JP2010046949A - Liquid composition for thermal inkjet recording, color ink, ink set, ink cartridge, and thermal inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid composition for thermal inkjet recording, which suppresses occurrence of bleeding generated in formation of a color image and is excellent in discharge even when being discharged by a thermal inkjet recording method. <P>SOLUTION: The liquid composition for thermal inkjet recording which includes water, a polyvalent metal salt and a liquid medium, includes a compound expressed by general formula (1) (wherein R<SB>1</SB>and R<SB>2</SB>are an alkyl group). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid composition for thermal ink jet recording and a color ink for thermal ink jet recording. The present invention also relates to a thermal ink jet recording ink set, a thermal ink jet recording ink cartridge, and a thermal ink jet recording apparatus using these.

  The ink jet recording method is easy for downsizing the apparatus, low running cost, colorization, and the like, and is advantageous for forming a color image. However, there are some problems while higher quality of the image is required. For example, when two different types of ink are applied to a recording medium adjacent to each other, the inks may be mixed at the boundary portion, and a phenomenon (bleeding) in which the quality of the color image is deteriorated may occur. . In particular, bleeding at the boundary between black ink and color ink has a great influence on image quality degradation, and various solutions have been studied.

For example, the occurrence of bleeding is caused by including a precipitating agent in one liquid composition in contact with the recording medium and a coloring material (coloring material) capable of generating a precipitate by the precipitating agent in the other liquid composition. The technique which suppresses is disclosed (refer patent document 1 and patent document 2). In this technique, a polyvalent metal salt is disclosed as a precipitating agent, and a dye having at least one carboxyl group is disclosed as a colorant capable of generating a precipitate with the polyvalent metal salt. Also disclosed is the case where the first liquid composition contains a colorant, that is, the case where both of the liquid compositions in contact are inks.
JP-A-5-202328 JP-A-6-106841

  However, according to the study by the present inventors, the bleeding suppression methods of Patent Documents 1 and 2 are as follows when a liquid composition containing a polyvalent metal salt is repeatedly ejected from a recording head by a thermal ink jet recording method. I found out that there might be problems.

  An outermost protective layer made of metal and / or metal oxide, such as tantalum or tantalum oxide, is provided on a heater (heat generating element substrate) that imparts thermal energy to the recording head. Dissolution of the outermost surface protective layer causes a heater disconnection, which deteriorates discharge and affects the quality of the formed image.

  Such discharge deterioration is considered to occur for the following reasons. That is, when the ink or liquid composition containing the polyvalent metal salt is overheated by the heater, the anion ions constituting the polyvalent metal salt are decomposed. Metal ion) concentration increases and alkalinity increases. Thereby, the outermost surface protective film made of a metal such as tantalum and / or a metal oxide provided on the heater is dissolved, the heater is disconnected, and the discharge is deteriorated.

  Accordingly, an object of the present invention is to suppress the occurrence of bleeding when a color image is formed, and to be ejected satisfactorily even when ejected by a thermal ink jet recording method, and a color ink for thermal ink jet recording. Is to provide.

  Another object of the present invention is to provide a thermal ink jet recording ink set, a thermal ink jet recording ink cartridge, and a thermal ink jet recording apparatus using these.

  Therefore, the present inventors have conducted intensive studies on liquid compositions and color inks that suppress the occurrence of bleeding when a color image is formed and that are well ejected even when ejected by a thermal ink jet recording method. As a result, the present invention has been achieved.

  The object is achieved by the present invention described below.

A thermal ink jet recording liquid composition according to an embodiment of the present invention is a thermal ink jet recording liquid composition containing water, a polyvalent metal salt, and a liquid medium, represented by the following general formula (1): It contains the compound represented, It is characterized by the above-mentioned.
General formula (1)

(In the formula, R ₁ and R ₂ represent an alkyl group.)

  An ink set for thermal ink jet recording according to an embodiment of the present invention is characterized in that the liquid composition and a colored ink that reacts with the liquid composition by contact with the liquid composition are combined. It is.

  An ink cartridge for thermal ink jet recording according to an embodiment of the present invention stores a liquid composition storage unit that stores the liquid composition, and a colored ink that reacts with the liquid composition by contact with the liquid composition. And a colored ink container.

  A thermal ink jet recording apparatus according to an embodiment of the present invention includes a liquid composition container that stores the liquid composition, and a recording head for discharging the liquid composition by a thermal ink jet recording method. It is a feature.

  A color ink for thermal ink jet recording according to an embodiment of the present invention includes a polyvalent metal salt, a compound represented by the general formula (1), a liquid medium, and a color material. Is.

  An ink set for thermal ink jet recording according to another embodiment of the present invention is characterized in that the color ink is combined with a black ink that reacts with the color ink by contact with the color ink. .

  An ink cartridge for thermal ink jet recording according to another embodiment of the present invention comprises a color ink containing portion that contains the color ink, and a black ink containing portion that contains the black ink. is there.

  A thermal ink jet recording apparatus according to another embodiment of the present invention includes a color ink containing portion for containing the color ink for thermal ink jet recording, and a recording head for discharging the color ink by a thermal ink jet recording method. It is characterized by this.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of bleeding can be suppressed and the liquid composition for thermal inkjet recording and the color ink for thermal inkjet recording which can discharge favorably even when it discharges with the thermal inkjet recording method can be provided. In addition, a thermal ink jet recording ink set, an ink jet recording ink cartridge, and a thermal ink jet recording apparatus that can achieve the above-described effects can be provided.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

[First Embodiment]
One specific embodiment of the present invention is referred to as a “first embodiment” and will be described below.

The first embodiment uses a liquid composition containing a polyvalent metal salt, a compound represented by the following general formula (1), and a liquid medium, and the liquid composition and the colored ink Are provided on the recording medium so that they form a contact state. In such an embodiment, the application of the liquid composition and the colored ink is performed by a thermal ink jet recording method.
General formula (1)

(In the formula, R ₁ and R ₂ represent an alkyl group.)

  The liquid composition used in the first embodiment will be described.

  Examples of the polyvalent metal salt contained in the liquid composition include polyvalent metal salts such as nitric acid, sulfuric acid, and acetic acid. Specific examples include magnesium nitrate, calcium nitrate, magnesium sulfate, calcium sulfate, magnesium acetate, and calcium acetate. Among them, it is preferable to use a polyvalent metal salt of nitric acid or a polyvalent metal salt of acetic acid. Specifically, for example, magnesium nitrate, calcium nitrate, magnesium acetate, and calcium acetate are preferably used. The liquid composition contains at least one selected from the polyvalent metal salts. The total content of the polyvalent metal salt contained in the liquid composition is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more with respect to the total amount of the liquid composition. Moreover, it is preferable that it is 20 mass% or less with respect to the liquid composition whole quantity, and it is more preferable that it is 12 mass% or less. By satisfying this condition, the occurrence of bleeding can be suppressed more favorably.

  As the compound represented by the general formula (1) contained in the liquid composition, acetamide, propionic acid amide, butyramide, N-methylacetamide, and N-ethylacetamide are preferable. The liquid composition contains at least one selected from the compounds represented by the general formula (1). The total content of the compound represented by the general formula (1) contained in the liquid composition is preferably 1% by mass or more, more preferably 1.75% by mass or more with respect to the total amount of the liquid composition. preferable. Moreover, it is preferable that it is 20 mass% or less with respect to the liquid composition whole quantity, and it is more preferable that it is 7 mass% or less. By satisfying this condition, it is possible to extend the life of a more excellent head and to discharge the liquid composition satisfactorily.

  As the liquid medium contained in the liquid composition, it is preferable to use water and a water-soluble organic solvent in combination. In this case, it is desirable to use deionized water instead of general water containing various ions. The water content is preferably 35% by mass or more based on the total amount of ink. Moreover, 96 mass% or less is preferable. A water-soluble organic solvent is used for various purposes such as adjusting the viscosity of the ink to slow down the drying speed of the ink, or increasing the solubility of the coloring material and preventing clogging of the nozzles of the recording head. . Specific examples of the aqueous organic solvent include carbon such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol and n-pentanol. Number 1-5 alkyl alcohols. Amides such as dimethylformamide and dimethylacetamide. Ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; oxyethylene or oxy such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol and polypropylene glycol Propylene copolymer. Alkylene glycols in which an alkylene group contains 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, trimethylene glycol, triethylene glycol and 1,2,6-hexanetriol; Glycerin; trimethylolethane and trimethylolpropane. Lower alkyl ethers such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether and triethylene glycol monomethyl (or ethyl) ether; triethylene glycol dimethyl (or ethyl) ether and tetraethylene glycol dimethyl (or ethyl) ) Lower dialkyl ethers of polyhydric alcohols such as ethers; Alkanol amines such as monoethanolamine, diethanolamine and triethanolamine. Sulfolane, N-methyl-2-pyrrolidone, 2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone. The above is mentioned. These water-soluble organic solvents can be used alone or as a mixture.

  Next, the color ink used in the first embodiment will be described.

  The colored ink contains at least a color material and a liquid medium. When the colored ink comes into contact with the liquid composition according to this embodiment, it reacts with polyvalent metal ions derived from the polyvalent metal salt in the liquid composition. Here, “reaction” means that the coloring material in the colored ink aggregates or precipitates, or the thickening of the colored ink occurs.

  Examples of the color material used for the colored ink include pigments and dyes.

  As the pigment, any pigment such as an inorganic pigment and an organic pigment can be used, and specific examples include the following. That is, carbon black, C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 114, 128, 129, 151, 154 and 195. C. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 57 (Sr), 112, 122, 123, 168, 184 and 202. C. I. Pigment Blue 1, 2, 3, 15: 3, 15:34, 16, 22, and 60. C. I. Wat Blue 4 and 6 etc. The above is mentioned.

  When using the pigment described above as a coloring material, it is preferable to use a dispersant in order to stably disperse the pigment in the colored ink. Examples of the dispersant include a polymer dispersant and a surfactant-based dispersant. Specific examples of the polymer dispersant include, for example, polyacrylate, styrene-acrylic acid copolymer salt, styrene-methacrylic acid copolymer salt, and styrene-acrylic acid-acrylic acid ester copolymer salt. . Moreover, a styrene-maleic acid copolymer salt, an acrylic ester-maleic acid copolymer salt, a styrene-methacrylsulfonic acid copolymer salt, and a vinyl naphthalene-maleic acid copolymer salt are exemplified. Furthermore, (beta) -naphthalenesulfonic acid formalin condensate salt, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, etc. are mentioned.

  Among these, those having a weight average molecular weight of 1,000 to 30,000 are preferably used. Moreover, it is preferable to use a thing with an acid value of 100-430. Examples of the surfactant-based 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 0.5 parts by mass or more and 5.0 parts by mass or less when the pigment is 10 parts by mass.

  As the pigment, a so-called self-dispersing carbon black which can be self-dispersed by introducing a water-soluble group on the surface of the carbon black as described in JP-A-5-186704 can be used. . When self-dispersing carbon black is used, the amount of dispersant used can be reduced.

  When an ink using a pigment as a coloring material (pigment ink) comes into contact with the liquid composition, the pigment of the pigment ink reacts with the polyvalent metal ions in the liquid composition. That is, the pigment in the pigment ink rapidly aggregates and precipitates due to a salting-out action or the like. As a result, the fixing of the color material in the pigment ink to the recording medium is accelerated, and the occurrence of bleeding can be suppressed even when two or more different color inks are applied adjacently.

  As the dye, water-soluble dyes such as direct dyes, acid dyes, basic dyes and disperse dyes are preferably used.

  As the colored ink containing a dye, an ink in which the liquid composition reacts with the dye by contact with the liquid composition is preferable. That is, an ink that causes precipitation of a dye due to a salting out effect or formation of a poorly water-soluble or water-insoluble salt or compound due to a reaction between a polyvalent metal ion and the dye is preferable. Due to these actions or a combination of these actions, the fixing of the dye in the colored ink to the recording medium proceeds at a high speed. When such a dye comes into contact with the liquid composition, it easily reacts with the polyvalent metal salt in the liquid composition to form an insoluble salt or compound. Therefore, it is preferable to use a dye having at least one carboxyl group in the molecule. Specifically, although it is preferable to use the dye which has a structure as listed in the following exemplary compounds 1-30, this invention is not limited to these. In addition, M in exemplary compounds 1-5 is either an alkali metal, ammonium, or organic ammonium.

  As the color material to be contained in the colored ink, one kind may be used from among the pigment or the dye, or two or more kinds may be used in combination. The concentration of the color material is preferably 0.1% by mass or more with respect to the total amount of ink. Moreover, 20 mass% or less is preferable.

  As the liquid medium contained in the colored ink, the liquid medium exemplified in the liquid composition can be used.

  The liquid medium used in the first embodiment will be described.

  Further, in order to stabilize the solubility of the dye and the dispersibility of the pigment in the ink while keeping the pH value of the colored ink constant, a pH adjusting agent may be contained in the colored ink. Specific examples of the pH adjuster include inorganic acids such as nitric acid, sulfuric acid, and hydrochloric acid. Carboxylic acids such as acetic acid, propionic acid, lactic acid, malic acid, citric acid, gluconic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and pimelic acid. Hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide and ammonium hydroxide; Sulfates such as lithium sulfate, sodium sulfate, potassium sulfate and ammonium sulfate. Carbonates such as lithium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate and ammonium bicarbonate; Examples thereof include acetates and hydrochlorides such as lithium acetate, sodium acetate, potassium acetate and ammonium acetate.

  These pH adjusters may be contained in the liquid composition described above. These may be used alone in the liquid composition and the colored ink, but more preferably, two or more kinds of pH adjusters are selected and used in combination. These pH adjusters are preferably used in an amount of 0.1% by mass or more, more preferably 1% by mass or more, based on the total amount of the liquid composition. Moreover, it is preferable to use 10 mass% or less, and it is more preferable to use 8 mass% or less. By satisfying this condition, the pH can be kept more stable and the dissolution stability of the water-soluble dye contained in the colored ink can be improved. In addition, problems such as nozzle clogging can be prevented.

  In the liquid composition or in the colored ink used in combination therewith, in addition to the above components, various conventionally known general additives can be used in combination as required. For example, a viscosity modifier, an antifungal agent, an antiseptic, an antioxidant, an antifoaming agent, and a nozzle drying inhibitor such as urea can be used in combination as appropriate.

  The preferred range of physical properties of the liquid composition or the color ink used in combination with this is that the pH value around 25 ° C. is preferably 3 or more, more preferably 4 or more. Moreover, it is 12 or less, More preferably, it is 10 or less. The surface tension is preferably 10 mN / m (dyn / cm) or more, more preferably 15 mN / m (dyn / cm) or more. Further, it is preferably 60 mN / m (dyn / cm) or less, more preferably 50 mN / m (dyn / cm) or less. The viscosity is preferably 1 cps or more. Further, it is preferably 30 cps or less, more preferably 10 cps or less.

  In the first embodiment, the liquid composition and the colored ink are applied on a recording medium so that they form a contact state and react. The order of application may be the liquid composition first or the colored ink first. However, from the viewpoint of further improving the image density and fixability, it is preferable to apply the liquid composition after applying the color ink, and then apply the color ink again. By applying these on the recording medium so that a contact state between the liquid composition and the colored ink is formed, the good character quality, fixability, water resistance and bleeding suppression effect of the formed image can be improved. Achieved. This is because when the liquid composition and the colored ink come into contact with each other on the recording medium, the polyvalent metal ions resulting from the polyvalent metal salt constituting the liquid composition and the pigment and dye in the ink are mixed. It is considered that aggregation, precipitation, or thickening of the colored ink occurs.

  The recording medium used at this time is not particularly limited. However, when an image is formed on so-called plain paper such as copy paper or bond paper, the bleeding reduction effect of the present invention is noticeable. Therefore, it is preferable to use plain paper as the recording medium.

  In the case where the application of the liquid composition is performed prior to the application of the colored ink, the time from the time when the liquid composition is attached to the recording medium to the time when the colored ink is attached is not particularly limited. However, in order to make the present invention more effective, for example, it may be within 2 seconds, particularly preferably within 1 second. The same applies to the case where the liquid composition and the colored ink are applied on the recording medium in the reverse order.

  A case where recording is performed by applying the liquid composition and the colored ink onto a recording medium by the above method will be described. The applied amount per unit area of the colored ink and the liquid composition in the image forming area is 10 parts by mass when the applied amount of the colored ink is 10 parts by mass. Part or less. Here, the adjustment of the ratio of the applied amount of the colored ink and the liquid composition per unit area on the recording medium in the image forming region specifically includes the following method. For example, when the liquid composition and the colored ink are applied to the recording medium by an inkjet recording method, the number of pixels of the liquid composition to be deposited on the recording medium is the number of pixels of the colored ink to be deposited on the recording medium. Control to be 10 to 100%.

  By using the liquid composition according to the first embodiment, dissolution of the outermost protective layer of the recording head is suppressed, and stable ejection can be achieved. In the examination by the present inventors, the reason why such stable discharge is possible is considered as follows. The compound represented by the general formula (1) contained in the liquid composition suppresses decomposition of the polyvalent metal salt due to overheating of the anion ion. For this reason, the increase in the cation ion (polyvalent metal ion) concentration in the vicinity of the heater and the increase in alkalinity are suppressed, and the outermost surface protection made of a metal such as tantalum and / or a metal oxide provided on the heater. Dissolution of the membrane is suppressed. Therefore, disconnection of the heater is also suppressed.

  Examples of the ink jet recording apparatus using the liquid composition according to the first embodiment include the following ink jet recording apparatuses.

  That is, a liquid composition container that contains a liquid composition, a colored ink container that contains a colored ink, and an ink jet recording apparatus that discharges the liquid composition and the colored ink by a thermal ink jet recording method. The ink jet recording apparatus includes a recording head having a heater for applying thermal energy to the liquid composition and the colored ink in the flow path led from the liquid composition storing portion and the colored ink storing portion. In addition, there is provided means for applying a pulsed electric signal to the heater according to the recording information. Further, the heater includes an outermost surface protective layer containing a metal and / or a metal oxide. Here, in the case of an ink jet recording apparatus in which the metal and / or metal oxide is tantalum and / or an oxide of tantalum, it is preferable in that the remarkable effect of the present invention is exhibited.

  An ink jet recording apparatus that discharges ink by a thermal ink jet recording method will be described with reference to the drawings. An example of a head configuration which is a main part of the ink jet recording apparatus is shown in FIGS. 1 is a cross-sectional view of the recording head 13 along the ink flow path, and FIG. 2 is a cross-sectional view taken along the line AB of FIG. The recording head 13 is obtained by bonding a heating element substrate 15 to glass, ceramic, silicon, polysulfone, a plastic plate or the like having a flow path (nozzle) 14 through which ink passes. The heating element substrate 15 is formed of 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, particularly tantalum or an oxide of tantalum. It has the outermost surface protective layer 16-2 to be formed. In addition, electrodes 17-1 and 17-2 formed of aluminum, gold, aluminum-copper alloy, and the like, and a heating resistor layer 18 formed of a high melting point material such as hafnium boride, tantalum nitride, and tantalum aluminum are provided. Furthermore, it has a heat storage layer 19 formed of silicon oxide, aluminum oxide or the like, and a substrate 20 formed of a material with good heat dissipation such as silicon, aluminum, or aluminum nitride.

  In this ink jet recording apparatus, when a pulsed electric signal is applied to the electrodes 17-1 and 17-2 of the head 13, a region (heater) indicated by n of the heating element substrate 15 rapidly generates heat. At this time, bubbles are generated in the ink 21 in contact with the surface, and the meniscus 23 protrudes due to the pressure, and the ink 21 is ejected through the nozzles 14 of the recording head 13. The ejected ink becomes ink droplets 24 from the ejection orifice 22 and flies toward the recording medium 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.

Next, the γ value will be described. The γ value is a factor that represents the ratio of the energy that the thermal inkjet head actually inputs to the minimum required critical energy that can eject the ink or liquid composition. That is, when the pulse width applied to the thermal ink 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, if the thermal inkjet head uses Eth as the critical energy to the minimum necessary heater that can eject ink or liquid composition, and the input energy when actually driving is Eop, the γ value is It is given by (B).
γ = Eop / Eth (B)

The following two methods (1) and (2) are given as methods for obtaining a γ value suitable for discharging a liquid composition from the driving conditions of the thermal ink jet head.
(1) When the pulse width is fixed First, with the given pulse width, the thermal ink jet head finds and drives an appropriate voltage for discharging the liquid composition. Next, the voltage is gradually lowered to find a voltage at which the discharge of the liquid composition stops, and the minimum dischargeable voltage immediately before this voltage is defined as Vth. If the voltage actually used for driving is Vop, the γ value can be obtained by the following equation (C).
γ = (Vop / Vth) ² (C)
(2) When the voltage is fixed First, the thermal ink-jet head finds an appropriate pulse width for ejecting the liquid composition at a given voltage and drives it. Next, the pulse width is gradually shortened to find a pulse width at which the discharge of the liquid composition stops. The minimum pulse width that can be ejected immediately before this pulse width is defined as Pth. If the pulse width actually used in driving is Pop, the γ value can be obtained by the following equation (D).
γ = Pop / Pth (D)
The voltage value here is a voltage that is actually applied to the heater unit to cause the thermal ink jet heater to generate heat. Since the voltage applied from the outside of the head may drop due to a contact or wiring resistance, it cannot be used for calculating the γ value in a strict sense. However, when Vth and Vop are measured from the outside of the head, these voltage fluctuations are included in both values. Therefore, unless the voltage fluctuation is large, these values are used directly to calculate the γ value. Even if it is calculated, there is little error, and therefore the value obtained by this can be used as the γ 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 to the same γ value, but in reality, the square of V and P are simply related. Not. That is, electrical problems such as the pulse waveform not being rectangular, thermal problems such as heat diffusion around the heater differing when the pulse waveform is different, and heat flux from the heater to ink differing when the voltage is different, and the foaming state changes. This is due to problems peculiar to thermal ink jet. 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 (2) is defined as the γ value.

  For stable ejection of ink and liquid composition, it is common to drive the ink jet recording apparatus under conditions such that the γ value obtained as described above is about 1.1 to 2. .

  FIG. 4 shows an example of an ink jet recording apparatus incorporating the recording head described above. 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 the recording area by the recording head 65, and in the illustrated example, 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 a discharge recovery portion 64, and the blade 61 and the ink absorber 63 remove moisture, dust, and the like from the discharge port surface.

  Reference numeral 65 denotes a recording head that has discharge energy generating means and performs recording by discharging ink onto a recording medium facing the discharge port surface on which the discharge ports are arranged. Reference numeral 66 denotes a recording head mounted with the recording head 65. It is a carriage for moving. 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.

  51 is a paper feeding unit for inserting a recording medium, and 52 is a paper feed roller driven by a motor (not shown). With these configurations, the recording medium is fed to a position facing the 65 discharge port surface of the recording head, and is discharged to a discharge portion provided with a 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. To do. Along with this movement, the wiping is performed.

  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. Here, reference numeral 40 denotes a colored ink containing portion containing supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof. 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 colored ink container preferably has a liquid contact surface made of polyolefin, particularly polyethylene. The colored ink storage unit is referred to as a color ink storage unit when storing color ink, and is referred to as a black ink storage unit when storing black ink. Moreover, when accommodating a liquid composition, it is called a liquid composition accommodating part.

  The ink jet recording apparatus according to the first embodiment is not limited to the recording head and the ink cartridge separated as described above, but may be an integrated recording apparatus as shown in FIG. In FIG. 6, reference numeral 70 denotes a recording unit, in which a liquid composition container that stores a liquid composition, a color ink container that stores color ink, a black ink container that stores black ink, and the like are stored. ing. For example, when the storage portion is an ink storage portion, an ink absorber is stored, and the ink in the ink absorber is ejected as ink droplets from a head portion 71 having a plurality of orifices. Polyurethane is preferably used as the material for 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.

  An example of forming a color image by the ink jet recording method according to the first embodiment will be described with reference to FIG. For example, a recording apparatus in which five recording heads shown in FIG. 3 are arranged on a carriage 96 is used. Reference numerals 91, 92, 93, and 94 denote recording heads for ejecting color inks of yellow, magenta, cyan, and black, respectively. Reference numeral 95 denotes a head for discharging the liquid composition. The head is disposed in the above-described recording apparatus and ejects ink of each color according to a recording signal. Further, for example, prior to the discharge of each color ink, the liquid composition is adhered to at least an image forming portion where the ink adheres to the recording medium.

  FIG. 7 shows an example in which five recording heads are used. However, the present invention is not limited to this. As shown in FIG. 8, one recording head uses yellow 101, magenta 102, cyan 103 and black 104, and liquid. A case where the composition 105 is separated from the liquid flow path is also preferable. Of course, the heads may be arranged so that the recording order of each ink and liquid composition is opposite to the above order.

  Specific examples of the arrangement of the ink jet recording head suitably used in the first embodiment include three types as shown in FIGS. 9 to 11, reference numerals 111 to 114, 121 to 124, and 131 to 134 denote recordings for ejecting ink of each color of yellow (Y), magenta (M), cyan (C), and black (Bk), respectively. Head. Reference numerals 115, 125, and 135 denote recording heads for discharging the liquid composition (S). The recording heads are arranged on the carriage in the same manner as shown in FIG. 7 (depending on the configuration example). Each recording head is arranged in a recording apparatus as described above, and ejects ink of each color according to a recording signal. In addition, the liquid composition is attached to an image region where at least the ink of each color adheres to the recording medium before or after the liquid composition. Each recording head is moved in the direction of arrow (1) by the carriage, and the recording medium is moved in the direction of arrow (2) by a paper feed roller.

  First, in the first configuration example shown in FIG. 9, recording heads for S (115), Bk (114), C (113), M (112), and Y (111) are arranged in parallel on the carriage. Has been. The second configuration example shown in FIG. 10 includes a liquid composition and black ink recording heads arranged in parallel, and these recording heads in parallel and Y (121) arranged in series with each other. It consists of recording heads for M (122) and C (123). Here, the ejection volume per dot of each recording head is not necessarily the same, and the ejection volume per dot of each recording head is set so that optimum recording is performed depending on the composition of the liquid composition. (Vd) may be adjusted. Preferably, a configuration in which Vd of S, Y, M, and C is made the same and Bk is doubled is not limited thereto. Furthermore, in the third configuration example shown in FIG. 11, the discharge volumes for Bk (134), S (135), Bk (134), C (133), M (132), and Y (131) having the same discharge volume are used. The recording heads are arranged in parallel on the carriage, and the black ink discharge amount can be double the discharge amount of the other liquid composition and the color ink. In the configuration example shown in FIG. 11, the discharge volumes (Vd) of S, Bk, Y, M, and C are not necessarily the same.

[Second Embodiment]
Next, one specific embodiment of the present invention is referred to as a “second embodiment” and will be described below.

  The second embodiment refers to a color ink for thermal ink jet recording characterized by containing a compound represented by the general formula (1), a liquid medium, and a color material, and contact with the color ink. In this embodiment, a black ink that reacts with the color ink is used, and the color ink and the black ink are applied on a recording medium so that they form a contact state. In such an embodiment, the application of the liquid composition and the colored ink is performed by a thermal ink jet recording method.

  As the compound represented by the general formula (1) contained in the color ink, acetamide, propionic acid amide, butyramide, N-methylacetamide, and N-ethylacetamide are preferable. The color ink contains at least one selected from the compounds represented by the general formula (1). The total content of the compound represented by the general formula (1) contained in the color ink is preferably 1% by mass or more, and more preferably 1.75% by mass or more with respect to the total amount of the color ink. Moreover, it is preferable that it is 20 mass% or less with respect to the total amount of color inks, and it is more preferable that it is 7 mass% or less. By satisfying this condition, it is possible to extend the life of the superior head, and it is possible to discharge the color ink satisfactorily.

  The second embodiment aims to prevent bleeding between black ink and color ink. However, if the color ink is treated so as to have quick permeability to plain paper, it is effective for preventing bleeding between different color inks. Specifically, a surfactant is added to the color ink.

  The color ink used in the second embodiment will be described.

Examples of the color material used for the color ink include pigments and dyes.
Next, the color material contained in the color ink constituting the ink set according to the second embodiment will be described. Examples of the color material include direct dyes, acid dyes, basic dyes, disperse dyes, and pigments, but the color material can maintain solubility without reacting even when formulated with a polyvalent metal salt. preferable. As such a coloring material, those listed below can be used.

  For example, C.I. I. Acid Yellow 23; I. Acid Red 52, 289; I. Acid Blue 9; I. Reactive Red 180; C.I. I. Direct Blue 189, 199; C.I. I. Basic yellow 1, 2, 11, 13, 14, 19, 21, 25, 32, 33, 36, 51; I. C. Basic Orange 2, 15, 21, 22; I. B. Basic Red 1, 2, 9, 12, 13, 37, 38, 39, 92; I. C. basic violet 1, 3, 7, 10, 14; I. Basic blue 1, 3, 5, 7, 9, 19, 24, 25, 26, 28, 29, 45, 54, 65; C.I. I. B. Basic Green 1, 4; I. B. Basic Brown 1, 12; I. Basic black 2, 8, etc. are mentioned, but it is not limited to these. These water-soluble dyes may be used alone or in combination of two or more. Further, the concentration of these water-soluble dyes is preferably 0.1% by mass or more, and preferably 20% by mass or less, based on the total amount of the ink.

  Examples of the pigment include a dispersion pigment using a nonionic dispersion or an amino dispersion and an amino self-dispersion pigment.

  Even if the color ink contains the compound represented by the general formula (1), the pH of the ink does not change greatly, so that the aggregation and precipitation of the coloring material due to the pH change is unlikely to occur.

  The color ink preferably contains at least one surfactant in addition to the components described above. By containing the surfactant, it is possible to impart desired permeability and viscosity to the color ink. Specific examples of the surfactant include conventionally known surfactants such as an anionic surfactant, a cationic surfactant, and a nonionic surfactant. Among these, it is preferable to use a nonionic surfactant. The addition amount of these surfactants in the color ink is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, based on the total amount of the ink. Moreover, it is preferable that it is 10 mass% or less. By satisfying this condition, it is easy to obtain an appropriate ink viscosity that can provide the desired permeability.

  Next, the black ink used in the second embodiment will be described.

  The black ink includes a color material and a liquid medium, and reacts with the color ink by contact with the color ink. Specifically, it is preferable to use a colorant that reacts with the polyvalent metal ions resulting from the polyvalent metal salt in the color ink. The “reaction” here has the same meaning as described in the first embodiment.

  Examples of the color material used for the black ink include black color materials that can be used for the color ink of the first embodiment. These color materials may be used alone or in combination of two or more. The amount of these color materials added is preferably 0.1% by mass or more based on the total amount of ink. Moreover, it is preferable that it is 20 mass% or less.

  It is preferable to add a nonionic surfactant to the black ink. Nonionic surfactants used at this time include, for example, higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, aliphatic ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, and aliphatic amide ethylenes. Examples thereof include oxide adducts, higher alkylamine ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, fatty acid esters of polyhydric alcohols, and nonionic surfactants of fatty acid amides of alkanolamines. All of these are preferably used, but more preferably nonionics such as ethylene oxide adducts of higher alcohols, ethylene oxide adducts of alkylphenols, ethylene oxide-propylene oxide copolymers, ethylene oxide adducts of acetylene glycol, etc. A surfactant is used. Furthermore, the content of the nonionic surfactant contained in the black ink in which the number of added moles of the ethylene oxide adduct is preferably in the range of 4 to 20 is 0.1% by mass or more of the total amount of the ink. Is preferable, and is more preferably 0.2% by mass or more. Moreover, it is preferable to set it as 0.5 mass% or less, and it is more preferable to set it as 0.4 mass% or less. By satisfying this condition, it is easy to improve the bleeding suppression between the black ink and the color ink, and it is effective to reduce the density of the black ink at the boundary between the black ink and the color ink, so-called “white haze”. Easy to suppress. In addition, it is easy to maintain good ink ejection properties and print quality.

  The liquid medium used in the black ink and the color ink, the amount of addition thereof, the physical property value, and the like are the same as the values described in the first embodiment.

  In the second embodiment, the color ink and the black ink are applied on a recording medium so that they form a contact state and react.

  The recording medium used at this time is not particularly limited. However, when an image is formed on so-called plain paper such as copy paper or bond paper, the bleeding reduction effect of the present invention is noticeable. Therefore, it is preferable to use plain paper as the recording medium.

  As another aspect, there is a method in which the black ink and the color ink are applied so as to overlap each other on the recording medium, and the color ink is applied to the recording medium prior to the black ink (hereinafter referred to as the underlaying method). It is done. By performing the underlaying method, the bleeding between the black ink and the color ink can be further improved, and the white haze can be reduced. In the underlaying method, it is preferable that the time from when the color ink is adhered to the recording medium to when the black ink is adhered is within several seconds, particularly preferably within one second. Further, after applying the black ink, a mode of applying the color ink (upper method) may be used.

  In the underlaying method, the amount of black ink and color ink applied to the recording medium per unit area in the image forming area is 1 mass when the amount of black ink applied is 10 parts by mass. It is preferable to be at least 10 parts by mass. In this way, white haze in the obtained image is reduced, and uniformity is improved particularly in a solid image. The adjustment of the ratio of the applied amount of black ink and color ink per unit area on the recording medium in the image forming area can be specifically exemplified by the following method. For example, when black ink and color ink are applied by an ink jet recording method, the number of pixels of color ink deposited on the recording medium is 10 to 100% of the number of pixels of black ink deposited on the recording medium. The method of controlling is mentioned.

  By using the color ink according to the second embodiment of the present invention, dissolution of the outermost protective layer of the recording head is suppressed, and stable ejection can be achieved. In the examination by the present inventors, the reason why such stable discharge is possible is considered as follows. By the compound represented by the general formula (1) contained in the color ink, decomposition due to overheating of the anion ion of the polyvalent metal salt is suppressed. For this reason, the increase in the cation ion (polyvalent metal ion) concentration in the vicinity of the heater and the increase in alkalinity are suppressed, and the outermost surface protection made of a metal such as tantalum and / or a metal oxide provided on the heater. Dissolution of the membrane is suppressed. Therefore, disconnection of the heater is also suppressed.

  As an ink jet recording apparatus using the color ink and the black ink according to the second embodiment, for example, a recording apparatus in which four recording heads shown in FIG. 3 are arranged on a carriage can be used. FIG. 12 shows an example. These recording heads are supplied with ink from a color ink storage unit and a black ink storage unit as shown in FIG. Reference numerals 141, 142, 143, and 144 denote recording heads for ejecting yellow ink (Y), magenta ink (M), cyan ink (C), and black ink (Bk), respectively. The head is disposed in the recording apparatus described above, and, for example, ejects ink of each color according to a recording signal for ejecting ink of each color while moving the carriage in the direction of the arrow.

  FIG. 12 shows an example in which four recording heads are used. Of course, the present invention is not limited to this, and as shown in FIG. 13, the liquid flow paths of the black ink 154, the cyan ink 153, the magenta ink 152, and the yellow ink 151 may be divided by one recording head. preferable. As an example of a specific arrangement of the ink jet recording head suitably used in the second embodiment, there are two types as shown in FIGS. 14 and 15, reference numerals 161 to 164 and 171 to 174 denote recording heads for discharging various inks of yellow, magenta, cyan and black, respectively. The recording heads are arranged on the carriage in the same manner as shown in FIG. 12 (depending on the configuration example). Each recording head is disposed in the ink jet recording apparatus as described above, and ejects various inks according to a recording signal. Each recording head is moved in the direction of arrow (1) by the carriage, and the recording medium is moved in the direction of arrow (2) by a paper feed roller.

  First, in the configuration example shown in FIG. 14, recording heads for Bk (164), C (163), M (162), and Y (161) are arranged in parallel on the carriage. In the second configuration example shown in FIG. 15, the recording head for black ink (174) and this recording head are arranged in parallel and in series with each other C (173), M (172), Y (171) recording head. In FIG. 14, the present invention may be applied to a so-called line printer in which the carriage is fixed and the recording medium is moved in the direction of arrow (2) by a paper feed roller or the like.

  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. In the text, “parts” and “%” are based on mass unless otherwise specified.

  The preparation method of each liquid composition and colored ink is as follows.

<Method for preparing liquid composition>
First, the following components were mixed to dissolve the polyvalent metal salt. Then, pressure filtration was performed using a micro filter (manufactured by Fuji Film) having a pore size of 0.2 μm. In this way, liquid compositions 1 to 13 were prepared. The liquid compositions 1 to 10 correspond to examples, and the liquid compositions 11 to 13 correspond to comparative examples.
<Liquid composition 1>
-Magnesium nitrate 2.5 parts-Trimethylolpropane 5 parts-Acetamide 7 parts-Water 85.5 parts <Liquid composition 2>
-Magnesium nitrate 2.5 parts-Trimethylolpropane 5 parts-Acetamide 1.75 parts-Water 90.75 parts <Liquid composition 3>
-Magnesium nitrate 2.5 parts-Trimethylolpropane 5 parts-Butyramide 7 parts-Water 85.5 parts <Liquid composition 4>
-Magnesium nitrate 2.5 parts-Trimethylolpropane 5 parts-N-methylacetamide 7 parts-Water 85.5 parts <Liquid composition 5>
Calcium nitrate 2.8 parts Trimethylolpropane 5 parts Acetamide 7 parts Water 85.2 parts <Liquid composition 6>
・ Calcium nitrate 2.8 parts ・ Trimethylolpropane 5 parts ・ Butylamide 7 parts ・ Water 85.2 parts <Liquid composition 7>
・ Calcium acetate 2.7 parts ・ 1,2,6-hexanetriol 5 parts ・ Acetamide 7 parts ・ Water 85.3 parts <Liquid composition 8>
・ Calcium acetate 2.7 parts ・ 1,2,6-hexanetriol 5 parts ・ Butylamide 7 parts ・ Water 85.3 parts <Liquid composition 9>
-Magnesium acetate 2.4 parts-1,2,6-hexanetriol 5 parts-Acetamide 7 parts-Water 85.6 parts <Liquid composition 10>
-Magnesium acetate 2.4 parts-1,2,6-hexanetriol 5 parts-Butyramide 7 parts-Water 85.6 parts <Liquid composition 11>
-Magnesium nitrate 2.5 parts-Trimethylolpropane 5 parts-Water 92.5 parts <Liquid composition 12>
Calcium nitrate 2.8 parts Trimethylolpropane 5 parts Water 92.2 parts <Liquid composition 13>
・ Calcium acetate 2.7 parts ・ 1,2,6-hexanetriol 5 parts ・ Water 92.3 parts

<Preparation method of pigment ink>
The pigment ink was prepared by the following method.

<Black ink 1>
(Preparation of pigment dispersion 1)
After mixing 300 g of commercially available acidic carbon black “MA77” (pH 3, manufactured by Mitsubishi Chemical) into 1000 ml of water, 450 g of sodium hypochlorite (effective chlorine concentration: 12%) was added dropwise thereto at 100 to 105 ° C. The mixture was stirred for 10 hours to obtain a slurry. The obtained slurry was Toyo Filter Paper No. 2 (manufactured by Advantis), and the pigment particles were sufficiently washed with water to obtain a pigment wet cake. 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 to obtain a pigment dispersion (pH = 8 to 10). Further, this pigment dispersion was concentrated to a pigment concentration of 10% by mass. By the above method, a —COONa group was introduced on the surface of the carbon black to obtain a pigment dispersion 1 having such a self-dispersing carbon black.

(Preparation of ink)
The following components containing the pigment dispersion 1 were mixed, and further filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 3 μm to prepare a black ink 1.
-40 parts of the pigment dispersion liquid-8 parts of glycerin-5 parts of trimethylolpropane-4 parts of isopropyl alcohol-43 parts of water

<Black ink 2>
(Preparation of pigment dispersion 2)
-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 Heat to 70 ° C. in a bath to dissolve the resin component. To this solution, 15 parts of carbon black “MA-100” (pH 3.5, manufactured by Mitsubishi Chemical) and 5 parts of 2-propanol were added, premixed for 30 minutes, and then subjected to a dispersion treatment under the following conditions.
・ 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, a centrifugal treatment (12,000 rpm, 20 minutes) was performed to remove coarse particles to obtain a pigment dispersion 2 containing carbon black.

(Preparation of ink)
The following components containing the pigment dispersion 2 were mixed, and further filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 3 μm to prepare a black ink 2.
-Pigment dispersion 2 20 parts-Trimethylolpropane 5 parts-Diethylene glycol 10 parts-2-pyrrolidone 5 parts-Ethylene oxide adduct of acetylene glycol (acetylenol EH, manufactured by Kawaken Fine Chemicals) 0.2 part-Water 59.8 Part

<Yellow ink 1>
(Preparation of pigment dispersion 3)
・ Styrene-acrylic acid copolymer (acid value 200, average molecular weight 7,000)
5.5 parts, 1.0 part of monoethanolamine, 67.5 parts of ion-exchanged water, 5.0 parts of diethylene glycol The above components were mixed and heated to 70 ° C. in a water bath to dissolve the resin component. To this solution, C.I. I. 20 parts of Pigment Yellow 93 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 ・ Crushing media: Glass beads 1 mm 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 following components containing the pigment dispersion 3 were mixed, and further filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 3 μm to prepare yellow ink 1.
-Pigment dispersion 3 20 parts-Glycerol 15 parts-Diethylene glycol 10 parts-Ethylene oxide adduct of acetylene glycol (acetylene EH, manufactured by Kawaken Fine Chemicals) 0.3 part-Water 54.7 parts

<Magenta ink 1>
(Preparation of pigment dispersion 4)
・ Styrene-acrylic acid copolymer (acid value 200, average molecular weight 7,000)
5.5 parts, 1.0 part of monoethanolamine, 67.5 parts of ion-exchanged water, 5.0 parts of diethylene glycol The above components were mixed and heated to 70 ° C. in a water bath to 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 ・ Crushing media: Glass beads 1 mm 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.

(Preparation of ink)
The following components containing the pigment dispersion 4 were mixed, and further filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 3 μm to prepare magenta ink 1.
-Pigment dispersion 4 20 parts-Glycerol 15 parts-Diethylene glycol 10 parts-Ethylene oxide adduct of acetylene glycol (acetylene EH, manufactured by Kawaken Fine Chemicals) 0.3 part-Water 54.7 parts

<Cyan ink 1>
(Preparation of pigment dispersion 5)
・ Styrene-acrylic acid copolymer (acid value 200, average molecular weight 7,000)
5.5 parts, 1.0 part of monoethanolamine, 67.5 parts of ion-exchanged water, 5.0 parts of diethylene glycol The above components were mixed and heated to 70 ° C. in a water bath to dissolve the resin component. Furthermore, C.I. I. 20 parts of Pigment Blue 15: 3 and 1.0 part of isopropyl alcohol were added, premixing was performed for 30 minutes, and then a dispersion treatment was performed under the following conditions.
・ Disperser: Sand grinder ・ Crushing media: Glass beads 1 mm diameter ・ Filling rate of grinding media: 50% (volume)
-Crushing time: 3 hours Further, a centrifugal treatment (12,000 rpm, 20 minutes) was performed to remove coarse particles, whereby a pigment dispersion 5 was obtained.

(Preparation of ink)
The following components containing the pigment dispersion 5 were mixed and further filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 3 μm to prepare cyan ink 1.
-Pigment dispersion 5 20 parts-Glycerol 15 parts-Diethylene glycol 10 parts-Ethylene oxide adduct of acetylene glycol (acetylene EH, manufactured by Kawaken Fine Chemicals) 0.3 part-Water 54.7 parts

<Method for preparing dye ink>
The dye ink was prepared by the following method.

<Black ink 3>
The following components containing the exemplified compound 1 as a colorant were mixed, and further filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 0.2 μm to prepare a black ink 3.
・ Exemplary Compound 1 (wherein M is NH ⁴⁺ ) 2 parts ・ Diethylene glycol 10 parts ・ 2-pyrrolidone 5 parts ・ 2-propanol 5 parts ・ Sodium hydroxide 0.1 part ・ Water 77.9 parts

<Yellow ink 2>
The following components containing the exemplified compound 2 as a coloring material were used and dissolved, followed by pressure filtration using a microfilter (manufactured by Fuji Film) having a pore size of 0.2 μm to prepare yellow ink 2.
・ Exemplified compound 2 (M in the formula is NH ⁴⁺ ) 3 parts ・ Glycerin 7 parts ・ Diethylene glycol 5 parts ・ Urea 5 parts ・ Ethanol 2 parts ・ Water 78 parts

<Magenta ink 2>
The following components containing the exemplified compound 3 as a colorant were used, dissolved, and then filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 0.2 μm to prepare magenta ink 2.
・ Exemplary compound 3 (M in the formula is NH4 +) 3 parts ・ Glycerin 7 parts ・ Diethylene glycol 5 parts ・ Urea 5 parts ・ Ethanol 2 parts ・ Water 78 parts

<Cyan ink 2>
The following components containing the exemplified compound 4 as a colorant were used, dissolved, and then filtered under pressure using a microfilter (manufactured by Fuji Film) having a pore size of 0.2 μm to prepare cyan ink 2.
-Exemplified compound 4 (wherein M is NH ⁴⁺ ) 3 parts-Glycerol 7 parts-Diethylene glycol 5 parts-Urea 5 parts-Ethanol 2 parts-Water 78 parts Also contains the compound represented by general formula (1) The prepared color ink was adjusted as follows.

<Yellow ink 3>
・ C. I. Basic yellow 11 4 parts ・ Calcium nitrate 2.5 parts ・ Trimethylolpropane 5 parts ・ Acetamide 5 parts ・ Acetylenol 1 part ・ Ethanol 2 parts ・ 1,5-pentanediol 7 parts ・ Ethyleneurea 2 parts ・ Water 71.5 parts <Magenta ink 3>
・ C. I. Reactive Red 180 4 parts, calcium acetate 2.5 parts, trimethylolpropane 5 parts, acetamide 5 parts, acetylenol 1 part, ethanol 2 parts, 1,5-pentanediol 7 parts, ethylene urea 2 parts, water 71.5 Part <Cyan ink 3>
・ C. I. Acid Blue 9 4 parts, Magnesium nitrate 2.5 parts, Trimethylolpropane 5 parts, Acetamide 5 parts, Acetylenol 1 part, Ethanol 2 parts, 1,5-pentanediol 7 parts, Ethyleneurea 2 parts, Water 71.5 parts Separately from this, a color ink not containing the compound represented by the general formula (1) was prepared as follows.

<Yellow ink 4>
・ C. I. Basic yellow 11 4 parts ・ Calcium nitrate 2.5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol 1 part ・ Ethanol 2 parts ・ 1,5-pentanediol 7 parts ・ Ethyleneurea 2 parts ・ Water 76.5 parts <Magenta ink 4 >
・ C. I. Reactive Red 180 4 parts, calcium acetate 2.5 parts, trimethylolpropane 5 parts, acetylenol 1 part, ethanol 2 parts, 1,5-pentanediol 7 parts, ethylene urea 2 parts, water 76.5 parts <Cyan ink 4>
・ C. I. Acid Blue 9 4 parts, Magnesium nitrate 2.5 parts, Trimethylolpropane 5 parts, Acetylenol 1 part, Ethanol 2 parts, 1,5-pentanediol 7 parts, Ethyleneurea 2 parts, Water 76.5 parts

(Evaluation and evaluation criteria)
<Evaluation test>
The evaluation test is shown below.

[Evaluation 1]
Durability was evaluated using the liquid compositions 1 to 13, yellow inks 3 and 4, magenta inks 3 and 4, and cyanine inks 3 and 4. For the evaluation, an inkjet recording apparatus having an ink cartridge (BC-02, manufactured by Canon Inc.) having an on-demand type multi-recording head that discharges a liquid composition by applying thermal energy according to a recording signal to the ink was used. . The outermost protective layer on the recording head heater is made of tantalum and tantalum oxide. Using the above apparatus, the liquid composition was measured at a driving frequency of 6,250 Hz, a driving voltage of 24.6 V, Pth was actually measured, and a Pop (driving pulse) corresponding to a γ value = 1.2 was applied and discharged. Ink ejecting 2 × E ⁸ shots from each outlet from the recording head was evaluated reduction of the outermost surface protective layer at this time of the heater. The results are shown in Table 1 below.

  As is clear from Table 1, the liquid composition and color ink shown in the examples of the present invention can sufficiently suppress the decrease in the outermost protective layer of the heater as compared with the liquid compositions shown in the comparative examples. ing. For this reason, the life of the head can be extended and stable ejection can be achieved.

[Evaluation 2]
Each color ink and each of the liquid compositions 1 to 10 were combined as shown in Table 2 to prepare an ink set, and recording was performed on recording paper. Also, an ink set was created by combining black ink 2, yellow ink 3, magenta ink 3, and cyan ink 3, and recording was performed on recording paper.

  The ink jet recording apparatus used is a recording apparatus (BJC700J, manufactured by Canon) having the same configuration as shown in FIG. Using such a recording apparatus, an image was formed using the five recording heads shown in FIG. At this time, the liquid composition was preliminarily deposited on the recording paper, and then the colored ink was adhered. Further, the position where the liquid composition was applied onto the recording paper was adjusted so as to be exactly overlapped with the position where the colored ink was applied onto the recording paper. Two types of recording paper, PB paper (manufactured by Canon) and XEROX 4024 paper (manufactured by Xerox), were used.

(1) Image print quality (feathering)
Alphanumeric characters (12 points) were printed using each ink set. After printing, it was allowed to stand for 1 hour, and the sharpness of the characters and the degree of occurrence of whiskers on the edges of the characters were visually evaluated. As a result, in any combination, the obtained characters were sharp and almost no whiskers (feathering) occurred.

(2) Bleeding Using each ink set, first, a solid part was printed with a liquid composition. Immediately thereafter, a solid portion was printed with black ink on the solid portion of the liquid composition. Immediately thereafter, a solid portion was printed with yellow, magenta, or cyan ink on the solid portion of the liquid composition so as to be adjacent to the solid portion of the black ink. The boundary between the black ink and the solid portion of the color ink obtained as described above was visually observed, and bleeding between each colored ink was evaluated. As a result, there was almost no occurrence of bleeding in any combination.

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. FIG. 5 is a perspective view showing a recording unit in which a plurality of recording heads are arranged. It is a perspective view of another recording head used for the present invention. FIG. 3 is a diagram illustrating a first configuration diagram of a recording head. FIG. 5 is a diagram illustrating a second configuration diagram of the recording head. FIG. 10 is a diagram illustrating a third configuration diagram of the recording head. FIG. 5 is a perspective view showing a recording unit in which a plurality of recording heads are arranged. It is a perspective view of another recording head used for the present invention. FIG. 10 is a diagram illustrating a fourth configuration example of a recording head. It is a figure which shows the 5th structural example of a recording head.

Explanation of symbols

13 Recording head 14 Ink groove (nozzle)
DESCRIPTION OF SYMBOLS 15 Heat generating 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 23 Meniscus 24 Ink droplet 25 Recording medium 26 Multi Groove (multi nozzle)
27 Glass plate 28 Heat generating head 40 Colored ink container (color ink container, black ink container) or liquid composition container 42 Plug 44 Ink absorber 45 Ink cartridge 51 Paper feed part 52 Paper feed roller 53 Paper discharge Roller 61 Blade 62 Cap 63 Ink absorber 64 Discharge recovery part 65 Recording head 66 Carriage 67 Guide shaft 68 Motor 69 Drive belt 70 Recording unit 71 Head part 72 Atmospheric communication port 80 Ink flow path 81 Orifice plate 82 Vibration plate 83 Piezoelectric element 84 Substrate 85 Discharge port 91 Yellow ink recording head 92 Magenta ink recording head 93 Cyan ink recording head 94 Black ink recording head 95 Liquid composition recording head 96 Carriage 101 Yellow ink flow path 102 Maze Tin ink flow path 103 Cyan ink flow path 104 Black ink flow path 105 Liquid composition flow path 111 Yellow ink recording head 112 Magenta ink recording head 113 Cyan ink recording head 114 Black ink recording head 115 Liquid composition recording head 121 Yellow ink recording head 122 Magenta ink recording head 123 Cyan ink recording head 124 Black ink recording head 125 Liquid composition recording head 131 Yellow ink recording head 132 Magenta ink recording head 133 Cyan ink recording head 134 Black ink recording head 135 Liquid composition recording head 141 Yellow ink recording Head 142 Magenta ink recording head 143 Cyan ink recording head 144 Black ink recording head 145 151 151 Yellow ink flow path 152 Magenta ink flow path 153 Cyan ink flow path 154 Black ink flow path 161 Yellow ink recording head 162 Magenta ink recording head 163 Cyan ink recording head 164 Black ink recording head 171 Yellow ink recording head 172 Magenta ink recording Head 173 Cyan ink recording head 174 Black ink recording head

Claims (19)

A liquid composition for thermal ink jet recording comprising water, a polyvalent metal salt, and a liquid medium, comprising a compound represented by the following general formula (1): Composition.
General formula (1)

(In the formula, R ₁ and R ₂ represent an alkyl group.)   The thermal inkjet recording liquid according to claim 1, wherein the compound represented by the general formula (1) is at least one selected from acetamide, propionic acid amide, butyramide, N-methylacetamide, and N-ethylacetamide. Composition.   The thermal ink jet recording liquid composition according to claim 1, wherein the polyvalent metal salt is at least one selected from a polyvalent metal salt of nitric acid or a polyvalent metal salt of acetic acid.   A thermal ink jet recording ink comprising a combination of the liquid composition according to any one of claims 1 to 3 and a colored ink that reacts with the liquid composition upon contact with the liquid composition. set.   A liquid composition container that contains the liquid composition according to any one of claims 1 to 3, and a colored ink container that contains a colored ink that reacts with the liquid composition by contact with the liquid composition. An ink cartridge for thermal ink jet recording, comprising:   A liquid composition storage unit that stores the liquid composition according to claim 1, and a recording head for discharging the liquid composition by a thermal ink jet recording method. Thermal inkjet recording device.   And a colored ink containing portion for containing a colored ink that reacts with the liquid composition by contact with the liquid composition, and a recording head for discharging the colored ink by a thermal ink jet recording method. The thermal ink jet recording apparatus according to claim 6.   The thermal ink jet recording apparatus according to claim 6 or 7, wherein the recording head includes a heater including an outermost surface protective layer containing a metal and / or a metal oxide.   The thermal ink jet recording apparatus according to claim 8, wherein the metal and / or metal oxide is tantalum and / or an oxide of tantalum. A thermal ink jet recording color ink comprising water, a polyvalent metal salt, a liquid medium, and a color material, comprising a compound represented by the following general formula (1): Color ink for recording.
General formula (1)

(In the formula, R ₁ and R ₂ represent an alkyl group.)   The color ink for thermal inkjet recording according to claim 10, wherein the color ink for thermal inkjet recording is at least one selected from yellow ink, magenta ink, and cyan ink.   The thermal inkjet recording according to claim 10 or 11, wherein the compound represented by the general formula (1) is at least one selected from acetamide, propionic acid amide, butyramide, N-methylacetamide, and N-ethylacetamide. Color ink.   The color ink for thermal ink jet recording according to any one of claims 10 to 12, wherein the polyvalent metal salt is at least one selected from a polyvalent metal salt of nitric acid or a polyvalent metal salt of acetic acid.   A thermal ink jet recording color ink according to any one of claims 10 to 13, and a black ink that reacts with the color ink by contact with the color ink. Ink set.   A color ink containing portion for containing the color ink for thermal ink jet recording according to any one of claims 10 to 13, and a black ink containing portion for containing a black ink that reacts with the color ink by contact with the color ink. An ink cartridge for thermal ink jet recording, comprising:   A color ink containing portion for containing the color ink for thermal ink jet recording according to any one of claims 10 to 13, and a recording head for discharging the color ink by a thermal ink jet recording method. A thermal ink jet recording apparatus.   And a black ink containing portion containing black ink that reacts with the color ink by contact with the color ink, and a recording head for discharging the black ink by a thermal ink jet recording method. The thermal ink jet recording apparatus according to claim 16.   The thermal ink jet recording apparatus according to claim 16 or 17, wherein the recording head includes a heater including an outermost surface protective layer containing a metal and / or a metal oxide.   The thermal ink jet recording apparatus according to claim 18, wherein the metal and / or metal oxide is tantalum and / or an oxide of tantalum.

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