JP2006072121A - Method for manufacturing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method by which toner containing a small amount of positively charged toner particles, having a sharp charge amount distribution and excellent in durability in printing on a large number of sheets can be manufactured in a high yield and in a short time. <P>SOLUTION: In the method for manufacturing the toner, external additive particles are externally added in multiple stages to spherical resin particles containing at least a colorant by using a spherical mixing tank with a water-cooling jacket, wherein at the time when the temperature of materials to be treated near a tank wall cooled by the water-cooling jacket after the first external addition is higher than the temperature of material to be treated near a tank wall before the first external addition, external additive particles in the second stage or later are put in and external addition treatment in the second stage or later is started. <P>COPYRIGHT: (C)2006,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, a pulverization method toner and a dissolution suspension toner are known. As the polymerization method toner, for example, a polymerization agent obtained by adding a release agent, a colorant, a charge control agent, a polymerization initiator, etc. in a polymerizable monomer and uniformly dissolving or dispersing it using a disperser. The monomer composition is charged into an aqueous phase containing a dispersion stabilizer, dispersed and polymerized to form toner mother particles. As a pulverized toner, for example, a release agent in a binder resin, After dispersing a colorant, a charge control agent, etc., the toner is pulverized and classified to a toner size by a fine pulverizing means to form toner mother particles. Further, as the dissolved suspended toner, for example, a resin, a colorant, and other additives can be used. A solution dissolved / dispersed in an organic solvent is charged into an aqueous phase and dispersed, and then the organic solvent is removed from the obtained emulsion particles and dried to form toner mother particles. Each of the obtained toner base particles is mixed with external additive particles for the purpose of improving fluidity and stabilizing the 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 toner, a mixing treatment tank is used. The input weight of the external additive particles is about several percent with respect to the input weight of the toner base particles. In order to avoid adhesion in the mixing tank, the external additive particles are introduced after the toner base particles in the order of introduction into the mixing tank. As the mixing treatment tank, a Henschel mixer is frequently used. The Henschel mixer has a cylindrical mixing treatment tank 1 as shown in FIG. 4, and has a stirring blade that rotates at a high speed at the bottom of the mixing tank. Yes, the object to be processed is moved to the tank wall by the centrifugal force generated by the lower blade 11 rotating at high speed at the bottom of the tank, and the vertical tank wall of the cylinder is raised. Mixing is promoted by repeating the up-and-down motion of sliding down the inclined surface formed by the deposition of the workpiece itself by gravity and rising again due to centrifugal force given by the blade rotating at high speed. The In addition, the blades have a two-stage structure, and the upper blade 10 is rotated and the object to be processed is agitated to promote dispersion while sliding down the inclined surface due to the deposition of the object itself.

  In such a mixing treatment tank, since the moving direction of the object to be processed is suddenly changed at the rising portion of the cylindrical mixing treatment tank, heat is generated due to a change in the momentum thereof. Is welded inside the blade tip or inside the mixing treatment tank, resulting in a problem that the yield decreases. It is also known that a laminar flow plate for adjusting the flow of the mixture is provided in the upper part of the mixing tank (Patent Document 1), but the particles only slide off as they are in the slip portion due to gravity, and are less likely to rotate. The same part of the particles comes into contact with each other, and there is a problem in that it is difficult to obtain a desired dispersed adhesion state.

  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. In the Henschel mixer, such a toner capable of fixing at a low temperature becomes more conspicuous in that the object to be processed is welded inside the stirring blade or the mixing processing tank and the yield is lowered. In addition, the toner has a small particle size of 3 to 10 μm for the purpose of high definition image and the toner has a spherical shape for the purpose of improving the transfer efficiency. For the purpose of uniform dispersion and adhesion, it is also known that the stirring blade (lower blade) in the Henschel mixer has high linearity (Patent Document 1). The problem still remains.

  Therefore, a method has been proposed in which the mixing tank is spherical and the toner base particles and external additive particles flow spirally upward at high speed along the tank inner wall, thereby enabling uniform external addition in a short time. (Patent Document 2, Patent Document 3). In this method, the contents rise up to the top of the treatment tank while rolling the tank wall in a spiral shape, and are then re-supplied to the stirring blades at the bottom of the tank. The up-and-down movement is more dynamic, and there is an advantage that it is not necessary to stir the flow by the two-stage blades.

  However, although the toner base particles having a high sphericity are excellent in rolling properties, the surface area is relatively smaller than that of the irregular toner, and the amount of external additives that are liberated due to less surface irregularities. In other words, 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. However, for toners that can be fixed at low temperature, increasing the stirring speed in the mixing tank will cause welding at the blade tips and inside the mixing tank, leading to 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.

  In order to give toner mother particles different functions such as charging and fluidity, a method of externally adding a plurality of types of external additive particles realizing different functions in multiple stages has been proposed. In the spherical mixing tank, the tip of the stirring blade rotating at high speed generates heat due to contact and friction between the toner base particles and the metal blade, and particularly when exposed to high-speed rotation for a long time, The particles become higher than the softening point of the resin, so that the external additive particles are easily embedded on the surface of the toner base particles, and the function of the external additive particles may be inhibited. Therefore, it is necessary to remove the heat without collecting the heat in the toner base particles by making the mixing tank a jacket type and circulating the cooling water. The higher the rotation speed, the higher the heat generated, the higher the need for heat removal, and the need for low-temperature cooling water. On average, this method can prevent the toner mother particles from significantly rising in temperature, but after the rotation is stopped, the cooling is conducted from the tank surface, so the vicinity of the inner surface of the tank and the central part Then, a temperature distribution will occur.

  In particular, in order to improve the properties of the toner, in the case where a plurality of external additives are added in multiple stages, there is no problem if the external addition prescription is completed in one stage. At the stage of completion, the flow of the content is stopped, and after the content that has risen is allowed to settle, the second-stage external additive particles are introduced. However, although it is cooled at the part in contact with the tank wall, since the contents contain air, the thermal conductivity is poor, the contents near the center of the tank remain in a high temperature state, and the temperature unevenness is Large, this phenomenon becomes more pronounced as the temperature of the cooling water is lower. The larger the temperature unevenness, the more easily the uneven adhesion of the external additive particles to the toner base particles occurs, and there is a problem that the increase in the reversely charged toner and the charge amount distribution (Q / m) cannot be made sharp. In particular, when metal soap particles having a low softening point are externally added at the end of the multistage external addition treatment step, the effect of temperature unevenness is large.

Therefore, although the method of cooling to the tank center part over a long time can be considered, it takes too much time, and productivity will be reduced remarkably. In addition, after the first external addition process, it is conceivable to mix the contents gently and average the temperature difference between the contents of the tank center and the contents near the tank wall. There is a problem that decreases.
JP-A-9-96923 Japanese Patent Laid-Open No. 8-173783 JP 2002-268277 A

  An object of the present invention is to provide a toner production method that can produce a toner having a small amount of positively charged toner and a sharp charge amount distribution in a high yield and in a short time.

  The toner manufacturing method of the present invention is a toner manufacturing method in which external additive particles are divided into multiple steps and externally added using a spherical mixing treatment tank having a water-cooled jacket on spherical resin particles containing at least a colorant. In the method, the spherical mixing treatment tank is spirally formed along the inner wall of the treatment tank with a horizontal disk-shaped tank bottom and a rotary drive shaft vertically passing through the center of the horizontal disk-shaped tank bottom. A stirring blade that discharges upward is attached, and a cylindrical member that vertically penetrates the top of the mixing treatment layer on the extension line of the rotary drive shaft is disposed so that the tip thereof is located in the mixing treatment tank, and the stirring blade The structure has a structure in which the object to be processed released upward in a spiral shape is moved to the top of the tank to reduce its kinetic energy, and the object to be processed is re-supplied to the stirring blade at the bottom of the tank. External processing after the second stage in When the temperature of the object near the tank wall cooled by the water cooling jacket after the first external addition treatment is higher than the temperature of the object near the tank wall before the first external addition treatment, the second and subsequent stages The external additive particles in are added, and the external addition process in the second and subsequent stages is started.

  The spherical resin particles have a shape factor (ML2 / A) of 1.05-1.40, a shape factor (PM2 / A) of 1.05-1.30, and a flow softening point (Tf1 / 2). Is 100 to 130 ° C.

  The external additive particles are selected from at least hydrophobized silica fine particles, titanium oxide fine particles, particles composed of long-chain fatty acids or salts thereof, and finally particles composed of long-chain fatty acids or salts thereof are externally added in the multistage external treatment. It is characterized by being processed.

  The toner manufacturing method of the present invention is suitable for external addition processing of toner base particles having a spherical shape and a low flow softening point, and has a small amount of free external additive and positively charged toner, and a toner having a sharp charge amount distribution. It can be manufactured in a short time with a high recovery rate.

  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.

  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 the external additive from the toner base particles. Particles are easy to peel off and uniform adhesion is difficult, so the peripheral speed of the stirring blade must be increased, and toner mother particles are welded to the blade tip and tank wall, resulting in a decrease in yield. The amount of free external additive and the amount of positively charged toner also increase, 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 copolymers. Polymer (ACS resin), styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene crosslinked polymer, styrene-butadiene-chlorinated paraffin copolymer, styrene-allyl alcohol copolymer, styrene -Butadiene rubber, styrene-maleic acid ester copolymer, styrene-isobutylene copolymer, styrene-maleic anhydride copolymer and the like.

  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.

  The 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, 2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexatricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) Examples include methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, and lower alkyl esters or acid anhydrides thereof.

  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 (Hansaero A), CI11740 (Hansaero NR), CI12710 (HansaEro R), CI12720 (Pigment Yellow L), CI21090 (Benzidine Eros G), CI21095 (Benzidine Eros G), CI21100 (Benzines Eros 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 Oils & 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 (made by)) is exemplified.

  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.

  Moreover, you may add metal soap, polyethyleneglycol, etc. as a dispersing agent.

  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 (manufactured by Orient Chemical Co., Ltd.), thioindigo pigment, sulfonylamine derivative of copper phthalocyanine, Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.), Bontron S-34 (manufactured by Orient Chemical Co., Ltd.) ), Nigrosine SO (manufactured by Orient Chemical 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 Fabricken 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, and Ni, or metal alloy powders such as Cr, Mn, and Zn, composites such as Fe ₃ O ₄ , Fe ₂ O ₃ , Cr ₂ O ₃ , and various ferrites. An alloy exhibiting ferromagnetism or the like by heat treatment such as a metal oxide or an alloy containing manganese and an acid may be added, and those previously treated with a coupling agent or the like may be used.

  The toner base particles may be any of toner base particles obtained by a pulverization method, a dissolution suspension method, or a polymerization method. 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.

  In addition, the dissolution suspension method toner is prepared by dissolving the above-described binder resin and the internal additive such as a colorant and a release agent in an organic solvent, and then dispersing and granulating it in a water phase together with a dispersant and an emulsifier. The toner base particles are obtained by separating and drying. Although the spherical toner base particles are obtained by the dissolution suspension method, the sphericity can be appropriately adjusted by heat-deforming at a temperature equal to or higher than the Tg temperature of the toner base particles.

  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 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.

  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.

  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, 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, and the binder resin containing the crystalline polyester resin described in Japanese Patent Application Nos. 2003-293707, 2003-293708, and 2003-293709 may be used. Illustrated.

  The weight average molecular weight of the binder resin is 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 sufficiently performed, and the saturation or transparency of the obtained toner may be lowered. If 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 in the case of a pulverized toner, the viscosity becomes too high, and the colorant Dispersion cannot be performed sufficiently, and the saturation or transparency of the toner may decrease. 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 in the present invention is a value measured with a particle image analyzer (FPIA2100 manufactured by Sysmex).

  As a method for adjusting the sphericity, 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. In the dissolution suspension method, the sphericity can be appropriately adjusted by heating and deforming at a temperature equal to or higher than the Tg temperature of the toner base particles.

  The external additive particles in the present invention will be described. First, negatively charged or positively charged silica fine particles that have been subjected to a hydrophobic treatment are exemplified.

  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. 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 silica having a small particle size, and negative particles having an average particle size of 20 to 200 nm, preferably 20 to 110 nm, as silica having a large particle size. 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 using large particle size silica and small particle size silica, 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. 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 Co., and Seahorster KEP10 manufactured by Nippon Shokubai Co., Ltd. Illustrated.

  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 external additive particles in the present invention, fine particles of titanium oxide having a relatively low electrical resistivity are added in addition to silica fine particles subjected to 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 microparticles | fine-particles, it is preferable that a particle size or a length of a major axis is a magnitude | size of 10-200 nm. In the case of rutile-anatase-type titanium oxide, titanium oxide fine particles having a major axis of about 10 to 200 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 preferable. 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 10-300 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 the toner production method of the present invention, the toner base particles and the inorganic external additive particles described above are mixed, and then the processed product and the long-chain fatty acid or salt thereof are mixed as the external additive particles. May be. 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 particulate long-chain fatty acid or salt thereof, particularly long-chain fatty acid metal salt (metal soap) particles have a volume average particle diameter or a major axis diameter of 0.1 to 10 μm, 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 occur.

  The mixing order when the above-described various external additive particles are mixed with the toner base particles will be described.

  (A) First, when the toner base particles are positive to weakly negatively chargeable during multi-stage processing, the external additive added first is (1) negatively chargeable silica fine particles, and (2) negatively chargeable silica fine particles. And titanium oxide fine particles or (3) titanium oxide fine particles. Hereinafter, (1) to (3) will be described.

  (1) When negatively chargeable silica fine particles are added alone, the electrostatic attractive force between the toner base particles and the negatively chargeable silica fine particles is not obstructed by the positively chargeable silica fine particles. The silica fine particles can be strongly adhered to the toner base particles. As a result, the desorption of the negatively chargeable silica fine particles is prevented, the change in chargeability is reduced, and the effect that the chargeability is stabilized in the long term is obtained. In addition, the negative chargeable silica fine particles can be used in combination with a small particle size silica and a large particle size silica to increase the absolute value of the charge amount, to obtain long-term charge stability, and toner fluidity. This is preferable from the standpoint of improving toner and exhibiting a heat blocking effect to improve the storage stability of the toner.

  When the negatively chargeable silica fine particles are added first, the titanium oxide fine particles and the positively chargeable silica fine particles are then added. Although the titanium oxide fine particles and the positively chargeable silica fine particles may be added simultaneously, it is more preferable to add the titanium oxide first, and then add the positively chargeable silica. The positively chargeable silica fine particles are positively charged and have a high electric resistance value. Therefore, by adding the titanium oxide fine particles and then adding the positively chargeable silica fine particles, the positively chargeable silica fine particles (so-called “microcarriers”) function as a charge adjusting agent, thereby speeding up charging. , The charge is made uniform.

  Four-stage treatment in which positively charged silica fine particles are added singly to toner base particles added in the order of negatively chargeable silica fine particles-titanium oxide fine particles, and finally particles comprising a long-chain fatty acid or a salt thereof are added, or There is a three-stage process in which positively-charged silica fine particles and particles of a long-chain fatty acid or a salt thereof are added simultaneously to form the final stage. Further, a two-stage treatment in which titanium oxide fine particles, positively charged silica fine particles, and particles of a long chain fatty acid or a salt thereof are simultaneously added to the negatively chargeable silica fine particles may be employed. Among these, positively-charged silica fine particles and particles of long chain fatty acids or salts thereof are added at the same time, and the three-stage treatment is performed to adjust the surface charge by the positively-charged silica fine particles and the titanium oxide fine particles and to reduce the electric resistance. It is preferable in that it can be most efficiently performed without extremely reducing.

  Examples of the multi-stage treatment in which the negatively charged silica fine particles are added first and at least the long-chain saturated fatty acid or the salt thereof is finally added include the following multi-stage treatments (a) to (f). .

(A) Negatively chargeable silica fine particles-titanium oxide fine particles-positively chargeable silica fine particles-long chain saturated fatty acid or salt thereof (b) Negatively chargeable silica fine particles-titanium oxide fine particles- (positively chargeable silica fine particles + long chain saturated fatty acid) Or its salt)
(C) Negatively chargeable silica fine particle-titanium oxide fine particle-long chain saturated fatty acid or salt thereof (d) Negatively chargeable silica fine particle- (titanium oxide fine particle + long chain saturated fatty acid or salt thereof) (e) Negatively chargeable silica fine particle -(Titanium oxide fine particles + positively charged silica fine particles + long chain saturated fatty acid or salt thereof)
(F) Negative chargeable silica fine particles-positive chargeable silica fine particles-long chain saturated fatty acid or salt thereof in this order.

  The toner obtained by adding the negatively charged toner fine particles first, and finally adding the long chain fatty acid or salt thereof, in addition to the effects such as strong adhesion of the negatively charged silica fine particles to the toner base particles, Since the effect of adding a long-chain fatty acid or a salt thereof is exerted, the release of silica fine particles is controlled and uniform chargeability is achieved as compared with the toner obtained by performing the external addition treatment once in the past. It has excellent properties such as being maintained for a long time.

  (2) First, negatively chargeable silica fine particles and titanium oxide fine particles may be simultaneously added to the toner base particles. Next, by adding a long-chain fatty acid or a salt thereof, liberation of inorganic external additive particles is suppressed.

As such multistage processing,
(G) (Negatively chargeable silica fine particles + titanium oxide fine particles) -Positively chargeable silica fine particles-Long chain saturated fatty acid or salt thereof (h) (Negatively chargeable silica fine particles + titanium oxide fine particles)-(Positively chargeable silica fine particles + Long chain saturated fatty acids or salts thereof)
It is each order.

  (3) When adding titanium oxide fine particles first, it is preferable to add negatively chargeable silica fine particles. Next, if necessary, by adding the positively chargeable silica fine particles before the long chain fatty acid or salt thereof or simultaneously with the long chain fatty acid or salt thereof, while preventing a rapid decrease in the charge amount, The charge amount can be adjusted. In addition to this effect, the effect of the long-chain fatty acid or salt thereof is exhibited.

As such multistage processing,
(I) Titanium oxide fine particles-negatively chargeable silica fine particles-positively chargeable silica fine particles-long chain saturated fatty acid or a salt thereof (j) Titanium oxide fine particles-negatively chargeable silica fine particles- (positively chargeable silica fine particles + long chain saturated fatty acid) Or its salt)
(K) Titanium oxide fine particles-negatively chargeable silica fine particles-long chain saturated fatty acid or a salt thereof in this order.

  (B) When the toner base particles are strongly negatively charged, the toner base particles preferably have a charge amount of −5 to −60 μC / g. In the multi-stage treatment of the negatively chargeable toner base particles, negatively chargeable silica fine particles are generally not used. However, when the degree of negative charge is weak, the negatively chargeable silica fine particles may be added for charge adjustment. The external additive is generally added so that the charge amount of the obtained toner is −5 to −30 μC / g.

  When using negatively chargeable toner base particles, (1) First, positively charged silica particles are added, (2) First, positively charged silica particles and other external additives are added, (3) First oxidized A multi-stage treatment such as adding titanium fine particles can be mentioned.

  (1) It is most preferable to add positively charged silica fine particles alone first. According to this step, the electrostatic attractive force between the negatively chargeable toner base particles and the positively chargeable silica fine particles is not hindered, and the positively chargeable silica fine particles are strongly attached to the toner base particles. Therefore, the positively chargeable silica fine particles are prevented from being detached, the change in chargeability is reduced, and the effect that the chargeability is stabilized for a long time is obtained.

  After the addition of the positively chargeable silica fine particles, the titanium oxide fine particles are added alone or together with the particles made of long chain fatty acid or a salt thereof. By externally adding positively-charged silica fine particles having a high electrical resistance value in advance, the surface charge when titanium oxide having low electrical resistance is externally added is not greatly reduced (ie, positively charged). The fine silica particles function as a charge adjusting agent), and the reduction in the electrical resistivity of the toner is suppressed, and the charge is made uniform. In addition to these effects, the effect of adding a long-chain fatty acid or a salt thereof at the end is exhibited.

As such multistage processing,
(L) Positively chargeable silica fine particles-long chain fatty acid or salt thereof (m) Positively chargeable silica fine particles-(titanium oxide fine particles + long chain fatty acid or salt thereof)
Each order is illustrated.

  This multi-stage treatment does not include negatively chargeable silica fine particles as an external additive. A toner containing no negatively chargeable silica fine particles as an external additive has good charging characteristics and fluidity. In addition, the toner fixing temperature can be lowered (the temperature of the fixing device can be set low), and the fixing strength of the image after fixing can be improved.

(2) In a toner obtained by first adding positively chargeable silica fine particles and other external additives, when the other external additive is negatively chargeable silica fine particles, the toner base particles are negatively charged. In view of the above, it is preferable from the viewpoint of charge control that it is added first at the same time as the positively chargeable silica fine particles. As an example of multi-stage treatment in which positively charged silica fine particles and negatively charged silica are added first,
(N) (positively charged silica fine particles + negatively chargeable silica fine particles) -titanium oxide-long chain fatty acid or salt thereof)
(O) (positively charged silica fine particles + negatively charged silica fine particles + titanium oxide) -long chain fatty acid or salt thereof (p) (positively charged silica fine particles + negatively charged silica fine particle) -long chain fatty acid or salt thereof Each order is illustrated. In (p), titanium oxide fine particles are not added, but if the charge amount is in an appropriate range, it may not be added.

(3) Titanium oxide fine particles may be added first. For example, the following multistage treatment (q) Titanium oxide fine particles-negatively charged silica fine particles-positively charged silica fine particles-long chain fatty acid or salt thereof (r) Titanium oxide Fine particles-Negatively chargeable silica fine particles-(Positively chargeable silica fine particles + long chain fatty acids or salts thereof)
Each order is illustrated.

  The order of the multi-stage processes (a) to (r) is merely an example, and is not limited to these. Moreover, you may add inorganic fine particles other than the above-mentioned titanium oxide for the purpose of charge adjustment, fluidity | liquidity improvement, etc. as needed. The inorganic fine particles may be added at any stage as long as it is before or simultaneously with the addition of the long-chain fatty acid or salt thereof.

The average charge amount of the toner particles to which the external additive particles are attached is preferably -5 to -30 [mu] C / 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. Temperature 25 ° C., under an environment of 45% RH, put the toner to the developing device of LP-9000C (manufactured by Seiko Epson Corporation), developing device after idling, on the surface of the developing roller of 0.3 kg / cm ² Nitrogen gas at a 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 Corporation. The charge amount (Q / m) of the toner Measure.

  Next, a manufacturing apparatus used in the toner manufacturing method 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 to 3 is used. FIG. 1 is a central sectional view, FIG. 2 is a plan view showing an example of a mixing blade, and FIG. 3 is a view showing a state in which the upper hemisphere portion of the mixed treatment layer is opened from the flange portion 8 and viewed from the inside. In the figure, 1 is a spherical mixing treatment tank, 2 is a horizontal disk-shaped tank bottom, 3 is a rotary drive shaft, 4 is a donut disk, 5 is a stirring blade, 6 is an air seal hole, 7 is a cylindrical member, 8 is A flange, 9 is a water-cooled jacket, 11 is a stirring blade, 12 is a workpiece flow regulating plate, 13 is an attachment member, and 14 is a thermocouple.

  As shown in FIGS. 1 and 2, the spherical mixing treatment tank 1 is provided with a horizontal disk-shaped tank bottom 2 and a stirring blade 11 having a conical section on a rotary drive shaft 3 that vertically penetrates the center of the tank bottom 2. In addition, a plurality of stirring blades 5 are respectively attached on the outer peripheral end portion. The stirring blade 11 is a turbine blade, and the shearing action by the blade is relatively small, so that the mixing can proceed in a state where the dispersibility is reduced. In addition, a donut disk 4 for reinforcement is attached to the upper part of the stirring blade 5.

  At the top of the container 1, a cylindrical member 7 that penetrates the top of the mixing treatment tank on the extension line of the rotary drive shaft 3 is arranged so that the front end of the tank is located in the upper hemisphere, and the seal air can be removed. The workpiece flow restriction plate 12 is attached via the attachment member 13. The upper hemisphere in the mixed treatment layer can be opened and closed from the flange 8 at the center, and the workpiece is introduced by opening the upper hemisphere. The charged object to be processed is spirally (not shown) along the inner wall surface of the processing tank 1 due to the centrifugal force generated by the rotation of the stirring blade 11 and discharged upward as shown by the arrows in FIG. Drop with reduced kinetic energy. The dropped processing object slides down the conical upper surface and is re-supplied to the stirring blade 5. By repeating this process, dispersion mixing proceeds. A discharge port (not shown) for an object to be processed after external addition is provided in the lower part of the processing tank 1. Further, the spherical mixing treatment tank is provided with a water cooling jacket 9, and the contents can be cooled by passing cooling water having a water temperature described later at a flow rate described later.

  A stirring blade 11 is rotatably attached to the rotary drive shaft 3 through a seal air hole 6, and the tip of the stirring blade 5 is connected to the outer periphery of the donut disk 4 and the inner wall of the tank as shown in FIGS. 1 and 2. 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 rotated along the curved surface of the inner surface of the processing tank by rotating. It is set as the shape which can discharge | release spirally toward a processing tank top part. The seal air hole 6 is an air supply hole for preventing the object to be processed from entering the rotary drive shaft portion that becomes 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.

  The ratio between the diameter of the horizontal disk-shaped tank bottom 2 and the diameter of the treatment tank 1 is 0.25 to 0.80, and the ratio between the outer diameter of the donut-shaped disk 4 and 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 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. When the content is large, an external additive may be introduced using the cylindrical member 7 as an inlet.

  As in the Henschel mixer shown in FIG. 4, the spherical mixing treatment tank does not cause the object to be treated to rise abruptly. Instead, the toner mother particles and external additive particles that are the object to be treated are placed along the curved tank wall. In addition, it is possible to flow at a high speed, and the wall surface distance through which the material to be processed flows is long, and the toner base particles are easy to roll, enabling uniform external addition processing in a short time. In addition, since the object to be processed reduces the kinetic energy at the top of the mixing treatment tank, falls, and is re-supplied to the stirring blades at the bottom of the tank, the vertical movement of the object to be treated, which depends on gravity like a Henschel mixer, is prevented. Become more dynamic. Moreover, it has the advantage that it is not necessary to provide an upper blade | wing. In addition, when the aggregation of the external additive particles is strong, it is possible to provide a convex portion in the tank to generate a turbulent flow and disintegrate.

  As shown in FIG. 1, the workpiece flow regulating plate 12 is a support member so that the workpiece to be lifted while spirally flowing on the inner wall surface of the tank is moved in the direction of the rotation axis of the rotation drive shaft. 13 is attached. In the direction opposite to the rotation axis direction of the rotation drive shaft, the flow of the fluidized bed is greatly disturbed, leading to a temperature rise of the object to be processed, and unevenness of the adhesion of the external additive particles occurs. Moreover, as shown in FIG. 1, the to-be-processed object flow control board 12 is good to install in a cylindrical member in an upper hemisphere via an attachment member. In the lower hemisphere, the object to be processed just discharged from the stirring blades is immediately turbulent, and unevenness occurs on the toner base particles.

  The workpiece flow regulating plate 12 has a top edge a shape corresponding to the shape of the inner wall of the upper hemisphere in the mixing treatment tank, and has a fan-shaped surface A that regulates the flow of the workpiece in the direction of the rotation drive shaft 3. As shown in FIG. 3, the mounting angle is a direction in which the fan-shaped surface A is perpendicularly opposed to the direction in which the workpiece discharged spirally upward along the inner wall of the processing tank flows (the dotted line direction in FIG. 3). ) Is set to 0 °, and is opposed to the direction in which the workpiece flows in an angle range of θ, and the flow direction of the workpiece is the rotational axis direction of the rotary drive shaft 3 and is a cylindrical member It is good to attach so that it may regulate in the downward direction. It is not preferable to restrict the flow in the direction of the cylindrical member because deposition of an object to be processed occurs. The angle θ may be greater than 0 ° and 90 ° or less, and preferably 20 to 60 °. If θ is out of the range, the vertical movement of the workpiece is hindered.

  The object flow regulating plate is intended to make the laminar flow state of the fluidized bed partly turbulent, and is the closest gap between the upper edge a of the fan-shaped surface and the inner wall b of the upper hemisphere in the mixing treatment tank. The distance is 1 mm to 30 mm, preferably 1.5 mm to 25 mm, although it depends on the thickness of the fluidized layer on the inner wall surface formed by the centrifugal force of the object to be treated, particularly resin particles. If it is less than 1 mm, the resin particles stay on the material flow regulating plate 12 to generate resin particles that do not move or resin particles that are not externally added. If it exceeds 30 mm, the effect of turbulent flow cannot be sufficiently obtained. Further, the gap (interval) between the upper end edge a ′ on the cylindrical member side on the fan-shaped surface A and the upper hemisphere inner wall b ′ is defined as the gap between the upper end edge a ″ on the opposite side to the cylindrical member and the upper hemisphere inner wall b ″. The gap between the upper end edge a ′ on the cylindrical member side and the upper hemisphere inner wall b ′ is preferably at least 2 mm or more, preferably 5 mm or more. Even if the workpiece flow regulating plate is arranged at the top of the mixing treatment tank, the retention of the workpiece can be prevented.

Further, the arc length (L ₁ ) of the upper edge a of the fan-shaped surface A in the workpiece flow regulating plate 12 may be adjusted according to the attachment angle of the workpiece flow regulating plate. The circumference is 1/10 to 1/4, preferably 1/8 to 1/5, and if it is less than 1/10, the effect of generating turbulence is small. Beyond that, turbulence becomes too large.

In addition, the width (L ₂ ) of the fan-shaped surface A in the workpiece flow regulating plate may be equal to or greater than the thickness of the fluidized bed on the inner wall surface formed by centrifugal force of the workpiece, particularly the resin particles. The radius is 1/10 to 1/1, preferably 1/5 to 1/3 of the radius when the surface is a sphere. When the width (L ₂ ) of the fan-shaped surface A is less than 1/10, when the processing amount is large, the workpiece flow regulating plate is buried in the fluidized bed, and the effect of generating turbulence cannot be obtained. . If the radius is greater than or equal to the radius, the inside of the restricting plate will oppose the direction of the fluidized bed, the occurrence of turbulence is too great and damage to the resin particles is large, and the vertical movement of the workpiece is hindered. Therefore, it is not preferable.

  The attachment position of the workpiece flow regulating plate to the cylindrical member and the length of the attachment member may be appropriately adjusted so as to obtain the above-described fan-shaped surface arrangement. Further, the material flow regulating plate 12 is exemplified by a SUS304 plate as a material, and a thickness of 2 mm to 10 mm is preferable.

  By providing the workpiece flow regulating plate 12, the flow of resin particles having high fluidity can be disturbed and uniformly dispersed and mixed with external additive particles in a shorter time, so that the charge amount distribution can be made uniform. In addition, the amount (number%) of free external additive particles can be reduced, and the amount of toner having a reverse polarity can be reduced. Further, the amount (number%) of free toner base particles can be reduced, the amount of resin particles adhering to the curved portion (R portion) and the stirring blade is reduced, and the yield can be improved.

  Next, a case where multistage external addition processing is performed using a spherical processing tank that characterizes the present invention will be described.

  In the multi-stage external addition process, the toner base particles are introduced into the spherical mixing tank, and then the external additive particles to be externally added first (first stage) are added and mixed, whereby the external additive is added to the toner base particles. After attaching the particles, stop the rotation, stop the air seal, then open the upper hemisphere from the flange part, add the external additive particles to be added externally in the second stage, mix and process the second stage external additive After further adhering the particles, the rotation is stopped, the air seal is stopped, and this operation is repeated for the third and subsequent stages to perform external addition processing in multiple stages, which is an operation consisting of at least two stages of external addition processing. . Thereby, the function by the external additive particle | grains from which a kind and a particle diameter differ can be exhibited effectively, respectively. In each stage, rotation and stop may be repeated a plurality of times in order to control the temperature rise of the workpiece.

  In the toner manufacturing method of the present invention, the external addition process in the second and subsequent stages is performed in such a manner that the temperature of the object to be processed near the tank wall cooled by the water cooling jacket after the first external addition process is the tank before the first external addition process. The external additive particles in the second and subsequent stages are charged when the temperature is higher than the temperature of the object to be processed near the wall, and the external addition process in the second and subsequent stages is started, although the average processing temperature is high, The temperature difference between the contents in the vicinity of the tank wall and the contents in the center of the tank can be reduced, and the temperature unevenness can be reduced, thereby reducing the unevenness of adhesion of the external additive particles and the processing time. Can be shortened and productivity can be improved.

  The thermocouple 14 in FIG. 1 is provided for monitoring the temperature of the contents in the vicinity of the inner wall of the tank, and does not hinder the flow of contents on the tank wall in the lower hemisphere of the spherical mixing treatment tank (in the tank About 1.5 mm) and protrudes into the tank.

  An example of the temperature change measured by the thermocouple in the multistage process is shown in FIG. (A) is a figure for demonstrating the condition of the temperature change in this invention, (b) is a figure for demonstrating the condition in a comparative example. As shown in FIG. 5, the object to be processed is normally charged at room temperature (25 ° C.), and thus shows the room temperature (25 ° C.) before the processing. However, as the mixing process proceeds, the temperature rises due to frictional heat generation. Is observed, and the maximum temperature rises from 27 ° C. to about 32 ° C. At the same time as the mixing process is stopped, the flow of the contents stops, and the contents are cooled by the cooling effect of the low-temperature cooling water.

  The temperature, flow rate, and standby time of the cooling water in the water cooling jacket are appropriately set, but the cooling water flowing through the water cooling jacket is a water temperature that is 2-10 ° C. lower than the temperature in the contents before treatment, 10-50 liters / min. A good guideline is In addition, the waiting time until the upper hemisphere is opened to add the second and subsequent external additive particles must be at least several tens of seconds until the contents settle down. The mixing process is stopped and the sealing air is stopped. After that, it is about 1 to 7 minutes. If the temperature of the cooling water is too low or the waiting time is too long, the temperature difference between the temperature of the object at the center of the tank and the object near the inner wall of the tank will become too large, resulting in temperature irregularities, and consequently external additives. This is not preferable because it causes uneven adhesion of particles. Moreover, if the opening is too early, the powder may not yet settle, the seal air may not escape, the powder will rise and scatter, and the ratio of the external additive may change from the desired ratio.

  Ideally, if the second stage can be input immediately after the completion of the first stage, temperature unevenness may not occur. However, the tank must be opened for the input, and a certain amount of powder may be prevented in order to prevent powder scattering at that time. Time is needed and impossible. It was found that the temperature unevenness with the central portion of the tank was the largest when the temperature unevenness was waited until the temperature in the vicinity of the tank wall became the same as that at the time of charging. Therefore, the temperature of the object in the vicinity of the inner wall of the mixing tank, which is a measure of the timing of charging the second-stage external additive particles, should be higher than the temperature before the treatment, and the upper limit is the maximum temperature during the mixing treatment. However, in order to reduce the temperature unevenness and obtain a cooling effect on the toner base particles, it is preferable to set the temperature range higher than the temperature before the first external addition treatment by 0.5 ° C. or more and lower than the maximum temperature. . The temperature of the object to be processed in the vicinity of the inner wall of the mixing tank, which serves as a reference for the timing of adding the external additive particles after the third stage, may be higher than the temperature before the first external addition process.

  Moreover, if the mixing process time in each stage is short, the mixing process becomes insufficient, and if the mixing process time is long, the material to be processed is welded to the tank wall, the stirring blade, etc., and the yield decreases. One treatment time is 0.5 to 10 minutes, preferably 1 to 5 minutes. In addition, if the stirring speed is low, the mixing process becomes insufficient, and if the stirring speed is high, the object to be processed is welded to the tank wall or the stirring blade, resulting in a decrease in yield. The peripheral speed (π × outer diameter of blade × rotational speed / hour) at the tip of the stirring blade is preferably in the range of 10 m / s to 100 m / s.

  In the toner manufacturing method of the present invention, when multiple types of external additive particles are added to the toner base particles in a multi-stage external addition process, they can be uniformly attached in a shorter time, so that the charge amount distribution can be made uniform. In addition, the amount (number%) of free external additive particles can be reduced, and the amount of toner having a reverse polarity can be reduced. Further, the amount (number%) of free toner base particles can be reduced, the amount of resin particles adhering to the curved portion (R portion) and the stirring blade is reduced, and the yield can be improved.

  The toner thus obtained has a volume average particle size of 3 to 9 μm, preferably 3 to 8 μm. Even if toner particles larger than 9 μm form a latent image 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 to the decrease, the amount of the external additive used for increasing the fluidity increases, and as a result, the fixing performance tends to decrease. The volume average particle diameter of the toner is a value measured by a flow type particle image analyzer (FPIA2100 manufactured by Sysmex).

  The amount (number%) of free toner base particles and free inorganic external additive particles is measured using a particle analyzer (“PT1000” manufactured by Yokogawa Electric Corporation) with the total number of measurements being around 5000. The number of detected Si and Ti elements (free inorganic external additive particles) not synchronized with the carbon atoms (toner base particles) of the toner particles introduced into the plasma flame with He gas is measured. The respective free rate (number%) is calculated. The state of adhering to the toner base particles is detected as the synchronous number.

Free silica (number%)
= Number of asynchronous Si / (number of asynchronous Si + number of synchronous Si) × 100
Free titania (number%)
= Asynchronous Ti number / (asynchronous Ti number + synchronous Ti number) × 100
Free toner base particles (number%)
= Asynchronous C number / (asynchronous C number + Si-C synchronous C number) × 100
According to the method for producing a toner of the present invention, in the obtained toner, the liberation rate of the inorganic external additive particles can be 1 to 10% by number, preferably 1 to 5% by number. The amount of toner can be reduced and the toner can have a uniform charge distribution, and the OD value when applied to non-contact development is high and the durability of a large number of sheets can be improved. When the liberation rate of inorganic external additive particles is more than 10% by number, the amount of positively charged toner increases, the charge distribution is not sharp, the fog is large, and the OD value when applied to non-contact development is low. Also, the durability of a large number of sheets is inferior.

  Further, when the amount of the free toner base particles is 40% by number or less, uniform external addition can be achieved, and the production method can be made with a high yield with less fusion to the apparatus.

  The toner of the present invention has a shape factor (ML2 / A) measured in the same manner as described above of 1.05-1.40, preferably 1.05-1.30, and a shape factor (PM2 / A). 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), and a toner having excellent transferability can be obtained. The toner of the present invention has a flow softening point (Tf1 / 2) of 100 to 130 ° C, preferably 100 to 120 ° C, and a glass transition temperature (Tg) of 50 to 100 ° C, preferably 60 to 90 ° C. In other words, it is a so-called “low temperature fixable toner” that can be fixed under hot pressure conditions (140 to 200 ° C., linear pressure 0.04 to 0.1 kgf / mm) in the fixing step.

  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 toner produced in the present invention can be applied to any one of image forming apparatuses using a one-component or two-component toner described in detail in JP-A-2002-202622. The toner can be applied to both an image forming apparatus and a non-contact developing type image forming apparatus, but can be a toner suitable for application to an image forming apparatus having a non-contact developing type.

  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 carried out 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 7 parts by mass of phthalocyanine blue were used as surfactants, and 0.2 part by mass of sodium dodecylbenzenesulfonate was included. 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 further vacuum dried at 45 ° C. for 10 hours while adding 0.5% by mass of silica fine particles (primary particle size 40 nm) to obtain toner mother particles.

  The average particle diameter of the 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.

  A spherical mixing tank (made by Mitsui Mining Co., Ltd., Q-type mixer 20L type, a stirring blade is a turbine blade, and a jacket with a water temperature As a first-stage external addition process, water at 20 ° C. is passed through at a rate of 20 liters / min., And the rotating shaft is cooled with water and has a structure for preventing intrusion of an object to be processed with seal air). Silica fine particles {RX200 (average particle size 12 nm) manufactured by Nippon Aerosil Co., Ltd.) and silica powder {RX50 (average particle size 40 nm) manufactured by Nippon Aerosil Co., Ltd. It added in the ratio of the mass%, and the external addition process was carried out on the following conditions. The temperature (thermocouple) of the workpiece was 25.0 ° C.

  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.

Further, the ratio of the width (L ₂ ) of the workpiece flow regulating plate to the radius on the inner wall surface side of the tank is 0.2, the ratio of the length (L ₁ ) to the peripheral length on the inner wall surface side is 0.2, θ = 60 °, the distance of the shortest gap between the upper end of the fan-shaped surface of the workpiece flow regulating plate and the inner wall of the tank is 3 mm, and the interval (gap) on the cylindrical member side at the upper end of the fan-shaped surface is 25 mm.

This spherical mixing treatment tank was mixed with a seal air amount of 1.0 Nm ³ / h, a turbine blade peripheral speed of 50 m / s, and a mixing time of 3 minutes. The peripheral speed of the turbine blade was calculated from the outermost diameter of the blade and the rotational speed. The maximum temperature at the first stage was 28.1 ° C.

  After the first-stage mixing process is completed, the rotation stops, the seal air is turned off, wait for 2 minutes, and when the thermocouple shows 26.2 ° C., oxidation is performed as the second-stage external addition process. Titanium fine particles {manufactured by Titanium Industry Co., Ltd., STT30S (average particle size 30 nm)} are added at a rate of 0.5 mass% with respect to the toner base particles, the peripheral speed of the turbine blade is 50 m / s, and the mixing time is 3 Mixing was performed in the same manner as in the first stage for a minute. The maximum temperature at the second stage was 29.3 ° C.

  After completion of the second stage mixing process, the process waited for 2 minutes, and at the stage where the thermocouple showed 27.0 ° C., as the third stage external addition process, zinc stearate particles {manufactured by NOF Corporation, MZ2 (average particle size 0.9 μm)} is added at a ratio of 0.1% by mass with respect to the toner base particles, the peripheral speed of the turbine blade is 50 m / s, the mixing time is 3 minutes, and the first stage. Mixing treatment was performed in the same manner. The maximum temperature at the third stage was 30.0 ° C.

  FIG. 5A shows an explanatory diagram of the temperature change of the object to be processed in the vicinity of the inner wall of the tank during the mixing process in the first stage, the second stage, and the third stage, and the waiting time.

  The ratio (yield) of the recovered weight to the input weight of the object to be processed was 97.5%. Regarding the obtained toner, the number release rate of silica fine particles was 0.7% by number, the number release rate of titania fine particles was 3.7% by number, and the amount of free toner base particles was 27.4% by number. It was.

  Next, the obtained toner was loaded into a toner cartridge of a color printer (“LP9000C” 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 3.2% by number, and the standard deviation (μC / g) of the ratio (Q / m) between the charge amount and the mass determined from the particle diameter was 8.5.

  A uniform external addition process with a high recovery rate, a small amount of free external additive and a positively charged toner, and a narrow charge amount distribution could be performed in a short time.

  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.

  25.0 kg of the obtained toner mother particles were added to a spherical mixing tank (Mitsui Mining Co., Ltd., Q-type 150 L, a stirring blade was a turbine blade, and a jacket having a water temperature of 20 ° C. was attached. Water is passed at 30 liters / min., And the rotating shaft is cooled with water, and is loaded into a processing object with seal air to prevent intrusion of the object to be processed. A 1: 1 (mass ratio) mixed powder of RX200 (average particle size 12 nm) manufactured by Nippon Aerosil Co., Ltd. and silica fine particles {RX50 manufactured by Nippon Aerosil Co. Ltd. (average particle size 40 nm) is 1.5% by mass with respect to the toner base particles. They were added in proportions and externally added under the following conditions. The temperature (thermocouple) of the workpiece was 25.0 ° C.

The shapes of the spherical mixing tank and the workpiece flow regulating plate are the same as those in the first embodiment. This spherical mixing treatment tank was 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 3 minutes. The maximum temperature at the first stage was 29.4 ° C.

  After completion of the first stage of the mixing process, the process waited for 4 minutes, and at the stage where the thermocouple showed 27.3 ° C., as the second stage of external addition process, titanium oxide fine particles {manufactured by Titanium Industry Co., Ltd., STT30S (average Particle diameter 30 nm)} was added at a ratio of 0.5 mass% with respect to the toner base particles, the peripheral speed of the turbine blade was 60 m / s, the mixing time was 3 minutes, and the mixing treatment was performed in the same manner as in the first stage. . The maximum temperature at the second stage was 31.2 ° C.

  After completion of the second stage mixing process, the process waited for 4 minutes, and at the stage where the thermocouple showed 27.9 ° C., as the third stage external addition process, zinc stearate particles {manufactured by NOF Corporation, MZ2 (average particle size 0.9 μm)} is added at a ratio of 0.1% by mass with respect to the toner base particles, the peripheral speed of the turbine blade is 60 m / s, the mixing time is 3 minutes, and the first stage. Mixing treatment was performed in the same manner. The maximum temperature at the third stage was 32.0 ° C.

  The ratio (yield) of the recovered weight to the input weight of the object to be processed was 97.6%. Regarding the obtained toner, the number release rate of silica fine particles was 1.5% by number, the number release rate of titania fine particles was 3.2% by number, and the amount of free toner base particles was 28.9% by number. .

  Further, when the charge amount distribution of the toner on the developing roller was measured in the same manner as in Example 1, the positively charged toner amount was 6.1% by number, and the ratio between the charge amount and the mass determined from the particle diameter ( The standard deviation (μC / g) of Q / m was 9.5.

  A uniform external addition process with a high recovery rate, a small amount of free external additive and a positively charged toner, and a narrow charge amount distribution could be performed in a short time.

  In the production of the toner base particles of Example 1, the wax emulsion was adjusted to 10 parts by mass and the temperature and time were adjusted in the aggregation process of the secondary particles to obtain an average particle diameter of 7.5 μm, a flow softening point (Tf1 / 2). The toner base particles were 128.2 ° C., ML2 / A was 1.30, and PM2 / A was 1.25.

  2.8 kg of the obtained toner mother particles were added to a spherical mixing tank (Mitsui Mining Co., Ltd., Q type 20L, a stirring blade was a turbine blade, and a jacket having a water temperature of 20 ° C. was attached. Water is passed through at a rate of 20 liters / min., And the rotary shaft is cooled with water, and is loaded into a workpiece to prevent entry of the object to be treated with seal air). A 1: 1 (mass ratio) mixed powder of RX200 (average particle size 12 nm) manufactured by Nippon Aerosil Co., Ltd. and silica fine particles {RX50 manufactured by Nippon Aerosil Co. Ltd. (average particle size 40 nm) is 1.5% by mass with respect to the toner base particles. They were added in proportions and externally added under the following conditions. The temperature (thermocouple) of the workpiece was 25.0 ° C.

The shapes of the spherical mixing tank and the workpiece flow regulating plate are the same as those in the first embodiment. This spherical mixing treatment tank was mixed with a seal air amount of 1.0 Nm ³ / h, a turbine blade peripheral speed of 47 m / s, and a mixing time of 3 minutes. The maximum temperature at the first stage was 27.9 ° C.

  After completion of the first stage of the mixing process, the process waited for 5 minutes, and at the stage where the thermocouple showed 25.9 ° C., as the second stage of external addition process, titanium oxide fine particles {manufactured by Titanium Industry Co., Ltd. Particle diameter 30 nm)} was added at a ratio of 0.5 mass% with respect to the toner base particles, the peripheral speed of the turbine blade was 47 m / s, the mixing time was 3 minutes, and the mixing treatment was performed in the same manner as in the first stage. . The maximum temperature at the second stage was 28.8 ° C.

  After completion of the second stage mixing process, the process waited for 5 minutes, and at the stage where the thermocouple showed 26.0 ° C., as the third stage external addition process, zinc stearate particles {manufactured by NOF Corporation, MZ2 (average particle size 0.9 μm)} is added at a ratio of 0.1% by mass with respect to the toner base particles, the peripheral speed of the turbine blade is 47 m / s, the mixing time is 3 minutes, and the first stage. Mixing treatment was performed in the same manner. The maximum temperature at the third stage was 29.7 ° C.

  The ratio (yield) of the recovered weight to the input weight of the object to be processed was 97.1%. In the obtained toner, the number release rate of silica fine particles was 0.9% by number, the number release rate of titania fine particles was 3.9% by number, and the amount of free toner base particles was 26.8% by number.

  Further, when the charge amount distribution of the toner on the developing roller was measured in the same manner as in Example 1, the positively charged toner amount was 7.0% by number, and the ratio between the charge amount and the mass determined from the particle diameter ( The standard deviation (μC / g) of Q / m was 8.7.

A uniform external addition process with a high recovery rate, a small amount of free external additive and a positively charged toner, and a narrow charge amount distribution could be performed in a short time.
(Comparative Example 1)
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.

  3.2 kg of the obtained toner base particles were added to a spherical mixing tank (Mitsui Mining Co., Ltd., Q type 20L, a stirring blade is a turbine blade, and a jacket having a water temperature of 20 ° C. was attached. Water is passed through at a rate of 20 liters / min., And the rotary shaft is cooled with water, and is loaded into a workpiece to prevent entry of the object to be treated with seal air). A 1: 1 (mass ratio) mixed powder of RX200 (average particle size 12 nm) manufactured by Nippon Aerosil Co., Ltd. and silica fine particles {RX50 manufactured by Nippon Aerosil Co. Ltd. (average particle size 40 nm) is 1.5% by mass with respect to the toner base particles. They were added in proportions and externally added under the following conditions. The temperature (thermocouple) of the workpiece was 25.0 ° C.

The shapes of the spherical mixing tank and the workpiece flow regulating plate are the same as those in the first embodiment. This spherical mixing treatment tank was mixed with a seal air amount of 1.0 Nm ³ / h, a turbine blade peripheral speed of 55 m / s, and a mixing time of 3 minutes. The maximum temperature at the first stage was 28.9 ° C.

  About 10 minutes after the completion of the first stage mixing process, at the stage where the thermocouple showed 25.0 ° C., as the second stage external addition process, titanium oxide fine particles {manufactured by Titanium Industry Co., Ltd., STT30S (average Particle diameter 30 nm)} was added at a ratio of 0.5 mass% with respect to the toner base particles, the peripheral speed of the turbine blade was 55 m / s, the mixing time was 3 minutes, and the mixing treatment was performed in the same manner as in the first stage. . The maximum temperature at the second stage was 28.2 ° C.

  About 10 minutes after the completion of the second stage mixing process, at the stage where the thermocouple showed 25.0 ° C., as the third stage external addition process, zinc stearate particles {manufactured by NOF Corporation, MZ2 (average particle size 0.9 μm)} is added at a rate of 0.1% by mass with respect to the toner base particles, the peripheral speed of the turbine blade is 55 m / s, and the mixing time is 3 minutes. Mixing treatment was performed in the same manner. The maximum temperature at the third stage was 28.7 ° C.

  FIG. 5B shows an explanatory diagram of the temperature change of the object to be processed in the vicinity of the inner wall of the tank during the mixing process in the first stage, the second stage, and the third stage, and the waiting time.

  The ratio (yield) of the recovered weight to the input weight of the object to be processed was 96.9%. In the obtained toner, the number release rate of silica fine particles was 2.5% by number, the number release rate of titania fine particles was 6.7% by number, and the amount of free toner base particles was 32.8% by number.

  Further, when the charge amount distribution of the toner on the developing roller was measured in the same manner as in Example 1, the positively charged toner amount was 11.5% by number, and the ratio between the charge amount and the mass determined from the particle diameter ( The standard deviation (Q / m) of Q / m was 15.9.

  The amount of free external additive and positively charged toner was large, the charge amount distribution was wide, and uniform external addition processing could not be performed.

FIG. 1 is a central sectional view of a spherical mixing treatment tank. FIG. 2 is a plan view of an example of a stirring blade. FIG. 3 is a view showing a state where the upper hemisphere portion of the mixed treatment layer is opened from the flange portion and viewed from the inside. FIG. 4 is a central sectional view of the Henschel type mixing treatment tank. FIG. 5 is a diagram for explaining the temperature change of the workpiece in the vicinity of the inner wall of the tank during the mixing process in each stage of Example 1 (a) and Comparative Example 1 (b) and the standby time.

Explanation of symbols

1 is a spherical mixing treatment tank, 2 is a horizontal disk-shaped tank bottom, 3 is a rotary drive shaft, 4 is a donut-shaped disk, 5 is a stirring blade, 6 is an air seal hole, 7 is a cylindrical member, 8 is a flange, 9 is a jacket, 11 is an agitating blade, 12 is a flow regulating plate for processing object, 13 is a mounting member, and 14 is a thermocouple.

Claims (3)

In the method for producing a toner in which external additive particles are divided into a plurality of stages and externally added using a spherical mixing treatment tank having a water-cooled jacket on spherical resin particles containing at least a colorant, the spherical mixing treatment tank However, a horizontal disk-shaped tank bottom, and a stirring blade that discharges the processing object spirally upward along the inner wall of the processing tank is attached to a rotary drive shaft that vertically penetrates the center of the horizontal disk-shaped tank bottom, In addition, a cylindrical member that vertically penetrates the top of the mixing treatment layer on the extension line of the rotation drive shaft is disposed so that the tip thereof is located in the mixing treatment tank, and is released spirally upward by the rotation of the stirring blade. In addition to having a structure in which the processed material is moved to the top of the tank to reduce its kinetic energy, and the processed material is re-supplied to the stirring blades at the bottom of the tank, the second and subsequent external addition processes in the multi-stage external addition process After the first external addition process, When the temperature of the object to be processed near the tank wall cooled by the ket is higher than the temperature of the object to be processed near the tank wall before the first external addition treatment, the external additive particles in the second and subsequent stages are added. A method for producing toner, comprising starting external addition processing in the second and subsequent stages. The spherical resin particles have a shape factor (ML2 / A) of 1.05-1.40, a shape factor (PM2 / A) of 1.05-1.30, and a flow softening point (Tf1 / 2). The toner production method according to claim 1, wherein the temperature is 100 to 130 ° C. The external additive particles are selected from at least hydrophobized silica fine particles, titanium oxide fine particles, particles composed of long-chain fatty acids or salts thereof, and finally particles composed of long-chain fatty acids or salts thereof are externally added in the multistage external treatment. The toner production method according to claim 1, wherein the toner is subjected to an additive treatment.

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