JP6917319B2 - Inkjet printer ink and inkjet printer - Google Patents

Description

The present invention relates to ink for an inkjet printer and an inkjet printer.

Charge control type inkjet printers are used in a wide range of fields such as foods and electronic parts for printing expiration dates, expiration dates, serial numbers, and the like. The ink of the charge control type inkjet printer is required to have a conductivity of about 1 kΩ · cm. The basic composition of ink for a charge-controlled inkjet printer consists of a resin, a colorant, a conductive agent, and a solvent. Additives such as a leveling agent for controlling the shape of the printed dots are added to this.

The colorant is added to develop the color of the print. The conductive agent is added so that the ink droplets get a proper charge. Specifically, the conductive agent has a function of improving the conductivity of the ink and reducing the resistance. As the conductive agent, for example, as described in Patent Document 1, an organic substance having a salt structure is generally used. Further, the resin is added to hold the colorant or the like on the printed portion. As the leveling agent, a silicone-based compound is generally used. Conventionally, a solvent such as 2-butanone (commonly known as methyl ethyl ketone (MEK)) has been widely used as the solvent. In addition to being able to easily dissolve many resins, MEK has the characteristics that it dries quickly after printing because it has a large vapor pressure, and that printing is not easily faded even if another material is layered immediately after printing. Therefore, it is suitable for printing on many products in a short time such as food. In recent years, with respect to a solvent, a technique using a pyrrolidinium cation has been proposed (for example, Patent Document 2).

International Publication No. 2014/156308 Japanese Unexamined Patent Publication No. 2016-117845

The size of the printed dots is approximately 300 to 400 μm, and is as small as about 300 to 350 μm because the resin surface of polypropylene (PP), polyethylene (PE) cups, bottle caps, and the like is highly hydrophobic. Compared to these, the surface of aluminum cans and glass bottles, which are highly hydrophilic, is about 350 to 400 μm.

Since the resin is mainly responsible for the abrasion resistance and adhesion of printing, the resin can be added to an acceptable viscosity at the time of printing. On the other hand, if the proportion of the colorant or the conductive agent added to the solvent is increased, the abrasion resistance and the adhesiveness tend to decrease. Colorants need to be added to ensure visibility and are difficult to reduce. Therefore, it is desired to reduce the amount of the conductive agent added to the solvent as much as possible.

As described above, an organic substance having a salt structure is generally used as the conductive agent, but a long hydrocarbon chain or a plurality of aromatic substances are used to improve the solubility in the solvent described in MEK and the like and Patent Document 2. It has a ring and the like. Therefore, the molecular weight of the salt added to the solvent in order to obtain the desired conductivity is increased, and as a result, the addition rate of the conductive agent is increased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink for an inkjet printer having a low addition rate of a conductive agent and an inkjet printer using the ink.

As a result of diligent research to solve the above problems, the present inventors have found that when a salt having an anion having a disianamide structure is used as the conductive agent, the resistance is significantly reduced in spite of the low addition rate. We have found that the conductivity can be improved, and have completed the present invention.

The ink jet printer ink according to the present invention that solves the above problems is a charge control type inkjet printer ink containing at least a resin, a colorant, a conductive agent, and a non-aqueous solvent, and the conductive agent is the non-aqueous solvent. It is a salt structure that produces anions and cations in it, and the anions have a disianamide structure and the cations have a nitrogen-containing unsaturated heteromonocyclic structure.

The inkjet printer according to the present invention contains at least a resin, a colorant, a conductive agent, and a non-aqueous solvent, and the conductive agent has a salt structure in which anions and cations are generated in the non-aqueous solvent. Uses an ink for an inkjet printer, which has a disianamide structure and the cation has a nitrogen-containing unsaturated heteromonocyclic structure.

According to the present invention, it is possible to provide an ink for an inkjet printer having a low addition rate of a conductive agent and an inkjet printer using the ink.

It is a schematic diagram explaining the structure of the inkjet printer using the ink for an inkjet printer which concerns on this embodiment. 6 is a graph showing the relationship between the addition rate of the conductive agent and the resistance in the ink for an inkjet printer manufactured in Example 1. In the figure, the horizontal axis is the addition rate (mass%), and the vertical axis is the resistance (Ω · cm). It is a graph which shows the relationship between the addition rate and resistance of the conductive agent in the ink for an inkjet printer manufactured in Example 2. FIG. In the figure, the horizontal axis is the addition rate (mass%), and the vertical axis is the resistance (Ω · cm).

Hereinafter, an embodiment of an ink jet printer ink and an inkjet printer according to the present invention will be described in detail with reference to the drawings as appropriate.

1. 1. Ink Constituent Materials The ink for inkjet printers according to this embodiment (hereinafter, may be simply referred to as "ink") is used for charge control type inkjet printers, and is mainly used as a resin, a colorant, a conductive agent, and non-water. It is composed of a solvent or the like. The ink is produced by stirring these with a stirrer chip, an overhead stirrer, or the like to make them compatible with each other.

(1) Resin Examples of the resin that can be used in the present embodiment include acrylic resin, styrene acrylic resin, polyvinyl butyral resin, polyester resin, and chlorine-containing vinyl acetate. As the resin, any one selected from these can be used alone, or two or more thereof can be used in combination. Further, as the resin, a resin obtained by mixing at least one resin selected from these resins with any other resin can be used. The weight average molecular weight of each of these resins is about several thousand to 20,000. Select those resins that are soluble in the solvent used.

(2) Colorant Examples of the colorant include dyes and pigments.
(A) Dye The dye is not particularly limited as long as it is a material that dissolves in the solvent used, and an appropriate dye can be used. Specifically, the following dyes can be used.
Examples of black dyes include oil black HBB (CI solvent black 3), varifast black 3804 (CI solvent black 34), spirit black SB (CI solvent black 5), and oleosolfast. Examples thereof include black RL (CI solvent black 27), Eisenzot black 8 (CI solvent black 7), and olazole black CN (CI solvent black 28).
Examples of red dyes include Oil Red 5B (CI Solvent Red 27), Varifast Red 1306 (CI Solvent Red 109), Oleosolfast Red BL (CI Solvent Red 132), and Eisen. Examples thereof include Zott Red 1 (CI Solvent Red 24), Orazole Red 3GL (CI Solvent Red 130), Philamid Red GR (CI Solvent Red 225) and the like.
Examples of yellow dyes include Oil Yellow 129 (CI Solvent Yellow 29), Oleosol Brilliant Yellow 5G (CI Solvent Yellow 150), Eisenzot Yellow 1 (CI Solvent Yellow 56), and Ora. Examples thereof include Zol Yellow 3R (CI Solvent Yellow 25).
Examples of blue dyes include oil blue 2N (CI solvent blue 35), varifast blue 1605 (CI solvent blue 38), oleosolfast blue ELN (CI solvent blue 70), and Eisen. Examples thereof include Zott Blue 1 (CI Solvent Blue 25) and Orazole Blue GN (CI Solvent Blue 67).

(B) Pigment The pigment is not particularly limited as long as it is a material that dissolves in the solvent used, and an appropriate pigment can be used. Specifically, the following pigments can be used.
Examples of the black pigment include carbon black. Examples of the white pigment include titanium dioxide, zinc oxide and the like. Examples of the red pigment include cadmium red, Bengara (ferric trioxide), quinacridone red and the like. Examples of the yellow pigment include chrome yellow, cadmium yellow, nickel titanium yellow and the like. Examples of the blue pigment include Prussian blue and copper phthalocyanine. Examples of the green pigment include phthalocyanine green, a mixture of chrome yellow and Prussian blue, titanium cobalt green and the like.
For pigments other than white pigments, pulverized pigments having an average particle size of 100 to 1000 nanometers are added together with an appropriate dispersant. If the white pigment is too small, the hiding rate will decrease, so an average particle size of 200 nanometers or more should be used together with an appropriate dispersant.

(3) Conductive agent (a) Examination of chemical structure Since the ink according to this embodiment is used in an inkjet printer of a charge control type, conductivity is required. Therefore, a conductive agent is added. The conductive agent has a salt structure that produces anions and cations in a non-aqueous solvent. When a large amount of the conductive agent is added, the physical strength such as scratch resistance and adhesion of the ink is lowered. Therefore, it is preferable to reduce the addition rate as much as possible. Therefore, it is desired that the anions and cations have the smallest possible molecular weight among the salt structures constituting the conductive agent.

Halogen ions such as chlorine and bromine are examples of anionic species having a small molecular weight. However, chlorine and bromine are not preferable because they may corrode metal parts inside the ink-filled inkjet printer.
The present inventors have examined the anionic species in detail, if the molecular weight of the elements were calculated by an integer obtained by rounding off decimals, dicyanamide (N ^- (CN) ₂₎ structure, i.e., the molecular weight of dicyanamide ion at 66 Therefore, the molecular weight is smaller than the molecular weight of methanesulfonic acid ion 95, the molecular weight of benzenesulfonic acid ion 157, the molecular weight of toluenesulfonic acid ion 171 and the like. %) Was found to be low. Further, it was found that the salt having a dicyanamide structure is preferable as a conductive agent because there is no possibility of corroding the metal portion inside the inkjet printer. Furthermore, it was also found that the salt having a disianamide structure tends to be more easily dissolved in a solvent of ink for an inkjet printer such as MEK and acetone than other anionic species.

As for the cation species, those having a small molecular weight are preferable. However, when the anion has a disianamide structure, the tetraalkylamine having a long-chain alkyl chain has low solubility in a non-aqueous solvent such as MEK unless the alkyl chain is long to some extent. Specifically, in the case of the tetraalkylamine, it is desirable that the alkyl chain has 4 or more carbon atoms. However, the tetraalkylamine having 4 carbon atoms in the alkyl chain has a molecular weight of 242, the tetraalkylamine having 6 carbon atoms in the alkyl chain has a molecular weight of 354, and the tetraalkylamine having 8 carbon atoms in the alkyl chain has a molecular weight of 466. It also becomes. Further, for example, in the case of tetraphenylamine in which a phenyl group is bonded instead of an alkyl chain, the molecular weight is 322, and in order to improve the solubility in an organic solvent, one fluoro group is introduced into the phenyl group. In the case of (monofluorophenyl) amine, the molecular weight is as high as 394. Therefore, in these cationic species, the addition rate of the conductive agent becomes high, and there is a possibility that the abrasion resistance and the adhesiveness may decrease.
If the cation species is a polycyclic ring (condensed ring), the molecular weight tends to be high, and thus there is a concern that the abrasion resistance and adhesion may be similarly lowered.
Further, when the cation species is a saturated ring, like tetraalkylamine having a long-chain alkyl chain, the solubility in a non-aqueous solvent such as MEK is low unless the alkyl chain is long to some extent. Specifically, in the case of a saturated ring having an alkyl chain as a substituent, it is difficult to secure stable solubility in MEK unless the total number of carbon atoms of the cation species is 15 or more.

Compared to these cation species, the cations of monocyclic nitrogen-containing unsaturated heterocycles, specifically the cations of nitrogen-containing unsaturated hetero5-membered rings, are imidazo if they do not have an alkyl chain in the molecule. The lithium structure (imidazolium ion) has a small molecular weight of 69, and the pyrrolium structure (pyrrolium ion) has a small molecular weight of 68. Further, the pyridinium structure (pyridinium ion), which is a cation of a monocyclic nitrogen-containing unsaturated complex six-membered ring, also has a small molecular weight of 80 when it does not have an alkyl chain in the molecule. In the case of these nitrogen-containing unsaturated heterocycles, the solubility in a non-aqueous solvent such as an organic solvent is ensured by introducing (bonding) an alkyl chain into the nitrogen in the molecule. However, even in this case, if the alkyl chain is too long, the solubility in a non-aqueous solvent (for example, MEK) is lowered. Therefore, for example, when the solvent is MEK and the anion has a disianamide structure, the number of carbon atoms of the alkyl chain introduced into nitrogen having a nitrogen-containing unsaturated complex monocyclic structure, for example, an imidazolium structure is preferably 1 to 8. For the same reason as described above, the pyrollium structure can be dissolved in a solvent such as MEK by introducing two alkyl chains having 3 to 10 carbon atoms (in nitrogen) at the 1-position. In the case of the pyridinium structure as well, for the same reason as described above, by introducing an alkyl chain having 6 to 18 carbon atoms (in nitrogen) at the 1-position, it becomes possible to dissolve in a solvent such as MEK.
By forming the cation into a nitrogen-containing unsaturated complex monocycle in this way, a conductive agent having a dicyanamide salt structure having a small molecular weight can be obtained.

(B) Suitable chemical structure From the above-mentioned chemical structure study, it was found that the anion has a dicyanamide structure and the cation has a nitrogen-containing unsaturated heteromonocyclic structure. In addition, as a result of studies by the present inventors, it was found that the solubility in a ketone solvent such as MEK is particularly improved by bonding the alkyl chain to the nitrogen atom in the heterocycle. It is presumed that this is because the solubility in the hydrophobic organic solvent was improved by arranging the hydrophobic alkyl chain in the vicinity of the hydrophilic ammonium ion.
Therefore, a compound having the following structure of compound 1 group, compound 2 group or compound 3 group is suitable.
In the compound 1 group, R1 and R2 are straight-chain or branched-chain hydrocarbon chains having 1 to 8 carbon atoms. R3 is hydrogen or a straight or branched hydrocarbon chain having 1 to 8 carbon atoms.
In the compound 2 group, R4 and R5 are straight-chain or branched-chain hydrocarbon chains having 3 to 10 carbon atoms.
In the compound group 3, R6 is a straight or branched hydrocarbon chain having 6 to 18 carbon atoms.

The molecular weights of the compounds of the compound 1 group, the compound 2 group, and the compound 3 group were compared. The total number of carbon atoms of the alkyl chain required to ensure solubility in a non-aqueous solvent is 2 for the compound 1 group (at least 1 for each of R1 and R2), and the molecular weight at that time is 163. In the case of the compound 2 group, the total number of carbon atoms required to ensure the solubility in a non-aqueous solvent is 6, and the molecular weight at that time is 218. In the case of the compound 3 group, the number of carbon atoms required to ensure the solubility in a non-aqueous solvent is 6, and the molecular weight at that time is 230. From the above, the compound having a small molecular weight is the compound group 1, which is considered to be the most suitable. Further, when comparing the minimum molecular weights that ensure solubility in non-aqueous solvents, the molecular weight of the compound 1 group is smaller than the molecular weights of the compound 2 group and the compound 3 group, so that the addition rate to the ink is small. There is a merit that it is done.

(4) Solvent Methyl ethyl ketone (MEK) is the mainstream of the ink solvent for the charge control type inkjet printer, and MEK can also be preferably used for the ink according to the present embodiment. In this embodiment, a solvent other than MEK can also be used. As the solvent other than MEK, for example, a ketone solvent such as acetone or methyl isopropyl ketone, dimethoxyethane, ethanol or the like can be used.

Since the conductive agent contained in the ink having the above-mentioned constitution is colorless to light-colored, the influence on the color tone is slight. Further, as described above, since the conductive agent has high conductivity, sufficient conductivity can be imparted to the ink even if the addition rate is low. Further, since the conductive agent is a liquid, the increase in ink viscosity is slight.

2. Inkjet printer The inkjet printer according to the present embodiment can print using the ink according to the present embodiment described above and give a desired print.
FIG. 1 shows the process of ink ejection and landing of a charge-controlled inkjet printer. FIG. 1 is a schematic diagram illustrating a configuration of an inkjet printer 10 using the ink for an inkjet printer according to the present embodiment.

As shown in FIG. 1, the inkjet printer 10 has a nozzle 1, a charging electrode 3, a deflection electrode 4, a gutter 6, and an ink tank (not shown in FIG. 1).
Then, as shown in FIG. 1, in the inkjet printer 10, the ink droplet 2 ejected from the nozzle 1 is charged by the charging electrode 3, and then the direction is controlled by the deflection electrode 4 and landed on the object to be printed 5. do. The unprinted ink is collected from the gutter 6 and returned to the ink tank.

Examples of the present invention are shown below.

(1) Ink preparation Titanium dioxide powder (100 g) having an average particle diameter of 300 nm, polyvinyl butyral resin (32 g) having a hydroxyl value of 130 and a weight average molecular weight of 15,000, and 2-butanone (308 g) are mixed with a bead mill to obtain titanium dioxide. A dispersion was prepared. To this, 1 g of an acrylic resin (100 g) having an acid value of 72 and a weight average molecular weight of 10000, compound 4 (2 g) which is a polydimethylsiloxane derivative having polyethoxy siloxane chains at both ends, and any of the following compounds 5 to 9 was added. 1.5 g or 2 g was added.

Further, 2-butanone was added at 457 g when the addition amount of the compounds 5-9 was 1 g, 456.5 g when the addition amount was 1.5 g, and 456 g when the addition amount was 2 g. Then, the mixture was stirred until all but titanium dioxide was dissolved. In this way, the ink Nos. shown in Table 1 are shown. 1 to 15 were manufactured.
The cation species of compounds 5 to 9 are all 1-ethyl-3-methylimidazolium ions. As the anion species, compound 5 is disianamide ion, compound 6 is hexafluorophosphate ion, compound 7 is methanesulfonic acid ion, compound 8 is p-toluenesulfonic acid ion, and compound 9 is bromine ion.
When the resistance of each ink was measured, the results shown in FIG. 2 were obtained. Note that FIG. 2 is a graph showing the relationship between the addition rate of the conductive agent and the resistance in the ink for an inkjet printer manufactured in Example 1.

The ink using the compound 5 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 1 having a resistance of 2000 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 2 having a resistance of 1430 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 3 was 1100 Ω · cm. Whether or not these inks can be printed was filled in an inkjet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd., and the printing operation was confirmed. As a result, it was confirmed that all the inks (ink Nos. 1 to 3) were printed normally.

The ink using the compound 6 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 4 having a resistance of 2550 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 5 having a resistance of 1850 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 6 was 1440 Ω · cm. In the same manner as above, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, the ink No. 1 having an addition amount of 1.5 g was obtained. Ink No. 5 and an addition amount of 2 g. No. 6 was printed normally, but the ink No. 6 having an addition amount of 1 g. In No. 4, printing was impossible due to poor charging.

The ink using the compound 7 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 7 having a resistance of 3000 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 8 having a resistance of 2050 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 9 was 1580 Ω · cm. In the same manner as above, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, the ink No. 1 having an addition amount of 1.5 g was obtained. Ink No. 8 and an addition amount of 2 g. No. 9 was printed normally, but the ink No. 9 having an addition amount of 1 g was printed. In No. 7, printing was impossible due to poor charging.

The ink using the compound 8 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 10 having a resistance of 4200 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 11 having a resistance of 2750 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 12 was 2200 Ω · cm. In the same manner as above, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, the ink No. of the addition amount of 2 g was increased. No. 12 was printable, but the ink No. 12 having an addition amount of 1 g. Ink No. 10 and an addition amount of 1.5 g. In No. 11, printing was impossible due to poor charging. In addition, the ink No. In the printing of No. 12, printing disorder presumed to be caused by some ink particles having insufficient charge occurred.

The ink using the compound 9 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 13 having a resistance of 3700 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 14 having a resistance of 2600 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 15 was 2100 Ω · cm. In the same manner as above, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, the ink No. of the addition amount of 2 g was increased. No. 15 was printable, but the ink No. 15 having an addition amount of 1 g. Ink No. 13 and an addition amount of 1.5 g. In No. 14, printing was impossible due to poor charging. In addition, the ink No. In the printing of 15, the printing disorder presumed to be due to the ink particles having insufficient charge occurred.

It was found that the cause of the inability to print was that the resistance of the ink was too high. Printing was possible when the ink resistance was approximately 2200 Ω · cm or less, and printing was not possible when the ink resistance was higher than that. Further, it was possible to print without causing print disturbance when the resistance of the ink was about 2050 Ω · cm or less.

From the above results, when comparing the inks to which the compounds 5 to 9 were added, even if the cation species were the same, the compound 5 in which the anionic species was disyanamide ion lowered the resistance of the ink most, and the amount added was small ( It was shown that printing can be performed with the addition rate).

(1) Ink Preparation Similar to Example 1, a bead mill is made of titanium dioxide powder (100 g) having an average particle diameter of 300 nm, polyvinyl butyral resin (32 g) having a hydroxyl value of 130 and a weight average molecular weight of 15,000, and 2-butanone (308 g). To prepare a dispersion of titanium dioxide. To this was added an acrylic resin (100 g) having an acid value of 72 and a weight average molecular weight of 10000, and compound 4 (2 g), which is a polydimethylsiloxane derivative having a polyethoxy siloxane chain at both ends. However, in this example, 1 g, 1.5 g, or 2 g of any of compounds 10 to 12 was added instead of compounds 5 to 9.

Further, 2-butanone was added at 457 g when the addition amount of the compounds 10 to 12 was 1 g, 456.5 g when the addition amount was 1.5 g, and 456 g when the addition amount was 2 g. Then, the mixture was stirred until all but titanium dioxide was dissolved. In this way, the ink Nos. shown in Table 2 are shown. 16 to 24 were manufactured.
The anion species of the compounds 5 used in Example 1 and the compounds 10 to 12 used in Example 2 are all cyanamide ions. The cation species are 1-ethyl-3-methylimidazolium ion for compound 5, tetrabutylammonium ion for compound 10, 1-hexylpyridinium ion for compound 11, and 1,1-propylpyrrolium ion for compound 12.
When the resistance of each ink was measured, the results shown in FIG. 3 were obtained. Note that FIG. 3 is a graph showing the relationship between the addition rate of the conductive agent and the resistance in the ink for an inkjet printer manufactured in Example 2. The results of Compound 5 are also shown in FIG. 3 for comparison.

The ink using the compound 10 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 16 having a resistance of 4400 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 17 having a resistance of 3400 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 18 was 2200 Ω · cm. As in Example 1, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, the ink No. of the addition amount of 2 g was increased. No. 18 was printable, but the ink No. 18 having an addition amount of 1 g. Ink No. 16 and an addition amount of 1.5 g. In No. 17, printing was impossible due to poor charging. In addition, the ink No. In the printing of No. 18, printing disorder presumed to be caused by ink particles having insufficient charge occurred.

The ink using the compound 11 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 19 having a resistance of 2300 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 20 having a resistance of 1900 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 21 was 1450 Ω · cm. As in Example 1, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, it was possible to print with any ink (ink Nos. 19 to 21). However, the ink No. In the printing of 19, the printing disorder presumed to be due to the ink particles having insufficient charge occurred.

The ink using the compound 12 has an addition amount of 1 g (addition rate: 0.1% by mass), and the ink No. Ink No. 22 having a resistance of 2200 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 23 having a resistance of 1800 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 24 was 1380 Ω · cm. As in Example 1, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, it was possible to print with any ink (ink Nos. 22 to 24). However, the ink No. In the printing of 22, the printing disorder presumed to be due to the presence of ink particles having insufficient charge occurred.

From the above results, when comparing the inks to which Compound 5 and Compounds 10 to 12 are added, Compound 5 in which the anion species are the same and the cation species is an unsaturated five-membered ring imidazolium ion is added to the ink. It was shown that when the addition rate is the same, the resistance of the ink is reduced most and printing is possible with a small addition amount (addition rate).
Comparing the compounds 10 and the compounds 11 and 12, the addition rate of the compounds 11 and 12 having a nitrogen-containing unsaturated heteromonocyclic cation to the ink was higher than that of the compound 10 having an alkylammonium cation species. It has also been shown to reduce the resistance of the ink in the same case.

Instead of an acrylic resin (100 g) having an acid value of 72 and a weight average molecular weight of 10,000, a polyester having a weight average molecular weight of 3000 (dicarboxylic acid unit is isophthalic acid: terephthalic acid = 1: 1 and diol unit is propylene glycol) was used. In the same manner as in Example 1 except that only compound 5 is used among the compounds 5 to 9, the ink numbers shown in Table 3 are shown. 25-27 were manufactured.

Ink No. 1 g (addition rate 0.1% by mass) of compound 5 added. Ink No. 25 having a resistance of 1900 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 26 having a resistance of 1340 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 27 was 980 Ω · cm. As in Example 1, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, printing was possible with any ink (ink Nos. 25 to 27), and printing distortion did not occur.
Therefore, it was shown that the compound 5 exhibits high conductivity even if the type of resin is changed.

Table 4 is the same as in Example 1 except that carbon black powder (50 g) and MEK (50 g) having an average particle diameter of 150 nm are used instead of titanium dioxide powder (100 g) having an average particle diameter of 300 nm, and only compound 5 is used. Ink No. shown in 28-30 were manufactured.

Ink No. 1 g (addition rate 0.1% by mass) of compound 5 added. Ink No. 28 having a resistance of 1900 Ω · cm and an addition amount of 1.5 g (addition rate 0.15% by mass). Ink No. 29 having a resistance of 1340 Ω · cm and an addition amount of 2 g (addition rate 0.2% by mass). The resistance of 30 was 980 Ω · cm. As in Example 1, the ink jet printer UX type manufactured by Hitachi Industrial Equipment Systems Co., Ltd. was filled with these inks to confirm the printing operation. As a result, printing was possible with any ink (ink Nos. 28 to 30), and printing distortion did not occur.
Therefore, it was shown that the compound 5 exhibits high conductivity even if the type of pigment is changed.

The ink jet printer ink and the inkjet printer according to the present invention have been described in detail with reference to the embodiments and examples, but the gist of the present invention is not limited to this, and various modifications are included. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 Nozzle 2 Ink droplets 3 Charged electrode 4 Deflection electrode 5 Printed matter 6 Gutter 10 Inkjet printer

Claims (7)

An ink for an inkjet printer with a charge control method that contains at least a resin, a colorant, a conductive agent, and a non-aqueous solvent.
The conductive agent has a salt structure that produces anions and cations in the non-aqueous solvent.
The anion has a disianamide structure and
An ink for an inkjet printer, wherein the cation has a nitrogen-containing unsaturated complex monocyclic structure. In claim 1,
An ink for an inkjet printer, wherein the nitrogen-containing unsaturated complex monocyclic structure is a nitrogen-containing unsaturated complex five-membered ring structure. In claim 2,
An ink for an inkjet printer, wherein the nitrogen-containing unsaturated complex five-membered ring structure has an imidazolium structure. In claim 3,
An ink for an inkjet printer, characterized in that a linear or branched hydrocarbon chain having 1 to 8 carbon atoms is bonded to the 1st and 3rd positions of the imidazolium structure. In claim 2,
The nitrogen-containing unsaturated complex five-membered ring structure is a pyrollium structure, and is characterized in that two straight-chain or branched hydrocarbon chains having 3 to 10 carbon atoms are bonded to the nitrogen atom of the pyrollium structure. Ink for inkjet printers. In claim 1,
The nitrogen-containing unsaturated complex monocyclic structure is a pyridinium structure, and an inkjet printer is characterized in that a straight-chain or branched hydrocarbon chain having 6 to 18 carbon atoms is bonded to a nitrogen atom of the pyridinium structure. Ink for. It contains at least a resin, a colorant, a conductive agent, and a non-aqueous solvent, and the conductive agent has a salt structure that produces anions and cations in the non-aqueous solvent, and the anions have a disianamide structure. An inkjet printer characterized in that cations use ink for an inkjet printer having a nitrogen-containing unsaturated heteromonocyclic structure.

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