JP6608258B2 - Method for producing toner particles - Google Patents

Description

  The present invention relates to a method for producing toner particles for developing an electrostatic image.

A method of visualizing image information through an electrostatic latent image such as electrophotography is currently used in various fields, and improvement in performance such as high image quality and energy saving is demanded. In the electrophotographic method, an electrostatic latent image is first formed on an electrophotographic photosensitive member by charging and exposure processes. Next, the electrostatic latent image is developed with a developer containing toner in a development process, and a fixed image visualized through a fixing process is obtained.
Among them, the development process is an important process for improving the image quality, and the development of systems and materials that achieve high speed and environmental stability is a technical issue. As an approach from the viewpoint of materials, for example, Patent Document 1 discloses a technique for containing a salicylic acid resin having a specific structure and a specific molecular weight in order to obtain a toner having good charge characteristics that rises to a sufficient charge amount in a short time. It is disclosed.

Although this technique can provide a toner with excellent charging characteristics, it has been found that problems occur when it is manufactured under specific conditions. This is a case where the production is carried out in an aqueous medium under the condition of pH = 3.0 or more. Under these conditions, foaming is likely to occur, and in some cases, the foam overflows from the reaction vessel, making it difficult to produce. In addition, heat build-up is hindered by bubbles accumulated on the liquid surface, and the molecular weight of the resulting polymer fluctuates, stirring shearing is inadequate, and aggregated coarse particles are generated. Easy to invite.
With regard to the defoaming technology, a defoaming agent including a silicone type and a device for breaking bubbles by mechanical means are commercially available.
Patent Document 2 discloses a technique for increasing the ratio of alcohol used as a reaction solvent to decrease the ratio of water, and Patent Document 3 discloses a technique for suppressing foaming by performing a polymerization reaction with a specific stirring power.

Japanese Patent No. 5241939 Japanese Patent No. 4056738 Japanese Patent No. 397976

  Addition of commercially available antifoaming agents such as silicone oil and techniques for chemically suppressing bubbles, such as Patent Document 2, have been effective from the viewpoint of enhancing foam suppression. On the other hand, when the obtained toner is evaluated, an adverse effect on the toner performance is observed, and particularly an adverse effect on the developing property is large. This is presumed to be because the added antifoaming agent could not be removed from the toner surface or the inside, and the charging characteristics were adversely affected. It is difficult to wash away organic additives such as oil with water. In the current electrophotographic process aiming at high image quality, additives remaining without being washed away are not preferable because they cause unintended fluctuations in the charge amount.

A certain effect was seen in the technology for breaking bubbles by commercially available mechanical means and the technology for physically suppressing foaming as in Patent Document 3. However, it has been difficult to suppress when foaming causes such as use of a salicylic acid resin having a specific structure and molecular weight or generation of gas during the reaction. Furthermore, a combination technique of the two has been tried, but it has not been possible to find a condition for achieving both toner performance and foam suppression at a high level.
As described above, with the conventional technology, it is difficult to suppress bubbles while suppressing adverse effects on the toner performance, and it is particularly difficult to suppress the accumulation of bubbles even if a factor that causes foaming to increase is added. It was.

  An object of the present invention is a toner that suppresses bubbles without adversely affecting toner performance even when toner particles containing a salicylic acid-based resin are produced in an aqueous medium under a pH = 3.0 or higher condition It is to provide a method for producing particles. Accordingly, it is an object of the present invention to provide a toner particle manufacturing method for enabling stable production, obtaining toner particles at a high yield, and obtaining toner particles having a stable molecular weight and coarse particle weight.

The present invention
A granulating step of forming particles of a polymerizable monomer composition containing a polymerizable monomer, a colorant and a salicylic acid resin in an aqueous medium, and included in the particles of the polymerizable monomer composition A polymerization step of obtaining toner particles by polymerizing the polymerizable monomer, and a method for producing toner particles,
The granulation step and / or the polymerization step includes
A step of mixing the aqueous medium and a water-soluble polyvalent metal compound, and a pH of the aqueous medium mixed with the water-soluble polyvalent metal compound is 3.0 or more, and the metal constituting the polyvalent metal compound a method for producing toner particles comprising the step of adjusting the one or less acid dissociation constant pK _a of hydrated ions.

  According to the present invention, a toner that suppresses bubbles without adversely affecting toner performance even when toner particles containing a salicylic acid-based resin are produced in an aqueous medium under a pH = 3.0 or higher condition. A method for producing particles can be provided. Thus, stable production is possible, toner particles can be obtained with a high yield, and a method for producing toner particles for obtaining toner particles having a stable molecular weight or coarse particle amount can be provided.

FIG. 3 is a schematic diagram illustrating an example of a toner particle charge amount measuring apparatus. 2 is a flowchart showing a granulation step and a polymerization step in Example 1. 3 is a flowchart showing a granulation step and a polymerization step in Example 2. 6 is a flowchart showing a granulation step and a polymerization step in Example 3.

  In order to solve this problem, the present inventor has studied a foaming mechanism. In order to form bubbles, it is necessary for the liquid film to wrap the gas, which is caused and promoted by various factors in the production of toner particles. For example, the gas is entrained in the liquid by stirring, the gas is generated by a chemical reaction, the dissolved gas in the liquid is reduced in solubility as the liquid temperature increases, and bubbles are formed. In particular, when gas is generated by chemical reaction, or the bubble formation of dissolved gas accompanying the rise in liquid temperature, the bubble diameter is fine, so the problem is remarkable because it forms a dense, whipped cream-like foam that is hard to break Become. On the other hand, the generation of bubbles in such a liquid is a phenomenon observed in a general toner particle manufacturing method, but there are many cases where foaming is not a problem depending on the processing liquid. Therefore, it was thought that the problem could be solved by making the treatment liquid difficult to foam.

As a result of further investigation, when toner particles containing a salicylic acid resin are produced in an aqueous medium, the problem of foaming becomes apparent at pH = 3.0 or more, and conversely, production is carried out at pH = 3.0 or less. Found that foaming was slight. Here, was examined in view of the pH, the acid dissociation constant pK _a of salicylic acid is 2.97, problems were found to substantially match the pH of actualized. From this, the following mechanism was assumed as the foaming mechanism. When the pH is 3.0 or more, the acid dissociation of the salicylic acid portion of the salicylic acid resin proceeds, so that the hydrophilicity increases. On the other hand, the other sites are hydrophobic because they are mainly carbon chains. That is, the salicylic acid-based resin has an amphiphilic property by mixing a hydrophilic part and a hydrophobic part. Since the substance having amphiphilic properties stabilizes the liquid film constituting the foam, as represented by household detergents, it can cause foaming.

According to the above estimation, in order to solve the problem, it was considered that the problem could be solved by reducing the amphiphilicity of the salicylic acid-based resin even when the pH was 3.0 or more. That is, it is possible to reduce the amphiphilicity by increasing the hydrophilicity of the hydrophobic site or by increasing the hydrophobicity of the hydrophilic site.
As a means for improving the hydrophilicity of the hydrophobic portion, it is conceivable to oxidize the carbon chain using a strong oxidizing agent. However, it is difficult to return to the original structure, and there is a concern that the adsorbed moisture of the obtained toner particles in a high-temperature and high-humidity environment becomes a problem without returning the structure.

  On the other hand, as a means for improving the hydrophobicity of the hydrophilic portion, it is conceivable to coordinate a polyvalent metal to make a structure like a metal soap. Since the acid-dissociated salicylic acid has a lone pair, it was considered that metal ions can be coordinated under appropriate conditions. Furthermore, after the process where foaming becomes a problem, the metal was released by returning to pH = 3.0 or lower to return to the original salicylic acid structure, so that it was possible to return to the original structure relatively easily. .

As a result of investigation based on the above idea, the present inventor has found that the problem can be solved by mixing an aqueous medium and a water-soluble polyvalent metal compound. However, in the present invention, pH of the aqueous medium of a mixture of polyvalent metal compound is required to be less acid dissociation constant pK _a hydrated ion of the metal constituting the polyvalent metal compound. The study of the present inventors, when the pH of the aqueous medium is greater than _the pK _a of the hydration ions polyvalent metal was confirmed that the effect of the foam is weakened. This is a pH range of greater than pK _a hydrated metal ions is estimated that for a large number of metal can not be coordinated to the salicylic acid to form a hydroxide.

That is, in the present invention, not only the polyvalent metal compound is mixed, but also the pH of the aqueous medium mixed with the polyvalent metal compound is 3.0 or more, and the hydrated ions of the metal constituting the polyvalent metal compound It is necessary to include a step of adjusting to _a pKa of or less. Under the above conditions, it is considered that coordination is possible because salicylic acid and metal exist in an ionized state. The pKa of _a typical metal hydrated ion can include the following. Ca ²⁺ : 12.7, Mg ²⁺ : 11.4, Mn ²⁺ : 10.6, Fe ²⁺ : 9.5, Zn ²⁺ : 9.0, Cu ²⁺ : 7.3, La ³⁺ : 9.0, Al ³⁺ : 5.0, Fe ³⁺ : 2.2.

The present invention was examined in the suspension polymerization method. The suspension polymerization method includes a granulating step of forming particles of a polymerizable monomer composition containing a polymerizable monomer, a colorant and a salicylic acid resin in an aqueous medium, and the polymerizable monomer composition. And a polymerization step of obtaining toner particles by polymerizing the polymerizable monomer contained in the particles.
The water-soluble polyvalent metal compound can be mixed with an aqueous medium in the granulation process and / or an aqueous medium in the polymerization process, but the foam builds up and adversely affects the fluid state of the liquid surface. It is preferred to mix before.

Here, the polyvalent metal compound to be mixed is not particularly limited as long as it is water-soluble. The term “water-soluble” refers to neutral water at room temperature based on the provisions of the PRTR method (Chemical Substance Management Promotion Act). It is defined as dissolving 1% by mass or more.
The salicylic acid-based resin that can be used in the present invention is not particularly limited as long as it has a salicylic acid moiety in the structure. The resin in the present invention is defined as a polymer having a number average molecular weight (Mn) of 1,500 or more. The main chain structure of the salicylic acid resin is not particularly limited. Examples thereof include vinyl polymers, polyester polymers, polyamide polymers, polyurethane polymers, polyether polymers, and the like. Moreover, the hybrid type polymer which combined these 2 or more types is also mentioned. Among these, a polyester polymer or a vinyl polymer is preferable in consideration of adhesion to the toner particle binder resin.

In the present invention, the salicylic acid resin has a weight average molecular weight of 10,000 or more and 60,000 or less, and the number of moles of salicylic acid moieties contained per gram of the salicylic acid resin is 10 μmol / g or more and 1,500 μmol / g. It is preferable that:
Furthermore, the content of the salicylic acid resin contained in the polymerizable monomer composition is 0.03 parts by mass or more and 20.00 parts by mass or less with respect to 100.00 parts by mass of the polymerizable monomer. It is preferable that
Moreover, it is particularly preferable that the salicylic acid-based resin contains a site represented by the following structural formula (1).

This range is a range in which the effect of the present invention can be easily obtained, and is also a preferable range for obtaining good charging characteristics. This is presumably because the molecular weight and the number of moles of the salicylic acid moiety are structures that are easily balanced and have a balance between the hydrophilic group and the hydrophobic group suitable for expressing the effects of the present invention.
Here, the molecular weight is a weight average molecular weight calculated by gel permeation chromatography (GPC). In order to make a weight average molecular weight into said range, it can control by changing conditions, such as a reagent quantity at the time of manufacturing this salicylic acid-type resin, reaction temperature, and solvent concentration. Moreover, the thing of a desired molecular weight can be obtained by fractionating by GPC.
The method for measuring the number of moles of salicylic acid moieties contained per gram of salicylic acid resin is as follows. First, the salicylic acid resin is titrated by the method described below to determine the acid value and hydroxyl value, and the amount of hydroxyl group that the salicylic acid resin has is determined. calculate. Based on this, the content (mol / g) of salicylic acid in the salicylic acid-based resin is calculated. When the salicylic acid-based resin has a hydroxyl group at a site other than salicylic acid, the hydroxyl value of the compound (for example, a polyester resin) immediately before the addition of the salicylic acid site when the salicylic acid-based resin is prepared is measured in advance. The difference can be calculated. Adjustment of the number of moles of salicylic acid moieties contained per gram of salicylic acid resin can be performed by the mixing ratio of raw materials.

Moreover, the effect of foam suppression can be obtained better by satisfying the relationship of the following formula (2).
C × S ≦ N × M (2)
C: Number of moles of salicylic acid moiety contained per gram of the salicylic acid resin (mol / g)
S: Mass (g) of the salicylic acid-based resin contained in the polymerizable monomer composition
N: Metal ion valence of the polyvalent metal compound M: Number of moles of the polyvalent metal compound mixed with the aqueous medium (mol)

The left side of the above formula represents the number of moles of salicylic acid moieties capable of acid dissociation, and the right side represents the number of coordination of the metal compound. In other words, the fact that this formula appears is that there are more metals capable of coordinating there than the number of hydrophilic groups. By using this condition, the amphiphilicity of the salicylic acid resin can be effectively reduced.
Examples of water-soluble polyvalent metal compounds that can be used in the present invention include metal salts. For example, magnesium, calcium, strontium, barium, iron, aluminum, zirconium, gallium, indium, thallium, germanium, tin, lead, bismuth, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, ruthenium, cobalt, nickel, Inorganic metal salts such as halides such as copper, zinc and silver, hexafluorosilylates, sulfates, acetates, thiosulfates, phosphates, chlorates and nitrates. Also, a metal salt of an organic acid can be used if it is water-soluble.

  Specifically, magnesium chloride, calcium chloride, barium chloride, aluminum chloride, tin chloride, lead chloride, strontium chloride, polyaluminum chloride, magnesium bromide, magnesium iodide, calcium bromide, calcium iodide, strontium bromide, Strontium iodide, strontium acetate, barium bromide, barium iodide, magnesium sulfate, calcium sulfate, aluminum sulfate, potassium sulfate aluminum, magnesium chlorate, magnesium phosphate, magnesium nitrate, calcium nitrate, barium nitrate, aluminum nitrate, aluminum lactate , Zirconium acetylacetonate, calcium acetate, magnesium acetate, zirconyl acetate, zirconyl sulfate, ammonium zirconium carbonate, zirconyl stearate, octyl Zirconyl nitrate, zirconium oxychloride, hydroxy zirconium chloride.

  Among these, it is preferable that the metal constituting the polyvalent metal compound is one or two or more selected from iron, aluminum, copper, zinc, magnesium, and calcium, since a further antifoaming effect can be seen. This is presumably because the metal has a high complex stability constant with salicylic acid. Among these, aluminum, magnesium, and calcium are particularly preferable because they have a large ionization tendency and are easily ionized.

However, when the aqueous medium contains hydroxyapatite and the metal constituting the polyvalent metal compound is calcium, attention should be paid to the amount of calcium added. The chemical formula of hydroxyapatite is Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , and the ratio of the number of moles of calcium and phosphorus is 1.67. Therefore, when the number of moles of calcium is M (Ca) and the number of moles of phosphorus is M (P), calcium is easily incorporated into hydroxyapatite crystals under the condition of M (Ca) ≦ 1.67M (P). For this reason, it is difficult to effectively contribute to coordination to salicylate ions. Thus, when using hydroxyapatite and calcium, it is preferable to satisfy | fill the relationship of following formula (3).
C × S ≦ N × (M (Ca) −1.67M (P)) (3)

After the foam suppression is performed by the above means and the process in which foaming is a problem is completed, it is desirable to remove the coordinated metal to return to the original salicylic acid structure, and to remove metal ions from the vicinity of the toner particles. This is preferable from the viewpoint of obtaining performance. As a means for that, it is preferable to provide a filtration step for separating the toner particles and the aqueous medium and to adjust the pH of the aqueous medium to 3.0 or less before the filtration step. By adjusting the pH of the aqueous medium to 3.0 or less, which is the pK _a of salicylic acid, the coordinated metal is removed to return to the original salicylic acid structure, and the metal is present in an ionic state in the aqueous medium. Then, filtration is performed to remove metal ions from the vicinity of the toner particles together with the aqueous medium. More preferably, the pH is adjusted to 1.5 or lower.

  The binder resin used in the toner of the present invention is not particularly limited. For example, the following can be exemplified. Styrene resin, acrylic resin, methacrylic resin, styrene-acrylic resin, styrene-methacrylic resin, polyethylene resin, polyethylene-vinyl acetate resin, vinyl acetate resin, polybutadiene resin, phenol resin, polyurethane resin, polybutyral resin, Polyester resins and hybrid resins in which these resins are arbitrarily combined. Among these, the following are preferably used in terms of toner characteristics. Styrenic resin, acrylic resin, methacrylic resin, styrene-acrylic resin, styrene-methacrylic resin, polyester resin, styrene-acrylic resin, or hybrid resin in which styrene-methacrylic resin and polyester resin are combined.

  As the polyester resin, a polyester resin that is usually produced using a polyhydric alcohol and a carboxylic acid, a carboxylic acid anhydride, or a carboxylic acid ester as raw material monomers can be used. Specifically, the same polyhydric alcohol component and polyvalent carboxylic acid component as the above-described polyester resin can be used. Among these, polyester resins obtained by condensation polymerization of the following components are particularly preferable. The diol component is a bisphenol derivative. As the acid component, a carboxylic acid composed of a divalent or higher carboxylic acid or an acid anhydride thereof; a lower alkyl ester such as fumaric acid, maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid component.

The toner of the present invention can also be used as a magnetic toner. In this case, the following magnetic materials are used. Iron oxide including magnetite, maghemite, ferrite, or other metal oxides; metals such as Fe, Co, Ni, or these metals and Al, Co, Cu, Pb, Mg, Ni, Sn, Alloys with metals such as Zn, Sb, Ca, Mn, Se, Ti, and mixtures thereof. Iron trioxide (Fe ₃ O ₄ ), iron trioxide (γ-Fe ₂ O ₃ ), iron oxide zinc (ZnFe ₂ O ₄ ), copper iron oxide (CuFe ₂ O ₄ ), iron oxide neodymium (NdFe ₂ O) ₃ ), iron barium oxide (BaFe ₁₂ O ₁₉ ), iron magnesium oxide (MgFe ₂ O ₄ ), iron manganese oxide (MnFe ₂ O ₄ ). The magnetic materials described above are used alone or in combination of two or more. A particularly suitable magnetic material is a fine powder of triiron tetroxide or γ-iron sesquioxide.

These magnetic materials preferably have a weight average particle diameter of 0.1 μm to 2 μm, and more preferably 0.1 μm to 0.3 μm. The magnetic characteristics when 795.8 kA / m (10 k Oersted) is applied are such that the coercive force (Hc) is 1.6 kA / m to 12 kA / m (20 Oersted to 150 Oersted), and the saturation magnetization (σs) is 5 Am ² / kg to 200 Am ² / kg. Preferably they are 50 Am < ² > / kg or more and 100 Am < ² > / kg or less. Residual magnetization (.sigma.r) is, ^2Am 2 / kg or more 20 Am ² / kg or less being preferred. The magnetic material is used in an amount of 10.0 parts by mass or more and 200 parts by mass or less, preferably 20.0 parts by mass or more and 150 parts by mass or less based on 100 parts by mass of the binder resin.

On the other hand, as a colorant for use as a non-magnetic toner, a known colorant such as various conventionally known dyes and pigments can be used.
As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, the following colorants are particularly preferable.
C. I. Pigment Red 2, 3, 5-7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254, C.I. I. Pigment Bio Red 19.

  As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 are particularly preferably used.

As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complex methine compounds, and allylamide compounds are used as pigments. Specifically, the following colorants are preferable.
C. I. Pigment Yellow 3, 7, 10, 12 to 15, 17, 23, 24, 60, 62, 74, 75, 83, 93 to 95, 99, 100, 101, 104, 108 to 111, 117, 123, 128, 129,138,139,147,148,150,166,168-177,179,180,181,183,185,191: 1,191,192,193,199.
Examples of the dye system include C.I. I. Solvent Yellow 33, 56, 79, 82, 93, 112, 162, 163, C.I. I. Disperse Yellow 42, 64, 201, 211 can be mentioned.

As the black colorant, carbon black, aniline black, acetylene black, titanium black, and those which are toned in black using the yellow / magenta / cyan colorant shown above can be used.
These colorants can be used alone or in the form of a mixture or a solid solution. The colorant is preferably added in an amount of 0.5 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

The toner of the present invention may contain a release agent. Examples of the release agent include the following.
Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax and paraffin wax; oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax; block copolymers of aliphatic hydrocarbon waxes; Waxes based on fatty acid esters such as carnauba wax, sazol wax, and montanic acid ester wax; and fatty acid esters such as deoxidized carnauba wax partially or wholly deoxidized; fatty acids such as behenic acid monoglyceride A partially esterified product of a monohydric alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenating vegetable oils and fats.

  As for the molecular weight distribution of the release agent, the main peak is preferably in the region of molecular weight of 400 or more and 2,400 or less, and more preferably in the region of 430 or more and 2,000 or less. Thereby, preferable thermal characteristics can be imparted to the toner. The addition amount of the release agent is preferably 2.50 parts by mass or more and 40.0 parts by mass or less, and 3.00 parts by mass or more and 15.0 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferably.

In the toner of the present invention, the charge amount of the toner can be controlled to a desired value by using a charge control agent or a charge control resin mixed (internal addition) or mixed (external addition) with the toner particles.
Examples of the positive charge control agent for toner include the following.
Denatured products of nigrosine and its fatty acids, etc .; onium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonic acid, quaternary ammonium salts such as tetrabutylammonium tetrafluoroborate, and analogs thereof such as phosphonium salts And these lake pigments, triphenylmethane dyes and these lake pigments, metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyltin borate Such diorganotin borates; these alone or in combination of two or more. Among these, charge control agents such as nigrosine, quaternary ammonium salts, and triphenylmethane dyes are particularly preferably used.

  As the negative charge control agent of the toner, an organic metal complex and a chelate compound are effective, and there are a monoazo metal complex, an acetylacetone metal complex, an aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid type metal complex. Others include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenols.

  Here, a form for carrying out the present invention will be described with a representative example. The production method of the toner particles of the present invention was examined in the suspension polymerization method. In the suspension polymerization method, first, a polymerizable monomer for synthesizing a binder resin, a colorant, and a salicylic acid resin are uniformly dissolved or dispersed using a dispersing machine such as a ball mill or an ultrasonic dispersing machine. A polymerizable monomer composition is prepared (preparing step of polymerizable monomer composition). At this time, a polyfunctional monomer, a chain transfer agent, a wax as a release agent, a charge control agent, a plasticizer, and the like can be added as necessary.

  Preferred examples of the polymerizable monomer in the suspension polymerization method include the following vinyl polymerizable monomers. Styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, p- Styrene derivatives such as n-hexyl styrene, pn-octyl, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene; methyl acrylate, ethyl Acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl Acrylic polymerizable monomers such as acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, n- Propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethylphos Fate ethyl methacrylate, dibutyl phosphate ethyl Methacrylic polymerizable monomers such as acrylate; methylene aliphatic monocarboxylic acid esters; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether, vinyl Vinyl ethers such as ethyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

Next, the polymerizable monomer composition is put into an aqueous medium prepared in advance, and droplets made of the polymerizable monomer composition are desired using a stirrer or a disperser having high shearing force. To the size of the toner particles (granulation step).
In the granulation step, high shear is applied to the mixture of the polymerizable monomer composition and the aqueous medium, so that bubbles are easily generated in the treatment liquid due to entrainment of the gas phase portion and cavitation. Bubbles generated in the liquid eventually float and the problem of foaming is minor when the pH of the aqueous medium is less than 3.0, but there is a problem when the pH of the aqueous medium is 3.0 or more. I found out that it will become apparent. As described above, since this is a pH that matches the acid dissociation constant of salicylic acid, it is thought to be due to the expression of amphiphilicity by the dissociation of salicylic acid. By adopting the configuration of the present invention, it is possible to reduce the problem of foaming even when pH = 3.0 or more.

  The aqueous medium in the granulation step preferably contains a dispersion stabilizer in order to control the particle size of the toner particles, sharpen the particle size distribution, and suppress coalescence of the toner particles in the production process. Dispersion stabilizers are generally roughly classified into polymers that develop a repulsive force due to steric hindrance and poorly water-soluble inorganic compounds that achieve dispersion stabilization with an electrostatic repulsive force. The fine particles of the hardly water-soluble inorganic compound are preferably used because they are dissolved by an acid or an alkali and can be easily removed by washing with an acid or an alkali after polymerization.

As the dispersion stabilizer for the hardly water-soluble inorganic compound, those containing any of magnesium, calcium, barium, zinc, aluminum and phosphorus are preferably used. More preferably, any of magnesium, calcium, aluminum, and phosphorus is desired. Specific examples include the following.
Magnesium phosphate, tricalcium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, hydroxyapatide.

  An organic compound such as polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, or starch may be used in combination with the dispersion stabilizer. These dispersion stabilizers are preferably used in an amount of 0.01 to 2.00 parts by mass with respect to 100 parts by mass of the polymerizable monomer. Furthermore, you may use together 0.001 to 0.1 mass% surfactant for refinement | miniaturization of these dispersion stabilizers. Specifically, commercially available nonionic, anionic and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and calcium oleate are preferably used.

After the granulation step or while performing the granulation step, the polymerization is generally performed at a temperature of 50 ° C. or higher and 90 ° C. or lower to obtain a toner particle dispersion (polymerization step).
In the polymerization step, since the temperature of the treatment liquid greatly affects the fixing performance of the toner particles, the stirring operation is generally performed so that the temperature distribution in the container is uniform. When adding a polymerization initiator, it can carry out at arbitrary time and required time. In addition, the temperature may be raised in the latter half of the polymerization reaction for the purpose of obtaining a desired molecular weight distribution, and in order to remove unreacted polymerizable monomers and by-products from the system, the latter half of the reaction, or the completion of the reaction. Later, part of the aqueous medium may be distilled off by distillation. The distillation operation can be performed under normal pressure or reduced pressure.

As the polymerization initiator used in the suspension polymerization method, an oil-soluble initiator is generally used. For example, the following are mentioned.
2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4 -Azo compounds such as methoxy-2,4-dimethylvaleronitrile; acetylcyclohexylsulfonyl peroxide, diisopropylperoxycarbonate, decanonyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, acetyl peroxide, tert- Butylperoxy-2-ethylhexanoate, benzoyl peroxide, tert-butylperoxyisobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, tert- Peroxide-based initiators such as butyl hydroperoxide, di-tert-butyl peroxide, tert-butyl peroxypivalate, cumene hydroperoxide.

As the polymerization initiator, a water-soluble initiator may be used in combination as necessary, and the following may be mentioned.
Ammonium persulfate, potassium persulfate, 2,2'-azobis (N, N'-dimethyleneisobutyroamidine) hydrochloride, 2,2'-azobis (2-aminodinopropane) hydrochloride, azobis (isobutylamidine) Hydrochloride, sodium 2,2′-azobisisobutyronitrile sulfonate, ferrous sulfate or hydrogen peroxide.

  These polymerization initiators can be used alone or in combination, and a chain transfer agent, a polymerization inhibitor and the like can be further added and used to control the degree of polymerization of the polymerizable monomer. When a polymerization initiator is used, there is a substance that generates gas along with its decomposition, and bubbles may be generated in the liquid. In addition, in the polymerization process, bubbles may also be generated in the liquid by cavitation by stirring, entrainment of the gas phase part, bubbling of dissolved gas accompanying an increase in liquid temperature, gas generation by reaction, and the like. Bubbles generated in the liquid eventually float and the problem of foaming is minor when the pH of the aqueous medium is less than 3.0, but there is a problem when the pH of the aqueous medium is 3.0 or more. Realize. Even after the polymerization step, by adopting the configuration of the present invention, it is possible to reduce the problem of foaming even when pH = 3.0 or more.

Although this invention has the process of mixing an aqueous medium and a water-soluble polyvalent metal compound, the polyvalent metal compound to mix does not need to be restricted to one type, and considers cost, handling, etc. as two or more types. Also good.
The water-soluble polyvalent metal compound may be mixed in the form of a powder or may be mixed in advance as an aqueous solution. However, in the case of a substance having a large heat of dissolution, an unintended temperature fluctuation is caused. The method of mixing after is preferable. In order to prevent temperature fluctuation of the aqueous medium, it is particularly preferable to mix the material to be mixed after adjusting the temperature in advance.

  The mixing method can be carried out by any method, and it can be added to the aqueous medium in the reaction vessel from the upper part of the vessel, or a water-soluble polyvalent metal compound or an aqueous solution thereof is awaited in advance in the reaction vessel. In this state, an aqueous medium is added and mixed. When adding a water-soluble polyvalent metal compound, it can be continuously added from the top of the reaction vessel, or intermittently added as necessary when sprayed from a high place, sprayed in a mist, or immersed in a liquid. For example, a method of adding through a nozzle is also possible.

The invention further, pH of the aqueous medium of 3.0 or more of a mixture of polyvalent metal compound of the water-soluble and multivalent metal compound an acid dissociation constant pK _a below to adjust the hydration ions of the metal constituting The process of carrying out is included. When mixing two or more polyvalent metal compound optionally is not more than the value of the pK _a lowest ones. Even when the polyvalent metal compound is mixed, if the pH of the aqueous medium is within the above range, it is not necessary to adjust the pH of the aqueous medium again from the viewpoint of enhancing the foam suppression property. On the other hand, since the particle size distribution and charging performance of the toner particles obtained may vary depending on the pH of the aqueous medium, the pH of the aqueous medium can be arbitrarily adjusted within the above range as necessary.

  Note that depending on the polyvalent metal compound to be mixed, the pH may gradually change due to hydrolysis or the like. In order to prevent the pH of the aqueous medium from fluctuating greatly, a method of mixing the polyvalent metal compound in an aqueous solution and adjusting the pH to an arbitrary pH in advance and mixing with the aqueous medium is preferable. A commercially available pH meter can be used for pH measurement, for example, “Glass Lining pH Measurement System Glass Sensor pH” (manufactured by Shinko Environmental Solution Co., Ltd.) or the like can be used.

  The pH can be adjusted by adding an acid or a base, but Lewis acid should be avoided because it can coordinate with a metal. Examples of acids preferably used in the present invention include hydrochloric acid, sulfuric acid, nitric acid. And hypochlorous acid. Examples of the base include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like.

In the present invention, the toner particles preferably have a weight average particle size of 3.0 μm or more and 10.0 μm or less from the viewpoint of obtaining a high-definition and high-resolution image. The weight average particle diameter of the toner can be measured by a pore electrical resistance method. For example, it can be measured using “Coulter Counter Multisizer 3” (manufactured by Beckman Coulter, Inc.).
The toner particle dispersion thus obtained is sent to a filtration step for solid-liquid separation of the toner particles and the aqueous medium. Before the filtration step, it is preferable from the viewpoint of obtaining desired charging performance to include a step of adjusting the pH of the aqueous medium to 3.0 or less as described above. As a means for adjusting the pH to 3.0 or less, it can be carried out by adding an arbitrary acid. However, in this pH adjustment, it is easy to capture a polyvalent metal by using a Lewis acid, and further a chelating agent, etc. It is also preferable to use together. Examples of acids that can be used for pH adjustment include acetic acid, citric acid, gluconic acid, and phosphoric acid in addition to the acids already mentioned. Moreover, a general thing can be used as a chelating agent. For example, the following are mentioned.
NTA (Nitrilo Triacetic Acid), PDTA (1,3-Propanediamine Tetraacetic Acid), HIDA (Hydroxyethyl Imino Diacetic Acid), HEDP (Hydroxyethylidene Diphosphonic Acid), NTMP (Nitrilotris (Methylene Phosphonic Acid)), PBTC (Phosphonobutane Tricarboxylic Acid).

  Solid-liquid separation for obtaining toner particles from the obtained toner particle dispersion can be carried out by a general filtration method. Thereafter, in order to remove foreign substances that could not be removed from the toner particle surface, reslurry or washing water is used. It is preferable to perform further washing, such as by overwashing. After sufficient washing, solid-liquid separation is performed again to obtain a toner cake. Thereafter, it is dried by a known drying means, and if necessary, a particle group having a particle diameter outside the predetermined range is separated by classification to obtain toner particles. The separated particles having a particle size outside the predetermined range may be reused to improve the final yield.

The toner obtained by the present invention may be only toner particles obtained by the above-described method, or may be obtained by externally adding other external additives to the toner particles for the purpose of imparting various properties to the toner.
The external additive preferably has a particle size of 1/10 or less of the weight average particle size of the toner particles from the viewpoint of durability when added to the toner. Examples of external additives include metal oxides such as aluminum oxide, nitrides such as silicon nitride, carbides such as silicon carbide, inorganic metal salts such as calcium sulfate, fatty acid metal salts such as zinc stearate, carbon black, silica, and the like. Is used. A toner can be obtained by adding a desired external additive to the toner particles and sufficiently mixing with a mixer such as a super mixer or a Henschel mixer.

  The toner produced according to the present invention can be used in any developer as a one-component or two-component developer. For example, as a one-component developer, in the case of a magnetic toner in which a magnetic substance is contained in toner particles, there is a method of conveying and charging the magnetic toner using a magnet built in the developing sleeve. When non-magnetic toner containing no magnetic material is used, there is a method of using a blade, a fur brush, or the like to forcibly charge by a developing sleeve and transport the toner by adhering the toner onto the sleeve.

On the other hand, when used as a two-component developer, a carrier is used as a developer together with the toner of the present invention. The carrier is composed of single and composite ferrites mainly composed of iron, copper, zinc, nickel, cobalt, manganese, and chromium elements. In general, a method in which carrier core particles are generated in advance by firing and granulating the above-mentioned inorganic oxide and then coating a resin is used. In addition, from the viewpoint of reducing the load on the toner of the carrier, the inorganic oxide and the resin are kneaded and then pulverized and classified to obtain a low density dispersed carrier, or the mixture of the inorganic oxide and the monomer is suspended in an aqueous medium. A method of obtaining a polymerization carrier by suspension polymerization can also be used.
Examples of measurement methods that can be used in the present invention are shown below.

<Toner particle size>
As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method provided with a 100 μm aperture tube is used. For setting of measurement conditions and analysis of measurement data, attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with 25,000 effective measurement channels.

As the electrolytic aqueous solution used for the measurement, a special grade sodium chloride is dissolved in ion-exchanged water so that the concentration becomes 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) is used. it can.
Prior to measurement and analysis, the dedicated software was set as follows.
On the “Change Standard Measurement Method (SOMME)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman -Set the value obtained using Coulter Co., Ltd. By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1,600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.
In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) Put 200 mL of the aqueous electrolytic solution into a 250 mL round bottom beaker made exclusively for Multisizer 3, set it on a sample stand, and stir the stirrer rod counterclockwise at 24 rpm. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) Put 30 mL of the electrolytic aqueous solution into a glass 100 mL flat bottom beaker. 0.3 mL of a diluted solution obtained by diluting “Contaminone N” (trade name) manufactured by Wako Pure Chemical Industries, Ltd. with ion-exchanged water 3 times as a dispersant is added thereto. Contaminone N is a 10% by weight aqueous solution of a neutral detergent for pH7 precision measuring instrument cleaning consisting of a nonionic surfactant, an anionic surfactant and an organic builder.

(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetra 150” (manufactured by Nikki Bios Co., Ltd.) with an electrical output of 120 W is prepared. . Put 3.3 liters of ion-exchanged water in the water tank of the ultrasonic disperser, and add 2 mL of Contaminone N into the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.

(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker (1) installed in the sample stand, the electrolyte aqueous solution (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to 5%. The measurement is performed until the number of measured particles reaches 50,000.

(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) and the number average particle diameter (D1) are calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4). The “average diameter” on the “analysis / number statistics (arithmetic average)” screen when the graph / number% is set in the dedicated software is the number average particle diameter (D1).

<Molecular weight>
Calculated in terms of polystyrene by gel permeation chromatography (GPC). For a polymer having a sulfonic acid group, the column elution rate depends on the amount of the sulfonic acid group, so that an accurate molecular weight and molecular weight distribution are not measured. Therefore, it is necessary to prepare a sample in which sulfonic acid groups are capped in advance. Methyl esterification is preferable for capping, and a commercially available methyl esterifying agent can be used. Specifically, a method of treating with trimethylsilyldiazomethane can be mentioned.

  The molecular weight is measured by GPC as follows. A solution obtained by adding the above resin to THF (tetrahydrofuran) and allowing to stand at room temperature for 24 hours is filtered through a solvent-resistant membrane filter “Mysholy disk” (manufactured by Tosoh Corporation) having a pore diameter of 0.2 μm. And measured under the following conditions. In addition, sample preparation adjusts the quantity of THF so that the density | concentration of resin may be 0.8 mass%. When the resin is difficult to dissolve in THF, a basic solvent such as DMF (Dimethylformamide) can be used.

Apparatus: HLC8120 GPC (detector: RI) (manufactured by Tosoh Corporation)
Column: Seven columns of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK)
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Oven temperature: 40.0 ° C
Sample injection volume: 0.10 mL

In calculating the molecular weight of the sample, a molecular weight calibration curve prepared using a standard polystyrene resin column manufactured by Tosoh Corporation listed below is used.
Standard polystyrene resin column: Trade name “TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2 F-1, A-5000, A-2500, A-1000, A-500 "

<Resin acid value>
The acid value is the number of mg of potassium hydroxide necessary for neutralizing the acid contained in 1 g of the sample. The acid value in the present invention is measured according to JIS K 0070-1992. Specifically, it is measured according to the following procedure.
Titration is performed using a 0.1 mol / L potassium hydroxide ethyl alcohol solution (manufactured by Kishida Chemical Co., Ltd.). The factor of the potassium hydroxide ethyl alcohol solution can be determined using a potentiometric titrator (potential difference titrator AT-510 manufactured by Kyoto Electronics Industry Co., Ltd.). 100 mL of 0.100 mol / L hydrochloric acid is placed in a 250 mL tall beaker, titrated with the potassium hydroxide ethyl alcohol solution, and determined from the amount of the potassium hydroxide ethyl alcohol solution required for neutralization. As the 0.100 mol / L hydrochloric acid, one prepared according to JIS K 8001-1998 is used.

The measurement conditions for the acid value measurement are shown below.
Titration apparatus: potentiometric titration apparatus AT-510 (manufactured by Kyoto Electronics Industry Co., Ltd.)
Electrode: Composite glass electrode double junction type (Kyoto Electronics Industry Co., Ltd.)
Titrator control software: AT-WIN
Titration analysis software: Tview
The titration parameters and control parameters at the time of titration are as follows.
Titration parameters Titration mode: Blank titration Titration style: Total titration Maximum titration: 20 mL
Waiting time before titration: 30 seconds Titration direction: Automatic control parameter end point determination potential: 30 dE
End point determination potential value: 50 dE / dmL
End point detection judgment: Not set Control speed mode: Standard gain: 1
Data collection potential: 4 mV
Data collection titration: 0.1 mL

main exam;
0.100 g of a measurement sample is precisely weighed in a 250 mL tall beaker, and 150 mL of a mixed solution of toluene / ethanol (3: 1) is added and dissolved over 1 hour. Titrate with the potassium hydroxide ethyl alcohol solution using the potentiometric titrator.
Blank test;
Titration is performed in the same manner as described above, except that no sample is used (that is, only a mixed solution of toluene / ethanol (3: 1) is used).

The acid value is calculated by substituting the obtained result into the following formula.
A = [(C−B) × f × 5.611] / S
A: Acid value (mgKOH / g),
B: Addition amount (mL) of potassium hydroxide ethyl alcohol solution for blank test,
C: addition amount (mL) of potassium hydroxide ethyl alcohol solution of this test,
f: Factor of potassium hydroxide solution, S: Sample (g).

<Hydroxyl value of resin>
The hydroxyl value is the number of mg of potassium hydroxide required to neutralize acetic acid bonded to a hydroxyl group when 1 g of a sample is acetylated. The hydroxyl value in the present invention is measured according to JIS K 0070-1992. Specifically, it is measured according to the following procedure.
Add 25.0 g of special grade acetic anhydride to a 100 mL volumetric flask, add pyridine to bring the total volume to 100 mL, and shake well to obtain an acetylating reagent. The obtained acetylating reagent is stored in a brown bottle so as not to come into contact with moisture, carbon dioxide gas and the like.

Titration is performed using a 1.0 mol / L potassium hydroxide ethyl alcohol solution (manufactured by Kishida Chemical Co., Ltd.). The factor of the potassium hydroxide ethyl alcohol solution can be determined using a potentiometric titrator (potentiometric titrator AT-510 manufactured by Kyoto Electronics Co., Ltd.).
100 mL of 1.00 mol / L hydrochloric acid is placed in a 250 mL tall beaker, titrated with the potassium hydroxide solution, and determined from the amount of the potassium hydroxide ethyl alcohol solution required for neutralization. As the 1.00 mol / L hydrochloric acid, one prepared according to JIS K 8001-1998 is used.

The measurement conditions for the hydroxyl value measurement are shown below.
Titration apparatus: potentiometric titration apparatus AT-510 (manufactured by Kyoto Electronics Industry Co., Ltd.)
Electrode: Composite glass electrode double junction type (Kyoto Electronics Industry Co., Ltd.)
Titrator control software: AT-WIN
Titration analysis software: Tview
The titration parameters and control parameters at the time of titration are as follows.
Titration parameters Titration mode: Blank titration Titration mode: Total titration Maximum titration: 80 mL
Waiting time before titration: 30 seconds Titration direction: Automatic control parameter End point determination potential: 30 dE
End point determination potential value: 50 dE / dmL
End point detection judgment: Not set Control speed mode: Standard gain: 1
Data collection potential: 4 mV
Data collection titration: 0.5 mL

2.00 g of the pulverized measurement sample is precisely weighed into a 200 mL round bottom flask, and 5.00 mL of the acetylating reagent is accurately added to this using a whole pipette. At this time, if the sample is difficult to dissolve in the acetylating reagent, a small amount of special grade toluene is added and dissolved.
Place a small funnel on the mouth of the flask and immerse the bottom of the flask in a glycerin bath at a temperature of 97 ° C. and heat. At this time, in order to prevent the temperature of the neck of the flask from rising due to the heat of the bath, it is preferable to cover the base of the neck of the flask with a cardboard having a round hole.

After 1 hour, the flask is removed from the glycerin bath and allowed to cool. After standing to cool, 1.00 mL of water is added from the funnel and shaken to hydrolyze acetic anhydride. The flask is again heated in the glycerin bath for 10 minutes for further complete hydrolysis. After cooling, wash the funnel and flask walls with 5.00 mL of ethyl alcohol.
The obtained sample is transferred to a 250 mL tall beaker, and 100 mL of a mixed solution of toluene / ethanol (3: 1) is added and dissolved over 1 hour. Titrate with the potassium hydroxide ethyl alcohol solution using the potentiometric titrator.
(B) Blank test Titration similar to the above operation is performed except that no sample is used.

(3) Substituting the obtained results into the following formula to calculate the hydroxyl value.
A = [{(BC) × 28.05 × f} / S] + D
A: Hydroxyl value (mgKOH / g),
B: Addition amount (mL) of potassium hydroxide ethyl alcohol solution for blank test,
C: addition amount (mL) of potassium hydroxide ethyl alcohol solution of this test,
f: Factor of potassium hydroxide solution, S: Sample (g),
D: Resin acid value (mgKOH / g).

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these. First, a method for evaluation performed in Examples will be described below.

<Heap accumulation height>
In order to evaluate the degree of foaming, the height at which bubbles were deposited was measured. First, the liquid level position in a state where foaming was not performed was measured. For the measurement, a metal rod was vertically inserted into the reaction vessel from the inspection port of the reaction vessel to reach below the liquid level. At this time, the metal bar was marked so that the height of the inspection port could be seen. Since the portion reaching the liquid level or lower on the metal bar is colored with the colorant, the distance T0 from the inspection port to the liquid level could be obtained by measuring the length from the marking portion to the colored portion.

  Furthermore, in the process where foaming is a problem, the position of the foam was measured. In the process where foaming is a problem, when the metal rod was inserted by the same method as the method for measuring the liquid level, the metal rod was colored according to the height at which bubbles were deposited. By measuring the length of the colored portion and the marking portion, the bubble position T1 could be obtained from the inspection port. The height at which the bubbles were deposited could be obtained from the difference between T0 and T1.

<Evaluation of charge amount>
A two-component developer was prepared as follows. 276 g of the Standard Imaging Society of Japan N-01 and 24 g of evaluation toner particles are put into a 500 cc plastic bottle with a lid, and 1 shaker (YS-LD: manufactured by Yayoi Co., Ltd.) with a speed of 4 reciprocations per second. Shake for a minute. The toner particles and the two-component developer were evaluated as follows.

<Evaluation of charge amount under high temperature and high humidity>
To measure the amount of charge, 30 g of the two-component developer was collected, left in a high temperature and high humidity environment (temperature 30 ° C./relative humidity 85%) for 5 days, and then placed in a 50 mL insulating plastic container, 200 times / The sample was shaken for 3 minutes at a rate of minutes and measured using the apparatus of FIG.

(Measurement method of charge amount)
A two-component developer 0.500 g for measuring the triboelectric charge amount was put in a metal measuring container 2 having a screen 3 having a 500 mesh (aperture 25 μm) at the bottom shown in FIG. The total mass of the measurement container 2 at this time is weighed and is defined as Wl (g). Next, in the suction device 1 (at least a portion in contact with the measurement container 2), the pressure of the vacuum gauge 5 was adjusted to 250 mmAq (2.4517 kPa) by suction from the suction port 7 and adjusting the air volume control valve 6. In this state, the toner was sucked and removed by suction for 2 minutes.
The potential of the electrometer 9 at this time is set to V (volt). The capacity of the capacitor 8 is C (μF). The mass of the entire measurement container after the suction is weighed and is defined as W2 (g). The triboelectric charge amount of the toner is calculated by the following formula.
Frictional charge (mC / kg) = (C × V) / (W1-W2)

<Evaluation of environmental dependency of charge amount>
The toner charging is performed in the same manner as described in the above-described evaluation of the toner charge amount under the high temperature and high humidity environment, except that the stationary environment of the two-component developer is a low temperature and low humidity environment (temperature 10 ° C./relative humidity 15%) The quantity was measured. In the evaluation, the absolute value of the ratio of the charge amount under the low temperature and low humidity environment and the high temperature and high humidity environment (charge amount under the low temperature and low humidity environment / charge amount under the high temperature and high humidity environment) was calculated.

<Evaluation of rising characteristics of charge amount>
30 g of the two-component developer was collected and allowed to stand for 5 days in a high temperature and high humidity environment (temperature 30 ° C./relative humidity 85%), and then placed in a 50 mL insulating plastic container. The sample was shaken for 30 seconds at a rate of 200 times / minute, and the charge amount was measured using the apparatus shown in FIG. The triboelectric charge obtained in the evaluation of the charge amount of the toner in a high temperature and high humidity environment was taken as the saturation charge amount, and the rise (%) was calculated by the following formula.
Rise (%) = {30-second shaking charge amount (mC / kg) / saturation charge amount (mC / kg)} × 100

<Remaining amount of mixed polyvalent metal>
The amount of metal contained in the toner particles is determined by fluorescent X-rays. The measurement of the fluorescent X-ray of each element is in accordance with JIS K 0119-1969, and is specifically as follows.
As a measuring device, a wavelength dispersion type fluorescent X-ray analyzer “Axios” (manufactured by PANalytical) and attached dedicated software “SuperQ ver. 4.0F” (manufactured by PANalytical) for setting measurement conditions and analyzing measurement data ) Was used. Rh was used as the anode of the X-ray tube, the measurement atmosphere was vacuum, the measurement diameter (collimator mask diameter) was 27 mm, and the measurement time was 10 seconds. Moreover, when measuring a light element, it detected with the proportional counter (PC), and when measuring a heavy element, it detected with the scintillation counter (SC).

As a measurement sample, 4 g of toner particles are put in a dedicated aluminum ring for press and flattened, and a tablet molding compressor “BRE-32” (manufactured by Maekawa Test Instruments Co., Ltd.) is used at 20 MPa. The pellets were pressed for 60 seconds and molded into a thickness of 2 mm and a diameter of 39 mm.
The measurement was performed under the above conditions, the element was identified based on the obtained X-ray peak position, and the concentration was calculated from the count rate (unit: cps) which is the number of X-ray photons per unit time.
Using this measurement result and a calibration curve prepared in advance for the metal element to be quantified, the metal element was quantified.

<Evaluation of image performance / Evaluation of image black spot>
If there is a place where stirring is not achieved due to the accumulation of bubbles, coarse particles are generated, and black spots tend to occur. To 100 parts by mass of toner particles, 3 parts by mass of hydrophobic silica having a specific surface area measured by the BET method of 200 m ² / g was externally added to obtain a toner. Using this toner as a one-component developer, evaluation was performed using LBP5800 (manufactured by Canon Inc.).
First, 100 g of the obtained toner was filled in a cartridge, and in a durability test under a low temperature and low humidity environment (temperature 15 ° C./relative humidity 10%), the fixing roller and the image after printing out 10,000 sheets were visually observed. It confirmed and evaluated as shown below.
A: Toner adhesion is not observed on the fixing roller, and black spots are not observed on the image.
B: Although toner adhesion is observed on the fixing roller, no black spots are observed on the image.
C: One or two black spots are seen on the image.
D: Three or more black spots are seen on the image.

[Example 1]
As shown in FIG. 2, in Example 1, the granulation step includes a step of mixing an aqueous medium and a water-soluble polyvalent metal compound and a pH adjustment step.
<Preparation process of polymerizable monomer composition>
The following materials were heated to a temperature of 60 ° C. and dissolved and mixed for 30 minutes to obtain a polymerizable monomer composition.
・ Styrene monomer 29.2kg
・ N-Butyl acrylate 12.5kg
・ Divinylbenzene 0.2kg
・ C. I. Pigment Blue 15: 3 2.7kg
・ Saturated polyester resin 6.3kg
(Polycondensation product of propylene oxide-modified bisphenol A (2 mole adduct) and terephthalic acid (molar ratio 10:12), glass transition temperature Tg = 68 ° C., weight average molecular weight Mw = 10,000, molecular weight distribution Mw / Mn = 5.12)
-Paraffin wax (HNP-5, manufactured by Nippon Seiwa Co., Ltd.) 5.0 kg
-Salicylic acid resin A 4.170kg
(Polystyrene resin containing a salicylic acid moiety of structural formula (1) in the side chain. Table 1A shows the measurement results of the weight average molecular weight and the number of moles of the salicylic acid moiety.)

<Preparation process of aqueous medium>
Ion-exchanged water 122.8 kg, Na ₃ PO ₄ · 12H ₂ O 2.6 kg (6.8 mol) and 10% hydrochloric acid 1.2 kg were added and the diameter was changed using CLEARMIX (M Technique Co., Ltd.). The mixture was heated to 60 ° C. while stirring at 4,500 rpm with a 90 mm rotor. To this, 11.8 kg of 1.0 mol / liter-CaCl ₂ .2H ₂ O aqueous solution was added and stirred for 30 minutes to obtain an aqueous medium containing hydroxyapatite. The pH of the aqueous medium at this time was 5.0.

<Step of mixing aqueous medium and water-soluble polyvalent metal compound>
An aqueous 1.0 mol / liter-AlCl ₃ .6H ₂ O solution was prepared in advance, and 5 liters were adjusted to pH = 4.0 and a temperature of 60 ° C. This was added after preparation of the aqueous medium, and the aqueous medium and AlCl ₃ were mixed.
<PH adjustment step>
The acid dissociation constant of the hydrated ion of aluminum is 5.0. The pH of the aqueous medium mixed with the polyvalent metal compound was adjusted to pH = 4.0 using 10% hydrochloric acid and sodium hydroxide.

<Step of granulating>
The polymerizable monomer composition is charged into an aqueous medium, and stirred at 4,500 rpm for 15 minutes with Claremix at a temperature of 60 ° C. in a nitrogen atmosphere, and particles of the polymerizable monomer composition are added to the aqueous medium. A dispersion in which was formed was prepared.

<Polymerization process>
A dispersion liquid in which particles of the polymerizable monomer composition were formed was put into a reaction vessel kept in a nitrogen atmosphere and stirred. The reaction vessel communicates with the atmosphere through a condenser, and has an inner diameter of 650 mm and R bottom equipped with two baffles and a full zone stirring blade, and the height from the vessel bottom to the inspection port is 1,110 mm. As a polymerization initiator, 5.0 kg of tert-butyl peroxypivalate was added, the temperature was raised to 70 ° C., and a polymerization reaction was carried out for 10 hours. In the polymerization process, bubbles were generated in the liquid as the polymerization initiator was decomposed. While the foam height by foaming increased and then decreased, the foam height was measured according to the method for measuring foam height described above. Table 2 shows the “bubble height of deposition” at the time when the height of deposition was the highest.

<Distillation process>
After completion of the polymerization reaction, saturated water vapor (steam pressure: 205 kPa / temperature: 120 ° C.) was introduced while stirring was continued with a full zone stirring blade. With the introduction of saturated steam, the temperature of the reaction liquid rose and a distillation fraction began to come out. Residual monomers were distilled off by obtaining a predetermined amount of fractions, and cooled to obtain a toner particle dispersion.

<Washing / solid-liquid separation / drying process>
While stirring the obtained toner particle dispersion, 10% hydrochloric acid was added to adjust the pH to 1.5. This was subjected to solid-liquid separation with a pressure filter to obtain a wet cake of toner. This was put into water and stirred to obtain a dispersion again, followed by solid-liquid separation with the above-mentioned filter. Re-dispersion of the toner wet cake in water and solid-liquid separation were repeated 5 times, and finally solid-liquid separation was performed to obtain a toner wet cake.
The resulting toner wet cake was crushed and dried with an air dryer (manufactured by Seishin Corporation: flash jet dryer: pipe diameter 0.1016 m) to obtain toner particles. Drying conditions were hot air blowing temperature 90 ° C., blowing air volume 10 m ³ / min, and toner wet cake feed rate was such that the product outlet temperature of the dryer would be 40 ° C. according to the moisture content of the toner wet cake. Adjusted to speed.

<Evaluation>
Evaluation of the charge amount of the obtained toner particles under the above-described high temperature and high humidity environment, evaluation of the dependency of the toner charge amount on the environment, evaluation of the charge amount rise characteristic, residual amount of mixed polyvalent metal, evaluation of image performance / Evaluation was performed according to the evaluation method of image black spot evaluation. The production conditions are shown in Table 1A, and the evaluation results are shown in Table 2.

[Example 2]
In <Example 1><the step of mixing the aqueous medium and the water-soluble polyvalent metal compound>, 5 liters of 1.0 mol / liter-AlCl ₃ .6H ₂ O aqueous solution was previously prepared at pH = 4.0, temperature 60 The temperature was adjusted to ° C. and kept in the polymerization reaction vessel. Were mixed aqueous medium and AlCl ₃ was charged dispersion here in the polymerizable monomer composition having been subjected to the granulation process. Thereafter, <pH adjustment step> was performed. Otherwise, toner particles were prepared in the same manner as in Example 1. The production conditions are shown in Table 1A, and the evaluation results are shown in Table 2.
As shown in FIG. 3, in Example 2, the polymerization step includes a step of mixing an aqueous medium and a water-soluble polyvalent metal compound and a pH adjustment step.

Example 3
The 1.0 mol / liter-AlCl ₃ .6H ₂ O aqueous solution added in <the step of mixing the aqueous medium and the water-soluble polyvalent metal compound> in Example 1 was 2.5 liters.
Further, 2.5 liters of a 1.0 mol / liter-AlCl ₃ .6H ₂ O aqueous solution was adjusted in advance to pH = 4.0 and a temperature of 60 ° C. and kept in a polymerization reaction vessel. Were mixed aqueous medium and AlCl ₃ was charged dispersion here in the polymerizable monomer composition having been subjected to the granulation process. Thereafter, <pH adjustment step> was performed. Otherwise, toner particles were prepared in the same manner as in Example 1. The production conditions are shown in Table 1A, and the evaluation results are shown in Table 2.
As shown in FIG. 4, in Example 3, both the granulation step and the polymerization step include a step of mixing an aqueous medium and a water-soluble polyvalent metal compound and a pH adjustment step.

Example 4
In <pH adjustment step>, the pH was adjusted to 3.0. Otherwise, toner particles were prepared in the same manner as in Example 1. The production conditions are shown in Table 1A, and the evaluation results are shown in Table 2.
Example 5
In <pH adjustment step>, the pH was adjusted to 5.0. Otherwise, toner particles were prepared in the same manner as in Example 1. The production conditions are shown in Table 1A, and the evaluation results are shown in Table 2.
[Examples 6 to 17]
Toner particles were prepared in the same manner as in Example 1 except that the physical properties of the salicylic acid resin A were changed as shown in Tables 1A to 1B. The production conditions are shown in Tables 1A to 1B, and the evaluation results are shown in Table 2.

Example 18
Toner particles were prepared in the same manner as in Example 1 except that salicylic acid resin B was used instead of salicylic acid resin A. Manufacturing conditions are shown in Table 1B, and evaluation results are shown in Table 2.
The salicylic acid resin B is a polystyrene resin containing a salicylic acid moiety of the structural formula (4) in the side chain. The measurement results of the molecular weight and the number of moles of the salicylic acid moiety are shown in Table 1B.

[Examples 19 to 28]
Toner particles were prepared in the same manner as in Example 1 except that the type and amount of the water-soluble polyvalent metal compound were changed as shown in Table 1C. The production conditions are shown in Table 1C, and the evaluation results are shown in Table 2.
[Examples 29 to 30]
Toner particles were prepared in the same manner as in Example 1 except that the pH after pH adjustment in the filtration step was changed as shown in Table 1C. The production conditions are shown in Table 1C, and the evaluation results are shown in Table 2.

[Comparative Example 1]
The step of mixing the aqueous medium and the water-soluble polyvalent metal compound in Example 1 was not performed. Otherwise, toner particles were prepared in the same manner as in Example 1. The manufacturing conditions are shown in Table 1D, and the evaluation results are shown in Table 2.
[Comparative Example 2]
In <the step of mixing the aqueous medium and the water-soluble polyvalent metal compound> in Example 1, sodium chloride, which is a water-soluble but non-polyvalent metal compound, was used. Otherwise, toner particles were prepared in the same manner as in Example 1. The manufacturing conditions are shown in Table 1D, and the evaluation results are shown in Table 2.

[Comparative Example 3]
In the step of mixing the aqueous medium and the water-soluble polyvalent metal compound in Example 1, aluminum oxide of a metal compound that is not water-soluble was used. Otherwise, toner particles were prepared in the same manner as in Example 1. The manufacturing conditions are shown in Table 1D, and the evaluation results are shown in Table 2.
[Comparative Example 4]
Toner particles were produced in the same manner as in Example 1 except that the production conditions were changed as shown in Table 1D. The evaluation results are shown in Table 2.

  As is clear from Table 2, the toner particle production method “Examples 1 to 30” of the present invention has a pH value in which the toner particles containing the salicylic acid resin are in an aqueous medium as compared with “Comparative Examples 1 to 4”. = Even if the production was performed under the condition of 3.0 or more, the accumulation of bubbles could be reduced. The toner particles obtained by the method for producing toner particles of the present invention were also excellent in charging performance, the amount of residual metal in the toner, and image characteristics.

DESCRIPTION OF SYMBOLS 1 Suction machine 2 Measuring container 3 Screen 4 Lid 5 Vacuum gauge 6 Air volume control valve 7 Suction port 8 Condenser 9 Electrometer

Claims (7)

A granulating step of forming particles of a polymerizable monomer composition containing a polymerizable monomer, a colorant and a salicylic acid-based resin in an aqueous medium, and included in the particles of the polymerizable monomer composition In a method for producing toner particles, comprising a polymerization step of obtaining toner particles by polymerizing the polymerizable monomer,
The granulation step and / or the polymerization step includes
A step of mixing the aqueous medium and a water-soluble polyvalent metal compound, and a pH of the aqueous medium mixed with the water-soluble polyvalent metal compound is 3.0 or more, and the metal constituting the polyvalent metal compound method for producing toner particles comprising the step of adjusting the one or less acid dissociation constant pK _a of hydrated ions. The salicylic acid resin has a weight average molecular weight of 10,000 or more and 60,000 or less, and the number of moles of salicylic acid moieties contained per gram of the salicylic acid resin is 10 (μmol / g) or more and 1,500 (μmol / mol). g)
The content of the salicylic acid resin contained in the polymerizable monomer composition is 0.03 parts by mass or more and 20.00 parts by mass or less with respect to 100.00 parts by mass of the polymerizable monomer. The method for producing toner particles according to claim 1. The method for producing toner particles according to claim 1, wherein the salicylic acid-based resin contains a site represented by the following structural formula (1).

The number of moles of salicylic acid moieties contained per gram of the salicylic acid resin is C (mol / g), the mass of the salicylic acid resin contained in the polymerizable monomer composition is S (g), The metal ion valence of the metal compound is N (valence), and the number of moles of the polyvalent metal compound mixed with the aqueous medium is M (mol). 4. The method for producing toner particles according to any one of 3 above.
C × S ≦ N × M (2)   The metal which comprises this polyvalent metal compound is 1 type, or 2 or more types selected from the group which consists of iron, aluminum, copper, zinc, magnesium, and calcium, The any one of Claims 1-4 A method for producing toner particles. The aqueous medium contains hydroxyapatite;
The metal constituting the polyvalent metal compound is calcium;
Claim 1 that satisfies the relationship of the following formula (3), where M (Ca) is the molar number of calcium contained in the aqueous medium in which the polyvalent metal compound is dissolved, and M (P) is the molar number of phosphorus. 6. The method for producing toner particles according to any one of 5 above.
C × S ≦ N × (M (Ca) −1.67M (P)) (3)   7. The method according to claim 1, further comprising a filtration step of separating the toner particles and the aqueous medium, and the step of adjusting the pH of the aqueous medium to 3.0 or less before the filtration step. The method for producing toner particles according to Item.

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