JP2005231106A - Intermediate transferring medium for inkjet recording, method for manufacturing it and method for forming image using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transferring medium for inkjet recording which has a high resolution, has no problem such as color bleeding and cockling, has good transferring properties to a wide range of printing papers, has a similar feeling on textures of an imaging part/a non-imaging part on a medium to be recorded after transferring to the medium to be recorded, and can be used as a proof for the uses for proof reading of printing or the like, and a method for manufacturing it, and also to provide a method for forming an image capable of performing a good inkjet recording. <P>SOLUTION: The intermediate transferring medium for inkjet recording having the second ink absorbing layer and the first ink absorbing layer in this order on a substrate is characterized by forming releasably the first ink absorbing layer from the intermediate transferring medium, and providing furthermore a hydrophobic layer on the upper layer of the first ink absorbing layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an intermediate recording medium for inkjet recording used for forming an image on a recording medium by transfer, a method for producing the same, and an image forming method using the intermediate transfer medium for inkjet recording.

  The ink jet recording method is non-contact recording, and can be used from a small recording device to a large device, and can be easily colored, so that it is widely used from personal use to industrial use.

  As the recording liquid, solvent type and water type inks have been proposed, but water type inks are widely used except for some industrial applications.

  Such a system using water-based ink has been studied for application to a photographic use, a color proof use, and the like with the recent improvement in image quality. In addition, the accuracy of related technologies such as color matching has been improved, and it has been used as a school for proof applications that require a strict color gamut, and there is an increasing demand for output quality with high density and high saturation that more closely approximates printing. Yes.

  Various image forming methods used for proofreading of printing other than the above are studied and commercialized, including laser melting thermal transfer method, laser sublimation thermal transfer method, laser ablation transfer method, silver salt method, etc. Is very expensive and has not swept the market.

  Comparing the currently used “high-end image forming system” with the current image forming system using ink jet, the ink jet system has the advantage that the equipment is simple, the system price can be greatly reduced, and the running cost can be greatly reduced. There is. However, resolution such as fine line reproducibility and character reproducibility, gradation expression of shadow portions, etc. are inferior and are not recognized as a color proof for final confirmation.

  Technologies to fill the above differences are being examined by various companies, and in particular, ink jet paper that is similar to printing paper has been developed one after another by paper manufacturers, etc., matte paper, coated paper, etc. It is becoming a situation where quality close to is obtained. However, no inkjet recording paper has been proposed that targets lightweight coats, lightweight matte paper, and newspaper.

  Such an inexpensive system is a field that is expected to be compatible with printing papers used in flyers and magazines such as lightweight coats, lightweight matte papers, and newspapers. Inkjet recording ejects liquid onto recording paper. However, when output to thin paper, there is a problem that essentially sufficient quality cannot be obtained due to problems such as cockling and overflow.

  As an effective technique for such a problem, a method using an intermediate transfer medium has been proposed in the past. JP-A-62-22849 and JP-A-1-226336 disclose an ink as an intermediate transfer medium. A method for suppressing permeation into a recording medium is disclosed by adhering the ink to the recording medium, evaporating the moisture of the ink by heating, concentrating, and then pressing and transferring the intermediate transfer medium to the recording medium. According to this, it is possible to improve the blurring of the image and the breakthrough of the recording medium. However, since the ink droplets gather and form a spherical shape in the process from discharging the ink onto the intermediate transfer medium to transferring it to the recording medium, the dot diameter increases and the resolution decreases, or the image is accurately positioned. There was a problem of not being retained. In addition, when different colors of ink are ejected adjacently, not only color mixing occurs, but the presence of the previously ejected ink causes the next ink to be repelled and spattered, resulting in reduced image clarity. There was a problem.

  In order to solve the above problems, Japanese Patent Application Laid-Open No. 11-291478 discloses a method of transferring to a recording medium after discharging to an intermediate transfer medium having an intermediate transfer layer that is porous and absorbs ink and can be discharged. ing. According to this, it is possible to improve resolution reduction, color mixture, spatter, and the like. However, the color material is not sufficiently transferred to the recording medium to hold the ink in the pores, so that a high-saturation image cannot be obtained. In repeated recording, the previous image is not sufficiently cleaned and the ghost is not obtained. There was a problem such as

  In addition, there is an essential problem in a method for improving bleeding and back-through by using an intermediate transfer medium for these water-based inks. Most of the composition of the water-based ink is a solvent and a coloring material, and volume shrinkage occurs due to evaporation / concentration of the solvent, and transferability to a recording medium is deteriorated. For this reason, transferability and improvement of bleeding and show-through cannot be achieved at the same time.

  On the other hand, JP-A-10-16382, JP-A-11-42896, and JP-A-20002000 perform inkjet recording on a transfer layer that is detachably provided on an intermediate transfer medium, and then transfer the transfer layer to a recording medium. -1044, and the like. This is a preferred method because, in principle, the transferability of the color material to the recording medium is improved.

  However, in these methods, there is insufficient absorption of the solvent in the transfer layer, and there are problems such as a decrease in resolution and color mixing on the intermediate transfer medium. In addition, transferability to printing paper with a large surface roughness such as matte paper or high-quality paper is insufficient, the image after transfer is accompanied by color turbidity due to low transparency of the image receiving layer, or on the final image carrier. However, the image quality of the image area / non-image area of the image quality of the image area / non-image area is significantly different from that of the recording medium.

Patent Document 1 discloses a method in which the ink absorption layer is divided into two layers and only the upper layer is transferred to bring the difference in texture and glossiness on the final image carrier, but in this method, ink landing is performed. At that time, the dot diameter control is insufficient, and it is insufficient for the formation of an image for printing proof that requires both a very high resolution and gradation.
JP 2002-307815 A

  The present invention has been made in view of the above circumstances, and its purpose is high resolution, no problem of color bleeding, cockling, etc., good transferability for a wide range of printing paper, and after transfer. To provide an intermediate transfer medium for ink-jet recording that can be suitably used as a proof for printing school use and the like, since the texture of the image area / non-image area on the recording medium is similar to that of the recording medium. It is. It is another object of the present invention to provide an image forming method capable of performing good ink jet recording using it.

(Claim 1)
An intermediate transfer medium for ink jet recording having a second ink absorbing layer and a first ink absorbing layer in this order on a support, wherein the first ink absorbing layer is formed to be peelable from the intermediate transfer medium, and An intermediate transfer medium for ink-jet recording, wherein a hydrophobic layer is provided on an upper layer of the first ink absorbing layer.

(Claim 2)
An intermediate transfer medium for ink jet recording having a second ink absorbing layer and a first ink absorbing layer in this order on a support, wherein the first ink absorbing layer contains a hydrophobic resin, and the first ink absorbing layer An intermediate transfer medium for ink-jet recording, wherein the layer is formed so as to be peelable from the intermediate transfer medium.

(Claim 3)
The intermediate transfer medium for ink-jet recording according to claim 1 or 2, wherein the first ink absorbing layer has a thickness of 0.2 to 5 µm.

(Claim 4)
4. The intermediate transfer medium for ink-jet recording according to claim 1, wherein the second ink absorbing layer is a void-type absorbing layer containing porous silica.

(Claim 5)
5. The method for producing an intermediate transfer medium for ink jet recording according to claim 2, 3 or 4, wherein the first ink absorbing layer is produced by applying and drying a mixture of colloidal silica and a hydrophobic resin emulsion. A method for producing an intermediate transfer medium for inkjet recording.

(Claim 6)
An image forming method using the intermediate transfer medium for ink jet recording according to any one of claims 1 to 4, wherein the ink jet ink used for image formation is a water-based pigment ink, and the average particle diameter of the contained pigments Is 0.1 to 3 μm.

(Claim 7)
An image forming method using the intermediate transfer medium for ink jet recording according to any one of claims 1 to 4, wherein the final image carrier and the intermediate transfer medium are printed on the intermediate transfer medium with an aqueous pigment ink. And the first ink absorbing layer is transferred to the final image carrier with at least one of heat and pressure.

(Claim 8)
8. The image forming method according to claim 6, wherein an image is formed using an inkjet image forming apparatus having ink droplets of 2 pl or less.

  According to the present invention, high resolution, no problem of color bleeding, cockling, etc., good transferability to a wide range of printing paper, and the texture of the image / non-image area on the recording medium after recording are recorded. Since it is similar to a medium, it is possible to provide an intermediate recording medium for inkjet recording that can be suitably used as a proof for printing out-of-school applications, etc., and a method for producing the same. An image forming method can be provided.

  Next, the material compound, layer structure, image forming method and the like that can be suitably used in the present invention will be further described.

[Support]
As the support used for the intermediate transfer medium, a conventionally known support can be used without particular limitation. The thickness is preferably 6 to 200 μm, more preferably 25 to 125 μm.

  Examples of the support include various papers such as paper, coated paper, and synthetic paper (polypropylene, polystyrene, or a composite material obtained by bonding them to paper), vinyl chloride resin sheets, ABS resin sheets, polyethylene terephthalate films, Polybutylene terephthalate film, polyethylene naphthalate film, polyarylate film, polycarbonate film, polyether ketone film, polysulfone film, polyether sulfone film, polyetherimide film, polyimide film, polyethylene film, polypropylene film, polystyrene film, stretched A single layer of nylon film, polyacetate film, etc., or various plastic films or sheets in which two or more layers are laminated, and a film formed of various metals. Beam or sheet, various ceramics such in the formed film or sheet of, further, aluminum, stainless steel, chromium, metal plate such as nickel, followed by a metal thin film to the paper was resin coated and laminated or deposited. Among these, paper is preferable from the viewpoint of preventing bleeding due to absorption of the ink solvent overflowing from the ink absorption layer.

  These supports can be subjected to various processes such as dimensional stabilization and antistatic. Examples of the antistatic agent include a cationic surfactant, an anionic surfactant, a nonionic surfactant, a polymer antistatic agent, and conductive fine particles, as well as “11290 Chemical Products”, Chemical Industry Daily, 875- The compounds described in page 876 and the like can be widely used.

  Conventionally known surface modification techniques can also be suitably used. Examples of the adhesion treatment for improving the adhesion include flame radiation treatment, sulfuric acid treatment, corona discharge treatment, and plasma treatment. It is also preferable to use a support in which an adhesive layer is previously applied to the support.

Among these, the corona discharge treatment and the introduction of the adhesive layer are particularly preferable. The support film surface output during the corona discharge treatment is preferably ²⁰ to 80 W / m ² , particularly preferably 30 to 70 W / m ² .

  A conventionally well-known thing can be especially used as a contact bonding layer without a restriction | limiting. Examples of the method for providing the adhesive layer include water-based resin coating, solvent-based resin coating, water-based latex coating, and hot melt coating.

  As the design of the adhesive layer, 1) select a material having intermediate properties between the solubility parameters of the support and the upper layer, 2) select a material containing a reactive group in the support and the upper layer, and 3) tackiness. / It is possible to set appropriately, for example, by selecting substances having different slip properties.

  In general, it is advantageous to provide an adhesive layer at the time of preparing the support from the viewpoints of cost, stability and the like. From this point, for example, acrylic resin, polystyrene resin, polyester resin, urethane resin, polyethylene / vinyl acetate resin A method of applying latex such as is preferable, but not particularly limited thereto.

  Such a film base with an adhesive layer is sold by various companies, and these can be suitably used. For example, W-900E, W-900J, W-400J, T-100E, T-600E, S410E, S110G, T600G, H100C, H500, H160L (manufactured by Mitsubishi Polyester), P60, Q80, Q81, Q82, Q83, Q27, P51, P52, P525, P025, S90, S91, S92, S94, S95, T90, T91, T94, T95, T98, T99, U94, U98, U99, X94 (manufactured by Toray Industries, Inc.), UL9, U51L74, U51LY (manufactured by Teijin Ltd.), 535, 705, 505, 339, 330, 534 (manufactured by DuPont) and the like.

  The intermediate transfer medium has a support having a surface roughness Ra of 10 nm to 5 μm, more preferably 15 nm to 3 μm, and particularly preferably 20 nm to 1 μm. Adhesiveness between the thermally deformable layer and the lower layer or the support due to the anchor effect It is preferable from the viewpoint of improvement. Furthermore, Ra is preferable from the viewpoint of image defects when the fluidity of the heat-deformed layer is improved and the unevenness followability of the final image carrier is improved.

  In the present invention, the surface roughness Ra of the support is defined by a surface roughness meter (manufactured by RST / PLUS WYCO).

  From such a point of view, as the support, those obtained by positively adding a matting agent, sandblasted or embossed for the purpose of improving the slipperiness can be preferably used.

  A white support kneaded with a white pigment or the like is very preferable from the viewpoint that a desired surface roughness can be stably obtained due to the presence of uniform fine particles.

On the other hand, since the intermediate transfer medium thermally transfers the image to the final image carrier, it is important in handling that the front and back can be easily distinguished when the image is formed on the ink absorbing layer. From this point, among the white supports, when defined by the lightness index L ^* and the perceptual chromaticity indices a ^* and b ^* in the CIE color space, 60 or more is preferable and more preferable when expressed by L ^* of the support. Is 80 or more. Further, a ^* and b ^* are preferably a ^* : −10 to +10, b ^* : −10 to +10, and a white support having a ^* : −5 to +5 and b ^* : −5 to +5. This is a more preferable embodiment.

The L ^* a ^* b ^* values defined in the present invention can be measured using Gretag SPM-100 and a standard black backing for color measurement.

[Ink absorbing layer]
In the present invention, the ink absorption layer is composed of a plurality of layers, and is divided into at least a first ink absorption layer and a second ink absorption layer. These layers are separated when an image is retransferred to a desired recording medium after ink jet recording, and only the first ink absorption layer is transferred to the recording medium.

Further, for the purpose of obtaining good recording quality, the ink absorbing layer preferably has a transfer amount of 5 to 200 ml / m ² in a contact time of 1 second of an ethylene glycol 25% aqueous solution in a liquid absorbency test by the Bristow method. More preferably, it is 10 to 150 ml / m ² . That is, when the solvent absorption is 5 to 200 ml / m ² , the phenomenon that ink droplets adhering to the surface of the intermediate transfer medium during ink jet recording overflow or bleed is suppressed.

  The liquid absorbency test by the Bristow method in the present invention (refer to J.TAPPI paper pulp test method No. 51 for details) is a contact time of 1 second determined by adding 15 μl of 25% aqueous solution of ethylene glycol to the head box. The liquid dynamic absorption tester manufactured by Kumagai Riki Kogyo Co., Ltd. is used as the Bristow test device.

[First ink absorbing layer]
First, the first ink absorbing layer will be described. The first ink absorbing layer contains at least a hydrophobic resin.

  The hydrophobic resin in the present invention refers to a resin having a surface tension of 450 μN / cm or less, preferably a resin having a surface tension of 350 μN / cm or less.

  Examples of the hydrophobic resin include resins such as polyurethane, polyalkylene, PET, polyester, polystyrene, polysulfone, polyamide, polyacetal, acrylic, and ABS. In order to further increase the hydrophobicity, a resin into which a fluorine atom is introduced is also preferably used.

  Hydrophobic resins can be used alone or in combination of two or more. The first ink absorbing layer preferably has thermoplasticity. Therefore, it is very preferable that at least one of the hydrophobic resins used in the ink absorbing layer is a thermoplastic resin. A preferred configuration is a system in which a fluororesin having a large effect of reducing the surface energy of the layer and a resin having good thermoplasticity are mixed.

  The ink absorbing layer can be manufactured by applying the ink absorbing layer coating liquid onto a support and drying it. Considering the stability, classification, and solubility of the coating liquid, the ink absorbing layer can be treated with other materials. It is preferable to mix to prepare a coating solution.

  The first ink absorbing layer needs to have a composition that absorbs and transmits ink in addition to the hydrophobic resin. As the ink absorbing layer, a well-known swelling type or void type ink absorbing layer is used, but a void type is preferable from the viewpoint of ink water absorption speed.

  The void-type ink absorbing layer has a void in the ink absorbing layer, and is preferably a porous film having a void containing inorganic fine particles and a small amount of a hydrophilic polymer. Examples of such inorganic fine particles include, for example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, carbonate White inorganic such as zinc, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, magnesium hydroxide A pigment etc. can be mentioned. Such inorganic fine particles can be used as primary particles or in a state where secondary agglomerated particles are formed.

  In the present invention, synthetic amorphous silica, colloidal silica, or pseudoboehmite is preferred from the viewpoint of forming fine voids, and the average particle size (referring to the average particle size of primary particles) is 100 nm or less. Silica, colloidal silica and pseudoboehmite synthesized by the phase method are preferred. Furthermore, silica synthesized by a vapor phase method having an average particle diameter of 100 nm or less is particularly preferable in that the effects of the present invention are further exhibited.

  The average particle size of the inorganic fine particles can be obtained as a simple average value (number average) by observing the cross section or surface of the particle itself or the void layer with an electron microscope and determining the particle size of 100 arbitrary particles. Here, each particle size is represented by a diameter assuming a circle equal to the projected area.

  As the hydrophilic polymer used in the void layer, the same hydrophilic polymer used in the swelling ink absorbing layer is used, but a preferred hydrophilic polymer is polyvinyl alcohol. The polyvinyl alcohol preferably used includes, in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, modified polyvinyl alcohol such as polyvinyl alcohol having a terminal cation modified or anionic modified polyvinyl alcohol having an anionic group. It is.

  The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 300 or more, and particularly preferably has an average degree of polymerization of 1000 to 5000. The saponification degree is preferably 70 to 100%, particularly preferably 80 to 99.5%.

  Further, the ratio of the inorganic fine particles and the hydrophilic binder used in the ink absorbing layer is usually preferably 2: 1 to 10: 1 by mass ratio, and particularly preferably 3: 1 to 8: 1. By setting the ratio of the inorganic fine particles to the hydrophilic binder to a large value as described above, the ink absorption layer can achieve a high porosity. A preferable porosity is 40 to 80%, and 50 to 70% is particularly preferable. The porosity is a value obtained according to the following formula.

Porosity = 100 × [(total dry film thickness−applied solid film thickness) / total dry film thickness]
Further, when the void layer contains polyvinyl alcohol as a hydrophilic polymer, it is preferable to add a hardener to improve the film forming property of the film and increase the strength of the film. Boric acid or a salt thereof, among which boric acid or a salt thereof is preferable. As boric acid or a salt thereof, an oxygen acid having a boron atom as a central atom and a salt thereof are shown. Specifically, orthoboric acid, metaboric acid, hypoboric acid, tetraboric acid, pentaboric acid and salts thereof are included.

  The amount of boric acid or a salt thereof used can vary widely depending on the amount of inorganic fine particles and hydrophilic polymer in the coating solution, but is usually 1 to 60% by mass, preferably 5 to 40% by mass with respect to the hydrophilic polymer.

  In the present invention, the ink absorption speed is high, the image unevenness is small, and the amount of curling is small because the amount of the hydrophilic polymer used is relatively small. Therefore, the ink absorption layer is a porous film having voids. Is preferred.

  In the present invention, if necessary, an activator, an antiseptic, an antioxidant, a UV absorber, a white background adjusting dye, a plasticizer, and the like can be added to the first ink absorption layer.

  The maximum absorbance at 400 to 700 nm of the first ink absorbing layer after transfer to the recording medium is preferably 0.2 or less, particularly preferably 0.15 or less, and further preferably 0.1 or less.

  Further, the gloss of 60-60 ° through the first ink absorbing layer after being transferred to the recording medium is preferably within ± 15, and particularly preferably within ± 10, relative to the gloss inherent to the recording medium.

  Further, the difference between the absorption rate of the 25% aqueous ethylene glycol solution in the first ink absorption layer and the absorption rate of the second ink absorption layer is preferably ± 30%, particularly preferably ± 20%. When the difference is larger than the above range, an ink liquid pool is generated on the first ink absorption layer surface or the second ink absorption layer surface, and image quality is deteriorated during printing and transfer.

  In addition, it is preferable that the film thickness of a 1st ink absorption layer is 0.2-5.0 micrometers. The film thickness may be measured with a known film thickness measuring device, or the cross-section of the coating layer may be observed with a microscope, and the average film thickness may be determined by observation. If the film thickness is less than 0.2 μm, the peelability deteriorates, and if it is greater than 5.0 μm, the transparency and the texture of the image deteriorate, and a desired high-quality image cannot be obtained.

[Second ink absorbing layer]
Next, the second ink absorbing layer will be described. The second ink absorbing layer is not required to have transparency as described above. As the water absorbing layer, a known void type or swelling type composition used for the first ink water absorbing layer can be used.

  In addition, the compound used by said 1st ink absorption layer can be used conveniently for a 2nd ink absorption layer. However, it is more preferable to use a highly hydrophilic binder as the second ink absorbing layer. Moreover, it is also preferable to add and use a filler.

  Among these, the second ink absorption layer of the present invention is preferably a void-type ink absorption layer containing porous inorganic particles such as porous silica, porous aluminum / silicate, zeolite, and more preferably a void-type ink containing porous silica. It is an ink layer.

  The porous silica particles are generally produced by a wet method or a dry method. In the wet method, the gel obtained by neutralizing an aqueous silicate solution can be obtained by drying and pulverizing, or by pulverizing the precipitate deposited after neutralization. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica. These particles can be controlled in porosity and particle size by adjusting production conditions. As the porous silica particles, those obtained from a wet gel are particularly preferable. When the colloidal silica is used as the porous silica, it is preferable because it is excellent in separability from other materials, coating properties, and the like.

  In the present invention, the second ink absorbing layer is characterized in that the applied amount is larger than that of the first ink absorbing layer, and the second ink absorbing layer is based on the total mass of the first / second ink absorbing layer. The mass occupied by the absorption layer is preferably 70 to 99.9%, particularly preferably 75 to 99.5%.

Further, the amount of the second ink absorbing layer is preferably 40 to 100 g / m ² in the case of serving also as a support, and preferably 5 to 30 g / m ² in other cases, and particularly preferably 8. ˜25 g / m ² .

  The intermediate transfer medium of the present invention retransfers an image onto a recording medium after inkjet recording. Although this process will be described in detail later, a final image is obtained through a peeling process after retransfer.

  In the present invention, the term “peelable” means that the peeling force when peeling the first ink absorbing layer is 10 to 5,000 mN / cm.

[Hydrophobic layer (coating film)]
The hydrophobic coating film used in the present invention is obtained by applying a known hydrophobic substance on the first ink absorbing layer. Examples of the hydrophobic substance include paraffin, polyolefin, polyethylene wax, microcrystalline wax, and fatty acid wax.

  These have a molecular weight of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups. Furthermore, in order to lower the softening point and improve the workability, these waxes are stearamide, linolenamide, laurylamide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, coconut fatty acid amide. Alternatively, methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide, and the like can be added. Coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, xylene resin, ketone resin, acrylic resin, ionomer, polyurethane, polyester, polystyrene, polysulfone, or a copolymer of these resins can also be used. .

  In the present invention, it is important to suppress the spread of droplets on the surface layer as much as possible, and to maintain a good water absorption rate so that it can withstand high-speed printing. For this purpose, the hydrophobic coating must be thin enough It is. A preferred thickness of the hydrophobic layer is 0.05 to 1.0 μm.

[Other layers]
In this invention, it is a preferable aspect to provide a backcoat layer as needed. In order to impart functions such as transportability, heat resistance, and antistatic properties to the back surface (the surface opposite to the surface on which the ink absorption layer is provided) of the support, it is preferable to provide a backcoat layer. Further, the provision of the back coat layer is effective for image defects and image quality stability.

  The backcoat layer can be formed by applying a backcoat layer coating solution in which a binder resin is dissolved in a solvent or a binder resin and a matting agent having a particle size of 2 to 30 μm are dissolved or dispersed in a solvent on the back surface of the support. .

  Binders used in the back coat layer include gelatin, polyvinyl alcohol, methyl cellulose, nitrocellulose, acetyl cellulose, aromatic polyamide resin, silicone resin, epoxy resin, alkyd resin, phenol resin, melamine resin, fluorine resin, polyimide resin, urethane Resin, acrylic resin, urethane-modified silicone resin, polyethylene resin, polypropylene resin, polyester resin, Teflon (R) resin, polyvinyl butyral resin, vinyl chloride resin, polyvinyl acetate, polycarbonate, organic boron compound, aromatic ester, fluoride General-purpose polymers such as polyurethane and polyethersulfone can be used.

  The backcoat layer preferably has a scratch resistance of 10 g or more (10 to 500 g), more preferably 20 g or more (20 to 500 g) in a 0.1 mmR needle scratch tester.

  The scratch test is measured by the following method. That is, a back coat layer is provided on a support, and the measurement is performed after being left in an environment of 23 ° C. and 50% RH for one day. The measuring instrument was a scratch strength tester HEIDON-18 (manufactured by HEIDON), and the measuring needle was a 0.1 mmR sapphire needle. For the measurement, a 10 cm scratch test at a constant load is performed three times, and the limit load at which there is no scratched part up to the support is defined as the scratch strength of the present invention.

The back coat layer preferably contains a matting agent. As the matting agent preferably added to the backcoat layer, organic or inorganic fine particles can be used. Examples of the organic matting agent include polymethyl methacrylate (PMMA), polystyrene, polyethylene, polypropylene, fine particles of other radical polymerization polymers, fine particles of condensation polymers such as polyester and polycarbonate, fine particles of fluorine resin, silicon resin, and the like. . In order to increase the strength and solvent resistance of the particles, crosslinked organic fine particles are more preferable. The back coat layer is preferably provided at a weight of about 0.5 to 5 g / m ² . If it is less than 0.5 g / m ² , the coating property is unstable, and problems such as powdering off of the matting agent are likely to occur. On the other hand, if the coating amount exceeds 5 g / m ² , the particle size of a suitable matting agent becomes very large, which is not preferable because of high cost.

The matting agent preferably has a number average particle diameter that is 1 to 20 μm larger than the film thickness of only the binder of the backcoat layer. Among the matting agent, 2 [mu] m or more particles having a particle size of 5 mg / m ² or more is required, preferably 6~600mg / m ^2. This particularly improves the storage stability of the intermediate transfer medium. Further, by using a narrow particle size distribution such that a value σ / rn (= coefficient of variation of the particle size distribution) obtained by dividing the standard deviation of the particle size distribution by the number average particle size is 0.3 or less, In addition to improving the loss of particles generated by particles having an abnormally large particle size, desired performance can be obtained with a smaller addition amount. The variation coefficient is more preferably 0.15 or less.

  The average particle size of the matting agent particles is the sphere equivalent diameter of each particle, and the arithmetic mean value of the sphere equivalent diameter is obtained by taking a transmission electron micrograph by the replica method and processing the projection area and shadow information. It is easily obtained by calculating. In determining the diameter in terms of sphere, it is necessary to randomly extract at least 1000 particles.

  The surface roughness Ra of the backcoat layer is preferably 30 nm to 5 μm, more preferably 50 nm to 4 μm, and particularly preferably 80 nm to 3 μm. The back coat layer surface roughness Ra is defined by a surface roughness meter (manufactured by RST / PLUS WYCO) as in the case of the support.

  Furthermore, it is preferable to add an antistatic agent to the backcoat layer in order to prevent adhesion of foreign matters due to frictional charging with the transport roll during sheet supply. Examples of the antistatic agent include a cationic surfactant, an anionic surfactant, a nonionic surfactant, a polymer antistatic agent, and conductive fine particles, as well as “11290 Chemical Products”, Chemical Industry Daily, 875- The compounds described on page 876 and the like are widely used. As the antistatic agent added to the backcoat layer, among the above substances, metal oxides such as carbon black, zinc oxide, titanium oxide and tin oxide, and conductive fine particles such as organic semiconductors are preferably used. In particular, it is preferable to use conductive fine particles because the antistatic agent is not dissociated from the backcoat layer and a stable antistatic effect can be obtained regardless of the environment.

  Further, various activators, mold release agents such as silicon oil, fluorine-based resins, and the like can be added to the back coat layer in order to impart coatability and mold release properties. The addition of a release agent to the backcoat layer is particularly preferable when the softening point measured by TMA of the heat-deformable layer and the ink absorbing layer is 70 ° C. or less.

[Inkjet ink]
The ink used in the present invention is preferably a water-based pigment ink. In the case of a dye system, a sufficient concentration cannot be obtained because no dye remains in the layer to be peeled and transferred. Since pigment particles remain on the outermost layer of the pigment ink, an image having a high density can be obtained.

  From the viewpoint of image storage stability, it is preferable to use an aqueous pigment ink using a pigment as a colorant (coloring material). As the pigment used in the pigment ink, insoluble pigments, organic pigments such as lake pigments, carbon black and the like can be preferably used.

  The particle size of the pigment is preferably 0.1 to 3.0 μm. If it is smaller than 0.1 μm, it will pass through the first ink absorption layer and an appropriate density cannot be obtained, and if it is 3.0 μm or more, the ability to emit light from the inkjet head will deteriorate.

  The insoluble pigment is not particularly limited. Dioxazine, thiazole, phthalocyanine, diketopyrrolopyrrole and the like are preferable.

  Specific pigments that can be preferably used include the following pigments.

  Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. And CI Pigment Yellow 138.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  For these pigments, a pigment dispersant may be used as necessary. Examples of pigment dispersants that can be used include higher fatty acid salts, alkyl sulfates, alkyl ester sulfates, alkyl sulfonates, sulfosuccinates. Acid salt, naphthalene sulfonate, alkyl phosphate, polyoxyalkylene alkyl ether phosphate, polyoxyalkylene alkyl phenyl ether, polyoxyethylene polyoxypropylene glycol, glycerin ester, sorbitan ester, polyoxyethylene fatty acid amide, amine Activators such as oxides, or styrene, styrene derivatives, vinyl naphthalene derivatives, acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, fumaric acid derivatives Block copolymer comprising a monomer of the above, a random copolymer and can be exemplified salts thereof.

  As a method for dispersing the pigment, various dispersing machines such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used. It is also preferable to use a centrifugal separator or a filter for the purpose of removing the coarse particles of the pigment dispersion.

  It is preferable to add thermoplastic resin particles to the ink for the purpose of increasing adhesion to the recording medium and image strength on the recording medium. It is particularly preferable to coat the dispersed particles of the colorant with a thermoplastic resin. As a combination with the colorant, the thermoplastic resin particles can be suitably used for a dissolved dye system, a dispersed dye system, and a dispersed pigment system, and the thermoplastic resin coat is particularly suitable for a dispersed dye system and a dispersed pigment system. Can be used. The thermoplastic resin particles preferably have a melting point of 30 ° C. or higher, more preferably 40 ° C. or higher, in order to stabilize liquid properties at room temperature. Examples of the thermoplastic resin include poly (meth) acrylic acid, polyethylene glycol, polyethylene, polypropylene, polyvinyl acetate, polyvinyl acetal, polymethacrylic acid ester, polyacrylic acid ester, polyether, polyester, polycarbonate, cellulosic resin, Examples thereof include polyacrylonitrile, nylon, polyimide, polyamide, polyvinyl chloride, polyvinylidene chloride, polystyrene, thiocol, polysulfone, polyurethane, and copolymers of these resins. Among these, fine particles composed of poly (meth) acrylic acid, polyethylene glycol, polyethylene, polypropylene, polyvinyl acetate, polyvinyl chloride, nylon, polyurethane and the like are more preferably used. Further, fine particles formed by mixing two or more kinds of these materials, or two or more kinds of fine particles may be mixed and used.

  As the coating agent for the particles used in the thermoplastic resin coating, a conventionally known thermoplastic resin having a melting point of 40 ° C. or higher can be used without particular limitation, and more preferably, the melting point is 50 ° C. or higher. For example, acrylic ester, methacrylate ester, styrene, styrene-acrylic copolymer, styrene butadiene copolymer, acrylonitrile butadiene copolymer, polybutadiene, vinyl acetate, polyvinyl chloride, polyvinylidene chloride, ethylene vinyl acetate Homopolymerized or copolymerized resin emulsions, microemulsions, internal three-dimensionally crosslinked organic fine particles, paraffin wax, polyethylene wax, etc., with polymer olefins and monomers having hydrophilic functional groups such as amino groups, amide groups, carboxyl groups and hydroxyl groups , Carnauba wax Natural, synthetic waxes emulsion, latex, colloidal solutions, suspensions and the like.

[Final image carrier]
Printing paper can be used as the final image carrier, and conventionally known printing materials can be used. For example, various types of paper / synthetic paper can be used without particular limitation.

The paper, coated paper, there is a non-coated paper, the coated paper, 1 m ² per coated amount on one side 20 g / m ² before and after art paper, coated amount per 1 m ² on one side 10 g / m ² before and after the coated paper, 1m ² per coated amount on one side 5g / m ² before and after the light-weight coated paper, Binurikoshi, mat coated paper matte finish, Darukoto paper of dull finish, and newsprint I can list them. Non-coated paper includes printing paper A using 100% chemical pulp, printing paper B using 70% or more chemical pulp, printing paper C using 40% or more and less than 70% chemical pulp, and printing using less than 40% chemical pulp. Examples thereof include paper D, gravure paper containing mechanical pulp and subjected to calendar treatment. More details are described in detail in “Latest Paper Processing Handbook” edited by the Paper Processing Handbook Editorial Committee, published by Tech Times, “Printing Engineering Handbook” edited by the Japan Printing Society.

  As a method of transferring the image obtained on the intermediate transfer medium to the final image carrier, a method of superimposing the intermediate transfer medium and the final image carrier, and closely contacting and transferring them with heat and / or pressure is employed. A known laminator can be used for the transfer.

  Next, image formation by ink jet recording will be described. A well-known thing can be used for the inkjet printer used for this invention. Ink jet heads used in ink jet printers are large and classified into thermal head methods and piezo head methods. In the present invention, it is preferable to use a piezo head method. In addition, when the ink droplet amount is 2 pl or less, a resolution close to that of offset printing can be obtained. Therefore, the ink droplet amount is adjusted to 2 pl or less by adjusting the nozzle system, emission pressure, ink properties, and the like.

  For example, the intermediate transfer medium of the present invention can be mounted on a large-format inkjet printer (PM / MC series manufactured by Epson, Design Jet series manufactured by HP) already on sale, and use in these is a preferred embodiment. When such a commercially available large-format ink jet printer is used, after the ink jet recording, a process of transferring and peeling to the final image carrier is necessary.

  When printing paper or the like is used as a recording medium, it can be transferred onto a desired recording medium using EV-Laminator, EV-Laminator II, etc. manufactured by Konica. After the transfer in this way, the intermediate transfer medium is peeled off to obtain a recorded product that is very close to the final printed product.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not necessarily limited to the form in this Example. In addition, the following "part" represents a "mass part".

Example 1
(Pigment ink 1)
An aqueous pigment ink for inkjet was prepared according to the following formulation.

Colorant (pigment) The following description Formalin condensate of sodium creosote oil sulfonate (Damol C, manufactured by Kao Corporation)
2.5% by mass
2- (2-ethylhexyl) sulfosuccinic acid sodium salt 0.01% by mass
Glycerin 10% by mass
Ethylene glycol 13% by mass
Adjusting the remaining amount so that the total mass of falling bacteria in the air is 100g <Coloring material>
Y ink: C.I. I. Pigment Yellow 128 10% by mass (average particle size 145 nm)
M ink: C.I. I. Pigment Red122 10% by mass (average particle size 155 nm)
C ink: C.I. I. Pigment Blue 60 10% by mass (average particle size 120 nm)
K ink: C.I. I. Pigment Black 7 10% by mass (average particle size 110 nm)
(Preparation of intermediate transfer medium)
The following formulation was prepared to prepare an intermediate transfer medium coating solution.

  The prepared coating solution was applied to a support (PET film T-100 100 μm manufactured by Mitsubishi Polyester Co., Ltd.) in the combination shown in the table and dried to obtain a sample for evaluation.

(Ink absorbing layer 1)
Synthetic amorphous silica (fan seal X37B, manufactured by Tokuyama Co., Ltd.) 75 parts PVA (manufactured by Kuraray Co., Ltd.) 20 parts Polydiallyldimethylammonium chloride cationic resin (PAS-H-5L, manufactured by Nitto Boseki Co., Ltd.) 15 parts ( Ink absorbing layer 2)
Synthetic amorphous silica (fan seal X37B, manufactured by Tokuyama Co., Ltd.) 75 parts Hydrophobic resin: Polyester (PX-3035: Daiichi Kogyo Seiyaku Co., Ltd., surface tension 360 μN / cm) 20 parts Polydiallyldimethylammonium chloride cationic resin (PAS) -H-5L, manufactured by Nitto Boseki Co., Ltd.) 15 parts (ink absorbing layer 3)
Synthetic amorphous silica (fan seal X37B, manufactured by Tokuyama Co., Ltd.) 75 parts Hydrophobic resin: Modified silicone resin (SN wet 513, manufactured by San Nopco Co., Ltd., 210 μN / cm) 5 parts Hydrophobic resin: Acrylic resin (Yodosol A5801 Japan NSC) Manufactured with surface tension of 380 μN / cm) 15 parts Polydiallyldimethylammonium chloride cationic resin (PAS-H-5L, manufactured by Nitto Boseki Co., Ltd.) 15 parts (ink absorbing layer 4)
Synthetic amorphous silica (fan seal X37B, manufactured by Tokuyama) 75 parts Hydrophobic resin: Polyester (PX-3035: Daiichi Kogyo Seiyaku Co., Ltd., surface tension 360 μN / cm) 18 parts Hydrophobic resin: Unidyne TG470 (Daikin) Surface tension 100 μN / cm) 2 parts Polydiallyldimethylammonium chloride cationic resin (PAS-H-5L, manufactured by Nitto Boseki) 15 parts (ink absorbing layer 5)
Synthetic amorphous silica (fan seal X37B, manufactured by Tokuyama Co., Ltd.) 5 parts Comparative resin: polyacrylamide (C-1 manufactured by Sanyo Kasei Co., Ltd., surface tension 420 μN / cm) 20 parts Polydiallyldimethylammonium chloride cationic resin (PAS-H- 5L, manufactured by Nitto Boseki Co., Ltd.) 15 parts (hydrophobic layer 1)
Unidyne TG810 (manufactured by Daikin, surface tension 100 μN / cm) 2 parts water 90 parts IPA 8 parts (hydrophobic layer 2)
20 parts of Carnauba wax emulsion A118 (Gifu Shellac Co., Ltd., melting point 80 ° C., solid content 40% by mass, surface tension 310 μN / cm)
80 parts of pure water (intermediate layer 1)
Ethylcellulose (Etocel STD10 manufactured by Dow Chemical Company) 1 part Industrial ethyl alcohol 99 parts <Final image carrier>
Art paper: Tokuhishi Art (Made by Mitsubishi Paper Industries, 127.9 g / m ² )
High-quality paper: OK Prince fine quality (Oji Paper Co., Ltd., 90 g / m ² )
<Image formation>
An image is output as follows using an ink jet printer (PX-900G; manufactured by Seiko Epson) equipped with the ink (pigment ink) on the surface of the ink absorption layer of the intermediate transfer medium obtained as described above. It was. The appropriate amount of ink liquid was adjusted to 1.5 pl.

  After that, the recording medium and the inkjet recording surface of the intermediate transfer medium are combined and bonded using EV-Laminator II manufactured by Konica, and the intermediate transfer medium is peeled off by hand, whereby an image is recorded on the recording medium. Formed.

  Then, the following evaluation was performed. The results obtained are shown in the table.

(Image output)
In the image output, the target density of each color is set as follows, and the following main evaluation is performed based on the target density.

Y; 1.04
M; 1.53
C; 1.48
K; 1.83
Color measurement was performed using a colorimeter (Gretag Macbeth, spectrolino, keywizard) under the following conditions: Light source; D50,
Field of view; 2 ° field of view Density; ANSI T
White standard; abs
Filter; No-filter
<Evaluation>
Evaluation was performed as follows.
(Dot diameter)
The diameter of the ink drop recorded on the final image carrier was measured. If it is 25 μm or less, it can be used as an external school proof for 150 lines, and if it is 20 μm or less, it can be used as an external school proof for 175 lines.
(Black character reproduction)
Black characters of different sizes were created under the above conditions, and the number of points of characters that were accurately reproduced was recorded.
(Reproduced characters)
Under the above conditions, white characters of different sizes were created in 3C solid, and the number of points of characters that were accurately reproduced was recorded.
(Transferability)
A solid image of 100% of each color was output to the intermediate transfer medium, and the density difference when the density after sufficiently drying and the density through the first ink absorbing layer after transfer to the recording medium were measured was judged.

◎ ・ ・ ・ No density difference before and after transfer ○ ・ ・ ・ Density difference before and after transfer ± 0.05
Δ: Density difference before and after transfer ± 0.1
△ × ・ ・ Density difference before and after transfer ± 0.2
×: Density difference before and after transfer is greater than ± 0.2 (fixing property)
A solid of each color target density is prepared, and cello tape (R) and post-it (cover-up tape 652: manufactured by Sumitomo 3M) are respectively attached to the printed portion after transfer to the final image carrier, and the peeled state is visually observed below. Transcription evaluation was performed based on these criteria.

○ ・ ・ ・ No peeling with cellophane tape (R) or part of transfer part peels off △ ・ ・ ・ Part of transfer part is peeled off even with post-it × ・ ・ ・ Transfer part peeling off with post-it

  Sample No. which is outside the present invention. 1 has a problem and cannot be put into practical use. 2 to 14 are all excellent, and in particular, sample Nos. It turns out that 5-14 is excellent.

Claims (8)

An intermediate transfer medium for ink jet recording having a second ink absorbing layer and a first ink absorbing layer in this order on a support, wherein the first ink absorbing layer is formed to be peelable from the intermediate transfer medium, and An intermediate transfer medium for ink-jet recording, wherein a hydrophobic layer is provided on an upper layer of the first ink absorbing layer. An intermediate transfer medium for ink jet recording having a second ink absorbing layer and a first ink absorbing layer in this order on a support, wherein the first ink absorbing layer contains a hydrophobic resin, and the first ink absorbing layer An intermediate transfer medium for ink-jet recording, wherein the layer is formed so as to be peelable from the intermediate transfer medium. The intermediate transfer medium for ink-jet recording according to claim 1 or 2, wherein the first ink absorbing layer has a thickness of 0.2 to 5 µm. 4. The intermediate transfer medium for ink-jet recording according to claim 1, wherein the second ink absorbing layer is a void-type absorbing layer containing porous silica. 5. The method for producing an intermediate transfer medium for ink jet recording according to claim 2, 3 or 4, wherein the first ink absorbing layer is produced by applying and drying a mixture of colloidal silica and a hydrophobic resin emulsion. A method for producing an intermediate transfer medium for inkjet recording. An image forming method using the intermediate transfer medium for ink jet recording according to any one of claims 1 to 4, wherein the ink jet ink used for image formation is a water-based pigment ink, and the average particle diameter of the contained pigments Is 0.1 to 3 μm. An image forming method using the intermediate transfer medium for ink jet recording according to any one of claims 1 to 4, wherein the final image carrier and the intermediate transfer medium are printed on the intermediate transfer medium with an aqueous pigment ink. And the first ink absorbing layer is transferred to the final image carrier with at least one of heat and pressure. 8. The image forming method according to claim 6, wherein an image is formed using an inkjet image forming apparatus having ink droplets of 2 pl or less.