Ink discharge device and ink discharge method

Abstract

To provide an ink discharge device that can keep a depth of permeation of ink to a printed object constant, and stabilize an image quality and robustness, so that a stable quality can be obtained.SOLUTION: The ink discharge device comprises a discharge part 11 that discharges ink and liquid 14 existing in a direction in which the discharge part discharges the ink. The liquid can retain the ink discharged from the discharge part in the liquid or on a surface of the liquid. The ink retained by the liquid is made to adhere to a printed matter 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ink ejection device and an ink ejection method. [Background technology]

[0002] 2. Description of the Related Art Image forming apparatuses such as inkjet printers that are equipped with a head that ejects recording liquid such as ink and perform inkjet recording have been known.

[0003] In recent years, there has been an increasing demand for forming images on clothing such as T-shirts. Conventionally, inkjet recording has been performed by applying a pretreatment liquid to the T-shirt, heating and pressing it, drying it, and then performing inkjet recording. When using a pretreatment liquid, problems such as unevenness in the dots and image distortion have been pointed out.

[0004] In response to this, Patent Document 1 discloses an image forming apparatus in which a pretreatment liquid is applied to an intermediate transfer body, ink is supplied to the intermediate transfer body, and the ink supplied to the intermediate transfer body is transferred to a print substrate (also referred to as a recording medium, etc.). Patent Document 1 also discloses that the pretreatment liquid applied to the intermediate transfer body is heated. Patent Document 1 claims that it is possible to improve image transferability to a recording medium. Summary of the Invention [Problem to be solved by the invention]

[0005] When ink is supplied to an intermediate transfer body coated with a pretreatment liquid and the supplied ink is transferred to a printed material, the degree to which the ink penetrates into the recording medium changes depending on the amount of pretreatment liquid applied and drying conditions. This causes variations in image quality and image robustness. However, conventional techniques have not been able to control the degree to which the ink penetrates into a printed material such as a T-shirt. Therefore, there is a demand for a technology that can make the penetration depth of the ink into the printed material constant, stabilize image quality and robustness, and obtain stable quality.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an ink ejection device that can maintain a constant penetration depth of ink into a substrate, stabilize image quality and robustness, and obtain stable quality. [Means for solving the problem]

[0007] In order to solve the above problems, the ink ejection device of the present invention comprises an ejection section that ejects ink, and a liquid that exists in the direction in which the ejection section ejects the ink, and the liquid is capable of retaining the ink ejected from the ejection section within the liquid or on the surface of the liquid, and is characterized in that the ink retained in the liquid is adhered to a substrate to be printed. Effect of the Invention

[0008] According to the present invention, it is possible to provide an ink ejection device that can make the penetration depth of ink into a substrate constant, stabilize image quality and robustness, and obtain stable quality. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of an ink ejection device of the present invention. [Diagram 2] 1A to 1C are schematic cross-sectional or side views illustrating an example of an ink ejection device of the present invention, and a schematic plan view (a) of (A) and a schematic plan view (c) of (C). [Diagram 3] FIG. 2 is a diagram showing an example of a flow according to the present invention. [Figure 4] 1A and 1B are schematic cross-sectional or side views for explaining an example of an ink ejection device of the present invention. (a) is a printed matter obtained by (A). (C) is a schematic cross-sectional or side view for explaining a comparative example, and (c) is a printed matter obtained by (C). [Diagram 5] 5A to 5C are schematic cross-sectional or side views illustrating another example of an ink ejection device of the present invention. [Figure 6]FIG. 11 is a schematic cross-sectional view illustrating another example of an ink ejection device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The ink ejection device and the ink ejection method 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 within the scope of what a person skilled in the art can imagine, such as other embodiments, additions, modifications, deletions, etc., and any aspect is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0011] The ink ejection device of the present invention comprises an ejection section that ejects ink, and a liquid that exists in the direction in which the ejection section ejects the ink, and the liquid is capable of retaining the ink ejected from the ejection section within the liquid or on the surface of the liquid, and is characterized in that the ink retained in the liquid is adhered to a substrate to be printed.

[0012] The ink ejection method of the present invention comprises an ejection step in which an ejection section ejects ink into a liquid present in the direction of ejecting the ink, and an attachment step in which the ink is attached to a substrate, wherein the liquid is capable of retaining the ink ejected from the ejection section within the liquid or on the surface of the liquid, and the attachment step is characterized in that the ink retained in the liquid is attached to the substrate.

[0013] In the present invention, the ink is held in a liquid before being applied to a substrate (also referred to as a recording medium, etc.), and the ink held in the liquid is then applied to the substrate, thereby making it possible to make the penetration depth of the ink into the substrate constant. This makes it possible to stabilize image quality and robustness, and to obtain stable quality. In addition, in the present invention, since the penetration depth of the ink into the substrate can be controlled, it is possible to achieve both image quality and robustness, such as OD (optical density) and hiding rate.

[0014] Conventionally, in a DTG (Direct to Garment or Digital to Garment) printer that ejects ink directly onto a substrate such as a T-shirt to form an image, the resulting image has significant unevenness due to the surface condition of the substrate, such as the weave of the fibers. In the conventional technology, a pretreatment liquid is applied to the surface of the substrate in advance to aggregate the ejected ink and keep it as close to the surface as possible. However, since it is affected by the surface condition of the substrate, the penetration depth of the ink varies, and the image quality deteriorates due to deep penetration, or the robustness decreases due to shallow penetration. In the present invention, the penetration depth of the ink in the substrate can be made constant by attaching the ink held in a liquid to the substrate.

[0015] Another embodiment of the ink ejection device of the present invention comprises an ejection section that ejects ink and a liquid that exists in the direction in which the ejection section ejects the ink, and is characterized in that the ejection section ejects the ink onto the substrate while the substrate is immersed in the liquid and the surface of the substrate is exposed above the liquid level.

[0016] Another embodiment of the ink ejection method of the present invention includes an ejection step in which an ejection section ejects ink into a liquid present in a direction in which the ink is ejected, and the ejection step is characterized in that the ink is ejected onto the substrate while the substrate is immersed in the liquid and the surface of the substrate is exposed above the liquid surface.

[0017] In another embodiment of the present invention, the ink that has landed on the printed material permeates the recording medium and is held at or near the liquid surface of the liquid on the recording medium, or in the liquid, making it possible to make the penetration depth of the ink in the recording medium constant, thereby stabilizing image quality and robustness and enabling quality to be maintained.

[0018] The ink ejection device may be a liquid ejection device, an image forming device, an inkjet recording device, a printing device, etc. The ink ejection method may be a liquid ejection method, an image forming method, an inkjet recording method, a printing method, etc. The ink ejection device and the ink ejection method of the present invention are also applicable to DTG printers. Furthermore, the liquid capable of holding ink may be referred to as a holding liquid, etc. In the following description, unless otherwise specified, when the term liquid is referred to, it means a liquid capable of holding ink. Furthermore, the printed material and the recording medium are both synonymous. In the following description, the term recording medium will be used.

[0019] (First embodiment) An embodiment of the present invention will now be described. FIG. 1 is a schematic cross-sectional view illustrating an ink ejection device according to the present embodiment. The ink discharge device 1 includes a guide rod 12 supported by a main body frame 15. The ink discharge device 1 includes a carriage 10, and the carriage 10 is fitted around the guide rod 12.

[0020] The carriage 10 has a head 11. The head 11 is an example of an ejection unit, and ejects ink. The carriage 10 may also be called an ejection unit. The head 11 may also be called a liquid ejection head, a recording head, an inkjet recording head, or the like. The carriage 10 may have a single head 11 or multiple heads 11.

[0021] The head 11 reciprocates in the direction of the arrow in the figure, for example, and ejects ink downward. A liquid 14 capable of holding ink is provided in the direction in which the head 11 ejects ink. The liquid 14 is stored in a water tank 13.

[0022] As the carriage 10 reciprocates, it ejects ink toward the liquid surface of the liquid 14 located below. After the ink is ejected, an attachment process is performed in which the ink is attached to a recording medium (a substrate to be printed), thereby forming an image on the recording medium.

[0023] The liquid 14 in this example contains a component (agglomerating agent) that causes the ink to aggregate. The ink used in this example has a lower specific gravity than the liquid 14. In this case, the ejected ink tends to remain floating on the surface of the liquid 14. After the ejected ink in this example reaches the surface of the liquid 14, it becomes almost spherical and remains covered with a thin resin film. For example, in the liquid, each ink droplet floats independently.

[0024] The liquid preferably contains a flocculant. In this case, the ink is less likely to move after it hits the liquid, and the ink can have a constant penetration depth in the recording medium, resulting in stable image quality and robustness. The flocculant is a component that causes the ink to aggregate.

[0025] It is preferable that the liquid has a higher specific gravity than the ink, in which case the ink tends to remain floating in the liquid after it hits the liquid, and the ink can penetrate a constant depth into the recording medium, resulting in stable image quality and robustness.

[0026] From the viewpoint of retaining the ink, it is more preferable that the liquid has a higher specific gravity than the ink and has the effect of aggregating the ink. There are no particular limitations on the measurement of the specific gravity of the liquid and the ink as long as the temperature and measurement conditions are the same.

[0027] The components of the liquid are not particularly limited and can be appropriately selected depending on the purpose. The liquid may contain organic solvents, water, coagulants, resins, surfactants, defoamers, pH adjusters, antiseptics and fungicides, rust inhibitors, deodorizers, etc.

[0028] As the liquid 14, various liquids used in general image forming apparatuses, such as a pre-treatment liquid, a post-treatment liquid, a binder with an adhesive function, a coating liquid for protecting an image, a deodorant with a deodorizing function, etc. may be used. The pre-treatment liquid may be called an undercoat liquid, etc. The post-treatment liquid may be called an overcoat liquid, etc.

[0029] The pretreatment liquid contains a flocculant, an organic solvent, and water, and may contain, as necessary, a surfactant, an antifoaming agent, a pH adjuster, an antiseptic / fungal agent, an antirust agent, and the like. The organic solvent, surfactant, defoamer, pH adjuster, antiseptic / fungal agent, and rust inhibitor may be the same as those used in ink, and other materials used in known treatment liquids may be used. The type of the flocculant is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, and polyvalent metal salts.

[0030] The post-treatment liquid is obtained by selecting and mixing, as necessary, organic solvents, water, resins, surfactants, defoamers, pH adjusters, antiseptics, antifungals, rust inhibitors, etc. If the post-treatment liquid is transparent, it is less likely to affect the image.

[0031] 2 and 4, the liquid 14 adheres to the recording medium before the ink adheres to the recording medium, so the liquid 14 can also be used as a pre-treatment liquid. In the example shown in Fig. 5, the ink may adhere to the recording medium before the liquid 14 adheres to the recording medium, so the liquid 14 can also be used as a post-treatment liquid.

[0032] The inks used will be described in detail in the following embodiment.

[0033] 2 is a schematic diagram for explaining the process from ejection of ink to transfer of the ink to a recording medium. FIG. 2 is a diagram for explaining the area A in FIG.

[0034] 1A is a schematic cross-sectional view or a schematic plan view for explaining an example of a discharge step in this embodiment. 1A shows a state in which ink 18 is discharged from head 11 and the discharged ink 18 floats on the surface of liquid 14. The arrow in the figure shows a schematic scanning direction of carriage 10. As shown in the figure, ink 18 is discharged from head 11 and is held in liquid 14. The ink 18 is held in liquid 14 in the arrangement of an image to be formed.

[0035] (a) is a schematic plan view of (A) seen from above, and is a diagram showing a schematic state during the ink ejection process. As shown in the figure, ink 18 is held in the liquid 14 in the arrangement of the image to be formed. The arrows in the figure show the schematic scanning direction of the carriage 10. Reference numeral 10a shows another example of the arrangement of the carriage 10, and indicates that the carriage 10 scans back and forth.

[0036] 1B is a schematic cross-sectional view or a schematic plan view showing a state in which the carriage 10 has made several reciprocating movements and has completed the ejection of ink. The ink floating on the surface of the liquid 14 has coagulated and is in a state of increased viscosity. After the ejection of ink is completed, the table 17 rises vertically upward (arrow in the figure). A recording medium 20 is placed on the table 17. The table 17 is placed on, for example, an elevating mechanism 16, and can be moved up and down by the elevating mechanism 16.

[0037] In the ejection step in this example, an ejection unit (e.g., head 11) ejects ink 18 into liquid 14 that exists in the direction in which the ink is ejected. The liquid 14 is capable of retaining the ink 18 ejected from the ejection unit in the liquid 14 or on the surface of the liquid 14. In addition, in the ejection step in this example, the ink 18 is ejected in a state in which the surface of the recording medium 20 is not exposed from the liquid surface of the liquid 14.

[0038] Also, (B) explains the adhesion process in this example. In the adhesion process in this example, the table 17 is raised to cause the ink 18 held in the liquid 14 to adhere to the recording medium. As described above, "adhere" may also be referred to as "transfer" or the like.

[0039] (C) is a schematic cross-sectional view or a schematic plan view showing the state after the table 17 has been raised. The figure shows the state in which the table 17 has been raised to a position where the recording medium 20 appears above the liquid surface of the liquid 14. The ink, which has become viscous and has taken on a spherical shape, is transferred onto the recording medium, for example while floating on the liquid surface. When transferred, the spherical shape is broken and the ink penetrates into the recording medium. The recording medium is then removed and heated or pressed as necessary, so that the ink is fixed onto the recording medium.

[0040] 1C is a schematic plan view of 1C as viewed from above. When the table 17 rises, the ink 18 is placed on the recording medium 20. As a result, the ink 18 is transferred to the recording medium 20.

[0041] According to this embodiment, by holding the ink in liquid before applying it to the recording medium, it is possible to make the penetration depth of the ink into the recording medium constant when applying the ink to the recording medium. In this embodiment, since the ink can be kept adhered to the vicinity of the surface of the recording medium, it is possible to make the penetration depth of the ink into the recording medium constant by applying the ink held in liquid to the recording medium. Therefore, the image quality and robustness of the obtained printout are stable, and quality can be maintained.

[0042] The phrase "adhering the ink held in the liquid to the recording medium" may also be referred to as "transferring the ink held in the liquid to the recording medium." The adhering process may also be referred to as a transfer process. The process from ejecting the ink to transferring the ink to the recording medium may also be referred to as image formation or the like. Image formation may also be referred to as printing, recording, printing, or the like, and may include a process of fixing the ink.

[0043] The table 17 is an example of a support portion. The support portion will be further described. The ink ejection device of this example includes a support section on which a recording medium can be placed, and the support section is movable up and down in the vertical direction. After the ejection section ejects ink, the ink ejection device of this example moves the support section upward with the recording medium placed on the support section, thereby causing the ink held in the liquid to adhere to the recording medium. By using the support portion, the recording medium can be moved stably, and the ink can be applied stably to the recording medium.

[0044] The support part can be appropriately selected. The support part preferably has a liquid-permeable material. Examples of the liquid-permeable material include a sponge and a base material with a net structure (such as a mesh).

[0045] When the support part is raised to apply ink to the recording medium, generally, a recording medium such as a T-shirt is permeable to liquid. On the other hand, if the support part is made of a material that does not allow liquid to pass through, a flow of liquid occurs along the surface of the support part, and the ink held in the liquid may flow. If the support part has a liquid-permeable material, the liquid can flow when the support part moves, such as rising, and the ink held in the liquid can be made less likely to move. Therefore, the ink held in the liquid can be well applied to the recording medium. However, if the ink held in the liquid is in a state where it is difficult to move even when the liquid flows, the material of the support portion may be an ordinary solid.

[0046] Fig. 3 is a flow chart for explaining an example of the procedure of image formation in this embodiment, which illustrates the example shown in Fig. 2 as a flow chart.

[0047] Before ink ejection, the interior of the device is filled with liquid 14 (S1). The liquid 14 is stored in, for example, a water tank 13. The recording medium 20 is set on the table 17 (S2). The table 17 is lowered to a position where the recording medium 20 is immersed in the liquid (S3). The carriage 10 is scanned to eject ink (S4). After ink ejection is complete (S5), the table 17 is raised and the ink 18 is transferred to the recording medium 20 (S6). This completes image formation (S7).

[0048] In this embodiment, the penetration depth of the ink transferred to the recording medium can be kept constant, and the variation in the penetration depth of the ink can be suppressed, thereby making it possible to stably maintain image quality and image robustness.

[0049] The variation in ink referred to here refers to the variation in the penetration depth of the ink due to, for example, the following differences. Examples include differences due to differences in temperature and humidity during image formation, and differences due to the surface properties (such as the degree of fiber fluffing) caused by the storage conditions of the recording medium. Other examples include differences in the type of recording medium. For example, differences in the type of T-shirt can be mentioned. A polyester T-shirt and a cotton T-shirt have different fiber thickness, density, and fiber weave, and when the same ink is ejected, the penetration depth and the spread of the dots can differ.

[0050] In this embodiment, even if there are differences as described above, it is possible to control the penetration depth of the ink and suppress variations in the penetration depth of the ink. Therefore, by controlling the height of the liquid surface, the height of the recording medium, and the distance between the liquid surface and the printing surface of the recording medium, it is possible to make the penetration depth of the ink into the recording medium constant. This stabilizes the image quality and robustness, and makes it possible to maintain the quality of the obtained image. Furthermore, in this embodiment, it is possible to suppress variations in the penetration depth of the ink each time image formation is performed, and it is possible to stabilize the quality of the image.

[0051] The state where the recording medium is immersed in the liquid may mean that the recording medium is completely immersed in the liquid, or that the recording medium is partially immersed in the liquid. When the recording medium is completely immersed in the liquid, the surface of the recording medium is not exposed above the liquid surface. In the example shown in Fig. 2, the ink 18 is ejected in a state where the surface of the recording medium 20 is not exposed above the liquid surface of the liquid 14.

[0052] The above example will be described again. In this example, the recording medium is placed in the liquid, and the ejection unit ejects the ink while the recording medium is immersed in the liquid and the surface of the recording medium is not exposed above the liquid surface. When the recording medium is below the liquid surface, the ink remains near the surface of the recording medium after transfer, and good image quality can be obtained.

[0053] On the other hand, when a part of the recording medium is immersed in the liquid, the surface of the recording medium is exposed above the liquid surface. In this case, the recording medium is placed in the liquid, and the ejection unit ejects the ink in a state in which the recording medium is immersed in the liquid and the surface of the recording medium is exposed above the liquid surface. For example, in the case of a recording medium that is thick, such as a T-shirt, the image robustness is increased if the ink penetrates the recording medium to a certain extent. Therefore, in this example, the image robustness can be improved. This example will be explained with reference to Figure 4.

[0054] Fig. 4 is a schematic cross-sectional view or a schematic plan view for explaining an example of controlling the height of table 17 when ink 18 is ejected. Fig. 4 is also a view for explaining an example of an ejection process. In this embodiment, the height of table 17 when ink is ejected can be appropriately selected. By controlling the height of table 17 when ink 18 is ejected, the penetration depth of ink 18 can be controlled.

[0055] 1A is an example of a case where ink 18 is ejected with table 17 in a low position. When table 17 is in a low position and deep in liquid 14, recording medium 20 is completely submerged in liquid 14. When ink 18 is ejected in this state, ink 18 lands on liquid 14 and floats on liquid 14. When table 17 is then raised, ink 18 rests on the surface of recording medium 20, and ink 18 is transferred to recording medium 20 in this manner.

[0056] 1(a) is a diagram for explaining the state after the ink 18 has been transferred to the recording medium 20 in the example shown in (A). As shown in the figure, the ink 18 is placed on the surface of the recording medium 20.

[0057] (B) is an example in which the position of the table 17 is higher than in the example of (A). In this example, the recording medium 20 is partially submerged in the liquid 14, and the ink 18 is ejected in this state. When the ink 18 is ejected in this state, the ink 18 penetrates the recording medium 20 and soaks up to the liquid surface of the liquid 14 in the recording medium 20. After the ink 18 is transferred to the recording medium 20, the ink 18 is positioned at a certain height inside the recording medium 20. Note that in the example shown in (B), the ink 18 is transferred to the recording medium 20 by raising the table 17 after the ink 18 is ejected.

[0058] 1(b) is a diagram for explaining the state after the ink 18 has been transferred to the recording medium 20 in the example shown in 1(B). As shown in the figure, when the ink 18 is transferred to the recording medium 20, the ink 18 is positioned at a certain height inside the recording medium 20. In this example, it can be said that the penetration of the ink 18 is shallow.

[0059] In the example shown in (B), it is preferable to keep the distance from the surface of the recording medium 20 to the liquid level of the liquid 14 constant. This makes it possible to stably maintain the penetration degree of the ink 18, and stably ensure both image quality and image robustness.

[0060] In the ejection process in (B), similar to the example shown in (A), an ejection unit that ejects ink (e.g., head 11) ejects ink 18 into liquid 14 that exists in the direction of ejecting the ink. In the ejection process in (B), the recording medium 20 is immersed in liquid 14, and ink 18 is ejected onto the recording medium 20 in a state in which the surface of the recording medium 20 is exposed above the liquid level of the liquid 14. This is different from the example shown in (A).

[0061] (C) is an example in which the position of table 17 is higher than in the example (B), and is a comparative example not included in the present invention. In this example, recording medium 20 is completely exposed above the surface of liquid 14, and recording medium 20 is not in contact with liquid 14. When ink 18 is ejected in this state, ink 18 penetrates deep into recording medium 20.

[0062] 1C is a diagram for explaining the state after the ink 18 has been transferred to the recording medium 20 in the example shown in 1C. As shown in the figure, when the ink 18 is transferred to the recording medium 20, the ink 18 is located at a height below the recording medium 20. In this example, it can also be said that the ink 18 has penetrated deeply.

[0063] Since different provisions can be made between the example shown in FIG. 2 and the example shown in FIG. 4(A) and the example shown in FIG. 4(B), they will be described again below. In the example shown in Figure 2 and the example shown in Figure 4 (A), the ink ejection device of this example places a recording medium in a liquid, and the ejection section ejects ink while the recording medium is immersed in the liquid and the surface of the recording medium is not exposed above the liquid surface. In the example shown in Figure 2 and Figure 4 (A), by retaining the ink in liquid before applying it to the recording medium, the penetration depth of the ink retained in the liquid can be made constant, and when the ink is applied to the recording medium, the penetration depth of the ink into the recording medium can be made constant.

[0064] 4B, the ink ejection device of this example includes an ejection unit that ejects ink, and a liquid that exists in the direction in which the ejection unit ejects the ink. The ejection unit of this example ejects ink onto the recording medium in a state in which the recording medium is immersed in the liquid and the surface of the recording medium is exposed above the liquid surface. 4B, the ink that has landed on and permeated the recording medium is held at or near the liquid surface of the recording medium, or in the liquid. This makes it possible to make the ink permeate a constant depth into the recording medium. For example, in the case of a recording medium such as a thick T-shirt, where the surface is uneven due to the weave of the fibers, being able to make the ink permeate a constant depth into the recording medium is an excellent advantage.

[0065] In the example shown in Fig. 4, the height of table 17 is controlled when ink is ejected, but it is not limited to the height of table 17, and the height of the liquid surface of liquid 14 may also be controlled. When controlling the height of table 17 or the height of the liquid surface of liquid 14, for example, the distance between head 11 and the surface on which the ink lands is controlled to be constant. The surface on which the ink lands here may be, for example, the surface of recording medium 20 or the liquid surface of liquid 14. To control the height of the liquid surface of liquid 14, for example, the amount of liquid 14 in water tank 13 may be changed.

[0066] The above will be explained again. The ink ejection device of this example is equipped with a control unit, and the control unit is capable of controlling at least one selected from the height of the liquid surface and the height of the substrate in the thickness direction of the substrate (recording medium) before the ejection unit ejects the ink. By doing so, the distance between the head 11 and the surface on which the ink lands can be made constant. In addition, the degree to which the recording medium is immersed in the liquid can be appropriately adjusted, making it easier to maintain quality. For example, by controlling the liquid level while the recording medium is immersed in the liquid, the penetration depth of the ink transferred to the recording medium can be kept constant even if the thickness of the recording medium varies. In addition, when image formation is repeated, the quality can be stabilized even if the amount of liquid in the water tank changes, making it easier to deal with image formation over time. Therefore, even over time, the penetration depth of the ink can be prevented from varying, and image quality and image robustness can be stably maintained.

[0067] Furthermore, the control unit may be configured to control the distance between the liquid surface and the surface of the recording medium to which the ink is to be adhered in the thickness direction of the recording medium, before the ejection unit ejects the ink.

[0068] An example of the control will be described. The ink ejection device of this example includes a sensor that detects the position of the liquid level and the position of the surface of the recording medium to which the ink is applied. For example, the surface of the recording medium to which the ink is applied (also called the printing surface) is used as a reference, and the position of the liquid level is adjusted so that the distance from the printing surface to the liquid level is a predetermined distance. For example, the position of the liquid level is controlled by adjusting whether to add or remove liquid so that the distance from the printing surface to the liquid level is X mm.

[0069] As a method for adjusting the position of the liquid level, for example, a supply mechanism that supplies the liquid from a tank that stores the liquid and a discharge mechanism that discharges the liquid from the water tank are used. The tank is provided separately from the water tank. The discharge mechanism may be called a drain mechanism or the like.

[0070] For example, let us consider a case where the distance from the reference printing surface to the liquid level is Y mm. If the sensor detects that the current liquid level is A mm lower than the printing surface, the supply mechanism supplies liquid to the tank, raising the liquid level by A+Y mm. On the other hand, if it is desired to lower the liquid level, for example if the current liquid level is B+Y mm, the discharge mechanism discharges liquid, lowering the liquid level by B mm.

[0071] When ejecting the ink, the distance between the liquid surface and the liquid surface of the recording medium can be appropriately selected. As explained above, the respective advantages are taken into consideration and the appropriate selection is made according to the purpose and printing conditions. In the case of Fig. 4(A), for example, the ink remains near the surface of the recording medium after transfer, improving image quality. In the case of Fig. 4(B), for example, when the recording medium is thick, the degree of ink penetration can be controlled and the ink can penetrate to a certain depth into the recording medium.

[0072] In addition to the above examples, the liquid level may be set to a position slightly above the surface of the recording medium. For example, when a T-shirt is used as the recording medium, the liquid level is set to a position slightly above the surface of the fibers. If ink is ejected in this state, the ink will not be completely on the surface of the T-shirt. This allows the ink to be transferred to the T-shirt with no variation in the degree of penetration.

[0073] An example of control will now be described in more detail. When ejecting ink, it is preferable to keep the distance between the head 11 and the surface on which the ink lands constant. There are no particular limitations on how to keep this distance constant, but for example, the following can be done. When the level of the liquid 14 is lower than the surface of the recording medium 20, the height of the liquid 14 is adjusted by changing the height of the liquid 14 without changing the height of the recording medium 20. On the other hand, when the level of the liquid 14 is higher than the surface of the recording medium 20 (when the recording medium 20 is submerged), the height of the liquid 14 is not changed, but the height of the recording medium 20 is adjusted by changing the height of the recording medium 20.

[0074] The recording medium is not particularly limited, but is preferably one that will not be damaged when wet with the liquid 14. Specific examples that can be used as appropriate include plain paper, glossy paper, special paper, film, OHP sheets, general-purpose printing paper, building materials such as walls, paper, flooring materials, tiles, and fabrics for clothing such as T-shirts, textiles, leather, and the like.

[0075] Specific examples of the film include plastic films, such as polyvinyl chloride resin film, polyethylene terephthalate (PET) film, polypropylene, polyethylene, and polycarbonate film, which are impermeable substrates. The non-permeable substrate is a substrate having a surface with low water permeability and absorbency, and includes materials that have many cavities inside but are not open to the outside. More quantitatively, in the Bristow method, 1 / 2 Water absorption up to 10mL / m 2 The term "substrate" refers to a substrate that is:

[0076] Moreover, by adjusting the configuration of the path along which the recording medium is transported, it is also possible to use ceramics, glass, metal, etc. The transport of the recording medium will also be described in the following embodiment, for example, in FIG.

[0077] The present embodiment will now be described in further detail below, with respect to the liquid holding the ink. The phrase "liquid holds ink" includes a state in which the ink remains on the surface of the liquid and floats, as well as a state in which the ink is located at a location where it has permeated from the surface of the liquid. In the examples shown in Fig. 2 and Fig. 4(A), the ink remains on the surface of the liquid or near the surface, or in the liquid, and such a state is preferable, but the present embodiment is not limited to this. For example, even if the ejected ink permeates the liquid and comes into contact with the recording medium, the ink can be transferred to the recording medium. This case is also included in the phrase "liquid holds ink."

[0078] There is no particular restriction as to where the ejected ink is located in the depth direction in the liquid. The ejected ink may be submerged in the liquid, or may be on the surface of the liquid. The ejected ink may exist only in the liquid, or a portion of the ink may protrude from the liquid, or may be on the surface of the liquid.

[0079] 4B, the case where the ejected ink lands on the recording medium, permeates the recording medium, and remains on or near the liquid surface of the liquid on the recording medium, or in the liquid, is also included in the liquid holding the ink. Therefore, the ejected ink may land on the liquid or on the recording medium. When the ejected ink lands on the recording medium, a part of the recording medium is immersed in the liquid, and the surface of the recording medium is exposed from the liquid.

[0080] It is preferable that ink droplets that land on the liquid have a thin film around them so that they do not mix with adjacent ink droplets. In this case, the ink droplets are more likely to exist as dots, improving image quality. However, this does not exclude cases where adjacent ink droplets mix with each other.

[0081] Second embodiment Next, another embodiment of the present invention will be described. In the above embodiment, ink is ejected with the recording medium positioned in the ink ejection direction, but the present invention is not limited to this. In the present invention, the recording medium does not have to be positioned in the ink ejection direction when ink is ejected. This embodiment will be described. Note that a description of matters similar to the above embodiment will be omitted.

[0082] In this embodiment, after the ink is ejected into the liquid, the substrate (recording medium) is placed on the liquid from the surface side thereof, and the ink held in the liquid is adhered to the substrate.

[0083] In a conventional printing process, a process was required in which a pretreatment liquid was applied to a recording medium, the pretreatment liquid was dried, and then ink was ejected onto the recording medium to print and then dried. On the other hand, in the case of this embodiment, if the liquid in which the recording medium is immersed is the pretreatment liquid, the process of applying the pretreatment liquid and the process of ejecting ink to print are carried out simultaneously, and only one drying step is required. As a result, the time required for operations such as applying and drying the pretreatment liquid can be reduced.

[0084] FIG. 5 is a schematic cross-sectional view or a schematic side view for explaining one example of this embodiment. 1A is a diagram showing a state in which ink 18 is being ejected toward a table 17 having liquid 14 on its surface. The ejected ink 18 floats on the surface of the liquid 14. As shown in the figure, no recording medium is placed on the table 17 when the ink 18 is ejected.

[0085] 1B is a diagram for explaining a schematic diagram of the operation of placing the recording medium 20 on the liquid 14 after the ejection of the ink 18 has been completed. In this manner, when the recording medium 20 is placed from the direction of the surface of the liquid 14, the state of the ink 18 floating on the liquid 14 is transferred as is to the recording medium 20. 1C is a diagram showing a schematic diagram of the state after the ink 18 has been transferred to the recording medium 20. In this manner, in this embodiment, the contact between the recording medium 20 and the liquid 14 can be limited to when the ink 18 is to be transferred to the recording medium 20.

[0086] (Third embodiment) Next, another embodiment of the present invention will be described, in which the same matters as those in the above embodiment will not be described.

[0087] Fig. 6 is a schematic cross-sectional view of the ink ejection device of this embodiment as viewed from the side. In the example shown in Fig. 1, water tank 13 is provided inside main body frame 15, but the present invention is not limited to this. As shown in the figure, main body frame 15 may be provided inside water tank 13.

[0088] Table 17 is movable up and down in the vertical direction, and also in the horizontal direction. In the drawing, the horizontal movement of table 17 is indicated typically by an arrow. Table 17 is movable, for example, in a direction perpendicular to the scanning direction of carriage 10, and transports recording medium 20 by moving in this direction. In the above embodiment, table 17 is referred to as a support section, but in the present invention table 17 may also be referred to as a transport section or the like.

[0089] In the figure, the control unit 22 is shown in a schematic manner. The control unit 22 is not particularly limited, but includes, for example, a CPU, a memory, etc. The control unit 22 controls, for example, the scanning of the carriage 10, the ejection of the head 11, and the elevation and movement of the table 17. In addition, as described above, the control unit 22 can control the distance between the printing surface of the recording medium 20 and the liquid surface of the liquid 14.

[0090] Although not particularly limited, the ink ejection device of this example has a tank 23, a discharge mechanism 24, and a sensor 25. The tank 23 stores the liquid 14 discharged from the water tank 13. The discharge mechanism 24 discharges the liquid 14 from the water tank 13. The sensor 25 detects the liquid level of the liquid 14, etc. Note that the liquid 14 discharged to the tank 23 may be supplied again to the water tank 13, or a supply tank may be provided separately from the tank 23, and the supply tank and the discharge tank may be separate.

[0091] (Fourth embodiment) The ink and the like used in the present invention will be described below, and a supplementary explanation of the above embodiment will be given.

[0092] <Ink> The ink used in the present invention is not particularly limited, but since the ink is held in the liquid after being ejected from the inkjet recording head, it is preferable that the ink has a specific gravity smaller than that of the liquid. The organic solvent, water, coloring material, resin, additives, etc. used in the ink will be described below.

[0093] <Organic solvent> The organic solvent used in the present invention is not particularly limited, and any water-soluble organic solvent can be used. Examples of the organic solvent include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.

[0094] Specific examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, and the like. polyhydric alcohols such as pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, and petriol, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether. polyhydric alcohol alkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone; amides such as formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine, and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol; propylene carbonate, and ethylene carbonate.

[0095] It is preferable to use an organic solvent having a boiling point of 250° C. or less, since this not only functions as a wetting agent but also provides good drying properties.

[0096] Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also suitably used. Specific examples of polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. Specific examples of the glycol ether compound include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; and polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0097] Polyol compounds having 8 or more carbon atoms and glycol ether compounds can improve the permeability of ink when paper is used as the recording medium.

[0098] The content of the organic solvent in the ink is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of the drying property and ejection reliability of the ink, however, the content is preferably from 10% by mass to 60% by mass, and more preferably from 20% by mass to 60% by mass.

[0099] <Water> The water content in the ink is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, however, it is preferably from 10% to 90% by mass, and more preferably from 20% to 60% by mass.

[0100] <Coloring material> The coloring material is not particularly limited, and pigments and dyes can be used. The pigment may be an inorganic pigment or an organic pigment. These may be used alone or in combination of two or more. Mixed crystals may also be used.

[0101] Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, and metallic pigments.

[0102] As inorganic pigments, titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, as well as carbon black produced by known methods such as the contact method, furnace method, and thermal method can be used.

[0103] As organic pigments, azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

[0104] Specific examples of pigments for black colors include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper, iron (CI Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (CI Pigment Black 1).

[0105] In addition, for color, CI Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, CI Pigment Yellow Range 5, 13, 16, 17, 36, 43, 51, CI Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88 , 101 (red oxide), 104, 105, 106, 108 (cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, CI Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38; CI Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63; CI Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.

[0106] The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. One type of dye may be used alone, or two or more types may be used in combination.

[0107] Examples of the dyes include CI Acid Yellow 17, 23, 42, 44, 79, 142, CI Acid Red 52, 80, 82, 249, 254, 289, CI Acid Blue 9, 45, 249, CI Acid Black 1, 2, 24, 94, CI Food Black 1, 2, CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, CI Direct Red 1, 4, 9, 80, 81, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, CI Directed Black 19, 38, 51, 71, 154, 168, 171, 195, and CI Reactive Red. 14, 32, 55, 79, 249, and CI Reactive Black 3, 4, and 35.

[0108] The content of the coloring material in the ink is preferably from 0.1% to 15% by mass, and more preferably from 1% to 10% by mass, from the viewpoints of improving image density, good fixing property and ejection stability.

[0109] Methods for dispersing a pigment to obtain an ink include a method of introducing a hydrophilic functional group into the pigment to make it a self-dispersing pigment, a method of dispersing the pigment by coating the surface of the pigment with a resin, and a method of dispersing the pigment using a dispersant.

[0110] As a method for introducing a hydrophilic functional group into a pigment to make it a self-dispersing pigment, for example, a method in which a functional group such as a sulfone group or a carboxyl group is added to a pigment (e.g., carbon) to make it dispersible in water can be mentioned.

[0111] As a method for dispersing a pigment by coating its surface with a resin, there is a method in which the pigment is encapsulated in a microcapsule to make it dispersible in water. This can be called a resin-coated pigment. In this case, it is not necessary for all of the pigments blended in the ink to be coated with a resin, and uncoated or partially coated pigments may be dispersed in the ink as long as the effect of the present invention is not impaired.

[0112] Examples of the method for dispersing using a dispersant include a method for dispersing using a known low molecular weight dispersant or a known polymeric dispersant, such as a surfactant.

[0113] As the dispersant, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. can be used depending on the pigment. RT-100 (nonionic surfactant) manufactured by Takemoto Oil Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used as dispersants. The dispersants may be used alone or in combination of two or more.

[0114] <Resin> The type of resin contained in the ink is not particularly limited and can be appropriately selected depending on the purpose. Examples of the resin include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Resin particles made of these resins may be used. The resin particles may be dispersed in water as a dispersion medium to form a resin emulsion, and then mixed with materials such as coloring materials and organic solvents to obtain an ink. The resin particles may be appropriately synthesized or may be commercially available. These may be used alone or in combination of two or more types of resin particles.

[0115] The volume average particle size of the resin particles is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of obtaining good fixing property and high image hardness, however, it is preferably from 10 nm to 1,000 nm, more preferably from 10 nm to 200 nm, and particularly preferably from 10 nm to 100 nm. The volume average particle size can be measured, for example, using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac-Bell Co., Ltd.).

[0116] The resin content is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of fixation property and storage stability of the ink, however, the resin content is preferably from 1% by mass to 30% by mass, and more preferably from 5% by mass to 20% by mass, of the total amount of the ink.

[0117] The particle size of the solid content in the ink is not particularly limited and can be appropriately selected depending on the purpose, but in terms of improving image quality such as ejection stability and image density, the maximum frequency in terms of maximum number is preferably 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles, pigment particles, etc. The particle size can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

[0118] <Additives> If necessary, surfactants, antifoaming agents, antiseptics, antifungals, rust inhibitors, pH adjusters, etc. may be added to the ink.

[0119] <Surfactant> As the surfactant, any of silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used.

[0120] Silicone surfactants are not particularly limited and can be appropriately selected according to purpose.Among them, those that do not decompose even at high pH are preferred, such as side chain modified polydimethylsiloxane, both end modified polydimethylsiloxane, one end modified polydimethylsiloxane, side chain both end modified polydimethylsiloxane, etc., and those having polyoxyethylene group or polyoxyethylene polyoxypropylene group as modified group are particularly preferred because they show good properties as aqueous surfactants.In addition, polyether modified silicone surfactants can also be used as the silicone surfactant, such as a compound in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylsiloxane.

[0121] As the fluorosurfactant, for example, perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups on the side chain are particularly preferred because they have low foaming properties. As the perfluoroalkyl sulfonic acid compounds, for example, perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, etc. are included. As the perfluoroalkyl carboxylic acid compounds, for example, perfluoroalkyl carboxylic acid, perfluoroalkyl carboxylate, etc. are included. As the polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups on the side chain, for example, sulfate ester salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups on the side chains, salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups on the side chains, etc. are included. As counter ions of the salts in these fluorosurfactants, Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, NH(CH2CH2OH)3, etc. are included.

[0122] Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.

[0123] Examples of nonionic surfactants include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and ethylene oxide adducts of acetylene alcohol.

[0124] Examples of the anionic surfactant include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and salts of polyoxyethylene alkyl ether sulfates. These may be used alone or in combination of two or more.

[0125] The silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the silicone surfactant include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and both-end side-chain modified polydimethylsiloxane. Polyether-modified silicone surfactants having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group are particularly preferred because they exhibit good properties as an aqueous surfactant.

[0126] Such surfactants may be appropriately synthesized or commercially available products, such as those available from BYK-Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.

[0127] The polyether-modified silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be a surfactant represented by the general formula (S-1) in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylpolysiloxane.

[0128] TIFF2025042895000002.tif45170 General formula (S-1)

[0129] (In the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)

[0130] As the polyether-modified silicone surfactant, commercially available products can be used, such as KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-1906EX (Nihon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Dow Corning Toray Silicone Co., Ltd.), BYK-33, BYK-387 (BYK-Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), and the like.

[0131] The fluorine-based surfactant is preferably a compound having 2 to 16 fluorine-substituted carbon atoms, and more preferably a compound having 4 to 16 fluorine-substituted carbon atoms.

[0132] Examples of fluorine-based surfactants include perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains, etc. Among these, polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains are preferred because they have low foaming properties, and fluorine-based surfactants represented by general formula (F-1) and general formula (F-2) are particularly preferred.

[0133] TIFF2025042895000003.tif14170 General formula (F-1)

[0134] In the compound represented by the above general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40 in order to impart water solubility.

[0135] General formula (F-2) C n F 2n+1 -CH2CH(OH)CH2-O-(CH2CH2O) a -Y

[0136] In the compound represented by the above general formula (F-2), Y is H or C m F 2m+1 m is an integer from 1 to 6, or CH2CH(OH)CH2-C m F 2m+1 m is an integer between 4 and 6, or C p H 2p+1 where p is an integer from 1 to 19. n is an integer from 1 to 6. a is an integer from 4 to 14.

[0137] As the fluorine-based surfactant, commercially available products may be used. Examples of such commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, and FC-431 (all manufactured by Sumitomo 3M Limited); Megafa F-470, F-1405, F-474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT- 250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by NEOS Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by OMNOVA Co., Ltd.), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), and the like. Among these, FS-3100, FS-34, FS-300 manufactured by Chemours Co., Ltd., FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by NEOS Co., Ltd., Polyfox PF-151N manufactured by OMNOVA Co., Ltd., and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred from the viewpoint of excellent print quality, particularly color development, penetration into paper, wettability, and uniform dyeing.

[0138] The content of the surfactant in the ink is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of excellent wettability and ejection stability and improved image quality, it is preferably 0.001% by mass or more and 5% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less.

[0139] <Antifoaming agent> The antifoaming agent is not particularly limited, and examples thereof include silicone-based antifoaming agents, polyether-based antifoaming agents, and fatty acid ester-based antifoaming agents. These may be used alone or in combination of two or more. Among these, silicone-based antifoaming agents are preferred because of their excellent defoaming effect.

[0140] <Preservative and mildew-proof agent> The preservative and mildew-proof agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

[0141] <Rust preventive> The rust preventive is not particularly limited, and examples thereof include acid sulfite and sodium thiosulfate.

[0142] <pH adjuster> The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

[0143] Aspects of the present invention are as follows, for example. <1> An ejection unit that ejects ink, A liquid that exists in the direction in which the ejection unit ejects the ink, and The liquid can hold the ink ejected from the ejection unit in the liquid or on the surface of the liquid, An inkjet printing apparatus characterized by adhering the ink held in the liquid to a printing target. <2> Comprising a support unit on which the printing target can be placed, The support portion is movable up and down in the vertical direction, After the ejection unit ejects the ink, the support unit is moved upward in a state in which the printing object is placed on the support unit, thereby causing the ink held in the liquid to adhere to the printing object. Characterized by <1> The ink ejection device according to claim 1 . <3> The support portion has a liquid permeable material. Characterized by <2> The ink ejection device according to claim 1 . <4> placing the substrate in the liquid; The ejection unit ejects the ink while the printing substrate is immersed in the liquid and the surface of the printing substrate is not exposed above the liquid surface. Characterized by <1> from <3> 2. The ink ejection device according to claim 1 , <5> After the ink is ejected into the liquid, the printing object is placed on the liquid from the surface side of the liquid, and the ink held in the liquid is adhered to the printing object. Characterized by <1> from <3> 2. The ink ejection device according to claim 1 , <6> An ejection unit that ejects ink; a liquid present in a direction in which the ejection section ejects the ink, The ejection unit ejects the ink onto the printing substrate in a state where the printing substrate is immersed in the liquid and a surface of the printing substrate is exposed above the liquid surface. 1. An ink ejection device comprising: <7> A control unit is provided, The control unit is capable of controlling at least one selected from a liquid level of the liquid and a height of the printing substrate in a thickness direction of the printing substrate before the ejection unit ejects the ink. Characterized by <1> from <6> 2. The ink ejection device according to claim 1 , <8> The liquid contains a flocculant. Characterized by <1> from <7> 2. The ink ejection device according to claim 1 , <9> The specific gravity of the liquid is greater than the specific gravity of the ink. Characterized by <1> from <8> 2. The ink ejection device according to claim 1 , <10> a discharge step of discharging ink by a discharge unit that discharges ink toward liquid that is present in a direction in which the ink is discharged; and a deposition step of depositing the ink on a substrate, the liquid is capable of retaining the ink ejected from the ejection portion in the liquid or on a surface of the liquid, The application step applies the ink held in the liquid to a substrate. 13. An ink ejection method comprising: <11> a discharge step of discharging the ink by a discharge unit that discharges the ink toward a liquid that is present in a direction in which the ink is discharged; The ejection step ejects the ink onto the substrate while the substrate is immersed in the liquid and the surface of the substrate is exposed above the liquid surface. 13. An ink ejection method comprising: [Explanation of symbols]

[0144] 1. Ink ejection device 10 Carriage 11 Head 12 Guide rod 13. Aquarium 14 liquid 15 Main frame 16 Lifting mechanism 17 Table 18 Ink 20 Recording medium (printed material) 22 Control section [Prior art documents] [Patent documents]

[0145] [Patent Document 1] JP 2015-155147 A

Claims

1. An ejection unit that ejects ink; a liquid present in a direction in which the ejection section ejects the ink, the liquid is capable of retaining the ink ejected from the ejection portion in the liquid or on a surface of the liquid, The ink held in the liquid is applied to a substrate.

1. An ink ejection device comprising:

2. A support portion on which the printing substrate can be placed is provided, The support portion is movable up and down in the vertical direction, After the ejection unit ejects the ink, the support unit is moved upward in a state in which the printing object is placed on the support unit, thereby causing the ink held in the liquid to adhere to the printing object.

2. The ink ejection device according to claim 1.

3. The support portion has a liquid permeable material.

3. The ink ejection device according to claim 2.

4. placing the substrate in the liquid; The ejection unit ejects the ink while the printing substrate is immersed in the liquid and the surface of the printing substrate is not exposed above the liquid surface.

2. The ink ejection device according to claim 1.

5. After the ink is ejected into the liquid, the printing object is placed on the liquid from the surface side of the liquid, and the ink held in the liquid is adhered to the printing object.

2. The ink ejection device according to claim 1.

6. An ejection unit that ejects ink; a liquid present in a direction in which the ejection section ejects the ink, The ejection unit ejects the ink onto the printing substrate in a state where the printing substrate is immersed in the liquid and a surface of the printing substrate is exposed above the liquid surface.

1. An ink ejection device comprising:

7. A control unit is provided, The control unit is capable of controlling at least one selected from a liquid level of the liquid and a height of the printing substrate in a thickness direction of the printing substrate before the ejection unit ejects the ink.

7. The ink ejection device according to claim 1, wherein the ink ejection device is a nozzle.

8. The liquid contains a flocculant.

7. The ink ejection device according to claim 1, wherein the ink ejection device is a nozzle.

9. The specific gravity of the liquid is greater than the specific gravity of the ink.

7. The ink ejection device according to claim 1, wherein the ink ejection device is a nozzle.

10. a discharge step of discharging the ink by a discharge unit that discharges the ink toward a liquid that is present in a direction in which the ink is discharged; and a deposition step of depositing the ink on a substrate, the liquid is capable of retaining the ink ejected from the ejection portion in the liquid or on a surface of the liquid, The application step applies the ink held in the liquid to a substrate.

13. An ink ejection method comprising:

11. a discharge step of discharging the ink by a discharge unit that discharges the ink toward a liquid that is present in a direction in which the ink is discharged; The ejection step ejects the ink onto the substrate while the substrate is immersed in the liquid and the surface of the substrate is exposed above the liquid surface.

13. An ink ejection method comprising:

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