JPH0820159A - Liquid composition, ink set and image forming method using the same - Google Patents

Abstract

(57) [Summary] [Purpose] In inkjet recording on plain paper, both good fixing properties and print quality are achieved, sufficient image density and solid image uniformity are improved, image bleeding is prevented, color reproducibility and Solves problems such as high definition and complete water resistance. [Structure] At least one selected from the cationic compounds represented by the following general formulas (I) to (III) is solubilized in water using a water-soluble organic solvent, and contains a water-soluble cationic interface. A liquid composition containing an activator, an ink set using the liquid composition, and an image forming method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for obtaining a water-resistant image by reducing bleeding that occurs when forming a color image on plain paper, and is most preferably used for image formation using an ink jet recording system. The present invention relates to a liquid composition, an ink set using the liquid composition, and an image forming method using the ink set.

[0002]

2. Description of the Related Art An ink jet recording method is one in which a droplet of ink is ejected and the ink is adhered to a recording medium such as paper for recording. In particular, Japanese Patent Publication No. 61-59911, Japanese Patent Publication No. 61-59912, and Japanese Patent Publication No. 61-5.
According to the ink jet recording method of the type disclosed in Japanese Patent No. 9914, in which an electrothermal converter is used as the ejection energy supply means and thermal energy is applied to ink to generate bubbles, the droplets are ejected. High-density multi-orifice can be easily realized, and high-resolution and high-quality images can be recorded at high speed.

However, the ink used in the conventional ink jet recording method contains water as a main component and contains a water-soluble high-boiling point solvent such as glycol for the purpose of preventing drying and preventing nozzle clogging. Therefore, it is estimated that when recording on plain paper using such ink, sufficient fixability may not be obtained, or due to uneven distribution of fillers and sizing agents on the recording paper surface. This causes a problem such as the occurrence of a non-uniform image. or,
In particular, when trying to obtain a color image, the inks of a certain color are successively superposed before the ink of a certain color is fixed on the recording paper. There is a problem that they are not uniformly mixed (hereinafter, this phenomenon is called bleeding) and a satisfactory image cannot be obtained.

On the other hand, as a means for improving the fixing property, Japanese Patent Application Laid-Open No. 55-65269 discloses a method of adding a compound such as a surfactant which enhances the permeability to ink. Further, JP-A-55-66976 discloses the use of an ink mainly composed of a volatile solvent. However, although the former method of adding a surfactant or the like to the ink increases the permeability of the ink into the recording paper and improves the fixability and bleeding of the ink to some extent, the coloring material in the ink is Since it penetrates deeply, inconveniences such as a decrease in image density and saturation occur. In addition, the ink spreads in the horizontal direction, resulting in problems such as a decrease in edge sharpness and a decrease in resolution. On the other hand, in the case of the latter method using an ink mainly composed of a volatile solvent, in addition to the same inconvenience as in the former case, clogging occurs due to evaporation of the solvent in the nozzle portion of the recording head. It was easy to do and was not preferable.

Further, in order to improve the above-mentioned problems, there has been proposed a method of depositing a liquid for improving an image in advance on a recording medium before ejecting ink. For example, in JP-A-63-29971, an ink containing an anionic dye is prepared by depositing a liquid containing an organic compound having two or more cationic groups per molecule on a recording medium. The method of recording is disclosed in.
Further, JP-A-64-9279 discloses a method in which an acidic liquid containing succinic acid or the like is deposited on a recording medium and then recording is performed with an ink containing an anionic dye. Further, Japanese Patent Application Laid-Open No. 64-63185 discloses a method of applying a liquid insolubilizing a dye prior to ink recording.

However, in any of the above-mentioned methods, since the bleeding and water resistance of the image are improved by precipitating the dye itself, the effect of suppressing bleeding between the color inks described above is insufficient, and the precipitation Since the dyes are likely to be unevenly distributed on the recording paper, the coverage of the recording paper on the pulp fibers is poor and the uniformity of the image is deteriorated.

[0007]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to solve the following five problems in view of the above circumstances. That is, the following two points can be cited as problems in performing inkjet recording on plain paper. Print quality should be good while having good fixability. Sufficient image density is obtained and the solid image uniformity is high. In addition to the above-mentioned points, the following three points can be raised especially when forming a color image on plain paper. Prevent bleeding. Good color reproducibility and high-definition images can be obtained. Make the recorded image completely waterproof.

[0008]

The above object can be achieved by the present invention described below. That is, the present invention is a liquid composition containing at least a cationic substance, wherein at least one selected from the cationic compounds represented by the following general formulas (I) to (III) is water-soluble by using a water-soluble organic solvent. A liquid composition characterized by being solubilized and contained in, and containing a water-soluble cationic surfactant,
It is an ink set using these liquid compositions and an image forming method using the ink set. [In the above general formula, R represents an alkyl group having 18 or more carbon atoms, and X represents Cl or Br. ]

[0009]

The function of the liquid composition containing the cationic substance according to the present invention will be described with reference to the drawings. When the liquid composition containing the cationic substance according to the present invention is mixed with the ink containing the anionic compound and mixed with the ink on the recording paper or at the position where the ink penetrates into the recording paper, the liquid composition shown in FIG. As shown, as the first step of the reaction, a low molecular weight component of the cationic substance contained in the liquid composition, for example, a water-soluble cationic surfactant and an anionic compound in the ink are used. And are associated with each other by an ionic interaction, and a coloring material such as a dye aggregates instantaneously and separates from the solution phase.

Next, in the second step of the reaction, the association product of the anionic compound and the low molecular weight cationic substance is adsorbed by the high molecular weight cationic component contained in the liquid composition. The size of the agglomerates thus generated is further increased (d), and it becomes difficult for the agglomerates to enter the gaps between the fibers of the recording paper. As a result, solid-liquid separation occurs, and agglomerates containing coloring materials such as dyes remain on the recording paper, and only the liquid portion permeates into the recording paper (e), which improves the printing quality and the fixing property. Compatibility is achieved. At the same time, the viscosity of the aggregate formed by the low molecular weight component of the cationic substance, the anionic compound and the high molecular weight component of the cationic substance generated by the mechanism as described above increases, and the movement of the liquid medium Since they do not move together with each other, even when adjacent dots are formed of different color inks as in the conventional full-color image formation described above, they do not mix with each other and bleeding does not occur. Further, since the above-mentioned aggregate is essentially insoluble in water, the water resistance of the formed image is perfect.

Further, in carrying out the present invention, when a colorless liquid composition is adhered to a recording medium using an ink jet recording head, a cationic polymer substance having a large molecular weight as in the prior art is used. Since it does not need to be provided, the viscosity of the liquid can be lowered, which is advantageous for ejection characteristics. Furthermore, since it is not necessary to use a polyvalent metal salt as in the case of the prior art, kogation, which is a peculiar problem that occurs when using a thermal inkjet recording head, can be prevented, resulting in high reliability. A stable record can be achieved by sex.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments of the present invention. The liquid composition according to the present invention is a liquid composition containing at least a cationic substance, and is selected from high molecular weight cationic compounds having a specific structure solubilized in water using a water-soluble organic solvent. At least one, and characterized by containing a low molecular weight water-soluble cationic surfactant,
More preferably, a specific monohydric alcohol such as ethanol is used as the water-soluble organic solvent. That is, since the specific cationic compound capable of exhibiting the excellent effect of the present invention is difficult to dissolve in water, it is used after being solubilized in water using a water-soluble organic solvent.

The ink set according to the present invention is characterized by using the liquid composition of the present invention as described above. Preferably, at least an anion is used as a colored ink for recording used together with the liquid composition. An ink containing a dye containing a functional group or an ink containing at least an anionic compound and a pigment is used.

The action and effect of the liquid composition according to the present invention are as described above. First, a water-soluble cationic surfactant agent which is a low molecular weight cationic substance contained in the liquid composition and an ink are contained in the ink. The water-soluble dye containing at least an anionic group, or the anionic compound used together with the pigment first forms an associated body by ionic interaction, and the dye or the like aggregates. In addition, the formation reaction rate of this aggregate needs to be extremely high.

As the water-soluble cationic surfactant used in this case, it is preferable to use the following compounds having a molecular weight of about 100 to 400. Specifically, for example,
Primary, secondary and tertiary amine salt type compounds, specifically,
Hydrochloric acid salts such as laurylamine, coconut amine, rosin amine, etc .; quaternary ammonium salt type compounds, specifically, lauryl trimethyl ammonium chloride,
Cetyltrimethylammonium chloride, lauryldimethylbenzylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, etc .; pyridinium salt type compounds, specifically cetylpyridinium chloride, cetylpyridinium bromide, etc .;
Preferred are imidazoline type cationic compounds, specifically 2-heptadecenyl-hydroxyethyl imidazoline and the like; ethylene oxide adducts of higher alkyl amines, specifically dihydroxyethyl lauryl amine and the like.

Further, in the present invention, other p
An amphoteric surfactant that exhibits a cationic property in the H region is also preferably used as the cationic substance. Specifically, for example, an amino acid type amphoteric surfactant; R-NH-CH ₂
Compound of -CH ₂ -COOH type; betaine compounds,
Specifically, in addition to carboxylate type amphoteric surfactants such as lauryl dimethyl betaine and lauryl dihydroxyethyl betaine, amphoteric surfactants such as sulfuric acid ester type, sulfonic acid type and phosphoric acid ester type are listed. Of course, when these amphoteric surfactants are used, the liquid composition according to the present invention is adjusted so as to have a pH below their isoelectric point, or this liquid composition is mixed with ink on the recording medium. In this case, it is necessary to adjust the pH so that the pH is below the isoelectric point. In the above, examples of low molecular weight cationic compounds are given as the cationic substance, but it goes without saying that the present invention is not necessarily limited to these.

Next, as described above, the aggregate formed instantly from the low molecular weight cationic substance in the liquid composition and the anionic compound in the ink is represented by the following general formula (I). To (III) are adsorbed in the molecule by the high molecular weight cationic compound in the liquid composition, and the size of the aggregate containing the dye or the like produced by association is further increased, and the aggregate is used as a recording paper. It becomes difficult to get into the gaps between the fibers, and solid-liquid separation is achieved.

Therefore, the liquid composition according to the present invention contains a cationic compound having the structures of the following general formulas (I) and (III) as an essential component. [In the above general formula, R represents an alkyl group having 18 or more carbon atoms, and X represents Cl or Br. ]

Preferred specific examples of the above-mentioned cationic compound include quaternary ammonium salt type compounds represented by the above general formulas (I), (II) and (III), for example, stearyl trimethyl ammonium chloride and distearyl dimethyl ammonium. Examples thereof include chloride, stearylbenzyldimethylammonium chloride, behenyltrimethylammonium chloride and the like, but are not limited thereto.

The amount of the above-mentioned cationic substance contained in the liquid composition of the present invention is 0.0 on a weight basis.
The preferable range is 5 to 20% by weight, and the more preferable range is 0.5 to 10% by weight, but it is necessary to determine the optimum range depending on the combination of substances used. The amount of the water-soluble surfactant is preferably 0.05% by weight to 10% by weight.

Next, the water-soluble organic solvent constituting the liquid composition according to the present invention may be any one as long as it can solubilize the above-mentioned cationic compound in water. Monohydric alcohols such as alcohol, n-butyl alcohol and isobutyl alcohol are particularly preferably used. Other water-soluble organic solvents used include amides such as dimethylformamide and dimethylacetamide, ketones such as acetone,
Tetrahydrofuran, dioxane and other ethers, polyethylene glycol, polypropylene glycol and other polyalkylene glycols, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, Alkylene glycols such as diethylene glycol, lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethanol, isopropyl alcohol, n-butyl alcohol,
In addition to monohydric alcohols such as isobutyl alcohol, glycerin, N-methyl-2-pyrrolidone, 1,3-dimethyl-imidazolidinone, triethanolamine, sulfolane, dimethylsulfoxide and the like can be mentioned. The content of the water-soluble organic solvent is not particularly limited, but 5 to 60% by weight, more preferably 5% by weight based on the total weight of the liquid composition.
-40% by weight is a suitable range.

In addition to the above, the liquid composition according to the present invention may further contain a viscosity adjusting agent, a pH adjusting agent, an antiseptic agent, if necessary.
Additives such as various surfactants, antioxidants, and evaporation promoters may be appropriately mixed. The selection of the surfactant is particularly important in adjusting the permeability of the liquid into the recording medium. The liquid composition according to the present invention is more preferably colorless, but almost no color is formed when only the liquid composition is recorded on the recording medium, and each color when mixed with the ink on the recording medium or the like. It may be a light color that does not change the color tone of the ink. Furthermore, as a suitable range of various physical properties of the liquid composition as described above, at about 25 ° C., the pH is 3 to 12, preferably 3 to 8, more preferably 3 to 5, and the surface tension is 10 to 60 dyn. / Cm, more preferably 10-40d
yn / cm, and the viscosity is 1 to 30 cps. It is what As will be described later, the surface tension of the liquid composition according to the present invention is preferably lower than the surface tension of the ink used with the liquid composition.

Next, the ink constituting the ink set according to the present invention will be described. The ink used in the present invention preferably uses a water-soluble dye containing an anionic group as a coloring material or, when a pigment is used as a coloring material, a combination of anionic compounds.
In addition to the above inks used in the present invention, water, a water-soluble organic solvent and other components such as a viscosity adjusting agent, a pH adjusting agent, a preservative, a surfactant, an antioxidant, etc. Are included as needed.

The water-soluble dye containing an anionic group used in the present invention includes a color index (COLO).
There is no particular limitation as long as it is a water-soluble acid dye, direct dye or reactive dye described in UR INDEX).
Further, even those not described in the color index are not particularly limited as long as they have an anionic group such as a sulfone group and a carboxyl group. Of course, the water-soluble dyes referred to herein include those whose solubility is pH-dependent.

As the water-soluble organic solvent contained in the ink containing the water-soluble dye as the color material as described above,
The water-soluble organic solvent used in the liquid composition according to the present invention described above can be similarly used. The same applies to the preferable range of the content of these water-soluble organic solvents in the ink. Further, the preferable physical property range of the ink is exactly the same as that of the liquid composition. However, regarding the surface tension of the ink, it is preferable that the surface tension of the ink is higher than the surface tension of the liquid composition according to the present invention, because it may be effective in carrying out the image forming method according to the present invention. This is because if the surface tensions of the two are adjusted in this manner, for example, in the printing process, the liquid composition ejected first can have an even wettability of the ink ejected later on the recording medium. It is thought that it will be exerted, but the details are not clear.

When a pigment is used as the coloring material of the ink used in the present invention, the amount of the pigment is 1 to 20% by weight, preferably 2 to 12% by weight based on the total weight of the ink. Used in the range. Specific examples of the pigment used in the present invention include carbon black used as a black ink. For example, carbon black produced by a furnace method or a channel method may be used. Diameter is 15 to 40 mμ, specific surface area by BET method is 50 to 300 m ² / g, DBP oil absorption is 40 to 1
Those having characteristics such as 50 ml / 100 g, volatile content of 0.5 to 10%, and pH value of 2 to 9 are preferably used.
Examples of commercially available products having such characteristics include No.
2300, No. 900, MCF88, No. 33, N
o. 40, No. 45, No. 52, MA7, MA8,
No. 2200B (Made by Mitsubishi Kasei), RAVEN12
55 (Made in Colombia), REGAL400R, RE
GAL330R, REGAL660R, MOGUL L
(Above made by Cabot), Color Black FW
1, COLOR Black FW18, Color
Black S170, Color Black S1
50, Printex 35, Printex U (all manufactured by Degussa) and the like, and any of them can be preferably used.

As the pigment used for the yellow ink, for example, C.I. I. Pigment Yellow
w 1, C.I. I. Pigment Yellow 2,
C. I. Pigment Yellow 3, C.I. I.
Pigment Yellow 13, C.I. I. Pig
ment Yellow 16, C.I. I. Pigmen
Examples of pigments used in magenta ink include C.I. I. Pig
ment Red 5, C.I. I. Pigment Re
d 7, C.I. I. Pigment Red 12, C.I.
I. Pigment Red 48 (Ca), C.I. I.
Pigment Red 48 (Mn), C.I. I. Pi
gment Red 57 (Ca), C.I. I. Pigm
entRed 112, C.I. I. Pigment Re
d122 and the like. Examples of the pigment used for the cyan ink include C.I. I. Pigment Bl
ue 1, C.I. I. Pigment Blue 2,
C. I. Pigment Blue 3, C.I. I. Pig
ment Blue 15: 3, C.I. I. Pigmen
t Blue 16, C.I. I. Pigment Blu
e 22, C.I. I. Vat Blue 4, C.I. I. V
Examples thereof include at Blue 6 and the like, but the present invention is not limited thereto. In addition to the above, it is of course possible to use pigments newly produced for the present invention.

As the dispersant to be contained in the ink when a pigment is used, any water-soluble resin can be used, but the weight average molecular weight is 1,00.
The range of 0 to 30,000 is preferable, and the range of 3,000 to 15,000 is more preferably used. Specific examples of such a dispersant include styrene, styrene derivatives, vinylnaphthalene, vinylnaphthalene derivatives, α, β-ethylenically unsaturated carboxylic acid aliphatic alcohol esters, acrylic acid, acrylic acid derivatives, and maleic acid. , Maleic acid derivative, itaconic acid, itaconic acid derivative, fumaric acid, fumaric acid derivative, vinyl acetate, vinylpyrrolidone, acrylamide,
And a block copolymer composed of at least two or more monomers (at least one of which is a hydrophilic monomer) selected from derivatives thereof, a random copolymer, a graft copolymer, or a copolymer thereof. Salt etc. are mentioned. Alternatively,
Natural resins such as rosin, shellac and starch can also be preferably used. These resins are alkali-soluble resins that are soluble in an aqueous solution in which a base is dissolved.
The water-soluble resin used as the pigment dispersant is preferably contained in the range of 0.1 to 5% by weight based on the total weight of the ink.

Particularly, in the case of an ink containing the above-mentioned pigment, it is preferable that the entire ink is adjusted to be neutral or alkaline. This is preferable because the solubility of the water-soluble resin used as the pigment dispersant can be improved and the ink can be further excellent in long-term storage stability. However, in this case, it may cause corrosion of various members used in the inkjet recording apparatus. Therefore, it is preferable that the pH range is 7 to 10. Examples of the pH adjuster used in this case include various organic amines such as diethanolamine and triethanolamine, inorganic alkali agents such as sodium hydroxide, lithium hydroxide, and alkali metal hydroxides such as potassium hydroxide, Examples include organic acids and mineral acids. The water-soluble resin, which is a pigment and a dispersant as described above, is dispersed or dissolved in an aqueous liquid medium.

A suitable aqueous liquid medium in the ink containing the pigment used in the present invention is a mixed solvent of water and a water-soluble organic solvent, and the water is not general water containing various ions, It is preferable to use ion-exchanged water (deionized water).

Examples of the water-soluble organic solvent used by mixing with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol and the like. Alkyl alcohols having 1 to 4 carbon atoms; amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylenes such as polyethylene glycol and polypropylene glycol Glycols; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol,
1,2,6-hexanetriol, thiodiglycol,
Alkylene glycols in which the alkylene group such as hexylene glycol and diethylene glycol contains 2 to 6 carbon atoms; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) Lower alkyl ethers of polyhydric alcohols such as ethers; N-methyl-2-pyrrolidone,
2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned. Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether are preferable.

The content of the above water-soluble organic solvent in the ink is generally in the range of 3 to 50% by weight, preferably 3 to 40% by weight based on the total weight of the ink.
Also, the content of water used is 1 of the total weight of the ink.
The range is 0 to 90% by weight, preferably 30 to 80% by weight.

Further, the ink containing the pigment used in the present invention contains, in addition to the above-mentioned components, a surfactant, a defoaming agent, and a defoaming agent in order to obtain an ink having desired physical properties, if necessary. Preservatives and the like can be added as appropriate. In addition to the above pigments, water-soluble dyes such as those described above can be added as appropriate as a coloring material. Further, similarly to the above, when using an ink containing a pigment, it is preferable that the surface tension of the ink is larger than the surface tension of the liquid composition according to the present invention. It is preferable to adjust the surface tension of the ink in such a manner as described above.

As a method for producing an ink containing a pigment as described above, first, the pigment is added to an aqueous medium containing at least a water-soluble resin as a dispersant and water,
After stirring, dispersion is carried out using a dispersion means described later, and if necessary, centrifugal separation is carried out to obtain a desired dispersion liquid. Next, a sizing agent and appropriately selected additive components such as those mentioned above are added to this dispersion, and the mixture is stirred to obtain the ink used in the present invention.

When the alkali-soluble resin as described above is used as the dispersant, it is necessary to add a base to dissolve the resin. Organic amines such as ethanolamine, diethanolamine, triethanolamine, amine methyl propanol and ammonia, or inorganic bases such as potassium hydroxide and sodium hydroxide are preferably used.

Further, in the method of producing an ink containing a pigment, it is effective to carry out premixing for 30 minutes or more before stirring and dispersing the aqueous medium containing the pigment. That is, such a premixing operation is preferable because it can improve the wettability of the pigment surface and promote the adsorption on the pigment surface.

The disperser used in the dispersion treatment of the above-mentioned pigment may be any disperser generally used, and examples thereof include a ball mill, a roll mill and a sand mill. Among them, a high speed type sand mill is preferably used, and as such a thing, for example, a super mill, a sand grinder, a bead mill,
Examples thereof include agitator mill, grain mill, dyno mill, pearl mill and cobol mill (all are trade names).

When an ink containing a pigment is used in an ink jet recording method, a pigment having an optimum particle size distribution is used due to the requirement of anti-clogging property and the like, but it has a desired particle size distribution. As a method of obtaining a pigment,
Decrease the size of the crushing media of the disperser, increase the filling rate of the crushing media, lengthen the processing time, slow the discharge speed, classify with a filter or centrifuge after crushing, and these Methods such as a combination of the above methods can be mentioned.

In the present invention, when an ink containing a pigment is used, in addition to the various components described above in the ink, an anionic compound such as an anionic surfactant or an anionic polymer substance is used. Is preferably added. Especially when an anionic compound is not used as a dispersant, it is essential to add such an anionic substance. The addition amount at this time is from 0.05 to
It is 10% by weight, preferably 0.2 to 5% by weight. still,
Even when the ink containing the dye described above is used, it is preferable to add the anionic compound as described above because the effects of the present invention can be more effectively carried out.

Further, an amphoteric surfactant is added at a p value below its isoelectric point.
It is also a preferred embodiment to adjust the content to H so that it is contained in the ink. As an example of the anionic surfactant used at this time, generally used ones such as carboxylate type, sulfate type, sulfonate type and phosphate type can be preferably used. . Examples of the anionic polymer include alkali-soluble resins, specifically, sodium polyacrylate, and those obtained by copolymerizing acrylic acid with a part of the polymer.
Of course, it is not limited to these.

Next, the image forming method according to the present invention will be described. In the image forming method according to the present invention, the liquid composition as described above is applied to the image forming area on the recording medium, or the image forming area and its vicinity. And (A) in which the ink containing at least a dye containing an anionic group, or the ink containing at least an anionic compound and a pigment is ejected as a droplet from an ejection orifice onto a recording medium according to a recording signal. And the step (B) of performing. The image forming area referred to in the present invention is an area where ink dots are attached, and the vicinity of the image forming area is 1 outside the area where ink dots are attached.
It means an area about 5 dots apart.

The image forming method according to the present invention may be any method as long as the above-described liquid composition according to the present invention and the ink coexist on a recording medium or the like, and therefore, the liquid composition and the ink. It does not matter which of the above is applied to the recording medium first. Further, when the liquid composition is first adhered to the recording medium, the time from adhering the liquid composition to the recording medium to adhering the ink onto the recording medium is not particularly limited. It is preferable to deposit the ink on the recording medium at substantially the same time or within a few seconds.

The recording medium used in the above-mentioned image forming method is not particularly limited, and conventionally used so-called plain paper such as copy paper and bond paper is preferably used. Of course, a coated paper specially prepared for ink jet recording and a transparent film for OHP are also suitably used. Further, it can be suitably used for general high-quality paper and glossy paper.

As a method of applying the liquid composition onto the recording medium, for example, a method of applying the liquid composition onto the entire surface of the recording medium by a spray, a roller or the like can be considered, but more preferably, an image forming area to which the ink is attached, or It is preferable to carry out by an ink jet method capable of selectively and uniformly adhering the liquid composition only to the image forming area and the vicinity of the image forming area. At this time, various ink jet recording methods can be used, but a particularly preferable method is a method of ejecting droplets by using bubbles generated by thermal energy.

Next, a recording apparatus preferably used in the image forming method according to the present invention will be described. In the present invention, an inkjet recording method is preferably used in which a recording signal is applied to the ink of the recording head and the generated thermal energy ejects droplets. The structure of the recording head, which is the main part of such an apparatus, is shown in FIGS. 1, 2 and 3.

The head 13 is a heating head 15 having a heating resistor used for heat-sensitive recording, such as glass, ceramics, or plastic in which ink is formed in a flow path (a head is shown in the figure, but the present invention is not limited to this. Not a thing)
It is obtained by bonding and. The heating head 15 includes a protective film 16 made of silicon oxide or the like, an aluminum electrode 17-
1, 17-2, heating resistor layer 1 formed of nichrome, etc.
8, a heat storage layer 19, and a substrate 20 having a good heat dissipation property such as alumina. The ink 21 reaches the ejection orifice 22, and the pressure P forms a meniscus 23.

Here, when an electric signal is applied to the electrodes 17-1 and 17-2, the area indicated by n of the heating head 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact therewith. The meniscus is ejected by the pressure, becomes a recording droplet 24 from the orifice 22, and flies toward the recording material 25. FIG. 3 shows a schematic view of a recording head in which a large number of nozzles shown in FIG. 1 are arranged. The recording head is made by closely adhering a glass plate or the like 27 having a large number of flow paths to a heating head 28 similar to that described in FIG. 1 is a sectional view of the head 13 along the ink flow path, and FIG. 2 is a sectional view taken along the line AB of FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating the head. In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member to be a fixed end, which is in the form of a wrench lever. The blade 61 is arranged at a position adjacent to the recording area of the recording head, and is configured to move in a direction perpendicular to the moving direction of the recording head to come into contact with the ejection port surface to perform capping. Further, 63 is an ink absorber provided adjacent to the blade 61, and like the blade 61, is held in a form protruding in the moving path of the recording head. The blade 61, the cap 62, and the absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the absorber 63 remove water, dust, and the like from the ink ejection port surface.

Reference numeral 65 denotes a recording head having ejection energy generating means for ejecting ink to a recording material facing an ejection port surface having ejection ports to perform recording, and 66 denotes a recording head having the recording head 65 mounted thereon. A carriage for moving 65. The carriage 66 is movably engaged with the guide shaft 67, and a part of the carriage 66 is connected (not shown) to a belt 69 driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and its adjacent area. Reference numeral 51 is a paper feed section for inserting a recording material, and 52 is a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to the position facing the ejection port surface of the recording head,
As the recording progresses, the paper is ejected to the paper ejecting section provided with the paper ejecting roller 53.

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

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are in the same position as the above-mentioned position during wiping. As a result, the ejection opening 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 performed not only at the end of recording and at the time of ejection recovery, but also at a predetermined interval to the home position adjacent to the recording area while the recording head moves in the recording area for recording. However, the wiping is performed along with this movement.

FIG. 5 is a diagram showing an example of an ink cartridge in which ink is supplied to the head via an ink supply member, for example, a tube. Here, 40 is an ink containing portion containing the 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 this stopper 42, the ink in the ink bag 40 can be supplied to the head. Four
Reference numeral 4 is an absorber that receives waste ink. As the ink storage portion, it is preferable that the liquid contact surface with the ink is formed of polyolefin, particularly polyethylene. The ink jet recording apparatus used in the present invention is not limited to the above-described head and ink cartridge which are separate bodies, and those in which they are integrated as shown in FIG. 6 are also preferably used.

In FIG. 6, reference numeral 70 denotes a recording unit in which an ink containing portion for containing ink, for example, an ink absorber is contained, and the ink in the ink absorber has a plurality of orifices. It is configured to be ejected as an ink droplet from the portion 71. As a material for the ink absorber, for example, polyurethane can be used. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. The recording unit 70 is used instead of the recording head shown in FIG. 4, and is detachable from the carriage 66. In the recording apparatus used in the present invention, an ink jet recording apparatus that applies thermal energy to ink to eject ink droplets has been described above as an example. However, in addition to this, a piezo type ink jet recording apparatus that uses a piezoelectric element may also be used. You can use it as well.

When carrying out the recording method of the present invention, for example, a recording apparatus in which the five recording heads shown in FIG. 3 are arranged on a carriage is used. FIG. 7 shows an example thereof. Reference numerals 81, 82, 83, and 84 are recording heads for ejecting inks of yellow, magenta, cyan, and black colors, respectively. Reference numeral 85 is a head for ejecting the colorless liquid composition according to the present invention. The head is arranged in the above-mentioned recording device and ejects ink of each color according to a recording signal. Prior to that, or after ejecting each color ink, the liquid composition is applied in advance to at least a portion where each color ink adheres to the recording paper. FIG. 7 shows an example in which five recording heads are used, but the present invention is not limited to this, and as shown in FIG. 8, one recording head has inks, liquids of yellow, magenta, cyan and black colors, and liquids. It is also preferable when the composition is divided into liquid channels.
Of course, the heads may be arranged such that the order of recording the colorless liquid composition and the ink is the reverse of the order described above.

[0055]

EXAMPLES The present invention will be described more specifically by showing Examples and Comparative Examples below. In the text, "part" and "%" are based on weight unless otherwise specified. The weight average molecular weight of the dispersant for the pigment ink was measured by the GPC method using styrene polymer as a standard.

Example 1 (Preparation of Ink I) First, the following components were mixed and dissolved, and then pressure-filtered with a membrane filter having a pore size of 0.22 μm (trade name: Fluoropore filter, manufactured by Sumitomo Electric Co., Ltd.). After that, adjust the pH to 5.0 with NaOH,
A colorless liquid A1 was obtained. Components of liquid composition A -behenyltrimethylammonium chloride 1 part-lauryltrimethylammonium chloride 1 part-isopropyl alcohol 3 parts-thiodiglycol 10 parts-water 85 parts

(Preparation of Ink I) Next, the following components are mixed, and a membrane filter having a pore size of 0.22 μm (trade name: Fluoropore filter, manufactured by Sumitomo Electric Industries)
In order to obtain yellow, magenta, cyan, and black color inks Y1, M1, C1, and B1 containing a dye containing an anionic group, pressure filtration was performed. This Y1, M1,
Ink I is C1 and B1. Yellow ink Y1 C.I. I. Direct Yellow 86 2 parts-Thiodiglycol 10 parts-Acetylenol EH (Kawaken Fine Chemicals) 0.05 parts-Ion exchanged water 87.95 parts

Magenta ink M1 C.I. I. Acid Red-289 2.5 parts-Thiodiglycol 10 parts-Acetylenol EH (Kawaken Fine Chemicals) 0.05 parts-Ion-exchanged water 87.45 parts

Cyan ink C1.C. I. Acid Blue 199 4.0 parts-Thiodiglycol 10 parts-Acetylenol EH (Kawaken Fine Chemicals) 0.05 parts-Ion-exchanged water 85.95 parts

Black ink B1.C. I. Food Black-2 2.5 parts-Thiodiglycol 10 parts-Acetylenol EH 0.05 parts-Ion-exchanged water 87.45 parts

An ink set according to the present invention was constructed using the colorless liquid composition A of this example and ink I obtained as described above, and recording was carried out on PPC paper (made by Canon Inc.). The inkjet recording device used is shown in FIG.
A color image was formed using the same recording apparatus as shown in FIG. 5 and using the five recording heads shown in FIG. On this occasion,
The liquid composition A was first ejected and deposited on the recording paper, and then the ink I was deposited. The recording head used here had a recording density of 360 dpi, and the driving condition was a driving frequency of 5 kHz. The ejection volume per dot is 45 pl for yellow, magenta, and cyan inks, and for colorless liquid compositions, each head is 45 pl, and for black ink, it is 8 per dot.
A 0 pl head was used. The recording conditions are the same throughout the examples and comparative examples when the ink containing the dye described below is used. Further, the environmental conditions during the print test are unified to 25 ° C./55% RH.

Example 2 Yellow, magenta, cyan, and black color inks Y2, M2, C2, and B2 each containing a pigment and an anionic compound were obtained as described below. This Y2, M
2, C2 and B2 were used as the ink II, and the ink set of this example was constituted with the colorless liquid composition A used in the example 1. Using this ink set, recording was performed on PPC paper (manufactured by Canon). In this example, the colorless liquid composition A was first ejected and first applied on the recording paper, and then the ink II was adhered to perform printing and recording. The recording head used here had a recording density of 360 dpi, and the driving condition was a driving frequency of 5 kHz. The ejection volume per dot is 45 p for each of the yellow, magenta and cyan inks and the colorless liquid composition.
1 head was used, and for black ink, 60 pl head per dot was used. The recording conditions are the same throughout the examples when the ink containing the pigment described below is used. Further, the environmental conditions during the print test are unified to 25 ° C./55% RH.

(Preparation of Ink II) Black Ink B2 (Composition of Pigment Dispersion Liquid) -Styrene-acrylic acid-butyl acrylate copolymer 1.5 parts (acid value 116, weight average molecular weight 3,700) -monoethanol Amine 1 part ・ Diethylene glycol 5 parts ・ Ion-exchanged water 81.5 parts

The above ingredients are mixed and mixed in a water bath to 70
Warm to 0 ° C to completely dissolve the resin component. To this solution, 10 parts of carbon black (MCF88, manufactured by Mitsubishi Kasei) and 1 part of isopropyl alcohol were added, premixed for 30 minutes, and then dispersed under the following conditions.・ Disperser: Sand grinder (Igarashi Machinery) ・ Grinding media: Zirconium beads, 1mm
Diameter-Filling ratio of grinding media: 50% (volume ratio) -Grinding time: 3 hours

Further, a centrifugal separation treatment (12,000 rp)
m. For 20 minutes) to remove coarse particles to obtain a dispersion liquid. Using this dispersion, the components were mixed in the following composition ratio, and the pH was adjusted to 8 to 10 with monoethanolamine to obtain Black Ink B2. (Ink composition) -The above dispersion liquid 10 parts-Glycerin 2 parts-Diethylene glycol 15 parts-N-methylpyrrolidone 5 parts-Isopropyl alcohol 3 parts-Ion exchange water 65 parts

Yellow Ink Y2 Carbon Black (MCF88, manufactured by Mitsubishi Kasei) used in the preparation of Black Ink B2 was used as Pigment Yellow 74.
A yellow ink Y2 was prepared in the same manner as in the preparation of the black ink B2, except that the above was replaced with.

Magenta Ink M2 A magenta ink M2 was prepared in the same manner as in the preparation of the black ink B2 except that the carbon black (MCF88, manufactured by Mitsubishi Kasei) used in the preparation of the black ink B2 was replaced with Pigment Red 7. .

Cyan Ink C2 Carbon Black (MCF88, manufactured by Mitsubishi Kasei) used in the preparation of Black Ink B2 is Pigment Blue 15:
A cyan ink C2 was prepared in the same manner as in the preparation of the black ink B2 except that it was replaced with 3.

Example 3 A colorless liquid composition B of the present example, which was prepared in the same manner as the liquid composition A and consisted of the following components, and an ink I containing the same dye as that used in Example 1 as a coloring material. Is used to configure an ink set according to the present invention, and under the same conditions as in Example 1,
Recording was performed on PPC paper (manufactured by Canon). Also in this example, the colorless liquid composition B was first ejected and first adhered to the recording paper, and then the ink I was adhered to perform the printing and recording. Components of Liquid Composition B Stearylbenzyldimethylammonium chloride 1 part Cetyltrimethylammonium chloride 1 part n-Butyl alcohol 2 parts Isopropyl alcohol 1 part Thiodiglycol 10 parts Deionized water 85 parts

Example 4 The ink set of this example was composed of the colorless liquid composition B used in Example 3 and the ink II containing the pigment used in Example 2, and the ink set of this example was used. Recording was performed on PPC paper (manufactured by Canon Inc.) under the same conditions as in Example 1. In this example, the colorless liquid composition B was first ejected and first applied on the recording paper, and then the ink II was applied to perform printing and recording.

Example 5 A colorless liquid composition C of this example, which was prepared in the same manner as the liquid composition A and consisted of the following components, and an ink I using the same dye as that used in Example 1 as a coloring material. Is used to configure an ink set according to the present invention, and under the same conditions as in Example 1,
Recording was performed on PPC paper (manufactured by Canon). Also in this example, the colorless liquid composition C was first ejected and first applied on the recording paper, and then the ink I was applied to perform the printing and recording. Components of Liquid Composition C- Distearyldimethylammonium chloride 1 part-Laurylbenzyldimethylammonium chloride 1 part-Isobutyl alcohol 2 parts-Ethyl alcohol 2 parts-Thiodiglycol 10 parts-Ion-exchanged water 84 parts

Example 6 The ink set of this example was composed of the colorless liquid composition C used in Example 5 and the ink II containing the pigment used in Example 2, and the ink set of this example was used. Recording was performed on PPC paper (manufactured by Canon Inc.) under the same conditions as in Example 1. In this example, the colorless liquid composition B was first ejected and first applied on the recording paper, and then the ink II was applied to perform printing and recording.

Examples 7-12 Using the same liquid composition and ink combinations used in Examples 1-6, the ink was applied to the recording paper and then the colorless liquid composition was post-applied and applied. The same recording evaluation as in Example 1 was carried out except that.

Comparative Example 1 The same printing and evaluation as in Example 1 were carried out except that the colorless liquid composition used in Example 1 was not used.

[0075]

[Evaluation] The recorded images obtained in Examples 1 to 16 and Comparative Example 1 were evaluated by the following evaluation methods and evaluation criteria. 1. Image density A solid image was formed using a colorless liquid composition and black ink, and the reflection density after standing for 12 hours was measured by a reflection densitometer Macbeth RD915 (manufactured by Macbeth). The evaluation criteria are as follows. ⊚: Reflection density is 1.30 or more O: Reflection density is 1.25 or more and less than 1.30 Δ: Reflection density is 1.15 or more and less than 1.25 ×; Reflection density is less than 1.15

2. Fixability After forming a red solid image using a colorless liquid composition and yellow and magenta ink, another white paper is superposed on the recorded image by its own weight, and the recorded image is transferred to the back side of the paper. The time until disappearance of background stains was measured by setting the time at the end of recording as time zero, and the result was used as a standard for fixing property. The evaluation criteria are as follows. ⊚: Fixability is less than 20 seconds ◯: Fixability is 20 seconds or more and less than 30 seconds Δ: Fixability is 30 seconds or more and less than 40 seconds ×; Fixability is 40 seconds or more

3. Character Quality Black alphanumeric characters were printed using a colorless liquid composition and black ink and evaluated visually. When the feathering was hardly noticeable, it was marked with ⊚, when the feathering was slightly conspicuous but there was no practical problem, it was marked with ◯, and when it was lower than that, it was marked with x.

4. Bleeding Canon Color Bubble Jet Printer BJC-8
In the same printing mode as 20J printing mode A (2Pass, one-way printing), a colorless liquid composition and solid portions of yellow, magenta, cyan, and black inks are printed adjacent to each other, and at the boundary portion of each color. The degree of bleeding was visually observed. The case where bleeding rarely occurred was marked with ⊚, the case where bleeding occurred slightly but there was a level where there was practically no problem was marked with ○, and other levels were marked with x.

5. Water resistance A solid image of each color ink of yellow, magenta, cyan, and black was printed, left for 1 hour, and then immersed in tap water at a water temperature of 20 ° C for 5 minutes. Then, remove it from the water, lightly press the filter paper to remove the water on the surface of the recorded image,
It was air dried as it was. Image density (OD value) before water resistance test
And the OD value after the water resistance test, the remaining OD after the water resistance test
The rate was expressed as a percentage and used as a measure of water resistance. yellow,
Among magenta, cyan and black, the one having the lowest water resistance was taken as the water resistance evaluation result. The water resistance evaluation criteria are as follows. ⊚: Residual OD ratio of 80% or more ◯: Residual OD ratio of 70% or more and less than 80% ×: Residual OD ratio of less than 70% The area where the colorless liquid composition adheres to the recording medium in the above evaluation Is the same area as the ink image forming area,
The printing duty is 100% for both the colorless liquid composition and the ink. Further, the printing direction is unidirectional.

Table 1 shows the evaluation results of the images obtained in Examples 1 to 12 and Comparative Example 1 with respect to the above evaluation items. As is clear from Table 1, in Examples, images having good fixability, character quality, image density, bleeding and water resistance were obtained, whereas in Comparative Example 1, bleeding occurred and images with poor character quality were obtained. However, the water resistance of the image was poor.

Table 1 Evaluation results

Example 13 Colorless liquid composition used in Example 1 and 3 of yellow, magenta and cyan in Ink I used in Example 1
A solid image was recorded at 100% duty using colors to form a so-called process black. All printed conditions were the same as in Example 1. Image density at this time,
The evaluation results of the fixability, character quality, water resistance, and bleeding at the boundary between the process black and other colors were all good, confirming the effects of the present invention.

[0083]

As described above, according to the present invention, particularly in the case of performing color ink jet recording on plain paper, it is possible to obtain a high print quality and a sufficient image density while having a high-speed fixing property. Moreover, the uniformity of the solid image is also high, and a high-definition image with good color reproducibility can be obtained with bridging.
Moreover, an excellent ink jet recorded image can be provided in which the excellent image as described above completely satisfies the water resistance. Furthermore,
According to the present invention, since it is not necessary to use a cationic polymer substance having a large molecular weight as in the prior art, it is possible to reduce the viscosity of the liquid, which is advantageous in the ejection characteristics when performing inkjet recording. In addition, since it is not necessary to use a polyvalent metal salt as in the case of the prior art, kogation, which is a peculiar problem when using a thermal inkjet recording head, is effectively prevented, resulting in high reliability. Stable ink jet recording is performed with.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a head portion of an inkjet recording apparatus.

FIG. 2 is a cross-sectional view of a head portion of an inkjet recording device.

FIG. 3 is an external perspective view of a head portion of the inkjet recording apparatus.

FIG. 4 is a perspective view showing an example of an inkjet recording apparatus.

FIG. 5 is a vertical sectional view of an ink cartridge.

FIG. 6 is a perspective view of a recording unit.

FIG. 7 is a perspective view showing a recording unit in which a plurality of recording heads used in an embodiment of the present invention are arranged.

FIG. 8 is a perspective view of another recording head used in the present invention.

FIG. 9 is a conceptual diagram showing an image method according to the present invention.

[Explanation of symbols]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // C09D 11/00 PSZ B41J 3/04 101 A

Claims (12)

[Claims] 1. A liquid composition containing at least a cationic substance, wherein at least one selected from cationic compounds represented by the following general formulas (I) to (III) is water-soluble by using a water-soluble organic solvent. A liquid composition characterized in that it is solubilized and contained in and also contains a water-soluble cationic surfactant. [In the above general formula, R represents an alkyl group having 18 or more carbon atoms, and X represents Cl or Br. ] 2. The liquid composition according to claim 1, wherein the water-soluble organic solvent is at least one monohydric alcohol selected from the group consisting of ethanol, isopropyl alcohol, n-butyl alcohol and isobutyl alcohol. 3. The liquid composition according to claim 1, which is used for image formation. 4. A liquid composition according to claim 1, which comprises at least one ink selected from the group of inks of each color of yellow, magenta, cyan, black, red, blue and green, and each ink contains An ink set comprising a water-soluble dye containing at least an anionic group or containing at least an anionic compound and a pigment. 5. The ink set according to claim 4, wherein three color inks of yellow, magenta and cyan are used. 6. The ink set according to claim 4, wherein four color inks of yellow, magenta, cyan and black are used. 7. The ink set according to claim 4, wherein the surface tension of the liquid composition is lower than the surface tension of each color ink. 8. A step (A) of adhering the liquid composition according to claim 1 or 3 to an image forming area or an image forming area on a recording medium and its vicinity, and a water solution containing at least an anionic group. Ink containing a functional dye, and / or
Alternatively, the method may include a step (B) of ejecting an ink containing at least an anionic compound and a pigment as droplets from a discharge orifice onto a recording medium according to a recording signal. 9. The image forming method according to claim 8, wherein the ink ejection in step (B) is performed by an inkjet recording method. 10. The method for depositing a liquid composition on a recording medium in step (A) by an inkjet method.
The image forming method described in 1 .. 11. The image forming method according to claim 8, wherein the step (A) is performed prior to the step (B). 12. The image forming method according to claim 8, wherein step (A) is performed after step (B).