JPH0841398A - Ink jet recording liquid - Google Patents

Abstract

PURPOSE:To provide an ink jet ink capable of pH retention for a long period of time, high in coloring material dissolution stability, not causative of nozzle clogging, and capable of securing a sufficient amt. of ejection. CONSTITUTION:An ink comprising a coloring material and a liq. medium capable of dissolving the coloring material contains at least one compd. selected from among 2-(cyclohexylamino)ethanesulfonic acid, 3-N-cyclohexylamino-2- hydroxypropanesulfonic acid, 3-N-cyclohexylaminopropanesulfanic acid and glycine, and a hydroxide or carbonate of an alkali metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording liquid (hereinafter referred to as ink) used for ink jet recording, and particularly to a method of applying thermal energy to ink and ejecting droplets by expansion force of generated bubbles (bubble jet). Method).

[0002]

2. Description of the Related Art Conventionally, many inkjet inks containing a pH buffer are known. Examples of the pH buffer agent include sodium borate and N-tris (hydroxy) methyl-2 in JP-A-4-226175.
-Aminoethanesulfonic acid, N, N-bis (2-hydroxyethyl) glycine, triethanolamine and tris (hydroxymethyl) aminoethane are mentioned.

As an example of a typical liquid medium for ink jet ink, Japanese Patent Laid-Open No. 57-74372 discloses glycerin, 10 to 40% by weight of ethylene glycol, and 1 to
A combination of 20% by weight of urea is disclosed in JP-A-1-1185.
No. 83 discloses a combination of a polyhydric alcohol, an aliphatic monohydric alcohol and water; JP-A-2-167772 describes a combination of a urea, an aliphatic monohydric alcohol and water;
JP-A-4-226175 discloses a combination of pyrrolidone, 2-pyrrolidone and diethylene glycol, respectively.

The ink described in Japanese Patent Application Laid-Open No. 4-226175 is an example in which an ammonium salt type dye having a low solubility is used as a coloring material. In order to obtain a water-resistant printed material, a specific structure is used. Various problems that occur due to the use of a dye (a dye in which the carboxyl group in the molecule is of an ammonium salt type), that is, (1) nozzle clogging, (2) growth of dye crystals from the nozzle to the outside of the nozzle. As a means for solving the problems such as (3) reduction of printed matter concentration due to bronzing of printed matter, (4) nozzle clogging outside the proper ink pH and increased bronzing of printed matter, (1) dyes having different structures The method of mixing and using, and (2) adding a pH buffering agent are mentioned.

[0005]

Many of the conventionally known inks are aimed at maintaining the pH of the ink, improving the solubility of the dye, and improving one of the various other required performances. It was

For example, in the ink composition disclosed in JP-A-4-226175, the pH of the ink is 8-9.
However, the effect of preventing the occurrence of nozzle clogging was not sufficient. Further, the print density was insufficient because a sufficient nozzle discharge amount could not be obtained. Although the reason is not clear, when an ammonium salt type dye is used, the ejection amount of the ink tends to be small, and particularly when the dissociative group in the dye is a carboxyl group, this tendency is remarkable. For example, the discharge amount may be less than 60% of the case where the Na salt type dye having the same structure is used. In order to increase the ejection amount, it is possible to adopt a means for increasing the input energy, but this causes problems such as an increase in power consumption, heat generation, and acceleration of ink evaporation rate.

In addition, it is difficult to maintain pH with a generally known ink jet ink composition.
There is a big problem in using a water resistant dye that utilizes H dependency. On the other hand, in the ink containing urea,
The pH tends to be maintained, but the discharge amount is not sufficient.

Therefore, an object of the present invention is to provide an ink jet ink which can maintain a pH for a long period of time, has a high stability of dye dissolution, does not cause nozzle clogging, and can obtain a sufficient discharge amount. To provide.

[0009]

The above object can be achieved by the present invention described below. That is, the present invention provides an ink comprising a coloring material and a liquid medium that dissolves the coloring material, wherein the ink contains
2- (cyclohexylamino) ethanesulfonic acid, 3-
An inkjet characterized by containing at least one compound selected from N-cyclohexylamino-2-hydroxypropanesulfonic acid, 3-N-cyclohexylaminopropanesulfonic acid and glycine and an alkali metal hydroxide or carbonate. Ink.

Further, the present invention is an ink jet ink characterized in that, in the ink having the above constitution, the coloring material is a dye represented by the following general formula (I). [In the general formula (I), W and X each represent H, COOM or SO ₃ M, and M represents NH ₄ . ]

[0011]

According to the present invention, it is possible to obtain an ink suitable for a system (bubble jet system) in which thermal energy is given to the ink and the expansion force of the generated bubbles ejects the liquid droplets. That is, at least one compound selected from 2- (cyclohexylamino) ethanesulfonic acid, 3-N-cyclohexylamino-2-hydroxypyropansulfonic acid, 3-N-cyclohexylaminopropanesulfonic acid, and glycine in the ink. By including a hydroxide or carbonate of an alkali metal, it is possible to increase the ejection amount of ink and to efficiently use heat energy. Further, it is possible to maintain the pH of the ink, maintain the dissolution stability of the dye, and sufficiently prevent the nozzle from clogging.

The effects of increasing the amount of ejected ink, maintaining pH and preventing nozzle clogging are remarkable when only one of the dyes of the following general formula (I) is used as a coloring material.
That is, when an ink is prepared with a conventionally known composition by using one of the dyes of the following general formula (I), the ejection amount is small, the nozzle is clogged, and the pH is lowered. The ink composition of the present invention improves these points. [In the general formula (I), W and X each represent H, COOM or SO ₃ M, and M represents NH ₄ ].

It is industrially very beneficial to be able to use only one type of coloring material. In other words, the development of new dyes is currently underway in order to obtain the desired performance, but when using new dyes, it takes enormous time and cost to register the chemical substance, and a single color material is used. If the desired performance can be achieved, the economic benefit will be immeasurable.

[0014]

Preferred Embodiments Next, preferred embodiments will be described.
The present invention will be described in more detail. As the coloring material used in the ink of the present invention, the dye represented by the general formula (I) is particularly preferably used, but an ammonium salt type dye other than the general formula (I) is also suitable. Ammonium salt type dyes
For example, it is synthesized and ammonium chloride is added by the method described in JP-A-4-226175. The use of these ammonium salt type dyes improves the water resistance of the printed matter. In the present invention, the dye is used in the range of 1 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of the ink. If it is less than 1% by weight, the print density of the printed matter is insufficient, while if it exceeds 10% by weight, the deposition of dye,
This is not preferable because it causes problems such as nozzle clogging or insufficient discharge.

In the present invention, in order to make up for the insufficient discharge amount due to these dyes, 2- (cyclohexylamino) ethanesulfonic acid, 3-N-cyclohexylamino-2-hydroxypropanesulfonic acid, 3-N is added to the ink. −
It contains at least one compound selected from cyclohexylaminopropanesulfonic acid and glycine. The content of these compounds is preferably in the range of 0.1 to 2% by weight, more preferably 0.2 to 1% by weight. When the content of these compounds is less than 0.1% by weight, the ink p
H tends to fluctuate, and the problems of deposition of dye and insufficient amount of ink discharged from the nozzle cannot be solved. On the other hand, 2% by weight
When it exceeds the above range, the pH of the ink is excessively lowered and the amount of the alkaline agent used later for adjusting the pH increases, which is not preferable.

The pH of the ink of the present invention is 8.5-10.
It is adjusted to the range of 5. An alkali metal hydroxide or carbonate is used for pH adjustment. Particularly suitable pH adjusters include sodium hydroxide and lithium hydroxide.

The liquid medium used in the ink of the present invention contains water and a mixture of water and a water-soluble organic solvent, and the amount of the water-soluble organic solvent is 5 to 30% by weight, preferably 7% based on the total amount of the ink. 0.5 to 20% by weight.

Preferred water-soluble organic solvents include glycerin, ethylene glycol, thiodiethanol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 2-pyrrolidone, N-methylpyrrolidone-2-one and 1,3-dimethyl. Examples include imidazolin-2-one. One or more of these water-soluble organic solvents are mixed with water and used.

In addition, urea may be added as a moisturizer / dissolution aid for inks and dyes. Further, an alkanolamine typified by triethanolamine may be added as a dissolution aid. In addition, if necessary, an antifungal agent may be added to suppress the generation of mold, and a chelating agent or the like may be added to prevent nozzle clogging and kogation.

The ink of the present invention is particularly suitable for use in an ink jet recording method in which droplets are ejected by the action of heat energy for recording, but it can also be used for other ink jet recording methods and general writing instruments.

As a recording method and apparatus suitable for recording using the ink of the present invention, an ink jet which gives thermal energy corresponding to a recording signal to the ink in the chamber of the recording head and generates a droplet by the energy. The recording method and apparatus are mentioned. Hereinafter, such an inkjet recording device will be described.

FIG. 1 and FIG. 2 show an example of the head structure, which is the main part of the structure. FIG. 1 is a schematic cross-sectional view of the head 13 along the ink flow path, and FIG. 2 is a schematic cross-sectional view showing a cross-sectional view taken along the line AB of FIG. The head 13 has a groove 1 through which ink passes.
It is obtained by adhering a glass, ceramics or a plastic plate having No. 4 and a heating head 15 (a thin film head is shown in the drawing, but not limited to this) used for thermal recording. The heating head 15 includes a protective film 16 made of silicon oxide and an aluminum electrode 17.
-1 and 17-2, a heating resistor layer 18 formed of nichrome, a heat storage layer 19, and a substrate 2 having good heat dissipation such as alumina.
It consists of zero.

The ink 21 is a discharge orifice (fine hole) 2
It is filled up to 2, and a meniscus 23 is formed by a pressure (not shown). Now, when an electric signal is applied to the electrodes 17-1 and 17-2, the area indicated by n of the heating head 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact therewith, and the meniscus 23 is generated by the pressure. Is ejected, the ink 21 is ejected, and the ink droplet 2 is ejected from the ejection orifice 22.
4 and fly toward the recording material 25. Also, FIG.
FIG. 1 shows an example of a multi-head in which many heads shown in FIG. 1 are arranged. The multi-head is made by bonding a glass plate 27 having multi-grooves 26 and a heating head 28 similar to that described in FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 4, reference numeral 65 denotes a recording head having ejection energy generating means, which ejects ink to a recording material facing the ejection port surface where the ejection ports are arranged to perform recording, and 66 denotes a recording head 65 mounted on the recording head. It is a carriage for moving. The carriage 66 has a guide shaft 6
7, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move in the recording area and the area adjacent thereto.

Reference numeral 51 designates a paper feeding section for inserting a recording material, and 5
A paper feed roller 2 is driven by a motor (not shown). With such a configuration, the recording material is fed to a position facing the ejection port surface of the recording head 65, and as recording progresses, the recording material is ejected to the ejection unit provided with the ejection roller 53.

Reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member to become a fixed end, which is in the form of a cantilever (not shown). The blade 61 is arranged at a position adjacent to the recording area of the recording head 65, and in the case of this example, it is held in a protruding form in the movement path of the recording head 65. Reference numeral 62 denotes a discharge port cap of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, and comes into contact with the ink discharge port surface for capping. It has a configuration to do. Further, 63 is an ink absorber provided adjacent to the blade 61, and like the blade 61, is held in a form protruding in the movement path of the recording head 65. The blade 61 and the cap 6
2. The ink absorber 63 constitutes the ejection recovery unit 64, and the blade 61 and the ink absorber 63 remove water, dust, and dust on the ink ejection port surface.

In the above structure, when the recording head 65 returns to the home position after recording is completed, the cap 62 of the ejection recovery unit 64 is retracted from the movement path of the recording head 65, but the blade 61 is projected into the movement path. ing. As a result, the ejection port surface of the recording head 65 is wiped. When the cap 62 comes into contact with the ejection port surface of the recording head 65 to perform capping, the cap 62 moves so as to project into the movement path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are in the same position as the above-mentioned position during wiping. As a result, even during this movement, the ejection port surface of the recording head 65 is wiped. Recording head 65 described above
Is moved to the home position adjacent to the recording area at a predetermined interval while the recording head 65 is moving in the recording area for recording, not only when the recording is completed or when the ejection is recovered. The wiping is performed along with the movement.

FIG. 5 shows a head having a recording supply member, for example,
FIG. 4 is a diagram showing an example of an ink cartridge 45 containing ink supplied via a tube. Here, 40 is an ink containing portion containing the ink for supply, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof. By inserting a needle (not shown) into this stopper 42,
The ink in the ink bag 40 can be supplied to the head. An ink absorber 44 receives the waste ink. In the present invention, it is preferable that the liquid contact surface of the ink containing portion with the ink is formed of polyolefin, particularly polyethylene.

The ink jet recording apparatus in which the ink of the present invention is used is not limited to the above-described head and ink cartridge as separate bodies, but those in which they are integrated as shown in FIG. Is also preferably used. In FIG. 6, reference numeral 70 denotes a recording unit (inkjet cartridge) in which an ink absorber impregnated with ink is stored, and the ink in the ink absorber has a head portion 71 having a plurality of orifices. It is configured to be ejected as an ink droplet from. Polyurethane is preferable as the material of the ink absorber.

Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The inkjet cartridge 70 is used in place of the recording head 65 shown in FIG. 6, and is detachable from the carriage 66.

[0032]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. In the text, "%" is based on weight unless otherwise specified. Example 1 2- (Cyclohexylamino) ethanesulfonic acid 0.6% -Pyrrolidone 10% -Dye of the following formula (A) 2.5% -Water 86.8%

The ingredients of the above formulation are mixed. In mixing, first, 2- (cyclohexylamino) ethanesulfonic acid is weighed, water is added thereto, and neutralized and dissolved with a 10% aqueous solution of sodium hydroxide. The rest of the ingredients were added to this, and finally the pH was adjusted with a 10% aqueous solution of sodium hydroxide.
To the desired value. Then, the ink of the present invention was produced by filtering with a 0.2 μm triacetyl cellulose membrane filter.

Example 2 3-N-cyclohexylamino-2-hydroxypropanesulfonic acid 0.7% -Diethylene glycol 10% -Dye of the formula (A) 2.5% -Water 86.8% Material of the above formulation Thus, the ink of the present invention was prepared in the same manner as in Example 1.

Example 3 3-N-cyclohexylaminopropanesulfonic acid 1.0% Diethylene glycol 10% Dye of the following formula (B) 2.5% Water 86.8% Using the material of the above formulation, an example was obtained. An ink of the present invention was prepared in the same manner as in 1.

Example 4 Glycine 0.4% Ethylene glycol 10% Dye of the formula (B) 2.5% Water 87.2% The present invention was carried out in the same manner as in Example 1 by using the materials of the above formulation. An ink was prepared.

Example 5 2- (Cyclohexylamino) ethanesulfonic acid 0.3% -Glycerin 5% -Ethylene glycol 7% -Urea 5% -Ethanol 5% -Dye of the formula (A) 3% -Water 75 0.7% An ink of the present invention was produced in the same manner as in Example 1 using the materials of the above formulation.

Example 6 3-N-cyclohexylamino-2-hydroxypropanesulfonic acid 0.4% Diethylene glycol 10% Glycerin 5% Urea 3% Isopropyl alcohol 4% Dye 3 of the formula (B) 0.5% water 74.1% An ink of the present invention was produced in the same manner as in Example 1 using the materials having the above formulations.

Example 7 -Glycine 0.2% -Glycerin 5% -Ethylene glycol 5% -Urea 5% -Ethanol 6% -Dye of the above formula (A) 2% -Water 76.8% An ink of the present invention was prepared in the same manner as in Example 1.

Comparative Example 1 -Diethylene glycol 10% -Dye of the formula (A) 2.5% -Water 87.1% Example except that the buffer and sodium hydroxide were not added by the materials of the above formulation. An ink of Comparative Example was prepared in the same manner as in 1.

COMPARATIVE EXAMPLE 2 2-Pyrrolidone 10% Dye of the formula (A) 2.5% Water 87.1% Except that no buffering agent or sodium hydroxide was added by the materials of the above formulation. An ink of Comparative Example was prepared in the same manner as in Example 1.

Comparative Example 3 N-tris (hydroxymethyl) -2-aminoethanesulfonic acid 0.4% Diethylene glycol 10% Dye of the formula (B) 2.5% Water 87.1% After adding sodium hydroxide depending on the material, an ink of a comparative example was prepared in the same manner as in Example 1.

[Evaluation] Each ink of Examples 1 to 7 and Comparative Examples 1 to 3 was filled in an ink container (cartridge) equipped with a bubble jet type ink jet recording head, and the following characteristics were evaluated. The evaluation results are shown in Table 1 below.

(Characteristic 1) Ink discharge amount The weight of a cartridge before and after printing a predetermined pattern is measured by a printer, and the discharge amount per one drop is calculated.

(Characteristic 2) Recoverability After printing with a printer, the ink container with head is removed from the printer and left to stand. After 5 days, print again on the printer and compare the print quality before and after leaving. Count the number of recovery operations required to return to the initial print quality.

(Characteristic 3) pH buffer maintaining ability The ink is stored at 60 ° C for 1 week, and the pH before and after the storage is measured.

Table 1: Evaluation results of Examples 1 to 7 and Comparative Examples 1 to 3

[0048]

According to the present invention, the pH of the ink is maintained for a long period of time by using a specific pH buffering agent, the dissolution stability of the dye is high, the nozzle is not clogged, and sufficient ink is obtained. It is possible to provide an inkjet ink capable of obtaining a discharge amount of

[0049]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a recording head according to an inkjet recording method of the present invention.

FIG. 2 is a schematic cross-sectional view showing a sectional view taken along the line AB of FIG.

FIG. 3 is a schematic cross-sectional view showing an example of a multi-head in which many heads of FIG. 1 are arranged.

FIG. 4 is a schematic perspective view showing an example of an inkjet recording apparatus incorporating the head of FIG.

5 is a schematic cross-sectional view showing an example of an ink cartridge that supplies ink to the head of FIG.

6 is a schematic external view showing an example of a main part of an inkjet recording apparatus in which the head of FIG. 1 and the same ink cartridge are integrated.

[0050]

[Explanation of symbols]

 13: Head 14: Ink Grooves 15 and 28: Heating Head 16: Protective Film 17: Aluminum Electrode 18: Heating Resistor Layer 19: Heat Storage Layer 20: Substrate 21: Ink 22: Ejection Orifice (fine Hole) 23: Meniscus 24: Ink droplets 25: Recording material 26: Multi groove 27: Glass plate 40: Ink bag 42: Rubber stopper 44: Ink absorber 45: Ink cartridge 51: Paper feeder 52: Paper feed roller 52: Paper ejection roller 61: Blade 62: Cap 63: Ink Absorber 64: Ejection Recovery Section 65: Recording Head 66: Carriage 67: Guide Shaft 68: Motor 69: Belt 70: Recording Unit 71: Head Section 72: Atmosphere Communication Port

Front Page Continuation (72) Inventor Osamu Nishiwaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiko Tonogaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. A recording liquid comprising a coloring material and a liquid medium in which the coloring material is dissolved, wherein 2- (cyclohexylamino) ethanesulfonic acid and 3-N-cyclohexylamino-2-hydroxypropane are contained in the recording liquid. An inkjet recording liquid comprising at least one compound selected from sulfonic acid, 3-N-cyclohexylaminopropanesulfonic acid and glycine, and an alkali metal hydroxide or carbonate. 2. The ink jet recording liquid according to claim 1, wherein the compounds contained in the recording liquid are 2- (cyclohexylamino) ethanesulfonic acid and sodium hydroxide or lithium hydroxide. 3. The compound contained in the recording liquid is 3-N-
The inkjet recording liquid according to claim 1, which is cyclohexylamino-2-hydroxypropanesulfonic acid and sodium hydroxide or lithium hydroxide. 4. The compound contained in the recording liquid is 3-N-
The inkjet recording liquid according to claim 1, which is cyclohexylaminopropanesulfonic acid and sodium hydroxide or lithium hydroxide. 5. The ink jet recording liquid according to claim 1, wherein the compounds contained in the recording liquid are glycine and sodium hydroxide or lithium hydroxide. 6. A recording liquid comprising a coloring material and a liquid medium in which the coloring material is dissolved, wherein 2- (cyclohexylamino) ethanesulfonic acid and 3-N-cyclohexylamino-2-hydroxypropane are contained in the recording liquid. At least one compound selected from sulfonic acid, 3-N-cyclohexylaminopropanesulfonic acid and glycine, and an alkali metal hydroxide or carbonate, wherein the coloring material has the following general formula (I):
An ink jet recording liquid, which is a dye represented by: [In the general formula (I), W and X each represent H, COOM or SO ₃ M, and M represents NH ₄ . ] 7. A liquid medium in which a coloring material is dissolved contains water, at least one glycol selected from glycerin, ethylene glycol, thiodiethanol, diethylene glycol, triethylene glycol, propylene glycol and dipropylene glycol, and urea. The inkjet recording liquid according to claim 6. 8. The ink jet recording liquid according to claim 7, wherein the compounds contained in the recording liquid are 2- (cyclohexylamino) ethanesulfonic acid and sodium hydroxide or lithium hydroxide. 9. The compound contained in the recording liquid is 3-N-
The ink jet recording liquid according to claim 7, which is cyclohexylamino-2-hydroxypropanesulfonic acid and sodium hydroxide or lithium hydroxide. 10. The compound contained in the recording liquid is 3-N
An ink jet recording liquid according to claim 7, which is cyclohexylaminopropanesulfonic acid and sodium hydroxide or lithium hydroxide. 11. The ink jet recording liquid according to claim 7, wherein the compounds contained in the recording liquid are glycine and sodium hydroxide or lithium hydroxide.