Printing device

Abstract

To provide a printer capable of restraining degradation of a printing image quality resulting from the shape of printing media.SOLUTION: A printer 10 comprises: a head 20 discharging a liquid to a printing medium A; a light irradiation part 30 irradiating the liquid on the printing medium with light; a relative displacement unit 40 relatively moving the printing medium A, the head and the light irradiation part in a movement direction along which the head and the light irradiation part line up; and a controller 60. The controller controls the relative displacement unit so that the relative displacement speed of the printing medium A and the light irradiation part is slower when the gap of the light irradiation part to the printing medium is a first gap compared to the case where the gap is a second gap smaller than the first gap.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] A known conventional printing device is the printing device disclosed in Patent Document 1. This printing device includes a head capable of ejecting liquid onto a recording medium and a light-emitting element capable of irradiating light onto the liquid ejected onto the printing medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-58670 Summary of the Invention [Problem to be solved by the invention]

[0004] The printing device of Patent Document 1 prints an image on a print medium by ejecting liquid from a head, causing it to land on the print medium, and then irradiating the print medium with light from light-emitting elements to fix the liquid to the print medium. In such a printing device, for example, if the print medium has a three-dimensional shape, the distance between the light-emitting elements and the print medium changes depending on the unevenness of the print medium, and the time from when the liquid lands on the print medium until the light is irradiated onto the liquid on the print medium changes. This can cause the appearance of the liquid cured by the light to become uneven, potentially resulting in a decrease in image quality.

[0005] In view of the above, an object of the present invention is to provide a printing device that can suppress deterioration in print quality caused by the shape of the printing medium. [Means for solving the problem]

[0006] A printing device according to one aspect of the present invention comprises a head that ejects liquid onto a printing medium, a light irradiation unit that irradiates light onto the liquid on the printing medium, a relative movement device that moves the printing medium relative to the head and the light irradiation unit in a movement direction in which the head and the light irradiation unit are aligned, and a control unit, wherein the control unit controls the relative movement device so that when the gap between the light irradiation unit and the printing medium is a first gap, the relative movement speed between the printing medium and the light irradiation unit is slower than when the gap is a second gap that is smaller than the first gap. [Effects of the Invention]

[0007] The present invention has an effect of providing a printing device that can suppress deterioration in print quality caused by the shape of the print medium.

[0008] The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a printing device. [Figure 2] FIG. 2 is a functional block diagram showing the configuration of the printing device of FIG. [Figure 3] FIG. 2 is a schematic diagram of the head unit of FIG. 1 as viewed from below. [Figure 4] 2 is a schematic diagram of the head unit and stage of FIG. 1 as viewed from the front. [Figure 5] Figure 5(a) is a graph showing the change over time in the illuminance of light in the second gap region, and Figure 5(b) is a graph showing the change over time in the illuminance of light in the first gap region. [Figure 6] Fig. 6(a) is a schematic diagram of a head unit and a printing medium having projections and depressions as viewed from the front, and Fig. 6(b) is a schematic diagram of a head unit and a printing medium having an inclination as viewed from the front. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding elements will be designated by the same reference numerals throughout the drawings, and redundant description thereof will be omitted.

[0011] (Embodiment) <Printing device configuration> As shown in FIG. 1 , a printing device 10 according to an embodiment of the present invention is, for example, an inkjet printer that prints an image by ejecting a liquid from a head 20 onto a printing medium A and irradiating the printing medium A with light from a light irradiation unit 30. Examples of the printing medium A include sheets of fabric and paper, as well as three-dimensional objects such as balls and mugs. The liquid is a photocurable liquid, such as ink that is cured by light such as ultraviolet or infrared light. Alternatively, the printing device 10 may be, for example, a 3D printer that creates a shaped object formed from ink ejected from the head 20 and cured by light irradiated from the light irradiation unit 30. In this case, the created shaped object is the printing medium A. Furthermore, the printing device 10 may print an image on the created shaped object by ejecting ink from the head 20 and irradiating the ink with light from the light irradiation unit 30. In this case, the created shaped object is the printing medium A.

[0012] The printing device 10 includes a head unit 11, a relative movement device 40, a transport device 50, a tank 12, and a control device 60 (FIG. 2). Details of the control device 60 will be described later. The movement direction in which the head 20 and the light irradiation unit 30 are aligned is referred to as the left-right direction, the transport direction that intersects (e.g., is perpendicular to) the movement direction is referred to as the front-rear direction, and the direction that intersects (e.g., is perpendicular to) the left-right direction and the front-rear direction is referred to as the up-down direction. However, the arrangement of the printing device 10 is not limited to this.

[0013] The relative movement device 40 has a pair of moving rails 41, a carriage 42, a drive belt 43, and a moving motor 44, and moves the head unit 11 in the left-right direction. The pair of moving rails 41 are elongated members extending in the left-right direction and are arranged parallel to each other in the front-to-back direction, sandwiching the head unit 11 between them. The carriage 42 carries the head unit 11 and is supported so as to be movable in the left-right direction along the moving rails 41. The drive belt 43 is an endless belt that extends in the left-right direction along the moving rails 41, is connected to the carriage 42, and is linked to the moving motor 44 via a pulley. The moving motor 44 drives the drive belt 43, causing the carriage 42 to reciprocate in the left-right direction along the moving rails 41. In this way, the relative movement device 40 moves the printing medium A, the head 20, and the light irradiation unit 30 relatively in the left-right direction.

[0014] The transport device 50 has a stage 51, transport rails 52, a stage support base 53, and a transport motor 54 (FIG. 2). The stage 51 has the print medium A placed on its upper surface, supports the print medium A, and defines a gap between the print medium A and the head 20 in the vertical direction. The transport rails 52 extend in the front-to-rear direction. The stage support base 53 supports the stage 51, for example, and is supported so as to be movable in the front-to-rear direction along the transport rails 52, and is connected to the transport motor 54. The transport motor 54 drives the stage support base 53, thereby moving the stage 51 in the front-to-rear direction.

[0015] The head unit 11 includes a head 20 and a light irradiation unit 30, and is arranged so that the bottom surfaces of these face the top surface of the stage 51. The tank 12 is a container that stores liquid, and is connected to the head 20 by a tube or the like to supply the liquid.

[0016] <Head unit configuration> 3 and 4, the head 20 has a plurality of nozzles 21, a liquid flow path, a flow path formation body 24, and a plurality of drive elements 25 (FIG. 2). The plurality of nozzles 21 are aligned at equal intervals in the front-to-rear direction to form a nozzle row 26. The plurality of nozzle rows 26 are aligned at equal intervals in the left-to-right direction.

[0017] The flow path forming body 24 has, for example, a rectangular parallelepiped shape, and has the nozzle 21 and liquid flow paths formed therein. The nozzle 21 opens at the bottom surface of the flow path forming body 24. The liquid flow paths are connected to the tank 12 ( FIG. 1 ) and the nozzle 21, and have a common flow path 23 and a plurality of individual flow paths 22. The common flow path 23 extends in the front-to-rear direction, and the plurality of individual flow paths 22 branch off from the common flow path 23. The upstream ends of the individual flow paths 22 are connected to the common flow path 23, and the downstream ends of the individual flow paths 22 are connected to the nozzle 21. Therefore, the liquid flows from the tank 12 to the common flow path 23, and while flowing in the front-to-rear direction in the common flow path 23, it is diverted into the individual flow paths 22 and supplied to the nozzle 21.

[0018] The driving elements 25 are piezoelectric elements, heat generating elements, electrostatic actuators, etc., and are provided corresponding to the individual flow paths 22, and drive the individual flow paths 22 to vary the volumes of the individual flow paths 22. This applies pressure to the liquid in the individual flow paths 22 to eject the liquid from the nozzles 21.

[0019] The light irradiation unit 30 is disposed upstream of the head 20 in the direction in which the head 20 moves while ejecting liquid. In unidirectional printing, for example, the head 20 ejects liquid when it moves to the left, and does not eject liquid when it moves to the right. In this case, the light irradiation unit 30 is disposed on the right side, which is upstream of the head 20 in the direction of movement to the left during printing. The light irradiation unit 30 irradiates light onto the liquid on the printing medium A while moving in tandem with the head 20, which ejects liquid onto the printing medium A.

[0020] In bidirectional printing, the printing device 10 has a pair of light irradiation units 30 arranged to sandwich the head 20 in the left-right direction. The right light irradiation unit 30 of the pair of light irradiation units 30 irradiates light onto the liquid on the printing medium A while moving leftward, following the head 20 which moves leftward to eject liquid onto the printing medium A. The left light irradiation unit 30 of the pair of light irradiation units 30 irradiates light onto the liquid on the printing medium A while moving rightward to follow the head 20 which moves rightward to eject liquid onto the printing medium A.

[0021] The light irradiation unit 30 has a plurality of light sources 31 and a circuit board 32 on which the light sources 31 are mounted. The circuit board 32 is made of, for example, an insulating material, has a rectangular flat plate shape, and has a bottom surface on which the light sources 31 are mounted. The light sources 31 are, for example, light-emitting elements such as LEDs, and are driven by the control device 60 to emit light (for example, ultraviolet or infrared light) that cures the liquid discharged from the nozzles 21.

[0022] The intensity of the light emitted by the light source 31 is the radiant flux emitted per unit time from a unit area of the light source 31, and is expressed as, for example, the radiant emittance (mW / cm 2 ) In contrast, the illuminance of light irradiated from the light source 31 on the printing medium A is the radiant flux per unit area of the printing medium A of the light incident from the light source 31 per unit time, for example, irradiance (mW / cm 2 ) The illuminance is expressed as irradiance (mW / cm 2 The integrated light amount may be the light energy per unit area (mJ / cm ) of the light irradiated from the light irradiation unit 30 on the printing medium A multiplied by the light irradiation time (s). 2 )

[0023] The multiple light sources 31 are lined up in the front-to-back direction to form a light source array 33. The multiple (e.g., seven) light source arrays 33 are lined up at intervals in the left-to-right direction. Each light source 31 radiates light of equal intensity onto the printing medium A.

[0024] <Control device configuration> As shown in FIG. 2, the control device 60 is connected to the drive element 25 via a head drive circuit 63 and controls the drive of the drive element 25. The control device 60 is connected to the light source 31 via a light source drive circuit 64 and controls the drive of the light source 31. The control device 60 is connected to the movement motor 44 via a movement drive circuit 65 and controls the drive of the movement motor 44. The control device 60 is connected to the conveyance motor 54 via a transport drive circuit 66 and controls the drive of the conveyance motor 54. In this way, the control device 60 controls the drive, stopping, rotation speed, etc. of the movement motor 44 and the conveyance motor 54. In this way, the relative movement speed between the stage 51, the printing medium A placed thereon, and the head unit 11 is controlled.

[0025] The control device 60 is connected to an external power source B, such as a commercial power source, via a power supply circuit 67. The power supply circuit 67 generates an output voltage from the DC voltage from the external power source B, and supplies power to each part of the printing device 10, such as the drive element 25, the light source 31, the movement motor 44, and the transport motor 54.

[0026] The control device 60 has a calculation unit 61 and a storage unit 62. The storage unit 62 is a memory accessible by the calculation unit 61 and is composed of RAM, ROM, etc. The RAM temporarily stores various data such as print data. The ROM stores programs for performing various data processing. The control device 60 may be a single control device 60 that performs centralized control, or multiple control devices 60 that perform distributed control. The program may also be stored in a storage medium other than the storage unit 62. Furthermore, the program may be stored in a single storage medium, or may be divided and stored across multiple storage media.

[0027] The calculation unit 61 is configured with a processor such as a CPU, an integrated circuit such as an ASIC, etc. The calculation unit 61 executes a program stored in the ROM to control the drive element 25, the light source 31, the movement motor 44, and the transport motor 54, and executes the printing process.

[0028] <Printing process> In such a printing device 10, the control device 60 acquires print data and executes printing processing based on the print data. The print data includes image data (e.g., raster data) that indicates an image to be printed on the printing medium A. The print data may be stored in the storage unit 62, or may be acquired from an external device such as a network, a computer, or a storage medium.

[0029] The control device 60 controls the movement motor 44 to perform a movement operation that moves the head unit 11 in the left-right direction. The control device 60 also controls the drive element 25 to perform a discharge operation that discharges liquid from the head 20. The control device 60 also controls the light source 31 to perform a light irradiation operation that irradiates light from the light source 31. The control device 60 also controls the transport motor 54 to perform a transport operation that transports the printing medium A forward. The printing device 10 then alternately repeats scanning, which includes the movement operation, discharge operation, and light irradiation operation, and the transport operation, to proceed with the printing process.

[0030] During this scan, as shown in Figure 4, head 20 moves to the left while ejecting liquid from head 20. As a result, the liquid lands on print medium A on stage 51, which faces the underside of head 20. In addition, light irradiation unit 30 moves to the left following head 20, while irradiating light from light source 31. As a result, light is irradiated onto the liquid on print medium A facing light source 31, and the liquid is hardened by the light and fixed to print medium A. As a result, an image is printed on print medium A using the liquid.

[0031] 4, the gap between the printing medium A and the light irradiation unit 30 varies in the left-right direction, with the gap being a first gap equal to or greater than a predetermined value G1 and a second gap being less than the predetermined value G1. Therefore, the printing medium A has a first gap region A1, which is the region of the first gap, and a second gap region A2, which is the region of the second gap.

[0032] In this case, light with an illuminance shown in FIG. 5(a) is irradiated from the light irradiating unit 30 onto the second gap region A2. Also, light with an illuminance shown in FIG. 5(b) is irradiated from the light irradiating unit 30 onto the first gap region A1. In this way, when the light irradiating unit 30 irradiates light downward toward the printing medium A, the light spreads in a direction perpendicular to the up-down direction as it moves downward away from the light irradiating unit 30. The illuminance (mW / cm) of the light on the printing medium A is 2 ) increases in the direction perpendicular to the up-down direction toward the center of the light irradiation unit 30 and decreases the further away from the center. The range on the printing medium A where this illuminance is equal to or greater than a predetermined curing illuminance is defined as the light irradiation range. The predetermined curing illuminance is, for example, the illuminance I0 that cures the liquid on the printing medium A.

[0033] This curing can be done in two stages: full curing and provisional curing. Proper curing is when the liquid has a higher viscosity than the uncured liquid immediately after impact, but is not completely cured, and the viscosity of the liquid has increased to the point where it does not flow on the printing medium A, specifically, the liquid is in a gel state. Full curing is when the liquid is completely cured, specifically, when the liquid does not stick to your hands when you touch it.

[0034] The range of light irradiation from the light irradiation unit 30 in the first gap region A1 shown in Figure 5(b) is wider than the range of light irradiation from the light irradiation unit 30 in the second gap region A2 shown in Figure 5(a). For this reason, for example, if Liquid J lands in the first gap region A1 and is cured by light before it spreads on the printing medium A, the cured product will have a matte appearance. On the other hand, for example, if Liquid J lands in the second gap region A2 and is cured by light after it spreads on the printing medium A, the cured product will have a glossy appearance.

[0035] In this way, if the curing time of the liquid J differs depending on the gap, the appearance of the cured product will be non-uniform, resulting in a decrease in print quality. In response to this, in the printing device 10, the control device 60 controls the relative movement device 40 so that when the gap of the light irradiation unit 30 relative to the printing medium A is the first gap, the relative movement speed between the stage 51 and the light irradiation unit 30 is slower than when the gap is the second gap, which is smaller than the first gap. This reduces the difference in curing time until the liquid J that has landed on the printing medium A cures, and reduces the degradation of image quality.

[0036] Specifically, the control device 60 divides the print data into scan print data for each scan. The control device 60 also obtains gap information indicating the gap between the print medium A and the light irradiation unit 30, for example, based on measurements by a sensor provided in the printing device 10 or specifications indicating the shape of the print medium A. The control device 60 then moves the head unit 11 to the left by a movement operation, ejects liquid J from the head 20 onto the print medium A by a discharge operation based on the scan print data, and irradiates light from the light irradiation unit 30 onto the liquid J on the print medium A by a light irradiation operation. During this movement operation, the control device 60 switches the movement speed of the light irradiation unit 30 of the head unit 11 between a first speed and a second speed based on the gap information.

[0037] 5(a), the illuminance of the light from the light irradiation unit 30 reaches the predetermined curing illuminance I0 at time ta0 after the liquid J lands from the head 20 at time t0, and the liquid J cures for a second curing time Ta0 during this time. Also, in the first gap area A1 in FIG. 5(b), the illuminance of the light reaches the predetermined curing illuminance I0 at time tb0 after the liquid J lands at time t0, and the liquid J cures for a first curing time Tb0 during this time.

[0038] The light irradiation range of the first light irradiation unit 30a in this first gap region is wider than the light irradiation range of the second light irradiation unit 30b in the second gap region, but the movement speed of the light irradiation unit 30 in the first gap region A1 is made slower than the movement speed of the light irradiation unit 30 in the second gap region A2. This makes the first curing time Tb0 equal to or approach the second curing time Ta0, reduces non-uniformity in the appearance of the cured product of the liquid J, and suppresses degradation of print image quality caused by the shape of the print medium A.

[0039] <Variation 1> In the printing device 10 according to the first modification, in the above embodiment, when printing is performed by alternately repeating scanning including a movement operation of moving the head 20 and the light irradiation unit 30 by the relative movement device 40, a discharge operation of discharging liquid from the head 20, and a light irradiation operation of irradiating light from the light irradiation unit 30, and a transport operation of transporting the printing medium A by the transport device 50, the control device 60 moves the head 20 and the light irradiation unit 30 at a first speed, and A first light irradiation operation for irradiating a gap region of the printing medium A with light, and a second light irradiation operation for irradiating a second gap region of the printing medium A with light while moving the head 20 and the light irradiation unit 30 at a second speed faster than the first speed, are performed in one scan, or the scan has a first scan including the first light irradiation operation but not the second light irradiation operation, and a second scan including the second light irradiation operation but not the first light irradiation operation, and the first scan and the second scan are performed separately between the transport operation and the transport operation following the transport operation.

[0040] Specifically, in one scan, the control device 60 moves the head unit 11 to the left by a movement operation, ejects the liquid J from the head 20 onto the printing medium A by a discharge operation based on the scan print data, and irradiates the liquid J on the printing medium A with light from the light irradiation unit 30 by a light irradiation operation. Here, the control device 60 switches the movement speed of the light irradiation unit 30 of the head unit 11 between a first speed and a second speed based on the gap information. In other words, the control device 60 moves the light irradiation unit 30 at the first speed in the first gap, and moves the light irradiation unit 30 at a second speed faster than the first speed in the second gap.

[0041] In the light irradiation range of the light irradiation unit 30 on the printing medium A due to this scanning light irradiation operation, the first gap region is wider than the second gap region. In contrast, the first speed of the light irradiation unit 30 irradiating the first gap region with light is slower than the second speed of the light irradiation unit 30 irradiating the second gap region with light. Therefore, the movement speed to the light irradiation range in the first gap region is slower than the movement speed to the light irradiation range in the second gap region. Therefore, the first curing time Tb0 of the liquid J by the light irradiation unit 30 in the first gap region matches or approaches the second curing time Ta0 of the liquid J by the light irradiation unit 30 in the second gap region, thereby reducing non-uniformity in the appearance of the cured product of the liquid J and suppressing degradation of print image quality due to the shape of the printing medium A.

[0042] The first light irradiation operation and the second light irradiation operation may be performed by separate scans. In this case, the control device 60 divides the print data into scan print data for each scan, and then divides this scan print data into first gap print data and second gap print data based on the gap information. Note that, although the following describes a case where the second scan is performed after the first scan, the first scan may also be performed after the second scan.

[0043] Then, the control device 60 performs a first scan, moving the head unit 11 at a first speed, while performing a discharge operation in the first gap based on the first gap print data and performing a first light irradiation operation. In this discharge operation, the control device 60 causes the head 20 to discharge liquid J into the first gap region A1 without discharging liquid from the head 20 into the second gap region A2 of the printing medium A. Furthermore, in the first light irradiation operation, the control device 60 causes the light irradiation unit 30 to irradiate light onto the first gap region A1. As a result, the illuminance of the light in the first gap region A1 reaches the curing illuminance I0 of the liquid J at the first curing time Tb0, and the liquid J on the first gap region A1 is cured and printed on the printing medium A.

[0044] Then, the control device 60 moves the head unit 11 to the right without performing a transport operation, and then performs a second scan. During this second scan, the control device 60 moves the head unit 11 to the left at a second speed within the print range of the first scan, while performing a discharge operation in the second gap based on the print data for the second gap and performing a second light irradiation operation. During this discharge operation, the control device 60 does not discharge liquid from the head 20 into the first gap region A1 of the print medium A, but instead discharges liquid J from the head 20 into the second gap region A2. Furthermore, during the second light irradiation operation, the control device 60 irradiates light onto the second gap region A2. As a result, the illuminance of light in the second gap region A2 reaches the curing illuminance I0 of the liquid J within the second curing time, and the liquid J in the second gap region A2 is cured and printed on the print medium A.

[0045] The first and second scans are performed between a transport operation and the transport operation following the transport operation. The first speed of the light irradiation unit 30 during the first light irradiation operation of the first scan is set slower than the second speed of the light irradiation unit 30 during the second light irradiation operation of the second scan. This makes the movement of the light irradiation range by the light irradiation unit 30 slower in the first gap than in the second gap, allowing the first curing time of the liquid J to match or approach the second curing time. This reduces non-uniformity in the appearance of the cured product of the liquid J and suppresses degradation of print image quality due to the shape of the print medium A.

[0046] <Variation 2> In the printing device 10 according to variant example 2, in variant example 1, the control device 60 performs the first light irradiation operation and the second light irradiation operation in one scan if the gap satisfies a specified condition, and performs the first scan and the second scan separately if the gap does not satisfy the specified condition.

[0047] Specifically, as shown in FIG. 6(a), the control device 60 acquires the length L1 of the first gap region A1 and the length L2 of the second gap region A2 in the left-right direction based on the gap information. If the print medium A has little or no inclination or few or no steps, and both lengths L1 and L2 are equal to or greater than a predetermined length, the number of times the speed of the light irradiation unit 30 is switched during each scan is small or non-existent. In this case, the control device 60 determines that the predetermined condition is met and performs the first light irradiation operation and the second light irradiation operation by changing the movement speed of the light irradiation unit 30 during one scan.

[0048] On the other hand, if the print medium A has a large incline or many steps, and at least one of the lengths L1 and L2 is shorter than the predetermined length, the speed of the light irradiation unit 30 must be changed in a short time during the scan. In this case, the control device 60 determines that the predetermined condition is not met and performs the first scan and the second scan separately. As a result, the control device 60 moves the light irradiation unit 30 at a first speed during the first light irradiation operation of the first scan, and moves the light irradiation unit 30 at a second speed during the second light irradiation operation of the second scan. This allows the print medium A to be printed in a manner appropriate to the shape of the print medium A without changing the movement speed of the light irradiation unit 30 during a single scan, thereby suppressing degradation of print quality due to the shape of the print medium A.

[0049] <Variation 3> In the printing device 10 according to the third modification, in the second modification, if the rate of change of the gap in the direction of movement is less than a predetermined rate, the gap satisfies the predetermined condition, and if the rate of change of the gap is equal to or greater than the predetermined rate, the gap does not satisfy the predetermined condition.

[0050] 6(b), there are multiple thresholds for the gap between the printing medium A and the light irradiation unit 30 (for example, a first predetermined value G1, which is the above-mentioned predetermined value G1, and a second predetermined value G2, which is smaller than the first predetermined value G1). In this case, the gap includes a first gap that is equal to or greater than the first predetermined value G1, a second gap that is less than the first predetermined value G1 and equal to or greater than the second predetermined value G2, and a third gap that is less than the second predetermined value G2. Therefore, the printing medium A has a first gap region A1, which is the region of the first gap, a second gap region A2, which is the region of the second gap, and a third gap region A3, which is the region of the third gap.

[0051] For example, the control device 60 acquires the gap change rate H / L, which is the change in gap length H in the up-down direction per unit length L in the left-right direction, based on the gap information. If the printing medium A has a large inclination, the gap change rate is equal to or greater than a predetermined rate. In this case, the distance between each gap area on the printing medium A in the left-right direction is short, and the speed of the light irradiation unit 30 moving over the printing medium A must be changed in a short time. Therefore, the control device 60 determines that the predetermined condition is not met and performs the first scan, second scan, and third scan separately.

[0052] Therefore, the control device 60 divides the print data into scan print data for each scan, and further divides this scan print data into first gap print data, second gap print data, and third gap print data based on the gap information. Then, the control device 60 executes a first scan, and while moving the head unit 11 at a first speed, ejects liquid J from the head 20 into the first gap region A1 based on the first gap print data, and irradiates light from the light irradiation unit 30 onto the first gap region A1. As a result, the liquid J in the first gap region A1 is cured for a first curing time and printed on the print medium A.

[0053] Then, the control device 60 performs a second scan without performing a transport operation. During this second scan, the control device 60 ejects liquid J from the head 20 into the second gap region A2 based on the second gap print data while moving the head unit 11 at a second speed faster than the first speed over the print range of the first scan, and causes the light irradiation unit 30 to irradiate light onto the second gap region A2. As a result, the liquid J in the second gap region A2 hardens for a second hardening time and is printed on the print medium A.

[0054] Furthermore, the control device 60 performs a third scan without performing a transport operation. During this third scan, the control device 60 moves the head unit 11 over the printing range of the third scan at a third speed faster than the second speed, ejecting liquid J from the head 20 into the third gap region A3 based on the third gap print data, and irradiating light from the light irradiation unit 30 onto the third gap region A3. As a result, the liquid J in the third gap region A3 is cured for a third curing time and printed onto the printing medium A. In this way, by printing on the printing medium A in a manner that corresponds to the shape of the printing medium A without changing the movement speed of the light irradiation unit 30 during a single scan, it is possible to suppress degradation of print image quality due to the shape of the printing medium A.

[0055] On the other hand, if there is little or no tilt in the printing medium A, the gap change rate is less than a predetermined rate. In this case, the distance between each gap area in the printing medium A in the left-right direction is long, and the number of times the speed of the light irradiation unit 30 moving over the printing medium A in one scan is changed is small or nonexistent. Therefore, the control device 60 determines that the predetermined conditions are met and performs the first light irradiation operation, the second light irradiation operation, and the third light irradiation operation in one scan. As a result, the control device 60 moves the head unit 11 at a first speed in the first light irradiation operation, moves the head unit 11 at a second speed in the second light irradiation operation, and moves the head unit 11 at a third speed in the third light irradiation operation. In this way, the movement speed of the light irradiation unit 30 is changed in one scan. In this way, by printing the printing medium A in a manner appropriate to the shape of the printing medium A, it is possible to suppress degradation of print quality caused by the shape of the printing medium A.

[0056] <Variation 4> In the printing device 10 according to variant 4, in variants 1 to 3, when the control device 60 performs the first scan and the second scan separately, and performs the second scan before performing the first scan, the control device 60 irradiates light onto the first gap area in addition to the second gap area during the first scan.

[0057] Specifically, in the second scan, the control device 60 causes the head 20 of the head unit 11, which is moving at the second speed, to eject liquid J into the second gap region A2, and then irradiates light onto the second gap region A2 from the light irradiation unit 30. Then, without transporting the printing medium A, the control device 60 moves the head unit 11 to the right, and then performs the first scan.

[0058] Here, the control device 60 causes the head 20 of the head unit 11 moving at a first speed to eject the liquid J into the first gap region A1, and then causes the light irradiation unit 30 to irradiate the first gap region A1 and the second gap region A2 with light. As a result, the light is irradiated onto the liquid J in the first gap region A1 and the liquid J in the second gap region A2, causing the liquid J to harden. At this time, although the illuminance of the light in the first gap region A1 is lower than that in the second gap region A2, the liquid J in the first gap region A1 is irradiated with light during both the first scan and the second scan, and therefore the liquid J in the first gap region A1 can be sufficiently hardened.

[0059] <Other variations> In all of the above embodiments and modifications, the relative movement device 40 moves the head 20 in the left-right direction relative to the printing medium A without moving the printing medium A. In contrast, the relative movement device 40 may move the stage 51 in the left-right direction so as to move the printing medium A relative to the head 20 without moving the head 20.

[0060] For example, when the relative movement device 40 moves the stage 51, the relative movement device 40 may include a transport device 50. In this case, the carriage 42 carries the stage 51, and the stage support base 53 supports the moving rail 41. This allows the stage 51 to move left and right along the moving rail 41, and the moving rail 41 to move in the front and rear directions. Therefore, the stage 51 moves left and right and front and rear directions relative to the head unit 12.

[0061] In all of the above embodiments and variants, for example, when the printing medium A is tilted in the left-right direction, the control device 60 may control the relative movement device 40 so that the relative movement speed between the printing medium A and the light irradiation unit 30 becomes continuously slower as the gap between the printing medium A and the light irradiation unit 30 becomes larger.

[0062] It should be noted that all of the above embodiments may be combined with one another as long as they do not exclude one another. Furthermore, many improvements and other embodiments of the present invention will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present invention. Details of the structure and / or function of the present invention may be substantially changed without departing from the spirit of the present invention. [Industrial Applicability]

[0063] The printing device according to the present invention is useful as a printing device that can suppress deterioration in print quality due to the shape of the print medium. [Explanation of symbols]

[0064] 10:Printing device 20: Head 30: Light irradiation unit 40: Relative movement device 50:Transportation device 60: Control device

Claims

1. a head that ejects liquid onto a printing medium; a light irradiation unit that irradiates the liquid on the printing medium with light; a relative movement device that moves the print medium, the head, and the light irradiation unit relatively in a movement direction in which the head and the light irradiation unit are aligned; a control device; When the gap of the light irradiation unit with respect to the printing medium is a first gap, the control device controls the relative movement device so that the relative movement speed between the printing medium and the light irradiation unit until the light irradiation range, where the illuminance of light irradiated from the light irradiation unit is a predetermined value, reaches the impact point of the liquid on the printing medium, is slower than when the gap is a second gap smaller than the first gap, so that a first curing time from when the liquid impacts the first gap until the light irradiation range reaches the impact point matches a second curing time from when the liquid impacts the first gap until the light irradiation range reaches the impact point.

2. a transport device that transports the print medium in a transport direction that intersects with the movement direction; The control device When printing is performed by alternately repeating scanning including a movement operation of moving the head and the light irradiation unit by the relative movement device, a discharge operation of discharging the liquid from the head, and a light irradiation operation of irradiating the light from the light irradiation unit, and a transport operation of transporting the printing medium by the transport device, Depending on the uneven shape of the printing medium, a first light irradiation operation in which the light is irradiated onto a first gap region of the printing medium, the gap being the first gap, while moving the head and the light irradiation unit at a first speed, and a second light irradiation operation in which the light is irradiated onto a second gap region of the printing medium, the gap being the second gap, while moving the head and the light irradiation unit at a second speed faster than the first speed, in one scan; or 2. The printing device according to claim 1, wherein the scanning includes a first scanning including the first light irradiation operation but not the second light irradiation operation, and a second scanning including the second light irradiation operation but not the first light irradiation operation, and the first scanning and the second scanning are performed separately between the transport operation and the transport operation subsequent to the transport operation.

3. The control device When the gap satisfies a predetermined condition, the first light irradiation operation and the second light irradiation operation are performed in one scan; The printing apparatus according to claim 2 , wherein if the gap does not satisfy the predetermined condition, the first scan and the second scan are performed separately.

4. If the rate of change of the gap in the movement direction is less than a predetermined rate, the gap satisfies the predetermined condition; 4. The printing device according to claim 3, wherein the gap does not satisfy the predetermined condition when the rate of change of the gap is equal to or greater than the predetermined rate.

5. A printing device according to any one of claims 2 to 4, wherein the control device performs the first scan and the second scan separately, and when the control device performs the second scan and then the first scan, the control device irradiates the light onto the first gap area in addition to the second gap area during the first scan.

6. a stage for supporting the print medium; The printing apparatus according to any one of claims 1 to 5, wherein the relative movement device moves the stage.

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