Printing method

Abstract

To provide a printing method which allows for printing images with superior scratch resistance on coated paper using a toner, and to provide prints obtained thereby.SOLUTION: Disclosed herein are: a method of printing images on coated paper using a toner, where a difference in surface tension between the coated paper and the toner is in a range of 15.0 to 33.0 mN / m, inclusive; and prints obtained through the method.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to printed matter suitable for commercial printed matter such as high-grade art books, photo books, magazine covers, posters, frontispieces, calendars, magazine texts, textbooks, flyers, and various catalogs, and to a printing method thereof. [Background technology]

[0002] 2. Description of the Related Art In recent years, from the viewpoint of achieving high image quality, coated paper, the surface of which is coated with a paint, has been widely used as printing paper, particularly in the field of commercial printing.

[0003] Patent Document 1 describes a toner with a core-shell structure capable of exhibiting good fixing strength on coated paper, which has difficulty retaining toner images compared to plain paper, and which has a core containing at least a resin and a shell formed by coating the surface of the core with a resin, the shell containing at least a copolymer formed using a styrene-based monomer and a diene-based monomer, the copolymer formed using at least a styrene-based monomer and a diene-based monomer having a ratio of styrene-based monomer of 55% or more and 90% or less and a ratio of diene-based monomer of 10% or more and 45% or less. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-150229 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when printing with toner, coated paper has a smaller amount of cellulose on the printed surface compared to paper that has not been coated with paint (uncoated paper), making it difficult for hydrogen bonds to form between the cellulose on the paper and the toner. This means that compared to inkjet printing, in which the ink soaks into the paper, there are issues with the abrasion resistance of the printed image, such as the toner peeling off due to papers rubbing against each other.

[0006] The present invention relates to a printing method capable of printing an image having excellent abrasion resistance on coated paper using a toner, and to a printed matter obtained by the printing method. [Means for solving the problem]

[0007] The present invention relates to [1] A method for printing an image on coated paper using a toner, the difference between the surface tension of the coated paper and the surface tension of the toner being 15.0 mN / m or more and 33.0 mN / m or less; and [2] A printed matter obtained by the method described in [1] above. Regarding. Effect of the Invention

[0008] The method of the present invention makes it possible to print images with excellent abrasion resistance on coated paper using a toner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A major feature of the present invention is that when printing an image on coated paper using toner, a toner and coated paper having a difference in surface tension within a specified range are used, thereby producing a printed matter with excellent abrasion resistance.

[0010] Usually, to improve the abrasion resistance of a printed image, the surface tension difference between the paper surface and the toner is reduced, which improves the affinity between the paper and the toner and improves the adhesiveness, thereby suppressing the interfacial peeling between the paper and the toner layer (image). However, the present inventors have discovered a finding that is unexpected even for those skilled in the art that, in printing on coated paper, a printed matter with excellent abrasion resistance can be obtained when the surface tension difference between the coated paper and the toner is a specific value or more. This is believed to be because if the adhesive force between the coated paper and the toner is too strong, the cohesive failure of the toner is more likely to occur than interfacial peeling. It is presumed that by selecting a toner and a coated paper with a surface tension difference within a specified range, the adhesiveness between the toner and the paper can be appropriately controlled, resulting in good abrasion resistance. In this technical field, it is not common to pay attention to the surface tension of something with irregularities such as paper. In particular, in the case of uncoated paper, the paper surface has large irregularities and a large anchor effect, so peeling is unlikely to occur at the interface between the paper and the toner layer, and deterioration of image quality due to abrasion is mainly due to cohesive failure of the toner layer. Therefore, in the case of uncoated paper, the difference in surface tension with the toner has almost no effect on abrasion resistance.

[0011] The difference between the surface tension of the coated paper and the surface tension of the toner is 15.0 mN / m or more, preferably 17.0 mN / m or more, more preferably 20.0 mN / m or more, from the viewpoint of preventing cohesive failure of the toner layer, and is 33.0 mN / m or less, preferably 32.8 mN / m or less, more preferably 32.6 mN / m or less, from the viewpoint of preventing peeling of the toner layer.

[0012] The toner used in the present invention is not particularly limited as long as the difference in surface tension with the coated paper is within a predetermined range, but it is preferable that the toner contains a binder resin and a colorant, like a general toner.

[0013] The binder resin is not particularly limited as long as it is a resin used as a binder resin for toner, and examples thereof include polyester resin, vinyl resin such as styrene-acrylic resin, epoxy resin, polycarbonate, polyurethane, and composite resin containing two or more of these resins. In the present invention, from the viewpoint of suppressing cohesive failure of the toner, polyester resins such as polyester resin and composite resin having polyester resin and styrene resin are preferred, and polyester resin is more preferred.

[0014] The polyester resin is preferably a polycondensation product of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing an aromatic dicarboxylic compound.

[0015] The alkylene oxide adduct of bisphenol A has the formula (I):

[0016] [ka]

[0017] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y are the average number of moles of alkylene oxide added, each of which is a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less.) Examples of the compound include an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A.

[0018] The content of the alkylene oxide adduct of bisphenol A represented by formula (I) in the alcohol component is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%.

[0019] Examples of other alcohol components include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, 2,3-butanediol, and neopentyl glycol; and trihydric or higher alcohols such as bisphenol A, hydrogenated bisphenol A, and glycerin.

[0020] Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms. Of these, terephthalic acid is preferred.

[0021] The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 55 mol% or more, more preferably 60 mol% or more, even more preferably 65 mol% or more, and is preferably 100 mol% or less, more preferably 90 mol% or less, even more preferably 80 mol% or less.

[0022] Examples of other carboxylic acid components include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid which may be substituted with a hydrocarbon group having from 1 to 20 carbon atoms, adipic acid, and sebacic acid, trivalent or higher carboxylic acid compounds such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and pyromellitic acid, anhydrides of these acids, and alkyl esters in which the alkyl group has from 1 to 3 carbon atoms.

[0023] In addition to the alcohol component and the carboxylic acid component, polyethylene terephthalate (PET) may be used. PET, or ethylene glycol and terephthalic acid produced by depolymerization of a portion of it, are used as raw material monomers in a polycondensation reaction and are incorporated into polyester resin. PET is an equimolar polycondensation product of ethylene glycol and terephthalic acid, and the ethylene glycol and terephthalic acid that make up PET are regarded as the alcohol component and the carboxylic acid component, respectively.

[0024] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monovalent carboxylic acid compound.

[0025] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and the carboxylic acid component.

[0026] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.75 or more, and is preferably 1.2 or less, more preferably 1.15 or less.

[0027] The polyester resin can be produced, for example, by polycondensing the raw material monomers, that is, an alcohol component and a carboxylic acid component, in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and further, if necessary, in the presence of an esterification promoter, a radical polymerization inhibitor, etc., at a temperature of preferably 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0028] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolaminate), and tin compounds are preferred. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, relative to 100 parts by mass of the raw material monomer. Examples of the esterification promoter include gallic acid, etc. The amount of the esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, relative to 100 parts by mass of the raw material monomer. Examples of the radical polymerization inhibitor include tert-butylcatechol, etc. The amount of the radical polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, relative to 100 parts by mass of the raw material monomer.

[0029] In the present invention, the polyester resin may be modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins grafted or blocked with phenol, urethane, epoxy, or the like, by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like.

[0030] The polyester resin in the composite resin is the same as the polyester resin described above.

[0031] The styrene-based resin in the composite resin is an addition polymer of raw material monomers containing at least styrene or a styrene derivative such as α-methylstyrene or vinyltoluene (hereinafter, styrene and styrene derivatives are collectively referred to as "styrene compounds").

[0032] The content of the styrene compound, preferably styrene, in the raw material monomer of the styrene-based resin is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more from the viewpoint of storage stability, and is preferably 95% by mass or less, more preferably 93% by mass or less, and even more preferably 90% by mass or less from the viewpoint of low-temperature fixability.

[0033] The styrene-based resin may also contain an alkyl (meth)acrylate ester as a raw material monomer. Examples of the alkyl (meth)acrylate ester include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, and (iso)stearyl (meth)acrylate. It is preferable to use one or more of these. In this specification, "(iso)" means that both the case where this group is present and the case where it is not present are included, and the case where these groups are not present indicates that it is normal. In addition, "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, or both.

[0034] The number of carbon atoms in the alkyl group in the (meth)acrylic acid alkyl ester as a raw material monomer of the styrene-based resin is, from the viewpoint of improving the low-temperature fixing property of the toner, preferably 4 or more, more preferably 7 or more, and even more preferably 8 or more, and from the viewpoint of the storage stability of the toner, is preferably 18 or less, more preferably 12 or less, and even more preferably 10 or less. The number of carbon atoms in the alkyl ester refers to the number of carbon atoms derived from the alcohol component constituting the ester.

[0035] The raw material monomers for the styrene-based resin may include raw material monomers other than styrene compounds and (meth)acrylic acid alkyl esters, for example, ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylates such as dimethylaminoethyl (meth)acrylate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone.

[0036] The addition polymerization reaction of raw material monomers for the styrene-based resin can be carried out by a conventional method in the presence of a polymerization initiator such as dibutyl peroxide or dicumyl peroxide, a chain transfer agent, a crosslinking agent, or the like, in the presence of an organic solvent or without a solvent. The temperature conditions are preferably 110° C. or higher, more preferably 140° C. or higher, and preferably 200° C. or lower, more preferably 170° C. or lower.

[0037] When an organic solvent is used in the addition polymerization reaction, xylene, toluene, methyl ethyl ketone, acetone, etc. can be used. The amount of the organic solvent used is preferably 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the raw material monomer of the styrene-based resin.

[0038] The composite resin is more preferably a resin chemically bonded by a covalent bond via a dual-reactive monomer capable of reacting with both the raw material monomer of the polyester resin and the raw material monomer of the styrene-based resin.

[0039] The bireactive monomer is preferably a compound having at least one functional group selected from the group consisting of hydroxyl group, carboxyl group, epoxy group, primary amino group and secondary amino group, preferably hydroxyl group and / or carboxyl group, more preferably carboxyl group and ethylenically unsaturated bond in the molecule, more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid and maleic anhydride, and from the viewpoint of reactivity of polycondensation reaction and addition polymerization reaction, more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid and fumaric acid, and more preferably acrylic acid. However, when used together with a radical polymerization inhibitor, a polyvalent carboxylic acid compound having an ethylenically unsaturated bond such as fumaric acid functions as a raw material monomer for polyester resin. In this case, fumaric acid etc. is not a bireactive monomer but a raw material monomer for polyester resin.

[0040] The amount of the bireactive monomer used is preferably 1 mol or more, more preferably 2 mol or more, and even more preferably 3 mol or more, relative to 100 mol of the total of the alcohol components of the polyester resin, from the viewpoint of increasing the dispersibility of the styrene resin and the polyester resin and improving the durability of the toner, and is preferably 30 mol or less, more preferably 20 mol or less, from the viewpoint of low-temperature fixability. The amount of the bireactive monomer used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of the raw material monomers of the styrene resin, from the viewpoint of increasing the dispersibility of the styrene resin and the polyester resin and improving the durability of the toner, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, from the viewpoint of low-temperature fixability. Here, the total amount of the raw material monomers of the styrene resin includes the radical polymerization initiator.

[0041] The composite resin can be produced, for example, by a method including step (A) of polycondensation reaction with raw material monomers of polyester resin and step (B) of addition polymerization reaction with raw material monomers of styrene-based resin. (i) Step (B) may be carried out after step (A), (ii) Step (A) may be carried out after step (B), or (iii) Step (A) and Step (B) may be carried out simultaneously. It is preferable to use the bireactive monomer together with the raw material monomers of the styrene-based resin.

[0042] In the method (i), after step (B), the reaction temperature may be increased again, and if necessary, a raw material monomer of the amorphous polyester resin having three or more valences, which serves as a crosslinking agent, may be added to the reaction system to further promote the polycondensation reaction of step (A) or the reaction with the bireactive monomer. Also, instead of carrying out the polycondensation reaction in step (A), a prepolymerized polycondensation resin may be used. When steps (A) and (B) are carried out in parallel, a mixture containing raw material monomers for the styrene resin may be dropped into a mixture containing raw material monomers for the polyester resin to cause the reaction.

[0043] It is preferable that the step (A) and the step (B) are carried out in the same vessel.

[0044] The mass ratio of the polyester resin to the styrene-based resin in the composite resin (polyester resin / styrene-based resin) is preferably 60 / 40 or more, more preferably 70 / 30 or more, from the viewpoint of low-temperature fixability, and is preferably 97 / 3 or less, more preferably 93 / 7 or less, and even more preferably 90 / 10 or less, from the viewpoint of durability. In the above calculation, the mass of the polyester resin is the mass of the raw material monomers of the polyester resin used minus the amount of reaction water (calculated value) dehydrated by the polycondensation reaction, and the amount of the bireactive monomer is included in the amount of raw material monomers of the polyester resin. The amount of the styrene-based resin is the total amount of the raw material monomers of the styrene-based resin.

[0045] The softening point of the polyester resin, preferably the polyester resin, is preferably 90° C. or higher, more preferably 100° C. or higher, from the viewpoint of storage stability, and is preferably 160° C. or lower, more preferably 140° C. or lower, from the viewpoint of low-temperature fixability.

[0046] From the viewpoint of low-temperature fixing property and fixing width, the polyester resin may be composed of resins having different softening points. The difference in softening point between the two resins is preferably 10° C. or more, more preferably 20° C. or more, and is preferably 60° C. or less, more preferably 50° C. or less.

[0047] The polyester resin having a higher softening point (resin H) has a softening point of preferably 110°C or higher, more preferably 120°C or higher, from the viewpoint of fixing width, and preferably 180°C or lower, more preferably 160°C or lower, from the viewpoint of low-temperature fixing ability.

[0048] Furthermore, the softening point of the polyester resin (resin L) having a lower softening point is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher from the viewpoint of storage stability, and is preferably 130°C or lower, more preferably 125°C or lower, and even more preferably 120°C or lower from the viewpoint of low-temperature fixability.

[0049] The mass ratio of resin H to resin L (resin H / resin L) is preferably 10 / 90 or more, more preferably 20 / 80 or more, even more preferably 30 / 70 or more, and preferably 90 / 10 or less, more preferably 80 / 20 or less, even more preferably 70 / 30 or less.

[0050] The glass transition temperature of the polyester resin, preferably the polyester resin, is preferably 40° C. or higher, more preferably 50° C. or higher, from the viewpoint of storage stability, and is preferably 80° C. or lower, more preferably 70° C. or lower, and even more preferably 65° C. or lower, from the viewpoint of low-temperature fixability.

[0051] The acid value of the polyester resin, preferably the polyester resin, is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, from the viewpoint of low-temperature fixability, and is preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, even more preferably 20 mgKOH / g or less, and even more preferably 15 mgKOH / g or less, from the viewpoint of moisture absorption.

[0052] In addition, the content of the binder resin in the toner is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and is preferably less than 100% by mass, more preferably 98% by mass or less, even more preferably 95% by mass or less.

[0053] The content of the polyester resin in the toner is preferably 60% by mass or more, more preferably 70% by mass or more, and is preferably less than 100% by mass, more preferably 98% by mass or less, and even more preferably 95% by mass or less. The content of the polyester resin includes the amount of the polyester resin contained in the composite resin.

[0054] As the colorant, dyes, pigments, magnetic materials, etc. used as colorants for toners can be used. For example, carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, etc. can be mentioned. In the present invention, the toner may be either a black toner or a color toner.

[0055] From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0056] The toner of the present invention may contain additives such as a release agent, a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver, in addition to the binder resin and the colorant.

[0057] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more.

[0058] The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, from the viewpoint of toner transferability, and is preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 120° C. or lower, and even more preferably 110° C. or lower, from the viewpoint of low-temperature fixability.

[0059] The content of the release agent is, from the viewpoint of the low-temperature fixing property and offset resistance of the toner and the viewpoint of dispersibility in the binder resin, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, relative to 100 parts by mass of the binder resin, and is preferably 10 parts by mass or less, and more preferably 8 parts by mass or less.

[0060] The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.

[0061] Examples of the positively charged charge control agent include nigrosine dyes such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron N-01", "Bontron N-04", "Bontron N-07", "Bontron N-09", and "Bontron N-11" (all manufactured by Orient Chemical Industries Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX Examples of such resins include "VP435" (manufactured by Clariant), etc.; polyamine resins, such as "AFP-B" (manufactured by Orient Chemical Industry Co., Ltd.); imidazole derivatives, such as "PLZ-2001" and "PLZ-8001" (both manufactured by Shikoku Kasei Corporation); and styrene-acrylic resins, such as "FCA-701PT" and "FCA-201-PS" (manufactured by Fujikura Kasei Co., Ltd.).

[0062] Examples of the negatively chargeable charge control agent include metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" (all manufactured by Orient Chemical Industry Co., Ltd.), "Aizenspiron Black TRH", and "T-77" (manufactured by Hodogaya Chemical Industry Co., Ltd.); metal compounds of benzilic acid compounds such as "LR-147" and "LR-297" (all manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds such as "Bontron E-81", "Bontron E-84", "Bontron E-88", and "Bontron E-304" (all manufactured by Orient Chemical Industry Co., Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Industry Co., Ltd.); copper phthalocyanine dyes; and quaternary ammonium salts such as "COPY CHARGE NX VP434 (Clariant), nitroimidazole derivatives, and organometallic compounds.

[0063] From the viewpoint of the charging stability of the toner, the content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0064] The toner may be a toner obtained by any of the conventionally known methods such as a melt kneading method, an emulsion aggregation method, a polymerization method, etc., and may also be a toner having a core-shell structure, but from the viewpoint of color development of printed images, a pulverized toner by a melt kneading method is preferred. In the case of a pulverized toner by a melt kneading method, for example, raw materials such as a binder resin, a colorant, and, if necessary, a release agent and a charge control agent are uniformly mixed in a mixer such as a Henschel mixer, and then melt kneaded in an internal kneader, a single-screw or twin-screw extruder, an open roll type kneader, etc., and cooled, pulverized, and classified to produce the toner. The release agent may be used together with the raw material monomer when producing the polyester resin, and may be added internally to the resin.

[0065] In order to improve the transferability, it is preferable to use an external additive in the toner. Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles, and two or more kinds may be used in combination. Among these, silica is preferable, and from the viewpoint of the transferability of the toner, hydrophobic silica that has been hydrophobized is more preferable.

[0066] Examples of hydrophobic treatment agents for hydrophobizing the surfaces of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0067] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle size of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

[0068] From the viewpoint of the electrostatic chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the toner particles before being treated with the external additive, and is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less.

[0069] The volume median particle size (D 50 ) is preferably 3 μm or more, more preferably 4 μm or more, and is preferably 15 μm or less, more preferably 10 μm or less. 50 ) refers to the particle size at which the cumulative volume frequency calculated by volume fraction is 50% calculated from the smallest particle size. In addition, when the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is regarded as the volume median particle size of the toner.

[0070] As described above, the surface tension of the toner is not particularly limited as long as the difference in surface tension with the coated paper is within a predetermined range, but from the viewpoint of suppressing cohesive failure of the toner, it is preferably 30.0 mN / m or more, more preferably 33.0 mN / m or more, and even more preferably 35.0 mN / m or more, and from the viewpoint of wettability to paper, it is preferably 45.0 mN / m or less, more preferably 42.0 mN / m or less, and even more preferably 40.0 mN / m or less.

[0071] The surface tension of the toner can be adjusted by the raw materials, the manufacturing method, etc. For example, raw materials effective for increasing the surface tension include low molecular weight binder resins, and raw materials effective for decreasing the surface tension include crystalline polyester resins and waxes. As a manufacturing method for the toner, the melt-kneading and pulverizing method is effective for decreasing the surface tension.

[0072] The printing method using toner is not particularly limited as long as it is a method for forming an image on paper by electrophotography, electrostatic recording, electrostatic printing or the like, but specific examples include methods including a charging step of charging a photoconductor, an exposure step of exposing the photoconductor to light, a developing step of attaching toner to the electrostatic latent image formed on the photoconductor to form a toner image (image), a transfer step of transferring the formed toner image to a recording medium, and a fixing step of fixing the transferred toner image to the recording medium by heat fixing or the like.

[0073] The development method may be either a one-component development method or a two-component development method.

[0074] Coated papers are generally classified according to the base paper and the amount of pigment applied, as follows:

[0075] [Table 1]

[0076] The coated paper used in the present invention is not particularly limited as long as the difference in surface tension with the toner falls within a specified range, but examples of pigments coated on the surface of the paper include calcium carbonate (CaCO3), kaolin (Al4Si4O10(OH)8), talc (Mg3Si4O10(OH)2), etc. Of these, calcium carbonate is widely used in commercial printing because of its low cost and high whiteness.

[0077] From the viewpoint of whiteness, the surface tension of the coated paper is preferably 30.0 mN / m or more, more preferably 40.0 mN / m or more, and even more preferably 48.0 mN / m or more, and from the viewpoint of paper stiffness, it is preferably 90.0 mN / m or less, more preferably 80.0 mN / m or less, and even more preferably 75.0 mN / m or less.

[0078] On the other hand, from the viewpoint of ink wettability, the surface tension of the coated paper is preferably 20.0 mN / m or more, more preferably 30.0 mN / m or more, and even more preferably 40.0 mN / m or more, and from the viewpoint of suppressing ink penetration, it is preferably 75.0 mN / m or less, more preferably 70.0 mN / m or less, and even more preferably 60.0 mN / m or less.

[0079] Printed matter using coated paper is suitable for commercial printing such as high-end art books, photo books, magazine covers, posters, frontispieces, calendars, magazine texts, textbooks, flyers, and various catalogs. EXAMPLES

[0080] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Physical properties of resins and the like can be measured by the following methods.

[0081] [Softening points of resin and toner] Using a flow tester "CFT-500D" (Shimadzu Corporation), 1g of sample is heated at a temperature increase rate of 6℃ / min while applying a load of 1.96MPa with the plunger, and extruding the sample from a nozzle with a diameter of 1mm and a length of 1mm. The amount of plunger descent of the flow tester is plotted against the temperature, and the temperature at which half of the sample has flowed out is taken as the softening point.

[0082] [Glass Transition Temperature of Resin and Toner] Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated to 200°C, and cooled from that temperature to 0°C at a rate of 10°C / min. The sample is then heated at a rate of 10°C / min and the endothermic peak is measured. The glass transition temperature is the temperature at the intersection of the extension of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising part of the peak to the top of the peak.

[0083] [Acid value of resin] Measure based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixture specified in JIS K 0070 to a mixture of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0084] [Melting point of release agent] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated to 200°C at a heating rate of 10°C / min, and cooled to -10°C at a heating rate of 5°C / min. The sample is then heated to 180°C at a heating rate of 10°C / min and measured, and the maximum endothermic peak temperature is taken as the melting point.

[0085] [Volume Median Particle Size and CV Value of Resin Particles, Colorant Particles, and Release Agent Particles] (1) Measuring device: Laser diffraction type particle size measuring device "LA-920" (manufactured by Horiba, Ltd.) (2) Measurement conditions: Put the sample dispersion in a measurement cell, add distilled water, and calculate the volume median particle size (D) from the particle size distribution obtained at a concentration that brings the absorbance into the appropriate range. 50 ) and volume average particle size (D V ) is obtained. The CV value (particle size distribution) is calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume average particle size) x 100

[0086] [Solid Content Concentration of Resin Particle Dispersion, Colorant Particle Dispersion, and Release Agent Particle Dispersion] Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), measure the moisture (mass%) of 5 g of the measurement sample at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 minutes, moisture content fluctuation range 0.05%). The solid content concentration is calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0087] [Volume Median Particle Size of Agglomerated Particles] Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50μm Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size (D 50 ) is required.

[0088] [Circularity of fused particles] The circularity of the fused particles is measured under the following conditions. Measurement equipment: Flow-type particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: A dispersion of fused particles is prepared by diluting with deionized water so that the solid content concentration is 0.001% by mass or more and 0.05% by mass or less. Measurement mode: HPF measurement mode

[0089] [Volume median particle size of toner (D 50 ) and CV value The measuring device, aperture diameter, analysis software, and electrolyte used were the same as those used in the measurement of the volume median particle diameter of the agglomerated particles described above, and the rest were measured as follows. Dispersion liquid: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB (hydrophile-lipophile balance) = 13.6) is dissolved in the electrolyte to obtain a dispersion liquid with a concentration of 5 mass %. Dispersion conditions: 10 mg of the dried measurement sample is added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser (machine name: US-1, manufactured by SND Co., Ltd., output: 80 W). Then, 25 mL of the electrolyte is added, and further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles could be measured in 20 seconds. Then, 30,000 particles were measured, and the volume median particle size (D 50 ) and volume average particle size (D V ) is obtained. The CV value (particle size distribution) is calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume average particle size) x 100

[0090] [Average particle size of external additives] The average particle size refers to the number-average particle size, and is calculated by measuring the particle sizes (average of major and minor diameters) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these by number.

[0091] [Surface tension of paper and toner] The surface tension of paper and toner is calculated according to the following method, based on the contents described in J. Phys. Chem. C 2012, 116, 14568-14574. Measurements are performed using paper cut into 1 cm square pieces. 1.5 g of toner is placed in a pressurizer (diameter 25 mm), the surface is smoothed, and then pressed to obtain a disk-shaped molded product (pellet-shaped toner) with a diameter of 25 mm and a thickness of approximately 2 mm, which is used as the measurement sample. The pressurization operation is performed twice for 10 seconds at 40 MPa, with the sample being inverted for the second pressurization. The surface tension of the pellet-shaped toner can be considered to be equivalent to the surface tension of the printing surface. At 25°C, 2μL of ion-exchanged water and diiodomethane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) are dropped onto the surface of paper or toner, and the contact angle is measured after 5 seconds for paper and 30 seconds for toner using a fully automatic contact angle meter DM-701 (manufactured by Kyowa Interface Science Co., Ltd.). The average values ​​of the five measurements with each solvent are taken as θw (average value of contact angle measured with ion-exchanged water) and θd (average value of contact angle measured with diiodomethane), respectively. Using the Young-Owens equation, the obtained θw is substituted into the following formula (1), and θd is substituted into the following formula (2), and the non-polar component term (γa) and polar component term (γb) of the surface tension of each label are calculated from formulas (1) and (2). Then, the surface tension (γ) is calculated from the obtained γa and γb according to the following formula (3).

[0092] Equation (1):(γa×γaw) 1 / 2 +(γb×γbw) 1 / 2 =0.5×γw×(1+cosθw) Here, the surface tensions of water γw, γaw, and γbw are set to γaw = 21.8 mN / m, γbw = 51.0 mN / m, and γw = 72.8 mN / m, as described in Owens, DK and Wendt, RC, J. Appl. Polym. Sci. 1969, 13, 1741-1747.

[0093] Equation (2):(γa×γad) 1 / 2 +(γb×γbd) 1 / 2 =0.5×γd×(1+cosθd) Here, the surface tensions γd, γad, and γbd of diiodomethane are set to γad = 49.5 mN / m, γbd = 1.3 mN / m, and γd = 50.8 mN / m, as described in Owens, DK and Wendt, RC, J. Appl. Polym. Sci. 1969, 13, 1741-1747.

[0094] Equation (3): γ = γa + γb

[0095] Resin manufacturing example 1 The alcohol component shown in Table 2, the carboxylic acid component other than trimellitic anhydride, PET (only resin H3), the esterification catalyst, and the esterification promoter were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and then the pressure was reduced to 8 kPa for 1 hour. Then, the mixture was cooled to 190°C, and trimellitic anhydride shown in Table 2 was added, and the mixture was held at 210°C for 30 minutes, and the reaction was carried out under reduced pressure of 8 kPa until the softening point shown in Table 2 was reached, to obtain polyester resins (resins H1, H3 to H5).

[0096] Resin manufacturing example 2 The alcohol component, terephthalic acid, and esterification catalyst shown in Table 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 170 ° C. in a mantle heater in a nitrogen atmosphere. Then, a mixture of raw material monomers of a styrene-based resin and a radical polymerization initiator was dropped over 1 hour, and the temperature was raised to 200 ° C. and held for 30 minutes. Then, an esterification promoter was added, the temperature was raised to 235 ° C., and it was confirmed that the reaction rate reached 95% or more, and the reaction was carried out at 8.0 kPa for 1 hour. Then, after cooling to 190 ° C., trimellitic anhydride shown in Table 2 was added, and the mixture was held at 210 ° C. for 30 minutes, and the reaction was carried out under a reduced pressure of 80 kPa until the softening point described in Table 2 was reached, to obtain a composite resin (resin H2).

[0097] [Table 2]

[0098] Resin manufacturing example 3 The alcohol component, terephthalic acid, esterification catalyst, and esterification promoter shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 235° C. in a nitrogen atmosphere in a mantle heater. Thereafter, when it was confirmed that the reaction rate had reached 95% at 235° C., the reaction was continued under a reduced pressure of 80 kPa until the softening point shown in Table 3 was reached, to obtain a polyester resin (resin L1).

[0099] Resin manufacturing example 4 The alcohol component, terephthalic acid, esterification catalyst, esterification promoter, and hydrocarbon wax "PARACOL 6490" (manufactured by Nippon Seiro Co., Ltd., acid value: 18 mgKOH / g, hydroxyl value: 97 mgKOH / g) shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater under a nitrogen atmosphere, and the flask was kept at 235°C for 8 hours, after which the pressure in the flask was reduced and kept at 8 kPa for 1 hour. Thereafter, the flask was cooled to 160°C and returned to atmospheric pressure, and then, while the flask was kept at 160°C, a mixture of the bireactive monomer, raw material monomer of the styrene resin, and radical polymerization initiator shown in Table 3 was dropped over 3 hours. The flask was then kept at 160°C for 30 minutes, and the temperature was raised to 200°C, and the pressure in the flask was further reduced and kept at 8 kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the mixture was cooled to 190°C. Fumaric acid, sebacic acid, trimellitic anhydride, and a radical polymerization inhibitor shown in Table 3 were added, and the temperature was raised to 210°C at 10°C / h. Then, the mixture was reacted at 4 kPa until the softening point shown in Table 3 was reached, to obtain a composite resin (resin L2).

[0100] Resin manufacturing example 5 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 160°C in a nitrogen atmosphere in a mantle heater. Then, a mixture of raw material monomers for styrene-based resins and a radical polymerization initiator shown in Table 3 was added dropwise over 1 hour, and the temperature was raised to 200°C and maintained for 30 minutes. Then, the esterification promoter shown in Table 3 was added, and the temperature was raised to 235°C, and the reaction was continued under a reduced pressure of 80 kPa until the softening point shown in Table 3 was reached, to obtain a composite resin (resin L3).

[0101] Resin manufacturing example 6 The alcohol component, carboxylic acid component, esterification catalyst, and esterification promoter shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere and maintained for 5 hours. After that, the mixture was maintained at 8 kPa for 1 hour, and then returned to atmospheric pressure and cooled to 160°C, and a mixture of the bireactive monomer, raw material monomer of the styrene-based resin, and radical polymerization initiator shown in Table 3 was dropped over 1 hour. After that, the mixture was maintained at 160°C for 30 minutes, and then heated to 200°C, and reacted at 8 kPa until the desired softening point was obtained, to obtain a composite resin (resin D1).

[0102] [Table 3]

[0103] Toner manufacturing example 1 100 parts by mass of the binder resin shown in Table 4, 0.5 parts by mass of a negatively charged charge control agent "Bontron E-304" (manufactured by Orient Chemical Industry Co., Ltd.), 2.0 parts by mass of a colorant "Cyanine Blue 4927" (manufactured by Cabot Corporation), 3.3 parts by mass of a release agent "Carnauba Wax-C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83°C), and 2.3 parts by mass of a release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 75°C) were thoroughly mixed in a Henschel mixer, and then melt-kneaded at a roll rotation speed of 200 r / min and a heating temperature inside the roll of 100°C using a co-rotating twin-screw extruder with a kneading section total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The resulting molten mixture was cooled, coarsely crushed, and then finely crushed using an I-2 type crusher (manufactured by Nippon Pneumatic Mfg. Co., Ltd.). The crushed mixture was classified to obtain a volume median particle size (D 50 ) yielded 6.5 μm toner particles. To 100 parts by mass of the obtained toner particles, 0.5 parts by mass of "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1.5 parts by mass of "Aerosil RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: silicone oil, average particle size: 40 nm) were added as external additives, and the mixture was mixed for 6 minutes at 3700 r / min using a Henschel mixer to perform external addition treatment, thereby obtaining a toner (toner A1).

[0104] Toner manufacturing example 2 100 parts by mass of the binder resin shown in Table 4, 0.5 parts by mass of a negatively charged charge control agent "Bontron E-304" (manufactured by Orient Chemical Industry Co., Ltd.), and 2.0 parts by mass of a colorant "Cyanine Blue 4927" (manufactured by Cabot Corporation) were thoroughly mixed in a Henschel mixer, and then melt-kneaded using a co-rotating twin-screw extruder with a kneading section total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm at a roll rotation speed of 200 r / min and a heating temperature inside the roll of 100°C. The resulting melt-kneaded product was cooled and coarsely pulverized, and then finely pulverized with an I-2 type pulverizer (manufactured by Nippon Pneumatic Co., Ltd.), classified, and the volume median particle size (D 50 ) yielded 6.5 μm toner particles. To 100 parts by mass of the obtained toner particles, 0.5 parts by mass of "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1.5 parts by mass of "Aerosil RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: silicone oil, average particle size: 40 nm) were added as external additives, and the mixture was mixed for 6 minutes at 3700 r / min using a Henschel mixer to perform external addition treatment, thereby obtaining toners (toners A2 to A4, A6).

[0105] [Table 4]

[0106] Toner Production Example 3 <Preparation of Resin Particle Dispersion> (1) Resins and solvents shown in Table 5 were placed in a 10-liter container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and dissolved at 73 ° C. for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the obtained solution so that the degree of neutralization was 50 mol% relative to the total amount of acid groups in the resin, and the solution was stirred for 30 minutes. Next, while maintaining the temperature at 73 ° C., 2380 g of deionized water was added over 1 hour while stirring at 200 r / min (circumferential speed 63 m / min), and phase inversion emulsification was performed. The obtained solution was continuously maintained at 73 ° C., and the solvent and a part of the water were distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, the aqueous dispersion was cooled to 30 ° C. while continuing stirring, and deionized water was added so that the solid content concentration was 35 mass%, thereby obtaining an aqueous dispersion of resin particles (resin particle dispersion X1).

[0107] (2) In a 10-liter container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen inlet tube, the resin and solvent shown in Table 5 were placed and dissolved at 73°C for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the obtained solution so that the degree of neutralization was 50 mol% relative to the total amount of acid groups in the resin, and the solution was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 1020 g of deionized water was added over 1 hour while stirring at 200 r / min (circumferential speed 63 m / min), and phase inversion emulsification was performed. While continuing to maintain the temperature at 73°C, the solvent and a part of the water were distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while continuing to stir, the aqueous dispersion was cooled to 30°C, and deionized water was added so that the solid content concentration was 35% by mass, thereby obtaining an aqueous dispersion of resin particles (resin particle dispersion Y1).

[0108] (3) 300g of resin D1 and a solvent were placed in a 2-liter container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen inlet tube, and dissolved at 40°C for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the obtained solution so that the degree of neutralization was 60 mol% relative to the acid value of resin D1, and the solution was stirred for 30 minutes. Next, while maintaining the temperature at 40°C, 600g of deionized water was added over 1 hour while stirring at 200r / min (circumferential speed 101m / min), and phase inversion emulsification was performed. The obtained solution was heated to 73°C, and the solvent and a part of the water were distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, the aqueous dispersion was cooled to 30°C while continuing stirring, and deionized water was added so that the solid content concentration was 35% by mass, thereby obtaining an aqueous dispersion of resin particles (resin particle dispersion Z1).

[0109] [Table 5]

[0110] <Preparation of release agent particle dispersion> (1) Into a 1-liter beaker, 120 g of deionized water, 86 g of resin particle dispersion Z1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiko Co., Ltd., melting point: 75°C) were added, and the mixture was melted and stirred while maintaining the temperature at 90 to 95°C to obtain a molten mixture. The obtained molten mixture was further dispersed for 40 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 90 to 95°C, and then cooled to room temperature (20°C). Deionized water was added to adjust the solid content to 20 mass%, and an aqueous dispersion of release agent particles (release agent particle dispersion W1) was obtained. The volume median particle diameter (D 50 ) was 470 nm.

[0111] (2) An aqueous dispersion of release agent particles (release agent particle dispersion W2) was obtained in the same manner as in the preparation of the release agent particle dispersion W1, except that 40 g of Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point: 93°C) was used instead of the paraffin wax "HNP-9."

[0112] <Preparation of Colorant Particle Dispersion> In a 1-liter beaker, 67.5 g of copper phthalocyanine pigment "ECB-301" (CI Pigment Blue 15:3, Dainichi Seika Chemicals Co., Ltd.), 189 g of anionic surfactant "Neopelex (registered trademark) G-15" (Kao Corporation, 15% by mass sodium dodecylbenzenesulfonate aqueous solution) and 100 g of deionized water were mixed and dispersed using a homogenizer at room temperature for 3 hours, and then deionized water was added so that the solids concentration became 25% by mass, thereby obtaining an aqueous dispersion of colorant particles (colorant particle dispersion C1). The volume median particle diameter (D 50 ) was 125 nm.

[0113] <Preparation of Toner Particles> In a 2-liter four-neck flask equipped with a dehydration tube, a stirrer, a thermometer, and a thermocouple, 200 g of resin particle dispersion X1 for cores, 150 g of deionized water, 16.8 g of release agent particle dispersion W1, 16.8 g of release agent particle dispersion W2, 40.6 g of colorant particle dispersion C1, and 7 g of nonionic surfactant "EMULGEN (registered trademark) 150" (Kao Corporation, 10 mass% aqueous solution of polyoxyethylene (average added mole number 50) lauryl ether) were placed and mixed at 25 ° C. Next, while stirring the mixture, an aqueous solution in which 24.1 g of ammonium sulfate was dissolved in 348 g of deionized water and 16 g of 4.8 mass% potassium hydroxide aqueous solution was added to adjust the pH to 8.4, and the aqueous solution was dropped at 25 ° C. for 30 minutes. Next, the obtained mixture was heated to 65 ° C. and kept at 65 ° C. to measure the volume median particle diameter (D 50 ) formed aggregate particles 1 of 5.3 μm.

[0114] Next, the temperature of the dispersion of aggregated particles 1 was lowered to 55° C., and while maintaining the temperature at 55° C., a mixture of 60 g of the resin particle dispersion Y1 for the shell and 31.4 g of deionized water was added dropwise over 120 minutes to obtain a volume median particle diameter (D 50 ) formed aggregated particles 2 having a size of 5.8 μm. To the resulting dispersion of aggregated particles 2, an aqueous solution prepared by diluting 13.5 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, effective concentration: 27% by mass) with 1,337 g of deionized water was added.

[0115] Next, the temperature was raised to 70°C over 1 hour, and after holding for 10 minutes, 30 g of 0.1 M sulfuric acid aqueous solution was added over 30 seconds. Thereafter, 30 g of 0.1 M sulfuric acid aqueous solution was added three times in the same manner every 10 minutes. After that, the mixture was held at 70°C for 10 minutes to obtain fused particles (core-shell particles) with fused surfaces. The pH at the end of the pre-fusion step was 4.0. Next, 20 g of a 4.8 mass% potassium hydroxide aqueous solution was added, the temperature was raised to 75°C over 20 minutes, and held for 1 hour, and the volume median particle size (D 50 The pH at the end of post-coalescence was 6.5.

[0116] Thereafter, it was cooled to 25° C., and the obtained dispersion of fused particles was subjected to suction filtration to separate the solid content, which was then washed with deionized water at 25° C. and vacuum dried at 35° C. for 48 hours to obtain toner particles a5. The physical properties of the obtained toner particles are shown in Table 6.

[0117] [Table 6]

[0118] 100 parts by mass of the obtained toner particles, 2.5 parts by mass of hydrophobic silica "Aerosil RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: silicone oil, average particle size: 40 nm), and 1.0 part by mass of hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Japan Co., Ltd., average particle size: 12 nm) were placed in a Henschel mixer, stirred, and passed through a 150 mesh sieve to obtain a toner with a core-shell structure (toner A5).

[0119] Examples 1 to 4, Comparative Examples 1 to 4, and Reference Example 1 Using a commercially available printer "OKI-712" (manufactured by OKI Data Corporation), a solid image measuring 20 mm wide and 50 mm long was printed in plain paper mode using each toner, without fixing, on the coated or uncoated paper shown in Table 7, leaving a margin of 20 mm from the top edge of the A4 size paper. Next, a thermostatic chamber set at 150°C was used to melt and dry for 5 minutes to fix the toner (solid image), and a print was obtained.

[0120] Details of the coated and uncoated papers used are as follows: <Coated paper> B1: OK Topcoat Matte (Oji Paper Co., Ltd., basis weight: 104.7 g / m 2 , paper thickness: approx. 82μm) B2: Economy mat (Kokuyo, grammage 86g / m 2 , paper thickness: 0.10mm) <Uncoated paper> B3: Excellent White (OKI, basis weight: 80g / m 2 )

[0121] The obtained print was rubbed 100 times back and forth with a load of 2N using a Gakushin RT300 Rub Fastness Tester (Fukuda Kikai Kogyo Co., Ltd.) with two layers of cloth (BEMCOT, Asahi Kasei Corporation) attached to the rubber. The image density on the cloth after rubbing was measured using a SpectroEye colorimeter (GretagMacbeth Co., Ltd.) and the image density (OD) was calculated by averaging the values ​​measured at three points to evaluate the rub resistance. The results are shown in Table 7. The lower the image density, the better the rub resistance.

[0122] [Table 7]

[0123] From the above, it is understood that, compared with Comparative Examples 1 to 3 in which the difference in surface tension between the coated paper and the toner is too large, and Comparative Example 4 in which the difference in surface tension is too small, printed matter with excellent abrasion resistance is obtained in Examples 1 to 4. Also, as shown in Reference Example 1, it is understood that in printing on uncoated paper, abrasion resistance is good even if the difference in surface tension with the toner is small. [Industrial Applicability]

[0124] The printed matter obtained by printing on coated paper by the method of the present invention is suitable for commercial printed matter such as high-end art books, photo books, magazine covers, posters, frontispieces, calendars, magazine texts, textbooks, flyers, and various catalogs.

Claims

1. A method for printing an image on coated paper using a toner, wherein the difference between the surface tension of the coated paper and the surface tension of the toner is 15.0 mN / m or more and 33.0 mN / m or less.

2. 2. The printing method according to claim 1, wherein the surface tension of the coated paper is 30.0 mN / m or more and 90.0 mN / m or less.

3. 2. The printing method according to claim 1, wherein the surface tension of the coated paper is 20.0 mN / m or more and 75.0 mN / m or less.

4. 2. The printing method according to claim 1, wherein the toner contains 60% by mass or more of a polyester resin.

5. The polyester resin of claim 1, wherein the polyester resin is a polyester resin having the formula (I): 【Chemical 1】 (wherein OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y are positive numbers each representing the average number of moles of alkylene oxide added, and the sum of x and y is 1 or more and 16 or less.) 5. The printing method according to claim 4, wherein the polycondensation product is an alcohol component containing 50 mol % or more of an alkylene oxide adduct of bisphenol A represented by the formula: and a carboxylic acid component containing an aromatic dicarboxylic compound.

6. A printed matter obtained by the method according to any one of claims 1 to 5.

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