JP2019195923A - Recording medium - Google Patents

Abstract

To provide a recording medium having ink receiving layers on both sides, that has a good gloss uniformity feeling, no occurrence of double feeding phenomenon and excellent scratch resistance.SOLUTION: Provided is a recording medium in which an exposed part from which an ink receiving layer 1003 is exposed and an easy-sliding part 1005 in which a lubricant is discretely provided are provided on the surface thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a recording medium including an ink receiving layer that receives ink.

  As an ink jet recording medium used in an ink jet recording apparatus, a recording medium having a porous ink receiving layer on a substrate is known. In the photographic field, ink-jet recording has been replaced by silver salt photography, and ink-jet recording media are required to have high glossiness equivalent to silver salt photography. As a technique for imparting high glossiness to a recording medium used in an ink jet method, there is a cast processing method in which an ink receiving layer is pressed against a mirror drum in a wet state.

  When a plurality of recording media are set in the recording apparatus main body and continuously recorded, it is a necessary function for the recording media that adjacent recording media are separated by a paper feeding unit and conveyed one by one. The phenomenon in which the recording media are not conveyed one by one, but is conveyed at the same time is called a double feeding phenomenon, and is particularly high in a recording medium having a relatively high surface smoothness with respect to matte paper such as cast paper. This phenomenon is likely to occur in the environment.

  In recent years, there has been an increasing demand for high-speed recording in the plastic card for ink-jet recording as the application is expanded. Therefore, there is a need for an ink jet recording medium with higher performance and relatively high surface smoothness that does not cause double feeding due to stable paper conveyance by high-speed recording.

  Patent Document 1 discloses an outermost layer containing an ink receiving layer containing inorganic particles, colloidal silica, and polyethylene as a recording medium having good gloss uniformity, no occurrence of double feeding phenomenon, and excellent scratch resistance. Is provided.

JP, 2006-215467, A Japanese Patent Laid-Open No. 7-232473 Japanese Patent Laid-Open No. 8-132731 Japanese Patent Laid-Open No. 9-66664 JP-A-9-76628 Japanese Patent Laid-Open No. 61-10383

  However, in the recording medium of Patent Document 1, when an ink receiving layer is provided on one side, there is no occurrence of good gloss uniformity and double feeding phenomenon, and scratch resistance is obtained, but an ink receiving layer is provided on both sides. If provided, a plurality of sheets may be sent simultaneously. Further, when separating at the paper feeding unit, the recording surface may be scratched due to rubbing between one surface and one surface of the adjacent recording medium.

  Accordingly, an object of the present invention is to provide a recording medium having an ink receiving layer on both sides which has a good gloss uniformity, does not cause a double feed phenomenon, and has excellent scratch resistance.

  For this reason, the recording medium of the present invention is provided with an ink receiving layer capable of receiving ink provided on at least one surface of a base material and discretely provided on the surface of the ink receiving layer, and slips more than the surface of the ink receiving layer. And a highly-slidable part.

  According to the present invention, it is possible to realize a recording medium that has a good gloss uniformity, does not cause a double feed phenomenon, and has an ink receiving layer on both sides that are excellent in scratch resistance.

It is sectional drawing which showed the structure of the recording medium. It is the figure which showed the large lubricant and the small lubricant provided on the ink receiving layer. It is the cross-sectional schematic diagram which showed the easy-sliding part layer vicinity of the state with which the recording media overlapped. (A) to (b) are diagrams showing the manufacturing process of the recording medium of the present embodiment. FIG. 6 is a diagram illustrating how ink is landed on a recording medium. FIG. 3 is a schematic view of a recording medium on which ink droplets are discharged as viewed from above. It is the figure which showed the inkjet recording device which records on a recording medium. It is a block diagram which shows schematic structure of the control system of the recording device shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the structure of the recording medium of the present embodiment. The recording medium of the present embodiment includes an easy-sliding part 1005 including a large lubricant (first easy-sliding part) 1001, a small lubricant (second easy-sliding part) 1002, an ink receiving layer 1003, a base material 1004, and an ink receiving layer 1003. It is characterized by being laminated in order. The recording medium can include a base material 1004, at least one ink receiving layer, and an outermost slidable portion 1005, and between the ink receiving layer 1003 and the base material 1004, the base material 1004. A resin layer containing polyethylene for the purpose of improving smoothness may be provided.

(Easy sliding part)
The easy slip portion is provided on the surface of the ink receiving layer 1003 and can reduce friction between recording media. Further, the easy-sliding portion 1005 is not particularly limited, and a release agent that is conventionally used for release paper such as a label or a seal can be used. As the release agent, it is preferable to use at least one of a silicone resin, a long-chain alkyl resin, and a fluorine resin. The easy-slip portion 1005 is at least one selected from silicone resins, fluorine resins, polyvinyl alcohols containing long chain alkyl groups, amino alkyd resins containing long chain alkyl groups, and polyethyleneimines containing long chain alkyl groups. As a main component. The easy-sliding portion 1005 can be formed on the ink receiving layer 1003 by recording with a release agent. The easy slip portion 1005 has a structure in which release agents (lubricants) are discretely stacked on the recording surface side of the ink receiving layer 1003 as shown in FIG. More specifically, the easy-sliding portion 1005 includes a portion where the ink receiving layer 1003 is exposed on the surface of the ink receiving layer 1003 (exposed portion) and a portion where a release agent (lubricant) is arranged in a dot shape. ing. The effective thickness of the portion where the lubricant is laminated is preferably 0.1 to 50 μm. By forming such an easy-sliding portion 1005, contact between the ink receiving layers 1003 can be reduced when the recording media overlap each other.

  Furthermore, it is desirable that the effective thickness of the recorded dots is distributed in two levels. The second level means that the effective thickness T2 of the small lubricant 1002 is 1/2 or less than the effective thickness T1 of the large lubricant 1001, or 0.1 μm or more, and the maximum diameter R2 of the small lubricant 1002 is the maximum diameter of the large lubricant 1001. It is a relationship of 1/2 or less or 10 μm or more with respect to R1. Further, the area of the small lubricant 1002 is ½ or less of the area of the large lubricant 1001.

  FIG. 2 is a diagram showing a large lubricant 1001 and a small lubricant 1002 provided on the ink receiving layer 1003. Here, distances D1 and D2 between the center of the lubricant 1001 and the nearest lubricant 1001 are distances D1 and D2, and distances between the centers of the lubricant 1001 and the nearest lubricant 1002 are distances d1 and d2. Ideally, in the positional relationship between the large lubricant 1001 and the small lubricant 1002 in this embodiment, d1 = (1/2) D1 and d2 = (1/2) D2.

  FIG. 3 is a schematic cross-sectional view showing the vicinity of the easy-sliding portion in a state where the recording media overlap each other. In the formation of the easy-sliding portion 1005, a dot-like recording pattern having a recording resolution of 30 to 320 lines in the stencil recording method is formed on the ink receiving layer 1003 on one side of the recording medium having the ink receiving layer 1003 formed on both sides. The easy-sliding portion 1005 is formed so that That is, in the present invention, it is important that the release agent (lubricant) of the easy-sliding portion 1005 is discretely laminated on the recording surface of the ink receiving layer, and the release agent ( (Lubricant) is not provided. However, if the ratio of the release agent (lubricant) is too small, the lubricant property is lowered. When the lubricant property is lowered, the frictional resistance generated between the overlapping recording media waiting in an unrecorded state is increased at the time of feeding by the recording apparatus, which causes a jam phenomenon due to an unintended separation failure of the recording media.

  The area ratio of the release agent (lubricant) to the ink receiving layer 1003 is preferably 30% to 80%. If the area ratio is lower than 30%, the lubricant property becomes poor, and conversely if the area ratio is higher than 80%, there is a possibility that the absorption of the unabsorbed ink into the ink receiving layer 1003 may be insufficient. The area ratio referred to here is the area ratio of the portion where the release agent (lubricant) is provided on the surface of the ink receiving layer 1003.

  Here, “30 to 320 line recording patterns” refers to the number of lines per inch or the number of halftone dots per inch. Generally, the smaller the number of lines, the larger the pattern recording pattern, and the larger the number, the smaller the pattern recording pattern. If the number of lines of the recorded pattern is less than 30, the pattern to be recorded is large, so that each block of the part having the lubricant property and the part having the ink absorbability becomes large. If it is too large, for example, the ink receiving layer 1003 of the present invention may be undesirably spontaneously peeled off before the transfer of the ink receiving layer 1003 due to insufficient lubricity with respect to the double-sided release sheet layer. On the contrary, if the number of lines of the recorded pattern is more than 320, the pattern of the easy-sliding portion 1005 to be recorded becomes fine, so that the exposure of the ink receiving layer 1003 tends to be insufficient, and unabsorbed ink on the ink receiving layer 1003 Absorption may be insufficient.

  As a recording method used when forming the easy-sliding portion 1005, a method generally used for recording can be applied. Specific examples include letterpress recording, letterpress offset recording, stencil recording, planographic recording, engraving intaglio recording, gravure recording, screen recording, flexographic recording, and stencil recording. Of these, stencil recording is particularly preferred. The resin composition for the easy-sliding part used for recording may be any transparent composition that is not colored after recording. Moreover, you may use the material of the structure which performs a drying or hardening process by the heating by drying oven etc. suitably, or the ultraviolet irradiation by an ultraviolet irradiation device, and forming an easily-slidable part.

(Ink receiving layer)
The ink receiving layer 1003 of the present invention can receive ink droplets ejected from the ejection port of the ink jet recording apparatus by the recording medium, and maintains an image formed by the ink droplets. The configuration of the ink receiving layer 1003 will be described. The ink receiving layer 1003 of the present invention is provided on both surfaces of the substrate 1004. The film thickness of the ink receiving layer 1003 on one side of the substrate 1004 (in the case of a plurality of layers, the total film thickness of each layer) is preferably 10 μm or more and 60 μm or less from the viewpoint of ink absorbability and production suitability. More preferably, it is 15 μm or more and 45 μm or less. The ink receiving layer 1003 described above can contain inorganic particles and, if necessary, a binder, a crosslinking agent, and other additives described later.

  Hereinafter, the materials that can be contained in the ink receiving layer 1003 will be described. However, the other ink receiving layers 1003 provided on the base material (1004) may similarly contain these components, for example, in the blending ratio described later. Each can be contained. The ink receiving layer 1003 and other ink receiving layers may have the same composition or different compositions. Further, the other ink receiving layer 1003 may be, for example, an ink receiving layer known in the field of inkjet recording media. The ink receiving layer 1003 can contain inorganic particles. The ink receiving layer 1003 can contain inorganic particles as a main component.

  The main component means a component having the highest content ratio among components (components in the solid content) included in the target (here, the ink receiving layer). The inorganic particles can be, for example, particles having an average secondary particle diameter of 1 μm or less made of an inorganic material. The content of inorganic particles (solid content) (% by weight) in the ink receiving layer 1003 is preferably 50% by weight or more from the viewpoint of ink absorbability and 98% by weight or less from the viewpoint of production suitability. Furthermore, it is more preferable that it is 96 weight% or less.

  The average primary particle size of the inorganic particles is preferably 50 nm or less, more preferably 1 nm or more and 30 nm or less, and particularly preferably 3 nm or more and 10 nm or less from the viewpoint of color developability. The average primary particle diameter of the inorganic particles is the number average particle diameter of the diameters of circles having an area equal to the projected area of the primary particles of the inorganic particles when observed with an electron microscope. At this time, at least 100 points are measured.

  In the present invention, the inorganic particles are preferably used in a coating liquid for forming the ink receiving layer 1003 in a state where they are dispersed by a dispersant. The average secondary particle diameter of the inorganic particles in the dispersed state is preferably 1 nm or more and 500 nm or less from the viewpoint of ink absorbability. Furthermore, it is more preferably 1 nm or more and 300 nm or less, and particularly preferably 10 nm or more and 250 nm or less. In addition, the average secondary particle diameter of the inorganic particles in the dispersed state can be measured by a dynamic light scattering method.

In the present invention, in order to form the ink receiving layer 1003, an aqueous dispersion is prepared using one or more of the above resins and the like, and is applied on a preformed substrate 1004 and then dried. can do. Furthermore, even a simple porous material has no problem as long as the performance as a receiving layer is sufficient. When the ink receiving layer 1003 is formed, the coating amount (total coating amount) (g / m ² ) of the inorganic particles applied on the substrate 1004 is preferably 8 g / m ² or more and 45 g / m ² or less. . By setting it as the said range, it can be made easy to the film thickness (The total film thickness of each layer in the case of multiple layers) of the preferable ink receiving layer 1003.

  Examples of inorganic particles include alumina hydrate, alumina, silica, colloidal silica, titanium dioxide, zeolite, kaolin, talc, hydrotalcite, zinc oxide, zinc hydroxide, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide. , And zirconium hydroxide. These inorganic particles can be used alone or in combination of two or more as required. Among inorganic particles, it is preferable to use at least one of alumina hydrate, alumina, and silica, which can form a porous structure with high ink absorbability. These inorganic particles will be described in detail later. In addition, for oil-based jet inks, ink droplets of an ink jet recording apparatus, regardless of whether they are water-based or oil-based, including resins having swelling performance in organic solvents and various types of particles in them. As long as it has an absorptivity, any may be sufficient.

(Alumina hydrate)
As the alumina hydrate used in the ink receiving layer 1003 of the present invention, those represented by the following general formula (X) can be suitably used.
Al ₂ O _3-n (OH) _2n · mH ₂ O (general formula X)
(In general formula X, n represents 0, 1, 2, or 3 and m represents a number of 0 to 10, in which m and n are not 0 at the same time.)

In many cases, mH ₂ O represents a detachable aqueous phase that does not participate in the formation of a crystal lattice, and therefore m may not be an integer. Also, m can be zero when the alumina hydrate is heated. Furthermore, from the viewpoint of improving the purity of the active ingredient, m preferably represents a number from 0 to 5. The alumina hydrate can be produced by a known method. Specifically, for example, a method of hydrolyzing aluminum alkoxide, a method of hydrolyzing sodium aluminate, a method of neutralizing an aqueous solution of sodium aluminate by adding an aqueous solution of aluminum sulfate, aluminum chloride or the like. It is done.

  As the crystal structure of alumina hydrate, amorphous, gibbsite type, and boehmite type are known depending on the heat treatment temperature. The crystal structure of alumina hydrate can be analyzed by X-ray diffraction. Of these, boehmite type alumina hydrate or amorphous alumina hydrate is preferably used as the inorganic particles from the viewpoint of ink absorbability.

Specific examples include alumina hydrates described in Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, and the like. Moreover, as a commercial item, Dispersal HP14 and HP18 (all are a brand name, the product made from Sasol) etc. can be mentioned. These alumina hydrates can be used alone or in combination of two or more as required. Further, the specific surface area obtained by the BET method of alumina hydrate is preferably 100 m ² / g or more and 200 m ² / g or less, and 125 m ² / g or more and 175 m ² / g or less from the viewpoint of color developability. It is more preferable. Here, the BET method is a method in which a specific surface area of a sample is measured from an adsorbed amount by adsorbing molecules and ions of a known size on the sample surface. Nitrogen gas can be used as the gas adsorbed on the sample.

(alumina)
As the alumina used for the ink receiving layer 1003 of the present invention, vapor phase alumina is preferable from the viewpoint of ink absorbability. Examples of vapor phase alumina include γ-alumina, α-alumina, δ-alumina, θ-alumina, and χ-alumina. Among these, it is preferable to use γ-alumina from the viewpoint of the optical density of the image and the ink absorbability. Specific examples of vapor-phase process alumina include AEROXIDE; Alu C, Alu 130, and Alu 65 (all of which are trade names, manufactured by EVONIK).

The specific surface area determined by the BET method of the vapor phase alumina is preferably 50 m ² / g or more, more preferably 80 m ² / g or more from the viewpoint of color developability. The specific surface area determined by the BET method of the gas phase method alumina is preferably 150 meters ² / g or less from the viewpoint of ink absorbency, more preferably at most 120 m ² / g.

Further, the average primary particle diameter of vapor-phase process alumina is preferably 5 nm or more, more preferably 11 nm or more from the viewpoint of ink absorbability. In addition, the average primary particle diameter of the vapor phase alumina is preferably 30 nm or less, more preferably 15 nm or less, from the viewpoint of color developability. The alumina hydrate and alumina that can be used in the present invention are preferably mixed in the ink-receiving layer-forming coating solution as an aqueous dispersion, and an acid is preferably used as the dispersant. As the acid, it is preferable to use a sulfonic acid represented by the following general formula (Y) because an effect of suppressing bleeding of an image can be easily obtained.
R-SO ₃ H (general formula Y)
(In General Formula (Y), R represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkenyl group having 1 to 4 carbon atoms. In addition, an atom in R (for example, , A hydrogen atom H) may be substituted with at least one of an oxo group, a halogen atom, an alkoxy group, and an acyl group.

  The content of the acid in the ink-receiving layer-forming coating solution is 1.0% from the viewpoint of dispersion stability and ink absorbency with respect to a total content of 100% by weight of alumina hydrate and alumina. % Or more and 2.0% by weight or less is preferable. Moreover, it is more preferable that it is 1.3 to 1.6 weight%.

(silica)
The silica that can be used in the ink receiving layer 1003 of the present invention is roughly classified into a wet method and a dry method (gas phase method) depending on the production method. As a wet method, there is known a method in which active silica is produced by acid decomposition of silicate, and this is appropriately polymerized and coagulated and precipitated to obtain hydrous silica. On the other hand, as a dry method (gas phase method), a method using high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), silica sand and coke are heated and reduced and vaporized by an arc in an electric furnace. There is known a method of obtaining anhydrous silica by a method of oxidizing a carbon with air (arc method).

In the present invention, it is preferable to use silica obtained by a dry method (gas phase method) (hereinafter also referred to as “gas phase method silica”). This is because vapor phase method silica has a particularly large specific surface area, so that the ink absorbency is particularly high and the refractive index is low, so that transparency can be easily imparted to the ink receiving layer 1003 and good color developability is achieved. It is because it is obtained. Specifically, examples of the gas phase method silica include Aerosil (registered trademark, manufactured by Nippon Aerosil), Leolosil (registered trademark) QS type (manufactured by Tokuyama), and the like. In the invention, the specific surface area of the vapor phase silica by the BET method is preferably 50 m ² / g or more and 400 m ² / g or less, and 200 m ² / g or more and 350 m ² / g or less from the viewpoint of ink absorbability. It is more preferable.

  From the viewpoint of coating stability, the vapor phase silica is preferably used in a coating liquid for an ink receiving layer in a state where it is dispersed by a dispersant. The particle diameter of the vapor phase silica in the dispersed state is more preferably 50 nm or more and 300 nm or less from the viewpoint of color developability and ink absorbability. The particle diameter of the vapor phase silica in the dispersed state can be measured by a dynamic light scattering method.

  In the present invention, as the inorganic particles, a plurality of types selected from alumina hydrate, alumina, and silica may be mixed and used. In that case, specifically, a method in which at least two kinds selected from alumina hydrate, alumina, and silica are mixed and dispersed in a powder state to form a dispersion can be used. In the present invention, from the viewpoint of ink absorbability, it is preferable to use both alumina hydrate and vapor phase method alumina as the inorganic particles. In this case, the content of alumina hydrate (solid content) (% by weight) contained in the ink receiving layer is 1.5 times or more the content (% by weight) of vapor phase alumina. It is preferable that it is 0.0 times or less. In other words, the weight ratio of alumina hydrate to vapor-phase method alumina in the ink receiving layer (alumina hydrate content (wt%) / vapor-phase alumina content (wt%)) is 60. / 40 times or more and 90/10 times or less is preferable.

(Binder)
The ink receiving layer 1003 of the present invention preferably contains a binder from the viewpoint of production suitability. The binder means a material that can bind inorganic particles to form a film. Examples of the binder of the present invention include proteins such as casein, soybean protein and synthetic protein, various starches such as starch and oxidized starch, cellulose derivatives such as polyvinyl alcohol, carboxymethylcellulose and methylcellulose, styrene-butadiene copolymer, methyl Conventional binders generally used for coated paper such as conjugated diene polymer latex of methacrylate-butadiene copolymer, acrylic polymer latex, vinyl polymer latex such as ethylene-vinyl acetate copolymer, etc. Can be used alone or in combination of two or more.

  The binder content (solid content) in the ink receiving layer is preferably 50% by weight or less, more preferably 30% by weight or less with respect to the content of inorganic fine particles of 100% by weight from the viewpoint of ink absorbability. . Further, from the viewpoint of the binding property of the ink receiving layer, the ratio is preferably 5.0% by weight or more, and more preferably 8.0% by weight or more. When the recording medium of the present invention has a plurality of ink receiving layers 1003, the type and content of the binder in each ink receiving layer may be different or the same. .

  Among the binders described above, it is preferable to use at least one of polyvinyl alcohol and polyvinyl alcohol derivatives from the viewpoint of production suitability. Examples of the polyvinyl alcohol derivative include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, and polyvinyl acetal.

  Examples of the cation-modified polyvinyl alcohol include polyvinyl alcohol having a primary to tertiary amino group or a quaternary ammonium group as described in Patent Document 6 in the main chain or side chain of polyvinyl alcohol. preferable. By using this polyvinyl alcohol, color developability can be improved.

  Polyvinyl alcohol can be synthesized, for example, by saponifying polyvinyl acetate. The degree of saponification of polyvinyl alcohol is preferably 80 mol% or more and 100 mol% or less, and more preferably 85 mol% or more and 98 mol% or less from the viewpoint of production suitability. The degree of saponification is the ratio of the number of moles of hydroxyl groups produced by saponification reaction when saponifying polyvinyl acetate to obtain polyvinyl alcohol. In the present invention, the value measured by the method of JIS-K6726. Shall be used. The average degree of polymerization of polyvinyl alcohol is preferably 2,000 or more, more preferably 2,000 or more and 5,000 or less, from the viewpoint of production suitability. In the present invention, the average degree of polymerization is the viscosity average degree of polymerization determined by the method of JIS-K6726.

  Polyvinyl alcohol can be synthesized, for example, by saponifying polyvinyl acetate. The degree of saponification of polyvinyl alcohol is preferably 80 mol% or more and 100 mol% or less, and more preferably 85 mol% or more and 98 mol% or less from the viewpoint of production suitability. The degree of saponification is the ratio of the number of moles of hydroxyl groups produced by saponification reaction when saponifying polyvinyl acetate to obtain polyvinyl alcohol. In the present invention, the value measured by the method of JIS-K6726. Shall be used. The average degree of polymerization of polyvinyl alcohol is preferably 2,000 or more, more preferably 2,000 or more and 5,000 or less, from the viewpoint of production suitability. In the present invention, the average degree of polymerization is the viscosity average degree of polymerization determined by the method of JIS-K6726.

  When preparing the ink receiving layer coating solution, it is preferable to use the polyvinyl alcohol and the polyvinyl alcohol derivative as an aqueous solution. At that time, the solid content (solid content concentration) of the polyvinyl alcohol and the polyvinyl alcohol derivative in the aqueous solution is preferably 3% by weight or more and 20% by weight or less from the viewpoint of production suitability.

(Crosslinking agent)
The ink receiving layer 1003 of the present invention preferably further contains a crosslinking agent. Examples of the crosslinking agent include aldehyde compounds, melamine compounds, isocyanate compounds, zirconium compounds, amide compounds, aluminum compounds, boric acid, and borate. These crosslinking agents can be used alone or in combination of two or more as required. In particular, when at least one of polyvinyl alcohol and polyvinyl alcohol derivatives is used as the binder, it is preferable to use at least one of boric acid and borate among the above-described crosslinking agents.

Examples of boric acid include orthoboric acid (H ₃ BO ₃ ), metaboric acid, and diboric acid. As the borate, the water-soluble salt of boric acid is preferable. Examples of water-soluble salts of boric acid include alkali metal salts of boric acid such as sodium salt and potassium salt of boric acid; alkaline earth metal salts of boric acid such as magnesium salt and calcium salt of boric acid; boric acid And ammonium salts thereof. Among these, it is preferable to use orthoboric acid from the viewpoint of the temporal stability of the coating liquid and the effect of suppressing the occurrence of cracks.

  The amount of the crosslinking agent used can be appropriately adjusted according to the production conditions. However, the content of the crosslinking agent in the ink receiving layer (solid content of the ink receiving layer coating liquid) is 1 with respect to the binder content (100 wt%) from the viewpoint of production suitability and ink absorbability. 0.0 wt% or more and 50 wt% or less is preferable, and 5 wt% or more and 40 wt% or less is more preferable.

  Further, when the binder is polyvinyl alcohol and the cross-linking agent is at least one selected from boric acid and borate, the following is preferable from the viewpoints of productivity and ink absorbability. That is, the total content of boric acid and borate with respect to the polyvinyl alcohol content (100 wt%) in the ink receiving layer (solid content of the ink receiving layer coating solution) is 5 wt% to 30 wt%. It is preferable that it is below wt%.

  Further, when the binder is polyvinyl alcohol and the cross-linking agent is at least one selected from boric acid and borate, the following is preferable from the viewpoints of productivity and ink absorbability. That is, the total content of boric acid and borate with respect to the polyvinyl alcohol content (100 wt%) in the ink receiving layer (solid content of the ink receiving layer coating solution) is 5 wt% to 30 wt%. It is preferable that it is below wt%.

  When the recording medium of the present invention has a plurality of ink receiving layers, the type and content of the crosslinking agent in each ink receiving layer may be different or the same.

(Base material)
As the base material (1004) of the present invention, a paper or a resin film generally used as an ink jet recording paper can be applied regardless of the type of paper or film or the presence or absence of an ink jet recording layer. The paper is usually obtained by papermaking using fibers of which wood pulp is the main raw material. Moreover, the resin film can use the resin sheet shape | molded in the sheet form by the biaxial stretching process by using synthetic resins, such as a polypropylene, nylon, and polyester, as a main raw material. In addition, the main raw material means a raw material having the highest content ratio (content ratio in the solid content) among the raw materials constituting the object (here, the base material 1004).

  Examples of wood pulp include hardwood bleached kraft pulp (LBKP), hardwood bleached sulfite pulp (LBSP), softwood bleached kraft pulp (NBKP), softwood bleached sulfite pulp (NBSP), broadleaf tree-dissolved pulp (LDP), conifer tree melt Examples thereof include pulp (NDP), hardwood unbleached kraft pulp (LUKP), and softwood unbleached kraft pulp (NUKP). These can use 1 type (s) or 2 or more types as needed.

  Among wood pulps, it is preferable to use at least one of LBKP, NBSP, LBSP, NDP, and LDP having a large amount of short fiber components from the viewpoint of paper texture. The pulp is preferably a chemical pulp with few impurities (for example, sulfate pulp and sulfite pulp). Moreover, the pulp which performed the bleaching process and improved the whiteness is also preferable. Further, a compounding agent such as a sizing agent, a white pigment, a paper strength enhancer, a fluorescent brightener, a moisture retention agent, a dispersant, and a softening agent may be appropriately added to the base material of the paper.

Further, the paper density defined by JIS P 8118 in the base material of the paper is preferably 0.6 g / cm ³ or more and 1.2 g / cm ³ or less from the viewpoint of transportability at the time of recording with the recording apparatus. Further, it is more preferably 0.7 g / cm ³ or more and 1.0 g / cm ³ or less. Further, the film thickness (thickness) of the base material of the paper and the resin film is preferably 150 μm or more and 300 μm or less, and more preferably 190 μm or more and 290 μm or less, from the viewpoint of transportability at the time of recording apparatus recording. preferable.

  In addition, the film thickness of the base material 1004 can be calculated by the following method. First, a cross section of the recording medium is cut out with a microtome, and the cross section is observed with a scanning electron microscope. And the film thickness of arbitrary 100 points or more of a base material is measured, and let the average value be the film thickness of the base material 1004. The film thicknesses of the other layers in the present invention can be calculated by the same method.

(Production method)
4A to 4B are diagrams showing the manufacturing process of the recording medium of the present embodiment. First, as shown in FIG. 4A, a small lubricant 1002 is formed on one ink receiving layer 1003 of a recording medium in which an ink receiving layer 1003 is provided on both surfaces of a base material 1004 having a chrysanthemum format defined by JIS P 0202. Form a layer. In the method, the lubricant liquid 6003 is arranged in a dot-like lubricant layer 1002 through the holes of the printing plate 6002 by a stencil printing method, and a layer of the lubricant agent 1002 is formed by solidification through a drying process using hot air. Thereafter, as shown in FIG. 4 (b), the lubricant liquid 6003 is formed into a dot-like lubricant 1001 layer through the holes of the printing plate 6003, and a layer of the lubricant 1001 that is solidified through a hot air drying step is formed. To do.

  The maximum diameters R1 and R2 and effective thicknesses T1 and T2 of the small and large lubricants shown in FIGS. 1 and 2 were controlled by the thickness of the printing plates 6002 and 6003 and the size of the holes. As a finish, a sheet form in which the sheet on which the easy-sliding portion 1005 was formed was cut by a guillotine method or the like, and more specifically, a general postcard or business card size was used.

(Recording method to recording medium)
FIG. 5 is a diagram showing how ink lands on the recording medium of the present embodiment. When ink jet recording is performed on the recording medium of the present embodiment, ink droplets 7001 ejected from the ink jet recording apparatus land on the surface of the ink receiving layer 1003 to form an image. At this time, the landed ink droplet 7002 can spread and spread under the large lubricant 1001 or the small lubricant 1002.

  FIG. 6 is a schematic view of a recording medium on which ink droplets are discharged as viewed from above. The ink droplet 7002 that has landed on the ink receiving layer 1003 forms an image that is larger than the diameter of the large lubricant 1001 and the small lubricant 1002, and the image is not affected by the easy sliding portion 1005 inside the ink receiving layer 1003. Can be formed.

  FIG. 7 is a diagram illustrating an ink jet recording apparatus that performs recording on the recording medium of the present embodiment. The sheet 10003 of the recording medium is installed in a sheet feeding unit in the recording apparatus and is fed, so that the sheet is conveyed in a tensioned state by applying a surface on the side of the easy-sliding unit to each tension roller. Thereafter, the ink droplets ejected from the recording head 10002 provided between the tension rollers land on the recording medium transported immediately below to form an image. The recording medium on which the image is formed is discharged to the discharge unit. The ink jet recording apparatus includes four recording heads (K, C, M, and Y) and can perform color recording with four inks. The four recording heads (K, C, M, Y) are arranged along the conveyance direction of the recording medium.

  The recording head is arranged in the order of the recording head K for black ink, the recording head C for cyan ink, the recording head M for magenta ink, and the recording head Y for yellow ink in the conveyance direction of the recording medium. Next to this, a water applying head unit is provided.

  Each recording head (K, C, M, Y) is a so-called line head, and ejects ink over the entire area of the maximum recording width (maximum range in which recording is performed in a direction orthogonal to the recording medium conveyance direction). An exit is arranged. Further, the four recording heads K, C, M, and Y are arranged in parallel to each other.

  When the recording apparatus performs recording, only the recording medium is moved without moving each recording head, and the ink in the ejection openings is driven by driving the ejection energy generating elements provided in the ejection openings arranged in the recording head. Is discharged to the outside for recording. In this embodiment, a heater is used as an energy generating element. By energizing the heater, bubbles are generated in the liquid in the discharge port by the generated thermal energy, and the liquid is discharged from the discharge port by the pressure generated when the bubble is generated. Discharge. The discharge ports are formed on the lower surface (discharge port surface) of each recording head. The recording apparatus is provided with an ink tank 10001 for storing ink to be supplied to each recording head, a pump (not shown) for supplying ink to each recording head, and performing a cleaning operation.

  FIG. 8 is a block diagram showing a schematic configuration of a control system of the recording apparatus shown in FIG. Recording information and commands transmitted from a host device 801 such as a host PC (personal computer) are received by the CPU 800 via the interface controller 806. The CPU 800 is a central processing unit that performs various operations such as calculation, discrimination, and comparison, and controls overall control of the inkjet recording apparatus such as reception of recording information of the recording apparatus, recording operation, and handling of the recording medium. . After analyzing the received command, the CPU 800 renders the image data of each color component of the recording data by developing a bitmap on the image memory 811. In the operation process performed before recording, the capping motor 809 and the head up / down motor are driven via the output port 803 and the motor driving unit 804, and the recording heads K, C, M, and Y are moved away from the caps to the recording operation position. Move. Further, the CPU 800 controls the conveyance of the recording medium to the recording position by driving a conveyance motor 808 that conveys the recording medium via the output port 803 and the motor driving unit 804.

  When recording, in order to determine the timing (recording timing) at which ink is ejected to the recording medium conveyed at a constant speed, the leading end detection sensor detects the leading end position of the recording medium. Thereafter, in synchronization with the conveyance of the recording medium, the CPU 800 sequentially reads the recording information from the image memory, and transfers the read recording information to each recording head K, C, M, Y via the recording head control circuit 802. To do.

  The operation of the CPU 800 is executed based on a processing program stored in the program ROM 810. The program ROM 810 stores a processing program and a table corresponding to the control flow. The CPU 800 uses a work RAM 812 as a working memory. Further, the CPU 800 drives the pump motor 805 via the output port 803 and the motor drive unit 804 when performing a recovery operation for maintaining and recovering the ejection performance of each recording head and the outlet, and pressurizing the ink. And control such as suction.

  Each recording head is mounted on a carriage that moves up and down perpendicularly (in the direction of arrow B) with respect to the conveying belt surface of the conveying mechanism. Each recording head is connected to a control board (not shown) mounted on the main body by a flexible cable (not shown), and receives a signal related to ink ejection. Each recording head is connected to a power supply unit mounted on the main body via a power cable (not shown), and power is supplied from the power supply unit.

  The ejected ink is supplied to the recording head 10002 connected to the ink tank 10001 through an ink supply tube.

  These flexible cable, power cable, and ink supply tube are released from each recording head by releasing a lever (not shown) mounted on a carriage (not shown). Furthermore, each recording head can be removed by releasing a lever mounted on the carriage, and can be replaced as necessary.

  In the ink jet recording apparatus of the present embodiment having the above-described configuration, when receiving a signal for recording, the CPU 800 controls a head up / down motor (not shown) to lower the carriage, and each of the recording heads mounted on the carriage. The position is determined as the recording operation position. The recording operation position is an interval suitable for performing the recording operation, that is, the interval between the recording medium conveyed to the position facing the ejection port surface of the recording head, that is, ink is appropriately landed on the recording medium. Therefore, the position is a suitable interval.

  When a detection signal is output from the mark detection sensor after the conveyance of the recording medium is started, the CPU 800 that has received the detection signal determines that the recording medium being conveyed has reached under the black recording head K. . Here, the CPU 800 controls the recording head control circuit 802 to discharge black ink from the recording head K based on the recording information sent from the host PC 801. Similarly, the CPU 800 ejects ink of each color based on the recording information in the order of the recording head C, the recording head M, and the recording head Y. In this recording operation, the CPU 800 controls the transport speed of the transport belt and the ink ejection timing based on the signal from the encoder detection sensor B. The recording medium on which recording has been completed is conveyed downstream from the discharge side shaft and discharged.

  Hereinafter, the present invention will be described more specifically with reference to production examples and comparative examples. However, the present invention is not limited to these examples. Further, “parts” and “%” in the examples indicate parts by weight and% by weight, respectively, unless otherwise specified.

[Example 1]
An example of the recording medium of the present invention is characterized by comprising at least an easy-sliding portion 1005, an ink receiving layer 1003, and a base material 1004, as schematically shown in FIG.

(Formation of easy-slip part)
As the recording medium, a recording medium “GP-501 manufactured by Canon Inc.” having a glossy ink receiving layer on one side was used. Next, an aminoalkyd resin (Tesfine 305, manufactured by Hitachi Chemical Co., Ltd.) containing a long-chain alkyl group as a lubricant is applied using a stencil printing machine (made by Riso Kagaku Co., Ltd.) and a printing plate (T-300 mesh). Then, it was dried with hot air to provide an easy-sliding part, and an ink jet recording medium having the easy-sliding part was obtained. An easy-sliding part coating solution prepared by dissolving 20% by weight of the resin with respect to the solvent of aminoalkyd resin containing a long chain alkyl group (Tesfine 305, manufactured by Hitachi Chemical Co., Ltd.), mixing and stirring the solution It formed with the following method with the stencil printer.

  In other words, the number of lines / 300 lines, printed patterns / dots (circular shape with a maximum diameter of 25.4 μm), and the area ratio of the formed easy-slip part is 30% using a resin printing plate. Printing was performed so that the effective coating thickness of the part was 8 μm. After printing, it was dried and cured with a warm air heater to form an easy-sliding portion. Next, the effective coating thickness after drying the coating liquid of the lubricant with the stencil printing machine and the printing plate (T-420 mesh) is set to 30 μm on the surface on which the small easy slip portion is formed. Printed. After printing, it was dried and cured with a warm air heater to form a large sliding portion. The recording medium of the present invention was obtained by the above manufacturing process.

[Example 2]
A recording medium having an easy-sliding portion having a configuration in which the ink receiving layer was partially exposed was obtained in the same manner as in Example 1 except that the printing plate having 150 lines was used.

[Example 3]
In the formation of the slippery part, a slippery part having a second configuration in which the ink receiving layer was partially exposed was formed in the same manner as in Example 1 except that a printing plate having an area ratio of 35% was used. A recording medium was obtained.

[Example 4]
In the formation of the slippery part, a recording medium on which a slippery part having a configuration in which the ink receiving layer is partially exposed is formed in the same manner as in Example 1 except that a printing plate having an area ratio of 70% is used. Obtained.

[Comparative Example 1]
A recording medium similar to that of Example 1 was obtained except that the easy slip portion was not formed.

[Comparative Example 2]
A recording medium similar to that of Example 1 was obtained except that the easy slip portion was solid-printed in the formation of the easy slip portion.

[Reference Example 1]
A recording medium similar to that in Example 1 was obtained except that a printing plate having an area ratio of 10% was used in forming the easy-sliding portion.

[Reference Example 2]
In the formation of the slippery part, the same recording medium as in Example 1 was obtained except that the effective coating thickness of the adhesive paste was printed to 4 μm and the slippery part was provided.

<Evaluation>
Using each recording medium obtained above, the ink receiving layer was transferred from the recording medium onto a commercially available PVC card as shown in FIG. 6, and then printed on the ink receiving layer transferred to the PVC card by an ink jet method.

  Table 1 is a table summarizing the evaluation results of evaluating the image degradation and the floating of the bonding in the recording medium of each example. The same image with many solid coating portions was formed on each of the recording media produced in Examples 1 to 5 using an ink jet recording apparatus using an aqueous pigment ink. Immediately after forming the image, the transfer sheets prepared in Examples, Comparative Examples, and Reference Examples were pasted onto the PVC card. Then, the recorded image was visually observed and the contour portion was observed with a magnifying glass, and whether or not the image was deteriorated was relatively evaluated in three stages of ◯, Δ, and X. In addition, relative evaluation was performed in three stages of ○, Δ, and × to determine whether floating occurred in the bonded state.

1001 Large lubricant 1002 Small lubricant 1003 Ink receiving layer 1004 Base material 1005 Easy sliding portion

Claims (10)

An ink receiving layer capable of receiving ink provided on at least one surface of the substrate;
A slippery portion provided discretely on the surface of the ink receiving layer, and having a higher slidability than the surface of the ink receiving layer;
A recording medium comprising:   The easy-sliding part includes a first easy-sliding part and a second easy-sliding part, and the thickness of the second easy-sliding part is ½ or less of the thickness of the first easy-sliding part. The recording medium according to claim 1.   3. The recording medium according to claim 2, wherein an area of the second easy-to-slide portion is equal to or less than ½ of an area of the first easy-to-slip portion.   The recording medium according to claim 1, wherein an area ratio of the easy-sliding portion to the ink receiving layer is 30% to 80%.   The easy slip layer is at least one selected from silicone resins, fluorine resins, polyvinyl alcohols containing long chain alkyl groups, amino alkyd resins containing long chain alkyl groups, and polyethyleneimines containing long chain alkyl groups. The recording medium according to any one of claims 1 to 4, wherein the recording medium contains a seed polymer as a main component.   The recording medium according to any one of claims 1 to 5, wherein the recording medium is in the form of a single sheet.   The recording medium according to claim 1, wherein the ink receiving layer contains inorganic fine particles.   The recording medium according to claim 7, wherein the ink receiving layer contains a binder, a crosslinking agent, and an additive.   9. The recording medium according to claim 8, wherein the content of the binder in the ink receiving layer is 50% by weight or less with respect to the content of inorganic fine particles of 100% by weight.   The recording medium according to claim 1, wherein the ink receiving layer is capable of receiving ink droplets ejected from an ink jet recording apparatus.