JP2008015136A - Electrostatic charge image developing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner which is inhibited from deteriorating caused by a low printing ratio and long residence time of the toner in a developing machine. <P>SOLUTION: The electrostatic charge image developing toner is formed of: coloring particles containing a binding resin, a coloring agent and a releasing agent; and an external additive, and the electrostatic charge image developing toner is characterized in that the glass transition temperature of the electrostatic charge image developing toner is 20 to 40°C, and the toner contains: the coloring particles having an average circularity of 0.960 to 0.985; and organic particulates having a number average particle diameter of 50 to 200 nm, a crosslinking degree of ≥80% and a CV value of 2 to 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic charge developing toner.

  With the reduction in power consumption of copiers, development of electrostatic charge developing toner (hereinafter also simply referred to as “toner”) that can be fixed at a low temperature is underway. As a technical means for fixing at low temperature, the toner can be melted and fixed at a lower temperature by lowering the glass transition temperature (Tg) of the toner. However, reducing the thermophysical properties of the toner deteriorates the cohesiveness and storage stability, and may cause various side effects such as deterioration in fluidity and developability in the machine. When an attempt is made to hold inorganic fine particles on the toner surface, the inorganic fine particles are buried in the toner surface due to the difference in surface hardness, and the image stability deteriorates due to a change in the toner surface.

  On the other hand, it is essential to add an external additive in order for the toner to have a necessary function as a toner such as fluidity. As such an external additive, for example, small-diameter silica, titania and the like are used.

  Currently, full-color images are being developed, and accordingly, it is desired to support a wide variety of print patterns. For example, in an office, there is a higher image need for a small amount of color in a black character image than a photographic image using all colors. In such a case, a certain color consumes a large amount of toner at a high printing rate, whereas a color having a low printing rate causes the toner to be stirred for a long time in the developing machine while the toner is low in consumption. The surface is subjected to stress, and the developer is deteriorated by burying the external additive. In particular, in the toner having a low Tg, the external additive is easily buried due to the softness of the resin. As a result, the transfer rate of the toner is greatly lowered, and the image stability varies depending on the printing rate. .

Under such circumstances, the colored particles containing the binder resin and the colorant, the volume average particle size is 80 to 300 nm, the gel fraction corresponding to the degree of crosslinking of the resin is 60% by mass or more, and the standard deviation is D50 × 0. A toner containing 2 or less resin particles is known (for example, see Patent Document 1), but the improvement effect is not sufficient.
JP 2004-163612 A

  An object of the present invention is to provide a toner for developing an electrostatic charge that has a low printing rate and suppresses toner deterioration due to a long residence time in a developing machine.

  The above object of the present invention is achieved by the following constitution while ensuring low temperature fixability.

  1. In an electrostatic charge developing toner formed from colored particles containing a binder resin, a colorant, and a release agent, and an external additive, the electrostatic charge developing toner has a glass transition temperature of 20 to 40 ° C. and an average circular shape. Static particles comprising colored particles having a degree of 0.960 to 0.985, organic fine particles having a number average particle diameter of 50 to 200 nm, a crosslinking degree of 80% or more, and a CV value of 2 to 15. Toner for charge development.

  2. 2. The electrostatic charge developing toner according to 1 above, wherein the toner addition amount of the organic fine particles is 0.5 to 2.0 parts by mass.

  According to the present invention, it is possible to provide a toner for developing an electrostatic charge that satisfies low-temperature fixability, has a low printing rate, and has little toner deterioration even when the residence time in the developing machine is long.

  Hereinafter, the present invention will be described in detail.

  The inventor of the present invention has disclosed a toner for electrostatic charge development formed from colored particles containing a binder resin, a colorant, and a release agent, and an external additive, and the glass transition temperature of the toner for electrostatic charge development is 20 to 40 ° C. And colored particles having an average circularity of 0.960 to 0.985 and organic fine particles having a number average particle diameter of 50 to 200 nm, a crosslinking degree of 80% or more, and a CV value of 2 to 15. It has been found that the toner for electrostatic charge development characterized by the above can maintain high transfer performance without deteriorating the toner due to a long residence time in the developing machine, specifically, the cleaning performance is not lowered. It depends on you.

  If the glass transition temperature of the toner is 20 to 40 ° C., the heat generated by stirring in the developing machine and particularly under high temperature and high humidity, the situation exceeds the glass transition temperature, and the stress resistance decreases. When an attempt is made to hold inorganic particles on the toner surface as in the prior art, the inorganic particles are buried in the toner surface due to the difference in surface hardness, and the image stability deteriorates due to the change in the toner surface.

  Therefore, by selecting organic fine particles that have a small difference in surface hardness and have high adhesion to the toner because it is an insulator, changes in the surface of the toner can be reduced even with toner having a glass transition temperature of 20 to 40 ° C. Can be achieved.

  In order for the organic fine particles to stably exist on the toner surface, it is necessary to control the unevenness on the surface of the colored particles, and the average circularity is preferably 0.960 to 0.985. If the circularity is less than 0.960, the organic fine particles collect in the concave portions on the toner surface, and the adhesion force between the surface of the photoreceptor and the transfer member cannot be reduced. When the circularity exceeds 0.985, the toner transfer performance is high, but the cleaning of the photosensitive member and the transfer member is lowered, and toner slip occurs.

  The organic fine particles used in the toner of the present invention has a number average particle diameter of 50 to 200 nm, but 70 to 100 nm is a more preferable range. If it is less than 50 nm, it is buried in the toner surface, and it is difficult to maintain the transfer efficiency over a long period of time. On the other hand, if it exceeds 200 nm, it is difficult to hold on the toner surface. The degree of crosslinking is 80% or more, and more preferably 90% or more. Further, the CV value indicating the distribution of the organic fine particles is 2 to 15, and by making it within this range, the embedding suppression on the toner surface and the retention on the toner surface are improved, and the transfer efficiency can be satisfied. . Furthermore, the CV value is preferably 2-10.

  The amount of organic fine particles added depends on the resin particle size, but is generally 0.5 to 2.0 parts by mass. This is because by setting the content to 0.5 to 2.0 parts by mass, the transfer efficiency is maintained over a long period of time, and the retention performance on the toner surface is also improved, so that carrier contamination can be further suppressed.

(Organic fine particles)
In the toner of the present invention, organic fine particles having a number average particle diameter of 50 to 200 nm, a crosslinking degree of 80% or more, and a CV value of 2 to 15 are used as the external additive.

  Examples of the organic fine particles include a styrene polymer, an acrylic polymer, a styrene / acrylic copolymer, the above cross-linked resin, a benzoguanamine, a melamine resin, and the like, and a mixture thereof may be used. The polymerizable monomer (monomer) which is a constituent material of the polymer and resin will be described.

  Examples of the styrene monomer include styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, 2,5. -Dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, 2,4,5-trimethylstyrene, 2,4,6-trimethylstyrene, pn-butylstyrene, pt-butylstyrene, Examples include pn-hexyl styrene, pn-octyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, 3,4-dichloro styrene, among others. Styrene is preferably used. These styrene monomers may be used alone or in combination of two or more.

  Examples of the acrylic monomer include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and n-butyl (meth) acrylate, acrylic acid, methacrylic acid, acrylonitrile, and acrylamide. Of these, methyl methacrylate is preferably used. These acrylic monomers may be used alone or in combination of two or more.

  Examples of the crosslinkable monomer that increases the degree of crosslinking include divinylbenzene, divinyltoluene, ethylene glycol di (meth) acrylate, ethylene oxide di (meth) acrylate, tetraethylene oxide di (meth) acrylate, and 1,6-hexanediol di (meta). ) Acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolpropane tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate, etc. It is done. Monomers having two or more ethylenically unsaturated groups in these molecules may be used alone or in combination of two or more.

<Number average particle diameter of organic fine particles>
The number average particle size of the organic fine particles added externally to the colored particles is specifically measured by the following method.

  Take a 30,000 times photograph with a scanning electron microscope, and capture the photograph image with a scanner. In the image processing analyzer LUZEX AP (manufactured by Nireco), the external additive present on the toner surface of the photographic image is binarized, and the horizontal ferret diameter is calculated for 100 organic fine particles. The value is the number average particle diameter. When the number average primary particle diameter of the organic fine particles is small and exists as an aggregate on the toner surface, the particle diameter of the primary particles forming the aggregate is measured.

<CV value>
The CV value in the particle size distribution based on the number used in the present invention represents the degree of dispersion in the particle size distribution of the organic fine particles based on the number, and is defined by the following equation. The smaller the CV value, the sharper the particle size distribution.

CV value = (standard deviation in number particle size distribution) / (number average particle diameter) × 100
For the CV value in the particle size distribution based on the number of toner particles used in the present invention, the particle size data of the sample measured according to the following conditions is transferred to a computer via the I / O unit, and the particle size distribution analysis is performed in the computer. It is a value calculated by the program.

<Degree of crosslinking>
In the present invention, the degree of cross-linking is measured by the following method and is a value calculated by the following formula.

  About 0.3 g of the dried resin particles are weighed as a sample, put into 30 g of toluene, and stirred for 24 hours. After stirring, the mixture is centrifuged at 45000 G for 5 minutes using a centrifuge, and then the supernatant liquid from which the dissolved product in toluene is extracted is removed. Next, after the undissolved material in toluene is dried with a vacuum dryer, its mass is measured, and the degree of crosslinking (mass%) is calculated by the following equation.

  Degree of crosslinking (mass%) = (mass (g) /0.3 (g) of undissolved toluene) × 100.

(Toner physical properties and constituent materials)
<Glass transition temperature of toner>
The glass transition temperature of the toner of the present invention can be measured using a DSC-7 differential scanning calorimeter (manufactured by PerkinElmer) or a TAC7 / DX thermal analyzer controller (manufactured by PerkinElmer).

  As a measurement procedure, 4.5 to 5.0 mg of toner is precisely weighed to two decimal places, enclosed in an aluminum pan (KITNO.0219-0041), and set in a DSC-7 sample holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Analysis was performed based on the data in Heat.

  The glass transition temperature draws an extension of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rise of the first peak and the peak apex, and the intersection is taken as the glass transition point. Show.

<Average circularity of colored particles>
The colored particles in the present invention refer to toner base particles containing a binder resin, a colorant, and a release agent before the external additive is attached. The circularity of the colored particles is a value measured using “FPIA-2100” (manufactured by Sysmex). Specifically, after the toner is blended with an aqueous solution containing a surfactant and subjected to ultrasonic dispersion for 1 minute and dispersed, the number of detected HPFs in the measurement condition HPF (high magnification imaging) mode using “FPIA-2100”. Measurement is performed at an appropriate concentration of 3000 to 10,000. Within this range, reproducible identical measurement values can be obtained. The circularity defined by the following formula was measured.

Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)
The average circularity is a value calculated by adding the circularity of each particle and dividing by the total number of particles. In order not to pick up the data of the external additive detached from the toner, the circularity is measured by measuring particles having a number reference particle diameter of 2 μm or more.

<Binder resin>
When the toner particles constituting the toner of the present invention are produced by a pulverization method, a dissolution suspension method, or the like, a styrene resin, (meth) acrylic resin, styrene- (meta) is used as a binder resin constituting the toner. ) Known vinyl resins such as acrylic copolymer resins and olefin resins, polyester resins, polyamide resins, carbonate resins, polyethers, polyvinyl acetate resins, polysulfones, epoxy resins, polyurethane resins, urea resins, etc. These various resins can be used. These can be used alone or in combination of two or more.

  In addition, when the toner particles constituting the toner of the present invention are produced by a suspension polymerization method, a miniemulsion polymerization aggregation method, an emulsion polymerization aggregation method, or the like, a polymerizable single amount for obtaining each resin constituting the toner Examples of the body include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2 , 4-dimethylstyrene, pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, etc. Or styrene styrene derivative; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, ethyl methacrylate Methacrylic acid such as propyl, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate Ester derivatives; methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate Acrylate derivatives such as phenyl acrylate; olefins such as ethylene, propylene, isobutylene; vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, vinyl Vinyl halides such as vinylidene fluoride; vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone Vinyl ketones; N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl compounds such as vinyl naphthalene and vinyl pyridine; acrylic acid or methacrylic such as acrylonitrile, methacrylonitrile, acrylamide Examples thereof include vinyl monomers such as acid derivatives. These vinyl monomers can be used alone or in combination of two or more.

  Moreover, it is preferable to use combining what has an ionic dissociation group as a polymerizable monomer. The polymerizable monomer having an ionic dissociation group has, for example, a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group, and specifically includes acrylic acid, methacrylic acid, Maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl And methacrylate and 3-chloro-2-acid phosphooxypropyl methacrylate.

  Furthermore, as a polymerizable monomer, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol A binder resin having a crosslinked structure can also be obtained using polyfunctional vinyls such as diacrylate.

<Chain transfer agent>
In order to adjust the molecular weight of the resin, a commonly used chain transfer agent can be used. The chain transfer agent used is not particularly limited. For example, mercaptans such as octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan, mercaptopropionate such as n-octyl-3-mercaptopropionate, terpinolene, Carbon tetrabromide and α-methylstyrene dimer are used.

<Radical polymerization initiator>
The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates such as potassium persulfate and ammonium persulfate, azo compounds such as 4,4'-azobis-4-cyanovaleric acid and its salts, 2,2'-azobis (2-amidinopropane) salts, peroxides Compounds and the like.

  Furthermore, you may use the said radical polymerization initiator as a redox-type initiator combined with the reducing agent as needed. By using a redox initiator, the polymerization activity is increased, the polymerization temperature can be lowered, and the polymerization time can be shortened.

<Surfactant>
The surfactant that can be used when emulsion polymerization is performed using the radical polymerizable monomer is not particularly limited, but the following ionic surfactants are preferably used.

  Examples of ionic surfactants include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6 Sodium sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate, etc.), sulfuric acid Ester salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, stearic acid) Potassium, calcium oleate), and the like.

  Nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, 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, ester of higher fatty acid and polypropylene oxide, sorbitan ester Polymerization may be carried out in combination with the ionic surfactant described above as required.

  In the present invention, these are mainly used as an emulsifier at the time of emulsion polymerization, but may be used for other processes or purposes, for example, as a dispersing agent for associated particles.

<Colorant>
As the colorant used in the present invention, all known dyes and pigments can be used. Specifically, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium Yellow, yellow iron oxide, ocher, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, permanent yellow (NCG), Vulcan fast yellow (5G, R), tart Rajn Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brillia Tokarmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Torujin 5B Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red , Pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perinone orange, oil orange, Baltic Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bituminous Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, anthraquinone green, titanium oxide, ritbon and mixtures thereof can be used. As for content, 1-20 mass parts is preferable with respect to 100 mass parts of resin (binder resin).

<Release agent>
In the present invention, it is preferable that a release agent (hereinafter also referred to as wax) is contained in the toner in order to impart appropriate release properties to the toner and prevent the occurrence of offset. The mold release agent preferably has a melting point of 40 to 150 ° C, more preferably 50 to 110 ° C.

  By having a melting point within the above range, it has been confirmed that good fixability can be obtained and good offset resistance and durability can be obtained even when the fixing temperature is set to a low temperature.

  The melting point of the release agent can be determined by differential scanning calorimetry (DSC). That is, the melting peak value when a sample of several mg is ripened at a constant rate of temperature rise, for example, (10 ° C./min) is defined as the melting point.

  Examples of the release agent that can be used in the present invention include solid paraffin wax, micro wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, and fatty acid ester wax. Partially saponified fatty acid ester wax, silicon varnish, higher alcohol and carnauba wax are preferably used.

  In the present invention, ester compounds represented by the following general formula are particularly preferred.

R _1- (OCO-R ₂ ) _n
In formula, n is an integer of 1-4, Preferably it is 2-4, More preferably, it is 3-4, More preferably, it is 4. R ₁ and R ₂ each represents a hydrocarbon group that may have a substituent. R ₁ has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, and more preferably 2 to 5 carbon atoms. R ₂ has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 18 to 26 carbon atoms.

  In the present invention, the toner may be formed using a dispersion obtained by heating and stirring in an aqueous medium using a surfactant or a dispersant described later as a release agent. In this case, for example, it is possible to prepare a wax emulsion prepared by emulsifying a release agent, and add it together with the colorant dispersion when the resin particles are aggregated.

<Charge control agent>
The toner of the present invention may contain a charge control agent as necessary. As the charge control agent, all known ones can be used. For example, fluorine activators, salicylic acid metal salts, metal salts of salicylic acid derivatives, etc., specifically, nigrosine dye Bontron 03, quaternary ammonium salt Bontron P-51, azo metal complex salt Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E-84, phenolic condensate E-89 (above, Orient Chemical Industry) TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, manufactured by Hodogaya Chemical Co., Ltd.), copy charge PSY VP2038 of quaternary ammonium salt, copy blue PR of triphenylmethane derivative, class Copy charge of ammonium salt NEGVP2036, copy charge NX VP434 (Manufactured by Kist), LRA-901, LR-147 (manufactured by Nippon Carlit Co., Ltd.) which is a boron complex, and other high molecular compounds having a functional group such as a sulfonic acid group, a carboxyl group, and a quaternary ammonium salt. Among these, azo metal complex compounds are preferable, and for example, those disclosed in paragraphs 0009 to 0012 of JP-A-2002-351150 are preferably used.

  In the present invention, the amount of charge control agent used is determined uniquely by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is uniquely limited. Although it is not a thing, Preferably it is used in 0.1-2 mass parts with respect to 100 mass parts of binder resin. Preferably the range of 0.2-5 mass parts is good.

  In the present invention, a charge control agent is preferably contained in the vicinity of the toner surface. That is, by containing the toner in the vicinity of the toner surface, it is possible to effectively impart chargeability to the toner and to ensure that the toner has fluidity by containing the charge control agent so as not to be exposed on the toner surface.

  As a specific content method, for example, there is a method of controlling the amount of the charge control agent added to the resin particles constituting the toner. That is, a method in which a large amount of charge control agent is added to the resin particles constituting the vicinity of the toner surface and the resin particles are aggregated so that the toner surface is formed with resin particles to which no charge control agent is added, An example is a method in which resin particles containing a control agent are aggregated and then encapsulated with a resin component not containing a charge control agent on the surface of the aggregated particles.

  As a method of incorporating the resin particles into the resin particles, when the dispersion diameter is kneaded with the binder resin and the dispersion diameter is adjusted or released, it may be added to the aqueous phase side and incorporated into the toner during the aggregation process or drying process.

<Toner manufacturing method>
The toner production method is not particularly limited as long as a toner satisfying the claims can be obtained. For example, suspension polymerization method, emulsion polymerization aggregation method, miniemulsion polymerization aggregation method, dispersion polymerization method, dissolution suspension method, Examples thereof include a melting method and a kneading and pulverizing method. Among these, the emulsion polymerization aggregation method and the miniemulsion polymerization aggregation method are preferably used because the average circularity of the colored particles can be easily controlled.

  Below, an example of miniemulsion polymerization / emulsion polymerization and an aggregation method is demonstrated.

(1) Dissolution / dispersion step of dissolving or dispersing the release agent in the radical polymerizable monomer (2) Polymerization step for preparing a dispersion of resin particles A having a hydrophilic resin and a hydrophobic resin (3) ) Aggregation step of aggregating resin particles and colorant particles in an aqueous medium to obtain aggregated particles (4) The aggregated aggregated particles are fused and aged by thermal energy, and a hydrophilic resin is applied to the surface of the toner base. An agglomeration step in which a hydrophobic resin is oriented inside to produce a toner base having a core / shell structure, and resin particles B are added during the growth process of the resin particles A, and after agglomeration is continued, agglomeration step (5) (6) Cooling step for cooling the dispersion of the toner base (7) Solid-liquid separation of the toner base from the cooled dispersion of the toner base And the concerned (8) Drying step for drying the washed toner base (9) Step for adding an external additive to the dried toner base Hereinafter, each step will be described in detail. explain.

(Dissolution / dispersion process)
This step is a step of preparing a radical polymerizable monomer solution of the release agent by dissolving or dispersing the release agent in the radical polymerizable monomer.

(Polymerization process)
In a preferred example of this polymerization process, a radically polymerizable monomer solution in which a release agent is dissolved or dispersed in an aqueous medium containing a surfactant is added, and mechanical energy is applied to form droplets. Then, the polymerization reaction is advanced in the droplets by radicals from the water-soluble radical polymerization initiator. In addition, you may add the resin particle as a core particle in the said aqueous medium, and you may perform several steps of polymerization reaction.

  By this polymerization step, resin particles having a release agent, a hydrophilic resin, and a hydrophobic resin are obtained. Such resin particles may be colored particles or non-colored particles. The colored resin particles can be obtained by polymerizing a monomer composition containing a colorant. Further, when using resin particles that are not colored, in the fusing step described later, the dispersion of the colorant particles is added to the dispersion of the resin particles to fuse the resin particles and the colorant particles. Thus, the toner base can be obtained.

(Aggregation / fusion process)
A salting-out agent composed of an alkali metal salt or an alkaline earth metal salt is added as a flocculant having a critical aggregation concentration or more in water containing resin particles and, if necessary, colorant particles to form aggregated particles. . In the aggregating step, release agent particles, charge control agents, internal additive particles such as resin particles having different thermal characteristics, and the like can be aggregated together with the resin particles and the colorant particles.

Specifically, the aggregation of the resin particles A is started, and particle growth is advanced to a target particle size. For example, when a toner having a median particle diameter (D ₅₀ ) of 6 μm on a volume basis is produced, aggregation is advanced until the particle diameter of the aggregated particles A grows to 30 to 70% of the toner particle diameter. Add the dispersion. The resin particles B preferably have a Tg higher than that of the resin particles A, and the addition amount of the resin particles B is preferably 10 to 80% by mass with respect to the resin particles A.

  After the dispersion of resin particles B is added, aggregation is further advanced and the particles are grown to the final particle size. After completion of the aggregation, the resin particles B are taken into the aggregate of the resin particles A.

  In this step, when a hydrophilic resin and a hydrophobic resin are present in the resin particles A, the hydrophilic resin is oriented on the surface of the particles to form a toner base having a core-shell structure. It can be done.

(Aging process)
Aging means preparing the aggregated and fused toner to a proper circularity. Aging is preferably performed by thermal energy (heating).

(Cooling process)
This step is a step of cooling the toner base dispersion. As a cooling treatment condition, cooling is performed at a cooling rate of 1 to 20 ° C./min. The cooling treatment method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

(Solid-liquid separation and washing process)
In this solid-liquid separation / washing step, a solid-liquid separation process for solid-liquid separation of the toner base from the dispersion of the toner base cooled to a predetermined temperature in the above-described step, and a solid-liquid separated toner cake (in a wet state) A cleaning process is performed to remove deposits such as a surfactant and a salting-out agent from an aggregate obtained by agglomerating a toner base in a cake form. The filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.

(Drying process)
This step is a step of drying the washed toner cake to obtain a dried toner base. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like. The moisture content of the dried toner base is preferably 5% by mass or less, and more preferably 2% by mass or less. In addition, when the toner bases subjected to the drying treatment are aggregated with a weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(External treatment process)
This step is a step in which an external additive is mixed with the dried toner base as necessary to produce a toner. As an external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

<Developer>
The toner according to the present invention can be used as a one-component developer or a two-component developer.

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.

  Further, it can be mixed with a carrier and used as a two-component developer. As the carrier, conventionally known magnetic particles such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. Ferrite particles are particularly preferable. The particle diameter of the carrier is preferably 20 to 100 μm, and more preferably 25 to 80 μm.

  The particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The coating resin is not particularly limited. For example, an olefin resin, a styrene resin, a styrene-acrylic resin, a silicon resin, an ester resin, a fluorine-containing polymer resin, or the like is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to. Among these, a coat carrier coated with a styrene-acrylic resin is more preferable because it can prevent the external additive from being detached and can ensure durability.

(Image forming device)
The image forming apparatus is not particularly limited as long as it is a tandem full-color image forming apparatus.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.

Example 1
(Preparation of colored particles)
<< Preparation of colored particles 1 >>
(Production of resin particles A)
First stage polymerization Into a 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device, 8 g of sodium dodecyl sulfate was charged with 3 L of ion-exchanged water, and stirred while stirring at a rate of 230 rpm under a nitrogen stream. The temperature was raised to 80 ° C. After heating, 10 g of potassium persulfate dissolved in 200 g of ion-exchanged water was added, the liquid temperature was again 80 ° C., the following monomer mixture was added dropwise over 1 hour, and then heated at 80 ° C. for 2 hours. Polymerization was performed by stirring to prepare resin particles. This is referred to as “resin particles (1H)”.

Styrene 480g
n-Butyl acrylate 250g
Methacrylic acid 68.0g
n-Octanethiol 16.0g
Second stage polymerization A 5 L reaction vessel equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introducing device was charged with a solution prepared by dissolving 7 g of polyoxyethylene (2) sodium dodecyl ether sulfate in 800 ml of ion-exchanged water. After heating to ℃, 260 g of the resin particles (1H) and a solution prepared by dissolving the following monomer solution at 90 ℃ were added, and a mechanical disperser CLEARMIX (M Technique Co., Ltd.) having a circulation path was added. ) To prepare a dispersion containing emulsified particles (oil droplets).

223 g of styrene
142g of n-butyl acrylate
n-Octanethiol 1.5g
190g of polyethylene wax (melting point 70 ° C)
Next, an initiator solution prepared by dissolving 6 g of potassium persulfate in 200 ml of ion-exchanged water is added to this dispersion, and this system is heated and stirred at 82 ° C. for 1 hour to obtain resin particles. It was. This is referred to as “resin particles (1HM)”.

Third stage polymerization Further, a solution prepared by dissolving 11 g of potassium persulfate in 400 ml of ion-exchanged water was added, and under a temperature condition of 82 ° C.,
405 g of styrene
162 g of n-butyl acrylate
Methacrylic acid 33g
n-Octanethiol 8g
A monomer mixture consisting of was added dropwise over 1 hour. After completion of the dropping, polymerization was carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to obtain resin particles. This is designated as “resin particle A”.

  A part of the resin particles A were collected and measured after washing and drying, and Tg was 21 ° C.

(Production of resin particles B)
Into a 5 L reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction device, 2.3 g of sodium dodecyl sulfate was charged with 3 L of ion-exchanged water, and the internal temperature was adjusted while stirring at a stirring speed of 230 rpm under a nitrogen stream. The temperature was raised to 80 ° C. After heating, 10 g of potassium persulfate dissolved in 200 g of ion-exchanged water was added, the liquid temperature was again 80 ° C., the following monomer mixture was added dropwise over 1 hour, and then heated at 80 ° C. for 2 hours. Polymerization was performed by stirring to prepare resin particles. This is a dispersion of “resin particles B”.

Styrene 520g
210g of n-butyl acrylate
Methacrylic acid 68.0g
n-Octanethiol 16.0g
A part of the dispersion of resin particles B was collected, measured after washing and drying, and Tg was 48 ° C.

(Preparation of colorant dispersion 1)
90 g of sodium dodecyl sulfate was dissolved in 1600 ml of ion-exchanged water with stirring. While stirring this solution, C.I. I. A dispersion of colorant particles was prepared by gradually adding 420 g of Pigment Blue 15: 3 and then dispersing the mixture using a stirrer “CLEARMIX” (M Technique Co., Ltd.). This is designated as “colorant dispersion 1”. The particle diameter of the colorant particles in this colorant dispersion liquid 1 was 110 nm as measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

(Aggregation / fusion process)
In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device, 300 g of resin particles A in terms of solid content, 1400 g of ion-exchanged water, 120 g of “colorant dispersion 1”, polyoxy A solution prepared by dissolving 3 g of ethylene (2) sodium dodecyl ether sulfate in 120 ml of ion-exchanged water was added and the liquid temperature was adjusted to 30 ° C., and then the pH was adjusted to 10 by adding a 5 M aqueous sodium hydroxide solution. Next, an aqueous solution in which 35 g of magnesium chloride was dissolved in 35 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After holding for 3 minutes, the temperature was raised and the system was heated to 90 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 90 ° C. In this state, the particle size of the associated particles was measured with “Coulter Multisizer 3”, and when the median diameter on the volume basis became 3.1 μm, 260 g of the dispersion of resin particles B was added, and further the particle growth reaction Was continued.

  When the desired particle size is reached, an aqueous solution in which 150 g of sodium chloride is dissolved in 600 ml of ion-exchanged water is added to stop particle growth, and further, the mixture is heated and stirred at a liquid temperature of 98 ° C. as a fusion process, whereby FPIA Fusion between particles was allowed to proceed until the circularity was 0.985 as measured by -2100. Thereafter, the solution was cooled to 30 ° C., hydrochloric acid was added to adjust the pH to 4.0, and stirring was stopped.

(Washing / drying process)
The particles generated in the aggregation / fusion process were solid-liquid separated with a basket type centrifuge “MARK III model number 60 × 40” (manufactured by Matsumoto Kikai Co., Ltd.) to form a wet cake of toner base particles. The wet cake was washed with ion exchange water at 45 ° C. until the electric conductivity of the filtrate reached 5 μS / cm with the basket-type centrifuge, and then transferred to a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). Was dried until the content became 0.5% by mass to prepare colored particles 1. The glass transition point of the colored particles 1 was 22 ° C.

<< Preparation of colored particles 2 >>
In the preparation of the colored particles 1, the second monomer polymerization monomer mass of the resin particles A is 245 g, n-butyl acrylate is 120 g, the third polymerization monomer weight is 423 g of styrene, n-butyl. Colored particles 2 were prepared in the same manner except that the acrylate was changed to 144 g and the methacrylic acid was changed to 33 g, and the agglomeration and fusion steps were carried out so that the circularity was 0.972. The colored glass 2 had a glass transition point of 33 ° C.

<< Preparation of colored particles 3 >>
In the preparation of the colored particles 1, the resin monomer A has a second-stage polymerization monomer weight of 263 g of styrene and n-butyl acrylate of 102 g, a third-stage polymerization monomer weight of styrene 423 g, and n-butyl. Colored particles 3 were prepared in the same manner except that the acrylate was changed to 144 g and the methacrylic acid was changed to 33 g, and the agglomeration and fusion steps were carried out so that the circularity was 0.961. The glass transition point of the colored particles 3 was 40 ° C.

<< Preparation of colored particles 4 >>
In the preparation of the colored particles 1, the polymer monomer mass in the second stage polymerization of the resin particles A is changed to 274 g of styrene and 91 g of n-butyl acrylate, and the resin particles B are not added in the (aggregation / fusion process). The colored particles 4 were prepared in the same manner except that the circularity was 0.970 in the aggregation / fusion process. The glass transition point of the colored particles 4 was 46 ° C.

<< Preparation of colored particles 5 >>
In the preparation of the colored particles 3, the colored particles 5 were prepared in the same manner except that the circularity was 0.950 in the aggregation / fusion process.

<< Preparation of colored particles 6 >>
In the preparation of the colored particles 3, the colored particles 6 were prepared in the same manner except that the circularity was 0.992 in the aggregation / fusion process.

[Preparation of organic fine particles]
<< Preparation of organic fine particles A >>
828 g of ion-exchanged water was charged into a 2 L separable flask equipped with a stirrer, a dropping funnel, a nitrogen introduction tube and a reflux condenser, and the temperature was raised to 70 ° C. under a constant stirring condition in a nitrogen gas stream. After 30 minutes, 0.6 g of ammonium persulfate was added as a polymerization initiator. Next, emulsification obtained by emulsifying 54 g of ion-exchanged water, 36 g of tetramethylolpropane triacrylate having a water solubility (25 ° C.) of 1% by mass or less and 18 g of a 16% by mass aqueous solution of sodium dodecylbenzenesulfonate with a homogenizer After 108 g of the dispersion was added all at once, the temperature of the polymerization reaction system was maintained at 70 ° C., and the polymerization reaction was carried out for about 3 hours.

  Next, 126 g of ion-exchanged water, 69 g of trimethylolpropane triacrylate having a solubility (25 ° C.) in water of 1% by mass or less, 28 g of ethylene glycol dimethacrylate, and 15 g of a 16% by mass aqueous solution of sodium dodecylbenzenesulfonate were obtained using a homogenizer. 252 g of the emulsified dispersion obtained by emulsification was dropped from the dropping funnel at a dropping speed of 1 g / min. After about 4 hours, the dropping was finished, and the polymerization reaction was continued for another 2 hours to produce a crosslinked resin fine particle emulsion. When the average particle diameter of the crosslinked resin fine particles in the crosslinked resin fine particle emulsion obtained above was measured, the number average particle diameter of the crosslinked resin fine particles was 40 nm.

  Next, the crosslinked resin fine particle emulsion obtained above was freeze-dried using a freeze dryer to obtain a white powdery product composed of the crosslinked resin fine particles.

<< Preparation of organic fine particles B >>
In the preparation of the organic fine particles A, organic fine particles B were prepared in the same manner except that the 16% by mass aqueous solution of sodium dodecylbenzenesulfonate was changed to a 13% by mass aqueous solution.

<< Preparation of organic fine particles C >>
In the preparation of the organic fine particles A, a 16% by weight aqueous solution of sodium dodecylbenzenesulfonate in a 10% by weight aqueous solution, 69 g of trimethylolpropane triacrylate, 28 g of ethylene glycol dimethacrylate, 76 g of trimethylolpropane triacrylate, 8 g of ethylene glycol dimethacrylate The organic fine particles C were prepared in the same manner except for changing to.

<< Preparation of organic fine particles D >>
In the preparation of the organic fine particles A, a 16% by weight aqueous solution of sodium dodecylbenzenesulfonate was changed to an 8% by weight aqueous solution, 69 g of trimethylolpropane triacrylate and 28 g of ethylene glycol dimethacrylate were changed to 84 g of trimethylolpropane triacrylate. In the same manner, organic fine particles D were prepared.

<< Preparation of organic fine particles E >>
Add 300 g of deionized water and 7 g of hexadecyltrimethylammonium chloride into a 2 L separable flask equipped with a stirrer, a nitrogen inlet tube, a reflux condenser, and a dropping funnel. The temperature was raised to 75 ° C., and 1 g of 2,2-azobis (2- (2-imidazolin-2-yl) propane) 1 g in 100% neutralized aqueous solution of acetic acid was added dropwise over 10 minutes. After aging for 5 minutes, 10 g of methyl methacrylate was added dropwise over 5 minutes. After further aging for 5 minutes, 10 g of methyl methacrylate, 30 g of styrene, 25 g of n-butyl methacrylate, 5 g of glycidyl methacrylate, and 30 g of neopentyl glycol dimethacrylate were added to a solution obtained by mixing 20 g of hexadecyltrimethylammonium chloride and 270 g of deionized water. The pre-emulsion obtained by stirring was added dropwise over 40 minutes. After aging for 40 minutes, the mixture was cooled to obtain a crosslinked polymer particle emulsion. The emulsion particles were spray-dried at a drying temperature of 50 ° C. to obtain white organic fine particles E.

<< Preparation of organic fine particles F >>
The organic fine particles F were prepared in the same manner except that 20 g of hexadecyltrimethylammonium chloride in the preparation of the organic fine particles E was changed to 15 g.

<< Preparation of organic fine particles G >>
Organic fine particles G were prepared in the same manner except that 30 g of neopentyl glycol dimethacrylate in the preparation of organic fine particles E was changed to 15 g.

<< Preparation of organic fine particles H >>
Organic fine particles H were prepared in the same manner except that the 16% by mass aqueous solution of sodium dodecylbenzenesulfonate in the preparation of the organic fine particles A was changed to a 4% by mass aqueous solution.

  Table 2 shows the number average particle diameter, the degree of crosslinking, and the CV value for the organic fine particles A to H.

[Production of toner]
《External treatment process》
In the “colored particles 1 to 6” prepared above, 1% by mass of hydrophobic silica (number average particle size = 12 nm) as an external additive and 0.3% by mass of hydrophobic titania (number average particle size = 20 nm) Further, the organic fine particles shown in Table 2 were added in the amounts shown in Table 3, and mixed by a Henschel mixer to prepare “Toners 1 to 11” shown in Table 3.

[Cyan developer]
Next, a ferrite carrier having a volume average particle diameter of 50 μm coated with a silicone resin was mixed with each of the prepared toners to prepare “Developers 1 to 11” having a toner concentration of 6%.

[Evaluation]
For image evaluation, a commercially available multi-function machine “bizhub Pro C500” (manufactured by Konica Minolta Business Technologies, Inc.) adopting a print image electrophotographic method is used, and a pixel rate of 5% is applied to A4 quality fine paper (64 g / m ² ). 5000 images with a blue solid portion with a pixel rate of 0.5% were printed on the black character image of No. 1. For the black toner, the black toner of “bizhub Pro C500” was used as it was, and as the cyan toner, the above-prepared toner was sequentially replaced with an apparatus for evaluation.

<Transfer rate>
After printing the 1st sheet and the 5000th sheet, a solid image (20 mm × 50 mm) having a pixel density of 1.30 was formed, and the transfer rate was determined by the following formula and evaluated.

Transfer rate (%) = (mass of toner transferred onto transfer material / mass of toner developed on photoreceptor) × 100
If the transfer rate is 90% or more, the image density is sufficient and is acceptable.

<Toner slipping through photoconductor cleaning>
After 5000 copies are completed, 10 continuous copies are made on A4 paper, and determination is made based on whether or not toner slippage occurs in the solid white portion.

<Fog>
The fog density was measured by using a reflection densitometer “RD-918” manufactured by Macbeth Co., Ltd. for the blank paper that was not printed first, and the average value was defined as the blank paper density.

  Subsequently, the density of 20 places was measured in the same manner on the 5000th white background portion continuously printed, and the above-mentioned white paper density was determined as the fog density from this average value, and the anti-fogging property was evaluated according to the following criteria. .

A: Fog density is less than 0.003 B: Fog density is less than 0.003 to less than 0.006 B: Fog density is less than 0.006 to less than 0.010 X: Fog density is 0.010 or more It is.

<Low temperature fixability>
The surface temperature of the heating roller of the fixing device of the evaluation machine was changed so that the paper surface temperature was changed in increments of 10 ° C. within the range of 80 to 150 ° C., and the toner image was fixed at each changed temperature before printing 5000 sheets. A fixed image was created. In creating the print image, high-quality paper (64 g / m ² ) of A4 size was used.

The fixing strength of the printed image obtained by fixing is fixed using a method in accordance with the mending tape peeling method described in Chapter 9 Section 1.4 of “Basics and Applications of Electrophotographic Technology: Electrophotographic Society”. The rate was evaluated. Specifically, after a 2.54 cm square betacyan print image with a cyan toner adhesion amount of 0.6 mg / cm ² was created, before and after peeling with “Scotch Mending Tape” (manufactured by Sumitomo 3M). The image density was measured, and the residual ratio of the image density was determined as the fixing rate.

  The “transfer material (paper) surface temperature” at which the fixing rate is 95% or more is defined as the minimum fixing temperature. The surface temperature of the transfer material (paper) was measured with a non-contact thermometer. The image density was measured with a reflection densitometer “RD-918” (manufactured by Macbeth).

A: Fixing is possible at a minimum fixing temperature of less than 100.degree. C .: Fixing is possible at a minimum fixing temperature of 100.degree. C. or more and less than 130.degree. C .: Fixing is possible at a minimum fixing temperature of 130.degree.

  In Table 4, the toner of the present invention has no change in transfer rate, no fogging, no photoconductor cleaning, and low-temperature fixability is at an acceptable level. On the other hand, the comparative toner did not satisfy all of transfer rate, fog, photoconductor cleaning slip and low temperature fixability.

Claims (2)

In an electrostatic charge developing toner formed from colored particles containing a binder resin, a colorant, and a release agent, and an external additive, the electrostatic charge developing toner has a glass transition temperature of 20 to 40 ° C. and an average circular shape. Static particles comprising colored particles having a degree of 0.960 to 0.985, organic fine particles having a number average particle diameter of 50 to 200 nm, a crosslinking degree of 80% or more, and a CV value of 2 to 15. Toner for charge development. The toner for electrostatic charge development according to claim 1, wherein the toner addition amount of the organic fine particles is 0.5 to 2.0 parts by mass.