Ink jet printer

Abstract

To provide an ink jet printer capable of suppressing unnecessary light irradiation that does not reach light-curable ink discharged onto a printing object when performing printing on the cylindrical printing object.SOLUTION: A printer includes an ink head 60, a light irradiation device 70, and a control device 100. Nozzles being discharge ports for light-curable ink are formed on the lower surface of the ink head 60. The light irradiation device 70 has four divided illumination regions A1 to A4 in the sub-scanning direction X. Each divided illumination region can be turned on or off individually. The control device includes a discharge control unit that determines the nozzle use range, and a light irradiation control unit that determines the divided illumination region of the light irradiation device 70 to be turned on. The light irradiation control unit turns on the divided illumination region at least a portion of which is at the same position as the nozzle use range determined by the discharge control unit in the sub-scanning direction X.SELECTED DRAWING: Figure 7

Description

Technical Field

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

Background Art

[0002] Conventionally, as shown in Patent Document 1, an inkjet printer that performs printing on a printing target using an ink (photo-curable ink) having a property of curing when irradiated with light is known. The inkjet printer includes a carriage, an ink head, and a light irradiation device. The ink head and the light irradiation device are mounted on the carriage. The carriage is movable in the main scanning direction. A plurality of nozzles are formed on the lower surface of the ink head. The nozzles are ejection ports for the photo-curable ink. The light irradiation device irradiates light onto the printing target. Thereby, the photo-curable ink ejected onto the printing target can be cured.

[0003] Further, Patent Document 1 discloses a rotation mechanism capable of rotating a cylindrical printing target. By alternately repeating the rotation of the printing target by the rotation mechanism and the ejection of the photo-curable ink by the ink head and the irradiation of light by the light irradiation device while moving the carriage in the main scanning direction, printing can be performed on the outer peripheral surface of the printing target.

[0004] When printing on the outer peripheral surface of a cylindrical printing target, the nozzles for ejecting the photo-curable ink may be restricted to only the nozzles within a predetermined range. This is because when viewed along the rotation axis of the printing target, the nozzles are arranged in a straight line, while the outer peripheral surface of the printing target is convexly curved, so the distance between the nozzles and the printing target varies depending on the position of the nozzles. It is known that if the distance between the nozzles and the printing target is large, splashing of the photo-curable ink occurs and the printing quality deteriorates. Therefore, the nozzles with a large distance are restricted from being used.

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Patent Application Laid-Open No. 2014-100880 Summary of the Invention Problems to be Solved by the Invention

[0006] On the other hand, the light irradiation by the light irradiation device is performed under uniform conditions regardless of the range of the nozzles that eject the photocurable ink. However, when the range of the nozzles that eject the photocurable ink changes, the landing range of the photocurable ink on the object to be printed also changes. Therefore, a part of the light irradiated from the light irradiation device may not hit the photocurable ink ejected onto the object to be printed. The light that does not hit the photocurable ink ejected onto the object to be printed is wasted irradiation light that does not contribute to the curing of the photocurable ink. A part of this wasted irradiation light may be reflected by a rotating mechanism or the like and reach the ink head. The reflection of light on the ink head causes an increase in the viscosity of the photocurable ink adhering to the ink head and is one of the factors that cause nozzle clogging.

[0007] The present invention has been made in view of such a point, and an object of the present invention is to provide an inkjet printer that can suppress the irradiation of wasted light that does not hit the photocurable ink ejected onto a cylindrical object to be printed when printing on the object to be printed. Means for Solving the Problems

[0008] The inkjet printer according to the present invention includes an ink head having a lower surface on which nozzles for ejecting photocurable ink onto a three-dimensional object to be printed are formed, and the nozzles are arranged side by side in the sub-scanning direction, a light irradiation device arranged on the side of the ink head and having a plurality of divided lighting areas arranged in the sub-scanning direction, the divided lighting areas being individually lightable or extinguishable, a rotating mechanism for rotating the object to be printed around an axis orthogonal to the sub-scanning direction, and a control device having a light irradiation control unit for individually controlling the lighting and extinguishing of the divided lighting areas.

[0009] Of the light irradiated from the light irradiation device, the light that does not hit the photocurable ink ejected onto the object to be printed is wasteful irradiation light that does not contribute to the curing of the photocurable ink. According to the above configuration, while turning off the divided lighting area that irradiates light that is difficult to hit the photocurable ink ejected onto the object to be printed, only the divided lighting area that irradiates light that is easy to hit the photocurable ink ejected onto the object to be printed can be lit. Thereby, wasteful light irradiation can be suppressed.

Effect of the Invention

[0010] According to the present invention, when printing on a cylindrical object to be printed, it is possible to provide an inkjet printer that can suppress the irradiation of wasteful light that does not hit the photocurable ink ejected onto the object to be printed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

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Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0012] 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. It should be noted 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 descriptions are omitted or simplified as appropriate.

[0013] FIG. 1 is a perspective view of a printer 10 in the present embodiment. The printer 10 in the present embodiment is a flatbed type printer. 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. When the printer 10 is viewed from the front, the left, right, top, and bottom are simply expressed as left, right, top, and bottom. In the drawings, the reference numerals F, Rr, L, R, U, and D represent the front, rear, left, right, top, and bottom, respectively. The reference numeral Y in the drawings indicates the main scanning direction. Also, the reference numeral X in the drawings indicates the sub-scanning direction. Here, the main scanning direction Y is the left-right direction, and the sub-scanning direction X is the front-rear direction. The main scanning direction Y and the sub-scanning direction X are orthogonal. The reference numeral Z in the drawings indicates the up-down direction. The up-down direction Z is orthogonal to the main scanning direction Y and the sub-scanning direction X. The directions defined here are merely for convenience and do not limit the installation state of the printer 10, nor do they limit the present invention.

[0014] As shown in FIG. 2, the printer 10 can perform printing on the first printing object 5 placed on the table 20 described later. The first printing object 5 has a plane that extends at least partially in the main scanning direction Y and the sub-scanning direction X. For example, the first printing object 5 is recording paper or the like. However, the first printing object 5 is not limited to recording paper, and may be a sheet formed of a resin material, a metal plate, a glass plate, a wood plate, or the like. Further, the first printing object 5 may be a three-dimensional object such as a smartphone case.

[0015] As shown in FIG. 3, the printer 10 can also perform printing on the outer peripheral surface of the second printing object 6 while intermittently rotating the second printing object 6 using the rotation mechanism 90 described later. The second printing object 6 is a three-dimensional object, and the shape of the second printing object 6 includes a cylindrical shape and a tubular shape. The type of the second printing object 6 is not particularly limited, and examples thereof include a bottle and a cup. Further, the material of the second printing object 6 is not particularly limited, and may be glass, resin, wood, or the like.

[0016] As shown in FIG. 1, the printer 10 is formed in a box shape. The printer 10 includes a case 11 and a front cover 12. FIGS. 2 and 3 are front views of the printer 10 with the front cover 12 open. As shown in FIGS. 2 and 3, an opening 13 is formed in the front portion of the case 11. The front cover 12 is provided so as to be able to open and close the opening 13 formed in the case 11. Here, the front cover 12 is supported by the case 11 so as to be rotatable about the rear end of the front cover 12.

[0017] The front cover 12 is provided with a window portion 12a. The window portion 12a is formed of, for example, a transparent acrylic plate. The user can visually recognize the inside of the case 11 through the window portion 12a. The window portion 12a is configured so that the light irradiated from the light irradiation device 70 described later does not leak to the outside. Here, the window portion 12a is made of a material that does not transmit ultraviolet rays. Note that a process for blocking ultraviolet rays may be performed on the window portion 12a.

[0018] As shown in FIGS. 2 and 3, the printer 10 includes a table 20, a table moving device 30, a carriage 40, a carriage moving device 50, an ink head 60, a light irradiation device 70, a height detection device 80, and a control device 100 (see FIG. 1).

[0019] The table 20 is a base for supporting the first printed material 5 and the second printed material 6. The table 20 is a flat member and extends in the main scanning direction Y and the sub-scanning direction X. The table 20 is disposed substantially at the center in the main scanning direction Y inside the case 11.

[0020] Below the table 20, a table moving device 30 is disposed. The table moving device 30 moves the table 20 in the sub-scanning direction X and the vertical direction Z. The table 20 is supported from below by the table moving device 30. The table moving device 30 includes a sub-scanning direction moving device 30X and a vertical direction moving device 30Z. The vertical direction moving device 30Z supports the table 20 and moves it in the vertical direction Z. The sub-scanning direction moving device 30X supports the vertical direction moving device 30Z and moves it in the sub-scanning direction X. However, the configuration of the table moving device 30 is not limited to the above configuration. For example, the sub-scanning direction moving device 30X and the vertical direction moving device 30Z may have the reverse vertical positional relationship. As shown in FIG. 2, when printing on the first printed material 5, the printer 10 discharges ink onto the first printed material 5 while intermittently moving the table 20 forward. However, instead of intermittently moving the table 20 forward, the printer 10 may discharge ink onto the first printed material 5 while intermittently moving it backward to perform printing on the first printed material 5.

[0021] The carriage 40 is equipped with an ink head 60 and a light irradiation device 70. The ink head 60 is provided at the lower part of the carriage 40 and faces the table 20. Three ink heads 60 are provided. However, the number of ink heads 60 is not limited to this. The light irradiation device 70 is arranged to the left of the ink head 60. The carriage 40 is arranged above the table 20 and is provided to face the table 20. The carriage 40 can be moved in the main scanning direction Y by a carriage moving device 50.

[0022] The carriage moving device 50 includes a guide rail 51, a belt 52, left and right pulleys (not shown), and a carriage motor 53 (see FIG. 6). As shown in FIG. 2, the guide rail 51 extends in the main scanning direction Y. The carriage 40 is slidably engaged with the guide rail 51. The belt 52 is fixed to the carriage 40. The belt 52 is wound around pulleys (not shown) provided on the right side and the left side extending across the guide rail 51. The carriage motor 53 is attached to one of the pulleys. The carriage motor 53 is a driving device that moves the carriage 40 along the guide rail 51. The type of the carriage motor 53 is not particularly limited, but in this embodiment, it is a DC motor. When the carriage motor 53 is driven, the pulley rotates and the belt 52 runs. Thereby, the carriage 40 moves in the main scanning direction Y along the guide rail 51. Also, when the driving voltage of the carriage motor 53 changes, the rotational speed of the carriage motor 53 changes. However, the configuration of the carriage moving device 50 is not limited to this.

[0023] The ink head 60 discharges ink toward the first printed material 5 or the second printed material 6 placed on the table 20. The ink head 60 is communicated with an ink cartridge 15 (see FIG. 3) housed in the case 11 by flexible ink tubes (not shown), respectively. As shown in FIG. 4, the ink heads 60 are arranged at positions aligned in the sub-scanning direction X.

[0024] As shown in FIG. 4, the ink head 60 includes a nozzle surface 60b on which a plurality of nozzles 60a are respectively formed. The nozzle surface 60b faces downward and faces the first printed material 5 or the second printed material 6 placed on the table 20. The nozzle surface 60b extends in the sub-scanning direction X. The plurality of nozzles 60a are arranged in the sub-scanning direction X to form a nozzle row. In FIG. 4, two nozzle rows are formed in one ink head 60. The nozzle 60a is a fine hole from which ink is ejected. Each nozzle 60a communicates with a pressure chamber (not shown) in which ink is stored. The ink is ejected from the nozzle 60a, for example, when the pressure chamber expands or contracts by driving a piezoelectric element. In FIG. 4, 12 nozzles 60a are formed in one nozzle row, but actually, a larger number (for example, 300) of nozzles 60a are formed. The number of nozzles 60a formed in one nozzle row is not limited. Also, the number of nozzle rows is not particularly limited.

[0025] The ink used in this embodiment is a photocurable ink that cures when irradiated with light. In this embodiment, the photocurable ink is an ultraviolet curable ink that cures when irradiated with ultraviolet light. The components and properties of the photocurable ink are not particularly limited. Also, the color of the photocurable ink is not particularly limited.

[0026] The light irradiation device 70 irradiates light on the first printed material 5 or the second printed material 6 placed on the table 20. In this embodiment, the light irradiation device 70 is an ultraviolet irradiation device that irradiates ultraviolet light. As shown in FIG. 4, in the sub-scanning direction X, the light irradiation device 70 is longer than the ink head 60. Also, the rear end of the light irradiation device 70 and the rear end of the ink head 60 are at the same position with respect to the sub-scanning direction X.

[0027] The light irradiation device 70 includes an irradiation surface 72 facing downward and opposing the table 20, and a plurality of light sources 71 provided on the irradiation surface 72. In the present embodiment, the light source 71 is an LED element. The light sources 71 are arranged side by side in the sub-scanning direction X. In FIG. 4, the light irradiation device is provided with 20 light sources 71, but actually, a larger number of light sources 71 (for example, 100) are provided. However, the number of the light sources 71 is not particularly limited. The light irradiation device 70 has four divided lighting areas from A1 to A4. In FIG. 4, one divided lighting area includes 5 light sources 71. Each divided lighting area can be individually lit or extinguished. Also, in the present embodiment, since the light source 71 is an LED element, the light emission intensity of the light source 71 can be changed by changing the current input to the light irradiation device 70.

[0028] As shown in FIG. 2, the height detection device 80 is arranged above the table 20. The height detection device 80 measures the height of the first printed object 5 or the second printed object 6 placed on the table 20 from the table 20. The configuration of the height detection device 80 is not particularly limited. For example, the height detection device 80 may be a laser displacement meter configured to measure the height of the first printed object 5 or the second printed object 6 from the table 20 by irradiating the first printed object 5 or the second printed object 6 with a laser.

[0029] As described above, when printing on the outer peripheral surface of the second printed object 6, a rotation mechanism 90 for rotating the second printed object 6 is used. As shown in FIG. 3, the rotation mechanism 90 is placed on the table 20 and is configured to be detachable from the table 20. The rotation mechanism 90 rotates the second printed object 6 around an axis Ax extending in the main scanning direction Y. In the present embodiment, the rotation mechanism 90 rotates the second printed object 6 forward. Note that rotating the second printed object 6 forward means rotating the second printed object 6 so that the highest part of the second printed object 6 faces forward. However, the rotation mechanism 90 may rotate the second printed object 6 backward. Also, when printing the first printed object 5, the rotation mechanism 90 is removed from the table 20.

[0030] FIG. 5 is a perspective view of the rotating mechanism 90. The rotating mechanism 90 includes a first shaft 91, a second shaft 92, a rotation motor 93, a gear set 94, and a belt 95. The first shaft 91 extends in the main scanning direction Y and can rotate about an axis Ax extending in the main scanning direction Y. The first shaft 91 is connected to the rotation motor 93 via the gear set 94. The second shaft 92 is disposed in front of the first shaft 91. The second shaft 92, similar to the first shaft 91, extends in the main scanning direction Y and can rotate about an axis extending in the main scanning direction Y. The belt 95 is wound around the first shaft 91 and the second shaft 92. When the rotation motor 93 is driven, the first shaft 91 rotates, and the second shaft 92 also rotates together with the first shaft 91 by the belt 95. A rotary encoder is built in the rotation motor 93. Thereby, the rotation position of the rotation motor 93 can be grasped. However, the configuration of the rotating mechanism 90 is not limited to this. The rotating mechanism 90 may include a mechanism for gripping and rotating the second printed material 6.

[0031] FIG. 6 is a block diagram of the printer 10 according to the present embodiment. The control device 100 is electrically connected to the sub-scanning direction moving device 30X, the vertical direction moving device 30Z, the carriage motor 53 of the carriage moving device 50, the ink head 60, the light source 71 of the light irradiation device 70, the height detection device 80, and the rotation motor 93 of the rotation mechanism 90, and controls the operations thereof. The configuration of the control device 100 is not particularly limited. The control device 100 is, for example, a microcomputer or the like. In the present embodiment, the control device 100 is provided inside the printer 10. However, the control device 100 does not necessarily have to be provided inside the printer 10. For example, the control device 100 may be a computer or the like installed outside the printer 10 and communicably connected to the printer 10 via wire or wireless.

[0032] The control device 100 includes a discharge control unit 101, a light irradiation control unit 102, a carriage movement control unit 103, a table movement control unit 104, and a rotation control unit 105. The control device 100 may include other processing units, but the description and illustration thereof are omitted here.

[0033] The discharge control unit 101 controls the discharge of the photocurable ink by the ink head 60. As shown in FIG. 7, the distance between the second printing material 6 and the lower surface of the ink head 60 varies depending on the position in the sub-scanning direction X. That is, the distance between the second printing material 6 and the nozzle 60a varies depending on the position in the sub-scanning direction X. When the distance between the second printing material 6 and the nozzle 60a increases, splashing of the photocurable ink discharged from the nozzle 60a occurs, and the printing quality deteriorates. Therefore, when printing on the second printing material 6, in this embodiment, the range of the nozzles 60a that discharge the photocurable ink is restricted. In the following description, the range of the nozzles 60a that discharge the photocurable ink is referred to as the usage range of the nozzles 60a. The discharge control unit 101 determines the usage range of the nozzles 60a according to the curvature of the surface of the second printing material 6 when viewed from the main scanning direction Y. The symbol W in FIG. 7 shows an example of the usage range of the nozzles 60a.

[0034] The light irradiation control unit 102 controls the lighting or extinguishing of the light irradiation device 70 to control the irradiation of light on the second printing material 6. The light irradiation control unit 102 performs lighting or extinguishing control for each divided lighting area. In addition, the light irradiation control unit 102 can control the emission intensity of the light source 71 of the light irradiation device 70. The emission intensity of the light source 71 is controlled according to the moving speed of the carriage 40 in the main scanning direction Y and the amount of the photocurable ink discharged from the nozzles 60a.

[0035] The carriage movement control unit 103 controls the movement of the carriage 40 in the main scanning direction Y by controlling the carriage motor 53 of the carriage movement device 50. The carriage movement control unit 103 can control the movement speed of the carriage 40 by controlling the rotation speed of the carriage motor 53. The table movement control unit 104 controls the sub-scanning direction movement device 30X and the vertical direction movement device 30Z to control the movement of the table 20 in the sub-scanning direction X and the vertical direction Z. The rotation control unit 105 controls the rotation motor 93 to control the rotation of the second printing object 6.

[0036] Hereinafter, the operation of the printer 10 when printing on the first printing object 5 will be described. As described above, when printing on the first printing object 5, printing is performed while intermittently moving the table 20 forward in the sub-scanning direction X. FIG. 8 shows an example of a flowchart when printing on the first printing object 5. In step S01, the height of the first printing object 5 from the table 20 is measured by the height detection device 80. Based on the measurement result of the height of the first printing object 5, the table movement control unit 104 adjusts the position of the table 20 in the vertical direction Z so that it becomes a position suitable for printing. In step S02, while moving the carriage 40 in the main scanning direction Y, photocurable ink is ejected from the nozzle 60a. At this time, simultaneously, the light irradiation device 70 is lit, and the first printing object 5 is irradiated with light. When printing on the first printing object 5, the light irradiation control unit 102 lights all the light sources 71 of the light irradiation device 70. When the ejection of the photocurable ink at one position in the sub-scanning direction X is completed, the printing for one scan is completed. In step S03, the table 20 moves forward, and the printing position moves. Steps S02 and S03 are alternately repeated until the entire printing is completed.

[0037] Next, the operation of the printer 10 when printing on the second printing material 6 will be described. FIG. 9 is an example of a flowchart when printing on the second printing material 6. From step S11 to step S13, a setup operation is performed. In the setup operation, the vertical position Z of the table 20 is adjusted, the use range of the nozzle 60a is determined, and the lighting condition of the light irradiation device 70 is determined. Note that, in the setup operation, other operations may be performed, but the description thereof is omitted here. From step S14 to step 16, printing is performed on the second printing material 6.

[0038] In step S11, based on the height of the second printing material 6 from the table 20, the table movement control unit 104 adjusts the vertical position Z of the table 20. The height of the second printing material 6 from the table 20 is measured by the height detection device 80. The height of the second printing material 6 from the table 20 measured here refers to the distance from the upper surface of the table 20 to the highest position of the second printing material 6. The vertical position Z of the table 20 is adjusted so that the distance between the highest position of the second printing material 6 and the ink head 60 becomes a predetermined value (for example, 1 mm). Note that the height of the second printing material 6 from the table 20 may be calculated by the control device 100 based on the print data input by the user.

[0039] In step S12, the ejection control unit 101 determines the use range of the nozzle 60a according to the curvature of the second printing material 6 when viewed from the main scanning direction Y. In the present embodiment, only the nozzles 60a within a range where the distance between the nozzle 60a and the second printing material 6 is equal to or less than a predetermined value (for example, 2 mm or less) are used. Here, the method for obtaining or calculating the curvature of the surface of the second printing material 6 when viewed from the main scanning direction Y is not particularly limited. For example, it may be calculated by the control device 100 based on the print data input by the user.

[0040] In step S13, the light irradiation control unit 102 determines the lighting conditions of the light irradiation device 70. The light irradiation control unit 102 determines the divided lighting area of the light irradiation device 70 to be lit and the emission intensity of the light source 71 to be lit. Regarding the divided lighting area to be lit, in this embodiment, the light irradiation control unit 102 lights the divided lighting area that is at least partially in the same position as the usage range of the nozzle 60a determined in step S12 in the sub-scanning direction X. For example, in the case of FIG. 7, the light sources 71 in the divided lighting areas A1 and A2 are lit. The emission intensity of the light source 71 is determined by the light irradiation control unit 102 based on the moving speed of the carriage 40 in the main scanning direction Y, the ink ejection amount, etc. Here, the method for acquiring or calculating the moving speed of the carriage 40 and the ejection amount of the photocurable ink is not particularly limited. For example, the control device 100 may calculate based on the print data input by the user.

[0041] In step S14, while the carriage movement control unit 103 moves the carriage 40 in the main scanning direction Y, the ejection control unit 101 ejects the photocurable ink from the nozzle 60a. The photocurable ink is ejected only from the nozzle 60a within the usage range determined by the ejection control unit 101 in step S12. Thereby, printing is performed on the surface of the second printing material 6. At the same time in step S14, the light irradiation device 70 is lit and the second printing material 6 is irradiated with light. The light irradiation device 70 is lit based on the conditions determined by the light irradiation control unit 102 in step S13. Thereby, the photocurable ink ejected onto the second printing material 6 is cured. When the ejection of the photocurable ink at one rotational position is completed, the printing for one scan is finished. The width in the sub-scanning direction X of the printing for one scan is determined by the usage range of the nozzle 60a determined in step S12.

[0042] When the printing for one scan is completed, it is determined in step S15 whether the overall printing is completed. If the overall printing is not completed and printing is to be performed at other rotational positions, the process proceeds to step S16. In step S16, the rotation control unit 105 rotates the second printing object 6 by a predetermined angle. This predetermined angle is calculated by the control device 100 based on the use range of the nozzle 60a determined by the discharge control unit 101 in step S12. When step S16 ends, the process returns to step S14 again, and printing is performed on the second printing object 6. The operations from step S14 to step S16 are repeated until the overall printing is completed. When the overall printing is completed, the printer 10 ends its operation.

[0043] According to this embodiment, the printer 10 includes an ink head 60 having a lower surface on which a nozzle 60a for discharging photocurable ink is formed, a light irradiation device 70 disposed laterally of the ink head 60, a rotation mechanism 90 for rotating the second printing object 6 around the axis Ax, and a control device 100 for controlling the ink head 60, the light irradiation device 70, and the rotation mechanism 90. The light irradiation device 70 has four divided lighting areas from A1 to A4 in the sub-scanning direction X. Each divided lighting area can be lit or extinguished individually. The control device 100 has a light irradiation control unit 102 that can individually control the lighting and extinguishing of these divided lighting areas. Thereby, while extinguishing the divided lighting areas that irradiate hard-to-hit light on the photocurable ink discharged onto the second printing object 6, only the divided lighting areas that irradiate easy-to-hit light on the photocurable ink discharged onto the second printing object 6 can be lit. Therefore, wasteful light irradiation can be suppressed.

[0044] Since the outer peripheral surface of the cylindrical object to be printed is convexly curved, the distance between the nozzle 60a and the second object to be printed 6 varies depending on the position in the sub-scanning direction X. When the distance between the nozzle 60a and the second object to be printed 6 becomes large, the splashing of the photocurable ink is likely to occur and the landing position is also likely to shift. However, according to the present embodiment, the ejection control unit 101 of the control device 100 determines the use range of the nozzle 60a according to the curvature of the surface of the second object to be printed 6 as viewed from the main scanning direction Y. Thereby, the photocurable ink can be ejected only from the nozzle 60a having an appropriate distance between the nozzle 60a and the second object to be printed 6. Therefore, the printing quality is stabilized.

[0045] The light irradiation control unit 102 of the control device 100 determines the divided lighting area to be lit according to the use range of the nozzle 60a determined by the ejection control unit 101. In the present embodiment, the light irradiation control unit 102 lights the divided lighting area of the light irradiation device 70 that is at least partially in the same position as the use range of the nozzle 60a determined by the ejection control unit 101 with respect to the sub-scanning direction X. Thereby, it is possible to light the divided lighting area that irradiates the photocurable ink ejected onto the second object to be printed 6 while turning off the divided lighting area that is less likely to irradiate the photocurable ink ejected onto the second object to be printed 6. Therefore, wasteful light irradiation can be suppressed.

[0046] According to the present embodiment, the light irradiation control unit 102 can control the emission intensity of the light source 71. That is, the light irradiation control unit 102 can control the intensity of the light irradiated by the light irradiation device 70. By adjusting the intensity of the light according to various conditions during printing, it is possible to irradiate the photocurable ink ejected onto the second object to be printed 6 with light of an appropriate intensity.

[0047] According to this embodiment, the carriage 40 is movable in the main scanning direction Y by a carriage moving device 50. The light irradiation control unit 102 controls the intensity of the light irradiated from the light irradiation device 70 according to the moving speed of the carriage 40 in the main scanning direction Y. The degree of curing of the photocurable ink is determined by the irradiation time of the light and the intensity of the light. When the moving speed of the carriage 40 changes, the irradiation time of the light changes. By irradiating light with an appropriate intensity with respect to the moving speed of the carriage 40, it is possible to suppress insufficient curing of the photocurable ink discharged onto the second printing material 6 and prevent excessive light irradiation.

[0048] According to this embodiment, the light irradiation control unit 102 controls the intensity of the light irradiated by the light irradiation device according to the amount of the photocurable ink discharged from the nozzle 60a. The intensity of the light that the light irradiation device 70 should irradiate differs depending on the amount of the photocurable ink to be cured. By irradiating light with an appropriate intensity with respect to the amount of the photocurable ink discharged from the nozzle 60a, it is possible to suppress insufficient curing of the photocurable ink discharged onto the second printing material 6 and prevent excessive light irradiation.

[0049] As described above, one embodiment of the present invention has been described, but the above embodiment is merely an example. Various other embodiments are possible.

[0050] In the above embodiment, the drive source of the rotation mechanism 90 is the rotation motor 93, but the configuration of the rotation mechanism 90 is not limited to this. For example, the printer 10 may include a rack and pinion mechanism that can convert linear motion into rotational motion. A rack may be provided on the table 20, a pinion may be provided on the rotation mechanism 90, and the rotation mechanism 90 may be configured so that the linear motion of the table 20 moving in the sub-scanning direction X can be converted into the rotational motion of the second printing material 6 rotating.

[0051] In the above embodiment, the number of divided lighting areas is four, but the number of divided lighting areas is not limited to this. When the number of divided lighting areas is large, the control device 100 has a complicated configuration, but unnecessary light irradiation can be further suppressed.

[0052] In the above embodiment, as shown in FIG. 4, the number of light sources 71 provided in one divided lighting area was five, but the number of light sources 71 provided in one divided lighting area is not particularly limited. Further, in the above embodiment, each divided lighting area had the same number of light sources 71, but the number of light sources 71 provided in each divided lighting area may be different from each other.

[0053] In the above embodiment, in the sub-scanning direction X, the rear end of the light irradiation device 70 and the rear end of the ink head 60 were at the same position. However, the positional relationship between the light irradiation device 70 and the ink head 60 is not particularly limited. For example, as shown in FIG. 10, in the sub-scanning direction X, the light irradiation device 70 may be arranged such that the central portion of the ink head 60 and the central portion of the light irradiation device 70 are at the same position. In the case of FIG. 10, the divided lighting areas to be lit are A2 and A3.

[0054] In the above embodiment, in the sub-scanning direction X, the length of the light irradiation device 70 was longer than the length of the ink head 60, but it is not limited thereto. In the sub-scanning direction X, the length of the light irradiation device 70 and the length of the ink head 60 may be the same, or the ink head 60 may be longer than the light irradiation device 70.

[0055] In the above embodiment, a plurality of ink heads 60 were arranged at the same position in the sub-scanning direction X, but it is not limited thereto. For example, as shown in FIG. 11, two ink heads 60 may be arranged side by side at different positions in the sub-scanning direction X. That is, the ink heads 60 may be stagger arranged. In the case of FIG. 11, the divided lighting areas to be lit are A2 and A3.

[0056] In the above-described embodiment, the light irradiation device 70 was arranged to the left of the ink head 60. However, the positional relationship between the light irradiation device 70 and the ink head 60 is not limited to this. The light irradiation device 70 may be arranged to the right of the ink head 60. Also, in the above-described embodiment, the number of light irradiation devices 70 was one, but it is not limited to this. For example, there may be two light irradiation devices 70, and one may be arranged on each of the left and right sides of the ink head 60.

Explanation of Reference Numerals

[0057] 5 First Printed Object 6 Second Printed Object (Printed Object) 10 Printer 40 Carriage 60 Ink Head 60a Nozzle 70 Light Irradiation Device 71 Light Source 90 Rotation Mechanism 100 Control Device 101 Discharge Control Unit 102 Light Irradiation Control Unit

Claims

1. An inkjet printer comprising: an ink head having a lower surface formed with nozzles for discharging photocurable ink onto a three-dimensional printed object, the nozzles being arranged side by side in a sub-scanning direction; a light irradiation device arranged on a side of the ink head, having a plurality of divided lighting areas arranged in the sub-scanning direction, the divided lighting areas being individually lightable or extinguishable; a rotation mechanism for rotating the printed object around an axis orthogonal to the sub-scanning direction; and a control device having a light irradiation control unit for individually controlling lighting and extinguishing of the divided lighting areas.

2. The control device includes a discharge control unit that determines a use range of the nozzles according to a curvature of a surface of the printed object when viewed from an axial direction, The inkjet printer according to claim 1, wherein the light irradiation control unit determines the divided lighting areas to be lit according to the use range of the nozzles determined by the discharge control unit.

3. The inkjet printer according to claim 2, wherein the light irradiation control unit lights the divided lighting areas that are at least partially in the same position as the use range of the nozzles determined by the discharge control unit in the sub-scanning direction.

4. The inkjet printer according to claim 1, wherein the light irradiation control unit controls an intensity of light irradiated by the light irradiation device.

5. The inkjet printer includes a carriage on which the ink head and the light irradiation device are mounted and which is movable in a main scanning direction orthogonal to the sub-scanning direction, The inkjet printer according to claim 4, wherein the light irradiation control unit controls an intensity of light irradiated by the light irradiation device according to a moving speed of the carriage in the main scanning direction.

6. The inkjet printer according to claim 4, wherein the light irradiation control unit controls an intensity of light irradiated by the light irradiation device according to an amount of the photocurable ink discharged from the nozzles.

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