JP2008058744A - Toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner in which the functions of external additives are thoroughly exhibited while avoiding the harmful effects of released external additives. <P>SOLUTION: Each toner particle 1 constituting the toner has a toner base particle 11 and the external additives 12 imparted near the surface of the toner base particle 11. The toner base particle 11 is formed by joining a plurality of fine particles 111 and has constricted parts 13 at outer circumferential parts of joint surfaces 112 of the fine particles 111. The external additives 12 is mainly distributed near the constricted parts 113. The constricted parts 113 are provided over the substantially entire circumference of the toner base particle 11 with normals of the joint surfaces 112 as axes. The difference between an average particle diameter L<SB>1</SB>[μm] of the fine particles 111 and an average length L<SB>2</SB>[μm] of the joint surfaces 112 of the fine particles 111 in a protected shape of the toner base particle 11, L<SB>1</SB>-L<SB>2</SB>is preferably 0.7-5.0 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner used in an electrophotographic copying machine, a FAX, a printer, and the like.

  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 usually contains a large number of toner particles composed of a material containing a resin component and a colorant.
Then, for the purpose of improving the fluidity of the toner particles or controlling the charging characteristics of the toner particles, an external additive is applied to the surface of the toner base particles composed of the above materials as toner particles. (For example, refer to Patent Document 1). In general, the external additive is externally added to the toner base particles by mixing the toner base particles and the external additive using a powder mixer such as a Henschel mixer.

  However, conventional toners, particularly toners spheroidized for high image quality (improving transfer efficiency and preventing omission), have been difficult to fully exert the function of external additives. In other words, in conventional toners, it is difficult to reliably hold the external additive near the surface of the toner base particle through durability, and the external additive that was held moderately at the beginning of printing is restricted. By passing under the blade or between the developing roller / supply roller, the amount of external additive (free external additive) that is insufficiently embedded in the toner surface due to external force or scraped off from the toner base particles increases. If a large amount of such a free external additive is contained, the function of the external additive is not fully exhibited, and the free external additive aggregates and adversely affects the components of the image forming apparatus to which the toner is applied. Sometimes. In order to prevent liberation of the external additive, it is conceivable to apply a relatively large shearing force to the mixing of the toner base particles and the external additive. In addition, the external additive is buried, and the toner base particles are deformed and fused due to heat generated by the shearing force. As a result, the function as the external additive cannot be sufficiently exhibited.

JP 2000-137348 A (paragraph numbers 0062 to 0067)

  An object of the present invention is to provide a toner that sufficiently prevents the occurrence of adverse effects due to a liberated external additive and that exhibits the function of the external additive sufficiently. In particular, it is an object to provide a toner that exhibits the function of an external additive that does not cause voids while maintaining high transfer efficiency as a toner through durability.

Such an object is achieved by the present invention described below.
The toner of the present invention is a toner to which an external additive is applied in the vicinity of the surface of the toner base particles,
The toner base particles are formed by joining a plurality of fine particles,
Mainly toner mother particles having a constricted portion on the outer periphery of the bonding surface of the fine particles,
The external additive is unevenly distributed in the vicinity of the constricted portion.
As a result, it is possible to provide a toner that sufficiently prevents the occurrence of adverse effects due to the liberated external additive and sufficiently exhibits the function of the external additive.

In the toner of the present invention, it is preferable that the constricted portion is provided over substantially the entire circumference of the toner base particle with the normal line of the joining surface as an axis.
As a result, the function of the external additive can be exhibited more effectively while preventing the adverse effects of the liberated external additive more effectively.
In the toner of the present invention, the average particle size of the fine particles is preferably 1.0 to 8.5 μm.
Thereby, the function of the external additive can be more effectively exhibited while reliably holding the external additive near the surface of the toner base particles.

In the toner of the present invention, it is preferable that the average length of the bonding surface of the fine particles in the projected shape of the toner base particles is 0.3 to 6.0 μm.
Thereby, the function of the external additive can be more effectively exhibited while reliably holding the external additive near the surface of the toner base particles.
In the toner of the present invention, the difference (L ₁ −L ₂₎ between the average particle diameter L ₁ [μm] of the fine particles and the average length L ₂ [μm] of the bonding surface of the fine particles in the projected shape of the toner base particles. ) Is preferably 0.7 to 5.0 μm.
Thereby, the function of the external additive can be more effectively exhibited while reliably holding the external additive near the surface of the toner base particles.

In the toner of the present invention, the average particle diameter of the external additive is preferably 10 to 500 nm.
Thereby, the function of the external additive can be more effectively exhibited while reliably holding the external additive near the surface of the toner base particles.
The toner of the present invention preferably contains 1.0 to 5.0 parts by weight of the external additive with respect to 100 parts by weight of the toner base particles.
Thereby, the function of the external additive can be exhibited more effectively while preventing the liberated external additive from being generated excessively.

In the toner of the present invention, it is preferable that the toner base particles have an average particle size of 2.0 to 10.0 μm.
Thereby, the function of the external additive can be exhibited more reliably, and the resolution of the image formed using the toner can be made sufficiently high.
In the toner of the present invention, when the average particle size of the toner base particles is L ₀ [μm] and the average particle size of the fine particles is L ₁ [μm], 0.50 ≦ L ₁ / L ₀ ≦ 0.85. It is preferable to satisfy this relationship.
Thereby, the function of the external additive can be more effectively exhibited while reliably holding the external additive near the surface of the toner base particles.

In the toner of the present invention, the ratio of the toner base particles formed by joining the two fine particles to the whole toner base particles constituting the toner is 20 to 80% by number, and three or more fine particles are included. The ratio of the toner base particles formed by bonding is 5 to 45% by number, and the ratio of the toner base particles formed by bonding the two fine particles is formed by bonding three or more of the fine particles. It is preferably larger than the ratio of the toner base particles.
Thereby, the function of the external additive can be more effectively exhibited while reliably holding the external additive near the surface of the toner base particles.

In the toner of the present invention, it is preferable that the average value (average circularity) of the circularity R represented by the following formula (I) for the toner base particles is 0.92 to 0.98.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner base 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 base particles to be measured) Represents the perimeter of
Thereby, the function of the external additive can be more effectively exhibited while reliably holding the external additive near the surface of the toner base particles.

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, FIG. 2 is a diagram for explaining how to determine a softening point, and FIG. 3 is an external addition step. FIG. 4 is a plan view showing an example of a mixing blade included in the external addition treatment tank shown in FIG. 3.

<Toner>
The toner is composed of a large number of toner particles 1.
The toner particles 1 have toner base particles 11 and an external additive 12.
In the toner of the present invention, when the toner base particles are spheroidized to improve transfer efficiency and prevent omission, the external additive is embedded or liberated, and the function of the external additive is difficult to be exhibited. It was invented in view of the above.
That is, the toner base particles are characterized in that two or more fine particles 111 of the same size are joined and formed in the toner base particles, and the constricted portion 113 is provided on the outer periphery of the joint surface 112 of the fine particles. It is.

  The toner base particles and the external additive can be distributed more unevenly around the constricted portion 113 than the overall average on the toner base particles 11 by, for example, a method described later. As a result, the initial amount of free external additive can be reduced. Further, even when a relatively large external force is applied to the toner particles 11 by a blade or the like, the constricted portion 113 in which the external additive is unevenly distributed is not rubbed by the blade or the like, and the external additive 12 is applied to the toner base particles. This unevenly distributed external additive is agitated with other toner in the developing machine and reattached to the scraped portion in the developing machine. It becomes possible to hold in an appropriate state. As a result, the function of the external additive can be fully exerted while sufficiently preventing the adverse effects due to the liberation of the external additive.

  In other words, the constricted portion exhibits a function of controlling the coverage of the toner base particles with the external additive, and as a result, the function of the external additive is sufficiently prevented while sufficiently preventing the adverse effects due to the liberation of the external additive. Can be demonstrated. Further, even when an external force is applied due to uneven distribution of the external additive in the constricted portion, the external additive is hardly embedded, the fluidity is maintained, and the durability is sufficiently maintained.

In addition, since the toner base particles 11 are present as a joined body of the fine particles 111, the contact point between the toner base particles 11 and the transfer body during the image formation maintains substantially the same point contact as the spherical toner. This toner has a high transfer efficiency, and can be a toner in which fine lines in the recording medium hardly occur.
Further, since the toner base particles 11 are present as a joined body of the fine particles 111, the toner can be suitably fixed on the recording medium under milder conditions. More specifically, since the specific surface area of the toner base particles 11 is large with respect to the particle diameter, the whole can be heated relatively uniformly, and variation in temperature within the toner base particles 11 can be suppressed. The toner can be reliably fixed with relatively small energy.

[Toner mother particles]
As will be described in detail later, the toner base particles 11 are made of a material containing a resin component and a colorant.
The presence of the toner base particles 11 as a bonded body of the fine particles 111 enables the cleaning process (cleaning process) and the solvent-removing process (solvent-removing process) to be efficiently performed in the manufacturing method as described later. The content of volatile organic compounds in can be suppressed.

  The average particle diameter of the fine particles 111 constituting the toner base particles 11 is not particularly limited, but is preferably 1.0 to 8.5 μm, and more preferably 2.5 to 7.0 μm. As a result, the function of the external additive 12 can be more effectively exhibited while the external additive 12 is reliably held near the surface of the toner base particles 11. In the present specification, the average particle diameter means a volume-based 50% particle diameter unless otherwise specified.

Further, when the average particle diameter of the toner base particles 11 is L ₀ [μm] and the average particle diameter of the fine particles 111 is L ₁ [μm], the relationship of 0.50 ≦ L ₁ / L ₀ ≦ 0.85 is satisfied. It is preferable that the relationship 0.55 ≦ L ₁ / L ₀ ≦ 0.80 is satisfied. As a result, the function of the external additive 12 can be more effectively exhibited while the external additive 12 is reliably held near the surface of the toner base particles 11.

Further, the difference (L ₁ −L ₂ ) between the average particle diameter L ₁ [μm] of the fine particles 111 and the average length L ₂ [μm] of the bonding surface 112 of the fine particles 111 in the projected shape of the toner base particles 11 is It is preferable that it is 0.7-5.0 micrometers, and it is more preferable that it is 1.0-2.0 micrometers. As a result, the function of the external additive 12 can be more effectively exhibited while the external additive 12 is reliably held near the surface of the toner base particles 11.
Further, the average length of the bonding surface 112 of the fine particles 111 in the projected shape of the toner base particles 11 is preferably 0.3 to 6.0 μm, and more preferably 1.5 to 5.0 μm. As a result, the function of the external additive 12 can be more effectively exhibited while the external additive 12 is reliably held near the surface of the toner base particles 11.

  The constricted portion 113 may be provided on at least a part of the toner base particle 11 (the outer peripheral portion of the bonding surface 112 between the adjacent fine particles 111), but the toner is centered on the normal line of the bonding surface 112. It is preferable to be provided over substantially the entire circumference of the base particle 11. Thereby, the function of the external additive 12 can be exhibited more effectively while preventing the adverse effect of the liberated external additive 12 more effectively.

The toner base particles 11 formed by joining n fine particles 111 can be represented by R _n (where n is a numerical value of 2 or more). For example, the toner base particle 11 formed by joining two fine particles 111 can be represented by R ₂ , and the toner base particle 11 formed by joining three fine particles 111 can be represented by R _3. The toner base particles 11 formed by bonding the fine particles 111 can be represented by R ₄ .

The ratio of the toner base particles 11 (R ₂ ) formed by joining two fine particles 111 to the whole toner base particles 11 constituting the toner is preferably 20 to 80% by number, and preferably 25 to 75% by number. It is more preferable that As a result, the function of the external additive 12 can be more effectively exhibited while the external additive 12 is reliably held near the surface of the toner base particles 11.
Further, the ratio of the toner base particles 11 formed by bonding 3 to 6 fine particles 111 to the entire toner base particles 11 constituting the toner (the sum of the ratios of R ₃ , R ₄ , R ₅ , and R ₆ ). Is preferably 5 to 45% by number, more preferably 7 to 40% by number.

Further, it is preferable that the ratio of the toner base particles in which two fine particles are bonded is larger than the ratio of the mother particles in which three or more particles are bonded. The two joined mother particles have one rotation axis, and the constricted portion exists over the entire outer periphery of the joined portion, so that the effect of the constricted portion can be sufficiently exhibited. As a result, the function of the external additive 12 can be more effectively exhibited while the external additive 12 is reliably held near the surface of the toner base particles 11.
Further, the average particle diameter of the toner base particles 11 is preferably 2.0 to 10.0 μm, and more preferably 3.0 to 8.0 μm. As a result, the function of the external additive 12 can be more reliably exhibited, and the resolution of an image formed using the toner can be made sufficiently high.

The toner base particles 11 preferably have a uniform shape and a sharp particle size distribution (small width).
Specifically, the average circularity R of the toner base particles 11 represented by the following formula (I) is preferably 0.92 to 0.98. When the average circularity R is a value within the above range, the function of the external additive 12 can be more effectively exhibited while reliably holding the external additive 12 near the surface of the toner base particles 11. The toner transfer efficiency can be made particularly excellent, and the cleaning property in the image forming apparatus can be made sufficiently excellent.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner base 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 base particles to be measured) (Represents the perimeter of a complete geometric circle)

The standard deviation of the circularity of the toner base particles 11 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.
Further, when the 50% volume particle diameter of the toner base particles 11 is Dv (50) [μm] and the 50% number particle diameter is Dn (50) [μm], the value of Dv (50) / Dn (50) is obtained. Is preferably 1.00 to 1.25, more preferably 1.00 to 1.20. 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, for example, Multisizer II type (aperture tube diameter: 100 μm) manufactured by Coulter or Microtrack MT3000 manufactured by Nikkiso.
The toner base particles 11 are preferably produced by uniting (joining) a plurality of dispersoids contained in an O / W type emulsion. Thereby, the strength of the toner base particles 11 can be made particularly excellent, and the shape of the toner base particles 11 can be more easily made a desired shape.

Hereinafter, the constituent materials of the toner base particles 11 will be described in detail.
The toner base particles 11 (fine particles 111) are made of a material containing a resin component and a colorant.
The resin component (binder resin) constituting the toner base particles 11 is not particularly limited, and examples thereof include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, and 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- Styrene resin such as acrylic ester-methacrylic ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic ester copolymer, styrene-vinyl methyl ether copolymer, etc. Unipolymers containing styrene substituents or Is a copolymer, polyester resin, epoxy resin, urethane modified epoxy resin, silicone 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 resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, and the like, and one or more of these may be combined Can be used. Among them, the polyester resin is advantageous for improving ease of fixing in a low temperature region (low temperature fixing property), and also advantageous for forming a high gloss image with high transparency. Further, when the toner base particles 11 are made of a polyester resin, a toner having desired characteristics can be manufactured easily and reliably by a manufacturing method as described later.

  The glass transition temperature (Tg) of the resin component (binder resin) constituting the toner base particles 11 is not particularly limited, but is preferably 30 to 85 ° C, and more preferably 35 to 75 ° C. When the glass transition temperature of the resin component constituting the toner base particle 11 is a temperature within the above range, an image (on a recording medium using toner) having excellent low-temperature fixability as a toner ( The fixing strength and the like of the (fixed image) can be made sufficiently excellent. In the case where the toner base particles 11 contain a plurality of types of resin components, the glass transition temperature is the weighted average value of the glass transition temperatures of these components, and the glass of the resin component constituting the toner base particles 11. It can be employed as the transition temperature (Tg).

Further, the softening temperature T1 / 2 of the resin component (binder resin) constituting the toner base particles 11 is not particularly limited, but is preferably 60 to 215 ° C, more preferably 80 to 190 ° C. When the softening temperature T1 / 2 of the resin component constituting the toner base particle 11 is within the above range, the toner is formed on the recording medium using the toner while the low-temperature fixability as the toner is particularly excellent. The fixing strength of the image (fixed image) can be made sufficiently excellent. In the present specification, unless otherwise specified, the softening temperature T1 / 2 is as follows using a flow tester (CFT-500, manufactured by Shimadzu Corporation), which is a constant load extrusion type capillary rheometer. Refers to the required value. 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.

  In the present invention, it is preferable that the toner base particles 11 are made of a material containing a polyester resin. The acid value of the polyester resin is preferably 1 to 30 KOHmg / g, and more preferably 3 to 20 KOHmg / g. When the acid value of the polyester resin is within the above range, the charging property of the toner particles 1 can be stabilized, and the fixing strength to a recording medium such as paper can be particularly excellent. In addition, in the manufacturing method as described later, the generation of coarse particles can be more effectively prevented, and the particle size distribution of the toner particles 1 can be made particularly sharp.

The polyester resin is preferably a mixture of a cross-linked polyester resin and a linear polyester resin, and preferably obtained by reacting a compound selected from the following raw materials.
The cross-linked polyester is preferably produced by reacting a dibasic acid or a derivative thereof, a divalent alcohol, and a polyvalent compound as a cross-linking agent. In particular, it is preferable to produce by reacting a dibasic acid or a derivative thereof, a divalent aliphatic polyhydric alcohol, and a polyvalent epoxy compound as a crosslinking agent.
The linear polyester resin is produced by reacting a dibasic acid with a divalent alcohol. In particular, it is preferable to produce by reacting a dibasic acid with a divalent aliphatic alcohol.

  Acid components used in the production of cross-linked polyester resins and linear polyester resins include phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, adipic acid, maleic acid, maleic anhydride, fumaric acid, itacone Examples thereof include dicarboxylic acids such as acid, citraconic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, azelaic acid, sebacic acid, and derivatives or esterified products thereof.

  Examples of the divalent aliphatic alcohol component include 1,4-cyclohexanedimethanol, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, butanediol, and pentanediol. Hexanediol, polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide random copolymer diol, ethylene oxide-propylene oxide block copolymer diol, ethylene oxide-tetrahydrofuran copolymer diol, polycaprocactone diol, etc. Diols are mentioned.

Use of an aliphatic alcohol in the cross-linked polyester resin and the linear polyester resin is preferable because compatibility with waxes is improved and offset resistance is improved. Moreover, fixing property at low temperature is improved by softening the polyester main chain.
When producing a crosslinked polyester resin, a polyvalent epoxy compound is further used as a crosslinking agent.

  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, or copolymer, epoxidized resorcinol-acetone condensate, partial Epoxidized polybutadiene, polymers of vinyl compounds having an epoxy group, or a copolymer, such as semi-drying or drying fatty acid ester epoxy compound. Among the above compounds, 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, trimethylol ethane Triglycidyl ether and pentaerythritol tetraglycidyl ether are more preferably used.

  Specifically, as examples of bisphenol A type epoxy resin, Epicron 850, Epicron 1050, Epicron 2055, Epicron 3050, etc. manufactured by Dainippon Ink & Chemicals, Inc., Epicron 830 manufactured by Dainippon Ink and Chemicals, Ltd. as examples of bisphenol F type epoxy resins, Epicron 520 and the like are examples of orthocresol novolak type epoxy resins, Epicron N-660, N-665, N-667, N-670, N-673, N-680, N-690, manufactured by Dainippon Ink and Chemicals, Inc. Examples of phenol novolac type epoxy resins such as N-695 include Epicron N-740, N-770, N-775, N-865 and the like manufactured by Dainippon Ink and Chemicals, Inc. Examples of the polymer or copolymer of a vinyl compound having an epoxy group include a homopolymer of glycidyl (meth) acrylate, an acrylic copolymer, and a copolymer with styrene.

Moreover, the epoxy compound mentioned above can also be used in combination of 2 or more types, Furthermore, the mono epoxy compound described below can also be used together as a modifier | denaturant of resin. Examples of monoepoxy compounds that can be used simultaneously include phenyl glycidyl ether, alkylphenyl glycidyl ether, alkyl glycidyl ether, alkyl glycidyl ester, glycidyl ether of alkylphenol alkylene oxide adduct, α-olefin oxide, monoepoxy fatty acid alkyl ester, and the like. Is mentioned.
By using these monoepoxy compounds in combination, fixability and resistance to offset at high temperatures are improved. Among these, alkyl glycidyl esters are particularly preferably used.
A specific example is neodecanoic acid glycidyl ester (Shell Japan Cardura E).

The cross-linked polyester resin and the linear polyester resin can be obtained, for example, by performing a dehydration condensation reaction or a transesterification reaction in the presence of a catalyst using the raw material components described above. The reaction temperature and reaction time in this case can be 2 to 24 hours at 150 to 300 ° C.
As a catalyst for performing the above reaction, for example, tetrabutyl titanate, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, paratoluenesulfonic acid and the like can be used.

  The use ratio of the cross-linked polyester resin and the linear polyester resin used in the present invention is (mass of cross-linked polyester resin) / (mass of linear polyester resin) = 5 / 95-60 / 40. Can do. Moreover, it is good also as 10 / 90-40 / 60 or 20 / 80-40 / 60. By adjusting the ratio of the cross-linked polyester resin, high temperature offset resistance, melt viscosity (T1 / 2 temperature), low temperature fixability and the like can be adjusted.

  The glass transition temperature (Tg) of the cross-linked polyester resin is preferably 40 to 85 ° C, and particularly preferably 40 to 75 ° C. When the glass transition temperature (Tg) is lower than 40 ° C., a blocking phenomenon (thermal aggregation) tends to occur when the toner is stored, transported, or exposed to a high temperature inside the image forming apparatus. Further, if the glass transition temperature (Tg) is higher than 85 ° C., the low-temperature fixability is lowered, which is not preferable.

  The glass transition temperature (Tg) of the linear polyester resin is preferably 35 to 70 ° C, and particularly preferably 35 to 65 ° C. When the glass transition temperature (Tg) is lower than 35 ° C., a blocking phenomenon, that is, thermal aggregation tends to occur when the toner is stored, transported, or exposed to a high temperature inside the image forming apparatus. On the other hand, if the glass transition temperature (Tg) is higher than 70 ° C., the low-temperature fixability is lowered, which is not preferable.

In addition, the softening point of the cross-linked polyester resin is preferably 150 ° C. or higher, and particularly preferably 150 ° C. to 220 ° C. Here, the softening point of the cross-linked polyester resin is more preferably 150 ° C. to 200 ° C., and particularly preferably 150 ° C. to 190 ° C. When the softening point is less than 150 ° C., the toner tends to cause an aggregation phenomenon, which may hinder image formation. On the other hand, if it exceeds 220 ° C., the fixability tends to deteriorate. Moreover, it is preferable that the softening point of a linear polyester resin is 85 degreeC or more, and it is preferable that it is 85 to 130 degreeC especially. Here, the softening point of the linear polyester resin is more preferably 85 ° C to 120 ° C, and particularly preferably 85 ° C to 110 ° C. Similar to the cross-linked polyester resin, when the softening point is less than 85 ° C., the glass transition temperature is lowered, and the toner tends to cause an aggregation phenomenon, and when it exceeds 130 ° C., the fixability is likely to deteriorate. .
Moreover, it is preferable that the softening point of the mixture of cross-linked polyester resin and linear polyester resin is 100 ° C to 150 ° C. When the softening point is less than 100 ° C., the toner tends to cause an aggregation phenomenon, and when it exceeds 150 ° C., the fixability tends to deteriorate.

  Examples of the colorant constituting the toner base particles 11 include carbon black, C.I. I. Pigment Black 11 and other iron oxide pigments, C.I. I. Examples thereof include iron-titanium complex oxide pigments such as Pigment Black 12, or carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black.

  As the blue colorant, phthalocyanine C.I. I. Pigment Blue 1, 2, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15, 16, 17: 1, 27, 28, 29, 56, 60, 63, and the like. Among these, C.I. I. Pigment Blue 15: 3, 15, 16, 60 is preferable. I. Pigment Blue 15: 3, 60 is more preferable.

  Examples of yellow colorants include C.I. I. Pigment Yellow 1, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, 24, 55, 65, 73, 74, 81, 83, 87, 93, 94, 95, 97, 98 , 100, 101, 104, 108, 109, 110, 113, 116, 117, 120, 123, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 156, 168, 169, 170 , 171, 172, 173, 180, 185 and the like. Among these, C.I. I. Pigment Yellow 17, 74, 93, 97, 110, 15.5, 180 are preferable. I. Pigment Yellow 74, 93, 97, 180 is more preferable. I. Pigment Yellow 93, 97, 180 is more preferable.

  Examples of red colorants include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 17, 18, 22, 23, 31, 37, 38, 41, 42, 48: 1, 48 : 2, 48: 3, 48: 4, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53: 1, 54, 57: 1, 58: 4, 60: 1, 63 : 1, 63: 2, 64: 1, 65, 66, 67, 68, 81, 83, 88, 90, 90: 1, 112311, 4, 115, 122, 123, 133, 144, 146, 147, 149 , 150, 151, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 184, 185, 187, 188, 189, 190, 193, 194, 202, 208, 209, 214 , 216, 220, 221 24,242,243,243: 1,245,246,247, and the like. Among these, C.I. I. Pigment Red 48: 1, 48: 2, 48: 3, 48: 4, 53: 1, 57: 1, 122, 184 and 209 are preferred. I. Pigment Red 57: 1, 122, 184 and 209 are more preferable. Among these, one kind or a combination of two or more kinds can be used.

Further, the toner base particles 11 may contain components other than those described above. Examples of such components include waxes, charge control agents, magnetic powders, and the like.
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. Examples of the synthetic ester wax include WEP-5 and WEP-7 (manufactured by NOF Corporation). Among these, one kind or a combination of two or more kinds can be used.

  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 condensates, cyclic polysaccharides, trimethylethane compounds, catechol metal salts, nigrosine compounds, tetraphenylborate derivatives, quaternary ammonium salts, onium compounds, toniphenylmethane compounds, alkylpyridinium salts, chlorination Examples 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 toner base particles 11 is, for example, metal oxide such as zinc oxide, cerium oxide, silica, titanium oxide, iron oxide, fatty acid, zinc stearate. Fatty acid metal salts such as may be used.

[External additive]
As described above, in the toner particles 1, the external additive 12 exists near the surface of the toner base particles 11. In particular, the external additive 12 is unevenly distributed near the constricted portion 113.
The external additive 12 has, for example, functions such as improving the durability of the toner particles 1 as a whole, controlling charging properties, improving fluidity, improving environmental stability, and improving cleaning properties.

  Examples of the external additive 12 include metal oxides such as silica, aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, titania, zinc oxide, and magnetite, nitrides such as silicon nitride, and carbonization. Fine particles composed of inorganic materials such as carbides such as silicon, calcium sulfate, calcium carbonate, aliphatic metal salts, fine particles composed of organic materials such as acrylic resin, fluororesin, polystyrene resin, polyester resin, aliphatic metal salt And fine particles composed of these composites and the like, and one or two or more selected from these can be used in combination. Further, as the external additive 12, the surface of the fine particles as described above is subjected to surface treatment with HMDS, a silane coupling agent, a titanate coupling agent, a fluorine-containing silane coupling agent, silicone oil, or the like. May be used.

The average particle size of the external additive 12 is preferably 10 to 500 nm, and more preferably 20 to 300 nm. As a result, the function of the external additive 12 can be more effectively exhibited while the external additive 12 is reliably held near the surface of the toner base particles 11.
The content of the external additive 12 with respect to 100 parts by weight of the toner base particles 11 is preferably 1.0 to 5.0 parts by weight, and more preferably 1.5 to 3.5 parts by weight. preferable. Thereby, the function of the external additive 12 can be exhibited more effectively while preventing the liberated external additive 12 from being excessively generated.

  The ratio of the external additive 12 contained in the toner that is free from the toner base particles 11 (free external additive) is, for example, a value measured using PT1000 (manufactured by Yokogawa Electric Corporation). be able to. This device burns toner particles in plasma, and measures the time difference between the emission peak of carbon atoms in the toner base particles and the emission peak of a specific metal element (for example, Si in the case of silica) used as an external additive. In the case of simultaneous light emission, it is determined that there is adhesion, and if there is a time difference, it is determined that the light is free. This ratio is preferably 5% by number or less, and more preferably 3% by number or less. Thereby, the effect by this invention as mentioned above is exhibited more notably.

The toner of the present invention as described above 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.
The toner particles as described above can be easily and reliably obtained by the method described below.

<Toner production method>
Next, a preferred embodiment of the toner manufacturing method as described above will be described. The toner production method of the present invention comprises the following steps.
(1) Colored resin solution preparation step In this step, a colored resin solution is obtained by dissolving or dispersing the binder resin, wax and colorant containing the polyester resin of the present invention in an organic solvent.
(2) Emulsion suspension preparation step In this step, a basic compound and water are sequentially added to the colored resin solution to emulsify and suspend the colored resin solution in an aqueous medium.

(3) Colored resin fine particle dispersion preparation step In this step, an aqueous electrolyte solution is added to the prepared emulsion suspension, and the dispersoids in the emulsion suspension are combined to produce colored resin fine particles.
(4) Coalescence Step An aqueous electrolyte solution is added to the colored resin fine particle dispersion, and a plurality of dispersoids (colored resin fine particles) are coalesced to form particles. This is a step of obtaining a dispersion.

(5) Solvent removal step In this step, the organic solvent is removed under reduced pressure.
(6) Separation / Washing Step In this step, the colored resin fine particles are separated and washed from the aqueous medium.
(7) Drying step In this step, the toner base particles 11 are dried.
(8) External Addition Step In this step, the external additive 12 is applied to the toner base particles 11.

[Colored resin solution preparation process]
In the colored resin solution preparation step, first, a binder resin containing the polyester resin of the present invention, a wax and a colorant are introduced into an organic solvent and dissolved or dispersed.
The binder resin, wax and colorant containing the polyester resin of the present invention are preferably dissolved or dispersed in an organic solvent with a high-speed stirrer. In this case, the colorant may be pre-dispersed in advance to prepare a master kneading chip and finely dispersed below the toner particle diameter to be produced. The wax may also be mixed after preparing the master kneading chip in advance. Alternatively, a wax master solution finely dispersed below the toner particle size by wet dispersion using media may be used.
As an organic solvent, the solubility in 100 parts by weight of water at 25 ° C. is preferably 30 parts by weight or less, and more preferably 25 parts by weight or less.
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. These organic solvents can be used in combination of two or more, but from the viewpoint of solvent recovery, it is preferable to use the same type of solvent alone. In addition, the organic solvent is preferably one having a low boiling point because it dissolves or disperses the polyester resin and is easy to remove the solvent in a later step. Here, as the organic solvent for dissolving the polyester resin, it is preferable to use methyl ethyl ketone and ethyl acetate, which are excellent in solubility and dispersibility. In particular, it is preferable to use methyl ethyl ketone.

Examples of the stirrer that can be used for the preparation of the colored resin solution include DESPA (manufactured by Asada Tekko Co., Ltd.), T.C. K. ROBOMIX (Primics Co., Ltd .: TK homodisper 2.5 wing) and the like.
The blade tip speed at the time of mixing using a stirrer is, for example, preferably 4 to 30 m / second, and more preferably 8 to 25 m / second. When the blade tip speed is a value within the above range, the resin component can be efficiently dissolved and dispersed in the organic solvent, and the colorant is dispersed more uniformly in the colored resin solution. It can be. On the other hand, if the blade tip speed is less than the lower limit, depending on the resin component, the colorant, the composition of the organic solvent, etc., the fine dispersion of the colorant in the colored resin solution may be insufficient. 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 solution, the resin component, the colorant, and the wax are dissolved or dispersed in the organic solvent.
The ratio of the solid content and the organic solvent in the colored resin solution is not particularly limited, but the organic solvent is preferably 33 to 100 parts by weight and 40 to 82 parts by weight with respect to 100 parts by weight of the solids. Is more preferable. If the organic solvent ratio is low, the viscosity is high, stirring becomes difficult, and the dissolution or dispersion of the resin component, colorant, and wax becomes poor. Further, when the ratio of the organic solvent is increased, the viscosity is decreased and the resin component is easily dissolved. However, there is a possibility that the colorant and the wax are not sufficiently dispersed without shearing. In addition, the total amount is increased and productivity is decreased.
The colored resin solution may contain an emulsifier (dispersant). Thereby, the dispersibility of the dispersoid (colored resin fine particles) in the colored resin fine particle dispersion 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. In the present invention, 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 Nonionic emulsifiers such as alkyl ethers, polyoxyethylene 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, Examples include cationic emulsifiers such as quaternary ammonium 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 (colored resin fine particles) in the colored resin fine particle dispersion is particularly excellent, and even when the emulsifier remains in the final toner, the charging characteristics of the toner particles are improved. In addition to being able to effectively prevent adverse effects, it is possible to effectively prevent an increase in the amount of VOC (volatile organic compound). 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 alkylbenzene sulfonate is preferably dodecylbenzene sulfonate. As a result, the dispersibility of the dispersoid (colored resin fine particles) in the colored resin fine particle dispersion is further improved, and even when the emulsifier remains in the final toner, the charging characteristics of the toner particles are improved. On the other hand, it is possible to more effectively prevent adverse effects and to more effectively prevent an increase in the amount of VOC (volatile organic compound).
The colored resin solution may contain the wax, the charge control agent, the magnetic powder and the like as described above as components other than the resin component, the colorant, and the organic solvent.

  In the preparation of the colored resin solution, all the components of the colored resin solution to be prepared may be mixed at the same time, or a part of the components of the colored resin solution to be prepared may be mixed in advance. Master) and then the mixture (master) may be mixed with other ingredients. For example, a colorant and a resin component are mixed (kneaded) to obtain a colorant master, and then the colorant master, the resin component (additional resin), and an organic solvent are mixed to prepare a color resin solution. It may be prepared. Thereby, the colored resin solution in which each component is uniformly mixed can be obtained more reliably. In addition, when using wax as a constituent component of the colored resin solution, for example, a material containing wax, water, an organic solvent, a resin component, and an organic solvent is mixed to obtain a wax master. A colored resin solution may be prepared by mixing with a colorant master, a resin component (additional resin), and an organic solvent. Thereby, a colored resin solution in which wax particles are finely dispersed can be obtained. In such a case, an emulsifier may be used for preparing the wax master. Thereby, the dispersibility of the wax particles in the wax master, the colored resin solution, etc. can be made particularly excellent. As the emulsifier, those described above can be used, and among them, alkylbenzene sulfonate is preferable, and dodecylbenzene sulfonate is more preferable. By using such an emulsifier, the dispersibility of the wax particles in the wax master, the colored resin solution, etc. can be further improved, and the variation in the size of the finely dispersed wax particles can be made particularly small. it can.

[Emulsion suspension preparation process]
In the emulsified suspension preparation step, a basic compound and water are sequentially added to the colored resin solution, and the colored resin solution is emulsified and suspended in an aqueous medium.
Here, it is preferable to gradually add water to the colored resin solution in which the carboxyl group of the polyester resin which is the resin component of the toner of the present invention is neutralized with the basic compound. By neutralizing the carboxyl group, the hydrophilicity of the polyester resin, which is the resin component of the toner of the present invention, is improved, and the affinity with water is improved.

  The added water is hydrated to the carboxyl group portion of the polyester resin, and the binder resin containing the polyester resin of the present invention is finely dispersed in combination with the stirring effect. On the other hand, the viscosity of the system containing the colored resin solution increases with the addition of water. When a certain amount of water is added, there is a point that the viscosity decreases, which is called a so-called phase inversion point. The viscosity increases until just before this, and the viscosity reaches the maximum value. The increase in viscosity correlates with the addition amount of the basic compound, and the increase in viscosity increases as the addition amount increases.

  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 solution prepared as described above, the colored resin solution (colored resin solution 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 solution and the aqueous medium.

Examples of the basic compound (neutralizing agent) include inorganic salts such as sodium hydroxide, potassium hydroxide and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine, and one kind selected from these. Alternatively, two or more kinds can be used in combination. The neutralizing agent may be an aqueous solution containing the above compound.
Moreover, the usage-amount of a basic compound has the preferable amount (1-3 equivalent) equivalent to 1-3 times of the amount required in order to neutralize all the carboxyl groups which a polyester resin has, and is equivalent to 1-2 times. The amount (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.

  The ratio of the organic solvent to the total amount of the organic solvent and water after the emulsification step is preferably in the range of 20 to 35 wt%, and more preferably in the range of 20 to 30 wt%. As described above, the amount of water up to the phase inversion point decreases as the amount of organic solvent in the colored resin solution preparation step decreases, and increases as the amount of basic compound increases. At the phase inversion point, the viscosity of the emulsified suspension may be high, and the colored resin solution may not be completely finely dispersed in the aqueous medium. Therefore, it is preferable to add water.

  The mixing of the colored resin solution and the aqueous medium may be performed by any method, but the aqueous medium is gradually added (dropped) to the colored resin solution while shearing the colored resin solution with a stirrer or the like. It is preferable to finally obtain a dispersion in which the dispersoid derived from the colored resin solution 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 high speeds such as DESPA (manufactured by Asada Tekko Co., Ltd.), homomixer (manufactured by Primix Co., Ltd.), slasher (manufactured by Mitsui Mining Co., Ltd.), and Cavitron (manufactured by Eurotech) A stirrer, a high-speed disperser, etc. are mentioned.
The blade tip speed at the time of mixing using a stirrer is, for example, preferably 4 to 30 m / second, and more preferably 8 to 25 m / second. 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 above upper limit, during mixing, the mixture of the colored resin solution and the aqueous medium may be scattered violently 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.

[Colored resin fine particle dispersion preparation step (colored resin fine particle production step)]
The dispersoid (colored resin fine particles) in the colored resin fine particle dispersion prepared in this step corresponds to the fine particles 111 constituting the toner base particles 11.
By adding the electrolyte to the emulsified suspension obtained above while stirring, the dispersoid in the emulsified suspension is salted out or destabilized. At this time, by stirring the emulsified suspension, the dispersoids collide with each other to be integrated. Finely dispersed resin oil droplets, wax dispersoids, colorant dispersoids and the like that are dispersoids are integrated into colored resin fine particles. Thereafter, the colored resin fine particles collide with each other, coalescence proceeds, and larger colored resin fine particles are generated. Thereby, the colored resin fine particles become particles having almost the same composition. By controlling the speed of the coalescence, colored resin fine particles having a desired size and particle size distribution (size corresponding to the fine particles 111) can be obtained.

  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 6.0 parts by weight with respect to 100 parts by weight of the solid content of the mixture of the colored resin solution and the aqueous medium. More preferably, it is 0.3 to 5.3 parts by weight. Moreover, 1-15 wt% is preferable and, as for the density | concentration of electrolyte solution, it is more preferable that it is 3-10 wt%. If the concentration is too low, the effect of the electrolyte is not sufficiently exhibited, and a large amount of electrolyte is required for salting out and coalescence. On the other hand, if the concentration is too high, unevenness tends to occur in the system, and aggregates and coarse particles are likely to be generated.
The electrolyte is preferably added in the form of an aqueous solution. As a result, the electrolyte can be quickly diffused throughout the liquid mixture, and the amount of electrolyte added can be easily and reliably controlled.

  When an electrolyte is added in this step, the electrolyte is preferably added while stirring with a stirring blade. Examples of the stirring blade used in this step include an anchor blade, a turbine blade, a fiddler blade, a full zone blade, a max blend blade, and a half moon blade. Of these, a max blend blade and a full zone blade are preferable. Thereby, the colored resin fine particles can be formed with a particularly small variation in size and composition among the particles.

The blade tip speed of the stirring blade is, for example, preferably 0.2 to 10 m / second, more preferably 0.2 to 8 m / second, and further preferably 0.3 to 6 m / second. . When the blade tip speed is a value within the above range, the colored resin fine particles can be formed with particularly small variations in size and composition among the particles.
Moreover, 10-50 degreeC is preferable, as for the material temperature at the time of stirring with a stirring blade, it is more preferable that it is 20-40 degreeC, and it is especially preferable that it is 20-35 degreeC.

[Joint process]
Next, a plurality of dispersoids (size corresponding to the colored resin fine particles) are combined to obtain combined particles. The obtained coalesced particles correspond to the toner base particles 11 to be manufactured. The coalescence of the dispersoid (colored resin fine particles) usually proceeds by fusing the aqueous electrolyte solution dropwise and colliding with the dispersoid containing the organic solvent in the same manner as the colored resin fine particle dispersion preparation step.

A method for uniting a plurality of dispersoids (colored resin fine particles) is not particularly limited, but a method of adding and adjusting an electrolyte in the dispersion is preferable. Thereby, coalesced particles can be obtained easily and reliably. Moreover, the particle size of the coalesced particles can be controlled easily and reliably by adjusting the amount of electrolyte added.
The amount of the electrolyte used in the coalescence process is preferably 0.5 to 15 wt%, more preferably 1 to 12 wt%, and particularly preferably 1 to 6 wt% with respect to the solid content. If the amount of electrolyte is too small, coalescence does not proceed sufficiently. If the amount of the electrolyte is too large, a large amount of stop water for the post-process is required, and it takes a long time for washing and drying.

  Moreover, 1-15 wt% is preferable and, as for the density | concentration of electrolyte solution, it is more preferable that it is 3-10 wt%. If the concentration of the electrolyte solution is too low, the effect of the electrolyte is not sufficiently exhibited, and a large amount of electrolyte is required for salting out and coalescence, which is not preferable. Or, colored resin fine particles may not be generated. On the other hand, if the concentration of the electrolyte solution is too high, unevenness is likely to occur in the system, and in particular, aggregates and coarse particles are likely to be generated during the formation of colored resin fine particles in the initial stage of coalescence, which is not preferable.

The treatment temperature in this step is preferably 10 to 50 ° C, more preferably 15 to 40 ° C, and further preferably 20 to 35 ° C. 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.
The blade tip speed of the stirring blade in this step is preferably smaller than the blade stirring speed in the colored resin fine particle dispersion preparation described above, and is 30 to 80% of the blade stirring speed in the colored resin fine particle dispersion preparation. It is preferable that it is 35 to 70%. Thereby, it is possible to more reliably prevent the once formed coalesced particles from collapsing while more efficiently coalescing the dispersoid (colored resin fine particles). As a result, coalesced particles with particularly small variations in shape and particle size among the particles can be obtained efficiently.

  The specific value of the blade tip speed of the stirring blade in this step is, for example, preferably 0.1 to 8 m / second, more preferably 0.2 to 6.5 m / second, More preferably, it is -5 m / sec. 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 (colored resin fine particles). 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. Thereby, coalescence of dispersoids (colored resin fine particles) 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.

[Desolvation (desolvation) step]
Thereafter, the organic solvent contained in the dispersion is removed (desolvent process). As a result, a dispersion of toner base particles 11 is 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 materials such as the resin component.

The treatment temperature in this step is preferably lower than the glass transition point (Tg) of the resin component constituting the toner base particles 11. The coalesced particles encapsulate an organic solvent together with the aqueous medium and swell, and therefore easily aggregate under high temperature conditions.
Therefore, it is preferable to carry out the desolvation under reduced pressure in order to carry out the desolvation quickly under a low temperature condition. In removing the solvent, an antifoaming agent is preferably added.

Examples of antifoaming agents include 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, and phosphoric acid. Esters can be used. Particularly preferred is a silicone emulsion. Examples of the silicone-based antifoaming agent include BY22-517, SH5503, SM5572F, BY28-503 (manufactured by Toray Dowco Ichining Silicone), KM75, KM89, KM98, KS604, KS538 (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. is there. Especially, BY22-517 is preferable as a thing with little influence on a physical property and a high defoaming effect.
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.

[Separation / washing process]
Next, the toner base particles 11 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 base particles 11 are separated by solid-liquid separation (separation from an aqueous medium), and then the solid content (toner) is redispersed in water and solid-liquid separation (toner mother from an aqueous medium) is performed. By separating the particles 11). The redispersion of solid content (toner) in water and solid-liquid separation may be repeated a plurality of times. Separation from the aqueous medium can be performed by a centrifugal separator, or a separation means such as a filter press or a belt filter.

[Drying process]
Then, a drying process is performed (drying process). As a result, the amount of water in the final toner can be made low, and the charging characteristics, stability, reliability, etc. of the toner can be made particularly excellent.
The drying process is, for example, a vacuum dryer using a freeze dryer, a ribocorn type dryer (Okawara Seisakusho), a mixed vacuum dryer such as a Nauta mixer (Hosokawa Micron), a fluidized bed dryer (Okawara Seisakusho), or a vibrating fluidized bed dryer. It is dried with a fluidized bed dryer such as (Chuo Chemical).
The treatment temperature in this step is preferably lower than the glass transition point (Tg) of the resin component constituting the toner base particles 11.

[External addition process]
Thereafter, the external additive 12 is applied to the toner base particles 11 by an external addition process (external addition step). Thereby, a final toner is obtained.
The external addition treatment may be performed by any method, but the external additive 12 is efficiently removed in the vicinity of the constricted portion 113 while effectively preventing deformation (including aggregation, decomposition, etc.) of the toner base particles 11. Therefore, it is preferable to carry out the following method.

In the present embodiment, the external addition process is performed using an external addition treatment tank as shown in FIGS.
As shown in FIG. 3, the external addition processing tank E1 has a horizontal disk-shaped tank bottom E2 and a drive shaft E3 penetrating vertically through the center of the tank bottom E2, and the drive shaft E3 includes a stirring blade ( Turbine blades E5 are attached. The stirring blade E5 is provided with a donut-shaped disc E4 for reinforcement and securing of a flow path at the upper part thereof.

  In this step, the toner base particles 11 and the external additive 12 which are the objects to be processed are released upward along the inner wall of the external treatment tank E1 by the centrifugal force of the stirring blade E5. A cylindrical member E7 is arranged inside the external treatment tank E1, and the object to be processed released by the stirring blade E5 is received by the outer wall surface of the cylindrical member E7 and then dropped. The object to be treated is re-supplied to the stirring blade E5 from between the center hole of the donut-shaped disk E4 and the drive shaft E3, and dispersion mixing proceeds by repeating the above.

  Further, the external addition processing tank E1 has a spherical shape having a horizontal tank bottom E2, and is provided with a flange E8 at the center so as to be divided into two vertically, and the entire spherical part is provided with a jacket E9. A heavy structure is used, and a heat medium is allowed to flow to heat or cool the workpiece. A cylindrical member E7 that also serves as an input hole for an object to be processed is provided in the upper part of the external addition processing tank E1, and a discharge port for toner particles 1 as an object to be processed after the external addition is provided in the lower part. (Not shown) is provided as appropriate.

  As described above, the stirring blade E5 is attached to the drive shaft E3 in the vicinity of the bottom of the tank so as to be rotatable by external power, and the tip of the driving shaft E3 has an outer periphery of the donut-shaped disk E4 and a tank wall as shown in FIGS. It arrange | positions so that it may be located between. Further, as shown in FIG. 3, the lower edge of the stirring blade E5 has an arc shape along the spherical inner wall of the external addition processing tank E1, and the object to be processed is rotated as indicated by the arrow by rotating. It is set as the shape which can discharge | release toward the top part of an external addition processing tank along the curved surface of an inner surface. The seal air hole E6 is an air supply hole for preventing the object to be processed from being welded to the drive shaft portion that is at a high temperature, and the supplied air is discharged from the cylindrical member E7.

  From the viewpoint of uniform processability of the workpiece and the ability to discharge the supplied air, the length of the cylindrical member E7 inside the container is 1/20 or more of the height from the donut disk E4 inside the container. The length is preferable, and the length is more preferably 1/3 or more. In addition, the upper limit of the length of the cylindrical member E7 inside the container is preferably set to a length that does not contact the powder surface when the object to be processed is left standing. Further, the cylindrical member E7 may have a structure other than the cylindrical shape as long as the seal air can escape, and may have a structure having a slit, for example.

Moreover, it is preferable that ratio of the diameter of the horizontal tank bottom E2 and the diameter of the external treatment tank E1 is 0.25-0.80. As a result, the external additive 12 can be efficiently distributed in the vicinity of the constricted portion 113 while effectively preventing the deformation of the toner base particles 11.
Moreover, it is preferable that ratio of the outer diameter of donut-shaped disk E4 and the diameter of horizontal tank bottom E2 is 0.50-1.20. Thus, the external additive 12 can be unevenly distributed in the vicinity of the constricted portion 113 while effectively preventing the deformation of the toner base particles 11.

Moreover, it is preferable that ratio of the diameter of the stirring blade E5 and the diameter of the external addition processing tank E1 is 0.50-0.90. Thus, the external additive 12 can be unevenly distributed in the vicinity of the constricted portion 113 while effectively preventing the deformation of the toner base particles 11.
The ratio of the inner diameter to the outer diameter of the donut disk E4 is preferably 0.5 to 0.95, and more preferably 0.7 to 0.8. Thus, the external additive 12 can be unevenly distributed in the vicinity of the constricted portion 113 while effectively preventing the deformation of the toner base particles 11.

Further, the amount of the object to be processed in the external addition treatment tank E1 is preferably 0.1 to 0.9, more preferably 0.3 to 0.5, as a ratio to the volume of the treatment tank. preferable. Thus, the external additive 12 can be unevenly distributed in the vicinity of the constricted portion 113 while effectively preventing the deformation of the toner base particles 11.
Further, the peripheral speed (π × outermost diameter of blade × rotational speed / hour) of the stirring blade E5 is preferably 20 to 100 m / sec, and more preferably 40 to 70 m / sec. Thus, the external additive 12 can be unevenly distributed in the vicinity of the constricted portion 113 while effectively preventing the deformation of the toner base particles 11.
Moreover, it is preferable that mixing processing time is 0.5 to 10 minutes, and it is more preferable that it is 1 to 5 minutes. Thus, the external additive 12 can be unevenly distributed in the vicinity of the constricted portion 113 while effectively preventing the deformation of the toner base particles 11.

  Further, in order to avoid the temperature rise or to fully exhibit the function of the external additive, a plurality of external additives may be mixed in a plurality of times in order to define the adhesion order. In such a case, it is desirable that the time for one mixing process be in the above-described range. Note that if the peripheral speed is too slow or the mixing process time is too short in the mixing process of the toner base particles 11 and the external additive 12, the mixing process may be insufficient. On the other hand, if the peripheral speed is too fast or the mixing treatment time is too long, welding may occur and the yield may decrease.

  In the external addition processing tank E1, the rapid rise of the object to be processed can be eliminated as compared with a conventionally widely used mixing apparatus such as a Henschel mixer. The external additive 12 can flow at a high speed along the curved tank wall, and the wall surface distance through which the material to be processed flows is long, so that the toner base particles 11 are easy to roll and can be uniformly removed in a short time. Attaching is possible. Further, while effectively preventing the deformation of the toner base particles 11, it is possible to make the external additive 12 adhere to the whole and to be unevenly distributed in the vicinity of the constricted portion 113. Furthermore, after moving the object to be processed to the ceiling of the external treatment tank, it is supplied to the stirring blades at the bottom of the tank and reprocessed, so that the vertical movement of the object to be processed that depends on gravity is a cylindrical mixing device Compared to the above, there is an advantage that it becomes more dynamic and there is no need to provide an upper blade. Moreover, you may provide a convex part in a tank and generate | occur | produce a turbulent flow. Thereby, aggregation of the external additive 12 can be prevented more reliably.

<Image forming apparatus>
Next, an image forming apparatus to which the toner of the present invention described above is applied will be described.
5 is an overall configuration diagram showing a preferred embodiment of an image forming apparatus to which the toner of the present invention is applied, FIG. 6 is a cross-sectional view of a developing device included in the image forming apparatus of FIG. 5, and FIG. FIG. 8 is a perspective view illustrating 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. 6, 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. 5, 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 shaft of the fixing roller 210 and the pressure roller 220 is connected to 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. 7, 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. 8, 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.

  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. 7 and 8, 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 this embodiment, as shown in FIGS. 7 and 8, 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 present invention, the toner particles may have a so-called core-shell structure having a core region (core portion) and a shell region (outer shell) covering the core region. In such a case, the core region may be formed by combining a plurality of fine particles.

In addition, the toner of the present invention may be a toner base particle in which a plurality of fine particles are bonded together and has a constricted portion at the outer peripheral portion of the bonding surface of the fine particles. It may contain fine particles (fine particles that are not bonded). In such a case, the ratio of the toner base particles composed of a single fine particle to the whole toner base particles is preferably 50% by number or less, and more preferably 30% by number or less. Thereby, the effects as described above are sufficiently exhibited.
Further, the toner of the present invention may be produced by any method, and the above-described methods (including the colored resin solution preparation step, the emulsion suspension preparation step, and the colored resin fine particle dispersion preparation step are combined. The method is not limited to those produced by a method having a step, a solvent removal step, a washing step, a drying step, and an external addition step.
Further, the toner of the present invention may be any toner that has toner base particles having a constricted portion as a main component, and may include toner base particles that do not have a constricted portion, for example. In such a case, the ratio of the toner base particles having a constricted portion to the entire toner base particles is preferably 50% by number or more, more preferably 80% by number or more, and 90% by number or more. Is more preferable.

[1] Toner Production Prior to toner production, resins (resin R-1 and resin R-2) are synthesized, and further, a wax master (wax master 1) and a colorant master are synthesized using the synthesized resins. (Colorant master C, colorant master M, colorant master Y) and colored resin solutions (colored resin solution MB-1 and colored resin solution MB-2) were prepared.

<Synthesis of Resin R-1>
Terephthalic acid: 221 parts by weight Isophthalic acid: 95 parts by weight Neopentyl glycol: 104 parts by weight Ethylene glycol: 62 parts by weight Tetrabutyl titanate: 2.5 parts by weight Epicron 830: 7.0 parts by weight Cardura E: 3.0 parts by weight

  The above raw materials were put into a glass 2 L four-necked flask, a thermometer, a stirring rod and a nitrogen introducing tube were attached, and the reaction was carried out in an electric heating mantle heater at 240 ° C. for 10 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 temperature specified in ASTM E28-517, and the reaction was terminated when the softening point reached 160 ° C. The obtained polymer was a colorless solid having an oxidation of 11.0 KOH mg / g, a glass transition temperature of 64 ° C. by a DSC measurement method, and a softening temperature (T1 / 2) by a flow tester of 175 ° C. However, “Epiclon 830” is a bisphenol F type epoxy resin manufactured by Dainippon Ink and Chemicals, Inc., and its epoxy equivalent is 170 g / eq (hereinafter the same). “Cardura E” is an alkyl glycidyl ester manufactured by Shell Japan, and its epoxy equivalent is 250 g / eq (hereinafter the same).

<Synthesis of Resin R-2>
Terephthalic acid: 315 parts by weight Neopentyl glycol: 21 parts by weight Ethylene glycol: 12 parts by weight Propylene glycol: 122 parts by weight Tetrabutyl titanate: 2.5 parts by weight

  The above raw materials were put into a glass 2 L four-necked flask, a thermometer, a stirring rod and a nitrogen introducing tube were attached, and the reaction was performed at 240 ° C. for 12 hours in an electric heating mantle heater under a normal pressure nitrogen stream. . Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The acid value was measured on the way, and isophthalic acid was added until the oxidation reached the target value to adjust the resin acid value. The reaction was followed by the softening temperature specified in ASTM E28-517, and the reaction was terminated when the softening point reached 100 ° C. The obtained polymer was a colorless solid having an oxidation of 10.0 KOH mg / g, a glass transition temperature of 57 ° C. by DSC measurement, and a softening temperature (T1 / 2) of 102 ° C. by a flow tester.

<Preparation of wax master WM-1>
High-speed emulsifier K. To a 3 L cylindrical container attached to Robomix (Primics Co., Ltd., TK Homomixa MARKII2.5 type), water: 1300 parts by weight, sodium dodecylbenzenesulfonate as an emulsifier: 25.7 parts by weight, 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, the high-speed disperser T.P. K. Into 3L cylindrical container attached to Robomix (Primics Co., Ltd., TK Homodisper 2.5 wing), 856 parts by weight of methyl ethyl ketone was charged, and 700 parts by weight of resin R-2 was gradually added with stirring. Then, after confirming that the resin R-2 was uniformly dissolved, the first wax dispersion: 878.6 parts by weight was added to prepare a premixed solution. Next, the preliminary mixed solution was mixed with a star mill (manufactured by Ashizawa Finetech Co., Ltd., LMZ-10) to obtain a wax master 1 having a solid content of 45.0 wt%. The composition of the obtained wax master 1 was resin R-2: wax: emulsifier: methyl ethyl ketone: water = 31.3: 13.4: 0.3: 29.5: 25.5 in a weight ratio.

<Preparation of Colorant Master PM-C>
Cyan pigment (Dainippon Ink & Chemicals, KET BLUE 111: CI Pigment B-15: 3): 2000 parts by weight and resin R-2: 2000 parts by weight, ST / A0 blade was set. The mixture was put into a 20 L Henschel mixer (Mitsui Mining Co., Ltd.) and stirred at a blade tip speed of 10 m / sec for 2 minutes 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-C. The composition of the coloring master C was, as a weight ratio, coloring agent: resin = 50: 50. Moreover, when the obtained colorant master PM-C was diluted with resin R-2 and methyl ethyl ketone, and observed with a 400 times optical microscope for the finely dispersed state of the colorant and the presence or absence of coarse particles, coarse particles were observed. However, it was observed that the powder was uniformly finely dispersed.

<Preparation of colorant master PM-M>
A magenta pigment (manufactured by Clariant Japan, Permanent Ruby F6B: CI Pigment R-184) was used instead of the cyan pigment, and mixing and kneading were performed in the same manner as the colorant master PM-C. A colorant master PM-M was obtained. In addition, the obtained colorant master PM-M was diluted with resin R-2 and methyl ethyl ketone, and when the finely dispersed state of the colorant and the presence or absence of coarse particles were observed with an optical microscope of 400 times, coarse particles were observed. However, it was observed that the powder was uniformly finely dispersed.

<Preparation of colorant master PM-Y>
Except for using a yellow pigment (Clariant Japan, Toner Yellow HG: CI Pigment Y-180) in place of the cyan pigment, mixing and kneading were performed in the same manner as the colorant master PM-C. A colorant master PM-Y was obtained. Further, the obtained colorant master PM-Y was diluted with resin R-2 and methyl ethyl ketone, and when the finely dispersed state of the colorant and the presence or absence of coarse particles were observed with a 400-fold optical microscope, coarse particles were observed. However, it was observed that the powder was uniformly finely dispersed.

<Preparation of colored resin solution MB-1>
High-speed disperser T. K. 95.5 parts by weight of methyl ethyl ketone (diluted methyl ethyl ketone) is charged into a 2 L cylindrical container (disper blade diameter 40 mm) attached to Robomix (Primix Co., Ltd., TK homodisper 2.5 blade), and resin R-1 (diluted resin): 99.6 parts by weight were added. In this state, stirring was performed at a blade tip speed of 7.5 m / sec. With stirring, colorant master PM-C: 42 parts by weight, resin R-2 (diluted resin): 58.4 parts by weight, wax master WM-1: 223.9 parts by weight, and dodecylbenzene as an emulsifier By adding 1.1 parts by weight of sodium sulfonate in this order into the cylindrical container, each component was dissolved and dispersed. Furthermore, after that, methyl ethyl ketone was additionally added so that the solid content was 65 wt% to obtain a colored resin solution MB-1. In addition, the material temperature at the time of stirring was kept at 30-40 degreeC.

(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).
<< Emulsion suspension preparation process >>
After adding 1N ammonia water: 50 parts by weight to the colored resin solution (mill base) MB-1: 520.5 parts by weight (solid content: 300 parts by weight) and stirring at a blade tip speed: 7.5 m / sec. The temperature was adjusted to 35 ° C.

  Thereafter, the blade tip speed was changed to 14.7 m / sec. In this state, 316.6 parts by weight of water (deionized water) was added dropwise at a rate of 20 parts by weight / min to prepare a dispersion. 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). Thereafter, a predetermined amount of remaining deionized water was added dropwise to obtain an emulsified suspension. The content of methyl ethyl ketone (organic solvent) in the dispersion at this stage was 27.6 wt%. In this dispersion, coarse particles having poor dispersibility were not observed.

<< Colored resin fine particle preparation process: Colored resin fine particle preparation process >>
Next, particles of the dispersoid were grown by adding an electrolyte to the emulsified suspension. That is, by adding an electrolyte, a plurality of types of dispersoids having different compositions (a resin dispersoid whose main component is a solid component, a colorant dispersoid whose main component is a colorant, a solid component Wax dispersoid whose main component is wax was integrated to form colored resin fine particles. The electrolyte was added as follows.

First, a Max Blend blade (blade diameter: 65 mm) was attached to a 2 L cylindrical container containing the emulsified suspension, and the temperature was adjusted to 25 ° C. while maintaining the blade tip speed: 0.85 m / second.
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% sodium sulfate aqueous solution (first stage electrolyte) was added dropwise at 10 parts by weight / min. After completion of dropping, the blade tip speed was adjusted to 0.54 m / sec, and stirring was continued until the particle size of the dispersoid (colored resin fine particles) became 3.2 μm. When the particle size of the dispersoid reaches 3.2 μm, the blade tip speed of the Max Blend blade is adjusted to 1.53 m / second, and a 5.0 wt% sodium sulfate aqueous solution (second stage electrolyte): 20 parts by weight Was added dropwise at 10 parts by weight / min. After completion of dropping, the blade tip speed was adjusted to 0.54 m / sec, and stirring was continued until the particle size of the dispersoid (colored resin fine particles) reached 5.5 μm. When the particle size of the dispersoid reaches 5.5 μm, the blade tip speed is maintained at 1.53 m / sec for 30 minutes, the particle size distribution and shape of the dispersoid (colored resin fine particles) are adjusted, and the colored resin fine particles are dispersed. A colored resin fine particle dispersion was obtained. The colored resin fine particles formed by the treatment as described above were incorporated in a state where pigment fine particles and wax fine particles were finely dispersed.

<< Unification process: Unification particle preparation process >>
In a 2 L cylindrical container in which the colored resin fine particles were prepared, 50 parts by weight of deionized water was added, and the tip speed of the Max Blend blade was adjusted to 1.53 m / sec. Sodium aqueous solution: 20 parts by weight was added dropwise at 10 parts by weight, and after completion of the addition, the blade tip speed was reduced to 0.34 m / s and stirring was further continued for 10 minutes. Here, this dispersion was observed. As a result, a large number of coalesced particles in which a plurality of colored resin fine particles were united were confirmed. Thereafter, water (deionized water): 500 parts by weight is added, and stirring is performed in a state where the blade tip speed is adjusted to 0.54 m / sec. A dispersion liquid was obtained. At this time, the 50% volume particle size was 8.0 μm.

<< Solvent removal process >>
Thereafter, a silicone-based antifoaming agent (manufactured by Toray Dow Corning Silicone, BY22-517): 0.05 parts by weight is diluted with 30 parts by weight of deionized water, and the solid content is 23 wt. Methyl ethyl ketone and a part of water were distilled off until it became at least% to obtain a slurry (colored resin fine particle slurry).
《Separation / washing 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 colored resin fine particle cake of colored resin fine particles was obtained by a suction filtration method.

<< Drying process >>
Then, toner mother particles were obtained by drying the colored resin fine particle cake using a vacuum dryer. The obtained toner base particles have a configuration in which a plurality of fine particles (colored resin fine particles) are bonded and a constricted portion is provided on the outer peripheral portion of the bonding surface of the fine particles. In addition, the constricted portion of the toner base particles is provided over the entire circumference of the toner base particles with the normal line of the bonding surface of the fine particles as an axis. In addition, the center of gravity of the constricted portion substantially coincided with the center of gravity of the toner base particles (the distance between the center of gravity of the constricted portion and the center of gravity of the toner base particles is 0.1 μm or less). Further, Dv (50) (L ₀ ) when the 50% volume particle diameter of the toner base particles is Dv (50) [μm] and the 50% number particle diameter is Dn (50) [μm] is 7 0.0 μm and Dv (50) / Dn (50) were 1.10.
The average particle diameter L ₁ of the fine particles constituting the toner mother particles was 5.0 .mu.m. Average length L ₂ of the joint surface of the fine particles in the projection shape of the toner mother particles was 3.5 [mu] m.
The particle size, particle size distribution and the like were measured with a Coulter Counter Multisizer II (manufactured by Beckman Coulter, Inc.) using a 100 μm aperture tube. The other particles described below were similarly measured for particle size and particle size distribution. The average circularity R of the toner base particles was 0.958. 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.

《External addition process》
To the toner base particles obtained as described above: 100 parts by weight of silica RX50 having an average particle size of 40 nm (large particle size silica: manufactured by Nippon Aerosil Co., Ltd.): 0 parts by weight, average particle diameter: 12 nm of silica RX200 (Small particle diameter silica: manufactured by Nippon Aerosil Co., Ltd.): 1.0 part by weight, put into the external processing apparatus shown in FIGS. Speed: mixed for 2 minutes at 40 m / sec, then, as the second stage, titanium oxide STT30S with an average particle diameter of 30 nm (titania: manufactured by Titanium Industry Co., Ltd.): 0.5 part by weight is added to the mother particles , Mixed at 50 m / sec for 2 minutes 30 seconds, and then added 0.5 parts by weight of silica NA50H (positively charged silica: manufactured by Nippon Aerosil Co., Ltd.) having an average particle size of 40 nm as the third stage. Mix for 2 minutes in seconds to make the final toner ( Antona) was obtained. In addition, the length inside the container of the cylindrical member E7 was 1/4 of the height from the donut-shaped disk E4 inside a container. Moreover, the ratio of the diameter of the horizontal tank bottom E2 and the diameter of the external treatment tank E1 was 0.70. Moreover, the ratio of the outer diameter of the donut-shaped disk E4 and the diameter of the horizontal tank bottom E2 was 0.85. Further, the ratio of the diameter of the stirring blade E5 to the diameter of the external treatment tank E1 was 0.70. The ratio of the inner diameter to the outer diameter of the donut disk E4 was 0.80. Moreover, the preparation amount of the to-be-processed object to the external addition processing tank E1 was 0.45 in ratio with respect to the volume of a processing tank.

As a result of SEM observation at a magnification of 10,000 times, the obtained toner was mostly composed of mother particles joined by two particles, and the external additive adhered almost uniformly and uniformly except the constricted part of the toner mother particles. However, many of the external additives adhered to the constricted portion, that is, the external additives were unevenly distributed in the constricted portion of the toner base particles.
In the obtained toner, the external additive (free external additive) released from the toner base particles was measured with a particle analyzer PT1000 (manufactured by Yokogawa Electric Corporation). The ratio of the free external additive was 1.7% for silica and 3.0% for titania. No change in the shape and size of the toner base particles due to the external addition treatment was observed.

In Table 1, the SEM observation at 10000 times observes 500 toners, and the ratio of one toner mother particle to which fine particles are not bonded is the R ₁ [number%] toner mother formed by bonding two fine particles. The ratio of the particles is R ₂ [number%], the ratio of the toner base particles formed by bonding three fine particles is R ₃ [number%], and the ratio of the toner base particles formed by bonding four or more fine particles is R _It was expressed as _m [number%].

(Example 2)
A colored resin solution and an emulsified suspension were prepared in the same manner as in Example 1, and the first-stage electrolyte was added dropwise, and stirring was continued until the thickness became 3.5 μm. In the next coalescence step, 50 parts by weight of deionized water was added and the tip speed of the Max Blend blade was adjusted to 1.53 m / sec. After dropping, the blade tip speed was reduced to 0.34 m / sec and stirring was continued for 10 minutes. Thereafter, 500 parts by weight of water (deionized water) was added, the blade tip speed was adjusted to 0.54 m / sec, and particle growth was stopped. Further, in the same manner as in Example 1, solvent removal, washing, and drying steps were performed to obtain toner mother particles. Many particles having a constricted portion having a 50% volume particle diameter of 4.9 μm and a circularity of 0.951 were confirmed.
Thereafter, an external addition process was performed in the same manner as in Example 1 to obtain a toner.

(Examples 3 to 10)
Table 1 shows the structure of the toner by adjusting the amount of aqueous sodium sulfate used in each step (colored resin fine particle dispersion preparation step and coalescence step), the stirring conditions in each step, and the amount of external additive added. A toner was manufactured in the same manner as in Example 1 except that the above was changed.
(Example 11)
A toner was produced in the same manner as in Example 2 except that Colorant Master M was used instead of Colorant Master C.
Example 12
A toner was produced in the same manner as in Example 2 except that Colorant Master Y was used instead of Colorant Master C.

(Comparative Example 1)
Resin R-1: 180 parts by weight, resin R-2: 235 parts by weight, colorant master PM-C: 70 parts by weight, and carnauba wax (manufactured by Nippon Wax Co., Ltd.): 15 parts by weight are mixed with a Henschel mixer. Then, it melt-kneaded with the biaxial extrusion kneader. The kneaded product was cooled to room temperature, coarsely crushed with a hammer mill, further finely pulverized with a jet mill, and classified with an air classifier to obtain toner base particles. The obtained toner base particles have an irregular shape (non-spherical shape). The toner base particles have a 50% volume particle diameter of Dv (50) [μm] and a 50% number particle diameter of Dn (50) [μm]. ], Dv (50) was 7.5 μm and Dv (50) / Dn (50) was 1.25. The average circularity R of the toner base particles was 0.931.

  The toner base particles obtained as described above were subjected to external addition treatment in the same manner as in Example 1 to obtain a toner. In the obtained toner particles, minute irregularities were provided in the vicinity of the surface of the toner base particles, but there was a large variation in the shape among the respective particles (toner base particles), and the base particles with little external additive adhesion. The mother particles with a large amount of external additives admixed therewith. In addition, mother particles with many irregularities and particle mother particles with almost no irregularities were mixed. Further, the variation in the depth of the unevenness between the particles (toner base particles) was also large.

(Comparative Example 2)
In the colored resin fine particle dispersion preparation step, the amount of electrolyte used and the blade tip speed were the same as in Example 1, and stirring was continued until the colored resin fine particles became 5.8 μm. Thereafter, the coalescence step was omitted, 500 parts by weight of deionized water was added, and the particle growth was stopped. Further, in the same manner as in Example 1, solvent removal, washing, and drying steps were performed to obtain toner mother particles. Most of the obtained toner base particles did not have a constricted portion. The 50% volume particle size of the toner base particles was 5.0 μm, and the circularity was 0.987. The toner base particles thus obtained did not have a constricted portion as the toner base particles in each example had.
Thereafter, the toner base particles obtained as described above were externally treated in the same manner as in Example 1 to obtain a toner.

Table 1 summarizes the main components of the toner, and Table 2 summarizes the external additive formulation. In Table 1, 500 toners were observed by SEM at 10,000 magnifications in Table 1 with respect to the whole toner base particles constituting the toner, and toner base particles to which fine particles were not bonded (from one fine particle). The ratio of the toner base particles is R ₁ [number%], and the ratio of the toner base particles formed by joining two fine particles is R ₂ [number%] of the toner base particles formed by joining three fine particles. The ratio was expressed as R ₃ [number%], and the ratio of toner base particles formed by joining four or more fine particles was expressed as R _m [number%]. Further, in the toners of Examples 1 to 12, the external additive was unevenly distributed in the constricted portion of the toner base particles. Further, the resin components constituting the toners of the examples and the comparative examples showed the same glass transition temperature, softening temperature and average molecular weight as the resin used as the raw material.

[2] Evaluation The following evaluation was performed on the toner obtained in each of the above Examples and Comparative Examples.
[2.1] Maintaining fluidity After the toner is filled in the housing of the developing device (see FIG. 6) of the image forming apparatus as shown in FIGS. 5 to 8, the recording medium (for a color laser printer manufactured by Seiko Epson Corporation) is used. On the coated paper A4), 3000 sheets of predetermined pattern printing (5% printing) were continuously performed. From the apparent density of the toner before printing (D ₀ [g / cm ³ ]) and the apparent density of the toner after printing 3000 sheets (D ₁ [g / cm ³ ]), the rate of decrease in the apparent density ([1- (D ₁ / D ₀ )] × 100) was determined and evaluated according to the following four-stage criteria. It can be said that the smaller the apparent density decrease rate, the more fluidity is maintained.
A: The apparent density decrease rate is less than 5%.
○: The decrease rate of the apparent density is 5% or more and less than 10%.
(Triangle | delta): The decreasing rate of an apparent density is 10% or more and less than 15%.
X: The decrease rate of the apparent density is 15% or more.

[2.2] Durability After the toner is filled into the housing of the developing device (see FIG. 6) of the image forming apparatus as shown in FIGS. 5 to 8, the recording medium (color laser printer coat, manufactured by Seiko Epson Corporation) On a paper A4), a predetermined pattern (5% printing) was continuously printed on 5000 sheets, and the occurrence of blurring in an image printed on a recording medium was confirmed, and evaluated according to the following five criteria.

A: Scratch is not observed in the 1st to 6000th printed matter.
A: Scratch is not observed on the 1st to 5000th printed matter, but scumming is observed on the 5001 to 6000th printed matter.
◯: Scratch is not observed on the 1st to 3000th printed matter, but scumming is observed on the 3001 to 5000th printed matter.
Δ: Scratch is not observed on the 1st to 2000th printed materials, but scum is observed on the 2001 to 3000th printed materials.
X: Scratch generation is observed in the printed matter of the 1st to 2000th sheets.

[2.3] Transfer Efficiency Toner was filled in the housing of the developing device (see FIG. 6) of the image forming apparatus as shown in FIGS. In this image forming apparatus, a solid image was formed and remained on the photosensitive drum immediately after the development process (before transfer) on the photosensitive drum (image carrier) and on the photosensitive drum after transfer (after printing). The toner was collected using separate tapes, and the weight of each was measured. When the toner weight on the photosensitive drum before transfer is W _b [g] and the toner weight on the photosensitive drum after transfer is W _a [g], it is obtained as (W _b −W _a ) × 100 / W _b. The value was determined as transfer efficiency. It can be said that the larger the numerical value, the better the transfer efficiency.

[2.4] Cleaning property After the toner is filled in the housing of the developing device (see FIG. 6) of the image forming apparatus as shown in FIGS. 5 to 8, continuous 6000 sheets printing (5% printing) is performed for cleaning. Sex was evaluated according to the following three-stage criteria.
○: No wiping residue on the surface of the intermediate transfer belt is observed.
Δ: In the initial stage of printing, almost no wiping residue on the surface of the intermediate transfer belt is observed, but the cleaning defect gradually increases, and when 5000 sheets are printed, an obvious cleaning defect is recognized.
X: A clear cleaning defect is recognized from the initial stage of printing.

[2.5] Cavity Using an image forming apparatus as shown in FIGS. 5 to 8, printing is performed on Epson coated paper from a horizontal 1-dot line to a 10-dot line. The presence or absence of voids in the vicinity was observed visually and with an optical microscope (× 100 magnification), and evaluated according to the following three-stage criteria.
○: No voids are observed visually and with a microscope.
Δ: No voids are observed by visual observation, but voids are observed by microscopic observation.
X: A void is observed by visual observation.
These results are shown in Table 3.

As is apparent from Table 3, the toner of the present invention effectively prevented a decrease in fluidity over time, and was able to maintain fluidity in a suitable manner. Further, the toner of the present invention was excellent in durability, transfer efficiency, and cleaning properties. From the above, it can be seen that the toner of the present invention exhibits the function of the external additive effectively.
On the other hand, satisfactory results were not obtained with the toners of the comparative examples.
More specifically, in the toner of Comparative Example 1 obtained by the pulverization method, fine irregularities were provided in the vicinity of the surface of the toner base particles, but the shape variation between the particles (toner base particles) was different. In addition, after the endurance test, the corners of the toner were removed and the amount of fine powder increased, which was not satisfactory.
Further, in the toner of Comparative Example 2 having no constricted portion, after the durability evaluation, the external additive is embedded in the toner base particles, and the external additive having a size of several μm, which seems to have been scraped off. Aggregation of the agent was observed, and the decrease in fluidity was remarkable. Further, in the toner of Comparative Example 2, the transfer efficiency was extremely lowered after the durability evaluation. Also, the cleaning property was very bad from the beginning. Further, in the toner of Comparative Example 2, aggregation of the external additive was remarkably observed, and a large amount of the external additive separated from the toner base particles was also observed. This is considered to be because in the toner of Comparative Example 2, since the external additive is not stably held at a specific portion of the toner base particles, the external additive tends to aggregate.

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. It is a center sectional view of an external addition processing device used in an external addition process. It is a top view which shows an example of the mixing blade | wing which the external addition processing apparatus shown in FIG. 3 has. 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. 6 is a cross-sectional view of a developing device included in the image forming apparatus of FIG. 5. FIG. 6 is a perspective view showing a detailed structure of a fixing device used in the image forming apparatus of FIG. It is principal part sectional drawing of the fixing device of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Toner particle 11 ... Toner mother particle 111 ... Fine particle 112 ... Joining surface 113 ... Constriction part 12 ... External additive E1 ... External addition processing tank E2 ... Horizontal disk-shaped tank bottom E3 ... Drive shaft E4 ... Donut-shaped disk E5: Stirrer blade (turbine blade) E6 ... Seal air hole E7 ... Cylindrical member that releases seal air E8 ... Flange E9 ... Jacket 10 ... Image forming device 20 ... Device 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 ... Cyan developing device 60K ... Developing device for black 70 ... Intermediate transfer device 90 ... Drive Roller 100 ... Follower roller 110 ... Intermediate transfer belt 120 ... Primary transfer roller 130 ... Transfer belt cleaner 140 ... Secondary transfer roller 150 ... Paper feed cassette 160 ... Pickup roller 170 ... Recording medium transport path 190 ... Fixing device 200 ... Paper discharge tray DESCRIPTION OF SYMBOLS 210 ... Fixing roller (heat fixing member) 210a ... Heat source 210b ... Cylindrical body 210c ... Elastic layer 210d ... Rotating shaft 220 ... Pressure roller (pressing member) 220b ... Cylindrical body 220c ... Elastic layer 220d ... Rotating shaft 230 ... Double-sided printing Transport path 240 ... Housing 250 ... Bearing 260 ... Pressure lever 270 ... Pressure spring 290 ... Support shaft 300 ... Support shaft 310 ... Peeling member 320 ... Peeling member 6 ... Nozzle 7 ... Cylinder 8 ... Sample 9 ... Load surface T ... toner

Claims (11)

A toner to which an external additive is applied in the vicinity of the surface of the toner base particles,
The toner base particles are formed by joining a plurality of fine particles,
Mainly toner mother particles having a constricted portion on the outer periphery of the bonding surface of the fine particles,
The toner according to claim 1, wherein the external additive is unevenly distributed in the vicinity of the constricted portion.   2. The toner according to claim 1, wherein the constricted portion is provided over substantially the entire circumference of the toner base particle with the normal line of the joint surface as an axis.   The toner according to claim 1, wherein the fine particles have an average particle size of 1.0 to 8.5 μm.   4. The toner according to claim 1, wherein an average length of the bonding surface of the fine particles in the projected shape of the toner base particles is 0.3 to 6.0 μm. The difference (L ₁ −L ₂ ) between the average particle diameter L ₁ [μm] of the fine particles and the average length L ₂ [μm] of the bonding surface of the fine particles in the projected shape of the toner mother particles is 0.7 to The toner according to claim 1, which is 5.0 μm.   The toner according to claim 1, wherein the external additive has an average particle diameter of 10 to 500 nm.   The toner according to claim 1, wherein the toner contains 1.0 to 5.0 parts by weight of the external additive with respect to 100 parts by weight of the toner base particles.   The toner according to claim 1, wherein an average particle diameter of the toner base particles is 2.0 to 10.0 μm. The relationship of 0.50 ≦ L ₁ / L ₀ ≦ 0.85 is satisfied, where L ₀ [μm] is the average particle size of the toner base particles and L ₁ [μm] is the average particle size of the fine particles. Item 9. The toner according to any one of Items 1 to 8.   The ratio of the toner base particles formed by bonding two fine particles to the whole toner base particles constituting the toner is 20 to 80% by number, and the toner formed by bonding three or more fine particles. The ratio of the mother toner particles is 5 to 45% by number, and the ratio of the toner mother particles formed by bonding two fine particles is more than the ratio of the toner mother particles formed by bonding three or more fine particles. The toner according to claim 1, which is larger. 11. The toner according to claim 1, wherein an average value (average circularity) of circularity R represented by the following formula (I) for the toner base particles is 0.92 to 0.98.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner base 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 base particles to be measured) Represents the perimeter of

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