JP4238691B2 - Toner for electrophotography and image forming apparatus using the toner - Google Patents

Description

  The present invention relates to a toner used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, etc., and forming an image by thermal fixing, a method for producing the toner, and image formation using the toner Relates to the device.

  Generally, toner for electrostatic image formation uses toner fine particles made of a binder resin containing a coloring component such as a pigment or dye and, if necessary, a charge control agent, as a toner mother particle, and the outside (surface) of the toner mother particle. In addition, for the purpose of imparting fluidity or controlling chargeability, it is manufactured by a method of adding an external additive. As the external additive, positively chargeable silica fine particles, negatively chargeable silica fine particles, inorganic fine particles other than silica (such as titanium oxide fine particles), metal soap (fatty acid metal salt) and the like are used.

  Among these, metal soaps are attracting attention for their binding properties, and are often used as external additives in toners as disclosed in, for example, Patent Documents 1 to 7. Patent Document 1 discloses a hydrophobic silica fine particle or hydrophobic titania as a first component, a hydrophobic silica fine particle or hydrophobic titania having a particle size larger than the first component as a second component, an inorganic fine particle as a third component, and a fatty acid metal. A method is disclosed in which salt is used as the fourth component, and these first to fourth components are externally added to the toner base particles at the same time, or the first component is finally added externally. In Patent Document 1, a fatty acid metal salt is added from the viewpoint of preventing sticking of the surface of the photoreceptor and prevention of black spot generation, and thereafter, hydrophobic silica or hydrophobic titania is added. However, hydrophobic silica or hydrophobic titania, which is an external additive, is easily released from the toner surface, and the charging stability over a long period of time cannot be maintained and the fluidity of the toner is reduced. There is a problem that a decrease, a decrease in image density, and the like occur.

In Patent Document 2, silica having an amino group on the surface and a fatty acid metal salt are simultaneously added to obtain a toner by one external addition treatment. In the toner obtained by this method, the liberation rate of hydrophobic silica is slightly improved, but there remains a problem that the charge amount of the toner cannot be stably maintained. Patent Documents 3 to 7 also describe that a fatty acid metal salt is externally added when preparing a toner. In these Patent Documents 3 to 7, as in Patent Document 2, the fatty acid metal salt is added simultaneously with other external additives, and the toner is obtained by one external addition process. The toners described in Patent Documents 3 to 7 still have a problem that the charge amount of the toner cannot be stably maintained.
JP 2001-100452 A Japanese Patent No. 2502353 Japanese Patent Publication No. 8-33681 Japanese Patent No. 2759510 Japanese Patent Laid-Open No. 9-114129 JP-A-11-323396 JP 2001-296688 A JP 2002-202622 A

  An object of the present invention is to provide a toner that is excellent in charge uniformity, maintains charge stability for a long period of time even in repeated use, has high fluidity and transfer efficiency, and does not decrease image density.

The present invention relates to a toner obtained by adding two or more external additives to toner base particles containing a binder resin and a colorant, wherein the external additives are added by multi-stage treatment, and in the final stage of the multi-stage treatment. The present invention provides a toner in which an external additive containing a metal salt of a long-chain fatty acid is added with a higher share than in other stages.

In a preferred embodiment, the external additive is added using a mixer having rotor blades, and the external additive containing a metal salt of a long-chain fatty acid is controlled in the final stage by controlling the rotational speed of the rotor blades. The agent is added with a higher share than the other stages.

In another preferred embodiment, the external additive is added using a mixer having rotor blades, and a long-chain fatty acid is used in the final stage by controlling the distance between the rotor blades and the mixer wall. The external additive containing the metal salt is added with a higher share than the other stages.

In a preferred embodiment, negatively-chargeable silica fine particles, at least one of the external additive is selected from the group consisting of titanium oxide fine particles and positively chargeable silica fine particles are added to the toner mother particles, at the final stage of a long chain fatty acid External additives including metal salts are added with a higher share than other stages.

In another preferred embodiment, in the multi-stage treatment, negatively chargeable silica fine particles are first added to the toner base particles, and the external additive containing a metal salt of a long-chain fatty acid in the final stage has a higher share than the other stages. Added at.

In yet another preferred embodiment, in the multi-stage process, is first negatively chargeable silica fine particles added, followed by titanium oxide fine particles are added, at the final stage of a long chain fatty acid metal
An external additive containing salt is added with a higher share than the other stages.

In another preferred embodiment, in the multi-stage treatment, titanium oxide fine particles are added first, and an external additive containing a metal salt of a long-chain fatty acid is added at a higher share than other stages in the final stage. .

In still another preferred embodiment, in the multi-stage treatment, negatively-charged silica fine particles and titanium oxide fine particles are first added, and an external additive containing a metal salt of a long-chain fatty acid is added to the final step more than the other steps. Added with a high share.

In another preferred embodiment, in the multi-stage treatment, at least one external additive selected from the group consisting of negatively chargeable silica fine particles and titanium oxide fine particles is added,
Next, positively chargeable silica fine particles are added, and in the final stage, a metal salt of a long chain fatty acid is added with a higher share than in the other stages.

In still another preferred embodiment, in the multi-stage treatment, at least one external additive selected from the group consisting of negatively chargeable silica fine particles and titanium oxide fine particles is first added, and positively chargeable silica fine particles are added in the final stage. And metal salts of long chain fatty acids are added with a higher share than the other stages.

The present invention also provides a toner manufacturing method including a step of externally adding two or more external additives to toner base particles containing a binder resin and a colorant in a multistage process, and in the final stage of the multistage process ,
Provided is a method including a step of adding an external additive containing a metal salt of a long-chain fatty acid with a higher share than other steps.

In a preferred embodiment, the external additive is added using a mixer having rotor blades, and the metal salt of a long-chain fatty acid is used in the final stage by controlling the rotational speed of the rotor blades. > It includes a process of adding an external additive containing at a higher share than other stages.

In another preferred embodiment, the addition of the external additive is performed using a mixer having rotor blades, and by controlling the distance between the rotor blades and the mixer wall, a long chain is added in the final stage. It includes a step of adding an external additive containing a metal salt of a fatty acid with a higher share than other stages.

In a preferred embodiment, a step of adding at least one external additive selected from the group consisting of negatively chargeable silica fine particles, titanium oxide fine particles and positively chargeable silica fine particles to the toner base particles, and a long chain in the final stage A step of adding an external additive containing a metal salt of a fatty acid with a higher share than in other stages.

In another preferred embodiment, the negatively chargeable silica fine particles are first added to the toner base particles, and an external additive containing a metal salt of a long-chain fatty acid is added at a higher share than the other stages in the final stage. The process of carrying out.

In still another preferred embodiment, the step of first adding the negatively chargeable silica fine particles to the toner base particles, the step of adding titanium oxide fine particles, and the external additive comprising a metal salt of a long-chain fatty acid at the final stage Is added at a higher share than other stages.

In another preferred embodiment, the method includes a step of adding the titanium oxide fine particles first, and a step of adding an external additive containing a metal salt of a long-chain fatty acid at a final stage in a higher share than the other stages.

In still another preferred embodiment, the negatively chargeable silica fine particles and titanium oxide fine particles are added first, and in the final stage, an external additive containing a metal salt of a long-chain fatty acid has a higher share than the other stages. Adding.

In another preferred embodiment, the step of adding at least one external additive selected from the group consisting of the negatively chargeable silica fine particles and the titanium oxide fine particles, then the step of adding positively chargeable silica fine particles, and In the final stage, a process of adding a metal salt of a long-chain fatty acid with a higher share than the other stages is included.

In still another preferred embodiment, the step of adding at least one external additive selected from the group consisting of the negatively chargeable silica fine particles and the titanium oxide fine particles, and then the positively chargeable silica fine particles and the long chain fatty acid metal Including adding salt in a higher share than other stages.

  The present invention further provides an image forming apparatus comprising any one of the above toners.

  In a preferred embodiment, the image forming apparatus includes a latent image carrier on which an electrostatic latent image is formed; and transports toner to the latent image carrier to develop the electrostatic latent image on the latent image carrier. A toner carrying member; and a developer having a toner regulating member that regulates the amount of toner conveyed to the latent image carrying member by the toner carrying member.

The toner of the present invention is obtained by performing a multistage treatment when adding an external additive to the toner base particles, and adding a metal salt of a long-chain fatty acid at a higher share than other stages in the final stage of the multistage treatment. Finally, by adding a metal salt of a long chain fatty acid with a high share, it acts as a binder for external additives such as negatively chargeable silica fine particles, titanium oxide fine particles, and positively chargeable silica fine particles,
Release of these external additives from the toner surface can be suppressed. In addition, by adding a metal salt of a long-chain fatty acid with a high share at the end, the effect as a toner lubricant is further exhibited, preventing toner aggregation, and external additives are added to the toner base particles by friction between toners. It can be prevented from being buried inside, and the uniformity of charging can be maintained. Furthermore, the charging stability can be maintained even after repeated use. Further, in the developing device, due to the contact between the toner and the photoconductor, the metal salt of the long chain fatty acid migrates from the toner surface to the photoconductor surface, lubricates the photoconductor surface, and the surface of the photoconductor surface by the external additive on the toner surface. Polishing can be prevented.

  In the present specification, an external additive or an external additive is a material that is externally added to toner base particles such as particles of long chain fatty acid or a salt thereof, negatively charged silica particles, titanium oxide particles, and positively charged silica particles. The addition of these external additives (external additives) to the outside (surface) of the toner base particles is called external addition.

  First, (i) toner base particles and materials constituting the toner base particles (binder resin and colorant, release agent, dispersant, charge control agent, magnetic agent, etc.), which are materials used in the present invention. Internal additives), (ii) long chain fatty acids or salts thereof, (iii) negatively chargeable silica fine particles, (iv) titanium oxide fine particles, (v) positively chargeable silica fine particles, and added as needed (vi ) Inorganic fine particles will be described, and then the toner of the present invention will be described.

(I) Materials used in the present invention (i) Toner base particles The toner base particles include a binder resin and a colorant, and include a release agent, a dispersant, a charge control agent, a magnetic agent, etc. as necessary. Contains additives. The toner base particles are positively or negatively charged, and preferably negatively charged. There are several methods for charging the toner base particles so as to have a negative charge amount in an appropriate range. For example, a negative charge control agent is blended with a positively chargeable binder resin, and if the chargeability of the negatively chargeable resin is insufficient, a negative charge control agent is further blended, or the binder resin itself is negatively charged. For example, there is a method of making a functional resin. Hereinafter, the material constituting the toner base particles and the method for producing the toner base particles will be sequentially described.

(i-1) Material composing toner mother particles (binder resin)
As the binder resin, a resin generally used as a toner is used. Examples of such binder resins include polystyrene resins, acrylate resins or methacrylate resins (hereinafter referred to as (meth) acrylate resins), styrene-acrylic resins, polyester resins, polyethylene resins, epoxy resins, Silicone resin, polypropylene resin, fluororesin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polyvinyl butyral resin, and a copolymer containing components of these resins are used.

  Of these, polystyrene resins and styrene- (meth) acrylate resin copolymers are preferably used.

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

  Examples of the styrene- (meth) acrylate resin copolymer include acrylate-styrene-acrylonitrile copolymer (ASA resin), styrene-diethylamino-ethyl methacrylate copolymer, styrene-methyl methacrylate copolymer, styrene. -N-butyl methacrylate copolymer, styrene-methyl methacrylate-n-butyl acrylate copolymer, styrene-methyl methacrylate-butyl allylate-N- (ethoxymethyl) acrylamide copolymer, styrene-glycidyl methacrylate copolymer Polymer, styrene-butadiene-dimethylaminoethyl methacrylate copolymer, styrene-acrylic acid ester-maleic acid ester copolymer, styrene-methyl methacrylate-acrylic acid 2-ethylhexyl Copolymer, styrene-n-butylarylate-ethyl glycol methacrylate copolymer, styrene-n-butyl methacrylate-acrylic acid copolymer, styrene-n-butyl methacrylate-maleic anhydride copolymer, styrene- Examples thereof include butyl acrylate-isobutyl maleic acid half ester-divinylbenzene copolymer, styrene-butadiene-acrylate copolymer, and styrene-acrylate copolymer.

  The mass average molecular weight of the binder resin used in the present invention is not particularly limited, but is usually preferably 2,000 to 30,000, more preferably 4,000 to 25,000, and 6,000 to 20,000. More preferably, it is 000. When the molecular weight is less than 2,000, the viscosity at the time of kneading is lowered, and there is a possibility that the colorant cannot be sufficiently dispersed. Therefore, the saturation or transparency of the obtained toner may be reduced. When the molecular weight is larger than 30,000, the viscosity becomes too high, and the colorant cannot be sufficiently dispersed, and the saturation or transparency of the toner may be lowered. The binder resin may be a mixture of a plurality of resins having a molecular weight within the above range.

  The molecular weight of the binder resin is measured by gel permeation chromatography (GPC).

  When fixing the toner in image formation by the thermal fixing method, the flow softening point (Tm) of the binder resin is preferably low. For example, Tm is preferably 85 to 140 ° C, more preferably 90 to 120 ° C, and further preferably 100 to 110 ° C. The glass transition temperature (Tg) of the binder resin is preferably 40 to 90 ° C, more preferably 50 to 80 ° C. In addition, the flow softening point (Tm) was measured under the following conditions using “Flow Tester CFT-500D” manufactured by Shimadzu Corporation as a sample by pressure-molding 1.0 g of a binder resin into a pellet. 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.

  When the toner is fixed by the pressure fixing method, a wax-like resin is preferably used as the binder resin. Examples of the wax-like resin include polyethylene resins, polyethylene-vinyl acetate copolymers, and natural waxes among the above binder resins.

  The binder resin is produced by a polymerization method such as emulsion polymerization, dispersion polymerization, suspension polymerization, or a pulverization method including kneading, pulverization, and classification steps. Considering the uniformity or fluidity of the finally obtained toner particles, the binder resin is preferably a resin obtained by a polymerization method.

  Moreover, the said binder resin may be used independently and may blend and use 2 or more types. Needless to say, the binder resin is an example, and is not limited thereto.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

(Release agent)
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, Ceridust 3715 (manufactured by Hoechst), Mitsui High Wax 420M Koe Industries Co., Ltd.), Sun Wax E-300, Sun Wax E-250P (Sanyo Kasei Kogyo Co., Ltd.) and other oxidized polyethylene waxes, Hoechi Non-oxidized polypropylene wax such as st Wachs PP230 (Hoechst), Viscol 330-P, Biscol 550-P, Biscol 660P (Sanyo Chemical Industries), and Biscol TS-200 (Sanyo Chemical Industries, Ltd.) Oxidized polypropylene wax, such as

  As the long chain 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.

(Dispersant)
As the dispersant, metal soap, polyethylene glycol, or the like is used.

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

  Examples of the negative charge control agent include metal salts or metal complexes of salicylic acid derivatives, metal salts of benzylic acid derivatives, and phenylborate quaternary ammonium salts. As the metal salts of salicylic acid derivatives or benzylic acid derivatives, these zinc salts, nickel salts, copper salts, chromium salts and the like are preferably used.

  Examples of commercially available negative charge control agents include oil black (Color Index 26150), oil black BY (manufactured by Orient Chemical Co., Ltd.), Bontron S-22 (manufactured by Orient Chemical Co., Ltd.), and salicylic acid metal complex E. -81 (produced by Orient Chemical Co., Ltd.), thioindigo pigment, sulfonylamine derivative of copper phthalocyanine, Spiron Black TRH (produced by Hodogaya Chemical Co., Ltd.), Bontron S-34 (produced by Orient Chemical Co., Ltd.) ), Nigrosine SO (manufactured by Orient Chemical Industry Co., Ltd.), Ceres Schwartz (R) G (manufactured by Farben Fabricen Bayer), Chromogen Schwarz ETOO (CINO.14645), Azo Oil Black (R) (National Aniline). Among these, salicylic acid metal complex E-81 is preferably used. These negative charge control agents can be used alone or in combination.

  The negative charge control agent is preferably blended in the binder resin so that the charge amount of the toner base particles is −5 to −60 μC / g. Therefore, although the addition amount with respect to binder resin is determined by the 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 Examples include Schwartz BB (Solvent Black 3: Color Index 26150), Fett Schwartz HBN (CI NO. 26150), Brilliant Spirits Schwarz TN (manufactured by Farben Fabricken Bayer), and Zabon 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.

(Magnetic agent)
Examples of the magnetic agent include metal powders such as Fe, Co, Ni, Cr, Mn, and Zn, metal oxides such as Fe ₃ O ₄ , Fe ₂ O ₃ , Cr ₂ O ₃ , and ferrite, and manganese and acid. Examples include alloys that exhibit ferromagnetism by heat treatment of the alloys. These may be pretreated with a coupling agent or the like.

(i-2) Manufacture of toner base particles Toner base particles are added to the binder resin with the colorant and, if necessary, internal additives such as a release agent, a dispersant, a charge control agent, and a magnetic agent. And manufactured. For example, a method for producing toner base particles by a pulverization method including a kneading, pulverization, and classification process will be described. First, a predetermined amount of additives such as a binder resin, a colorant, and a release agent are charged into a mixer such as a Henschel mixer 20B (Mitsui Mining Co., Ltd.) and mixed uniformly. The mixing ratio of additives such as a binder resin, a colorant, a charge control agent, and a release agent is appropriately determined in consideration of the color of the toner, chargeability, and the like.

  Next, the above mixture is put 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. The obtained melt-kneaded product is finely pulverized using a pulverizing means to obtain toner mother particles having a desired average particle size. The pulverization may be performed by, for example, a mechanical pulverizer turbo mill (Kawasaki Heavy Industries, Ltd.) in addition to collision pulverization using jet air using a jet pulverizer 200AFG (Hosokawa Micron Corporation) or IDS-2 (Nippon Pneumatic Industrial Co., Ltd.). )), Super Rotor (Nisshin Engineering Co., Ltd.), etc.

  Next, the particle size of the obtained toner base particles is adjusted using, for example, wind power or rotor rotation. For example, when the air classifier 100ATP (Hosokawa Micron Co., Ltd.), DSX-2 (Nippon Pneumatic Industrial Co., Ltd.), Elbow Jet (Nittetsu Mining Co., Ltd.) or the like is used, a sharp particle size distribution is obtained.

  The toner base particles are also a method in which an internal additive such as a resin and a colorant constituting the toner base particles is dissolved in an organic solvent, dispersed and granulated with a classifier and an emulsifier in an aqueous solvent, and separated and dried. You may produce by.

  The charge amount of the toner base particles is preferably −5 to −60 μC / g. When the charge amount is smaller than this range, toner leakage from the developing device becomes severe, and when it is larger than −60 μC / g, it is necessary to apply an excessive development bias in order to obtain a sufficient image density. Problem arises.

The charge amount of the toner base particles is measured as follows, for example. In an environment of 25 ° C. and 45% RH, 0.03 g of toner base particles and 0.97 g of ferrite carrier are mixed in a 20 ml polyethylene container and stirred at 100 rpm for 15 minutes to charge the toner base particles. Thereafter, 0.3 g of this mixture is sampled, and nitrogen gas having a pressure of 0.3 kg / cm ² is blown onto the mixture of the toner base particles and the carrier to separate the toner base particles and the ferrite carrier. Next, the charge amount (Q / m) for each toner is measured to measure the charge amount of the toner base particles. For the measurement of the charge amount, for example, an E-SPART analyzer manufactured by Hosokawa Micron Corporation is used.

(Ii) long chain fatty acids or salts thereof,
There is no restriction | limiting in particular in the long chain fatty acid used for this invention, or its salt. As the long chain fatty acid, a long chain 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. Examples of long chain fatty acids include long chain saturated fatty acids and long chain unsaturated fatty acids. Long chain saturated fatty acids are preferably 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 particles are preferably used. The particles comprising a long-chain saturated fatty acid or a salt thereof may be used alone or in combination of two or more.

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

  The long-chain fatty acid or salt thereof, particularly metal soap, preferably has a melting point of about 100 to 150 ° 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 150 ° C, the lubricating action may be reduced.

  As metal soaps, metal soaps manufactured by the direct method and metal soaps manufactured by the double decomposition method are known. It is preferable to adjust the particle size so that

  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% 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% by mass, the fluidity is inferior, the charge rising property is remarkably deteriorated, and noise such as fog may be generated.

(Iii) Negatively chargeable silica fine particles The negatively chargeable silica fine particles used in the present invention are not particularly limited. As the negatively chargeable silica fine particles, generally, negatively chargeable silica fine particles having an average particle diameter of 4 to 120 nm, preferably 5 to 50 nm, and more preferably 6 to 40 nm are used. The smaller the average particle size of the negatively chargeable silica fine particles, the higher the fluidity of the obtained toner. If it is smaller than 4 nm, the toner may be buried in the toner base particles. If it exceeds 120 nm, the fluidity may be extremely deteriorated. In this specification, the average particle diameter of fine particles such as negatively chargeable silica, toner base particles, and toner particles means a volume average particle diameter unless otherwise specified.

  In the present invention, negatively chargeable silica fine particles having a uniform particle diameter may be used alone, or two or more negatively chargeable silica fine particles having different average particle diameters may be used in combination. In general, negatively chargeable silica fine particles having a small average particle diameter (silica having a small particle diameter) are used alone. However, by using a small particle size silica and a negatively charged silica fine particle having a large average particle size (a large particle size silica) in combination, the absolute value of the charge amount is smaller than when only a small particle size silica is used. In addition, the large particle size silica becomes resistance, and the small particle size silica can be prevented from being embedded in the toner base particles, so that long-term charging stability is excellent. 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.

  When the negatively chargeable silica fine particles are used alone, in general, negatively chargeable silica fine particles having a small average particle diameter are preferably used. The average particle diameter of the negatively chargeable silica fine particles is preferably 5 to 20 nm, and more preferably 6 to 15 nm.

  When two or more negatively chargeable silica fine particles having different average particle diameters are used in combination, the average particle diameter is 5 to 20 nm, preferably 6 to 15 nm, and the average particle diameter is 20 to 50 nm. It is preferable to use silica having a large particle diameter of 20 to 40 nm. 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 the large particle size silica to the 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 mass ratio. 1 is preferable. Within this range, fluidity is imparted to the toner, and long-term charging stability can be obtained.

  In the case of using large particle size silica and small particle size silica, these may be mixed and added at the same time during the production described below, 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 dimethylsilicone, methylphenylsilicone, 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.

  As the hydrophobic negatively chargeable silica fine particles, commercially available RX200 and RX50 manufactured by Nippon Aerosil Co., Ltd., TG811F, TG810G and TG308F manufactured by Cabot Corp. are used.

(Iv) Titanium oxide fine particles In the present invention, titanium oxide (titania) fine particles are used as needed for the purpose of adjusting the charge of the toner. Like the positively chargeable silica fine particles, the titanium oxide fine particles can be added after the addition of the negatively chargeable silica fine particles and before the addition of the particles of the long chain fatty acid or a salt thereof. It is preferable in terms of binding to the mother particles and exhibiting the effect of a long chain fatty acid or a salt thereof as a binder and the effect of a lubricant.

  There is no restriction | limiting in particular in the titanium oxide fine particle used by this invention. Fine particles of titanium oxide having a relatively low electrical resistivity are preferably used. 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 microparticle, It is preferable that a particle size or the magnitude | size of a major axis is a magnitude | size of 10-30 nm. In the case of rutile-anatase type titanium oxide, titanium oxide fine particles having a major axis of about 10 to 30 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. The addition of the titanium oxide fine particles and the positively chargeable silica fine particles in a mass ratio of 1: 3 to 3: 1 can adjust the charge without causing an extreme decrease in the electric resistance of the toner. In terms, it is preferable.

  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. It 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.

  As the hydrophobic titanium oxide fine particles, STT-30S manufactured by Titanium Industry Co., Ltd. is used.

(V) Positively Charged Silica Fine Particles In the present invention, the positively chargeable silica fine particles are used as necessary for adjusting the charge of the toner. The positively chargeable silica fine particles are added after the addition of the negatively chargeable silica fine particles and before the addition of the long chain fatty acid or the salt thereof, so that the negatively chargeable silica fine particles are firmly bonded to the toner base particles. And long-chain fatty acids or salts thereof are preferable for exhibiting the effect as a binder and the effect as a lubricant.

  The positively chargeable silica fine particles used in the present invention are not particularly limited. The volume average particle diameter of the positively chargeable silica fine particles is preferably 10 to 50 nm, more preferably 15 to 40 nm in consideration of fluidity and the like.

  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.

  As the hydrophobic positively chargeable silica fine particles, commercially available NA50H manufactured by Nippon Aerosil Co., Ltd., TG820F manufactured by Cabot Co., Ltd., etc. are used.

  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, if necessary.

(Vi) Inorganic fine particles 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. The inorganic fine particles other than the titanium oxide fine particles can also be added after the addition of the negatively chargeable silica fine particles and before the addition of the particles of the long chain fatty acid or a salt thereof. It is preferable for binding and exhibiting the effect of a long-chain fatty acid or a salt thereof as a binder and the effect of a lubricant.

For example, as inorganic fine particles, fine particles of metal oxides such as aluminum oxide, strontium oxide, tin oxide, zirconia oxide, magnesium oxide and indium oxide; fine particles of nitride such as silicon nitride; fine particles of carbide such as silicon carbide; calcium sulfate And 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 low electrical resistivity are preferably used.

  Although there is no restriction | limiting in particular in the magnitude | size of the inorganic fine particle to add, It is preferable that a particle size is a magnitude | size of 10-30 nm. These inorganic fine particles are preferably subjected to a hydrophobic treatment on the surface for the purpose of stabilizing charging characteristics. For the hydrophobization treatment, the same method as any of the above-described hydrophobic methods for the negatively chargeable silica fine particles and the positively chargeable silica fine particles is employed.

(II) Toner of the Present Invention and Method for Producing the Same As described above, the toner of the present invention is obtained by adding an external additive by multistage treatment, and in the final stage, a long chain fatty acid or a salt thereof has a higher share than other stages. It is obtained by adding. The external additive (for example, negatively-charged silica fine particles, titanium oxide fine particles, positively-charged silica fine particles, particles composed of a long chain fatty acid or a salt thereof) is added to the toner base particles such as a Henschel mixer, Perpenmeier, etc. It is carried out using a machine or a method commonly used by those skilled in the art, such as a high-speed fluid mixer and a mixer using a mechanochemical method. The stirring speed and time in each step of the multi-stage treatment can be set independently, but the external addition of the particles consisting of the long-chain fatty acid or its salt, which is the last stage, is performed with a higher share than the other stages. .

  The method of increasing the share (for example, mixing share) at the time of external addition of particles comprising a long-chain fatty acid or a salt thereof may be determined depending on the apparatus for externally adding the external additive to the toner base particles. Among the above devices, when using a high-speed fluid mixer such as a Henschel mixer having a rotating blade, or Palpenmeier, (1) By increasing the rotating speed of the rotating blade, (2) the distance between the rotating blade and the mixer wall By the method of reducing (gap), the share at the time of mixing the particle | grains which consist of long chain fatty acid or its salt can be raised. When externally adding particles comprising a long-chain fatty acid or a salt thereof, 1.02 times or more, preferably 1.2 times or more, more preferably 1.5 times that of other fine particle external additives. It is preferable to apply the above high share. If a too high share is applied, other fine particles will be affected, so 3 times or less is preferable.

  Specifically, the toner of the present invention includes, for example, at least one external additive selected from the group consisting of negatively-charged silica fine particles, titanium oxide fine particles, and positively-charged silica fine particles added to the toner base particles. It is obtained by adding an external additive containing particles composed of a long-chain fatty acid or a salt thereof at a higher stage than in the other stages. Here, the “external additive containing particles comprising a long-chain fatty acid or a salt thereof” is used in the case of only particles comprising a long-chain fatty acid or a salt thereof, and multistage treatment with particles comprising a long-chain fatty acid or a salt thereof. It may be a combination with an external additive that has not been made.

  Hereinafter, other processes for obtaining the toner of the present invention will be described with various combinations exemplified. In addition, when the toner base particles are positively to weakly negatively charged during multi-stage processing, first add negatively charged silica fine particles (II-1), and first add negatively charged silica fine particles and titanium oxide fine particles. (II-2) or first adding titanium oxide fine particles (II-3) is performed. When the toner base particles are strongly negatively charged, first, positively charged silica fine particles are added (II-4), and first, positively charged silica fine particles and other external additives are added (II-5). ) Is performed. Hereinafter, these cases will be described.

(II-1) Toner obtained by first adding negatively chargeable silica fine particles 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 positively charged. The negatively chargeable silica fine particles are strongly adhered to the toner base particles because the work function of the negatively chargeable silica fine particles and the work function of the toner base particles are large. Can do. 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.

  As the negatively chargeable silica fine particles, it is preferable to use a small particle size silica and a large particle size silica in combination. By using negatively chargeable silica fine particles having different average particle diameters, the absolute value of the charge amount can be increased as compared with the case of using only negatively chargeable silica fine particles having a small particle diameter, and negative particles having a large particle diameter. The chargeable silica fine particles serve as resistance, and silica having a small particle diameter can be prevented from being embedded in the toner base particles, and the long-term charge stability is excellent. 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.

  When using a small particle size silica and a large particle size silica in combination, these silicas may be added at the same time, first adding a small particle size silica, then adding a large particle size silica. Good.

  The toner of the present invention can be obtained by first adding the negatively chargeable silica fine particles, and finally adding particles composed of a long-chain fatty acid or a salt thereof at a higher share than other processing steps. In this case, first, a silica having a small particle size and a silica having a large particle size are simultaneously added to the toner base particles, and finally, particles comprising a long-chain fatty acid or a salt thereof are added at a higher share than other processing steps. Step treatment, or first externally add silica with a small particle size, then externally add silica with a large particle size, and finally add particles of long-chain fatty acids or their salts with a higher share than other processing steps. The three-stage process to add is mentioned.

  First, negatively chargeable silica fine particles may be added to toner base particles, and then titanium oxide fine particles and positively chargeable silica fine particles may be 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 fine particles first, and then add the positively chargeable silica fine particles. 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 function as a charge adjusting agent, and the decrease in the electrical resistivity of the toner is suppressed, and the charge is reduced. It is made uniform. Furthermore, positively-charged silica particles are present in an appropriate ratio in the toner, and the fluidity of the toner is improved, and the positively-charged silica fine particles that are free serve as a carrier, Chargeability becomes more uniform.

  Positively-charged silica fine particles are added to the toner base particles added in the order of negatively-charged silica fine particles-titanium oxide fine particles, and finally, particles consisting of long-chain fatty acids or their salts have a higher share than other processing stages. To the toner base particles added in the order of four-stage treatment to be added or negatively chargeable silica fine particles-titanium oxide fine particles, finally, positively chargeable silica fine particles and particles of a long chain fatty acid or a salt thereof are simultaneously added. There is a three-stage process of adding with a higher share than the process stage. Further, two-stage treatment may be performed by simultaneously adding titanium oxide fine particles, positively chargeable silica fine particles, and particles of a long chain fatty acid or a salt thereof to the toner base particles to which negatively charged silica fine particles are externally added. Among these, positively-charged silica fine particles and long-chain fatty acid or a salt thereof are added at a higher share than other treatment stages, and three-stage treatment is performed, depending on the positively-charged silica fine particles and titanium oxide fine particles. It is preferable in that the surface charge can be adjusted most efficiently without extremely reducing the electric resistance.

  For example, the following (a) to (a) to (a) to (a) to the negatively chargeable silica fine particles are added first, and finally the particles composed of a long-chain saturated fatty acid or a salt thereof are added with a higher share than other processing steps. h) multi-stage treatment is exemplified: (a) Negatively charged silica fine particles-particles made of long chain saturated fatty acids or salts thereof; (b) Negatively charged silica fine particles-titanium oxide fine particles-long chain saturated fatty acids or salts thereof. (C) Negatively-charged silica fine particles-positively-charged silica fine particles-particles composed of long-chain saturated fatty acids or salts thereof; (d) Negative-charged silica fine particles-titanium oxide fine particles-positively-charged silica fine particles-long Particles composed of chain saturated fatty acids or salts thereof; (e) Negatively charged silica particles— (positively charged silica particles + particles composed of long chain saturated fatty acids or salts thereof); (f) Negatively charged silica particles—titanium oxide particles -(Positively chargeable silica fine particles + (G) Negatively charged silica fine particles— (titanium oxide fine particles + long chain saturated fatty acids or particles thereof); (h) Negatively charged silica fine particles— (titanium oxide fine particles) + Positively-charged silica fine particles + long-chain saturated fatty acids or salts thereof);

  In addition, in the order of the steps, when adding the small particle size silica alone, the small particle size silica and the large particle size silica are added simultaneously, unless otherwise specified, to the addition of the negatively chargeable silica fine particles. And a case where two-stage treatment is performed in the order of small particle size silica-large particle size silica. For example, (a) particles of negatively charged silica fine particles-long chain saturated fatty acids or salts thereof include (a1) particles of silica-long chain saturated fatty acids or salts thereof having a small particle size; (a2) small particle sizes (A3) (small particle diameter silica + large particle diameter silica) —particles composed of long chain saturated fatty acid or salt thereof; included. In addition, (h) negatively charged silica fine particles- (titanium oxide fine particles + positively charged silica fine particles + long chain saturated fatty acids or particles thereof) include (h1) (small particle size silica + large particle size particles). Silica)-(titanium oxide fine particles + positively charged silica fine particles + long chain saturated fatty acid or a salt thereof).

(II-2) Toner obtained by first adding negatively chargeable silica fine particles and titanium oxide fine particles When negatively chargeable silica fine particles and titanium oxide fine particles are added simultaneously to the toner base particles, negatively chargeable silica From the relationship between the work function of the fine particles, the work function of the titanium oxide fine particles, and the work function of the toner base particles, the negatively chargeable silica fine particles are relatively strongly attached to the toner base particles, so that the release of the silica fine particles is suppressed. In addition, the effect by performing the multistage process which adds the long chain fatty acid or its salt with a higher share than another process stage at the end mentioned above is exhibited.

  Such multi-stage treatment includes: (i) (negatively charged silica fine particles + titanium oxide fine particles) —particles composed of long chain saturated fatty acids or salts thereof; (j) (negatively charged silica fine particles + titanium oxide fine particles) —positive Examples include: electrified silica fine particles-long chain saturated fatty acids or salts thereof; (k) (negatively charged silica fine particles + titanium oxide fine particles)-(positive chargeable silica fine particles + long chain saturated fatty acids or salts thereof); When negatively chargeable silica fine particles and titanium oxide fine particles are added simultaneously, (i) (negatively chargeable silica fine particles + titanium oxide fine particles) -long chain saturated fatty acid or a salt thereof includes (i1) ( (Small particle size silica + titanium oxide fine particle) -particles composed of long chain saturated fatty acid or salt thereof; (i2) (Small particle size silica + large particle size silica + titanium oxide fine particle) -long chain saturated fatty acid or salt thereof (I3) silica having a small particle diameter + (silica having a large particle diameter + titanium oxide fine particles) −particles composed of a long-chain saturated fatty acid or a salt thereof; and the like.

(II-3) Toner Obtained by First Adding Titanium Oxide Fine Particles When titanium oxide fine particles are added first, next, particles comprising a long chain fatty acid or a salt thereof may be added. Next to the titanium oxide fine particles, negatively chargeable silica fine particles may be added, and finally particles composed of long-chain fatty acids or salts thereof may be added. If necessary, the positively charged silica fine particles are added before the long-chain fatty acid or salt thereof or simultaneously with the long-chain fatty acid or salt thereof, thereby preventing the charge amount from decreasing sharply. Can be adjusted. In addition to this effect, the effect of the long-chain fatty acid or salt thereof is exhibited.

  Such multi-stage treatment includes (l) particles of titanium oxide fine particles-long chain saturated fatty acids or salts thereof; (m) particles of titanium oxide fine particles-negatively charged silica fine particles-long chain saturated fatty acids or salts thereof; (n) Titanium oxide fine particles-negatively chargeable silica fine particles-positively chargeable silica fine particles-particles composed of long chain saturated fatty acids or salts thereof; (o) Titanium oxide fine particles-negatively chargeable silica fine particles- (positively chargeable silica fine particles + For example, particles composed of a long-chain saturated fatty acid or a salt thereof). In particular, the processing steps (n) and (o) are effective even when the toner base particles are strongly negatively charged.

(II-4) Toner obtained by first adding positively charged silica fine particles When toner base particles are strongly negatively charged, first add positively charged silica fine particles; first positively charged silica fine particles And other external additives are added. Among them, 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 work function of the positively chargeable silica fine particles and the work function of the toner base particles are Therefore, 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 electric resistance value in advance, the surface charge when the low-electrical resistance titanium oxide fine particles are externally added is not greatly reduced (that is, positively charged). The chargeable silica fine particles function as a charge adjusting agent), and the decrease 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.

  Examples of such multi-stage treatment include (p) positively charged silica fine particles—long chain fatty acid or salt thereof; (q) positively charged silica fine particles— (titanium oxide fine particles + long chain fatty acid or salt thereof); The

  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. In (p), which is an example of multi-stage treatment, titanium oxide fine particles are not added, but if the charge amount is in an appropriate range, it may not be added.

(II-5) Toner obtained by first adding positively chargeable silica fine particles and other external additives When other external additives are negatively chargeable silica fine particles, the toner base particles are negatively charged. From the viewpoint of charge control, it is preferable to add negatively-charged silica fine particles simultaneously with positively-charged silica fine particles. As an example of multi-stage treatment in which positively charged silica fine particles and negatively chargeable silica are added first, (r) (positively charged silica fine particles + negatively charged silica fine particles) -titanium oxide fine particles-long chain fatty acid or salt thereof) (S) (positively charged silica fine particles + negatively charged silica fine particles + titanium oxide fine particles) -long chain fatty acid or salt thereof; (t) (positively charged silica fine particles + negatively charged silica fine particles) -long chain fatty acid or Examples thereof include salts thereof.

  The order of the multi-stage processes (a) to (t) is merely an example, and is not limited to these. Moreover, you may add the inorganic fine particle of said (vi) 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.

  As described above, in the toner of the present invention, the external additive strongly adheres to the toner base particles due to the work function of each external additive and the work function of the toner base particles in multi-stage processing. In the final stage, the effect of controlling the release of the external additive is further strengthened by the binding action of the long-chain fatty acid or its salt added with a higher share than the other stages. Furthermore, effects such as charging uniformity and long-term charging stability are enhanced, and charging stability is maintained even after repeated use. In addition, the toner has an anti-aggregation effect, a flow aid, a lubricant, etc., and the contact between the toner and the photoconductor causes long-chain fatty acids or salts thereof to migrate to the photoconductor surface, lubricating the photoconductor surface, and It is considered that the effect of preventing the body from being polished by the external additive on the toner surface is further exhibited.

  On the other hand, the conventional toner, for example, the toner described in Patent Document 1 above, is obtained by simultaneously adding positively chargeable silica fine particles and negatively chargeable silica fine particles. By simultaneously adding the silica fine particles and the negatively chargeable silica fine particles, the electrostatic attractive force between the toner base particles and the negatively chargeable silica fine particles is reduced, and the negatively chargeable silica fine particles are easily detached. it is conceivable that. Furthermore, the absence of long-chain fatty acids or salts thereof seems to be a cause of the inability to suppress the release of negatively charged and / or positively charged silica fine particles or titanium oxide fine particles.

  The toner of the present invention can be used in any type of image forming apparatus. An image forming apparatus using a one-component toner or an image forming apparatus using a two-component toner may be used. Further, it may be a contact developing type image forming apparatus or a non-contact type image forming apparatus. A one-component contact-type image forming apparatus that can use the toner of the present invention is described in detail in, for example, Patent Document 8. The image forming apparatus of the present invention includes a latent image carrier on which an electrostatic latent image typified by a photoreceptor is formed; toner is applied to the latent image carrier to develop the electrostatic latent image on the latent image carrier. At least a developing device having a toner carrying member typified by a developing roll to be conveyed; and a toner regulating member for regulating the amount of toner carried to the latent image carrying member by the toner carrying member. The toner of the present invention is accommodated in a toner accommodating portion, conveyed from the toner accommodating portion to a developing roll (toner carrier), and supplied to the photosensitive member (latent image carrier) via the developing roll (toner carrier). And transferred to form an image. The toner regulating member adjusts the toner supply amount so that excessive supply from the developing roll (toner carrier) to the photosensitive member (latent image carrier) is not performed.

Hereinafter, the present invention will be described based on examples. First, the toner evaluation method of the present invention will be described. Evaluation items and evaluation methods are as follows.
(A) Evaluation of Charge Amount and Charge Uniformity The toner charge amount was measured as follows using an E-SPART analyzer manufactured by Hosokawa Micron Corporation. The toner prepared in Examples and Comparative Examples and a carrier (KBN100 ferrite carrier manufactured by Hitachi Metals, Ltd.) were mixed so as to have a toner concentration of 0.1% by mass, and stirred at 100 rpm for 15 minutes to charge the toner. . Thereafter, the toner and the carrier were separated by blowing nitrogen gas onto the mixture of the toner and the carrier. Next, the charge amount (Q / m) for each toner is measured, and the measured toner is measured for at least 100 toner particles having an average particle diameter of ± 0.1 μm obtained by a Coulter counter. Is plotted on the X axis, and the total charge amount represented by the following equation is plotted on the Y axis as the total charge amount.

  Here, if toner particles having the same particle diameter and charge amount are plotted, when the number of toners and the total charge amount are plotted, a straight line passing through the origin with correlation coefficient = 1 should be obtained. The number of toners and the measured value of the total charge amount were plotted, and the deviation from the straight line was evaluated by the correlation coefficient.

(B) Irregular Toner Generation Rate Using the E-SPART analyzer of (1), the number of positively charged toners (reversely charged toners) that are irregular toners was measured to determine the irregular toner generation rate.

(C) Free rate of external additives (silica fine particles, titanium oxide fine particles) The free rate of external additives (silica fine particles, titanium oxide fine particles) was measured using PT1000 particle analyzer (manufactured by Yokogawa Electric Corporation). Was measured. Details of the method for measuring the liberation rate of the external additive are described in Patent Document 8. Briefly, this principle is to determine the liberation rate by introducing toner particles into plasma, exciting and emitting the toner particles, and measuring the intensity and time. For example, the isolation rate of SiO ₂ introduces toner particles SiO ₂ was externally added to the plasma, measuring the emission intensity of the SiO ₂ in the toner particles. From the light emission intensity, the particle diameter (equivalent particle diameter) of the true spherical particles is obtained assuming that the toner particles to which SiO ₂ is externally added are true spherical particles. Liberated SiO _2, similarly to the case of the toner particles, the equivalent diameter of SiO ₂ is determined from the emission intensity. However, since the emission intensity of free SiO ₂ is small, the equivalent particle size is small. Therefore, the toner particles are separated from the free external additive by comparing the equivalent particle diameters. Therefore, when the total number of detected external additives SiO ₂ is obtained and an individual having a small equivalent particle diameter is defined as the number of free external additive particles, the following expression (X) is obtained.

Further, SiO ₂ adhering to the toner particles emits light at the same time in synchronization with the toner particles, but SiO ₂ not adhering to the toner particles does not emit light at the same time as the toner particles and emits light with a time shift (asynchronous). ) To distinguish whether SiO ₂ is attached to or separated from the toner particles. Based on this measured value, the liberation rate is obtained by the following equation (Y).

  In this example, the method represented by the formula (Y) was adopted. In addition, when measuring the liberation rate of the titanium oxide fine particles, the titanium oxide fine particles may be caused to emit light in plasma and measured in the same manner. Further, the volume average particle diameter of the toner base particles can be obtained, for example, by emitting a colorant contained in the toner base particles in plasma and obtaining an equivalent particle diameter.

(D) Durability test The toner is put into a copier (LP-9300 manufactured by Seiko Epson Corporation), and 3000 sheets are printed with a 5% consumption printing pattern. The electrical resistivity was measured.

(Preparation of toner base particles)
100 parts by mass of styrene-acrylic binder resin, 3.5 parts by mass of red pigment CI12055, and 1.0 part by mass of chromium salicylate complex were respectively added to Henschel mixer 20B (Mitsui Mine Co., Ltd.), and uniform. Mixed. This mixture was melt-kneaded using a twin-screw kneading extruder (PCM-30 manufactured by Ikekai Kasei Co., Ltd.), cooled, and then pulverized by jet air using a jet pulverizer 200AFG (Hosokawa Micron Corporation). Next, toner base particles having a volume average particle diameter of 8.5 μm were prepared using an air classifier 100ATP (Hosokawa Micron Corporation).

(External additive)
Table 1 shows external additives that are externally added to the toner base particles in this example.

(External processing)
In the embodiment of the present invention, in the external addition process, a predetermined amount of an external additive is added to 100 parts by mass of the toner base particles, and the Z0S0 type is added using a Henschel mixer FM20B (Mitsui Mining Co., Ltd.). Using a stirring blade, stirring and mixing were performed.

  Hereinafter, (I) toner with externally added particles of negatively chargeable silica particles and long chain fatty acids or salts thereof, and (II) particles of negatively charged silica particles and long chain fatty acids or salts thereof having different average particle diameters. Toner added externally, (III) Toner added with negatively charged silica fine particles, titanium oxide fine particles and particles of long chain fatty acid or salt thereof, (IV) Negatively charged silica fine particles, positively charged silica fine particles and long chain Toner with externally added particles of fatty acid or a salt thereof and titanium dioxide fine particles as required, and (V) negatively charged silica fine particles, positively charged silica fine particles, titanium dioxide fine particles, and long chain fatty acids or salts thereof Each of the toners externally added with particles will be described.

(I) Toner with externally added particles of negatively chargeable silica fine particles and long chain fatty acids or salts thereof (Example 1)
100 parts by mass of the above prepared toner base particles are put into a Henschel mixer FM20B, and 1.0 part by mass of hydrophobic negatively chargeable silica RX200 (manufactured by Nippon Aerogel) is added thereto, and processing at 3000 rpm for 2 minutes is performed. went. Next, 0.2 parts by mass of magnesium stearate was added to this processed product, and the process was performed at 4000 rpm for 2 minutes to obtain toner A. Note that the gap between the rotating blades of the mixer and the mixer wall (hereinafter simply referred to as the gap) at this time was 5 mm in both treatments. The production conditions for Toner A are shown in Table 2. The share when particles comprising this long-chain fatty acid or salt thereof were externally added was about 1.3 times the share when other external additives were added.

(Comparative Example 1)
Toner a was obtained in the same manner as in Example 1 except that the external addition treatment of the negatively chargeable silica fine particles and the external addition treatment of magnesium stearate were performed under the same conditions. Table 2 shows the production conditions of the toner a.

(Example 2, Comparative Examples 2 to 4)
In the following, toner B of Example 2 and toners of Comparative Examples 2 to 4 (toners b to d) were produced according to the toner production conditions shown in Table 2. In Example 2, particles consisting of long-chain fatty acids or salts thereof were added externally by increasing the share by reducing the gap between the rotor blade and the mixing wall. The share at the time of additive addition was about 1.5 times.

  The toners A to B of the example and the toners a to d of the comparative example were evaluated. The results are shown in FIG. FIG. 1 is a diagram showing the correlation for toner B. FIG. Table 3 shows the number of toners and the total charge amount obtained from the plots as shown in FIG. 1 (other than the toner B are not shown) for the toners A and B of the examples and the toners a to d of the comparative example. The correlation coefficient and irregular toner generation rate are shown.

  The results in Table 3 show that the negatively chargeable silica fine particles are externally added first, and then the number of rotations of the stirring blade is increased to increase the share at the time of addition to externally add particles made of long chain fatty acids or salts thereof. The toner obtained in Example 1 and the toner obtained by externally adding a long-chain fatty acid or a salt thereof by reducing the gap between the mixer and the rotor blade to increase the share at the time of addition. Example 2) shows that the correlation coefficient between the number of toners and the total charge amount is 0.99 or more, and the generation rate of irregular toner is also low. That is, it was found that the charge amount for each toner was stable and the charge of the entire toner was uniform.

  On the other hand, when the share at the time of addition of the long-chain fatty acid or a salt thereof is the same as the share at the time of the addition of the negatively-charged silica fine particles (Comparative Example 1), Alternatively, the toner c (Comparative Example 3) obtained by reducing the gap at the time of addition of the salt and increasing the share has a lower correlation coefficient than the toner of the example, and the generation rate of irregular toner is also higher. I understood it.

  Furthermore, negatively chargeable silica fine particles and long chain fatty acids or salts thereof are added at the same time, and the same share as when treated for a longer time than usual (Comparative Example 2), but negatively chargeable silica fine particles are added first. In comparison with the case where particles comprising a long-chain fatty acid or a salt thereof are added later (Comparative Example 1), Comparative Example 1 has a higher correlation coefficient and a lower incidence of irregular toner. It can be seen that a toner having excellent charging uniformity can be obtained by adding negatively-charged silica fine particles and particles of a long-chain fatty acid or a salt thereof in this order. Further, comparing these comparative examples with the examples, it can be seen that the charging uniformity is further improved by increasing the share at the time of external addition of particles comprising a long-chain fatty acid or a salt thereof. Further, Comparative Example 4 in which no long-chain fatty acid or a salt thereof is added has a problem that the appearance rate of the positively charged toner is extremely high. This is presumably because the negatively charged silica fine particles are not fixed because no long chain fatty acid or salt thereof is added.

(II) Toner having externally added particles of negatively chargeable silica particles having different average particle diameters and long chain fatty acids or salts thereof (Example 3)
100 parts by mass of the toner base particles prepared above are charged into a Henschel mixer FM20B, and 1 part by mass of hydrophobic negatively charged silica RX200 (manufactured by Nippon Aerogel), which is a small particle size silica, is added to 3000 rpm, 2 Minute processing. Next, 1 part by mass of hydrophobic negatively-charged silica RX50 (manufactured by Nippon Aerogel Co., Ltd.), which is a large particle size silica, was added to this treated product, and the treatment was performed at 3000 rpm for 2 minutes. Finally, 0.2 parts by mass of magnesium stearate was added to this processed product, and the resulting mixture was processed at 4000 rpm for 2 minutes to obtain toner C. In addition, the space | interval (henceforth a gap) of the rotating blade of a mixer and a mixer wall at this time was 5 mm in all the processes. Table 4 shows the production conditions of Toner C.

(Comparative Example 5)
Toner e was obtained in the same manner as in Example 3 except that the external addition treatment conditions for magnesium stearate were 3000 rpm for 2 minutes, the same as the external addition treatment conditions for the negatively chargeable silica fine particles. Table 4 shows the production conditions of the toner e.

(Examples 4-6, Comparative Examples 6-8)
Hereinafter, toners D to F of Examples 4 to 6 and toners (toners f to h) of Comparative Examples 6 to 8 were manufactured according to the toner manufacturing conditions shown in Table 4.

  The toners C to F of the example and the toners e to h of the comparative example were evaluated. The results are shown in FIG. FIG. 2 is a diagram showing the correlation between the number of toners and the total charge amount for toner C. FIG. Table 5 shows the number of toners and the total charge amount obtained from the plots (not shown except for toner C) shown in FIG. 1 for the toners D to F of the example and the toners e to h of the comparative example. A correlation coefficient (hereinafter, sometimes simply referred to as a correlation coefficient) and an occurrence rate of irregular toner are shown.

  As shown in Table 5, externally added negatively chargeable silica fine particles in the order of small particle size silica-large particle size silica, and then increasing the rotation speed of the stirring blade to increase the share at the time of addition Toner C obtained by externally adding particles of fatty acid or a salt thereof (Example 3), or long chain fatty acid by increasing the share at the time of addition by reducing the gap (gap) between the mixer wall and the rotor blade Alternatively, the toner D (Example 4) obtained by externally adding the salt has a correlation coefficient of 0.99 or more between the number of toners and the total charge amount, and the generation rate of irregular toner is also low. I understand. That is, it can be seen that the charge amount for each toner is stable, and the charge of the entire toner is uniform.

  In addition, it was obtained by externally treating small particle silica and large particle silica at the same time, and then externally adding particles consisting of long chain fatty acids or salts thereof with a higher share than when negatively charged silica fine particles were added. In toners E and F (Examples 5 and 6, respectively), the correlation coefficient between the number of toners and the total charge amount is 0.99 or more, and the generation rate of irregular toner is also low. That is, it can be seen that the charge amount for each toner is stable, and the charge of the entire toner is uniform.

  On the other hand, when the share at the time of addition of the long-chain fatty acid or a salt thereof is the same as the share at the time of the addition of the negatively chargeable silica fine particles (Comparative Example 5), or the share at the time of the addition of the negatively chargeable silica fine particles Alternatively, when the share is higher than that at the time of addition of the salt (Comparative Example 7), the correlation coefficient is lower than that of the Example, and the occurrence rate of irregular toner is also increased.

  Further, when negatively-charged silica fine particles and particles comprising a long-chain fatty acid or a salt thereof are added simultaneously (Comparative Example 6: Toner f), the share of the particles comprising a long-chain fatty acid or a salt thereof is finally increased. Although the correlation function and the appearance rate of irregular toner are slightly higher than those of the examples to be added, the correlation coefficient is higher and the appearance rate of irregular toner is smaller than those of the other comparative examples. Further, comparing these comparative examples with the examples, it can be seen that the charging uniformity is further improved by increasing the share at the time of external addition of particles comprising a long-chain fatty acid or a salt thereof. Further, Comparative Example 8 in which no long-chain fatty acid or a salt thereof is added has a problem that the appearance rate of the positively charged toner is extremely high. This is presumably because the negatively charged silica fine particles are not strongly fixed to the toner base particles because no long chain fatty acid or salt thereof is added.

(III) Toner with externally added particles of negatively chargeable silica fine particles, titanium oxide fine particles and long chain fatty acids or salts thereof (Example 7)
100 parts by mass of the toner base particles prepared above were put into a Henschel mixer FM20B, and 1.0 part by mass of hydrophobic titanium oxide STT30S (manufactured by Titanium Industry) was added thereto, followed by treatment at 3000 rpm for 2 minutes. Next, 0.2 parts by mass of magnesium stearate was added to this processed product, and the processing was performed at 4000 rpm for 2 minutes, whereby toner G was obtained. In addition, the space | interval (henceforth a gap) of the rotating blade of a mixer and a mixer wall at this time was 5 mm in either process. The manufacturing process of the toner G is shown in Table 6.

(Comparative Example 9)
100 parts by mass of toner base particles were put into a Henschel mixer FM20B, 1.0 part by mass of hydrophobic titanium oxide STT30S was added, and a treatment at 3000 rpm for 2 minutes was performed. In order to increase the share without adding anything to this treated product, a treatment at 4000 rpm for 2 minutes was performed to obtain a toner i. Table 6 shows the production process of the toner i.

(Examples 8-11, Comparative Examples 10-12)
Hereinafter, toners H to K of Examples 8 to 11 and toners (Toners j to l) of Comparative Examples 10 to 12 were manufactured according to the toner conditions shown in Table 6.

  The toners G to K of the examples and the toners i to l of the comparative examples were evaluated. The results are shown in FIG. FIG. 3 is a diagram showing a correlation regarding the toner G. Table 7 shows the correlation coefficients obtained from the plots shown in FIG. 3 (other than the toner G are not shown) for the toners G to K of the example and the toners i to l of the comparative example, and irregular toners. Indicates the incidence.

  The results in FIG. 3 and Table 7 show that titanium oxide fine particles were externally added first, and then the rotation speed of the stirring blade was increased to increase the share at the time of addition to externally add particles composed of long-chain fatty acids or salts thereof. Toner G obtained in Example 7 and toner obtained by externally adding a long-chain fatty acid or a salt thereof by reducing the gap between the mixer and the rotor blade to increase the share at the time of addition In H (Example 8), the correlation coefficient between the number of toners and the total charge amount is 0.993 or more, and the generation rate of irregular toner is also low. That is, it can be seen that the charge amount for each toner is stable, and the charge of the entire toner is uniform.

  In addition, when adding titanium dioxide fine particles and long chain fatty acids or salts thereof, negatively charged silica fine particles (small particle size silica) are added first or simultaneously with titanium oxide fine particles, and then the number of revolutions of the stirring blade is increased. Thus, toners I to K (Examples 9 to 11) obtained by increasing the share at the time of addition and externally adding particles of a long-chain fatty acid or a salt thereof are the number of toners and the total charge amount. The correlation coefficient is 0.99 or more, and the occurrence rate of irregular toner is also low. That is, it can be seen that the charge amount for each toner is stable, and the charge of the entire toner is uniform.

  On the other hand, Toner i (Comparative Example 9) which was processed without adding magnesium stearate after addition of titanium oxide fine particles and further increasing the rotational speed had an extremely high release rate of titanium oxide. When this toner i and the toner G of Example 7 are compared, magnesium stearate is added with a high share at the end, so that the fine particles of titanium oxide are retained to increase the uniformity of charging, and irregular toner is generated. It became clear that was suppressed.

  Further, when titanium oxide fine particles and long chain fatty acids or salts thereof are sequentially added, but the share at the time of addition is the same (Comparative Example 10), or titanium oxide fine particles and long chain fatty acids or salts thereof are simultaneously used (that is, the same share). When added (Comparative Example 11), the correlation coefficient is slightly lower than that of the toners of Examples, and the generation rate of irregular toner is also increased. This suggests that it is preferable to add titanium oxide fine particles and then add a long-chain fatty acid or a salt thereof with the next highest share.

  Furthermore, toner 1 (Comparative Example 12) obtained by first adding titanium oxide fine particles with a high share, and then adding a long-chain fatty acid or a salt thereof with a lower share than when adding titanium oxide fine particles, It was found that the correlation coefficient was as low as 0.93 and the generation rate of irregular toner was high.

(IV) Toner in which negatively-charged silica fine particles, positively-charged silica fine particles, particles composed of long-chain fatty acid or a salt thereof, and titanium dioxide fine particles as necessary are externally added (Example 12)
100 parts by mass of the toner base particles prepared above were charged into a Henschel mixer FM20B, and 1 part by mass of hydrophobic negatively chargeable silica (RX200) was added thereto, followed by treatment at 3000 rpm for 2 minutes. Next, 0.2 parts by mass of magnesium stearate and 0.5 parts by mass of hydrophobic positively-charged silica (NA50H) are added to this processed product, followed by treatment at 4000 rpm for 2 minutes (two-stage treatment), and toner. L was obtained. In addition, the space | interval (henceforth a gap) of the rotating blade of a mixer and a mixer wall at this time was 5 mm in either process. Table 8 shows the production conditions of the toner L.

(Comparative Example 13)
100 parts by mass of toner base particles were charged into a Henschel mixer FM20B, and 1 part by mass of hydrophobic negatively charged silica RX200 (manufactured by Nippon Aerosil Co., Ltd.) was added thereto, followed by treatment at 3000 rpm for 2 minutes to obtain toner m. Table 8 shows the production conditions of the toner m.

(Examples 13-15, Comparative Examples 14-16)
The toners M to O of Examples 13 to 15 and the toners (toners n to p) of Comparative Examples 14 to 16 were manufactured according to the toner manufacturing conditions shown in Table 8 below.

The toners L to O of the example and the toners m to p of the comparative example were evaluated. The results are shown in FIG. FIG. 4 is a diagram illustrating a correlation regarding the toner L. Table 9, the toner m~p toner L~O and Comparative Example embodiments, as shown in FIG. 4 plots (
A correlation coefficient obtained from the toner L and the irregular toner is shown.

  From the results of Table 9, the toner m of Comparative Example 13 to which only negatively chargeable silica fine particles were added, and an example in which particles made of long-chain fatty acid or a salt thereof and positively chargeable silica fine particles were added thereto with an increased share. Comparing with the 12 toner L, it can be clearly seen that the toner L has a higher correlation coefficient r and a lower incidence of irregular toner. From this, finally, by adding particles consisting of long-chain fatty acids or salts thereof and positively chargeable silica fine particles, the charge becomes uniform and the negatively chargeable silica fine particles are firmly bound, that is, It turns out that the effect as a binder is exhibited.

  Further, when the toners of Examples 14 and 15 (toners N and O) and the toner n of Comparative Example 14 are compared, finally, particles of long-chain fatty acid or a salt thereof and positively charged silica fine particles are added at the time of external addition. When the ratio is increased and added, the correlation coefficient r increases and the generation rate of irregular toner also decreases. Further, the toners N and O have a higher correlation coefficient r than the toner o of Comparative Example 15 in which an external additive and particles of a long-chain fatty acid or a salt thereof are simultaneously externally added. The incidence is also decreasing. From these, multi-stage treatment, and finally increasing the market share and adding particles of long-chain fatty acids or their salts and positively chargeable silica fine particles, the effect of charging uniformity and binder effect is demonstrated. I understand that

Further, when comparing the toners L to O of Examples 12 to 15 and the toner n of Comparative Example 14, this result shows that the negatively charged silica fine particles having a small particle diameter-the negatively charged silica fine particles having a large particle diameter-the titanium oxide fine particles Toners N and O obtained by a multi-stage process in which particles having a long chain fatty acid or a salt thereof and positively charged silica fine particles are added in a higher share than these external additives are added in order. The correlation coefficient r was the highest and the irregular toner generation rate was extremely low. That is, it can be seen that by performing the multi-stage treatment of the present invention, the charge amount for each toner is stabilized, and the charge of the whole toner becomes uniform.

  Further, the negatively charged silica fine particles and titanium oxide fine particles were externally added with a higher share than in Examples 12 to 15, and finally, long-chain fatty acids or the like thereof with a share lower than the share when adding these external additives. When the salt particles and the positively charged silica fine particles were externally added (Comparative Example 16), the correlation coefficient r was low and the generation rate of irregular toner was relatively high. For these reasons, multi-stage treatment is performed when adding external additives, and finally particles made of long-chain fatty acids or salts thereof and positively-charged silica fine particles with a share higher than the share when adding these external additives. It can be seen that the method of the present invention for externally adding the toner and the toner obtained thereby are excellent.

(V) Toner in which negatively-charged silica fine particles, positively-charged silica fine particles, titanium dioxide fine particles, and particles comprising a long-chain fatty acid or a salt thereof are externally added (Example 16)
100 parts by mass of the toner base particles prepared above were put into a Henschel mixer FM20B, and 1 part by mass of each of hydrophobic negatively chargeable silica (RX200) and hydrophobic negatively chargeable silica (RX50) was added thereto at 3000 rpm, Treatment for 2 minutes was performed. Next, hydrophobic titanium oxide STT30S (manufactured by Titanium Industry Co., Ltd.) was added to the treated product, and a treatment at 3000 rpm for 2 minutes was performed. 0.5 parts by mass of hydrophobic positively-charged silica (NA50H) is added to the obtained processed product and treated at 3000 rpm for 2 minutes. Finally, 0.2 part by mass of magnesium stearate is added, and 4000 rpm, 2 The toner P was obtained by performing the process for 4 minutes (four-stage process). In addition, the space | interval (henceforth a gap) between the rotary blade of a mixer and a mixer wall at this time was 5 mm in any process. Table 10 shows the production conditions of the toner P.

(Comparative Example 17)
Toner q was obtained in the same manner as in Example 16 except that the fourth magnesium stearate was added at the same 1000 rpm for 2 minutes as other external additives. Table 10 shows the production conditions of the toner q.

(Examples 17 to 19, Comparative Example 18)
Hereinafter, toners Q to S of Examples 17 to 19 and toner (toner r) of Comparative Example 18 were manufactured according to the toner manufacturing conditions shown in Table 10.

  The toners P to S of the example and the toners q to r of the comparative example were evaluated. The results are shown in FIG. FIG. 5 is a diagram showing a correlation regarding the toner P. Table 11 shows the correlation coefficient r obtained from the plots shown in FIG. 5 (not shown except for the toner P) and irregular toners for the toners P to S of the example and the toners q to r of the comparative example. The rate of occurrence and the respective liberation rates of silica and titanium are shown. For the toner P of Example 16 and the toner r of Comparative Examples 17 and 18, a 3000 sheet printing durability test was performed to obtain a correlation coefficient r representing the uniformity of the charge amount after the durability test.

  Toner P of Example 16 in which the share at the time of addition of particles comprising a long chain fatty acid or a salt thereof is increased by the number of revolutions, Toner S of Example 19 in which the gap between the mixing wall and the rotor blade is reduced to increase the share, Toner q of Comparative Example 17 in which the share at the time of adding particles comprising a long-chain fatty acid or a salt thereof was weakened, and a comparison at which the share at the time of adding particles comprising a long-chain fatty acid or a salt thereof was made the same as that of other external additives When the toner r of Example 18 is compared, the toner P and toner S of the example are excellent in charging uniformity, the ratio of the positively chargeable toner that is an irregular toner is small, and the liberation rate of silica and titanium is also the same as that of the comparative example. It can be seen that it is smaller than toner q and toner r (see Table 11). From this result, finally, by adding particles made of long-chain fatty acids or salts thereof with a high share, the charge becomes uniform and the negatively charged silica fine particles are firmly bound, that is, as a binder. It can be seen that the effect of.

  Further, the correlation coefficient r after the endurance test was almost the same as that of the toner P of Example 16, whereas the correlation coefficient r of the toner q of Comparative Example 17 was greatly reduced. For this reason, finally, by adding particles made of long-chain fatty acids or salts thereof with a high share, negative or positively chargeable silica fine particles and titanium oxide strongly adhere to the toner base particles, and are charged even after the durability test. It was found that the uniformity was maintained, and finally, the effect of adding particles consisting of a long-chain fatty acid or a salt thereof with a high share became even clearer.

  Further, as can be seen from the toner Q of Example 17 and the toner R of Example 18, titanium oxide fine particles and / or positively-charged silica fine particles are added to increase the market share in addition to particles made of long-chain fatty acids or salts thereof. As a result, it has become clear that external additives such as negatively chargeable silica fine particles, titanium oxide fine particles, and positively chargeable silica fine particles adhere firmly.

  The toner of the present invention obtained by adding an external additive in a multi-stage process and increasing the share at the final stage and externally adding a long-chain fatty acid or a salt thereof has a stable charge amount for each toner. The entire charging becomes uniform, and the charging stability is maintained even in repeated use, and since the generation rate of irregular toner is low, a stable image can be provided. Therefore, the toner of the present invention is widely used as an electrophotographic toner.

FIG. 6 is a diagram illustrating a relationship between the number of toners and the total charge amount when the toner A of the present invention is charged. It is a figure which shows the relationship between the toner number when charging the toner C of this invention, and total charge amount. It is a figure which shows the relationship between the toner number when charging the toner G of this invention, and total charge amount. It is a figure which shows the relationship between the toner number when charging the toner L of this invention, and total charge amount. It is a figure which shows the relationship between the toner number when charging the toner Q of this invention, and total charge amount.

Claims (22)

A toner in which two or more external additives are added to toner base particles containing a binder resin and a colorant, wherein the external additives are added by multi-stage treatment, and in the final stage of the multi-stage treatment, a long-chain fatty acid A toner obtained by adding an external additive containing a metal salt at a higher share than in other stages. The external additive is added using a mixer having rotor blades, and by controlling the rotational speed of the rotor blades, the external additive containing a metal salt of a long-chain fatty acid in the final stage is more than in other stages. The toner according to claim 1, wherein the toner is added with a high share. The external additive is added using a mixer having rotor blades, and an external additive containing a metal salt of a long-chain fatty acid in the final stage is controlled by controlling the distance between the rotor blades and the mixer wall. The toner according to claim 1, wherein the toner is added with a higher share than the other stages. At least one external additive selected from the group consisting of negatively chargeable silica fine particles, titanium oxide fine particles and positively chargeable silica fine particles is added to the toner base particles, and an external additive containing a metal salt of a long-chain fatty acid in the final stage. The agent is added at a higher share than the other stages.
The toner according to any one of the above items. In the multi-stage treatment, negatively-charged silica fine particles are first added to the toner base particles, and an external additive containing a metal salt of a long-chain fatty acid is added at a higher share than the other stages in the final stage.
The toner according to claim 4. In the multi-stage treatment, negatively-charged silica fine particles are added first, then titanium oxide fine particles are added, and an external additive containing a metal salt of a long-chain fatty acid is added at a higher share than other steps in the final stage. The toner according to claim 4. In the multi-stage process, is first titanium oxide fine particles added, at the final stage of a long chain fatty acid
The toner according to claim 4, wherein an external additive containing a metal salt is added with a higher share than in other stages. In the multistage treatment, negatively chargeable silica fine particles and titanium oxide fine particles are first added, and an external additive containing a metal salt of a long-chain fatty acid is added at a higher share in the final stage than in other stages. Item 5. The toner according to Item 4. In the multi-stage treatment, at least one external additive selected from the group consisting of negatively chargeable silica fine particles and titanium oxide fine particles is added, and then positively chargeable silica fine particles are added,
The metal salt of a long-chain fatty acid is added at a higher share in the final stage than in other stages.
The toner described in 1. In the multistage treatment, at least one external additive selected from the group consisting of negatively charged silica fine particles and titanium oxide fine particles is first added, and in the final step, positively charged silica fine particles and metal salts of long chain fatty acids are added. The additive is added at a higher share than the step of claim 4.
The toner described in 1. A method for producing a toner comprising a step of externally adding two or more external additives to toner base particles containing a binder resin and a colorant by a multi-stage treatment, wherein a metal of a long-chain fatty acid is used in the final stage of the multi-stage treatment.
A method comprising a step of adding an external additive containing a salt with a higher share than other steps. The external additive is added using a mixer having rotor blades, and by controlling the rotational speed of the rotor blades, the external additive containing a metal salt of a long-chain fatty acid is added to the other stage in the final stage. 12. The method of claim 11, comprising the step of adding at a higher share. The external additive is added using a mixer having rotor blades, and an external additive containing a metal salt of a long-chain fatty acid in the final stage is controlled by controlling the distance between the rotor blades and the mixer wall. 12. The method of claim 11, comprising the step of adding the agent with a higher share than the other stages. A step of adding to the toner base particles at least one external additive selected from the group consisting of negatively chargeable silica fine particles, titanium oxide fine particles and positively chargeable silica fine particles, and a metal salt of a long-chain fatty acid in the final stage Including the process of adding external additives at a higher share than other stages,
14. A method according to any one of claims 11 to 13. First, the negatively chargeable silica fine particles are added to the toner base particles, and long in the final stage.
The method of Claim 14 including the process of adding the external additive containing the metal salt of a chain fatty acid with a higher share than another stage. The negative chargeable silica fine particles are first added to the toner base particles, then the titanium oxide fine particles are added, and the external additive containing a metal salt of a long-chain fatty acid in the final stage has a higher share than the other stages. 15. The method according to claim 14, comprising the step of adding. 15. The method according to claim 14, comprising the step of adding the titanium oxide fine particles first and the step of adding an external additive containing a metal salt of a long-chain fatty acid at a final stage with a higher share than the other stages. The method includes the step of first adding the negatively chargeable silica fine particles and the titanium oxide fine particles, and the step of adding an external additive containing a metal salt of a long-chain fatty acid at a final stage with a higher share than the other stages. The method described in 1. A step of adding at least one external additive selected from the group consisting of the negatively chargeable silica fine particles and the titanium oxide fine particles, a step of adding positively chargeable silica fine particles, and a metal salt of a long-chain fatty acid in the final step 15. The method of claim 14, comprising the step of adding at a higher share than the other stages. A step of adding at least one external additive selected from the group consisting of the negatively chargeable silica fine particles and the titanium oxide fine particles, and then the positively chargeable silica fine particles and the metal salt of the long-chain fatty acid in another step. 15. The method of claim 14, comprising the step of adding with a higher share.   An image forming apparatus comprising the toner according to claim 1. A latent image carrier on which an electrostatic latent image is formed; a toner carrier that transports toner to the latent image carrier to develop the electrostatic latent image on the latent image carrier; and the toner carrier The image forming apparatus according to claim 21, further comprising: a developing unit having a toner regulating member that regulates an amount of toner conveyed to the latent image carrier.

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