JPH0867063A - Recording medium and image formation using recording medium - Google Patents

Abstract

PURPOSE: To improve the ink absorbency and make dots appear sharply by providing an ink receptor layer containing a water soluble resin and a copolymer of vinylpyrolidone and hydrophobic monomer as essential components, over the entire surface of a base. CONSTITUTION: A recording medium is formed by providing an ink receptor layer containing water soluble resin and a copolymer of vinylpyrolidone and hydrophobic monomer, at least on one surface of a base. The preferred example of the water soluble resin is cationic donatured vinyl alcohol, and the preferred example of the hydrophobic monomer is styrene or (meth)acrylate ester. The preferred example of the base is plastic film or paper. When recording data using this recording medium, an area designated by 'n' on a heat generating head becomes heated rapidly, if an electric signal is fed to electrodes 17-1, 17-2, then bubbles generate in ink 21 which comes into contact with the heated area, and a meniscus 23 protrudes under the pressure of the generated bubbles to discharge the ink 21. Finally, the ink is scattered onto a recording medium 25 as recorded data 24 through an orifice 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium suitable for ink jet recording and an image forming method using the same.

[0002]

2. Description of the Related Art Ink jet recording methods include various ink ejection methods, for example, an electrostatic suction method, a method in which a piezoelectric element is used to mechanically vibrate or displace the ink, and the ink is heated to foam to use its pressure. In this method, small droplets of ink are generated and ejected, and some or all of them are attached to paper or a recording material such as a plastic film coated with an ink receiving layer or paper to perform recording. However, it is attracting attention as a method that can generate high-speed printing and multi-color printing with less noise.

As the ink used in the ink jet recording system, one mainly containing water is used in terms of safety and recording characteristics, and it is a multi-valued ink for preventing nozzle clogging and improving ejection stability. Alcohols are often added.

As a recording medium conventionally used for ink jet recording, a coating layer containing fine silica powder and a water-soluble binder such as polyvinyl alcohol is provided on a base paper as described in JP-B-26665. Recording paper, and glossy paper in which cast coat paper is coated with a film containing polyvinyl alcohol having a saponification degree of 50 to 90 mol% and a cross-linking agent, as described in JP-B-3-25352. As described in JP-A-60-220750, an overhead projector (OHP) recording sheet having a hydrophilic film made of water-soluble polyvinyl alcohol having a saponification degree of 70 to 90 mol% on a polyester film is used. Came.

[0005]

In recent years, with the improvement in the performance of ink jet recording apparatuses such as high speed recording and multicolor recording, more advanced and wide range characteristics have been required for ink jet recording media. . That is, (1) the ink absorption capacity is high (the absorption capacity is large, the absorption time is fast), (2) the optical density of the dots is high, and the periphery of the dots is not blurred. (3) the dot shape is close to a perfect circle. The surroundings should be smooth (4) Characteristics should not change due to changes in temperature and humidity, and curling should not occur (5) Blocking should not occur (6) Images should be stable and do not deteriorate during long-term storage (especially ,
(High-temperature and high-humidity environment) (7) It is required that the recording medium itself is stable and does not deteriorate during long-term storage (especially, in a high-temperature and high-humidity environment).

Further, in the case of OHP recording sheets and the like,
Further, it is also required that the recording medium itself has excellent transparency.

These characteristics are often in a trade-off relationship, and it is impossible to satisfy them at the same time with the conventionally known technology. For example, the above-mentioned recording media of the prior art have a sufficient dot shape and blocking resistance, but since the ink absorption capacity is insufficient, a portion with a high image density, that is, ink ejection Image smearing and density unevenness occur due to ink overflow in a large amount of the area, and especially in the case of color printing, color smearing occurs due to color mixing at the boundary of different colors.

Recently, it has been reported that black ink and color inks having different physical properties such as surface tension are used to reduce bleeding between black and color colors. However, there are few examples of recording materials that exhibit good recording characteristics for inks having different physical properties. Further, in consideration of other properties such as fixability, the one satisfying the overall performance as an OHP film has not yet been obtained.

As described above, as the recording speed is increased, the image density is increased, the color is changed, and the ink is diversified, the ink fixing failure, the image quality deterioration, and the storage stability of the printed matter are serious problems. Has become.

The recording medium provided with an ink receiving layer mainly composed of polyvinylpyrrolidone described in Japanese Patent Publication No. 3-29596 has a relatively good ink absorbing capacity at room temperature and normal humidity, but high temperature and high humidity. The ink below is extremely slow to dry and easily causes blocking. In addition, the recording surface has a weak mechanical strength and is easily scratched.

Further, the recording medium provided with the ink receiving layer mainly composed of polyvinyl alcohol described in the section of the prior art is relatively good in terms of blocking resistance and mechanical strength of the recording surface, but the recording medium. It deteriorates when it is left in a high temperature and high humidity environment for a long time, and the ink absorption capacity deteriorates, and when the image is left in a high temperature and high humidity environment for a long time, dots bleed and the image clarity deteriorates. I have a problem to do.

Further, as described in JP-A-63-221077, the use of polyvinyl acetal as the ink receiving layer solves the problem of ink absorption capacity to some extent, but particularly when recording images at high temperature and high temperature. The image sharpness is not satisfactory when left for a long time in a moist environment.

A recording method using the above-mentioned black ink and color ink having different physical properties such as surface tension is disclosed in JP-A-61-10483 and JP-A-6-10483.
As described in JP-A No. 0-171143, JP-A No. 61-235182, etc., as an ink receiving layer,
By using the cation-modified polyvinyl alcohol, quite satisfactory printing characteristics can be obtained, but sufficient performances other than the image, such as ink fixability and surface stickiness, cannot be obtained.

Further, Japanese Patent Application Laid-Open No. 61-63474 reports that a copolymer of vinylpyrrolidone and vinyl acetate is contained, but the physical properties such as surface tension are different between black ink and color ink. A slight bleeding occurs when using the same. Further, in this recording medium, when recording is performed one after another and inks are sequentially laminated, a slight disturbance is recognized in the image.

Therefore, an object of the present invention is to provide a recording medium which simultaneously satisfies the above-mentioned various characteristics in a well-balanced manner and an image forming method using the recording medium. The recording medium itself or an image is exposed to a high temperature and high humidity environment. Almost no deterioration occurs even if left for a long time, and the fixing property or the stackability of recorded matter,
It is an object of the present invention to provide a recording medium having excellent transportability and continuous paper feeding property, and an image forming method using the recording medium.

[0016]

The above object can be achieved by the present invention described below.

That is, according to the present invention, in a recording medium including a substrate and an ink receiving layer provided on at least one surface of the substrate, the ink receiving layer is a water-soluble resin or a copolymer of vinylpyrrolidone and a hydrophobic monomer. The water-soluble resin is a cation-modified polyvinyl alcohol, the hydrophobic monomer is styrene or a (meth) acrylic acid ester, and the water-soluble resin is The weight content ratio of solid content of the copolymer of vinylpyrrolidone and hydrophobic monomer is 1
In the range of / 100 to 5/1, the base material is a plastic film, and the base material is paper.

Further, the present invention provides a recording medium comprising a substrate and an ink receiving layer provided on at least one surface of the substrate, wherein the ink receiving layer comprises a water-soluble resin, vinylpyrrolidone and a hydrophobic monomer. The recording medium is characterized by containing coalesce and inorganic fine particles as essential components, and having a structure in which a part of the inorganic fine particles protrudes from the surface of the ink receiving layer, and the inorganic fine particles are contained in a solid content of 100 parts of the water-soluble resin. Including 0.05 to 3 parts by weight.

The present invention is an image forming method characterized in that an image is formed on the above-described recording medium by using an ink jet system, and the liquid medium component of the ink is water and a water-miscible glycol or glycol. It is composed mainly of ethers and uses four colors of ink, cyan, magenta, yellow and black, and the surface tension of black ink is the same as that of cyan, magenta and yellow. In comparison, the inkjet method is a method in which thermal energy is applied to ink to eject ink droplets.

[0020]

The present inventors have developed a recording paper suitable for ink jet recording and a transparency film for an overhead projector, and a recording medium coated with the above composition has a very high ink absorption capacity. , The dots are clear and sharp, the blocking resistance is excellent, the change in performance is small even with changes in environmental conditions such as temperature and humidity, and the recording medium is stable for long-term storage especially in a high temperature and high humidity environment, Further, they found that a stable image can be formed for long-term storage in a high temperature and high humidity environment, and that they are excellent in fixing property, print material stacking property, transporting property, and continuous paper feeding property, and to complete the present invention. It has come.

That is, by containing a copolymer of vinylpyrrolidone and a hydrophobic monomer and a water-soluble resin in the ink receiving layer, the affinity for ink having various characteristics, especially water, water-miscible glycols or glycol ethers is obtained. It is considered that the affinity for inks is enhanced, the ink absorption capacity is extremely high, and a dot is clear and a sharp image can be obtained. Further, the change in performance is small even when the environmental conditions such as temperature and humidity change. With such a configuration, it becomes possible to satisfy the overall performance of the OHP film.

Further, by having a structure in which a part of the inorganic fine particles are projected from the surface of the binder layer of the ink receiving layer, the catching property on the pickup roller of various printers is improved, and the transporting property without delay can be realized. Further, by adopting the constitution of the present invention, since the blocking property is also good, the performance which is very satisfactory also in the continuous paper feeding property can be obtained.

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

The copolymer of vinylpyrrolidone and the hydrophobic monomer used in the present invention is mainly supplied as an aqueous dispersion, and has an ink affinity in the vinylpyrrolidone portion and a film in the hydrophobic monomer portion. It is considered that the effects of the present invention can be obtained by having mechanical properties, environment resistance, and the like.

Examples of the hydrophobic monomer used include aromatic vinyl compounds such as styrene, α-methylstyrene and vinylnaphthalene, (meth) acrylic acid esters, and esters of unsaturated carboxylic acids such as crotonic acid, and
Examples thereof include vinyl acetate and vinyl butyrate, but are not particularly limited as long as they can be copolymerized with vinylpyrrolidone.

Among these hydrophobic monomers, preferred are styrene and (meth) acrylic acid ester, which are compatible with various properties such as printability with respect to various inks, image quality, blocking resistance, and stackability of recorded matter. .

The composition ratio of vinylpyrrolidone to the hydrophobic monomer is preferably in the range of 1/9 to 9/1, and the molecular weight is preferably in the range of 500 to 1,000,000.

Next, the water-soluble resin used in the present invention is not limited as long as it can accept a so-called aqueous ink and exhibits solubility or affinity for the aqueous ink. Unmodified polyvinyl alcohol, anion-modified Polyvinyl alcohol, cation-modified polyvinyl alcohol, polyurethane, carboxymethyl cellulose, polyester, polyacrylic acid (ester), hydroxyethyl cellulose, melamine resin, synthetic resins such as modified products thereof, albumin, gelatin, casein, starch, cationization Examples thereof include, but are not limited to, natural resins such as starch, gum arabic, and sodium alginate. It is also possible to use a plurality of these simultaneously.

Among these water-soluble resins, cation-modified polyvinyl alcohol can be particularly preferably used. By using this cation-modified polyvinyl alcohol, a good image can be obtained especially for various inks having various characteristics. This cation-modified polyvinyl alcohol will be described in detail below.

The cation-modified polyvinyl alcohol (hereinafter, abbreviated as PVA) used in the present invention means a cationic group such as a primary to tertiary amino group or a quaternary ammonium salt group in the main chain or side chain. It is PVA in the chain.

Generally, PVA can be obtained by saponifying polyvinyl acetate by an acid saponification method or an alkali saponification method. The cation-modified PVA used in the present invention is a conventional PVA obtained by converting ordinary PVA into glycidyltrimethylammonium chloride or the like. And a cationic agent having a group capable of reacting with a hydroxyl group of PVA at the same time as a cationic group, or a saponification by copolymerizing vinyl acetate and a monomer having another reactive group. Then, by utilizing such a reactive group, a method of reacting a cationic group-containing compound to cationically modify PVA, or
When the raw material vinyl acetate is polymerized, a cationic monomer is added for copolymerization, and the resulting copolymer is saponified by a conventional method.

As the cationic monomer used for such copolymerization, vinyloxyethyltrimethylammonium chloride, 2,3-dimethyl-1-vinylimidazolium chloride, trimethyl- (3-methacrylamidopropyl) ammonium chloride, or These precursors primary to tertiary amines, N- (1,1-dimethyl-3-dimethylaminopropyl) acrylamide, N
-(3-dimethylaminopropyl) methacrylamide,
o-, m-, p-aminostyrene or a monoalkyl or dialkyl derivative thereof or a quaternary ammonium salt thereof; o-, m-, p-vinylbenzylamine or a monoalkyl or dialkyl derivative thereof or a primary thereof Quaternary ammonium salt; N- (vinylbenzyl) pyrrolidine; N- (vinylbenzyl) piperidine;
N-vinylpyrrolidone; α-, β-vinylpyridine or a quaternary ammonium salt thereof; α-, β-piperidine or a quaternary ammonium salt thereof; 2-, 4-
Vinyl quinoline or other nitrogen-containing heterocyclic vinyl compounds such as quaternary ammonium salts thereof, or vinyl compound monomers which can be easily converted into cationic groups such as nitro derivatives thereof are mentioned. Considering stability when saponifying a group, vinyloxyethyltrimethylammonium chloride, 2, 3
-Dimethyl-1-vinylimidazolium chloride, trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride, trimethyl- (3-
Methacrylamidopropyl) ammonium chloride,
Alternatively, these precursors primary to tertiary amines, N-
(1,1-Dimethyl-3-dimethylaminopropyl) acrylamide, N- (3-dimethylaminopropyl) methacrylamide and the like are preferable.

The amount of the cationic groups present in the cation-modified PVA as described above is expressed by the mole fraction of the monomer units in the polymer, and the cationic groups account for 0.05 to 30 mol% of all the monomer units, More preferably 0.1-10
It is within the range of mol%. The amount of cationic groups present is 0.0
If it is less than 5 mol%, the water resistance and resolution of the ink receiving layer,
Ink jet recording physical properties such as color developability are not sufficiently effective as compared with non-modified ones. On the other hand, when it exceeds 30 mol%, the adhesive strength of the ink receiving layer to the substrate and the film forming property are poor. Further, it will also affect the miscibility with the aqueous resin emulsion, which will be described later.

The degree of saponification of PVA, which is the trunk polymer, is preferably 70 to 99 mol%. Furthermore, the degree of polymerization of cation modification of PVA is 3
Those having a degree of polymerization of 500 to 3000 are preferable, and those having a degree of polymerization of 500 to 3000 are more preferable.
Further, in any case, those having different degrees of polymerization and saponification may be mixed and used.

The weight content ratio of the water-soluble resin and the copolymer of vinylpyrrolidone and the hydrophobic monomer as described above in the solid content is preferably in the range of 1/100 to 5/1, more preferably 3 It is desirable to be in the range of / 100 to 3/1. If this ratio is less than 1/100, the effects of the present invention, particularly the blocking resistance and the stackability of recorded matter, are not sufficient, and if it exceeds 5/1, the haze degree (cloudiness) of the film is increased. Is very high.

Next, examples of the inorganic fine particles used in the present invention include silica, alumina, aluminum silicate, magnesium silicate, basic magnesium carbonate, talc, clay, hydrotalcite, calcium carbonate, titanium oxide, zinc oxide and the like. It is possible, but of course not limited to these. And, these inorganic fine particles do not need so much ink absorbency.

For example, when high-quality aqueous resin particles are used as fine particles, the resin particles themselves also absorb ink and swell. As a result, the mechanical strength of the resin particles is lowered, the catching property on the pickup roller is greatly reduced, and the transportability and the continuous sheet feeding property are not practical.

In this case, by using the inorganic fine particles, the mechanical strength after printing can be maintained, so that the object of the present invention can be satisfied.

As a method of producing a structure in which a part of the inorganic fine particles are projected from the binder layer surface of the ink receiving layer, the primary particle diameter (diameter) of the fine particles to be used or the secondary particles for fine particles which easily aggregate are used. When the diameter (diameter) or the average particle diameter is larger than the thickness of the binder layer, the inorganic fine particles are surely projected from the surface of the binder layer of the ink receiving layer. Further, even if the primary particle diameter of the fine particles to be used is smaller than the thickness of the binder layer, the fine particles existing on the surface result in the inorganic fine particles protruding beyond the surface of the binder layer of the ink receiving layer. It can also be configured. Furthermore, since it is sufficiently possible that they are present in an aggregated state (secondary particles) (generally, they are present in this form), the inorganic fine particles are projected even when fine particles having a small diameter are used. The configuration is possible.

However, when the average particle diameter (diameter) of these inorganic fine particles exceeds 5 times the thickness of the binder layer of the ink receiving layer, the surface strength is reduced and the powder is reduced.
Not preferred. Further, even when the average particle diameter (diameter) of these inorganic fine particles is 1/5 or less of the thickness of the binder layer, as a result, a structure in which the inorganic fine particles are projected beyond the surface of the binder layer is obtained. It is possible to take. However, when the inorganic fine particles having an average particle diameter of ⅕ or less of the thickness of the binder layer are used, the effect for sufficiently exerting the present invention, that is, satisfactory transportability and continuous paper feedability are satisfied. Therefore, the amount used becomes considerably large, the transparency becomes low (the haze degree becomes high), and it deviates from the practical range as an OHP film.

In order to suppress this transparency or surface glossiness within the range of practical use, it is 1/5 of the thickness of the binder layer.
It is necessary to use inorganic fine particles having the above average particle diameter.

In the most preferred embodiment of the present invention,
The use of inorganic fine particles larger than the thickness of the binder layer can be mentioned.

The content of these inorganic fine particles is 0.10 with respect to 100 parts of the solid content of the water-soluble resin which is the binder component.
About 05 to 3 parts is preferable. If this amount is less than 0.05 parts, the effect of the present invention will not be sufficiently exhibited, and if 3
If it exceeds the area, it is not preferable from the viewpoint of translucency or surface gloss.

Further, in the present invention, a cationic compound may be further contained for the purpose of improving image storability. The cationic compound is not particularly limited as long as it contains a cationic moiety in the molecule, and examples thereof include monoalkylammonium chloride, dialkylammonium chloride, tetramethylammonium chloride, trimethylphenylammonium chloride and ethylene oxide-added ammonium. Quaternary ammonium salt type cationic surfactants such as chloride, or amine salt type cationic surfactants, and
An amphoteric surfactant such as an alkyl betaine containing a cationic moiety, imidazolium betaine, or alanine may be used.

As the polymer or oligomer, a cation-modified polyacrylamide or a copolymer of acrylamide and a cationic monomer, polyethyleneimine, polyamide-epichlorohydrin resin, polyvinylpyridinium halide, various polyamine resins such as polyallylamine and polyamine are used. Examples thereof include sulfone and polyvinylamine.

Further, vinyl oxazolidone type monomers alone or copolymers with other general monomers,
Examples thereof include vinyl imidazole-based monomers alone or copolymers with other general monomers. The above-mentioned general monomers include methacrylate, acrylate, acrylonitrile, vinyl ether, vinyl acetate,
Examples thereof include ethylene and styrene. Also, cation-modified cellulose or the like may be used.

The above-mentioned cationic compounds are preferably used, but of course, the cationic compounds are not limited to these.

The content of these cationic compounds in the ink receiving layer is preferably in the range of 0.01 to 30% by weight based on the content of the water-soluble resin in the ink receiving layer.

If this amount is less than 0.01% by weight,
The effect of forming a stable image on long-term storage in a high temperature and high humidity environment is not remarkable as compared with the case of no addition, and 3
If it exceeds 0% by weight, the hygroscopicity becomes too strong, blocking is likely to occur, and the mechanical strength of the recording surface is weak and scratches are likely to occur.

Of course, in the constitution according to the present invention, the above-mentioned cationic compound is not an essential component but merely shows an auxiliary role.

Furthermore, a cross-linking agent may be included, such as, but not limited to, methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, and isocyanate.

In the present invention, the above water-soluble resin, a copolymer of vinylpyrrolidone and a hydrophobic monomer, and a composition containing inorganic fine particles as essential components are coated on at least one surface of the substrate to form a substrate. The recording medium has an ink receiving layer on its surface.

Specific examples of the additives include various surfactants, dye fixing agents (waterproofing agents), defoaming agents, antioxidants,
Optical brightener, ultraviolet absorber, dispersant, viscosity modifier, PH
Examples include regulators, antifungal agents, and plasticizers. These additives may be arbitrarily selected from conventionally known compounds according to the purpose.

Examples of the base material constituting the recording medium of the present invention include high-quality paper, medium-quality paper, art paper, bond paper, recycled paper, baryta paper, cast coated paper, cardboard paper, polyethylene terephthalate, and diterephthalate. Acetate, triacetate, cellophane, celluloid, polycarbonate, polyimide, polyvinyl chloride, polyvinylidene chloride, film or plate made of plastic such as polyacrylate, polyethylene, polypropylene, glass plate, ceramics, or cotton, rayon, acrylic, nylon, silk, Cloth such as polyester can be used. It is appropriately selected from the above-mentioned base materials depending on the recording purpose of the recording medium, the use of the recorded image, or various conditions such as adhesion to the composition coated on the upper side thereof.

An OHP film can be formed by using a transparent material such as a plastic film as the base material, and a glossy paper can be formed by using an opaque material such as paper as the base material.

In preparing the recording medium of the present invention, first, the above composition, if necessary together with other additives, are added.
A coating liquid is prepared by dissolving or dispersing in water or alcohol, polyhydric alcohols or other appropriate organic solvent.

The obtained coating liquid is applied, for example, to a roll coater method, a blade coater method, an air knife coater method, a gate roll coater method, a bar coater method, a size press method, a spray coat method, a gravure coater method, a curtain coater method, etc. To coat the surface of the substrate. After that, it is dried using, for example, a hot air drying oven or a heating drum to obtain the recording medium of the present invention.

The total coating amount of the ink receiving layer is 0.2 to 50 g / m ² , more preferably 1 to 30 g / m 2.
It is within the range of ² . When the coating amount is small, a part of the substrate may be exposed on the surface. This coating amount is 0.2 g /
If less than m ^2, the sufficient effect can not be obtained in terms of color development of the paint compared to the case where not provided with an ink receiving layer, on the other hand, especially in the case of providing beyond 50 g / m ² ,
The occurrence of curling becomes remarkable in a low temperature and low humidity environment. When the coating amount is expressed by the thickness, the coating amount is 0.5 to 100 μm.
The range in which the thickness becomes is preferable.

As the ink itself for carrying out ink jet recording on the recording medium described above, known inks can be used without any problems. Also, as the recording agent, a direct dye,
Acid dyes, basic dyes, reactive dyes, water-soluble dyes typified by food dyes, dispersible dyes, and pigments can be used, and can be used without particular limitation as long as they are those for ordinary inkjet recording. I can.

Such a water-soluble dye or dispersible dye,
The pigment is preferably used in a proportion of about 0.1 to 20% by weight in the ink.

The solvent used in the aqueous ink used in the present invention is water or a mixed solvent of water and a water-miscible organic solvent,
Particularly preferred is a mixed solvent of water, a water-miscible organic solvent and a water-soluble miscible organic solvent containing a polyhydric alcohol having an effect of preventing ink drying.

The method for applying the above-mentioned ink to the above-mentioned recording medium for recording is preferably an ink jet recording method, and this method is a range which effectively separates the ink from the nozzle. Any method may be used as long as it can apply ink to the recording medium.

Particularly, in the method described in Japanese Patent Laid-Open No. 54-59936, the ink subjected to the action of thermal energy undergoes a rapid volume change, and the action force due to this state change ejects the ink from the nozzle. The inkjet method can be effectively used.

An example of an ink jet recording apparatus suitable for recording using the recording medium of the present invention will be described below. An example of a head configuration that is a main part of the apparatus is shown in FIGS.
And shown in FIG.

The head 13 is a glass, ceramics, or plastic plate having a groove 14 through which ink passes, and a heating head 15 used for heat-sensitive recording (a head is shown in the drawing, but is not limited to this). It is obtained by bonding and. The heating head 15 includes a protective film 16 made of silicon oxide, aluminum electrodes 17-1 and 17-.
2. A heating resistor layer 18 made of nichrome or the like, a heat storage layer 19, and a substrate 20 having a good heat dissipation property such as alumina.

The ink 21 has a discharge orifice (fine hole) 2
2, the meniscus 23 is formed by the pressure P.

Now, 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 23 is projected by the pressure, the ink 21 is ejected, and the recording droplet 24 is made from the orifice 22 and is ejected toward the recording medium 25. FIG. 3 shows an external view of a multi-head in which many heads shown in FIG. 1 are arranged. The multi-head includes a glass plate 27 having multi-grooves 26, and FIG.
The heating head 28 similar to that described in FIG.

Incidentally, FIG. 1 shows the head 1 along the ink flow path.
3 is a sectional view of FIG. 3, and FIG. 2 is a sectional view taken along the line AB of FIG. 1.

FIG. 4 shows an example of an ink jet recording apparatus incorporating such a head. In FIG. 4, 61
Is a blade serving 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 cantilever. The blade 61 is disposed adjacent to the recording area by the recording head, and in the case of this example, is held in a protruding form in the movement path of the recording head. Reference numeral 62 denotes a cap, which is disposed at a home position adjacent to the blade 61, and has a configuration in which it moves in a direction perpendicular to the moving direction of the recording head and contacts the ejection port surface to perform capping. Further, 63 is an ink absorber provided adjacent to the blade 61, and like the blade 61,
The recording head is held in a protruding form in the moving path of the recording head.
The blade 61, the cap 62, and the absorber 63 constitute a discharge recovery unit 64, and the blade 61 and the absorber 6
By the means 3, water, dust and the like are removed from the ink ejection port surface.

Reference numeral 65 denotes a recording head having ejection energy generating means, which ejects ink to a recording medium facing the ejection port surface on which ejection ports are arranged for recording, and 66 denotes a recording head 65 in which the recording head 65 is mounted. It is a carriage for moving the. The carriage 66 slidably engages 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 designates a paper feed section for inserting a recording medium, and 5
A paper feed roller 2 is driven by a motor (not shown). With these configurations, the recording medium is fed to the position facing the ejection port surface of the recording head, and as the recording progresses, the sheet discharge roller 53 is arranged and the sheet is discharged.

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 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 protruding surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as the above-mentioned position at the time of wiping. As a result, the ejection opening surface of the recording head 65 is wiped even during this movement.

The above-described movement of the recording head 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 adjacent to the recording area at a predetermined interval while the recording head moves in the recording area for recording. The wiper is moved to the position, and the wiping is performed along with the move.

[0075]

The present invention will be described in more detail with reference to the following examples. In the text, “part” or “%” is based on weight unless otherwise specified.

Example 1 Cation-modified polyvinyl alcohol (trade name: CM-3
18, Kuraray, saponification degree about 89 mol%, degree of polymerization about 17
00, cationization degree about 2 mol%) 100 parts, copolymer of vinylpyrrolidone and styrene (trade name: Antara 43
No. 0, ISP Japan Co., Ltd., solid content 40%) was dissolved and dispersed in a composition of 20 parts in terms of solid content in water as a medium. The obtained coating liquid was applied to a polyethylene terephthalate film (thickness 100 μm,
Product name: Lumirror, manufactured by Toray), coating thickness after drying is 10
After being coated so as to have a thickness of μm, the recording medium of the present invention was prepared by drying at 120 ° C. for 3 minutes.

Color recording was performed on the above-mentioned recording medium under the following conditions by an ink jet recording apparatus in which the ink having the following composition was used and the ink was foamed by thermal energy to eject the ink.

Ink composition (Bk) C.I. I. Direct Black 19 3 parts Glycerin 6 parts Ethylene glycol 5 parts Urea 5 parts Isopropyl alcohol 3 parts Water 78 parts The surface tension of this ink was about 45 dyne / cm.

Ink composition (Y, M, C) Dye 4 parts Glycerin 7 parts Thiodiglycol 7 parts Urea 7 parts Acetylene glycol 1.5 parts Water 73.5 parts The surface tension of this ink was about 35 dyne / cm. .

Dye Y: C.I. I. Direct Yellow 86 M: C.I. I. Acid Red 23 C: C.I. I. Direct Blue 199

Recording conditions Ejection frequency: 4 KHz Ejection droplet capacity: 45 pl Recording density: 360 DPI Maximum single-color ink application amount: 8 nl / mm ²

Example 2 A recording medium was prepared and color recording was carried out in the same manner as in Example 1 except that the copolymer of vinylpyrrolidone and styrene was changed to 5 parts in terms of solid content in Example 1. .

Example 3 A recording medium was prepared and color recording was carried out in the same manner as in Example 1 except that the copolymer of vinylpyrrolidone and styrene was changed to 100 parts in terms of solid content. .

Example 4 A recording medium was prepared and color recording was carried out in the same manner as in Example 1 except that the copolymer of vinylpyrrolidone and styrene was changed to 300 parts in terms of solid content. .

Example 5 In Example 1, a copolymer of vinylpyrrolidone and styrene was used as a copolymer of vinylpyrrolidone and ethyl acrylate (trade name; Antara 130, manufactured by ISP Japan Co., Ltd.,
A recording medium was prepared in the same manner as in Example 1 except that the solid content was 40%), and color recording was performed.

Example 6 In Example 1, the cation-modified polyvinyl alcohol was replaced with another cation-modified polyvinyl alcohol (trade name: C
-506, manufactured by Kuraray Co., Ltd., saponification degree: about 74-80 mol%, polymerization degree: about 500, cationization degree: about 1 mol%), a recording medium was prepared in the same manner as in Example 1, and color recording was carried out. It was

Example 7 In Example 1, the cation-modified polyvinyl alcohol was replaced with unmodified polyvinyl alcohol (trade name: PVA21).
7, made by Kuraray, saponification degree about 88 mol%, degree of polymerization about 170
A recording medium was prepared and color recording was performed in the same manner as in Example 1 except that (0) was used.

Example 8 A recording medium was prepared in the same manner as in Example 1 except that the cation-modified polyvinyl alcohol was polyvinyl acetal (trade name; KW-1, manufactured by Sekisui Chemical Co., Ltd.), and color recording was performed. went.

Example 9 In Example 1, cation-modified polyvinyl alcohol was replaced with hydroxyethyl cellulose (trade name; AL-15,
A recording medium was prepared in the same manner as in Example 1 except that it was manufactured by Fuji Chemical Co., Ltd., and color recording was performed.

Example 10 In Example 1, the cation-modified polyvinyl alcohol was mixed with polyethylene oxide (trade name; Alcox R-
1000, manufactured by Meisei Kagaku Co., Ltd., and a recording medium was prepared in the same manner as in Example 1, and color recording was performed.

Example 11 Example 1 was repeated except that the copolymer of vinylpyrrolidone and styrene was changed to the copolymer of vinylpyrrolidone and vinyl acetate (trade name: S360, manufactured by ISP Japan Co., Ltd.). A recording medium was prepared in the same manner as in 1, and color recording was performed.

Examples 12 and 13 The recording medium of the present invention was prepared in the same manner as in Example 1 except that art paper and fine paper were used as the base materials,
Color recording was performed.

Comparative Example 1 In Example 1, a copolymer of vinylpyrrolidone and styrene was used as a polyvinylpyrrolidone homopolymer (trade name: K-
60, manufactured by ISP Japan Co., Ltd., but in Example 1
A recording medium was prepared in the same manner as in 1. and color recording was performed.

Comparative Example 2 A recording medium was prepared in the same manner as in Example 1 except that the cation-modified polyvinyl alcohol was used without using the copolymer of vinylpyrrolidone and styrene, and color recording was carried out. I went.

Comparative Example 3 A recording medium was prepared in the same manner as in Example 7 except that the unmodified polyvinyl alcohol was not used and the copolymer of vinylpyrrolidone and styrene was not used. I went.

The following items were evaluated for the obtained color print samples.

(Evaluation Items) (1) Solid Uniformity Black Part and Color Part (Y, M, C and R, G, B)
Regarding the beading, the beading was clearly observed on the projected image or visually, and the unevenness was conspicuous x, the slight beading was △, the beading was not generated at all, and the unevenness was ○. And Here, the beading means that when the ink has fluidity before being fixed on the ink receiving layer, dots irregularly move in the surface direction of the surface of the ink receiving layer, and adjacent dots and new dots. Is a phenomenon in which density unevenness is generated in a recorded image by forming an aggregate of.

(2) Bleed between black and color Black part and color part (Y, M, C and R, G, B)
When the bleeding was clearly generated between the boundaries, the sample was marked with X, the sample with slight bleeding was marked with Δ, and the sample with no bleeding was marked with O.

(3) Fixability In an environment of 25 ° C./60%, after recording with full dots of black and two colors of yellow, cyan and magenta, and leaving for 2 minutes, the black part and the color part, that is, NP-DRY paper (manufactured by Canon) is overlaid on each of the two full-color areas of yellow, cyan, and magenta, and rubbed with a pressure of 4 Kg / cm ² from the top to reveal the paper when peeled off. When the ink was transferred to the surface and the recording part was clearly scratched, x was given, and when some transfer was observed and small scratches were given, Δ was given, and when no transfer or scratch was observed, it was given as o. .

(4) Recorded Product Loading Property When recording is successively performed using an A4 size recording medium and the obtained recorded products are sequentially laminated, the case where the image disturbance due to the lamination is clearly recognized When there was some recognition, it was evaluated as Δ, and when it was not recognized at all, it was evaluated as ○.

(5) OHP suitability A recorded image is projected on a screen by an OHP and visually observed and judged, and a recorded image is bright, a recorded image has a high optical density, a high contrast, and a clear and easily projected image is obtained. Yes, the optical density of the recording area is slightly low,
What was observed as dark was evaluated as Δ, and when the recorded part was clearly dark, had low optical density and lacked fineness, was evaluated as x.

(6) Image storability The image storability was determined by storing the images recorded on the respective recording media using the above printer for 7 days in a 35/90% environment before storing the images. It was compared and evaluated. As compared with the image before being stored, the ink was overflowed, bleeding out, and the characters were thickened, and the image quality was remarkably inferior, x, no change was observed, and medium was evaluated as Δ.

(7) Film Haze The images recorded on the respective recording media by using the above printers are projected by a transmissive OHP projector, and when the images are clearly cloudy and the images are dark, there is no problem. The ones were evaluated as ◯, and those slightly darker were evaluated as Δ.

The evaluation results are summarized in Table 1.

Example 14 The coating composition of Example 1 was mixed with silica fine particles (Silbead D-
MS, average particle size 30 μm, manufactured by Mizusawa Chemical Co., Ltd.) was used to prepare a recording medium having a structure in which a part of the inorganic fine particles were projected from the ink receiving layer in the same manner as in Example 1 except that 0.8 part was added in terms of solid content. Prepared.

When this recording medium was evaluated in the same manner as in Example 1, the same effect as in Example 1 was obtained. Furthermore,
This recording medium is used for Canon bubble jet printer B.
When 10 sheets were continuously fed to JC-600 (trade name),
I was able to feed paper without delay. Also, when 30 sheets of this recording medium were set in the auto seed feeder of the above printer and full-color images were continuously printed, printing could be performed without delay,
Even after being left for 20 minutes after printing, the recording media did not adhere to each other.

[0107]

[Table 1]

[0108]

As described above, according to the present invention, various inks having various characteristics have excellent ink absorbency, clear dots, high optical density, and excellent bleeding. Not only is it possible to form high-definition images, but it is also excellent in ink fixability, recording material stackability, transportability, and continuous paper feedability. Furthermore, even if the image is left in a high temperature and high humidity environment for a long time, it deteriorates. It is now possible to supply a recording medium with ideal performance requirements that is excellent in image storage stability.

[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.

[Explanation of symbols]

 13 heads 15 and 28 heat generating head 21 ink 25 recording medium 61 wiping member 65 recording head 66 carriage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 27/28 9349-4F 27/30 102 9349-4F

Claims (13)

[Claims] 1. A recording medium comprising a base material and an ink receiving layer provided on at least one surface of the base material, wherein the ink receiving layer comprises a water-soluble resin and a copolymer of vinylpyrrolidone and a hydrophobic monomer as essential components. A recording medium characterized by containing as. 2. A recording medium comprising a substrate and an ink receiving layer provided on at least one surface of the substrate, wherein the ink receiving layer is a water-soluble resin, a copolymer of vinylpyrrolidone and a hydrophobic monomer, and inorganic fine particles. Contains as an essential ingredient,
A recording medium having a structure in which a part of the inorganic fine particles are projected from the surface of the ink receiving layer. 3. The recording medium according to claim 2, wherein the inorganic fine particles are contained in an amount of 0.05 to 3 parts based on 100 parts of the solid content of the water-soluble resin. 4. The recording medium according to claim 1, wherein the water-soluble resin is a cation-modified polyvinyl alcohol. 5. The recording medium according to claim 1, wherein the hydrophobic monomer is styrene or (meth) acrylic acid ester. 6. The solid content weight ratio of the copolymer of the water-soluble resin, vinylpyrrolidone and hydrophobic monomer is 1 /.
The recording medium according to claim 1, which is in the range of 100 to 5/1. 7. The recording medium according to claim 1, wherein the substrate is a plastic film. 8. The recording medium according to claim 1, wherein the base material is paper. 9. An image forming method, wherein an image is formed on the recording medium according to claim 1 by using an inkjet method. 10. The image forming method according to claim 9, wherein the liquid medium component of the ink is mainly composed of water and a water-miscible glycol or glycol ether. 11. The image forming method according to claim 9, wherein four color inks of cyan, magenta, yellow and black are used as the ink. 12. The surface tension of black ink is cyan,
The image forming method according to claim 11, wherein the surface tensions of the inks of three colors of magenta and yellow are high. 13. The image forming method according to claim 9, wherein the inkjet system is a system in which thermal energy is applied to the ink to eject ink droplets.