JP6571508B2 - Method for producing toner for electrophotography - Google Patents

Description

  The present invention relates to an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a method for producing the same.

  From the viewpoint of speeding up printing apparatuses and saving energy, toners using a composite resin of a polycondensation resin and a styrene resin that are superior in low-temperature fixing property and storage stability have been developed.

  For example, Patent Document 1 discloses a method for producing toner particles containing a binder resin containing a styrene acrylic resin as a main component, a colorant, and a crystalline resin, which is obtained by suspension polymerization or dissolution suspension. After the particles are produced, the method includes a step of heating and holding the resin particles in an aqueous medium at a temperature not lower than the midpoint glass transition temperature of the binder resin and not higher than the melting start temperature of the crystalline resin for not less than 0.5 hours. A featured toner particle manufacturing method is disclosed.

JP2013-80112A

  However, in recent years, from the viewpoint of further increasing the speed and energy saving of a printing apparatus, there is a demand for an electrophotographic toner that is excellent in low-temperature fixability, color development of printed matter, and suppression of toner scattering while maintaining storage stability. .

  Accordingly, the present invention relates to an electrophotographic toner excellent in low temperature fixability, toner color development and suppression of scattering while maintaining storage stability, and a method for producing the same.

The present invention
[1] Step 1: Polyester resin raw material monomer containing an alcohol component and a carboxylic acid component and a (meth) acrylic acid compound are polycondensed at 180 ° C. or higher and 250 ° C. or lower for 1 hour or longer to give an acid value of 5.0. Step of obtaining a polyester resin of mgKOH / g or less, and Step 2: A polymerizable monomer composition in which at least the polyester resin, the colorant, and the release agent obtained in Step 1 are dissolved in the raw material monomer of the styrene acrylic resin A process for producing a toner for electrophotography, comprising a step of suspension polymerization in an aqueous medium, and [2] Step 1: a raw material monomer of a polyester resin containing an alcohol component and a carboxylic acid component, and a (meth) acrylic acid compound And a step of obtaining a polyester resin having an acid value of 5.0 mgKOH / g or less and a step 2: a raw material monomer for styrene acrylic resin The present invention relates to an electrophotographic toner obtained by a method comprising a step of suspension polymerization of a polymerizable monomer composition in which a polyester resin, a colorant and a release agent obtained in Step 1 are dissolved in an aqueous medium. .

  According to the method of the present invention, it is possible to obtain an electrophotographic toner that is excellent in low-temperature fixability, toner coloring property and scattering suppression while maintaining storage stability.

The present invention
Step 1: A step of obtaining a low acid value polyester resin by polycondensing a raw material monomer of a polyester resin containing an alcohol component and a carboxylic acid component and a (meth) acrylic acid compound at a predetermined temperature for a predetermined time; and Step 2: A method comprising the step of suspension polymerization of a polymerizable monomer composition obtained by dissolving the polyester resin, colorant, and release agent obtained in Step 1 in a raw material monomer of a styrene acrylic resin in an aqueous medium. This is a method for producing an electrophotographic toner.
In addition, the present invention is an electrophotographic toner obtained by a method including Step 1 and Step 2.

The reason why the toner obtained by the method of the present invention is excellent in low-temperature fixability, toner color development, and toner scattering suppression is not clear, but is presumed as follows.
Normally, polyester resin and styrene acrylic resin are incompatible, and it is difficult to finely disperse polyester resin in styrene acrylic resin, but the raw material monomer of polyester resin and styrene acrylic resin having an unsaturated bond at the terminal is In order to be compatible, a polyester resin having an unsaturated bond at the terminal is prepared using a (meth) acrylic acid compound in advance (Step 1), and this polyester resin is dissolved in a raw material monomer of a styrene acrylic resin. By polymerizing the raw material monomer (Step 2), the polyester resin and the styrene acrylic resin are bonded through an unsaturated bond, and the resin in which the polyester resin and the styrene acrylic resin are polymerized is uniformly dispersed in the styrene acrylic resin. Toner is obtained. Thereby, at the time of fixing, the styrene acrylic resin is dissolved together with the polyester resin having excellent fixability, and the low-temperature fixability is improved.
In addition, since the colorant has good compatibility with a resin obtained by polymerizing a polyester resin and a styrene acrylic resin, the colorant is uniformly dispersed together with the polyester resin, and the color developability is improved.
Furthermore, when the release agent is dissolved in a styrene acrylic resin together with a polyester resin to form toner particles, the release agent tends to migrate to the toner surface. If the release agent is present on the toner surface, it easily breaks at the interface between the release agent and the resin, causing toner scattering. However, in the present invention, since the polyester resin and the styrene acrylic resin are bonded through an unsaturated bond, the polyester resin and the styrene acrylic resin are fixed, the migration of the release agent to the toner surface is inhibited, and the toner scattering is prevented. It is suppressed.

  In step 1, a raw material monomer of a polyester resin containing an alcohol component and a carboxylic acid component and a (meth) acrylic acid compound are polycondensed at 180 ° C. or higher and 250 ° C. or lower for 1 hour or longer to obtain an acid value of 5.0 mgKOH / This is a step of obtaining a polyester resin of g or less.

  The raw material monomer of the polyester resin is not particularly limited, and examples thereof include an alcohol component containing a divalent or higher alcohol and a carboxylic acid component containing a divalent or higher carboxylic acid compound.

  Examples of the divalent or higher alcohol include aliphatic diols, alicyclic diols, aromatic diols, and the like, and from the viewpoint of low-temperature fixability and storage stability, an aliphatic diol is preferably included.

  Aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 3,4-hexanediol, 2,4-hexanediol, 2 , 5-hexanediol, 1,4-butenediol, neopentyl glycol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecane Diol, 1,12-dodecanediol, 1,14-tetradecanediol, etc. Are, alpha, .omega. aliphatic diols are preferred. It is preferable to use one or more of these.

  The carbon number of the aliphatic diol is preferably 6 or more, more preferably 9 or more, from the viewpoint of storage stability and toner scattering suppression, and preferably 14 or less from the viewpoint of low-temperature fixability and toner scattering suppression. More preferably, it is 12 or less.

The content of the aliphatic diol in the alcohol component contained in the raw material monomer of the polyester resin is preferably 75 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably 95 mol%. More preferably, it is 100 mol%.
The content of the aliphatic diol having 6 or more carbon atoms in the alcohol component contained in the raw material monomer of the polyester resin is preferably 70 mol% or more, more preferably from the viewpoint of excellent compatibility between low-temperature fixability and heat-resistant storage stability. It is 80 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more, and further preferably 100 mol%.

  Examples of the aromatic diol include an alkylene oxide adduct of bisphenol A. The propylene oxide adduct of bisphenol A includes the formula (I):

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y are the average number of moles of alkylene oxide added, each being a positive number, The sum value is 1 or more, preferably 1.5 or more, 16 or less, preferably 8 or less, more preferably 4 or less)
The compound represented by these is preferable.

  The content of the aromatic diol in the alcohol component contained in the raw material monomer of the polyester resin is preferably at least 70 mol%, more preferably at least 80 mol%, even more preferably from the viewpoint of achieving both low temperature fixability and storage stability. Is 90 mol% or more.

  On the other hand, the divalent or higher carboxylic acid compound is an aromatic dicarboxylic acid compound such as phthalic acid, isophthalic acid or terephthalic acid; aliphatic dicarboxylic acid compound; , 4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, trivalent or higher carboxylic acid compounds such as pyromellitic acid, etc., from the viewpoint of low-temperature fixability and storage stability It is preferable that an aliphatic dicarboxylic acid compound is included.

  Examples of aliphatic dicarboxylic acid compounds include succinic acid (carbon number: 4), fumaric acid (carbon number: 4), glutaric acid (carbon number: 5), adipic acid (carbon number: 6), suberic acid ( Carbon number: 8), azelaic acid (carbon number: 9), sebacic acid (carbon number: 10), dodecanedioic acid (carbon number: 12), tetradecanedioic acid (carbon number: 14), alkyl group in the side chain or Examples thereof include succinic acid having an alkenyl group, anhydrides of these acids, alkyl esters having 1 to 3 carbon atoms thereof, and the like. It is preferable to use one or more of these.

  The chain hydrocarbon group in the aliphatic dicarboxylic acid-based compound may be linear or branched, but is preferably a saturated hydrocarbon group. The number of carbon atoms of the aliphatic dicarboxylic acid compound is preferably 8 or more, more preferably 10 or more, from the viewpoint of fluidity, and preferably 14 or less, more preferably from the viewpoint of low-temperature fixability and toner scattering suppression. Is 12 or less. In the present invention, the carboxylic acid compound includes not only a free acid but also an anhydride that decomposes during the reaction to produce an acid, or an alkyl ester having 1 to 3 carbon atoms. However, the carbon number of the alkyl group in the alkyl ester portion is not included in the carbon number of the aliphatic dicarboxylic acid compound.

The content of the aliphatic dicarboxylic acid compound in the carboxylic acid component contained in the raw material monomer of the polyester resin is preferably 75 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and even more preferably. Is 95 mol% or more, more preferably 100 mol%.
The content of the aliphatic dicarboxylic acid compound having 6 or more carbon atoms in the carboxylic acid component contained in the raw material monomer of the polyester resin is preferably 70 mol% or more, more preferably from the viewpoint of excellent heat-resistant storage stability of the toner. It is 80 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more, and further preferably 100 mol%.

  A monovalent alcohol may be appropriately contained in the alcohol component, and a monovalent carboxylic acid compound may be appropriately contained in the carboxylic acid component from the viewpoint of adjusting the molecular weight.

  Moreover, in the raw material monomer of the polyester resin subjected to Step 1, the equivalent ratio (COOH group / OH group) of the carboxylic acid component and the alcohol component is preferably close to the equivalent, preferably 0.7, from the viewpoint of storage stability. Above, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

  Examples of the (meth) acrylic acid-based compound include one or more selected from the group consisting of (meth) acrylic acid and (meth) acrylic acid alkyl esters. From the viewpoint of suppressing scattering, (meth) acrylic acid alkyl ester is more preferable. It is considered that the alcohol component of the alkyl group of the alkyl ester reacts with the carboxylic acid terminal of the polyester resin by a transesterification reaction to suppress the cross-linking reaction between the polycondensates. In the present specification, “(meth) acrylic acid” means acrylic acid and / or methacrylic acid.

  The number of carbon atoms of the (meth) acrylic acid alkyl ester is preferably 4 or more, more preferably from the viewpoint of high low-temperature fixability and high toner coloration and scattering suppression effect because it is highly reactive and hardly volatilizes out of the system. Is 5 or more, more preferably 6 or more, and from the viewpoint of color developability, preferably 22 or less, more preferably 18 or less, more preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, Preferably it is 6 or less. In addition, the number of carbon atoms of the alkyl group of the (meth) acrylic acid alkyl ester is preferably 1 or more, more preferably 2 or more, and still more preferably 4 from the viewpoint of low-temperature fixability and high toner color development and scattering suppression effects. From the viewpoint of color developability, it is preferably 18 or less, more preferably 14 or less, still more preferably 12 or less, still more preferably 8 or less, still more preferably 6 or less, and even more preferably 2 or less.

  The amount of the (meth) acrylic acid compound used in step 1 is preferably 1 mol or more, considering the amount of unsaturated bonds introduced into the polyester resin, with respect to the total of 100 mol of the alcohol component and the carboxylic acid component. Preferably 2 mol or more, more preferably 4 mol or more, more preferably 7 mol or more, more preferably 10 mol or more, and from the viewpoint of maintaining the length of the main chain of the polyester resin and improving storage stability The amount is preferably 35 mol or less, more preferably 30 mol or less, still more preferably 27 mol or less, still more preferably 25 mol or less, and still more preferably 15 mol or less.

  The temperature of the polycondensation reaction in Step 1 is 180 ° C. or higher, preferably 185 ° C. or higher, more preferably 190 ° C. or higher, from the viewpoint of promoting the esterification reaction and / or transesterification reaction. From the viewpoint of suppressing the temperature, it is 250 ° C. or lower, preferably 240 ° C. or lower, more preferably 235 ° C. or lower.

  Although the pressure of the polycondensation reaction may be normal pressure, reduced pressure is preferable from the viewpoint of reactivity. The reduced pressure is a pressure less than normal pressure (101.3 kPa), preferably 80 kPa or less, more preferably 50 kPa or less, further preferably 20 kPa or less, and preferably 1 kPa or more, more preferably 3 kPa or more, and even more preferably. Is 5 kPa or more.

  The reaction time is 1 hour or longer, preferably 2 hours or longer, more preferably 3 hours or longer, more preferably 5 hours or longer, and preferably 40 hours or longer from the viewpoint of proceeding the esterification reaction and / or transesterification reaction. It is not more than time, more preferably not more than 35 hours, further preferably not more than 30 hours, further preferably not more than 25 hours.

  The polycondensation reaction in step 1 may be performed in the presence of an esterification catalyst, an esterification cocatalyst, or the like, if necessary.

  Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamate. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Preferably it is 1.0 mass part or less.

  Examples of the esterification promoter include gallic acid. The amount of esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. More preferably, it is 0.1 parts by mass or less.

  The acid value of the polyester resin obtained in Step 1 is 5.0 mgKOH / g or less, preferably 4.0 mgKOH / g or less, more preferably 3.0 mgKOH / g, in order to obtain a toner in which the polyester resin portion and the styrene acrylic resin are uniformly dispersed. g or less.

  Further, the sum of the acid value and the hydroxyl value of the polyester resin obtained in Step 1 is preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, in order to seal the terminal of the polyester resin with an unsaturated bond. Preferably it is 15 mgKOH / g or less, More preferably, it is 10 mgKOH / g or less.

  The softening point of the polyester resin is preferably 40 ° C or higher, more preferably 60 ° C or higher, more preferably 80 ° C or higher, from the viewpoint of excellent low-temperature fixability and heat-resistant storage stability, and from the viewpoint of low-temperature fixability, Preferably it is 150 degrees C or less, More preferably, it is 120 degrees C or less, More preferably, it is 100 degrees C or less.

  The number average molecular weight of the polyester resin is preferably 3,000 or more, more preferably 4,000 or more, further preferably 5,000 or more, from the viewpoint of heat-resistant storage stability, and from the viewpoint of production of the polyester resin, preferably 15,000 or less, More preferably, it is 12,000 or less, and more preferably 10,000 or less.

  The weight average molecular weight of the polyester resin is preferably 8,000 or more, more preferably 10,000 or more, even more preferably 15,000 or more, from the viewpoint of heat-resistant storage stability, and from the viewpoint of production of suspended particles, preferably 100,000 or less. More preferably, it is 50,000 or less, and further preferably 30,000 or less.

Step 2 is a step of subjecting a polymerizable monomer composition obtained by dissolving at least the polyester resin, the colorant, and the release agent obtained in Step 1 to a raw material monomer of a styrene acrylic resin in a water-based medium by suspension polymerization. is there.
In step 2, the following two types of resins are present in the system, namely, a styrene acrylic resin as a toner base resin, and a resin in which an unsaturated bond of a styrene acrylic resin and a polyester as a toner base resin is polymerized. Since the former styrene acrylic resin and the latter styrene acrylic resin are polymerized under the same conditions (same temperature, same initiator, same time), the molecular weight distribution can be very close. For this reason, the dispersibility of the polyester resin in the toner is very excellent. On the other hand, when a polyester resin combined with a styrene acrylic resin of the same degree as that of the present invention is added in step 2, the molecular weight of the polyester resin is higher than that of the present invention at the stage before polymerization, so the viscosity in the system is high. Therefore, it becomes difficult to produce sufficiently uniform particles with shearing force during suspension.

  As raw material monomers for the styrene acrylic resin, at least a styrene compound and an alkyl (meth) acrylate are used. In the present specification, “(meth) acrylic acid alkyl ester” means an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester.

  Examples of the styrene compound include styrene derivatives such as styrene, α-methylstyrene, and vinyl toluene, and styrene is preferable.

  The content of the styrene compound, preferably styrene, is preferably 55% by mass or more, more preferably 65% by mass or more, and further preferably 70% by mass in the raw material monomer of the styrene acrylic resin, from the viewpoint of low-temperature fixability and color developability. More preferably, it is 75% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less.

  Examples of (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (iso or tertiary) butyl (meth) Examples include acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) decyl (meth) acrylate, and (iso) stearyl (meth) acrylate. It is preferable to use one or more of these. Here, “(iso or tertiary)” and “(iso)” mean that both of these groups are present and not present, and when these groups are not present Indicates normal. Further, “(meth) acrylate” indicates that both acrylate and methacrylate are included.

  The carbon number of the alkyl group in the (meth) acrylic acid alkyl ester is preferably 1 or more, more preferably 3 or more, from the viewpoint of suppressing evaporation during the production of the polyester resin, and from the viewpoint of heat-resistant storage stability, Is 22 or less, more preferably 15 or less. In addition, carbon number of this alkyl ester means carbon number derived from the alcohol component which comprises ester.

  The content of the (meth) acrylic acid alkyl ester is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass, from the viewpoint of low-temperature fixability and color developability in the raw material monomer of the styrene acrylic resin. %, And preferably 45% by mass or less, more preferably 35% by mass or less, further preferably 30% by mass or less, and further preferably 25% by mass or less.

  Raw material monomers for styrene acrylic resins include raw material monomers other than styrene compounds and (meth) acrylic acid alkyl esters, for example, divinylbenzene compounds such as divinylbenzene; ethylenically unsaturated monoolefins such as ethylene and propylene; butadiene and the like Diolefins; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic acid esters such as dimethylaminoethyl (meth) acrylate; vinyl ethers such as vinyl methyl ether; vinylidene chloride And vinylidene halides such as N-vinyl compounds such as N-vinylpyrrolidone.

  In the polymerizable monomer composition, the content of the polyester resin obtained in step 1 is preferably 2 parts by mass or more from the viewpoint of low-temperature fixability with respect to 100 parts by mass of the styrene acrylic resin raw material monomer. Preferably 4 parts by mass or more, more preferably 7 parts by mass or more, and from the viewpoint of storage stability, color developability, and toner scattering suppression, preferably 30 parts by mass or less, more preferably 25 parts by mass or less, The amount is preferably 20 parts by mass or less.

  In Step 2, a known binder resin or its raw material monomer may be dissolved in the raw material monomer of styrene acrylic resin together with the polyester resin and styrene acrylic resin obtained in Step 1. That is, in the toner obtained by the method of the present invention, a known binder resin for toner other than the polyester resin and the styrene acrylic resin obtained in Step 1 can be used as the binder resin as long as the effects of the present invention are not impaired. The raw material monomer, for example, other polyester resin, epoxy resin, polycarbonate, polyurethane or the like resin or the raw material monomer may be used in combination, but the polyester resin obtained in Step 1 and the styrene acrylic resin or the raw material monomer The total content is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, in the binder resin. Preferably it is 100 mass%.

  As the colorant, all of dyes and pigments used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow and the like can be used, and the toner of the present invention may be either a black toner or a color toner.

  The content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass with respect to 100 parts by mass of the binder resin from the viewpoint of improving the color developability of the toner. Part or less, more preferably 10 parts by weight or less.

  The release agent is preferably one or more selected from the group consisting of hydrocarbon waxes and ester waxes from the viewpoint of low-temperature fixability, and hydrocarbon waxes are preferable from the viewpoint of toner scattering suppression.

  Examples of the hydrocarbon wax include polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax; aliphatic hydrocarbon wax such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, sazol wax, or oxides thereof. Of these, paraffin wax is preferred.

  Examples of the ester wax include carnauba wax, montan wax, deoxidized wax thereof, and fatty acid ester wax.

  Examples of other release agents include fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, and the like, and these can be used alone or in admixture of two or more.

  The melting point of the release agent is preferably 60 ° C. or higher, more preferably 70 ° C. or higher from the viewpoint of toner transferability, and preferably 90 ° C. or lower, more preferably 85 ° C. from the viewpoint of low-temperature fixability. Below, it is 80 degrees C or less more preferably.

  The content of the release agent is preferably 1 part by mass or more with respect to 100 parts by mass of the binder resin from the viewpoint of low-temperature fixability and offset resistance of the toner and dispersibility in the binder resin. The amount is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less.

  The polymerizable monomer composition may contain additives such as a charge control agent, magnetic powder, a conductivity modifier, a reinforcing filler such as a fibrous substance, and an antioxidant. It is preferable that an agent and a charge control agent are contained.

The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.
Examples of positively chargeable charge control agents include nigrosine dyes such as “Nigrosine Base EX”, “Oil Black BS”, “Oil Black SO”, “Bontron N-01”, “Bontron N-04”, “Bontron N-07 ”,“ Bontron N-09 ”,“ Bontron N-11 ”(manufactured by Orient Chemical Co., Ltd.), etc .; triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds, for example “Bontron P-51” (manufactured by Orient Chemical Co., Ltd.), cetyltrimethylammonium bromide, “COPY CHARGE PX VP435” (manufactured by Clariant), etc .; polyamine resins such as “AFP-B” (Orient Chemical Co., Ltd.) Imidazole derivatives such as “PLZ-2001”, “PLZ-8001” (manufactured by Shikoku Kasei Kogyo Co., Ltd.), etc .; styrene-acrylic resins such as “FCA-701PT” (Fujikura Kasei Co., Ltd.) ), And the like.

  In addition, as the negatively chargeable charge control agent, metal-containing azo dyes such as “Varifast Black 3804”, “Bontron S-31”, “Bontron S-32”, “Bontron S-34”, “Bontron S-36” (Above, Orient Chemical Industry Co., Ltd.), “Eisenspiron Black TRH”, “T-77” (Hodogaya Chemical Co., Ltd.), etc .; metal compounds of benzylic acid compounds, such as “LR- 147 ”,“ LR-297 ”(manufactured by Nippon Carlit Co., Ltd.), etc .; metal compounds of salicylic acid compounds, such as“ Bontron E-81 ”,“ Bontron E-84 ”,“ Bontron E-88 ”,“ "Bontron E-304" (manufactured by Orient Chemical Co., Ltd.), "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.), etc .; copper phthalocyanine dyes; quaternary ammonium salts such as "COPY CHARGE NX VP434" (Manufactured by Clariant), nitroimidazole derivatives, etc .; organic gold Genus compounds and the like.

  The content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass with respect to 100 parts by mass of the binder resin from the viewpoint of charge stability of the toner. Parts or less, more preferably 5 parts by mass or less, further preferably 3 parts by mass or less, and further preferably 2 parts by mass or less.

  The polymerizable monomer composition is prepared by mixing the styrene acrylic resin raw material monomer with the polyester resin obtained in step 1, a release agent and a colorant, and, if necessary, an additive such as a charge control agent, It is preferable to prepare by dissolving the polyester resin by heating or the like. You may add a chain transfer agent, a plasticizer, and an oil agent.

  The aqueous medium preferably contains water in an amount of 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and further preferably 99% by mass or more. Water alone may be used, but a solvent miscible with water may be used in combination. Solvents miscible with water include alcohols (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolve (registered trademark) (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), etc. It is done.

  The amount of the aqueous medium is preferably 3 times by mass or more, more preferably 5 times by mass or more of the raw material monomer of the styrene acrylic resin, from the viewpoint of controlling the particle size of the toner particles, and preferably from the viewpoint of productivity. It is less than mass times, more preferably less than 8 times mass.

  It is preferred that the polymerizable monomer composition is mixed with an aqueous medium and stirred to form a suspension, and then the styrene acrylic resin raw material monomer is subjected to suspension polymerization.

  For the stirring of the polymerizable monomer composition and the aqueous medium, a high-speed disperser such as a homomixer, a high-speed stirrer, or an ultrasonic disperser can be used, whereby the polymerizable monomer is uniformly distributed in the aqueous medium. It is possible to easily prepare a suspension.

  The stirring of the polymerizable monomer composition and the aqueous medium is preferably performed under heating conditions in a nitrogen atmosphere.

  Suspension polymerization of the raw material monomer of the styrene acrylic resin is performed with stirring so that the particles of the polymerizable monomer composition in the suspension maintain the particle state and the particles do not float or settle. It is preferable.

  Suspension polymerization is preferably performed in the presence of a dispersion stabilizer, and the dispersion stabilizer is preferably added to an aqueous medium in advance. The dispersion stabilizer is preferably a phosphate or a surfactant from the viewpoint of manufacturability of toner particles, and these can be used alone or in combination. Therefore, the suspension polymerization is preferably performed in the presence of a phosphate and a surfactant.

Examples of the phosphate include tricalcium phosphate (tricalcium phosphate), magnesium phosphate, aluminum phosphate, zinc phosphate, and the like. Among these, tricalcium phosphate is preferable. It is preferable to use one or more of these. Here, examples of molecular formulas of tricalcium phosphate include Ca ₃ (PO ₄ ) ₂ , 3 [Ca ₃ (PO ₄ ) ₂ ] · Ca (OH) ₂ , 3Ca ₃ (PO ₄ ) ₂ · Ca (OH ) ₂ , Ca ₁₀ (PO ₄ ) ₆ (OH) _{2 and the} like.

  The amount of phosphate used is preferably 3 parts by mass or more, more preferably 20 parts by mass or more, from the viewpoint of production stability, with respect to 100 parts by mass of the raw material monomer of the styrene acrylic resin, and at the time of production. From the viewpoint of cost, it is preferably 200 parts by mass or less, more preferably 100 parts by mass or less.

  Examples of the surfactant include nonionic surfactants and anionic surfactants.

  Nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyalkylene alkenyl ether, sorbitan monolaurate, sorbitan monopalmi Examples include tate, sorbitan monolaurate, sorbitan monopalmitate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monolaurate, polyethylene glycol monolaurate, polyethylene glycol monostearate and the like.

  Anionic surfactants include sodium lauryl sulfate, ammonium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, sodium dialkyl sulfosuccinate, sodium alkane sulfonate, β-naphthalene sulfonate formalin Examples include sodium salts of condensates.

The surfactant concentration in the aqueous medium is preferably 10 ⁻³ M or less, more preferably 10 ⁻² M or less, even more preferably 10 ⁻³ M or less, and preferably from the viewpoint of toner particle manufacturability. Is greater than 0M.

  The temperature of the suspension polymerization is preferably 55 ° C. or higher, more preferably 60 ° C. or higher, more preferably 65 ° C. or higher, from the viewpoint of manufacturability and color development, and preferably from the viewpoint of the thermal properties of the toner. 90 ° C. or lower, more preferably 85 ° C. or lower, and further preferably 80 ° C. or lower.

  The suspension polymerization time is preferably 4 hours or more, more preferably 6 hours or more from the viewpoint of terminating the polymerization reaction, and preferably 20 hours or less, more preferably 15 hours, from the viewpoint of suppressing fine particle aggregation. It is as follows.

  The suspension polymerization is preferably carried out in the presence of a polymerization initiator as necessary.

  Examples of the polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile). ), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and other azo polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2 1, 4-dichlorobenzoyl peroxide, lauroyl peroxide, and other peroxide polymerization initiators, and those soluble in the raw material monomer of the styrene acrylic resin are preferred.

  The 10-hour half-life temperature of the polymerization initiator is preferably 40 ° C. or higher, more preferably 45 ° C. or higher, more preferably 50 ° C. or higher, and preferably 80 ° C. or lower, from the viewpoints of manufacturability and color developability. More preferably, it is 75 degrees C or less, More preferably, it is 70 degrees C or less.

  The amount of the polymerization initiator used is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, and preferably 20 parts by mass or less, more preferably, with respect to 100 parts by mass of the styrene acrylic resin raw material monomer. 10 parts by mass or less.

  The polymerization initiator may be mixed with other additives when preparing the polymerizable monomer composition, or may be mixed into the polymerizable monomer composition just before being suspended in the aqueous medium. Good. Moreover, it can also be added in the state melt | dissolved in the polymerizable monomer and other solvent as needed during granulation or after completion of granulation, ie, just before starting a polymerization reaction. The polymerization reaction is preferably terminated when the raw material monomer of the styrene acrylic resin has reacted preferably at least 95 mol%, more preferably at least 98 mol%. The amount of residual monomer at the end of the reaction is preferably 5000 ppm (wt / wt) or less with respect to the produced styrene acrylic resin.

  After the polymerization, the residual monomer is removed by a conventional method, and the toner particles are obtained by cooling to room temperature while continuing stirring, washing and drying.

  The toner particles are preferably subjected to an external addition treatment mixed with an external additive in order to improve transferability. Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide and zinc oxide, and organic fine particles such as resin particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles. The above may be used in combination. Among these, silica is preferable, and hydrophobic silica that has been subjected to a hydrophobic treatment is more preferable from the viewpoint of toner transferability.

  Examples of the hydrophobizing agent for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), and methyltriethoxysilane. It is done.

  The average particle diameter of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and preferably 250 nm or less, more preferably 200 nm or less, from the viewpoint of toner chargeability, fluidity, and transferability. Preferably it is 90 nm or less.

  The amount of the external additive used is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass with respect to 100 parts by mass of the toner before being processed with the external additive, from the viewpoint of chargeability, fluidity, and transferability of the toner. Part or more, more preferably 0.3 part by weight or more, and preferably 5 parts by weight or less, more preferably 3 parts by weight or less.

The volume median particle size (D ₅₀ ) of the toner obtained by the method of the present invention is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size. When the toner is treated with an external additive, the volume median particle size of the toner particles before being treated with the external additive is defined as the volume median particle size of the toner.

  The glass transition temperature of the toner is preferably 35 ° C. or higher, more preferably 40 ° C. or higher, more preferably 45 ° C. or higher, from the viewpoint of heat-resistant storage stability, and preferably 90 ° C. or lower from the viewpoint of low-temperature fixability. More preferably, it is 80 ° C. or less, and further preferably 70 ° C. or less.

  The toner obtained by the method of the present invention preferably has a sharp particle size distribution and a high degree of circularity from the viewpoint of reducing toner scattering. From such a viewpoint, the CV value of the particle size distribution of the toner is preferably 40% or less, more preferably 33% or less, and the circularity of the toner is preferably 0.980 or more, more preferably 0.985 or more.

  The toner of the present invention can be used as a one-component developing toner or as a two-component developer mixed with a carrier.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The physical properties of the resin and the like were measured by the following method.

[Softening point of resin]
Using a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C./min, and a 1.96 MPa load was applied by a plunger, and the diameter was 1 mm and the length was 1 mm. Extrude from the nozzle. The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[Maximum peak temperature of resin endotherm]
Using a differential scanning calorimeter “Q-100” (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of a sample is weighed into an aluminum pan, and the temperature is reduced from room temperature to 10 ° C./min. Cool to 0 ° C. and maintain for 1 minute. Thereafter, the measurement is performed at a heating rate of 10 ° C./min. Among the observed endothermic peaks, the peak temperature at the highest temperature side is defined as the highest endothermic peak temperature.

[Acid value and hydroxyl value of resin]
Measured according to the method of JIS K 0070. However, only the measurement solvent is changed from the ethanol / ether mixed solvent specified in JIS K 0070 to the acetone / toluene mixed solvent (acetone: toluene = 1: 1 (volume ratio)).

[Number average molecular weight and weight average molecular weight of the resin]
The number average molecular weight and the weight average molecular weight are determined by gel permeation chromatography (GPC) by the following method.
(1) Preparation of sample solution Dissolve the sample in tetrahydrofuran at 40 ° C so that the concentration is 0.5 g / 100 mL. Next, this solution is filtered using a PTFE type membrane filter “DISMIC-25JP” (manufactured by Toyo Roshi Kaisha, Ltd.) having a pore size of 0.20 μm to remove insoluble components to obtain a sample solution.
(2) Molecular weight measurement Using the following measuring device and analytical column, tetrahydrofuran is flowed as an eluent at a flow rate of 1 mL per minute, and the column is stabilized in a constant temperature bath at 40 ° C. Inject 100 μL of the sample solution into the sample and perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several types of monodisperse polystyrene (A-500 (5.0 × 10 ² ), A-1000 (1.01 × 10 ³ ), A-2500 (2.63 × 10 ³ ) manufactured by Tosoh Corporation, A-5000 (5.97 × 10 ³ ), F-1 (1.02 × 10 ⁴ ), F-2 (1.81 × 10 ⁴ ), F-4 (3.97 × 10 ⁴ ), F-10 (9.64 × 10 ⁴ ), F-20 (1.90 × 10 ⁵ ), F-40 (4.27 × 10 ⁵ ), F-80 (7.06 × 10 ⁵ ), F-128 (1.09 × 10 ⁶ )) prepared as standard samples are used. The molecular weight is shown in parentheses.
Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation)
Analytical column: TSKgel GMH _XL + TSKgel G3000H _XL (manufactured by Tosoh Corporation)

[Melting point of release agent]
Using a differential scanning calorimeter “DSC Q20” (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan and heated to 200 ° C. at a heating rate of 10 ° C./min. The temperature is raised and the temperature is cooled to -10 ° C at a rate of 5 ° C / min. Next, the sample is heated to 180 ° C. at a heating rate of 10 ° C./min and measured. The maximum peak temperature of the endotherm observed from the melting endotherm curve thus obtained is taken as the melting point of the release agent.

[Average particle diameter of external additive]
The average particle diameter refers to the number average particle diameter. The particle diameter (average value of major axis and minor axis) of 500 particles is measured from a scanning electron microscope (SEM) photograph, and the number average value thereof is used.

[Volume-median particle diameter (D ₅₀ ) and CV value of toner]
Measuring machine: Coulter Multisizer II (manufactured by Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter, Inc.)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (Griffin): 13.6) dissolved in the electrolyte to adjust to 5% by mass Dispersion condition: 10 mL of measurement sample in 5 mL of the dispersion Is added for 1 minute with an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W), and then 25 mL of the electrolyte is added. For 1 minute to prepare a sample dispersion.
Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte so that the particle size of 30,000 particles could be measured in 20 seconds, and 30,000 particles were measured. Determine the median particle size (D ₅₀ ).
The CV value (%) is calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

[Glass transition temperature of toner]
Using a differential scanning calorimeter “DSC Q20” (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample was weighed into an aluminum pan, heated to 200 ° C., and the temperature dropped from that temperature. Cool to 0 ° C at a rate of 10 ° C / min. Next, the sample is heated and measured at a heating rate of 10 ° C./min. The glass transition temperature is defined as the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Toner circularity]
The circularity of the toner is measured under the following conditions.
・ Measuring machine: Wet flow particle size / shape analyzer “FPIA-3000” (Malvern Instruments Ltd)
-Dispersion: Polyoxyethylene lauryl ether “Emulgen 109P” (manufactured by Kao Corporation), HLB (Griffin): 13.6) dissolved in the electrolyte, and adjusted to 5% by mass.
-Dispersion conditions: 50 mg of a measurement sample was added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, then 20 mL of distilled water was added, and further dispersed for 1 minute with an ultrasonic disperser.

Examples 1 to 20 and Comparative Examples 1 to 4 (Examples 5 and 6 are reference examples)
[Step 1]
<Resin A to H, J to P, R>
The total amount of the polyester resin raw material monomers and (meth) acrylic acid compounds shown in Tables 1 to 3 is 10 equipped with a thermometer, a stainless steel stirring rod, a dehydration pipe equipped with a cooling pipe, a flow-down condenser, and a nitrogen introduction pipe. In a 4-liter flask having a volume of 1 liter and heated in a mantle heater in a nitrogen atmosphere over 6 hours from 140 ° C. to 200 ° C., tin (II) 2-ethylhexanoate shown in Tables 1 to 3 and Gallic acid was added and held at 200 ° C. for 1 hour. Then, the polyester resin was obtained by hold | maintaining at 8 kPa for 1 hour.

<Resin I>
The total amount of raw material monomers and (meth) acrylic acid compound of polyester resin excluding adipic acid shown in Table 2 is added to a thermometer, a stainless steel stirring rod, a dehydration pipe equipped with a cooling pipe, a flow-down condenser, and a nitrogen introduction pipe. Place in a equipped 10 liter four-necked flask, add tin (II) 2-ethylhexanoate and gallic acid shown in Table 2 in a mantle heater under a nitrogen atmosphere, and then raise the temperature to 235 ° C. Hold at 223 ° C. for 6 hours. Thereafter, the temperature was lowered to 190 ° C., adipic acid shown in Table 2 was added, the temperature was raised to 200 ° C., and the reaction was continued until the desired thermophysical properties were obtained at 8 kPa to obtain a polyester resin.

<Resin Q>
The total amount of polyester resin raw material monomer and (meth) acrylic acid compound shown in Table 3 is 10 liters equipped with a thermometer, a stainless steel stirring rod, a dehydration tube equipped with a cooling tube, a flow-down condenser, and a nitrogen introduction tube. After raising the temperature from 140 ° C to 200 ° C over 6 hours in a mantle heater in a nitrogen atmosphere, the temperature inside the system was lowered to 170 ° C, and Table 3 shows styrene acrylic resin. All the raw material monomers and the polymerization initiator were added dropwise over 1 hour. After maintaining at 170 ° C. for 1 hour, the temperature was raised to 200 ° C. and maintained at 8 kPa for 1 hour to obtain a composite resin.

[Step 2]
<Examples 1-7, 10, 11, 14-18, Comparative Examples 2-4>
In a 300 mL glass beaker, 10 g of the resin obtained in Step 1 shown in Tables 4 and 5, 85 g of styrene, 15 g of n-butyl acrylate, and coloring agent “Pigment Blue 15: 3” (manufactured by Dainichi Seika Kogyo Co., Ltd.) ) 5g, charge control agent "Bontron E-88" (Orient Chemical Co., Ltd., aluminum salicylate) 1g, mold release agent "HNP-9" (Nippon Seiwa Co., Ltd., paraffin wax, melting point: 75 15 g) was stirred and mixed, and heated to 60 ° C. to dissolve uniformly. Thereafter, 4 g of a polymerization initiator “V-65” (manufactured by Wako Pure Chemical Industries, Ltd., 2,2′-azobis (2,4-dimethylvaleronitrile)), 10-hour half-life temperature: 51 ° C.) was added. A resin solution was prepared. In a 1-liter glass beaker, 150 g of ion-exchanged water, 10 wt% slurry of tribasic calcium phosphate (3 [Ca ₃ (PO ₄ ) ₂ ] · Ca (OH) ₂ ) “TCP-10 · U” (Taihei Chemical Industry ( 500 g) and 0.004 g of anionic surfactant “Neopelex G-15” (Kao Co., Ltd., sodium dodecylbenzenesulfonate) are added and stirred in an aqueous medium (surfactant concentration: 1.1 × 10 ^-5 M) was prepared. Heat the aqueous medium to 60 ° C and keep the temperature at 60 ° C. Add the resin solution all at once and stir for 4 minutes at 12,000r / min with Homomixer MARK II 2.5 (Primix Co., Ltd.). Got.

The suspension was transferred to a separable flask and polymerized for 7 hours while stirring at 70 ° C. and 200 r / min. Thereafter, the temperature was raised to 80 ° C., and the remaining monomer was distilled off under reduced pressure. While continuing stirring, the mixture was cooled to 20 ° C., and hydrochloric acid was added until the pH in the system became 1 or less. After washing and drying, particles having a volume-median particle size (D ₅₀ ) of 8.0 μm were obtained.

[External addition process]
To 100 parts by mass of the particles, 1.0 part by mass of hydrophobic silica “Aerosil R-972” (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: DMDS, average particle size: 16 nm) was added as an external additive, and Henschel mixer was added. Were mixed at 3600 r / min for 5 minutes to perform external additive treatment, and thus a toner was obtained.

<Examples 8 and 9>
The polymerization temperature after transferring the suspension to a separable flask (70 ° C. in Example 1) was changed to 65 ° C. in Example 8 and 75 ° C. in Example 9. A toner was obtained.

<Examples 12 and 13>
As a mold release agent, instead of “HNP-9”, in Example 12, “WEP-8” (manufactured by NOF Corporation, ester wax, melting point: 75 ° C.) 15 g, in Example 13, “HNP-1” A toner was obtained in the same manner as in Example 1, except that 15 g (manufactured by Nippon Seiwa Co., Ltd., paraffin wax, melting point: 64 ° C.) was used.

<Examples 19 and 20>
The amount of the resin (resin A) obtained in step 1 (10 g in Example 1) was changed to 5 g in Example 19 and 30 g in Example 20, and the toner was changed in the same manner as in Example 1. Obtained.

<Comparative Example 1>
Production of toner was attempted in the same manner as in Example 1. In Step 2, the suspension was transferred to a separable flask, polymerized for 7 hours while stirring at 70 ° C. and 200 r / min, and then heated to 80 ° C. When the residual monomer was distilled off under reduced pressure and the mixture was cooled to 20 ° C. while continuing to stir, many lumps of several centimeters were formed in the system, and toner could not be formed.

<Comparative Example 4>
An attempt was made to produce a toner in the same manner as in Example 1. However, after polymerization for 7 hours, some particles floated on the liquid surface and two-phase separation occurred, so that the toner could not be formed.

Test Example 1 [storage stability]
10 g of toner was put in a cylindrical container having a radius of 12 mm, and a weight of 100 g was placed on the top, and kept in an environment of 50 ° C. and 60% relative humidity for 72 hours.
In order from the top, a powder tester (manufactured by Hosokawa Micron Co., Ltd.) is installed with three sieves of sieve A (aperture 250 μm), sieve B (aperture 150 μm), and sieve C (aperture 75 μm). A toner (10 g) was placed on A and vibrated for 60 seconds.
The toner mass WA (g) remaining on the sieve A, the toner mass WB (g) remaining on the sieve B, and the toner mass WC (g) remaining on the sieve C are measured, respectively.
α = 100− (WA + WB × 0.6 + WC × 0.2) / 10 × 100
The storage stability was evaluated based on the value (α) calculated according to the above. The results are shown in Tables 4 and 5. The closer the value (α) is to 100, the better the storage stability. The value (α) is preferably 55 or more, more preferably 70 or more, and even more preferably 85 or more.

Test Example 2 [low temperature fixability]
The fixing machine of the copier “AR-505” (manufactured by Sharp Corporation) has been improved so that it can be fixed outside the machine. Toner is mounted on this device, and the printed matter is unfixed on Sharp's paper [CopyBond SF-70NA (75 g / m ² )] so that the toner adhesion amount is 0.5 mg / cm ^2. Obtained. Using a fixing machine (fixing speed 200mm / sec) adjusted so that the total fixing pressure is 40kgf, the fixing roller temperature is gradually increased from 90 ° C to 240 ° C in 5 ° C increments, and the unfixed state at each temperature. The fixing test of the printed material was conducted.
A sand eraser with a bottom of 15 mm x 7.5 mm under a load of 500 g. The image fixed through the fixing machine is rubbed 5 times, and the reflection density meter "RD-915" (manufactured by Macbeth Co.) The fixing roller temperature at which the ratio between the two (after rubbing / before rubbing) first exceeded 70% was defined as the minimum fixing temperature. The results are shown in Tables 4 and 5. The lower the minimum fixing temperature, the better the low-temperature fixing property. The minimum fixing temperature is preferably 165 ° C or lower, more preferably 150 ° C or lower, and further preferably 140 ° C or lower.

Test Example 3 [Color development]
Place 3.0g of toner in a powder measurement container (diameter 2.5cm, height 5cm), cap the container, drop it 10 times from a height of about 5mm on a flat desk, smooth the surface, and then sample the measurement container The sample was set on a table, and the L value was measured with a color difference meter (SZ-Σ80, Nippon Denshoku Co., Ltd. equivalent). The results are shown in Tables 4 and 5. The lower the L value, the darker the color and the better the color developability. The L value is preferably 42 or less, more preferably 39 or less, and even more preferably 37 or less.

Test Example 4 [Toner scattering suppression]
The image drum unit (ID-C4BC) of the non-magnetic one-component development printer "MICROLINE 5400" (Oki Data Co., Ltd.) is cleaned, the internal toner is removed, the photoconductor is removed, and 30 g of toner is enclosed. Was driven for 1 hour at 200r / min with an external jig. After driving, the toner (scattered toner) accumulated in the tray installed at the bottom of the developing unit was collected, and the amount (scattered amount) was Measured. The results are shown in Tables 4 and 5. The smaller the amount of scattering, the better the scattering suppression, preferably 200 mg or less, more preferably 50 mg or less.

From the above results, it can be seen that the toners of Examples 1 to 20 are excellent in toner low-temperature fixability, color developability, and scattering suppression while maintaining storage stability.
On the other hand, in Comparative Example 1 in which the polyester resin obtained in Step 1 has a high acid value, the particle size distribution cannot be narrowed, and uniform toner particles are not obtained.
Further, in the toner of Comparative Example 2 in which the (meth) acrylic acid compound is not used in Step 1, the polyester resin has no reaction site with the styrene acrylic resin, and the dispersibility of the styrene acrylic resin in the raw material monomer is low. It is not maintained in a good state, and the dispersibility of the polyester in the toner is deteriorated. In particular, the fixability and color developability are deteriorated, and the occurrence of toner scattering is remarkable.
Further, in the toner of Comparative Example 3 in which the composite resin obtained by combining the polyester resin with the styrene acrylic resin in Step 1 is obtained, the toner scattering is remarkable. This is because, as in the example, after the polyester resin was obtained in the step 1 in advance, the polyester resin was combined with the styrene acrylic resin under the suspension polymerization in the step 2, whereas the styrene acrylic in the composite resin was used. It is estimated that the resin portion is short.
Furthermore, as in Comparative Example 4, when an aliphatic raw material monomer having an unsaturated bond is used as a part of the raw material monomer of the polyester resin instead of the (meth) acrylic acid compound, it is included in the molecular chain of the polyester resin. A number of unsaturated bonds are introduced. Since the polyester resin having a large number of unsaturated bonds in the molecular chain acts like a cross-linking agent during suspension polymerization in Step 2, two-phase separation or the like occurs as in Comparative Example 4, and toner manufacturability is increased. Getting worse.

  The toner for electrophotography obtained by the method of the present invention is used for developing a latent image formed in an electrostatic image developing method, an electrostatic recording method, an electrostatic printing method, or the like.

Claims (9)

Step 1: A raw material monomer of a polyester resin containing an alcohol component and a carboxylic acid component, and a (meth) acrylic acid-based compound containing a (meth) acrylic acid alkyl ester having 4 to 22 carbon atoms at 180 ° C. A step of obtaining a polyester resin having an acid value of 5.0 mgKOH / g or less (excluding a composite resin in which a styrene acrylic resin is combined with a polyester resin) by polycondensing at 250 ° C. or lower for 1 hour or longer and step 2: An electrophotographic process comprising a step of suspension polymerization of a polymerizable monomer composition obtained by dissolving at least the polyester resin, the colorant, and the release agent obtained in Step 1 in a raw material monomer of a styrene acrylic resin in an aqueous medium; Of manufacturing toner.   The production of an electrophotographic toner according to claim 1, wherein in step 1, the amount of the (meth) acrylic acid compound used is 2 mol or more and 35 mol or less with respect to a total of 100 mol of the alcohol component and the carboxylic acid component. Method. The amount of the polyester resin obtained in the step 1 in the polymerizable monomer composition in the step 2 is 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the raw material monomer of the styrene acrylic resin. 3. A method for producing an electrophotographic toner according to 1 or 2 . The method for producing an electrophotographic toner according to any one of claims 1 to 3 , wherein the sum of the acid value and the hydroxyl value of the polyester resin obtained in step 1 is 20 mgKOH / g or less. Melting point of the release agent is 60 ° C. or higher 90 ° C. or less, according to claim 1-4 method of manufacturing toner for electrophotography according to any one. Release agent, is one or more selected from the group consisting of hydrocarbon waxes and ester waxes, claim 1-5 method of manufacturing toner for electrophotography according to any one. Alcohol component as a raw material monomer of the polyester resin, containing 6 or more aliphatic diols carbon, claim 1-6 method of manufacturing toner for electrophotography according to any one. The electrophotography according to any one of claims 1 to 7 , wherein the suspension polymerization in step 2 is carried out at a temperature of 55 ° C to 90 ° C in the presence of a polymerization initiator having a 10-hour half-life temperature of 40 ° C to 80 ° C. Of manufacturing toner. The suspension in step 2 is carried out in the presence of phosphate and surfactant, it claims 1-8 method of manufacturing toner for electrophotography according to any one.