JP2005115233A - Method for manufacturing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a spheric toner which can be fixed at a low temperature and by which the yield (recovery weight) can be increased in the process of mixing with external additive particle while the amount of isolated external additives or positively charged toner is little, and narrow distribution of charges is obtained. <P>SOLUTION: The method for manufacturing toner includes a process of mixing spheric resin particles containing at least a colorant with external additive particles in a spheric mixing tank. The spheric mixing tank has a horizontal tank bottom and such a configuration that stirring blades are attached to a driving shaft perpendicularly penetrating the center of the tank bottom of a horizontal disk form, and that the material to be processed is discharged upward from the periphery of the tank bottom along the inner wall of the mixing tank by the stirring blades and the discharged material is again supplied to the stirring blades. The spheric resin particles have 1.05 to 1.40 in shape factor (ML2/A), 1.05 to 1.30 in shape factor (PM2/A) and 100 to 130°C flow in softening point (Tf1/2). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing toner used for electrophotography, electrostatic recording, electrostatic printing, and the like.

  In the electrophotographic method, for example, after an electrophotographic toner is once attached to an image carrier such as a photoconductor on which an electrostatic latent image is formed, the image is transferred with or without an intermediate transfer medium in a transfer process. It is transferred to paper or the like, and is fixed by heat and pressure on the paper surface in the fixing step. As such an electrophotographic toner, a polymerization method toner and a pulverization method toner are known. As the polymerization method toner, for example, a release agent, a colorant, a charge control agent, a polymerization initiator and the like are included in a polymerizable monomer. The polymerizable monomer composition obtained by adding and uniformly dissolving or dispersing using a dispersing machine is charged into an aqueous phase containing a dispersion stabilizer, dispersed, polymerized, and toner base particles. As the pulverized toner, for example, a release agent, a colorant, a charge control agent, etc. are dispersed in a binder resin, and then pulverized to a toner size and classified by a fine pulverization means to form toner base particles. Each of the obtained toner base particles is mixed with external additive particles for the purpose of improving fluidity and stabilizing chargeability to obtain an electrophotographic toner. As electrophotographic toners, there are one-component magnetic toners and one-component non-magnetic toners depending on the development method, and there are two-component toners composed of toner particles and carrier particles.

  In the mixing process of the toner base particles and the external additive in the production of such a toner, a Henschel mixer is frequently used as a mixing processing tank. As shown in FIG. 3, the Henschel mixer has a cylindrical mixing treatment tank 1 and has a stirring blade that rotates at a high speed at the bottom of the mixing tank, and is generated by a lower blade 5 that rotates at a high speed at the bottom of the tank. The object to be processed is moved to the tank wall by force and the vertical tank wall of the cylinder is raised. Mixing is promoted by sliding up and down the formed inclined surface and repeating the up-and-down motion in which the centrifugal force is applied again by the blades rotating at high speed and the ascending motion is repeated. Further, the blade has a two-stage upper and lower structure, and the upper blade 10 is rotated in the middle of sliding down the inclined surface due to the deposition of the workpiece itself to stir the workpiece to promote dispersion. In such a mixing treatment tank, the movement direction of the object to be processed is suddenly changed at the rising portion of the cylindrical mixing treatment tank, so that heat is generated due to the change in the momentum. There arises a problem that the yield is lowered due to welding in the blade tip or inside the mixing treatment tank.

  Recently, in electrophotography, there has been a demand for low-temperature fixing of toner due to higher speed and energy saving, and internal dispersion in which release agent particles are dispersed in a binder resin for the purpose of low-temperature melting characteristics of toner particles. Type toners and toners in which the binder resin itself has melting characteristics suitable for low-temperature fixing have been developed. Such a toner that can be fixed at a low temperature is such that when a Henschel mixer is used in the mixing process with the external additive particles, the object to be processed is welded at the tip of the blade or inside the mixing tank, resulting in a decrease in yield. The problem becomes more pronounced.

  In addition, it is desirable that the external additive particles be uniformly dispersed and adhered to the surface of the toner base particles. However, in the Henschel mixer, the object to be processed is left as it is due to gravity on the inclined surface formed by the deposition of the object to be processed. It only slides down, does not roll easily, tends to result in contact of the same part of the particles, and there is a problem with the desired dispersed adhesion state of uniform adhesion. For this reason, the mixing time is lengthened for uniform adhesion, and stirring with the upper blade is made strong.

  In recent years, Henschel mixers have been used to externally add toner particles having a small particle diameter of 3 to 10 μm for the purpose of high-definition images and spherical toner shapes for the purpose of improving transfer efficiency. Is described that the stirring blade (lower blade) in the Henschel mixer has high linearity for the purpose of uniform dispersion adhesion of the external additive particles to the toner base particles (Patent Document 1). However, the above-described problems still remain in the toner that enables low-temperature fixing.

Also, there are known ones in which the mixing tank is spherical (Patent Documents 2 and 3). However, in these documents, toner base particles suitable for a spherical processing layer are added to the external processing of the toner base particles. It does not describe sphericity and does not describe application to a toner that enables low-temperature fixing. Although toner base particles having high sphericity are excellent in rolling properties, toner base particles having high sphericity have a relatively small surface area and less surface irregularities than irregular toner. Therefore, it is difficult to uniformly deposit a predetermined amount of external additive particles, and there is a problem that the stirring speed must be increased. In particular, with toner that can be fixed at low temperature, increasing the stirring speed in the mixing tank will cause welding at the blade tip and inside the mixing tank, resulting in a decrease in yield (recovered weight) and vice versa. There is a problem in that the amount of charged toner increases, and the charge amount distribution (Q / m) cannot be narrowed.
JP-A-9-96923 Japanese Patent Laid-Open No. 8-173783 JP 2002-268277 A

  The present invention relates to a method for producing a low-temperature fixable spherical toner, which can increase the yield (recovered weight) during mixing with external additive particles, and can reduce the amount of free external additive and the amount of positively charged toner. It is an object of the present invention to provide a method for producing toner having a narrow amount distribution.

  The toner manufacturing method of the present invention is a toner manufacturing method in which spherical resin particles containing at least a colorant and external additive particles are mixed using a spherical mixing processing tank. A stirring blade is attached to a horizontal tank bottom and a drive shaft that vertically penetrates the center of the horizontal disk-shaped tank bottom, and the object to be processed is directed upward along the inner wall of the processing tank by the stirring blade. And the workpiece to be discharged is re-supplied to the stirring blade, and the shape factor (ML2 / A) of the spherical resin particles is 1.05 to 1.40, The coefficient (PM2 / A) is 1.05 to 1.30, and the flow softening point (Tf1 / 2) is 100 to 130 ° C.

  The external additive particles are silica particles that are at least hydrophobized.

  In the toner manufacturing method of the present invention, a toner having a specific sphericity that can be fixed at a low temperature is externally added using a spherical mixing processing tank, so that the amount of welding in the mixing processing tank is small and the yield is low. (Recovered weight) can be a high production method, and the adhesion of external additive particles to toner base particles can be made uniform and strong, and the amount of free external additive and positively charged toner is small, and the charge amount distribution Since a narrow and uniform external addition process can be performed, an image can be formed with a low fog in a toner that is excellent in transfer efficiency and suitable for low-temperature fixing during image formation.

  The toner base particles used in the toner production method of the present invention are spherical resin particles containing at least a colorant, and the spherical resin particles have a shape factor (ML2 / A) of 1.05 to 1.40. Further, the shape factor (PM2 / A) is 1.05 to 1.30, and the flow softening point (Tf1 / 2) is 100 to 130 ° C.

  The shape factor (ML2 / A) and shape factor (PM2 / A) of the toner base particles are 500 toner images of 3 μm or more obtained by enlarging the toner base particles dispersed in water together with the dispersant 200 times with an optical microscope. Randomly sampled and obtained image information is introduced into the image analysis device (Luzex AP) manufactured by Nicole via the interface and analyzed, and the longest length of the real particle, the perimeter of the projected image of the real particle The projected area of each real particle is obtained and defined as a value obtained by calculation using the following equation.

ML2 / A = (π / 4) (longest length of real particle) ² / (projected area of real particle)
PM2 / A = (peripheral length of projected image of real particle) ² / (4π · projection area of real particle)
The shape factor (ML2 / A) indicates the degree of spherical shape of the toner base particles, and the shape factor (PM2 / A) indicates the degree of unevenness on the surface of the toner base particles. If the shape factor (ML2 / A) of the toner base particles exceeds 1.40 and the shape factor (PM2 / A) exceeds 1.30, the spherical shape approaches an indeterminate shape and the fluidity in the mixing treatment tank is poor. Even if the peripheral speed of the stirring blade is lowered, the yield is lowered, and the amount of positively charged toner is increased, and the charge amount distribution is expanded.

  Further, when the shape factor (ML2 / A) of the toner base particles is smaller than 1.05 and the shape factor (PM2 / A) is smaller than 1.05, the spherical shape approaches a true sphere and externally added to the toner base particles. It is difficult to uniformly adhere the agent particles, so the peripheral speed of the stirring blade must be increased, welding to the blade tip and the tank wall occurs, the yield decreases, and the amount of free external additive The amount of charged toner also increases and the charge amount distribution tends to widen.

  The spherical resin particles have a shape factor (ML2 / A) of 1.05-1.40, preferably 1.05-1.30, and a shape factor (PM2 / A) of 1.05-1. 30, preferably 1.05-1.20. Further, the value of the shape factor (ML2 / A) is preferably larger than the value of the shape factor (PM2 / A). By setting the toner shape to such a specific sphericity, it is possible to provide a toner manufacturing method with excellent toner yield, and a toner having a small amount of free external additive and positively charged toner and a narrow charge amount distribution. .

  The toner produced in the present invention is a negatively chargeable toner obtained by attaching external additive particles to toner base particles. The toner base particles contain a binder resin and a colorant, and are necessary. Accordingly, it contains internal additives such as a release agent, a dispersant, a charge control agent, and a magnetic agent. Examples of the binder resin include polystyrene resin, acrylate resin or methacrylate resin (hereinafter referred to as (meth) acrylate resin), styrene-acrylic resin, polyester resin, polyethylene resin, epoxy resin, silicone resin, polypropylene. Resins, fluororesins, polyamide resins, polyvinyl alcohol resins, polyurethane resins, polyvinyl butyral resins, and copolymers containing components of these resins are used.

  Such binder resins include those that are charged positively or weakly negatively as the resin itself, and examples thereof include polystyrene resins and styrene-acrylic resins.

  Examples of polystyrene resins include hydrogenated styrene resins, styrene-isobutylene copolymers, acrylonitrile-butadiene-styrene copolymers (ABS resins), acrylonitrile-styrene copolymers (AS resins), acrylonitrile-polyethylene chloride-styrene. Copolymer (ACS resin), styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene crosslinked polymer, styrene-butadiene-chlorinated paraffin copolymer, styrene-allyl alcohol copolymer, Examples thereof include styrene-butadiene rubber, styrene-maleic ester copolymer, styrene-isobutylene copolymer, and styrene-maleic anhydride copolymer.

  Examples of the styrene- (meth) acrylate resin copolymer include acrylate-styrene-acrylonitrile copolymer (ASA resin), styrene-diethylamino-ethyl methacrylate copolymer, styrene-methyl methacrylate copolymer, Styrene-n-butyl methacrylate copolymer, styrene-methyl methacrylate-n-butyl acrylate copolymer, styrene-methyl methacrylate-butyl allylate-N- (ethoxymethyl) acrylamide copolymer, styrene-glycidyl methacrylate Copolymer, styrene-butadiene-dimethylaminoethyl methacrylate copolymer, styrene-acrylic ester-maleic ester copolymer, styrene-methyl methacrylate-ethyl 2-acrylate Sil copolymer, styrene-n-butylarylate-ethyl glycol methacrylate copolymer, styrene-n-butyl methacrylate-acrylic acid copolymer, styrene-n-butyl methacrylate-maleic anhydride copolymer, styrene -Butyl acrylate-isobutyl maleic acid half ester-divinylbenzene copolymer, styrene-butadiene-acrylate copolymer, styrene-acrylate copolymer and the like. To these binder resins, a negative charge control agent is usually added to produce toner base particles having an appropriate negative charge amount.

  Examples of the resin that is negatively charged as the binder resin itself include a resin having a substituent such as a carboxyl group, a phenyl group, a thiophenyl group, or a sulfonic acid group in the side chain. These substituents are preferably in the form of metal salts. The metal salt is preferably a metal salt with zinc, magnesium, aluminum, sodium, calcium, chromium, iron, manganese, cobalt or the like. Alternatively, these substituents may be in the form of a salt with an organic base such as an ammonium ion, pyridinium ion, imidazolium ion or the like. As the negatively chargeable resin, a polyester resin is most preferably used.

  The polyester resin is obtained by polycondensation of a polyhydric alcohol and a polyvalent carboxylic acid or a derivative thereof, and has a carboxyl group in the side chain. As the polyhydric alcohol, dihydric alcohol, trihydric alcohol or tetrahydric or higher alcohol is used. Examples of the dihydric alcohol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, Examples include dipropylene glycol, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct. Examples of the trihydric alcohol include glycerol, trimethylolpropane, trimethylolethane, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methylpropanetriol, 2-methyl-1,2,4- Examples include butanetriol and 1,3,5-trihydroxymethylbenzene. Examples of the tetravalent or higher alcohol include sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, and the like. Among these, neopentyl glycol, totimethylol propane, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct are preferably used, and these polyhydric alcohols are used alone or in combination.

  Examples of the polyvalent carboxylic acid include divalent carboxylic acids, trivalent or higher carboxylic acids, and derivatives thereof. Examples of the divalent carboxylic acid include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, phthalic acid, terephthalic acid, and isophthalic acid. These lower alkyl esters or acid anhydrides are used as derivatives of divalent carboxylic acids. As the lower alkyl ester, an alkyl ester having 1 to 12 carbon atoms, preferably a methyl ester or an ethyl ester is preferably used. Of these, phthalic acid, terephthalic acid, isophthalic acid, lower alkyl esters thereof, or anhydrides thereof, which are divalent carboxylic acids having an aromatic ring, are preferably used.

  Examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1 , 2,4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexatricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl ) Methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid. Examples of these derivatives include lower alkyl esters or acid anhydrides of these carboxylic acids.

  There is no restriction | limiting in particular in the manufacturing method of a polyester resin, It manufactures by polycondensing a polyhydric carboxylic acid and a polyhydric alcohol by the method normally used by those skilled in the art. In the polycondensation, the molar ratio of the carboxyl group to the hydroxyl group (OH / COOH) is preferably between 0.8 and 1.4 as the reaction amount of the polyvalent carboxylic acid and the polyhydric alcohol. Moreover, it is preferable to adjust the acid value of the polyester resin obtained so that it may become 1-100 mgKOH / g. More preferably, it is 1-30. When the acid value is less than 1 mgKOH / g, the dispersibility of the internal additives such as the charge control agent, the release agent, and the colorant with respect to the binder resin decreases. When the acid value exceeds 100 mgKOH / g, the moisture resistance of the toner decreases.

  In particular, when a high level of offset resistance and transparency (fixed image smoothness) are desired, it is preferable to use a urethane-modified polyester resin as the polyester resin. The urethane-modified polyester resin is obtained by a reaction between a polyester resin and an isocyanate, and the isocyanate is 0.3 to 0.99 mole equivalent, preferably 0.5 to 0.95 mole equivalent per mole equivalent of hydroxyl group of the polyester resin. The reaction may be performed at a mixing ratio. If the molar ratio of isocyanate is less than 0.3, offset resistance may be lowered. If it is greater than 0.99, the viscosity rises remarkably and stirring may become difficult. Although there is no restriction | limiting in particular as isocyanate, Hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, etc. are used preferably.

  As the colorant, organic pigments, inorganic pigments, and dyes as shown below can be used. Among organic and inorganic pigments, carbon black, copper oxide, iron tetroxide, manganese dioxide, aniline black, activated carbon, etc. are used as the black pigment.

  Yellow pigments include chrome yellow, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, hansa yellow, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow. NCG, tartrazine lake, etc. are used.

  As the orange pigment, red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GKM and the like are used.

  Red pigments include Bengala, Cadmium Red, Red Plum, Mercury Sulfide, Cadmium, Permanent Red 4R, Risor Red, Pyrozolone Red, Watching Red, Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B Alizarin lake, Brilliant Carmine 3B, etc. are used.

  As the purple pigment, manganese purple, fast violet B, methyl violet lake and the like are used. As the blue pigment, bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated product, first sky blue, indanthrene blue BC, and the like are used.

  As the green pigment, chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G, or the like is used.

  As the white pigment, zinc white, titanium oxide, antimony white, zinc sulfide and the like are used.

  Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.

  As the dye, basic dyes, acid dyes, disperse dyes, direct dyes, and the like are used. Examples of such dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

  When the present invention is a translucent color toner, the following various pigments and dyes are used as the colorant.

  Examples of yellow pigments include CI10316 (Naphthol Yellow S), CI11710 (Hansa Yellow 10G), CI11660 (Hansa Yellow 5G), CI11670 (Hansa Yellow 3G), CI11680 (Hansa Yellow G), CI11730 (Hansa Yellow GR), CI11735 (Hansa Yellow A), CI11740 (Hansa Yellow NR), CI12710 (Hansa Yellow R), CI12720 (Pigment Yellow L), CI21090 (Benzidine Yellow), CI21095 (Benzidine Yellow G), CI21100 (Benzidine Yellow GR), CI20040 (Permanent Yellow NCG), CI21220 (Vulcan Fast Yellow 5), CI21135 (Vulcan Fast Yellow R), etc. are used.

  Red pigments include CI12055 (Starlin I), CI12075 (Permanent Orange), CI12175 (Risor Fast Orange 3GL), CI12305 (Permanent Orange GTR), CI11725 (Hansaero 3R), CI21165 (Vulcan Fast Orange GG) ), CI21110 (Benzidine Orange G), CI12120 (Permanent Red 4R), CI1270 (Paral Red), CI12085 (Fire Red), CI12315 (Brilliant Fast Scarlet), CI12310 (Permanent Red F2R), CI12335 ( Permanent Red F4R), CI12440 (Permanent Red FRL), CI12460 (Permanent Red FRLL), CI12420 (Permanent Red F4RH), CI12450 (Light Fast Red Toner B), CI12490 (Permanent Carmine FB), CI15850 ( Brilliantka Min 6B) and the like can be used.

  As the blue pigment, C.I.74100 (metal-free phthalocyanine blue), C.I.74160 (phthalocyanine blue), C.I.74180 (first sky blue), or the like is used.

  These colorants can be used alone or in combination of two or more, but it is desirable to use 1 to 20 parts by mass, preferably 2 to 10 parts by mass with respect to 100 parts by mass of the binder resin. When the amount is more than 20 parts by mass, the toner fixing property and transparency are deteriorated. On the other hand, when the amount is less than 1 part by mass, a desired image density may not be obtained.

  Release agents include paraffin wax, polyolefin wax, modified wax having aromatic group, hydrocarbon compound having alicyclic group, natural wax, long chain fatty acid having 12 or more carbon atoms or ester thereof, long chain fatty acid metal Salts (metal soaps), fatty acid amides, fatty acid bisamides and the like are used. Of the release agents, paraffin wax, polyolefin wax and metal soap are preferably used.

  Examples of the paraffin wax include paraffin wax (manufactured by Nippon Oil Co., Ltd. or Nippon Seiwa Co., Ltd.), micro wax (manufactured by Nippon Oil Co., Ltd.), and microcrystalline wax (manufactured by Nippon Seiwa Co., Ltd.). , Hard paraffin wax (manufactured by Nippon Seiwa Co., Ltd.), PE-130 (manufactured by Hoechst), Mitsui High Wax 110P (manufactured by Mitsui Petrochemical Co., Ltd.), Mitsui High Wax 220P (manufactured by Mitsui Petrochemical Co., Ltd.), Mitsui High Wax 660P (Mitsui Petrochemical Co., Ltd.), Mitsui High Wax 210P (Mitsui Petrochemical Co., Ltd.), Mitsui High Wax 320P (Mitsui Petrochemical Co., Ltd.), Mitsui High Wax 410P (Mitsui Petrochemical) ), Mitsui High Wax 420P (Mitsui Petrochemical Co., Ltd.), modified wax JC-1141 (Mitsui Petrochemical Co., Ltd.), modified wax JC-2130 (Mitsui Petrochemical Co., Ltd.), Modified wack JC-4020 (Mitsui Petrochemical Co., Ltd.), modified wax JC-1142 (Mitsui Petrochemical Co., Ltd.), modified wax JC-5020 (Mitsui Petrochemical Co., Ltd.), beeswax, carnauba wax, Montan A wax etc. can be mentioned.

  Examples of the polyolefin wax include low molecular weight polypropylene, low molecular weight polyethylene, oxidized polypropylene, oxidized polyethylene, and the like. Specific examples of polyolefin waxes include, for example, Hoechst Wax PE520, Hoechst Wax PE130, Hoechst Wax PE190 (manufactured by Hoechst), Mitsui High Wax 200, Mitsui High Wax 210, Mitsui High Wax 210M, Mitsui High Wax 220, Mitsui High Wax Non-oxidized polyethylene wax such as 220M (Mitsui Petrochemical Industries), Sun Wax 131-P, Sun Wax 151-P, Sun Wax 161-P (Sanyo Chemical Industries), Hoechst Wax PED121, Hoechst Wax PED153, Hoechst Wax PED521, Hoechst Wax PED522, Ceridust 3620, Ceridust VP130, Ceridust VP5905, Ceridust VP9615A, Ceridust TM9610F, Ceridust3715 (manufactured by Hoechst), Mitsui High Wax Chemicals 420M ) Oxidized polyethylene wax such as Sun Wax E-300, Sun Wax E-250P (Sanyo Kasei Kogyo Co., Ltd.), Hoechis t Non-oxidized polypropylene wax such as Wachs PP230 (Hoechst), Biscol 330-P, Biscol 550-P, Biscol 660P (Sanyo Chemical Industries), and Biscol TS-200 (Sanyo Chemical Industries, Ltd.) Oxidized polypropylene wax, such as

  As the fatty acid metal salt (metal soap), zinc stearate, calcium stearate, magnesium stearate, zinc oleate, zinc palmitate, magnesium palmitate and the like are preferably used.

  These release agents can be used alone or in combination. As the release agent, a compound having a low softening point (melting point) is preferable, and those having a softening point of 40 to 130 ° C, preferably 50 to 120 ° C are preferably used. The softening point is represented by an endothermic main peak value in a DSC endothermic curve measured by “DSC120” manufactured by Seiko Instruments Inc.

  As a dispersant, metal soap, polyethylene glycol or the like may be added.

  The charge control agent is used as necessary to control the chargeability of the toner base particles. When the degree of negative chargeability of the binder resin itself is low, or when the binder resin itself is positively charged, the entire toner base particles have a desired level of negative chargeability using a negative charge control agent. To have.

  Examples of the negative charge control agent include metal salts or metal complexes of salicylic acid derivatives, metal salts of benzylic acid derivatives, and phenylborate quaternary ammonium salts. As the metal salts of salicylic acid derivatives or benzylic acid derivatives, these zinc salts, nickel salts, copper salts, chromium salts and the like are preferably used. Examples of commercially available negative charge control agents include oil black (Color Index 26150), oil black BY (manufactured by Orient Chemical Co., Ltd.), Bontron S-22 (manufactured by Orient Chemical Co., Ltd.), and salicylic acid metal complex E. -81 (produced by Orient Chemical Co., Ltd.), thioindigo pigment, sulfonylamine derivative of copper phthalocyanine, Spiron Black TRH (produced by Hodogaya Chemical Co., Ltd.), Bontron S-34 (produced by Orient Chemical Co., Ltd.) ), Nigrosine SO (manufactured by Orient Chemical Industry Co., Ltd.), Ceres Schwartz (R) G (manufactured by Farben Fabricen Bayer), Chromogen Schwarz ETOO (CINO.14645), Azo Oil Black (R) (National Aniline). Among these, salicylic acid metal complex E-81 is preferably used. These negative charge control agents can be used alone or in combination. The negative charge control agent is preferably blended in the binder resin so that the charge amount of the toner base particles is −5 to −60 μC / g. Therefore, although the addition amount with respect to binder resin is determined by the kind of binder resin to be used, generally it mix | blends in 0.1-5 mass parts with respect to 100 mass parts of binder resin.

  The positive charge control agent is internally added to the negative charge resin as necessary to adjust the negative charge amount of the toner base particles. A commercially available positive charge control agent is used as the positive charge control agent. For example, Nigrosine Base EX (manufactured by Orient Chemical Industries, Ltd.), quaternary ammonium salt P-51 (manufactured by Orient Chemical Industries, Ltd.), Nigrosine Bontron N-01 (manufactured by Orient Chemical Industries, Ltd.), Sudan Chief Schwarz BB (Solvent Black 3: Color Index 26150), Fettschwarz HBN (CINO.26150), Brilliant Spirits Schwarz TN (manufactured by Farben Fabrikken Bayer), Zavon Schwartz X (manufactured by Farberge Hoechst). Of these, the quaternary ammonium salt P-51 is preferably used. In addition to the above, alkoxylated amines, alkylamides, molybdate chelate pigments and the like are also used as positive charge control agents. These positive charge control agents can be used alone or in combination.

Examples of magnetic agents include metal powders such as Fe, Co, Ni, Cr, Mn, and Zn, composite metal oxides such as Fe ₃ O ₄ , Fe ₂ O ₃ , Cr ₂ O ₃ , and various ferrites, manganese and acid. An alloy exhibiting ferromagnetism or the like may be added by heat treatment of the alloy or the like containing the alloy, and those previously treated with a coupling agent or the like may be used.

  As the toner base particles, any of toner base particles obtained by a pulverization method or a polymerization method may be used. As the pulverized toner, (1) a predetermined amount of additives such as a binder resin, a colorant, and a release agent are introduced into a mixer such as a Henschel mixer 20B (Mitsui Mining Co., Ltd.), and uniformly. Mix. (2) Next, the obtained mixture is charged into a twin-screw kneading extruder (PCM-30 manufactured by Ikekai Kasei Co., Ltd.) and uniformly melt-kneaded. Other melt kneading means include batch-types such as continuous kneaders such as “TEM-37” (Toshiba Machine Co., Ltd.), “KRC Kneader” (Kurimoto Iron Works Co., Ltd.), and heating / pressure kneaders. Examples thereof include a kneader. (3) The obtained melt-kneaded product is finely pulverized using a pulverizing means to obtain toner mother particles having a desired average particle diameter. For the pulverization, for example, a mechanical pulverizer turbo mill (Kawasaki Heavy Industries, Ltd.) is used in addition to the collision pulverization by jet air using a jet pulverizer 200AFG (Hosokawa Micron Corporation) or IDS-2 (Nippon Pneumatic Industry Co., Ltd.). ), Super Rotor (Nisshin Engineering Co., Ltd.) or the like. (4) After pulverization, the particle size of the obtained toner base particles is adjusted using wind power or rotor rotation. For example, when a wind classifier 100ATP (Hosokawa Micron Co., Ltd.), DSX-2 (Nippon Pneumatic Industry Co., Ltd.) or Elbow Jet (Nittetsu Mining Co., Ltd.) is used, a sharp particle size distribution is obtained. (5) In the pulverization process, the spheroidizing process of the pulverized toner uses a relatively round spherical pulverizing apparatus, for example, a turbo mill (manufactured by Kawasaki Heavy Industries) known as a mechanical pulverizer, or the particle size is adjusted. The toner is processed by a hot air spheronizer (manufactured by Nippon Pneumatic Industry), and its shape factor (ML2 / A) and shape factor (PM2 / A) are adjusted within the above-mentioned ranges.

  Next, the polymerization toner is obtained by suspension polymerization, emulsion polymerization, dispersion polymerization, or the like. In the suspension polymerization method, a monomer in which a polymerizable monomer, a color pigment, a release agent, and if necessary, a dye, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives are dissolved or dispersed. The composition is added to an aqueous phase containing a suspension stabilizer (water-soluble polymer, poorly water-soluble inorganic substance) with stirring, granulated and polymerized to form colored toner base particles having a desired particle size. To do. In the materials used for the production of the polymerization toner, the same materials as those of the pulverized toner described above can be used for the colorant, the release agent, and the charge control agent.

  In the emulsion polymerization method, polymerization is performed by dispersing a monomer and a mold release agent, and if necessary, a polymerization initiator, an emulsifier (surfactant), etc. in water, followed by a colorant and a charge control agent in the aggregation process. By adding a coagulant (electrolyte) and the like, colored toner base particles having a desired particle size can be formed.

  Further, after dissolving an internal additive such as a binder resin, a colorant, and a release agent in an organic solvent, the toner base particles are dispersed in an aqueous solvent together with a dispersant / emulsifier, granulated, separated and dried. May be produced.

  As the polymerizable monomer component, known vinyl monomers can be used. For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p -Ethyl styrene, vinyl toluene, 2,4-dimethyl styrene, pn-butyl styrene, p-phenyl styrene, p-chloro styrene, divinyl benzene, methyl acrylate, ethyl acrylate, propyl acrylate, acrylic acid n- Butyl, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, methyl methacrylate, ethyl methacrylate, methacryl Propyl acid, N-butyl tacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, acrylic acid, methacrylic acid, maleic acid, fumaric acid , Cinnamic acid, ethylene glycol, propylene glycol, maleic anhydride, phthalic anhydride, ethylene, propylene, butylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propyleneate, acrylonitrile, Examples include methacrylonitrile, vinyl methyl ether, vinyl ethyl ether, vinyl ketone, vinyl hexyl ketone, vinyl naphthalene and the like. Examples of fluorine-containing monomers include 2,2,2-trifluoroethyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, vinylidene fluoride, ethylene trifluoride, tetrafluoroethylene, and trifluoropropylene. Since fluorine atoms are effective for negative charge control, they can be used.

  Examples of the emulsifier (surfactant) include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate, dodecyl ammonium chloride, dodecyl ammonium bromide. , Dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, hexadecyl trimethyl ammonium bromide, dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, and the like.

  Examples of the polymerization initiator include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 4,4′-azobiscyanovaleric acid, t-butyl hydroperoxide, benzoyl peroxide, 2,2′-azobis- There are isobutyronitrile and the like.

  Examples of the flocculant (electrolyte) include sodium chloride, potassium chloride, lithium chloride, magnesium chloride, calcium chloride, sodium sulfate, potassium sulfate, lithium sulfate, magnesium sulfate, calcium sulfate, zinc sulfate, aluminum sulfate, and iron sulfate. Can be mentioned.

  As a method for adjusting the sphericity of the polymerization toner, in the emulsion polymerization method, it can be appropriately adjusted by controlling the temperature and time during the aggregation process of the secondary particles. In addition, in the suspension polymerization method, spherical toner base particles are obtained, but the sphericity can be appropriately adjusted by heat-deforming at or above the Tg temperature of the toner base particles.

  The content of the release agent is 1 to 10 parts by weight, preferably 2 to 7 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint of grindability in the ground toner, and in the polymerization toner, Although it is 5 to 30 parts by mass, preferably 5 to 20 parts by mass, in the pulverized toner, the binder resin itself may have a low melting property. For example, Japanese Patent Application No. 2003-293707 filed earlier by the present applicant. Examples thereof include binder resins containing the crystalline polyester resin described in Japanese Patent Application Nos. 2003-293708 and 2003-293709.

  The mass average molecular weight of the binder resin is not particularly limited, but is usually 2,000 to 30,000, preferably 4,000 to 25,000, and more preferably 6,000 to 20,000. If the molecular weight is less than 2,000, the flow softening point (Tf1 / 2) becomes too low, and the durability is lowered. In the case of a pulverized toner, the viscosity at the time of kneading is lowered, and the colorant is dispersed. There is a possibility that it cannot be performed sufficiently, and the saturation or transparency of the obtained toner may be lowered. When the molecular weight is larger than 30,000, the flow softening point (Tf1 / 2) becomes too high to be a toner that can be fixed at low temperature, and the viscosity is too high for the pulverized toner, and the colorant May not be sufficiently dispersed, and the saturation or transparency of the toner may be reduced. Moreover, there exists a possibility that a grindability may fall. A plurality of resins having a molecular weight within the above range may be mixed to form a binder resin. The molecular weight of the binder resin is measured by gel permeation chromatography (GPC).

  The toner base particles of the present invention have a flow softening point (Tf1 / 2) of the toner base particles of 100 to 130 ° C., preferably 100 to 120 ° C. in order to make the toner suitable for heat-pressure fixing at a low temperature during image formation. It is said. Further, the glass transition temperature (Tg) of the toner base particles is 50 to 100 ° C., preferably 60 to 90 ° C. Incidentally, the flow softening point (Tf1 / 2) in the toner obtained by adhering the external additive particles is 100 to 130 ° C., preferably 100 to 120 ° C., and the heat and pressure conditions (140 to 200 ° C.) in the fixing step. The toner can be fixed at a linear pressure of 0.04 to 0.1 kgf / mm), so-called “low-temperature fixable toner”.

  The flow softening point (Tf1 / 2) was measured by pressure-molding 1.0 g of a binder resin into a pellet and using “Flow Tester CFT-500D” manufactured by Shimadzu Corporation under the following conditions. To do. Temperature rising rate 5 ° C./min; cylinder pressure 2.0 MPa; die hole diameter 1.0 mm; die hole length 1.0 mm; Tm calculation method 1/2 method. Further, the glass transition temperature (Tg) of the binder resin is measured under the following conditions using 10 mg of the binder resin packed in an aluminum cell and using “DSC120” manufactured by Seiko Instruments Inc. Measurement temperature 0 to 200 ° C .; temperature increase rate 10 ° C./min: Read from DSC curve at the second temperature increase.

  The volume average particle diameter of the toner base particles is 9 μm or less, preferably 3.0 μm to 8 μm for both the pulverized toner and the polymerized toner. For toner particles larger than 9 μm, even if a latent image is formed at a high resolution of 1200 dpi or higher, the reproducibility of the resolution is lower than that of a small particle diameter toner. In addition, the use amount of the external additive increases in order to improve the fluidity, and as a result, the fixing performance tends to decrease, which is not preferable. The average particle diameter of the toner base particles and toner particles described above and the external additive particles described later in the present invention is a value measured by a particle image analyzer (FPIA2100 manufactured by Sysmex).

In addition, the average charge amount of the toner particles to which the external additive particles are attached is preferably −5 to −30 μC / g. If the charge amount is smaller than this range, toner leakage from the developing device becomes severe. If the charge amount is larger than this range, it is necessary to apply an excessive developing bias in order to obtain a sufficient image density. Such problems arise. The charge amount is measured as follows. In an environment where the temperature is 25 ° C. and 45% RH, toner is put into a developing device of LP-1500 (manufactured by Seiko Epson Corporation), and the developing device is idled, and then the surface of the developing roller is 0.3 kg / cm ² . Nitrogen gas under pressure is blown, and the charge amount (Q) and mass m of each toner are measured using an E-SPART analyzer manufactured by Hosokawa Micron Co., Ltd., and the charge amount (Q / m) of the toner is measured. To do.

  Next, the process of mixing toner base particles and external additive particles, which is a feature of the present invention, will be described. In the mixing process of the toner base particles and the external additive particles, the spherical mixing processing tank shown in FIGS. 1 and 2 is used. FIG. 1 is a central sectional view, and FIG. 2 is a plan view of an example of a mixing blade. In the figure, 1 is a processing tank, 2 is a horizontal disk-shaped tank bottom, 3 is a drive shaft, 4 is a donut-shaped disk, 5 is a stirring blade, 6 is an air seal hole, 7 is a cylindrical member that releases seal air, 8 is a flange and 9 is a jacket.

  Hereinafter, the spherical mixing treatment tank will be described in detail. As shown in FIG. 1, the spherical mixing treatment tank 1 is stirred by a horizontal disk-shaped tank bottom 2 and a drive shaft 3 penetrating vertically through the center of the tank bottom 2. A blade (turbine blade) 5 is attached. A donut-shaped disk 4 is attached to the agitating blade 5 for reinforcement. The object to be processed is discharged upward along the inner wall of the processing tank 1 by the centrifugal force generated by the stirring blade 5. A cylindrical member 7 is disposed inside the container 1, and the object to be processed released by the stirring blade 5 is received by the outer wall surface of the cylindrical member 7 and then dropped. The object to be treated is re-supplied to the stirring blade 5 from between the center hole of the donut disk 4 and the drive shaft 3, and dispersion mixing proceeds by repeating the above.

  Further, the processing tank 1 has a spherical shape having a horizontal tank bottom 2 and is provided with a flange 8 at the center so as to be divided into two vertically, and the entire spherical part is provided with a jacket 9 and has a double structure. Then, the heat medium can be flowed to heat or cool the workpiece. A cylindrical member 7 that also serves as an input hole for the object to be processed is provided in the upper part of the processing tank 1, and a discharge port (not shown) for the object to be processed that has been externally added is provided in the lower part as appropriate. .

  As described above, the agitating blade 5 is attached to the drive shaft 3 in the vicinity of the bottom of the tank so as to be rotatable by external power. The tip of the agitation blade 5 is connected to the outer periphery of the donut-shaped disk 4 and the tank wall as shown in FIGS. It arrange | positions so that it may be located between. Further, the lower edge of the stirring blade 5 is formed in an arc shape along the spherical inner wall of the processing tank 1 as shown in FIG. 1, and the object to be processed is curved on the inner surface of the processing tank as indicated by an arrow by rotating. It is set as the shape which can discharge | release toward a processing tank top along. The seal air hole 6 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 7.

  From the viewpoint of uniform processability of the object to be processed and the ability to discharge the supplied air, the length of the cylindrical member 7 inside the container is 1/20 or more of the height from the donut disk 4 inside the container, The length is preferably 1/3 or more, but the upper limit is preferably a length that does not contact the powder surface when the workpiece is allowed to stand. In addition, the cylindrical member 7 may have a structure other than the cylindrical shape so that the seal air can be removed. For example, the cylindrical member 7 may have a structure having a slit.

  Further, the ratio of the diameter of the horizontal tank bottom 2 to the diameter of the treatment tank 1 is 0.25 to 0.80, and the ratio of the outer diameter of the donut disk 4 to the diameter of the horizontal tank bottom 2 is. Is 0.50 to 1.20, and the ratio of the diameter of the stirring blade 5 to the diameter of the treatment tank 1 is preferably 0.50 to 0.90. The ratio of the inner diameter to the outer diameter of the donut disk 4 is 0.5 to 0.95, preferably 0.7 to 0.8.

  Moreover, the preparation amount of the processing object to a spherical mixing processing tank is 0.1-0.9 by the ratio with respect to the volume of a processing tank, Preferably it is good to set it as 0.3-0.5. The peripheral speed of the tip of the stirring blade (π × outer diameter of blade × rotational speed / hour) is 20 m / s to 100 m / s, preferably 30 m / s to 70 m / s, and the mixing processing time is 0. 5 to 10 minutes, preferably 1 to 5 minutes. In order to break the temperature rise, it may be mixed in several times. It is desirable that the time for one mixing process at this time be within the above-mentioned range. When mixing the toner base particles and external additive particles, the peripheral speed is slow, or if the mixing process time is short, the mixing process becomes insufficient, and if the peripheral speed is too fast or the mixing process time is long, welding occurs. However, the yield is not preferable.

  Since the spherical mixing treatment tank can eliminate the sudden rise of the object to be processed as compared with the Henschel mixer as shown in FIG. 3, the toner mother particles and the external additive particles as the object to be processed are curved. It is possible to flow along the shape of the tank wall at a high speed, and the wall surface distance through which the material to be processed flows is long, so that the toner base particles are easy to roll, and uniform external addition processing can be performed in a short time. Furthermore, after moving the processing object to the ceiling of the mixing processing tank, it is supplied to the stirring blades at the bottom of the tank and reprocessed, so that the vertical movement of the processing object that was dependent on gravity is a cylindrical mixing processing tank Compared to the above, there is an advantage that it is more dynamic and that it is not necessary to provide an upper blade. When the external additive particles are strongly aggregated, a turbulent flow can be generated by providing a convex portion in the tank.

  The external additive particles in the present invention will be described. In the present invention, the toner base particles are mixed with at least silica fine particles that have been hydrophobized.

  First, as the negatively chargeable silica fine particles, those having an average particle diameter of 4 to 120 nm, preferably 5 to 70 nm, and more preferably 6 to 60 nm are used. The smaller the average particle diameter of the negatively chargeable silica fine particles, the higher the fluidity of the obtained toner. However, if the average particle diameter is smaller than 4 nm, the toner particles may be buried in the toner base particles. Moreover, when it exceeds 120 nm, there exists a possibility that fluidity | liquidity may worsen extremely. In the present specification, the average particle diameter of fine particles such as negatively chargeable silica, positively chargeable silica, toner base particles, and toner particles means a volume average particle diameter unless otherwise specified.

  As the negatively chargeable silica fine particles, negatively chargeable silica fine particles having a uniform particle diameter may be used alone, but it is preferable to use two or more negatively chargeable silica fine particles having different average particle diameters in combination. Generally, negatively-charged silica fine particles (small particle size silica) having a small average particle size are used, and this is used in combination with negatively-charged silica fine particles (large particle size silica) having a large average particle size. As a result, the absolute value of the charge amount can be increased as compared with the case of using only a small particle size silica, and the large particle size silica becomes resistance, and the small particle size silica is embedded in the toner base particles. Therefore, long-term charging stability is improved. Furthermore, it is possible to improve the fluidity of the toner, exhibit a blocking effect against heat, and improve the storage stability of the toner. Preferably, negatively charged silica fine particles having an average particle size of 5 to 20 nm, preferably 6 to 15 nm as small particle size silica, and negative particles having an average particle size of 20 to 70 nm, preferably 20 to 60 nm, as large particle size silica. It is preferable to use in combination with the chargeable silica fine particles. The difference in average particle size between the large particle size silica and the small particle size silica is preferably 10 nm or more, and more preferably 20 nm or more.

  The addition ratio of large particle size silica to small particle size silica is 1: 3 to 3: 1, preferably 1: 2 to 2: 1, more preferably 1: 1.5 to 1.5: by weight. A value of 1 is preferable for imparting fluidity to the toner and obtaining long-term charging stability. When large particle size silica and small particle size silica are used, they may be mixed and added to the toner base particles at the same time, either one may be added first, and then the other may be added.

  The addition amount of the negatively chargeable silica fine particles can vary depending on the particle size distribution or fluidity of the toner base particles, or the particle size distribution of the external additive, the desired charge amount, and the like. For example, in the case of silica having the small particle diameter, 0.5 to 2.0 parts by mass, preferably 0.7 to 1.5 parts by mass are added to 100 parts by mass of the toner base particles. In the case of a large particle size silica, 0.2 to 2.0 parts by mass, preferably 0.3 to 1.5 parts by mass is added. When the large particle size silica and the small particle size silica are used in combination, the total amount is 0.5 to 3.0 parts by mass, preferably 0.7 with respect to 100 parts by mass of the toner base particles, taking the above mixing ratio into consideration. Add ~ 2.5 parts by weight.

  The negatively chargeable silica fine particles are preferably hydrophobized. By making the surface of the negatively chargeable silica fine particles hydrophobic, the fluidity and chargeability of the toner are further improved. Hydrophobization of silica fine particles can be achieved by using silane compounds such as aminosilane, hexamethyldisilazane and dimethyldichlorosilane; or dimethyl silicone, methylphenyl silicone, fluorine-modified silicone oil, alkyl-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, etc. This silicone oil is used, for example, by a method commonly used by those skilled in the art, such as a wet method or a dry method. Examples of the hydrophobic negatively chargeable silica fine particles include commercially available RX200 and RX50 manufactured by Nippon Aerosil Co., Ltd., TG811F, TG810G and TG308F manufactured by Cabot Corporation.

  The positively chargeable silica fine particles have a volume average particle diameter of 10 to 50 nm, preferably 15 to 40 nm in consideration of fluidity. The positively chargeable silica fine particles are added in an amount of 0.1 to 1.0 parts by weight, preferably 0.2 to 0.8 parts by weight, based on 100 parts by weight of the toner base particles. When the negatively chargeable resin is used as the binder resin and the negatively chargeable silica fine particles are not used as the charge control agent, the positively chargeable silica fine particles are 0.1 to 2.0 mass with respect to 100 parts by mass of the toner base particles. Parts, preferably 0.3 to 1.5 parts by weight.

  The positively charged silica fine particles are preferably subjected to a hydrophobic treatment. By making the surface of the positively chargeable silica fine particles hydrophobic, the change in the chargeability with respect to the change in the external environment of the toner is reduced (that is, the stable chargeability is maintained) and the fluidity of the toner is improved. Therefore, it is preferable. The hydrophobization of the positively chargeable silica fine particles is performed by the same method as the above-described hydrophobization of the negatively chargeable silica fine particles. Examples of the hydrophobic positively chargeable silica fine particles include commercially available NA50H manufactured by Nippon Aerosil Co., Ltd. and TG820F manufactured by Cabot Co., Ltd.

  Further, as the external additive particles in the present invention, fine particles of titanium oxide having a relatively low electrical resistivity may be added in addition to the silica fine particles subjected to the hydrophobic treatment. Titanium oxide can take crystal forms such as rutile, anatase, and rutile-anatase. Any crystalline titanium oxide may be used, but the rutile-anatase type titanium oxide is easy to adjust the charge, and even if the number of printed sheets increases, the titanium oxide particles are not easily embedded in the toner base particles. It is preferably used in terms of Although there is no restriction | limiting in particular in the magnitude | size of a titanium oxide fine particle, It is preferable that a particle size or the magnitude | size of a major axis is a magnitude | size of 10-100 nm. In the case of rutile-anatase type titanium oxide, titanium oxide fine particles having a major axis of about 10 to 100 nm are preferable.

  The titanium oxide fine particles are added in an amount of 0.2 to 2.0 parts by weight, preferably 0.3 to 1.5 parts by weight, based on 100 parts by weight of the toner base particles. When titanium oxide fine particles and positively chargeable silica fine particles are used, the charge is added in a mass ratio of 1: 3 to 3: 1 without causing an extreme decrease in the electric resistance of the toner. It is preferable at the point which can adjust.

  The surface of the fine particles of titanium oxide is hydrophobic in order to reduce the change in chargeability with respect to changes in the external environment of the toner (that is, maintain stable chargeability) and improve the fluidity of the toner. Is preferred. Hydrophobization of the titanium oxide fine particles is carried out by the same method as that of the negatively chargeable silica fine particles. Examples of the hydrophobic titanium oxide fine particles include STT-30S manufactured by Titanium Industry Co., Ltd.

Inorganic fine particles other than titanium oxide fine particles can also be externally added for the purpose of controlling the chargeability and improving the fluidity. For example, inorganic fine particles include aluminum oxide, strontium oxide, tin oxide, zirconia, magnesium oxide, indium oxide and other metal oxide fine particles, silicon nitride and other nitride fine particles, silicon carbide and other carbide fine particles, calcium sulfate , Fine particles of metal salts such as barium sulfate and calcium carbonate, and inorganic fine particles such as a composite thereof. Metal oxide fine particles having an electrical resistivity of 10 ⁹ Ωcm or less and a relatively small electrical resistivity are preferably used. Although there is no restriction | limiting in particular in the magnitude | size of the inorganic fine particle to add, It is preferable that a particle size is a magnitude | size of 10-30 nm. These inorganic fine particles are preferably subjected to a hydrophobic treatment on the surface for the purpose of stabilizing charging characteristics. For the hydrophobization treatment, the same method as any of the above-described hydrophobic methods for the negatively chargeable silica fine particles and the positively chargeable silica fine particles is employed.

  In addition, examples of the external additive particles include long-chain fatty acids or salts thereof. As the long chain fatty acid, a saturated or unsaturated fatty acid having preferably 10 to 30 carbon atoms, more preferably 12 to 28 carbon atoms, and still more preferably 12 to 18 carbon atoms is used. The long-chain fatty acid may have a branch, but a linear saturated fatty acid such as stearic acid is preferably used. The long chain fatty acid is preferably used in the form of a salt, and more preferably in the form of a metal salt (so-called metal soap). Although there is no restriction | limiting in particular as a metal salt of a long chain fatty acid, For example, calcium salt, zinc salt, magnesium salt, aluminum salt, lithium salt etc. are mentioned. Examples of the metal soap include magnesium stearate, calcium stearate, zinc stearate and the like, and these fine particles are preferably used. The particles comprising a long-chain saturated fatty acid or a salt thereof may be used alone or in combination of two or more.

  The long-chain fatty acid or a salt thereof, particularly a long-chain fatty acid metal salt (metal soap), preferably has a volume average particle diameter or major axis diameter of 0.5 to 10 μm, and more preferably 1 to 5 μm. If the average particle diameter or the major axis diameter is out of this range, the effect as a binder, lubricant, flow aid, or toner aggregation preventing effect tends to be insufficient.

  Long chain fatty acids or salts thereof, particularly metal soaps, preferably have a melting point of about 100 to 160 ° C. from the viewpoint of heat resistance and lubricity. When the melting point is lower than 100 ° C., the heat resistance of the toner is lowered, and the toner may aggregate when stored in a high temperature environment. If it is higher than 160 ° C., the lubricating action may be reduced.

  The particles comprising a long-chain saturated fatty acid or a salt thereof are added in an amount of 0.1 to 1.0 parts by weight, preferably 0.1 to 0.5 parts by weight, based on 100 parts by weight of toner base particles. When the addition amount is less than 0.1 parts by mass, the effects as the binder, the aggregation preventing effect, the flow aid, the lubricant and the like may not be sufficiently exhibited. On the other hand, when the addition amount is more than 1.0 part by mass, the fluidity is inferior, the charge rising property is remarkably deteriorated, and noise such as fog may be generated.

  The toner produced in the present invention can be applied to both an image forming apparatus using a one-component toner described in detail in JP-A-2002-202622 and an image forming apparatus using a two-component toner. Further, the present invention can be applied to both a contact developing type image forming apparatus and a non-contact type image forming apparatus.

  A monomer mixture consisting of 80 parts by mass of styrene monomer, 20 parts by mass of butyl acrylate, and 5 parts by mass of acrylic acid, 105 parts by mass of water, 1 part by mass of nonionic emulsifier (Emulgen 950 manufactured by Daiichi Kogyo Seiyaku), anionic emulsifier (first It was added to an aqueous solution mixture of 1.5 parts by mass of Neogen R) manufactured by Kogyo Seiyaku Co., Ltd. and 0.55 parts by mass of potassium persulfate, and polymerization was performed at 70 ° C. for 8 hours while stirring in a nitrogen stream. After the polymerization reaction, the mixture was cooled to obtain a milky white resin emulsion having a particle size of 0.25 μm.

  Next, 200 parts by mass of this resin emulsion, 20 parts by mass of polyethylene wax emulsion (manufactured by Sanyo Chemical Industries, Ltd.) and 10 parts by mass of phthalocyanine blue were included as surfactants and 0.2 part by mass of sodium dodecylbenzenesulfonate. Disperse in 2 liters of water, add diethylamine to adjust pH to 5.5, add 0.3 parts by weight of aluminum sulfate as an electrolyte while stirring, then stir at high speed with a stirrer (TK homomixer) Dispersion was performed.

  Further, 40 parts by mass of a styrene monomer, 10 parts by mass of butyl acrylate, and 5 parts by mass of zinc salicylate were added together with 40 parts by mass of water. And polymerized for 5 hours to grow particles. In order to increase the bond strength of the associated particles after the polymerization was stopped, the temperature was raised to 95 ° C. while maintaining the pH at 5 or higher and held for 5 hours. Thereafter, the obtained particles were washed with water and vacuum dried at 45 ° C. for 10 hours to obtain cyan toner base particles.

  The average particle diameter of the cyan toner base particles was 7.1 μm, the flow softening point (Tf1 / 2) was 112.5 ° C., ML2 / A was 1.10, and PM2 / A was 1.06.

  1 g of toner base particles and 30 g of silica fine particles {1: 1 (weight ratio) mixture of RX200 (average particle diameter 12 nm) and RX50 (average particle diameter 40 nm)} manufactured by Nippon Aerosil Co., Ltd.} It loaded in the tank (Mitsui Mine Co., Ltd. make, Q type 20L).

  The spherical mixing tank has an internal volume of 20 liters, the length of the cylindrical member 7 inside the container is 1/11 of the height from the donut disk 4 inside the container, and the diameter of the tank bottom 2 and the processing tank 1 is 0.57, the ratio of the outer diameter of the donut disk 4 to the diameter of the horizontal tank bottom 2 is 1.10, the diameter of the stirring blade (turbine blade) 5 and the treatment tank 1 The ratio with the diameter is 0.75, and the ratio between the inner diameter and the outer diameter of the donut disk 4 is 0.73.

This spherical mixing tank is mixed with a seal air amount of 1.0 Nm ³ / h, a turbine blade peripheral speed of 60 m / s and a mixing time of 2 minutes, and negatively charged silica fine particles are externally added to the toner base particles. Processed. The ratio (yield) of the recovered weight to the input weight of the workpiece was 97.2%.

With respect to the obtained toner, the number free rate of silica fine particles was determined by using a particle analyzer (“PT1000” manufactured by Yokogawa Electric Corporation), and it was 1.5% by number. The total number of measurements was 5000. Here, the number release rate is calculated from the number of detected elements (Si) and is defined by the following equation.
Number release rate (%)
= Number of detected free external additives / total number of detected (external additives + toner base particles) × 100
Next, the obtained toner was loaded into a toner cartridge of a color printer (“LP1500” manufactured by Seiko Epson Corporation), and solid printing was performed. After printing, the toner cartridge was taken out, and the toner charge amount distribution on the developing roller was measured. For the measurement, a charge amount distribution measuring device (“E-SPART III” manufactured by Hosokawa Micron Corporation) was used, and the number of measurement was 3000. The positively charged toner amount was 4.2% by number, and the standard deviation of the charged amount (Q / m, μC / g) was 24.4.

  In the production of the toner base particles of Example 1, the wax emulsion was 15 parts by mass, the temperature and time were adjusted in the secondary particle aggregation process, the average particle size was 7.5 μm, and the flow softening point (Tf1 / 2) was 120. The resulting toner base particles were ML5 / A of 1.25 and PM2 / A of 1.08.

  The resulting toner base particles were externally treated with silica fine particles in the same manner except that the spherical mixing tank used in Example 1 was used and the peripheral speed was 50 m / s. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

  In the production of the toner base particles of Example 1, 10 parts by weight of the wax emulsion was used, and the temperature and time were adjusted during the aggregation process of the secondary particles to obtain an average particle size of 7.5 μm and a flow softening point (Tf1 / 2) of 128. The toner base particles were obtained at .2 ° C., ML2 / A of 1.30, and PM2 / A of 1.25.

  The resulting toner base particles were externally treated with silica fine particles in the same manner except that the spherical mixing tank used in Example 1 was used and the peripheral speed was 40 m / s. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

  50:50 (weight ratio) mixture of polycondensed polyester of aromatic dicarboxylic acid and alkylene etherified bisphenol A and a partially cross-linked product of the polycondensed polyester with a polyvalent metal compound (manufactured by Sanyo Chemical Industries, Ltd.) 100 mass 5 parts by mass of cyan pigment phthalocyanine blue, 5 parts by mass of polypropylene having a melting point of 152 ° C. and a weight average molecular weight Mw of 4000 as a release agent, and salicylic acid metal complex E-81 (Orient Chemical Industries ( 4 parts by mass) were mixed uniformly using a Henschel mixer, kneaded with a twin-screw extruder having an internal temperature of 150 ° C., and then cooled. Next, the cooled product is coarsely pulverized to 2 mm square or less, then finely pulverized by a jet mill, classified by a classifier by rotating a rotor, and then a hot air spheronizing device surfing system (SFS-3 type, manufactured by Nippon Pneumatic Industry) After use, the heat treatment temperature was set to 200 ° C., and the spheroidization treatment was partially performed, followed by classification in the same manner to obtain cyan toner base particles.

  The obtained cyan toner base particles had an average particle size of 8.1 μm, a flow softening point (Tf1 / 2) of 108.8 ° C., ML2 / A of 1.26, and PM2 / A of 1.10.

  3.0 kg of the obtained cyan toner base particles, 30 g of silica fine particles {1.5: 1.0 (weight ratio) mixture of RX200 (average particle size 12 nm) and RX50 (average particle size 40 nm) manufactured by Nippon Aerosil Co., Ltd.}} Was added to the spherical mixing tank (Q type 20L, manufactured by Mitsui Mining Co., Ltd.) used in Example 1, and externally added in the same manner except that the peripheral speed was 45 m / s. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

(Comparative Example 1)
In the production of the toner base particles of Example 2, the temperature and time were adjusted in the aggregation process of the secondary particles to obtain an average particle size of 7.5 μm, a flow softening point (Tf1 / 2) of 120.5 ° C., and ML2 / Toner mother particles having A of 1.26 and PM2 / A of 1.09 were obtained.

  The resulting toner base particles (3.0 kg) and silica fine particles {1: 1 (weight ratio) mixture of RX200 (average particle size 12 nm) and RX50 (average particle size 40 nm)} manufactured by Nippon Aerosil Co., Ltd.} are shown in FIG. The resulting Henschel mixer (Mitsui Mining Co., Ltd., Henschel 20L) was loaded, and silica fine particles were externally added to the toner base particles. The Henschel type mixer has an internal volume of 20 liters and a stirring blade shape YiA0. The peripheral speed of the stirring blade is 50 m / s and the mixing time is 2 minutes. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

(Comparative Example 2)
In the production of the toner base particles of Example 1, 25 parts by mass of the wax emulsion was used, and the temperature and time were adjusted in the secondary particle agglomeration process to obtain an average particle size of 6.9 μm and a flow softening point (Tf1 / 2) of 96. Further, toner mother particles having an ML2 / A of 1.04 and a PM2 / A of 1.04 were obtained.

  Silica fine particles were externally added to the obtained toner base particles in the same manner as in Comparative Example 1. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

(Comparative Example 3)
The toner base particles obtained in Comparative Example 2 were externally treated with silica fine particles in the same manner as in Comparative Example 1 except that the spherical mixing tank used in Example 1 was used and the peripheral speed was set to 70 m / s. .

  The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

(Comparative Example 4)
Toner base particles were produced in the same manner as in Example 4 except that in the production of the toner base particles of Example 4 by the pulverization method, the release agent was 3 parts by mass and the hot air spheronization treatment was omitted. Toner mother particles having an average particle size of toner base particles of 7.5 μm, a flow softening point (Tf1 / 2) of 132.5 ° C., ML2 / A of 1.48 and PM2 / A of 1.35 were obtained.

  3.0 kg of the toner base particles obtained and 40 g of silica fine particles {1.5: 1.0 (weight ratio) mixture of RX200 (average particle size 12 nm) and RX50 (average particle size 40 nm) manufactured by Nippon Aerosil Co., Ltd.}} Using the Henschel mixer used in Comparative Example 1, the mixing treatment was performed in the same manner. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

(Comparative Example 5)
The toner fine particles obtained in Comparative Example 4 were externally treated with silica fine particles in the same manner except that the spherical mixing tank used in Example 4 was used and the peripheral speed was 40 m / s. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

(Comparative Example 6)
The toner mother particles and the external additive particles in Example 4 were mixed using the Henschel mixer used in Comparative Example 1. The obtained toner was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

  From the table, Examples 1 to 4 can be a production method having a high yield in comparison with Comparative Examples 1 to 6, and the amount of free external additive and the amount of opposite polarity toner is small, and the toner has a narrow charge amount distribution. You can see that

FIG. 1 is a central sectional view of a spherical mixing treatment tank. FIG. 2 is a plan view of an example of the mixing blade. FIG. 3 is a central sectional view of the Henschel type mixing treatment tank.

Explanation of symbols

1 is a treatment tank, 2 is a horizontal disk-shaped tank bottom, 3 is a drive shaft, 4 is a donut-shaped disk, 5 is a stirring blade, 6 is an air seal hole, 7 is a cylindrical member that releases seal air, and 8 is a flange. , 9 is a jacket

Claims (2)

In a toner manufacturing method in which spherical resin particles containing at least a colorant and external additive particles are mixed using a spherical mixing processing tank, the spherical mixing processing tank includes a horizontal tank bottom, A stirring blade is attached to a drive shaft that vertically penetrates the center of the horizontal disk-shaped tank bottom, and the workpiece is discharged upward from the outer periphery of the tank bottom along the inner wall of the processing tank by the stirring blade. The processed product is re-supplied to the stirring blade, and the spherical resin particles have a shape factor (ML2 / A) of 1.05 to 1.40 and a shape factor (PM2 / A) of 1. A method for producing a toner, characterized in that the toner has a flow softening point (Tf1 / 2) of 100 to 130 ° C. from 05 to 1.30. 2. The method for producing a toner according to claim 1, wherein the external additive particles are at least hydrophobized silica particles.

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