JP2008297526A - Inkjet recording ink and inkjet recording unit using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain inexpensive inkjet recording ink that has excellent weather resistance and can store images for a long period of time and an inkjet recording unit using the same. <P>SOLUTION: The inkjet recording ink comprises at least one kind of dye selected from the group consisting of azo dye, anthraquinone dye, anthrapyridone dye and phthalocyanine dye. The dye contains a group having a flavonoid or its glycoside structure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes an ink jet recording head that includes an ink jet recording head that ejects ink onto a recording medium and performs recording according to print data and image data (hereinafter referred to as recording data), and an ink jet using the same. Regarding the recording unit. More specifically, the present invention relates to an ink for ink jet recording that enables high speed and inexpensive recording and can create a record that can be stored for a long period of time, and an ink jet recording unit using the same.

  An ink jet recording apparatus is a recording apparatus that forms an image by ejecting a single color ink or a plurality of color inks corresponding to color recording onto a recording medium such as paper, cloth, OHP paper, and a printed circuit board. In general, an ink jet recording apparatus includes a carriage on which an ink jet recording unit including an ink tank and an ink jet recording head (referred to as a recording head) is mounted, means for reciprocating the carriage, a transport unit that transports a recording medium, And a control unit for controlling them.

  In such an ink jet recording apparatus, a recording head having an ink discharge port is continuously scanned in a direction intersecting the recording medium conveyance direction (sub-scanning direction), for example, a substantially perpendicular main scanning direction. Ink is discharged while Further, the recording medium is intermittently conveyed by a distance equal to the recording width, thereby performing recording according to the recording data on the recording medium. As described above, since the ink jet recording apparatus performs recording by ejecting ink directly onto a recording medium in accordance with the recording data, it is widely used because it can perform simple and inexpensive recording.

  In addition, the ink jet recording apparatus can easily cope with full color by including a recording head for a plurality of colors of ink. Such a full-color ink jet recording apparatus is usually equipped with a recording head corresponding to four colors of ink including black (B) in the three primary colors of yellow (Y), magenta (M) and cyan (C).

  For yellow and black inks, azo dyes that are easy to synthesize and are rich in color are often used. This azo dye has a matrix structure as shown in Formula (13).

  Magenta inks are often synthesized with anthraquinone dyes, anthrapyridone (also known as ammonkelidone, pyridantron) dyes, and phthalocyanine dyes that are easy to synthesize and are rich in color. Anthraquinone dyes have a matrix structure as shown in formula (14).

  Anthrapyridone has a matrix structure as shown in Formula (15).

  Phthalocyanine has a matrix structure as shown in Formula (16).

  In recent years, with the widespread use of inkjet recording apparatuses that are sharp and excellent in color, and that are simple and inexpensive, recording characteristics equivalent to silver halide photography and long-term storage are required for images from inkjet recording apparatuses. Therefore, there is a need for an ink having further excellent weather resistance. In conventional ink jet recording inks, dye molecules may be oxidized and discolored or discolored by active oxygen or ozone generated by sunlight or room light. There is a technique using an antioxidant against such deterioration of the dye molecules. This technique includes a method of containing an antioxidant in a recording medium (Patent Documents 1 to 4 and the like) and a method of adding an antioxidant to an ink (Patent Documents 5 to 7 and the like).

However, in the method of adding an antioxidant to the recording medium, the whiteness of the recording medium where the ink is not fixed decreases due to the color of the antioxidant itself or a product generated by oxidation of the antioxidant. There is a problem. In the method of adding an antioxidant to the ink, the coloring material and the antioxidant contained in the ink are fixed separately on the recording medium, and the antioxidant for the coloring material is different due to the difference in solubility. Depending on the properties of the recording medium, it may not be able to exhibit sufficient weather resistance.
Japanese Patent Laid-Open No. 1-115677 JP 2001-270219 A JP 2001-301315 A JP 2001-71627 A JP-A 62-19068 JP 10-324071 A JP 2001-81389 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet recording ink that is excellent in weather resistance, can store images for a long period of time, and is inexpensive, and an ink jet recording unit using the ink. There is to do.

  As a result of intensive studies, the present inventors have found that dyes combined with flavonoids and their glycosides that are extremely susceptible to oxidation are less susceptible to changes in color tone, and the weather resistance is dramatically improved. The knowledge that the whiteness of a part is not reduced was obtained.

  That is, the present invention is an ink jet recording ink containing at least one dye selected from the group consisting of azo dyes, anthraquinone dyes, anthrapyridone dyes and phthalocyanine dyes, wherein the dye is a flavonoid or a saccharide structure thereof An ink for ink-jet recording comprising a group having

  According to another aspect of the present invention, there is provided an ink jet recording unit comprising an ink tank for storing the ink for ink jet recording and an ink jet recording head.

  The present inventors presume the mechanism for improving the weather resistance of the dye as follows. The colored portion in the dye is susceptible to oxidation by oxidizing gas generated by ozone molecules in the air, ultraviolet rays contained in sunlight, or the like. Specifically, an azo group is oxidized in an azo dye, an anthraquinone moiety in the formula (14) in an anthraquinone dye, an anthrapyridone moiety in the formula (15) in an anthrapyridone dye, and a phthalocyanine moiety in the formula (16) in a phthalocyanine dye. Easy to be. Discoloration or fading occurs due to the oxidation of the colored portion.

  On the other hand, flavonoids contain hydroxyl groups that are very easily oxidized and have the property of being easily oxidized by ozone molecules in the air and oxidizing gases generated by light. In flavonoids, it can be considered that these oxidation reactions function as an excellent antioxidant for the dye by proceeding at a higher speed than the oxidation reaction of the coloring portion of the dye. The flavonoids and their glycosides are directly bonded to the dyes, so that the anti-oxidation action of the flavonoids directly functions on these dyes on the recording medium, and as a result, the weather resistance of the ink may be improved. it can. Based on this knowledge, the present invention has been completed.

  The ink for inkjet recording of the present invention is excellent in weather resistance, can store images for a long period of time, and can be obtained at low cost.

  The dye used for the ink jet recording ink of the present invention contains at least one dye selected from the group consisting of azo dyes, anthraquinone dyes, anthrapyridone dyes and phthalocyanine dyes. These dyes have a flavonoid or a group having a glucoside structure as a substituent.

  The flavonoid or its saccharide is easily oxidized by an oxidizing gas activated by ozone or ultraviolet rays in the air, and is introduced into the dye as a substituent and oxidized prior to the coloring portion of the dye. And imparts antioxidant properties to the dye. Flavonoids have a diphenylpropane structure in which two benzene rings are connected by three carbon atoms, and the following formula (17):

It is a general term for compounds having the flavan structure shown in FIG. Examples of flavonoids include chalcones, flavanones, flavones, flavonols, flavonols, flavanols (catechins), isoflavones, and anthocyanins. Those extracted from plants can be used.

  Examples of the flavonoid glycoside include those in which a hydroxyl group of flavonoid and a reducing group of sugar are bonded.

  Specifically, as flavanones, the following formula (18)

Naringenin and its glycoside naringen (rich in savon and buntan peels) and hesperetin and its glycoside hesperidin (rich in lemon peels and juices and orange peels). Can be mentioned.

  As flavonols, the following formula (19)

Quercetin and its glycoside rutin (rich in lettuce, broccoli, apple peel, strawberry, onion, tea, buckwheat), kaempferol (rich in leek, broccoli, radish, onion, and grapefruit) .).

  As flavanols, the following formula (20) containing catechin represented by formula (1) (abundant in green tea and fruits).

Epicatechin (abundantly contained in cacao), epigallocatechin, epicatechin gallate, and epigallocatechin gallate (these are abundant in green tea).

  As anthocyanin, the following formula (21)

Cyanidine and its glycoside cyanine (rich in strawberries, grapes and blueberries), delphinidin and its glycoside delphinin (rich in eggplant skin, grapes and blueberries), pelargonidin And pelargonin which is a glycoside thereof (which is abundant in the flowers of pearl oyster).

  As flavones, the following formula (22)

The apigenin shown in FIG.

  Examples of flavonols include pinobankin, aromadendrin, and fustine. Examples of isoflavones include daidzein and genistein.

  Among these, those having 3 or more hydroxyl groups are more preferable because they can impart strong antioxidant properties to the dye. Furthermore, the catechin represented by Formula (1) can be mentioned as a more preferable thing.

  Such a flavonoid or a group having a glycoside structure thereof may be bonded to the dye at any position of the flavonoid or the glycoside, but the 9-position carbon easily forms a bond with the dye. Is preferable.

  Preferable examples of the dye having a group having the flavonoid or a glycoside structure thereof include the following. As the azo dye, the following formula (2)

The azo compound represented by these can be mentioned. In the formula, R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₂ to R ₅ independently represent a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, Alternatively, a hydrophilic group such as a hydroxyl group is shown.

  Moreover, as an azo dye, following formula (3)

The azo compound represented by these can be mentioned. In the formula, R ₆ represents a flavonoid having two or more hydroxyl groups or a group having a glucoside structure thereof. R ₇ represents a hydrophilic group such as a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, or a hydroxyl group, or a flavonoid having two or more hydroxyl groups or a group having a saccharide structure. R ₈ to R ₁₈ independently represent a hydrophilic group such as a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, or a hydroxyl group .

  Moreover, as an azo dye, following formula (4)

The azo compound represented by these can be mentioned. In the formula, R ₁₈ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof. R ₁₉ represents a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, or a hydrophilic group such as a hydroxyl group, or a flavonoid having two or more hydroxyl groups or a group having a saccharide structure. R ₂₀ to R ₂₄ independently represent a hydrophilic group such as a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, or a hydroxyl group.

  As an anthraquinone dye, the following formula (5)

The anthraquinone compound represented by these can be mentioned. In the formula, R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure, and R ₂ and R ₃ are independently a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, Alternatively, it represents a hydrophilic group such as a hydroxyl group or a phenyl group.

  Moreover, as anthraquinone dye, following formula (6)

The anthraquinone compound represented by these can be mentioned. In the formula, R ₄ represents a flavonoid having two or more hydroxyl groups or a group having a glucoside structure thereof, and R ₅ to R ₇ are independently a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, Alternatively, it represents a hydrophilic group such as a hydroxyl group or a phenyl group.

  Moreover, as anthraquinone dye, following formula (7)

The anthraquinone compound represented by these can be mentioned. In the formula, R ₈ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure, and R ₉ to R ₁₁ independently represent a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, Alternatively, it represents a hydrophilic group such as a hydroxyl group or a phenyl group.

  As an anthrapyridone dye, the following formula (8)

The anthrapyridone compound represented by these can be mentioned. In the formula, R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure, and R ₂ and R ₃ are independently a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, Alternatively, it represents a hydrophilic group such as a hydroxyl group or a phenyl group.

  Moreover, as an anthrapyridone dye, following formula (9)

The anthrapyridone compound represented by these can be mentioned. In the formula, R ₅ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₆ to R ₈ independently represent a hydrogen atom, an alkyl group; a hydroxyl group, a sulfone group, an amino group, a carbonyl group. A hydrophilic group such as a group or a carboxyl group, or a phenyl group;

  As the phthalocyanine dye, the following formula (10)

The phthalocyanine compound represented by these can be mentioned. In the formula, Pc represents a phthalocyanine group having Cu ions or Mg ions, and R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure. R ₂ to R ₅ independently represent a hydrogen atom, an alkyl group; a hydrophilic group such as a hydroxyl group, a sulfone group, an amino group, a carbonyl group, or a carboxyl group, or a phenyl group, and n is 1 to 3 Indicates any integer.

  Moreover, as a phthalocyanine dye, following formula (11)

The phthalocyanine compound represented by these can be mentioned. In the formula, Pc represents a phthalocyanine group having Cu ions or Mg ions. R ₆ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure, and R ₇ to R ₁₁ are independently a hydrogen atom, an alkyl group; a hydroxyl group, a sulfone group, an amino group, a carbonyl group, or A hydrophilic group such as a carboxyl group is shown.

  Further, as the phthalocyanine dye, the following formula (12)

The phthalocyanine compound represented by these can be mentioned. In the formula, Pc represents a phthalocyanine group having Cu ions or Mg ions, and R ₁₂ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure. R ₁₃ to R ₁₆ are independently a hydrogen atom, an alkyl group; a hydrophilic group such as a hydroxyl group, a sulfone group, an amino group, a carbonyl group, or a carboxyl group, or a flavonoid having two or more hydroxyl groups or a group thereof. A group having a saccharide structure is shown.

  Even if 1 type of the said dye is used, it can be used in combination of 2 or more type.

  The method disclosed in JP-A-2003-138258 can be used as a method for introducing the functional group of the flavonoid or its glycoside into the dye.

  The content of these dyes in the ink is preferably 1% by mass to 30% by mass, and more preferably 3% by mass to 10% by mass with respect to the total mass of the ink. If the ink content is 1% by mass or more, a sharp image can be obtained. If the ink content is 30% by mass or less, the viscosity of the ink can be made appropriate and good recording can be performed by the ink jet recording head. it can.

  As the solvent used in the ink jet recording ink of the present invention, a water-soluble organic solvent is preferably used. Specifically, the following can be mentioned. Amides such as dimethylformamide and dimethylacetamide. Ketones such as acetone. Ethers such as tetrahydrofuran and dioxane. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol. Alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol Le. Lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether; Monovalent alcohols such as ethanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol; In addition, glycerin, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, triethanolamine, sulfolane, dimethylsulfoxide and the like. These organic solvents can be used alone or in combination of two or more.

  The content of the solvent is preferably 1% by mass to 50% by mass and more preferably 2% by mass to 30% by mass with respect to the total mass of the ink.

  The water-soluble organic solvent is preferably mixed with water in a mass ratio (water-soluble organic solvent: water) in the range of 1: 2 to 1:50.

  In the ink jet recording ink, additives such as a viscosity adjuster, a pH adjuster, a preservative, a surfactant, an antioxidant, an evaporation accelerator, etc., as necessary, as long as the function of the dye is not impaired. Can be blended. Surfactants are particularly important in adjusting the permeability of the liquid. The surfactant can be selected from cationic, anionic, amphoteric and nonionic depending on the type of dye and solvent used. Examples of the surfactant include Surfynol 465 (manufactured by Air Product), acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.), Targitol (manufactured by Union Carbide) and the like. The content of the surfactant is preferably 0.01% by mass or more and 10% by mass or less with respect to the total mass of the ink.

  The ink for ink jet recording is preferably weakly acidic at around 25 ° C., specifically pH of 5-7. The surface tension is preferably 10 to 60 dyn / cm, and the viscosity is preferably 1 to 30 cps.

  In order to prepare the ink for ink jet recording, there may be mentioned a method in which the dye is added to the solvent and dissolved and dispersed. If necessary, a dispersant (surfactant) may be used, and the dye may be finely divided by a disperser and dispersed. Examples of the disperser include a ball mill, a sand mill, an attritor, a roll mill, an agitator mill, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a jet mill, and an ang mill.

  As the recording medium for fixing the ink for ink jet recording of the present invention, paper, cloth, OHP paper, printed circuit board and the like can be applied, but those having an ink absorbing layer are preferable. Specifically, as shown in FIG. 4, one having a porous ink absorbing layer 32 on a base paper 31 can be exemplified. As the base paper, for example, paper made by appropriately adding a paper strength enhancer to pulp can be used. The porous ink absorbing layer can be formed by applying to a base paper using cationized starch or the like.

  In the ink for ink jet recording of the present invention, weather resistance is remarkably improved by using a dye having a group having a flavonoid or saccharide structure. An image formed using this ink can be kept in a good storage state because discoloration and fading are suppressed even after long-term storage.

  An ink jet recording unit of the present invention comprises an ink tank for storing the ink for ink jet recording and an ink jet recording head. As an example of the inkjet recording unit, the one shown in the perspective view of FIG. 1 can be cited. The recording unit H shown in FIG. 1 is provided with an ink tank 21 that stores the ink for ink jet recording and an ink jet recording head (not shown) having an ink discharge section. For example, the ink ejection units are provided for each color ink of yellow, magenta, cyan, and black. The ink ejection section is provided with a plurality of ejection openings for ejecting ink, and the openings of the ejection openings are arranged to face the recording medium, and the ink is ejected based on the recording data to form an image. It has become.

  As an ink discharge method, any discharge method using thermal energy, mechanical energy, or the like may be used.

  An ink jet recording apparatus that includes such a recording unit and forms an image will be described below with reference to a schematic external view of FIG. 2 and a schematic internal configuration diagram of FIG. The ink jet recording apparatus is provided with transport rollers 17 and 18 that sandwich and transport the recording medium 12, and the recording medium 12 taken out from the paper feed tray 1 moves from the transport roller 17 toward the transport roller 18. It is conveyed to the paper discharge tray 2. A drive rail 15 is provided above the conveyance path of the recording medium 12 so as to be orthogonal to the conveyance direction of the recording medium. The recording unit H is recorded on the driving rail and the opening of the ejection port is recorded. A carriage 11 mounted so as to face the medium is supported. A drive belt 14 suspended from a pulley connected to the rotation shaft of the drive motor 13 is connected to the carriage 11. The drive belt 14 moves as the drive motor 13 rotates, and the carriage reciprocates on the drive rail. It is supposed to let you. The operation of the drive motor 13 and a paper passing motor (not shown) for driving the transport roller is controlled by a control circuit (not shown).

  Further, a discharge recovery unit 16 having a discharge recovery pump is provided at a position below the end of the movement path of the carriage 11, and the discharge recovery port is brought into contact with the discharge recovery unit so that the discharge recovery is performed. The pump can be driven to suck ink in the discharge port. When the ink solvent evaporates and the ink in the ejection port thickens, the ink that has been thickened by the ejection recovery section can be sucked to restore the ejection performance of the recording head.

  As a recording method using this ink jet recording apparatus, the drive belt is moved at a predetermined speed by a drive motor, and thereby the carriage is moved along the drive rail. During this time, ink is selectively ejected from the plurality of ejection ports of the recording head at a predetermined timing according to the recording data to form an image having a predetermined width. After the carriage moves to the end of the drive rail and forms an image with a predetermined width, the transport rollers 17 and 18 are rotated so as to correspond to the predetermined width, and the recording medium is transported the same distance as the predetermined width. Thereafter, while moving the carriage on the drive rail in the reverse direction, ink is ejected to form an image. This is repeated to form an image.

The inkjet recording ink of the present invention will be described in more detail, but the technical scope of the present invention is not limited to these. The following “%” indicates “mass%”.
[Example 1]
A water-soluble azo dye having a group having a flavonoid structure was synthesized by the following method.

  As shown in the formula (23), the commercial dye CI Direct Yellow 86 is oxidized by an ordinary method to form an aldehyde group, and then catechin extracted from green tea or the like is condensed with an acid catalyst to form a group having a catechin structure. An azo dye having was synthesized.

  Using the obtained antioxidant azo dye, the following components were mixed and filtered under pressure through a membrane filter having a pore size of 0.22 μm to prepare yellow ink and black ink.

Antioxidant azo dye 2%
Thiodiglycol 10%
Acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.) 0.05%
Water residue The obtained ink was stored in an ink tank of an ink jet recording head, and an image was formed on a recording medium using a serial type ink jet recording apparatus (PIXUS-850i manufactured by Canon Inc.). For image formation, the recording conditions were adjusted so that the OD (Optical Density) was in the range of 0.9 to 1.1, and a single color patch (1.5 cm square) was formed. It was. As the recording medium, the paper shown in FIG. 4 prepared as follows was used.

[recoding media]
After mixing and beating 90 parts of LBKP and 10 parts of NBKP as raw material pulp, 20 parts of calcium carbonate, 0.2 part of alkenyl succinic anhydride and 0.5 part of cationized starch are blended, and the basis weight is 64 g / m. ^2. A base paper having a thickness of 90 μm and a Steecht size of 15 seconds was made. The specific volume of this base paper was 1.4 cm ³ / g. A 6% aqueous solution obtained by mixing cationized starch (CATO304: manufactured by NATIONAL STARCH & CHEMICAL) with water was applied to the obtained base paper as a coating solution, applied to 1.5 g / m ² with a bar coater, and 3% in an oven at 100 ° C. The recording medium was obtained by drying for a minute.

[Weather resistance evaluation]
[Ozone resistance]
Using an ozone weather meter (OMS-H type: manufactured by Suga Test Instruments Co., Ltd.), the sample was exposed to ozone for a predetermined time (6 hours, 12 hours) under the conditions of 24 ° C., humidity 60% and ozone concentration 2 ppm. The samples were observed for discoloration and evaluated for sensitivity according to the following criteria. The results are shown in Table 1.

Evaluation A: 9 or more out of 10 subjects are determined to have no change in image density Evaluation B: 7 or more of 10 subjects are determined to have no change in image density Evaluation C: 5 or more of 10 subjects are determined to have no change in image density Determination Evaluation D: It is determined that 9 or more of 10 subjects have image density changes.

[Light resistance]
After covering the surface of the sample with a colorless glass plate, using a xenon weather meter (XL-75S: manufactured by Suga Test Instruments Co., Ltd.), the sample was exposed for 24 hours at a humidity of 60% for a predetermined time (6 hours, 12 hours). Irradiation conditions were BPT (black panel temperature) 40 ° C .; illuminance 34 W / m ² between 300 and 400 nm. The sample was observed for discoloration, and a sensitivity evaluation was performed according to the same criteria as the ozone resistance evaluation. The results are shown in Table 1.

[Example 2]
As shown in Formula (24), an antioxidant azo dye having a group having a catechin structure was synthesized and an ink was prepared in the same manner as in Example 1 except that the commercial dye CI Direct Black 32 was used. Using this, an image was formed on the recording medium in the same manner as in Example 1, and the weather resistance was evaluated. The results are shown in Table 1.

[Example 3]
An antioxidant azo dye having a group having a catechin structure was synthesized in the same manner as in Example 1 except that the azo dye represented by the formula (25) described in JP-A No. 11-158396 was used. An ink was prepared. Using this, an image was formed on the recording medium in the same manner as in Example 1, and the weather resistance was evaluated. The results are shown in Table 1.

[Comparative Example 1]
The ink was prepared in the same manner as in Example 1, except that 1.6% of the azo dye used as the starting material of Example 1 was used as the azo dye, and 0.4% of catechin was used as the antioxidant separately from the dye. It was prepared, an image was formed on the recording medium using this, and the weather resistance was evaluated. The results are shown in Table 2.

[Comparative Example 2]
The ink was prepared in the same manner as in Example 1 except that 1.4% of the azo dye used as the starting material of Example 2 was used as the azo dye, and 0.6% of catechin was used as the antioxidant separately from the dye. It was prepared, an image was formed on the recording medium using this, and the weather resistance was evaluated. The results are shown in Table 2.

[Comparative Example 3]
The ink was prepared in the same manner as in Example 1 except that 1.1% of the azo dye used as the starting material of Example 3 was used as the azo dye, and 0.9% of catechin was used as the antioxidant separately from the dye. It was prepared, an image was formed on the recording medium using this, and the weather resistance was evaluated. The results are shown in Table 2.

[Comparative Example 4]
An ink was prepared in the same manner as in Example 1 except that 1.6% of the azo dye used as the starting material of Example 1 was used as the azo dye, and this was used to form an image on a recording medium. Evaluation was performed. The results are shown in Table 2.

[Comparative Example 5]
An ink was prepared in the same manner as in Example 1 except that 1.4% of the azo dye used as the starting material of Example 2 was used as the azo dye, and this was used to form an image on a recording medium. Evaluation was performed. The results are shown in Table 2.

[Comparative Example 6]
An ink was prepared in the same manner as in Example 1 except that 1.1% of the azo dye used as the starting material of Example 3 was used as the azo dye, and this was used to form an image on a recording medium. Evaluation was performed. The results are shown in Table 2.

[Example 4]
A water-soluble anthraquinone dye having a group having a flavonoid structure was synthesized by the following method.

  As shown in formula (26), except that 1-hydroxy-anthraquinone-2-carboxaldehyde was used, an antioxidant anthraquinone dye was synthesized in the same manner as in Example 1, and a magenta ink was prepared using this. did. An image was formed on a recording medium using the obtained ink in the same manner as in Example 1, and the weather resistance was evaluated. The results are shown in Table 3.

[Example 5]
As shown in Formula (27), a commercially available anthraquinone dye having a carboxyl group was reduced together with LiAlH _{4 by a} conventional method (described in Japanese Patent Publication No. 7-37585) to form an aldehyde group. Catechin extracted from green tea or the like was condensed with an acid catalyst to synthesize an antioxidant anthraquinone dye having a group having a catechin structure. Using this, an ink was prepared in the same manner as in Example 1, an image was formed on a recording medium, and the weather resistance was evaluated. The results are shown in Table 3.

[Example 6]
As shown in formula (28), a commercially available anthraquinone dye having a carboxyl group was reduced together with LiAlH _{4 by a} conventional method (described in JP-B-6-011869) to form an aldehyde group. Catechin extracted from green tea or the like was condensed with an acid catalyst to synthesize an antioxidant anthraquinone dye having a group having a catechin structure. Using this, an ink was prepared in the same manner as in Example 1, an image was formed on a recording medium, and the weather resistance was evaluated. The results are shown in Table 3.

[Comparative Example 7]
As an anthraquinone dye, 0.9% of 1-hydroxy-anthraquinone-2-carboxaldehyde used as a starting material in Example 4 was used, and 1.1% of catechin as an antioxidant was used separately from the dye. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 4.

[Comparative Example 8]
As an anthraquinone dye, 1.2% of the anthraquinone dye used as a starting material of Example 5 was used, and 0.8% of catechin as an antioxidant was used separately from the dye. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using this ink, and the weather resistance was evaluated. The results are shown in Table 4.

[Comparative Example 9]
As the anthraquinone dye, 1.2% of the anthraquinone dye used as the starting material of Example 6 was used. As an antioxidant, catechin 0.8% was used separately from the dye. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 4.

[Comparative Example 10]
As the anthraquinone dye, 0.9% of the anthraquinone dye used as the starting material of Example 4 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 4.

[Comparative Example 11]
As the anthraquinone dye, 1.2% of the anthraquinone dye used as the starting material of Example 5 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 4.

[Comparative Example 12]
As the anthraquinone dye, 1.2% of the anthraquinone dye used as the starting material of Example 6 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 4.

[Example 7]
A water-soluble anthrapyridone dye having a group having a flavonoid structure was synthesized by the following method.

  First, as shown in formula (29), the hydroxyl group of 3-aminobenzyl alcohol was protected with TBSCl (t-butyldimethylsilyl chloride).

  Next, as shown in the formula (30), benzoylacetic acid ethyl ester was reacted with an anthrapyridone compound in a polar solvent such as xylene.

  And as shown to Formula (31), after making this react 3-hydroxybenzyl alcohol which protected the hydroxyl group, the hydroxyl group was deprotected using the acid, and the anthrapyridone compound was obtained.

  Further, as shown in the formula (32), this anthrapyridone compound was oxidized by a conventional method to make a hydroxyl group an aldehyde group. Catechin extracted from green tea or the like was condensed under an acid catalyst to synthesize an antioxidant anthrapyridone dye having a group having a catechin structure.

  A magenta ink was prepared in the same manner as in Example 1 except that the obtained antioxidant anthrapyridone dye having a group having a catechin structure was used. Using this, an image was formed on a recording medium in the same manner as in Example 1, and the weather resistance was evaluated. The results are shown in Table 5.

[Example 8]
As shown in Formula (33), a commercially available anthrapyridone dye having a carboxyl group was reduced together with LiAlH _{4 by a} conventional method (described in JP-A No. 2000-109464) to form an aldehyde group. Catechin extracted from green tea or the like was condensed under an acid catalyst to synthesize an antioxidant anthrapyridone dye having a group having a catechin structure. Using this, an ink was prepared in the same manner as in Example 1, an image was formed on a recording medium, and the weather resistance was evaluated. The results are shown in Table 5.

[Comparative Example 13]
An ink was prepared in the same manner as in Example 1 except that 1.3% of the anthrapyridone compound prepared in Example 7 was used as the anthrapyridone dye and 0.7% of catechin was used as the antioxidant separately from the dye. Then, an image was formed on the recording medium using this, and the weather resistance was evaluated. The results are shown in Table 6.

[Comparative Example 14]
As the anthrapyridone dye, 1.4% of the anthrapyridone compound used as a starting material in Example 8 was used, and 0.6% of catechin was used as an antioxidant separately from the dye. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 6.

[Comparative Example 15]
As an anthrapyridone dye, 1.3% of an anthrapyridone compound of the formula (35) used as a starting material of Comparative Example 13 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using this ink, and the weather resistance was evaluated. The results are shown in Table 6.

[Comparative Example 16]
As the anthrapyridone dye, 1.4% of the anthrapyridone compound used as the starting material of Example 8 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using this ink, and the weather resistance was evaluated. The results are shown in Table 6.

[Example 9]
A water-soluble phthalocyanine dye having a group having a flavonoid structure was synthesized by the following method.

First, as shown in Formula (34), a carboxyl group was introduced into a benzene ring using copper phthalocyanine, an oxalyl chloride catalyst, and an AlCl ₃ catalyst to obtain a phthalocyanine compound.

  Next, a part of the carboxyl group was reduced according to a conventional method to obtain an aldehyde group. This was condensed with BHT in the presence of an acid catalyst to obtain an antioxidant phthalocyanine dye having a functional group related to BHT. A cyan ink was prepared in the same manner as in Example 1 except that this was used. Using this, an image was formed on the recording medium in the same manner as in Example 1, and the weather resistance was evaluated. The results are shown in Table 7.

[Example 10]
As shown in Formula (35), a commercially available phthalocyanine dye having a carboxyl group was reduced by a conventional method (described in Japanese Patent Publication No. 4-10509) using LiAlH ₄ to convert the carboxyl group into an aldehyde group. Catechin extracted from green tea or the like was condensed with an acid catalyst to synthesize an antioxidant phthalocyanine dye having a group having a catechin structure. Using this, an ink was prepared in the same manner as in Example 1, an image was formed on a recording medium, and the weather resistance was evaluated. The results are shown in Table 7.

[Example 11]
As shown in Formula (36), a commercially available phthalocyanine dye having a carboxyl group was reduced by a conventional method (described in JP-A-5-239368) using LiAlH ₄ to convert the carboxyl group to an aldehyde group. Catechin extracted from green tea or the like was condensed with an acid catalyst to synthesize an antioxidant phthalocyanine dye having a group having a catechin structure. Using this, an ink was prepared in the same manner as in Example 1, an image was formed on a recording medium, and the weather resistance was evaluated. The results are shown in Table 7.

[Comparative Example 17]
As the phthalocyanine dye, 1.4% of the copper phthalocyanine compound having three carboxyl groups prepared in Example 9 was used, and 0.6% of catechin was used as an antioxidant separately from the dye. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 8.

[Comparative Example 18]
As the phthalocyanine dye, 1.7% of the phthalocyanine compound used as a starting material of Example 10 was used, and 0.3% of catechin as an antioxidant was used separately from the dye. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 8.

[Comparative Example 19]
As the phthalocyanine dye, 1.3% of the phthalocyanine compound used as the starting material of Example 11 was used, and 0.7% of catechin was used as an antioxidant separately from the dye. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 8.

[Comparative Example 20]
As the phthalocyanine dye, 1.4% of a copper phthalocyanine compound having three carboxyl groups prepared in Example 9 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 8.

[Comparative Example 21]
As the phthalocyanine dye, 1.7% of the phthalocyanine compound used as the starting material of Example 10 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using the ink, and the weather resistance was evaluated. The results are shown in Table 8.

[Comparative Example 22]
As the phthalocyanine dye, 1.3% of the phthalocyanine compound used as the starting material of Example 11 was used. Other than that, an ink was prepared in the same manner as in Example 1, and an image was formed on the recording medium using this ink, and the weather resistance was evaluated. The results are shown in Table 8.

  As a result of recording using the ink for ink jet recording of the present invention, an image having excellent weather resistance such as ozone resistance and light resistance was obtained.

It is a schematic perspective view which shows an example of the inkjet recording unit of this invention. It is a schematic perspective view which shows an example of the inkjet recording device of this invention. It is a schematic block diagram which shows an example of the inkjet recording device of this invention. It is a schematic sectional drawing which shows an example of the recording medium which forms an image using the ink for inkjet recording of this invention.

Explanation of symbols

21 Ink tank H Inkjet recording unit

Claims (15)

An inkjet recording ink containing at least one dye selected from the group consisting of an azo dye, an anthraquinone dye, an anthrapyridone dye, and a phthalocyanine dye,
The ink for ink jet recording, wherein the dye has a flavonoid or a group having a saccharide structure.   2. The ink for ink jet recording according to claim 1, wherein the flavonoid or a group having a saccharide structure thereof has 3 or more hydroxyl groups. Flavonoid is represented by the following formula (1)

The ink for inkjet recording according to claim 2, wherein A flavonoid or a dye having a saccharide structure thereof is represented by the following formula (2):

(In the formula, R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₂ to R ₅ independently represent a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group. Or an hydroxyl group.) The inkjet recording ink according to claim 1, wherein the ink is an azo dye represented by the formula: A flavonoid or a dye having a saccharide structure is represented by the following formula (3):

(In the formula, R ₆ represents a flavonoid having two or more hydroxyl groups or a group having a glucoside structure, and R ₇ represents a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, a hydroxyl group, or a hydroxyl group. A group having at least one flavonoid or a saccharide structure thereof, and R ₈ to R ₁₈ independently represent a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, or a hydroxyl group. The ink for inkjet recording according to any one of claims 1 to 3, wherein the ink is an azo dye. A flavonoid or a dye having a saccharide structure is represented by the following formula (4):

(In the formula, R ₁₈ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₁₉ represents a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, a hydroxyl group, or a hydroxyl group. A group having at least one flavonoid or a group having a glycoside structure thereof, wherein R ₂₀ to R ₂₄ independently represent a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group, or a hydroxyl group. The ink for inkjet recording according to any one of claims 1 to 3, wherein the ink is an azo dye. A flavonoid or a dye having a saccharide structure is represented by the following formula (5):

(In the formula, R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₂ and R ₃ are independently a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group. Ink jet recording ink according to any one of claims 1 to 3, which is an anthraquinone dye represented by the formula: A flavonoid or a dye having a saccharide structure thereof is represented by the following formula (6):

(Wherein R ₄ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₅ to R ₇ independently represent a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group. Ink jet recording ink according to any one of claims 1 to 3, which is an anthraquinone dye represented by the formula: A flavonoid or a dye having a saccharide structure thereof is represented by the following formula (7):

(In the formula, R ₈ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₉ to R ₁₁ independently represent a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group. Ink jet recording ink according to any one of claims 1 to 3, which is an anthraquinone dye represented by the formula: A flavonoid or a dye having a saccharide structure is represented by the following formula (8):

(In the formula, R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₂ and R ₃ are independently a hydrogen atom, a sulfone group, a carboxyl group, an aldehyde group, an amino group. Inkjet recording ink according to any one of claims 1 to 3, which is an anthrapyridone dye represented by the formula: A flavonoid or a dye having a saccharide structure is represented by the following formula (9):

(In the formula, R ₅ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₆ to R ₈ independently represent a hydrogen atom, an alkyl group, a hydroxyl group, a sulfone group, an amino group, The ink for inkjet recording according to any one of claims 1 to 3, wherein the ink is an anthrapyridone dye represented by a carbonyl group, a carboxyl group, or a phenyl group. A flavonoid or a dye having a saccharide structure is represented by the following formula (10):

(Wherein Pc represents a phthalocyanine group having Cu ion or Mg ion, R ₁ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₂ to R ₅ are independently A hydrogen atom, an alkyl group, a hydroxyl group, a sulfone group, an amino group, a carbonyl group, a carboxyl group, or a phenyl group, and n represents an integer of 1 to 3.) The ink for inkjet recording according to any one of claims 1 to 3. A flavonoid or a dye having a saccharide structure thereof is represented by the following formula (11):

(Wherein Pc represents a phthalocyanine group having Cu ions or Mg ions, R ₆ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₇ to R ₁₁ are independently 4. A phthalocyanine dye represented by a hydrogen atom, an alkyl group, a hydroxyl group, a sulfone group, an amino group, a carbonyl group, or a carboxyl group. ink. A flavonoid or a dye having a saccharide structure thereof is represented by the following formula (12):

(Wherein Pc represents a phthalocyanine group having Cu ions or Mg ions, R ₁₂ represents a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof, and R ₁₃ to R ₁₆ are independently A hydrogen atom, an alkyl group, a hydroxyl group, a sulfone group, an amino group, a carbonyl group, a carboxyl group, or a flavonoid having two or more hydroxyl groups or a group having a saccharide structure thereof). The ink for inkjet recording according to any one of claims 1 to 3.   An ink jet recording unit comprising an ink tank and an ink jet recording head for accommodating the ink for ink jet recording according to claim 1.

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