JP2003211651A - Method and apparatus for inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording method which feature a base material feeling and an image quality with the use of ink for inkjet recording which can be reacted and set by applying radioactive rays such as a visible light, ultraviolet rays or electron beams, and an inkjet recorder therefor. <P>SOLUTION: According to the inkjet recording method, after an ink of a type set by radioactive rays is jetted to a recording material face, an energy amount of radioactive rays for setting the hit ink is controlled, thereby adjusting a glossiness of an imaging part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method and a recording apparatus using an inkjet recording ink capable of reacting and curing by being irradiated with radiation such as visible light, ultraviolet rays, and electron beams, and particularly, at high resolution. The present invention relates to an inkjet technology capable of printing an image having no blurring and good fixing properties.

[0002]

2. Description of the Related Art In recent years, the inkjet recording method has been simple and easy.
Since it is possible to create images at low cost, it has been applied to various printing fields such as photography, various printing, marking, and special printing such as color filters. In particular, a recording device that emits and controls fine dots, ink that has improved color reproduction range, durability, and emission suitability, and special paper that has dramatically improved ink absorbency, coloring material coloring, surface gloss, etc. It is also possible to obtain an image quality comparable to that of a silver halide photograph by using. Improving the image quality of today's inkjet recording system is achieved by recording devices, ink,
It was achieved only when all the special paper was prepared.

On the other hand, flexible packaging is printed by a gravure printing method or a flexo printing method. Gravure printing and flexographic printing are being made at low cost and with short delivery due to devising manufacturing methods, but it takes a lot of time and cost to make a printing plate, and it takes time to stabilize the density after printing starts. In the case of samples (prototypes, exhibitions, limited sales items, etc.), a large amount of loss will occur and the unit price will be high. In addition, recently, there are some products that can be prepared as samples for flexible packaging films by the wet electrophotographic method, but it takes time to adjust the level at the time of startup and there is a problem in the durability of the printed image, so it efficiently corresponds to small lots. Not something you can do. Inkjet recording methods for flexible packaging are generally used to record the date of manufacture, expiration date, etc. in black or white after packaging is completed, but images such as letters, design images and photographs are recorded directly. Things are not common.

[0004] In recent packaging, in order to bring out the concept and features of the product, various contrivances have been made such as using a mat packaging material, making a part of the mat base material a glossy surface, or vice versa. There is. Furthermore, the required quality is increasing year by year, such as high image quality and no discomfort to the touch.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its objects are visible light, ultraviolet rays,
To provide an inkjet recording method and an inkjet recording apparatus having a characteristic of a texture of a base material and image quality in a technique using an inkjet recording ink capable of reacting and curing by being irradiated with radiation such as an electron beam. is there.

[0006]

The above objects of the present invention have been achieved by the following constitutions.

1. An inkjet recording method characterized in that after the radiation-curable ink is ejected onto the surface of the recording material, the glossiness of the image forming portion is adjusted by controlling the amount of energy of the radiation that cures the ink that has landed.

2. An inkjet recording method characterized in that the glossiness of an image forming portion is adjusted by controlling the time until the radiation which cures the landed ink is irradiated after the radiation curable ink is ejected onto the surface of the recording material.

3. 3. The inkjet recording method according to 1 or 2, wherein the glossiness is adjusted only in a predetermined image area.

4. The radiation-curable ink has a viscosity at 25 ° C. of 35 to 500 mPa · s. 5. The inkjet recording method described in any one of 1 to 3 above.

5. 5. The ink jet recording method according to any one of 1 to 4 above, wherein the base material of the recording material is non-ink-absorbing.

6. The maximum print thickness of the image forming section is 5
6. The ink jet recording method as described in any one of 1 to 5 above, wherein

7. 7. The inkjet recording method according to any one of 1 to 6 above, wherein the recording material is a printing plate material having a porous hydrophilic property on a substrate.

8. 8. The inkjet recording method according to the above 7, wherein the recording material has a porous hydrophilic layer, and 91% by mass or more of the material constituting the porous hydrophilic layer does not contain carbon atoms.

9. 9. The ink jet recording method as described in 8 above, wherein the material containing carbon atoms in the porous hydrophilic layer contains a saccharide.

10. An inkjet recording apparatus, wherein the inkjet recording method according to any one of 1 to 9 can be adopted to adjust the glossiness of an image forming portion.

As a result of various studies on the above-mentioned problems, the present inventors have shown that after the ink jet recording, radiation curable by irradiation with lower energy than that of the conventional one shows sufficient curability, and the formed image has high resolution. The present inventors have found that it is best to control the amount of energy of radiation or the time until the radiation is applied in order to obtain a desired glossiness using the mold ink.

The present invention will be described in more detail below. (1) Inkjet recording method First, the inkjet recording method of the present invention will be described.

In the present invention, the glossiness of the image forming portion is measured by a 60-degree specular glossiness according to JIS-Z-8741. For the measurement, for example, manufactured by Nippon Denshoku Industries Co., Ltd.
A gonio gloss meter (VGS-1001DP) is used.

Further, there is a method of generally using a pressure bonding roller for controlling the glossiness of the surface of the image forming portion, but it is necessary to use a pressure bonding roller having various surface roughness for arbitrarily controlling the glossiness. However, it is not realistic to adjust the gloss for each substrate. Partial crimping is required to change the glossiness partially, which is troublesome.

Therefore, the present invention employs a method of forming an image by an ink jet system using a radiation curable ink for adjusting the glossiness, and a radiation intensity (radiation energy amount) for curing the landing ink, This is addressed by controlling the time from the landing of ink on the recording medium to the irradiation of radiation.

If this method is adopted, even if it is desired to partially change the gloss of a predetermined image area, that is, the image forming portion, it can be easily made possible by controlling the above-mentioned radiation irradiation method only for that portion. .

Radiation irradiation includes ultraviolet rays, electron beams, X
It is possible to use various radiation sources such as radiation, visible light, and infrared light, but ultraviolet rays are preferable in consideration of curability, cost of radiation source, and the like. As the ultraviolet ray source, a mercury lamp, a metal halide lamp, an excimer lamp, an ultraviolet laser / LED, or the like can be used.

The basic irradiation method is disclosed in JP-A-60-132.
No. 767. According to this, the light source is provided on both sides of the head unit, and the head and the light source are scanned by the shuttle method. Irradiation is performed after a certain time has elapsed after the ink has landed. Further, curing is completed by another light source that is not driven. WO9,954,415 discloses, as an irradiation method, a method using an optical fiber and a method of irradiating a recording section with UV light by applying a collimated light source to a mirror surface provided on the side surface of the head unit.

At this time, it is preferable in adjusting the glossiness that the radiation irradiation is performed twice or more. Particularly, it is preferable to perform the first exposure with the LED or LD mounted on the head and to use the mercury lamp, the metal halide lamp, the flash light source, the fluorescent lamp and the like for the second and subsequent exposures.

In the method of exposing from the back surface of the head, the ink immediately after landing can be rapidly irradiated without using an optical fiber or an expensive optical system. Further, since the irradiation is from the back surface of the head, there is also an effect of preventing ink curing at the nozzle interface due to the reflection line from the recording material. The radiation source preferably has a projection shape on the recording material in the form of a band having a recording width for one scanning.

Specifically, a strip-shaped metal halide lamp tube and an ultraviolet lamp tube are preferable. The radiation source can be made inexpensive by substantially fixing it to the recording device and eliminating the movable part.

In any of the exposure methods, it is one of the preferable modes that two kinds of radiation sources are prepared and the curing is completed by the second radiation source. This contributes to obtaining the wettability of the second color landing ink and the adhesiveness between the inks, and to assemble the radiation source at low cost.

It is preferable that the first radiation source and the second radiation source have different exposure wavelengths or exposure illuminances. The first irradiation energy is smaller than the second irradiation energy, that is, the first irradiation energy is 1 to 20 of the total irradiation energy.
%, Preferably 1 to 10%, more preferably 1 to 5%. By performing irradiation with different illuminance, the molecular weight distribution after curing becomes preferable. That is, when irradiation with high illuminance is performed at one time, the polymerization rate is increased, but the molecular weight of the polymerized polymer is small, and strength cannot be obtained. For compositions with extremely low viscosity, such as inkjet ink,
A remarkable effect is obtained.

Further, by setting the wavelength of the first irradiation to be longer than that of the second irradiation, the surface layer of the ink is hardened by the first irradiation to suppress the ink bleeding, and the radiation is hard to reach by the second irradiation. It is possible to cure the ink near the recording material and improve the adhesion. In order to accelerate the curing inside the ink, the second
The radiation wavelength of is preferably long wavelength.

The ink jet recording method of the present invention is characterized in that a radiation curable ink is used and the time from the impact to the second irradiation is shortened to reduce the gloss, and the time from the impact to the irradiation is lengthened. Can be raised.
The first irradiation is 0.01 to 0.5 seconds, preferably 0.0.
Irradiation is performed after 1 to 0.3 seconds, more preferably 0.01 to 0.15 seconds. The time until the second irradiation is preferably about 0.5 seconds to 3 minutes. In this way, by controlling the time from landing to irradiation to an extremely short time, it becomes possible to prevent the landing ink from bleeding before curing.
In addition, since it is possible to expose the porous recording material before the ink penetrates to a deep portion where the light source does not reach, residual unreacted monomer can be suppressed and odor can be reduced. This brings about a great synergistic effect by using the radiation curable ink. In particular, a great effect can be obtained by using an ink having an ink viscosity at 25 ° C. of 35 to 500 mPa · s.

By adopting such a recording method, the dot diameter of the landed ink can be kept constant even on various recording materials having different surface wettability, and the image quality is improved. In order to obtain a color image, it is preferable to superimpose colors in order of low lightness. When inks of low lightness are piled up, the radiation does not easily reach the lower inks, so that the curing sensitivity is impaired, the amount of residual monomer increases, the odor is generated, and the adhesiveness is easily deteriorated. In addition, it is possible to irradiate all colors and expose them collectively, but it is preferable to expose each color one by one from the viewpoint of curing acceleration.

In the present invention, it is preferable that the base material of the recording material is non-ink absorbing. Here, "ink non-absorptive" means that a fibrous material such as paper is used to absorb ink, or a resin that absorbs and swells ink is used as an ink absorbing layer on a film, or filler or resin particles are used. It means that it does not have an ink absorption layer in which voids are provided in the layer. Specifically, those generally used as a soft packaging material are preferable. As the material of the soft packaging material, polyester, polyolefin, polyamide, polyesteramide, polyether, polyimide, polyamideimide, polystyrene, polycarbonate, poly-p-phenylene sulfide, polyether ester, polyvinyl chloride, poly (meth) acrylic acid Ester, polyethylene, polypropylene and nylon are preferred. Further, these copolymers and blends, and further crosslinked products can be used. Among them, stretched polyethylene terephthalate, polystyrene, polypropylene and nylon are preferable in terms of transparency, dimensional stability, rigidity, environmental load and cost. The thickness of the film is 2 to 100 μm, preferably 6 to
It is 45 μm, more preferably 10 to 30 μm.

In order to adjust the adhesive strength with the layer to be formed and to obtain good coating properties, it is preferable to subject the surface of the substrate to a surface treatment such as corona discharge treatment or easy adhesion treatment.

The maximum print thickness of the image forming portion is 5 to 6
0 μm is preferable. When it is thicker than 60 μm, the user feels uncomfortable when holding the base material, or the image portion becomes large when touched, and the texture of the base material cannot be utilized. Alternatively, the adhesiveness with the base material deteriorates. Also, 5 μm
If it is less than the above range, the light color is not a problem, but the stability of the density becomes low in the middle to high density portions, the image defect on the streak is likely to occur, and the graininess deteriorates and the image quality deteriorates.
Further, stickiness and ink scratchability may be deteriorated in the low density portion. The maximum portion of the print film thickness of the image forming portion is preferably 10 to 45 μm, more preferably 10 to 30 μm.

In the ink jet recording method of the present invention, it is preferable from the viewpoint of ejection stability that the radiation curable ink is heated to 40 to 80 ° C. to reduce the viscosity of the ink before ejection. Since the radiation-curable ink generally has a higher viscosity than the water-based ink, the fluctuation range of viscosity due to temperature fluctuation is large. The viscosity fluctuation directly affects the droplet size and droplet ejection speed,
Since the image quality deteriorates, it is necessary to keep the ink temperature as constant as possible. Ink temperature control range is set temperature ±
The temperature is 5 ° C, preferably ± 2 ° C, and more preferably ± 1 ° C. (2) Inkjet recording device The inkjet recording device is provided with a means for stabilizing the ink temperature, but the part that keeps the temperature constant is the piping system from the ink tank (if there is an intermediate tank) to the nozzle ejection surface All are covered. In order to control the temperature, it is preferable to provide a plurality of temperature sensors at each piping site and control heating according to the ink flow rate and the environmental temperature.
Further, it is preferable that the head unit to be heated is thermally shielded or insulated so as not to be affected by the temperature from the apparatus body and the outside air. In order to shorten the start-up time of the recording apparatus required for heating and to reduce the loss of heat energy, it is preferable to perform heat insulation from other parts and reduce the heat capacity of the entire heating unit.

The head unit is composed of an ink jet nozzle head, an ink liquid supply system, a temperature control mechanism for ink and head, a control board and the like. When irradiating light from the back surface, it is preferable that the head unit has a projection area on the recording material as small as possible. The smaller the projected area on the recording material, the more effectively the first irradiation is utilized.

Further, in a unit composed of heads of a plurality of colors, it is preferable that the spaces between the colors are substantially transparent to radiation. Specifically, the heads are made of a radiation-transmissive member, or the members are not arranged. In the present invention, with such a simple structure, it is possible to immediately irradiate each color immediately after landing, and especially to prevent bleeding of secondary colors and dot bleeding on the way back and forth in bidirectional drawing. It is preferable because it can prevent the difference (prevent the difference between the going and returning colors).

The radiation according to the present invention is not particularly limited as long as it cures the radiation curable ink, and specific examples thereof include ultraviolet rays (UV), electron beams and heat.

In the irradiation of ultraviolet rays, heat is likely to be generated and the recording medium may be deformed. Therefore, it is preferable to provide a cooling mechanism such as a cold mirror, a cold filter and a work cooling. . The types of lamps used for ultraviolet irradiation include high pressure mercury lamps, ultra high pressure mercury lamps, and metal halides.

The ultra-high pressure mercury lamp is a point light source, but the DeepUV type, which has a high light utilization efficiency in combination with an optical system, can irradiate in a short wavelength region. Metal halides have a wide wavelength range and are effective for colored products. Pb, S
Halides of metals such as n and Fe are used and can be selected according to the absorption spectrum of the photoinitiator. Any lamp that is effective for curing can be used without particular limitation.

From the viewpoint of obtaining the effects of the present invention, low energy radiation is preferable, but specifically, the amount of energy applied during radiation is preferably 400 mJ / cm ² or less, more preferably 300 mJ / cm ^2. c
m ² or less, particularly preferably 50 to 300 mJ / c
m ² .

In the present invention, as the radiation curable ink, white ink may be used in addition to commonly used yellow, magenta, cyan and black and, if necessary, light-colored inks.

When the white ink is used, the nozzle diameter of the ink jet head is larger for the ink containing the white pigment than for the ink containing the coloring material other than the white ink, or the number of nozzles or heads is larger. Is preferable. Above all, it is preferable to increase the nozzle diameter. It is preferably 1.2 to 50 times. When the nozzle diameter of the head for white pigment-containing ink is the same as or smaller than that of ink containing color materials other than white, the density of white becomes low and a clear image cannot be obtained, or white is ejected at high density. As a result, the recording speed becomes slow, and the frequency of image defects due to nozzle clogging becomes high. The nozzle diameter of the pigment head containing the ink color material other than white is 10 to 40.
μm is preferred. More preferably, it is 15 to 35 μm. If the nozzle diameter is too small, image defects due to clogging of ink may occur, or the ejection speed of ink may decrease, causing image unevenness. If the nozzle diameter is too large, high-resolution injection cannot be stably performed. (Radiation-curable ink) Radiation-curable ink is described in, for example, JP-A-8-218017 and JP-A-2000-117.
Conventionally known water-based radiation-curable inkjet inks described in 960 and the like can be used.

The first ink material composition is a composition comprising a pigment or dye as a coloring material, water, a liquid water-soluble polymerizable compound and a water-soluble photopolymerization initiator.

The second ink material composition is a composition comprising a pigment or dye as a coloring material, water, a water-soluble organic solvent, a liquid water-soluble polymerizable compound and a water-soluble photopolymerization initiator.

The third ink material composition is a pigment or dye as a coloring material, water, a water-insoluble polymerizable compound and a photopolymerization initiator,
A composition composed of an organic solvent that dissolves the water-insoluble polymerizable compound and an initiator. In addition, the so-called VOC (Volati) obtained by removing water and an organic solvent from the ink material composition is used.
An ink called a radiation-curable ink free of le Organic Compound or an oil-based radiation-curable ink is also preferably used.

As an ink material having still another constitution, the heat-meltable radiation-curable inks described in JP-A-6-200204 and JP-A-11-256085 can be preferably used. In addition to the above radical polymerization type ink, for example, the cationic polymerization type ink described in JP-A-10-324836 can also be preferably used.

The radiation-curable ink used in the present invention comprises at least a polymerizable monomer and an initiator.

Various (meth) acrylate monomers can be used as the polymerizable monomer. For example, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isomystil acrylate, isostearyl acrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethyl hexahydrophthalic acid. , Butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate,
Methoxy polyethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl-2
-Hydroxyethyl-phthalic acid, lactone-modified flexible acrylate, monofunctional monomers such as t-butylcyclohexyl acrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol Diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9
Nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, EO adduct diacrylate of bisphenol A, PO adduct diacrylate of bisphenol A, neopentyl glycol diacrylate hydroxypivalate, polytetramethylene Bifunctional monomers such as glycol diacrylate, trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, pentaerythritol triacrylate,
Trifunctional or more than pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, glycerin propoxy triacrylate, cowprolactone modified trimethylolpropane triacrylate, pentaerythritol ethoxy tetraacrylate, caprolactam modified dipentaerythritol hexaacrylate, etc. The polyfunctional monomer of is mentioned.

In addition, polymerizable oligomers can be blended in the same manner as the monomers. Examples of the polymerizable oligomer include epoxy acrylate, aliphatic urethane acrylate, aromatic urethane acrylate, polyester acrylate, and linear acrylic oligomer.

In the present invention, it is particularly preferable to use a monofunctional, difunctional, trifunctional or higher polyfunctional monomer in combination as the polymerizable monomer. The monofunctional monomer has a large effect of reducing the shrinkage rate at the time of curing, has a low viscosity, and can easily obtain injection stability at the time of inkjet recording. The bifunctional monomer is preferably added because it has an appropriate sensitivity and excellent adhesion to various supports. A trifunctional or higher polyfunctional monomer provides sensitivity and film strength after curing. By using these three together, curling and waviness due to curing shrinkage can be prevented, adhesion to a support and high sensitivity can be achieved.

The monofunctional monomer accounts for 5 to 5 parts of the total ink composition.
40% by mass, 5 to 40% by mass of the bifunctional monomer, and 5 to 30% by mass of the polyfunctional monomer are preferably contained.
The monomer used in combination has a solubility parameter (SP
The combination of the difference between the maximum and minimum values is 1 or more,
It is preferable in terms of adhesion to various base materials and prevention of curling due to curing shrinkage. More preferably, it is 1.5 or more.

From the viewpoint of safety such as sensitization, skin irritation, eye irritation, mutagenicity and toxicity, among the above-mentioned monomers, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate,
Decyl acrylate, isomyrsyl acrylate, isostearyl acrylate, ethoxydiethylene glycol acrylate, methoxy polyethylene glycol acrylate, methoxypropylene glycol acrylate, isobornyl acrylate, lactone modified flexible acrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene Glycol diacrylate, EO-modified trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, glycerin propoxytriacrylate, cowprolactone-modified trimethylolpropane triacrylate, pentaerythritol ethoxytetraacrylate, capro Kutamu modified dipentaerythritol hexaacrylate are preferable.

Further, among these, stearyl acrylate, lauryl acrylate, isostearyl acrylate, ethoxydiethylene glycol acrylate, isobornyl acrylate, tetraethylene glycol diacrylate, EO-modified trimethylolpropane triacrylate, glycerin propoxytriacrylate, cowprolactone-modified tri Methylolpropane triacrylate and caprolactam-modified dipentaerythritol hexaacrylate are particularly preferable initiators as arylalkyl ketone, oxime ketone, and thiobenzoic acid S.
Conventionally known initiators such as -phenyl, titanocene, aromatic ketone, thioxanthone, benzyl and quinone derivatives and ketocoumarins can be used. For the initiator, see "UV
・ Application and market of EB curing technology ”(CMC Publishing, supervised by Yoneho Tabata / edited by Radtech Study Group). Among them, acyl phosphine oxide and acyl phosphonate have high sensitivity and their absorption is reduced by photocleavage of the initiator.
It is particularly effective for internal curing in an ink image having a thickness of m. Specifically, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,2
6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide and the like are preferable.

Further, like the above-mentioned monomers, 1-hydroxy-cyclohexyl-phenyl-ketone and 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane-1 were selected in consideration of safety. -One, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur (R) 1173) Is preferably used. The preferable addition amount is 1 to 6% by mass, and preferably 2 to 5% by mass of the whole ink composition. In the present invention, it is preferable to divide the irradiation into two stages by changing the wavelength or intensity, and it is particularly preferable to use two or more kinds of initiators together.

In addition to this, when coloring the ink composition,
Add colorant. As the coloring material, a coloring material that can be dissolved or dispersed in the main component of the polymerizable compound can be used, but a pigment is preferable from the viewpoint of weather resistance.

The following can be used as the pigment,
It is not limited to this. C. I Pigment Yellow-1,3,1
2, 13, 14, 17, 81, 83, 87, 95, 10
9, 42, C.I. I Pigment Orange-16, 36,
38, C.I. I Pigment Red-5, 22, 38, 4
8: 1, 48: 2, 48: 4, 49: 1, 53: 1, 5
7: 1, 63: 1, 144, 146, 185, 101, C.I. I Pigment Violet-19, 23, C.I. I Pigment Blue-15: 1, 15:
3,15: 4,18,60,27,29, C.I. I Pigment Green-7, 36, C.I. I Pigment White-6, 18, 2
1, C.I. The dispersion of the I Pigment Black-7 pigment preferably has an average particle diameter of 0.08 to 0.5 μm, and the maximum particle diameter is 0.3 to 10 μm, preferably 0.3 to 3 μm. Select agents, dispersion media, dispersion conditions, and filtration conditions. By controlling the particle size, clogging of the head nozzle can be suppressed, and the ink storage stability, ink transparency, and curing sensitivity can be maintained. The color material is preferably added in an amount of 1 to 10% by mass of the entire ink. (Other components) In order to enhance the storability of the ink composition,
A polymerization inhibitor can be added in an amount of 200 to 20000 ppm. Since it is preferable that the ultraviolet curable ink is heated to lower the viscosity and then ejected, it is preferable to add a polymerization inhibitor in order to prevent head clogging due to thermal polymerization.

In addition to these, a surfactant, a leveling additive, a matting agent, a polyester resin, a polyurethane resin, a vinyl resin, an acrylic resin, a rubber resin, a wax for adjusting the physical properties of the film, if necessary. Can be added.

In order to improve the adhesiveness with the recording material, it is also effective to add an extremely small amount of organic solvent. In this case, it is effective to add it within a range that does not cause problems of solvent resistance and VOC, and the amount is 0.1 to 5%, preferably 0.1 to 3%.
%.

Further, because of the light-shielding effect of the ink coloring material, as a means for preventing sensitivity, it is also possible to combine a cationically polymerizable monomer having a long initiator life with an initiator to prepare a radical / cation hybrid type curable ink. .

The ink is preferably 7 to 30 mPa · s, more preferably 7 to 30 mPa · s in temperature at the time of ejection in consideration of ejectability.
The composition ratio is determined so as to be ˜20 mPa · s. 2
The ink viscosity at 5 ° C is 35 to 500 mPa · s, and further 3
It is preferably 5 to 200 mPa · s. By increasing the viscosity at room temperature, it is possible to prevent ink from penetrating into porous recording materials, reduce uncured monomer and odor, and prevent dot bleeding when landing, improving image quality. It If it is less than 35 mPa · s, the effect of preventing bleeding is small. If it is larger than 500 mPa · s, a problem occurs in the delivery of the ink liquid.

The surface tension is preferably 200 to 300 μN.
/ Cm, and more preferably 230 to 280 μN / cm. When recording on various recording materials such as olefin, PET, coated paper, and uncoated paper, it is 200 in terms of bleeding and penetration.
μN / cm or more is preferable, and in view of wettability, 300 μN / cm
cm or less is preferable.

Further, as the recording material in the present invention, a printing plate material having porosity and hydrophilicity on the substrate is preferable. Specifically, the printing plate material is a printing plate material having a porous hydrophilic layer and 91% by mass or more of the material constituting the hydrophilic layer is a material containing no carbon atom. Further, it is preferable that 95% by mass or more is a material containing no carbon atoms.

The "material containing no carbon atom" as used herein refers to a material excluding the organic group portion of an organic substance or a compound having an organic group, carbon black, graphite, etc., and "the mass of the material containing no carbon atom". "%" Means the mass ratio of the whole layer excluding the organic group and the organic group portion of the compound having the organic group, carbon black, graphite and the like. For materials that are surface-treated with materials containing carbon atoms that do not contain carbon atoms, only the materials used for the treatment are regarded as materials containing carbon atoms.

The above is the material constitution at the time when it is formed as a hydrophilic layer. For example, even if it is contained in the coating liquid for the hydrophilic layer, a material that volatilizes when dried is not included. Further, the material in which the porous inner pores are impregnated from the outside after the hydrophilic layer is formed is not included.

91% by mass or more of inorganic material, preferably 9
When the content is 5% by mass or more, quick printing can be obtained,
The blanket stain is also reduced, and good printing performance such as no background stain when printing is obtained.

The metal oxide-free material used for the hydrophilic layer of the printing plate material is preferably a metal oxide.

The metal oxide preferably contains fine metal oxide particles. Examples thereof include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The form of the metal oxide fine particles may be spherical, needle-like, feather-like, or any other form. The average particle size is preferably 3 to 100 nm,
It is also possible to jointly use several kinds of metal oxide fine particles having different average particle diameters. Further, the surface of the particles may be surface-treated.

The metal oxide fine particles can be used as a binder by utilizing the film forming property thereof. It has less decrease in hydrophilicity than using an organic binder and is suitable for use in a hydrophilic layer.

In the present invention, colloidal silica is particularly preferably used among the above. Colloidal silica has an advantage that it has a high film-forming property even under a drying condition at a relatively low temperature, and can obtain good strength even in a layer containing 91% by mass or more of a material containing no carbon atom.

The colloidal silica preferably includes a necklace-shaped colloidal silica described later and fine particle colloidal silica having an average particle size of 20 nm or less. Further, the colloidal silica preferably exhibits alkalinity as a colloidal solution.

The necklace-shaped colloidal silica used in the present invention is a general term for an aqueous dispersion system of spherical silica having a primary particle size of the order of nm. The necklace-shaped colloidal silica used in the present invention has a primary particle size of 10 to 50.
It means a "pearl necklace-like" colloidal silica in which spherical spherical colloidal silica having a diameter of 50 nm is bonded to a length of 50 to 400 nm. The pearl necklace shape (that is, a pearl necklace shape) means that the image of the silica particles of colloidal silica connected in series is like a pearl necklace. The silica particles forming the necklace-shaped colloidal silica are bonded to each other by -Si-O- which is formed by dehydration bonding of -SiOH groups existing on the surface of the silica particles.
It is estimated to be Si-. Specific examples of the necklace-shaped colloidal silica include "Snowtex-PS" series manufactured by Nissan Chemical Industries, Ltd.

The product name is "Snowtex-PS-
S (average particle size in a connected state is about 110 nm) ",
"Snowtex-PS-M (average particle size in a connected state is about 120 nm)" and "Snowtex-PS-
L (average particle size in a connected state is about 170 nm) ", and acidic products corresponding to these are" Snowtex-PS-S-O "and" Snowtex-PS-O ".
"MO" and "Snowtex-PS-LO".

By adding the necklace-shaped colloidal silica, it becomes possible to maintain the strength of the layer while ensuring the porosity of the layer, and it can be preferably used as a material for making the layer porous.

Among these, "Snowtex PS-S", "Snowtex PS-M", which are alkaline,
Use of "Snowtex PS-L" is particularly preferable because the strength of the hydrophilic layer is improved and the occurrence of background stain is suppressed even when the number of printed sheets is large.

It is known that the smaller the particle size of colloidal silica, the stronger the binding force. In the present invention, it is preferable to use colloidal silica having an average particle size of 20 nm or less, preferably 3 to 15 nm. More preferably. Further, as described above, among colloidal silicas, alkaline ones are highly effective in suppressing the generation of background stains, so that it is particularly preferable to use alkaline colloidal silicas.

Alkaline colloidal silica having an average particle size in this range includes "Snowtex-20 (particle size 10 to 20 nm)", "Snowtex-30 (particle size 10 to 20 nm)" manufactured by Nissan Chemical Industries, Ltd., "Snowtex-40 (particle diameter 10 to 20 nm)", "Snowtex-N (particle diameter 10 to 20 nm)", "Snowtex-S (particle diameter 8 to 11 nm)", "Snowtex-X"
S (particle diameter 4 to 6 nm) ".

Colloidal silica having an average particle size of 20 nm or less is particularly preferable when it is used in combination with the above-mentioned necklace-shaped colloidal silica because the layer can be further improved in strength while maintaining its porosity.

The ratio of colloidal silica having an average particle size of 20 nm or less / necklace colloidal silica is 95 /
5/5/95 is preferable, 70 / 30-20 / 80 is more preferable, and 60 / 40-30 / 70 is further preferable.

The hydrophilic layer of the printing plate material contains porous metal oxide particles as the metal oxide. As the porous metal oxide particles, porous silica or porous aluminosilicate particles or zeolite particles described later can be preferably used. -Porous silica or porous aluminosilicate particles Porous silica particles are generally produced by a wet method or a dry method. The wet method can be obtained by drying and pulverizing a gel obtained by neutralizing an aqueous silicate solution, or pulverizing a precipitate precipitated by neutralization. The dry method is obtained by burning silicon tetrachloride with hydrogen and oxygen to precipitate silica. The porosity and particle size of these particles can be controlled by adjusting the production conditions. As the porous silica particles, those obtained from a wet method gel are particularly preferable.

The porous aluminosilicate particles are produced, for example, by the method described in JP-A-10-71764. That is, it is an amorphous composite particle composed mainly of aluminum alkoxide and silicon alkoxide synthesized by a hydrolysis method. The ratio of alumina to silica in the particles can be synthesized in the range of 1: 4 to 4: 1. Further, alkoxides of other metals added during the production to produce composite particles of three or more components can also be used in the present invention. The porosity and particle size of these composite particles can be controlled by adjusting the production conditions.

The porosity of the particles is preferably 1.0 ml / g or more in pore volume before dispersion.
It is more preferably 1.2 ml / g or more and 1.8
More preferably, it is not more than 2.5 ml / g.

The pore volume is closely related to the water retention property of the coating film. The larger the pore volume, the better the water retention property, the less likely it is to stain during printing, and the wider the water amount latitude.
If it exceeds 5 ml / g, the particles themselves become very brittle and the durability of the coating film decreases. Pore volume is 1.0 ml
If it is less than / g, the stain resistance during printing and the width of the water amount latitude are insufficient.

The particle diameter is preferably substantially 1 μm or less, and preferably 0.5 μm or less when contained in the hydrophilic layer (including, for example, when it is crushed during dispersion). More preferable. If unnecessarily coarse particles are present, porous and steep projections are formed on the surface of the hydrophilic layer, and ink is likely to remain around the projections, resulting in deterioration of non-image area stains and blanket stains. -Zeolite particles Zeolites are crystalline aluminosilicates,
It is a porous body having pores with a regular three-dimensional network structure having a pore size of 0.3 to 1 nm. The general formula for the combination of natural and synthetic zeolites is represented as:

[0086] (M¹, M² _0.5)_m(Al_mSi_nO_{2 (m + n)}) XH₂O Where M¹, M²Is an exchangeable cation, M¹Is
Li⁺, Na⁺, K⁺, Tl⁺, Me_FourN⁺(TMA), Et
_FourN⁺(TEA), Pr_FourN⁺(TPA), C₇H₁₅N₂ ⁺,
C₈H₁₆N⁺Etc. and M²Is Ca²⁺, Mg²⁺, Ba²⁺,
Sr²⁺, C₈H₁₈N ₂ ²⁺Etc. Also, n ≧ m, and m
The value of / n, that is, the Al / Si ratio is 1 or less. Al
The higher the / Si ratio, the higher the amount of exchangeable cations contained.
Therefore, it has high polarity and therefore high hydrophilicity. Preferred Al
/ Si ratio is 0.4 to 1.0, and more preferably
It is 0.8 to 1.0. x represents an integer.

The zeolite particles used in the present invention are preferably synthetic zeolites having a stable Al / Si ratio and a relatively sharp particle size distribution. For example, zeolite A: Na ₁₂ (Al ₁₂ Si ₁₂ O ₄₈ ) ・ 27H
₂ O; Al / Si ratio 1.0, zeolite X: Na
₈₆ (Al ₈₆ Si ₁₀₆ O ₃₈₄ ) ・ 264H ₂ O; Al / Si
Ratio 0.811, zeolite Y: Na ₅₆ (Al ₅₆ Si
₁₃₆ O ₃₈₄ ) ・ 250H ₂ O; Al / Si ratio 0.412
Etc.

By containing highly hydrophilic porous particles having an Al / Si ratio of 0.4 to 1.0, the hydrophilicity of the hydrophilic layer itself is greatly improved, stains are less likely to occur during printing, and the water amount latitude is wide. Become. In addition, stains on fingerprint marks are also greatly improved. When the Al / Si ratio is less than 0.4, the hydrophilicity is insufficient and the effect of improving the above performance becomes small.

The particle size of the porous inorganic particles, when contained in the hydrophilic layer, is preferably substantially 1 μm or less, more preferably 0.5 μm or less.

The hydrophilic layer of the printing plate material contains layered clay mineral particles as a metal oxide. Examples of the layered clay mineral particles include clay minerals such as kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, savonite), vermiculite, mica (mica), and chlorite, and hydrotalcite, layered polysilicate. (Kanemite, macatite,
Ialite, magadiite, Kenyaite, etc.) and the like. Above all, it is considered that the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The charge density is preferably 0.25 or more, more preferably 0.6 or more. Layered minerals having such a charge density include smectite (charge density of 0.25 to 0.25).
0.6; negative charge), vermiculite (charge density 0.6)
.About.0.9; negative charge) and the like. In particular, synthetic fluoromica is preferable since it can be obtained with stable quality such as particle size. Among the synthetic fluoromica, those which are swellable are preferable, and those which are free swelling are more preferable.

Further, intercalation compounds of the above-mentioned layered minerals (pillar crystals, etc.), those subjected to ion exchange treatment, and surface treatments (silane coupling treatment, composite treatment with organic binder, etc.) were conducted. Things can also be used.

Regarding the size of the plate-like layered clay mineral particles, the average particle size (maximum length of particles) in the state of being contained in the layer (including the case of undergoing the swelling step and the dispersion peeling step)
Is 20 μm or less, and the average aspect ratio (maximum length of particles / thickness of particles) is preferably 20 or more in a thin layer form. The average particle size is 5 μm or less and the average aspect ratio is 50 or more. More preferably, the average particle size is 1
More preferably, the average aspect ratio is 50 or more. When the particle size is in the above range,
The continuity in the plane direction and the flexibility, which are characteristics of the thin layered particles, are imparted to the coating film, and it is possible to obtain a coating film that is hard to crack and is tough in a dry state. Further, the coating liquid containing a large amount of particles can suppress the sedimentation of particles due to the thickening effect of the layered clay mineral. If the particle size is out of the above range, the effect of suppressing scratches due to scratching may be reduced. If the aspect ratio is less than the above range, the flexibility may be insufficient, and similarly the scratch-suppressing effect due to scratching may be reduced.

The content of the layered clay mineral particles is preferably 0.1 to 30 mass% of the entire layer, and 1 to 1
It is more preferably 0% by mass. In particular, swelling synthetic fluoromica and smectite are preferable because the effect can be seen even when added in a small amount. The layered clay mineral particles may be added as a powder to the coating solution, but in order to obtain a good dispersibility even with a simple preparation method (no need for a dispersion step such as media dispersion), the layered clay mineral particles are It is preferable to add the gel to the coating liquid after preparing a gel swollen with water by itself.

An aqueous solution of silicate can also be used as another additive material containing no carbon atom in the hydrophilic layer of the printing plate material. Alkali metal silicates such as Na silicate, K silicate and Li silicate are preferable, and their SiO ₂
/ M ₂ O ratio is p of the whole coating solution when silicate is added
It is preferable to select H so as not to exceed 13 in order to prevent dissolution of the inorganic particles.

Further, an inorganic polymer or an organic-inorganic hybrid polymer using a so-called sol-gel method using a metal alkoxide can also be used. The formation of the inorganic polymer or the organic-inorganic hybrid polymer by the sol-gel method is described, for example, in "Application of the sol-gel method" (Sakuo Sakuo / Agne Chofusha) or cited in this document. Known methods described in the literature can be used.

Among these, the silica coating film obtained by the sol-gel method using tetraalkoxysilane does not contain carbon atoms. However, when an alkoxysilane having an alkyl group, such as an alkoxytrialkoxysilane, is used, the alkyl group remains in the resulting silica coating film. In the present invention, the remaining alkyl group content is regarded as a material containing carbon atoms.

In the present invention, the material containing carbon atoms in the hydrophilic layer of the printing plate material is less than 9% by mass, preferably 5%.
It can be contained in less than mass%.

Examples of the material containing carbon atoms include polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PE
G), polyvinyl ether, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer conjugated diene polymer latex, acrylic polymer latex, vinyl polymer latex, polyacrylamide, polyvinylpyrrolidone, and other resins. To be

Further, a cationic resin may be contained, and as the cationic resin, polyalkylene polyamines such as polyethylene amine and polypropylene polyamine or derivatives thereof, tertiary amino group and quaternary ammonium group are included. The acrylic resin, diacrylamine, etc. which it has are mentioned. The cationic resin may be added in the form of fine particles. Examples thereof include cationic microgels described in JP-A-6-161101.

In a preferred embodiment of the present invention, the material containing carbon atoms contained in the hydrophilic layer is water-soluble, and at least a part of the material is in a water-soluble state and can be eluted in water. Can be mentioned in. If a water-soluble material is cross-linked by a cross-linking agent or the like and becomes insoluble in water, its hydrophilicity may be lowered and printing performance may be deteriorated.

The water-soluble material containing carbon atoms contained in the hydrophilic layer is preferably sugar. By containing a saccharide in the hydrophilic layer, the effect of improving the resolution of image formation and improving the printing durability can be obtained.

As the saccharide, an oligosaccharide which will be described in detail later can be used, but a polysaccharide is particularly preferably used.

As the polysaccharide, starch, cellulose, polyuronic acid, pullulan, etc. can be used.
Particularly, cellulose derivatives such as methyl cellulose salt, carboxymethyl cellulose salt and hydroxyethyl cellulose salt are preferable, and sodium salt and ammonium salt of carboxymethyl cellulose are more preferable.

This is because inclusion of the polysaccharide in the hydrophilic layer has an effect of forming the surface shape of the hydrophilic layer in a preferable state.

The surface of the hydrophilic layer preferably has a concavo-convex structure with a pitch of 0.1 to 50 μm like the aluminum grain of a PS plate, and this concavo-convex improves the water retention and the retention of the image area.

Such a concavo-convex structure can be formed by adding an appropriate amount of a filler having an appropriate particle size to the hydrophilic layer, but the hydrophilic colloidal silica and the aforementioned alkaline colloidal silica are added to the coating solution for the hydrophilic layer. It is preferable that the water-soluble polysaccharide is added to form a layer having phase separation when the hydrophilic layer is applied and dried, because a structure having better printing performance can be obtained.

The form of the concavo-convex structure (pitch, surface roughness, etc.) depends on the type and addition amount of alkaline colloidal silica,
It is possible to appropriately control the kind and addition amount of the water-soluble polysaccharide, the kind and addition amount of other additives, the solid content concentration of the coating liquid, the wet film thickness, the drying conditions and the like.

The pitch of the concavo-convex structure is 0.2 to 30 μm.
m is more preferable, and 0.5 to 20 μm is even more preferable. Further, a concavo-convex structure having a large pitch and a concavo-convex structure having a smaller pitch may be formed on the concavo-convex structure having a large pitch.

The surface roughness Ra is 100 to 100.
0 nm is preferable, and 150 to 600 nm is more preferable.

The film thickness of the hydrophilic layer is from 0.01 to
50 μm, preferably 0.2 to 10 μm,
More preferably, it is 0.5 to 3 μm.

Further, the hydrophilic layer (coating solution thereof) may contain a water-soluble surfactant for the purpose of improving the coatability. Although a Si-based or F-based surfactant can be used, it is particularly preferable to use a surfactant containing a Si element because there is no concern that print stains will occur. The content of the surfactant is preferably 0.01 to 3% by mass, and more preferably 0.03 to 1% by mass based on the entire hydrophilic layer (solid content as a coating liquid).

The hydrophilic layer can also contain a phosphate. In the present invention, it is preferable that the coating liquid for the hydrophilic layer is alkaline. Therefore, it is preferable to add trisodium phosphate or disodium hydrogen phosphate as the phosphate. By adding the phosphate, the effect of improving the mesh opening during printing can be obtained. The amount of phosphate added is preferably 0.1 to 5% by mass, and more preferably 0.5 to 2% by mass, as an effective amount excluding hydrate.

[0113]

The present invention will be described in more detail with reference to the following examples. The following "parts" represent "parts by mass".

Example 1 (Preparation of Pigment Dispersion) A pigment dispersion was prepared with the following composition. The average particle size was dispersed so as to be 0.2 to 0.3 μm. Yellow Pigment Dispersion 1 Pigment Yellow 12 10 parts Polymer Dispersant 5 parts Stearyl Acrylate 85 parts Magenta Pigment Dispersion 1 Pigment Red 57: 1 15 parts Polymer Dispersant 5 parts Stearyl Acrylate 80 parts Cyan Pigment Dispersion 1 Pigment Blue 15 : 3 20 parts Polymer dispersant 5 parts Stearyl acrylate 75 parts Black pigment dispersion 1 Pigment Black 7 20 parts Polymer dispersant 5 parts Stearyl acrylate 75 parts White pigment dispersion 1 Titanium oxide (anatase type: particle size 0.2 μm ) 20 parts Polymer dispersant 5 parts Stearyl acrylate 85 parts (Preparation of ink) Using the above dispersion, an ink having the following formulation was prepared. Yellow ink 1 Yellow pigment dispersion 1 20 parts Stearyl acrylate 60 parts Bifunctional aromatic urethane acrylate (molecular weight 1500) 10 parts 6 functional aliphatic urethane acrylate (molecular weight 1000) 5 parts Initiator (Ciba, Irgacure 184) 5 parts Magenta ink 1 Magenta pigment dispersion 1 20 parts Stearyl acrylate 60 parts Bifunctional aromatic urethane acrylate (molecular weight 1500) 10 parts 6 functional aliphatic urethane acrylate (molecular weight 1000) 5 parts Initiator (Ciba, Irgacure 184) 5 parts Cyan ink 1 Cyan pigment dispersion 1 15 parts Stearyl acrylate 65 parts Bifunctional aromatic urethane acrylate (molecular weight 1500) 10 parts 6 functional aliphatic urethane acrylate (molecular weight 1000) 5 parts Initiator (made by Ciba Irgacure 184) 5 parts Black ink 1 Black pigment dispersion 1 15 parts Stearyl acrylate 65 parts Bifunctional aromatic urethane acrylate (molecular weight 1500) 10 parts 6 functional aliphatic urethane acrylate (molecular weight 1000) 5 parts Initiator (manufactured by Ciba, Irgacure 184) 5 parts White ink 1 White pigment dispersion 1 15 parts Stearyl acrylate 65 parts Bifunctional aromatic urethane acrylate (molecular weight 1500) 10 parts 6 functional aliphatic urethane acrylate (molecular weight 1000) 5 parts Initiator (manufactured by Ciba, Irgacure 184) 5 parts or more of ink was filtered with a filter having an absolute filtration accuracy of 2 μm to obtain an ink. The viscosity of the ink at 25 ° C is 8
0-150 mPa · s, viscosity at 70 ° C is 10-2
Surface tension at 0 mPa · s, 25 ° C is 240-28
It was 0 μN / cm. (Inkjet recording) Next, recording was performed on a recording material by an inkjet recording device using a piezo type inkjet nozzle. The ink supply system is an ink tank,
It consisted of a supply pipe, an anterior chamber ink tank just before the head, a pipe with a filter, and a piezo head. The anterior chamber ink tank and the head portion were insulated and heated. The temperature sensors were provided in the vicinity of the nozzles of the front chamber ink tank and the piezo head, respectively, and the temperature was controlled so that the nozzle portion was always at 60 ° C ± 2 ° C. The piezo head has a nozzle diameter of 24
720 x multi-size dots of 8 to 30 pl in μm
720 dpi (dpi is 1 inch, or 2.54 cm
It is driven so as to be able to eject at a resolution of (per dot). Using the above ink, at the ambient temperature of 25 ° C., white, black, cyan, magenta, and yellow were ejected in this order, and UV light was irradiated for each color.

After the ink has landed, as shown in Table 1, the UV illuminance of the exposure surface of the primary exposure (shown by the primary exposure intensity (mW / cm ² ) in Table 1) and the irradiation timing of the secondary exposure (Table In No. 1, (second) indicated by the secondary exposure timing was controlled.
The irradiation of the primary exposure was controlled to be within 0.2 seconds after landing. The exposure surface illuminance of the secondary exposure was 300 mW / cm ² . As recording material, PET (polyethylene terephthalate) film, surface-treated OP with printability
Color images were recorded on P (biaxially oriented polypropylene) film, OPS (biaxially oriented polystyrene) film and cast coated paper. Then, the following evaluations were performed, and the results are shown in Table 1. (Evaluation) -Gloss glossiness was measured by measuring 60-degree specular glossiness according to JIS-Z-8741. The measurement was performed using a variable angle gloss meter (VGS-1001DP) manufactured by Nippon Denshoku Industries Co., Ltd.・ Concentration Concentration is measured by Gretag Spectroli
The DG density of the black ink was measured with no. Bleeding The bleeding was visually evaluated according to the following evaluation criteria.

[0116] ○: No bleeding △: There is a slight blur between the two colors ×: Bleeding between the two colors is severe

[0117]

[Table 1]

When the gloss is 10 or less, the texture is obviously different and a feeling of strangeness is felt. As shown in Table 1, there are no conditions under which all the gloss, density, and bleeding are satisfied under the same conditions. But,
By controlling the irradiation conditions according to the recording material, gloss, density and bleeding could be satisfied.

Example 2 A printing plate material provided with a porous hydrophilic layer shown below was used as a recording material. -Preparation of printing plate material An undercoat layer consisting of two layers was formed on a PET film having a thickness of 0.18 mm by the following method to obtain a support. 1) After subjecting the coated surface of the first undercoat layer PET film to corona discharge treatment,
A coating solution having the following composition was applied by a wire bar in an atmosphere of 20 ° C. and a relative humidity of 55% so that the film thickness after drying would be 0.4 μm. Then, it was dried at 140 ° C. for 2 minutes. (First undercoat layer composition) Acrylic latex particles: n-butyl acrylate / t-butyl acrylate / styrene / hydroxyethyl methacrylate = 28/22/25/25 36.9 g Surfactant (A) 0.36 g Hardener (A) 0.98 g Distilled water was added to the above to make 1000 ml, which was used as a coating liquid. 2) Second undercoat layer After subjecting the surface of the above film on which the first undercoat layer is formed to corona discharge treatment, a coating solution having the following composition is dried by an air knife method in an atmosphere of 35 ° C. and a relative humidity of 22%. It was applied so that the subsequent film thickness would be 0.1 μm. Then 14
It was dried at 0 ° C. for 2 minutes. (Second undercoat layer composition) Gelatin 9.6 g Surfactant (A) 0.4 g Hardener (b) 0.1 g Distilled water was added to the above to make 1000 ml, to give a coating solution.

[0120]

[Chemical 1]

Subsequently, a coating solution for the porous hydrophilic layer having the following composition was prepared, filtered, and then coated on the second undercoat layer using a # 10 wire bar and dried at 80 ° C. for 5 minutes.
The coating film surface after drying had a matte texture, and it was confirmed by microscopic observation of the coating film surface that an uneven structure having a pitch of 1 to 5 μm was formed on the surface. The ratio of materials that do not contain carbon atoms in this composition is 98.9% by mass.
Is. (Composition of coating liquid for porous hydrophilic layer) Colloidal silica (alkali type) Snowtex-S 19.73 parts (Nissan Chemical Co., Ltd., solid content 30% by mass) Necklace-shaped colloidal silica (alkali type) 44.30 parts Snowtex -PSM (Nissan Chemical Co., Ltd., solid content 20 mass%) Porous metal oxide particles Silton AMT08 3.50 parts (Mizawazawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 0.6 μm) Porous metal oxide Particles AMT-silica 300B 1.00 parts (Mizusawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 3 μm) Layered clay mineral particles Montmorillonite BENGEL-31 8.00 parts (Toyosyun Yoko, pH (2%) 10.1, swelling power (ml / 2g): 48 viscosity (cps-6 rpm); 2500 (concentration 2%)) with a homogenizer Stirred to make a 5% by weight water-swelling gel 4% by weight aqueous solution of sodium carboxymethylcellulose 5.00 parts (Kanto Chemical Co., Inc. reagent) trisodium phosphate 12 water 1.00 parts (Kanto Chemical Co., Inc. reagent 10% by weight aqueous solution Si-based surfactant FZ2161 2.00 parts (manufactured by Nippon Unicar Co., Ltd.) 1% by weight aqueous solution to which pure water is added to obtain 20% by weight of solid content, and the mixture is sufficiently stirred using a homogenizer. Mixed. Then, it was aged at 55 ° C. for 24 hours to obtain a printing plate material. -Preparation of ink An ink having the following formulation was prepared. Ink composition Oil-soluble black dye (Nigrosine black) 0.5 part Stearyl acrylate 62.5 parts Bifunctional aromatic urethane acrylate (molecular weight 1500) 10 parts p-toluene sulfonic acid 2 parts Silicone varnish 20 parts Initiator (Ciba, Irga Cure 184) 5 parts (inkjet recording) Next, in the same manner as in Example 1, the above ink was ejected to perform recording on the printing plate material, and then UV curing was performed.

After the ink has landed, UV light is irradiated on the exposed surface of the primary exposure as shown in Table 2 (indicated by the primary exposure intensity (mW / cm ² ) in Table 2) and irradiation timing of the secondary exposure (see Table ² ). In No. 2, (second) indicated by the secondary exposure timing was controlled.
The irradiation of the primary exposure was controlled to be within 0.2 seconds after landing. The exposure surface illuminance of the secondary exposure was 300 mW / cm ² . Then, the following evaluations were performed, and the results are shown in Table 2. (Evaluation) -Printing durability Using the obtained printing plate, printing equipment: DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd., coated paper, fountain solution (concentration of H liquid SG-51 manufactured by Tokyo Ink Co., Ltd.) 1.5%), ink (Toyo Ink Co., Ltd. Toyo King High Echo M Beni)
Was printed using. Printing durability is evaluated by the number of printed sheets,
The evaluation was made by the number of sheets until the image area was scratched or the non-image area was stained (ground stain). Fine line reproducibility The fine line reproducibility was visually evaluated according to the following evaluation criteria.

[0123] ○: No fine line disturbance △: Fine lines are slightly disturbed ×: Reproduction of fine lines is obviously degraded

[0124]

[Table 2]

As is clear from Table 2, by controlling the exposure timing, it was possible to obtain a printing plate having higher image quality and higher printing durability.

[0126]

According to the present invention, a radiation-curable ink can be ejected to obtain a high-resolution image without bleeding, and high-quality recording can be performed on various recording materials. Produce the effect.

Claims (10)

[Claims] 1. An ink jet recording method characterized in that after a radiation curable ink is ejected onto the surface of a recording material, the glossiness of an image forming portion is adjusted by controlling the amount of energy of radiation that cures the ink that has landed. . 2. A glossiness of an image forming portion is adjusted by controlling a time period from the time when the radiation curable ink is ejected to the surface of the recording material until the time when the radiation ink for curing the landed ink is irradiated is controlled. Inkjet recording method. 3. The ink jet recording method according to claim 1, wherein the glossiness is adjusted only in a predetermined image area. 4. The ink jet recording method according to claim 1, wherein the radiation curable ink has a viscosity at 25 ° C. of 35 to 500 mPa · s. 5. The ink jet recording method according to claim 1, wherein the base material of the recording material is non-ink-absorbing. 6. The maximum portion of the printing film thickness of the image forming portion is 5 to 5.
It is 60 micrometers, The inkjet recording method of any one of Claims 1-5 characterized by the above-mentioned. 7. The ink jet recording method according to claim 1, wherein the recording material is a printing plate material having a porous hydrophilic property on a substrate. 8. The ink jet recording according to claim 7, wherein the recording material has a porous hydrophilic layer, and 91% by mass or more of the material constituting the porous hydrophilic layer does not contain carbon atoms. Method. 9. The ink jet recording method according to claim 8, wherein the material containing carbon atoms in the porous hydrophilic layer contains a saccharide. 10. An inkjet recording apparatus, wherein the inkjet recording method according to claim 1 can be used to adjust the glossiness of an image forming portion.