the smallest. At this time, the adjustment value determination unit 84 determines the adjustment value when the adjustment set G1d is ejected as the adjustment value in bidirectional printing. Note that, as in the present embodiment, when there is no adjustment set G1 in which the first figure F1 and the second figure F2 are arranged side by side without a gap, the adjustment set with the smallest gap in the main scanning direction Y between the first figure F1 and the second figure F2, or the adjustment value of the adjustment set G1 with the smallest overlap in the main scanning direction Y between the first figure F1 and the second figure F2 may be determined as the adjustment value in bidirectional printing. FIG. 10 is a front view showing the position of the ink head 40 when performing bidirectional printing for a certain ejection position TP. By determining the adjustment value, as shown in FIG. 10, the positions Y1 and Y2 of the ink head 40 in the main scanning direction Y when ejecting ink toward a certain ejection position TP on the recording medium 5 are determined. The position Y1 is the position where the ink head 40 ejects ink when moving in the main scanning direction Y from right to left. The position Y2 is the position where the ink head 40 ejects ink when moving in the main scanning direction Y from left to right. The position Y2 is adjusted in the main scanning direction Y by the adjustment value determined by the adjustment value determination unit 84.

[0049] The calculation unit 85 shown in FIG. 8 calculates the head gap HG (see FIG. 9), which is the distance between the recording medium 5 and the nozzle surface 43, based on the adjustment value by the adjustment pattern PT1. First, the calculation unit 85 obtains the distance Y3 in the main scanning direction Y between the position Y1 and the position Y2 shown in FIG. 9, the moving speed v1 of the carriage 30 in the main scanning direction Y at the position Y1, the ink ejection speed v2 from the ink head 40 at the position Y1, the moving speed v3 of the carriage 30 in the main scanning direction Y at the position Y2, and the ink ejection speed v4 from the ink head 40 at the position Y2. The distance Y3 is a value including the adjustment value in bidirectional printing. The moving speed v1 is the speed in the direction from right to left. The moving speed v3 is the speed in the direction from left to right. The ejection speeds v2 and v4 are the speeds in the vertical direction. At the position Y1, the ink ejected from the ink head 40 travels in the direction obtained by synthesizing the speeds v1 and v2. The angle formed by the traveling direction of the ink ejected from the position Y1 and the recording medium 5 is the angle θ°. At the position Y2, the ink ejected from the ink head 40 travels in the direction obtained by synthesizing the speeds v3 and v4. The angle formed by the traveling direction of the ink ejected from the position Y2 and the recording medium 5 is the angle φ°. The calculation unit calculates the head gap HG using the moving speeds v1 and v3, the ejection speeds v2 and v4, and the trigonometric ratios of the angles θ° and φ°. Note that since the head gap HG in the present embodiment is a value obtained by calculation, it may include an error with respect to the actually measured value of the distance in the vertical direction Z between the recording medium 5 and the nozzle surface 43.

[0050] The height acquisition unit 86 acquires the height of the head gap HG. In the present embodiment, the height acquisition unit 86 acquires the head gap HG which is the calculation result by the calculation unit 85. That is, the height acquisition unit 86 receives the value of the head gap HG calculated by the calculation unit 85. Note that the height acquisition unit 86 may acquire a value input by the user. For example, when the user knows the value of the head gap HG, the user may operate the operation panel 14 to input the value of the head gap HG. Also, in the present embodiment, the height acquisition unit 86 also acquires the position in the vertical direction Z of the ink head 40 determined by the head height determination unit 81. That is, the height acquisition unit 86 acquires which position among the first position P1, the second position P2, and the third position P3 the nozzle surface 43 of the ink head 40 is arranged at.

[0051] The maintenance control unit 87 changes the maintenance frequency based on the position in the vertical direction Z of the ink head 40 and the head gap HG. FIG. 11 is a table showing the maintenance frequency based on the position of the ink head 40 and the head gap HG. In the present embodiment, the maintenance frequency is changed in three levels: "High", "Middle", and "Low". "High" is a setting to execute maintenance every hour. "Middle" is a setting to execute maintenance every 1.5 hours. "Low" is a setting to execute maintenance every 2 hours. However, the time interval of maintenance is not limited to the above times. Also, the setting of the maintenance frequency is not limited to three levels.

[0052] The maintenance control unit 87 first changes the maintenance frequency based on the position of the ink head 40. The maintenance control unit 87 changes the maintenance frequency based on whether the position of the nozzle surface 43 of the ink head 40 in the vertical direction Z is any of the first position P1, the second position P2, and the third position P3. When the position of the nozzle surface 43 in the vertical direction Z is the first position P1, the maintenance control unit 87 changes the maintenance frequency to "Low". At this time, the maintenance frequency is not changed by the head gap HG. When the position of the nozzle surface 43 in the vertical direction Z is the second position P2, the maintenance control unit 87 temporarily sets the maintenance frequency to "Middle". When the position of the nozzle surface 43 in the vertical direction Z is the third position P3, the maintenance control unit 87 temporarily sets the maintenance frequency to "High".

[0053] Next, the maintenance control unit 87 changes the maintenance frequency based on the head gap HG. In the present embodiment, when the position of the nozzle surface 43 in the vertical direction Z is the second position P2 or the third position P3, whether to change the temporarily set maintenance frequency is determined based on the value of the head gap HG. When the nozzle surface 43 is disposed at the second position P2 or the third position P3 and the head gap HG is HG < 2.0 mm, the maintenance control unit 87 changes the maintenance frequency to "Low". When the nozzle surface 43 is disposed at the second position P2 and the head gap HG is 2.0 mm ≦ HG < 2.5 mm, the maintenance control unit 87 keeps the maintenance frequency as "Middle". When the head gap HG is disposed at the third position P3 and the head gap HG is 2.0 mm ≦ HG < 2.5 mm, the maintenance control unit 87 changes the maintenance frequency to "Middle". When the nozzle surface 43 is disposed at the second position P2 and the head gap HG is 2.5 mm ≦ HG, the maintenance control unit 87 keeps the maintenance frequency as "Middle". When the nozzle surface 43 is disposed at the third position P3 and the head gap HG is 2.5 mm ≦ HG, the maintenance control unit 87 keeps the maintenance frequency as "High". Here, in the present embodiment, as described above, the first position P1, the second position P2, and the third position P3 are positions 2.2 mm, 2.7 mm, and 3.2 mm above the platen 13 (see FIG. 5), respectively. Also, the thickness of the recording medium 5 is 0.3 mm. Therefore, when the nozzle surface 43 is disposed at the first position P1, the conditions where 2.0 mm ≦ HG < 2.5 mm and 2.5 mm ≦ HG do not occur for the head gap HG. Also, when the nozzle surface 43 is disposed at the second position P2, the condition where 2.5 mm ≦ HG does not occur for the head gap HG. In FIG. 11, "(-)" is described at locations corresponding to conditions that do not occur in the present embodiment. However, the threshold value of the head gap HG for determining the maintenance frequency is not limited to the values described above.

[0054] The configuration of the printer 10 according to the present embodiment has been described above. Next, a procedure for changing the maintenance frequency of the printer 10 will be described. FIG. 12 is a flowchart showing the procedure for changing the maintenance frequency of the printer 10.

[0055] In step S101, the height in the vertical direction Z of the nozzle surface 43 of the ink head 40 is set and determined. By the user moving the operation portion 63b of the lever 63 provided in the head movement mechanism 35 in the vertical direction Z, the nozzle surface 43 is disposed at any one of a first position P1, a second position P2, and a third position P3. When the position of the nozzle surface 43 in the vertical direction Z is determined, the head height determination unit 81 determines the position of the nozzle surface 43 of the ink head 40 in the vertical direction Z. The head height determination unit 81 determines which of the patterns A, B, and C shown in FIG. 6 the signal of the first detection sensor 64 and the signal of the second detection sensor 65 correspond to. Note that in step S101, when it is not necessary to move the ink head 40 in the vertical direction Z, the ink head 40 does not have to be moved in the vertical direction Z. The recording medium 5 is placed on the platen 13 either before or after step S101. Alternatively, the recording medium 5 may be placed on the platen 13 during step S101.

[0056] In step S102, the adjustment pattern printing unit 82 controls the carriage movement mechanism 20, the medium conveyance mechanism 50, and the ink head 40 to print an adjustment pattern PT1 on the recording medium 5. Note that the adjustment value for each adjustment set G1 is determined in advance. In step S103, the detection unit 83 controls the carriage movement mechanism 20 to move the carriage 30 in the main scanning direction Y. At this time, the pattern detection sensor 75 detects the adjustment pattern PT1. As described above, the pattern detection sensor 75 detects the positions of the right end and the left end of the first figure F1 and the second figure F2.

[0057] In step S104, the adjustment value determination unit 84 determines the adjustment value in bidirectional printing. In the present embodiment, as described above, the adjustment value when the adjustment set G1d shown in FIG. 8 is printed is determined as the adjustment value in bidirectional printing. By the adjustment value determination unit 84 determining the adjustment value in bidirectional printing, the positions Y1 and Y2 shown in FIG. 9 are determined. In step S105, the calculation unit 85 calculates the head gap HG using the moving speeds v1 and v3, the ejection speeds v2 and v4, and the trigonometric ratios of the angles θ° and φ°.

[0058] In step S106, the height acquisition unit 86 acquires the position in the vertical direction Z of the ink head 40 determined by the head height determination unit 81 and the head gap HG acquired by the calculation unit 85.

[0059] In step S107, the maintenance control unit 87 changes the maintenance frequency. As shown in FIG. 11, when the position of the nozzle surface 43 is the first position P1, the maintenance control unit 87 changes the maintenance frequency to "Low". At this time, regardless of the value of the head gap HG, the maintenance frequency is changed to "Low". When the position of the nozzle surface 43 is the second position P2, the maintenance control unit 87 temporarily sets the maintenance frequency to "Middle". When the position of the nozzle surface 43 is the third position P3, the maintenance control unit 87 temporarily sets the maintenance frequency to "High". Next, the maintenance control unit 87 changes the maintenance frequency based on the value of the head gap HG. As described above, when the nozzle surface 43 is arranged at the second position P2 or the third position P3 and the head gap HG is HG < 2.0 mm, the maintenance control unit 87 changes the maintenance frequency from "Middle" or "High" to "Low". When the nozzle surface 43 is arranged at the second position P2 and the head gap HG is 2.0 mm ≤ HG < 2.5 mm, the maintenance control unit 87 keeps the maintenance frequency as "Middle". When the nozzle surface 43 is arranged at the third position P3 and the head gap HG is 2.0 mm ≤ HG < 2.5 mm, the maintenance control unit 87 changes the maintenance frequency from "High" to "Middle". When the nozzle surface 43 is arranged at the second position P2 and the head gap HG is 2.5 mm ≤ HG, the maintenance control unit 87 keeps the maintenance frequency as "Middle". However, as described above, in this embodiment, the conditions at this time do not occur. When the nozzle surface 43 is arranged at the third position P3 and the head gap HG is 2.5 mm ≤ HG, the maintenance control unit 87 keeps the maintenance frequency as "High".

[0060] As described above, according to the printer 10 of the present embodiment, the maintenance control unit 87 changes the frequency at which the maintenance device 90 performs maintenance based on the value of the head gap HG acquired by the height acquisition unit 86. Thus, for example, even if the nozzle surface 43 of the ink head 40 is disposed at the second position P2, if the head gap HG is less than 2.0 mm, the maintenance frequency is changed to "Low". At this time, since the head gap HG is relatively small, even if the maintenance frequency is "Low", clogging of the cured ink hardly occurs in the ink head 40. Therefore, it is possible to make the maintenance frequencies the same between the case where the position of the ink head 40 in the vertical direction Z is disposed at a relatively high position and the thickness of the recording medium 5 is relatively large, and the case where the position of the ink head 40 in the vertical direction is disposed at a relatively low position and the thickness of the recording medium 5 is relatively small. Therefore, when the head gap HG is relatively small, excessive maintenance is suppressed from being performed. That is, the printer 10 performs maintenance at a more appropriate frequency.

[0061] According to the printer 10 of the present embodiment, the head movement mechanism 35 moves the ink head 40 in the vertical direction Z. The maintenance control unit 87 changes the maintenance frequency based on the position of the ink head 40 in the vertical direction Z and the head gap HG. At this time, the maintenance control unit 87 can temporarily set the maintenance frequency according to the position of the ink head 40 in the vertical direction Z, and determine whether to change from the temporarily set frequency based on the value of the head gap HG. Therefore, the printer 10 can change to a more appropriate maintenance frequency.

[0062] According to the printer 10 of this embodiment, the head movement mechanism 35 switches the position of the nozzle surface 43 in the vertical direction Z between a first position P1 and a second position P2. The second position P2 is above the first position P1. In this embodiment, when the nozzle surface 43 is disposed at the first position P1, the maintenance frequency is changed to "Low". Also, when the nozzle surface 43 is disposed at the second position P2, the maintenance frequency is temporarily set to "Middle" in a state before considering the value of the head gap HG. Thereby, the change of the maintenance frequency based on the position of the ink head 40 in the vertical direction Z is simplified.

[0063] According to the printer 10 of this embodiment, when the position of the nozzle surface 43 of the ink head 40 in the vertical direction Z is disposed at the second position P2 or the third position P3, the maintenance control unit 87 changes the maintenance frequency based on the position of the ink head 40 in the vertical direction Z and the head gap HG. In this embodiment, when the ink head 40 is disposed at the first position P1, the maintenance frequency is not changed according to the head gap HG. Here, when the ink head 40 is disposed at the first position P1 and is disposed at a relatively low position in the vertical direction Z, the distance between the nozzle surface 43 and the platen 13 is relatively short. Therefore, regardless of the thickness of the recording medium 5 placed on the platen 13, the amount of light entering the nozzle surface 43 from the light irradiation device 61 is relatively small. Therefore, even if the maintenance frequency is set to "Low" regardless of the head gap HG, the states of the first nozzle 41 and the second nozzle 42 of the ink head 40 can be kept good. Therefore, when the ink head 40 is disposed at the second position P2 or the third position P3, which is a relatively high position in the vertical direction Z, the maintenance frequency may be set based on the head gap HG. Thereby, the change of the maintenance frequency can be simplified.

[0064] According to the printer 10 of this embodiment, the adjustment pattern printing unit 82 prints the adjustment pattern PT1 on the recording medium 5. The value of the head gap HG acquired by the height acquisition unit 86 is a value obtained based on the adjustment pattern PT1. Here, the adjustment pattern PT1 is performed before printing starts in order to prevent deterioration of the quality of the printed matter when performing bidirectional printing. Therefore, it is possible to adjust the landing position of the ink in bidirectional printing and acquire the value of the head gap HG. As a result, the printer 10 does not operate only for acquiring the head gap HG. Therefore, by changing the maintenance frequency, an increase in operations other than printing is suppressed, and a decrease in the printing efficiency of the printer 10 is suppressed.

[0065] The printer 10 of this embodiment includes a pattern detection sensor 75 that reads the adjustment pattern PT1. The adjustment value in bidirectional printing is determined based on the landing position read by the pattern detection sensor 75. The calculation unit 85 calculates the head gap HG from the adjustment value. Thereby, the control device 80 reads the adjustment pattern PT1, calculates the head gap HG, and performs the operations until the maintenance frequency is changed. Therefore, a series of operations until the maintenance frequency is changed can be automatically performed.

[0066] The technology disclosed here can be applied to various types of printers. In addition to the Roll-to-Roll type printer shown in the above-described embodiment, for example, it can be similarly applied to a so-called flatbed type printer that fixes the recording medium on a table and transports and prints the table. It can also be similarly applied to a so-called gantry type printer that places the recording medium on a table and moves the carriage in the main scanning direction Y and the front-rear direction with respect to the table for printing.

Explanation of Signs

[0067] 5 Recording medium 10 Printer (inkjet printer) 13 Platen (mounting table) 40 Ink head 41 First nozzle 42 Second nozzle 43 Nozzle surface 80 Control device 86 Height acquisition unit 87 Maintenance control unit 90 Maintenance device HG Head gap

Claims

1. A mounting table on which a recording medium is placed, a nozzle that discharges photocurable ink onto the recording medium placed on the mounting table, and a nozzle surface on which the nozzle is formed, and an ink head disposed above the mounting table, a light irradiation device that is disposed above the mounting table and irradiates light toward the photocurable ink discharged onto the recording medium, a maintenance device that performs maintenance on the ink head, a control device that controls the maintenance device, and the control device includes a height acquisition unit that acquires a head gap, which is a vertical distance between the recording medium and the nozzle surface, and a maintenance control unit that changes the frequency at which the maintenance device performs the maintenance based on the head gap acquired by the height acquisition unit. An inkjet printer.

2. and includes a head moving mechanism that relatively moves the mounting table and the ink head in the vertical direction, wherein the maintenance control unit changes the frequency of performing the maintenance based on the vertical position of the ink head and the head gap. The inkjet printer according to claim 1.

3. The head moving mechanism switches the vertical position of the ink head between a first position and a second position that is above the first position. The inkjet printer according to claim 2.

4. The maintenance control unit changes the frequency of performing the maintenance based on the vertical position of the ink head and the head gap when the vertical position of the ink head is higher than a predetermined height. The inkjet printer according to claim 2.

5. The control device includes an adjustment pattern printing unit that prints an adjustment pattern printed on the recording medium for adjusting the landing position of the photocurable ink from the ink head in bidirectional printing, wherein the height acquisition unit acquires the head gap calculated based on the adjustment pattern. The inkjet printer according to claim 1.

6. and includes a sensor that reads the adjustment pattern printed by the adjustment pattern printing unit, wherein the control device includes a calculation unit that calculates the head gap based on the landing position of the adjustment pattern read by the sensor. The inkjet printer according to claim 5.

7. A maintenance frequency changing method for changing the frequency of maintenance of a nozzle surface on which a nozzle for discharging a photocurable ink is formed and which is placed on a mounting table, a height acquisition step of acquiring a head gap which is a vertical distance between the recording medium and the nozzle surface, and a frequency change step of changing the frequency of performing the maintenance based on the head gap acquired in the height acquisition step. The maintenance frequency changing method includes these steps.

Images