Printer

Abstract

To properly execute a cleaning processing to an ink head while suppressing the consumption of an ink.SOLUTION: A printer 10 is equipped with a plurality of ink heads 22 that has a nozzle surface 23 formed with a nozzle 24 discharging ink, and a control device 90. The control device 90 is equipped with a deciding portion 93 that decides a cleaning interval T1 about each ink head 22 according to a viscosity increase degree A1 of the ink adhered to the nozzle surface 23, an obtaining portion 95 that obtains an accumulation printing time T2 in the ink heads 22 from a previous cleaning processing P1, a determining portion 97 that determines whether or not the accumulation printing time T2 is the cleaning interval T1 or more, and a cleaning executing portion 99 that executes the cleaning processing P1 to the ink head 22 which is determined by the determining portion 97 that the accumulation printing time T2 is the cleaning interval T1 or more.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a printer. [Background technology]

[0002] For example, Patent Document 1 discloses an inkjet recording device that includes multiple ink heads that eject ink toward a recording medium, an ultraviolet irradiation device that irradiates ultraviolet rays onto the ink that has landed on the recording medium, and a carriage on which the ink heads and the ultraviolet irradiation device are mounted.

[0003] The ink head has a nozzle surface. Ink discharged from the ink head may adhere to the nozzle surface. Ultraviolet light emitted from the ultraviolet light irradiation device may be reflected by the recording medium and irradiated to the nozzle surface. When the ink adhered to the nozzle surface is irradiated with ultraviolet light, the ink is likely to harden on the nozzle surface. When the ink adhered to the nozzle surface hardens, there is a risk of ink discharge failure occurring. Therefore, in the inkjet recording device disclosed in Patent Document 1, a maintenance unit for maintaining the ink head is provided to suppress discharge failure caused by hardening of the ink adhered to the nozzle surface.

[0004] Incidentally, there are various types of recording media onto which ink is ejected. Depending on the type of recording media, some reflect ultraviolet light easily, while others do not. Therefore, the ease with which ink attached to the nozzle surface hardens varies depending on the type of recording media. Therefore, in the inkjet recording device disclosed in Patent Document 1, a maintenance interval is set according to the type of recording media to be printed, and maintenance is periodically performed on all ink heads at once based on the interval set as the maintenance interval. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-297230 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the inkjet recording apparatus disclosed in Patent Document 1 is provided with a plurality of ink heads as described above. The amount of ultraviolet light irradiated from the ultraviolet irradiation device differs for each ink head, and the degree of hardening of the ink attached to the nozzle surface (in other words, the ease of hardening) differs. Since the maintenance unit performs maintenance on a plurality of ink heads collectively, some ink heads may be maintained even if the ink attached to the nozzle surface is not hardened. Since ink is consumed in the maintenance of the ink heads, it is preferable to keep the amount of ink consumption as low as possible.

[0007] The present invention has been made in consideration of the above-mentioned problems, and has as its object to provide a printer that is capable of appropriately performing a cleaning process on the ink head while suppressing the amount of ink consumption. [Means for solving the problem]

[0008] The printer according to the present invention includes a plurality of ink heads, a cap unit, a wiper unit, and a control device. The ink head has a nozzle surface on which nozzles for ejecting ink are formed. The cap unit includes a cap attached to the ink head so as to cover the nozzles, a capping mechanism for attaching and detaching the cap to and from the ink head, and a suction pump connected to the cap. The wiper unit includes a wiper for wiping the nozzle surface, and a wiping mechanism for moving the wiper or the ink head while the wiper is in contact with the nozzle surface. A cleaning process is a process for performing at least one of a suction process for ejecting ink from the nozzles while the cap is attached to the ink head, and a wiping process for wiping the nozzle surface with the wiper. The control device includes a determination unit, an acquisition unit, a judgment unit, and a cleaning execution unit. The determination unit determines a cleaning interval for each ink head according to the degree of viscosity increase of the ink attached to the nozzle surface. The acquisition unit acquires the cumulative printing time of the ink head since the previous cleaning process. The determining unit determines whether the accumulated printing time is equal to or longer than the cleaning interval. The cleaning execution unit executes the cleaning process on the ink head for which the determining unit determines that the accumulated printing time is equal to or longer than the cleaning interval.

[0009] According to the above printer, the cleaning process is preferably performed on an ink head where the ink adhering to the nozzle surface has become viscous. In the present invention, the timing for performing the cleaning process on the ink head is determined by a cleaning interval for each ink head that is determined according to the degree of viscosity increase of the ink adhering to the nozzle surface. Therefore, the cleaning process can be performed for each ink head at the timing when the ink adhering to the nozzle surface becomes viscous. Therefore, since the cleaning process is performed for each ink head at the appropriate timing when the ink becomes viscous, it is possible to reduce the execution of unnecessary cleaning processes on the ink head, and to reduce the amount of ink consumed by the cleaning process. Effect of the Invention

[0010] According to the present invention, it is possible to provide a printer that is capable of appropriately performing a cleaning process on an ink head while suppressing the amount of ink consumption. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view showing a printer according to a first embodiment. [Diagram 2] FIG. 2 is a front view of the printer with the cover open. [Diagram 3] 1 is a block diagram of a printer according to a first embodiment. [Figure 4] FIG. 2 is a bottom view showing the carriage, the ink head, and the light irradiation device. [Diagram 5] FIG. 4 is a front view showing a carriage and a cap unit. [Figure 6] FIG. 4 is a front view showing a carriage and a cap unit. [Figure 7] FIG. 4 is a front view showing the carriage and the wiper unit. [Figure 8] 10 is a flowchart illustrating an example of a cleaning process. [Figure 9]FIG. 4 is a diagram showing the distance from a light irradiation device, the amount of irradiated light, the degree of ink viscosity increase, and the cleaning interval for each ink head in the first embodiment. [Figure 10] 10 is a flowchart showing a control process up to the execution of a cleaning process. [Figure 11] FIG. 11 is a bottom view showing a carriage, an ink head, and a light irradiation device in the second embodiment. [Figure 12] FIG. 11 is a diagram showing the color of ink ejected, the minimum distance from the light irradiation device, the amount of irradiated light, the degree of ink viscosity increase, and the cleaning interval for each ink head in the second embodiment. [Figure 13] FIG. 11 is a front view showing a carriage, an ink head, a light irradiation device, and a wiper of a wiper unit in a third embodiment. [Figure 14] FIG. 11 is a diagram showing the distance from a light irradiation device, the amount of irradiated light, the degree of ink viscosity increase, and the cleaning interval for each ink head in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a printer according to the present invention will be described with reference to the drawings. Note that the embodiment described here is, of course, not intended to limit the present invention in any particular way. Also, the same reference numerals are used for members and parts that perform the same functions, and duplicated descriptions will be omitted or simplified as appropriate.

[0013] First Embodiment First, the printer 10 according to the first embodiment will be described. FIG. 1 and FIG. 2 are a perspective view and a front view, respectively, of the printer 10 according to the present embodiment. FIG. 3 is a block diagram of the printer 10 according to the present embodiment. In the following, the symbols F, Rr, L, R, U, and D in the drawings indicate the front, rear, left, right, top, and bottom of the printer 10, respectively. Furthermore, the symbols X and Y indicate the transport direction and the scanning direction, respectively. For example, the scanning direction Y is the left-right direction. The transport direction X intersects with the scanning direction Y in a plan view, and is perpendicular here. The transport direction X is, for example, the front-rear direction. However, these directions are merely defined for the convenience of explanation, and do not limit the installation mode of the printer 10 in any way.

[0014] As shown in FIG. 2, the printer 10 ejects ink onto a printing substrate 5 to perform printing on the printing substrate 5. The printing substrate 5 is, for example, recording paper. However, the printing substrate 5 is not limited to recording paper. For example, the printing substrate 5 includes relatively thick objects such as sheets made of resin materials such as PVC and polyester, metal plates, glass plates, and wooden plates. The printing substrate 5 may also be a three-dimensional object such as a smartphone case.

[0015] The printer 10 is an inkjet printer. In this embodiment, the printer 10 is a so-called flatbed type printer, and as a support base 40 described below moves in the transport direction X, the printing substrate 5 also moves in the transport direction X. However, the printer 10 may be a so-called roll-to-roll type printer, and may be one in which only the roll-shaped printing substrate 5 moves in the transport direction X.

[0016] As shown in Fig. 1, the printer 10 includes a case 11 and a cover 12. The case 11 has a rectangular parallelepiped shape and has an internal space. Printing is performed on a printing medium 5 in the internal space. As shown in Fig. 2, an opening 15 is formed in the front of the case 11.

[0017] The cover 12 is supported by the case 11 so that the opening 15 can be freely opened and closed. The cover 12 is configured to be rotatable around the rear end as an axis. As shown in FIG. 1, a window 16 is provided in the front and upper parts of the cover 12. The window 16 is formed of a transparent or translucent member, for example, an acrylic plate. A user can view the internal space of the case 11 through the window 16.

[0018] Next, a description will be given of the internal configuration of the printer 10. As shown in Fig. 2, the printer 10 includes a guide rail 18, a carriage 20, an ink head 22, a light irradiation device 30, and a support base 40.

[0019] The guide rail 18 is fixed to the case 11 in the internal space of the case 11. The guide rail 18 extends in the scanning direction Y. The carriage 20 is slidably engaged with the guide rail 18. The carriage 20 is configured to be movable in the scanning direction Y along the guide rail 18.

[0020] The ink head 22 ejects ink onto the printing substrate 5 supported by the support base 40. The ink head 22 is provided on the carriage 20. The ink head 22 is configured to be movable in the scanning direction Y together with the carriage 20. The number of ink heads 22 is not particularly limited. In this embodiment, the number of ink heads 22 is four. The four ink heads 22 are arranged side by side in the scanning direction Y. FIG. 4 is a bottom view showing the carriage 20, the ink head 22, and the light irradiation device 30. Here, as shown in FIG. 4, the four ink heads 22 are also referred to as the first ink head 22A, the second ink head 22B, the third ink head 22C, and the fourth ink head 22D, from the left.

[0021] The ink head 22 has a first ink head 22A, a second ink head 22B, a third ink head 22C, and a fourth ink head 22D. The second ink head 22B is disposed on the opposite side of the light irradiation device 30 side (here, to the right) from the first ink head 22A in the scanning direction Y. The third ink head 22C is disposed on the opposite side of the light irradiation device 30 side from the second ink head 22B in the scanning direction Y. The fourth ink head 22D is disposed on the opposite side of the light irradiation device 30 side from the third ink head 22C in the scanning direction Y. In the following description, when describing all of the ink heads from the first ink head 22A to the fourth ink head 22D, the term "ink head 22" is used as appropriate.

[0022] In this embodiment, as shown in FIG. 4, each of the first ink head 22A to the fourth ink head 22D has a nozzle surface 23. The nozzle surface 23 forms the bottom surface of the ink head 22. The nozzle surface 23 is exposed downward from the carriage 20. A plurality of nozzles 24 are formed in one nozzle surface 23. In this embodiment, the plurality of nozzles 24 in one nozzle surface 23 are arranged side by side in the transport direction X. Here, a row of the plurality of nozzles 24 arranged side by side in the transport direction X is referred to as a nozzle row 25. In this embodiment, the number of nozzle rows 25 in one nozzle surface 23 is two. However, the number of nozzle rows 25 in one nozzle surface 23 may be one, or three or more.

[0023] In this embodiment, ink of a different color is ejected from the nozzles 24 for each nozzle row 25 of the ink head 22. The ink ejected from the nozzles 24 is, for example, a process color ink or a special color ink. Process color inks include, for example, cyan ink, magenta ink, yellow ink, and black ink. Special color inks include, for example, white ink, clear ink, gloss ink, primer ink, fluorescent ink, metallic ink, orange ink, red ink, violet ink, blue ink, and green ink.

[0024] The ink ejected from the nozzles 24 of the ink head 22 is a photocurable ink, the drying of which is accelerated when irradiated with light. The light is, for example, ultraviolet light, and in this example, the ink is an ultraviolet curable ink, the hardening of which is accelerated when irradiated with ultraviolet light.

[0025] In this embodiment, the ink ejected from the ink head 22 is contained in an ink cartridge 26 shown in Fig. 2. The ink cartridge 26 is disposed, for example, in the internal space of the case 11. For example, one ink cartridge 26 is connected to one ink head 22. The ink cartridge 26 is connected to the ink head 22 via, for example, a tube (not shown), and the ink contained in the ink cartridge 26 is supplied to the ink head 22 through the tube.

[0026] The light irradiation device 30 is a device that irradiates light onto the ink ejected from the nozzles 24 of the ink head 22. Here, the light irradiation device 30 is configured to be able to irradiate light onto the ink ejected onto the printing substrate 5 supported by the support table 40. In this embodiment, since the ink ejected from the nozzles 24 is an ultraviolet curable ink, the light irradiation device 30 is an ultraviolet irradiation device that irradiates the ink ejected from the nozzles 24 with ultraviolet light.

[0027] 4, the light irradiation device 30 is provided on the carriage 20 and configured to be movable in the scanning direction Y together with the carriage 20 and the ink head 22. In this embodiment, the light irradiation device 30 is provided on one side of the carriage 20 in the scanning direction Y (here, the left side), and on one side of the ink head 22 in the scanning direction Y. However, the light irradiation device 30 may be provided on the other side of the carriage 20 in the scanning direction Y (here, the right side), and on the other side of the ink head 22 in the scanning direction Y.

[0028] The configuration of the light irradiation device 30 is not particularly limited. In this embodiment, the light irradiation device 30 has an irradiation body 31 (see FIG. 4) and a light source 32 (see FIG. 3). As shown in FIG. 4, the irradiation body 31 is, for example, a rectangular parallelepiped shape and is hollow. An irradiation port 33 is formed on the bottom surface of the irradiation body 31. The shape of the irradiation port 33 is a square shape, but is not particularly limited. The light source 32 emits light (ultraviolet light in this case) and is disposed inside the irradiation body 31. The light emitted from the light source 32 passes through the irradiation port 33 and is irradiated onto the ink ejected onto the printing substrate 5.

[0029] 2, the support table 40 supports the printing substrate 5. Here, the printing substrate 5 is placed on the upper surface of the support table 40. Printing is performed on the printing substrate 5 on the support table 40, and ink is ejected onto the printing substrate 5 supported by the support table 40 and ultraviolet light is irradiated. The upper surface of the support table 40 extends in the scanning direction Y and the transport direction X.

[0030] 1, the printer 10 includes a first movement mechanism 51 that moves the ink head 22 relatively to the support table 40 in the scanning direction Y, and a second movement mechanism 52 that moves the printing substrate 5 supported by the support table 40 relatively to the ink head 22 in the transport direction X. In addition, although a detailed configuration is omitted, the printer 10 includes a lifting mechanism 53 that lifts and lowers the support table 40.

[0031] The first moving mechanism 51 moves the carriage 20, the ink head 22, and the light irradiation device 30 in the scanning direction Y along the guide rail 18. The configuration of the first moving mechanism 51 is not particularly limited. Although not shown, the first moving mechanism 51 has, for example, left and right pulleys, a belt, and a scan motor. The left pulley is provided around the left end of the guide rail 18, and the right pulley is provided around the right end of the guide rail 18. The belt is, for example, an endless belt, and is wound around the left and right pulleys. The carriage 20 is attached and fixed to the belt. The scan motor is connected to one of the left and right pulleys. Here, the pulley rotates when the scan motor is driven, and the belt runs between the left and right pulleys. As a result, the carriage 20, the ink head 22, and the light irradiation device 30 move in the scanning direction Y along the guide rail 18.

[0032] The second moving mechanism 52 moves the support table 40 in the transport direction X, thereby moving the printing material 5 supported by the support table 40 in the transport direction X. The configuration of the second moving mechanism 52 is not particularly limited. Here, the second moving mechanism 52 includes a support table carriage that supports the support table 40, and a pair of left and right slide rails that slidably support the support table carriage and extend in the transport direction X, although not shown. The second moving mechanism 52 further includes a pair of front and rear pulleys provided in front and behind the slide rails, and a belt wound around the pair of front and rear pulleys, although not shown. The support table carriage is fixed to this belt. A feed motor is connected to one of the pair of front and rear pulleys. Here, the feed motor is driven to run the belt, and the support table 40 moves in the transport direction X together with the support table carriage.

[0033] 5 and 6 are front views showing the carriage 20 and the cap unit 60. FIG. 7 is a front view showing the carriage 20 and the wiper unit 70. The printer 10 includes a cap unit 60 (see FIG. 5) and a wiper unit 70 (see FIG. 7). The cap unit 60 is disposed, for example, to the left or right of the support base 40. As shown in FIG. 5, the cap unit 60 includes a cap 61, a capping mechanism 62, and a suction pump 63. The cap 61 is configured to be attachable to the ink head 22 so as to cover the multiple nozzles 24 (see FIG. 4) of the ink head 22. The number of ink heads 22 to which one cap 61 is attached is one. Therefore, the number of caps 61 is four, which is the same as the number of ink heads 22. However, the number of ink heads 22 to which one cap 61 is attached may be more than one (for example, all four).

[0034] The capping mechanism 62 is a mechanism that raises and lowers the cap 61 to attach the cap 61 to and separate it from the ink head 22. For example, the capping mechanism 62 is configured to attach the cap 61 to the ink head 22 by raising the cap 61 as shown in Fig. 6, and to separate the cap 61 from the ink head 22 by lowering the cap 61 as shown in Fig. 5.

[0035] The configuration of the capping mechanism 62 is not particularly limited. Here, the capping mechanism 62 has a support member 65 and a lifting motor 67. The support member 65 is, for example, a plate-shaped member, and supports the four caps 61. The lifting motor 67 is connected to the support member 65. Here, the support member 65 is lifted and lowered by being driven by the lifting motor 67. As the support member 65 is lifted and lowered, the four caps 61 are lifted and lowered at the same time.

[0036] As shown in FIG. 5, the suction pump 63 is connected to the cap 61. Here, one suction pump 63 is connected to one cap 61. Therefore, the number of suction pumps 63 is four, which is the same as the number of caps 61. The suction pump 63 sucks ink in the connected cap 61 and ink in the ink head 22 attached to the cap 61. The suction pump 63 is provided in the middle of a tube 64. One end of the tube 64 is connected to the cap 61, and the other end of the tube 64 is connected to a waste liquid tank (not shown). There is, for example, one waste liquid tank, which is connected to four caps 61 via four tubes 64. For example, when the suction pump 63 is driven with the cap 61 attached to the ink head 22, ink is sucked out from the nozzle 24 (see FIG. 4) and discharged into the cap 61. The ink in the cap 61 sucked by the suction pump 63 is discharged into the waste liquid tank via the tube 64.

[0037] In this embodiment, the four suction pumps 63 can be driven independently. For example, it is possible to drive one of the four suction pumps 63 and not drive the remaining three suction pumps 63.

[0038] The wiper unit 70 shown in Fig. 7 is disposed near the cap unit 60 shown in Fig. 5, and is provided below the ink head 22. The wiper unit 70 wipes the nozzle surface 23 of the ink head 22. The wiper unit 70 includes a wiper 71, a wiping mechanism 72, and a cleaning liquid tank 73 in which cleaning liquid is stored.

[0039] The wiper 71 is a member that wipes the nozzle surface 23. The wiper 71 is a flat plate-shaped member that extends back and forth and up and down. The wiper 71 is made of, for example, rubber. In this embodiment, one wiper 71 is configured to be able to wipe the nozzle surfaces 23 of all of the ink heads 22 in sequence. However, for example, multiple wipers 71 (four in this case) may be provided, and one wiper 71 may be configured to wipe the nozzle surface 23 of one ink head 22.

[0040] The wiping mechanism 72 is a mechanism for wiping the nozzle surface 23 with the wiper 71. The wiping mechanism 72 performs wiping by moving the wiper 71 and the ink head 22 relatively. In this embodiment, the wiping mechanism 72 is configured to move the wiper 71 in a state in which the wiper 71 is in contact with the nozzle surface 23. However, the wiping mechanism 72 may perform wiping by moving the ink head 22 in a state in which the wiper 71 is in contact with the nozzle surface 23, or may perform wiping by moving both the wiper 71 and the ink head 22.

[0041] The configuration of the wiping mechanism 72 is not particularly limited. Here, the wiping mechanism 72 has a rotating shaft 75 and a rotating motor 76. The rotating shaft 75 extends forward and backward, and is connected to one end of the wiper 71. The rotating motor 76 is connected to the rotating shaft 75. The wiper 71 can rotate around the rotating shaft 75 by driving the rotating motor 76. When the wiper 71 is arranged in a rotation position such that the end farther from the rotating shaft 75 is on top, the end is arranged at a position slightly higher than the nozzle surface 23. In this state, the ink head 22 is moved in the scanning direction Y, whereby the nozzle surface 23 is wiped by the wiper 71. On the other hand, when the wiper 71 is arranged in a rotation position such that the end farther from the rotating shaft 75 is on the bottom, the wiper 71 is immersed in the cleaning liquid in the cleaning liquid tank 73 installed below the rotating shaft 75.

[0042] As shown in FIG. 2, the printer 10 includes a control device 90. The control device 90 executes processes related to printing and a cleaning process P1 (see FIG. 8) described later. The configuration of the control device 90 is not particularly limited. The control device 90 is, for example, a microcomputer. The control device 90 includes, for example, an I / F, a CPU, a ROM, and a RAM. The control device 90 is provided inside the case 11. However, the control device 90 may be realized by a computer or the like installed outside the case 11. In this case, the control device 90 is connected to a control board (not shown) of the printer 10 so as to be able to communicate with it via wire or wirelessly.

[0043] 3, the control device 90 is communicatively connected to the ink head 22, the light irradiation device 30 (more specifically, the light source 32), the first moving mechanism 51, the second moving mechanism 52, the lifting mechanism 53, the cap unit 60 (more specifically, the capping mechanism 62 and the suction pump 63), and the wiper unit 70 (more specifically, the rotation motor 76 of the wiping mechanism 72). The control device 90 controls the ink head 22, the light irradiation device 30, the first moving mechanism 51, the second moving mechanism 52, the lifting mechanism 53, the cap unit 60, and the wiper unit 70.

[0044] Incidentally, in this embodiment, a cleaning process P1 is performed on each ink head 22 before printing starts (for example, immediately before printing starts) or after printing ends (for example, immediately after printing ends). FIG. 8 is a flowchart showing an example of the cleaning process P1. As shown in FIG. 8, the cleaning process P1 includes at least one of a suction process P11 and a wiping process P13. Here, the cleaning process P1 includes an idle suction process P12 and a flushing process P14 in addition to the suction process P11 and the wiping process P13. In the cleaning process P1 in this embodiment, the suction process P11, the idle suction process P12, the wiping process P13, and the flushing process P14 are performed in this order. Note that in the cleaning process P1, an attachment process of attaching a cleaning liquid to the wiper 71 may be performed before the wiping process P13.

[0045] The suction process P11, as shown in FIG. 6, is a process of suctioning ink from the nozzles 24 (see FIG. 4) with the cap 61 attached to the ink head 22. In the suction process P11, first, the cap 61 is attached to the ink head 22 so that the nozzles 24 are covered with the cap 61. Then, the suction pump 63 is driven. This causes the ink in the ink head 22 to be ejected (in other words, sucked up) from the nozzles 24. The ink ejected from the nozzles 24 is discharged into the cap 61. By driving the suction pump 63, the ink in the cap 61 is discharged through the tube 64 to a waste liquid tank.

[0046] The idle suction process P12 shown in Fig. 8 is a process in which the suction pump 63 is driven in a state in which the cap 61 is separated from the ink head 22. In the idle suction process P12, after the suction process P11, as shown in Fig. 5, the capping mechanism 62 is controlled so as to separate the cap 61 attached to the ink head 22 from the ink head 22. As a result, the cap 61 is lowered and positioned below the ink head 22. In this state, the suction pump 63 is driven. As a result, the ink in the ink head 22 is not sucked, but the ink in the cap 61 is sucked and discharged into the waste liquid tank through the tube 64.

[0047] The wiping process P13 shown in Fig. 8 is a process of wiping the nozzle surface 23 with the wiper 71. In the wiping process P13, after the idle suction process P12, the wiping mechanism 72 is controlled so that the end of the wiper 71 farther from the rotation shaft 75 faces up, as shown in Fig. 7. Thereafter, the ink head 22 is moved in the scanning direction Y by the first moving mechanism 51 shown in Fig. 1, and the wiper 71 moves relatively while in contact with the nozzle surface 23, whereby the nozzle surface 23 is wiped by the wiper 71.

[0048] 8 is a process for ejecting ink from inside the ink head 22 into the cap 61. Here, in the flushing process P14, the suction pump 63 is not driven, and the ink head 22 is controlled to eject ink from the nozzles 24. In the flushing process P14, after the wiping process P13, the cap 61 is moved below the ink head 22, and the nozzle surface 23 and the cap 61 are separated from each other. Then, the suction pump 63 is driven to perform idle suction, while the ink head 22 is controlled to eject ink from the nozzles 24 toward the cap 61.

[0049] The cleaning process P1 is a process that is periodically performed to suppress ink ejection defects in the nozzles 24 and ensure print quality. For example, when ink is ejected from the nozzles 24, the ink may adhere to the nozzle surface 23 of the ink head 22. The ink that adheres to the nozzle surface 23 may harden and become highly viscous ink. If the ink becomes highly viscous, the nozzles 24 may become clogged, which may result in ink ejection defects. Since this ink ejection defect may affect print quality, the cleaning process P1 is periodically performed to remove the viscous ink.

[0050] However, the cleaning process P1 takes time, and ink is consumed by performing the suction process P11 and the flushing process P14. Therefore, it is preferable to reduce the number of times the cleaning process P1 is performed while removing the thickened ink from the nozzle surface 23.

[0051] In this embodiment, among the multiple ink heads 22, there are ink heads 22 in which the ink adhering to the nozzle surface 23 tends to harden, i.e., tends to thicken, and ink heads 22 in which the ink adhering to the nozzle surface 23 tends not to harden, i.e., tends not to thicken. Conventionally, the cleaning process P1 was performed on all four ink heads 22 at once when the ink ejected from the ink head 22 in which the ink tends to thicken tends to thicken (in other words, harden) on the nozzle surface 23. Therefore, the cleaning process P1 was sometimes performed on the ink head 22 in which the ink tends not to thicken, even when the ink had not yet thickened. As a result, the amount of ink consumed by the cleaning process P1 could increase.

[0052] Therefore, in this embodiment, the timing of the cleaning process P1 is adjusted for each ink head 22, so as to reduce unnecessary cleaning processes P1 as much as possible.

[0053] 3, in order to execute the cleaning process P1 according to this embodiment, the control device 90 includes a storage unit 91, a determination unit 93, an acquisition unit 95, a judgment unit 97, and a cleaning execution unit 99. Each of the units 91 to 99 of the control device 90 may be configured by software or by hardware. For example, each of the units 91 to 99 of the control device 90 may be executed by one or a plurality of processors, or may be incorporated into a circuit.

[0054] Next, the control up to the execution of the cleaning process P1 will be described. Fig. 9 is a diagram showing the distance from the light irradiation device 30, the amount of irradiation light A2, the degree of ink viscosity A1, and the cleaning interval T1 in each ink head 22 in this embodiment. Note that in Fig. 9 and other figures, for the amount of irradiation light A2, the more "x" there are, the greater the amount of irradiation light A2 is, and the fewer "x" there are, the smaller the amount of irradiation light A2 is. Also, for the degree of ink viscosity A1, the more "x" there are, the higher the degree of ink viscosity A1 is, and the fewer "x" there are, the lower the degree of ink viscosity A1 is.

[0055] First, the determination unit 93 in Fig. 3 determines a cleaning interval T1 for each of the first ink head 22A to the fourth ink head 22D as shown in Fig. 9. Here, the cleaning interval T1 refers to an interval that can be opened from the time when the previous cleaning process P1 was performed, when performing the cleaning process P1 for each ink head 22.

[0056] In this embodiment, the cleaning interval T1 is determined according to the degree of viscosity A1 of the ink adhering to the nozzle surface 23 of each ink head 22. For example, for an ink head 22 in which the degree of viscosity A1 of the ink adhering to the nozzle surface 23 is high, i.e., the ink is prone to thickening, the cleaning interval T1 is determined to be short. On the other hand, for an ink head 22 in which the degree of viscosity A1 of the ink adhering to the nozzle surface 23 is low, i.e., the ink is unlikely to thicken, the cleaning interval T1 is determined to be long.

[0057] In this embodiment, as shown in FIG. 9, the degree of viscosity increase A1 of the ink attached to the nozzle surface 23 is estimated according to the amount of irradiation light A2 irradiated from the light irradiation device 30 to the nozzle surface 23 of the ink head 22. The amount of irradiation light A2 is, for example, the amount of irradiation light A2 per unit time. Here, the light emitted from the light irradiation device 30 is reflected by the support base 40 and the printing substrate 5 supported by the support base 40, and is irradiated to the nozzle surface 23 as reflected light. The amount of irradiation light A2 can also be said to be the amount of light due to the reflected light. The determination unit 93 in FIG. 3 determines the cleaning interval T1 according to the amount of irradiation light A2 irradiated from the light irradiation device 30 to the nozzle surface 23 of the ink head 22. Here, the cleaning interval T1 is determined to be short for the ink head 22 with a large amount of irradiation light A2. On the other hand, the cleaning interval T1 is determined to be long for the ink head 22 with a small amount of irradiation light A2.

[0058] In this embodiment, the amount of irradiation light A2 irradiated onto the nozzle surface 23 of each ink head 22 is determined according to the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22. Here, as shown in Fig. 4, the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22 refers to, for example, the distance in the scanning direction Y from the center C11 of the light irradiation device 30 in the scanning direction Y to the center of the ink head 22 in the scanning direction Y.

[0059] In this embodiment, the distance D11 from the light irradiation device 30 to the first ink head 22A is the distance in the scanning direction Y from the center C11 of the light irradiation device 30 to the center C21 in the scanning direction Y of the first ink head 22A. Similarly, the distance D12 from the light irradiation device 30 to the second ink head 22B is the distance in the scanning direction Y from the center C11 of the light irradiation device 30 to the center C22 in the scanning direction Y of the second ink head 22B. The distance D13 from the light irradiation device 30 to the third ink head 22C is the distance in the scanning direction Y from the center C11 of the light irradiation device 30 to the center C23 in the scanning direction Y of the third ink head 22C. In addition, the distance D14 from the light irradiation device 30 to the fourth ink head 22D is the distance in the scanning direction Y from the center C11 of the light irradiation device 30 to the center C24 in the scanning direction Y of the fourth ink head 22D.

[0060] 9, the longer the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22, the smaller the amount of irradiated light A2, and the shorter the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22, the larger the amount of irradiated light A2. In this embodiment, the distances D11, D12, D13, and D14 in the scanning direction Y from the light irradiation device 30 are longer in the order of the first ink head 22A, the second ink head 22B, the third ink head 22C, and the fourth ink head 22D. Therefore, the amount of irradiated light A2 decreases and the degree of viscosity increase A1 decreases in the order of the first ink head 22A, the second ink head 22B, the third ink head 22C, and the fourth ink head 22D.

[0061] The determination unit 93 in FIG. 3 determines the cleaning interval T1 according to the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22. The determination unit 93 sets the cleaning interval T1 to a shorter time as the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22 is shorter, and sets the cleaning interval T1 to a longer time as the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22 is longer. Here, the determination unit 93 determines the cleaning interval T1 for the first ink head 22A to be the first interval T11, and determines the cleaning interval T1 for the second ink head 22B to be the second interval T12. In addition, the determination unit 93 determines the cleaning interval T1 for the third ink head 22C to be the third interval T13, and determines the cleaning interval T1 for the fourth ink head 22D to be the fourth interval T14. Here, the first interval T11 is smaller than the second interval T12 to the fourth interval T14. The second interval T12 is larger than the first interval T11 and smaller than the third interval T13 and the fourth interval T14.

[0062] In this embodiment, the third interval T13 and the fourth interval T14 are the same time. This is because when the amount of irradiated light A2 is relatively small (for example, when it is smaller than a predetermined reference amount of light), it is considered that the print quality is unlikely to be affected even if there is no difference in the cleaning interval T1. Of course, here, the third ink head 22C is closer to the light irradiation device 30 in the scanning direction Y than the fourth ink head 22D, so the third interval T13 may be a time shorter than the fourth interval T14.

[0063] Note that the specific values ​​of the first interval T11 to the fourth interval T14 are not particularly limited. The first interval T11 is, for example, 15 minutes. The second interval T12 is, for example, 30 minutes. The third interval T13 and the fourth interval T14 are, for example, 60 minutes. In this embodiment, the first interval T11 to the fourth interval T14 determined by the determination unit 93 are stored in the storage unit 91 of FIG. 3.

[0064] In this way, after the cleaning interval T1 for each ink head 22 is determined by the determination unit 93 in Fig. 3, control is performed up to the execution of the cleaning process P1 in accordance with the procedure shown in the flowchart in Fig. 10. The cleaning process P1 in this embodiment is a process that is executed before printing starts or after printing ends. Therefore, each step in Fig. 10 is executed before printing starts or after printing ends.

[0065] Here, first, in step S1 in Fig. 10, the acquisition unit 95 in Fig. 3 acquires the accumulated printing time T2 for each ink head 22. Here, the accumulated printing time T2 refers to the total printing time for each ink head 22 from the previous cleaning process P1. The printing time refers to the time required to print on the printing substrate 5 based on the image data for printing. The accumulated printing time T2 is obtained by counting the time required to print on the printing substrate 5. The accumulated printing time T2 does not include the time required for the cleaning process P1 or the waiting time between prints.

[0066] The accumulated printing time T2 is reset when the cleaning process P1 is performed on the ink head 22. Here, the timing at which the cleaning process P1 is performed may differ for each ink head 22. Therefore, the accumulated printing time T2 is set for each ink head 22. The accumulated printing time T2 for each ink head 22 acquired by the acquisition unit 95 is stored in the memory unit 91 in FIG. 3.

[0067] After acquiring the accumulated printing time T2 for each ink head 22, in step S2 of Fig. 10, the determination unit 97 of Fig. 3 determines whether or not to execute the cleaning process P1 for each ink head 22. The determination unit 97 determines, for each ink head 22, whether or not the accumulated printing time T2 is equal to or longer than the cleaning interval T1.

[0068] The determination unit 97 determines, for example, whether the accumulated printing time T2 of the first ink head 22A is the first interval T11 (see FIG. 9), which is the cleaning interval T1 of the first ink head 22A. If the determination unit 97 determines that the accumulated printing time T2 of the first ink head 22A is less than the first interval T11, the ink attached to the nozzle surface 23 of the first ink head 22A has not thickened and is not cured. In this case, since it is not necessary to perform the cleaning process P1 on the first ink head 22A, the determination in step S2 in FIG. 10 is NO, and the flowchart in FIG. 10 is terminated.

[0069] On the other hand, if the determination unit 97 determines in step S2 of Fig. 10 that the accumulated printing time T2 of the first ink head 22A is equal to or longer than the first interval T11, the ink attached to the nozzle surface 23 of the first ink head 22A has thickened and is in a state where the ink is cured. Therefore, it is better to perform a cleaning process P1 to remove the thickened ink. In this case, the determination in step S2 of Fig. 10 is YES, and the process proceeds to step S3.

[0070] In step S3, the cleaning execution unit 99 in Fig. 3 executes a cleaning process P1 on the first ink head 22A. Here, the cleaning execution unit 99 executes the cleaning process P1 by sequentially executing a suction process P11, an idle suction process P12, a wiping process P13, and a flushing process P14 shown in Fig. 8 on the first ink head 22A.

[0071] Although the above description is directed to the first ink head 22A, the steps in FIG. 10 are performed for the second ink head 22B, the third ink head 22C, and the fourth ink head 22D before printing starts or after printing ends. That is, the determination unit 97 performs determination (step S2) for the second ink head 22B, the third ink head 22C, and the fourth ink head 22D, and a cleaning process P1 is performed in step S3 for the ink heads 22 whose accumulated printing time T2 is determined by the determination unit 97 to be equal to or longer than the cleaning interval T1 (e.g., the second interval T12 to the fourth interval T14). After the cleaning process P1 is performed, the accumulated printing time T2 for the ink heads 22 for which the cleaning process P1 has been performed is reset to 0.

[0072] As described above, in this embodiment, as shown in FIG. 2, the printer 10 includes the ink head 22, the cap unit 60 (see FIG. 5), the wiper unit 70 (see FIG. 7), and the control device 90. As shown in FIG. 4, the ink head 22 has a nozzle surface 23 in which the nozzles 24 for ejecting ink are formed. As shown in FIG. 5 and FIG. 6, the cap unit 60 includes a cap 61 that is attached to the ink head 22 so as to cover the nozzles 24, a capping mechanism 62 that attaches the cap 61 to the ink head 22 or separates it from the ink head 22, and a suction pump 63 connected to the cap 61. As shown in FIG. 7, the wiper unit 70 includes a wiper 71 that wipes the nozzle surface 23, and a wiping mechanism 72 that moves the wiper 71 or the ink head 22 while the wiper 71 is in contact with the nozzle surface 23. Here, as shown in FIG. 8, a cleaning process P1 is a process of performing at least one of a suction process P11 in which ink is discharged from the nozzles 24 with the cap 61 attached to the ink head 22, and a wiping process P13 in which the wiper 71 wipes the nozzle surface 23. As shown in FIG. 3, the control device 90 includes a determination unit 93, an acquisition unit 95, a judgment unit 97, and a cleaning execution unit 99. The determination unit 93 determines a cleaning interval T1 (see FIG. 9) for each ink head 22 according to the degree of viscosity increase A1 (see FIG. 9) of the ink attached to the nozzle surface 23. The acquisition unit 95 acquires a cumulative printing time T2 of the ink head 22 from the previous cleaning process P1. The judgment unit 97 judges whether the cumulative printing time T2 is equal to or greater than the cleaning interval T1. The cleaning execution unit 99 executes the cleaning process P1 for the ink head 22 for which the judgment unit 97 judges that the cumulative printing time T2 is equal to or greater than the cleaning interval T1.

[0073] 8 is preferably performed on an ink head 22 in which the ink adhering to the nozzle surface 23 has become viscous. In this embodiment, the timing for performing the cleaning process P1 on the ink head 22 is determined by a cleaning interval T1 for each ink head 22 determined according to the degree of viscosity A1 of the ink adhering to the nozzle surface 23. Therefore, the cleaning process P1 can be performed for each ink head 22 at the timing when the ink adhering to the nozzle surface 23 becomes viscous. Therefore, since the cleaning process P1 is performed for each ink head 22 at an appropriate timing when the ink becomes viscous, it is possible to reduce the execution of unnecessary cleaning processes P1 on the ink heads 22, and to reduce the amount of ink consumed by the cleaning process P1.

[0074] In this embodiment, as shown in FIG. 4, the printer 10 includes a light irradiation device 30 that irradiates light onto the ink discharged from the ink head 22. The determination unit 93 in FIG. 3 determines the cleaning interval T1 according to the amount of irradiation light A2 (see FIG. 9) irradiated from the light irradiation device 30 onto the nozzle surface 23 of the ink head 22. In this embodiment, the degree of viscosity increase A1 of the ink attached to the nozzle surface 23 can be estimated based on the amount of irradiation light A2 from the light irradiation device 30. As shown in FIG. 9, for example, when the amount of irradiation light A2 per unit time is large, the ink is likely to thicken, and when the amount of irradiation light A2 per unit time is small, the ink is unlikely to thicken. Therefore, by determining the cleaning interval T1 according to the amount of irradiation light A2 irradiated onto the nozzle surface 23, the cleaning process P1 can be performed at an appropriate timing when the ink has thickened.

[0075] In this embodiment, as shown in FIG. 4, the light irradiation device 30 is arranged next to the ink head 22 in the scanning direction Y. The determination unit 93 in FIG. 3 determines the cleaning interval T1 according to the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22 (for example, in the case of the first ink head 22A, the distance D11 (see FIG. 9)). Here, as shown in FIG. 9, the degree of viscosity increase A1 of the ink attached to the nozzle surface 23 can be estimated based on the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22. For example, when the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22 is short (for example, in the case of the distance D11 of the first ink head 22A), the ink is likely to thicken, and when the distance is long (for example, in the case of the distance D14 of the fourth ink head 22D), the ink is unlikely to thicken. Therefore, by determining the cleaning interval T1 according to the distance in the scanning direction Y from the light irradiation device 30 to the ink head 22, the cleaning process P1 can be performed at an appropriate timing when the ink has thickened.

[0076] In this embodiment, as shown in FIG. 4, the ink head 22 has a first ink head 22A and a second ink head 22B arranged on the opposite side of the first ink head 22A to the light irradiation device 30 in the scanning direction Y. As shown in FIG. 9, the determination unit 93 in FIG. 3 determines the cleaning interval T1 of the first ink head 22A to be the first interval T11, and determines the cleaning interval T1 of the second ink head 22B to be the second interval T12 larger than the first interval T11. This allows the cleaning interval T1 to be set to a short time (first interval T11) for the first ink head 22A that is arranged relatively close to the light irradiation device 30 and has a large amount of irradiation light A2. On the other hand, the cleaning interval T1 can be set to a long time (second interval T12) for the second ink head 22B that is arranged farther from the light irradiation device 30 than the first ink head 22A and has a small amount of irradiation light A2. Therefore, a different cleaning interval T1 can be set for each ink head 22.

[0077] 3 executes the cleaning process P1 when the determining unit 97 determines that the accumulated printing time T2 is equal to or greater than the cleaning interval T1 before printing starts or after printing ends. This allows the cleaning process P1 to be executed not only when the accumulated printing time T2 is equal to or greater than the cleaning interval T1, but also before printing starts or after printing ends, depending on the degree of ink viscosity. Therefore, by executing the cleaning process P1, printing can be performed with the viscosity of the ink attached to the nozzle surface 23 suppressed, making it easier to ensure print quality.

[0078] <Second embodiment> Next, a printer 110 according to the second embodiment will be described. Fig. 11 is a bottom view showing the carriage 20, ink head 22, and light irradiation device 130 according to the second embodiment. Fig. 12 is a diagram showing the color of ink ejected from each ink head 22, the minimum distance from the light irradiation device 130, the amount of irradiated light A2, the degree of ink viscosity A1, and the cleaning interval T1 in the second embodiment.

[0079] In this embodiment, as shown in Fig. 11, the printer 110 includes a light irradiation device 130. In the first embodiment, the number of the light irradiation device 30 is one (see Fig. 4), but the number of the light irradiation devices 130 according to this embodiment is two. Here, of the two light irradiation devices 130, one light irradiation device 130 is referred to as a first light irradiation device 130A, and the other light irradiation device 130 is referred to as a second light irradiation device 130B.

[0080] In this embodiment, the two light irradiation devices 130 are arranged to sandwich the first ink head 22A to the fourth ink head 22D in the scanning direction Y. The first light irradiation device 130A is provided on one side (here, the left side) of the multiple ink heads 22 in the scanning direction Y. The first light irradiation device 130A is provided on the left side of the carriage 20. The second light irradiation device 130B is provided on the other side (here, the right side) of the multiple ink heads 22 in the scanning direction Y. The second light irradiation device 130B is provided on the right side of the carriage 20. In this embodiment, from left to right, the first light irradiation device 130A, the first ink head 22A, the second ink head 22B, the third ink head 22C, the fourth ink head 22D, and the second light irradiation device 130B are arranged in the scanning direction Y in this order.

[0081] In this embodiment, the first ink head 22A and the fourth ink head 22D eject special color inks. The second ink head 22B and the third ink head 22C eject process color inks. In detail, as shown in FIG. 11, the first ink head 22A ejects gloss ink from the nozzles 24 of one of the two nozzle rows 25, and the other ejects primer ink from the nozzles 24 of the other nozzle row 25. The second ink head 22B ejects cyan ink from the nozzles 24 of one of the two nozzle rows 25, and the other ejects magenta ink from the nozzles 24 of the other nozzle row 25. The third ink head 22C ejects yellow ink from the nozzles 24 of one of the two nozzle rows 25, and the other ejects black ink from the nozzles 24 of the other nozzle row 25. The fourth ink head 22A ejects white ink from the nozzles 24 of the two nozzle rows 25.

[0082] Here, the ease with which the ink thickens varies depending on the color of the ink. Here, the ease with which the ink thickens refers to, for example, the ease with which the ink hardens due to light irradiation (in other words, the degree of hardening), and the ease with which water-based ink, solvent ink, and the like dry. For example, the gloss ink and primer ink ejected from the first ink head 22A thicken more easily than the white ink ejected from the fourth ink head 22D. That is, the gloss ink and primer ink harden more easily than the white ink. Here, the gloss ink and primer ink thicken more easily than the process color ink, and the process color ink thickens more easily than the white ink. In this embodiment, the gloss ink and primer ink are an example of a first ink. The white ink is an example of a second ink that is less likely to thicken than the first ink.

[0083] When the light irradiation device 130 includes two devices, the first light irradiation device 130A and the second light irradiation device 130B, as in this embodiment, the distance in the scanning direction Y from the first light irradiation device 130A to the ink head 22 may differ from the distance in the scanning direction Y from the second light irradiation device 130B to the ink head 22. Here, the distance in the scanning direction Y from the first light irradiation device 130A to the ink head 22 is referred to as the first distance. The distance in the scanning direction Y from the second light irradiation device 130B to the ink head 22 is referred to as the second distance.

[0084] In this embodiment, in the first ink head 22A, the first distance D11 in the scanning direction Y from the center C11 of the first light irradiation device 130A is shorter than the second distance D21 in the scanning direction Y from the center C12 in the scanning direction Y of the second light irradiation device 130B. Similarly, in the second ink head 22B, the first distance D12 in the scanning direction Y from the center C11 of the first light irradiation device 130A is shorter than the second distance D22 in the scanning direction Y from the center C12 of the second light irradiation device 130B. On the other hand, in the third ink head 22C, the first distance D13 in the scanning direction Y from the center C11 of the first light irradiation device 130A is longer than the second distance D23 in the scanning direction Y from the center C12 of the second light irradiation device 130B. Similarly, in the fourth ink head 22D, a first distance D14 in the scanning direction Y from the center C11 of the first light irradiation device 130A is longer than a second distance D24 in the scanning direction Y from the center C12 of the second light irradiation device 130B.

[0085] In this embodiment, the determination unit 93 in FIG. 3 determines the cleaning interval T1 for each ink head 22 according to the minimum distance between the first distance in the scanning direction Y between the first light irradiation device 130A and the ink head 22 and the second distance in the scanning direction Y between the second light irradiation device 130B and the ink head 22. Here, as shown in FIG. 11, the first ink head 22A and the second ink head 22B have a shorter distance in the scanning direction Y for the first light irradiation device 130A than for the second light irradiation device 130B. Therefore, as shown in FIG. 12, the minimum distance for the first ink head 22A and the second ink head 22B is the first distance D11, D12, which is the distance in the scanning direction Y between the first light irradiation device 130A and the ink head 22B.

[0086] 11, for the third ink head 22C and the fourth ink head 22D, the distance in the scanning direction Y from the second light irradiation device 130B is shorter than that from the first light irradiation device 130A. Therefore, as shown in FIG 12, the minimum distance in the third ink head 22C and the fourth ink head 22D is the second distance D23, D24, which is the distance in the scanning direction Y from the second light irradiation device 130B.

[0087] In this embodiment, as shown in FIG. 11, the first distance D11, which is the minimum distance of the first ink head 22A, and the second distance D24, which is the minimum distance of the fourth ink head 22D, are the same. In this case, the determination unit 93 determines the cleaning interval T1 for the ink heads 22A and 22D according to the ease of thickening of the ink discharged from the ink heads 22A and 22D. Here, the gloss ink and primer ink discharged from the first ink head 22A are more likely to thicken and harden than the white ink discharged from the fourth ink head 22D. Therefore, the determination unit 93 determines the cleaning interval T1 for the first ink head 22A to be shorter than that for the fourth ink head 22D. Here, as shown in FIG. 12, the determination unit 93 determines the cleaning interval T1 for the first ink head 22A to be the first interval T11A. Also, the determination unit 93 determines the cleaning interval T1 for the fourth ink head 22D to be the second interval T12A. Here, the second interval T12A is greater than the first interval T11 A. In this embodiment, the first interval T11A is, for example, 15 minutes, and the second interval T12A is, for example, 30 minutes.

[0088] In this embodiment, as shown in Fig. 11, the first distance D12, which is the minimum distance of the second ink head 22B, is the same as the second distance D23, which is the minimum distance of the third ink head 22C. As shown in Fig. 12, the ink ejected from the second ink head 22B and the ink ejected from the third ink head 22C are both process color inks, and have the same tendency to thicken. In this case, the determination unit 93 determines the cleaning interval T1 for the second ink head 22B to be the same as the cleaning interval T1 for the third ink head 22C.

[0089] Here, the first distance D12, which is the minimum distance of the second ink head 22B, and the second distance D23, which is the minimum distance of the third ink head 22C, are longer than the first distance D11, which is the minimum distance of the first ink head 22A, and longer than the second distance D24, which is the minimum distance of the fourth ink head 22D. Therefore, the cleaning interval T1 for the second ink head 22B and the third ink head 22C is determined to be a time longer than the cleaning interval T1 for the first ink head 22A and the fourth ink head 22D. For example, the cleaning interval T1 for the second ink head 22B and the third ink head 22C is set to the third interval T13A. The third interval T13A is longer than the first interval T11A and longer than the second interval T12A. The third interval T13A is, for example, 60 minutes.

[0090] 11, even when the light irradiation device 130 is composed of two devices, a first light irradiation device 130A and a second light irradiation device 130B, the cleaning interval T1 for the ink head 22 is determined according to the distance in the scanning direction Y between the light irradiation device 130 and the ink head 22, whichever of the first and second light irradiation devices 130A and 130B has the shorter distance in the scanning direction Y. In this way, as shown in FIG. 12, the cleaning interval T1 can be set to a short time (here, the first interval T11A) for the first ink head 22A having a large amount of irradiation light A2, and the cleaning interval T1 can be set to a long time (here, the third interval T13A) for the second and third ink heads 22B and 22C having a small amount of irradiation light A2.

[0091] In this embodiment, the determination unit 93 in Fig. 3 determines the cleaning interval T1 for each ink head 22 depending on how easily the ink ejected from the ink head 22 thickens. Here, the degree of viscosity A1 of the ink attached to the nozzle surface 23 can be estimated based on how easily the ink thickens, in other words, how easily it hardens. For example, if the ink is easy to thicken, the degree of viscosity A1 of the ink is likely to become high, and if the ink is not easy to thicken, the degree of viscosity A1 of the ink is not likely to become high. Therefore, by determining the cleaning interval T1 depending on how easily the ink ejected from the ink head 22 thickens, the cleaning process P1 can be performed at an appropriate timing when the ink thickens.

[0092] In this embodiment, as shown in FIG. 12, the first ink head 22A ejects gloss ink and primer ink. The fourth ink head 22D ejects white ink, which is less likely to thicken than the gloss ink and primer ink. The determination unit 93 in FIG. 3 determines the cleaning interval T1 for the first ink head 22A to be the first interval T11A, and determines the cleaning interval T1 for the fourth ink head 22D to be the second interval T12A, which is greater than the first interval T11A. This allows the cleaning interval T1 to be set to a short time for the first ink head 22A, which ejects gloss ink and primer ink, which are easy to harden. On the other hand, the cleaning interval T1 can be set to a long time for the fourth ink head 22D, which ejects white ink, which is less likely to harden than the first ink head 22A.

[0093] <Third embodiment> Next, a printer 210 according to a third embodiment will be described. Fig. 13 is a front view showing the carriage 20, ink head 22, light irradiation device 30, and wiper 271 of a wiper unit 270 according to the third embodiment. Fig. 14 is a diagram showing the distance from the light irradiation device 30 to each ink head 22, the amount of irradiated light A2, the degree of ink viscosity A1, and the cleaning interval T1 in the third embodiment.

[0094] 13, the printer 210 includes a wiper unit 270. The wiper unit 270 includes a wiper 271 and a wiping mechanism 72.

[0095] The wiper 271 is a plate-like member extending in the scanning direction Y and in the vertical direction. The length of the wiper 271 in the scanning direction Y is equal to or greater than the distance from the left end of the left ink head 22 to the right end of the right ink head 22 of two adjacent ink heads 22. Therefore, the wiper 271 can wipe the nozzle surfaces 23 of the two ink heads 22 at once.

[0096] Here, the wiper 271 can wipe the nozzle surface 23 of the first ink head 22A and the nozzle surface 23 of the second ink head 22B at the same time, and can wipe the nozzle surface 23 of the third ink head 22C and the nozzle surface 23 of the fourth ink head 22D at the same time. The wiper 271 moves in the transport direction X while in contact with the nozzle surface 23, for example, from one side to the other in the transport direction X (here, from front to back), thereby wiping the nozzle surface 23. Here, "wiping at the same time" means that the wiper 271 wipes the nozzle surfaces 23 simultaneously while moving from one side to the other in the transport direction X.

[0097] In addition, the configuration of the wiper 271 is not particularly limited as long as it can wipe the nozzle surfaces 23 of the two ink heads 22 at once. In FIG. 13, the wiper 271 is configured with one member, but the wiper 271 may have, for example, multiple members. The wiper 271 may include, for example, a first wiper member and a second wiper member aligned in the scanning direction Y. Here, the first wiper member is disposed to the left of the second wiper member. For example, when wiping the nozzle surfaces 23 of the ink heads 22A and 22B at once, the first wiper member is configured to wipe the nozzle surface 23 of the first ink head 22A, and the second wiper member is configured to wipe the nozzle surface 23 of the second ink head 22B. For example, when wiping the ink heads 22C and 22D at once, the first wiper member is configured to wipe the nozzle surface 23 of the third ink head 22C, and the second wiper member is configured to wipe the nozzle surface 23 of the fourth ink head 22D.

[0098] As shown in Fig. 13, when the wiper 271 is configured to wipe the nozzle faces 23 of multiple ink heads 22 at once, the determination unit 93 in Fig. 3 sets the cleaning interval T1 to be the same for all ink heads 22 that the wiper 271 can wipe at once. When the wiper 271 is configured to wipe the nozzle faces 23 of two adjacent ink heads 22 at once as in this embodiment, the determination unit 93 sets the cleaning interval T1 to be the same for the two adjacent ink heads 22. In this embodiment, the determination unit 93 determines the cleaning interval T1 for the adjacent first and second ink heads 22A and 22B to be the same, and determines the cleaning interval T1 for the adjacent third and fourth ink heads 22C and 22D to be the same, as shown in Fig. 14.

[0099] In this embodiment, the determination unit 93 determines the cleaning interval T1 for the first and second ink heads 22A and 22B to be the first interval T11B. The determination unit 93 also determines the cleaning interval T1 for the third and fourth ink heads 22C and 22D to be the second interval T12B, which is greater than the first interval T11B. The values ​​of the first interval T11B and the second interval T12B may be set to values ​​corresponding to the ink head 22 having the higher degree of viscosity increase A1, i.e., the ink head 22 that is closer to the light irradiation device 30. The first interval T11B is, for example, 15 minutes. The second interval T12B is, for example, 60 minutes.

[0100] As described above, when the wiper 71 is configured to wipe the nozzle faces 23 of multiple ink heads 22 at once as in this embodiment shown in Figure 13, the cleaning interval T1 is determined to be the same for the two ink heads 22A, 22B that are wiped at once. This makes it possible to execute the cleaning process P1 at the same timing for the two ink heads 22A, 22B that are wiped at once.

[0101] In the above embodiments, the cleaning interval T1 is determined for each ink head 22 depending on the distance from the light irradiation device 30, 130. However, for example, a sensor that measures the irradiated light amount A2 of light irradiated to the nozzle surface 23 may be provided for each ink head 22. In this case, the irradiated light amount A2 may be measured by the sensor, and the cleaning interval T1 may be determined depending on the measured irradiated light amount A2.

[0102] In the above-described embodiments, the light irradiation devices 30 and 130 are ultraviolet irradiation devices that irradiate ultraviolet light among other light. However, the light irradiated by the light irradiation devices 30 and 130 is not limited to ultraviolet light. For example, the light irradiation devices 30 and 130 may be infrared irradiation devices that irradiate infrared light. In this case, the ink discharged from the ink head 22 may be so-called aqueous ink. [Explanation of symbols]

[0103] 10 Printers 22 Ink head 22A 1st ink head 22B 2nd ink head 22C 3rd ink head 22D 4th ink head 23 Nozzle surface 24 Nozzles 30 Light irradiation device 60 Cap Units 61 Cap 62 Capping mechanism 63 Suction Pump 70 Wiper unit 71 Wiper 72 Wiping mechanism 90 Control device 93 Decision Section 95 Acquisition Department 97 Judgment section 99 Cleaning Department P1 Cleaning Process T1 Cleaning Interval

Claims

1. A plurality of ink heads each having a nozzle surface on which nozzles for ejecting ink are formed; a light irradiation device that irradiates light onto the ink discharged from the ink head; a wiper unit including a wiper that wipes the nozzle surface and a wiping mechanism that moves the wiper or the ink head while keeping the wiper in contact with the nozzle surface; A control device; Equipped with When the cleaning process is a process of at least performing a wiping process of wiping the nozzle surface with the wiper, The control device includes: a determination unit that determines a cleaning interval for each of the ink heads in accordance with an amount of light irradiated from the light irradiation device to the nozzle surface of the ink head; an acquisition unit that acquires a cumulative printing time of the ink head since the previous cleaning process; a determination unit that determines whether the accumulated printing time is equal to or longer than the cleaning interval; a cleaning execution unit that executes the cleaning process on the ink head for which the cumulative printing time is determined by the determination unit to be equal to or longer than the cleaning interval; A printer equipped with

2. A plurality of ink heads each having a nozzle surface on which nozzles for ejecting ink are formed; a light irradiation device arranged next to the ink head in a scanning direction and configured to irradiate light onto the ink ejected from the ink head; a wiper unit including a wiper that wipes the nozzle surface and a wiping mechanism that moves the wiper or the ink head while keeping the wiper in contact with the nozzle surface; A control device; Equipped with When the cleaning process is a process of at least performing a wiping process of wiping the nozzle surface with the wiper, The control device includes: a determination unit that determines a cleaning interval for each of the ink heads in accordance with a distance from the light irradiation device to the ink heads in the scanning direction; an acquisition unit that acquires a cumulative printing time of the ink head since the previous cleaning process; a determination unit that determines whether the accumulated printing time is equal to or longer than the cleaning interval; a cleaning execution unit that executes the cleaning process on the ink head for which the cumulative printing time is determined by the determination unit to be equal to or longer than the cleaning interval; A printer equipped with

3. The ink head includes: A first ink head; a second ink head disposed on an opposite side of the light irradiation device from the first ink head in the scanning direction; having The printer according to claim 2 , wherein the determination unit determines the cleaning interval for the first ink head to be a first interval, and determines the cleaning interval for the second ink head to be a second interval that is greater than the first interval.

4. The light irradiation device is a first light irradiation device provided on one side of the ink heads in the scanning direction; a second light irradiation device provided on the other side of the plurality of ink heads in the scanning direction; having 4. The printer according to claim 2, wherein the determination unit determines the cleaning interval for each ink head in accordance with the smallest distance between a first distance in the scanning direction between the first light irradiation device and the ink head and a distance in the scanning direction between the second light irradiation device and the ink head.

5. The ink head includes: A first ink head; a second ink head disposed on an opposite side of the first ink head from the light irradiation device in the scanning direction; a third ink head disposed on an opposite side of the second ink head from the light irradiation device in the scanning direction; a fourth ink head disposed on an opposite side of the third ink head from the light irradiation device in the scanning direction; having the wiper unit is configured to wipe the nozzle surface of the first ink head and the nozzle surface of the second ink head with the wiper at one time, and to wipe the nozzle surface of the third ink head and the nozzle surface of the fourth ink head with the wiper at one time, 3. The printer according to claim 2, wherein the determination unit determines the cleaning interval for the first ink head and the second ink head to be a first interval, and determines the cleaning interval for the third ink head and the fourth ink head to be a second interval that is greater than the first interval.

6. A plurality of ink heads each having a nozzle surface on which nozzles for ejecting ink are formed; a light irradiation device that irradiates light onto the ink discharged from the ink head; a wiper unit including a wiper that wipes the nozzle surface and a wiping mechanism that moves the wiper or the ink head while keeping the wiper in contact with the nozzle surface; A control device; Equipped with When the cleaning process is a process of at least performing a wiping process of wiping the nozzle surface with the wiper, The control device includes: a determination unit that determines a cleaning interval for each of the ink heads in accordance with the ease with which the ink discharged from the ink heads is cured by the light irradiated from the light irradiation device; an acquisition unit that acquires a cumulative printing time of the ink head since the previous cleaning process; a determination unit that determines whether the accumulated printing time is equal to or longer than the cleaning interval; a cleaning execution unit that executes the cleaning process on the ink head for which the cumulative printing time is determined by the determination unit to be equal to or longer than the cleaning interval; A printer equipped with

7. The ink head includes: a first ink head that ejects a first ink; a second ink head that ejects a second ink that is less likely to harden than the first ink; having The printer according to claim 6 , wherein the determination unit determines the cleaning interval for the first ink head to be a first interval, and determines the cleaning interval for the second ink head to be a second interval that is greater than the first interval.

8. 8. The printer according to claim 1, wherein the cleaning execution unit executes the cleaning process before printing starts or after printing ends when the determination unit determines that the accumulated printing time is equal to or longer than the cleaning interval.

9. A plurality of ink heads each having a nozzle surface on which nozzles for ejecting ink are formed; a light irradiation device that irradiates light onto the ink discharged from the ink head; a cap unit including a cap attached to the ink head so as to cover the nozzles, a capping mechanism for attaching the cap to and detaching the cap from the ink head, and a suction pump connected to the cap; A control device; Equipped with When the cleaning process is a process of performing at least a suction process of ejecting ink from the nozzles with the cap attached to the ink head, The control device includes: a determination unit that determines a cleaning interval for each of the ink heads in accordance with an amount of light irradiated from the light irradiation device to the nozzle surface of the ink head; an acquisition unit that acquires a cumulative printing time of the ink head since the previous cleaning process; a determination unit that determines whether the accumulated printing time is equal to or longer than the cleaning interval; a cleaning execution unit that executes the cleaning process on the ink head for which the cumulative printing time is determined by the determination unit to be equal to or longer than the cleaning interval; A printer equipped with

10. A plurality of ink heads each having a nozzle surface on which nozzles for ejecting ink are formed; a light irradiation device arranged next to the ink head in a scanning direction and configured to irradiate light onto the ink ejected from the ink head; a cap unit including a cap attached to the ink head so as to cover the nozzles, a capping mechanism for attaching the cap to the ink head and detaching the cap from the ink head, and a suction pump connected to the cap; A control device; Equipped with When the cleaning process is a process of performing at least a suction process of ejecting ink from the nozzles with the cap attached to the ink head, The control device includes: a determination unit that determines a cleaning interval for each of the ink heads in accordance with a distance from the light irradiation device to the ink heads in the scanning direction; an acquisition unit that acquires a cumulative printing time of the ink head since the previous cleaning process; a determination unit that determines whether the accumulated printing time is equal to or longer than the cleaning interval; a cleaning execution unit that executes the cleaning process on the ink head for which the cumulative printing time is determined by the determination unit to be equal to or longer than the cleaning interval; A printer equipped with

11. A plurality of ink heads each having a nozzle surface on which nozzles for ejecting ink are formed; a light irradiation device that irradiates light onto the ink discharged from the ink head; a cap unit including a cap attached to the ink head so as to cover the nozzles, a capping mechanism for attaching the cap to the ink head and detaching the cap from the ink head, and a suction pump connected to the cap; A control device; Equipped with When the cleaning process is a process of performing at least a suction process of ejecting ink from the nozzles with the cap attached to the ink head, The control device includes: a determination unit that determines a cleaning interval for each of the ink heads in accordance with the ease with which the ink ejected from the ink heads is cured by the light irradiated from the light irradiation device; an acquisition unit that acquires a cumulative printing time of the ink head since the previous cleaning process; a determination unit that determines whether the accumulated printing time is equal to or longer than the cleaning interval; a cleaning execution unit that executes the cleaning process on the ink head for which the cumulative printing time is determined by the determination unit to be equal to or longer than the cleaning interval; A printer equipped with

Images