JPH0880664A - Liquid composition, ink set and image forming method and apparatus using them - Google Patents

Abstract

PURPOSE: To improve a printing grade while imparting good fixing properties to plain paper, to obtain sufficient image density and to enhance the uniformity of a solid image by using a liquid compsn. containing a cationic substance and bishydroxyethylsulfone. CONSTITUTION: A liquid compsn. contains at least one cationic substance and further contains bishydroxyethylsulfone. When the liquid compsn. is mixed with ink at a position where it penetrates into recording paper, for example, in a case used along with ink containing a dye having an anionic group as a colorant, the low mol.wt. component of the cationic substance and anionic compd. generate association by ionic mutual action and the dye is instantaneously flocculated to be separated from a soln. layer and subsequently adsorbed by the high mol.wt. component contained in the liquid compsn. and the size of the floc containing the dye becomes large to become hard to enter the gaps between fibers of recording paper and only the liquid part penetrates into the recording paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reducing a so-called color bleeding (phenomenon) that occurs when a color image is formed on plain paper and obtaining an image having water resistance, and more particularly, an ink jet system. The present invention relates to a liquid composition optimally used for image formation using a recording method, an ink set in which the liquid composition is combined, and an image forming method and apparatus using these.

[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, JP-A-63-299971 discloses an ink containing an anionic dye after a liquid containing an organic compound having two or more cationic groups per molecule is attached to 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 the water resistance of the image are improved by precipitating the dye itself, the effect of suppressing the 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 six 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. Furthermore, the following points are also important problems when performing thermal inkjet recording. To improve the ejection durability of a recording head of a liquid composition different from the ink provided for improving the image.

[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 one cationic substance, further containing bishydroxyethyl sulfone, an ink set combining the liquid composition, And an image forming method and an image forming apparatus using these.

[0009]

The function of the liquid composition according to the present invention will be described with reference to the drawings. The liquid composition containing a cationic substance according to the present invention is mixed with an ink at a recording paper or at a position where it penetrates into a recording paper when used with an ink containing a dye containing an anionic group as a coloring material. Then, as shown in FIG. 9C, as the first step of the reaction,
The low molecular weight component of the cationic substance contained in the liquid composition and the anionic compound in the ink associate with each other by ionic interaction, and the dye instantaneously aggregates and separates from the solution phase. Cause

Next, in the second step of the reaction, the dye formed by the association between the anionic compound and the low molecular weight cationic substance is adsorbed by the high molecular weight component contained in the liquid composition. The size of the agglomerates including is further increased (shown in FIG. 9D), and it becomes difficult for the agglomerates to enter the gaps between fibers of the recording paper. As a result, solid-liquid separation occurs, and only the liquid portion seeps into the recording paper (see FIG. 9 (e)).
It is possible to achieve both improved print quality and improved fixability. 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 in the liquid composition, which is generated by the mechanism as described above, increases, and As it does not move with movement, like the conventional full-color image formation described above,
Even if adjacent dots are formed of different color inks, 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. or,
It also has the effect of improving the light fastness of the image formed by the polymer shielding effect.

Further, when the bishydroxyethyl sulfone used in the liquid composition of the present invention is used in a thermal ink jet recording system in which a recording signal is applied to the recording ink of a recording head and droplets are discharged by the generated thermal energy. Since it has the effect of lowering the foaming temperature at the time of discharging the liquid composition, when the liquid composition contains an organic compound, it is necessary to prevent kogation of the organic compound on the heating head. As a result, the ejection durability of the heating head can be improved.

[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 characterized by further containing bishydroxyethyl sulfone. In a more preferred embodiment, the liquid composition is one in which the cationic substance has at least a peak in the molecular weight region shown below and / or in the molecular weight distribution measured by GPC. Among these, particularly preferred is an embodiment using at least two or more kinds of cationic substances each having a peak of molecular weight distribution in a different molecular weight region described in and.

A high molecular weight cationic substance having a molecular weight distribution peak measured by GPC in a region of a molecular weight of 1,500 or more and 10,000 or less is used. The peak of the molecular weight distribution measured by GPC has a molecular weight of 1,000 or less, more preferably 100 to 100.
A low molecular weight cationic material present in the 700 region is used. The molecular weight described in the present invention means the molecular weight in terms of polyethylene oxide unless otherwise specified.

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

The constituent components of the liquid composition of the present invention will be described below. The content of bishydroxyethyl sulfone, which is an essential component of the liquid composition of the present invention, in the liquid composition is not particularly limited as long as it is a range that can achieve the intended purpose of the present invention. , 5-40% by weight
It is preferable that the content is included to some extent. When bishydroxyethyl sulfone is added to the liquid composition, the liquid composition is ejected by a thermal ink jet recording method in which a recording signal is applied to recording ink of a recording head to eject droplets by thermal energy generated. In addition, since it is possible to lower the foaming temperature at the time of discharging the liquid composition, it is possible to effectively prevent kogation of these organic compounds on the heating head that occurs when the liquid composition contains an organic compound. I can. As a result, the ejection durability of the heating head can be improved and stable ejection can be achieved.

The liquid composition of the present invention is required to contain at least a cationic substance in addition to the above-mentioned bishydroxyethyl sulfone. The cationic substance used in this case may be any as long as it can achieve the intended purpose of the present invention, but preferably,
It is preferable to use a cationic substance having a peak of the molecular weight distribution in the molecular weight range described above and / or. More preferably, it is preferable to contain at least two kinds of cationic substances each having a peak of the molecular weight distribution in these different molecular weight regions.

The action and effect of the liquid composition of the present invention are as described above, but since the liquid composition contains a cationic substance, when mixed with the ink on the recording medium,
First, for example, a low molecular weight cationic substance having a peak of molecular weight distribution in a region having a molecular weight of 1,000 or less as shown above, more preferably in a region having a molecular weight of 100 to 700, and a coloring material are contained in the ink. First, the existing anionic compound forms an aggregate by ionic interaction. The formation reaction rate of this aggregate needs to be extremely high.

Here, the above-mentioned molecular weight of 100
The low molecular weight cationic substance having a peak of the molecular weight distribution in the region of 0 or less, more preferably in the region of 100 to 700 is specifically described below. For example, primary, secondary and tertiary amine salt type compounds, specifically, hydrochlorides such as laurylamine, coconut amine, stearylamine and rosinamine,
Acetate, etc .; quaternary ammonium salt type compound, specifically lauryl trimethyl ammonium chloride, lauryl dimethyl benzyl ammonium chloride, benzyl tributyl ammonium chloride, benzalkonium chloride, etc .; Pyridinium salt type compound, specifically cetyl Pyridinium chloride, cetylpyridinium bromide, etc .; imidazoline type cationic compounds, specifically 2
-Heptadecenyl-hydroxyethyl imidazoline and the like;
Ethylene oxide adducts of higher alkyl amines, specifically dihydroxyethyl stearyl amine and the like are preferable.

Further, in the present invention, other p
Amphoteric surfactants that exhibit a cationic property in the H region are also preferably used as the low molecular weight cationic substance.
Specifically, for example, an amino acid type amphoteric surfactant; RN
H-CH ₂ -CH ₂ -COOH type compounds; betaine type compounds, specifically, stearyl dimethyl betaine, other carboxylic acid salt type amphoteric surfactants such as lauryl betaine, sulfuric ester type, sulfonic acid Mold,
Examples include amphoteric surfactants such as phosphoric acid ester type. 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 take any method of adjusting the pH so that the pH is below the isoelectric point.

In the above, examples of low molecular weight cationic substances have been given as examples of the cationic substance, but it goes without saying that the cationic substances usable in the present invention are not necessarily limited to these. For example, as another example of the cationic substance that can be used in the present invention, a monomer or oligomer of a high molecular weight cationic substance described below may be used.

Next, regarding the action and effect of the high molecular weight cationic substance having the peak of the above-mentioned molecular weight distribution in the range of 1,500 or more and 10,000 or less in the present invention, the liquid composition is as described above. As a second step of the reaction between the substance and the ink, a complex with a low molecular component of the cationic substance as shown in the above-mentioned dye having an anionic group is adsorbed in the molecule, and the dye formed by the association is adsorbed. Achieving both print quality and fixability by allowing only the liquid portion that has undergone solid-liquid separation to permeate into the recording paper by making the size of the agglomerates larger to prevent it from entering the gaps between the fibers of the recording paper. Especially. The above effects are exhibited to some extent even without the use of the low molecular weight cationic substance.

Further, in the present invention, a nonionic polymer may be further contained. It is preferable to use the nonionic polymer having the above-mentioned molecular weight as well, and this also has the same action and effect as the above-mentioned cationic polymer substance. Specific examples of the high molecular weight nonionic substance used at this time include, but are not limited to, polyvinyl alcohol, polyvinylpyrrolidone, and water-soluble cellulose.
Specific examples of the cationic substance include, but are not limited to, polyalkylamine hydrochloride, polyaminesulfone hydrochloride, polyvinylamine hydrochloride, chitosan acetate and the like. .

Another specific example of the high molecular weight cationic substance used in the present invention may be a compound obtained by cationizing a part of the nonionic polymer substance. Specific examples include a copolymer of vinylpyrrolidone and a quaternary salt of aminoalkyl alkylate and a copolymer of a quaternary salt of acrylic amide and aminomethyl acrylic amide, but of course, these compounds It goes without saying that it is not limited to. Further, the above-mentioned high molecular weight substance and high molecular weight cationic substance are satisfactory as long as they are water-soluble, but they may be dispersions such as latex and emulsion.

The position of the peak of the molecular weight distribution of the high molecular weight cationic substance as described above is 1,500 or more.
A compound in the range of 10,000 or less is preferable for carrying out the present invention, but more preferably, a compound having a peak on the lower molecular side in the range of 1,500 to 7,000 is used. Are more preferable in that the color developability of a coloring material such as a dye is not deteriorated. Further, when the liquid composition is applied to a recording medium using an inkjet recording head, the solution viscosity can be kept low even if the content of the cationic substance having a peak of molecular weight distribution on the lower molecular weight side is increased. There is also an advantage that the ejection characteristics of the liquid composition are kept good.

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. Further, in the present invention, when two kinds of cationic substances having peak positions of the above-mentioned molecular weight distributions in the respective regions different from each other are contained in the liquid composition of the present invention, The mixing ratio of the low molecular weight cationic substance and the high molecular weight cationic substance in the composition is in the range of 10: 1 to 1:10, preferably 5: 1 to 1: 5 by weight. If this ratio exceeds 10: 1, it is difficult to obtain sufficient water resistance, and conversely, if it is 1:10 or less, bleeding is not sufficiently suppressed, and at the same time, the sharpness of the edge of the dot tends to decrease.

Regarding the molecular weight distribution of the cationic compound used in the present invention, GPC measurement may be carried out individually in advance, or after measuring the molecular weight distribution of the liquid composition itself, it has at least an anionic group. A sufficient amount of ink containing a dye and the liquid composition were mixed and stirred in a beaker, and after removing the precipitate, GPC measurement was performed again. Before mixing the ink and after mixing the ink and removing the precipitate, It may be obtained by comparing the measurement results of GPC and from the molecular weight distribution of the components that are precipitated by the dye in the ink and removed from the system.

Next, other components constituting the liquid composition of the present invention will be specifically described. The liquid composition of the present invention, in addition to the cationic substances described above and the like, usually water,
It consists of a water-soluble organic solvent and other appropriate additives.
Examples of the water-soluble organic solvent used at this time include amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and ethylene. Alkylene glycols such as glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol, ethylene glycol methyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether. Lower alkyl ethers of polyhydric alcohols such as ethanol, isopropyl alcohol, n
In addition to monohydric alcohols such as -butyl alcohol and isobutyl alcohol, glycerin, N-methyl-2-pyrrolidone, 1,3-dimethyl-imidazolidinone, triethanolamine, sulfolane and dimethylsulfoxide are preferably used. . The content of the water-soluble organic solvent is not particularly limited, but is 5 to 6 of the total weight of the liquid composition.
A suitable range is 0% by weight, more preferably 5 to 40% by weight.

Further, the liquid composition of the present invention further comprises:
If necessary, additives such as a viscosity adjusting agent, a pH adjusting agent, a preservative, various surfactants, an antioxidant and an evaporation accelerator 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 of the present invention is more preferably colorless, but may be a light color composition within a range that does not change the color tone of each color ink when mixed with ink on a recording medium or the like. Further, the preferable range of various physical properties of the liquid composition as described above is 25
Around 3 ° C, the pH is adjusted to 3 to 12, preferably 3 to 8, more preferably 3 to 5, and the surface tension is 10 to 60 dyn / c.
m, more preferably 10 to 40 dyn / cm, and have a viscosity of 1 to 30 cps. It is what As will be described later, the surface tension of the liquid composition of 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 of the present invention will be described. The ink used in the present invention is
When a water-soluble dye containing an anionic group is used as the coloring material, or when a pigment is used as the coloring material, a combination of anionic compounds is used. 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 having an anionic group used in the present invention includes a color index (COLOU).
R INDEX), water-soluble acid dyes,
There is no particular limitation as long as it is a direct dye or a reactive dye. 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 coloring material as described above,
The water-soluble organic solvent used in the liquid composition of 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 of the present invention, because it may be effective in carrying out the image forming method of the present invention.
This is because if the surface tensions of the two are adjusted in this way, for example, in the printing process,
It is thought that this is because the effect of making the wettability of the ink ejected later on the recording medium uniform can be achieved.
The details are not clear.

When a pigment is used as a 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).

As the water-soluble organic solvent used by mixing with water, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, etc. 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. Similarly to the above, when an ink containing a pigment is used, it is preferable that the surface tension of the ink is larger than the surface tension of the liquid composition of the present invention. It is preferable to adjust the surface tension of the ink in such a manner.

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 above-mentioned alkali-soluble resin is used as the dispersant, it is necessary to add a base in order 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 pigment-containing aqueous medium. That is, such premixing operation is preferable because it improves wettability of the pigment surface and promotes adsorption of the dispersant 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 because of a demand for clogging resistance 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. It is also a preferred embodiment to adjust the pH of the amphoteric surfactant to be equal to or higher than its isoelectric point and to contain the amphoteric surfactant. 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. . Further, as an example of the anionic polymer,
Examples thereof include alkali-soluble resins, specifically, sodium polyacrylate, a polymer obtained by copolymerizing acrylic acid with a part of the polymer, etc., but are not limited thereto.

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

The image forming method according to the present invention may be any method as long as the above-mentioned liquid composition and ink according to the present invention coexist on a recording medium or the like. Therefore, the liquid composition and 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 or 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 to 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 of 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 has a heating head 15 having a glass, ceramic, or plastic plate having a groove 14 through which ink passes and a heating resistor used for thermal recording (thin film head is shown in the figure, but the present invention is not limited to this. It is obtained by adhering and. The heating head 15 includes a protective film 16 formed of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 formed of nichrome or the like, a heat storage layer 19, and a substrate 20 having good heat dissipation such as alumina. Has become The recording ink 21 reaches the ejection orifice 22, and the pressure P forms a meniscus 23.

Here, the aluminum electrodes 17-1 and 1
When an electric signal is applied to 7-2, the area indicated by n of the heating head 15 rapidly generates heat, and the ink 2 in contact therewith
Bubbles are generated at 1, and the pressure causes the meniscus 23 to project, forming ink droplets 24 from the ejection orifice 22 and flying 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 by the recording head 65, and in the case of this example,
The recording head 65 is held in a protruding form in the moving path. Reference numeral 62 denotes a cap of the ejection 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 caps. Is provided. Further, 63 is an ink absorber provided adjacent to the blade 61, and like the blade 61, is held in a form protruding in the movement path of the recording head 65. The blade 61, the cap 62, and the ink absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the ink 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 the ejection port surface where the ejection ports are arranged for recording, and 66 denotes a recording head 65 mounted and moved. It is a carriage for performing. The carriage 66 is slidably 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. 51 is a feeding section for inserting a recording material,
52 is a feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection port surface of the recording head 65, and is discharged to a discharge portion provided with a discharge roller 53 as the recording progresses.

In the above structure, when the recording head 65 returns to the home position after recording is completed, the cap 62 of the ejection recovery unit 64 is retracted from the movement path of the recording head 65, but the blade 61 is projected into the movement path. 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 wiping position. As a result, the ejection opening surface of the recording head 65 is wiped even during this movement. The movement of the recording head 65 to the home position is performed not only at the end of recording or at the time of ejection recovery but also at the home position adjacent to the recording area at a predetermined interval while the recording head 65 moves in the recording area for recording. And the wiping is performed in accordance with this movement.

FIG. 5 is a diagram showing an example of an ink cartridge 45 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.
An ink absorber 44 receives the waste ink. As the ink containing portion, the liquid contact surface with the ink is polyolefin,
Particularly, those formed of polyethylene are preferable. 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 in place 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 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 a colorless liquid composition. The head is arranged in the above-mentioned recording device and ejects ink of each color according to a recording signal. or,
Prior to this, the colorless liquid composition is applied in advance to at least the portion where the ink of each color is applied 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 can be used for yellow, magenta, cyan and black, and a colorless liquid composition. It is also preferable to perform the process in separate liquid flow paths.
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.

[0060]

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 peak of the molecular weight distribution of the cationic substance was measured by the GPC method using a polyethylene oxide standard. Further, the weight average molecular weight of the dispersant of the pigment ink was measured by the GCP method using styrene polymer as a standard, and the average particle diameter of the dispersant was measured by the dynamic light scattering method.

Example 1 First, the following components were mixed and dissolved, and then pressure-filtered with a membrane filter (trade name: Fluoropore filter, manufactured by Sumitomo Electric Industries) having a pore size of 0.22 μm, and then N
The pH was adjusted to 4.8 with aOH to obtain the liquid composition A of this example. Components of liquid composition A -bishydroxyethyl sulfone 7.5 parts-polyallylamine hydrochloride (PAA-HCI-3L, Nitto Boseki, peak of molecular weight distribution = 10,000) 1.5 parts-thiodiglycol 5 parts・ Water 86.0 copies

(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,
Recording liquid I is C1 and B1.

Yellow ink Y1 · C. I. Direct Yellow 142 2 parts-Thiodiglycol 10 parts-Acetylenol EH 0.05 parts-Water 87.95 parts

Magenta ink M1 · C. I. Acid Red 289 2.5 parts-Thiodiglycol 10 parts-Acetylenol EH 0.05 parts-Water 87.45 parts

Cyan ink C1.C. I. Acid Blue 9 2.5 parts-Thiodiglycol 10 parts-Acetylenol EH 0.05 parts-Water 87.45 parts

Black ink B1.C. I. Food Black 2 4.0 parts-Thiodiglycol 10 parts-Acetylenol EH 0.05 parts-Water 85.95 parts

An ink set according to the present invention was constructed using the liquid composition A of this example and the ink I obtained as described above, and recording was carried out on PPC paper (manufactured by Canon Inc.).
As the inkjet recording apparatus used, a recording apparatus similar to that shown in FIG. 4 was used, and a color image was formed using the five recording heads shown in FIG. 7. At this time, 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 is 36
The recording density was 0 dpi, and the driving condition was a driving frequency of 5 kHz. The ejection volume per dot was 45 pl for each of the yellow, magenta and cyan inks, the liquid composition, and 80 pl for each black ink. The recording conditions are the same throughout the examples and comparative examples when the ink containing the dye described below is used. Also, the environmental condition during the print test is 25 ° C.
/ 55% RH is standardized.

Example 2 A liquid composition B of the present example comprising the following components prepared in the same manner as the liquid composition A, and an ink I containing the same dye as that used in Example 1 as a coloring material were used. The ink set according to the present invention is configured according to the same conditions as those of the first embodiment.
Recording was performed on paper (made by Canon). Also in this example, the liquid composition B was first ejected and first applied on the recording paper, and then the ink I was adhered to perform print recording.

Components of Liquid Composition B : Bishydroxyethylsulfone 10 parts Polyamine sulfone hydrochloride (PAS-A-5: Nitto Boseki, peak of molecular weight distribution = 3,500) 2.5 parts benzalkonium chloride (Cation G-50: Sanyo Kasei, molecular weight: 354) 2 parts-thiodiglycol 5 parts-water 80.5 parts

Example 3 A liquid composition C of this example, which was prepared in the same manner as the liquid composition A and comprised of the following components, and an ink I containing the same dye as that used in Example 1 as a coloring material were used. The ink set according to the present invention is configured according to the same conditions as those of the first embodiment.
Recording was performed on paper (made by Canon). Also in this example, the liquid composition C was first ejected and first applied on the recording paper, and then the ink I was applied to perform print recording.

Components of liquid composition C : 15 parts of bishydroxyethyl sulfone; polyvinyl alcohol (manufactured by Aldrich: peak of molecular weight distribution = 9,000 to 10,000) 1.0 part; cetyltrimethylammonium chloride (Levon TM- 16: Sanyo Kasei, molecular weight: 354) 2 parts-diethylene diglycol 5 parts-water 77.0 parts

Example 4 An ink set according to the present invention was constructed by using a liquid composition D of this example consisting of the following components and an ink I containing the same dye as that used in Example 1 as a coloring material. Recording was performed on PPC paper (manufactured by Canon Inc.) under the same conditions as in Example 1. In this example as well, the liquid composition D was first ejected and first applied on the recording paper, and then the ink I was applied to perform print recording.

Components of liquid composition D : 15 parts of bishydroxyethyl sulfone-polyvinylpyrrolidone (PVP-K15, manufactured by International Specialty Chemicals, molecular weight distribution peak = 8,000) 3.0 parts-benzyltri-n-butylammonium chloride (Molecular weight: 311) 3 parts-Thiodiglycol 5 parts-Water 74.0 parts

Example 5 As described below, yellow, magenta, cyan, and black color inks Y2, M2, C2, and B2 each containing a pigment and an anionic compound were obtained. This Y2, M
Ink II was used as Nos. 2, C2 and B2, and the ink set of this example was configured with the liquid composition A used in Example 1. Using this ink set, recording was performed on PPC paper (manufactured by Canon). In this embodiment, the liquid composition A is first ejected and first applied on the recording paper, and then the ink II is used.
Was attached to print and record. 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 the yellow, magenta and cyan inks, the liquid composition A, and 60 pl for each black ink.
I used the head. The recording conditions are the same throughout the examples when the ink containing the pigment described below is used. Also, the environmental condition during the print test is 25 ° C.
/ 55% RH is standardized.

(Preparation of Ink II) Black Ink B2 Anionic Polymer P-1 (styrene-methacrylic acid-ethyl acrylate, acid value 400, weight average molecular weight 6,0)
00, an aqueous solution with a solid content of 20%, a neutralizing agent: potassium hydroxide) was used as a dispersant, and the following materials were charged into a batch type vertical sand mill (made by AIMEX) and 1 mm diameter glass beads were filled as a medium. The dispersion treatment was performed for 3 hours while cooling with water. The viscosity after dispersion was 9 cps and the pH was 10.0. This dispersion was centrifuged to remove coarse particles, to prepare a carbon black dispersion having a weight average particle diameter of 100 nm.

(Composition of carbon black dispersion) -P-1 aqueous solution (solid content 20%) 40 parts-Carbon black Mogul L (manufactured by Cablack) 24 parts-Glycerin 15 parts-Ethylene glycol monobutyl ether 0.5 parts- Isopropyl alcohol 3 parts / water 135 parts Next, the dispersion obtained above was sufficiently stirred to obtain an inkjet black ink B2 containing a pigment. The solid content of the final preparation was about 10%.

Yellow ink Y2 anionic polymer P-4 (styrene-acrylic acid-ethyl acrylate, acid value 140, weight average molecular weight 9,50)
0, an aqueous solution having a solid content of 20%, a neutralizing agent: monoethanolamine) as a dispersant, and the following materials were used:
The dispersion treatment was performed in the same manner as in the production of the black ink B2 to produce a yellow color dispersion having a weight average particle diameter of 103 nm.

Composition of Yellow Dispersion P-4 aqueous solution (solid content 20%) 35 parts C.I. I. Pigment Yellow 74 24 parts Triethylene glycol 15 parts 2,3-Butanediol 2.0 parts Isopropyl alcohol 4 parts Water 135 parts

The yellow dispersion obtained above was thoroughly stirred to obtain a yellow ink Y2 for ink jet containing a pigment. The solid content of the final preparation was about 10%.

Cyan Ink C2 Using the anionic polymer P-1 used in the preparation of the black ink B2 as a dispersant, and using the following materials, the same dispersion treatment as in the case of the carbon black dispersion described above. Then, a cyan color dispersion having a weight average particle diameter of 120 nm was produced.

(Composition of cyan color dispersion) P-1 aqueous solution (solid content 20%) 30 parts C.I. I. Pigment Blue 15: 3 (Fastgen Blue FGF, Dainippon Ink and Chemicals) 24 parts ・ Glycerin 15 parts ・ Diethylene glycol monobutyl ether 0.5 parts ・ Isopropyl alcohol 3 parts ・ Water 135 parts

The cyan color dispersion obtained above was sufficiently stirred to obtain a cyan ink C2 for ink jet containing a pigment. The solid content of the final preparation was about 9.6%.

Using the anionic polymer P-1 used in the preparation of the magenta ink M2 black ink B2 as a dispersant and using the materials shown below, the same dispersion treatment as in the case of the carbon black dispersion described above. Then, a magenta color dispersion having a weight average particle diameter of 115 nm was produced. (Composition of magenta color dispersion) P-1 aqueous solution (solid content 20%) 20 parts C.I. I. Pigment Red 122 (Dainippon Ink and Chemicals) 24 parts ・ Glycerin 15 parts ・ Isopropyl alcohol 3 parts ・ Water 135 parts

The magenta color dispersion obtained above was sufficiently stirred to obtain a magenta ink M2 for ink jet containing a pigment. The solids content of the final preparation is about 9.2.
%Met.

Example 6 Ink II containing the pigment used in Example 5,
The liquid composition B used in Example 2 was used to form the ink set of this example, and this was used to perform recording on PPC paper (manufactured by Canon Inc.) under the same conditions as in Example 5. In this example, the 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 7 Ink II containing the pigment used in Example 5,
The ink composition of this example was constructed with the liquid composition C used in Example 3, and recording was carried out on PPC paper (manufactured by Canon Inc.) under the same conditions as in Example 5 using this. In this example, the liquid composition C was first ejected to be first deposited on the recording paper, and then the ink II was deposited for printing and recording.

Example 8 Ink II containing the pigment used in Example 5,
An ink set of this example was constructed with the liquid composition D used in Example 4, and recording was carried out on PPC paper (manufactured by Canon Inc.) under the same conditions as in Example 5 using this ink set. In this example, the liquid composition D was first ejected and first applied on the recording paper, and then the ink II was applied to perform printing and recording.

Examples 9 to 16 The ink set of this example was prepared by using the combinations of the ink and liquid composition used in Examples 1 to 8, respectively.
First, printing and recording were carried out in the same manner as in Example 1 or Example 5 except that the ink was attached to the recording paper and the liquid composition was post-printed.

The combinations of the liquid compositions and the inks used in Examples 1 to 16 and which was recorded first are summarized in Table 1 below. Table 1 Contents of Examples 1 to 16

[Evaluation] The recorded images obtained in Examples 1 to 16 were evaluated by the following evaluation methods and evaluation criteria.

1. Image density A solid image is formed using a liquid composition and black ink, and the reflection density after standing for 12 hours is measured by a reflection densitometer Macbeth R.
It was measured with D915 (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 the liquid composition and the yellow ink and magenta ink, another white paper is superposed on the recorded image by its own weight, and the transfer of the image recorded on the back side of the paper disappears. The time until the occurrence of scumming was measured with the time at the end of recording as zero as a reference, and was used as a measure of 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 the liquid composition and black ink and evaluated visually. As the evaluation criteria, ⊚ was given when the feathering was hardly noticeable, ◯ was given when the feathering was slightly noticeable but there was no practical problem, and x was given when the feathering was lower.

4. Bleeding Canon Color Bubble Jet Printer BJC-8
In the same printing mode as the 20J printing mode E (1 Pass, one-way printing), the liquid composition and the solid portions of the yellow, magenta, cyan, and black inks are printed adjacent to each other, and the bleeding at the boundary of each color is performed. The degree was visually observed. As the evaluation criteria, ⊚ indicates that bleeding hardly occurred, ∘ indicates that bleeding slightly occurred but was at a level at which there was practically no problem, and x indicates other levels.

5. Water resistance After printing solid images and alphanumeric characters of yellow, magenta, cyan and black inks and leaving them for 1 hour,
It was immersed in tap water having a water temperature of 20 ° C. for 10 seconds. Then, it was taken out from the water, air-dried as it was, and visually evaluated for water resistance. Among yellow, magenta, cyan and black, the ink having the lowest water resistance was used as the water resistance evaluation result.
The water resistance evaluation criteria are as follows.

⊚: The recording agent did not flow out into the margin, and scumming was hardly seen. In addition, there is almost no blurring of alphanumeric characters. ◯: Although the recording material flowed out to the margin part slightly and the alphanumeric characters were slightly blurred, it was at a level where there was no practical problem. X: The recording agent flows out to the margin portion, and the background stain is remarkable. Also, the blurring of alphanumeric characters is terrible. The area where the liquid composition adheres to the recording medium in the above evaluation is the same area as the ink image forming area, and the printing duty is 10 for both the liquid composition and the ink.
It is 0%. Further, the printing direction is unidirectional.

Table 2 shows the evaluation results of the images obtained in Examples 1 to 16 for the above-mentioned evaluation items. As is clear from Table 2, in Examples, images having good fixability, character quality, image density, bleeding and water resistance were obtained.

Table 2 Evaluation results

Example 17 In order to investigate the ejection durability of the liquid composition, an ejection test of the liquid composition (2 × 10
⁹ pulses), and the presence or absence of a change in the ejection amount of the recording head before and after the test was evaluated. As the liquid composition, the liquid compositions of A, B, C and D used in Examples 1 to 4 were used. The discharge amount was measured from the weight change of the liquid composition at 5 × 10 ⁹ pulses, and the results were compared before and after the durability test, and the results are shown in Table 3. As a result, as shown in Table 3, even after applying 2 × 10 ⁹ pulses, the change in the ejection amount did not decrease by 10%, indicating good durability.

Table 3 Evaluation results

[0101]

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, it is possible to prevent kogation of the organic compound on the heat generating head contained in the liquid composition, and to provide an image forming method with improved durability of the recording head.

[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 forming method according to the present invention.

[Explanation of symbols]

 13: Head 14: Ink Grooves 15 and 28: Heating Head 16: Protective Films 17-1 and 17-2: Aluminum Electrode 18: Heating Resistor Layer 19: Heat Storage Layer 20: Substrate 21: Ink 22: Discharge Orifice (Fine Hole) ) 23: Meniscus 24: Ink droplet 25: Recording material 26: Multi-groove 27: Glass plate 40: Ink bag 42: Rubber stopper 44: Ink absorber 45: Ink cartridge 51: Feed unit 52: Feed roller 53: Ejection roller 61: Blade 62: Cap 63: Ink absorber 64: Ejection recovery part 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head part 72: Atmosphere communication port

─────────────────────────────────────────────────── ─── 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 (24)

[Claims] 1. A liquid composition containing at least one cationic substance, which further contains bishydroxyethyl sulfone. 2. The cationic substance has a molecular weight of 1,500 to
The liquid composition according to claim 1, which has a peak of molecular weight distribution in a region of 10,000. 3. One of the cationic substances has a molecular weight of 1,0.
Range of 00 or less, more preferably 100 to 700
The liquid composition according to claim 1 or 2, which has a peak of the molecular weight distribution in the region. 4. Bishydroxyethyl sulfone is 5 to
It is contained in the range of 40% by weight.
The liquid composition according to any one of 1. 5. The liquid composition according to claim 1, further comprising a nonionic polymer. 6. The liquid composition according to claim 1, wherein the cationic substance is contained in the range of 0.05 to 20% by weight. 7. The liquid composition according to claim 1, further comprising water and a water-soluble organic solvent. 8. The liquid composition according to claim 1, wherein the cationic substance is a surfactant. 9. A liquid composition according to claim 1, and at least one color ink selected from each color ink group consisting of yellow, magenta, cyan, black, red, blue and green. An ink set characterized by being combined. 10. The ink set according to claim 9, wherein the liquid composition according to any one of claims 1 to 8 is combined with three color inks of yellow, magenta, and cyan. 11. A liquid composition according to claim 1, and 4 of yellow, magenta, cyan and black.
The ink set according to claim 9, wherein color inks are combined. 12. The ink set according to claim 9, wherein the ink contains an anionic compound. 13. The ink set according to claim 9, wherein the ink contains a water-soluble dye having an anionic group. 14. The ink set according to claim 9, wherein the ink contains a pigment and an anionic compound. 15. A step (A) of adhering the liquid composition according to claim 1 to at least an image forming region of a recording medium, and an ink containing at least an anionic compound. An image forming method comprising: a step (B) of applying the recording medium to the recording medium. 16. The image forming method according to claim 15, wherein the inkjet recording method is an on-demand type inkjet recording method. 17. The image forming method according to claim 15, wherein in step (A), the liquid composition is attached to a recording medium by an inkjet recording method. 18. The image forming method according to claim 15, wherein the inkjet recording method is an inkjet recording method in which thermal energy is applied to the ink. 19. The image forming method according to claim 15, wherein step (A) is performed prior to step (B). 20. The image forming method according to claim 15, wherein step (A) is performed after step (B). 21. An image forming apparatus comprising: the ink set storage unit according to claim 9; and an inkjet recording unit. 22. A first recording unit having a storage portion of the liquid composition according to claim 1 and a discharging means of the liquid composition; and an ink containing at least an anionic compound. An image forming apparatus comprising: a storage section and a second recording unit having the ink ejecting means. 23. The image forming apparatus according to claim 22, wherein the ejection unit is an inkjet recording unit. 24. The image forming apparatus according to claim 22, wherein the ink jet recording means is means for applying thermal energy to the ink to form an ink droplet.