KR20000053037A - Polymer-base toner and process for the production thereof - Google Patents

Abstract

PURPOSE: A polymer-base toner is provided which has a low fixing temperature and uniformly melting ability, and is excellent in shelf stability(blocking resistance) and hard to cause fogging, deterioration of image density, etc., and a production process thereof CONSTITUTION: A polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles, which comprise a polyfunctional ester compound formed of a tri-functional or still higher polyfunctional polyhydric alcohol and a carboxylic acid, and a colorant, and shell which is formed of a polymer having a glass transition temperature higher than that of a polymer component making up the core particles and covers each of the core particles, a production process thereof, an image forming process comprising using the polymerized toner, and an image forming apparatus containing the polymerized toner.

Description

Polymerized toner and its manufacturing method {POLYMER-BASE TONER AND PROCESS FOR THE PRODUCTION THEREOF}

In the electrophotographic method or the electrostatic recording method, a developer which visualizes an electrostatic latent image includes a two-component developer consisting of a toner and carrier particles, and a one-component developer consisting substantially of toner and not using carrier particles. The one-component developer includes a magnetic one-component developer containing a magnetic component and a nonmagnetic one-component developer containing no magnetic component. In the nonmagnetic one-component developer, a fluidizing agent such as colloidal silica is often added independently to improve the fluidity of the toner. As the toner, generally, colored particles obtained by dispersing a colorant such as carbon black or other additives in a binder resin and granulating them are used.

Toner production methods are classified into pulverization methods and polymerization methods. In the pulverization method, toner is obtained by melt-mixing a synthetic resin, a colorant, and other additives as necessary, followed by pulverization, and then classifying to obtain particles having a desired particle size. In the intermediate process, a polymerizable monomer composition is prepared by uniformly dissolving or dispersing various additives such as a colorant, a polymerization initiator, a crosslinking agent, a charge control agent, and the like into a polymerizable monomer, and then using an agitator in an aqueous dispersion medium containing a dispersion stabilizer. And to form fine droplet particles of the polymerizable monomer composition, followed by heating and suspension polymerization to obtain a toner (polymerized toner) having a desired particle size.

All of the developers substantially develop the electrostatic latent image by the toner. In general, in an image forming apparatus such as an electrophotographic apparatus or an electrostatic lock apparatus, an electrostatic latent image is formed by performing image exposure on a uniformly charged photosensitive member, and a toner image (visible image) in which toner is adhered to the electrostatic latent image. Then, the toner image is transferred onto a transfer material such as a transfer paper, and the unfixed toner image is then fixed on the transfer material by various methods such as heating, pressurization, and solvent vapor. In the fixing step, in most cases, a toner image is transferred between a heating roll (fixing roll) and a pressure roll, and the toner is thermally pressed and fused onto the transfer material.

An image formed by an image forming apparatus such as an electrophotographic copying machine is required to improve its fineness every year. Conventionally, toners used in the image forming apparatus are mainstream toners obtained by the grinding method. According to the pulverization method, colored particles having a large particle size distribution are easy to be formed, and in order to obtain satisfactory developing characteristics, it is necessary to classify the pulverized product and adjust it to a somewhat narrow particle size distribution. However, the classification itself significantly reduces the yield of the toner because of its complexity and poor production rate. Therefore, recently, polymerized toners that are easy to enter and do not have to go through complicated manufacturing processes such as classification have been attracting attention. According to the suspension polymerization method, a polymerized toner having a desired particle size and particle size distribution can be obtained without pulverizing or classifying. However, the conventional polymerized toner has a problem in that it cannot sufficiently cope with recent demands for high speed, full color, and energy saving.

Background Art In recent years, in copying machines, printers, and the like of electrophotographic systems, there is a demand for high speed copying and printing as well as reduction of power consumption. In the electrophotographic method, a particularly energy consuming process is a fixing process after transferring a toner from a photosensitive member onto a transfer material such as a transfer machine. In the fixing step, a heating roll heated at a temperature of 150 ° C. or higher is usually used to heat-melt the toner on the electronic material, and electric power is used as the energy source. Lowering the heating roll temperature is required from the viewpoint of energy saving. In order to lower the heating roll temperature, it is necessary to be able to fix the toner at a lower temperature than before. In other words, it is necessary to lower the fixing temperature of the toner itself. When using a toner that can be fixed at a lower temperature than the related art, the heating roll temperature can be lowered, and if the heating roll temperature can be lowered by that amount, the fixing time can be shortened, so that the copying and printing can be speeded up.

In the design of the toner, the glass transition temperature of the binder resin constituting the toner may be lowered in order to meet demands from the image forming apparatus such as energy saving and high speed copying. However, when the toner is formed of a binder resin having a low glass transition temperature, the toners tend to block and form aggregates during storage, transportation, or toner box of the image forming apparatus.

In recent years, it has been required to make color copying and color printing clear by an electrophotographic method. For example, in full color copying, in the fixing step, only melt softening the toner and fusing it onto the transfer material is insufficient, and it is necessary to uniformly melt and mix the toners of each color to be mixed. In particular, since the use of color images is often used for OHP (overhead projector) sheets for presentations at various meetings, the toner images fixed on the sheets can penetrate the sheets and form a clear image on the screen. That is, what is excellent in OHP permeability is calculated | required. To satisfy the OHP light transmittance, the toner is required to melt uniformly on a transparent synthetic resin OHP sheet. To this end, it is necessary to design the melt viscosity near the fixing temperature of the toner to be lower than that of the conventional one. As a method of lowering the melt viscosity of the toner, there is a method of lowering the molecular weight of the binder resin or lowering the glass transition temperature as compared with the conventional binder resin for toner. However, even when any method is selected, the toner tends to cause blocking, resulting in a poor toner.

Conventionally, as a method of obtaining a polymerized toner having excellent fixability, for example, JP-A-3-136065 proposes a method of suspending polymerizing a polymerizable monomer containing a colorant and an antistatic agent in the presence of a macromonomer. Macromonomers are relatively long linear molecules with polymerizable functional groups at the molecular chain ends, such as unsaturated groups such as carbon-carbon double bonds. According to this method, since the macromonomer is incorporated as a monomer unit in the molecular chain of the product polymer, a large number of branches due to the long linear molecules of the macromonomer occur in the molecular chain. The resulting polymer becomes a polymer of apparent high molecular weight by entanglement of its branches, i.e. physical crosslinking, so that the offset resistance of the polymerized toner is improved. On the other hand, the physical crosslinking by the macromonomer component, unlike chemical crosslinking using a crosslinkable monomer such as divinylbenzene, is a loose crosslinking structure, so that the crosslinking structure is easily collapsed by heating. Therefore, this polymerized toner is easily melted at the time of fixing using a heating roll, and thus is excellent in fixability. However, this polymerized toner is not satisfactory about storage property because aggregation of toners is likely to occur during storage.

As described above, in the conventional method for lowering the fixing temperature of the toner and improving the uniform meltability, an inverse correlation relationship occurs that the fixing property of the toner obtained is improved but the storage property is lowered. As a method of resolving this inverse correlation, a so-called capsule type toner is proposed which solves the problem of preservation by coating a toner composed of a binder resin having a low glass transition temperature with a polymer having a high glass transition temperature and improving blocking resistance. have.

As a method for producing a capsule-type toner, for example, Japanese Patent Laid-Open No. 60-173552 uses a jet mill apparatus to form a coating layer made of a colorant or magnetic particles or a conductive agent and a binder resin on a spherical nucleus particle surface having a small particle size. A method of forming is suggested. As the nucleus particles, thermoplastic resin transparent resins such as acrylic acid ester resins and styrene resins are used. In this publication, it is reported that according to this method, a multi-layered toner having excellent fluidity and improved functionality can be obtained. However, in this method, the use of nucleus particles having a low glass transition temperature tends to cause the nucleus particles themselves to aggregate. In this method, the film thickness of the cohesive resin adhering to the nucleus particles tends to increase. Therefore, in this method, it is difficult to obtain a toner having improved fixability and uniform meltability while maintaining preservability.

JP-A-2-259657 discloses crosslinked toner particles prepared by suspension polymerization in a solution in which an encapsulating polymer, a charge control agent and a release agent are dissolved in an organic solvent, and then a poor solvent is added to the surface of the crosslinked toner particles. A method for producing an electrophotographic toner for forming a coating of an encapsulating polymer containing a charge control agent and a release agent has been proposed. Therefore, in this method, since the solubility of the encapsulated polymer is reduced by the dropping of the poor solvent to precipitate on the surface of the crosslinked toner particles, it is difficult to obtain the spherical particles. In this method, the capsule wall formed on the surface of the crosslinked toner particles is not uniform in thickness and becomes relatively thick. As a result, the effect of improving developability and fixability is not sufficient.

Japanese Laid-Open Patent Publication No. 57-45558 discloses the dispersion of nucleated particles formed by polymerization in 1 to 40% by weight of a latex aqueous solution by mixing and dispersing them, and then adding a water-soluble inorganic salt to the fine particles obtained by emulsion polymerization on the surface of the nucleus particles. The manufacturing method of the toner for electrostatic charge image development which forms the coating layer by this is proposed. However, this method has a drawback that the charging of the toner is largely dependent on the environmental characteristics of the charging characteristics of the toner under the influence of the surfactant and inorganic salts remaining on the microparticles, and particularly under high temperature and high humidity conditions.

Japanese Unexamined Patent Publication No. 61-118758 discloses suspension particles of a composition containing a vinyl monomer, a polymerization initiator, and a colorant to obtain a core particle, and in the presence of the core particle, having hydrophilicity equal to or higher than that of the resin contained in the core particle. A method for producing a toner is disclosed in which a vinyl monomer that imparts a polymer having a glass transition temperature higher than the glass transition temperature of this resin is polymerized to form an envelope. This publication describes that a release agent such as low molecular weight polyethylene, carnauba wax, silicone oil or the like may be added to the core particles to prevent a part of the molten toner from adhering to the fixing roll surface. However, in this method, since vinyl monomers for forming an envelope are adsorbed and grown on the core particles, the vinyl monomers absorbed to the inside of the core particles are often polymerized to exhibit a clear core-shell structure. Therefore, in this method, it is difficult to obtain a toner having sufficiently improved shelf life. In addition, in this method, in order to clarify the core-shell structure and to improve the storage property, the thickness of the shell must be increased.

Japanese Laid-Open Patent Publication No. 7-128908 discloses a method for producing a polymerized toner obtained by directly suspending a monomer composition containing a polymerizable monomer, a colorant, and a release agent in an aqueous catalyst, wherein the release agent is 100 parts by weight of the polymerizable monomer. A method for producing a toner is disclosed, which comprises 10 to 40 parts by weight of sugar and a step of removing the release agent on the surface of the toner after the completion of the polymerization process. In this method, when a polymer having a polar group is added to the monomer and polymerized, the polar polymer is collected in the particle surface layer, thereby forming a core-shell structure. Further, in order to remove the release agent on the surface of the toner, contamination due to adhesion of the release agent (wax) to the developing sleeve, the photosensitive drum, the transfer drum, and the like can be reduced. However, in this method, it is not easy to improve the toner retention, fixing temperature, and the like sufficiently, so that it is easy to cause blur, decrease in printing concentration, and the like.

Disclosure of the Invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a polymerized toner having a low fixing temperature and uniform meltability, having excellent storage resistance (blocking resistance), and furthermore being less likely to cause cloudiness, lowering of printing concentration and the like, and a method for producing the same.

It is also an object of the present invention to provide a polymerized toner capable of coping with high speed copying, printing, full color, and energy saving, and a method of manufacturing the same.

It is also an object of the present invention to provide a polymerized toner capable of forming a toner image exhibiting excellent permeability (OHP permeability) when printing and fixing on an OHP sheet, and a method of manufacturing the same.

Another object of the present invention is to provide an image forming method using a polymerized toner having such excellent properties, and an image forming apparatus containing the toner.

The present inventors have diligently studied to overcome the problems of the prior art, and as a result, core particles made of colored polymer particles containing a polyfunctional ester compound formed from trifunctional or higher polyhydric alcohols and carboxylic acids and colorants, the core particles A polymerized toner having a core-shell structure covered with a shell made of a polymer having a glass transition temperature higher than the glass transition temperature of the constituent polymer component was found.

This polymerized toner is polymerized by suspending a composition containing a polyfunctional ester compound, a colorant, and a polymerizable monomer capable of forming a polymer having a glass transition temperature of 80 ° C. or less, preferably in the presence of a macromonomer to produce colored polymer particles. After preparing the colored polymer particles as core particles, the polymerizable monomer capable of forming a polymer having a higher glass transition temperature than the polymer component constituting the core particles in the presence of the core particles is suspended and polymerized to coat the core particles. It can manufacture preferably by forming the shell which consists of a polymer layer to make.

The polymerized toner of the present invention can lower the fixing temperature by the core particles containing a polyfunctional ester compound and a polymer component having a low glass transition temperature, improve uniform meltability, speed up copying and printing, full color, and OHP permeability. It is possible to meet the requirements of the present invention, and further to form a high-quality image that is less likely to cause blur, decrease in printing concentration, and the like. On the other hand, since the polymerized toner of the present invention can coat the core particles with a thin shell, it exhibits good storage resistance (blocking resistance) and can sufficiently meet the requirements such as fixability and uniform meltability.

The present invention has been completed based on these findings.

Thus, according to this invention, the core particle which consists of colored polymer particle containing the polyfunctional ester compound formed from trifunctional or more than trifunctional polyhydric alcohol and carboxylic acid, and a coloring agent is higher than the glass transition temperature of the polymer component which comprises this core particle. A polymerized toner having a core-shell structure coated with a shell made of a polymer having a glass transition temperature is provided.

According to the present invention, (1) in an aqueous dispersion medium containing a dispersant, a polyfunctional ester compound, a colorant, and a polymer having a glass transition temperature of 80 ° C. or lower formed of a trifunctional or higher polyhydric alcohol and a carboxylic acid can be formed. Suspending polymerization of the polymerizable monomer composition containing the polymerizable monomer for core to prepare a core particle composed of colored polymer particles, and then (2) the glass transition temperature of the polymer component constituting the core particle in the presence of the core particle. There is provided a method for producing a polymerized toner having a core-shell structure, in which a polymerizable monomer for shell capable of forming a polymer having a higher glass transition temperature is suspended to form a shell composed of a polymer layer covering core particles.

According to the present invention, a toner is attached to a surface of a photoconductor on which an electrostatic latent image is formed to make a visible image, and the visible image is transferred to a transfer material, wherein the polymerized toner having the core-shell structure is used as a toner. There is provided an image forming method characterized by using.

According to the present invention, there is provided a photoreceptor, means for charging the photoreceptor surface, means for forming an electrostatic latent image on the photoreceptor surface, means for accommodating toner, means for supplying the toner and developing an electrostatic latent image on the photoreceptor surface to form a toner image, and An image forming apparatus comprising means for transferring this toner image from a photosensitive member surface to a transfer material, wherein the means for accommodating toner contains a polymerized toner of the core-shell structure. .

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymerized toner and a manufacturing method thereof, and more particularly, to a polymerized toner for developing an electrostatic latent image formed by an electrophotographic method, an electrostatic lock method, or the like, and a method of manufacturing the same. The present invention also relates to an image forming method using the polymerized toner and an image forming apparatus including the polymerized toner.

1 is a cross-sectional view showing an example of an image forming apparatus to which the polymerized toner of the present invention is applied.

Best Mode for Carrying Out the Invention

The polymerized toner of the present invention is a polymerized toner having a core-shell structure composed of core particles and a shell covering the core particles. The polymerized toner of the present invention can be obtained by polymerizing a polymerizable monomer for shell in the presence of core particles. The core particles contain, as essential components, a polyfunctional ester compound formed of a trifunctional or higher polyhydric alcohol and a carboxylic acid, and a colorant in the polymer component (binder resin). The glass transition temperature of the polymer component constituting the shell is higher than the glass transition temperature of the polymer component constituting the core particle.

Multifunctional Ester Compound

The polyfunctional ester compound used in the present invention is an ester formed of a trifunctional or higher polyhydric alcohol and a carboxylic acid.

As a trifunctional or more than trifunctional alcohol, For example, Aliphatic alcohol, such as glycerin, pentaerythritol, pentaglycerol; Alicyclic alcohols such as phloroglucitol, quelcitol, inositol and the like; Aromatic alcohols such as tris (hydroxymethyl) benzene and the like; Sugars such as D-erythroose, L-arabinose, D-mannose, D-galactose, D-fructose, L-rhamnose, saccharose, maltose, lactose and the like; Sugar alcohols such as erythritol, D-thritol, L-arabitol, adonitol, xylitol and the like; Etc. can be mentioned. Among these, pentaerythritol is preferable.

Carboxylic acids include, for example, acetic acid, butyric acid, capronic acid, enanthic acid, caprylic acid, pelagonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, stearic acid, margaric acid, arachidic acid, seric acid, Aliphatic carboxylic acids such as meric acid, erica acid, brassidic acid, sorbic acid, linoleic acid, linolenic acid, behenyl acid, tetrolic acid, xymenic acid and the like; Alicyclic carboxylic acids such as cyclohexanecarboxylic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, 3,4,5,6-tetrahydrophthalic acid and the like; Aromatic carboxylic acids such as benzoic acid, toluic acid, cuminic acid, phthalic acid, isophthalic acid, terephthalic acid, trimesic acid, trimellitic acid, hemmellitic acid and the like; Etc. can be mentioned. Among these, the number of carbon atoms is preferably 10 to 30, more preferably 13 to 25 carboxylic acids, and more preferably an aliphatic carboxylic acid having this carbon atom number. Of the aliphatic carboxylic acids, stearic acid and myristic acid are particularly preferred.

In the polyfunctional ester compound used for this invention, the carboxylic acid which reacts with 3 or more functional groups (OH group) of polyhydric alcohols, and respectively forms an ester bond may be the same, or may differ from each other. When the kind of carboxylic acid which reacts with a polyhydric alcohol differs, the difference of the maximum value and minimum value of carbon atom number between carboxylic acids mutually becomes like this. Preferably it is nine or less, More preferably, it is five or less.

As a polyfunctional ester compound, the following Chemical Formula 1

(However, R ¹ , R ² , R ³ and R ⁴ are each independently an alkyl group or a phenyl group, and the number of carbon atoms of the alkyl or phenyl group is preferably 10 to 30, more preferably 13 to 25.)

The compound represented by is preferable.

The Examples of the polyfunctional ester compound is pentaerythritol tetra stearate, in the equation (1) of, R ^1, R ^2, R ³ and R ⁴ both are CH ₃ (CH _{2) 16} group compound], pentaerythritol tetra myristate [in the formula ^{(1), R 1, R} 2, both R ³ and R ⁴ is CH ₃ (CH _{2) 12} group compound], and the like, glycerol triazol Larkin acid. It is preferable that the polyfunctional ester compound is easily dissolved in the polymerizable monomer for core.

The polyfunctional ester compound is usually 0.1 to 40 parts by weight, preferably 1 to 20 parts by weight, more preferably per 100 parts by weight of the polymer component constituting the core particle or the monomer (polymerizable monomer for core) forming the polymer component. Is used in the proportion of 3 to 15 parts by weight. Since the use ratio of the polyfunctional ester compound is within the above-mentioned range, a polymerized toner having low fixing temperature and uniform meltability, excellent preservation (blocking resistance), and hardly occurring cloudiness, low concentration of printing factor, etc. You can get it. When the use ratio of the polyfunctional ester compound is too small, the effect is small, and when too large, it becomes difficult to form the core particles and the preservation property is also lowered.

coloring agent

As the coloring agent used in the present invention, for example, salt pigments such as carbon black, titanium white, nigrosine base, aniline blue, calco oil blue, chrome yellow, ultramarine blue, orient oil red, phthalocyanine blue, malachite green oxalate and the like; Magnetic particles such as cobalt, nickel, iron trioxide, iron trioxide, manganese oxide, zinc oxide, nickel iron oxide, and the like; Etc. can be mentioned.

As a colorant for magnetic color toner, C.I. direct red 1, C.I. direct red 4, C.I. acid red 1, C.I. basic red 1, C.I. modern red 30, C.I. direct blue 1, C.I. Direct Blue 2, C.I. Acid Blue 9, C.I. Acid Blue 15, C.I.Basic Blue 3, C.I.Basic Blue 5, C.I.Modern Blue 7, C.I.Direct Green 6, C.I.Basic Green 4, C.I.Basic Green 6 and the like. Pigments for magnetic color toner include sulfur lead, cadmium yellow, mineral first yellow, navel yellow, nephthol yellow S, Hanzai yellow G, permanent yellow NCG, tatrazine lake, red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Eosin Lake, Brilliant Carmine 3B, Manganese Purple, First Violet B, Methyl Violet Lake, Royal Blue, Cobalt Blue, Alkali Blue Lake, Victoria Blue Lake, Phthalocyanine blue, first sky blue, indanthrene blue BC, chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G, and the like.

Magenta coloring dyes for full color toner include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 , 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68 , 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207 and 209; C.I. pigment violet 19; C.I. bat red 1, 2, 10, 13, 15, 23, 29 and 35; Etc. can be mentioned.

Magenta dyes for full color toners include C.I.Sulfent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109 and 121; C.I. disperse red 9; C.I. solvent violet 8, 13, 14, 21 and 27; C.I. Disperse Violet 1; Oil-soluble dyes such as these; C.I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39 and 40; C.I. basic violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27 and 28; Basic dyes, such as these, are mentioned.

Cyan-colored pigments for full color toners include C.I. Pigment Blue 2, 3, 15, 16 and 17; C.I. bat blue 6; C.I. acid blue 45; And copper phthalocyanine pigments in which 1 to 5 phthalimide methyl groups are substituted in the phthalocyanine skeleton; Etc. can be mentioned.

Yellow pigments for full color toner include CI pigment yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 83 And 138; C.I. bat yellows 1, 3 and 20; Etc. can be mentioned.

These dye pigments are usually used in an amount of 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the polymer component or core polymerizable monomer constituting the core particles. The magnetic particles are usually used in a proportion of 1 to 100 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight of the polymer component or core polymerizable monomer constituting the core particles.

Core particle

The core particle used for this invention contains a (co) polymer of vinyl-type monomers, such as polyester resin and a (meth) acrylic acid ester-styrene copolymer, as a polymer component (binder resin). As a polymer component of a core particle | grain, (meth) acrylic acid ester-styrene copolymer is preferable at the point which the formation of the particle | grains by superposition | polymerization and control of glass transition temperature are easy.

In the polymerized toner of the present invention, the volume average particle diameter (dv) of the core particles is usually 0.5 to 20 m, and preferably 1 to 10 m. If the core particles are too large, the resolution of the image is lowered. In addition, the volume average particle diameter (dv) / number average particle diameter (dp) is usually 1.7 or less, preferably 1.5 or less. If this ratio is too large, the image resolution tends to decrease.

The co-particles used in the present invention are not particularly limited to the production method, and may be any of emulsion polymerization, suspension polymerization, precipitation polymerization, and soap free polymerization, but a method of suspension polymerization of the polymerizable monomer for core is produced. The core particles are preferable because they contain the polyfunctional ester compound and the colorant uniformly and improve the fixability.

The polymerizable monomer for core used in the present invention is one capable of forming a polymer having a glass transition temperature of usually 80 ° C or lower, preferably 10 to 70 ° C, more preferably 15 to 60 ° C. The polymerizable monomer for core can be used 1 type or in combination of 2 or more types. If the glass transition temperature of the polymer made of the polymerizable monomer for core is too high, the fixing temperature is high, OHP permeability is lowered, and it is not suitable for speeding up copying and printing.

The glass transition temperature (Tg) of a polymer is a calculated value (referred to as Tg) calculated according to the kind and ratio of monomers used. When there is one type of monomer to be used, Tg of the homopolymer formed from this monomer is defined as Tg of the polymer in this invention. For example, since Tg of polystyrene is 100 degreeC, when styrene is used independently, this monomer forms a polymer whose Tg is 100 degreeC. When two or more types of monomers are used and the resulting polymer is a copolymer, the Tg of the copolymer is calculated according to the type and ratio of the monomers to be used. For example, when 78% by weight of styrene and 22% by weight of n-butyl acrylate are used as the monomer, the monomer having a Tg of 50 ° C. is obtained because the Tg of the styrene-n-butylacrylate copolymer produced at this monomer ratio is 50 ° C. To form.

In addition, the definition of "polymerizable monomer for cores capable of forming a polymer having a glass transition temperature of 80 ° C or lower" does not mean that each of the monomers must form a polymer having a Tg of 80 ° C or lower. When using one type of monomer, the Tg of the homopolymer formed from this monomer should be 80 degrees C or less. However, in the case of using a mixture of two or more kinds of monomers, the Tg of the copolymer formed from the mixture of these monomers may be 80 ° C. or lower, and the Tg of the polymer alone in the mixture of these monomers exceeds 80 ° C. You may contain it. For example, if the homopolymer of styrene has a Tg of 100 ° C, styrene is the core when a copolymer having a Tg of 80 ° C or less can be formed by mixing with a monomer forming a low Tg polymer such as n-butylacrylate. It can be used as a kind of polymerizable monomer.

In the present invention, a vinyl monomer is usually used as the polymerizable monomer for core. Tg of a polymer is prepared to a desired range by using each vinyl monomer individually or in combination of 2 or more types.

Vinyl monomers used in the present invention include, for example, styrene monomers such as styrene, vinyltoluene, α-methylstyrene and the like; Acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, meta Derivatives of acrylic acid or methacrylic acid such as 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide and the like; Ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and the like; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride and the like; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; Vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; Nitrogen-containing vinyl compounds such as 2-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone and the like; Etc. can be mentioned. These vinyl monomers may be used independently and may be used in combination of some monomer. Among these, styrene-based monomers or acrylic acid or methacrylic acid derivatives can be preferably used as the polymerizable monomer for core.

Among these, a combination of a styrene monomer and a (meth) acrylic acid derivative is preferably used as the polymerizable monomer for core. Particularly preferred specific examples include a combination of styrene and butyl acrylate (ie, n-butyl acrylate) and styrene and 2-ethylhexyl acrylate (ie, 2-ethylhexyl acrylate).

It is preferable to use an arbitrary crosslinkable monomer together with the polymerizable monomer for core which consists of vinylic monomers for the improvement of the storage property of a polymerized toner. As a crosslinkable monomer, For example, aromatic divinyl compounds, such as divinylbenzene, divinyl naphthalene, and these derivatives: diethylenic unsaturated carboxylic ester, such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate; Divinyl compounds such as N, N-divinyl aniline and divinyl ether; Compounds having three or more vinyl groups; Etc. can be mentioned.

These crosslinkable monomers can be used individually or in combination of 2 or more types, respectively. It is preferable to use a crosslinkable monomer in the ratio of 0.1-5 weight part normally, Preferably it is 0.3-2 weight part per 100 weight part of polymerizable monomers for cores.

In the present invention, it is preferable to copolymerize the macromonomer with the polymerizable monomer for core in order to improve the balance of the storage and fixing properties of the polymerized toner. In order to copolymerize a macromonomer, what is necessary is just to superpose | polymerize the polymerizable monomer composition containing a polyfunctional ester compound, a coloring agent, and the polymerizable monomer for cores in presence of a macromonomer, and synthesize | combine a colored polymer particle (core particle). In practice, a method of suspending and polymerizing a macromonomer in a polymerizable monomer composition is preferred.

Macromonomers are relatively long linear molecules having polymerizable functional groups (such as unsaturated groups such as carbon-carbon double bonds) at the ends of the molecular chain. As a macromonomer, what has a vinyl polymerizable functional group at the terminal of a molecular chain, the oligomer or polymer of the number average molecular weight is normally 1,000-30,000 is preferable. When the macromonomer having a small number average molecular weight is used, the surface portion of the polymerized toner tends to be soft and the storage property tends to be lowered. When the macromonomer with a large number average molecular weight is used, fluidity | liquidity of a macromonomer will worsen, and fixability and storage property will fall.

Although the vinyl polymerizable functional group which has the terminal of a macromonomer molecular chain is acryloyl group, a methacryloyl group, etc. are mentioned, A methacryloyl group is preferable from a viewpoint of easy copolymerization.

It is preferable that the macromonomer used for this invention has a glass transition temperature higher than the glass transition temperature of the polymer obtained by superposing | polymerizing the polymerizable monomer for cores. The high and low Tg between the polymer and macromonomer obtained by polymerizing the polymerizable monomer for core is relative. For example, when a polymerizable monomer for cores forms a polymer of Tg = 80 degreeC, what is necessary is just a macromonomer whose Tg exceeds 80 degreeC. When the monomer for core forms a polymer of Tg = 50 degreeC, a macromonomer may be Tg = 60 degreeC, for example. Tg of a macromonomer is a value measured with a measuring instrument, such as a conventional DSC.

Specific examples of the macromonomer used in the present invention include polymers obtained by polymerizing styrene, styrene derivatives, methacrylic acid esters, acrylate esters, nitrile acrylates, methacrylonitrile, or the like, or two or more kinds thereof; Macromonomers having a polysiloxane skeleton; And the like disclosed in the fourth to seventh aspects of Japanese Patent Laid-Open No. 3-203746.

Among these macromonomers, polymers obtained by polymerizing hydrophilic, in particular, methacrylic acid esters or acrylic acid esters alone or in combination thereof are preferred in the present invention.

The amount of the macromonomer used is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 1 part by weight per 100 parts by weight of the polymerizable monomer for core. If the amount of the macromonomer used is small, the shelf life is lowered. When the amount of the macromonomer increases, fixability tends to decrease.

In the present invention, the core particles are preferably obtained by suspension polymerization of a polymerizable monomer for a core, a macromonomer and, if necessary, a crosslinkable monomer.

Suspension polymerization is usually carried out in an aqueous dispersion medium containing a dispersant. Specifically, the polymerizable monomer for the core (vinyl monomer), the polyfunctional ester compound, the colorant, the macromonomer, the crosslinkable monomer selected as necessary, the radical polymerization initiator, and other additives are mixed and uniformly dispersed in a ball mill or the like. A mixed liquid (polymerizable monomer composition) is prepared, and then the mixed liquid is poured into an aqueous dispersion medium containing a dispersant, dispersed using a mixing device having a high shear force, and granulated into fine droplets. Suspension polymerization at temperature.

Dispersants preferably used in the present invention are colloids of poorly water-soluble metal compounds. Examples of the poorly water-soluble metal compound include sulfates such as barium sulfate and calcium sulfate; Carbonates such as barium carbonate, calcium carbonate, magnesium carbonate and the like; Phosphates such as calcium phosphate; Metal oxides such as aluminum oxide, titanium oxide and the like; Metal hydroxides such as aluminum hydroxide, magnesium hydroxide, ferric hydroxide and the like; Etc. can be mentioned. Among these, the clade of the poorly water-soluble metal hydroxide is preferable because the particle size distribution of the polymer particles can be narrowed and the image sharpness is improved.

The colloid of the poorly water-soluble metal hydroxide is not limited by the manufacturing method thereof, but the colloid of the poorly water-soluble metal hydroxide obtained by preparing the pH of the aqueous solution of the water-soluble polyvalent metal compound to 7 or higher, particularly in the aqueous phase of the water-soluble polyvalent metal compound and the alkali metal hydroxide. Preference is given to colloids of poorly water-soluble metal hydroxides produced by the reaction of. This colloid is used as an aqueous dispersion.

The colloid of the poorly water-soluble metal compound used in the present invention preferably has a particle size distribution D ₅₀ (50% cumulative value of the individual particle size distribution) of 0.5 μm or less and a D ₉₀ (90% cumulative value of the individual particle size distribution) of 1 μm or less. Do. When the particle size of the colloid is large, the stability of polymerization is degraded, and the storage property of the polymerized toner is lowered.

Dispersants are usually used in proportions of 0.1 to 20 parts by weight per 100 parts by weight of the core monomer. When the use ratio of the dispersant is too small, sufficient polymerization stability is difficult to be obtained, and polymerization aggregates are easily generated. On the contrary, when the use ratio of the dispersant is too high, the effect of polymerization stability is saturated and not economical, and the viscosity of the aqueous dispersion medium becomes too high, making it difficult to form small droplets of the mixed liquid.

In this invention, a water-soluble polymer can be used as a dispersing agent as needed. Examples of the water-soluble polymer include polyvinyl alcohol, methyl cellulose, gelatin, and the like. In the present invention, it is not necessary to use a surfactant, but may be used to stably perform the polymerization in a range in which the environmental dependency of the charging characteristics of the polymerization toner is not increased.

As a radical polymerization initiator, Persulfates, such as potassium persulfate and ammonium persulfate; 4,4-azobis (4-cyanovaleric acid), 2,2-azobis (2-amidinopropane) dihydrochloride, 2,2-azobis-2-methyl-N-1,1-bis ( Hydroxymethyl) -2-hydroxyethylpropioamide, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azo Azo compounds such as bis (1-cyclohexanecarbonitrile) and the like; Radical initiators such as methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, Oil-soluble radical initiators, such as peroxides, such as diisopropyl peroxy dicarbonate and di-t- butyl peroxy isophthalate, can be illustrated. Moreover, the redox initiator which combined these polymerization initiators and a reducing agent is mentioned.

Among these radical polymerization initiators, oil-soluble radical initiators are preferable, and oil-soluble radical initiators selected from organic peroxides having a half-life temperature of 60 to 80 ° C, preferably 65 to 80 ° C and having a molecular weight of 250 or less are particularly preferable. Among the oil-soluble radical initiators, t-butylperoxy-2-ethylhexanoate is particularly preferable in view of low odor upon printing and low environmental destruction by volatile components such as odor.

The amount of the polymerization initiator is usually 0.001 to 3% by weight based on the aqueous medium. If the amount of the polymerization initiator is less than 0.001% by weight, the polymerization rate is slow. If the amount of the polymerization initiator is more than 3% by weight, particles having a particle diameter of less than 1 µm are byproducts, which is not preferable.

In this invention, various additives, such as a molecular weight adjuvant, can be mixed and used with the polymerizable monomer for cores as needed.

As a molecular weight adjuvant, For example, mercaptans, such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan; Halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide; Etc. can be mentioned. A molecular weight adjuvant can be added before a polymerization start or during polymerization. The molecular weight aid is usually used in a ratio of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight per 100 parts by weight of the polymerizable monomer for core.

In the polymerized toner of the present invention, since the polyfunctional ester compound also functions as a release agent, it is not necessary to use other release agents, but, for example, low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight poly within the scope of not impairing the object of the present invention. Low molecular weight polyolefins such as butylene; Paraffin waxes; You may use mold release agents, such as these.

Lubricants such as oleic acid, stearic acid and the like for the purpose of uniform dispersion of the colorant into the core particles; Dispersion aids such as silane-based or titanium-based coupling agents; Etc. may be used. Such lubricants and dispersants are usually used in ratios of about 1/1000 to 1/1 based on the weight of the colorant.

The polymerization for obtaining the core particles is usually 80% or more, preferably 85% or more, and more preferably 90% or more. When the polymerization conversion rate is less than 80%, a large amount of unreacted core polymerizable monomer remains, so that even when the polymerizable monomer for shell is added and polymerized, the copolymer of the polymerizable monomer for shell and the polymerizable monomer for core is used for the core particle surface. Because of the coating, the Tg difference between the core particles and the shell becomes small and the storage property of the polymerized toner tends to be lowered.

Shell

In the present invention, the polymerized toner may be obtained by polymerizing a polymerizable monomer for shell in the presence of core particles.

The polymerizable monomer for shell used in the present invention is capable of forming a polymer having a glass transition temperature higher than the glass transition temperature of the polymer component constituting the core particles. The high and low Tg of the polymer obtained from the polymerizable monomer for shell and the polymer component constituting the core particles is relative.

As the polymerizable monomer for shell, for example, monomers forming a polymer having a glass transition temperature of more than 80 ° C. such as styrene and methyl methacrylate may be used alone or in combination of two or more thereof. When the glass transition temperature of the polymer component of the core particle is much lower than 80 ° C, the polymerizable monomer for shell may form a polymer of 80 ° C or lower. It is necessary to set so that the glass transition temperature of the polymer which consists of a polymerizable monomer for shells is higher than the glass transition temperature of the polymer component of a core particle at least. The glass transition temperature of the polymer obtained by the polymerizable monomer for shell is usually 50 to 120 ° C, preferably 60 to 115 ° C, more preferably 80 to 110 ° C in order to improve the storage stability of the polymerized toner. If the glass transition temperature of the polymer made of the polymerizable monomer for shell is too low, even if the glass transition temperature is higher than the glass transition temperature of the polymer component of the core particle, the storage stability of the polymerized toner may be lowered. In addition, the glass transition temperature of the polymer component of a core particle can be represented by the calculated Tg of the polymer formed with the polymerizable monomer for cores in most cases.

The difference in glass transition temperature between the polymer made of the polymerizable monomer for core and the polymer made of the polymerizable monomer for shell is usually 10 ° C or higher, preferably 20 ° C or higher, and more preferably 30 ° C or higher.

When the polymerizable monomer for shell is polymerized in the presence of the core particles, it is preferable to use droplets smaller than the number average particle diameter of the core particles in the aqueous dispersion medium. When the particle size of the droplets of the polymerizable monomer for shell increases, the preservation of the polymerized toner tends to decrease.

In order to make small amount of the polymerizable monomer for shell into a droplet, the mixture of the polymerizable monomer for shell and an aqueous dispersion medium is undispersed using an ultrasonic emulsifier etc., for example. It is preferable to add the aqueous dispersion obtained by such a method to the reaction system in which a core particle exists.

The polymerizable monomer for shell is not particularly limited by the solubility in water at 20 ° C., but monomers having high solubility in water, specifically monomers having a solubility in water at 20 ° C. of 0.1% by weight or more, can be rapidly applied to the surface of the core particle. Since it is easy to transfer, it is easy to obtain a polymerized toner having good storage properties.

On the other hand, when a monomer having a solubility in water at 20 ° C. of less than 0.1% by weight is used as the polymerizable monomer for shell, the transition to the surface of the core particles is slowed down. desirable. Even when a monomer having a solubility in water at 20 ° C. of less than 0.1% by weight is used, an organic solvent having a solubility in water at 20 ° C. of at least 5% by weight is added to the reaction system so that the polymerizable monomer for shell can be quickly transferred to the core particle surface. It is easy to obtain the polymer particle which is favorable in storage property.

Examples of the polymerizable monomer for shell having a solubility in water at 20 ° C. of less than 0.1% by weight include styrene, butyl acrylate, 2-ethylhexyl acrylate, ethylene, and propylene. As a monomer whose solubility in water of 20 degreeC is 0.1 weight% or more, (meth) acrylic acid ester, such as methyl methacrylate and methyl acrylate; Amides such as acrylamide, methacrylamide and the like; Vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; Nitrogen-containing vinyl compounds such as 4-vinylpyridine and the like; Vinyl acetate, acrolein, etc. are mentioned.

Organic solvents which are preferably used when a shell monomer having a solubility in water at 20 ° C. of less than 0.1 wt% are used include lower alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, and the like; Ketones such as acetone, methyl ethyl ketone and the like; Ethers such as cyclic ethers such as tetrahydrofuran, dioxane and the like, dimethyl ether and diethyl ether; Amides, such as dimethylformaldehyde, etc. are mentioned.

The organic solvent is added in a proportion of an amount such that the solubility of the polymerizable monomer for shell in the dispersion medium (the total amount of water and the organic solvent) is 0.1% by weight or more. The amount of the specific organic solvent added varies depending on the type of organic solvent or the type and amount of the polymerizable monomer for the shell, but is usually 0.1 to 50 parts by weight, preferably 0.1 to 40 parts by weight, more preferably 0.1 to 100 parts by weight of the aqueous dispersion medium. To 30 parts by weight. The order in which the organic solvent and the polymerizable monomer for shell are added to the reaction system is not particularly limited, but in order to facilitate the transition of the polymerizable monomer for the shell to the core particles and to easily obtain a polymerized toner having good shelf life, the organic solvent is added first, and It is preferable to add the polymerizable monomer for shell afterwards.

When using a monomer having a solubility in water at 20 ° C. of less than 0.1% by weight and a monomer having at least 0.1% by weight, first, a monomer having a solubility in water of 20 ° C. of 0.1% by weight or more is added to polymerize, and then an organic solvent is added. After that, it is preferable to add and polymerize a monomer having a solubility in water at 20 ° C. of less than 0.1 wt%. According to this addition method, in order to adjust the fixing temperature of a superposition | polymerization toner, Tg of the polymer obtained from the monomer superposed | polymerized in presence of a core particle, and addition amount of a monomer can be controlled suitably.

It is preferable to use the polymerizable monomer for shells mixed with a charge control agent. Including a charge control agent in the shell can improve the chargeability of the polymerized toner. As the charge control agent, a charge control agent of various wars or incidental wars may be used. Specific examples of the charge control agent include nigrosine NO 1 (manufactured by Orient Chemical Co., Ltd.), nigrosine EX (manufactured by Orient Chemical Company), spiron black TRH (manufactured by Hodogaya Chemical Company), T-77 (Hodogaga Chemical Company) Manufactured by Gakusha), Bontron S-34 (manufactured by Orient Chemical Industries, Ltd.), Bontron E-84 (manufactured by Orient Chemical Industries, Ltd.), and the like. The charge control agent is usually used in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the polymerizable monomer for core.

As a specific method of polymerizing the polymerizable monomer for shell in the presence of the core particles, a method of continuously polymerizing by adding the polymerizable monomer for shell to the reaction system of the polymerization reaction carried out to obtain the core particles, or adding the core particles obtained from another reaction system And the method of superposing | polymerizing in steps by adding the polymerizable monomer for shell to this, etc. are mentioned.

The polymerizable monomer for the shell may be added in a batch in the reaction system, or continuously or continuously using a pump such as a flanger pump.

It is preferable to add a water-soluble radical initiator when adding the polymerizable monomer for shell, in order to obtain a core-shell polymer particle easily. This is because when the polymerizable monomer for shell is added, the water-soluble radical initiator is added to the water-soluble radical initiator in the vicinity of the outer surface of the core particle to which the polymerizable monomer for the shell is transferred, so that a polymer layer (shell) is easily formed on the surface of the core particle. .

As a water-soluble radical initiator, Persulfates, such as potassium persulfate and ammonium persulfate; 4,4-azobis (4-cyanovaleric acid), 2,2-azobis (2-amidinopropane) dihydrochloride, 2,2-azobis-2-methyl-N-1,1-bis ( Azo initiators, such as hydroxymethyl) -2-hydroxyethyl propioamide; Combinations of oil-soluble initiators such as kemenperoxide and the redox catalyst; Etc. can be mentioned. The amount of the water-soluble radical initiator is usually 0.001 to 1% by weight based on the aqueous catalyst.

Polymerized Toner

In the polymerized toner of the present invention, the weight ratio of the polymerizable monomer for core and the polymerizable monomer for shell is usually 40/60 to 99.9 / 0.1, preferably 60/40 to 99.5 / 0.5, more preferably 80/20 to 99 / 1 If the proportion of the polymerizable monomer for shell is too small, the effect of improving the storage properties is small. On the contrary, if the ratio is too large, the effect of reducing the fixing temperature and improving the OHP permeability is small.

The polymerized toner of the present invention has a volume average particle diameter of usually 2 to 20 µm, preferably 3 to 15 µm, and a particle size distribution (volume average particle diameter / number average particle diameter) of usually 1.6 or less, preferably 1.5 or less. Sharp spherical fine particles.

The polymerized toner of the present invention is a core-shell polymer polymer particle composed of a core particle and a shell covering the core particle. In the polymerized toner of the core-shell structure of the present invention, the average thickness of the shell is usually 0.001 to 1 m, preferably 0.005 to 0.5 m. The larger the thickness of the shell, the lower the fixability, and the smaller the shell, the lower the shelf life. The particle diameter of the core particle and the thickness of the shell in the polymerized toner can be obtained by directly measuring the size and thickness of particles randomly selected from the observation photograph when the electron microscope can be observed. If it is difficult to observe the particle diameter of the core particle and the thickness of the shell by an electron microscope, the particle diameter is measured by the electron microscope in the same manner as above, or the particle diameter is measured by a Coulter counter at the step of forming the core particle, and then the shell After the coating on the core particles, the particle diameter can be measured once again by an electron microscope or a Coulter counter, and the average thickness can be obtained from the particle size change before and after the shell is coated. When it is difficult to measure the thickness of a shell by these methods, the thickness of a shell can be calculated from the particle diameter of a core particle and the usage-amount of the monomer which forms a shell.

In the polymerized toner of the present invention, toluene insoluble content is usually 50% by weight or less, preferably 20% by weight or less, and more preferably 10% by weight or less. When there is much toluene insoluble content, fixability tends to fall. Toluene insoluble content means that the polymer component forming the polymerized toner is placed in a wire mesh basket of 80 mesh, immersed in toluene at room temperature for 24 hours, dried in a basket with a reduced pressure dryer, and the weight after drying is measured. It is expressed in weight percent of the component.

In the polymerized toner of the present invention, the ratio (r1 / rs) of the long diameter rl and the short diameter rs is usually in the range of 1 to 1.2, preferably 1 to 1.15. As the ratio increases, the resolution of the image decreases and the friction between the polymerized toners increases when the polymerized toner is stored in the toner accommodating portion of the image forming apparatus. Therefore, external additives such as a fluidizing agent or the like tend to peel off, leading to a decrease in durability. .

The polymerized toner of the present invention can be used as a developer as it is, but may be used as a developer by adding various additives (external additives) such as a fluidizing agent as necessary. The additive is usually attached to the surface of the polymerized toner. Examples of the external additives include various inorganic particles and organic resin particles. Among these, silica particles and titanium oxide particles are preferable, and hydrophobized silica particles are particularly preferable. In order to attach the external additive to the polymerized toner, the external additive and the polymerized toner are usually put into a mixer such as a Henschel mixer and stirred.

When the polymerized toner of the present invention is used, the fixing temperature can be reduced to a low temperature of 80 to 150 ° C, preferably 80 to 130 ° C, and it is not agglomerated during storage and excellent in storageability.

Image Forming Device

An image forming apparatus to which the polymerized toner of the present invention is applied includes a photoreceptor (photosensitive drum), a means for charging a photoreceptor surface, a means for forming an electrostatic latent image on the photoreceptor surface, a means for accommodating a toner (developer), a photoreceptor by supplying toner And a means for developing an electrostatic latent image on the surface and forming a toner image and a means for transferring the toner image from the surface of the photosensitive member to the transfer material. 1 shows a specific example of such an image forming apparatus.

As shown in Fig. 1, the image forming apparatus is mounted as a photosensitive member such that the photosensitive drum 1 is free to rotate in the direction of the arrow A. As shown in FIG. The photosensitive drum 1 is formed by forming a photoconductive layer on the outer circumferential surface of the conductive support drum. The photoconductive layer is composed of, for example, an organic photoconductor, a selenium photoconductor, a zinc oxide photoconductor, an amorphous silicon photoconductor, or the like.

Around the photosensitive drum 1, along the circumferential direction thereof, a charging roll 2 as a charging means, a laser light irradiation apparatus 3 as a latent image forming means, a developing roll 4 as a developing means, and a transfer roll as a transfer means 1 ), And a cleaning apparatus (not shown) etc. are arrange | positioned as needed.

The charging roll 2 uniformly charges the photosensitive drum 1 surface to plus or minus. A voltage is applied to the charging roll 2 and the surface of the photosensitive drum 1 is charged by bringing the charging roll 2 into contact with the photosensitive drum 1 surface. The charging roll 2 may be replaced by charging means by corona discharge.

The laser irradiation apparatus 3 irradiates the surface of the photosensitive drum 1 with the light corresponding to the image signal, irradiates the surface of the photosensitive drum 1 uniformly charged in a predetermined pattern to the portion irradiated with the light. It is for forming a latent electrostatic image (in the case of a reverse phenomenon) or forming a latent electrostatic image (in the case of a normal phenomenon) in a portion where light is not irradiated. Other latent image forming means include an LED array and an optical system.

The developing roll 4 is for attaching the toner to the electrostatic latent image of the photosensitive drum 1, and in the reverse development, the toner is attached only to the light irradiation part, and in the normal development, the toner is attached only to the light non-irradiation part. A bias voltage is applied between the photosensitive drums 1.

The developing roll 4 and the supply roll 6 are provided in the casing 9 in which the toner 7 is accommodated. The developing roll 4 is arranged to be in close contact with the photosensitive drum 1 and rotated in the direction B opposite to the photosensitive drum 1. The feed roll 6 is in contact with the developing roll 4 to rotate in the same direction (C) as the developing roll, so as to supply toner to the outer circumference of the developing roll 4. In the casing 9, stirring means (stirring blades) 8 for stirring the toner are mounted.

Around the developing roll 4, the developing roll blade 5 is disposed as a layer thickness regulating means at a position between the contact point with the supply roll 6 and the contact point with the photosensitive drum 1. This blade 5 is made of conductive rubber or stainless steel, and is usually used for | 200 V | To | 600 V | Is applied. Therefore, it is preferable that the electrical resistivity of the blade 5 is 10 or less 6 square ohm-cm.

The polymerized toner 7 of the present invention is housed in the casing 9 of the image forming apparatus. The polymerization toner 7 can attach additives such as a fluidizing agent. Since the polymerized toner of the present invention has a core-shell structure, and the shell of the surface layer is formed of a polymer having a relatively high glass transition temperature, the surface toner has low adhesiveness and is prevented from agglomeration during storage in the casing 9. . In addition, since the particle size distribution is relatively sharp, the polymerized toner of the present invention can be substantially monolayered by the layer thickness regulating means 5 when forming the toner layer on the developing roll 4, whereby the image reproducibility is good. Become.

The transfer roll 10 is for transferring the toner image on the surface of the photosensitive drum 1 formed by the developing roll 4 onto the transfer material 11. Examples of the transfer material 11 include resin sheets such as paper and OHP sheets. Examples of the transfer means include a corona discharge device and a transfer belt in addition to the transfer roll 10.

The toner image transferred on the transfer material 11 is fixed on the transfer material by the fixing means. The fixing means usually consists of heating means and compression means. More specifically, the fixing means is usually composed of a combination of the heating roll (fixing roll) 12 and the pressure roll 13. The transfer material 11 to which the toner image has been transferred is passed between the heating roll 12 and the pressure roll 13 to melt the toner, and at the same time, the toner image is pressed and fixed onto the transfer material 11.

In the image forming apparatus of the present invention, the polymerized toner of the present invention is used as a toner. Thus, even when the heating temperature by the heating means is low, the toner is easily melted, and when it is lightly pressed by the pressing means, the toner becomes smooth and forms on the surface of the transfer material. Since it is fixed, printing or copying at high speed is possible. Also, the toner image fixed on the OHP sheet is excellent in OHP permeability.

The cleaning apparatus is for cleaning the transferred toner remaining on the surface of the photosensitive drum 1, and is composed of, for example, a cleaning blade or the like. When the cleaning apparatus adopts a method of cleaning at the same time as the developing roll 4, it is not necessary to provide a half seed.

Image Formation Method

In the image forming method of the present invention, the toner is attached to the surface of the photoconductor on which the electrostatic latent image is formed to make a visible image, and then the visible image is transferred to a transfer material. Use

Although an Example and a comparative example are given to the following and this invention is demonstrated to it further more concretely, this invention is not limited only to these Examples. In addition, a part and% are a basis of weight unless there is particular limitation.

The measuring method of the physical property in an Example and a comparative example is as follows.

(1) particle size of toner

The volume average particle diameter (dv) of the polymer particles, and the particle size distribution, that is, the ratio (dv / dp) of the volume average particle diameter and the number average particle diameter (dp) are measured by a multisizer (manufactured by Coulter Shah). The measurement by this multi-siter is performed on condition of aperture diameter: 50 micrometers, medium: isotone II, and the number of particles measured: 50000.

(2) the thickness of the shell

When the thickness of the shell is thick, it can be measured by a multisizer or an electron microscope, but in the present embodiment, the shell thickness is calculated using the following equation.

Shell thickness (µm) = dr (1 + s / 100) ¹ / ³ -dr

Where dr is the radius of the core particles before the addition of the polymerizable monomer for shell (the diameter of 1/2 of the volume average particle diameter measured by the multisizer, and s is the number of added parts of the polymerizable monomer for the shell (100 weight of polymerizable monomer for core) Number of copies of wealth).

(3) Volume specific resistance of toner

The volume specific resistance of the toner is measured using a dielectric loss measuring instrument (trade name TRS-10 type, manufactured by Ando Odenkisha Co., Ltd.) under a temperature of 30 ° C. and a frequency of 1 kHz.

(4) fixing temperature of toner

A commercially available non-magnetic one-component developing printer (4 organs) can be retrofitted to change the temperature of the fixing roll portion. This toner is used for image evaluation of the toner. The temperature of 80% of fixation rate is evaluated by fixing temperature. The fixing test is performed by changing the temperature of the fixing roll of the printer and measuring the fixing rate at each temperature to obtain the relationship between the temperature and the fixing rate. The fixation rate is calculated as the ratio of the image density before and after the tape peeling operation of the black beta area on the test paper printed by the retrofit printer. If the image concentration before tape peeling is before ID and the image concentration after tape peeling is after ID, the fixation rate can be obtained by the following equation.

Settlement Rate (%) ＝ (After ID / Before ID) × 100

Herein, the black beta region refers to a region controlled to attach toner to all dots in the region. Tape peeling operation is to apply adhesive tape (Scotch Mending Tape 810-3-18 manufactured by Sumidomo 3M Co., Ltd.) to the measurement part of the test paper, extrude it at a constant pressure, and then apply the adhesive tape along the paper at a constant speed. It is a series of operations to peel. In addition, the image density is measured using a reflective image density meter manufactured by McBeth.

(5) Toner Storage

The storage stability is evaluated by placing the toner sample in a sealed container, sealing it, immersing it in a constant temperature water bath controlled at 55 ° C, and taking out a certain amount of time and measuring the weight of the aggregated toner. The sample taken out of the container is transferred onto a 42-mesh sieve so as not to destroy the structure as much as possible.Then, the toner remaining on the sieve is vibrated for 30 seconds by setting the intensity of vibration to 4.5 in the REOSTAT of the powder measuring instrument (manufactured by Hosogawa Micron). The weight of the toner is measured to be the weight of the aggregated toner. The agglomeration rate (% by weight) of the toner is calculated from the weight of the aggregated toner and the number of samples.

Toner retention is evaluated in the following four steps.

◎: Coagulation rate is less than 5% by weight

(Circle): Cohesion rate is 5 weight% or more and less than 10 weight%

(Triangle | delta): 10% by weight or more and less than 50% by weight

X: Coagulation rate is 50 weight% or more

(6) OHP permeability

The temperature of the fixing roll of the remodeled printer was set to 150 ° C, printed using a commercially available OHP (Transparency) manufactured by Uchida-O-Kyosha, and the OHP permeability of the toner was evaluated. It is visually observed whether the factor penetrates the OHP sheet, and the permeation (circle) or non-transmission (x) is evaluated.

(7) toner charging amount

The amount of charge in each environment of L / L (temperature 10 ° C., humidity 20% RH) and H / H (temperature 35 ° C., humidity 80% RH) is measured to evaluate the situation of environmental variation.

The charge amount of the toner is placed in a commercial printer (4 organs) under the above conditions, and the toner is allowed to stand for one day and night, and then, after printing five sheets of halftone printing patterns, the toner on the developing roll is charged with a charge amount measuring device. The amount of charge per unit weight is measured by the amount of suction and the amount of suction.

(8) Image quality evaluation

Continuous factoring was carried out from the beginning, and the factor concentration was 1.3 or more with a reflectance densitometer (manufactured by Macbeth), and the number of prints where the cloudyness of the non-image area was kept at 10% or less with a white colorimeter (manufactured by Nippon Denshoku) was counted. Conduct evaluation.

(Circle): When the said number of sheets of prints is 10,000 sheets or more

(Triangle | delta): When the said number of sheets is more than 5 ceilings and less than 10,000 sheets

X: when the number of prints is less than 5 ceiling

Example 1

Core polymerizable monomer consisting of 78 parts of styrene and 22 parts of n-butyl acrylate (calculated Tg = 50 DEG C of the obtained copolymer), 7 parts of carbon black (manufactured by Deg Sasha, trade name Printex 150 T), charge control agent (Hodoya) Kagakusha Co., Ltd. brand name Spiron Black TRH) 1 part, divinylbenzene 0.3 part, polymethacrylic acid ester macromonomer (made by Toagosei Chemical Co., Ltd., AA6, Tg = 94 degreeC) 0.8 part, pentaeryt A homomixer (TK formula, manufactured by Torsh Shugka Kosha Co., Ltd.) capable of mixing 10 parts of lititol tetrastearate (about 60% of stearic acid) and 4 parts of t-butylperoxy-2-ethylhexanoate with high shear force The mixture is stirred and mixed at a rotational speed of 12000 rpm to homogeneously disperse to obtain a polymerizable monomer composition (mixture) for the core.

On the other hand, 10 parts of methyl methacrylate (calculated Tg = 105 degreeC) and 100 parts of water are micro-distilled-processed by the ultrasonic emulsifier, and the aqueous dispersion of the polymerizable monomer for shell is obtained. The particle size of the droplets of the polymerizable monomer for shell was added to the obtained droplets in a 1% sodium hexametaphosphate aqueous solution at a concentration of 3%, and D ₉₀ was 1.6 µm as measured by a micro track particle size distribution analyzer.

Meanwhile, magnesium hydroxide colloid (I A colloidal) dispersion of water-soluble metal hydroxides is prepared. The particle size distribution of the colloid produced was measured by a micro track particle size distribution analyzer (manufactured by Nikkisosha). As a result, D ₅₀ (50% cumulative value of the number particle size distribution) was 0.38 µm and D ₉₀ ( ₉₀ of the number particle size distribution). % Cumulative value) was 0.82 mu m. In the measurement by a micro track particle size distribution analyzer, measurement was carried out under the conditions of measuring range = 0.12 to 704 µm, measuring time = 30 seconds, and medium = ion exchanged water.

The said polymerizable monomer composition for cores is thrown into the magnesium hydroxide colloid dispersion obtained by the above, high shear stirring is carried out at the rotation speed of 12000 rpm using a TK type homomixer, and the droplet of the polymerizable monomer composition for cores is granulated. The aqueous dispersion of the granulated monomer composition was placed in a reactor equipped with a stirring blade, and the polymerization reaction was initiated at 90 ° C., when the polymerization conversion rate reached almost 100%, the polymerizable monomer for shell and 1 part of 1% aqueous potassium persulfate solution were added. After adding and continuing reaction for 5 hours, reaction is stopped and the aqueous dispersion of core-shell polymer particle is obtained.

The volume average particle diameter (dv) measured by taking out core particle immediately before adding the polymerizable monomer for shell was 5.7 micrometers, and the volume average particle diameter (dv) / number average particle diameter (dp) was 1.32. Shell thickness was 0.09 micrometer, rl / rs was 1.1, and toluene insoluble content was 2%.

While washing the aqueous dispersion of the core-shell polymer particles obtained by the method described above, the system pH was adjusted to 4 or less with sulfuric acid, followed by acid washing (25 ° C. for 10 minutes), and water was separated by filtration. After that, freshly added 500 parts of ion-exchanged water was rethrillered and washed with water. Thereafter, dehydration and water washing are repeated several times, and the solid content is separated by filtration, and then dried overnight at 45 ° C. in a drier to obtain polymer particles (polymerized toner).

To 100 parts of the core-shell polymerized toner obtained by the method described above, 0.3 part of hydrophobized colloidal silica (trade name: R-972, manufactured by Nippon Aerogesia) was added, mixed using a Henschel mixer, and then mixed with a nonmagnetic one component. A developer (only called developer or toner) is prepared. The volume specific resistance of the toner obtained in this manner was measured to be 11.3 log Pa · cm.

It was 120 degreeC when the fixing temperature was measured using the toner obtained by the above-mentioned method. The toner of this toner was very good (evaluation = ◎). In image evaluation, an image with high image density and very good resolution without blur and unevenness was obtained. The results are shown in Table 1.

Example 2

A polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that the amount of pentaerythritol tetrastearate used in Example 1 was changed to 5 parts. In image evaluation, an image with high image density and very good resolution without blur and unevenness was obtained. The results are shown in Table 1.

Example 3

A polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that the pentaerythritol tetrastearate used in Example 1 was changed to glycerol triarachinic acid (arachnic acid purity of about 60%). The results are shown in Table 1.

Comparative Example 1

A polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that the pentaerythritol tetrastearate used in Example 1 was changed to paraffin wax having a melting point of 60 ° C. The results are shown in Table 1.

Comparative Example 2

A polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that the pentaerythritol tetrastearate used in Example 1 was changed to a low molecular weight polypropylene having a number average molecular weight of 2200. The results are shown in Table 1.

Example Comparative example One 2 3 One 2 Core particle dv [μm] dv / dp 5.71.32 5.71.28 6.11.25 6.51.35 6.01.22 Polymer Particle Shell Thickness [µm] Toluene Insoluble Content [%] 0.092 0.093 0.093 0.102 0.104 Toner Evaluation dv [μm] dv / dp Volume Intrinsic Resistance [logΩcm] Settling Temperature [° C] Storage L / L Charge [μc / g] H / H Charge [μc / g] 5.91.3011.3120 ◎ -26-16 ○ 5.91.3011.4130 ◎ -24-25 ○ 6.31.2811.2130 ◎ -28-25 ○ 6.71.3611.0150 △ -25-20 × 6.21.2411.4160 △ -27-25 △

Comparative Example 3

4 parts of saturated polyester, 83 parts of styrene, 17 parts of butyl acrylate, 7 parts of carbon black, 1 part of salicylic acid metal compound and 10 parts of pentaerythritol dibehenate diacetate were dispersed using a TK type homomixer, 5 parts of 2'-azobis (2,4-dimethylvaleronitrile) are added to prepare a polymerizable monomer composition, and then the composition is granulated, and then the temperature is raised to 60 ° C and polymerized for 10 hours. After polymerization, washing and drying are carried out to obtain polymer particles (polymerized toner). A developer (toner) is obtained in the same manner as in Example 1 using this polymerization toner. The results are shown in Table 2.

Example 4

In Example 1, the polymerization toner and the developer (toner) were prepared in the same manner as in Example 1, except that 10 parts of methyl methacrylate used for the polymerizable monomer for shell was changed to 9 parts of methyl methacrylate and 1 part of butyl acrylate. Get The results are shown in Table 2.

Example 5

In Example 1, 10 parts of styrene were used instead of 10 parts of methyl methacrylate used for the polymerizable monomer for shell, and 20 parts of methanol were added just before adding the polymerizable monomer for shell, and it was the same method as Example 1 A polymerized toner and a developer (toner) are obtained. The results are shown in Table 2.

Example 6

In Example 1, 2,2- azobisisobutyronitrile was used instead of t-butylperoxy-2-ethylhexanoate used as a polymerization initiator of the polymerizable monomer for cores, and the reaction temperature was 75 ° C. A polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except for the change. The results are shown in Table 2. When fixing is performed using this toner, a slight odor is generated.

Example 7

In Example 1, a polymerized toner and a developer (toner) are obtained in the same manner as in Example 1 except that the polymerizable monomer for shell is added without performing an ultrasonic emulsifier treatment. The results are shown in Table 2.

Example Comparative example 4 5 6 7 3 Core particle dv [μm] dv / dp 6.01.27 6.11.31 5.91.35 6.51.40 6.21.38 Polymer Particle Shell Thickness [µm] Toluene Insoluble Content [%] 0.103 0.103 0.095 0.104 0.094 Toner Evaluation dv [μm] dv / dp Volume Intrinsic Resistance [logΩcm] Settling Temperature [° C] Storage L / L Charge [μc / g] H / H Charge [μc / g] 6.21.2711.3120 ◎ -27-22 ○ 6.31.3111.4130 ◎ -30-27 ○ 6.11.3311.2130 ◎ -22-18 ○ 6.71.4011.1130 ○ -23-19 ○ 6.41.3711.1140 × -20-20 ×

Example 8

In Example 1, a polymerization toner and a developer (toner) were obtained in the same manner as in Example 1 except that the butyl acrylate used for the polymerizable monomer for core was changed to 2-ethylhexyl acrylate. The results are shown in Table 3.

Example 9

In Example 1, a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 5 parts of magenta pigment (Pigment Red 122) were used instead of 7 parts of carbon black. The results are shown in Table 3.

Example 10

In Example 1, a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 5 parts of yellow quinophtharon pigments (Pigment Yellow 138) were used instead of 7 parts of carbon black. The results are shown in Table 3.

Example 11

In Example 1, a polymerization toner and a developer (toner) were obtained in the same manner as in Example 1 except that 5 parts of cyan pigment (Pigment Blue 15: 3) was used instead of 7 parts of carbon black. The results are shown in Table 3.

Comparative Example 4

In Example 1, a polymerized toner and a developer (toner) were obtained in the same manner as in Comparative Example 1 except that 5 parts of magenta pigment (Pigment Red 122) were used instead of 7 parts of carbon black. The results are shown in Table 3.

Example Comparative example 8 9 10 11 4 Core particle dv [μm] dv / dp 6.31.21 6.11.18 6.21.25 6.51.31 5.91.27 Polymer Particle Shell Thickness [µm] Toluene Insoluble Content [%] 0.103 0.104 0.105 0.106 0.094 Toner evaluation dv [μm] dv / dp Volume specific resistance [logΩcm] Settling temperature [° C] Storage L / L charge amount [μc / g] H / H charge amount [μc / g] OHP permeability evaluation 6.51.2211.4120 ◎ -28-25- ○ 6.31.1712.5130 ◎ -32-30 ○○ 6.41.2412.4120 ◎ -34-31 ○○ 6.71.2911.6130 ◎ -28-25 ○○ 6.11.2712.4130 △ -33-29 ○ ×

Example 12

In Example 1, a polymerization toner and a developer (toner) are obtained in the same manner as in Example 1 except that pentaerythritol tetramyristate is used instead of pentaerythritol tetrastearate.

The volume average particle diameter (dv) measured by taking out core particle immediately before adding the polymerizable monomer for shell was 5.8 micrometers, and the volume average particle diameter (dv) / number average particle diameter (dp) was 1.22. Shell thickness was 0.09 micrometer, rl / rs was 1.1, and toluene insoluble content was 2%.

The volume specific resistance of the nonmagnetic one-component developer (toner) to which the hydrophobized colloidal silica was added to the obtained polymerized toner was 11.3 logPa · cm. It was 120 degreeC when the fixing temperature was measured using this toner. The toner of this toner was very good (evaluation = ◎). The L / L charge of this toner was -28 µc / g, and the H / H charge of -25 µc / g. In image evaluation, an image (image quality evaluation = ○) with high image density and very good resolution without blur and unevenness was obtained.

And, compared to pentaerythritol tetrastearate, pentaerythritol tetramyristate is superior in solubility to polymerizable monomers and does not need to be pre-pulverized or melted to improve solubility at room temperature.

According to the present invention, there is provided a polymerized toner having a low fixing temperature and uniform meltability, and having excellent storage property, and a method of manufacturing the same. By using the polymerized toner of the present invention, it is possible to speed up copying and printing, full color, and energy saving. In addition, the polymerized toner of the present invention exhibits excellent water permeability when printed and fixed on an OHP sheet. The polymerized toner of the present invention can form a high quality image without blurring and lowering of the printing concentration. According to the present invention, there is provided an image forming method using a polymerized toner having such excellent characteristics and an image forming apparatus containing the polymerized toner.

Claims (33)

The core particles composed of colored polymer particles containing a polyfunctional alcohol compound and a polyfunctional polyfunctional ester compound formed from a trifunctional or higher polyhydric alcohol and a carboxylic acid are polymers having a glass transition temperature higher than the glass transition temperature of the polymer component constituting the core particles. Polymerized toner with a core-shell structure covered with a shell made of a shell. The polymerized toner according to claim 1, wherein the core particle is a colored polymer particle obtained by suspension polymerization of a polymerizable monomer composition containing a polymerizable monomer for core, a polyfunctional ester compound formed of polyhydric alcohol and carboxylic acid, and a colorant. The colored polymer particle according to claim 1, wherein the core particle is obtained by suspension polymerizing a polymerizable monomer composition containing a polymerizable monomer for core, a polyfunctional ester compound formed of polyhydric alcohol and carboxylic acid, and a colorant in the presence of a macromonomer. Phosphorus polymerization toner. The polymerized toner according to claim 1, wherein the shell is a polymer layer formed on the surface of the core particles by suspending and polymerizing the polymerizable monomer for shell in the presence of the core particles. The polymerized toner according to claim 1, wherein the average particle diameter of the core particles is 0.5 to 20 m, and the average thickness of the shell is 0.001 to 1 m. The polymerized toner according to claim 1, wherein the volume average particle diameter is 2 to 20 µm and the particle size distribution (volume average particle diameter / number average particle diameter) is 1.6 or less. The polymerized toner according to claim 1, wherein the content of the polyfunctional ester compound is 0.1 to 40 parts by weight per 100 parts by weight of the polymer component constituting the core particles. According to claim 1, wherein the polyfunctional ester compound is represented by the following formula (1) [Formula 1] (However, R ¹ , R ² , R ³ and R ⁴ are each independently an alkyl group or a phenyl group, and the alkyl or phenyl group has 10 to 30 carbon atoms.) Polymerized toner that is a compound represented by. 9. The polymerized toner according to claim 8, wherein the polyfunctional ester compound is pentaerythritol tetrastearate or pentaerythritol tetramyristate. (1) In an aqueous dispersion medium containing a dispersant, a polyfunctional ester compound formed of a trifunctional or higher polyhydric alcohol and a carboxylic acid, a colorant, and a polymerizable monomer for core capable of forming a polymer having a glass transition temperature of 80 ° C. or less Suspending polymerization of the polymerizable monomer composition to prepare a core particle consisting of colored polymer particles, and (2) in the presence of the core particles, the glass transition temperature higher than the glass transition temperature of the polymer component constituting the core particles A method for producing a polymerized toner having a core-shell structure in which a shell composed of a polymer layer covering the core particles by suspending and polymerizing a polymerizable monomer for shell capable of forming a polymer having. The production method according to claim 10, wherein in step (1), the polymerizable monomer composition is suspended and polymerized in the presence of a macromonomer to prepare core particles composed of colored polymer particles. The production method according to claim 10, wherein the content of the polyfunctional ester compound is 0.1 to 40 parts by weight per 100 parts by weight of the polymerizable monomer for core. The method of claim 10, wherein the polyfunctional ester compound is represented by the following formula (1) [Formula 1] (However, R ¹ , R ² , R ³ and R ⁴ are each independently an alkyl group or a phenyl group, and the alkyl or phenyl group has 10 to 30 carbon atoms.) Method of producing a compound represented by. The production method according to claim 13, wherein the polyfunctional ester compound is pentaerythritol tetrastearate or pentaerythritol tetramyristate. The production method according to claim 10, wherein the polymerizable monomer composition further contains a crosslinkable monomer. The method according to claim 11, wherein the macromonomer has a number average molecular weight of 1,000 to 30,000 and has a glass transition temperature higher than the glass transition temperature of the polymer obtained by polymerizing the polymerizable monomer for core. The method according to claim 11, wherein the amount of the macromonomer used is 0.01 to 10 parts by weight per 100 parts by weight of the polymerizable monomer for the core. The production process according to claim 10, wherein in the step (1), the polymerizable monomer composition is suspended and polymerized with an oil-soluble radical polymerization initiator in an aqueous dispersion medium. 19. The method according to claim 18, wherein the oil-soluble radical polymerization initiator is an organic peroxide having a temperature of a half life of 10 hours at 60 to 80 ° C and a molecular weight of 250 or less. The production process according to claim 10, wherein in step (1), suspension polymerization is carried out in an aqueous dispersion medium containing a colloid of a poorly water-soluble metal hydroxide as a dispersant. The colloid of the poorly water-soluble metal hydroxide according to claim 20, wherein the 50% cumulative value (D ₅₀ ) of the number particle size distribution is 0.5 µm or less, and the 90% cumulative value (D ₉₀ ) of the number particle size distribution is 1 µm or less. Phosphorus manufacturing method. The production method according to claim 20, wherein the colloid of the poorly water-soluble metal hydroxide is a colloid of the poorly water-soluble metal hydroxide obtained by adjusting the pH of the aqueous solution of the water-soluble polyvalent metal compound to 7 or more. 21. The method according to claim 20, wherein the colloid of the poorly water-soluble metal hydroxide is a colloid of the poorly water-soluble metal hydroxide produced by reacting a water-soluble polyvalent metal compound with an alkali metal hydroxide in an aqueous phase. 11. The process according to claim 10, wherein a mixed liquid containing at least a polyfunctional ester compound, a colorant, a polymerizable monomer for a core, and a radical polymerization initiator is prepared in step (1), and then the mixed liquid is added to an aqueous dispersion medium containing a dispersant. A method for producing a mixture by adding the mixture, stirring and granulating the fine droplets, and then suspending polymerization at a temperature of 30 to 200 캜. The colored polymer according to claim 10, wherein in the step (1), the volume average particle diameter (dv) is 0.5 to 20 µm, and the ratio (dv / dp) of the volume average particle diameter (dv) and the number average particle diameter (dp) is 1.7 or less. The manufacturing method which prepares the core particle which consists of particle | grains. The production method according to claim 10, wherein in the step (2), the polymerizable monomer for shell is suspended as a droplet having a number average particle diameter smaller than that of the core particles. The method according to claim 10, wherein the polymerizable monomer for shell is a monomer having a solubility in water of 20 ° C of at least 0.1% by weight. The polymerizable monomer for shell is a monomer having a solubility in water of 20 ° C of less than 0.1% by weight, and in step (2), the solubility of the polymerizable monomer for shell and water of 20 ° C is 5. Suspension polymerization by adding an organic solvent by weight or more. The production method according to claim 10, wherein in the step (2), the polymerizable monomer for shell and the charge control agent are added to suspend polymerization. The production method according to claim 10, wherein in the step (2), the polymerizable monomer for shell is suspended and polymerized with a water-soluble radical polymerization initiator. The manufacturing method of Claim 10 which forms the shell which consists of a polymer layer of average film thickness 0.001-1 micrometer in a process (2). An image forming method comprising attaching a toner to a surface of a photoconductor on which an electrostatic latent image is formed to make a visible image, and transferring the visible image to a transfer material, wherein the toner is a polyfunctional formed of a trifunctional or higher polyhydric alcohol and carboxylic acid as a toner. A core-shell polymerized toner in which a core particle composed of colored polymer particles containing an ester compound and a colorant is coated with a shell made of a polymer having a glass transition temperature higher than the glass transition temperature of the polymer component constituting the core particle. An image forming method, characterized by using. A photosensitive member, means for charging the photosensitive member surface, means for forming an electrostatic latent image on the photosensitive member surface, means for accommodating toner, means for supplying the toner and developing an electrostatic latent image on the photosensitive member surface to form a toner image, and the toner image An image forming apparatus comprising means for transferring from a photosensitive member surface to a transfer material, wherein the means for accommodating toner comprises a polyfunctional ester compound formed of a trifunctional or higher polyhydric alcohol and a carboxylic acid, and colored polymer particles containing a colorant. An image forming apparatus, wherein the core particles contain a polymerized toner having a core-shell structure, which is covered with a shell made of a polymer having a glass transition temperature higher than the glass transition temperature of the polymer component constituting the core particles.