JP2005062904A - Electrostatic charge image developing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner excellent in fixability and anti-offsetting property. <P>SOLUTION: The electrostatic charge image developing toner comprises aggregates of particles containing at least primary particles of a polymer. The primary particles of the polymer have a structure which substantially encapsulates wax. The primary particles of the polymer are obtained by previously preparing wax emulsion and using the wax emulsion as a seed to proceed to emulsion polymerization. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrostatic charge image developing toner used in electrophotographic copying machines and printers. More specifically, the present invention relates to a toner for developing an electrostatic charge image, which is excellent in fixability, offset resistance and blocking resistance, and has good gloss and OHP transparency of the obtained image.

  Toner for electrostatic image development that has been widely used in electrophotography in the past is a mixture of a styrene / acrylate copolymer and a colorant such as carbon black or pigment, a charge control agent, and / or a magnetic material. It has been produced by melt-kneading with an extruder and then crushing and classifying. However, the conventional toner obtained by the melt-kneading / pulverization method as described above has a limit in controlling the particle size of the toner, and substantially produces a toner having an average particle size of 10 μm or less, particularly 8 μm or less with a high yield. However, it was difficult to achieve the high resolution required for electrophotography in the future.

Further, in order to achieve low-temperature fixability, a method of blending a wax having a low softening point into the toner during kneading has been proposed, but in the kneading / pulverization method, blending of about 5% is the limit, A toner having sufficient low-temperature fixing performance could not be obtained. Patent Document 1 proposes a toner production method using an emulsion polymerization / aggregation method in order to overcome the problem of particle size control and achieve high resolution. However, even in this method, there is a limit to the amount of wax that can be introduced in the coagulation step, and a sufficient improvement effect has not been obtained with respect to low-temperature fixability. That is, when the present inventors examined the amount of added wax based on the patent, when the amount of added wax is increased, the particle size distribution of the obtained toner becomes two peaks or less than 1 μm. There was a problem that fine powder remained, and a classification step was required after the aggregation step. The method disclosed in Patent Document 2 is a method capable of obtaining agglomerated particles having a narrow particle size distribution by adding an organic solvent that is infinitely soluble in water simultaneously with the aggregating agent in the aggregating step. There are problems such as poor reproducibility due to the large number and heavy burden of wastewater treatment.
JP-A 63-186253 JP-A-6-329947

  An object of the present invention is to provide a novel toner that overcomes the disadvantages of conventionally used toners for developing electrostatic images and satisfies high resolution, low-temperature fixability, and offset resistance.

  As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by using polymer primary particles obtained by emulsion polymerization using a wax emulsion as a seed, and have reached the present invention. That is, the present invention is characterized in that, in an electrostatic image developing toner mainly composed of particle aggregates containing polymer primary particles, the polymer primary particles substantially have a structure containing a wax inside. The toner for developing an electrostatic charge image is as follows.

  In the present invention, by encapsulating the wax in the polymer primary particles, it is possible to obtain a toner having a sufficient non-offset region even in the heating roller fixing method and having good OHP transparency and image glossiness.

  Hereinafter, the present invention will be described in detail. As the wax used as a seed in the present invention, any of known waxes can be used. Specifically, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene, paraffin wax, Ester wax having a long chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate, vegetable wax such as hydrogenated castor oil carnauba wax, ketone having a long chain alkyl group such as distearyl ketone, alkyl group And higher fatty acids such as stearic acid, long-chain fatty acid alcohols, long-chain fatty acid polyhydric alcohols such as pentaerythritol, and partial ester forms thereof, higher fatty acid amides such as oleic acid amide and stearic acid amide, etc. The Among these waxes, a wax having a melting point of 100 ° C. or lower is more preferable in order to improve fixability, and a more preferable wax has a melting point in the range of 40-90 ° C., particularly preferably in the range of 50-80 ° C. It is. When the melting point exceeds 100 ° C., the effect of reducing the fixing temperature is poor.

  The wax fine particles used in the present invention are obtained by emulsifying the wax in the presence of at least one emulsifier selected from known cationic surfactants, anionic surfactants, and nonionic surfactants. Two or more of these surfactants may be used in combination. Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.

  Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.

  Further, specific examples of nonionic surfactants include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, monodecanoyl And sucrose.

  In the present invention, these waxes are dispersed in the presence of an emulsifier to form an emulsion and subjected to resin seed polymerization. The average particle size of the wax emulsion is preferably 0.01 μm to 3 μm, more preferably 0.03 to 1 μm, and particularly preferably 0.05 to 0.8 μm. The average particle diameter can be measured using, for example, Nikkiso Microtrac UPA. When the average particle size of the wax emulsion is larger than 3 μm, the average particle size of the polymer particles obtained by seed polymerization becomes too large, so that it is unsuitable for applications requiring high resolution as a toner. On the other hand, when the average particle diameter of the emulsion is smaller than 0.01 μm, the wax content in the polymer primary particles after seed polymerization becomes too low, so that the effect of the wax becomes low.

  In seed emulsion polymerization in the presence of a wax emulsion, by adding a monomer having a polar group (a monomer having an acidic polar group or a monomer having a basic functional group) and another monomer sequentially, the wax is added. Polymerization proceeds in an emulsion containing At this time, the monomers may be added separately, or a plurality of monomers may be mixed and added in advance. Further, it is possible to change the monomer composition during the monomer addition. The monomer may be added as it is, or may be added as an emulsion mixed and adjusted in advance with water or a surfactant. As the surfactant, one or two or more combined systems are selected from the above surfactants.

  In proceeding with the seed emulsion polymerization, a certain amount of emulsifier may be added to the wax emulsion. Further, the addition timing of the polymerization initiator may be any before the monomer addition, at the same time as the monomer addition, after the monomer addition, or may be a combination of these addition methods.

  The polymer primary particles obtained as described above are polymer particles substantially including a wax, and the morphology thereof takes any form such as a core-shell type, a phase separation type, and an occlusion type. It may be a mixture of these forms. Particularly preferred is the core-shell type. The wax is usually used in an amount of 1 to 40 parts by weight, preferably 2 to 35 parts by weight, and more preferably 5 to 30 parts by weight with respect to 100 parts by weight of the binder resin. In addition, components other than wax, such as pigments, charge control agents, etc., may be used as seeds at the same time within the scope of the present invention. Further, a colorant may be used by dissolving or dispersing in a monomer or wax.

  As the monomer having an acidic polar group used in the present invention, a monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, a monomer having a sulfonic acid group such as sulfonated styrene, Etc.

  The monomer having a basic polar group has amino groups such as aminostyrene and quaternary salts thereof, nitrogen-containing heterocyclic ring-containing monomers such as vinylpyridine and vinylpyrrolidone, and dimethylaminoethyl acrylate and diethylaminoethyl methacrylate. (Meth) acrylic acid esters and (meth) acrylic acid esters having ammonium salts obtained by quaternizing these amino groups, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N- Examples include dipropylacrylamide, N, N-dibutylacrylamide, and acrylic acid amide.

  Other comonomers include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene, methyl acrylate, ethyl acrylate , Propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hydroxyethyl methacrylate And (meth) acrylic acid esters such as ethylhexyl methacrylate. Of these, styrene, butyl acrylate, and the like are particularly preferable.

  These monomers are used alone or in combination, and in this case, the glass transition temperature of the polymer is preferably 40 to 80 ° C. If the glass transition temperature exceeds 80 ° C., the fixing temperature may become too high, or the deterioration of OHP transparency may be a problem. On the other hand, if the glass transition temperature of the polymer is less than 40 ° C., the storage stability of the toner Becomes too bad and causes problems. In the present invention, acrylic acid is suitably used as the monomer having an acidic polar group, and styrene, acrylic acid ester, and methacrylic acid ester are suitably used as the other monomers.

Polymerization initiators include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate, and redox initiators that combine these persulfates as a component with a reducing agent such as acidic sodium sulfite, hydrogen peroxide Water-soluble polymerization initiators such as 4,4′-azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydroperoxide, etc., and reduction of ferrous salts etc. using these water-soluble polymerizable initiators as one component Redox initiator systems in combination with agents, benzoyl peroxide, 2,2′-azobis-isobutyronitrile, and the like are used. These polymerization initiators may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

  In the present invention, a known chain transfer agent can be used if necessary. Specific examples of such a chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, tetrachloride. Carbon, trichlorobromomethane, and the like. The chain transfer agent may be used alone or in combination of two or more, and is used in an amount of 0 to 5% by weight based on the polymerizable monomer.

The average particle diameter of the polymer primary particles is usually in the range of 0.05 μm to 3 μm, preferably 0.1 μm to 1 μm, more preferably 0.1 μm to 0.5 μm. The average particle diameter can be measured using, for example, UPA. When the particle size is smaller than 0.05 μm, it is not preferable because it is difficult to control the aggregation rate. On the other hand, if the particle size is larger than 3 μm, the particle size of the toner obtained by agglomeration becomes too large, so that it is not suitable for applications requiring high resolution as a toner.

  In the present invention, when obtaining the polymer primary particles, the pigment may be used as a seed simultaneously with the wax, or the colorant may be used by dissolving or dispersing in the monomer or wax, but it is colored simultaneously with the polymer primary particles. The toner primary particles are preferably agglomerated to form associated particles to obtain a toner. At this time, polymer primary particles encapsulating wax are used, but two or more kinds of polymer primary particles may be used as necessary. Moreover, as a coloring agent used here, any of an inorganic pigment, an organic pigment, an organic dye may be sufficient, or these combination may be sufficient. Specific examples of these include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, disazo. Any known dyes and pigments such as those based on azo dyes and condensed azo dyes can be used alone or in combination. In the case of a full color toner, it is preferable to use benzidine yellow for yellow, monoazo and condensed azo dyes, magenta for quinacridone and monoazo dyes, and cyan for phthalocyanine blue. The colorant is usually used in an amount of 3 to 20 parts by weight with respect to 100 parts by weight of the binder resin.

  These colorants are also emulsified in water in the presence of an emulsifier and used in the form of an emulsion. The average particle diameter is preferably 0.01 to 3 μm. As the charge control agent, any known one can be used alone or in combination. Considering color toner adaptability (the charge control agent itself is colorless or light color and there is no color tone damage to the toner), the positive chargeability is quaternary ammonium salt compound, and the negative charge is salicylic acid or alkyl salicylic acid chromium. Metal salts with zinc, aluminum and the like, metal complexes, metal salts of benzylic acid, metal complexes, amide compounds, phenol compounds, naphthol compounds, phenolamide compounds and the like are preferable. The amount used may be determined according to the desired charge amount for the toner, but is usually used in an amount of 0.01 to 10 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the binder resin.

  In the present invention, when obtaining the polymer primary particles, the charge control agent may be used as a seed simultaneously with the wax, or the charge control agent may be used by dissolving or dispersing in a monomer or wax. At the same time, the primary particles of the charge control agent are preferably agglomerated to form associated particles to obtain a toner. In this case, the charge control agent is also used as an emulsion having an average particle size of 0.01 to 3 μm in water. The timing of the addition may be simultaneously added and aggregated in the step of aggregating the polymer primary particles and the colorant primary particles, or may be added at the stage where these primary particles are associated to form secondary particles. Further, it may be added after the associated particles have grown to the final particle size of the toner.

In producing the toner of the present invention, after the aggregated particle size has grown substantially to the final toner particle size, a binder resin emulsion of the same or different type is further added to adhere the particles to the surface. By doing so, it is possible to modify the toner properties near the surface. Further, the toner of the present invention can be used together with additives such as a fluidizing agent, if necessary. Specific examples of such fluidizing agents include fine particles such as hydrophobic silica, titanium oxide, and aluminum oxide. A powder can be mentioned, Usually, 0.01-5 weight part with respect to 100 weight part of binder resin, Preferably 0.1-3 weight part is used.

  Further, the toner of the present invention includes an inorganic fine powder such as magnetite, ferrite, cerium oxide, strontium titanate, and conductive titania, a resistance adjuster such as styrene resin and acrylic resin, and a lubricant as an internal or external additive. Used. The amount of these additives to be used may be appropriately selected depending on the desired performance, and is usually about 0.05 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  The toner for developing an electrostatic charge image of the present invention may be used in any form of a two-component developer or a non-magnetic one-component developer. When used as a two-component developer, the carrier may be a magnetic substance such as iron powder, magnetite powder or ferrite powder, or a known material such as a resin coating on the surface thereof or a magnetic carrier. As the coating resin of the resin coating carrier, generally known styrene resin, acrylic resin, styrene acrylic copolymer resin, silicone resin, modified silicone resin, fluororesin, or a mixture thereof can be used.

The present invention will be specifically described below with reference to examples. In the following examples, “parts” means “parts by weight”. Moreover, the average particle diameter and molecular weight of the polymer particles were measured by the following methods, respectively.
Average particle diameter: measured by Nikkiso Microtrac UPA or Coulter Coal Counter Multisizer II type.
Weight average molecular weight: Measured by gel permeation chromatography (GPC). (Solvent: THF, calibration curve: standard polystyrene)

The obtained toner was subjected to a fixing test by the following method. Recording paper carrying an unfixed toner image was prepared, the surface temperature of the heating roller was changed from 100 ° C. to 190 ° C., conveyed to the fixing nip, and the fixing state when discharged was observed. A fixing temperature region is defined as a temperature region in which toner on the heating roller is not offset during fixing and the toner on the recording paper for fixing is sufficiently adhered to the recording paper. When the lower limit temperature of the fixing temperature at which this offset does not occur is TL and the upper limit temperature is TU, TU-TL is the fixing temperature range. The fixing machine used the following method 1 or 2.
(Method 1) The heating roller of the fixing machine was evaluated with a release layer made of FEP and a nip width of 5 mm. (Method 2) The heating roller of the fixing machine was evaluated with a release layer made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) and a nip width of 4 mm.

<Production of polymer primary particles>
The following wax emulsion and demineralized water were charged into a glass reactor equipped with a stirrer, a heating / cooling device, a concentrating device, and raw material / auxiliary charging devices, and the temperature was raised to 90 ° C. under a nitrogen stream.

(Table 1)
Behenyl behenate emulsion (average particle size 0.4 μm) 21.3 parts (as solids)
And)
Deionized water (including water in wax emulsion) 404.9 parts

  Thereafter, the following monomers, an aqueous emulsifier solution and an initiator were added, and emulsion polymerization was performed for 5 hours.

(Table 2)
(Monomers)
Styrene 64 parts butyl acrylate 36 parts acrylic acid 3 parts trichlorobromomethane 1.3 parts emulsifier aqueous solution 12 parts (initiator)
2% aqueous hydrogen peroxide solution 43.0 parts 2% aqueous ascorbic acid solution 43.0 parts

After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle emulsion. (Hereinafter abbreviated as resin emulsion A.)
The average particle diameter of the obtained emulsion was 257 nm, and the weight average molecular weight of the polymer was 42,000. When the cross section of the obtained emulsion was observed with TEM, it was observed that the wax was encapsulated with the resin.
<Formation of associated particles (preparation of toner) and evaluation>

(Table 3)
Resin emulsion A 120 parts (as solids)
Charge control agent Bontron S-34 (10% dispersion) 0.65 parts (as solids)
6.7 parts aqueous dispersion of phthalocyanine blue (as solids)

  While dispersing and stirring the above mixture with a disperser, an aqueous sodium chloride solution (9 parts as a solid content) was added, and the mixture was kept at 20 ° C. for 1.5 hours. Thereafter, the temperature was raised to 45 ° C. with further stirring and held for 0.5 hour. To further increase the bond strength of the associated particles, the temperature was raised to 95 ° C. and held for 5 hours. The resulting slurry of associated particles was cooled, filtered through a Kiriyama funnel, washed with water, and lyophilized to obtain a toner having an average particle size of 6.9 μm. When the toner thus obtained was evaluated by Method 2, it was fixed at 115 to 190 ° C. or higher.

  Resin emulsion as in Example 1 except that a resin emulsion (referred to as resin emulsion B) is produced using purified paraffin (average particle size 0.42 μm) emulsified with a nonionic surfactant as a wax emulsion. Toner particles were produced. The toner thus obtained had an average particle diameter of 6.1 μm, and when this was evaluated by Method 2, it was fixed at 100 to 190 ° C. or more.

<Production of polymer primary particles>
The following wax emulsion and demineralized water were charged into a glass reactor equipped with a stirrer, a heating / cooling device, a concentrating device, and raw material / auxiliary charging devices, and the temperature was raised to 90 ° C. under a nitrogen stream.

(Table 4)
Behenyl behenate emulsion (average particle size 0.8 μm) 10.6 parts (as solids)
And)
Deionized water (including water in wax emulsion) 352.3 parts

Thereafter, the following monomers, an aqueous emulsifier solution and an initiator were added, and emulsion polymerization was performed for 5 hours.

(Table 5)
(Monomers)
Styrene 75 parts Butyl acrylate 25 parts Acrylic acid 3 parts Trichlorobromomethane 0.5 part Emulsifier aqueous solution 26 parts (initiator)
2% aqueous hydrogen peroxide solution 43.2 parts 2% aqueous ascorbic acid solution 43.2 parts

After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle emulsion. (Hereinafter abbreviated as resin emulsion C.)
The average particle diameter of the obtained emulsion was 244 nm, and the weight average molecular weight of the polymer was 59000. When the cross section of the obtained emulsion was observed with TEM, it was observed that the wax was encapsulated with the resin.
<Formation of associated particles (preparation of toner) and evaluation>

(Table 6)
110 parts of resin emulsion C (as solids)
Charge control agent phenolamide compound (20% dispersion) 0.65 parts (as solids)
6.7 parts aqueous dispersion of phthalocyanine blue (as solids)

While dispersing and stirring the above mixture with a disperser, an aqueous aluminum sulfate solution (0.4 parts as a solid content) was added, and the mixture was kept at 20 ° C. for 1.5 hours. Thereafter, the temperature was raised to 60 ° C. with further stirring and held for 0.5 hours, and further raised to 95 ° C. and held for 5 hours in order to further increase the bond strength of the associated particles. The resulting slurry of associated particles was cooled, filtered through a Kiriyama funnel, washed with water, and freeze-dried to obtain a toner. When the toner thus obtained was evaluated by Method 2, it was fixed at 140 to 190 ° C. or more.
(Comparative example)

<Production of polymer primary particles>
Emulsion polymerization was carried out in the same manner as in Example 3 except that the following emulsifier and demineralized water were charged into a glass reactor equipped with a stirrer, heating / cooling device, concentrating device, and raw material / auxiliary charging device. .

(Table 7)
Dodecylbenzenesulfonic acid 0.3 part Deionized water 315.3 parts

After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle emulsion. (Hereinafter abbreviated as resin emulsion D.)
The average particle diameter of the obtained emulsion was 219 nm, and the weight average molecular weight of the polymer was 60000.

<Formation of associated particles (preparation of toner) and evaluation>
Example 3 except that Resin Emulsion C was changed to 100 parts of Resin Emulsion D (as solids) and 10 parts of behenyl behenate emulsion (as solids) emulsified with sodium dodecylbenzenesulfonate (average particle size 0.44 μm). Thus, toner particles were produced. The toner thus obtained had an average particle size of 6.0 μm, and when this was evaluated by Method 2, it was fixed at 152 to 190 ° C. or more. As described above, when Example 3 using the toner in which the wax is encapsulated and Comparative Example 1 using the toner co-aggregated at the time of aggregation of the wax are compared, the lower limit fixing temperature TL is higher in Comparative Example 1. The fixing temperature range was also reduced.
(Comparative Example 2)

Toner particles were produced in the same manner as in Example 3 except that the resin emulsion C was changed to 100 parts (as solid content) of the resin emulsion D. The toner thus obtained had an average particle size of 5.3 μm, and when this was evaluated by Method 2, it was fixed at 160 to 190 ° C. or more. As described above, when Example 3 using the toner including the wax is compared with Comparative Example 2 using the toner without the wax, the lower limit fixing temperature TL is higher in Comparative Example 2, and the fixing temperature width is also larger. It has become smaller.

  Resin emulsion E and toner particles were produced in the same manner as in Example 3 except that the monomers were changed as follows.

(Table 8)
(Monomers)
Styrene 79 parts Butyl acrylate 21 parts Acrylic acid 3 parts Trichlorobromomethane 0.5 part

The toner thus obtained had an average particle size of 8.1 μm, and when this was evaluated by Method 2, it was fixed at 148 to 190 ° C. or more.
(Comparative Example 3)

  Resin emulsion F and toner particles were produced in the same manner as in Comparative Example 1 except that the monomers were changed as follows.

(Table 9)
(Monomers)
Styrene 79 parts Butyl acrylate 21 parts Acrylic acid 3 parts Trichlorobromomethane 0.5 part

The toner thus obtained had an average particle size of 5.9 μm. When this was evaluated by Method 2, it was fixed at 168 to 190 ° C. or more. As described above, when Example 4 using the toner encapsulating the wax and Comparative Example 3 using the toner co-aggregated with the wax during aggregation, Comparative Example 3 has a higher fixing lower limit temperature TL, The fixing temperature range was also reduced.
(Comparative Example 4)

Toner particles were produced in the same manner as in Example 4 except that the resin emulsion E was changed to 100 parts (as solid content) of the resin emulsion F. The toner thus obtained had an average particle size of 4.9 μm, and when this was evaluated by Method 2, it was fixed at 170 to 190 ° C. or more. As described above, when Example 4 using the toner containing the wax is compared with Comparative Example 4 using the toner without the wax, the lower limit fixing temperature TL is higher in the comparative example 4, and the fixing temperature width is also higher. It has become smaller.

<Production of polymer primary particles>
The following wax emulsion and demineralized water were charged into a glass reactor equipped with a stirrer, a heating / cooling device, a concentrating device, and raw material / auxiliary charging devices, and the temperature was raised to 90 ° C. under a nitrogen stream.

(Table 10)
Behenyl behenate emulsion (average particle size 0.42 μm) 21.3 parts (as solids)
Sodium dodecylbenzenesulfonate 0.5 part Deionized water (including water in wax emulsion) 396.9 parts

  Thereafter, the following monomers, an aqueous emulsifier solution and an initiator were added, and emulsion polymerization was performed for 5 hours.

(Table 11)
(Monomers)
Styrene 72 parts Butyl acrylate 28 parts Acrylic acid 3 parts Trichlorobromomethane 0.5 part Emulsifier aqueous solution 26 parts (initiator)
2% aqueous hydrogen peroxide solution 43.2 parts 2% aqueous ascorbic acid solution 43.2 parts

After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle emulsion. (Hereinafter abbreviated as resin emulsion G.)
The average particle diameter of the obtained emulsion was 144 nm, and the weight average molecular weight of the polymer was 74000. When the cross section of the obtained emulsion was observed with TEM, it was observed that the wax was encapsulated with the resin. Similarly, emulsion polymerization is carried out in the same manner as the resin emulsion G, except that the following wax emulsion is charged into a glass reactor equipped with a stirrer, heating / cooling device, concentrating device, and each raw material / auxiliary charging device. H was obtained.

(Table 12)
Alkyl-modified silicone emulsion (average particle size 0.27 μm) 21.1 parts (as solids)
392.2 parts deionized water (including water in wax emulsion)

The average particle diameter of the obtained emulsion was 284 nm, and the weight average molecular weight of the polymer was 150,000. When the cross section of the obtained emulsion was observed with TEM, it was observed that the wax was encapsulated with the resin.
<Formation of associated particles (preparation of toner) and evaluation>

(Table 13)
60 parts of resin emulsion G (as solids)
60 parts of resin emulsion H (as solid content)
Charge control agent Bontron S-34 (10% dispersion) 0.65 parts (as solids)
6.7 parts aqueous dispersion of phthalocyanine blue (as solids)

  The above mixture was held at 20 ° C. for 1.5 hours while being dispersed and stirred with a disperser. Thereafter, the temperature was raised to 55 ° C. with further stirring and held for 0.5 hour, and the temperature was raised to 95 ° C. and held for 5 hours to further increase the bond strength of the associated particles. The resulting slurry of associated particles was cooled, filtered through a Kiriyama funnel, washed with water, and freeze-dried to obtain a toner. The toner thus obtained had an average particle size of 5.9 μm. When this was evaluated by Method 1, it was fixed at 115 to 187 ° C.

  Except for producing a resin emulsion (referred to as Resin Emulsion I) using an emulsion obtained by emulsifying glyceride montanate with a nonionic surfactant (average particle size 0.27 μm) as a wax emulsion, the same procedure as in Example 5 was performed. A resin emulsion and toner particles were produced. The toner thus obtained was evaluated by Method 1 and fixed at 120 to 190 ° C.

As a wax emulsion, a polyethylene emulsion (Hitech E5403B manufactured by Toho Chemical Co., Ltd., average particle size 0.04 μm) was used, and a resin emulsion (resin) was prepared in the same manner as in Example 5 except that the following monomers were used as monomers. Toner particles were produced. The toner thus obtained was evaluated by Method 1 and fixed at 138 ° C.

(Table 14)
(Monomers)
80 parts of styrene 20 parts of butyl acrylate 3 parts of acrylic acid 1 part of trichlorobromomethane (initiator)
23.4 aqueous hydrogen peroxide solution 43.4 parts 2% aqueous ascorbic acid solution 43.4 parts

  Except for producing a resin emulsion (referred to as Resin Emulsion K) using a polyethylene wax emulsion (manufactured by Toho Chemical Co., Ltd., Hitech E103N, average particle size 0.03 μm) as the wax emulsion, the same as in Example 7 Resin emulsion and toner particles were manufactured. The toner thus obtained was evaluated by Method 1 and fixed at 140 ° C.

Implementation as a wax emulsion, except that a resin emulsion (referred to as resin emulsion L) is produced using an emulsion (average particle size 0.43 μm) obtained by emulsifying a mixture of glyceride montanate and behenyl behenate with a nonionic surfactant. In the same manner as in Example 7, a resin emulsion and toner particles were produced. The toner thus obtained was evaluated by Method 1 and fixed at 140 ° C. to 190 ° C.

  The resin emulsions A to L used in the examples are collectively shown in the following table.

  That is, in Example 3, the fixing temperature range was 140 to 190 ° C. or more by encapsulating the wax, whereas in Comparative Example 1, when the same amount of wax was co-aggregated, the fixing temperature range was Was 152 to 190 ° C. or higher and the minimum fixing temperature was high. In the present invention, it has been found that even with the same composition as described above, the fixing temperature varies depending on the presence of the wax. Further, in Comparative Example 2, when a toner containing no wax was synthesized and evaluated with respect to Example 3, the fixing temperature range was 160 to 190 ° C. or higher, the minimum fixing temperature was further increased, and the fixing temperature range was It has become smaller. Thus, it was found that the inclusion of wax in the toner lowers the minimum fixing temperature and widens the fixing temperature range, but the effect is particularly great by encapsulating the wax. Similarly, in the case where the monomer composition of the resin, that is, Tg is different, in Example 4, the fixing temperature range was 148 to 190 ° C. or more by encapsulating the wax, whereas in Comparative Example 3, it was the same. When the amount of the wax was co-agglomerated, the fixing temperature range was 168 to 190 ° C. or higher, and the minimum fixing temperature was increased, and it was confirmed that the fixing temperature varies depending on the presence of the wax even in the same composition. Further, in Comparative Example 4, when a toner containing no wax was synthesized and evaluated with respect to Example 4, the fixing temperature range was 170 to 190 ° C. or higher, the minimum fixing temperature was further increased, and the fixing temperature range was It has become smaller.

A uniform and high-quality image is required when performing a large amount of electrostatic development at high speed, performing electrostatic development continuously for a long period of time, or performing electrostatic development in a high-temperature and high-humidity environment. It is useful as a toner for developing an electrostatic image that can be used in various printing machines and copying machines.

Claims (4)

An electrostatic image developing toner comprising a particle aggregate containing polymer primary particles, wherein the polymer primary particles have a structure substantially including a wax inside. 2. The electrostatic image developing toner according to claim 1, wherein the polymer primary particles are polymer particles obtained by seed polymerization using wax emulsion as seed particles. The electrostatic image developing toner according to claim 2, wherein the wax emulsion has an average particle size of 0.01 μm to 3 μm. The electrostatic image developing toner according to claim 1, wherein the polymer primary particles have an acidic polar group or a basic polar group.