JP2006117802A - Ink, ink cartridge and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new ink. <P>SOLUTION: The ink comprises a phthalocyanine-based organic pigment and the ink has a dispersant for adjusting disperse characteristics of the organic pigment and an additive for adjusting physical properties (e.g. surface tension) of the ink, and these dispersant and additive are the same polyoxyethylene-based anion surfactants. The polyoxyethylene-based surfactant includes e.g. a polyoxyethylenealkyl ether sulfate sodium salt, a polyoxyethylenealkyl ether sodium sulfate, a polyoxyethylenealkyl ether sodium acetate, a polyoxyethylenelauryl ether sodium acetate or a polyoxyethylenealkyl ether sulfate triethanol amine salt. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink containing an organic pigment, an ink cartridge, and an ink jet recording method.

  So-called inkjet recording, in which recording is performed by flying ink and adhering to the surface of a recording medium, has low noise during recording, is easily compatible with colorization, and can, for example, record and create high-resolution images at high speed. Therefore, it tends to be widely used as a recording method in printers and the like.

  Conventionally, ink in ink jet recording has been constituted by using various water-soluble dyes as a colorant and dissolving the water-soluble dye in water or a mixture of water and a water-soluble organic solvent. However, since water-soluble dyes have low light resistance, there is often a problem that an image recorded with a water-soluble dye or the like causes color spots due to discoloration or fading and deteriorates image quality.

  Further, even after the water-soluble dye is fixed on the surface of the recording medium in creating an image or the like, if water such as rain, sweat, food or drink adheres, the water-soluble dye is dissolved again in water. Accordingly, the water-soluble dye has low water resistance, and there are problems such as the recorded image blurring due to the adhesion of moisture and the recorded image disappearing.

  On the other hand, pigment inks using pigments as colorants are attracting attention as inks that have high water resistance and are unlikely to cause discoloration or fading due to light, but the dispersion stability of pigments in the ink is insufficient, For example, ejection stability has been regarded as a problem, for example, ink is solidified and clogged at the tip of a so-called orifice of a pen tip of a writing instrument or an ink ejection hole of a printer.

On the other hand, a pigment ink has been proposed for which the dispersion stability of the pigment has been studied (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3). In addition, proposals have been made on pigment inks for which suppression of ink solidification at the tip of the pen tip or orifice is studied (see, for example, Patent Document 4 and Patent Document 5) and recording liquids that have been studied mainly for inkjet recording. (For example, refer to Patent Document 6).
JP 61-235478 A JP-A-61-246271 JP 62-116678 A JP 56-41261 A JP 62-101672 A Japanese Patent Laid-Open No. 56-147859

  However, in the inkjet recording method, since it is necessary to discharge the pigment ink continuously and for a long time according to the size and resolution of the target recorded image, continuous discharge in a short time is required. Even in a possible pigment ink, when continuous ejection is performed for a long time, the ejection stability may be lowered.

  In particular, in an ink jet recording method using a method in which ink is ejected and flying by heating, the problem becomes serious because not only the ejection becomes unstable, but the ejection may not eventually be performed.

The present invention has been made in view of such a problem, and an object thereof is to provide a novel ink.
Another object of the present invention is to provide a novel ink cartridge that accommodates the ink.
Another object of the present invention is to provide a novel ink jet recording method using this ink.

  The ink according to the present invention is an ink containing an organic pigment, and includes a dispersant that adjusts the dispersion characteristics of the organic pigment and an additive that adjusts the physical characteristics of the ink, and the dispersant and the additive. Are the same surfactant.

  The ink according to the present invention has a dispersant for adjusting the dispersion characteristics of the organic pigment and an additive for adjusting the physical characteristics of the ink, and the dispersant and the additive are the same surfactant. Therefore, the dispersion state of the organic pigment is further stabilized.

  An ink cartridge according to the present invention is an ink cartridge that contains ink, wherein the ink includes an organic pigment, a dispersant that adjusts the dispersion characteristics of the organic pigment, and an additive that adjusts the physical characteristics of the ink. And the dispersant and the additive are the same surfactant.

  The ink cartridge according to the present invention includes a dispersant that adjusts the dispersion characteristics of the organic pigment constituting the ink to be contained, and an additive that adjusts the physical characteristics of the ink, and the dispersant and the additive are the same. Since the surfactant is used, an ink cartridge that contains ink in which the dispersion state of the organic pigment is further stabilized can be obtained.

  An ink jet recording method according to the present invention is an ink jet recording method in which ink is ejected by thermal energy and adhered to the surface of a recording medium, the ink comprising an organic pigment, and a dispersant for adjusting the dispersion characteristics of the organic pigment; And an additive for adjusting the physical properties of the ink, wherein the dispersant and the additive are the same surfactant.

  In the ink jet recording method according to the present invention, the ink jet recording method includes a dispersant for adjusting the dispersion characteristics of the organic pigment constituting the ink flying on the surface of the recording medium, and an additive for adjusting the physical characteristics of the ink. Since the same surfactant is used, an ink jet recording method using an ink in which the dispersion state of the organic pigment is further stabilized can be obtained.

  The present invention includes an organic pigment, a dispersant that adjusts the dispersion characteristics of the organic pigment, and an additive that adjusts the physical characteristics of the ink, and the dispersant and the additive are the same surfactant. Thus, a novel ink can be provided.

  Further, the present invention provides an ink cartridge for containing ink, wherein the ink includes an organic pigment, a dispersant that adjusts the dispersion characteristics of the organic pigment, and an additive that adjusts the physical characteristics of the ink. Thus, a novel ink cartridge can be provided with a configuration in which the dispersant and the additive are the same surfactant.

  The present invention also relates to an ink jet recording method in which ink is ejected by thermal energy to adhere to the surface of a recording medium. The ink includes an organic pigment, and the dispersant adjusts the dispersion characteristics of the organic pigment. Thus, a novel ink jet recording method can be provided by a constitution in which the dispersant and the additive are the same surfactant.

The best mode for carrying out the present invention will be described below with reference to the drawings. However, the present invention is not limited to this embodiment.
First, an embodiment of the ink according to the present invention will be described. In this embodiment, the ink according to the present invention contains an organic pigment, such as a phthalocyanine pigment or C.I. I. Pigment Blue PB15: 3 (unsubstituted copper phthalocyanine) (Chemical Formula 4), 15, 15: 1, 15: 4, 15: 6, 22, 60, 64, and includes at least one polyoxyethylene-based anion interface It has a dispersant and an additive by an activator. Note that the crystal form of the organic pigment is not limited to the β type, and may be, for example, the α type.

In this embodiment, the average particle size of the organic pigment is preferably in the range of 10 nm to 70 nm, and particularly preferably in the range of 10 nm to 40 nm, as the average particle size of the primary particles of the organic pigment measured using a transmission electron microscope. .
Further, the content of the organic pigment in the ink is preferably 0.1 to 15% by mass, particularly 1 to 10% by mass as compared with the ink.

  On the other hand, polyoxyethylene anionic surfactants include, for example, polyoxyethylene alkyl ether sulfate sodium salt, polyoxyethylene alkyl ether sulfate sodium salt, polyoxyethylene alkyl ether sodium acetate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl ether phosphate, Examples thereof include oxyethylene alkyl ether sulfate triethanolamine salt.

  In these polyoxyethylene anionic surfactants, the alkyl group preferably has 4 to 50 carbon atoms, more preferably 8 to 40 carbon atoms. When the number of carbon atoms is 4 or more, there is an effect of adsorbing to the pigment and dispersing the pigment, and when it is 8 or more, this effect becomes more remarkable. Further, when the carbon number is 50 or less, a water-soluble effect starts to appear, and when it is 40 or less, this effect becomes more remarkable.

  Further, the number of moles of oxyethylene added is preferably in the range of 1 to 40, and particularly preferably in the range of 2 to 30. When the oxyethylene addition mole number is 1 or more, the water solubility is effective, and when it is 2 or more, this effect becomes more remarkable. Moreover, when the oxyethylene addition mole number is 40 or less, there is an effect of dispersing the pigment, and when it is 30 or less, this effect becomes more remarkable.

In this embodiment, the total amount of the polyoxyethylene anionic surfactant constituting the ink according to the present invention added as a dispersant and an additive is 1.0% or more and 4.0% or less in the ink at the maximum. Preferably, the mass range is 1.0% or more and 3.0% or less.
This is because if the ink is smaller than 1.0%, the ink is likely to dry, for example, at the tip of the cartridge, that is, the nozzle surface of the orifice, and conversely if it is larger than 4.0%, This is because it becomes difficult to dry after adhering to the surface of a recording medium such as photographic paper.

The ink production method according to the present invention will be described. Prepare an aqueous medium with a predetermined amount of a dispersant based on a polyoxyethylene anionic surfactant, add a predetermined amount of a phthalocyanine pigment to the aqueous medium, stir, then disperse using a disperser, centrifuge, etc. A dispersion is prepared by removing coarse particles. Then, the ink by this invention can be produced by adding the additive by a polyoxyethylene surfactant, a predetermined aqueous medium, and salt, stirring and mixing and filtering. The salt is not particularly limited, and examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide. it can.

Examples of the aqueous medium include water or a mixed solvent of water and a water-soluble organic solvent.
As the water-soluble organic solvent, those having an action of preventing ink drying are preferable. For example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert- C1-C4 alkyl alcohols such as butyl alcohol; Amides such as dimethylformamide and dimethylacetamide; Ketones or ketoalcohols such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane Polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,5 Polyols having an alkylene group containing 2 to 6 carbon atoms, such as pentanediol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol; lower alkyl ether acetates such as polyethylene glycol monomethyl ether acetate; Glycerin; lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether; multivalents such as trimethylolpropane and trimethylolethane Alcohol; N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.

Further, any commercially available dispersing machine can be used, for example, a colloid mill, a flow jet mill, a slasher mill, a high speed disperser, a ball mill, an attritor, a sand mill, a sand grinder, an ultra fine mill. , Eiger motor mill, dyno mill, pearl mill, agitator mill, cobol mill, three rolls, two rolls, extruder, kneader, optimizer, microfluidizer, laboratory homogenizer, ultrasonic homogenizer and the like.
In the production of the ink according to the present invention, these dispersers may be used alone or in combination. Further, after mixing predetermined water or a water-soluble organic solvent, a predetermined amount of a dispersant may be added, and a predetermined amount of an organic pigment may be added, and then dispersed using a disperser.

  In the ink according to the present invention, the dispersant for adjusting the dispersion characteristics of the organic pigment in the solvent and the additive for adjusting the physical characteristics of the ink, for example, the surface tension, are constituted by the same surfactant. The ink can be prepared by adding a necessary amount of a surfactant as a dispersant in advance to the solvent before adding the organic pigment to the solvent and dispersing, or after the dispersion and centrifugation, that is, It can also be carried out by adding a necessary amount of a surfactant as an additive only at the stage of finally making an ink by adjusting physical properties such as surface tension.

  Further, when the ink according to the present invention is applied to a printer or the like by an ink jet recording method, it is important to discharge from, for example, an orifice of a recording head constituting the printer. In particular, viscosity and surface tension are important. The viscosity is preferably in the range of 1 to 15 cPs, particularly preferably in the range of 1 to 5 cPs, and the surface tension is preferably in the range of 25 to 60 dyn / cm, and particularly preferably in the range of 25 to 50 dyn / cm.

For this reason, when a mixed solvent of water and a water-soluble organic solvent is used as the aqueous medium constituting the ink according to the present invention, the water-soluble organic solvent includes glycerin, trimethylolpropane, thiodiglycol, ethylene glycol, 1, It is preferable to use 5-pentanediol, diethylene glycol, isopropyl alcohol, or acetylene alcohol.
In addition, the ink according to the present invention may contain a surfactant other than the surfactant constituting the dispersant and additives, an antifoaming agent, an antiseptic, an antifungal agent, a pH adjuster, an antioxidant, if necessary. For example, a commercially available water-soluble dye may be added for the purpose of toning and the like.

  Next, the best mode for carrying out the invention relating to the ink cartridge will be described.

  FIG. 1 shows an ink jet printer apparatus (hereinafter referred to as a printer apparatus) 1 using an ink cartridge of the present invention. The printer device 1 is a line-type printer device capable of so-called high-speed ejection that ejects ink or the like onto a recording paper P that travels in a predetermined direction to print an image or characters.

  The printer apparatus 1 is equipped with an ink jet printer head cartridge (hereinafter referred to as a head cartridge) 3. The head cartridge 3 has a cartridge main body 21 to which an ink cartridge 5 (described later) is mounted. The head cartridge 3 is mounted from the upper surface side of the printer body 4, that is, from the direction of arrow A in FIG.

  The head cartridge 3 is provided with ejection means for ejecting ink with fine particles and spraying the ink in a droplet state onto the main surface of an object such as the recording paper P to record images, characters, and the like. In the head cartridge 3, ink ejection ports (nozzles) are arranged in a substantially straight line in the width direction of the recording paper P, that is, in the direction of the arrow W in FIG. Discharged.

  As shown in FIG. 2, ink cartridges 5 y, 5 m, 5 c, and 5 k that are ink cartridges serving as ink supply sources and containing ink 2 are detachably attached to the head cartridge 3. That is, the yellow ink cartridge 5y, the magenta ink cartridge 5m, the cyan ink cartridge 5c, and the black ink cartridge 5k. The ink cartridge of the present invention is a cyan ink cartridge 5c.

  The ink cartridge 5 has a cartridge container 11 as shown in FIG. The cartridge container 11 includes an ink storage unit 12 that stores the ink 2, an ink supply unit 13 that supplies the ink 2 from the ink storage unit 12 to the cartridge body 21 of the head cartridge 3, and air from the outside into the ink storage unit 12. The external communication hole 14 for taking in the ink, the air introduction path 15 for introducing the air taken in from the external communication hole 14 into the ink containing portion 12, and the ink 2 between the external communication hole 14 and the air introduction path 15 temporarily. And a storage section 16 for storing in the storage.

  As described above, the ink cartridge is not limited to one that separates each ink separately. In addition, all kinds of commonly used ink cartridges such as one in which a plurality of ink storage portions are integrated can be employed.

  Next, the best mode for carrying out the invention relating to the ink jet recording method will be described.

  FIG. 4 schematically shows the head cartridge 3 used in the ink jet recording method of the present invention. The ink 2 stored in the ink cartridge 5 is supplied to the connection unit 26 through the ink supply unit 13. The ink 2 is supplied to the ink flow path 52 of the ink ejection head 27 through the ink reservoir 31, the filter 33, the valve mechanism 34, and the ink supply port 51 that constitute the connection portion 26. Further, the ink 2 is supplied from the ink flow path 52 to the nozzle 55a.

  A head chip 53 is disposed in the ink ejection head 27, and the nozzles 55a are arranged on the head chip 53 so as to form a substantially straight line in the width direction of the recording paper P, that is, the arrow W direction in FIG. Has been.

  As shown in FIG. 5A, the head chip 53 includes a substrate 54 serving as a base, a nozzle sheet 55 formed with a plurality of nozzles 55a, and a film 56 that partitions the substrate 54 and the nozzle sheet 55 for each nozzle 55a. And an ink liquid chamber 57 that pressurizes the ink 2 supplied through the ink flow path 52, and a heating resistor 58 that heats the ink 2 supplied to the ink liquid chamber 57, and drops ink droplets from the nozzle 55a. Discharging means for discharging.

  The heating resistor 58 is disposed on the substrate 54 facing the ink liquid chamber 57 and is electrically connected to the control circuit of the substrate 54. The nozzle 55 a is a minute hole opened in a circular shape in the nozzle sheet 55, and is disposed so as to face the heating resistor 58.

  In the head chip 53, the control circuit of the substrate 54 controls the heating resistor 58 and supplies a pulse current to the heating resistor 58. Thereby, the heating resistor 58 is rapidly heated. As a result, the ink 2 in contact with the surface of the heating resistor 58 is rapidly heated, and the temperature of the ink 2 rises above the normal boiling point and reaches a spontaneous nucleation temperature of about 330 ° C. Since the heating by the heating resistor 58 is performed for a short time, the temperature gradient in the ink chamber 57 becomes extremely steep, and the ink 2 on the surface of the heating resistor 58 is brought into a boiling state all at once, so-called film boiling. It becomes a state. Thereafter, active boiling continues inside the bubbles generated by boiling, and ink bubbles b grow as shown in FIG. 5B.

  Then, as shown in FIG. 5C, the ink 2 in the ink liquid chamber 57 jumps out of the nozzle 55a with the momentum of the growth of the ink bubble b, and the ink bubble b is deprived of a large amount of heat of vaporization due to its expansion. Bubbles that drop in pressure rapidly contract. The ink 2 ejected from the nozzle 55a has its tail extended outside the nozzle 55a due to its inertia and the contraction of the ink bubbles b, and the ink droplet i is ejected from the nozzle 55a.

  Then, the same amount of ink 2 as the amount discharged from the nozzle 55 a by the capillary force of the nozzle 55 a trying to return to the original meniscus (the liquid level of the nozzle 55 a) is supplied to the ink liquid chamber 57 from the ink flow path 52. On the other hand, the ink bubbles b are further contracted by the inflow of the fresh ink 2 and eventually disappear.

  The head chip 53 described above employs an electrothermal conversion method in which the ink 2 is discharged while being heated by the heating resistor 58. However, the present invention is not limited to such a method. An electromechanical conversion method in which droplets of ink 2 are ejected electromechanically by an element may be employed.

  Next, examples according to the present invention will be described, but the present invention is not limited to these examples. In this example, “%” is mass%.

  First, the following dispersion was prepared.

(Dispersion 1)
The following components were mixed, dispersed with a paint shaker (media: zirconia 1 mm diameter, media filling ratio 70%), and coarse particles were removed with a centrifuge to obtain a dispersion.
C. I. Pigment Blue 15: 3 (Chemical 5) 15%
Dispersant Polyoxyethylene alkyl ether sulfate sodium salt (Persoft EF, Nippon Oil & Fats) 3.0%
82% pure water

  Thereafter, the dispersant was changed in the same manner, and the dispersion liquid was prepared.

(Dispersion 2)
Dispersant Polyoxyethylene alkyl ether sulfate sodium salt (Sinoline SPE-1200, manufactured by Shin Nippon Rika; POE (2) sodium lauryl ether sulfate) 3.0%
(Dispersion 3)
Dispersant Sodium polyoxyethylene alkyl ether acetate (9NS50, Shin Nippon Chemical Co., Ltd.) 3.0%
(Dispersion 4)
Dispersant Sodium polyoxyethylene lauryl ether acetate (2P45-S made by Shin Nippon Chemical Co., Ltd.) 3.0%
(Dispersion 5)
Dispersant Polyoxyethylene alkyl ether sulfate triethanolamine salt (Persoft EFT, manufactured by NOF Corporation) 3.0%
(Dispersion 6)
Dispersant Polyoxyethylene alkyl ether sulfate sodium salt (Persoft EDO, manufactured by NOF Corporation) 3.0%

Next, the ink composition used in this example is shown.
After mixing and stirring the following components, the ink was converted to an ink of the present invention by removing the mainstream portion again with a centrifuge.
<Ink composition>
Dispersions 1-6 13%
1,5-pentanediol 15%
Additive optional * 1
Ion-exchanged water (100 (%)-(dispersion (%) + (1,5-pentanediol) (%) + dispersant (%)))

  As the additive of * 1, the same surfactant as the dispersant contained in the dispersion was added in the amount as shown in Table 1 at the time of ink formation.

The following tests were conducted on these inks.
For ejection stability, an on-demand type ejection orifice with a diameter of 16 μm was used, in which all the ink was put in a cartridge and thermal energy was applied to the ink in the recording head to generate liquid droplets. The continuous discharge characteristics were tested at a driving frequency of 10 kHz and a driving voltage of 11V.

In this case, the quality of each characteristic was judged by observing and measuring the droplet discharge speed. The ejection speed was calculated by manipulating the delay of the driving signal of the driver to move the ink droplet image on the monitor and calculating the ejection speed from the movement distance and the delay time required for the movement distance.
In the continuous discharge test, the initial discharge speed and the discharge speed after 50 minutes are 10m / s or more at the beginning and 10m / s or more after 50 minutes (○), and 8m / s or more after 50 minutes after the initial test. 8 m / s or more (Δ), initial less than 8 m / s (×), and ◯ and Δ were good.

  As can be seen from Table 1, with respect to the combination of the dispersions 1 to 6 and the total amount of the surfactant added as a dispersant or additive, the result is ◯ or Δ in the following combinations, and good test results was gotten.

  That is, the dispersant and the additive are polyoxyethylene alkyl ether sulfate sodium salt (Persoft EF manufactured by Nippon Oil & Fats), and the total amount of these dispersant and additive is 1.0% or more compared to the ink. This is a case where the mass is 4.0% or less.

  Further, the dispersant and the additive are polyoxyethylene alkyl ether sulfate sodium salt (Sinoline SPE-1200, manufactured by Shin Nippon Rika Co., Ltd.), and the total amount of these dispersant and additive is 1.0% compared to the ink. This is the case where the mass is 4.0% or less.

  Further, the dispersant and the additive are polyoxyethylene alkyl ether sodium acetate (9NS50 manufactured by Shin Nippon Chemical Co., Ltd.), and the total amount of the dispersant and the additive is 1.0% or more and 3.0% compared to the ink. It is a case where it is set as the following mass.

  Further, the dispersant and the additive are sodium polyoxyethylene lauryl ether acetate (2P45-S manufactured by Shin Nippon Chemical Co., Ltd.), and the total amount of the dispersant and the additive is 1.0% or more as compared with the ink. This is a case where the mass is 0% or less.

  Further, the dispersant and the additive are polyoxyethylene alkyl ether sulfate triethanolamine salt (Persoft EFT manufactured by Nippon Oil & Fats), and the total amount of the dispersant and the additive is 1.0% compared to the ink. This is the case where the mass is 3.0% or less.

  Further, the dispersant and the additive are polyoxyethylene alkyl ether sulfate sodium salt (Persoft EDO, manufactured by Nippon Oil & Fats), and the total amount of the dispersant and the additive is 1.0% or more as compared with the ink 3 This is a case where the mass is 0% or less.

  From the above, according to the present embodiment, it is possible to provide an ink that can always be stably ejected even if ejected for a long time, an ink cartridge that contains this ink, and an ink jet recording method that uses this ink. it can.

  As described in the above embodiments, according to the present invention, it is possible to provide an ink that can maintain ejection stability even when continuous ejection is performed for a long time. Therefore, for example, when used as ink constituting a printer, the ink ejection performance of the printer can be improved.

FIG. 2 is a schematic perspective view illustrating an example of an ink cartridge that stores ink according to the present invention and a configuration of a printer including the ink cartridge. It is a schematic perspective view which shows an example of the ink cartridge which accommodates the ink by this invention. It is a schematic sectional drawing which shows the structure of an example of the ink cartridge by this invention. FIG. 2 is a schematic diagram for explaining an ink jet recording method according to the present invention. 5A to 5C are schematic views illustrating the principle of an example of the ink jet recording method according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Ink, 3 ... Head cartridge, 4 ... Printer main body, 5 ... Ink cartridge, 5y, 5m, 5c, 5k ... Ink cartridge, 11 ... Cartridge container, 12 ... ink container, 13 ... ink supply unit, 14 ... external communication hole, 15 ... air introduction path, 16 ... storage part, 21 ... cartridge body, 26 ... Connection part, 27 ... Ink discharge head, 31 ... Ink reservoir, 33 ... Filter, 34 ... Valve mechanism, 51 ... Ink supply port, 52 ... Ink flow path 53 ... Head chip, 54 ... Substrate, 55a ... Nozzle, 56 ... Film, 57 ... Ink liquid chamber, 58 ... Heating resistor

Claims (19)

An ink containing an organic pigment,
A dispersant for adjusting the dispersion characteristics of the organic pigment, and an additive for adjusting the physical characteristics of the ink,
An ink characterized in that the dispersant and the additive are the same surfactant.   The ink according to claim 1, wherein the organic pigment is a phthalocyanine pigment, and the surfactant is a polyoxyethylene anionic surfactant. The ink according to claim 1, wherein the organic pigment is unsubstituted copper phthalocyanine (Chemical Formula 1).

  The ink according to claim 1, wherein the dispersant and the additive are polyoxyethylene alkyl ether sulfate sodium salt.   The ink according to claim 4, wherein the total amount of the dispersant and the additive is 1.0% or more and 3.0% or less as compared to the ink.   2. The ink according to claim 1, wherein the dispersant and the additive are polyoxyethylene alkyl ether sulfate sodium salts.   The ink according to claim 6, wherein the total amount of the dispersant and the additive is 1.0% or more and 4.0% or less compared to the ink.   The ink according to claim 1, wherein the dispersant and the additive are sodium polyoxyethylene alkyl ether acetates.   The ink according to claim 8, wherein the total amount of the dispersant and the additive is 1.0% or more and 3.0% or less as compared to the ink.   The ink according to claim 1, wherein the dispersant and the additive are sodium polyoxyethylene lauryl ether acetate.   11. The ink according to claim 10, wherein the total amount of the dispersant and the additive is 1.0% or more and 3.0% or less as compared to the ink.   The ink according to claim 1, wherein the dispersant and the additive are polyoxyethylene alkyl ether sulfate triethanolamine salts.   13. The ink according to claim 12, wherein the total amount of the dispersant and the additive is 1.0% or more and 3.0% or less as compared to the ink. An ink cartridge for containing ink,
The ink has an organic pigment, a dispersant for adjusting the dispersion characteristics of the organic pigment, and an additive for adjusting the physical characteristics of the ink,
An ink cartridge, wherein the dispersant and the additive are the same surfactant.   The ink cartridge according to claim 14, wherein the organic pigment is a phthalocyanine pigment, and the surfactant is a polyoxyethylene anionic surfactant. 15. The ink cartridge according to claim 14, wherein the organic pigment is unsubstituted copper phthalocyanine (Chemical Formula 2).

An ink jet recording method for causing ink to fly by thermal energy and adhere to the surface of a recording medium,
The ink has an organic pigment, a dispersant for adjusting the dispersion characteristics of the organic pigment, and an additive for adjusting the physical characteristics of the ink,
An inkjet recording method, wherein the dispersant and the additive are the same surfactant.   18. The ink jet recording method according to claim 17, wherein the organic pigment is a phthalocyanine pigment, and the surfactant is a polyoxyethylene anionic surfactant. 18. The ink jet recording method according to claim 17, wherein the organic pigment is unsubstituted copper phthalocyanine (Chemical Formula 3).

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