JP2008089913A - Toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner containing ample amount of colorant and being superior in the ease of fixing to a recording medium at a low-temperature range (low-temperature fixability), durability and storage stability (thermal and storage stability and long-term storage stability). <P>SOLUTION: The toner includes a large number toner particles, wherein each of the toner particles has a core region and a shell area coating the periphery of the core region and having a composition different from that of the core region. The core region and the shell region each consist of materials containing the colorant and a resin, and a concentration C<SB>C</SB>[wt.%] of the colorant in the core region and the concentration C<SB>S</SB>[wt.%] of the colorant in the shell region satisfy the relation C<SB>C</SB>≤C<SB>S</SB>. The concentration range C<SB>C</SB>of the colorant in the core region is, preferably, 1.8-6.5 wt.%, and the concentration C<SB>S</SB>of the colorant in the shell region is, preferably, 6.0-22.0 wt.%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner.

  A number of methods are known as electrophotographic methods. In general, a process (exposure process) of forming an electrical latent image on a photoconductor by various means using a photoconductive substance, A development step of developing the latent image with toner, a transfer step of transferring the toner image onto a transfer material (recording medium) such as paper, and a fixing step of fixing the toner image by heating using a fixing roller, etc. have.

The toner used in the electrophotographic method as described above is generally composed of a material containing a resin as a main component (hereinafter also simply referred to as “resin”) and a colorant.
In a toner used in electrophotography, it is required to contain a sufficient colorant in order to obtain an image having a sufficient density, particularly in order to obtain an image having a sufficient density while suppressing the amount of toner used. ing.

  In general, it is advantageous to use a resin having a low glass transition temperature as a resin constituting the toner in order to save energy and form a fixed image of toner at high speed (high speed printing). However, when the resin constituting the toner has a low glass transition temperature, there are problems such that the durability and storage stability (storage stability) of the toner particles are lowered, and offset in a high temperature range is likely to occur. there were.

In order to solve such a problem, there is an attempt to use a combination of plural kinds of resins. In such a case, a resin having a low glass transition temperature and a resin having a high glass transition temperature are usually used in combination (for example, see Patent Document 1).
However, in the conventional toner, when a plurality of types of resins are used as the constituent material of the toner, it is difficult to sufficiently exhibit the characteristics of the plurality of resins constituting the toner. That is, the properties of the plurality of types of resins constituting the toner are averaged, and it is difficult to achieve excellent durability and storage stability as well as low-temperature fixability.

JP 2003-122051 (paragraph numbers 0105, 0111, 0130, etc.)

  An object of the present invention is to provide a toner containing a sufficient amount of a colorant and having excellent ease of fixing to a recording medium in a low temperature region (low temperature fixability), durability and storage stability. It is in.

Such an object is achieved by the present invention described below.
The toner of the present invention is a toner containing a large number of toner particles,
The toner particles have a core region and a shell region that covers an outer periphery of the core region and has a composition different from that of the core region.
The core region and the shell region are each composed of a material containing a resin and a colorant,
When the concentration of the colorant in the core region is C _C [wt%] and the concentration of the colorant in the shell region is C _S [wt%], the relationship C _C ≦ C _S is satisfied. Toner.
As a result, it contains a sufficient amount of colorant and is easy to fix to a recording medium in a low temperature range (low temperature fixability), durability, and preservability (heat resistant preservability, long term preservability, etc.). An excellent toner can be provided.

The toner of the present invention, the concentration _{C C} of the colorant in the core region is preferably a 1.8~6.5wt%.
As a result, the color development property (color density) of the toner can be made sufficiently high, and the low-temperature fixability of the toner can be made particularly excellent.
The toner of the present invention, the concentration _{C S} of the colorant in the shell region is preferably a 6.0~22.0wt%.
Thereby, the strength and shape stability of the toner particles can be made particularly excellent, and the durability and storage stability of the toner can be made particularly excellent. Further, the color developability (color density) of the toner can be made particularly excellent.

In the toner of the present invention, the concentration C _C [wt%] of the colorant in the core region and the concentration C _S [wt%] of the colorant in the shell region are 0.08 ≦ C _C / It is preferable to satisfy the relationship of C _S ≦ 0.78.
As a result, the durability, storage stability (heat resistant storage stability, long-term storage stability, etc.), and color developability (coloring density) can be made particularly excellent while the low-temperature fixability of the toner is sufficiently excellent.

In the toner of the present invention, it is preferable that the colorant contained in the core region and the colorant contained in the shell region have different compositions.
As a result, a toner having a desired color tone (a color tone that is difficult to express with a single colorant) while having excellent low-temperature fixability, durability, and storage stability (heat resistant storage stability, long-term storage stability, etc.) Can be provided.

In the toner of the present invention, it is preferable that the colorant contained in the core region and the colorant contained in the shell region have different average particle sizes.
As a result, the toner can be made particularly excellent in low-temperature fixability, durability, and storability (heat-resistant storability, long-term storability, etc.).
In the toner of the present invention, the average thickness of the shell region is preferably 80 to 1000 nm.
Thereby, the color development property (color density) of the toner, the durability of the toner particles, the storage property (heat resistant storage property, long-term storage property, etc.) and the like can be made particularly excellent.

In the toner of the present invention, when the average thickness of the shell region is L [nm] and the average particle diameter of the colorant contained in the shell region is d ₂ [nm], 0.03 ≦ d ₂ / L It is preferable to satisfy the relationship of ≦ 0.25.
Thereby, the color development property (color density) of the toner, the durability of the toner particles, the storage property (heat resistant storage property, long-term storage property, etc.) and the like can be made particularly excellent.
In the toner of the present invention, the toner particles preferably have an average particle size of 3.0 to 10.0 μm.
As a result, the durability, storage stability, and color developability (color density) can be made particularly excellent while the low-temperature fixability of the toner is sufficiently excellent. Further, it can be suitably applied to high-resolution image formation.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of toner particles constituting the toner of the present invention.
<Toner>
First, the toner of the present invention will be described.
The toner is composed of a large number of toner particles 1.

<Toner particle structure>
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of toner particles constituting the toner of the present invention.
The toner particle 1 has a core region (core portion, core) 11 and a shell region (outer shell) 12 that covers the outer periphery of the core region 11. The core region 11 and the shell region 12 are both made of a material containing a resin and a colorant. The concentration of the colorant in the core region 11 is equal to or less than the concentration of the colorant in the shell region 12. That is, when the colorant concentration in the core region 11 is C _C [wt%] and the colorant concentration in the shell region 12 is C _S [wt%], the relationship C _C ≦ C _S is satisfied. By satisfying these relationships, the durability and storability (heat-resistant storability, long-term storability) of the toner are improved while improving the ease of fixing to a recording medium (low-temperature fixability) in a low-temperature region. Etc.) can be made excellent. In addition, the content of the colorant in the toner particles can be increased by including the colorant in the shell region as well as in the core region. As a result, the amount of toner required to form an image having a predetermined density (color density) can be reduced, which is advantageous from the viewpoint of cost reduction and resource saving required for image formation.

On the other hand, when the above relationship is not satisfied, the excellent effect as described above cannot be obtained.
For example, when the content of the colorant in the core region is higher than the content of the colorant in the shell region (the core region contains the colorant and the shell region does not contain the colorant. In some cases, the hardness and strength of the shell region are reduced, the stability of the shape of the toner particles is lowered, and aggregation between the toner particles is likely to occur. As a result, the durability and storage stability (heat resistant storage stability, long-term storage stability, etc.) of the toner as a whole are insufficient. Further, it becomes difficult to increase the colorant content in the toner particles, and the amount of toner required to form an image having a predetermined density increases. As a result, the cost required for image formation increases and it is not preferable from the viewpoint of resource saving. In addition, it is conceivable to maintain the colorant content in the entire toner particles by increasing the colorant content in the core region. Even if a resin having a low temperature is used, the low-temperature fixability of the toner is hindered. That is, the low temperature fixability of the toner cannot be made excellent. In particular, when the core region contains a colorant and the shell region does not contain a colorant, the above-described problem occurs more remarkably.
On the other hand, when the shell region contains a colorant and the core region does not contain a colorant, it is difficult to sufficiently increase the content of the colorant in the toner particles. If the content of the colorant in the toner particles is insufficient, the amount of toner required to form an image having a predetermined density increases. As a result, the cost required for image formation increases and it is not preferable from the viewpoint of resource saving. Further, when the colorant content in the toner particles is particularly low, there is a possibility that an image having a desired density cannot be formed. In addition, it is conceivable to maintain the content of the colorant in the entire toner particle by increasing the thickness of the shell region. In such a case, the ratio (volume ratio) of the core region in the entire toner particle is relatively low. Thus, the fixability (particularly low-temperature fixability) and the fixing strength to the recording medium cannot be maintained.
Hereinafter, the core region 11 and the shell region 12 will be described in detail.

[Core area]
The core region 11 is made of a material containing a resin and a colorant. Thereby, it is possible to make the fixing favorable area as a whole toner particularly wide.
(resin)
The resin constituting the core region 11 is not particularly limited, but is preferably a polyester resin. Polyester resins are advantageous in improving ease of fixing in a low temperature region (low temperature fixing property), and are advantageous in forming a high gloss image with high transparency.
Moreover, it is preferable that the core area | region 11 is comprised by the polyester A as described below among polyester-type resin.

[Polyester A]
Polyester A may be composed of a single resin component or may be composed of two or more resin components.
The glass transition temperature Tg (A) of the polyester A is not particularly limited, but is preferably 30 to 55 ° C, and more preferably 35 to 50 ° C. When the glass transition temperature Tg (A) of the polyester A is within the above range, the toner particles 1 are sufficiently excellent in durability and storage stability (heat resistant storage stability, long-term storage stability, etc.) In particular, the ease of fixability (low temperature fixability) can be made excellent.

The softening temperature T1 / 2 (A) of polyester A is not particularly limited, but is preferably 60 to 150 ° C, more preferably 80 to 120 ° C. Thereby, the occurrence of offset in the high temperature region can be more effectively prevented while making the low temperature fixability particularly excellent. In the present specification, the softening temperature T1 / 2 is a value obtained as follows using a flow tester (CFT-500, manufactured by Shimadzu Corporation) which is a constant load extrusion type capillary rheometer. Point to. That is, as shown in FIG. 2A, a sample 8 (weight 1.5 g) is filled into a cylinder 7 having a nozzle 6 having a nozzle diameter D of 1.0 mm and a nozzle length (depth) L of 1.0 mm. When a load of 10 kg per unit area (cm ² ) is applied from the side opposite to the nozzle 6 and heated at a temperature rising rate of 6 ° C. per minute in that state, the stroke S of the load surface 9 (of the load surface 9 By measuring the sinking value), the relationship between the elevated temperature and the stroke S is obtained as shown in FIG. 2 (b). The outflow of the sample 8 from the nozzle 6 starts and the stroke S increases rapidly. When the temperature when the curve rises is Tfb [° C.], and when the temperature when the flow of the sample 8 from the nozzle 6 almost ends and the curve is bent is Tend [° C.], the stroke at Tfb Stroke S at Sfb and Tend The temperature at the intermediate value become S1 / 2 with nd, herein it employs as a softening temperature T1 / 2.

Moreover, although the weight average molecular weight Mw (A) of polyester A is not specifically limited, It is preferable that it is 1000-1800, and it is more preferable that it is 2000-150,000. Thereby, the occurrence of offset in the high temperature region can be more effectively prevented, and the amount of volatile organic compounds can be particularly reduced.
The acid value AV (A) of the polyester A is not particularly limited, but is preferably 1.0 to 30.0 KOH mg / g, and more preferably 3.0 to 20.0 KOH mg / g. When the acid value AV (A) of the polyester A is a value within the above range, the toner storage stability can be sufficiently improved, and the fixing strength of the toner to the recording medium can be particularly excellent. .

It is preferable that the polyester A has a composition different from a resin (particularly, polyester B) constituting the shell region 12 described later. As a result, for example, the low temperature fixability of the toner is particularly excellent, and the storage stability (heat resistant storage stability, long-term storage stability, etc.) and durability of the toner can be particularly excellent.
Polyester resins generally have a configuration in which a polybasic acid component and a polyhydric alcohol component are dehydrated and condensed.

  Examples of the polybasic acid component constituting the polyester A include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid; maleic anhydride, fumaric acid, Aliphatic carboxylic acids such as succinic acid, alkenyl succinic anhydride, and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and the like can be used, and one or more selected from these can be used in combination. . Of these polybasic acids, aromatic carboxylic acids are preferably used.

  Examples of the polyhydric alcohol component constituting the polyester A include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, trimethylolpropane, and pentaerythritol. Alicyclic diols such as cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A; aromatic diols such as ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc. These can be used alone or in combination. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.

In addition, polyester A may contain structural components (structural raw material) other than a polybasic acid component and a polyhydric alcohol component. For example, polyester A may contain a monocarboxylic acid and / or a monoalcohol as a constituent component (constituent monomer). Thereby, for example, the acid value of polyester A can be suitably adjusted. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride, and the like. Examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, trifluoroethanol, trichloroethanol, hexafluoroisopropanol, phenol and the like, and one or more selected from these are used. Can be used in combination.
Polyester A contains a polybasic acid component having three or more carboxyl groups in one molecule and / or a polyhydric alcohol component having three or more hydroxyl groups in one molecule as a constituent component. There may be.

  Polyester A may contain a polyvalent epoxy compound as a constituent component. Thereby, polyester A can have a suitable crosslinked structure. Examples of the polyvalent epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, ethylene glycol diglycidyl ether, hydroquinone diglycidyl ether, N, N-diglycidyl aniline, glycerin triglycidyl ether. , Trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetrakis 1,1,2,2 (p-hydroxyphenyl) ethane tetraglycidyl ether, cresol novolac type epoxy resin, phenol novolac type epoxy Resin, polymer of vinyl compound having epoxy group (including copolymer), epoxidized resorcinol-acetone condensate, partial Epoxidized polybutadiene, semi-drying or drying fatty acid ester epoxy compound and the like may be used alone or in combination of two or more selected from these. Among them, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether Pentaerythritol tetraglycidyl ether is preferred.

  Specific examples of the bisphenol A type epoxy resin include, for example, Epicron 850, Epicron 1050, Epicron 2055, Epicron 3050 and the like manufactured by Dainippon Ink and Chemicals, Inc. Specific examples of the bisphenol F type epoxy resin include, for example, Examples include Epicron 830 and Epicron 520 manufactured by Dainippon Ink & Chemicals, Inc. Specific examples of the cresol novolak epoxy resin include, for example, Epicron N-660, Epicron N-665 and Epicron manufactured by Dainippon Ink and Chemicals, Inc. N-667, Epicron N-670, Epicron N-673, Epicron N-680, Epicron N-690, Epicron N-695 and the like. Specific examples of phenol novolac type epoxy resins include, for example, Dainippon Ink Chemical Epi made by industry Ron N-740, EPICLON N-770, EPICLON N-775, include EPICLON N-865 or the like. Moreover, as a polymer of the vinyl compound which has an epoxy group, the homopolymer of a glycidyl (meth) acrylate, an acrylic copolymer, a copolymer with styrene, etc. are mentioned, for example.

  Polyester A may contain a monoepoxy compound as a constituent component. Thereby, fixing property and offset resistance at high temperature can be made particularly excellent. Examples of the monoepoxy compound include phenyl glycidyl ether, alkylphenyl glycidyl ether, alkyl glycidyl ether, phenyl glycidyl ester, glycidyl ether of alkylphenol alkylene oxide adduct, α-olefin oxide, monoepoxy fatty acid alkyl ester, and the like. One or two or more selected from can be used in combination. Of these, alkyl glycidyl esters are preferred. Specific examples of the alkyl glycidyl ester include neodecanoic acid glycidyl ester (manufactured by Shell Japan, Cardura E).

  Polyester A can be produced by a condensation reaction using components such as the above-mentioned polyhydric alcohol component and polybasic acid component. For example, the above components are mixed in a reaction vessel equipped with a thermometer, a stirrer, and a flow-down condenser, heated at 150 to 250 ° C. in the presence of an inert gas such as nitrogen, and then further under a reduced pressure atmosphere. The reaction is allowed to proceed, and when the predetermined physical property value is reached, the reaction is stopped and cooled, whereby the desired reactant (polyester A) can be obtained. As described above, by performing the reaction under a reduced pressure atmosphere, it is effective to continuously remove the low-molecular compounds produced as a by-product from the reaction system and to leave unreacted raw materials in the polyester A as a product. Can be prevented. Thereby, the amount of volatile organic compounds (VOC) as the polyester A can be suppressed.

  Polyester A may be synthesized using, for example, a catalyst. Examples of the catalyst (esterification catalyst) include organic metals such as dibutyltin dilaurate and dibutyltin oxide; metal alkoxides such as tetrabutyl titanate and the like. Further, when the carboxylic acid component to be used is a lower alkyl ester, a transesterification catalyst can be used. Examples of the transesterification catalyst include metal acetates such as zinc acetate, lead acetate, and magnesium acetate; metal oxides such as zinc oxide and antimony oxide; metal alkoxides such as tetrabutyl titanate. About the addition amount of a catalyst, it is preferable to set it as the range of 0.01-1 wt% with respect to the total amount of a raw material.

The core region 11 preferably contains a linear polyester resin as the polyester A. As a result, the offset in the high temperature region is surely prevented, the durability and storage stability (heat resistant storage property, long-term storage property, etc.) of the toner particles 1 are sufficiently excellent, and the fixing property in the low temperature region is reduced. The ease (low temperature fixability) can be made particularly excellent.
In particular, the core region 11 preferably contains, as the polyester A, a linear polyester resin and a cross-linked polyester resin. As a result, offset in the high temperature region can be prevented more reliably, and the durability and storage stability (heat resistant storage property, long-term storage property, etc.) of the toner particles 1 can be improved, and the fixing property in the low temperature region is easy. The thickness (low-temperature fixability) can be made particularly excellent.

(Coloring agent)
As the colorant constituting the core region 11, for example, a pigment, a dye, or the like can be used. Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, chrome lead, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S. , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth 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, fast violet B, methyl violet lake, bitumen, cobalt blue, al Reblue Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide, and magnetic materials containing magnetic metals such as Fe, Co, and Ni. Further, the colorant constituting the core region 11 may be substantially composed of a single substance (pure substance), or may be a mixture of plural kinds of substances.

As described above, the colorant concentration C _C [wt%] in the core region 11 has a relationship of C _C ≦ C _{S with} the colorant concentration C _S [wt%] in the shell region 12. In particular, it is preferable that the following conditions are satisfied.
That is, the concentration _{C C} of the colorant in the core region 11 is preferably in the range of 1.8～6.5Wt%, and more preferably 2.3~5.2wt%. When the concentration C _C of the colorant in the core region 11 is within this range, while the toner color development property (color density) is sufficiently high, that with particularly excellent low-temperature fixability of the toner Can do.

  In addition, the average particle size of the colorant (first colorant) contained in the core region 11 is preferably 10 to 100 nm, and more preferably 20 to 80 nm. As a result, the color development property of the toner can be made sufficiently excellent, and the low-temperature fixability of the toner can be made particularly excellent. In the present specification, the average particle diameter means a volume-based average particle diameter unless otherwise specified.

(Other ingredients)
The core region 11 may contain components other than those described above. Examples of such components include resins other than polyester A, waxes, charge control agents, magnetic powders, and the like.
Examples of the resin include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene- Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid ester copolymer, styrene-α-chloro A homopolymer or copolymer containing styrene or a styrene substitution product in a styrene resin such as a methyl acrylate copolymer, a styrene-acrylonitrile-acrylic acid ester copolymer, a styrene-vinyl methyl ether copolymer, an epoxy resin, Urethane-modified epoxy resin, silicon Modified epoxy resin, vinyl chloride resin, rosin modified maleic acid resin, phenyl resin, polyethylene resin, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral Examples thereof include resins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins.

  Examples of the wax include hydrocarbon waxes such as ozokerite, cercin, paraffin wax, microwax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, methyl palmitate , Methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, fatty acid ester, polyglycerin fatty acid ester and other ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, Olefinic wax such as oxidized polypropylene wax, 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide Amide wax, laurone, ketone waxes such as stearone, ether waxes, and the like, can be used singly or in combination of two or more of them.

Examples of the charge control agent include benzoic acid metal salts, salicylic acid metal salts, benzylic acid metal salts, alkylsalicylic acid metal salts, copper phthalocyanine, perylene, quinacridone, azo pigments, metal-containing bisazo dyes, and calixarene. Type phenolic condensate, cyclic polysaccharide, trimethylethane compound, catechol metal salt, nigrosine compound, tetraphenylborate derivative, quaternary ammonium salt, onium compound, toniphenylmethane compound, alkylpyridinium salt, chlorination Examples thereof include polyester and nitrofunic acid.
Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides, and magnetic materials such as Fe, Co, and Ni. The thing etc. which were comprised with the magnetic material containing a metal are mentioned.

In addition to the above materials, the constituent material (component) of the core region 11 includes, for example, zinc stearate, zinc oxide, cerium oxide, silica, titanium oxide, iron oxide, fatty acid, fatty acid metal salt, and the like. It may be used.
Further, the proportion of the core region 11 in the toner particles 1 is preferably 40 to 99.5 vol%, and more preferably 60 to 93 vol%. When the ratio of the core region 11 is within the above range, the configuration of the core region 11 can be achieved while the toner particles 1 have sufficiently excellent durability, storage stability (heat resistant storage property, long-term storage property, etc.) and the like. The characteristics of the material can be exhibited more effectively.

The average particle diameter _{D C} of the core region 11 is preferably in the range of 2.0～9.8Myuemu, and more preferably 3.0～5.5Myuemu. When the average particle diameter D _C of the core region 11 is within this range, in the core region 11, it is possible to contain a sufficient amount of colorant, the toner coloring property (coloring density) was particularly excellent Can be. If the average particle diameter D _C of the core region 11 is within this range, it is possible to suitably applied to high-resolution imaging is advantageous in improving the low-temperature fixing property, also, the core region The characteristics of the constituent material 11 and the characteristics of the constituent material of the shell region 12 can be more reliably exhibited.

  The core region 11 may be formed by any method, but is preferably formed by combining a plurality of fine particles. Thereby, the circularity of the toner particles 1 can be made moderately high, and the toner transfer efficiency and cleaning properties can be made particularly excellent. Further, the toner can be particularly excellent in low-temperature fixability.

[Shell area]
The shell region 12 has a composition different from that of the core region 11 and is provided so as to cover the outer periphery of the core region 11. Thus, by having the shell region that covers the core region 11, for example, the toner particles 1 have excellent fixing properties while sufficiently improving the durability and storage stability (heat resistance storage property, long-term storage property, etc.). The fixing good range, which is the temperature range that can maintain the stability (temperature range that can sufficiently prevent the occurrence of offset), can be made sufficiently wide, and the offset in the high temperature range is surely prevented, and the fixing in the low temperature range is ensured. The ease of property (low-temperature fixability) can be made excellent.
Moreover, the shell area | region 12 is comprised with the material containing resin and a coloring agent. As described above, by including the colorant in the shell region 12, it is possible to make the toner durability, storage stability, and toner color development (color density) particularly excellent.

(resin)
The resin constituting the shell region 12 is not particularly limited, but preferably has a composition different from that of the resin constituting the core region 11. As a result, for example, the low temperature fixability of the toner is particularly excellent, and the storage stability (heat resistant storage stability, long-term storage stability, etc.) and durability of the toner can be particularly excellent.

  Moreover, it is preferable that resin which comprises the shell area | region 12 is comprised by the polyester-type resin. As a result, the durability and storage stability (heat resistant storage stability, long-term storage stability, etc.) of the toner particles 1 can be made particularly excellent. In particular, since the core region 11 and the shell region 12 are made of a material containing a polyester-based resin, the toner particles 1 are sufficiently excellent in durability and storage stability (heat resistant storage property, long-term storage property, etc.). In addition, the ease of fixing in a low temperature region (low temperature fixing property) can be made particularly excellent. Moreover, it is preferable that the shell area | region 12 is comprised by the polyester B as described below among polyester-type resin.

[Polyester B]
Polyester B may be composed of a single resin component or may be composed of two or more resin components.
The glass transition temperature Tg (B) of the polyester B is not particularly limited, but is preferably lower than the glass transition temperature Tg (A) of the polyester A described above. As a result, the offset in the high temperature region is surely prevented, the durability and storage stability (heat resistant storage property, long-term storage property, etc.) of the toner particles 1 are sufficiently excellent, and the fixing property in the low temperature region is reduced. The ease (low temperature fixability) can be made particularly excellent.

  Specifically, the glass transition temperature Tg (B) of the polyester B is preferably 60 to 100 ° C, and more preferably 65 to 90 ° C. When the glass transition temperature Tg (B) of the polyester B is a value within the above range, a sufficiently good fixing range which is a temperature range where the excellent fixability can be maintained (a temperature range where the occurrence of offset can be sufficiently prevented) is sufficiently wide. The toner particles 1 can be made particularly excellent in durability, storage stability (heat resistant storage stability, long-term storage stability, etc.) and the like.

  Further, the softening temperature T1 / 2 (B) of the polyester B is not particularly limited, but is preferably lower than the softening temperature T1 / 2 (A) of the polyester A, specifically 60 to 220 ° C. It is preferable that it is 80-200 degreeC. When the softening temperature T1 / 2 (B) of the polyester B is a value within the above range, it is possible to more effectively prevent the occurrence of offset in a high temperature region and to particularly reduce the amount of volatile organic compounds. it can.

The weight average molecular weight Mw (B) of the polyester B is not particularly limited, but is preferably larger than the weight average molecular weight Mw (A) of the polyester A. Thereby, the durability and storage stability of the toner particles 1 can be improved.
Specifically, the weight average molecular weight Mw (B) of the polyester B is preferably 100,000 to 400,000, and more preferably 150,000 to 250,000. When the weight average molecular weight Mw (B) of the polyester B is a value within the above range, the occurrence of offset in a high temperature region can be more effectively prevented, and the amount of volatile organic compounds can be particularly small. .

  The acid value AV (B) of the polyester B is not particularly limited, but is preferably larger than the acid value AV (A) of the polyester A. Thereby, it is possible to more reliably prevent the constituent material of the core region 11 and the constituent material of the shell region 12 from being mixed, and the core region 11 and the shell region 12 are reliably separated from each other. It can have a structure (core-shell structure).

  Specifically, the acid value AV (B) of the polyester B is preferably 6.0 to 20.0 KOHmg / g, and more preferably 8.0 to 18.0 KOHmg / g. When the acid value AV (B) of the polyester B is a value within the above range, it is possible to more reliably prevent the constituent material of the core region 11 and the constituent material of the shell region 12 from being compatible with each other. 1 may have a structure in which the core region 11 and the shell region 12 are reliably separated (core-shell structure). Further, during the production of the toner as will be described in detail later, the coalesced particles corresponding to the core region 11 can be reliably covered with the coating composed of the constituent material of the shell region 12, and the core-shell structure can be obtained. The toner particles 1 can be efficiently produced.

  The content of polyester B in the toner particles 1 is not particularly limited, but is preferably 1 to 30 wt%, and more preferably 2 to 18 wt%. When the content of the polyester B is within the above range, the core region 11 composed of the polyester A and the shell region 12 composed of the polyester B are more reliably separated in the toner particles 1. The characteristics of polyester A and polyester B can be exhibited more effectively. More specifically, the low-temperature fixability of the toner is sufficiently excellent, and offset in the high temperature region is more reliably prevented, and the durability and storage stability of the toner particles 1 (heat storage stability, long-term storage stability, etc.) ) And the like can be made particularly excellent.

  Examples of the polybasic acid component constituting the polyester B include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid; maleic anhydride, fumar Aliphatic carboxylic acids such as acid, succinic acid, alkenyl succinic anhydride, and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and the like, and one or more selected from these may be used in combination Can do. Of these polybasic acids, aromatic carboxylic acids are preferably used.

  Examples of the polyhydric alcohol component constituting the polyester B include aliphatics such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, trimethylolpropane, and pentaerythritol. Diols; cycloaliphatic diols such as cyclohexanediol, cyclohexanedimethanol and hydrogenated bisphenol A; aromatic diols such as ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A, etc. One or two or more selected can be used in combination. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.

Polyester B contains a polybasic acid component having three or more carboxyl groups in one molecule and / or a polyhydric alcohol component having three or more hydroxyl groups in one molecule as a constituent component. There may be.
In addition, the polyester B may contain structural components (structural raw material) other than a polybasic acid component and a polyhydric alcohol component. For example, polyester B may contain a monocarboxylic acid and / or a monoalcohol as a constituent component (constituent monomer). Thereby, for example, the acid value of polyester B can be suitably adjusted. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride, and the like. Examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, trifluoroethanol, trichloroethanol, hexafluoroisopropanol, phenol and the like, and one or more selected from these are used. Can be used in combination.

  Polyester B may contain a polyvalent epoxy compound as a constituent component. Thereby, polyester B can have a suitable crosslinked structure. Examples of the polyvalent epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, ethylene glycol diglycidyl ether, hydroquinone diglycidyl ether, N, N-diglycidyl aniline, glycerin triglycidyl ether. , Trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetrakis 1,1,2,2 (p-hydroxyphenyl) ethane tetraglycidyl ether, cresol novolac type epoxy resin, phenol novolac type epoxy Resin, polymer of vinyl compound having epoxy group (including copolymer), epoxidized resorcinol-acetone condensate, partial Epoxidized polybutadiene, semi-drying or drying fatty acid ester epoxy compound and the like may be used alone or in combination of two or more selected from these. Among them, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether Pentaerythritol tetraglycidyl ether is preferred.

  Specific examples of the bisphenol A type epoxy resin include, for example, Epicron 850, Epicron 1050, Epicron 2055, Epicron 3050 and the like manufactured by Dainippon Ink and Chemicals, Inc. Specific examples of the bisphenol F type epoxy resin include, for example, Examples include Epicron 830 and Epicron 520 manufactured by Dainippon Ink & Chemicals, Inc. Specific examples of the cresol novolak epoxy resin include, for example, Epicron N-660, Epicron N-665 and Epicron manufactured by Dainippon Ink and Chemicals, Inc. N-667, Epicron N-670, Epicron N-673, Epicron N-680, Epicron N-690, Epicron N-695 and the like. Specific examples of phenol novolac type epoxy resins include, for example, Dainippon Ink Chemical Epi made by industry Ron N-740, EPICLON N-770, EPICLON N-775, include EPICLON N-865 or the like. Moreover, as a polymer of the vinyl compound which has an epoxy group, the homopolymer of a glycidyl (meth) acrylate, an acrylic copolymer, a copolymer with styrene, etc. are mentioned, for example.

  Polyester B may contain a monoepoxy compound as a constituent component. Thereby, fixing property and offset resistance at high temperature can be made particularly excellent. Examples of the monoepoxy compound include phenyl glycidyl ether, alkylphenyl glycidyl ether, alkyl glycidyl ether, phenyl glycidyl ester, glycidyl ether of alkylphenol alkylene oxide adduct, α-olefin oxide, monoepoxy fatty acid alkyl ester, and the like. One or two or more selected from can be used in combination. Of these, alkyl glycidyl esters are preferred. Specific examples of the alkyl glycidyl ester include neodecanoic acid glycidyl ester (manufactured by Shell Japan, Cardura E).

  Polyester B can be produced by a condensation reaction using components such as the above-mentioned polyhydric alcohol component and polybasic acid component. For example, the above components are mixed in a reaction vessel equipped with a thermometer, a stirrer, and a flow-down condenser, heated at 150 to 250 ° C. in the presence of an inert gas such as nitrogen, and then further under a reduced pressure atmosphere. By proceeding the reaction, stopping the reaction when a predetermined physical property value is reached, and cooling, the desired reactant (polyester B) can be obtained. As described above, by performing the reaction under a reduced pressure atmosphere, it is effective to continuously remove by-product low molecular weight compounds out of the reaction system and to leave unreacted raw materials in the polyester B as a product. Can be prevented. Thereby, the amount of volatile organic compounds (VOC) as the polyester B can be suppressed.

  Polyester B may be synthesized, for example, using a catalyst. Examples of the catalyst (esterification catalyst) include organic metals such as dibutyltin dilaurate and dibutyltin oxide; metal alkoxides such as tetrabutyl titanate and the like. Further, when the carboxylic acid component to be used is a lower alkyl ester, a transesterification catalyst can be used. Examples of the transesterification catalyst include metal acetates such as zinc acetate, lead acetate, and magnesium acetate; metal oxides such as zinc oxide and antimony oxide; metal alkoxides such as tetrabutyl titanate. About the addition amount of a catalyst, it is preferable to set it as the range of 0.01-1 wt% with respect to the total amount of a raw material.

The above-described polyester A and polyester B preferably satisfy the following relationship.
That is, the difference Tg (B) −Tg (A) between the glass transition temperature Tg (B) of polyester B and the glass transition temperature Tg (A) of polyester A is preferably 5 to 50 ° C., More preferably, it is 40 degreeC. As a result, the offset in the high temperature region is surely prevented, the durability and storage stability (heat resistant storage property, long-term storage property, etc.) of the toner particles 1 are sufficiently excellent, and the fixing property in the low temperature region is reduced. The ease (low temperature fixability) can be made particularly excellent.

  The ratio Mw (B) / Mw (A) between the weight average molecular weight Mw (B) of the polyester B and the weight average molecular weight Mw (A) of the polyester A is preferably 3 to 80, and is preferably 4 to 60. It is more preferable that As a result, in the toner particles, the core region 11 made of the polyester A and the shell region 12 made of the polyester B can be more reliably separated, and the characteristics of the polyester A and the polyester B are more effective. Can be demonstrated. More specifically, the low-temperature fixability of the toner can be made particularly excellent while sufficiently improving the durability and storage stability (heat-resistant storage stability, long-term storage stability, etc.) of the toner particles 1. .

  The ratio α / β between the content α [wt%] of polyester A contained in the toner and the content β [wt%] of polyester B contained in the toner is preferably 3 to 10, More preferably, it is 4-8. As a result, offset in the high temperature region is reliably prevented, and the durability and storage stability (heat resistant storage property, long-term storage property, etc.) of the toner particles are sufficiently excellent, and the fixing property in the low temperature region is easy. The thickness (low-temperature fixability) can be made particularly excellent.

(Coloring agent)
As the colorant constituting the shell region 12, for example, a pigment, a dye, or the like can be used. Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, chrome lead, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S. , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth 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, fast violet B, methyl violet lake, bitumen, cobalt blue, al Reblue Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide, and magnetic materials containing magnetic metals such as Fe, Co, and Ni. Further, the colorant constituting the shell region 12 may be substantially composed of a single substance (pure substance), or may be a mixture of plural kinds of substances.

As described above, the colorant concentration C _S [wt%] in the shell region 12 has a relationship of C _C ≦ C _{S with} the colorant concentration C _C [wt%] in the core region 11. In particular, it is preferable that the following conditions are satisfied.
That is, the concentration _{C S} of the colorant in the shell region 12 is preferably from 6.0～22.0Wt%, and more preferably 8.0~19.0wt%. When the concentration C _S of the colorant in the shell region 12 is within this range, the toner particles 1 strength can be assumed that the shape stability particularly superior durability of the toner, the storage stability It can be particularly excellent. Further, the color developability (color density) of the toner can be made particularly excellent.

Moreover, it is preferable that the average particle diameter of the coloring agent (2nd coloring agent) contained in the shell area | region 12 is 1-50 nm, and it is more preferable that it is 3-30 nm. As a result, it is possible to make the toner storability (heat-resistant storability, long-term storability, etc.), durability, and the like particularly excellent, while sufficiently improving the color developability of the toner.
Colorant contained in the shell region 12 (second coloring agent), with the colorant contained in the core region 11 (first colorant), long as it satisfies the relation C _C ≦ C _S However, it is preferable that the following relationship is satisfied.

The colorant concentration C _C [wt%] in the core region 11 and the colorant concentration C _S [wt%] in the shell region 12 may satisfy the relationship C _C ≦ C _S. However, it is preferable to satisfy the relationship of 0.08 ≦ C _C / C _S ≦ 0.78, and it is more preferable to satisfy the relationship of 0.15 ≦ C _C / C _S ≦ 0.60. By satisfying such a relationship, the durability, storage stability (heat resistant storage stability, long-term storage stability, etc.), and color developability (coloring density) are particularly excellent while sufficiently improving the low-temperature fixability of the toner. Can be.

  Moreover, it is preferable that the colorant (first colorant) contained in the core region 11 and the colorant (second colorant) contained in the shell region 12 have different average particle diameters. . In particular, the average particle size of the colorant (second colorant) contained in the shell region 12 is smaller than the average particle size of the colorant (first colorant) contained in the core region 11. Is more preferable. As a result, the toner can be particularly excellent in low-temperature fixability, durability, and storability (heat-resistant storability, long-term storability, etc.).

In particular, the average particle size of the colorant (first colorant) contained in the core region 11 is d ₁ [nm], and the average particle size of the colorant (second colorant) contained in the shell region 12 is When d ₂ [nm] is satisfied, it is preferable that the relationship 0.05 ≦ d ₂ / d ₁ ≦ 0.80 is satisfied, and the relationship 0.15 ≦ d ₂ / d ₁ ≦ 0.40 is satisfied. Is more preferable. By satisfying such a relationship, the toner can be made particularly excellent in low-temperature fixability, durability, and storage stability (heat-resistant storage property, long-term storage property, etc.).

In addition, the colorant (first colorant) contained in the core region 11 and the colorant (second colorant) contained in the shell region 12 preferably have different compositions. Accordingly, it is possible to provide a toner having a desired color tone (a color tone that is difficult to express with a single colorant) while having excellent low-temperature fixability, durability, and storage stability.
By the way, in the past, when trying to contain a plurality of different colorants in toner particles formed through granulation in a liquid phase as described later, each colorant is surely contained in a desired ratio. It was difficult to express the subtle color tone with certainty. This is because the affinity of each colorant to the liquid (dispersion medium) used in the production of toner differs from the affinity of each colorant to the resin, depending on the type of colorant, and the outflow into the liquid (dispersion medium). This is thought to be due to the different degrees. On the other hand, as in the present invention, the colorant contained in the core region and the colorant contained in the shell region are different from each other after the colorant is contained in the core region and the shell region. By doing so, the influence of the outflow as described above can be eliminated, and a toner having a desired color tone can be obtained easily and reliably.

(Other ingredients)
The shell region 12 may contain components other than those described above. Examples of such components include resins other than polyester B, waxes, charge control agents, magnetic powders, and the like. Moreover, as a constituent material (component) of the shell region 12, in addition to the above-described materials, for example, zinc stearate, zinc oxide, cerium oxide, silica, titanium oxide, iron oxide, fatty acid, fatty acid metal salt, etc. It may be used.

  Examples of the resin include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene- Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid ester copolymer, styrene-α-chloro A homopolymer or copolymer containing styrene or a styrene substitution product, such as a methyl acrylate copolymer, a styrene-acrylonitrile-acrylic acid ester copolymer, a styrene-vinyl methyl ether copolymer, or an epoxy resin, Urethane modified epoxy resin, silico Modified epoxy resin, vinyl chloride resin, rosin modified maleic acid resin, phenyl resin, polyethylene resin, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral Examples thereof include resins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins.

  Examples of the wax include hydrocarbon waxes such as ozokerite, cercin, paraffin wax, microwax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, methyl palmitate , Methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, fatty acid ester, polyglycerin fatty acid ester and other ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, Olefinic wax such as oxidized polypropylene wax, 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide Amide wax, laurone, ketone waxes such as stearone, ether waxes, and the like, can be used singly or in combination of two or more of them.

Examples of the charge control agent include benzoic acid metal salts, salicylic acid metal salts, benzylic acid metal salts, alkylsalicylic acid metal salts, copper phthalocyanine, perylene, quinacridone, azo pigments, metal-containing bisazo dyes, and calixarene. Type phenolic condensate, cyclic polysaccharide, trimethylethane compound, catechol metal salt, nigrosine compound, tetraphenylborate derivative, quaternary ammonium salt, onium compound, toniphenylmethane compound, alkylpyridinium salt, chlorination Examples thereof include polyester and nitrofunic acid.
Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides, and magnetic materials such as Fe, Co, and Ni. The thing etc. which were comprised with the magnetic material containing a metal are mentioned.

Moreover, as a constituent material (component) of the shell region 12, in addition to the above-described materials, for example, zinc stearate, zinc oxide, cerium oxide, silica, titanium oxide, iron oxide, fatty acid, fatty acid metal salt, etc. It may be used.
Further, the thickness of the shell region 12 is not particularly limited, but is preferably 80 to 1000 nm, and more preferably 120 to 600 nm. When the thickness of the shell region 12 is a value within the above range, a sufficient amount of colorant (second colorant) can be contained in the shell region 12, and the color development property (color density) of the toner, The durability and storage stability (heat resistant storage stability, long-term storage stability, etc.) of the toner particles 1 can be made particularly excellent.

Further, when the average thickness of the shell region 12 is L [nm] and the average particle diameter of the colorant (second colorant) contained in the shell region 12 is d ₂ [nm], 0.03 ≦ d ₂ It is preferable to satisfy the relationship /L≦0.25, and it is more preferable to satisfy the relationship 0.04 ≦ d ₂ /L≦0.20. As a result, the color development property (color density) of the toner, the durability of the toner particles 1, storage stability (heat resistant storage property, long-term storage property, etc.) and the like can be made particularly excellent.

As described above, the core region 11 and the shell region 12 each contain a colorant, so that the low-temperature fixability of the toner is sufficiently excellent, and the content of the colorant as a whole of the toner particles 1 is increased. Can be increased. As a result, the amount of toner required to form an image having a predetermined density (color density) can be reduced, the cost required for image formation can be reduced, and it is advantageous from the viewpoint of resource saving. is there.
The content of the colorant with respect to the entire toner particles 1 is preferably 4.0 to 15.0 wt%, and more preferably 6.0 to 10.0 wt%. Thereby, the above effects can be exhibited more remarkably.

[Configuration other than the core area and shell area]
Further, the toner particles 1 may have a configuration other than the core region 11 and the shell region 12. For example, an external additive may be provided in the vicinity of the surface of the toner base particles (toner base particles having the core region 11 and the shell region 12) configured as described above. Examples of external additives include silica, aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, titania, zinc oxide, magnetite and other metal oxides, nitrides such as silicon nitride, and silicon carbide. Fine particles composed of inorganic materials such as carbides, calcium sulfate, calcium carbonate, aliphatic metal salts, etc., fine particles composed of organic materials such as acrylic resins, fluororesins, polystyrene resins, polyester resins, aliphatic metal salts, etc. Fine particles composed of these composites can be used, and one or more selected from these can be used in combination. As the external additive, the surface of the fine particles as described above is subjected to a surface treatment with HMDS, a silane coupling agent, a titanate coupling agent, a fluorine-containing silane coupling agent, silicone oil or the like. It may be used.
<Toner particle shape>
The average particle diameter of the toner particles 1 as described above is not particularly limited, but is preferably 3.0 to 10.0 μm, and more preferably 3.0 to 6.2 μm. When the average particle diameter of the toner particles 1 is within the above range, the toner is sufficiently excellent in low temperature fixability, and particularly excellent in durability, storage stability, and color developability (color density). be able to. Further, it can be suitably applied to high-resolution image formation.
The toner particles constituting the toner preferably have a uniform shape and a sharp particle size distribution (small width).

Specifically, the average circularity R of the toner particles represented by the following formula (I) is preferably 0.95 to 0.99. When the average circularity R is a value within the above range, the toner transfer efficiency is particularly excellent, and the cleaning property in the image forming apparatus is sufficiently excellent.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner particles to be measured, and L ₀ [μm] is a perfect circle having an area equal to the area of the projected image of the toner particles to be measured (completely (Represents the perimeter of a geometric circle)

The standard deviation of the circularity of the toner particles is preferably 0.04 or less. As described above, when the standard deviation of the circularity is sufficiently small, variations in charging characteristics, fixing characteristics, and the like are particularly small, and the reliability of the entire toner is further improved.
In addition, a toner particle expressed as a value (σ (D _T ) / D _T ) × 100 obtained by dividing the standard deviation (σ (D _T )) of the particle diameter of the toner particle by the average particle diameter (D _T ) of the toner particle. The coefficient of variation of the particle size is preferably 24.0 or less, and more preferably 22.0 or less. Thereby, the particle size distribution of the toner particles becomes particularly sharp, and an image formed using the toner can be made better. In addition, variations in charging characteristics and fixing characteristics among the toner particles can be made particularly small, and the reliability of the entire toner can be made particularly excellent. In addition, for example, when the toner is manufactured, the toner can be easily and reliably dried, and the water content in the toner can be suppressed.

When the 50% volume particle diameter of the toner particles is Dv (50) [μm] and the 50% number particle diameter is Dn (50) [μm], the value of Dv (50) / Dn (50) is It is preferable that it is 1.00-1.25, and it is more preferable that it is 1.05-1.15. Thereby, the image formed using the toner can be improved.
In addition, the value of Dv (50) and Dn (50) can be calculated | required by the measurement using the multisizer II type | mold (aperture tube diameter: 100 micrometers) by a Coulter company, for example.

The toner particles as described above can be easily and reliably obtained by the method described below.
The toner particles 1 as described above may be manufactured by any method, but a plurality of dispersoids contained in an O / W type emulsion are combined (in particular, as described later). It is preferable that it is manufactured by the method described above. Thereby, the circularity of the toner particles 1 can be made moderately high, and the toner transfer efficiency and cleaning properties can be made particularly excellent. Further, the toner can be particularly excellent in low-temperature fixability. Further, in the conventional method, when an attempt is made to produce a toner containing a plurality of types of colorants using a method of combining a plurality of dispersoids contained in an O / W type emulsion, Since the degree of outflow to the dispersion medium (aqueous dispersion medium) varies greatly depending on the type, it was extremely difficult to produce a toner containing each colorant in a desired ratio. Also in the production method using a type emulsion, a toner containing each colorant in a desired ratio can be produced reliably.
The toner of the present invention may be used as a one-component developer or may be used as a two-component developer. Further, the toner of the present invention may be used as a dry toner or may be used for a liquid developer.

<Toner production method>
Next, a preferred embodiment of the toner manufacturing method as described above will be described. In the following description, it is assumed that the core region is made of the material containing the polyester A described above, and the shell region is made of the material containing the polyester B described above.
In the manufacturing method of the present embodiment, a dispersion (emulsion suspension) in which a dispersoid composed of a material including a resin material and a colorant (first colorant) is dispersed (emulsified and / or suspended) is obtained. A step of preparing (emulsified suspension preparation step), a step of combining a plurality of dispersoids to obtain coalesced particles (a coalescing step), and a surface of the coalesced particles with a resin material and a colorant (first 2 (coloring agent) and a step of coating with a film composed of a material (coating step).

[Emulsion suspension preparation process (dispersion preparation process)]
First, the emulsion suspension preparation process will be described.
The emulsified suspension prepared in this step is used for forming the core region 11 of the toner particles 1.
The emulsified suspension may be prepared by any method. For example, a colored resin liquid that is a liquid containing polyester A, a colorant (first colorant), and an organic solvent (organic solvent) is used as an aqueous medium. It can be prepared by mixing with.
As the resin material constituting the colored resin liquid, polyester A or a precursor thereof (for example, a prepolymer, a monomer, a dimer, a trimer, an oligomer, or the like) as the constituent material of the core region 11 described above can be used.

  Examples of the organic solvent (organic solvent) include ketone solvents such as methyl ethyl ketone (MEK), diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), cyclohexanone, 3-heptanone, and 4-heptanone. n-butanol, i-butanol, t-butanol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, n-hexanol, cyclohexanol, 1-heptanol, 1-octanol, 2-octanol, 2 -Alcohol solvents such as methoxyethanol, allyl alcohol, furfuryl alcohol, phenol, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, Ether solvents such as trahydrofuran (THF), tetrahydropyran (THP), anisole, diethylene glycol dimethyl ether (diglyme), 2-methoxyethanol, cellosolv solvents such as methyl cellosolve, ethyl cellosolve, phenyl cellosolve, hexane, pentane, heptane , Cyclohexane, methylcyclohexane, octane, didecane, methylcyclohexene, isoprene and other aliphatic hydrocarbon solvents, toluene, xylene, benzene, ethylbenzene, naphthalene and other aromatic hydrocarbon solvents, dichloromethane, chloroform, 1,2-dichloroethane , Halogenated solvents such as trichloroethylene, chlorobenzene, carbon tetrachloride, ethyl acetate, methyl acetate, isopropyl acetate, isobutyl acetate, isopentyl acetate Ester solvents such as ethyl chloroacetate, butyl chloroacetate, isobutyl chloroacetate, ethyl formate, isobutyl formate, ethyl acrylate, methyl methacrylate, ethyl benzoate, nitrile solvents such as acrylonitrile and acetonitrile, nitromethane, nitroethane, etc. Nitro solvent etc. are mentioned, What mixed 1 type, or 2 or more types selected from these can be used.

As the organic solvent, the solubility in 100 parts by weight of water at 25 ° C. is preferably 5 to 45 parts by weight, more preferably 5 to 40 parts by weight.
The boiling point of the organic solvent (boiling point at normal pressure (1 atm); hereinafter the same) is preferably lower than the boiling point of water. Thereby, the organic solvent can be recovered efficiently.
Examples of the organic solvent that satisfies the above conditions include ketone solvents such as methyl ethyl ketone and methyl isopropyl ketone, and ester solvents such as ethyl acetate and isopropyl acetate. Among them, methyl ethyl ketone and ethyl acetate are preferable because the polyester resin (polyester A) has high solubility and dispersibility.

  The colored resin liquid can be obtained, for example, by mixing a resin material, a colorant (first colorant), and a material containing an organic solvent with a stirrer such as a high-speed stirrer. The colored resin liquid is prepared by, for example, kneading a composition containing a resin material and a colorant (first colorant) in advance, and mixing the kneaded material obtained by kneading with an organic solvent. May be prepared. Examples of the stirrer that can be used for the preparation of the colored resin liquid include DESPA (manufactured by Asada Tekko), K. Robotics / T. K. Homodisper 2.5 type wing (manufactured by PRIMIX Co., Ltd.).

The blade tip speed during mixing using a stirrer is preferably, for example, 4 to 30 m / sec, and more preferably 10 to 25 m / sec. When the blade tip speed is a value within the above range, the resin material can be efficiently dissolved and dispersed in the organic solvent, and the colorant (first colorant) in the colored resin liquid ( The dispersion state of the first colorant can be made more uniform. On the other hand, if the blade tip speed is less than the lower limit, depending on the resin material, the colorant (first colorant), the composition of the organic solvent, etc., the colorant (first colorant in the colored resin liquid). ) May be insufficiently dispersed. On the other hand, when the blade tip speed exceeds the upper limit, heat generation due to shearing may increase depending on the composition of the organic solvent, and it may be difficult to perform uniform stirring in combination with volatilization of the organic solvent.
Moreover, it is preferable that the material temperature at the time of stirring is 20-60 degreeC, and it is more preferable that it is 30-50 degreeC.
In the resulting colored resin liquid, the resin material and the colorant (first colorant) are dissolved or dispersed in an organic solvent.

The solid content in the colored resin liquid is not particularly limited, but is preferably 40 to 75 wt%, and more preferably 50 to 73 wt%. When the solid content is within the above range, the dispersoid constituting the emulsified suspension described later can have a higher sphericity (a shape close to a true sphere), and finally Thus, the shape of the toner particles 1 obtained can be more surely suitable.
The colored resin liquid may contain an emulsifier (dispersant). Thereby, the dispersibility of the dispersoid in the emulsified suspension described in detail later can be easily made particularly excellent.

  As the emulsifier, those generally used as a dispersant, a dispersion stabilizer, and a surfactant can be applied. Specific materials that can be applied as an emulsifier include, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ether, Nonionic emulsifiers such as oxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, various pluronics, anionic emulsifiers such as alkyl sulfates, alkyl sulfonates, alkyl benzene sulfonates, quaternary ammonium Examples include cationic emulsifiers such as salts, and one or more selected from these can be used in combination. Of these, alkylbenzene sulfonate is preferred as the emulsifier. As a result, the dispersibility of the dispersoid in the emulsified suspension is particularly excellent, and even if the emulsifier remains in the final toner, it adversely affects the charging characteristics of the toner particles. Can be effectively prevented, and an increase in the amount of VOC (volatile organic compound) can be effectively prevented. Examples of the alkyl group that the alkylbenzene sulfonate has include hexyl, heptyl, octyl, nonanyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl Group and the like, and a dodecyl group is preferable. That is, the alkyl benzene sulfonate is preferably dodecyl benzene sulfonate. As a result, the dispersibility of the dispersoid in the emulsified suspension is further improved, and even if the emulsifier remains in the final toner, the charging characteristics of the toner particles are adversely affected. Can be more effectively prevented, and an increase in the amount of VOC (volatile organic compound) can be more effectively prevented.

  The amount of the emulsifier to be used is preferably 0.1 to 3.0 wt%, more preferably 0.3 to 2.0 wt% with respect to the solid content. If the amount of the emulsifier to be used is less than the lower limit, the effect of preventing the generation of coarse particles may not be sufficiently obtained. On the other hand, when the amount of the emulsifier used exceeds the upper limit, in the coalescence step described later, coalescence of the dispersoid does not sufficiently proceed, and fine particles smaller than a predetermined particle size remain, yielding colored resin fine particles. May be reduced.

The colored resin liquid may contain a wax, a charge control agent, magnetic powder and the like as described above as components other than the resin material, the colorant (first colorant), and the organic solvent. .
In the preparation of the colored resin liquid, all the components of the colored resin liquid to be prepared may be mixed at the same time, or a part of the components of the colored resin liquid to be prepared may be mixed in advance. Master) and then the mixture (master) may be mixed with other ingredients.
For example, a colorant (first colorant) and a resin material are kneaded to obtain a colorant master as a kneaded product, and then the colorant master, the resin material (additional resin), and an organic solvent are mixed. By doing so, a colored resin liquid may be prepared. Thereby, the colored resin liquid with which each component was mixed uniformly can be obtained more reliably.

  When the polyester A includes at least three types of resin components having different weight average molecular weights, that is, the polyester A includes a first resin component and a second resin component having a weight average molecular weight larger than that of the first resin component. And the third resin component having a weight average molecular weight smaller than that of the first resin component, the first resin component is used for the preparation of the colorant master, and the colorant master is used as the second resin component. A colored resin solution may be prepared by mixing with a resin component, the third resin component, and an organic solvent. Thereby, in an emulsified suspension, a colorant (1st colorant) can be more reliably included in the dispersoid comprised with the material containing polyester A. FIG. As a result, toner particles having a desired color density can be produced easily and reliably.

  When using polyester A containing the first resin component, the second resin component, and the third resin component as described above, the weight average molecular weight of each resin component satisfies the following conditions: It is preferable that That is, the weight average molecular weight of the first resin component is preferably 1000 to 5500, and more preferably 1500 to 5000. Further, the weight average molecular weight of the second resin component is preferably 5500 to 100,000, and more preferably 7000 to 80,000. Further, the weight average molecular weight of the third resin component is preferably 100,000 to 300,000, and more preferably 120,000 to 280000. By satisfying these conditions, in the emulsified suspension, the colorant (first colorant) can be more reliably included in the dispersoid composed of the material containing polyester A. Toner particles having a coloring concentration can be produced more reliably.

  In addition, when using wax as a constituent component of the colored resin liquid, for example, a material containing a wax, a resin material, and an organic solvent is mixed to obtain a wax master, and this wax master is used as a colorant master, a resin material ( The colored resin liquid may be prepared by mixing with an additional resin) and an organic solvent. In preparation of the wax master, a wax dispersion liquid (so-called wax emulsion) in which wax particles are dispersed in an aqueous dispersion medium may be used.

An emulsified suspension is prepared by mixing the colored resin liquid as described above with an aqueous medium.
As the aqueous medium, those mainly composed of water can be used.
The aqueous medium may contain, for example, a solvent having excellent compatibility with water (for example, a solvent having a solubility in 100 parts by weight of water at 25 ° C. of 50 parts by weight or more).
The aqueous medium may contain an emulsifier (dispersant).

  In preparing the emulsified suspension, for example, a neutralizing agent may be used. Thereby, for example, the functional group (carboxyl group) of the polyester-based resin (polyester A) can be neutralized, and the shape and size uniformity of the dispersoid in the prepared emulsion suspension, the dispersoid Can be made particularly excellent in dispersibility. In addition, by using a neutralizing agent, the dispersibility of the dispersoid can be sufficiently improved without using an emulsifier or without using an emulsifier. The occurrence of inconvenience due to can be prevented. For example, when a relatively large amount of emulsifier is used, a relatively high shearing force is required during preparation of the emulsion suspension, thereby generating coarse particles (coarse dispersoid) and particle size distribution of the dispersoid. However, such a problem can be prevented by performing neutralization with a neutralizing agent.

For example, the neutralizing agent may be added to the colored resin liquid, or may be added to the aqueous medium.
Further, the neutralizing agent may be added in a plurality of times in the preparation of the emulsion suspension. For example, after adding a neutralizing agent to the colored resin liquid prepared as described above, the colored resin liquid (colored resin liquid to which a neutralizing agent has been added) and an aqueous medium are mixed, and then, You may add a neutralizing agent in a liquid mixture. Thereby, it is possible to easily obtain an emulsified suspension in which the dispersoid is uniformly and finely dispersed while effectively suppressing an increase in the viscosity of the liquid during mixing of the colored resin liquid and the aqueous medium.

  As the neutralizing agent, a basic compound can be used. More specifically, for example, inorganic salts such as sodium hydroxide, potassium hydroxide and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine can be used. 1 type or 2 types or more selected from these can be used. The neutralizing agent may be an aqueous solution containing the above compound.

  Moreover, the usage-amount of a basic compound has the quantity (1-3 equivalent) equivalent to 1-3 times the quantity required in order to neutralize all the carboxyl groups which polyester-type resin (polyester A) has, 1 An amount corresponding to ˜2 times (1 to 2 equivalents) is more preferred. Thereby, it is possible to effectively prevent the formation of irregular dispersoids, and it is possible to make the particle size distribution of the particles obtained in the coalescence step described in detail later sharper.

  Water after dripping water in the emulsified suspension obtained in this step (water used for emulsification, water from the wax dispersion (so-called wax emulsion) used to prepare the wax master, neutralized base) The ratio of the total amount of water and the like to the organic solvent is preferably 50:50 to 80:20, and more preferably 60:40 to 80:20, by volume ratio. As a result, the shape, size uniformity, and dispersibility of the dispersoid in the prepared emulsion suspension can be made particularly excellent.

  The mixing of the colored resin liquid and the aqueous medium may be performed by any method, but the aqueous medium is gradually added (dropped) to the colored resin liquid while shearing the colored resin liquid with a stirrer or the like. It is preferable to finally obtain a dispersion in which the dispersoid derived from the colored resin liquid is dispersed in the aqueous medium. Thereby, for example, an emulsified suspension in which the dispersoid is uniformly and finely dispersed can be obtained easily and reliably.

Examples of the stirrer that can be used for the preparation of the emulsified suspension include DESPA (manufactured by Asada Tekko Co., Ltd.), T.C. K. Robotics / T. K. Examples thereof include a high-speed stirrer such as a homodisper 2.5-type blade (manufactured by Primics), a slasher (manufactured by Mitsui Mining Co., Ltd.), a Cavitron (manufactured by Eurotech), or a high-speed disperser.
The blade tip speed during mixing using a stirrer is preferably, for example, 4 to 30 m / sec, and more preferably 10 to 25 m / sec. When the blade tip speed is a value within the above range, an emulsified suspension can be obtained efficiently, and the dispersion of the shape and size of the dispersoid in the emulsified suspension can be made particularly small. The uniform dispersibility of the dispersoid can be made particularly excellent. On the other hand, if the blade tip speed is less than the lower limit, it may be difficult to sufficiently achieve fine dispersion of the dispersoid in the emulsion suspension. On the other hand, if the blade tip speed exceeds the upper limit, the mixture liquid of the colored resin liquid and the aqueous medium may be scattered violently during mixing, and insoluble materials may be mixed.
Moreover, it is preferable that the material temperature at the time of stirring is 20-60 degreeC, and it is more preferable that it is 20-50 degreeC.

[Joint process]
Next, a plurality of dispersoids are coalesced to obtain coalesced particles (a coalescence step). The obtained coalesced particles (colored resin fine particles) correspond to the core region 11 of the toner particles 1 to be manufactured. The coalescence of dispersoids usually proceeds by fusion of dispersoids containing an organic solvent so that they are fused.
A method for combining a plurality of dispersoids is not particularly limited, but a method of adding an electrolyte to the dispersion is preferable. Thereby, the content rate of the coloring agent (1st coloring agent) contained in coalesced particle can be controlled easily and reliably. In addition, the particle size of the coalesced particles (colored resin fine particles) can be controlled easily and reliably by adjusting the amount of electrolyte added.

Examples of the electrolyte include magnesium sulfate, ammonium sulfate, potassium sulfate, sodium hydrogen sulfate, ammonium hydrogen sulfate, magnesium sulfate, sodium phosphate, sodium dihydrogen phosphate, sodium chloride, potassium chloride, ammonium chloride, calcium chloride, sodium hydrogen carbonate. And salts such as ammonium hydrogen carbonate and sodium acetate, and acidic substances such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid and oxalic acid. One or more selected from these can be used in combination. . Of these, monovalent cation sulfates (for example, sodium sulfate and ammonium sulfate) and carbonates are preferable.
The addition of the electrolyte may be performed in a plurality of times. Thereby, colored resin fine particles (unified particles) of a desired size can be obtained easily and reliably, and the circularity of the obtained colored resin fine particles (unified particles) is surely sufficiently large. can do.

The amount of the electrolyte added in this step is not particularly limited, but is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the solid content of the dispersion to which the electrolyte is added. More preferred are parts by weight.
The electrolyte is preferably added in the form of an aqueous solution. As a result, the electrolyte can be quickly diffused throughout the dispersion, and the amount of electrolyte added can be easily and reliably controlled.

Although the processing temperature in this process is not specifically limited, It is preferable that it is 10-50 degreeC, and it is more preferable that it is 15-40 degreeC. If the processing temperature is less than the lower limit, the coalescence progresses slowly, and the toner productivity may decrease. On the other hand, when the treatment temperature exceeds the upper limit, undesired aggregates and coarse particles are likely to be generated.
This step is preferably performed while the dispersion is stirred. Thereby, coalesced particles with particularly small variations in shape and size among the particles can be obtained.

  In this step, for example, an agitation blade such as an anchor blade, a turbine blade, a fiddler blade, a full zone blade, a max blend blade, or a half moon blade may be used. Among these, a max blend blade or a full zone blade is preferable. Thereby, it can prevent more reliably that the coalesced particle (colored resin fine particle) once formed collapse | disintegrates, uniting a dispersoid efficiently. As a result, coalesced particles with small variations in shape and particle size among the particles can be obtained efficiently.

  The blade tip speed of the stirring blade is, for example, preferably 0.1 to 10 m / second, and more preferably 0.2 to 8 m / second. When the blade tip speed is a value within the above range, it is possible to more reliably prevent the coalesced particles once formed from collapsing while more efficiently coalescing the dispersoid. As a result, coalesced particles with particularly small variations in shape and particle size among the particles can be obtained efficiently. On the other hand, when the blade tip speed is less than the lower limit, stirring is not uniform, and coarse particles coarsened more than necessary are likely to be generated. On the other hand, if the blade tip speed exceeds the upper limit, fine particles that do not contribute to the formation of coalesced particles tend to remain.

When the coalesced particles reach the desired particle size, coalescence is stopped. Thereby, the coalesced particle | grains of a desired particle size can be obtained reliably.
Methods for stopping coalescence include, for example, a method of increasing the stirring speed, a method of lowering the temperature of the dispersion (dispersion in which coalesced particles are dispersed), a method of adding water to the dispersion, The method etc. which combined 2 or more are mentioned. Among them, as a method for stopping coalescence, it is preferable to use a method of adding water to the dispersion. As a result, the coalescence of dispersoids can be quickly stopped while reliably preventing unintentional coalescence particles from further coalescence or collapse. As a result, a toner having a desired particle size and a sharp particle size distribution can be reliably obtained. When the coalescence is stopped by adding water to the dispersion, the organic solvent contained in the dispersoid is extracted by the added water, and the dispersoid particles become hard. As a result, it is considered that coalescence is stopped and collapse of the coalesced particles is surely prevented.

In the case where coalescence is stopped by adding water to the dispersion, the total amount of water contained in the dispersion is 400 weights with respect to 100 parts by weight of the organic solvent contained in the dispersion. It is preferable to add so that it may become more than part, and it is more preferable to add so that it may become 500 parts by weight or more.
Further, when coalescence is stopped by adding water to the dispersion, water is added so that the solid content is 18 to 25 wt% after the addition of water (after the coalescence is stopped). Is preferred. As a result, it is possible to produce a suitable toner with small variations in size and shape while sufficiently suppressing the amount of organic solvent and water used during the production of the toner.

[Coating process]
Next, a film made of a material containing a resin material and a colorant (second colorant) is formed on the surface of the coalesced particles (colored resin fine particles) as described above (covering step).
The film formed in this step corresponds to the shell region 12 of the toner particle 1 to be formed.

The film is formed by, for example, mixing a film forming liquid that is a liquid containing a resin material, a colorant (second colorant), and an organic solvent, and a dispersion liquid in which the coalesced particles are dispersed. This can be done.
As a resin material constituting the film, polyester B or a precursor thereof (for example, a prepolymer, a monomer, a dimer, a trimer, an oligomer, or the like) as the constituent material of the shell region 12 described above can be used.

As an organic solvent which comprises the liquid for film formation, what was illustrated as a constituent material of the colored resin liquid mentioned above can be used, for example.
The organic solvent that constitutes the film forming liquid and the organic solvent that constitutes the colored resin liquid described above may have substantially the same composition, or may have different compositions. However, it is preferable that at least a common component is included. Thereby, a film can be efficiently formed on the surface of the coalesced particles.

The film forming liquid may be, for example, a dispersion in which a dispersoid composed of a material including a resin material is finely dispersed in an aqueous dispersion medium (aqueous medium). Thereby, while forming a film easily and reliably, the uniformity of the thickness of the film formed can be improved.
Moreover, the resin material which comprises the film forming liquid may be neutralized with a neutralizing agent. Thereby, for example, the dispersibility of the coalesced particles (dispersoid) in a state where a film is formed can be made particularly excellent.
Various conditions such as the type of neutralizing agent, the amount added, and the addition method can be the same as described in the emulsion suspension preparation step described above, for example. Thereby, the same effect as described above can be obtained.

Mixing of the dispersion liquid in which the coalesced particles are dispersed and the film-forming liquid may be performed by any method, but the coalesced particles are added to the dispersion liquid in which the coalesced particles are dispersed by a stirrer or the like. It is preferable to carry out by gradually adding (dropping) the film-forming liquid into the dispersion liquid in which is dispersed. Thereby, a film having a uniform thickness can be formed easily and reliably.
In the mixing of the dispersion liquid in which the coalesced particles are dispersed and the film forming liquid, for example, an anchor blade, a turbine blade, a Faudler blade, a full zone blade, a Max blend blade, a meniscus blade, and the like can be used. Among these, a Max blend blade and a full zone blade are preferable. As a result, it is possible to efficiently form a film with small variations in film thickness.

The blade tip speed of the stirring blade is, for example, preferably 0.1 to 10 m / second, and more preferably 0.2 to 8 m / second. When the blade tip speed is within the above range, it is possible to efficiently form a coating having a uniform thickness while reliably preventing unintentional coalescence of dispersoids.
Moreover, it is preferable that the material temperature at the time of stirring is 20-60 degreeC, and it is more preferable that it is 20-50 degreeC.
Further, an electrolyte may be added at the time of mixing the dispersion liquid in which the coalesced particles are dispersed and the film forming liquid. Thereby, the content rate of the coloring agent (2nd coloring agent) contained in the film formed can be controlled easily and reliably. In addition, a film having a desired thickness can be formed more efficiently.

  Examples of the electrolyte include magnesium sulfate, ammonium sulfate, potassium sulfate, sodium hydrogen sulfate, ammonium hydrogen sulfate, magnesium sulfate, sodium phosphate, sodium dihydrogen phosphate, sodium chloride, potassium chloride, ammonium chloride, calcium chloride, sodium hydrogen carbonate. And salts such as ammonium hydrogen carbonate and sodium acetate, and acidic substances such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid and oxalic acid. One or more selected from these can be used in combination. . Of these, monovalent cation sulfates (for example, sodium sulfate and ammonium sulfate) and carbonates are preferable.

The amount of the electrolyte added in this step is not particularly limited, but is preferably 0.1 to 6 parts by weight, and 0.3 to 4 parts by weight with respect to 100 parts by weight of the solid content of the film forming liquid. More preferably.
The electrolyte is preferably added in the form of an aqueous solution. As a result, the electrolyte can be quickly diffused throughout the mixed liquid (mixed liquid of the dispersion liquid in which the coalesced particles are dispersed and the film forming liquid), and the amount of the electrolyte added can be controlled easily and reliably. Can do.

[Desolvation (desolvation) step]
Thereafter, the organic solvent contained in the dispersion is removed (desolvent process). Thereby, toner particles 1 are obtained.
The removal of the organic solvent may be performed by any method, but can be performed, for example, under reduced pressure. Thereby, the organic solvent can be efficiently removed while sufficiently preventing the modification of the constituent material such as the resin material.

Further, the treatment temperature in this step is preferably a temperature lower than the glass transition point (Tg) of the resin material constituting the film (the resin constituting the shell region 12 in the finally obtained toner particles). .
Moreover, you may perform this process in the state which added the antifoamer to the dispersion liquid. Thereby, an organic solvent can be removed efficiently.

Antifoaming agents include, for example, mineral oil-based antifoaming agents, polyether-based antifoaming agents, silicone-based antifoaming agents, lower alcohols, higher alcohols, fats and oils, fatty acids, fatty acid esters, phosphoric acid Esters can be used.
Although the usage-amount of an antifoamer is not specifically limited, It is preferable that it is 20-300 ppm by weight ratio with respect to the solid content contained in a dispersion liquid, and it is more preferable that it is 30-100 ppm.

In this step, at least a part of the aqueous medium may be removed together with the organic solvent.
In this step, unreacted raw materials (monomers and the like) contained in the dispersion can be removed together with the organic solvent. As a result, the amount of volatile organic compounds (VOC) in the finally obtained toner can be made particularly small.
In this step, it is not always necessary to remove all of the organic solvent (the total amount of the organic solvent contained in the dispersion). Even in such a case, the organic solvent remaining in the washing step and the drying step described later can be sufficiently removed.

[Washing process]
Next, the toner particles 1 are cleaned (cleaning step).
By performing this step, even when an organic solvent, an unreacted raw material (monomer, etc.), etc. are contained as impurities, these can be efficiently removed. As a result, the amount of volatile organic compounds (VOC) in the finally obtained toner can be made particularly small.
In this step, for example, the toner particles are separated by solid-liquid separation (separation from an aqueous medium), and then the solid content (toner) is redispersed in water and separated into solid and liquid (separation of toner particles from the aqueous medium). It can be done by doing. The redispersion of solid content (toner) in water and solid-liquid separation may be repeated a plurality of times.

[Drying process]
Thereafter, a final toner can be obtained by performing a drying process (drying step).
The drying step can be performed using, for example, a vacuum dryer (for example, ribocorn (manufactured by Okawara Seisakusho), nauter (manufactured by Hosokawa Micron) etc.), fluidized bed dryer (manufactured by Okawara Seisakusho), etc.
Moreover, it is preferable that the process temperature in this process is a temperature lower than the glass transition point (Tg) of the resin constituting the shell region 12.
In addition, the toner manufacturing method may include an external addition step of applying an external additive as necessary.

<Image forming apparatus>
Next, an image forming apparatus to which the toner of the present invention described above is applied will be described.
3 is an overall configuration diagram illustrating a preferred embodiment of an image forming apparatus to which the toner of the present invention is applied, FIG. 4 is a cross-sectional view of a developing device included in the image forming apparatus of FIG. 3, and FIG. FIG. 6 is a perspective view showing a detailed structure of a fixing device used in the image forming apparatus shown in FIG.

  An image carrier 30 including a photosensitive drum is disposed in the apparatus main body 20 of the image forming apparatus 10 and is rotationally driven in a direction indicated by an arrow by a driving unit (not shown). Around the image carrier 30, an electrostatic latent image is formed on the image carrier 30, a charging device 40 for uniformly charging the image carrier (photoconductor) 30 along the rotation direction. There are provided an exposure device 50, a rotary developing device 60 for developing an electrostatic latent image, and an intermediate transfer device 70 for primary transfer of a monochromatic toner image formed on the image carrier 30.

In the rotary developing device 60, a yellow developing device 60Y, a magenta developing device 60M, a cyan developing device 60C, and a black developing device 60K are mounted on a support frame 600, and the support frame 600 is driven to rotate by a motor (not shown). It is the composition which becomes. The plurality of developing devices 60Y, 60C, 60M, and 60K are selectively rotated so that the developing roller 604 of one developing device faces the image carrier 30 every rotation of the image carrier 30. Has been. Each of the developing devices 60Y, 60C, 60M, and 60K has a toner storage portion that stores toner of each color.
The developing devices 60Y, 60C, 60M, and 60K all have the same structure. Therefore, although the structure of the developing device 60Y will be described here, the structures and functions of the developing devices 60C, 60M, and 60K are the same.

  As shown in FIG. 4, in the developing device 60Y, a supply roller 603 and a developing roller 604 are axially attached to a housing 601 that accommodates toner T therein, and when the developing device 60Y is positioned at the development position described above. The developing roller 604 functioning as a “toner carrier” is positioned in contact with the image carrier (photoreceptor) 30 or with a predetermined gap therebetween, and these rollers 603 and 604 are provided on the main body side. It is configured to be engaged with a rotation drive unit (not shown) and to rotate in a predetermined direction. The developing roller 604 is formed in a cylindrical shape from a metal or alloy such as copper, stainless steel, or aluminum so that a developing bias is applied.

  In the developing device 60Y, a regulating blade 605 for regulating the thickness of the toner layer formed on the surface of the developing roller 604 to a predetermined thickness is disposed. The regulating blade 605 is composed of a plate-like member 605a such as stainless steel or phosphor bronze, and an elastic member 605b such as rubber or resin member attached to the tip of the plate-like member 605a. The rear end portion of the plate-like member 605a is fixed to the housing 601, and the elastic member 605b attached to the front end portion of the plate-like member 605a is the rear end portion of the plate-like member 605a in the rotation direction D3 of the developing roller 604. It arrange | positions so that it may be located in the upstream rather than.

The intermediate transfer device 70 includes a driving roller 90 and a driven roller 100, an intermediate transfer belt 110 that is driven by the two rollers in the direction indicated by the arrow, and a primary transfer that is disposed on the back surface of the belt 110 so as to face the image carrier 30. A roller 120, a transfer belt cleaner 130 for removing residual toner on the belt 110, and a drive roller 90 are arranged to face the four-color full-color image formed on the intermediate transfer belt 110 on a recording medium (paper or the like). And a secondary transfer roller 140 for transferring the toner to the ink.
A paper feed cassette 150 is disposed at the bottom of the apparatus main body 20, and a recording medium in the paper feed cassette 150 passes through a pickup roller 160, a recording medium conveyance path 170, a secondary transfer roller 140, and a fixing device 190, and a paper discharge tray. It is comprised so that it may be conveyed by 200. Reference numeral 230 denotes a duplex printing conveyance path.

  The operation of the image forming apparatus having the above configuration will be described. When an image forming signal is input from a computer (not shown), the image carrier 30, the developing roller 604 of the developing device 60 and the intermediate transfer belt 110 are rotationally driven. First, the outer peripheral surface of the image carrier 30 is charged by the charging device 40. The exposure device 50 selectively exposes the outer peripheral surface of the uniformly charged image carrier 30 according to the image information of the first color (for example, yellow) so that the yellow electrostatic latent image is obtained. An image is formed.

  On the other hand, in the developing device 60Y, the two rollers 603 and 604 rotate while being in contact with each other, whereby yellow toner is rubbed against the surface of the developing roller 604, and a toner layer having a predetermined thickness is formed on the surface of the developing roller 604. . Then, the elastic member 605b of the regulating blade 605 elastically contacts the surface of the developing roller 604, and the toner layer on the surface of the developing roller 604 is regulated to a predetermined thickness.

  At the position of the latent image formed on the image carrier 30, the yellow developing device 60 </ b> Y rotates and the developing roller 604 comes into contact therewith, whereby the yellow electrostatic latent image toner image is transferred onto the image carrier 30. Next, the toner image formed on the image carrier 30 is transferred onto the intermediate transfer belt 110 by the primary transfer roller 120. At this time, the secondary transfer roller 140 is separated from the intermediate transfer belt 110.

The above processing is repeated for the second, third, and fourth colors of the image formation signal, and the latent image formation, development, and transfer are repeated by one rotation of the image carrier 30 and the intermediate transfer belt 110. Four color toner images corresponding to the contents of the image are superimposed and transferred on the intermediate transfer belt 110. Then, at the timing when the full-color image reaches the secondary transfer roller 140, the recording medium is supplied from the recording medium conveyance path 170 to the secondary transfer roller 140. At this time, the secondary transfer roller 140 is pressed against the intermediate transfer belt 110. At the same time, a secondary transfer voltage is applied, and the full-color toner image on the intermediate transfer belt 110 is transferred onto the recording medium. The toner image transferred onto the recording medium is fixed by being heated and pressed by the fixing device 190. The toner remaining on the intermediate transfer belt 110 is removed by the transfer belt cleaner 130.
In the case of double-sided printing, the recording medium exiting the fixing device 190 is switched back so that its trailing edge is the leading edge, supplied to the secondary transfer roller 140 via the double-sided printing conveyance path 230, and intermediate The full color toner image on the transfer belt 110 is transferred onto the recording medium, and is again heated and pressed by the fixing device 190 to be fixed.
In FIG. 3, a fixing device 190 according to the present invention includes a fixing roller 210 having a heat source and a pressure roller 220 pressed against the fixing roller 210. The shafts of the fixing roller 210 and the pressure roller 220 are connected to each other from a horizontal line. It arrange | positions so that it may have the angle of (theta). Note that 0 ° ≦ θ ≦ 30 °.

Next, the fixing device 190 will be described in detail.
In FIG. 5, a fixing roller 210 is rotatably mounted in the housing 240. A pressure roller 220 is rotatably mounted facing the fixing roller 210. The axial length of the pressure roller 220 is shorter than that of the fixing roller 210, and a bearing 250 is provided in the vacant space, and both ends of the pressure roller 220 are supported by the bearing 250. A pressure lever 260 is rotatably provided on the bearing 250, and a pressure spring 270 is disposed between one end of the pressure lever 260 and the housing 240, whereby the pressure roller 220 and the fixing roller 210 are pressurized. It is configured to be.

  In FIG. 6, a fixing roller 210 includes a metal cylinder 210b having a heat source 210a such as a halogen lamp inside, an elastic layer 210c made of silicon rubber or the like provided on the outer periphery of the cylinder 210b, and the surface of the elastic layer 210c. A surface layer (not shown) made of fluororubber and fluororesin (for example, pertetrafluoroethylene (PTFE)) covered with a rotating shaft 210d fixed to the cylinder 210b. As described above, the toner of the present invention is excellent in low-temperature fixability while containing a sufficient colorant. For this reason, the set temperature of the surface of the fixing roller 210 can be made relatively low. Specifically, in the fixing device 190, the set temperature of the surface of the fixing roller 210 is preferably 100 to 190 ° C, and more preferably 120 to 160 ° C. Thus, it is possible to reliably fix the toner on the recording medium while suppressing energy required for fixing. In addition, it is possible to suitably cope with image formation at a higher speed.

  The pressure roller 220 is formed on the outer periphery of the cylindrical body 220b in the same manner as the metal cylindrical body 220b, the rotating shaft 220d fixed to the cylindrical body 220b, the bearing 250 supporting the rotating shaft 220d, and the fixing roller 210. The elastic layer 220c is provided, and a surface layer (not shown) made of fluororubber or fluororesin coated on the surface of the elastic layer 220c. The thickness of the elastic layer 210c of the fixing roller 210 is extremely smaller than the thickness of the elastic layer 220c of the pressure roller 220, thereby forming a fixing nip portion in which the pressure roller 220 side is recessed in a concave shape.

  As shown in FIGS. 5 and 6, support shafts 290 and 300 are provided on both side surfaces of the housing 240. The support shafts 290 and 300 are respectively provided with the peeling member 310 and the pressure roller 220 on the fixing roller 210 side. The side peeling member 320 is rotatably mounted. As a result, the peeling members 310 and 320 are disposed downstream of the fixing nip portion in the recording medium conveyance direction in the axial direction of the fixing roller 210 and the pressure roller 220.

  In the present embodiment, as shown in FIGS. 5 and 6, peeling members 310 and 320 are disposed on the downstream side of the nip portion in the recording medium conveyance direction in the axial direction of the fixing roller 210 and the pressure roller 220. The tip of the peeling member 310 on the fixing roller 210 side is disposed so as to incline toward the exit of the nip portion, and is not in contact with and close to the fixing roller 210. The leading end of the peeling member 320 on the pressure roller 220 side is disposed downstream of the leading end of the peeling member 310 on the fixing roller 210 side in the recording medium conveyance direction.

  In the case of double-sided printing, the recording medium printed on one side is peeled off by the peeling member 310 on the fixing roller 210 side, and then switched back so that the trailing edge of the recording medium becomes the leading edge, and then passes through the double-sided printing conveyance path 230. The full-color toner image on the intermediate transfer belt 110 is supplied to the secondary transfer roller 140 and is transferred onto the recording medium, and is heated and pressed again by the fixing roller 210. At this time, it adheres to the pressure roller 220 and wraps around. The recording medium is peeled off by the peeling member 320 on the pressure roller 220 side.

  As described above, in the fixing device according to the present embodiment, the peeling is provided in the vicinity of the fixing roller and the pressure roller in the axial direction of the fixing roller and the pressure roller and on the downstream side of the fixing nip portion in the recording medium conveyance direction. The positioning of the peeling member on the fixing roller side is performed on the surface of the fixing roller, and the positioning of the peeling member on the pressure roller side is performed on the bearing surface of the pressure roller, so that recording from the fixing roller and the pressure roller is performed. The peelability of the medium can be improved.

As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to these.
For example, in the above-described embodiment, the toner is described as being manufactured by a method having an emulsion suspension preparation step, a coalescence step, and a coating step. However, the toner of the present invention is such a method. It is not limited to what was manufactured in.

In the above-described embodiment, the solvent removal process is provided after the coating process. For example, the solvent removal process (first solvent removal process) is provided between the coalescence process and the coating process, and the coating process is performed. A solvent removal step (second solvent removal step) may be provided after the step.
The toner particles may have a configuration other than the core region and the shell region. For example, the toner of the present invention may have a plurality of core regions in a single toner particle, and a partition wall made of the same material as the shell region between adjacent core regions. Thereby, for example, the durability and storage stability (heat resistant storage stability, long-term storage stability, etc.) of the toner can be made particularly excellent. In addition, with such a configuration, even when the shell region is relatively thin, the toner particles have particularly excellent durability and storage stability (heat resistance storage property, long-term storage property, etc.). Therefore, the ratio of the core area in the toner particles can be increased. As a result, the characteristics of the constituent material of the core region can be exhibited more effectively, and for example, the low-temperature fixability and color developability can be made particularly excellent.

[1] Toner Production Prior to toner production, resins (resin H1, resin H2, resin H3, resin L1, and resin L2) are synthesized, and a wax master (wax master WM) is synthesized using the synthesized resin. -1), a colorant master (colorant master PM-1, PM-2), and a mill base (mill base MB-1, MB-2) were prepared.

<Synthesis of resin H1 (high molecular weight resin (crosslinked polyester resin))>
Raw materials such as an acid, an alcohol component, and a catalyst having the following composition were put into a 50 liter reaction kettle and reacted at 240 ° C. for 12 hours under a normal pressure nitrogen stream. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point based on ASTM E28-517, and the reaction was terminated when the softening point reached 160 ° C.

Terephthalic acid 9.06 parts by mass Isophthalic acid 3.90 parts by mass Ethylene glycol 2.54 parts by mass Neopentyl glycol 4.26 parts by mass Tetrabutyl titanate 0.1 part by mass Epicron 830 0.3 part by mass Cardura E 0.1 part by mass Parts (however, epiclone 830 is a bisphenol F type epoxy resin manufactured by Dainippon Ink and Chemicals, Inc., and its epoxy equivalent is 170 g / eq. Cardura E is an alkyl glycidyl ester manufactured by Shell Japan.) And the epoxy equivalent is 250 g / eq.)

  The obtained polymer was a colorless solid, and had an acid value of 10.0 KOH mg / g, a glass transition temperature (Tg) of 65 ° C., and a softening point (T1 / 2) of 178 ° C. The glass transition temperature (Tg) was measured using a differential scanning calorimeter (manufactured by Shimadzu Corp., DSC60-A), measuring temperature range: 20 to 150 ° C., heating rate: 6 ° C./min, sample mass: 20 mg. Under the conditions described above, the curve at the time of temperature increase of the second run was obtained by analyzing by the onset method. Moreover, the glass transition temperature was similarly calculated | required also about other resin demonstrated below.

  Further, the weight average molecular weight was measured by using a GPC measuring apparatus (HLC-8120GPC manufactured by Tosoh Corporation) as a separation column in combination with TSK-GEL G5000HXL / G4000HXL / G3000HXL / G2000HXL manufactured by Tosoh Corporation, column temperature: 40 ° C., solvent: tetrahydrofuran, solvent The molecular weight was determined by measuring at a concentration of 0.5% by mass, filter: 0.2 μm, flow rate: 1 ml / min, and conversion using standard polystyrene. As a result, the weight average molecular weight was 230000.

<Synthesis of resin H2 (high molecular weight resin (crosslinked polyester resin))>
Raw materials such as an acid, an alcohol component, and a catalyst having the following composition were put into a 50 liter reaction kettle and reacted at 240 ° C. for 12 hours under a normal pressure nitrogen stream. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point based on ASTM E28-517, and the reaction was terminated when the softening point reached 160 ° C.

Terephthalic acid 1.94 parts by weight Isophthalic acid 9.07 parts by weight Adipic acid 1.71 parts by weight Ethylene glycol 2.54 parts by weight Neopentyl glycol 4.26 parts by weight Tetrabutyl titanate 0.1 parts by weight Epiklone 830 0.3 parts by weight Part Cardura E 0.1 part by mass The obtained polymer was a colorless solid, and had an acid value of 9.8 KOH mg / g, a glass transition temperature (Tg) of 40 ° C., and a softening point (T1 / 2) of 178 ° C. It was. Moreover, the weight average molecular weight was 176000.

<Synthesis of resin H3 (high molecular weight resin (crosslinked polyester resin))>
Raw materials such as an acid, an alcohol component, and a catalyst having the following composition were put into a 50 liter reaction kettle and reacted at 240 ° C. for 12 hours under a normal pressure nitrogen stream. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point according to ASTM E28-517 and terminated when the softening point reached 130 ° C.

Terephthalic acid 3.9 parts by mass Isophthalic acid 9.06 parts by mass Ethylene glycol 2.54 parts by mass Neopentyl glycol 4.26 parts by mass Tetrabutyl titanate 0.1 parts by mass Epicron 830 0.3 parts by mass (Dainippon Ink & Chemicals, Inc.) Bisphenol F type epoxy resin, epoxy equivalent 170 (g / eq)
Cardura E 0.1 parts by mass (Shell Japan alkyl glycidyl ester) epoxy equivalent 250 (g / eq)
The obtained polymer was a colorless solid, and had an acid value of 11.0 KOHmg / g, a glass transition temperature (Tg) of 59 ° C, and a softening point (T1 / 2) of 138 ° C. The weight average molecular weight was 85000.

<Synthesis of Resin L1 (Low Molecular Weight Resin (Linear Polyester Resin))>
Raw materials such as an acid, an alcohol component, and a catalyst having the following composition were put into a 50 liter reaction kettle and reacted at 210 ° C. for 12 hours under a normal pressure nitrogen stream. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point according to ASTM E28-517 and terminated when the softening point reached 87 ° C.

Terephthalic acid 5.31 parts by weight Isophthalic acid 7.97 parts by weight Ethylene glycol 2.6 parts by weight Neopentyl glycol 4.37 parts by weight Tetrabutyl titanate 0.1 parts by weight The obtained polymer is a colorless solid, The acid value was 10.0 KOHmg / g, the glass transition temperature (Tg) was 46 ° C, and the softening point (T1 / 2) was 95 ° C. Moreover, the weight average molecular weight was 5200.

<Synthesis of resin L2 (low molecular weight resin (linear polyester resin))>
Raw materials such as an acid, an alcohol component, and a catalyst having the following composition were put into a 50 liter reaction kettle and reacted at 210 ° C. for 12 hours under a normal pressure nitrogen stream. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point based on ASTM E28-517 and terminated when the softening point reached 104 ° C.

Terephthalic acid 7.97 parts by mass Isophthalic acid 5.31 parts by mass Ethylene glycol 2.6 parts by mass Neopentyl glycol 4.37 parts by mass Tetrabutyl titanate 0.1 part by mass The obtained polymer is a colorless solid, The acid value was 10.0 KOHmg / g, the glass transition temperature (Tg) was 56 ° C, and the softening point (T1 / 2) was 106 ° C. The weight average molecular weight was 8,000.
Table 1 summarizes the physical properties of the resins synthesized as described above.

<Preparation of wax master WM-1>
To a 3 L cylindrical vessel attached to a high-speed emulsifier (Primics Co., Ltd., TK homomixer MARK II2.5 type), water: 1300 parts by weight, sodium dodecylbenzenesulfonate as an emulsifier: 25.7 parts by weight, The temperature was adjusted to 95 ° C., and under stirring at a blade tip speed of 16.7 m / sec, 700 parts by weight of pre-melted carnauba wax was added to obtain a wax emulsion. After cooling, water was added to obtain a first wax dispersion so that the solid content was 35 wt%.

  Next, 856 parts by weight of methyl ethyl ketone was charged into a 3 L cylindrical container attached to a high-speed disperser (manufactured by Primics Co., Ltd., TK Robotics / TK homodisper type 2.5 blade). : 700 parts by weight was gradually added to confirm that the resin L2 was uniformly dissolved, and then the first wax dispersion liquid: 878.6 parts by weight was added to prepare a premixed liquid. . Subsequently, this preliminary mixed liquid was mixed with a star mill (manufactured by Ashizawa Finetech Co., Ltd., LMZ-10) to obtain a wax master WM-1 having a solid content of 45.0 wt%. The composition of the obtained wax master WM-1 was, by weight, resin L2: wax: sodium dodecylbenzenesulfonate: methyl ethyl ketone: water = 31.3: 13.4: 0.3: 29.5: 25.5. Met.

<Preparation of Colorant Master PM-1>
C. I. Pigment Red 122: 2000 parts by weight and Resin L2: 2000 parts by weight were charged into a 20 L Henschel mixer (made by Mitsui Mining Co., Ltd.) with ST / A0 blades set, and the blade tip speed: 10 m / s, stirred for 2 minutes. A mixture was obtained. The mixture was melt-kneaded using an open-roll continuous extrusion kneader (Mitsui Mining Co., Ltd. Needex MOS140-800) to obtain a colorant master PM-1. The composition of the coloring master PM-1 was, as a weight ratio, coloring agent: resin = 50: 50. Further, when the obtained colorant master PM-1 was diluted with resin L2 and methyl ethyl ketone, and the finely dispersed state of the colorant and the presence or absence of coarse particles were observed with a 400-fold optical microscope, no coarse particles were observed. A uniform fine dispersion was observed.

<Preparation of Colorant Master PM-2>
C. I. Pigment Red 57: 1: 2000 parts by weight and Resin H1: 2000 parts by weight are charged into a 20 L Henschel mixer (made by Mitsui Mining Co., Ltd.) equipped with ST / A0 blades, and blade tip speed: 10 m / s for 2 minutes. Stir to obtain a mixture. The mixture was melt-kneaded using an open roll continuous extrusion kneader (Mitsui Mining Co., Ltd. Needex MOS140-800) to obtain a colorant master PM-2. The composition of the coloring master PM-2 was colorant: resin = 50: 50 by weight ratio. Further, when the obtained colorant master PM-2 was diluted with resin H1 and methyl ethyl ketone, and the finely dispersed state of the colorant and the presence or absence of coarse particles were observed with a 400 × optical microscope, no coarse particles were observed. A uniform fine dispersion was observed.

<Preparation of Millbase MB-1>
Methyl ethyl ketone (diluted methyl ethyl ketone): 179.4 is attached to a 2 L cylindrical container (disper blade diameter 40 mm) attached to a high-speed disperser (Primics Co., Ltd., TK Robotics / TK homodisper 2.5 type blade). A part by weight was charged, and 49.8 parts by weight of resin H1 (diluted resin) was further added. In this state, stirring was performed at a blade tip speed of 7.5 m / sec. With stirring, colorant master PM-1: 29.4 parts by weight, resin L2 (diluted resin): 120.8 parts by weight, wax master WM-1: 223.9 parts by weight, and dodecylbenzene as an emulsifier By adding 1.09 parts by weight of sodium sulfonate in this order into the cylindrical container, each component was dissolved and dispersed. Further, methyl ethyl ketone was additionally added so that the solid content was 55 wt%, and Millbase MB-1 was obtained. In addition, the material temperature at the time of stirring was kept at 30-40 degreeC.

<Preparation of Millbase MB-2>
In a 2 L cylindrical container (disper blade diameter 40 mm) attached to a high-speed disperser (Primics Co., Ltd., TK Robotics / TK homodisper 2.5 blade), methyl ethyl ketone (diluted methyl ethyl ketone): 367 parts by weight In addition, 70.8 parts by weight of resin H1 (diluted resin) was added. In this state, stirring was performed at a blade tip speed of 7.5 m / sec. In a stirred state, by adding 105 parts by weight of the colorant master PM-2 and 124.2 parts by weight of the resin H1 (diluted resin) in this order into the cylindrical container, each component is dissolved and dispersed. Went. Thereafter, the material temperature is set to 40 ° C., 80 parts by weight of 1N ammonia water is added, and the blade tip speed is increased to 16.5 m / sec. Under this stirring condition, 701 parts by weight of water is 20 parts by weight / Millbase MB-2 was obtained by dropping at a rate of minutes. Solid content of the obtained mill base MB-2 was 20.72 wt%.

(Example 1)
A toner was manufactured as follows. In addition, about the process (process) in which temperature conditions are not described, it performed at room temperature (25 degreeC) (it is the same also about Example 2 or later).
<< Emulsion suspension preparation process >>
To the same container in which Millbase MB-1 was prepared, 50 parts by weight of 1N ammonia water was subsequently added and stirred at a blade tip speed of 7.5 m / second, and then adjusted to a temperature of 30 ° C. or lower.

  Thereafter, the blade tip speed was changed to 16.5 m / sec. In this state, 350 parts by weight of water (deionized water) was added dropwise at a rate of 20 parts by weight / min, and the dispersion (emulsified suspension) was added. Prepared. As deionized water was added, the viscosity of the system increased, but water was taken into the system at the same time as dropping, and stirring and mixing were uniform. A decrease in viscosity was observed when 200 parts by weight of deionized water was added (phase inversion point). Further, after a predetermined amount of the remaining deionized water was dropped (after 350 parts by weight of deionized water was dropped), 185 parts by weight of water was added as dilution water in a lump. In this dispersion, coarse particles having poor dispersibility were not observed.

<< Unification process >>
Next, after the dispersion was transferred to a Max Blend blade (blade diameter: 65 mm) and a 2 L cylindrical container attached to the condenser, the temperature was adjusted to 25 ° C. while maintaining the blade tip speed: 1.09 m / sec. did.
Thereafter, the blade tip speed of the Max Blend blade was adjusted to 1.53 m / sec, and 120 parts by weight of a 3.5 wt% aqueous sodium sulfate solution was added dropwise at 10 g / min. After completion of dropping, the blade tip speed was reduced from 1.53 m / second to 0.54 m / second over 15 minutes, and further stirred at 0.54 m / second for 20 minutes.

Thereafter, the blade tip speed of the Max Blend blade was adjusted to 1.53 m / second, 40 parts by weight of 5.0 wt% sodium sulfate aqueous solution was dropped, and then the blade tip speed was changed from 1.53 m / second to 0.54 m / second. The mixture was decelerated to 2 seconds, and further stirred at 0.54 m / second for 10 minutes.
Thereafter, the blade speed of the Max Blend blade was adjusted to 1.53 m / sec and stirred for 30 minutes.

  Then, with the blade speed of the Max Blend blade adjusted to 1.53 m / sec, 5.0 wt% sodium sulfate aqueous solution: 10 parts by weight was dropped, and the blade tip speed was changed from 1.53 m / sec to 0.54 m. The speed was reduced to 15 minutes per second, and stirring was further performed at 0.54 m / second for 10 minutes. Here, this dispersion was observed. As a result, a large number of coalesced particles in which a plurality of dispersoids were coalesced were confirmed.

Then, with the blade speed of the Max Blend blade adjusted to 1.53 m / sec, 5.0 wt% sodium sulfate aqueous solution: 10 parts by weight was dropped, and the blade tip speed was changed from 1.53 m / sec to 0.54 m. The process of decelerating over 15 minutes per second and stirring for 10 minutes at 0.54 m / second was further repeated twice (total 3 times).
Then, with the blade speed of the Max Blend blade adjusted to 1.02 m / sec, the mixture was stirred for 30 minutes, and further, 400 parts by weight of water was added to stop the coalescence of the dispersoid. A dispersion liquid in which the coalesced particles (colored resin fine particles) were dispersed was obtained.

<Coating process>
In the 2L cylindrical container in which the above coalescence process was performed, Millbase MB-2: 289.6 parts by weight was dropped at a rate of 5 g / min with the blade speed of the Max Blend blade adjusted to 1.53 m / sec. did. After completion of dropping, the blade speed of the Max Blend blade was reduced from 1.53 m / sec to 0.85 m / sec, and stirring was further performed for 20 minutes while maintaining the blade tip speed. Thereafter, the blade tip speed was adjusted to 1.53 m / sec, and 5.0 wt% sodium sulfate aqueous solution: 20 parts by weight was dropped. Thereafter, the blade tip speed was reduced from 1.53 m / second to 0.54 m / second over 15 minutes, and stirring was performed for 20 minutes while maintaining the blade tip speed. Thereby, the film was formed on the surface of the coalesced particles.

<< Solvent removal process >>
Thereafter, a silicone-based antifoaming agent (manufactured by Dow Corning Toray, BY22-517): 0.034 parts by weight is added, and by reducing the pressure, methyl ethyl ketone and water are used until the solid content becomes 23 wt% or more. A part was distilled off to obtain a slurry (colored resin fine particle slurry).
《Cleaning process》
The slurry obtained as described above was subjected to solid-liquid separation, and further subjected to washing treatment by repeated redispersion in water and solid-liquid separation. Thereafter, a wet cake of colored resin fine particles (colored resin fine particle cake) was obtained by suction filtration.

<< Drying process >>
Then, toner particles were obtained by drying the wet cake using a vacuum dryer. The toner particles were subjected to structural observation by TEM (transmission electron microscope) and measurement of particle diameter. As a result, it was confirmed that the obtained toner particles have a core region containing a colorant and a shell region containing a colorant. Moreover, it confirmed that the content rate of the coloring agent in a shell area | region was higher than the content rate of the coloring agent in a core area | region. Further, when the 50% volume particle diameter of the toner particles is Dv (50) [μm] and the 50% number particle diameter is Dn (50) [μm], Dv (50) is 5.1 μm and Dv ( 50) / Dn (50) was 1.09. Further, the average circularity R of the toner particles was 0.981. Further, the average particle diameter of the core region constituting the toner particles was 4.7 μm, and the average thickness of the shell region was 0.2 μm. Further, the proportion of the core region in the toner particles was 78 vol%. Moreover, the average particle diameter of the colorant (first colorant) contained in the core region was 50 nm. Moreover, the average particle diameter of the colorant (second colorant) contained in the shell region was 10 nm.

The particle size and particle size distribution were measured with Microtrac MT-3000 (Nikkiso Co., Ltd. particle size distribution measuring device). The other particles described below were similarly measured for particle size and particle size distribution.
The average circularity was determined by measurement using a flow particle image analyzer (FPIP-1000, manufactured by Toa Medical Electronics Co., Ltd.). Moreover, the average circularity was calculated | required similarly about the other particle | grains demonstrated below.

(Examples 2 to 5)
Content of colorant and resin in mill base (mill base MB-1) used in emulsion suspension preparation step, average particle size of colorant, and amount of colorant and resin in mill base (mill base MB-2) used in coating step By changing the content ratio, the average particle size of the colorant, and adjusting the amount of sodium sulfate aqueous solution used in the coalescing step, the coating step, the amount of mill base used in the coating step, and the stirring conditions in each step, toner particles A toner was manufactured in the same manner as in Example 1 except that the configuration was changed as shown in Table 2.

(Example 6)
In the coating step, C.I. I. Instead of CI Pigment Red 57: 1, C.I. I. A toner was manufactured in the same manner as in Example 1 except that a mill base containing Pigment Red 122 was used.
(Examples 7 to 10)
Change the content of the colorant and resin in the mill base used in the emulsion suspension preparation process, the average particle diameter of the colorant, the content of the colorant and resin in the mill base used in the coating process, and the average particle diameter of the colorant. In addition, the composition of the toner particles was changed as shown in Table 2 by adjusting the amount of sodium sulfate aqueous solution used in the coalescing step and the coating step, the amount of mill base used in the coating step, and the stirring conditions in each step. Produced a toner in the same manner as in Example 6.

(Example 11)
In the emulsion suspension preparation step, C.I. I. Instead of CI Pigment Red 122, C.I. I. In the coating process, a C.I. I. Instead of CI Pigment Red 57: 1, C.I. I. A toner was manufactured in the same manner as in Example 1 except that a mill base containing Pigment Yellow 74 was used.

(Examples 12 to 15)
Change the content of the colorant and resin in the mill base used in the emulsion suspension preparation process, the average particle diameter of the colorant, the content of the colorant and resin in the mill base used in the coating process, and the average particle diameter of the colorant. In addition, the composition of the toner particles was changed as shown in Table 3 by adjusting the amount of sodium sulfate aqueous solution used in the coalescing step and the coating step, the amount of mill base used in the coating step, and the stirring conditions in each step. Produced a toner in the same manner as in Example 11.
(Examples 16 and 17)
A toner was produced in the same manner as in Example 1 except that the composition of the resin constituting the mill base used in the emulsion suspension preparation step and the composition of the resin constituting the mill base used in the coating step were changed.

(Comparative Example 1)
A toner was manufactured in the same manner as in Example 1 except that a mill base containing no colorant was used in the coating step.
(Comparative Example 2)
The toner was prepared in the same manner as in Comparative Example 1 except that the composition of the toner particles was changed as shown in Table 3 by changing the content of the colorant and the resin in the mill base used in the emulsion suspension preparation step. Manufactured.

(Comparative Example 3)
A toner was produced in the same manner as in Example 1 except that a mill base containing no colorant was used in the emulsion suspension preparation step.
(Comparative Example 4)
By changing the content of the colorant and the resin in the mill base used in the emulsion suspension preparation process and the content of the colorant and the resin in the mill base used in the coating process, the content of the colorant in the core region and the shell region A toner was manufactured in the same manner as in Example 1 except that was changed.

  Tables 2 and 3 collectively show the main components of the toner particles. In the table, C.I. I. Pigment Yellow 185 is changed to “Y185”, C.I. I. Pigment Yellow 74 is changed to “Y74”, C.I. I. Pigment Red 122 is “R122”, C.I. I. Pigment Red 57: 1 is indicated by “R57: 1”. Further, the resin constituting the toner of each example and each comparative example exhibited the same glass transition temperature, softening temperature, and average molecular weight as the resin material used as a raw material.

[2] Evaluation [2.1] Strength of Toner Particles For the toners obtained in each of the above Examples and Comparative Examples, the strength of toner particles at room temperature (25 ° C.) was evaluated. The strength of the toner particles was measured by using a micro compression tester (manufactured by Shimadzu Corporation, MCT-W500), upper pressure indenter: 50 μm diameter flat indenter, lower pressure plate: SKS flat plate, load speed: 0.473988 N / sec, temperature From the test force-displacement graph obtained by measurement under the conditions of: 25 ° C. and humidity: 50%, the load at the time of 7% displacement, the load at the first inflection point and the value of the displacement amount were evaluated. 7% displacement load, the greater the load value at the first inflection point, and the greater the displacement value at the first inflection point, the better the strength. It can be judged.

[2.2] Preservability The toners obtained in the above Examples and Comparative Examples were allowed to stand for 6 months in an environment of 35 ° C. and a relative humidity of 65%. Thereafter, the appearance of the toner was observed and evaluated according to the following five-step criteria.
A: No aggregation of toner particles is observed.
A: Almost no aggregation of toner particles is observed.
○: Slight aggregation of fine toner particles is observed.
Δ: Slight aggregation of relatively large toner particles is observed.
X: Aggregation of relatively large toner particles is noticeable.

[2.3] Image Density For the toners obtained in each of the above Examples and Comparative Examples, the image density was evaluated as follows.
First, an image forming apparatus (color printer) having a configuration as shown in FIGS. Using this image forming apparatus, a toner image having a predetermined pattern was transferred and fixed on a recording medium (high quality plain paper manufactured by Seiko Epson Corporation) to obtain a fixed toner image. In this image forming apparatus, the conveyance speed of the recording medium when the toner passes through the nip portion is set to 150 m / second, and the set temperature of the surface of the fixing roller is set to 140 ° C.
For the fixed toner image on the recording medium obtained as described above, an OD value was measured using a spectrolino manufactured by Gretag Macbeth Co., Ltd. under the conditions of a D50 light source, a viewing angle of 2 °, no filter, and a back black plate. Asked.

C. I. Pigment red 122 and / or C.I. I. Pigment Red 57: 1
The toner containing was evaluated according to the following five-stage criteria.
A: The OD value is 1.6 or more.
A: The OD value is 1.5 or more and less than 1.6.
○: OD value is 1.4 or more and less than 1.5.
Δ: OD value is 1.3 or more and less than 1.4.
X: OD value is less than 1.3.

In addition, C.I. I. Pigment yellow 185, C.I. I. The toner containing CI Pigment Yellow 74 was evaluated according to the following five-step criteria.
A: The OD value is 1.4 or more.
A: OD value is 1.3 or more and less than 1.4.
○: OD value is 1.2 or more and less than 1.3.
(Triangle | delta): OD value is 1.1 or more and less than 1.2.
X: OD value is less than 1.1.

[2.4] Good Fixing Area and Low-Temperature Fixability The toners obtained in the above Examples and Comparative Examples were evaluated for good fixing area and low-temperature fixability as follows.
First, an image forming apparatus (color printer) having a configuration as shown in FIGS. 2 and 3 was prepared except that the fixing apparatus was not provided. Using this image forming apparatus, an unfixed image sample having a toner image transferred onto a recording medium (high quality plain paper manufactured by Seiko Epson Corporation) was collected. The solid amount of the sample to be collected was adjusted to an adhesion amount of 0.5 g / cm ² .

  Next, the recording medium on which the above-described unfixed toner image is transferred in a state where the surface temperature of the fixing roller of the fixing device constituting the image forming apparatus is set to a predetermined temperature is shown in FIGS. By introducing the toner image into the fixing device, the toner image was fixed on the recording medium, and the presence or absence of occurrence of offset after fixing was visually confirmed. In this fixing device, the conveyance speed of the recording medium when the toner passes through the nip portion is set to 150 m / second.

Similarly, the set temperature of the surface of the fixing roller is sequentially changed within a range of 100 to 220 ° C., and the presence / absence of occurrence of offset at each temperature is confirmed. It was determined as “range” and evaluated according to the following four-stage criteria.
A: The width of the good fixing region is 55 ° C. or more.
○: The width of the good fixing region is 45 ° C. or higher and lower than 55 ° C.
(Triangle | delta): The width | variety of a fixing favorable area is 35 to 45 degreeC.
X: The width of the good fixing region is less than 35 ° C.

[2.5] Fixing Strength The fixing strength of the toners obtained in the above Examples and Comparative Examples was evaluated as follows.
First, an image forming apparatus (color printer) having a configuration as shown in FIGS. Using this image forming apparatus, a toner image having a predetermined pattern was transferred and fixed on a recording medium (high quality plain paper manufactured by Seiko Epson Corporation) to obtain a fixed toner image. In this image forming apparatus, the conveyance speed of the recording medium when the toner passes through the nip portion is set to 150 m / second, and the set temperature of the surface of the fixing roller is set to 140 ° C.

The fixed toner image on the recording medium obtained as described above was rubbed once with an eraser (made by Lion Corporation, sand eraser “LION 261-11”) with a pressing load of 1.0 kgf, and the residual ratio of image density Was measured by “X-Rite model 404” manufactured by X-Rite Inc, and evaluated according to the following five-step criteria.
A: Image density residual ratio is 95% or more.
A: Image density residual ratio is 90% or more and less than 95%.
○: Image density remaining rate is 80% or more and less than 90%.
Δ: Image density remaining rate is 70% or more and less than 80%.
X: Image density remaining rate is less than 70%.
These results are shown in Table 4. Table 4 also shows the lower limit value of the good fixing region. The lower this lower limit, the better the low-temperature fixability.

  As is apparent from Table 4, the toner of the present invention had excellent strength and excellent storage stability and durability. Further, with the toner of the present invention, a toner image having a high image density could be suitably formed. Thereby, the amount of toner used can be reduced, which is preferable from the viewpoint of resource saving. In addition, the toner of the present invention has a wide fixing range, excellent low-temperature fixability, and excellent fixing strength to a recording medium. In particular, in Examples 1 to 5, 11 to 15, 16, and 17 in which the composition of the colorant is different between the core region and the shell region, it was possible to easily and reliably perform fine adjustment of the color tone of the toner image. .

  On the other hand, satisfactory results were not obtained with the toners of the comparative examples. In particular, the toners of Comparative Examples 1 and 2 that did not contain a colorant in the shell region had low toner particle strength and poor storage stability and durability. Further, with the toner of Comparative Example 1, a toner image having a sufficiently high image density could not be formed. Further, with the toner of Comparative Example 3 containing no colorant in the core region, a toner image having a sufficiently high image density could not be formed. Further, even in the toner of Comparative Example 4 in which the colorant content in the core region is higher than the colorant content in the shell region, the strength of the toner particles is low, and sufficient storage stability and durability cannot be obtained. It was.

FIG. 3 is a schematic cross-sectional view showing a preferred embodiment of toner particles constituting the toner of the present invention. It is a figure for demonstrating how to obtain | require a softening point, (a) is a quick sectional view which shows the apparatus used for a measurement typically, (b) is the method of calculating | requiring a softening point (T1 / 2) from a measurement result. It is a graph for demonstrating. 1 is an overall configuration diagram illustrating a preferred embodiment of an image forming apparatus to which the toner of the present invention is applied. FIG. 4 is a cross-sectional view of a developing device included in the image forming apparatus of FIG. 3. FIG. 4 is a perspective view showing a detailed structure of a fixing device used in the image forming apparatus of FIG. FIG. 6 is a cross-sectional view of a main part of the fixing device in FIG. 5.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Toner particle 11 ... Core area | region (core part, core) 12 ... Shell area | region (outer shell) 6 ... Nozzle 7 ... Cylinder 8 ... Sample 9 ... Load surface 10 ... Image forming apparatus 20 ... Apparatus main body 30 ... Image carrier 40 ... Charging device 50 ... Exposure device 60 ... Rotary developing device 600 ... Support frame 601 ... Housing 603 ... Supply roller 604 ... Developing roller 605 ... Regulating blade 605a ... Plate-like member 605b ... Elastic member 60Y ... Yellow developing device 60M ... Magenta Developing device 60C ... Developing device for cyan 60K ... Developing device for black 70 ... Intermediate transfer device 90 ... Drive roller 100 ... Drive roller 110 ... Intermediate transfer belt 120 ... Primary transfer roller 130 ... Transfer belt cleaner 140 ... Secondary transfer roller 150 ... Paper cassette 160 ... Pickup roller DESCRIPTION OF SYMBOLS 170 ... Recording-medium conveyance path 190 ... Fixing device 200 ... Discharge tray 210 ... Fixing roller (heat fixing member) 210a ... Heat source 210b ... Cylindrical body 210c ... Elastic layer 210d ... Rotating shaft 220 ... Pressure roller (pressure member) 220b ... Cylinder 220c ... Elastic layer 220d ... Rotary shaft 230 ... Double-sided printing conveyance path 240 ... Housing 250 ... Bearing 260 ... Pressure lever 270 ... Pressure spring 290 ... Support shaft 300 ... Support shaft 310 ... Peeling member 320 ... Peeling member T ... Toner

Claims (8)

A toner containing a large number of toner particles,
The toner particles have a core region and a shell region that covers an outer periphery of the core region and has a composition different from that of the core region.
The core region and the shell region are each composed of a material containing a resin and a colorant,
When the concentration of the colorant in the core region is C _C [wt%] and the concentration of the colorant in the shell region is C _S [wt%], the relationship C _C ≦ C _S is satisfied. Toner. The concentration _{C C} of the colorant in the core region, toner according to claim 1 which is 1.8~6.5wt%. The concentration _{C S} of the colorant in the shell region, toner according to claim 1 or 2 is 6.0~22.0wt%. The concentration C _C [wt%] of the colorant in the core region and the concentration C _S [wt%] of the colorant in the shell region are 0.08 ≦ C _C / C _S ≦ 0.78. The toner according to claim 1, wherein the toner satisfies the following relationship.   The toner according to claim 1, wherein the colorant contained in the core region and the colorant contained in the shell region have different compositions.   The toner according to claim 1, wherein the colorant contained in the core region and the colorant contained in the shell region have different average particle sizes.   The toner according to claim 1, wherein an average thickness of the shell region is 80 to 1000 nm. When the average thickness of the shell region is L [nm] and the average particle diameter of the colorant contained in the shell region is d ₂ [nm], a relationship of 0.03 ≦ d ₂ /L≦0.25 The toner according to claim 1, wherein the toner satisfies the following.

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