JP2006349722A - Method for manufacturing toner for electrostatic image development and toner for electrostatic image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic image development which satisfies both image quality and storage stability while ensuring low-temperature fixing performance, and a method for manufacturing the toner for electrostatic image development which ensures a simplified manufacturing process and a shortened manufacturing time. <P>SOLUTION: The method for manufacturing the toner for electrostatic image development includes: an agglomeration step of forming agglomerated particles by agglomerating a plurality of resin particles with anions and adjusting the particle diameter; and an aging step of adjusting the circularity of the agglomerated particles, wherein in the aging step, the agglomerated particles are heated and stirred in an alkaline solution of pH 8-14 in the presence of polyvalent metal ions exist in the medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an electrostatic image developing toner and an electrostatic image developing toner.

  From the viewpoint of high image quality, a chemical process toner is attracting attention. Among these, the emulsion association method is preferably carried out because of controllability of the toner circularity.

  Emulsion association toners are dispersed and stabilized in an aqueous medium by allowing ionic groups to exist on the surface. However, the toner performance includes charging performance such as the presence of ionic groups causing a difference in charging environment. Will cause adverse effects.

  Therefore, as a post-treatment after toner particle generation, the influence of the ionic group was made as small as possible by removing the surfactant or coordinating the metal so as not to dissociate the ionic group (for example, Patent Documents 1 and 2).

  On the other hand, from the viewpoint of energy saving, there is a problem of low-temperature fixing capable of reducing power consumption. As a toner for low-temperature fixing, a core with a low glass transition temperature core layer coated with a shell layer having a high glass transition temperature is used. Development of a shell-structured toner has been advanced, and in particular, formation of a shell layer has become a problem.

  The function of the shell layer is agglomeration resistance, but in the conventional method of forming a shell layer by adsorbing and fusing resin particles to the core particles prepared by the emulsion association method, a high molecular weight resin is added to the shell layer. If it is adopted, there has been a problem that it takes time to fuse the resin particles, that is, to make the toner spherical.

As described above, the toner production method that combines the problem of the charging property caused by the ionic group in the toner of the chemical production method and the easy production method of the toner having the high molecular weight shell layer satisfying the low-temperature fixing performance, and the toner are still It was not found.
JP 2001-255700 A JP-A-9-114125

  In the present invention, it is possible to provide a toner production method and a toner that can eliminate the deterioration of charging performance due to the ionic groups present in the toner as described above and can easily form a high molecular weight shell layer. Objective.

  The object of the present invention is achieved by adopting the following configuration.

(Claim 1)
An aggregation step of aggregating a plurality of resin particles having anions to adjust the particle size to form aggregated particles;
In the method for producing a toner for developing an electrostatic image having a ripening step of adjusting the circularity of the aggregated particles,
In the aging step, under conditions where polyvalent metal ions are present in the medium,
A method for producing a toner for developing an electrostatic charge image, comprising heating and stirring in an alkaline solution having a pH of 8 to 14.

(Claim 2)
An agglomeration step of aggregating a plurality of resin particles having a hydrophilic resin and a hydrophobic resin to adjust the particle diameter;
In the method for producing a toner for developing an electrostatic image having a ripening step of adjusting the circularity of the aggregated particles,
In the aging step, under conditions where polyvalent metal ions are present in the medium,
A method for producing a toner for developing an electrostatic charge image, comprising heating and stirring in an alkaline solution having a pH of 8 to 14.

(Claim 3)
A toner for developing electrostatic images obtained by aggregating a plurality of resin particles having anions, wherein a high molecular weight layer is formed on the surface of the toner for developing electrostatic images by an ion crosslinking reaction. Toner for developing electrostatic image.

  The present invention eliminates charging performance deterioration due to ionic groups present in an electrostatic charge image developing toner (hereinafter also simply referred to as “toner”), and can easily form a high molecular weight shell layer. And to provide toner.

  The inventors of the present invention have studied a toner production method and a toner capable of eliminating a deterioration in charging performance due to an ionic group present in the toner and easily forming a high molecular weight shell layer.

  As a result of various investigations, in the emulsion association method toner, without performing the step of forming the shell layer by adding the particles for the shell after forming the core particles, the solution in the aging step at the time of producing the toner base is adjusted to alkali, By stirring in a heated state, an ionic cross-linking reaction is promoted by a reaction between an anion present on the surface of the toner base and a polyvalent metal ion, and charging performance is not deteriorated due to an ionic group present in the toner. A toner satisfying both low-temperature fixability and storage stability could be produced by making the resin in the vicinity (near) hard (high molecular weight).

  In the conventional technique of adjusting the pH after forming toner particles in water, the ion crosslinking reaction on the outermost surface of the toner is limited. In the present invention, the pH is adjusted to 8 to 14 in the toner ripening step, and the ion crosslinking is performed. By proceeding with the reaction, a shell layer made of a high molecular weight resin can be provided.

  The alkaline solution referred to in the present invention refers to a solution having a pH of 8 to 14, and preferably has a pH of 9 to 11. As a means for making the alkaline solution, a method of adding a metal hydroxide such as sodium hydroxide to the main solution is preferable.

  Ionic crosslinking is a crosslinking reaction formed between an anion and a polyvalent metal ion. Examples of the anion include a carboxyl group, a sulfone group, a phosphate group, and a hydroxyl group. On the other hand, examples of polyvalent metal ions include divalent cations such as Ca, Ba, Mg, Sr, and Fe, and trivalent cations such as Al and Fe. Preferably, Mg and Al are used.

  The reaction temperature of the ionic crosslinking reaction is considered to be the same as the appropriate temperature in the step of adjusting the circularity of the toner in the emulsion association method, and “glass transition temperature + 20 ° C. or higher” of the binder resin is preferable. By setting the liquid temperature within this range, the formation of the layer subjected to the ion crosslinking reaction can be favorably progressed.

  The reason for making the alkaline solution is that when it is made alkaline, the hydrophilic group is ionized, leading to an increase in anions used for metal crosslinking, and an ionic crosslinking reaction is effectively performed.

  The reason for stirring with heating is that, under heating conditions, the fluidity inside the resin of the colored particles is imparted, so that hydrophilic groups (anions) are likely to be present on the particle surface.

  The present invention produces resin particles containing anions, aggregates the resin particles and colorant particles to produce colored particles, and the colored particles are contained in an alkaline solution having a pH of 8 to 14 having polyvalent metal ions. In this method, a toner is manufactured by heating and stirring in order to form a crosslinked structure with anions and polyvalent metal ions, and hardening the resin in the vicinity of the particle surface (high molecular weight).

  According to this toner manufacturing method, a hard layer that acts as a shell layer of a core-shell structure can be formed by performing an ionic crosslinking reaction in the vicinity of the surface of the colored particles in an alkaline solution. Can be produced.

  In addition, by using resin particles having a hydrophilic resin and a hydrophobic resin during the aggregation step, a core / shell structure of a hydrophobic resin-based core and a hydrophilic resin-based shell can be formed. The carboxyl group of the monomer can be effectively used for ionic crosslinking.

  In a known method for preparing a toner having a core / shell structure, resin particles obtained by polymerizing a polymerizable monomer in a solution are aggregated and fused to form a core portion, and a resin particle solution is further added to form a core portion. Since the shell layer is formed thereon, the process becomes complicated and takes time. Furthermore, the resin particles for the core part and the resin particles for the shell part must be prepared, and the apparatus becomes large.

  Further, when a high molecular weight resin is used for the resin particles for the shell portion, it becomes difficult to fuse the resin, and it takes a long time to form the shell layer. Therefore, in the manufacturing method of the present invention, since it is possible to have a high molecular weight shell layer without having a shelling process, the apparatus can be simplified, the process can be shortened, and the time can be shortened. .

  As for the thickness of the layer in which the crosslinked structure was formed, 50-300 nm is preferable.

  The layer thickness can be measured with a scanning probe microscope (SPM).

  The thickness of the shell layer was measured using a scanning probe microscope SPI3800N and a multifunctional unit SPA400 (manufactured by SII Nanotechnology).

  For the measurement sample, a block was used in which the toner was embedded in an epoxy resin, cured for 24 hours at 60 ° C., and then a flat surface was cut out using a microtome provided with diamond teeth so that the cross section was smoothed and the cross section of the toner could be observed. .

  The scanner is FS-100N (in-plane 100 μm, vertical 15 μm), the micro cantilever is silicon nitride SN-AF01 (spring constant 0.08 N / m), and the measurement mode is micro viscoelastic mode (VE-AFM) It was. The excitation frequency is set to 3 to 5 kHz and the excitation amplitude is set to 4 to 6 nm, and four screens of the shape image, amplitude A, Asin δ, and Acos δ are simultaneously measured in a measurement area of 10 μm × 10 μm, and the shell layer is visually observed in the amplitude image. Confirmed by observation, the distance from the outermost surface of the toner to the core was measured, and the average value was calculated as the shell layer thickness. Specifically, it is calculated from an intersection with a straight line passing through the center of the toner, and the straight lines are eight straight lines provided radially at equal intervals from the center. The number of toners to be measured is at least 50 or more. The measurement environment was 25 ° C. ± 5 ° C.

  FIG. 1 is a schematic diagram illustrating an example of a toner obtained by the toner manufacturing method of the present invention.

  FIG. 2 is a schematic diagram showing an example of a process for forming a conventional toner having a core / shell structure as a comparative example.

  In FIGS. 1 and 2, 10 is a toner base, 11 is a resin particle, 12 is a colorant particle, 13 is a color particle, 21 is a core part, 22 is a layer having a crosslinked structure, and 23 is a shell layer.

  In the toner production method of the present invention, as shown in FIG. 1, first, resin particles and colorant particles are associated to form colored particles, and these colored particles are heated and stirred in an alkaline solution having a pH of 8 to 14. And aging process.

  In the aging step, the anion in the resin near the surface of the colored particles and the metal ion of the polyvalent metal compound are subjected to a crosslinking reaction to form a layer having a high molecular weight crosslinked structure.

  On the other hand, in the conventionally known core / shell structure toner manufacturing method, resin particles and colorant particles are aggregated to form colored particles, and further, the resin particles are added to the color particles for aggregation, followed by aging to obtain a toner base. Since it is formed, the process becomes complicated and time is required.

<Production of toner>
The toner according to the present invention preferably has a small particle size and a uniform distribution. Further, the toner according to the present invention is preferably a chemical toner produced by a chemical method capable of efficiently obtaining a toner having a small particle diameter.

The toner according to the present invention has a median particle diameter (D ₅₀ ) on a volume basis of preferably 3 to 8 μm, and more preferably 4 to 7 μm.

  Next, the method for producing the toner of the present invention will be described in detail.

  The method for producing a toner of the present invention is to produce a colored particle by associating at least resin particles having an anion and a colorant particle, and then agitating the colored particle by heating and stirring in an alkaline solution. It is a manufacturing method to do.

  The emulsion association method is a method in which resin particles are prepared by salting out / fusion in an aqueous medium. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, dispersed particles of constituent materials such as resin particles and a colorant, or a method of salting out, agglomerating and fusing a plurality of particles composed of a resin and a colorant, etc., particularly in water using an emulsifier Then, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the formed polymer is heated and fused at a temperature higher than the glass transition temperature of the polymer itself to gradually grow the particle size while forming fused particles. When the desired particle size is reached, a large amount of water is added to stop particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated in a fluid state while containing water. By drying, the toner according to the present invention can be formed.

  In the toner manufacturing method of the present invention, a release agent is dissolved or dispersed in a polymerizable monomer, and then finely dispersed in an aqueous medium, and the polymerizable monomer is polymerized by a miniemulsion polymerization method. A method in which the composite resin particles and the colorant particles formed through the steps are salted out / fused is preferably used.

  Next, an example of a method for producing toner by the emulsion association method will be described in detail.

This toner manufacturing method is manufactured through the following steps.
(1) Dissolution / dispersion step for dissolving or dispersing the release agent in (radical) polymerizable monomer (2) Polymerization step for preparing a dispersion of resin particles by polymerizing the dissolved / dispersed polymerizable monomer (3) Aggregation step of aggregating resin particles and colorant particles in an aqueous medium to obtain colored particles (4) The colored particles are heated and stirred in an alkaline solution to cure the surface of the colored particles to disperse the toner base. (5) Cooling step for cooling the dispersion of the toner base (6) Solid-liquid separation of the toner base from the cooled dispersion of the toner base, and removing the surfactant and the like from the toner base Washing step (7) Drying step of drying the washed toner base If necessary, (8) A step of adding an external additive to the dried toner base may be included.

  Hereinafter, each step will be described.

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

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

  By this polymerization step, resin particles containing a release agent and a binder resin are obtained. Such resin particles may be colored particles or non-colored particles. The colored resin particles can be obtained by polymerizing a monomer composition containing a colorant. In addition, when using non-colored resin particles, in the aggregation step described later, the dispersion of the colorant particles is added to the dispersion of the resin particles to aggregate the resin particles and the colorant particles. It can be colored particles.

[Aggregation process]
The aggregation step is a step of forming colored particles using resin particles (colored or non-colored resin particles) obtained by the polymerization step and colorant particles. In the aggregation step, resin particles and colorant particles can be aggregated together with release agent particles, internal additive particles such as charge control agents, and the like.

  The colorant particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gorin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, or the like. Examples thereof include a medium type disperser.

  The colorant particles may be surface modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the molecular weight solution, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is separated by filtration, washed and filtered with the same solvent, and dried to obtain a colorant (pigment) treated with the surface modifier.

  A preferred aggregating method is to add a salting-out agent composed of an alkali metal salt, an alkaline earth metal salt, or the like as an aggregating agent having a critical aggregation concentration or more in water in which resin particles and colorant particles are present, In this method, aggregation is carried out by heating to a temperature above the glass transition point of the resin particles and above the melting peak temperature (° C.) of the release agent.

[Aging process]
In the aging step, the colored particles obtained above are heated and stirred in an alkaline solution to adjust the circularity of the colored particles, and the anion contained in the resin near the particle surface and the polyvalent metal ions in the alkaline solution To form a crosslinked shell layer to obtain a dispersion of a toner base having a core / shell structure.

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

[Solid-liquid separation and washing process]
In this solid-liquid separation / washing step, a solid-liquid separation process for solid-liquid separation of the toner base from the dispersion of the toner base cooled to a predetermined temperature in the above-described step, and a solid-liquid separated toner cake (in a wet state) A cleaning process is performed to remove deposits such as a surfactant and a salting-out agent and an alkali agent used in the aging step from an aggregate obtained by agglomerating a toner base in a cake form.

  In the washing treatment, the filtrate is washed with water until the electric conductivity of the filtrate reaches 10 μS / cm.

  Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.

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

[External process]
This step is a step in which an external additive is mixed with the dried toner base as necessary to produce a toner.

  As an external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

  Next, the compound constituting the toner will be described.

(Binder resin)
The binder resin constituting the resin particles is prepared by polymerizing a polymerizable monomer. Examples of the polymerizable monomer used for polymerization include a polymerizable monomer having a carboxyl group and a polymerizable monomer used in combination with the polymerizable monomer having a carboxyl group.

  Specifically, as a polymerizable monomer having a carboxyl group, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, Methacrylic acid ester derivatives such as 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid n -Butyl, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc. Le ester derivatives, acrylonitrile, methacrylonitrile, acrylic acid or methacrylic acid derivatives such as acrylamide.

  Moreover, as a polymerizable monomer used in combination with a polymerizable monomer having a carboxyl group, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3 , 4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene Styrene such as pn-decylstyrene, pn-dodecylstyrene or styrene derivatives, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, vinylidene fluoride, etc. Halogenated vinyls, vinyl propionate, vinyl acetate, vinyl benzoate Vinyl esters such as vinyl methyl ether, vinyl ethyl ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, etc. Examples thereof include vinyl compounds such as N-vinyl compounds, vinyl naphthalene, and vinyl pyridine.

  Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.

  Furthermore, multifunctional such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.

  These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. Examples of the oil-soluble polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carboxyl). Nitriles), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4- t-butylperoxycyclohexyl) propane, tris- Peroxide polymerization initiator or a peroxide such as t- butylperoxy) triazine and the like polymeric initiator having a side chain.

  In the case of using the emulsion association method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.

  In addition, hydrophilic resin is resin which contains an acid monomer (polymerizable monomer) in the component which comprises resin.

  Examples of the acid monomer (polymerizable monomer) include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid. Among these, acrylic acid and methacrylic acid are preferable.

  The ratio of the hydrophilic resin in the toner is preferably 5 to 80% by mass.

  The hydrophobic resin is a resin that does not contain an acid monomer (polymerizable monomer) in the composition component constituting the resin.

(Coloring agent)
As the colorant used in the present invention, a known inorganic or organic colorant can be used. Specific colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the colorant for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  These colorants may be used alone or in combination of two or more as required. The addition amount of the colorant is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the whole toner.

(Chain transfer agent)
In order to adjust the molecular weight of the resin, a commonly used chain transfer agent can be used. The chain transfer agent used is not particularly limited. For example, mercaptans such as n-octyl mercaptan, n-decyl mercaptan, tert-dodecyl mercaptan, and mercaptopropionate esters such as n-octyl-3-mercaptopropionate. , Terpinolene, carbon tetrabromide and α-methylstyrene dimer are used.

(Release agent)
A known compound can be used as the release agent used in the present invention.

  As such, for example, polyolefin wax such as polyethylene wax and polypropylene wax, long chain hydrocarbon wax such as paraffin wax and sazol wax, dialkyl ketone wax such as distearyl ketone, carnauba wax, montan wax, Trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, merit acid tristearyl, distearyl maleate, etc. And amide waxes such as ethylenediamine behenyl amide and trimellitic acid tristearyl amide.

  The amount of the release agent contained in the toner is preferably 1 to 20% by mass and more preferably 3 to 15% by mass with respect to the whole toner.

(Charge control agent)
A charge control agent can be added to the toner according to the present invention as necessary. A known compound can be used as the charge control agent.

(External additive)
Examples of inorganic particles that can be used as an external additive include conventionally known particles. Specifically, silica fine particles, titania fine particles, alumina fine particles, and complex oxides thereof can be preferably used. These inorganic particles are preferably hydrophobic.

  Examples of organic fine particles that can be used as an external additive include spherical fine particles having a number average primary particle size of about 10 to 2000 nm. Examples of the constituent material of the organic fine particles include polystyrene, polymethyl methacrylate, and styrene-methyl methacrylate copolymer.

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

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

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

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

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

<Image formation>
The toner according to the present invention is suitably used for a contact-type fixing type image forming apparatus that fixes a transfer material on which a toner image is formed by passing between heating members constituting the fixing apparatus.

  Hereinafter, the image forming apparatus and the fixing apparatus will be described.

  FIG. 3 is a cross-sectional view showing an example of an image forming apparatus used in the present invention.

  In FIG. 3, 20Y (20M, 20C, 20Bk) is an image forming unit, 21Y (21M, 21C, 21Bk) is a photosensitive drum, 22Y (22M, 22C, 22Bk) is a scorotron charger, and 23Y (23M, 23C, 23Bk). ) Is an exposure optical system, 24Y (24M, 24C, 24Bk) is a developing device, 25Y (25M, 25C, 25Bk) is a cleaning device, 34Y (34M, 34C, 34Bk) is a transfer device, 40 is a fixing device, and 115 is a transfer device. A material conveying belt, 160 is a conveying portion, and P is a transfer material.

  Hereinafter, the image forming apparatus of FIG. 3 will be described.

  In the image forming apparatus of FIG. 3, four sets of image forming units 20 </ b> Y, 20 </ b> M, 20 </ b> C, and 20 </ b> Bk are provided along the transfer material conveyance belt 115.

  Each image forming unit includes a photosensitive drum 21Y (21M, 21C, 21Bk), a scorotron charger 22Y (22M, 22C, 22Bk), an exposure optical system 23Y (23M, 23C, 23Bk), and a developer 24Y (24M, 24C, 24Bk) and a cleaning device (cleaning means) 25Y (25M, 25C, 25Bk), each toner image formed on the photosensitive drum (21Y, 21M, 21C, 21Bk) of each image forming unit is timed. The transfer material (transfer paper, OHP, etc.) P conveyed together is sequentially transferred by a transfer device 34Y (34M, 34C, 34Bk) as transfer means to form a superimposed color toner image.

  The transfer material P is transported on the transfer material transport belt 115, and is a separation member provided in the transport unit 160 at a predetermined interval with a charge eliminating action by a paper separation AC neutralizer 161 as a transfer material separating means. It is separated from the conveyor belt by the claw 210.

  Next, the transfer material P passes through the transport unit 160, and is then transported to a fixing device (fixing unit) 40 including the heating roller 41 and the pressure roller 42, and the heat roller 41 and the pressure roller 42 perform the transfer material P. The transfer material P is sandwiched by the nip portion T to be formed, and heat and pressure are applied to fix the superimposed toner image on the transfer material P, and then discharged outside the apparatus.

  As the image exposure light source, a scanning optical system using a semiconductor laser, a solid state scanner such as an LED or a liquid crystal shutter, and the like can be used as the exposure means.

  The transfer material transport belt 115 for transporting the transfer material is made conductive by adding a conductive filler such as carbon black to a polymer film such as polyimide, polycarbonate, PVdF, or a synthetic rubber such as silicon rubber or fluorine rubber. Are used, and either a drum shape or a belt shape may be used, but a belt shape is preferable from the viewpoint of the degree of freedom in device design.

  The surface of the transfer belt is preferably appropriately roughened. By setting the 10-point surface roughness Rz of the transfer belt to 0.5 to 2 μm, the adhesion between the transfer material and the transfer belt is improved, and the transfer material is prevented from swinging on the transfer belt. Transferability of the toner image to the toner can be improved.

  The transfer material used in the present invention is a support for holding a toner image and is usually called an image support, a transfer body or a transfer paper. Specifically, plain paper from thin paper to thick paper, high-quality paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, OHP plastic film, various transfer materials such as cloth However, it is not limited to these.

  FIG. 4 is a cross-sectional view showing an example of a fixing device (a type using a pressure roller and a heating roller) used in the present invention.

  The fixing device 10 shown in FIG. 4 includes a heating roller 71 and a pressure roller 72 in contact with the heating roller 71. In FIG. 4, reference numeral 17 denotes a toner image formed on a transfer material (transfer paper) P.

  The heating roller 71 has a coating layer 82 made of a fluororesin or an elastic body formed on the surface of the cored bar 81 and includes a heating member 75 made of a linear heater.

  The cored bar 81 is made of metal and has an inner diameter of 10 to 70 mm. Although it does not specifically limit as a metal which comprises the metal core 81, For example, metals, such as iron, aluminum, copper, or these alloys can be mentioned.

  The thickness of the cored bar 81 is 0.1 to 15 mm, and is determined in consideration of a balance between a request for energy saving (thinning) and strength (depending on the constituent materials). For example, in order to maintain the same strength as that of a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the wall thickness needs to be 0.8 mm.

  Examples of the fluororesin constituting the surface of the coating layer 82 include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).

  The thickness of the coating layer 82 made of a fluororesin is 10 to 500 μm, preferably 20 to 400 μm.

  When the thickness of the coating layer 82 made of the fluororesin is less than 10 μm, the function as the coating layer cannot be sufficiently exhibited, and the durability as the fixing device cannot be ensured. On the other hand, there is a problem that the surface of the coating layer exceeding 500 μm is easily scratched by paper dust, and toner or the like adheres to the scratched part, thereby causing image smearing.

  Further, as the elastic body constituting the covering layer 82, it is preferable to use silicon rubber, silicon sponge rubber or the like having good heat resistance such as LTV, RTV, HTV.

  The Asker C hardness of the elastic body constituting the covering layer 82 is less than 80 °, preferably less than 60 °.

  The thickness of the coating layer 82 made of an elastic body is preferably 0.1 to 30 mm, and more preferably 0.1 to 20 mm.

  As the heating member 75, a halogen heater can be preferably used.

  The pressure roller 72 is formed by forming a coating layer 84 made of an elastic body on the surface of the cored bar 83. The elastic body constituting the coating layer 84 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubber. The silicon rubber exemplified as the one constituting the coating layer 84 and It is preferable to use silicon sponge rubber.

  Moreover, 0.1-30 mm is preferable and, as for the thickness of the coating layer 84, 0.1-20 mm is more preferable.

  The heating roller may be used by applying 0.3 mg or less of silicon oil per print, or may be used without oil.

  FIG. 5 is a schematic view showing an example of a fixing device (a type using a belt and a heating roller) used in the present invention.

  The fixing device 10 in FIG. 5 is of a type using a belt and a heating roller in order to secure a nip width, and the pressure pressed against the fixing roller 601 through the fixing roller 601 and the seamless belt 11 and the seamless belt 11. The pad (pressure member) 12a, the pressure pad (pressure member) 12b, and the lubricant supply member 40 constitute a main part.

  The fixing roller 601 is formed by forming a heat-resistant elastic layer 10b and a release layer (heat-resistant resin layer) 10c around a metal core (cylindrical core) 10a. A halogen lamp 14 is disposed as a heating source. The temperature of the surface of the fixing roller 601 is measured by the temperature sensor 15, and the halogen lamp 14 is feedback controlled by a temperature controller (not shown) based on the measurement signal so that the surface of the fixing roller 601 is adjusted to a constant temperature. The seamless belt 11 contacts the fixing roller 601 so as to be wound at a predetermined angle, thereby forming a nip portion.

  Inside the seamless belt 11, a pressure pad 12 having a low friction layer on the surface is disposed in a state of being pressed against the fixing roller 601 via the seamless belt 11. The pressure pad 12 is provided with a pressure pad 12a to which a strong nip pressure is applied and a pressure pad 12b to which a weak nip pressure is applied, and is held by a holder 12c made of metal or the like.

  Further, a belt traveling guide is attached to the holder 12c so that the seamless belt 11 can smoothly slide and rotate. The belt running guide is preferably a member having a low coefficient of friction because it rubs against the inner surface of the seamless belt 11, and a member having low thermal conductivity is preferred so that heat is not easily taken from the seamless belt 11.

<Transfer material>
The transfer material used in the present invention is a support for holding a toner image, and is usually called an image support, a recording material, or transfer paper. Specifically, various transfer materials such as plain paper and fine paper from thin paper to thick paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, plastic film for OHP, cloth, etc. However, it is not limited to these.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Production of toner>
(Preparation of resin particles A) Preparation of three-layer resin particles First-stage polymerization (polymerization of hydrophilic resin)
Into a reaction vessel equipped with a stirrer, temperature sensor, cooling tube, and nitrogen introduction device, 8 g of sodium dodecyl sulfate and 3000 g of ion-exchanged water were charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. Allowed to warm. After heating, 10 g of potassium persulfate dissolved in 200 g of ion-exchanged water was added, the liquid temperature was again 80 ° C., the following monomer mixture was added dropwise over 1 hour, and then heated at 80 ° C. for 2 hours. Polymerization was carried out by stirring to prepare resin particles. This is designated as “resin particles (1A)”.

Styrene 532.0g
n-Butyl acrylate 196.0g
Methacrylic acid 76.0g
n-octyl mercaptan 16.0 g
Second stage polymerization (polymerization of hydrophobic resin)
A reaction vessel equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introducing device was charged with a solution prepared by dissolving 7 g of polyoxyethylene (2) sodium dodecyl ether sulfate in 800 g of ion-exchanged water, heated to 98 ° C., 260 g of resin particles (1A) and a solution prepared by dissolving the following monomer solution at 90 ° C. were added, and the mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path was added. A dispersion liquid containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour.

246.0 g of styrene
n-Butyl acrylate 119.0g
n-Octyl mercaptan 1.5g
Polyethylene wax (melting point 80 ° C) 190.0g
Next, an initiator solution in which 6 g of potassium persulfate is dissolved in 200 g of ion-exchanged water is added to this dispersion, and the system is heated and stirred at 82 ° C. for 1 hour to obtain resin particles. It was. This is designated as “resin particles (2A)”.

Third stage polymerization (polymerization of hydrophilic resin)
Furthermore, a solution prepared by dissolving 11 g of potassium persulfate in 400 g of ion-exchanged water was added to the solution of “resin particles (2A)”, and the temperature was set to 82 ° C.
414.0 g of styrene
n-Butyl acrylate 180.0g
Methacrylic acid 6.0g
n-octyl mercaptan 1.0 g
A monomer mixture consisting of was added dropwise over 1 hour. After completion of the dropping, polymerization was carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to obtain resin particles. This is designated as “resin particle A”. The “resin particle A” had a glass transition temperature of 37 ° C. and a weight average molecular weight of 22,000.

(Preparation of Resin Particle B) Resin Particles Only of Hydrophilic Resin “Resin Particle B” was prepared in the same manner except that the monomer mixed solution in the second stage polymerization of the “resin particle A” was changed to the following. The “resin particle B” had a glass transition temperature of 44 ° C. and a weight average molecular weight of 25,000.

Styrene 241.0g
n-Butyl acrylate 88.0g
Methacrylic acid 33.0 g
n-Octyl mercaptan 1.5g
Polyethylene wax (melting point 89d ° C) 190.0g
(Preparation of Resin Particle C) Preparation of Resin Particles for Shell Layer 8 g of sodium dodecyl sulfate and 3000 g of ion-exchanged water were charged in a reaction vessel equipped with a stirrer, temperature sensor, cooling tube, and nitrogen introducing device, and the nitrogen gas flow was 230 rpm. The internal temperature was raised to 80 ° C. while stirring at a stirring speed. After heating, 10 g of potassium persulfate dissolved in 200 g of ion-exchanged water was added, the liquid temperature was again 80 ° C., the following monomer mixture was added dropwise over 1 hour, and then heated at 80 ° C. for 2 hours. Polymerization was carried out by stirring to prepare resin particles. This is designated as “resin particle C”. The “resin particle C” had a glass transition temperature of 50 ° C. and a molecular weight weight average molecular weight of 15,000.

Styrene 564.0g
n-Butyl acrylate 193.0g
Methacrylic acid 48.0g
n-octyl mercaptan 16.0 g
(Preparation of Resin Particle D) Preparation of Resin Particles for Shell Layer In the preparation of “resin particle C”, “resin particle D” was prepared in the same manner except that the amount of n-octyl mercaptan as a chain transfer agent was changed to 5 g. Produced. The “resin particles D” had a glass transition temperature of 50 ° C. and a molecular weight weight average molecular weight of 42,000.

<Preparation of colorant dispersion>
90 g of sodium dodecyl sulfate was dissolved in 1600 g of ion-exchanged water with stirring. While stirring this solution, 420 g of carbon black “Regal 330R” (manufactured by Cabot Corp.) is gradually added, and then dispersed by using a stirrer “Claremix” (manufactured by M Technique Co., Ltd.). A dispersion of agent particles was prepared. This is referred to as a “colorant dispersion”. The particle diameter of the colorant particles in this colorant dispersion was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and found to be 110 nm.

<Preparation of alkaline solution>
A 25% aqueous sodium hydroxide solution prepared by stirring and dissolving 333 g of sodium hydroxide in 1000 g of ion-exchanged water was prepared as an “alkali solution”.

<Preparation of Toner Base Bk1>
(Aggregation process)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, 300 g of “resin particles A”, 1400 g of ion-exchanged water, 120 g of “colorant dispersion”, polyoxyethylene (2) A solution prepared by dissolving 3 g of sodium dodecyl ether sulfate in 120 g of ion-exchanged water was added and the liquid temperature was adjusted to 30 ° C., and then the pH was adjusted to 10 by adding a 5N aqueous sodium hydroxide solution. Next, an aqueous solution in which 35 g of magnesium chloride was dissolved in 35 g of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After holding for 3 minutes, the temperature was raised and the system was heated to 90 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 90 ° C.

In this state, when the particle diameter of the colored particles was measured by "Coulter Multisizer III" (manufactured by Beckman Coulter, Inc.), median particle size (D ₅₀₎ in volumetric basis becomes 6.0 .mu.m, sodium chloride An aqueous solution in which 150 g was dissolved in 600 g of ion-exchanged water was added to stop particle growth.

(Aging process)
Next, a pH meter was installed in the dispersion liquid of the colored particles obtained in the aggregation step, and the measured pH was 6.0. Therefore, the above “alkali solution” was added, and the pH of the dispersion liquid was adjusted to 8.0. It was adjusted.
The temperature of the dispersion was kept at 90 ° C., and the mixture was heated and stirred until the circularity became 0.965, and the surface of the colored particles was alkali-treated to prepare a dispersion of “toner base 1”.

  Thereafter, the liquid temperature was cooled to 30 ° C. over 30 minutes, and stirring was stopped.

(Washing and drying process)
The colored particles prepared in the aging step were solid-liquid separated with a basket type centrifuge “MARK III Model No. 60 × 40” (manufactured by Matsumoto Kikai Co., Ltd.) to form a toner base (colored particles) wet cake. The wet cake was washed with water using the basket-type centrifuge until the electric conductivity of the filtrate reached 5 μS / cm, and then transferred to a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). % To dryness to produce “toner base Bk1”.

<Production of toner bases Bk2 to Bk13>
“Toner bases Bk2 to Bk13” were prepared in the same manner except that the flocculant in the aggregation step of “toner base Bk1” and the pH and temperature of the aging step were changed.

  Table 1 shows the production conditions of “toner base materials Bk1 to Bk15”.

<Production of toner bases Bk14 and Bk15>
After the aggregation step of “Preparation of toner base Bk1”, aging was performed at 90 ° C. for 60 minutes in order to adjust the circularity of the aggregated particles. Thereafter, 530 g of “resin particles C or D” for the shell layer was added, and heating and stirring were continued for 4 hours to fuse the resin particles for shells onto the surface of the core aggregated particles. Here, after 17 g of sodium chloride was added to stop the particle growth, aging was carried out at 97 ° C. until the desired circularity was reached in order to fuse the latex for the shell. After completion of aging, the mixture was cooled to 30 ° C. over 30 minutes, sodium hydroxide was added to adjust the pH to 10, and stirring was stopped. The produced core / shell particles were processed in the same manner as the washing and drying steps in the production of the toner base Bk1, thereby producing “toner bases Bk14 and Bk15”.

  Table 2 shows the production conditions of “toner base materials Bk14 and Bk15”.

(Preparation of colored particles C1 to C15)
“Colored particles C1 to C15” were similarly used except that 20 g of “Legal 330R” (manufactured by Cabot) used in the production of “colored particles Bk1 to Bk15” was changed to 10 g of “CI Pigment Blue 15: 3”. Was made.

(Preparation of colored particles M1 to M15)
“Colored particles M1 to M15” were prepared in the same manner except that 20 g of “Regal 330R” (manufactured by Cabot) used in the production of “colored particles Bk1 to Bk15” was changed to 17 g of “CI Pigment Red 122”. did.

(Preparation of colored particles Y1 to Y15)
“Colored particles Y1 to Y15” were prepared in the same manner except that 20 g of “Legal 330R” (manufactured by Cabot) used in the production of “colored particles Bk1 to Bk15” was changed to 18 g of “CI Pigment Yellow 74”. did.

(External additive treatment of colored particles)
Next, 1% by mass of hydrophobic silica (number average primary particle size = 12 nm, hydrophobization degree = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, hydrophobization degree) are prepared on each colored particle prepared above. = 63) was added in an amount of 1% by mass and mixed using a “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.). Thereafter, coarse particles are removed using a sieve having an opening of 45 μm to obtain “toner Bk1 to Bk15”, “toner C1 to C15”, “toner M1 to M15”, and “toner Y1 to Y15”.

<Preparation of developer>
Each of the toners prepared above is mixed with a ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin so that the toner concentration becomes 6% by mass, and “Developers Bk1 to Bk15” and “Developer” are mixed. “Developers C1 to C15”, “Developers M1 to M15”, and “Developers Y1 to Y15”.

<Evaluation>
The following items were evaluated for the toner prepared above. A developer corresponding to each toner was used. In the evaluation, “A” and “B” indicate that there was no problem and “x” indicates that there was a problem, and “B” indicates that there was a problem.

(Visual evaluation)
<Storage stability>
2 g of each of the toners prepared above was placed in a sample tube, shaken 500 times with a tapping denser, and allowed to stand in an environment of 55 ° C. and 35% RH for 2 hours. Next, it is put in a 48 mesh sieve, sieved under a constant vibration condition, and the ratio (mass%) of the amount of toner remaining on the mesh is measured, and this is used as the toner aggregation rate. did.

A: The toner aggregation rate is less than 15% by mass (very good storage stability)
A: The toner aggregation rate is 15 to 45% by mass (good storage stability)
X: The toner aggregation rate exceeds 45% by mass (needs cold transport).

(Image evaluation)
As the image evaluation apparatus, the image forming apparatus shown in FIG. 2 was used with the fixing device shown in FIG. The fixing speed and the surface material of the heat roll were as follows.

Fixing speed: 280mm / sec (about 50 sheets / A4 size, landscape feed)
Heat roll surface material: PTFE
The evaluation was carried out for the following evaluation items in an environment of 20 ° C. and 55% RH by sequentially loading the toner prepared above in the evaluation apparatus.

The print is an image with a pixel rate of 10% (original image with 7% character image, human face photo, solid white image, solid black image divided into 1/4 each), A4 quality fine paper (64g / m ² ) 1 million copies were made.

<Image density>
The image density was evaluated by the density of the print image in the solid black image portion. The image density was measured using “RD-918” (manufactured by Macbeth Co.), and the relative reflection density with the paper reflection density set to “0”.

Evaluation Criteria ◎: Good at 1.4 or higher both after initial printing and after 100,000 sheets printing ○: 1.4 or higher at initial stage and 1.2 or higher after printing 100,000 sheets No problem for practical use ×: Initial and 10 Both levels after printing 10,000 sheets are less than 1.2, which is a practical problem.

<Fixable temperature (mending tape peeling method)>
The fixable temperature was evaluated by changing the surface temperature of the seamless belt 11 from 90 to 150 ° C. in increments of 5 ° C. in an environment of normal temperature and normal humidity (20 ° C., 50% RH) to create a fixed image.

  Specifically, the fixing strength of each of the obtained fixed images was measured by a mending tape peeling method, and the fixing temperature at which a fixing rate of 90% or more was obtained was evaluated as the fixing possible temperature.

  Hereinafter, the mending tape peeling method will be described.

1) Measure absolute reflection density D ₀ of solid black 2) Lightly affix “Mending tape” (manufactured by Sumitomo 3M: No.810-3-12) to a solid black image 3) Tape at a pressure of 1 kPa 4) Peel off the tape with an angle of 180 ° C. and a force of 200 g 5) Measure the absolute reflection density D ₁ after peeling 6) Calculate the fixing rate. Fixing rate (%) = D ₁ / D ₀ × 100
For the measurement of the image density, a reflection densitometer “RD-918” (manufactured by Macbeth) was used.

  Table 3 shows the evaluation results.

  As is clear from the evaluation results, “Examples 1 to 10” are excellent in all evaluation items, but “Comparative Examples 1 to 5” have some problems in the evaluation items.

FIG. 6 is a schematic diagram illustrating an example of a process in which toner is formed. FIG. 10 is a schematic diagram illustrating an example of a process in which a toner having a conventional core / shell structure is formed as a comparative example. It is sectional drawing which shows an example of the image forming apparatus used for this invention. It is sectional drawing which shows an example of the fixing device (The type using a pressure roller and a heating roller) used for this invention. FIG. 2 is a schematic diagram illustrating an example of a fixing device (a type using a belt and a heating roller) used in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Toner base 11 Resin particle 12 Colorant particle 13 Colored particle 21 Core part 22 Layer having a crosslinked structure 23 Shell layer

Claims (3)

An aggregation step of aggregating a plurality of resin particles having anions to adjust the particle size to form aggregated particles;
In the method for producing a toner for developing an electrostatic image having a ripening step of adjusting the circularity of the aggregated particles,
In the aging step, under conditions where polyvalent metal ions are present in the medium,
A method for producing a toner for developing an electrostatic charge image, comprising heating and stirring in an alkaline solution having a pH of 8 to 14. An agglomeration step of aggregating a plurality of resin particles having a hydrophilic resin and a hydrophobic resin to adjust the particle diameter;
In the method for producing a toner for developing an electrostatic image having a ripening step of adjusting the circularity of the aggregated particles,
In the aging step, under conditions where polyvalent metal ions are present in the medium,
A method for producing a toner for developing an electrostatic charge image, comprising heating and stirring in an alkaline solution having a pH of 8 to 14. A toner for developing electrostatic images obtained by aggregating a plurality of resin particles having anions, wherein a high molecular weight layer is formed on the surface of the toner for developing electrostatic images by an ion crosslinking reaction. Toner for developing electrostatic image.

Images