JP2019203964A - Image forming method and toner for electrostatic charge image development used for the same - Google Patents

Abstract

To form a toner image with high adhesiveness to a recording medium, for example, a film that is soft and has a small thickness in image formation of an electrophotographic system.SOLUTION: In an image forming method of an electrophotographic system including a step of forming a toner image on a recording medium by using a toner for electrostatic charge image development, the recording medium is a film with a thickness of 70 μm or less, and the toner includes toner particles containing a phenolic resin.SELECTED DRAWING: None

Description

  The present invention relates to an image forming method and an electrostatic image developing toner used therefor.

  In the field of electrophotography, with the development of electrophotographic systems, development of toner for electrophotography corresponding to high image quality and high speed is required. As the binder resin contained in the toner, a styrene acrylic resin or a polyester resin excellent in low-temperature fixability is used, and in order to satisfy a plurality of performances simultaneously, a combination of a plurality of resins has been studied. In addition, with the diversification of printing media, the development of not only conventional paper but also so-called label printing and packaging material printing on the surface of a film or the like has begun.

  As a printing method for a film used for such applications, for example, printing is performed on a polypropylene film by electrophotography using an electrostatic image developing toner containing a binder resin composition containing a polyester resin and a polypropylene wax. A method has been proposed (for example, Patent Document 1).

JP, 2006-218448, A

  By the way, the printed matter of the soft packaging material, which is one of the packaging material applications, is stored in a roll state for a long time after printing, and is stretched and processed in the next step. Further, even after being processed into a packaging form, for example, in the case of bag-packaging, the toner image is applied with force in all directions as the shape of the package is deformed. There is a demand for image formation that does not cause image deterioration even in an image on a soft packaging material that is forced to undergo such extreme deformation.

  However, even if the toner as disclosed in Patent Document 1 is used, the adhesiveness with a soft packaging material (for example, a thin and soft film) which is one of the packaging materials described above is insufficient, and the flexible packaging material. It was not possible to sufficiently suppress the deterioration of the image above. Therefore, in order to prevent image degradation even on soft packaging materials that are subject to extreme deformation, the toner image layer can sufficiently follow the recording medium even when the printed matter is deformed. For this purpose, it is necessary to improve the adhesion between the toner image layer and the recording medium.

  The present invention has been made in view of the above circumstances. In electrophotographic image formation, for example, a toner image having high adhesiveness can be formed on a recording medium such as a thin and soft film. It is an object of the present invention to provide an image forming method that can be used.

  The above problem can be solved by the following configuration.

  The image forming method of the present invention is an electrophotographic image forming method including a step of forming a toner image fixed on a recording medium using an electrostatic charge image developing toner, wherein the recording medium has a thickness of 70 μm. The toner includes toner particles including a phenol resin as a binder resin.

  The electrostatic image developing toner of the present invention includes toner particles, and the toner particles include at least one amorphous resin selected from a vinyl resin and a polyester resin, and a phenol resin. Content is 5-30 mass parts with respect to the sum total of the said amorphous resin and the said phenol resin, and the sum total of the said amorphous resin and the said phenol resin is 70 mass% or more with respect to the said toner particle. It is.

  According to the present invention, in electrophotographic image formation, a toner image having high adhesion to a recording medium can be formed even on a recording medium such as a thin and soft film.

FIG. 1 is a diagram schematically illustrating a configuration example of an image forming apparatus used in the present embodiment. FIG. 2 is a diagram schematically illustrating a configuration example of an image forming apparatus for carrying out an image forming method using a recording medium accommodated in a roll shape according to another embodiment. FIG. 3 is a diagram for explaining the content of an image bending test in the embodiment.

  An image forming method according to an embodiment of the present invention is an electrophotographic image forming method including a step of forming a toner image fixed on a recording medium using an electrostatic charge image developing toner.

  As a result of intensive studies, the present inventors have obtained that, by adding a phenol resin as a binder resin to toner particles, high adhesiveness can be obtained, for example, for a film such as a soft packaging material. It has been found that image deterioration can be suppressed even when deformation is applied.

  The reason for this is not clear, but is presumed as follows. It is considered that the phenol resin has a phenol group in the main chain, so that the benzene ring of the phenol group is easily adhered to the surface of the film as a recording medium, and the adhesion between the toner image and the film is enhanced. In addition, an interaction (electrostatic attraction) is likely to occur between the benzene ring of one molecule of the phenol resin and the weakly positive (δ +) hydrogen of the phenol group of the other molecule. It is considered that the strength (toughness) of the steel tends to increase and the followability to deformation tends to increase. Thereby, it is considered that deterioration of the image can be suppressed even if the printed matter is deformed.

  In addition, by further including an amorphous resin having a benzene ring as a binder resin, the benzene ring of the amorphous resin and the hydrogen having a weak positive (δ +) of the phenol group of the phenol resin. However, since an interaction (electrostatic attractive force) occurs, it is considered that the strength (toughness) of the toner image is further increased and the followability to deformation is further increased. The present invention has been made based on these findings.

  First, an electrostatic image developing toner (hereinafter also simply referred to as “toner”) used in the image forming method and a developer using the toner will be described.

1. Toner The toner can be an aggregate of toner particles. The toner particles include toner base particles and external additives as necessary.

1-1. Toner Base Particles The toner base particles include a binder resin including at least a phenol resin, and may further include other components as necessary. Specifically, the toner base particles can have a continuous phase composed of a binder resin and a dispersed phase composed of other components.

(Binder resin)
The binder resin contains at least a phenol resin. The phenol resin can impart flexibility and good adhesion to the recording medium to the obtained toner image.

  The phenol resin may be a polymer obtained by addition condensation of phenols and aldehydes. Such a phenol resin may be a novolac resin obtained by reacting phenols and aldehydes in the presence of an acidic catalyst, or a resol obtained by reacting phenols and aldehydes in the presence of an alkaline catalyst. It may be a mold resin.

  Examples of phenols include phenol, cresol, xylenol, catechol, naphthol, alkylphenol, paraphenylphenol, bisphenols, and the like. Examples of aldehydes include formaldehyde, paraformaldehyde, hexamethylenetetramine, furfural and the like.

  The melting point of the phenol resin is preferably, for example, 65 to 100 ° C, and more preferably 70 to 90 ° C. The melting point of the phenol resin can be measured as the peak temperature of the endothermic peak when the temperature is raised at 10 ° C./min using, for example, a differential scanning calorimeter (DSC).

  The content of the phenol resin is preferably 5 to 30 parts by mass with respect to 100 parts by mass of the total of the binder resins (preferably the total of the phenol resin and the amorphous resin described later). When the content of the phenol resin is 5 parts by mass or more, the obtained toner image can be provided with good flexibility and good adhesion to the recording medium. Therefore, the obtained toner image can be applied to a recording medium such as a soft packaging material. Easy to improve adhesion. When the content of the phenol resin is 30 parts by mass or less, the content of the amorphous resin does not decrease too much, so that the heat melting property of the toner image layer is hardly impaired when the toner image is fixed on the recording medium. Further, the adhesiveness to the recording medium is not easily lost. The content of the phenol resin is more preferably 5 to 20 parts by mass, and preferably 10 to 15 parts by mass with respect to 100 parts by mass of the total of the binder resins (preferably the total of the phenol resin and the amorphous resin described later). More preferably, it is a part.

  The binder resin further includes an amorphous resin from the viewpoint of securing the adhesion of the fixed toner image to the recording medium and the strength (toughness) of the toner image itself, and securing the strength against mechanical stress as the toner. It is preferable. If it is weak against mechanical stress, problems such as toner breakage in the developing machine are likely to occur.

  The amorphous resin can be appropriately selected from amorphous resins used as binder resins for known toners. Examples of the amorphous resin include vinyl resin, amorphous polyester resin, polybutylene succinate, urethane resin, and urea resin. An amorphous resin may be used by 1 type and may use 2 or more types together. Among these, vinyl resin and amorphous polyester resin are preferable from the viewpoint of easily improving the adhesion to a recording medium such as a resin film.

  A vinyl resin is a polymer obtained by polymerizing a vinyl monomer. Examples of vinyl monomers include styrene monomers, (meth) acrylic monomers, olefins, halogenated olefin monomers, diolefin monomers, vinyl esters, vinyl ethers, vinyl ketones, N-vinyl compounds and other vinyl compounds are included. The vinyl monomer may be used alone or in combination of two or more.

  Examples of styrenic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-phenyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, p -Tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene and pn-dodecyl styrene.

  Examples of (meth) acrylic monomers include methacrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate. , 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, acrylic acid, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate , T-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, acrylonitrile, methacryloni Include Lil and acrylamide.

  Examples of olefins include ethylene, propylene, butene-1, pentene-1, and 4-methylpentene-1. Examples of the halogenated olefin-based monomer include vinyl chloride and vinylidene chloride. Examples of diolefinic monomers include butadiene, isoprene and chloroprene.

  Examples of vinyl esters include vinyl propionate, vinyl acetate, vinyl benzoate and vinyl formate. Examples of vinyl ethers include vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl phenyl ether and vinyl cyclohexyl ether. Examples of vinyl ketones include vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone. Examples of the N-vinyl compound include N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone. Examples of other vinyl compounds include vinyl naphthalene and vinyl pyridine.

  Examples of the vinyl resin include a copolymer of a styrene monomer and a (meth) acrylic acid monomer (styrene acrylic resin). The copolymerization ratio of the styrene monomer and the (meth) acrylic acid monomer is, for example, styrene monomer / (meth) acrylic acid monomer = 50/50 to 95/5 (mass ratio), Preferably, it can be set to 70/30 to 90/10 (mass ratio).

  Polyester resin (amorphous polyester resin) is a non-polymer of polymers obtained by polycondensation reaction of divalent or higher carboxylic acid (polyvalent carboxylic acid) and divalent or higher alcohol (polyhydric alcohol). It shows crystallinity.

  The polyvalent carboxylic acid is a compound having two or more carboxy groups in the molecule. Examples of polyvalent carboxylic acids include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid and other aliphatic dicarboxylic acids; cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; anhydrides of these carboxylic acids, alkyl esters having 1 to 3 carbon atoms, and the like. These polyvalent carboxylic acids may be used alone or in combination of two or more.

  The polyhydric alcohol is a compound having two or more hydroxy groups in the molecule. Examples of polyhydric alcohols include 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptane Saturated aliphatic diols such as diol, 1,8-octanediol, neopentyl glycol, 1,4-butenediol; unsaturated aliphatic diols such as fumaric acid; alicyclic diols such as 1,4-cyclohexanediol; Diols containing aromatic rings (aromatic diols) such as acids, isophthalic acid, bisphenol A propylene oxide adducts and the like are included. These polyhydric alcohols may be used alone or in combination of two or more.

  The amorphous polyester resin may be modified with a styrene acrylic resin. The amorphous polyester resin modified with styrene acrylic resin refers to a resin having a unit of amorphous polyester resin and a unit of styrene acrylic resin.

  Among these, from the viewpoint of increasing the strength (toughness) of the toner image, a vinyl resin or an amorphous polyester resin containing a monomer unit having a benzene ring is preferable, and the monomer unit having a benzene ring is not a main chain of the resin but a side chain. Particularly preferred are vinyl resins and amorphous polyester resins. A preferable example of such a resin is styrene acrylic resin.

  The weight average molecular weight (Mw) of the amorphous resin is preferably 16000 to 60000, and more preferably 25000 to 40000, from the viewpoint of easily obtaining the heat melting property of the toner image. The weight average molecular weight (Mw) of the amorphous resin can be measured by GPC (gel permeation chromatography).

  The glass transition point (Tg) of the amorphous resin is preferably 20 to 70 ° C. The glass transition point of the amorphous resin can be measured by, for example, a displacement point corresponding to the glass transition when the temperature is raised at 10 ° C./min using a differential scanning calorimeter (DSC).

  The content of the binder resin (preferably the total amount of phenol resin and amorphous resin) is preferably 60% by mass or more, more preferably 70% by mass or more, based on the toner base particles. More preferably, it is at least mass%.

(Other ingredients)
The toner base particles may further contain components other than the binder resin as long as the effects of the present embodiment can be obtained. Examples of other components include a colorant and a release agent.

  As the colorant, a known colorant can be used, and it may be a pigment or a dye. Examples of the colorant for black include carbon black and magnetic powder. Examples of carbon black include furnace black, channel black, acetylene black, thermal black and lamp black. Examples of magnetic powder include magnetite and ferrite.

  Examples of colorants for magenta or red include C.I. I. Pigment Red 2, 3, 5, 6, 7, 15, 15, 48: 1, 53: 1, 57: 1, 60, 63, 64, 68, the same 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 139, 144, 149, 150, 163, 166, 170, 177, 178, 184, 202, 206, 207, 209, 222, 238, and 269 are included.

  Examples of colorants for orange or yellow include C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 12, 14, 15, 17, 74, 83, 93, 94, 138, 155, 162, 180, and 185 are included.

  Examples of colorants for green or cyan include C.I. I. Pigment Blue 2, 3, 15, 15, 15: 2, 15: 3, 15: 4, 16, 17, 17, 60, 62, 66 and C.I. I. Pigment Green 7 is included.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 2, 6, 14, 15, 16, 19, 21, 21, 33, 44, 56, 61, 77, 79, 80, 81, 82, the same 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93 and 95 are included.

  The number average primary particle size of the colorant varies depending on the type, but is preferably about 10 to 200 nm. The colorant can be introduced into the toner base particles by, for example, adding the resin fine particles to the aggregation system at the stage of aggregating the resin fine particles by adding the aggregating agent. The colorant may be used after its surface is treated with a surface treatment agent such as a coupling agent.

  The content of the colorant is preferably 20% by mass or less, more preferably 1 to 10% by mass, and further preferably 3 to 7% by mass with respect to the toner base particles.

The toner base particles may be white toner, bright toner or transparent toner containing no pigment.
Examples of colorants for white include titanium oxide, heavy calcium carbonate, light calcium carbonate, titanium dioxide, aluminum hydroxide, titanium white, talc, calcium sulfate, barium sulfate, zinc oxide, magnesium oxide, magnesium carbonate, non- Inorganic pigments such as crystalline silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, smectite; organic pigments such as polystyrene resin particles and urea polymarin resin particles . Examples of white colorants include pigments having a hollow structure (for example, inorganic pigments such as hollow silica). Examples of bright colorants include metal powders such as aluminum, brass, bronze, nickel, stainless steel and zinc, mica coated with titanium oxide and yellow iron oxide, barium sulfate, layered silicate, and layered aluminum. Examples include coated flaky inorganic crystal substrates such as silicate, single crystal plate-like titanium oxide, basic carbonate, bismuth oxyoxychloride, natural guanine, flaky glass powder, and metal-deposited flaky glass powder.

  The release agent can be a wax. The wax can be appropriately selected from known compounds that can be used for the toner base particle material, and may be one kind or more. Examples of waxes include low molecular weight polyolefins such as polyethylene, polypropylene, polybutene, silicones that exhibit a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; carnauba Plant waxes such as wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; hydrocarbon waxes such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, stearyl stearate, behenic acid Behenyl, butyl stearate, propyl oleate, monostearic glyceride, distearic glyceride, pentaerythritol tetrabehenate, diethylene glycol monostearate , Dipropylene glycol distearate, distearate diglycerides, sorbitan monostearate, ester waxes such as cholesteryl stearate and the like are included.

  Among these, hydrocarbon waxes are preferable from the viewpoint of hardly hindering the adhesion between the recording medium (particularly the resin film) and the toner image.

  The melting point of the wax is usually 40 to 125 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. The melting point of the wax within the above range is preferable from the viewpoint of improving both the low-temperature fixability and the heat stability of the toner.

  The content of the wax is preferably 20% by mass or less, more preferably 1 to 10% by mass, and further preferably 3 to 7% by mass with respect to the toner base particles.

(Method for producing toner base particles)
The toner base particles can be produced by a known production method. For example, it can be produced by a kneading pulverization method or an emulsion aggregation method.

  The kneading and pulverizing method is a method in which a binder resin, a colorant and, if necessary, a release agent and an additive are mixed, kneaded with a kneader, and then pulverized. Furthermore, the toner base particles may be produced by performing a classification treatment as necessary.

  In the emulsion aggregation method, resin particles emulsified and dispersed in an aqueous medium, resin particles containing a release agent, and an aqueous dispersion of materials constituting the toner base particles, such as a colorant dispersion, are aggregated and united. It is a manufacturing method.

  In addition, an aqueous medium means the medium which consists of 50-100 mass% of water and 0-50 mass% of water-soluble organic solvents. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone and tetrahydrofuran. The organic solvent is preferably an alcohol-based organic solvent that does not dissolve the resulting resin.

  As a method for dispersing the material liquid in the aqueous medium, a known dispersion method such as a dispersion method using mechanical shearing force can be employed. Examples of the dispersing device used in such a dispersing method include a commercially available dispersing device “CLEARMIX” (manufactured by M Technique Co., Ltd., a registered trademark of the company) equipped with a rotor that rotates at high speed, an ultrasonic dispersing device, a machine Homogenizers, Manton Gorin, and pressure homogenizers are included.

  The material liquid usually contains a polymerization initiator and an organic solvent. Further, the material liquid may further include an additional component suitable for producing toner base particles. Examples of such further components include chain transfer agents, dispersion stabilizers and surfactants.

  As the polymerization initiator, a known oil-soluble or water-soluble polymerization initiator can be used. Examples of oil-soluble polymerization initiators include azo or diazo polymerization initiators and peroxide polymerization initiators.

  Examples of azo or diazo polymerization initiators include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane -1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile.

  Examples of peroxide-based polymerization initiators include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2 1,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine.

  Examples of water-soluble polymerization initiators include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

  The amount of the polymerization initiator in the material liquid is preferably 0.005 to 0.1 parts by mass, and 0.01 to 0.05 parts by mass with respect to 1 part by mass of the polymerizable monomer. Is more preferable.

  The organic solvent dissolves the polymerizable monomer and the polymerization initiator, but has low compatibility with the polymerization product, promotes phase separation of the polymerization product, and forms a film formed by polymerization of the polymerizable monomer. A component that does not hinder formation is preferred. Examples of the organic solvent include saturated hydrocarbons, aromatic hydrocarbons, and fatty acid esters having 8 to 18 carbon atoms, particularly 12 to 18 carbon atoms. Particular preference is given to toluene, ethyl acetate and hexadecane.

  Chain transfer agents are used for molecular weight adjustment in resin particles, examples include octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, n-octyl-3-mercaptopropionic acid ester, terpinolene, carbon tetrabromide and α-methylstyrene dimer is included.

  The dispersion stabilizer is used for polymerizing a polymerizable monomer dispersed in an aqueous medium or aggregating and fusing resin particles dispersed in an aqueous medium to produce toner base particles. This is preferable from the viewpoint of stably dispersing the particle material in the aqueous medium. Examples of the dispersion stabilizer include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate. , Barium sulfate, bentonite, silica, alumina and the like. Also included are polyvinyl alcohol, gelatin, methylcellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct and higher alcohol sodium sulfate. The dispersion stabilizer can be used even if it is a component generally regarded as a surfactant.

  The surfactant is preferable from the viewpoint of uniformly dispersing oil droplets of the material liquid containing the polymerizable monomer in the aqueous medium when polymerization is performed using the polymerizable monomer in the aqueous medium. Examples of the surfactant include ionic surfactants and nonionic surfactants.

  Examples of ionic surfactants include sulfonates, sulfates and fatty acid salts. Examples of such sulfonates include sodium dodecylbenzene sulfonate, sodium arylalkyl polyether sulfonate, sodium 3,3-disulfone diphenylurea-4,4-diazo-bis-amino-8-naphthol-6-sulfonate. Ortho-carboxybenzene-azo-dimethylaniline and sodium 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate.

  Examples of sulfate ester salts include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, and sodium octyl sulfate. Examples of fatty acid salts include sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, and polyoxyethylene (2) dodecyl ether sulfate sodium salt, Is included.

  Examples of nonionic surfactants include polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, higher fatty acid and polypropylene Esters with oxides and sorbitan esters are included.

  The toner base particles thus configured may be used as toner particles as they are, but from the viewpoint of improving fluidity, chargeability, cleaning properties, etc., toner base particles may be obtained by adding an external additive to the toner base particles. .

1-2. External Additive The external additive may be a known external additive. Examples of the external additive include inorganic fine particles, organic fine particles and a lubricant. By adding the external additive, the fluidity, chargeability, and cleaning properties of the toner particles are improved. An external additive may be used by 1 type and may use 2 or more types together.

  Examples of the inorganic fine particles include fine particles of silica, titanium oxide, alumina, and strontium titanate. The surface of the inorganic fine particles may be hydrophobized.

  Examples of silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., and commercially available products TS-720 manufactured by Cabot Corporation. , TS-530, TS-610, H-5, MS-5.

  Examples of the titanium oxide fine particles include commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B, MT-500BS, MT-600, and MT-600SS manufactured by Teika Co., Ltd. , JA-1, commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Industry Co., Ltd., and commercial products IT-S, IT- manufactured by Idemitsu Kosan Co., Ltd. OA, IT-OB, IT-OC are included.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  Examples of the organic fine particles include spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm, and specifically include homopolymers such as styrene and methyl methacrylate and fine particles of these copolymers. It is.

  Examples of lubricants include metal salts of higher fatty acids such as stearic acid, oleic acid, palmitic acid, linoleic acid, ricinoleic acid. Examples of the metal salt of stearic acid include zinc salt, aluminum salt, copper salt, magnesium salt and calcium salt of stearic acid. Examples of metal salts of oleic acid include zinc salts, manganese salts, iron salts, copper salts and magnesium salts of oleic acid. Examples of palmitic acid metal salts include zinc, copper, magnesium and calcium salts of palmitic acid. Examples of metal salts of linoleic acid include zinc and calcium salts of linoleic acid. Examples of metal salts of ricinoleic acid include zinc and calcium salts of ricinoleic acid.

  The external additive is preferably a particle having a number average primary particle size of 4 to 800 nm.

  The content of the external additive is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the toner base particles.

1-3. Structure / Physical Properties of Toner Particles The toner particles may have a single layer structure or a core-shell structure. Here, the core-shell structure means a structure having a core portion disposed on the inner side and a shell portion disposed on the surface of the core portion.

[Median diameter (D50v)]
The particle diameter of the toner particles is a median diameter (D50v) on a volume basis from the viewpoint of faithfully reproducing a very small dot image (for example, 1200 dpi (dpi; number of dots per inch (2.54 cm)) level). 3 to 8 μm is preferable.

  In general, the toner is required to faithfully reproduce the color of the photographic image. However, according to the toner including the toner particles having the particle diameter as described above, the dot image constituting the photographic image can be easily miniaturized. A high-definition photographic image equivalent to or higher than the printed image can be obtained. In particular, in a printing field called “on-demand printing” where a print order is received at a level of several hundred to several thousand copies, high-quality prints containing high-definition photographic images can be quickly delivered to the user.

  The volume-based median diameter (D50v) of toner particles can be measured and calculated using a device in which a computer system for data processing is connected to Multisizer 3 (manufactured by Beckman Coulter, Inc.).

  As a measurement procedure, 0.02 g of toner particles were mixed with 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner). Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. Pipet this toner dispersion into a beaker containing ISOTON II (manufactured by Beckman Coulter, ISOTON is a registered trademark of the company) in the sample stand with a pipette until the measured concentration reaches 5 to 10%. Set to 2500 and measure. The aperture diameter of “Multisizer 3” is 50 μm.

[Coefficient of variation (CV value)]
The coefficient of variation (CV value) in the volume-based particle size distribution of the toner particles is preferably 2 to 21%. The smaller the CV value, the sharper the particle size distribution, and the larger the toner particle size. That is, toner particles having a uniform size can be obtained, so that it is possible to reproduce a fine dot image and fine lines required for digital image formation with higher accuracy. In addition, when printing a photographic image, it is possible to create a high-quality photographic image of an image level made with printing ink or higher by using small-diameter toners of uniform size.

The coefficient of variation (CV value) in the volume-based particle size distribution represents the degree of dispersion in the particle size distribution of toner particles on a volume basis and is defined by the following equation. In the following formula, “σv” represents the standard deviation in the volume-based particle size distribution, and “D50v” represents the median diameter in the volume-based particle size distribution. The CV value can be adjusted by, for example, classification of toner particles.
CV value (%) = (σv / D50v) × 100

[Softening point]
The softening point (Tsp) of the toner particles is preferably 70 to 110 ° C., more preferably 70 to 100 ° C. In general, the colorant has a stable property that the spectrum does not change even under the influence of heat. However, by setting the softening point in the above range, the effect of heat applied to the toner particles during fixing on the colorant. Can be further reduced. Therefore, since image formation can be performed without imposing a burden on the colorant, it is expected that a wider and more stable color reproducibility is expressed. In addition, by setting the softening point of the toner particles in the above range, it is possible to fix the toner image at a low temperature, and it is possible to form an environment-friendly image with reduced power consumption.

The softening point of the toner particles can be controlled by, for example, the following methods alone or in combination.
(1) The type and composition ratio of monomers used for resin formation are adjusted.
(2) The molecular weight of the resin is adjusted according to the type and amount of chain transfer agent.
(3) Adjust the type and amount of wax.

  The softening point of the toner particles is, for example, using a flow tester CFT-500 (manufactured by Shimadzu Corporation), forming the toner particles into a cylindrical shape having a height of 10 mm, and heating the toner particles at a heating rate of 6 ° C./min. A pressure of 1.96 x 106 Pa is applied from the plunger and pushed out from a nozzle with a diameter of 1 mm and a length of 1 mm. This draws a curve (softening flow curve) between the plunger drop amount and temperature of the flow tester. It can be determined by setting the temperature at the amount of 5 mm as the softening point.

1-4. Method for Producing Toner Particles Toner particles can be prepared by adding the aforementioned external additive to toner base particles. Examples of the method of adding the external additive include a method of adding using a known mixing apparatus such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

  The obtained toner particles may be used as they are as a one-component developer (magnetic or non-magnetic one-component developer), or may be used as a two-component developer further containing carrier particles.

2. Developer The developer may be a one-component developer including the toner particles described above, or a two-component developer including the toner particles described above and carrier particles.

  As the carrier particles contained in the two-component developer, known particles that can be used as carrier particles of the two-component developer can be used. Examples of the carrier particles include magnetic particles, resin-coated magnetic particles whose surfaces are coated with a resin, and magnetic particle-dispersed resin particles in which magnetic particles are dispersed in the resin particles.

  Examples of the magnetic particle material include metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. Among these, the magnetic particles are preferably ferrite particles.

  The volume-based particle size of the carrier particles is preferably 15 to 100 μm, and more preferably 25 to 80 μm. The saturation magnetization value of the carrier particles is preferably 20 to 80 emu / g (2.0 × 10 −2 to 8.0 × 10 −2 A · m 2 / g). Carrier particles having such a particle size and saturation magnetization value are preferable from the viewpoint of forming a soft magnetic brush on the developing sleeve during image formation and forming a toner image having excellent sharpness. The volume average particle diameter and the saturation magnetization value can be measured by a known measuring device. Specifically, the volume reference particle size is measured by a laser diffraction particle size analyzer “HELOS” (manufactured by Sympatech) equipped with a wet disperser, and the saturation magnetization is “DC magnetization characteristic automatic recording device 3257-35” (horizontal It can be measured by Kawa Electric Co., Ltd.).

  The content of the toner particles with respect to the carrier particles is preferably 2 to 10% by mass.

  The two-component developer can be obtained by mixing toner particles and carrier particles by a known method. Moreover, the mixing apparatus used for mixing is not limited, and examples thereof include a Nauter mixer, a W cone, and a V-type mixer.

  Next, an image forming method using the above-described toner or developer will be described.

3. Image Forming Method The image forming method of the present embodiment is an electrophotographic image forming method, and includes a step of forming a toner image on a recording medium using the above-described toner.

Specifically, the step of forming the toner image may include the following steps 1) to 4).
1) A latent image forming step for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member 2) The electrostatic latent image formed on the surface of the electrophotographic photosensitive member is developed with a developer containing the above-described toner. Development process for forming a toner image 3) Transfer process for transferring the toner image formed on the surface of the electrophotographic photosensitive member to the surface of the recording medium 4) Heat fixing the toner image carried on the surface of the recording medium Fixing process

(recoding media)
The recording medium is a member for holding a toner image. As the recording medium, a known medium can be used. Examples thereof include plain paper from thin paper to thick paper, coated printing paper such as high-quality paper, art paper, and coated paper, commercially available Japanese paper and postcard paper. , OHP or packaging films, and fabrics. Especially, since it is suitable for label printing etc., a film is preferable and a resin film is more preferable.

  Examples of the resin constituting the resin film include polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polyethylene (PE), biaxially oriented polypropylene (OPP), unstretched polypropylene (CPP), and biaxially oriented. Nylon (ONY), unstretched nylon (CNY), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), high impact polystyrene (HIPS), and PLA (polylactic acid) Is included.

  In the image forming method according to the present embodiment, since the above-described toner is used, the toner image has good flexibility and good adhesion to a recording medium that is easily deformed, such as a soft packaging material. For this reason, the recording medium used in the image forming method according to the present embodiment is preferably a resin film that is easily deformed, has high affinity with the phenol resin contained in the toner, and has high adhesiveness. From the viewpoint of being easily produced, it is more preferable that the film is mainly composed of a resin containing an aromatic ring (for example, polyethylene terephthalate (PET), polystyrene (PS), impact-resistant polystyrene (HIPS)), and polyethylene terephthalate (PET). A film having a main component is particularly preferable. The “main component” means that the content with respect to the total mass of the film is 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more.

  The recording medium may be in the form of a sheet having a predetermined size, but is preferably in the form of being rolled up after the toner image is fixed. The winding after the image formation is suitable for carrying out efficient mass production of the packaging process, and the recording medium (film) after the image formation is stored in a roll form and used for the packaging process in the subsequent steps. It becomes possible. The recording medium may be either a surface-treated one or a surface-treated one. Examples of the surface treatment method include corona treatment and plasma treatment. In terms of cost, it is preferable that no surface treatment is performed, and in terms of image adhesiveness, it is preferable that surface treatment is performed.

  If the thickness of the recording medium is too thick, the suitability for processing as a soft packaging material may be insufficient. If the recording medium is too thin, the risk of breakage increases, so that the processing suitability as a soft packaging material may be insufficient. From the viewpoint of expressing sufficient processability as a flexible packaging material, the thickness of the recording medium is preferably 20 to 70 μm, and more preferably 30 to 55 μm.

  The image forming method can be performed using a known image forming apparatus. Hereinafter, further description will be given with reference to the drawings.

(Image forming device)
FIG. 1 is a diagram schematically illustrating a configuration example of an image forming apparatus 100 used in the present embodiment.

  The image forming apparatus 100 is a so-called tandem color image forming apparatus. As shown in FIG. 1, the image forming apparatus 100 includes a document image reading device SC for reading a document image, and four image forming units for forming a toner image. , A transfer device for transferring the toner image formed by the image forming unit to the recording medium P, a paper feeding / conveying device for conveying the recording medium P, and an unfixed toner image carried by the recording medium P And a heat roll type fixing device 50 as fixing means for fixing on the medium P.

  The document image reading device SC reads the image information of the document, converts it into YMCK color image data, and sends the corresponding color image data to the exposure device 3 described later.

  The four image forming units are apparatuses for forming four color images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Arranged in order. Each image forming unit includes a photoreceptor 1, a charging device 2, an exposure device 3, a developing device 4, a primary transfer roller 5, and a cleaning device 6.

  The photoreceptor 1 is, for example, a drum-shaped organic photoreceptor, and the charging device 2 is a non-contact charging device using, for example, corona discharge. The exposure device 3 is, for example, a laser oscillation device, and the developing device 4 is a developing device for a two-component developer that contains a two-component developer of any color of YMCK. The primary transfer roller 5 is, for example, a charging roller that is urged toward the photoreceptor 1 through the intermediate transfer belt 7, and the cleaning device 6 is made of, for example, a rubber that contacts the surface of the photoreceptor 1. A blade cleaning device having an elastic blade. The two-component developer is the toner of the present embodiment.

  The transfer device includes an endless intermediate transfer belt 7, a plurality of rollers 8 that stretch the intermediate transfer belt 7, a secondary transfer roller 9, and a cleaning device 10. The roller 8 includes one or more driving rollers, and may include a driven roller other than the driving roller. The secondary transfer roller 9 is, for example, a charging roller capable of forming a nip portion with the intermediate transfer belt 7 via the conveyed recording medium P, and the cleaning device 10 includes, for example, the intermediate transfer belt 7. A blade cleaning device having an elastic blade in contact with a surface.

  The paper feeding / conveying device conveys the recording medium P to the nip portion of the secondary transfer roller 9, the paper feeding cassette 11 for storing the recording medium P, the paper feeding roller 12 for taking out the recording medium P from the paper feeding cassette 11, A conveying roller 13 for controlling the position of the recording medium P being conveyed, a registration roller 14 for controlling the position of the recording medium P being conveyed, a discharge roller 15 for discharging the recording medium P discharged from the fixing device 50 to the outside of the apparatus, A paper discharge tray 16 for storing the recording medium P discharged outside the apparatus. The recording medium P is a resin sheet such as an OHP sheet.

  In the image forming apparatus 100 configured as described above, in the image forming unit, the surface of the photoconductor 1 that is rotationally driven is charged by applying a voltage from the charging device 2. The exposure device 3 irradiates the charged surface of the photosensitive member 1 with laser light corresponding to the image data of the corresponding color of YMCK to form an electrostatic latent image. The toner particles are supplied from the developing device 4 to the surface of the photoreceptor 1 on which the electrostatic latent image is formed, and the toner particles adhere to the portion of the electrostatic latent image to develop the electrostatic latent image.

  The toner images of the respective colors of YMCK carried on the surface of the photoreceptor 1 formed in the respective image forming units are applied on the rotating intermediate transfer belt 7 by applying a voltage from the primary transfer roller 5. A color toner image that has been transferred so as to overlap one another and is synthesized is formed on the intermediate transfer belt 7. The primary transfer roller 5 may be in contact with the photosensitive member 1 only at the time of primary transfer. For example, the primary transfer roller 5 in the image forming unit for black images is always in contact with the photosensitive member 1 and other The primary transfer roller 5 for color contacts the photoreceptor 1 only at the time of primary transfer.

  Deposits such as transfer residual toner on the surface of the photoreceptor 1 after the primary transfer are removed from the surface by the cleaning device 6.

  The recording medium P (for example, plain paper) accommodated in the paper feed cassette 11 is taken out from the paper feed cassette 11 by the paper feed roller 12 and is transported to the secondary transfer roller 9 through the transport roller 13 and the registration roller 14. . The color toner image on the intermediate transfer belt 7 is transferred onto the recording medium P by applying a voltage from the secondary transfer roller 9. For example, the secondary transfer roller 9 is urged toward the intermediate transfer belt 7 only at the time of secondary transfer.

  Deposits such as transfer residual toner on the surface of the intermediate transfer belt 7 after the secondary transfer are removed from the surface by the cleaning device 10.

  The color toner image on the recording medium P is fixed on the surface of the recording medium P by the heat and pressure of the fixing device 50. In this way, a fixed color toner image is formed on the recording medium P. The recording medium P on which the color toner image is formed is conveyed onto the paper discharge tray 16 via the discharge roller 15. By repeating the above steps, toner images fixed on the recording medium P are successively formed.

  FIG. 2 is a diagram schematically illustrating a configuration example of an image forming apparatus for performing an image forming method using the recording medium P accommodated in a roll shape.

  The image forming apparatus 200 includes a storage unit 201 that stores a roll-shaped recording medium P, a transport unit 202 that transports continuous sheets of the recording medium P to the upstream portion of the paper feed transport device, and a fixed toner image. The image forming apparatus 100 has the same configuration as the image forming apparatus 100 except that it further includes a transport unit 203 for transporting the formed recording medium P and a storage unit 204 for storing the recording medium P transported from the transport unit 203 in a roll shape. It has substantially the same configuration. The recording medium P is, for example, a series of PET sheets used for soft packaging materials.

  In the image forming apparatus 200 configured as described above, the recording medium P is continuously conveyed from the storage unit 201 to the secondary transfer roller 9 via the conveyance unit 202, and the toner image is fixed by the fixing device 50. A toner image is formed on the recording medium P in the same manner as the toner image is formed by the image forming apparatus 100 except that the recording medium P is stored in a roll shape in the storage unit 204 via the transport unit 203.

  Even in the formation of the toner image by the image forming apparatus 200, the toner image has sufficient flexibility and adhesiveness to the recording medium P. Therefore, even when the recording medium P is stored in a roll after the toner image is fixed, the toner image is prevented from being broken and peeled off. Further, when the recording medium P on which the toner image is formed is sent out from the roll during subsequent processing, peeling of the toner image is suppressed.

  As described above, in order to prevent image degradation even on soft packaging materials that are subject to extreme deformation, even if the printed matter is deformed, the toner image is resistant to deformation of the recording medium. It is preferable to follow sufficiently, and for that purpose, it is necessary to have good flexibility of the toner image and good adhesion to the recording medium.

  In the present embodiment, the toner particles constituting the toner contain a phenol resin as a binder resin. As a result, the obtained toner image has good flexibility and good adhesion to the recording medium, and therefore can have high adhesion to, for example, a soft packaging material regardless of the recording medium. As a result, even if the printed material is deformed, the toner image can sufficiently follow the recording medium to be deformed. For example, even if the printed material is used as a soft packaging material, the toner image is peeled off. Deterioration of an image to be performed can be suppressed.

1. Preparation of amorphous resin <Preparation of amorphous resin 1>
390 parts by mass of a 0.1 mol / L Na3PO4 aqueous solution was added to 1150 parts by mass of pure water, and the mixture was stirred at 10,000 rpm with CLEARMIX (manufactured by M Technique). To this, 58 parts by mass of a 1.0 mol / L CaCl 2 aqueous solution was gradually added to prepare a dispersion containing Ca 3 (PO 4) 2.

Next, the following compounds were mixed and dissolved to prepare a polymerizable monomer composition.
Styrene: 80 parts by mass n-butyl acrylate: 20 parts by mass Benzoyl peroxide: 2 parts by mass Then, the polymerizable monomer composition was added to the dispersion further stirred at 6,000 rpm with CLEARMIX. Then, the mixture was further stirred for 20 minutes to prepare a polymerizable monomer composition dispersion liquid in which droplets of the polymerizable monomer composition were dispersed.

The obtained polymerizable monomer composition dispersion is put into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introduction tube, and the temperature in the reaction vessel is raised to 60 ° C. while stirring under a nitrogen stream. For 5 hours. Furthermore, after raising the temperature in the reaction vessel to 80 ° C. and performing a polymerization treatment for 5 hours, the reaction vessel was cooled to room temperature. Hydrochloric acid was added to the produced resin to dissolve Ca3 (PO4) 2, and then washed with water, filtered, and dried to produce amorphous resin 1 (styrene acrylic resin).
The number average molecular weight (Mn) of the obtained amorphous resin 1 was 24,000, the weight average molecular weight (Mw) was 32,000, and the glass transition temperature was 59 ° C.

<Preparation of amorphous resin 2>
The following components were put into a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and heated to 170 ° C. to dissolve.
Bisphenol A propylene oxide 2-mole adduct: 245.0 parts by mass Terephthalic acid: 67 parts by mass Fumaric acid: 48 parts by mass 1.4-Cyclohexanediol (CHDO): 40 parts by mass As follows, 0.4 parts by mass of Ti (OBu) 4 was added, the temperature was raised to 235 ° C., and the reaction was performed for 5 hours under normal pressure (101.3 kPa) and further for 1 hour under reduced pressure (8 kPa). After cooling the obtained reaction liquid to 200 ° C., the reaction was performed under reduced pressure (20 kPa) until the softening point of the resin produced by the reaction reached the desired softening point. Next, the solvent was removed to obtain amorphous resin 2 (amorphous polyester resin).
The obtained amorphous resin 2 had a weight average molecular weight (Mw) of 19000 and a glass transition temperature Tg of 61 ° C.

<Preparation of amorphous resin 3>
Malic acid 0.4 mass part and germanium dioxide 1 mass part were dissolved in 100 mass parts 88 mass% lactic acid aqueous solution, and aqueous solution was obtained. 5.4 parts by mass of the obtained aqueous solution was added to 100 parts by mass of succinic acid and 89 parts by mass of 1,4-butanediol. After making the inside of a reaction system nitrogen atmosphere, it was made to react at 220 degreeC for 1 hour, and then it was pressure-reduced to 70 Pa over 1.5 hours, heating up to 230 degreeC. Then, it was made to react for further 2 hours, superposition | polymerization was advanced, and the amorphous resin 3 (polybutylene succinate resin, PBS) with a softening point of 125 degreeC was obtained.
The obtained amorphous resin 3 had a weight average molecular weight (Mw) of 160,000 and a glass transition temperature of 65 ° C.

2. 2. Preparation of toner particles 2-1. Preparation of toner base particles <Preparation of toner base particles 1>
The following components were mixed in the following composition ratio.
Amorphous resin 1 (amorphous resin): 980 parts by mass Novolak resin 1364A (manufactured by DIC Corporation, melting point 80-90 ° C.) (phenol resin): 20 parts by mass KET Blue (manufactured by DIC Corporation, copper phthalocyanine colorant) ) (Colorant): 50 parts by mass Bontron E-84 (Orient Chemical Co., Ltd., zinc salicylate complex) (charge control agent): 10 parts by mass Hydrocarbon wax (HNP-51, melting point 77 ° C., Nippon Seiwa ( Co., Ltd.) (release agent): 55 parts by mass The obtained mixture was weighed so that the amount of binder resin added (total amount of amorphous resin and phenol resin) was 1000 parts by mass, and the volume was 9 The mixture was put into a liter Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and the mixing speed was set at 2000 rpm for 5 minutes.

  The obtained mixture was melt-kneaded at 130 ° C. with an extrusion kneader PCM-30 (Ikegai Kako Co., Ltd.), and after cooling, a feather mill with a mesh opening of 2 mm (manufactured by Hosokawa Micron Co., Ltd.). ). The resulting coarsely pulverized product was finely pulverized with a mechanical pulverizer Kryptron KTM-0 type (manufactured by Kawasaki Heavy Industries, Ltd.) to an average particle size of 7 μm, and then an airflow classifier IDS-2 type (Japan) Coarse powder components were removed with Pneumatic Co., Ltd. Furthermore, the fine powder component was removed with a mechanical classifier 50ATP (manufactured by Hosokawa Micron Corporation). Thus, toner base particles 1 having a median diameter D50v: 6.8 μm were obtained.

<Preparation of toner base particles 2 to 7 and 17>
In preparation of toner base particles 1, toner base particles 2 to 7 and 17 were prepared by changing the blending amounts of the amorphous resin and the phenol resin as shown in Table 1.

Table 1 shows the resin compositions of the obtained toner base particles 1 to 7 and 17.

<Preparation of toner base particles 8 to 10 and 18>
In the preparation of toner base particles 2 to 4 and 17, toner base particles 8 to 10 and 18 were prepared by changing the amorphous resin 1 to the amorphous resin 2, respectively.

<Preparation of toner base particles 11-13>
In the preparation of the toner base particles 2 to 4, the hydrocarbon wax (HNP-51, manufactured by Nippon Seiwa Co., Ltd., melting point 77 ° C.) was changed to the ester wax (WEP-3, manufactured by NOF Corporation). Toner base particles 11 to 13 were prepared.

<Preparation of toner base particles 14 and 15>
In the preparation of toner base particles 3 and 9, novolak resin 1364A (manufactured by DIC Corporation) was changed to resole resin AH-5600 (manufactured by DIC Corporation, alkylphenol type, melting point 85 to 95 ° C.), and toner base particle 14 And 15 were prepared.

<Preparation of toner base particles 16>
In the preparation of the toner base particles 3, the amorphous resin 1 was changed to the amorphous resin 3 to prepare toner base particles 16.

<Adjustment of toner base particles 19>
In the preparation of the toner base particle 17, the hydrocarbon wax (HNP-51, manufactured by Nippon Seiwa Co., Ltd., melting point 77 ° C.) is changed to the ester wax (WEP-3, manufactured by NOF Corporation), and the toner base particles are used. 19 was prepared.

2-2. Preparation of toner particles <Preparation of toner particles 1>
To 100 parts by mass of toner base particles 1, 0.6 parts by mass of hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, hydrophobized) Degree = 63) 1.0 part by mass was added and mixed with a Henschel mixer (manufactured by Nihon Coke Kogyo Co., Ltd.) at a rotating blade peripheral speed of 35 mm / second at 32 ° C. for 20 minutes, and then a sieve with a 45 μm aperture was used. Coarse particles were removed. Thus, the external additive treatment was performed to prepare toner particles 1 (median diameter D50v: 6.8 μm, softening point: 115 ° C.).

<Preparation of toner particles 2 to 19>
Each of toner particles 2 to 19 was prepared in the same manner as toner base particle 1 except that toner base particles 2 to 19 were used instead of toner base particles 1 respectively.

  Table 2 shows the compositions of the obtained toner particles 1 to 19.

2-3. Preparation of developer <Preparation of developers 1 to 19>
Each of the toner particles 1 to 19 prepared above and a carrier particle having an average particle diameter of 35 μm coated with ferrite resin with an acrylic resin are mixed to develop a two-component developer having a toner particle concentration of 8% by mass. Agents 1 to 19 were prepared respectively.

3. Image formation and evaluation [Example 1]
As an image forming apparatus 200 as shown in FIG. 2, a color copying machine bizhub PRESS C71cf (manufactured by Konica Minolta Co., Ltd.) is used to prepare a developer 1 prepared as described above, and a toner adhesion amount is 8 g / m 2 on a recording medium. A solid image was formed. In addition, the image was formed at a fixing temperature of 185 ° C. and a system speed of 270 mm / sec. In this image forming apparatus, the recording medium is transported from the state wound in a roll shape, and after the toner image is formed, the recording medium is wound again in a roll shape. In this manner, an image was formed on a recording medium that was wound and installed in a roll shape and then wound and stored again after printing.
As a recording medium, a polyethylene terephthalate film (transparent, PET) having a thickness of 40 μm was used.

[Examples 2 to 16, Comparative Examples 1, 2 and 5]
An image was formed on a recording medium in the same manner as in Example 1 except that the type of developer was changed as shown in Table 3.

[Examples 17 to 21, Comparative Examples 3, 4 and 6]
An image was formed on the recording medium in the same manner as in Example 1 except that the type of recording medium and the type of developer were changed as shown in Table 3. In Table 3, PP: polypropylene film (thickness 40 μm), PET (corona treatment): the surface of the polyethylene terephthalate film (thickness 40 μm) used in Example 1 is subjected to corona treatment.

  The image resistance to bending of the images obtained in Examples 1 to 21 and Comparative Examples 1 to 6 was evaluated by the following method.

[Image resistance to bending]
As shown in FIG. 3, the image portion of the film (F) having a fixed image of the developer is bent up to 90 ° along the outer peripheral surface of a cylinder 40 having a diameter of 5 mm, and then straightened (up to 180 °). The above-mentioned image portion having been subjected to the bending and stretching movements 500 times, 750 times, 1000 times, 1250 times and 1500 times at a reciprocating speed of 2 reciprocations per second, (Nippon Paper Crecia Co., Ltd.) was applied and rubbed for 5 cm with a load of 5.0 kPa, and the presence or absence of image peeling in the image area was confirmed, and evaluated according to the following criteria.
1 is a practically problematic level, and 2 or more is a practically problematic level.
1: Image peeling occurs at 500 times 2: Image peeling does not occur at 500 times, but image peeling occurs at 750 times 3: Image peeling does not occur at 750 times, but at 1000 times Image peeling occurs 4: Image peeling does not occur at 1000 times, but image peeling occurs at 1250 times 5: Image peeling does not occur at 1250 times, but image peeling occurs at 1500 times 6 : No image peeling even after 1500 times

  Table 3 shows the evaluation results of Examples 1-21 and Comparative Examples 1-6.

  As shown in Table 3, in Examples 1 to 21 using developers 1 to 16, it can be seen that the formed images have high bending durability of at least 500 times.

  In contrast, in Comparative Examples 1 to 4 using the developer 17 or 18 and Comparative Examples 5 and 6 using the developer 19, the bending durability of the formed image is less than 500 times, which is insufficient. I understand that.

  According to the present invention, in an electrophotographic full-color image, a toner image having excellent bending durability can be formed on a flexible recording medium made of resin. Therefore, according to the present invention, further spread of image formation in the electrophotographic system is expected.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Exposure device 4 Developing device 5 Primary transfer roller 6, 10 Cleaning device 7 Intermediate transfer belt 8 Roller 9 Secondary transfer roller 11 Paper feed cassette 12 Paper feed roller 13 Transport roller 14 Registration roller 15 Discharge roller 16 Paper discharge tray 40 Cylinder 50 Fixing device 100, 200 Image forming device 201 Storage unit 202, 203 Conveyance unit 204 Storage unit F Film P Recording medium SC Document image reading device

Claims (8)

An electrophotographic image forming method including a step of forming a toner image fixed on a recording medium using an electrostatic image developing toner,
The recording medium is a film having a thickness of 70 μm or less,
The toner includes toner particles containing a phenol resin as a binder resin.
Image forming method. The content of the phenol resin is 5 to 30 parts by mass with respect to 100 parts by mass in total of the binder resin.
The image forming method according to claim 1. The binder resin contained in the toner particles includes at least one amorphous resin selected from vinyl resins and polyester resins.
The image forming method according to claim 1. The toner particles include a hydrocarbon wax as a release agent.
The image forming method according to claim 1. The recording medium is wound into a roll after the toner image is formed.
The image forming method according to claim 1. The film is a film mainly composed of polyethylene terephthalate.
The image forming method according to claim 1. The thickness of the film is 20 to 70 μm.
The image forming method according to claim 1. An electrostatic charge image developing toner containing toner particles,
The toner particles include at least one amorphous resin selected from a vinyl resin and a polyester resin, and a phenol resin.
The content of the phenol resin is 5 to 30 parts by mass with respect to the total of the amorphous resin and the phenol resin, and the total of the amorphous resin and the phenol resin is based on the toner particles. 70% by weight or more,
Toner for developing electrostatic images.

Images