阅读说明：本技术 液体排出装置 (Liquid discharge device ) 是由 关口圣之 小桥纪之 畠山拓 渡边敬词 于 2019-08-29 设计创作，主要内容包括：提供一种液体排出装置,其包括：包含预处理液的第一头(11),配置为将预处理液排出到记录介质；第二头(12),在所述记录介质的输送方向,设置在所述第一头(11)的下游,配置为排出墨水；排气单元(14),在所述输送方向,设置在所述第一头(11)的上游,配置为从所述输送方向的下游侧向上游侧排出存在于所述第一头(11)和所述记录介质之间的气体；以及壳体(30),在内部包含所述第一头(11)和所述第二头(12),在内部或外部包含所述排气单元(14),并在所述输送方向,所述排气单元(14)的下游,具有开口(32)。(Provided is a liquid discharge apparatus including: a first head (11) containing a pretreatment liquid configured to discharge the pretreatment liquid to a recording medium; a second head (12) disposed downstream of the first head (11) in a conveyance direction of the recording medium, and configured to discharge ink; an exhaust unit (14) disposed upstream of the first head (11) in the conveyance direction and configured to discharge gas existing between the first head (11) and the recording medium from a downstream side to an upstream side in the conveyance direction; and a housing (30) that contains the first head (11) and the second head (12) inside, contains the exhaust unit (14) inside or outside, and has an opening (32) downstream of the exhaust unit (14) in the conveyance direction.)

1. A liquid discharge apparatus comprising:

a first head containing a pretreatment liquid configured to discharge the pretreatment liquid to a recording medium;

a second head disposed downstream of the first head in a conveyance direction of the recording medium, and configured to discharge ink;

an exhaust unit disposed upstream of the first head in the conveyance direction and configured to discharge gas existing between the first head and the recording medium from a downstream side to an upstream side in the conveyance direction; and

a housing that contains the first head and the second head inside, contains the exhaust unit inside or outside, and has an opening downstream of the exhaust unit in the conveyance direction.

2. The liquid discharge apparatus according to claim 1, wherein the air discharge unit includes a plurality of air discharge units, each air discharge unit being disposed upstream of the first head in the transport direction.

3. The liquid discharge apparatus according to claim 1,

wherein the housing further contains a carriage inside, the carriage being configured to move in a direction perpendicular to the conveying direction,

wherein the first head and the second head are arranged side by side along the conveying direction,

wherein the exhaust unit is disposed upstream of the first head in the conveyance direction and adjacent to the first head in the conveyance direction.

4. The liquid discharge apparatus according to claim 1,

wherein the exhaust unit comprises a plurality of exhaust units,

wherein a total exhaust force of the exhaust units arranged upstream of the first head in the conveying direction is greater than a total exhaust force of the exhaust units arranged downstream of the first head in the conveying direction.

5. The liquid discharge apparatus according to any one of claims 1 to 4, further comprising:

a holder configured to hold the recording medium and to move in the conveying direction, the holder being movable to a position protruding from the opening through the opening.

6. A liquid discharge apparatus as claimed in any of claims 1 to 5, wherein the exhaust unit comprises a fan.

7. The liquid discharge apparatus according to any one of claims 1 to 6, further comprising a shielding member disposed between the first head and the second head in the conveying direction.

8. The liquid discharge apparatus according to claim 7, wherein the shielding member protrudes from a discharge surface of the first head toward the recording medium side.

9. The liquid discharge apparatus according to any one of claims 1 to 8, wherein the pretreatment liquid contains polyvalent metal ions.

Technical Field

The present invention relates to a liquid discharge apparatus.

Background

In recent years, the market in the so-called dtg (direct to goal) field of direct printing of garments, which is a technology of direct printing on clothes such as T-shirts, is expanding year by year. With the rapidly growing demand for sportswear, there is a demand for applying DTG printing technology to polyester media in addition to conventional cotton or cotton-polyester blend media. This trend is recognized not only in the DTG printing field, but also throughout the textile printing field. Even in an ink jet printer equipped with an unwinding and winding mechanism, there is an increasing demand for an ink jet recording system capable of forming images having excellent color developability and various fastness properties on fabrics of various materials including cotton and polyester.

Patent document 1 proposes an ink set for producing a printed matter having high color developability and little bleeding. The ink includes a pretreatment liquid containing polyvalent metal ions and first polymer particles, and second polymer particles. The first polymer particles and the second polymer particles are both crosslinked polyurethane and/or crosslinked polyurethane-polyurea.

In order to reduce the adhesion of liquid mist to a belt cleaner provided between recording heads, patent document 2 proposes providing a partition member that partitions between the recording heads and the belt cleaner.

CITATION LIST

Patent document

[ patent document 1] Japanese unexamined patent application publication No.2012-7418

[ patent document 2] Japanese patent No.4222606

Disclosure of Invention

Technical problem

However, even if the ink set of patent document 1 improves color developability, since mist generated from the pretreatment liquid discharge head adheres to the nozzle formation surface of the inkjet head, ink aggregation is caused, and thus, discharge reliability is poor.

On the other hand, in the image forming apparatus of patent document 2, the partition member provided between the heads has an effect of preventing the mist from contacting the nozzle forming surface of the ink head. However, the effect is insufficient when the pretreatment liquid is discharged from the head. More specifically, in the case of providing a head for discharging the pretreatment liquid, even when the amount thereof is much smaller than that in the conventional case of contact between the inks, clogging of the nozzles or deposition on the nozzle face is caused upon contact with the pretreatment liquid, thereby causing a failure such as bent ejection or the like. Therefore, the effect of mist contact suppression provided by the partition member is insufficient.

In view of the above circumstances, an object of the present invention is to provide a liquid discharge apparatus which is good in discharge reliability even for various recording media such as coated paper, plastic film, fabric, and the like, and can provide an image excellent in color developability.

Means for solving the problems

In order to solve the above problem, an embodiment of the present invention provides a liquid discharge apparatus including: a first head containing a pretreatment liquid configured to discharge the pretreatment liquid to a recording medium; a second head disposed downstream of the first head in a conveyance direction of the recording medium, and configured to discharge ink; an exhaust unit disposed upstream of the first head in the conveyance direction and configured to discharge gas existing between the first head and the recording medium from a downstream side to an upstream side in the conveyance direction; and a housing that includes the first head and the second head inside, includes the exhaust unit inside or outside, and has an opening downstream of the exhaust unit in the conveyance direction.

Effects of the invention

According to an embodiment of the present invention, there is provided a liquid discharge apparatus which is good in discharge reliability even for various recording media such as coated paper, plastic film, fabric, and the like, and can provide an image excellent in color developability.

Drawings

The drawings are intended to depict example embodiments of the invention, and should not be construed as limiting the scope thereof. The drawings are not to be considered as drawn to scale unless explicitly indicated. Also, like or similar reference characters designate like or similar components throughout the several views.

Fig. 1 is a schematic sectional view of a liquid discharge apparatus according to a first embodiment in a direction perpendicular to a conveying direction.

Fig. 2 is a schematic plan view of a liquid discharge apparatus according to a first embodiment.

Fig. 3 is another schematic plan view of the liquid discharge apparatus according to the first embodiment.

Fig. 4 is a schematic side view of the liquid discharge apparatus according to the first embodiment.

Fig. 5 is another schematic side view of the liquid discharge apparatus according to the first embodiment.

Fig. 6 is another schematic plan view of the liquid discharge apparatus according to the first embodiment.

Fig. 7 is a schematic side view of a liquid discharge apparatus according to a second embodiment.

Fig. 8 is a schematic plan view of a liquid discharge apparatus according to a second embodiment.

Fig. 9 is a schematic side view of a liquid discharge apparatus according to a third embodiment.

Fig. 10 is a schematic side view of a liquid discharge apparatus according to a fourth embodiment.

Fig. 11 is a schematic side view of a liquid discharge apparatus according to a fifth embodiment.

Fig. 12 is a schematic side view of a liquid discharge apparatus according to a sixth embodiment.

Fig. 13 is a schematic side view of a comparative example.

Fig. 14 is another schematic side view of the comparative example. .

Detailed Description

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In describing the embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of the present specification is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that perform similar functions, operate in a similar manner, and achieve similar results.

Hereinafter, a liquid discharge apparatus according to some embodiments of the present invention is described with reference to the accompanying drawings. Incidentally, it should be noted that the following embodiments do not limit the present invention, and any deletion, addition, modification, change, and the like, including other embodiments, can be made within a range that can be thought of by those skilled in the art. So long as the effects and features of the present invention can be demonstrated, they are included in the scope of the present invention.

First embodiment

A liquid discharge apparatus according to an embodiment of the present invention is described below.

The liquid discharge apparatus according to an embodiment of the present invention includes: a first head containing a pretreatment liquid configured to discharge the pretreatment liquid to a recording medium; a second head disposed downstream of the first head in a conveyance direction of the recording medium, and configured to discharge ink; an exhaust unit disposed upstream of the first head in the conveyance direction and configured to discharge gas existing between the first head and the recording medium from a downstream side to an upstream side in the conveyance direction; and a housing that includes the first head and the second head inside, includes the exhaust unit inside or outside, and has an opening downstream of the exhaust unit in the conveyance direction.

A preferred embodiment of the liquid discharge apparatus includes an image forming apparatus.

A liquid discharge apparatus according to the present embodiment is shown in fig. 1. In fig. 1, the recording medium is transported in a direction perpendicular to the paper surface. Fig. 1 is a schematic sectional view of a liquid discharge apparatus in a direction perpendicular to a conveyance direction of a recording medium.

As shown in fig. 1, the liquid discharge apparatus includes a carriage 10, a first head 11, a second head 12, a carriage scanning rail 13, an exhaust unit 14, a platen 15, a support member 16, a platen moving stage 17, a maintenance unit 18, a housing 30, and an opening 32.

The platen 15 is configured to hold a recording medium, and the size and the like thereof can be changed as appropriate.

The recording medium is not particularly limited. Examples thereof include, but are not limited to, coated paper, plastic film, fabric, and in addition, clothing such as T-shirt, and paper can be cited.

The platen 15 is supported by a support member 16.

The platen moving stage 17 is a mechanism for moving the platen 15. The platen moving stage 17 is configured to move the platen 15 in a vertical direction (indicated by an arrow (B) in the figure) and in a recording medium conveying direction.

The maintenance unit 18 is a mechanism for performing maintenance of the head. The maintenance unit 18 includes a cover, a suction pump, and a dummy discharge receiver (dummy discharge receiver).

Hereinafter, in the case where the first head 11 and the second head 12 are described without distinction, they may be simply referred to as heads.

The carriage 10 is a housing including a first head 11 and a second head 12. The carriage 10 is also equipped with an encoder sensor, a moving belt, and a lifting mechanism.

The carriage scanning rail 13 is a rail for moving the carriage 10 in a direction perpendicular to the conveying direction of the recording medium.

A direction perpendicular to the conveying direction of the recording medium may also be referred to as a main scanning direction. The main scanning direction is indicated by an arrow (a) in the figure. The conveying direction of the recording medium may also be referred to as a sub-scanning direction. The main scanning direction and the sub-scanning direction are orthogonal to each other.

The first head 11 is a head for discharging the pretreatment liquid. The second head 12 is a head for discharging ink. Hereinafter, in the case where the first head 11 and the second head 12 are described without distinction, they may be simply referred to as heads.

The exhaust unit 14 is a mechanism for exhausting gas present in the apparatus main body 22 to the outside of the apparatus main body 22. The exhaust unit 14 may have a fan. The fan may be connected to the motor.

The casing 30 internally contains the first head 11 and the second head 12, internally or externally contains the exhaust unit 14, and has an opening 32 downstream of the exhaust unit 14 in the conveying direction of the recording medium. The opening 32 allows gas to flow from the opening 32 into the housing 30, and the gas is directed to the exhaust unit 14. This configuration makes it possible to generate a gas flow as described later.

The size, material, and shape of the housing 30 are not particularly limited and may be appropriately changed. The openings 32 are shown in phantom in the drawings for purposes of illustration and not limitation. The position and size thereof may be changed as appropriate.

In the present embodiment, the exhaust unit 14 is disposed outside the housing 30 and is in contact with the housing 30, but the configuration is not limited thereto.

Fig. 2 is a schematic plan view of the liquid discharge apparatus according to the present embodiment in a state before the carriage 10 and the platen 15 are moved.

As shown, the carriage 10 is provided with a first head 11 and a second head 12. In fig. 2, the carriage scanning rail 13 is omitted.

The platen 15 moves along the platen moving guide 19.

An opening 32, shown in phantom, is provided on a face of the housing 30 opposite the exhaust unit 14.

Fig. 3 is another schematic plan view of the liquid discharge apparatus according to the present embodiment, showing a state after the carriage 10 and the platen 15 shown in fig. 2 have been moved.

As shown in the figure, the platen 15 moves along the platen moving guide 19 in the direction indicated by the arrow (C) in the figure. Since the recording medium is kept moving on the platen 15, the moving direction of the platen 15 coincides with the conveying direction of the recording medium.

As shown in the drawing, the second head 12 is disposed downstream of the first head 11 in the conveying direction of the recording medium.

When the platen 15 moves in the direction indicated by the arrow (C) in the drawing, approaching the carriage 10, the carriage 10 scans in the main scanning direction (the direction indicated by the arrow (a) in the drawing) while discharging the liquid from the head. At this time, the first head 11 first discharges the pretreatment liquid to the recording medium, and then the second head 12 discharges the ink to the recording medium.

Fig. 4 is a schematic side view of the liquid discharge apparatus according to the present embodiment. Fig. 5 is an enlarged schematic view of a main portion of fig. 4.

In the present embodiment, the air discharge unit 14 is configured such that the gas existing between the first head 11 and the recording medium (or the platen 15) flows upstream in the conveyance direction of the recording medium. Further, as shown by an arrow (D) in fig. 4, the gas inside the apparatus main body 22 is discharged (exhausted) to the outside.

Therefore, as shown in fig. 5, the gas flow direction in the space between the platen 15 and each head becomes a direction from the second head 12 toward the first head 11 (the direction indicated by the arrow (D) in fig. 5). In other words, the gas existing between the first head 11 and the platen 15 flows upstream in the conveying direction of the recording medium.

As a result, the mist of the pretreatment liquid generated near the first heads 11 hardly reaches the second heads 12, thereby preventing the ink from aggregating. Since the ink is prevented from being accumulated, the discharge reliability is improved.

Further, as shown in fig. 5, the gas in the space between the second head 12 and the platen 15 may also flow upstream in the conveying direction of the recording medium.

Fig. 6 is another schematic plan view of the liquid discharge apparatus according to the present embodiment. Fig. 6 is the same as fig. 3 except that an arrow (D) indicating a gas flow direction is shown.

As shown in the drawing, the liquid discharge apparatus according to the present embodiment is provided with a plurality of air discharge units 14. In the present embodiment, all the air discharge units 14 are arranged upstream of the first heads 11 in the conveying direction of the recording medium (indicated by an arrow (C) in the drawing).

With this configuration, when the gas flows into the housing 30 from the opening 32 and is guided to the exhaust unit 14, the exhaust direction of the gas is directed upstream in the conveying direction of the recording medium, and the above-described effect can be exerted.

It may also be configured to fix the position of the recording medium, transporting the carriage upstream and downstream. In this case, the so-called "upstream side and downstream side of the conveyance direction of the recording medium" may be defined by the conveyance direction with respect to the head. Specifically, the upstream side in the recording medium conveyance direction corresponds to the downstream side in the head conveyance direction, and the downstream side in the recording medium conveyance direction corresponds to the upstream side in the head conveyance direction.

Comparative example

Fig. 13 and 14 show comparative examples that are not included in the scope of the present invention. Fig. 13 is a schematic side view of an image forming apparatus according to a comparative example. Fig. 14 is an enlarged schematic view of a main portion of fig. 13.

In this example, the air discharging unit 14 is disposed downstream in the conveying direction of the recording medium of the head. In this case, as shown in fig. 14, the direction of the air flow is a direction from the first head 11 toward the second head 12. As a result, the mist of the pretreatment liquid easily adheres to the second head 12, thereby causing the ink to coagulate.

Therefore, even if the opening 32 is provided on the upstream side or the downstream side in the conveying direction, the effect of the present invention cannot be obtained.

Second embodiment

Next, a liquid discharge apparatus according to another embodiment of the present invention is described.

The description of the same matters as the above embodiment will be omitted.

Fig. 7 is a schematic side view of the liquid discharge apparatus according to the present embodiment. The liquid discharge apparatus according to the present embodiment differs from the liquid discharge apparatus according to the above-described embodiments in the configuration of the air discharge unit 14.

In the present disclosure, the configuration of the exhaust unit 14 is not particularly limited and may be appropriately changed. For example, in the present embodiment, the exhaust unit 14 may be disposed at an end of the moving range of the platen 15.

Fig. 8 is a schematic plan view of the liquid discharge apparatus according to the present embodiment. The direction (D) of the air flow is opposite to the conveyance direction (C) of the recording medium. By changing the configuration of the exhaust unit 14, the direction (D) of the airflow can be appropriately changed. In the present embodiment, the gas existing between the first head and the recording medium can be caused to flow upstream in the conveying direction of the recording medium, thereby preventing the ink from aggregating.

Third embodiment

Next, a liquid discharge apparatus according to another embodiment of the present invention is described.

The description of the same matters as the above embodiment will be omitted.

In the liquid discharge apparatus according to the present embodiment, the casing further internally contains a carriage configured to move in a direction perpendicular to a conveying direction of the recording medium, the first head and the second head being arranged side by side in the conveying direction. The exhaust unit is disposed upstream of the first head in the transport direction and adjacent to the first head in the transport direction.

Fig. 9 is a schematic side view of the liquid discharge apparatus according to the present embodiment.

In the present embodiment, as shown in the drawing, the air discharging unit 14 is disposed adjacent to the first head 11 on the upstream side in the conveying direction of the recording medium. In the present embodiment, the exhaust unit 14 is directly attached to the carriage 10.

As a result, the direction change of the air flow is small due to the position of the carriage 10, and a more stable effect is exhibited. According to the present embodiment, the gas existing between the first head and the recording medium can be made to stably flow upstream in the conveying direction of the recording medium, so that the ink aggregation can be more reliably prevented.

In addition, since the distance between the air discharging unit 14 and the head is short, the air flow can be made to pass with a large force to the space between the head and the recording medium, so that the adhesion of the pretreatment liquid to the second head 12 can be more reliably prevented.

Fourth embodiment

Next, a liquid discharge apparatus according to another embodiment of the present invention is described.

The description of the same matters as the above embodiment will be omitted.

In the liquid discharge apparatus according to the present embodiment, a plurality of air discharge units are provided, and the total air discharge force of the air discharge units arranged upstream of the first head in the conveying direction of the recording medium is larger than the total air discharge force of the air discharge units arranged downstream of the first head in the conveying direction of the recording medium.

Hereinafter, "exhaust force" and "suction force" are described as synonyms.

Fig. 10 is a schematic side view of the liquid discharge apparatus according to the present embodiment.

As in the present embodiment, the air discharging unit 14 may be disposed downstream of the head in the conveying direction of the recording medium. In this case, since the gas existing between the heads and the recording medium can flow from the second head 12 toward the first head 11, for example, the air discharge unit 14a having a large suction force (flow rate) may be disposed upstream of the heads so as to have a larger suction force than the other air discharge units 14b, 14 c. Here, as shown in fig. 10, the suction force (D) of the discharge unit 14a is greater than the total suction force ((E) + (F)) of the other discharge units 14b and 14 c.

With this configuration, the gas existing between the first head and the recording medium can be made to flow upstream toward the conveying direction of the recording medium. Therefore, the mist of the pretreatment liquid hardly reaches the second head 12, thereby preventing the ink from aggregating.

Generally, the liquid discharge device may have various types of fans, such as a heat exhausting fan, a cooling fan, and a drying fan, in addition to the defogging collecting fan. Even in this case, with the configuration according to the present embodiment, the effect of reducing the ink aggregation can be exerted.

The above-described "total exhaust force of the exhaust units disposed on the upstream side" can be applied to a case where the number of the exhaust units disposed on the upstream side is only one. The same applies to the exhaust unit disposed on the downstream side.

Fifth embodiment

Next, a liquid discharge apparatus according to another embodiment of the present invention is described.

The description of the same matters as the above embodiment will be omitted.

Fig. 11 is a schematic side view of the liquid discharge apparatus according to the present embodiment. In fig. 11, the main part is schematically shown.

The liquid discharge apparatus according to the present embodiment is provided with the shielding member 20 arranged between the first head 11 and the second head 12 in the conveying direction of the recording medium. Therefore, the mist of the pretreatment liquid ejected from the first heads 11 can be more reliably prevented from reaching the second heads 12.

Further, the shielding member 20 protrudes from the discharge surface of the first head 11 toward the recording medium side. Since the lower end of the shielding member 20 protrudes downward from the head, the mist of the pretreatment liquid can be more reliably prevented from reaching the second head 12.

Sixth embodiment

Next, a liquid discharge apparatus according to another embodiment of the present invention is described.

The description of the same matters as the above embodiment will be omitted.

The liquid discharge apparatus according to the present embodiment includes a holder configured to hold a recording medium and to move in a conveyance direction of the recording medium. The holder is movable through the opening of the housing to a position protruding from the opening.

Fig. 12 is a schematic side view of the liquid discharge apparatus according to the present embodiment. In fig. 12, the main part is schematically shown. Fig. 12 shows a state in which the platen 15 has been moved to a position protruding from the opening 32.

In the present embodiment, the platen 15 serves as an example of a holder. Alternatively, the platen 15 and the support member 16 may be combined as a holder.

If a part of the head or the case overlaps with the upper portion of the platen, it is difficult to set a recording medium such as a T-shirt on the platen. Therefore, it is desirable that the platen is movable to protrude beyond the outer wall of the apparatus main body (housing) to the user side.

In the present embodiment, the platen 15 can pass through the opening 32, move to a position protruding from the opening 32, so that the recording medium can be held outside the housing by the holder. In addition, there is no need to secure a space for holding the recording medium in the holder in the housing, which makes it easy to design the structure of the apparatus.

In order to pass the platen 15 through the opening 32, it is possible to cite, for example, that the projected area of the opening is made larger than at least the projected area of the platen as viewed in the conveying direction of the recording medium.

Pretreatment liquid

The pretreatment liquid used in the liquid discharge apparatus according to the embodiment of the present invention is not particularly limited, and may be appropriately selected from known liquids as long as it can be discharged from the head. Preferably, the pretreatment solution contains polyvalent metal ions. The pretreatment liquid may further contain other components such as a resin, as necessary.

The polyvalent metal ion may be appropriately selected from known metal ions. Examples include, but are not limited to, calcium ions, magnesium ions, aluminum ions. These may be used alone, or two or more of them may be used in combination.

The polyvalent metal ions may be contained in the pretreatment liquid by dissolving the water-soluble polyvalent metal salt in the pretreatment liquid.

The polyvalent metal salt may be appropriately selected from known substances. Preferred examples thereof include, but are not limited to, carboxylates (e.g., acetates, lactates), sulfates, nitrates, chlorides, and thiocyanates. These polyvalent metal salts may be used singly or in combination of two or more. Among them, from the viewpoint of image quality such as color developability and bleeding resistance and discharge reliability, carboxylates, sulfates, nitrates, and chlorides having good solubility in water or a water-soluble organic solvent are preferable.

The content of the polyvalent metal ion in the pretreatment liquid is preferably 30 to 700mmol/L, more preferably 60 to 500mmol/L, most preferably 100 to 400mmol/L, from the viewpoints of prevention of bleeding and concentration unevenness, and color developability, fastness, and adhesiveness.

Ink for ink jet recording

The constituent materials of the ink, i.e., the organic solvent, water, colorant, resin, and additive, are described in detail below.

Organic solvent

The organic solvent is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols such as ethers of polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers and the like, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds.

Specific examples of the water-soluble organic solvent include, but are not limited to, 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, 1, 2-hexanediol, 1, 6-hexanediol, 1, 3-hexanediol, 2, 5-hexanediol, 1, 5-hexanediol, glycerol, 1,2, 6-hexanetriol, 2-ethyl-1, 3-hexanediol, propylene glycol, propylene, Polyhydric alcohols such as ethyl-1, 2, 4-butanetriol, 1,2, 3-butanetriol, 2, 4-trimethyl-1, 3-pentanediol, and pentanetriol (petriol); 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; 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, epsilon-caprolactam, and gamma-butyrolactone; amides such as formamide, N-methylformamide, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, and 3-butoxy-N, N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine and triethanolamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol; propylene carbonate, ethylene carbonate, and the like.

In particular, organic solvents having a boiling point of 250 ℃ or less are preferred because they not only function as wetting agents but also provide good drying properties.

In addition, polyol compounds and glycol ether compounds having 8 or more carbon atoms are also preferable. Specific examples of the polyol compound having 8 or more carbon atoms include, but are not limited to, 2-ethyl-1, 3-hexanediol and 2,2, 4-trimethyl-1, 3-pentanediol.

Specific examples of the glycol ether compound include, but are not limited to, 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.

The content of the organic solvent in the ink is not particularly limited and may be appropriately selected to suit a particular application, but is preferably 10 to 60% by mass, more preferably 20 to 60% by mass, from the viewpoint of ink drying property and discharge reliability.

Water (W)

The content of water in the ink is not particularly limited and may be appropriately selected to suit a particular application, but is preferably 10 to 90 mass%, more preferably 20 to 60 mass%, from the viewpoint of ink drying property and discharge reliability.

Coloring agent

Examples of colorants include, but are not limited to, pigments and dyes.

Useful pigments include inorganic pigments and organic pigments. These may be used alone, or two or more of them may be used in combination. Mixed crystals may also be used as colorants.

Useful pigments include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, luster pigments (e.g., gold pigments and silver pigments), and metallic pigments.

Specific examples of the inorganic pigment include, but are not limited to, titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black produced by a known method such as a contact method, a furnace method, a thermal method.

Specific examples of the organic pigment include, but are not limited to, azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perynone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments), dye chelates (e.g., chelates of the basic dye type, chelates of the acidic dye type), nitro pigments, nitroso pigments, aniline black. Among the above-listed pigments, those having good affinity with the solvent are preferred. In addition, resin hollow particles and inorganic hollow particles may be used.

Specific examples of the pigment for black-and-white printing include, but are not limited to, carbon blacks (c.i. pigment black 7) such as furnace black, lamp black, acetylene black, channel black and the like; metals such as copper, iron (c.i. pigment black 11), and titanium oxide; and organic pigments such as aniline black (c.i. pigment black 1).

Specific examples of pigments for color printing include, but are not limited to, c.i. 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, c.i. pigment orange 5, 13, 16, 17, 36, 43, 51, c.i. pigment red 1,2,3, 5, 17, 22, 23, 31, 38, 48:2 (persistent red 2B (ca), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (bright carmine 6B), 60:1, 63:2, 64:1, 81, 83, 88, 101 (carmine), 104, 105, 106, 149 (cadmium), 122, 168 (red), 122, 166, 170, 146, 170, 146, and others, 172. 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, c.i. pigment violet 1 (rhodamine lake), 3, 5:1, 16, 19, 23, 38, c.i. pigment blue-1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, c.i. green 1,4, 7, 8, 10, 17, 18, 36.

The dye is not particularly limited, and an acid dye, a direct dye, a reactive dye, a basic dye may be used. These may be used singly or in combination of two or more.

Specific examples of dyes include, but are not limited to, c.i. acid yellow 17, 23, 42, 44, 79, 142; c.i. acid red 52, 80, 82, 249, 254, 289; c.i. acid blue 9, 45, 249; c.i. acid black 1,2, 24, 94; c.i. food black 1, 2; c.i. direct yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173; c.i. direct red 1,4, 9, 80, 81, 225, 227; c.i. direct blue 1,2, 15, 71, 86, 87, 98, 165, 199, 202; c.i. direct black 19, 38, 51, 71, 154, 168, 171, 195; c.i. reactive red 14, 32, 55, 79, 249; c.i. reactive black 3, 4, 35.

The content of the colorant in the ink is preferably 0.1 to 15% by mass, more preferably 1 to 10% by mass, for the purpose of improving image density, fixability, and discharge stability.

Examples of the method of dispersing the pigment in the ink include a method of introducing a hydrophilic functional group into the pigment to form a self-dispersible pigment, a method of coating the surface of the pigment with a resin to disperse the pigment, and a method of dispersing the pigment using a dispersant.

Examples of the self-dispersible pigment having a hydrophilic functional group introduced into the pigment include pigments (e.g., carbon) which are dispersible in water and to which a functional group such as a sulfone group or a carboxyl group is added.

Examples of the pigment having a surface coated with a resin include pigments which are contained in microcapsules and can be dispersed in water. This may also be referred to as resin coated pigment. In this case, the pigment added to the ink does not need to be entirely covered with the resin, and the pigment may be contained in an uncoated state within a range not to impair the effect of the present invention, and the pigment partially covered may be dispersed in the ink.

Examples of the method of dispersing the dispersion with a dispersant include known low-molecular dispersants typified by surfactants and known methods of dispersing high-molecular dispersants.

As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, and the like can be used depending on the pigment.

For example, a nonionic surfactant RT-100 (available from Physalis oleifera) or a sodium naphthalenesulfonate formalin condensate is preferably used. One kind of the dispersant may be used alone, or two or more kinds may be used in combination.

Pigment dispersion

The ink may be obtained by mixing a material such as water or an organic solvent with a pigment, or may be obtained by mixing a pigment with water or a dispersant to obtain a pigment dispersion and mixing a material such as water or an organic solvent with the pigment dispersion.

The pigment dispersion can be obtained by mixing water, a pigment dispersant, and other ingredients as necessary, dispersing the pigment, and adjusting the particle size of the pigment. Preferably, the dispersion is carried out by means of a disperser.

The particle size of the pigment dispersed in the pigment dispersion is not particularly limited, but the maximum frequency in terms of the maximum number is preferably in the range of 20 to 500nm, and more preferably in the range of 20 to 150nm, from the viewpoint of good dispersion stability of the pigment, ejection stability, and high image quality such as image density. The pigment particle diameter can be measured using a particle size analyzer (Nano track Wave-UT151, available from Microtrack BEL).

The content of the pigment in the pigment dispersion is not particularly limited, and may be appropriately selected according to the purpose, and is preferably 0.1 to 50% by mass, more preferably 0.1 to 30% by mass, from the viewpoint of obtaining good discharge stability and improving the image density.

The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator, or the like, if necessary.

Resin composition

The kind of the resin contained in the ink is not particularly limited and may be appropriately selected according to the purpose. Specific examples thereof include, but are not limited to, polyurethane resins, polyester resins, acrylic resins, vinyl acetate resins, styrene resins, butadiene resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, and acrylic silicone resins.

Resin particles formed of these resins may be used. The ink can be obtained by mixing water as a dispersion medium, dispersing resin particles, and materials such as a color material and an organic solvent in a resin emulsion state. As the resin particles, appropriately synthesized resin particles may be used, or commercially available products may be used. These resin particles may be used alone or in combination of plural kinds.

The volume average particle diameter of the resin particles is not particularly limited and may be appropriately selected according to the purpose. The volume average particle diameter is preferably 10 to 1,000nm, more preferably 10 to 200nm, and still more preferably 10 to 100nm, from the viewpoint of obtaining good fixability and high image hardness.

The volume average particle diameter can be measured using, for example, a particle size analyzer (Nano track Wave-UT151, manufactured by Microtrack BEL).

The content of the resin is not particularly limited and may be appropriately selected depending on the purpose. From the viewpoint of ink fixability and storage stability, the amount is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, based on the total amount of the ink.

The particle size of the solid content in the ink is not particularly limited and may be appropriately selected according to the purpose. The maximum frequency of the particle size of the solid portion in the ink is preferably 20 to 1000nm, more preferably 20 to 150nm in terms of the maximum number, from the viewpoint of improving the discharge stability and the image quality such as the image density. The solid content includes resin particles, pigment particles and the like. The particle diameter can be measured using, for example, a particle size analyzer (Nano track Wave-UT151, manufactured by Microtrack BEL Co.).

Additive agent

The ink may further comprise a surfactant, a defoamer, an anti-corrosion and anti-mildew agent, a rust inhibitor, and/or a pH adjuster.

Interfacial activator

As the surfactant, any of a silicon-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.

The silicon-based surfactant is not particularly limited and may be appropriately selected according to the purpose. Among them, a silicon-based surfactant which does not decompose even at a high pH is preferable. Specific examples of the silicon-based surfactant include, but are not limited to, side chain-modified polydimethylsiloxane, both terminal-modified polydimethylsiloxane, single terminal-modified polydimethylsiloxane, and side chain both terminal-modified polydimethylsiloxane. A silicon-based surfactant having a polyoxyethylene group and/or a polyoxyethylene polyoxypropylene group as a modifying group is particularly suitable because it exhibits good properties as an aqueous surfactant. Further, as the silicon-based surfactant, a polyether-modified silicon-based surfactant can be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into a side chain of a Si portion of dimethylsiloxane.

As the fluorine-based surfactant, including, but not limited to, a perfluoroalkylsulfonic acid compound, a perfluoroalkylcarboxylic acid compound, a perfluoroalkylphosphate compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain are particularly suitable because of low foaming property. As the above perfluoroalkyl sulfonic acid compound, but not limited to perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonic acid salt are included. As the above perfluoroalkyl carboxylic acid compounds, there are included, but not limited to, perfluoroalkyl carboxylic acids, perfluoroalkyl carboxylic acid salts. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain as described above includes, but is not limited to, sulfuric acid ester salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group in a side chain, and salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group in a side chain. Examples of the counter ion of the salt in the fluorine-based surfactant include, but are not limited to, Li, Na, K, NH₄、NH₃CH₂CH₂OH、NH₂(CH₂CH₂OH)₂、NH(CH₂CH₂OH)₃。

As the above amphoteric surfactant, there may be mentioned, but not limited to, laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethyl betaine.

As the above nonionic surfactant, there may be mentioned, but not limited to, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, ethylene oxide adducts of acetylene alcohols.

The anionic surfactant includes, but is not limited to, polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, and polyoxyethylene alkyl ether sulfate.

These surfactants may be used alone or in combination.

The silicon-based surfactant is not particularly limited and may be appropriately selected according to the purpose. Including, but not limited to, side chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, single-end-modified polydimethylsiloxane, side chain both-end-modified polydimethylsiloxane, polyether-modified silicon-based surfactant having polyoxyethylene group and/or polyoxyethylene polyoxypropylene group as a modifying group, and showing good properties as an aqueous surfactant, are particularly suitable.

As such a surfactant, those appropriately synthesized or commercially available ones may be used. Commercially available products are available from BYK CHEMIE, shin-Etsu CHEMICAL Co., Ltd., Silicon Dow Corning Toray, Japan latex Co., Ltd., KYOEISHA CHEMICAL Co., Ltd.

The polyether-modified silicon surfactant is not particularly limited, and may be appropriately selected according to the purpose, and includes, but is not limited to, compounds represented by the general formula (S-1) in which a polyalkylene oxide structure is introduced into a side chain of the Si portion of dimethylpolysiloxane.

[ chemical formula 1]

X＝-R(C₂H₄O)_a(C₃H₆O)_b R^*

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

As the polyether-modified Silicon surfactant, commercially available products including, but not limited to, KF-618, KF-642, KF-643 (shin-Etsu chemical Co., Ltd.), EMLEX-SS-5602, SS-1906EX (Japan latex Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2163, FZ-2164(Silicon Dow Corning Toray Co., Ltd.), BYK-33, BYK-387(BYK CHEMIE Co., Ltd.), TSF4440, TSF4452 and TSF4453 (Toshiba Silicon Co., Ltd.) can be used.

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

As the fluorine-based surfactant, there are included, but not limited to, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in a side chain. Among these, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain are preferable because of their low foaming properties, and fluorine-based surfactants represented by the general formulae (F-1) and (F-2) are particularly preferable.

[ chemical formula 2]

CF₃CF₂(CF₂CF₂)_m-CH₂CH₂O(CH₂CH₂O)_nH general formula (F-1)

In the compounds 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, for imparting water solubility.

C_nF_2n+1-CH₂CH(OH)CH₂-O-(CH₂CH₂O)_a-Y formula (F-2)

In the compound represented by the above general formula (F-2), Y is H or C_mF_2m+1(m is an integer of 1 to 6), or CH₂CH(OH)CH₂-C_mF_2m+1(m is an integer of 4 to 6), or CpF_2p+1(p is an integer of 1 to 19); n is an integer of 1-6; a is an integer of 4 to 14.

As the fluorine-based surfactant, commercially available products can be used.

As the commercially available products, there are included, but not limited to, SURLON S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by ASAHI GLASS Co.); FLUORAD FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co.); MEGAFACE F-470, F-1405, F-474 (all manufactured by Dainippon ink chemical industries, Inc.); ZONYL TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, CAPSTONE FS-30, FS31, 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 corporation); POLY FOX PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by OMNOVA Inc.); unidyne DSN-403N (Daikin industries, Inc.). Among them, FS-3100, FS-34, FS-300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW, POLY FOX PF-151N manufactured by OMNOVA, and Unidyne DSN-403N manufactured by Daikin industries, are particularly preferable from the viewpoint of improving good printing quality, particularly remarkably improving color development, permeability to paper, wettability, and leveling property.

The content of the surfactant in the ink is not particularly limited, and may be appropriately selected according to the purpose, and is preferably 0.001 to 5% by mass, more preferably 0.05 to 5% by mass, from the viewpoint of excellent wettability and discharge stability and improvement of image quality.

Defoaming agent

The defoaming agent is not particularly limited, and includes, but is not limited to, a silicon-based defoaming agent, a polyether-based defoaming agent, a fatty acid ester-based defoaming agent, and the like. These may be used alone or in combination of two or more. Among them, a silicon-based defoaming agent is preferable in terms of excellent defoaming effect.

Antiseptic and mildew-proof agent

As the preservative and mildewcide, there is no particular limitation, and may be appropriately selected depending on the purpose, and specific examples include, but are not limited to, 1, 2-benzothiazepine-3-one and the like.

Rust inhibitor

As the rust inhibitor, there is no particular limitation, and may be appropriately selected depending on the purpose, and specific examples include, but are not limited to, acid sulfite, sodium thiosulfate.

pH regulator

The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or more, and may be appropriately selected according to the purpose, and specific examples include, but are not limited to, amines such as diethanolamine, triethanolamine, and the like.

The physical properties of the ink are not particularly limited and may be appropriately selected according to the purpose, and for example, the viscosity, surface tension, and pH are preferably in the following ranges.

The viscosity of the ink at 25 ℃ is preferably 5 to 30 mPas, more preferably 5 to 25 mPas, from the viewpoint of improving print density and character quality and obtaining good discharge property. Here, the viscosity can be measured by, for example, a rotational viscometer (RE-80L, manufactured by eastern industries). The measurement conditions were as follows:

standard conical rotor (1 degree 34' XR 24)

Amount of sample liquid: 1.2mL

Revolution number: 50rpm

Measuring time of three minutes

The surface tension of the ink is preferably 35mN/m or less, more preferably 32mN/m or less at 25 ℃ from the viewpoint of appropriately leveling the ink on a recording medium and shortening the ink drying time.

The pH of the ink is preferably 7 to 12, more preferably 8 to 11, from the viewpoint of preventing corrosion of metal parts in contact with the liquid.

Post-treatment liquid

The post-treatment liquid is not particularly limited as long as it can form a transparent layer. The post-treatment liquid may be prepared by mixing an organic solvent, water, a resin, an interfacial activator, a defoaming agent, a pH adjuster, an anticorrosive and mildewproof agent, and/or a rust preventive agent. The post-treatment liquid may be applied to the entire area of the recording area formed on the recording medium, or may be applied only to the area where the ink image is formed.

Recording medium

The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, and the like can be used, and a good image can be formed even if an impermeable base material is used.

The term "non-permeable substrate" means a substrate having a surface with low water permeability and absorbency, and includes a material having a plurality of hollow spaces inside but not opening to the outside. More quantitatively, an impermeable substrate means from the start of contact to 30 milliseconds, as measured according to the Bristow method^1/2Has a water absorption of 10mL/m²Or less substrate.

As the above-mentioned impermeable base material, specific preferred examples include, but are not limited to, plastic films such as vinyl chloride resin films, polyethylene terephthalate (PET) films, polypropylene films, polyethylene films, polycarbonate films, and the like.

The recording medium is not limited to an article used as a general recording medium. Examples of articles that can be used as recording media include: building materials such as wallpaper, flooring, tile, and the like; cloth for clothing such as T-shirts; a textile; and leather. Further, by adjusting the arrangement of the transport path of the recording medium, ceramics, glass, metal, or the like can be used as the recording medium.

Examples

A further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting. In the following description, unless otherwise specified, "parts" generally means "parts by mass".

Synthesis of monomer (1)

First, 24.8g (210mmol) of 1, 6-hexanediol (available from Tokyo chemical Co., Ltd.) was dissolved in 280mL of dichloromethane, and 8.3g (105mmol) of pyridine was further added thereto.

After the lapse of 2 hours, a solution prepared by dissolving 20.0g (105mmol) of 2-naphthoyl chloride (manufactured by Tokyo chemical Co., Ltd.) in 40mL of methylene chloride was added dropwise to the above solution while stirring, and then the mixture was stirred at room temperature for 6 hours. After washing the reaction mixture with water, the organic phase was separated, dried over magnesium sulfate and the solvent was evaporated. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride/methanol (volume ratio: 98/2) as an eluent, to obtain 21.0g of reaction intermediate (I-1) represented by the following structural formula (I-1).

[ chemical formula 3]

Next, 16.8g (62mmol) of the reaction intermediate (I-1) was dissolved in 20mL of dried methyl ethyl ketone and heated to 60 ℃. To the above solution was added dropwise a solution of 9.6g (62mmol) of 2-methacryloyloxyethyl isocyanate (KARENZ MOI, available from SHOWA AND ELECTRICAL CO., LTD.) dissolved in 20mL of dried methyl ethyl ketone over 1 hour, followed by stirring and dropwise addition, and then stirring at 70 ℃ for 12 hours. The obtained liquid was cooled to room temperature, and then the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride/methanol (volume ratio: 99/1) as an eluent, to obtain 22.8g of monomer (1) represented by the following structural formula.

[ chemical formula 4]

Synthesis of copolymer 1

First, 1.80g (25.0mmol) of acrylic acid (obtained from Aldrich) and 8.51g (25.0mmol) of monomer (1) were dissolved in 16mL of dried methyl ethyl ketone to prepare a monomer solution. Next, the 10% monomer solution was heated to 75 ℃ under argon flow. To the heated monomer solution, another solution prepared by dissolving 0.410g (2.50mmol) of 2,2' -azobis (butyronitrile) (manufactured by Tokyo chemical Co., Ltd.) in the remaining monomer solution was added dropwise over 1.5 hours, followed by stirring at 75 ℃ for 6 hours. The resulting reaction solution was cooled to room temperature, and added to hexane. The precipitated copolymer was filtered and dried under reduced pressure to obtain 12.2g of copolymer 1 (weight-average molecular weight (Mw) was 9,400).

Preparation of a Black pigment Dispersion

The materials listed below were premixed and subjected to a 7-hour cyclic dispersion treatment using a disk type bead mill (manufactured by Shinmau Enterprises, model KDL, charged with zirconia ball media having a diameter of 0.3 mm). Thus, a black pigment dispersion (pigment concentration of 15 mass%) was prepared.

15 parts of carbon black pigment (NIPEX 90, available from Orion Engineered Carbons Inc.)

-copolymer 1: 2 portions of

Ion-exchanged water: 83 portions of

Preparation of resin particle Dispersion 1

The resin particle dispersion liquid 1 was prepared by the following procedure.

A300 mL flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a condenser was charged with 87.0 parts of ion-exchanged water, heated to 70 ℃ under a nitrogen stream, and held for 2 hours. On the other hand, 30.0 parts of methyl methacrylate, 52.0 parts of 2-ethylhexyl acrylate, 8 parts of PME-1000 (methoxypolyethylene glycol methyl methacrylate, obtained from NOF Co.), 5 parts of vinyltriethoxysilane, 1.5 parts of AKUARON HS-10 (obtained from DKS Co.), and 43 parts of ion-exchanged water were mixed, and an emulsion was prepared using a homogenizing mixer.

Subsequently, 3.0 parts of a 10% AKUARON HS-10 aqueous solution and 2.6 parts of a 5% ammonium persulfate aqueous solution were charged into the flask, and then, the above emulsion was continuously dropped thereinto over a period of 2.5 hours. Further, 0.5 part of a 5% aqueous solution of ammonium persulfate was added dropwise thereto every 1 hour until 3 hours passed from the start of the dropwise addition. After completion of the dropwise addition, the flask contents were aged at 70 ℃ for 2 hours, then cooled to room temperature, adjusted to pH 7-8 with 28% ammonia water, and made to 30% solid with ion-exchanged water. Thus, a resin particle dispersion liquid 1 was prepared.

Preparation of resin particle Dispersion 2

The resin particle dispersion liquid 2 was prepared by the following procedure.

First, a 500mL separable flask equipped with a stirrer, a thermometer, and a condenser was charged with 74 parts of T5651 (polycarbonate diol, manufactured by asahi chemical company), 10 parts of dimethylolpropionic acid, 50 parts of hydrogenated MDI (methylene diphenyl diisocyanate), and 90 parts of acetone dehydrated with a molecular sieve, and heated to 70 ℃ under a nitrogen stream. Then, 200ppm of tin 2-ethylhexanoate was added thereto, and the reaction was carried out at 70 ℃ for 3 to 10 hours while measuring the isocyanate concentration in the system. Next, the temperature in the system was lowered to 40 ℃, 8 parts of triethylamine was added, and then 270 parts of ion-exchanged water was added while stirring at 300rpm, and the mixture was stirred for 1 hour. Then, 3 parts of diethylenetriamine was added thereto and stirred for 3 to 6 hours. Then, the flask contents were cooled to room temperature, the solvent was distilled off by an evaporator, and the solid concentration was adjusted to 30% with ion-exchanged water. Thus, a resin particle dispersion liquid 2 was prepared.

Preparation of pretreatment solution

The following materials were mixed, stirred for one hour, and then pressure-filtered with a 1.2 μm cellulose acetate membrane filter to prepare a pretreatment liquid. An amount of ion-exchanged water was added so that the total amount became 100 parts.

-propylene glycol: 20 portions of

-3-methoxy-3-methyl-1-butanol: 10 portions of

WET 270 (available from Evonik Industries AG): 0.5 portion

BYK 348 (available from BYK Japan): 0.5 portion

EnviroGem (registered trademark) AD01 (available from Air Products and Chemicals): 0.5 portion

-PROXEL LV: 0.3 part

-magnesium chloride hexahydrate: 5 portions of

Resin particle dispersion 1: 25 portions of

Preparation of Black ink

The following materials were mixed, stirred for 1 hour, and then pressure-filtered with a 1.2 μm cellulose acetate membrane filter to prepare a black ink. An amount of ion-exchanged water was added so that the total amount became 100 parts.

-propylene glycol: 20 portions of

-triethylene glycol: 5 portions of

WET 270 (available from Evonik Industries AG): 0.5 portion

BYK 348 (available from BYK Japan): 0.5 portion

EnviroGem (registered trademark) AD01 (available from Air Products and Chemicals): 0.5 portion

-PROXEL LV: 0.3 part

-black pigment dispersion: 33 portions of

Resin particle dispersion 2: 30 portions of

Examples 1 to 5 and comparative example 1

In embodiments 1 to 5, each of the liquid discharge apparatuses according to the above-described first to fifth embodiments is filled with the pretreatment liquid and the black ink. As comparative example 1, the liquid discharge apparatus of fig. 13 and 14 was filled with the pretreatment liquid and the black ink.

In each example or comparative example, the following evaluations were performed.

Reliability of continuous discharge

In each example or comparative example, the pretreatment liquid and the black ink were continuously discharged for up to 8 hours under an environment of a temperature of 40 ℃ and a relative humidity of 20%, and the time until the black ink droplets could not be stably discharged from the nozzles was measured. Based on the obtained time, the continuous discharge reliability was evaluated based on the following evaluation criteria.

Evaluation criteria

A +: even if 3 hours have elapsed from the start of discharge, no deactivation or discharge failure was observed once.

A: even if 1 hour passed from the start of discharge, no deactivation or discharge failure was observed once.

B: after 30 minutes and less than 1 hour from the start of discharge, no start-up or discharge failure was observed.

C: no priming or discharge failure was observed in less than 30 minutes from the start of discharge.

Evaluation of image Density of Plastic film

In each of examples and comparative examples, the pretreatment liquid was added at 0.5mg/cm²Was uniformly applied to a corona-treated surface of a PYLEN (registered trademark) film P2111 (obtained from TOYOBO corporation) having a thickness of 20 μm. Then, in an undried state, at a rate of 1.0mg/cm²The amount of adhesion of (2) was coated with black ink to form a solid image. The solid images were dried for 1 minute in a hot air circulation oven set at 100 ℃ to obtain images for evaluation of each example or comparative example. The image was evaluated for Optical Density (OD) by measuring the evaluation image with X-rite exact.

Evaluation criteria

A: OD of 2.4 or more

B: OD of 2.0 or more and less than 2.4

C: OD less than 2.0

Color rendering of fabrics

In each of examples and comparative examples, the pretreatment liquid was added at 0.5mg/cm²The amount of the coating was uniformly applied to a polyester T-shirt (glimmer 00300-ACT, white) available from TOMS. Then, in an undried state, at a rate of 1.5mg/cm²The amount of adhesion of (2) was coated with black ink to form a solid image. The solid image was dried for 1 minute by hot pressing set to 160 ℃, and an image for evaluation of each example or comparative example was obtained. The evaluation image was measured by X-rite exact to evaluate the Optical Density (OD) of the image.

Evaluation criteria

A: OD of 1.3 or more

B: OD is 1.2 or more and less than 1.3

C: OD less than 1.2

The evaluation results are shown in Table 1.

TABLE 1

		Reliability of continuous discharge	Plastic film image density	Color rendering of fabrics
					Example 1	First embodiment	A	A	A
Example 2	Second embodiment	A	A	A
					Example 3	Third embodiment	A+	A	A
Example 4	Fourth embodiment	A	B	A
					Example 5	Fifth embodiment	A+	A	A
Comparative example 1	FIGS. 13 and 14	C	C	C

In embodiment 3, since the air discharging unit was provided in the carriage and the distance between the air discharging unit and the head became shorter, the adhesion of the pretreatment liquid to the second head was more prevented, and thereby the continuous discharge reliability was evaluated as "a +".

In example 5, since the shielding member was provided, the adhesion of the pretreatment liquid to the second head was more prevented, and thereby the continuous discharge reliability was evaluated as "a +".

In comparative example 1, the mist of the pretreatment liquid adhered to the second head, causing ink aggregation, and the discharge reliability, the image density, and the color developability were inferior.

The above examples are illustrative and not limiting of the invention. Accordingly, many additional modifications and variations are possible in light of the above teaching. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the invention.

The present patent application is based on and claims priority from japanese patent application nos. 2018-164323 and 2019-107142 filed in the japanese patent office at 2018, 3.9 and 2019, 7.6.7, the entire disclosures of each of which are incorporated by reference.

List of reference numerals

10 carriage

11 first head

12 second head

13 carriage scanning guide

14 exhaust unit

15 pressing plate

16 support member

17 platen moving table

18 maintenance unit

19 pressing plate moving guide rail

20 Shielding component

22 device body

30 casing

32 opening

The claims (modification according to treaty clause 19)

1. A liquid discharge apparatus comprising:

a first head containing a pretreatment liquid configured to discharge the pretreatment liquid to a recording medium;

a second head disposed downstream of the first head in a conveyance direction of the recording medium, and configured to discharge ink;

an exhaust unit disposed upstream of the first head in the conveyance direction and configured to discharge gas existing between the first head and the recording medium from a downstream side to an upstream side in the conveyance direction; and

a housing that contains the first head and the second head inside, contains the exhaust unit inside or outside, and has an opening downstream of the exhaust unit in the conveyance direction.

2. The liquid discharge apparatus according to claim 1, wherein the air discharge unit includes a plurality of air discharge units, each air discharge unit being disposed upstream of the first head in the transport direction.

3. The liquid discharge apparatus according to claim 1,

wherein the housing further contains a carriage inside, the carriage being configured to move in a direction perpendicular to the conveying direction,

wherein the first head and the second head are arranged side by side along the conveying direction,

wherein the exhaust unit is disposed upstream of the first head in the conveyance direction and adjacent to the first head in the conveyance direction.

4. The liquid discharge apparatus according to claim 1,

wherein the exhaust unit comprises a plurality of exhaust units,

wherein a total exhaust force of the exhaust units arranged upstream of the first head in the conveying direction is greater than a total exhaust force of the exhaust units arranged downstream of the first head in the conveying direction.

5. The liquid discharge apparatus according to any one of claims 1 to 4, further comprising:

a holder configured to hold the recording medium and to move in the conveying direction, the holder being movable to a position protruding from the opening through the opening.

6. A liquid discharge apparatus as claimed in any of claims 1 to 5, wherein the exhaust unit comprises a fan.

7. The liquid discharge apparatus according to any one of claims 1 to 6, further comprising a shielding member disposed between the first head and the second head in the conveying direction.

8. The liquid discharge apparatus according to claim 7, wherein the shielding member protrudes from a discharge surface of the first head toward the recording medium side.

9. The liquid discharge apparatus according to any one of claims 1 to 8, wherein the pretreatment liquid contains polyvalent metal ions.

10. The liquid discharge apparatus according to claim 1, further comprising:

a carriage on which the first head and the second head are mounted, the carriage being configured to move in a direction perpendicular to the conveying direction; and

a maintenance unit configured to perform maintenance of the first head and the second head,

wherein the second head, the first head, and the exhaust unit are arranged in this order in an overlapping manner from the opening side in the conveying direction when the carriage is positioned above the maintenance unit.