Printing apparatus and printing method

Abstract

Provided are a printing apparatus and a printing method capable of reducing a peak value of a current or a voltage required for irradiation of light while suppressing an influence on curing of ink landing on a recording medium. A printing apparatus (10) includes: an ink ejection head (40) that ejects a photocurable ink toward a medium (22) while moving relative to the medium (22) in a main scanning direction (Y); and an irradiation unit (32) that irradiates light to the medium (22) while moving relative to the ink ejection head (40), in which the irradiation unit (32) has a plurality of LEDs (34) arranged in a sub-scanning direction (X) intersecting with the main scanning direction (Y), the printing apparatus (10) is provided with an irradiation control unit (60) that controls the irradiation unit (32), and the irradiation unit (32) emits light to the medium (22) while moving relative to the ink ejection head (40). During one cycle in which the ink ejection head (40) and the irradiation unit (32) move relative to each other in the main scanning direction (Y), the on / off of the irradiation of the plurality of LEDs (34) is repeated in a predetermined order.

Description

Technical Field

[0001] The invention relates to a printing device and a printing method. Background Art

[0002] Conventionally, there has been developed a printing device that discharges photocurable ink onto a recording medium and forms an image by irradiating the ink landed on the recording medium with ultraviolet light or the like to cure the ink.

[0003] Such a printing device using photocurable ink includes an irradiation unit that irradiates ultraviolet rays for curing the ink, as described in Patent Document 1. The irradiation unit is provided in a carriage unit, and a nozzle head that ejects ink is mounted on the carriage unit.

[0004] Existing patent literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 2015-74161 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The irradiation unit applies a load to the printing device by irradiating light for sufficiently curing the ink landed on the recording medium. In order to reduce the load applied by the irradiation unit to the printing device, it is required to reduce the peak value of the current or voltage required for irradiation of light.

[0009] Therefore, an object of the present invention is to provide a printing apparatus and a printing method capable of reducing a peak value of a current or a voltage required for irradiation with light while suppressing an influence on curing of ink landed on a recording medium.

[0010] Solutions for solving problems

[0011] A printing device of a first embodiment of the present invention comprises: an ink ejection unit, which ejects photocurable ink toward a recording medium while moving relative to the recording medium in a first direction; and an irradiation unit, which irradiates light toward the recording medium while moving relative to the ink ejection unit, wherein the irradiation unit has a plurality of light irradiation elements arranged in a second direction intersecting the first direction, and the printing device is provided with an irradiation control unit, which controls the irradiation unit so that during one cycle of relative movement of the ink ejection unit and the irradiation unit in the first direction, the irradiation of the plurality of light irradiation elements is repeatedly turned on and off in a prescribed order.

[0012] According to this structure, light-curable ink is ejected toward the recording medium while moving relative to the recording medium in the first direction. A plurality of light irradiation elements for irradiating light for curing the ink are arranged in the irradiation unit in a second direction intersecting the first direction, and the irradiation unit moves relative to the recording medium in the first direction together with the ink ejection unit.

[0013] Furthermore, the present structure repeatedly turns on and off the irradiation of the plurality of light irradiation elements in a predetermined order during one cycle of relative movement of the ink ejection unit and the irradiation unit in the first direction. That is, the irradiation of light for curing the ink landed on the recording medium is performed in a manner that staggers the timing of turning on and off the plurality of light irradiation elements. Thus, the present structure can reduce the peak value of the current or voltage required for the irradiation of light while suppressing the influence on the curing of the ink landed on the recording medium.

[0014] As a printing apparatus according to a second aspect, in the printing apparatus according to the first aspect, the irradiation control unit may control the irradiation unit so that the irradiation of the plurality of light irradiation elements is repeatedly turned on and off in a predetermined order along the second direction.

[0015] As a third-type printing device, it may also be that, in a printing device of the first type or the second type, the irradiation control unit turns on irradiation of other light irradiation elements after a first time has passed since irradiation of the specified light irradiation element was turned on, the irradiation control unit turns off irradiation of the specified light irradiation element after a second time has passed since irradiation of the specified light irradiation element was turned on, and turns on irradiation of the specified light irradiation element after a third time has passed since irradiation of the specified light irradiation element was turned off.

[0016] As a printing apparatus according to a fourth aspect, in the printing apparatus according to the third aspect, the first time may be shorter than the second time and the third time, and the second time may be longer than the third time.

[0017] As a printing apparatus according to a fifth aspect, in the printing apparatus according to any one of the first to fourth aspects, a time period in which all of the plurality of light irradiation elements are turned off simultaneously is not generated.

[0018] As a sixth aspect of the printing device, in the printing device of any one of the first to fifth aspects, the plurality of light irradiation elements may be divided into a plurality of groups, and the irradiation control unit may control irradiation of the light irradiation elements for each of the groups.

[0019] As a seventh mode of printing device, it may also be that, in the sixth mode of printing device, the irradiation control unit turns on the irradiation of the light irradiation elements included in the other groups adjacent to the specified group after a specified time has passed since the irradiation of the light irradiation elements included in the specified group was turned on.

[0020] In an eighth printing method, an ink ejection unit ejects photocurable ink toward a recording medium while moving relative to the recording medium in a first direction, and an irradiation unit irradiates light toward the recording medium while moving relative to the ink ejection unit. The irradiation unit includes a plurality of light irradiation elements arranged in a second direction intersecting the first direction. The irradiation unit is controlled so that during one cycle of relative movement of the ink ejection unit and the irradiation unit in the first direction, the irradiation of the plurality of light irradiation elements is repeatedly turned on and off in a prescribed order.

[0021] Effects of the Invention

[0022] An object of the present invention is to provide a printing apparatus and a printing method capable of reducing a peak value of a current or a voltage required for irradiation with light while suppressing an influence on curing of ink landed on a recording medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the configuration of a printing device according to an embodiment.

[0024] Figure 2 1 and 2 are external views of a carriage according to an embodiment, wherein (A) is a front view and (B) is a bottom view.

[0025] Figure 3 It is a cross-sectional view of the irradiation portion according to the embodiment.

[0026] Figure 4 This is a functional block diagram of an irradiation unit according to an embodiment.

[0027] Figure 5 This is a timing chart of turning on and off the conventional irradiation unit.

[0028] Figure 6 It is a timing chart of turning on and off the irradiation unit according to the embodiment.

[0029] Figure 7 1 and 10 are diagrams showing the current consumption of the irradiation unit. (A) shows the current consumption of the conventional irradiation unit, and (B) shows the current consumption of the irradiation unit according to the embodiment.

[0030] Figure 8 Schematic diagram showing average illuminance distribution according to the embodiment. DETAILED DESCRIPTION

[0031] Next, a printing device 10 according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 1 is a schematic overall view of the printing device 10 of the present embodiment. The printing device 10 of the present embodiment is a so-called inkjet printer as described below.

[0032] like Figure 1 As shown, the printing device 10 includes legs 12 installed on the ground, and a main body 14 disposed on the upper side (Z direction) of the legs 12. The main body 14 includes a guide rail 16, a carriage 18, a platen 20, and the like.

[0033] The guide rail 16 extends in the left-right direction (main scanning direction Y) of the printing device 10 and is used to guide the carriage 18 to move in the scanning direction. The carriage 18 carries one or more ink ejection heads 40 (see Figure 2 ), the carriage 18 ejects ink onto the medium 22 while moving along the guide rail 16 in the main scanning direction Y. In the following description, a first direction in which the carriage 18 moves relative to the medium 22 is referred to as the main scanning direction Y, and a second direction intersecting (orthogonal in this embodiment) the main scanning direction Y is referred to as the sub-scanning direction X.

[0034] The platen 20 is a mounting table for mounting the medium 22. The medium 22 mounted on the platen 20 is transported by the transport mechanism in the secondary scanning direction X. The medium 22 may be a sheet-shaped recording medium such as paper, vinyl chloride film, rubber sheet, or cloth.

[0035] Figure 2 This is an external view of the carriage 18 according to the present embodiment. Figure 2 (A) is a front view of the slide 18. Figure 2 (B) is a bottom view of the carriage 18 . The carriage 18 has a plurality of ink ejection heads 40 mounted inside a carriage body 30 .

[0036] The nozzle 42 for ejecting ink from the ink ejection head 40 to the medium 22 is exposed on the bottom surface of the carriage body 30. The ink ejected from the ink ejection head 40 is a photocurable ink, and in this embodiment, it is cured by ultraviolet light. Therefore, the carriage 18 is equipped with an irradiation unit 32 for irradiating light (ultraviolet light) to cure the ink landed on the medium 22.

[0037] The irradiation unit 32 of the present embodiment is provided on the carriage 18 in a pair of left and right portions on the main scanning direction Y side so as to sandwich the inkjet head 40. Thus, the irradiation unit 32 irradiates light onto the medium 22 while relatively moving together with the inkjet head 40. In the following description, when distinguishing between the left and right irradiation units 32 provided on the carriage 18, R or L is added at the end to distinguish them.

[0038] In addition, the irradiation unit 32 of the present embodiment arranges a plurality of light irradiation elements (hereinafter referred to as "LEDs") 34 in the main scanning direction Y and the sub-scanning direction X. The irradiation unit 32 of the present embodiment arranges a total of 84 LEDs 34 in three columns in the main scanning direction Y and 28 rows in the sub-scanning direction X. The number and arrangement of the LEDs 34 are examples, and any amount of light that can cure the ink landed on the medium 22 may be used.

[0039] Figure 3 : is a cross-sectional view of the irradiation unit 32 of the embodiment. The irradiation unit 32 is provided with an LED substrate 50 on which LEDs 34 are arranged. The LED substrate 50 also generates heat together with the light emission of the LEDs 34. Therefore, a heat sink 52 for heat dissipation integrated with the LED substrate 50 is provided on the upper part of the LED substrate 50. Moreover, a fan 54 is provided above the heat sink 52 to cool the heat sink 52. As described above, the irradiation unit 32 of the present embodiment is air-cooled in order to cool the LEDs 34 that generate heat, but is not limited thereto, and the LEDs 34 may also be cooled by water cooling.

[0040] In addition, the shapes, sizes, etc. of the LED substrate 50 , the heat sink 52 , and the fan 54 are appropriately optimized according to the number and arrangement of the LEDs 34 included in the irradiation unit 32 .

[0041] Figure 4 3 is a functional block diagram of the irradiation unit 32 of this embodiment. The printing device 10 of this embodiment includes an irradiation control unit 60 and a plurality of driver ICs 62. Figure 4 In the figure, the irradiation unit 32L is shown, but the irradiation unit 32R is also similar, and the LED 34 is connected to the irradiation control unit 60 via the driver IC 62.

[0042] The irradiation control unit 60 performs drive control of the LED 34 by outputting a drive signal for turning the LED 34 on or off to the driver IC 62 .

[0043] The irradiation control unit 60 can perform different drive controls on the irradiation unit 32R and the irradiation unit 32L according to the position and the moving direction of the carriage 18 in the main scanning direction Y. The position of the carriage 18 in the main scanning direction Y is determined by the irradiation control unit 60 based on the signal from the encoder. For example, according to the moving direction of the carriage 18 with respect to the main scanning direction Y, either the irradiation unit 32R or the irradiation unit 32L is driven, or when the carriage 18 reaches a predetermined position in the main scanning direction Y, the irradiation unit 32R or the irradiation unit 32L is driven.

[0044] The driver IC 62 turns on or off the connected LED 34 based on the driving signal output from the irradiation control unit 60. The LED 34 of the present embodiment is virtually divided into a plurality of groups in the sub-scanning direction X. That is, the irradiation control unit 60 of the present embodiment outputs a driving signal for controlling the irradiation of the LED 34 to the driver IC 62 for each group. The driver IC 62 drives the LED 34 for each group based on the driving signal from the irradiation control unit 60.

[0045] In this embodiment, if Figure 4 As shown in the example, the LEDs 34 are grouped in such a way that each group has 2 rows, that is, each group has 6 LEDs. The number of LEDs 34 set as a group is not limited to this. In addition, in the following description, the group is also called a lighting block, and a number is marked at the end to distinguish it. That is, the multiple LEDs 34 possessed by the irradiation part 32L of this embodiment are divided into groups of lighting blocks 1 to 14, and 14 driver ICs 62 are driven for each lighting block. In addition, the multiple LEDs 34 possessed by the irradiation part 32R are divided into groups of lighting blocks 15 to 28, and 14 driver ICs 62 are driven for each lighting block.

[0046] The irradiation control unit 60 of this embodiment performs drive control of the LED 34 through PWM (Pulse Width Modulation) control. In this embodiment, the drive control of the LED 34 is performed by current control with a constant voltage, but the present invention is not limited thereto, and the drive control of the LED 34 may also be performed by voltage control with a constant current.

[0047] Here, Figure 5 32 is a timing chart of the conventional on (lighting) and off (extinguishing) of the irradiation unit 32. Figure 5 In the example of , all lighting blocks 1 to 28 are repeatedly turned on and off at the same timing.

[0048] On the other hand, the irradiation control unit 60 of the present embodiment controls the irradiation unit 32 so that during one cycle of relative movement of the carriage 18 in the main scanning direction Y, the irradiation of the plurality of LEDs 34 is repeatedly turned on and off in a predetermined order.

[0049] Figure 6 : is a timing chart of the on and off of the irradiation unit 32 of this embodiment. Figure 6 As shown, the irradiation control unit 60 of the present embodiment controls the irradiation unit 32 so that the irradiation of the plurality of LEDs 34 (lighting blocks) is repeatedly turned on and off in a predetermined order along the sub-scanning direction X.

[0050] Specifically, the illumination control unit 60 turns on the illumination of other lighting blocks after a first time (hereinafter referred to as "interval time T1") has passed since the illumination of the specified lighting block was turned on. Furthermore, the illumination control unit 60 turns off the illumination of the lighting block after a second time (hereinafter referred to as "lighting time T2") has passed since the illumination of the lighting block was turned on, and turns on the illumination of the lighting block after a third time (hereinafter referred to as "extinguishing time T3") has passed since the illumination of the lighting block was turned off.

[0051] exist Figure 6 In the example, the irradiation control unit 60 turns on the irradiation of the adjacent lighting block 2 after an interval time T1 has passed since the irradiation of the lighting block 1 was turned on. Furthermore, the irradiation control unit 60 turns off the irradiation of the lighting block 1 after a lighting time T2 has passed since the irradiation of the lighting block 1 was turned on, and turns on the irradiation of the lighting block 1 again after an extinguishing time T3 has passed. In addition, the irradiation control unit 60 turns on the irradiation of the lighting block 3 adjacent to the lighting block 2 after an interval time T1 has passed since the irradiation of the lighting block 2 was turned on, and performs this action until the lighting block 28 is turned on. In this way, in the drive control of the present embodiment, the irradiation is repeatedly turned on and off with staggered timing for each of the adjacent lighting blocks in the sub-scanning direction X.

[0052] Here, one cycle of PWM control of the irradiation unit 32 (one lighting and extinguishing) needs to be sufficiently shorter than one cycle of movement of the carriage 18 in the main scanning direction Y. If one cycle of PWM control is not sufficiently shorter than the movement cycle of the carriage 18, the ink landed on the medium 22 may not be properly cured.

[0053] In addition, the interval time T1 of the present embodiment is shorter than the lighting time T2 and the extinguishing time T3, and the lighting time T2 is longer than the extinguishing time T3. The reason why the lighting time T2 is longer than the extinguishing time T3 is to obtain sufficient illumination for curing the ink. The reason why the interval time T1 is shorter than the lighting time T2 and the extinguishing time T3 is the same. If the interval time T1 is longer, sufficient illumination for curing the ink cannot be obtained.

[0054] In addition, Figure 5 In the conventional drive control shown in FIG. 1 , all the LEDs 34 are turned on and off at the same timing. Therefore, a time period in which all the LEDs 34 are turned off occurs. On the other hand, in the drive control of the present embodiment, the timing of turning on the LEDs 34 is staggered so that a time period in which all the LEDs 34 are turned off does not occur. For example, when referring to FIG. Figure 6When the lighting block 1 is turned off, the other lighting blocks are also turned on, and one block is always turned off. By the drive control of this embodiment, it is possible to simultaneously achieve a reduction in peak current compared to the past and obtain sufficient illumination for curing the ink.

[0055] Figure 7 This is a diagram showing an example of the current consumption of the irradiation unit 32 . Figure 7 (A) shows the current consumption of the conventional irradiation unit 32. Figure 7 (B) shows the current consumption of the irradiation unit 32 of this embodiment. The peak value of the current consumption of the irradiation unit 32 of the conventional embodiment is 11.2 A, while the peak value of the current consumption of the irradiation unit 32 of this embodiment is 8.0 A. As described above, the peak value of the current consumption of the irradiation unit 32 of this embodiment is significantly smaller than that of the conventional embodiment.

[0056] In addition, the irradiation control unit 60 of this embodiment is as follows Figure 6 As shown, as an example, after the interval time T1 has passed since the illumination of the lighting block 14 of the illumination unit 32L was turned on, the illumination of the lighting block 15 of the illumination unit 32R is turned on. In this way, the drive control overlap of the left and right illumination units 32R and 32L can be suppressed, thereby reducing the current peak of the illumination unit 32.

[0057] Figure 8 Schematic diagram showing average illuminance distribution in the irradiation section 32L of the present embodiment. Figure 8 In the figure, the darker the shaded area, the higher the illumination. Figure 8 As shown in FIG. 1 , the illumination of the central portion of the irradiation portion 32L is higher than that of the periphery thereof. The central portion of the irradiation portion 32L is the same region as the region where the nozzles 42 for ejecting ink are arranged in the carriage 18 (see FIG. 1 ). Figure 3 ) Therefore, in the drive control of the present embodiment, it is possible to achieve an illumination distribution suitable for curing the ink landed on the medium 22 and reduce the current peak value of the irradiation unit 32.

[0058] As described above, the printing device 10 of the present embodiment repeatedly turns on and off the irradiation of the plurality of LEDs 34 in the sub-scanning direction X in a predetermined order during one cycle of relative movement of the carriage 18 in the main scanning direction Y. That is, the printing device 10 of the present embodiment irradiates light for curing the ink landed on the medium 22 in a manner that the timing of turning on and off the plurality of LEDs 34 is staggered along the sub-scanning direction X. As a result, the printing device 10 of the present embodiment can reduce the peak current of the irradiation unit 32 compared to the conventional method, and thus can reduce the peak current required for irradiation of light while suppressing the influence on the curing of the ink landed on the medium 22.

[0059] The present invention has been described above using the above embodiments, but the protection scope of the present invention is not limited to the scope described in the above embodiments. Various changes or improvements can be applied to the above embodiments without departing from the gist of the invention, and the methods obtained by applying the changes or improvements are also included in the protection scope of the present invention.

[0060] In the above-mentioned embodiment, a method of staggering the timing of setting the illumination to on for each lighting block is described, but the present invention is not limited thereto. For example, instead of staggering the timing of setting to on for each lighting block, a method of staggering the timing of setting to on for each LED 34 divided into a plurality of lighting blocks may be used. In addition, the following method may be used: instead of staggering the timing of setting the illumination to on in the order from lighting block 28 to lighting block 1, the timing of staggering the illumination to on may be used, or the timing of staggering the illumination to on may be used in the order from lighting block 7 or lighting block 8 in the central part to lighting block 1 or lighting block 14 at the end. In addition, instead of lighting the lighting block 29 of the illumination section 32R after the lighting block 28 of the illumination section 32L, the lighting blocks of the illumination section 32L and the lighting blocks of the illumination section 32R may be turned on and off at the same timing.

[0061] In the above embodiment, the drive control of the LEDs 34 is performed for each group (lighting block) including a specified number of LEDs 34. However, the present invention is not limited to this, and the drive control may be performed for each LED 34 instead of the LEDs 34 being grouped.

[0062] In addition, in the above embodiment, a method of staggering the timing of turning on the plurality of LEDs 34 in the sub-scanning direction X is described, but the present invention is not limited thereto, and a method of staggering the timing of turning on the plurality of LEDs 34 in the main scanning direction Y may be used. In this method, the plurality of LEDs 34 may be virtually divided into a plurality of groups in the main scanning direction Y.

[0063] (Effects of Embodiments)

[0064] (1) The printing device 10 of the present embodiment comprises: an inkjet head 40 that ejects light-curable ink toward the medium 22 while moving relative to the medium 22 in the main scanning direction Y; and an irradiation unit 32 that irradiates light toward the medium 22 while moving relative to the inkjet head 40, wherein the irradiation unit 32 has a plurality of LEDs 34 arranged in a sub-scanning direction X that intersects the main scanning direction Y, and the printing device 10 has an irradiation control unit 60 that controls the irradiation unit 32 so that during one cycle of relative movement of the inkjet head 40 and the irradiation unit 32 in the main scanning direction Y, the irradiation of the plurality of LEDs 34 is repeatedly turned on and off in a prescribed order.

[0065] According to the present embodiment, light-curable ink is ejected onto the medium 22 while moving relative to the medium 22 in the main scanning direction Y. A plurality of LEDs 34 for emitting light for curing ink are arranged in the irradiation unit 32 in the sub-scanning direction X intersecting the main scanning direction Y, and the irradiation unit 32 moves relative to the medium 22 in the main scanning direction Y together with the ink ejection head 40.

[0066] Furthermore, according to the present embodiment, during one cycle of relative movement of the ink ejection head 40 and the irradiation unit 32 in the main scanning direction Y, the irradiation of the plurality of LEDs 34 is repeatedly turned on and off in a predetermined order. That is, the irradiation of light for curing the ink landed on the medium 22 is performed in a manner that the timing of turning on and off the plurality of LEDs 34 is staggered. Thus, it is possible to reduce the peak value of the current required for the irradiation of light while suppressing the influence on the curing of the ink landed on the medium 22. In addition, in the present embodiment, the driving control of the LED 34 is performed by current control with a constant voltage to reduce the peak value of the current, but it is also possible to reduce the peak value of the voltage required for the irradiation of light by performing the driving control of the LED 34 with a constant current control.

[0067] (2) The irradiation control unit 60 of this embodiment controls the irradiation unit 32 so as to repeatedly turn on and off the irradiation of the plurality of LEDs 34 in a predetermined order along the secondary scanning direction X. According to this embodiment, it is possible to reduce the peak value of the current required for irradiation with light while suppressing the influence on the curing of the ink landed on the medium 22.

[0068] (3) The irradiation control unit 60 of the present embodiment turns on the irradiation of other LEDs 34 after the interval time T1 has passed since the irradiation of a specified LED 34 was turned on, turns off the irradiation of the LED 34 after the lighting time T2 has passed since the irradiation of the LED 34 was turned on, and turns on the irradiation of the LED 34 after the extinguishing time T3 has passed since the irradiation of the LED 34 was turned off. According to the present embodiment, it is possible to reduce the peak value of the current required for the irradiation of light while suppressing the influence on the curing of the ink landed on the medium 22.

[0069] (4) In this embodiment, the interval time T1 is shorter than the lighting time T2 and the extinguishing time T3, and the lighting time T2 is longer than the extinguishing time T3. According to this embodiment, the peak value of the current required for light irradiation can be reduced while suppressing the influence on the curing of the ink landed on the medium 22.

[0070] (5) The irradiation control unit 60 of this embodiment prevents a time period in which all the LEDs 34 are turned off. According to this embodiment, the peak value of the current required for irradiation with light can be reduced while suppressing the influence on the curing of the ink landed on the medium 22 .

[0071] (6) The plurality of LEDs 34 of this embodiment are divided into a plurality of groups, and the irradiation control unit 60 controls the irradiation of the LEDs 34 for each group. According to this embodiment, the peak value of the current required for irradiation with light can be reduced while suppressing the influence on the curing of the ink landed on the medium 22.

[0072] (7) The irradiation control unit 60 of the present embodiment turns on the irradiation of the LEDs 34 included in another adjacent group after a predetermined time has passed since the irradiation of the LEDs 34 included in the predetermined group was turned on. According to the present embodiment, it is possible to reduce the peak value of the current required for irradiation with light while suppressing the influence on the curing of the ink landed on the medium 22.

[0073] Description of Reference Numerals

[0074] 10: printing device; 18: ink ejection head (ink ejection unit); 22: medium (recording medium); 32: irradiation section (irradiation unit); 34: LED (light irradiation element); 60: irradiation control section (irradiation control unit).

Claims

1. A printing device comprising: an ink ejection unit that ejects light-curable ink toward a recording medium while moving relative to the recording medium in a first direction; and an irradiation unit that irradiates light toward the recording medium while moving relative to the ink ejection unit. in, The irradiation unit includes a plurality of light irradiation elements arranged in a second direction intersecting the first direction, The printing device includes an irradiation control unit that controls the irradiation unit so that irradiation of the plurality of light irradiation elements is repeatedly turned on and off in a predetermined order during one cycle of relative movement of the ink ejection unit and the irradiation unit in the first direction.

2. The printing device according to claim 1, wherein: The irradiation control unit controls the irradiation unit so that turning on and off of irradiation by the plurality of light irradiation elements is repeatedly performed in a prescribed order along the second direction.

3. The printing device according to claim 1 or 2, wherein: The irradiation control unit turns on the irradiation of the other light irradiation elements after a first time has passed since the irradiation of the predetermined light irradiation element was turned on, The irradiation control unit turns off the irradiation of the specified light irradiation element after a second time has passed since the irradiation of the specified light irradiation element was turned on, and turns on the irradiation of the specified light irradiation element after a third time has passed since the irradiation of the specified light irradiation element was turned off.

4. The printing device according to claim 3, wherein: The first time is shorter than the second time and the third time, The second time is longer than the third time.

5. The printing device according to claim 1 or 2, wherein: The illumination control unit prevents a time period in which all of the plurality of light irradiation elements are turned off simultaneously from occurring.

6. The printing device according to claim 1 or 2, wherein: The plurality of light irradiation elements are divided into a plurality of groups, The irradiation control unit controls irradiation of the light irradiation element for each of the groups.

7. The printing device according to claim 6, wherein: The irradiation control unit turns on the irradiation of the light irradiation elements included in the other groups adjacent to the specified group after a specified time has passed since the irradiation of the light irradiation elements included in the specified group was turned on.

8. A printing method, wherein: The ink ejection unit ejects light-curable ink toward the recording medium while moving relative to the recording medium in a first direction. The irradiation unit irradiates light toward the recording medium while relatively moving together with the ink ejection unit. The irradiation unit includes a plurality of light irradiation elements arranged in a second direction intersecting the first direction, The irradiation unit is controlled so that the irradiation of the plurality of light irradiation elements is repeatedly turned on and off in a predetermined order during one cycle in which the ink ejection unit and the irradiation unit move relative to each other in the first direction.

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