JPS59201891A - Treatment of recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes the entire inkjet recording method that forms characters and images by flying minute ink liquids 7'11-, and the entire recorded image has excellent color reproducibility, water resistance, gloss, etc. It relates to a method of forming on a recording medium.

In recent years, inkjet recording methods are characterized by high speed, high resolution, low noise, easy multicolor printing, and great flexibility in recording patterns. It is rapidly becoming popular in many applications.

In particular, it is attracting attention as a means of obtaining color hard copies for computer terminals, etc. by taking advantage of the fact that various ink liquids can be used and the recording pattern is highly flexible.

Furthermore, the images formed by the multicolor inkjet method are comparable to those produced by normal multicolor printing, and when the number of copies to be produced is small, it is cheaper than the normal plate making method. Attempts are being made to apply it to the field of color photographic printing.

In general, inkjet recording methods include a charge amount control method, a pressurized vibrator such as a low-field control method, an electrostatic acceleration type in which the ink is ejected electrostatically accelerated by a voltage between a counter electrode, and a pressure pulse that discharges the ink completely. There are on-demand pressure pulse type methods that generate mist, and ink mist methods that generate mist using ultrasonic vibrations, but in either case, a recorded image is obtained by making all liquid ink droplets adhere to the recording medium. be.

High-quality paper and coated paper used for general printing, baryta paper and resin-coated paper used as a base for photographic paper, and transparent polymer films used as light-transmissive recording media for overhead projectors, etc., are ink-free. Because the absorbency is extremely poor, when used for inkjet recording, the ink remains on the surface for a long time and may touch parts of the device! jQ ', 1'! , someone touched it,
If consecutively ejected sheets overlap and the recording surface is rubbed, the image may become smeared or run due to residual ink, resulting in Xt + Bright image 1! ! K It is difficult to attend. Therefore, it has been impossible to perform clear inkjet recording on these recording media using conventional water-based inks. If a highly volatile oil-based ink is used, the image dries quickly and does not have the above disadvantages, but it is not preferable in terms of odor, toxicity, etc.

Therefore, when recording using the inkjet recording method, ink, especially water-based ink, has good absorbency, and ink droplets adhering to the recording medium are quickly absorbed into the ink receiving layer and appear to be on the surface. The recording medium is required to ensure that the diameter of the absorbed ink dots does not become larger than necessary. Furthermore, when it became possible to obtain various color hard copies as a computer terminal printer or grotter, overhead projectors became available.
Inkjet images can be obtained on transparent films that can also be used as optical projection type recording media, such as
There has been a demand for inkjet recording media with glossy surfaces, such as multicolor printing on photographic paper or coated paper.

In general, an ink-absorbing ink-receiving layer needs to have many voids to absorb and retain ink, and therefore an ink-receiving layer with many voids naturally has a large number of interfaces with air and has a surface with microscopic irregularities. Having a large amount of light causes total diffuse reflection of light and prevents it from passing through, making it glossy and opaque.

Furthermore, since it becomes difficult for light to reach the ink that has penetrated into the voids, the colors of the image become dull and the color reproducibility and color density are reduced.

The present invention was achieved by studying various methods for producing clear inkjet recorded images on completely transparent or opaque recording media, and is composed mainly of thermoplastic organic polymer fine particles and an adhesive on a support. A receiving layer with good ink absorption property is provided, and after all of the ink is jetted by an inkjet device to form a recorded image on the ink receiving surface, the ink receiving layer is formed by applying a solvent for the thermoplastic organic polymer to the ink receiving layer. The present invention provides a method for processing a recording medium that eliminates voids therein and forms a transparent film in which ink is trapped in the layer.

The present invention will be explained in detail below. The support used in the present invention may be a transparent film such as polyester, polysulfone, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, cellulose acetate, polyethylene, or polypropylene, or a white pigment added to these films at 3° In addition, opaque sheet-like materials such as general paper, coated paper, baryta paper, register/coated paper, and pot metal foil can be used. Examples of white pigments filled in the paper layer or film layer include titanium oxide, calcium sulfate, calcium carbonate, silica, clay, talc, and many other materials commonly used as fillers, pigments for paints, and kneading. are available. There are no particular limitations on the thickness of these supports, but those of 10 μm to 300 μm are usually used. Furthermore, in order to completely improve the contact between the film and the ink-receiving layer, it is also possible to carry out general treatments such as corona discharge treatment and flame treatment that completely improve the adhesion, or to remove the entire undercoat layer.

In this case, a resin layer such as gelatin or nitrocellulose is usually used as the subbing layer.

The ink-receiving layer provided on the support is made of finely divided thermoplastic organic polymer as a main material in order to provide ink-absorbing ability, and can be easily applied by adding an appropriate amount of adhesive and drying. The composition of the fine particulate thermoplastic organic polymer includes, for example, polymonobinylidene aromatics such as polystyrene, polymethylstyrene, polymethoxystyrene, and polychlorostyrene, polyvinyl chloride, polyvinyl-cyclohexane, polyethylene, and polypropylene. , polyolefins such as polyvinylidene chloride and polyhaloolefins,
These include esters of α, β-ethylenically unsaturated acids such as polymethacrylate, polychloroacrylate, and polymethylmethacrylate, and copolymers thereof.

The fine particulate thermoplastic organic polymer used in the present invention is preferably a so-called slurry-like plastic pigment made by emulsion polymerization of one or more vinyl monomers, or its dry irN! It can be obtained as a fine powder or a powder formed into fine particles by pulverizing all types of plastics and solid plastics by various means. The size of these thermoplastic organic polymer fine particles usually ranges from o, o iμm to
By forming the particles into fine particles with a diameter of 50/im, preferably 0.05 μm to 30 μm, all the voids necessary for completely absorbing the ink can be formed in the ink-receiving layer.

In the present invention, these organic fine particles are used as the main pigment, and 2 parts to 30 parts, preferably 5 parts to 20 parts of an adhesive is mixed with the main pigment, and the mixture is dispersed in water or a suitable solvent to form a paint. It is coated on the support and dried to form an ink-receiving layer.

Examples of adhesives used in the ink receiving layer include oxidized starch, etherified starch, esterified starch, starches such as dextrin, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein,
Gelatin, soy protein, polyvinyl alcohol and its derivatives, maleic anhydride resin, conjugated diene polymer latex such as ordinary styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, polymers of acrylic esters and methacrylic esters. Acrylic polymer latex such as a polymer or copolymer, vinyl polymer latex such as ethylene-vinyl acetate copolymer, or functional group-modified polymerization using a monomer containing a functional group such as a carboxyl group of these various polymers. Thermosetting synthetic resin adhesives such as coalescing latex, melamine resin, urea resin, etc. are used. In addition, cationically modified starch and polyvinyl alcohol
-It is also possible to use together various cationic resins and the like.

Furthermore, if necessary, there is no problem in appropriately distributing additives such as dispersants, thickeners, flow modifiers, antifoaming agents, foaming agents, molding agents, coloring agents, etc.

Coating machines include blade coaters, air knife coaters, etc., which are generally used in the production of pigment-coated paper.
Any of a roll coater, plush coater, curtain coater, chamber coater, bar coater, gravure coater, etc. can be applied.

Drying after application is done using a normal drying method such as a gas heater,
Dry using an electric heater, steam heating heater, hot air heating, etc. to form a 7-layer coating. At that time, it is necessary that the temperature added to the coating layer be below the melting point of the thermoplastic particles (74 polymer fine particles) used. If drying is continued, the organic pigment will melt and form a film, which will reduce the ink absorbency, which is an important element of the ink-receiving layer.

The coating layer may have a certain thickness at one time, or it is possible to provide the necessary suitability by applying two or more layers.

In the present invention, as a method for applying ink into an ink-receiving layer, that is, as an inkjet recording device, various deposition methods such as a pressure vibration type, an electrostatic acceleration type, and a pressure pulse type have been developed. There are no particular restrictions on the method, type of ink liquid, etc. as long as the liquid can be made to fly in the form of minute droplets or mist and reach a predetermined position on the recording medium. However, as the coloring dye in the ink liquid used, water-soluble direct dyes, acid dyes, basic dyes, etc. are generally suitable for use.

When an ink-receiving layer of thermoplastic organic polymer fine particles is provided on a support and characters or images are recorded on the ink-receiving layer with an inkjet recording device, the ink-receiving layer has many voids. The image is bright white and opaque.

In the present invention, the step of applying a solvent for the thermoplastic organic polymer to the ink-receiving layer that holds the inkjet recorded image, thereby dissolving and welding the thermoplastic organic polymer fine particles to form a film and converting it into a transparent layer is carried out. is necessary.

A method for applying a solvent to the ink-receiving layer is to directly apply the solvent to the ink-receiving layer after inkjet recording.
It can be applied by spraying, by immersion in an R8 medium bath, or by spraying a solvent from a specially provided nozzle during or after inkjet recording. There are methods such as attaching a solvent to the affected area.

When a solvent is applied, the thermoplastic organic polymer fine particles in the ink-receiving layer are dissolved, forming a transparent film while dragging the inkjet recorded image.

The solvent may then be removed and the coating identified.

The solvent 'fcVfs can be removed by completely vaporizing the solvent and then absorbing it into a support. At this time, it is effective to use auxiliary means such as heating, depressurization, and blowing air to reach the goal faster. Furthermore, by applying a mirror surface, a rough surface, a surface carved with a special pattern, pressing it against a roll, or applying light pressure, it is also possible to give the surface of the molten resin a desired luster and unevenness.

Historically, containing ultraviolet absorbers, anti-oxidizing agents, mold release agents, stabilizers, etc., which are usually used in thermoplastic resins, in the ink-receiving layer or adding them together with solvents has been known to improve the formed thermoplastic resin. It is desirable to prevent deterioration of the warm polymer film and further improve the weather resistance of dyes in inkjet images.

The term "solvent" as used in the present invention refers to an organic solvent that dissolves the water-insoluble thermoplastic organic polymer fine particles used in the present invention and has the effect of making at least their surfaces fluid and adhering to each other, thereby reducing the interface between them. . Typical examples include aliphatic hydrocarbons such as gasoline, benzine, and petroleum naphtha, aromatic hydrocarbons such as benzene, toluene, and xylene, trichlorethylene, perchlorethylene, chloroform, carbon tetrachloride, ethylene trichloride, - 7-logenated hydrocarbons such as benzene bromide and benzene dichloride, alcohols such as amyl alcohol, inglobil alcohol, 2-ethylhexyl alcohol, fuclohexanol, methylamyl alcohol, benzyl alcohol, butyl alcohol, acetone, acetyl alcohol, etc. Ketones such as nyl acetone, diisobutyl ketone, diethyl ketone, methyl amyl ketone, methyl butyl ketone, methyl cyclohexanone, methyl ethyl ketone, methyl in butyl ketone, methyl propyl ketone, medicyl oxide, acid esters, butyric acid esters alcohol esters such as propionate esters, 41st class esters, butyl lactate, isoprobyl lactate, porous ethyl oxyglopionate, diethyl maleate, and ketone esters such as ethyl acetoacetate and ethyl pyruvate. ethers such as inglovir ether, ethyl ether, ethyl carchtol, diethyl cellosolve, butyl ether, ketone alcohols such as acetonyl methanonyl, diacetone alcohol, dihydroxydylacetone, pyruvyl alcohol, inglovir cello Ether alcohols such as sorp, carbitol, glycidol, cellosolve, glycol ether, pensol cellosol, butyl carbitol, butyl cellosolve, methyl carbitol, methyl selon rub, triethylene glycol monoethyl ether, acetal ethyl ether, acetonyl Ketone ethers such as methanol ethyl ether, methyl ethoxyethyl ether, ester ethers such as butyl carbitol acetate, butyl cellosolve acetate, carbitol acetate, cellosolve acetate, 3-methoxybutyl acetate, methyl carbitol acetate, methyl cellosolve acetate, etc. be. Alternatively, a mixture of these can be used as a solvent, and it is also effective to use a mixture when it is necessary to adjust the drying rate, etc.

After inkjet recording on the ink-receiving layer made of thermoplastic organic polymer fine particles and adhesive formed on the support, the recording medium is subjected to dissolution treatment by applying a solvent.
A transparent and glossy inkjet image medium with excellent recorded image clarity, color reproducibility, and color density, and excellent water resistance and light resistance can be obtained.

In the present invention, in the case of using a transparent polymer film as a support, an inkjet image can be obtained as a totally transparent film-like recording medium, and therefore it is suitable as an original for an overhead projector.

In addition, if the support is coated paper coated with a white pigment, synthetic paper made of synthetic paper, baryta paper, resin coated paper, or other high-quality printing paper, or photographic support f, rL41, the inkjet image will be printed on an opaque support. Shiny skin +16! It is excellent as a recording medium that provides high-gloss images with excellent color reproducibility, color density, and resolution.

Furthermore, if you use a support that has a surface such as silky or fine-grained that is known in the photographic industry, you can obtain a surface equivalent to that, and when forming the entire ink-receiving layer, the covering surface By press-bonding the inkjet image, it is possible to obtain an inkjet recorded image with a corresponding patterned surface.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, parts and parts shown in Examples mean parts by weight and weight %.

Example 1 A 75 μm polyester film subjected to corona treatment was
Polyvinyl alcohol (Kuraray fiPV) as adhesive
A117) 5 parts, L- as thermoplastic organic polymer fine particles
A paint consisting of 50 parts of 8801 (polystyrene plastic pigment made by Asahi Dow) and 95 parts of water was mixed with a solid content of 15 g/
I applied it so that it was silent and let it dry. After recording an image using this as a recording medium with an inkjet device, m-xylene was sprayed onto it and air-dried. The ink receiving layer became a transparent film.

The inkjet image formed on the transparent film was clear and had high resolution, and was sufficiently satisfactory as an original for an overhead glossier.

Example 2 A transparent polyethylene layer was provided on the back side of base paper, and a titanium-containing polyethylene layer was provided on the surface ~ Styrene-butadiene copolymer latex 2 was applied as an adhesive to a photographic support.
LYTRON as thermoplastic organic polymer fine particles
A paint consisting of 50 parts of RX-1259 (Polystyrene Glastic Pigment manufactured by Monsanto) and 98 parts of water was applied to a solid content of 202/R and dried in a hot air dryer at 105°C. This was used as a recording medium for recording the entire image using an inkjet device, and then immersed in a toluene bath for 3 seconds, taken up, and air-dried.

The inkjet images formed on the support were clear and high resolution, resulting in a recording medium similar to glossy photographic paper, with high color density and a highly glossy surface.

Table 1 shows the measured color density values before and after treatment.

Table 1

Claims (1)

[Claims] 1. In a recording medium having an ink-receiving layer made of thermoplastic organic polymer fine particles and an adhesive and a gold film on a support, an organic solvent is applied to the ink-receiving layer after inkjet recording to remove the thermoplastic organic A method for processing a recording medium, characterized by dissolving and forming polymer fine particles into a film.