JP4994610B2 - Ink, method for reducing burnt adhesion to heater surface of ink jet recording head, ink jet recording method, ink jet recording apparatus, recording unit, and method for extending life of recording head - Google Patents

Description

  The present invention relates to ink, ink for ink jet recording, a method for reducing burnt adhesion to the heater surface of an ink jet recording head, an ink jet recording method, an ink jet recording apparatus, a recording unit, and a method for extending the life of an ink jet recording head.

  Conventionally, various methods have been devised for printing using an ink jet recording method, and among them, for example, an ink jet method in which the ink described in Patent Document 1 is ejected as ink droplets by the action of thermal energy. Since the so-called bubble jet method is very simple, a high-density multi-nozzle is very easy, so high-quality images can be obtained at high speed and at a very low cost, and even on plain paper that does not have a special coating layer. It has the feature that it can be printed. In this method, when the heater of the recording head is rapidly heated, the liquid on the heater generates bubbles and causes a sudden increase in volume. The acting force based on this sudden increase in volume causes the leading end of the recording head. The liquid droplets are ejected and ejected from the nozzles to adhere to the recording material and printing is performed.

  However, in this method, the heater of the recording head is repeatedly heated each time ink is ejected. Therefore, when a large amount of printing is performed, a decomposition product (so-called kogation) of ink may accumulate on the heater surface. When kogation accumulates, thermal energy is not effectively transferred from the heater to the ink, and the amount of ejected droplets and the velocity of the ejected droplets are reduced compared to the initial stage, which affects the image quality. Arise. In this case, it is necessary to replace the recording head in order to continuously obtain high quality printing, and this situation leads to an increase in total printing cost for the user.

  Therefore, in the bubble jet recording system, it is always more and more possible to further reduce the adhesion of kogation on the heater that may cause such a situation and to further extend the life of the recording head. It is one of the important technical issues when we should aim for improvement. As a method for solving this problem, for example, Patent Document 2 proposes an ink containing an oxo anion. Examples of the oxo anion include phosphate, polyphosphate, phosphate ester, arsenate, molybdate, sulfate, sulfite, and oxalate.

However, in such an ink, in the process of repeating ink ejection, these phosphates, polyphosphates, phosphates, arsenates, molybdates, sulfates, sulfites, and oxalates The problem is that the outermost protective film in contact with the ink made of metal such as tantalum and / or metal oxide formed on the heating resistor is dissolved and the heater is disconnected, thereby making it impossible to discharge ink. There is. In addition, the ability to prevent kogation adhesion is insufficient.
JP 54-51837 A Japanese Patent Laid-Open No. 3-160070

  Accordingly, an object of the present invention is to further reduce the adhesion of kogation to the heater surface of the heater for applying thermal energy to the ink in the recording head to discharge the ink from the recording head. An object of the present invention is to provide a method for reducing kogation adhesion to a heater of an ink and an ink jet recording head. Another object of the present invention is to provide an ink jet recording method and an ink jet recording apparatus that enable higher quality printing and further achieve a longer life of the recording head. It is in. Another object of the present invention is to provide a recording unit that can perform high-quality printing for a longer period of time. Another object of the present invention is to provide a method for extending the life of a recording head that can achieve excellent quality printing at a lower cost.

The above object can be achieved by the present invention described below. That is, the present invention is an ink for ink-jet recording used for ink-jet recording in which the ink is ejected by applying thermal energy to the ink, comprising: (a) a color material, (b) a liquid medium, (c) serine ( aliases: 2-amino-3-hydroxypropionic acid) and isoserine (aka: at least one acid and / or salt thereof is selected from 3-amino-2-hydroxypropionic acid), see containing a, (d) glycerin The content of (c) is 2 to 20% by mass with respect to the total amount of the ink . The ink of the present invention having such a configuration particularly includes a heater for applying thermal energy to the ink to discharge the ink from the orifice, a metal for protecting the heater, and / or an oxide of the metal. It is suitably used for an ink jet recording apparatus having a recording head provided with a surface protective layer.

  According to another aspect of the present invention, there is provided an inkjet recording method including a step of applying thermal energy to an ink by a heater and discharging the ink from an orifice provided in a recording head. An ink jet recording method characterized by being an ink.

  When an image is formed by using the ink of the present invention on the ink jet recording apparatus having the ink jet recording system having the above configuration, the outermost surface protection of the heater for applying thermal energy to the ink and discharging the ink from the orifice It is possible to extremely effectively reduce the adhesion of kogation to the outermost protective layer of the heater without dissolving the layer.

  Although the reason why such a kogation reduction effect is obtained by using the ink of the present invention is not clear, according to the study of the present inventors, the hydroxyl group and amino group in the structure of the component (c) are contained in the ink. It is presumed that the carboxyl group and the three hydroxyl groups in the glycerin structure as the component (d) interact to reduce kogation adhesion to the heater surface or to decompose kogation. It was confirmed that the life of the head could be extended by this kogation reducing action.

  Furthermore, when the metal and / or oxide thereof contained in the outermost surface protective layer of the heater is tantalum and / or an oxide of tantalum, the above-described kogation adhesion reducing effect and the outermost surface protective layer dissolution preventing effect Was found to be more prominent.

Further, E _{op is} the amount of energy input to the heater for applying thermal energy to the ink and discharging the ink from the orifice, and E _th is the minimum amount of energy input to the heater required to discharge the ink. It was also found that the above-described kogation prevention effect can be further improved by setting the amount of energy input to the heater so that the value of E _op / E _th satisfies the following relationship.
1.10 ≦ E _op / E _th ≦ 1.70

In addition, an ink jet recording apparatus which is another embodiment capable of achieving the above-described object of the present invention includes an ink storage portion storing ink, and ink in an ink flow path guided from the ink storage portion. An ink jet recording apparatus comprising an ink jet recording head having a heater for applying thermal energy, and means for applying a pulsed electric signal to the heater in accordance with recording information, wherein the heater is made of metal and / or An outermost surface protective layer containing the metal oxide is provided, and the ink is the ink of the present invention described above .

  In addition, a recording unit which is another embodiment capable of achieving the object of the present invention includes an ink storage portion that stores ink, and an ink jet for discharging the ink from an orifice by the action of thermal energy. A recording unit having a recording head portion, wherein the inkjet recording head includes a heater provided with an outermost protective layer containing a metal and / or an oxide of the metal for applying thermal energy to the heater. And the ink is the ink of the present invention described above.

Furthermore, the above-described method for extending the life of a recording head, which can achieve the object of the present invention, is used in an ink jet recording method including a step of applying thermal energy to ink and ejecting it from an orifice. A method of extending the life of a recording head comprising a heater for applying thermal energy to ink, wherein the heater is provided with an outermost surface protective layer containing a metal and / or an oxide of the metal, The ink of the present invention described above .

  U.S. Pat. No. 5,679,143 showed that bleed suppression and pH adjustment were achieved when the ink contained the following amino acids. As amino acids, β-alanine, 4-aminobutyric acid, DL-alanine, glycine, threonine, sarcosine, diiodo-L-tyrosine, L-glutamic acid, L-histidine, hydroxy-L-proline, DL-isoleucine, DL-leucine , L-lysine, DL-methionine, DL-phenylalanine, L-proline, DL-serine, L-tryptophan, L-tyrosine, 6-aminocaproic acid, and DL-valine. However, this prior art does not disclose any configuration of the present invention using glycerin, and of course, there is no description or suggestion regarding the remarkable effect of the present invention. Furthermore, as a result of studies by the present inventors, it has been found that at least amino acids such as β-alanine, DL-alanine, glycine, and L-glutamic acid cannot achieve the kogation reducing effect of the present invention.

  According to the present invention, in particular, in ink jet recording using thermal energy, kogation adhesion on the heater surface of the recording head can be effectively reduced, and further, the ink of the ink jet recording head can improve the life of the recording head. There are provided a method for reducing burnt adhesion to a heater, an ink jet recording method, an ink jet recording apparatus, an ink jet recording unit, and a method for extending the life of a recording head.

Next, the present invention will be described in more detail with reference to preferred embodiments.
First, the ink according to the present invention will be described. The ink contains (a) a coloring material, (b) a liquid medium, (c) an acid having a hydroxyl group (—OH) and an amino group (—NH ₂ ) and / or a salt thereof, and (d) glycerin as constituent components. . As a result of intensive investigations on a method for reducing burnt adhering to the heater of the inkjet recording head in an inkjet recording method in which ink is ejected as ink droplets by the action of thermal energy, the present inventor If (c) is used, the generation of kogation can be reduced, and if (d) is used in combination, the generation of kogation can be reduced very efficiently, and the life of the recording head can be extended. As a result, the present invention has been achieved. Hereinafter, each component of the ink of the present invention will be described.

<(C) component>
First, the component (c) characterizing the ink according to the present invention will be described.
The component (c) used in the present invention, serine (also known as 2-amino-3-hydroxypropionic acid _{.HO-CH 2 -CH (NH 2} ) -COOH), isoserine (aka: 3-Amino-2- hydroxypropionic acid _{.H 2 N-CH 2 -CH (} OH) -COOH) and the like.

  Since serine and isoserine have asymmetric carbon atoms, D-form, L-form and DL-form exist, and any of them can be used, but generally L-serine and DL-serine are easily available. it can.

  Component (c) may be used in acid form, but may be used in salt form. When a salt is used as the component (c), a commercially available compound in a salt form may be used as it is, or an alkali agent may be added to prepare a salt form of an organic acid. Good. Examples of the alkaline agent used in this case include lithium hydroxide, sodium hydroxide, potassium hydroxide, aqueous ammonia (ammonium hydroxide), organic amines (for example, triethanolamine, diethanolamine, monoethanolamine, diisopropanolamine, triisopropanol). Amine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, etc.). As the organic acid salt, an ammonium salt is preferably used among the above.

  When preparing the ink according to the present invention, the component (c) mentioned above can be used alone or in combination of two or more of the compounds listed above. May be. The total content of the component (c) is preferably used in the range of 0.005 to 20% by mass with respect to the total amount of ink, and further in the range of 0.05 to 12% by mass with respect to the total amount of ink. It is more preferable to contain. By setting it within this range, it is possible to obtain an ink having an excellent effect of reducing kogation and hardly causing nozzle clogging of the recording head.

<(D) Glycerin>
Next, glycerin that is the component (d) of the ink according to the present invention will be described. The total content of the component (d) is preferably used in the range of 0.1 to 25% by mass with respect to the total amount of ink, and further contained in the range of 2 to 15% by mass with respect to the total amount of ink. More preferably. By setting it within this range, it is possible to obtain an ink that has a more excellent kogation reduction effect and is less likely to cause nozzle clogging of the recording head.

  In the ink according to the present invention, the mass ratio of the content of the component (c) and the content of the component (d) described above in the ink is preferably 20: 1 to 1:20. When the mass ratio is in this range, the effect of reducing the adhesion of kogation to the heater is more exhibited, and ink that is less likely to cause nozzle clogging of the recording head can be obtained.

<(A) Color material>
Next, the color material that is the component (a) of the ink according to the present invention will be described. As the coloring material, it is preferable to use at least one of a dye and a pigment.

(dye)
As the dye, water-soluble dyes are preferable, and dyes such as direct dyes, acid dyes, basic dyes, and disperse dyes can be used.

Specifically, for example, the following can be used as appropriate. However, it is not limited to these.
C. I. Direct Black-4, Same-9, Same-11, Same-17, Same-19, Same-22, Same-32, Same-80, Same-151, Same-154, Same-168, Same-171, Same -194, -195,
C. I. Direct Blue-1, Same-2, Same-6, Same-8, Same-22, Same-34, Same-70, Same-71, Same-76, Same-78, Same-86, Same-142, Same -199, -200, -201, -202, -203, -207, -218, -236, -287,
C. I. Direct Red-1, Same-2, Same-4, Same-8, Same-9, Same-11, Same-13, Same-15, Same-20, Same-28, Same-31, Same-33, Same -37, -39, -51, -59, -62, -63, -73, -75, -80, -81, -83, -87, -90 -94, -95, -99, -101, -110, -189, -225, -227,
C. I. Direct Yellow-1, Same-2, Same-4, Same-8, Same-11, Same-12, Same-26, Same-27, Same-28, Same-33, Same-34, Same-41, Same -44, -48, -86, -87, -88, -132, -135, -142, -144,

C. I. Food Black-1, 2
C. I. Acid Black-1, Same-2, Same-7, Same-16, Same-24, Same-26, Same-28, Same-31, Same-48, Same-52, Same-63, Same-107, Same -112, -118, -119, -121, -172, -194, -208,
C. I. Acid Blue-1, Same-7, Same-9, Same-15, Same-22, Same-23, Same-27, Same-29, Same-40, Same-43, Same-55, Same-59, Same -62, -78, -80, -81, -90, -102, -104, -111, -185, -254,
C. I. Acid Red-1, Same-4, Same-8, Same-13, Same-14, Same-15, Same-18, Same-21, Same-26, Same-35, Same-37, Same-52, Same -249, -257, -289,
C. I. Acid Yellow-1, Same-3, Same-4, Same-7, Same-11, Same-12, Same-13, Same-14, Same-19, Same-23, Same-25, Same-34, Same -38, -41, -42, -44, -53, -55, -61, -71, -76, -79,

C. I. Reactive Blue-1, Same-2, Same-3, Same-4, Same-5, Same-7, Same-8, Same-9, Same-13, Same-14, Same-15, Same-17, Same-18, Same-19, Same-20, Same-21, Same-25, Same-26, Same-27, Same-28, Same-29, Same-31, Same-32, Same-33, Same- 34, -37, -38, -39, -40, -41, -43, -44, -46,
C. I. Reactive Red-1, Same-2, Same-3, Same-4, Same-5, Same-6, Same-7, Same-8, Same-11, Same-12, Same-13, Same-15, Same-16, Same-17, Same-19, Same-20, Same-21, Same-22, Same-23, Same-24, Same-28, Same-29, Same-31, Same-32, Same- 33, -34, -35, -36, -37, -38, -39, -40, -41, -42, -43, -45, -46, -49, -50, -58, -59, -63, -64, -180,
C. I. Reactive Yellow-1, Same-2, Same-3, Same-4, Same-6, Same-7, Same-11, Same-12, Same-13, Same-14, Same-15, Same-16, Same-17, Same-18, Same-22, Same-23, Same-24, Same-25, Same-26, Same-27, Same-37, Same-42,
C. I. Reactive Black-1, Same-3, Same-4, Same-5, Same-6, Same-8, Same-9, Same-10, Same-12, Same-13, Same-14, Same-18,
Projet Fast Cyan 2 (Avisia), Projet Fast Magenta 2 (Avisia), Projet Fast Yellow 2 (Avisia), Projet Fast Black 2 (Avisia) )etc.

(Pigment)
Any pigment such as an inorganic pigment or an organic pigment can be used as the pigment. Specifically, the following can be used. However, it is not limited to this. Moreover, you may use together the above-mentioned dye.

Carbon black,
C. I. Pigment Yellow-1, the same-2, the same-3, the same-12, the same-13, the same-14, the same-16, the same-17, the same-73, the same-74, the same-75, the same-83, the same -93, -95, -97, -98, -114, -128, -129, -151, -154, -195,
C. I. Pigment Red-5, -7, -12, -48 (Ca), -48 (Mn), -57 (Ca), -57: 1, -57 (Sr), -112 , -122, -123, -168, -184, -202,
C. I. Pigment blue-1, the same-2, the same-3, the same-15: 3, the same-15: 34, the same-16, the same-22, the same-60,
C. I. Wat Blue-4, -6, etc.

(Dispersant)
When the pigments listed above are used as the coloring material of the ink, it is preferable to use a dispersant in order to stably disperse the pigment in the ink. As the dispersant, a polymer dispersant, a surfactant-based dispersant, or the like can be used. Examples of the polymer dispersant include polyacrylate, styrene-acrylic acid copolymer salt, styrene-methacrylic acid copolymer salt, styrene-acrylic acid-acrylic acid ester copolymer salt, and styrene-maleic acid copolymer. Polymer salt, acrylic acid ester-maleic acid copolymer salt, styrene-methacrylsulfonic acid copolymer salt, vinyl naphthalene-maleic acid copolymer salt, β-naphthalene sulfonic acid formalin condensate salt, polyvinyl pyrrolidone, polyethylene glycol , And polyvinyl alcohol can be used. Among these, those having a weight average molecular weight of 1,000 to 30,000 and an acid value of 100 to 430 are particularly preferable. Examples of the surfactant dispersant include lauryl benzene sulfonate, lauryl sulfonate, lauryl benzene carboxylate, lauryl naphthalene sulfonate, aliphatic amine salt, and polyethylene oxide condensate. The amount of these dispersants used is preferably in the range of pigment mass: dispersant mass = 10: 5 to 10: 0.5.

(Self-dispersing carbon black)
In the ink according to the present invention, as a coloring material, for example, by introducing a water-soluble group on the surface of carbon black as described in JP-A-5-186704 and JP-A-8-3498. Carbon black that can be self-dispersed can also be used. If carbon black capable of such self-dispersion is used, it is not always necessary to use the dispersants listed above.

  The dyes and pigments listed above used as the coloring material of the ink may be used alone or in combination of two or more. Moreover, although the density | concentration of these dyes and pigments is not limited, Usually, it selects suitably from the range of 0.1-20 mass% with respect to the ink whole quantity.

<(B) Liquid medium>
Next, the liquid medium as the component (b) constituting the ink according to the present invention will be described. As the liquid medium, one containing water is preferably used, and in particular, a mixed medium of water and a water-soluble organic solvent is preferably used. It is desirable to use deionized water rather than general water containing various ions. The water content is preferably in the range of 35 to 96% by mass with respect to the total amount of water-based ink. A water-soluble organic solvent is used to adjust the viscosity of the ink to an appropriate viscosity that is preferable for use, and to slow down the drying speed of the ink, increase the solubility of the coloring material, and prevent clogging of the nozzles of the recording head. It is used for the purpose. The amount of the water-soluble organic solvent in the ink of the present invention is preferably in the range of 5 to 40% by mass with respect to the total amount of the water-based ink.

  Specific examples of the water-soluble organic solvent used in the above include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, alkyl alcohols having 1 to 5 carbon atoms such as n-pentanol; amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; Oxyethylene or oxypropylene such as ethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol Pyrene copolymers; alkylene glycols containing 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, trimethylene glycol, triethylene glycol, 1,2,6-hexanetriol; trimethylolethane, triethylene Methylolpropane; lower alkyl ethers such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether; triethylene glycol dimethyl (or ethyl) ether, tetraethylene glycol dimethyl (Or ethyl) lower dialkyl ethers of polyhydric alcohol such as ether; alkano such as monoethanolamine, diethanolamine, triethanolamine Triethanolamine like; sulfolane, N- methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone. The above water-soluble organic solvents can be used alone or as a mixture.

<Additives>
Further, the ink according to the present invention includes, in addition to the above-mentioned components, various conventionally known general additives such as a viscosity adjuster, a pH adjuster, an antifungal agent, an antiseptic, an oxidation agent, if necessary. An inhibitor, an antifoaming agent, a surfactant, a nozzle drying inhibitor such as urea, and the like can be appropriately added and used.

<Ink physical properties>
Further, the ink according to the present invention having the above composition is suitably used for ink jet recording. For this reason, the preferred range of physical properties of the ink of the present invention is that the pH around 25 ° C. is 3 to 12, more preferably 4 to 10, and the surface tension is preferably 10 to 60 mN / m, more preferably 15 to 50 mN. / M, the viscosity is preferably in the range of 1 to 30 mPa · s, more preferably 1 to 10 mPa · s.

<Inkjet recording method and recording apparatus>
A preferred method for performing recording using the ink according to the present invention is an ink jet recording method in which thermal energy corresponding to a recording signal is applied to the ink in the recording head chamber and droplets are generated by the energy. A recording apparatus in which the ink of the present invention is preferably used will be described below with reference to the drawings.

(Recording method)
First, FIG. 1 and FIG. 2 show an example of a head configuration which is a main part of an ink jet recording apparatus using thermal energy. FIG. 1 is a cross-sectional view of the head 13 along the ink flow path, and FIG. 2 is a cross-sectional view taken along line AB in FIG. The head 13 is obtained by bonding glass, ceramic, silicon, polysulfone, a plastic plate, or the like having a flow path (nozzle) 14 through which ink passes, and the heating element substrate 15. The heating element substrate 15 includes a protective layer 16-1 formed of silicon oxide, silicon nitride, silicon carbide or the like, a metal such as platinum or an oxide of metal such as an oxide of platinum, preferably tantalum or an oxide of tantalum. The outermost surface protective layer 16-2 formed of, etc., electrodes 17-1 and 17-2 formed of aluminum, gold, aluminum-copper alloy, etc., refractory materials such as hafnium boride, tantalum nitride, tantalum aluminum, etc. The heating resistor layer 18 is formed, the heat storage layer 19 is formed of silicon oxide, aluminum oxide, or the like, and the substrate 20 is formed of a material having good heat dissipation such as silicon, aluminum, or aluminum nitride.

  When a pulsed electric signal is applied to the electrodes 17-1 and 17-2 of the head 13, the region (heater) indicated by n of the heating element substrate 15 rapidly generates heat, and the ink in contact with the surface is heated. Bubbles are generated in the nozzle 21, and the meniscus 23 protrudes by the pressure, and the ink 21 is discharged through the nozzle 14 of the head, becomes an ink droplet 24 from the discharge orifice 22, and flies toward the recording material 25. FIG. 3 shows an external view of an example of a multi-head in which a large number of heads shown in FIG. 1 are arranged. This multi-head is made by adhering a glass plate 27 having multi-nozzles 26 and a heating head 28 similar to that described in FIG.

(Amount of energy applied to the heater)
Next, the r value will be described. The r value is a factor that represents the ratio of the energy actually input to the critical energy that can be discharged by the bubble jet head. That is, when the pulse width applied to the bubble jet head is P (the total width when a plurality of pulses are divided and applied), the applied voltage is V, and the heater resistance is R, the input energy E is: It is represented by the following formula (A).
E = P × V ² / R (A)
At this time, assuming that the minimum energy required for the bubble jet head to discharge at the minimum is E _th and the input energy when actually driving is E _op , the r value is given by the following formula (B). It is done.
r = E _op / E _th (B)

As a method for obtaining the r value from the driving conditions of the bubble jet head, the following two methods (1) and (2) are practically used.
(1) When the pulse width is fixed;
First, an appropriate voltage discharged from the bubble jet head is found and driven with a given pulse width. Next, the voltage is gradually lowered to find a voltage at which ejection stops. Let V _th be the minimum dischargeable voltage immediately before this voltage. If the voltage actually used for driving is V _op , the r value can be obtained by the following equation (C).
r = (V _op / V _th ) ² (C)

(2) When the voltage is fixed;
First, an appropriate pulse width discharged by the bubble jet head is found and driven with a given voltage. Next, the pulse width is gradually shortened to find a pulse width at which ejection stops. Let P _th be the minimum pulse width that can be discharged immediately before this pulse width. If the pulse width actually used in driving is P _op , the r value can be obtained by the following equation (D).
r = P _op / P _th (D)

Note that the voltage value here is a voltage actually applied to the heater unit to cause the bubble jet heater to generate heat. Since the voltage applied from the outside of the head may drop due to a contact, wiring resistance, or the like, it cannot be used for calculating the r value in a strict sense. However, when V _th and V _op are measured from the outside of the head, these voltage fluctuations are included in both values, so unless these voltage fluctuations are large, these values are used directly. Even if the value is calculated, there is little error, and thus the value obtained can be used as the r value for convenience.

  Also, when recording is performed with an actual printer, it is necessary to note that the voltage to one heater may fluctuate due to this influence because a plurality of heaters are driven. Furthermore, from the equations (A) and (B), the square of V and P seem to be inversely proportional at the same r value, but in reality, the electrical problem such as the pulse waveform not being rectangular, If the waveform is different, there are thermal problems such as different heat diffusion around the heater, and if the voltage is different, there is a problem specific to bubble jet such as the heat flux from the heater to ink changes and the foaming state changes. Power and P are not a simple relationship. Therefore, the methods described in the above (1) and (2) must be handled independently, and it is noted that conversion from one value to the other by calculation causes an error. Must. In the present invention, unless otherwise specified, the value obtained by the above method (1) is defined as the r value.

  In order to stably eject ink, it is general to drive under the condition that the r value obtained as described above is about 1.12 to 1.96. However, when the ink of the present invention is used and thermal energy is applied to the ink and ejected from the recording head, the r value is driven within a predetermined range, specifically, 1.10 to 1.70. This is preferable because kogation is prevented from adhering to the heater, and the life of the recording head can be further extended. When the r value is in the above range, the adhesion of kogation can be particularly effectively prevented, and the reason why the life of the recording head can be extended is not clear. However, the present inventor thinks as follows. That is, if the r value is driven within this range, the heater is not supplied with excessive energy and the heater surface temperature does not become excessively high, and the metal erosion due to the component (c) may occur excessively. This is thought to be because there is not.

  FIG. 4 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held and fixed by a blade holding member, and forms a cantilever. The blade 61 is disposed at a position adjacent to a recording area by the recording head 65, and in the case of the apparatus example shown in FIG. 4, is held in a form protruding in the moving path of the recording head 65.

  Reference numeral 62 denotes a cap on the projection port surface 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, contacts the ink ejection port surface, and performs capping. The structure to perform is provided. Further, reference numeral 63 denotes an ink absorber provided adjacent to the blade 61 and, like the blade 61, is held in a form protruding in the moving path of the recording head 65. The blade 61, the cap 62, and the ink absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the ink absorber 63 remove moisture, dust, and the like from the ejection port surface.

  Reference numeral 65 denotes a recording head that has discharge energy generating means and performs recording by discharging ink onto a recording material facing the discharge port surface on which the discharge ports are arranged. This is a carriage for moving the recording head 65. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 (not shown) driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording area and its adjacent area can be moved by the recording head 65.

  Reference numeral 51 denotes a paper feed unit for inserting a recording material, and 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection port surface of the recording head 65, and is discharged to a paper discharge portion provided with a paper discharge roller 53 as recording progresses. In the above configuration, when the recording head 65 finishes recording and returns to the home position, the cap 62 of the ejection recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. . As a result, the ejection port of the recording head 65 is wiped.

  When the cap 62 is in contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving 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 at the same position as that at the time of wiping described above. As a result, the ejection port surface of the recording head 65 is wiped even during this movement. The above-mentioned movement of the recording head to the home position is not only at the end of recording or at the time of ejection recovery, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves the recording area for recording. Then, the wiping is performed with this movement.

  FIG. 5 is a diagram illustrating an example of an ink cartridge 45 that contains ink supplied to the recording head via an ink supply member, for example, a tube. Reference numeral 40 denotes an ink container, for example, an ink bag, which stores ink for supply, and a rubber plug 42 is provided at the tip of the ink container. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the head. An ink absorber 44 receives waste ink. The ink container preferably has a liquid contact surface made of polyolefin, particularly polyethylene.

  The ink jet recording apparatus of the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, but may be one in which they are integrated as shown in FIG. In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage portion that stores ink, for example, an ink absorber is stored, and the ink in the ink absorber from the head portion 71 having a plurality of orifices. It is configured to be ejected as ink droplets. It is preferable for the present invention to use polyurethane as the material of the ink absorber. Alternatively, a structure may be used in which the ink container is an ink bag with a spring or the like inside without using an ink absorber. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 4 and is detachable from the carriage 66.

  EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited by the following Example, unless the summary is exceeded. In the text, “parts” and “%” are based on mass unless otherwise specified. Further, acetylenol EH (surfactant) used in Examples and Comparative Examples is an acetylene glycol ethylene oxide adduct.

<Examples 1-3 and Comparative Example 1>
First, the components shown below were mixed, sufficiently stirred and dissolved, and then filtered under pressure with a microfilter (manufactured by Fuji Photo Film Co., Ltd.) having a pore size of 0.2 μm. The ink of Comparative Example A from which L-serine was removed from the ink of Example A and the ink of Comparative Example B from which glycerin was removed from the ink of Example A were prepared.

(Ink composition of Example A)
・ Projet Fast Black 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 5 parts glycerin 5 parts L-serine 2 parts sodium hydroxide 0.2 parts water 85.8 parts

(Ink composition of Comparative Example A)
・ Projet Fast Black 2 [Abisia Co., Ltd.
Made] 2 parts · Diethylene glycol 5 parts · Glycerin 5 parts · Sodium hydroxide 0.2 parts · Water 87.8 parts

(Ink composition of Comparative Example B)
・ Projet Fast Black 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 5 parts L-serine 2 parts sodium hydroxide 0.2 parts water 90.8 parts

[Evaluation 1]
On-demand type multi-recording head [BC-02 (manufactured by Canon Inc.)]: on the heater, which ejects ink by applying thermal energy corresponding to the recording signal to the ink using the ink of Example A above. The outermost surface protective layer was made of tantalum and an oxide of tantalum] and evaluated by discharging ink under the following conditions. In the first embodiment, the ink discharge conditions of the ink jet recording apparatus are as follows. In Example 1, the pulse width is 1.1 μs (on) +3.0 μs (off) +3.2 μs (on), the drive frequency is 6,250 Hz, and V _th (the limit of discharge). Was measured, and ink was ejected by applying V _op (driving voltage) corresponding to r value = 1.39. Then, the ejection durability in the ink jet recording head and the adhesion of kogation to the heater when ink jet recording was performed under these conditions were evaluated by the following methods and criteria, respectively. The results are shown in Table 1. V _op (drive voltage) was calculated from the following equation.
V _op = √r × V _th

Further, using the ink of Example A, the same evaluation was performed with V _op (driving voltage) corresponding to r value = 1.39, Example 1 and V _op (corresponding to r value = 1.10). Example 2 was the same evaluation for the driving voltage), and Example 3 was the same evaluation for V _op (driving voltage) corresponding to r value = 1.65.

Further, the inks of Comparative Example A not containing L-serine and the ink of Comparative Example B not containing glycerin were evaluated in the same manner at V _op (driving voltage) corresponding to r value = 1.39. It was set as Comparative Example 1 and Comparative Example 2. The results are shown in Table 1.

[Discharge durability]
For Examples 1 to 3 and Comparative Examples 1 and 2, continuous discharge was performed under the above-described apparatus and driving conditions, and droplets discharged from the recording head every 1 × 10 ⁶ shots were collected in a container and weighed with an electronic balance did. The average discharge droplet amount at 1 × 10 ⁶ shots was calculated from the increase amount of the container. The continuous discharge was performed up to 1 × 10 ⁸ shots and evaluated according to the following criteria. The results are shown in Table 1. Here, it is determined that the evaluation B or higher can be practically used.
A: The average discharge droplet amount between 9.9 × 10 ⁷ to 1 × 10 ⁸ shots is 90% or more compared with the average discharge droplet amount after 0 to 1 × 10 ⁶ shots.
B: The average discharge droplet amount between 9.9 × 10 ⁷ to 1 × 10 ⁸ shots is less than 90% to 70% or more compared to the average discharge droplet amount after 0 to 1 × 10 ⁶ shots.
C: The average discharge droplet amount between 9.9 × 10 ^{7 and} 1 × 10 ⁸ shots is less than 70% compared with the average discharge droplet amount after 0 to 1 × 10 ⁶ shots.
D: Discharge was impossible on the way.

[Koge adhesion amount]
The recording head used in the above discharge durability evaluation of the head was disassembled after completion, and the heater surface of the nozzle used for discharge durability was observed with an optical microscope (400 times magnification). evaluated.
A: Almost no adhesion of kogation is observed.
B: Slight adhesion of koge is observed.
C: A lot of kogation is observed.
D: Very much adhesion of koge is seen.

<Examples 4 to 12 and Comparative Examples 3 to 11>
The components shown below were mixed and sufficiently stirred to dissolve, and then pressure filtered through a microfilter (manufactured by Fuji Photo Film Co., Ltd.) having a pore size of 0.2 μm to prepare inks of Examples 4-12. The main composition of the ink is shown in Table 2-1.

(Ink composition of Example 4)
・ Projet Fast Black 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 5 parts glycerin 5 parts DL-isoserine 2 parts sodium hydroxide 0.2 parts water 85.8 parts

(Ink composition of Example 5)
・ Projet Fast Yellow 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 5 parts glycerin 5 parts L-serine 2 parts water 86 parts

(Ink composition of Example 6)
・ Projet Fast Magenta 2 [Abisia Co., Ltd.
Made] 2 parts · Diethylene glycol 5 parts · Glycerin 5 parts · L-serine 3 parts · Water 85 parts

(Ink composition of Example 7)
・ Projet Fast Cyan 2 [Abisia Co., Ltd.
Made] 2 parts · Diethylene glycol 5 parts · Glycerin 5 parts · L-serine 3 parts · Water 85 parts

[Ink of Example 8]
(Preparation of pigment dispersion 1)
-Styrene-acrylic acid-butyl acrylate copolymer (acid value 116, average molecular weight 3,700) 5 parts-Triethanolamine 0.5 part-Diethylene glycol 5 parts-Water 69.5 parts

  The above components are mixed and heated to 70 ° C. in a water bath to completely dissolve the resin components. To this solution, 15 parts of carbon black “MA-100” (pH 3.5; manufactured by Mitsubishi Chemical Corporation) and 5 parts of 2-propanol were added, and after 30 minutes of premixing, dispersion treatment was performed under the following conditions. It was.

・ Disperser: Sand grinder (Igarashi Machine)
・ Crushing media: 1 mm diameter of zirconium beads ・ Filling rate of grinding media: 50% (volume)
-Grinding time: 3 hours Further, centrifugal treatment (12,000 rpm, 20 minutes) was carried out to remove coarse particles to obtain pigment dispersion 1. The solid content of the obtained pigment dispersion 1 was 15%.

(Preparation of ink of Example 8)
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours to obtain the ink of Example 8 used in the present invention.
・ Pigment dispersion 1 30 parts ・ Diethylene glycol 5 parts ・ Glycerin 5 parts ・ 2-propanol 2 parts ・ L-serine 2 parts ・ Water 56 parts

[Ink of Example 9]
(Preparation of pigment dispersion 2)
After mixing 300 g of commercially available acidic carbon black “MA77” (pH 3; manufactured by Mitsubishi Chemical Corporation) with 1,000 ml of water, 450 g of sodium hypochlorite (effective chlorine concentration 12%) was added dropwise thereto, The mixture was stirred at 100 to 105 ° C. for 10 hours. The obtained slurry was Toyo Filter Paper No. 2 (manufactured by Advantis) and sufficiently washed the pigment particles with water. This pigment wet cake was re-dispersed in 3,000 ml of water, and desalted with a reverse osmosis membrane to an electric conductivity of 0.2 μs. Further, this pigment dispersion (pH = 8 to 10) was concentrated to a pigment concentration of 10%. By the above method, -COONa group was introduced on the surface of carbon black.

(Preparation of ink of Example 9)
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours. This mixture was pressure-filtered with a membrane filter (manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 3.0 μm as the ink of Example 9 used in the present invention.
・ Pigment dispersion 2 30 parts ・ Glycerin 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (manufactured by Kawaken Fine Chemicals)
0.2 part L-serine 2 parts water 57.8 parts

[Ink of Example 10]
(Preparation of pigment dispersion 3)
・ Styrene-acrylic acid copolymer (acid value 200,
(Average molecular weight 7,000) 5.5 parts ・ Monoethanolamine 1.0 part ・ Ion-exchanged water 67.5 parts ・ Diethylene glycol 5.0 parts

  The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. In this solution, C.I. I. 20 parts of Pigment Yelloe 93 and 1.0 part of isopropyl alcohol were added and premixing was performed for 30 minutes, followed by dispersion treatment under the following conditions.

-Disperser: Sand grinder-Grinding media: Glass beads 1mm diameter-Filling rate of grinding media: 50% (volume)
-Grinding time: 3 hours Further, centrifugal treatment (12,000 rpm, 20 minutes) was carried out to remove coarse particles to obtain pigment dispersion 3. The solid content of the obtained pigment dispersion 3 was 20%.

(Preparation of ink of Example 10)
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours to obtain the ink of Example 10 used in the present invention.
・ Pigment dispersion 3 20 parts ・ Glycerin 15 parts ・ Diethylene glycol 10 parts ・ Acetyleneol EH (manufactured by Kawaken Fine Chemicals)
0.3 part L-serine 2 parts water 52.7 parts

[Ink of Example 11]
(Preparation of pigment dispersion 4)
・ Styrene-acrylic acid copolymer (acid value 200,
(Average molecular weight 7,000) 5.5 parts ・ Monoethanolamine 1.0 part ・ Ion-exchanged water 67.5 parts ・ Diethylene glycol 5.0 parts

  The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. In this solution, C.I. I. 20 parts of Pigment Red 122 and 1.0 part of isopropyl alcohol were added, and after 30 minutes of premixing, dispersion treatment was performed under the following conditions.

-Disperser: Sand grinder-Grinding media: Glass beads 1mm diameter-Filling rate of grinding media: 50% (volume)
-Grinding time: 3 hours Further, centrifugal treatment (12,000 rpm, 20 minutes) was carried out to remove coarse particles to obtain a pigment dispersion 4. The solid content of the obtained pigment dispersion 4 was 20%.

(Preparation of ink of Example 11)
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours to obtain the ink of Example 11 used in the present invention.
・ Pigment dispersion 4 20 parts ・ Glycerin 15 parts ・ Diethylene glycol 10 parts ・ Acetyleneol EH (manufactured by Kawaken Fine Chemicals)
0.3 part L-serine 2 parts water 52.7 parts

[Ink of Example 12]
(Preparation of pigment dispersion 5)
・ Styrene-acrylic acid copolymer (acid value 200,
(Average molecular weight 7,000) 5.5 parts ・ Monoethanolamine 1.0 part ・ Ion-exchanged water 67.5 parts ・ Diethylene glycol 5.0 parts

  The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. In this solution, C.I. I. 20 parts of Pigment Blue 15: 3 and 1.0 part of isopropyl alcohol were added and premixing was performed for 30 minutes, followed by dispersion treatment under the following conditions.

-Disperser: Sand grinder-Grinding media: Glass beads 1mm diameter-Filling rate of grinding media: 50% (volume)
-Grinding time: 3 hours Further, centrifugal treatment (12,000 rpm, 20 minutes) was carried out to remove coarse particles to obtain a pigment dispersion 5. The solid content of the obtained pigment dispersion 5 was 20%.

(Preparation of ink of Example 12)
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours to obtain the ink of Example 12 used in the present invention.
・ Pigment dispersion 5 20 parts ・ Glycerin 15 parts ・ Diethylene glycol 10 parts ・ Acetyleneol EH (manufactured by Kawaken Fine Chemicals)
0.3 part L-serine 2 parts water 52.7 parts

<Comparative Examples 3-11>
The components shown below were mixed, sufficiently stirred and dissolved, and then pressure-filtered with a micro filter (manufactured by Fuji Photo Film Co., Ltd.) having a pore size of 0.2 μm, so that the inks of Comparative Examples 3 to 11 were used. Prepared.

(Ink composition of Comparative Example 3)
・ Projet Fast Black 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 10 parts sodium hydroxide 0.2 parts water 87.8 parts

(Ink composition of Comparative Example 4)
・ Projet Fast Yellow 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 10 parts water 88 parts

(Ink composition of Comparative Example 5)
・ Projet Fast Magenta 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 10 parts water 88 parts

(Ink composition of Comparative Example 6)
・ Projet Fast Cyan 2 [Abisia Co., Ltd.
Made] 2 parts diethylene glycol 10 parts water 88 parts

(Preparation of ink of Comparative Example 7)
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours. The mixture was pressure-filtered with a membrane filter (manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 3.0 μm to obtain an ink of Comparative Example 7.
・ Pigment dispersion 1 30 parts ・ Diethylene glycol 10 parts ・ 2-propanol 2 parts ・ Water 58 parts

(Preparation of ink of Comparative Example 8)
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours. The mixture was pressure-filtered with a membrane filter (manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 3.0 μm as the ink of Comparative Example 8.
・ Pigment dispersion 2 30 parts ・ Glycerin 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (manufactured by Kawaken Fine Chemicals)
0.2 part water 59.8 parts

<Preparation of ink of Comparative Example 9>
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours. The mixture was pressure-filtered with a membrane filter (manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 3.0 μm as the ink of Comparative Example 9.
・ Pigment dispersion 3 20 parts ・ Glycerin 15 parts ・ Diethylene glycol 10 parts ・ Acetyleneol EH (manufactured by Kawaken Fine Chemicals)
0.3 part water 54.7 parts

<Preparation of ink of Comparative Example 10>
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours. The mixture was pressure-filtered with a membrane filter (manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 3.0 μm as the ink of Comparative Example 10.
・ Pigment dispersion 4 20 parts ・ Glycerin 15 parts ・ Diethylene glycol 10 parts ・ Acetyleneol EH (manufactured by Kawaken Fine Chemicals)
0.3 part water 54.7 parts

<Preparation of ink of Comparative Example 11>
The following components were mixed in a beaker and stirred at 25 ° C. for 3 hours. The mixture was pressure-filtered with a membrane filter (manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 3.0 μm as the ink of Comparative Example 11.
・ Pigment dispersion 5 20 parts ・ Glycerin 15 parts ・ Diethylene glycol 10 parts ・ Acetyleneol EH (manufactured by Kawaken Fine Chemicals)
0.3 part water 54.7 parts

[Evaluation 2]
An on-demand type multi-recording head (BC-02 (Canon)) that ejects ink by applying thermal energy corresponding to a recording signal to the ink using the inks of Examples 4 to 12 and Comparative Examples 3 to 11 described above. Co., Ltd.): Using an inkjet recording apparatus having an outermost protective layer on the heater made of tantalum and tantalum oxide), pulse width 1.1 μs (On) +3.0 μs (Off) +3.2 μs (On ) V _th (critical discharge voltage) was measured at a driving frequency of 6,250 Hz, and the following evaluation was performed at V _op (driving voltage) corresponding to r value = 1.39. The results are shown in Table 2-2.

[Discharge durability]
Continuous discharge was performed under the above-mentioned apparatus and driving conditions, and droplets discharged from the recording head every 1 × 10 ⁶ were collected in a container and weighed with an electronic balance. The average discharge droplet amount at 1 × 10 ⁶ shots was calculated from the increase amount of the container. In addition, continuous discharge was performed up to 1 × 10 ⁸ shots and evaluated according to the following criteria.
A: The average discharge droplet amount between 9.9 × 10 ⁷ to 1 × 10 ⁸ shots is 90% or more compared with the average discharge droplet amount after 0 to 1 × 10 ⁶ shots.
B: The average discharge droplet amount between 9.9 × 10 ⁷ to 1 × 10 ⁸ shots is less than 90% to 70% or more compared to the average discharge droplet amount after 0 to 1 × 10 ⁶ shots.
C: The average discharge droplet amount between 9.9 × 10 ^{7 and} 1 × 10 ⁸ shots is less than 70% compared with the average discharge droplet amount after 0 to 1 × 10 ⁶ shots.
D: Discharge was impossible on the way.

[Koge adhesion amount]
The recording head, which was evaluated for the ejection durability of the head, was disassembled, and the surface of the nozzle heater used for ejection durability was visually observed with an optical microscope (400 times magnification), and the amount of kogation was evaluated according to the following criteria. .
A: Almost no adhesion of kogation is observed.
B: Slight adhesion of koge is observed.
C: A lot of kogation is observed.
D: Very much adhesion of koge is seen.

It is a longitudinal cross-sectional view which shows an example of the recording head of the inkjet recording device of this invention. It is a cross-sectional view showing an example of a recording head of the ink jet recording apparatus of the present invention. FIG. 2 is an external perspective view of a head in which the recording head shown in FIG. It is a schematic perspective view which shows an example of the inkjet recording device of this invention. 2 is a perspective view of an internal configuration showing an example of an ink cartridge. FIG. It is a perspective view which shows an example of a recording unit.

Explanation of symbols

13: recording head 14: nozzle 15: heating element substrate 16-1: protective layer 16-2: outermost surface protective layer 17-1, 17-2: electrode 18: heating resistor layer 19: heat storage layer 20: substrate 21: Ink 22: discharge orifice (fine hole)
23: Meniscus 24: Ink droplet 25: Recording material 26: Multi-nozzle 27: Glass plate 28: Heat generating head 40: Ink bag 42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed unit 52: Paper feed Roller 53: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Discharge recovery unit 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head unit 72: Air Communication port

Claims (20)

An ink for ink jet recording used for ink jet recording in which the ink is ejected by applying thermal energy to the ink,
(A) Color material, (b) Liquid medium, (c) At least one selected from serine (alias: 2-amino-3-hydroxypropionic acid) and isoserine (alias: 3-amino-2-hydroxypropionic acid) seed acids and / or salts thereof, and, (d) glycerin seen including,
The ink according to claim 1, wherein the content of (c) is 2 to 20% by mass relative to the total amount of the ink. The ink according to claim 1, wherein the content of (d ) is 0.1 to 25% by mass with respect to the total amount of the ink. The ink according to claim 1 or 2 , wherein a mass ratio of (c ) to (d ) is from 20: 1 to 1:20. The ink according to any one of claims 1 to 3 , wherein (a ) is a water-soluble dye. Wherein (a) is ink according to any one of claim 1 to 4 which is a pigment. The ink according to any one of claims 1 to 5 , wherein (b ) contains water, and the content of the water is 35 to 96 mass% with respect to the total amount of the ink. The ink jet recording includes a heater for applying thermal energy to ink to discharge the ink from an orifice, and a metal for protecting the heater and / or an outermost protective layer containing an oxide of the metal. The ink according to any one of claims 1 to 6, which is performed by an ink jet recording apparatus having a head. The ink according to claim 7 , wherein the metal and / or the oxide of the metal is tantalum and / or an oxide of tantalum. A method for reducing kogation on a heater surface in an ink jet recording apparatus having a recording head provided with a heater for applying thermal energy to ink and discharging the ink from an orifice,
The heater surface comprising the outermost surface protective layer containing a metal and / or an oxide of the metal, and the ink is the ink according to any one of claims 1 to 6. A method for reducing kogation adhesion to the skin. The method for reducing kogation adhesion according to claim 9 , wherein the metal and / or the oxide of the metal is tantalum and / or an oxide of tantalum. When the energy input to the heater for discharging the ink is E _op and the energy to the heater necessary for discharging the ink from the recording head is E _th ,
The kog deposit reduction method according to claim 9 or 10 , wherein E _op / E _th satisfies the following relationship.
1.10 ≦ E _op / E _th ≦ 1.70 In an inkjet recording method including a step of applying thermal energy to ink by a heater and discharging the ink from an orifice provided in a recording head.
An ink jet recording method, wherein the ink is the ink according to any one of claims 1 to 6 . When the energy input to the heater for discharging the ink is E _op and the energy to the heater necessary for discharging the ink from the recording head is E _th ,
The inkjet recording method according to claim 12 , wherein E _op / E _th satisfies the following relationship.
1.10 ≦ E _op / E _th ≦ 1.70 Ink storage section for storing ink, inkjet recording head having a heater for applying thermal energy to ink in an ink flow path guided from the ink storage section, and means for applying a pulsed electrical signal to the heater An ink jet recording apparatus comprising:
The ink jet according to any one of claims 1 to 6, wherein the heater includes an outermost surface protective layer containing a metal and / or an oxide of the metal, and the ink is the ink according to any one of claims 1 to 6. Recording device. The inkjet recording apparatus according to claim 14 , wherein the metal and / or the oxide of the metal is tantalum and / or an oxide of tantalum. A recording unit having an ink containing portion containing ink and a head portion for discharging the ink from an orifice by the action of thermal energy,
The head portion includes a heater including a metal for applying thermal energy and / or an outermost protective layer containing an oxide of the metal, and the ink is any one of claims 1 to 6. A recording unit comprising the ink according to item 2 . The recording unit according to claim 16 , wherein the metal and / or the oxide of the metal is tantalum and / or an oxide of tantalum. A method for extending the life of a recording head comprising a heater for applying thermal energy to ink used in an ink jet recording method including a step of applying thermal energy to ink and discharging it from an orifice,
A recording head comprising: a heater and an outermost surface protective layer containing a metal and / or an oxide of the metal; and the ink according to any one of claims 1 to 6 being used as the ink. Long life method. 19. The method for extending the life of a recording head according to claim 18 , wherein the metal and / or the oxide of the metal is tantalum and / or an oxide of tantalum. When the energy input to the heater for discharging the ink is E _op and the energy to the heater necessary for discharging the ink from the recording head is E _th ,
E _op / E _th is, long life process of the recording head according to claim 18 or 19 satisfies the following.
1.10 ≦ E _op / E _th ≦ 1.70

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