Liquid discharge device

Abstract

To provide a liquid discharge device which can improve image quality while securing fastness of an image, and which has suppressed cost required in image formation, in DTF printing.SOLUTION: A liquid discharge device includes: a first discharge part for discharging ink to a base material; a second discharge part for discharging a liquid-like binder which is for thermal transfer with respect to the base material to which the ink has been discharged; and a control part. The control part determines a use amount of ink per unit area on the basis of image information, and controls the second discharge part in such a manner that a discharge amount of the binder per unit area in the case where the determined use amount of the ink is lower than a predetermined reference value is made to be larger than the discharge amount of the binder per unit area in the case where the determined use amount of the ink is greater than or equal to the predetermined reference value.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] DTF (Digital to Film or Direct to Film) printers are known as image forming devices. DTF printers apply coloring ink to a substrate such as a film, apply a heat-soluble adhesive powder to the printing surface, and transfer the coloring ink on the film to a recording medium such as clothing.

[0003] Conventional DTF printers had problems with uneven application of adhesive powder. Also, when using adhesive powder, the adhesive powder did not adhere to areas with a low amount of ink, so a large amount of clear ink was applied to make the adhesive powder adhere. Applying a large amount of clear ink caused problems such as bleeding at color boundaries and beading, as well as increased costs.

[0004] Patent Document 1 discloses that a colored layer and an adhesive layer are formed on a substrate. According to Patent Document 1, it is possible to improve visibility while facilitating production. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the robustness of the image in Patent Document 1 is insufficient, and there is a demand for achieving both cost reduction and sufficient robustness. There is also a demand for improving image quality by suppressing color boundary bleeding and beading.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a liquid ejection apparatus that can improve image quality while ensuring image robustness in DTF printing, and that reduces costs required for image formation. [Means for solving the problem]

[0007] In order to solve the above problems, the liquid ejection device of the present invention has a first ejection section that ejects ink onto a substrate, a second ejection section that ejects a liquid binder for thermal transfer onto the substrate onto which the ink has been ejected, and a control section, wherein the control section determines an amount of ink usage per unit area based on image information, and controls the second ejection section so that the amount of binder ejected per unit area when the determined amount of ink usage is lower than a predetermined reference value is greater than the amount of binder ejected per unit area when the determined amount of ink usage is equal to or greater than the predetermined reference value. Effect of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection device that can improve image quality while ensuring image robustness in DTF printing and reduce costs required for image formation. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view illustrating an example of a liquid ejection device. [Diagram 2] FIG. 1 is a diagram illustrating a configuration of an example of a liquid ejection device. [Diagram 3] FIG. 2 is a block diagram showing a hardware configuration of an example of a liquid ejection device. [Figure 4] 5A and 5B are diagrams illustrating a configuration of a heater in an example of a liquid ejection device. [Diagram 5] FIG. 4 is a schematic plan view illustrating an example of a discharge section. [Figure 6] 1 shows an example of a dot pattern of a binder, where (A) is a random pattern in Example 1, and (B) is a honeycomb-structured dot pattern in Example 2. [Figure 7] 1 is a diagram showing an example of the relationship between the color ink adhesion amount, the powder application amount, and the special color ink adhesion amount, where (A) and (B) are comparative examples, and (C) is Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The liquid ejection device according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and may be modified, added, modified, deleted, or otherwise altered within the scope of what a person skilled in the art can conceive, and any embodiment is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0011] The liquid ejection device of the present invention has a first ejection section that ejects ink onto a substrate, a second ejection section that ejects a liquid binder for thermal transfer onto the substrate onto which the ink has been ejected, and a control section, wherein the control section determines an amount of ink usage per unit area based on image information, and controls the second ejection section so that the amount of binder ejected per unit area when the determined amount of ink usage is lower than a predetermined reference value is greater than the amount of binder ejected per unit area when the determined amount of ink usage is equal to or greater than the predetermined reference value.

[0012] According to the present invention, in DTF printing, image quality can be improved while ensuring image robustness, and costs required for image formation can be reduced.

[0013] Fig. 1 is a perspective view of a liquid ejection device 1 according to this embodiment. Fig. 2 is a diagram showing the configuration of the liquid ejection device 1 according to this embodiment. As shown in Figs. 1 and 2, the liquid ejection device 1 according to this embodiment includes a device main body 10 and a support base 11 that supports the device main body 10.

[0014] Side plates 10A and 10B are provided on the left and right sides of the device body 10. A guide rod 12 and a guide stay 13, which are guide members, are hung between the side plates 10A and 10B. The liquid ejection device 1 also includes a sub-metal guide 14. The guide rod 12 and the guide stay 13 hold a carriage 15 so that it can slide freely.

[0015] The main scanning mechanism 16 that moves and scans the carriage 15 includes a main scanning motor 17 disposed on one side in the main scanning direction, a drive pulley 18 that is rotationally driven by the main scanning motor 17, a driven pulley 19 disposed on the other side in the main scanning direction, and a timing belt 20 that is a pulling member that is wound around between the drive pulley 18 and the driven pulley 19. Note that tension is applied to the driven pulley 19 outward (in the direction away from the drive pulley 18) by a tension spring.

[0016] The carriage 15 moves in the direction of arrow A (main scanning direction) via a timing belt 20 that is rotationally driven by a main scanning motor 17. The carriage 15 also includes an optical sensor 21 that detects the edge of the medium (paper edge).

[0017] The carriage 15 is equipped with a liquid ejection head 23 that ejects ink droplets of each color, such as black (K), yellow (Y), magenta (M), cyan (C), etc., and binder, etc., according to the attached ink cartridge 22.

[0018] The liquid ejection head 23 of this example is an example of a liquid ejection section, and includes ejection sections 23a, 23b, and 23c. The ejection sections 23a, 23b, and 23c each have a nozzle row, and the nozzle row is arranged in the direction of arrow B (sub-scanning direction). Here, the sub-scanning direction is a direction perpendicular to the main scanning direction. The liquid ejection head 23 is mounted so that the droplet ejection direction from the ejection sections 23a, 23b, and 23c faces downward.

[0019] The ejection sections 23a, 23b, and 23c of the liquid ejection head 23 are grounded, for example, so as to be shifted from one another in the sub-scanning direction. The carriage 15 is equipped with sub-tanks to supply inks of different colors and binders to the liquid ejection head 23. In addition, white ink, clear ink, etc. may be supplied.

[0020] The liquid ejection device 1 includes a cartridge loading section 2 in which ink cartridges 22a, 22b, 22c, and 22d of each color are detachably mounted. The ink in the ink cartridges 22 is replenished and supplied to a sub-tank of the carriage 15 via a supply tube 24 of each color by a supply pump unit. The ink cartridges 22 include binder ink cartridges, and may include white ink cartridges, etc.

[0021] The liquid ejection device 1 includes a maintenance and recovery mechanism 3 in a non-printing region on one side in the main scanning direction of the carriage 15. The maintenance and recovery mechanism 3 maintains or recovers the states of the ejection portions 23a, 23b, and 23c of the liquid ejection head 23.

[0022] The maintenance and recovery mechanism 3 includes a cap 31 for capping each nozzle surface of the liquid ejection head 23, and a wiping unit 32 for wiping the nozzle surface. In addition, a replaceable waste liquid tank is provided below the maintenance and recovery mechanism 3 for storing waste liquid generated by the maintenance and recovery operation.

[0023] Paper 41 is set in paper feed means 40, but paper 41 of different width sizes can also be set.

[0024] Fig. 3 is a block diagram showing a hardware configuration of the liquid ejection device 1 according to this embodiment. As shown in Fig. 3, the liquid ejection device 1 includes a control unit 100, an operation panel 120, a sensor 130, a head driver 140, a main scanning motor 17, a sub-scanning motor 150, a carriage 15, a conveyor belt 160, a printer driver 170, a fan 180, and a heater 190.

[0025] The control unit 100 includes a central processing unit (CPU) 101, a read only memory (ROM) 102, and a random access memory (RAM) 103.

[0026] The CPU 101 performs overall control of the liquid ejection device 1. The ROM 102 stores fixed data such as programs executed by the CPU 101. The RAM 103 temporarily stores image data and the like.

[0027] The control unit 100 includes a non-volatile RAM (NVRAM) 104 and an application specific integrated circuit (ASIC) 105.

[0028] The NVRAM 104 is a non-volatile memory that retains data even when power is cut off from the liquid ejection device 1. The ASIC 105 processes various types of signal processing for image data, image processing such as sorting, and other input / output signals for controlling the entire liquid ejection device 1.

[0029] The control unit 100 has a print control unit 106. The carriage 15 transfers data for driving the liquid ejection head 23 to a head driver 140. The head driver 140 drives the liquid ejection head 23 provided on the carriage 15, and causes the liquid ejection head 23 to eject ink.

[0030] The control unit 100 has a motor driving unit 107. The motor driving unit 107 drives a main scanning motor 17 and a sub-scanning motor 150. The main scanning motor 17 is driven to move and scan the carriage 15. The sub-scanning motor 150 is driven to move the conveyor belt 160 in a circular motion.

[0031] The control unit 100 has an I / O 108. The I / O 108 acquires information from a sensor 130 and extracts information used for controlling each part of the main body of the liquid ejection device 1. For example, the sensor 130 corresponds to a group of sensors such as a photosensor, a temperature sensor, and an encoder sensor. The operation panel 120 inputs and outputs various types of information.

[0032] The control unit 100 has a host I / F 109. The host I / F 109 transmits and receives data and signals to and from the host side. Specifically, data and signals are transmitted and received from the printer driver 170 side of the host, such as an information processing device such as a client PC, an image reading device, or an image capturing device, via a cable or a network. The CPU 101 reads and analyzes the print data in the receiving buffer included in the host I / F 109. Then, the ASIC 105 performs image processing, data sorting processing, and the like, and the image data is transferred from the print control unit 106 to the head driver 140.

[0033] The print control unit 106 transfers the image data as serial data, and outputs a transfer clock, latch signal, control signal, and the like required for transferring the image data to the head driver 140. The head driver 140 selectively provides a drive pulse constituting a drive waveform provided by the print control unit 106 to the pressure generating means of the liquid ejection head 23 based on image data corresponding to one line of the liquid ejection head 23, which is input serially. This drives the liquid ejection head 23 to eject liquid.

[0034] By selecting some or all of the pulses that make up the drive waveform, and some or all of the waveform elements that form the pulses, it is possible to print dots of different sizes, such as large droplets, medium droplets, and small droplets.

[0035] The control unit 100 has a fan control unit 110 and a heater control unit 111. The fan control unit 110 controls the output of the fan 180 so that air is blown at a predetermined temperature and volume. The heater control unit 111 controls the heater 190 so that the temperature is set to a preset value.

[0036] When driven, the fan 180 promotes air convection inside the liquid ejection device 1 and prevents an excessive temperature rise due to stagnation of heated air at the upper part of the liquid ejection device 1. The fan 180 is connected to a fan control unit 110 of the control unit 100.

[0037] Fig. 4 is a diagram showing the configuration of a heater 190 of the liquid ejection device 1 according to this embodiment. For simplicity, in the example shown in Fig. 4, the illustration of some of the liquid ejection heads 23 is omitted.

[0038] 4, the heater 190 includes a pre-heater 190a, a print heater 190b, a print heater 190c, a post-heater 190d, and a drying heater 190e. Each of these heaters 190 is provided with a temperature sensor such as a thermistor for temperature control.

[0039] The preheater 190a is a device that preheats the medium P to a temperature suitable for forming a liquid application surface. For example, the preheater 190a is an aluminum foil cord heater. The preheater 190a is attached to the back surface of the transport guide plate 191. The preheater 190a warms the medium P by heating the transport guide plate 191 itself.

[0040] The print heaters 190b and 190c are devices that keep the medium P warm when forming a liquid application surface on the medium P. For example, the print heaters 190b and 190c are cord heaters embedded in a platen 192 made of aluminum. The print heaters 190b and 190c warm the medium P by heating the platen 192 itself.

[0041] The post heater 190d and the drying heater 190e are devices that warm the medium P on which a liquid-coated surface has been formed in order to dry and fix the liquid, such as ink. For example, the post heater 190d is an aluminum foil cord heater. The post heater 190d is affixed to the rear surface of the transport guide plate 191. The post heater 190d warms the medium P by heating the transport guide plate 191 itself. Also, for example, the drying heater 190e is an IR heater. The drying heater 190e dries the liquid-coated surface of the medium P by emitting IR radiation to the liquid-coated surface of the medium P. The drying heater 190e may be configured to include a fan and blow hot air to the liquid-coated surface of the medium P.

[0042] Next, an example of the operation of the liquid ejection device 1 according to this embodiment will be described.

[0043] The CPU 101 reads and analyzes the print data in the receiving buffer of the host I / F 109 , performs necessary image processing, data sorting processing, etc. in the ASIC 105 , and transfers the data to the print control unit 106 .

[0044] The print control unit 106 outputs image data and drive waveforms at required timing to the head driver 140. In detail, the print control unit 106 generates a drive waveform consisting of one drive pulse or multiple drive pulses by D / A converting and amplifying the drive pulse pattern data stored in the ROM 102 and read by the CPU 101.

[0045] In addition, image data for image output may be generated by, for example, storing font data in ROM 102, or the image data may be expanded into a bitmap by a printer driver on the host side and transferred to the liquid ejection device 1.

[0046] The head driver 140 selectively applies drive pulses constituting a drive waveform provided by the print control unit 106 to the pressure generating means of the liquid ejection head 23 based on the input image data, thereby driving the liquid ejection head 23.

[0047] The heater 190 turns on when waking up from sleep mode, and is controlled to a set temperature according to the medium P and mode. When the heater 190 starts up, the liquid ejection device 1 is in a state in which a liquid coated surface can be formed, and starts the initial operation for forming the liquid coated surface. The drying heater 190e starts to turn on when formation of the liquid coated surface starts.

[0048] The medium P is set on the preheater 190a side. The medium P is transported in the direction of arrow B by a transport belt 160 to which a driving force is applied from a sub-scanning motor 150, and a liquid-coated surface is formed by the ejection of liquid from the liquid ejection head 23. For example, the medium P may be, in addition to roll-type paper, soft packaging media such as PET, PVC, OPP, and sheet-like media.

[0049] The medium P sent from the preheater 190a side is first preheated by the preheater 190a to a temperature suitable for forming a liquid application surface. The preheated medium P is sent by the conveyor belt 160 to the image forming section 193 in which the liquid ejection head 23 is arranged.

[0050] In the image forming section 193, the medium P is kept warm by print heaters 190b and 190c, while liquid such as ink is ejected onto the medium P from the liquid ejection head 23 to form a liquid-coated surface. The heated air rises together with the steam, but to prevent the temperature of the upper part of the liquid ejection device 1 from excessively increasing due to the accumulation of the air, the fan 180 promotes air convection.

[0051] An image is formed by transporting the medium P in the sub-scanning direction and scanning the carriage 15 in a direction perpendicular to the direction of movement of the medium P. When forming an image, the number of scans can be changed according to the resolution of the image to be created, making it possible to form a high-resolution image.

[0052] The medium P on which the liquid-coated surface has been formed in the image forming section 193 is sent further downstream.

[0053] The drying heater 190e preheats the filament to a target temperature before the medium P with the liquid-coated surface arrives. After that, when the medium P with the liquid-coated surface arrives, the drying heater 190e turns on in synchronization with the timing of stopping the sub-scanning. The timing of turning on the heater can be changed depending on the type and mode of the medium P.

[0054] The post heater 190d and the drying heater 190e that blows hot air dry and fix the liquid such as ink on the medium P. After drying and fixing, the medium P is further wound up into a roll downstream.

[0055] Next, a detailed example of the liquid ejection apparatus according to this embodiment will be described. In a typical DTF (Direct to Film) process, an adhesive powder is applied to the printed surface of an inked substrate and dried to create a transfer substrate, after which the image on the transfer substrate is thermally transferred to a recording medium. However, when adhesive powder is used as in the past, the particle size of the components contained in the adhesive powder is about 200 to 300 μm, and the particles are not perfectly round, so gaps and uneven adhesion inevitably occur. In addition, since the adhesive powder reacts with the moisture contained in the ink and adheres to it, the adhesive powder does not adhere easily to areas where the amount of ink adhered is small. In areas where the adhesive powder is not adhered to, the image is not transferred. For this reason, in the past, in areas where the amount of ink adhered is small, it was necessary to unnecessarily increase the amount of ink by using special color inks such as white ink, light ink, and clear ink. In this case, color boundary bleeding and beading may occur, resulting in a decrease in image quality.

[0056] In response to this, the present invention is as follows. The liquid ejection device of the present invention has a first ejection section that ejects ink onto a substrate, a second ejection section that ejects a liquid binder for thermal transfer onto the substrate onto which the ink has been ejected, and a control section, wherein the control section determines the amount of ink usage per unit area based on image information and controls the second ejection section so that the amount of binder ejected per unit area when the determined amount of ink usage is lower than a predetermined reference value is greater than the amount of binder ejected per unit area when the determined amount of ink usage is equal to or greater than the predetermined reference value.

[0057] The liquid binder may be referred to as a liquid glue or the like. In the following description, the liquid binder may be simply referred to as a binder. In addition, when it is described that the binder is ejected, it means that the liquid binder is ejected. The ink usage amount may be referred to as the ink adhesion amount, etc. The binder ejection amount may be referred to as the binder application amount, binder application amount, etc. In the following description, the ink usage amount per unit area may be simply referred to as the ink usage amount. Also, the binder ejection amount per unit area may be simply referred to as the binder ejection amount.

[0058] The following provides additional information regarding the amount of ink used and the amount of binder ejected. The control unit 100 determines the amount of ink used per unit area based on the image information. The amount of ink used per unit area is the average or total amount of ink used for each pixel included in the unit area. The amount of ink used can also be said to be an amount that indicates how much ink is ejected in the area of ​​the unit area. The control unit 100 adjusts the binder ejection amount based on the determined ink usage amount. If the determined ink usage amount is lower than a predetermined reference value, the control unit 100 controls to increase the binder ejection amount in that region. Specifically, for example, the second ejection unit is controlled so that the binder ejection amount per unit area is greater than a predetermined reference value. The binder ejection amount can also be said to be an amount indicating how much binder is ejected into a unit area region. If the determined ink usage amount is equal to or greater than a predetermined reference value, the control unit 100 controls to decrease the binder ejection amount in that region. Specifically, for example, the control unit 100 controls the second ejection unit so that the binder ejection amount per unit area is smaller than a predetermined reference value. In one image, there are multiple unit areas for which the amount of ink used is determined, so the control unit increases the amount of binder ejected in areas where ink usage is low, and decreases the amount of binder ejected in areas where ink usage is high.

[0059] In this embodiment, in DTF printing, a liquid binder is ejected onto a substrate. By using a liquid binder, there is no need to increase the amount of special color ink in areas where ink usage is low. This makes it possible to reduce costs by the amount that would have been incurred by increasing the amount of special color ink. Furthermore, in this embodiment, there is no need to unnecessarily increase the amount of special color ink in areas where ink usage is low, and it is possible to suppress bleeding and beading at color boundaries. This makes it possible to prevent degradation of image quality and improve image quality.

[0060] On the other hand, if the film formed by the ink and binder is thin, fastness such as washing fastness may decrease. Therefore, in this embodiment, the ink usage amount is determined, and the binder ejection amount is adjusted according to the determined ink usage amount. In areas where the ink usage amount is low, the binder ejection amount is increased, for example, above a predetermined reference value, thereby ensuring fastness. Also, in areas where the ink usage amount is high, the binder ejection amount is reduced, for example, below a predetermined reference value, which leads to cost reduction.

[0061] The predetermined reference value to be compared with the ink usage amount determined by the control unit is not particularly limited and can be selected appropriately. The predetermined reference value can be changed depending on the type of ink, the type of base material, the type of binder, etc. The predetermined reference value when discharging the binder is not particularly limited and can be appropriately selected. The predetermined reference value can be changed depending on the type of ink, the type of base material, the type of binder, etc.

[0062] When a liquid binder is used, it can be applied to the substrate by discharging, and the dot pattern can be adjusted. The second discharge section preferably discharges the binder in a regular pattern. By discharging the binder in a regular pattern, the binder can be applied uniformly, and bias of the binder can be reduced. Therefore, deterioration of the image quality of the obtained image can be prevented, and the image quality can be improved.

[0063] As described above, in this embodiment, the ink usage amount is determined for each region (each region that is a unit area), and the binder ejection amount is adjusted for each region. Therefore, when the binder is ejected in a regular pattern, the ejection pattern is regular, but the binder ejection amount in that ejection pattern is adjusted for each region.

[0064] Fig. 5 is a schematic plan view for explaining a configuration example of the liquid ejection head 23, and is a plan view illustrating the nozzle surface of the ejection section. Fig. 5 shows two configuration examples, (A) and (B). In the example shown in Fig. 5(A), the ejection section 23a has nozzles 25K, 25M, 25C, and 25Y that eject color inks. The ejection section 23b has nozzle 25W that ejects white ink. The ejection section 23c has nozzle 25B that ejects a binder.

[0065] The liquid ejection device 1 of this embodiment has a first ejection section that ejects ink onto a substrate, and a second ejection section that ejects a binder. For example, the ejection section 23a can be the first ejection section, and the ejection section 23c can be the second ejection section. Also, the ejection section 23b can be the third ejection section, etc. However, such naming can be changed as appropriate.

[0066] In the illustrated example, the nozzles 25W are arranged in four nozzle rows, and the nozzles 25B are arranged in four nozzle rows, but this is not limited to this and can be changed as appropriate. The arrangement of the ejection sections 23a, 23b, and 23c is also not limited to the illustrated example and can be changed as appropriate.

[0067] Although the third ejection unit ejects white ink, the present invention is not limited to this, and light ink, clear ink, etc. may be ejected. As described above, white ink, light ink, clear ink, etc. may be referred to as special color ink, etc.

[0068] 5B, the ejection unit 23a and the ejection unit 23b have nozzles 25K, 25M, 25C, and 25Y that eject color inks. The ejection unit 23c has a nozzle 25B that ejects a binder. Such a configuration example is also included in this embodiment.

[0069] The ink ejected by the first ejection unit is a color ink containing a coloring material. Examples of the color ink include black, magenta, cyan, and yellow. The present embodiment is not limited to this, and may be a single color ink. The coloring material is not particularly limited, and any known coloring material may be used.

[0070] The binder discharged by the second discharge unit may or may not contain a coloring material. When the binder does not contain a coloring material and is transparent, it has an advantage that the desired image can be easily obtained. When the binder contains a coloring material, it has an advantage that the color of the obtained image can be adjusted.

[0071] The binder used in the present invention is a binder for thermal transfer. The binder may be called an adhesive liquid, an adhesive, a liquid glue, a binder liquid, etc. The binder used in the present invention may be a known binder used in DTF printing.

[0072] The substrate in this embodiment is a transfer substrate for thermally transferring an image to a recording medium. As the substrate, a known substrate used in DTF printing can be used. As the substrate, for example, a vinyl chloride resin film, a polyethylene terephthalate (PET) film, a plastic film such as polypropylene, polyethylene, or a polycarbonate film can be used.

[0073] An image to be transferred is formed on the substrate by discharging ink onto the substrate and then discharging a binder onto the substrate. The binder layer formed on the substrate is then brought into contact with a recording medium for thermal transfer. This results in the formation of an image on the recording medium. As the recording medium, cloth can be suitably used. Examples of cloth include cloth for clothing such as T-shirts. As the recording medium, paper and the like can be used in addition to cloth.

[0074] As described above, the second discharge unit preferably discharges the binder in a regular pattern. The discharge pattern can be appropriately selected. The second discharge unit preferably discharges the binder in a dot arrangement, for example, consisting of a triangle, a square, or a hexagon, as a discharge pattern. In this case, the binder can be applied uniformly, and robustness can be ensured. In addition, the amount of binder used can be prevented from becoming excessive, and the amount of binder used can be reduced, which also leads to cost reduction.

[0075] Fig. 6 is a diagram for explaining an example of a binder ejection pattern. The binder ejection pattern may be called a dot pattern or the like. Fig. 6(A) shows Example 1 in which the binder is ejected in a random pattern. Fig. 6(B) shows Example 2 in which the binder is ejected in a regular pattern.

[0076] In the case of Example 1, since the binder is difficult to apply uniformly, an acceptable level of fastness is obtained, but the image strength is biased. In the case of Example 2, the binder is applied uniformly, which prevents the image strength from being biased, and good fastness is obtained.

[0077] Moreover, Example 2 is an example of a case where the binder is discharged in a dot arrangement formed by hexagons, and such a discharge pattern may be called a honeycomb structure dot pattern. In the case of Example 2, the binder can be applied uniformly, and bias of the binder can be reduced. In Example 2, a pattern structure with high strength is obtained, and robustness can be ensured, and deterioration of the image quality of the obtained image can be prevented. In addition, in the case of such a honeycomb structure dot pattern, there are areas where the binder is not discharged, which allows the amount of binder used to be reduced, thereby reducing costs.

[0078] 7 is a diagram for explaining an example of the relationship between the color ink adhesion amount, the powder application amount, the special color ink adhesion amount, and the liquid glue application amount. The horizontal axis is gradation (%), and the vertical axis is adhesion amount (%). The color ink deposition amount is the amount of ink used as described above. The powder application amount may be referred to as the amount of adhesive powder applied, and refers to the amount of powder binder applied. The spot color ink deposition amount is an indicator similar to the ink usage amount. The liquid glue application amount is the amount of binder ejected as described above. These values ​​are amounts per unit area.

[0079] (A) is a diagram showing a conventional example, which is an example in which spot color ink is not used. As the number of gradations increases, the amount of color ink used must be increased, and so the value of the color ink deposition amount on the vertical axis increases as the number of gradations increases. In this conventional example, the amount of powder (adhesive powder) used increases in line with the amount of color ink deposited. For this reason, as shown in the figure, the color ink deposition amount and powder application amount on the vertical axis increase in tandem as the number of gradations increases.

[0080] As described above, the powder adheres to, for example, the moisture in the ink. Therefore, in the case of the conventional example shown in (A), in areas where the amount of color ink attached is low, the powder does not adhere and there are areas where transfer does not occur. This causes transfer failure and significantly deteriorates the image formed on the recording medium.

[0081] (B) is a diagram showing another conventional example, which is an example in which a special color ink is used. As shown in the figure, where the amount of color ink adhesion is low, the amount of special color ink adhesion is high. Therefore, where the amount of color ink adhesion is low, the powder adheres to the moisture in the special color ink, making it possible to suppress transfer defects. Also, where the amount of color ink adhesion is high, there is no need to increase the amount of special color ink, so the amount of special color ink adhesion is low. The conventional example shown in (B) is able to suppress transfer defects more effectively than the conventional example shown in (A).

[0082] However, in the case of the conventional example shown in (B), the special color ink is applied unnecessarily to adhere the powder, which causes color boundary bleeding and beading, resulting in a decrease in image quality. In addition, the amount of special color ink used increases, resulting in increased costs.

[0083] (C) is a diagram showing Example 3 included in the present invention, which is an example in which a liquid binder (liquid glue) is used. As shown in the figure, in this example, the amount of liquid glue applied (binder discharge amount) is adjusted to be high in areas where the amount of color ink attached is low. This makes it possible to ensure fastness such as washing fastness. On the other hand, in areas where the amount of color ink attached is high, the amount of liquid glue applied is reduced. This makes it possible to reduce the amount of binder used. In this example, special color ink is not used unnecessarily, which makes it possible to prevent color boundary bleeding and beading and reduce costs.

[0084] For example, aspects of the present invention are as follows. <1> a first ejection unit that ejects ink onto a substrate; a second ejection unit that ejects a liquid binder for thermal transfer onto the base material onto which the ink has been ejected; A control unit, The control unit determines an amount of ink used per unit area based on image information, and controls the second ejection unit so that the amount of binder ejected per unit area when the determined amount of ink used is lower than a predetermined reference value is greater than the amount of binder ejected per unit area when the determined amount of ink used is equal to or greater than the predetermined reference value. A liquid ejection device comprising: <2> The second discharge unit discharges the binder in a regular pattern. Characterized by <1> The liquid ejection device according to claim 1 . <3> The second discharge unit discharges the binder in a dot arrangement formed of a triangle, a square, or a hexagon as the pattern. Characterized by <2> The liquid ejection device according to claim 1 . <4> The substrate is a transfer substrate for thermally transferring an image to a recording medium. Characterized by <1> from <3> 2. The liquid ejection apparatus according to claim 1 , [Explanation of symbols]

[0085] 23 Liquid ejection head 23a, 23b, 23c discharge part 25K, 25M, 25C, 25Y, 25B, 25W nozzles [Prior art documents] [Patent documents]

[0086] [Patent Document 1] JP 2021-183418 A

Claims

1. a first ejection unit that ejects ink onto a substrate; a second ejection unit that ejects a liquid binder for thermal transfer onto the base material onto which the ink has been ejected; A control unit, The control unit determines an amount of ink used per unit area based on image information, and controls the second ejection unit so that the amount of binder ejected per unit area when the determined amount of ink used is lower than a predetermined reference value is greater than the amount of binder ejected per unit area when the determined amount of ink used is equal to or greater than the predetermined reference value. A liquid ejection device comprising:

2. The second discharge unit discharges the binder in a regular pattern. The liquid ejection device according to claim 1 .

3. The second discharge unit discharges the binder in a dot arrangement formed of a triangle, a square, or a hexagon as the pattern. The liquid ejection device according to claim 2 .

4. The substrate is a transfer substrate for thermally transferring an image to a recording medium. The liquid ejection device according to claim 1 .

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