JP5084535B2 - Method for producing toner particles - Google Patents

Description

  The present invention relates to a toner and a toner particle manufacturing method for developing an electrostatic image in an image forming method such as electrophotography, electrostatic printing, and magnetic recording. In particular, the present invention relates to a dry toner manufacturing method for use in a fixing method in which an image formed of toner is heated and fixed on a recording material.

  Conventionally, as a toner for electrophotography, a so-called pulverized toner having a desired particle size by a fine pulverizer and a classifier is generally used after a colorant is melt-mixed and uniformly dispersed in a thermoplastic resin. It was. Although this production method can produce a considerably excellent toner, there is a problem that, when finely pulverizing at high speed, particles having a wide particle size range are easily formed and it is difficult to make fine particles. On the other hand, in order to overcome the problems of the toner by these pulverization methods, a toner production method by a suspension polymerization method has been proposed (Patent Documents 1 to 3). This suspension polymerization method is the following production method. First, a polymerizable monomer composition is obtained by uniformly dissolving or dispersing a polymerizable monomer and a colorant (and, if necessary, a polymerization initiator, a crosslinking agent and other additives). The step of obtaining the polymerizable monomer composition is usually performed under a nitrogen atmosphere or open to the atmosphere. Further, a polymerization initiator is mixed into the polymerizable monomer composition. Next, the toner particles having a desired particle diameter are obtained by dispersing in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase, using an appropriate stirrer and performing radical polymerization using the above-described polymerization initiator. Can be obtained.

  In general, the adjustment of the molecular weight of the binder resin in the production of toner particles by the suspension polymerization method includes the preparation of the type and amount of the polymerization initiator, and the control of the reaction conditions such as the polymerization temperature. Further, a chain transfer agent, a polymerization inhibitor and the like can be further added and used (Patent Documents 4 and 5).

  With such a method, it is possible to some extent to control the degree of polymerization of the toner particles within a certain range. Addition of chain transfer agent, polymerization inhibitor, etc. and accompanying increase in the amount of polymerization initiator used not only lead to an increase in cost, but chain transfer agent, polymerization inhibitor, etc., have a slight difference in the amount of addition, polymerization reaction This greatly affects the degree of polymerization of the binder resin produced by the toner, so that the developability and fixability of the toner may change greatly. Further, the chain transfer agent, the polymerization inhibitor, the polymerizable monomer, etc. remaining in the toner particles affect the developability and fixability of the toner.

Japanese Patent Publication No. 36-10231 Japanese Patent Publication No. 43-10799 Japanese Patent Publication No. 51-14895 JP 09-043909 A JP 2006-221203 A

  An object of the present invention is to provide a method for producing toner particles that solves the above-described problems. The present invention is capable of easily controlling the degree of polymerization of toner particles in the production of polymerized toner particles, has a sharp molecular weight distribution, has few chain transfer agents and polymerization inhibitors in the toner particles, and remains as a polymerizable monomer. It is an object of the present invention to provide a method for producing toner particles having almost no development and excellent developability and fixability.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have mixed and / or dissolved an additive in a polymerizable monomer containing at least a colorant, and a polymerizable containing the colorant and the additive. In the preparation process for obtaining the monomer composition, the molecular weight distribution and molecular structure of the obtained toner particles can be easily controlled by adjusting the oxygen concentration in the gas phase part of the preparation container in the preparation process, and development The present inventors have found that a toner having excellent properties and fixing properties can be obtained. The features of the present invention are as follows.
(1) A preparation step in which an additive is mixed and / or dissolved in a polymerizable monomer containing at least a colorant to obtain a polymerizable monomer composition containing the colorant and the additive; A granulation step of granulating the monomer composition into particles having a size corresponding to the particle size of the toner particles in an aqueous medium, and the polymerizability in the polymerizable monomer composition granulated in the granulation step A method for producing toner particles comprising a polymerization step of obtaining toner particles by polymerizing monomers,
In the preparation step, the oxygen concentration C (vol%) of the gas phase portion of the preparation container containing the polymerizable monomer composition is set to 1 ≦ C ≦ 15.
A method for producing toner particles, wherein
(2) In the preparation step, the relationship between the saturated dissolved oxygen concentration S ₀ and the dissolved oxygen concentration S of the polymerizable monomer composition at the liquid temperature of the polymerizable monomer composition is 0.30 ≦ S / S ₀ ≦ 0.80
(1) The method for producing toner particles according to (1).
(3) The method for producing toner particles according to (1) or (2), wherein the preparation container is provided with a stirring blade, and the polymerizable monomer composition is stirred.
(4) The viscosity V (mPa · s) at the liquid temperature of the polymerizable monomer composition in the preparation step is as follows: V ≦ 100
The method for producing toner particles according to any one of (1) to (3) , wherein:
(5) The method for producing toner particles according to any one of (1) to (4) , wherein the polymerizable monomer contains at least a hydrophobized magnetic substance.
(6) The method for producing toner particles according to any one of (1) to (5) , wherein the polymerizable monomer contains at least a magnetic material that has been hydrophobized with a silane coupling agent.

  In the production of polymerized toner, the molecular weight distribution and molecular structure of toner particles can be easily controlled, the molecular weight distribution is sharp, the chain transfer agent and polymerization inhibitor in the toner particles are small, and the remaining polymerizable monomer is An object of the present invention is to provide a method for producing toner particles having almost no developing property and fixing property.

  The present invention will be described in more detail with reference to preferred embodiments used in the present invention.

  FIG. 1 is an example of a schematic view of a preferred preparation apparatus used in the preparation process of the present invention. In FIG. 1, 1 is a preparation container, 2 is a motor, 3 is a gas inlet for adjusting oxygen concentration, 4 is a stirring shaft, 5 is a gas phase part, 7 is a stirring blade, and 8 is a jacket.

  As a method for forming toner particles, there are a method using suspension polymerization and a solution suspension method. Suspension polymerization is a polymerization method in which polymerization proceeds in oil droplets of monomers dispersed in water. A dispersion stabilizer is used to prevent coalescence of oil droplets. A polymerization initiator that is soluble in the monomer is used. The dissolution suspension method is a method for obtaining resin fine particles by dispersing a raw material for toner in which a resin composition containing a resin is dissolved in an organic solvent in an aqueous dispersion medium, and then removing the organic solvent. .

  The present invention can be applied to a toner particle production method using a solution suspension method or suspension polymerization in which fine particles are produced by dispersing a toner raw material in an aqueous medium.

  The method for producing the toner of the present invention by the suspension polymerization method will be described below.

(Colorant dispersion process)
The polymerizable monomer is a polymerizable monomer containing a colorant that is uniformly dissolved and / or dispersed by a stirrer, a homogenizer, an ultrasonic disperser, or the like that is usually used.

  A magnetic material can be used in the toner particle manufacturing method. Hereinafter, magnetic materials that can be suitably used will be described. First, the magnetic surface is hydrophilic and the polymerizable monomer is hydrophobic. For this reason, if the hydrophobic treatment on the surface of the magnetic material is not uniform, good dispersibility of the magnetic material cannot be obtained. Further, even if the magnetic material is physically dispersed (such as mechanically or by ultrasonic dispersion), the magnetic material with non-uniform surface treatment is aggregated again and the Stokes diameter becomes large. Secondly, even if the treatment is uniform, the dispersion of the magnetic material is inferior if the polymerizable monomer that is the dispersion medium is not compatible with the magnetic material. Therefore, in the magnetic material used in the magnetic toner of the present invention, when the particle surface is hydrophobized, the coupling agent is hydrolyzed while dispersing the magnetic material particles in the aqueous medium so as to have a primary particle size. However, it is very preferable to use a surface treatment method. This hydrophobic treatment method is less likely to cause coalescence between the magnetic particles than the treatment in the gas phase, and the repulsive action between the magnetic particles due to the hydrophobic treatment works, so that the magnetic material is almost in the state of primary particles. Surface treated.

  The method of treating the surface of the magnetic material while hydrolyzing the coupling agent in an aqueous medium does not require the use of a coupling agent that generates gas, such as chlorosilanes and silazanes. Furthermore, a high-viscosity coupling agent which has been easy to unite with each other in the gas phase and has been difficult to perform well can be used, and the effect of hydrophobization is enormous.

  Examples of the coupling agent that can be used in the surface treatment of the magnetic material according to the present invention include a silane coupling agent and a titanium coupling agent. More preferably used is a silane coupling agent, and the magnetic material obtained in this way has no aggregation of particles, and since the surface of each particle is uniformly hydrophobized, the Stokes diameter becomes small and the magnetic material is magnetic. The dispersibility of the body is good.

(Preparation process)
An additive is mixed and / or dissolved in the polymerizable monomer containing the colorant described above to obtain a polymerizable monomer composition. In the following specification, the polymerizable monomer composition may be added with non-predetermined particles generated in the step of classifying the produced toner particles described later. The predetermined outer particles may be added as they are, or may be added after kneading with a kneader or the like to lower the molecular weight.

  The physical properties of the colorant-containing polysynthetic monomer composition greatly affect the molecular weight distribution and the degree of polymerization of toner particles obtained by the polymerization process described later. As described above, there is a method of controlling the degree of polymerization using a chain transfer agent, a polymerization inhibitor, etc., but the cost increases due to the addition of a chain transfer agent or polymerization inhibitor as a raw material or an increase in the amount of initiator used. There is a problem such as the influence on developability and fixability due to the remaining of these in the particles.

  Conventionally, the gas phase part of the preparation container in the preparation process has been performed in a nitrogen stream or in the presence of air. However, as a result of intensive studies, the present inventors have studied the preparation container containing the polymerizable monomer composition. It has been found that it is desirable to maintain the oxygen concentration C (vol%) in the gas phase portion at 1 ≦ C ≦ 15. When a preparation process is performed on said conditions, oxygen will melt | dissolve moderately in a polymerizable monomer composition. Thereby, the reaction rate at the initial stage of polymerization in the following polymerization step can be suppressed. Further, as the polymerization proceeds, oxygen in the system is expelled, so that the polymerization is hardly inhibited and the desired degree of polymerization is reached, and at the same time, toner particles having a sharp molecular weight distribution can be obtained and toner particles having excellent developability and fixability Can be obtained.

  In the case of C <1, the amount of oxygen dissolved in the polymerizable monomer composition is small, and the suppression of the reaction rate at the initial stage of polymerization is insufficient, and the desired degree of polymerization is not achieved. Moreover, the unreacted polymerizable monomer residual amount increases. As a result, the fixability and developability are affected.

  In the case of C> 15, the chargeability of the obtained toner particles is deteriorated and the image density is decreased, which is not preferable. This is considered to be caused by the following phenomenon. Since the oxygen dissolved in the polymerizable monomer composition becomes excessive, a polymerization termination reaction due to oxygen in the initial polymerization step often occurs, resulting in an increase in low molecular weight components in the toner particles. On the other hand, in the latter stage of the polymerization process, the amount of oxygen in the system decreases, so that polymerization inhibition is unlikely to occur. In addition, some monomers remain in the system, and the number of reaction active sites is smaller than in the initial stage of polymerization, so that the chain reaction proceeds and the degree of polymerization increases. For this reason, it is considered that the toner particle chargeability is deteriorated and the image density is decreased by increasing the molecular weight distribution of the toner particles.

The dissolved oxygen concentration S with respect to the saturated dissolved oxygen concentration S _{0 at} the liquid temperature of the colorant-containing polymerizable monomer is 0.30 ≦ S / S ₀ ≦ 0.80.
It is preferable that By performing the preparation step under the above conditions, the polymerization rate at the initial stage of polymerization can be suppressed. Furthermore, from the middle to the latter half of the polymerization step, the oxygen content in the colorant-containing polysynthetic monomer composition is almost eliminated and the polymerization rate is not hindered. Can do.

When S / S ₀ > 0.80, a large amount of polymer having a large polymerization inhibition due to oxygen at the initial stage of polymerization and a small polymerization degree is present in the toner particles. When S / S ₀ <0.30, the suppression of the reaction rate at the initial stage of polymerization is insufficient, the polymerization rate increases, and the residual monomer in the toner particles increases, which is not preferable.

  It is preferable that the preparation container which accommodates the polymerizable monomer composition in a preparation process is equipped with the stirring blade which stirs a thing. Further, the peripheral speed A (m / s) of the stirring blade is preferably in the range of 2.0 ≦ A ≦ 20.0. By stirring the polymerizable monomer composition, it becomes easier for the oxygen in the gas phase to proceed into the polymerizable monomer composition, and the peripheral speed of the stirring blade is controlled within the above range for further efficiency. In particular, the polymerizable monomer composition can be stirred. In the case of A <2.0, it is not preferable because the whole stirring tank cannot be uniformly stirred and the processed product is not sufficiently stirred and oxygen is not sufficiently taken up. In the case of A> 20.0, the agitation becomes strong and the processed material splashes on the liquid level in the air tank and adheres to the preparation container. The adhering polymerizable monomer composition is not preferable because the dispersion state of the colorant deteriorates and adversely affects the developability of the toner.

  The stirring blade is not particularly limited as long as the stirring blade can uniformly stir the contents in the preparation container, and conventionally known stirring blades having various shapes can be used. For example, anchor wing, inclined paddle wing, flat paddle wing, faddler wing, max blend wing (Sumitomo Heavy Industries, Ltd.), full zone wing (Shinko Pantech Co., Ltd.), helical ribbon wing, bull margin wing, supermix wing (Satake) Chemical machine industry), A310 wing (manufactured by LIGHTTNIN), A320 wing (manufactured by LIGHTTNIN), Intermig wing (manufactured by Equat) and the like are exemplified.

  The viscosity V (mPa · s) of the polymerizable monomer composition is preferably V ≦ 100. If V ≦ 100, convection in the preparation container of the polymerizable monomer composition is likely to occur, and the contact with the gas phase part of the polymerizable monomer composition is replaced at any time, so that oxygen can be dissolved into the system. While proceeding efficiently, the oxygen concentration in the polymerizable monomer composition becomes uniform. In the case of V> 100, convection in the polymerizable monomer composition hardly occurs or becomes slow, so that oxygen is not sufficiently dissolved in the polymerizable monomer composition. Moreover, since the load to stirring becomes large, it is not preferable because the motor is enlarged and the capital investment is increased.

  In the preparation step, it is preferable to adjust the oxygen concentration in the preparation container by supplying a gas whose oxygen concentration is adjusted. Moreover, the gas supply method is not particularly limited, and may be supplied once or intermittently, or may be continuously performed. Furthermore, the method for supplying the gas into the preparation container is not particularly limited. Although it is common to supply directly to a gaseous-phase part, you may supply directly in a polymerizable monomer composition.

  The monomer composition is added in order to reduce the viscosity of a polymer necessary for the toner such as a plasticizer, a charge control agent, and a crosslinking agent, and other additives (for example, a polymer formed by a polymerization reaction). Organic solvents, polymer polymers, dispersants, etc.) may be added as appropriate.

  In the following specification, non-predetermined particles generated in the step of classifying the produced toner particles described later can be added to the polymerizable monomer composition. The predetermined outer particles may be added as they are, or may be added after kneading with a kneader or the like to lower the molecular weight.

  The polymerizable monomer composition obtained by the above steps is subsequently introduced into the following steps to obtain toner particles.

(Aqueous medium preparation process and polymerizable monomer composition dispersion / granulation process)
An aqueous medium containing a dispersion stabilizer is prepared and charged into a vertical stirring tank equipped with a stirrer having a high shearing force, and a polymerizable monomer composition is added and stirred to the polymerizable monomer. A dispersion of the composition is obtained. The shape of the high shearing stirring device and the stirring blade is not particularly limited, but the stirrer is Ultra Tarrax (manufactured by IKA), T.W. K. Homomixer (manufactured by Special Machine Industries), T. K. Commercially available stirrers having a high shearing force such as Filmix (manufactured by Tokushu Kika Kogyo Co., Ltd.) and Claremix (manufactured by M Technique Co., Ltd.) can be used.

(Polymerization process)
In the polymerization step in the present invention, a general stirring tank capable of adjusting the temperature can be used. The polymerization temperature is 40 ° C. or higher, generally 50 to 90 ° C. The polymerization temperature may be constant throughout, but may be raised in the latter half of the polymerization step for the purpose of obtaining a desired molecular weight distribution. In general, since the polymerization temperature is higher than the liquid temperature in the preparation process, the oxygen in the polymerizable monomer composition decreases with time, so the oxygen concentration in the gas phase in the polymerization process is not particularly limited. . When carried out under a nitrogen stream, the oxygen in the polymerizable monomer composition can be almost removed, and the influence of polymerization inhibition by oxygen from the middle to the end of the polymerization reaction becomes smaller, and the ratio of the residual monomer is reduced. Can do.

(Purification process)
(Solid-liquid separation process, washing process and drying process)
In order to remove volatile impurities such as unreacted monomers and by-products, a part of the aqueous dispersion medium may be distilled off after completion of the polymerization. Distillation can be performed under normal pressure or reduced pressure. In order to remove the dispersion stabilizer attached to the surface of the polymer fine particles obtained by polymerizing the dispersed droplets, the polymer fine particle dispersion can be treated with an acid or an alkali. Thereafter, the polymer fine particles are separated from the liquid phase by a general solid-liquid separation method. However, in order to completely remove the acid or alkali and the dispersion stabilizer component dissolved therein, water is added again to remove the polymer fine particles. Wash. This washing process is repeated several times, and after sufficient washing, solid-liquid separation is performed again to obtain toner particles. The obtained toner particles are dried by a known drying means if necessary. Although heat can be applied as a drying means, usually a large amount of heat applied to the toner particles can affect the developability because the release agent and low molecular weight components contained in the toner particles are exposed. is there. However, since the toner particles according to the present invention have a sharp molecular weight distribution and can reduce low molecular weight components, if the drying temperature is 110 ° C. or less, the developability of the toner particles is not affected.

(Classification process)
The toner particles obtained in this way have a sufficiently sharp particle size as compared with conventional pulverized toners, but if a sharper particle size is required, classification can be performed by an air classifier or the like. It is also possible to remove particles that deviate from the particle size distribution as predetermined external particles.

  As the material of each member constituting the apparatus used in each of the above-described processes, a commonly used material such as stainless steel, glass, FRP, ceramic can be used. In addition, these surfaces may be subjected to treatments such as electrolytic polishing, fluororesin coating, and glass lining. The toner obtained by the production method of the present invention may be composed only of toner particles obtained by the polymerization method described above, or obtained by externally adding other additives to the toner particles as necessary. It may be. The toner particles and carrier may be mixed to form a two-component toner.

[monomer]
As a monomer suitably used in the present invention, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl monomer, a monofunctional monomer or a polyfunctional monomer can be used. Monofunctional monomers include styrene, α-methyl styrene, β-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert. -Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, etc. Styrene derivatives; 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 Acrylic monomers such as octyl acrylate, n-nonyl 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 , Diethyl phosphate ethyl methacrylate Methacrylic monomers such as dibutyl phosphate ethyl methacrylate; vinyl esters such as methylene aliphatic monocarboxylic acid ester, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether, vinyl ethyl ether, And vinyl ethers such as vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone.

  As polyfunctional monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene Glycol diacrylate, 2,2′-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, Tetraethylene glycol dimethacrylate, polyethylene glycol dimethyl Chlorate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxydiethoxy) phenyl) propane, 2,2′-bis (4- (methacryloxypolyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether and the like can be mentioned. In the present invention, the above monofunctional monomers are used singly or in combination of two or more, or the above monofunctional monomers and polyfunctional monomers are used in combination. Among the above-described monomers, styrene or a styrene derivative is preferably used alone or in combination, or in combination with other monomers from the viewpoint of toner development characteristics and durability.

[Colorant]
Examples of the colorant used in the present invention include carbon black, iron black, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6, yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, tartrazine lake, molybdenum orange, permanent orange GTR, benzidine orange G, cadmium red, Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Bitumen, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Quinacridone, Rhodamine Lake, Phthalocyanine Blue, Fast Sky Blue, Pigment Green B, Examples of the pigment include malachite green lake and final yellow green G.

  In selecting a colorant, it is necessary to pay attention to the polymerization inhibitory property and water phase transferability of the colorant. In particular, since dyes and carbon black often have polymerization inhibiting properties, care must be taken when using them. Preferably, these should be subjected to surface modification, for example, a hydrophobic treatment with a substance that does not inhibit polymerization. Examples of the method for surface-treating the dye include a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is added to the polymerizable monomer composition. In addition to carbon black, the carbon black may be grafted with a substance that reacts with the surface functional groups of the carbon black, such as polyorganosiloxane.

[Release agent]
As a release agent used in the present invention, a wax in a solid state at room temperature may be used in terms of toner blocking resistance, durability of a large number of sheets, low-temperature fixability, and offset resistance.

  Examples of the wax include polymethylene wax such as paraffin wax, polyolefin wax, microcrystalline wax and Fischer-Tropsch wax, amide wax, higher fatty acid, long chain alcohol, ester wax, and derivatives such as graft compounds and block compounds thereof. These are preferably removed from the low molecular weight component and have a sharp maximum endothermic peak in the endothermic curve obtained by a differential scanning calorimeter. In order to improve the translucency of the image fixed on the OHP, a linear ester wax is particularly preferably used. The linear ester wax may be contained in an amount of 1 to 40 parts by weight, more preferably 4 to 30 parts by weight, based on 100 parts by weight of the monomer.

  In the present invention, a second release agent having a melting point lower than 80 ° C. can be used in combination in order to increase the plasticity of the toner particles and improve the fixability in the low temperature region. As the second release agent, a linear alkyl alcohol having 15 to 100 carbon atoms, a linear fatty acid, a linear acid amide, a linear ester or a montan derivative wax is preferably used. It is more preferable that impurities such as liquid fatty acid have been previously removed from these waxes.

[Charge control agent]
The toner produced according to the present invention may contain a charge control agent. Known charge control agents can be used. For example, organic metal compounds and chelate compounds are effective for controlling the toner to be negatively charged, and monoazo dye metal compounds, acetylacetone metal compounds, aromatic hydroxy compounds. Examples include carboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides, esters, and phenol derivatives such as bisphenol. Urea derivatives, metal-containing salicylic acid compounds, quaternary ammonium salts, calixarene, silicon compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-acrylic-sulfonic acid copolymers, non-metals Examples thereof include carboxylic acid compounds.

  Examples of toners that are controlled to be positively charged include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, And onium salts such as phosphonium salts thereof and their lake pigments, triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid) , Lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, dibutyltin borate Dioctyl tin borate, include diorgano tin borate such as dicyclohexyl tin borate, may be used in combination alone, or two or more kinds. Among these, a charge control agent such as a nigrosine-based quaternary ammonium salt is particularly preferably used.

  These charge control agents are used in an amount of 0.01 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the monomer.

[Polymerization initiator]
Examples of the polymerization initiator that can be used in the present invention include azo polymerization initiators. As azo polymerization initiators, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobismethylbutyronitrile, and the like.

  An organic peroxide initiator can also be used. Organic peroxide initiators include benzoyl peroxide, lauroyl peroxide, di-α-cumyl peroxide, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, bis (4-t-butyl) (Cyclohexyl) peroxydicarbonate, 1,1-bis (t-butylperoxy) cyclododecane, t-butylperoxymaleic acid, bis (t-butylperoxy) isophthalate, methyl ethyl ketone peroxide, tert-butylperoxy Examples include 2-ethylhexanoate, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and the like.

  A redox initiator in which an oxidizing substance and a reducing substance are combined can also be used. Examples of the oxidizing substance include inorganic peroxides such as hydrogen peroxide and persulfates (sodium salts, potassium salts, ammonium salts, etc.), and oxidizing metal salts such as tetravalent cerium salts. Reducing substances include reducing metal salts (divalent iron salts, monovalent copper salts, trivalent chromium salts, etc.), ammonia, and lower amines (amines having about 1 to 6 carbon atoms such as methylamine and ethylamine). Amino compounds such as hydroxylamine, sodium thiosulfate, sodium hydrosulfite, sodium hydrogen sulfite, sodium sulfite, sodium formaldehyde sulfoxylate and other reducing sulfur compounds, lower alcohols (about 1 to 6 carbon atoms), ascorbic acid or Examples thereof include salts thereof and lower aldehydes (having about 1 to 6 carbon atoms). The initiator is selected with reference to the 10-hour half-life temperature, and is used alone or in combination. The addition amount of the polymerization initiator varies depending on the desired degree of polymerization, but generally 0.5 to 20 parts by mass is added to 100 parts by mass of the monomer.

[Crosslinking agent]
Various cross-linking agents can also be used in the present invention. Examples of the crosslinking agent include divinylbenzene, 4,4′-divinylbiphenyl, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, glycidyl (meth) acrylate, and trimethylolpropane tri (meth) acrylate. Mention may be made of functional compounds.

[Distributed media]
The dispersion medium may be any known medium used in various polymerization methods, and is appropriately selected depending on the monomer used, the polymerization method, and the like, and is not particularly limited. In suspension polymerization, an aqueous medium is used.

[Dispersion stabilizer]
As a dispersion stabilizer for satisfactorily dispersing toner raw materials in an aqueous medium, for example, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, which are inorganic compounds , Magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, titania and the like. Examples of the organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like. The dispersion stabilizer is preferably used in an amount of 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the monomer.

  Commercially available dispersion stabilizers may be used as they are, but when using the above-mentioned inorganic compound, in order to obtain dispersed particles having a fine uniform particle size, the inorganic compound is generated under stirring in a dispersion medium. You can also. For example, in the case of tricalcium phosphate, a dispersion stabilizer suitable for the suspension polymerization method can be obtained by introducing and mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution into sufficiently stirred water.

[Polar resin]
In the case of a polymerization method using an aqueous medium such as suspension polymerization, the inclusion of a release agent can be promoted by adding a polar resin to the toner raw material. When a polar resin is present in the toner raw material suspended in an aqueous medium, the polar resin tends to move near the interface between the aqueous medium and the toner raw material due to the difference in affinity for water, so the polar resin is unevenly distributed on the toner surface. Will do. As a result, the toner particles have a core-shell structure, and the inclusion property of the release agent is improved even when a large amount of the release agent is contained.

  As such a polar resin, a saturated or unsaturated polyester resin is particularly preferable because the fluidity of the polar resin itself can be expected when it is unevenly distributed on the toner surface to form a shell.

  As the polyester-based resin, those obtained by condensation polymerization of the following acid component monomers and alcohol component monomers can be used. Acid monomers include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, camphoric acid , Cyclohexanedicarboxylic acid, trimellitic acid and the like. As alcohol component monomers, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-bis (hydroxymethyl) Examples include alkylene glycols such as cyclohexane and polyalkylene glycols, bisphenol A, hydrogenated bisphenol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin, trimethylolpropane, pentaerythritol, and the like.

[External additive]
In the production method of the present invention, an external additive can be used 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 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, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, and zinc oxide, nitrides such as silicon nitride, and carbides such as carbide silicon carbide. Inorganic metal salts such as calcium sulfate, barium sulfate and calcium carbonate, fatty acid metal salts such as zinc stearate and calcium stearate, carbon black, silica and the like are used.

  These external additives are used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of toner particles. The external additives may be used singly or in combination of two or more, but those subjected to hydrophobic treatment are more preferable. Furthermore, the production method of the present invention can also be applied to a production method of a magnetic toner containing a magnetic material.

[Magnetic material]
The magnetic material contained in the toner can also serve as a colorant. In the present invention, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, hematite and ferrite, metals such as iron, cobalt and nickel, or these metals and aluminum, cobalt, copper, lead, magnesium, tin, Examples thereof include alloys of metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof.

These magnetic materials have an average particle diameter of 2 μm or less, preferably about 0.1 to 0.5 μm. The content of the magnetic substance in the toner is about 20 to 200 parts by mass, particularly preferably 40 to 150 parts by mass with respect to 100 parts by mass of the monomer. In addition, the magnetic properties of the magnetic material when 800 kA / m is applied are as follows: coercive force (Hc) 1.6 to 24 kA / m, saturation magnetization (σs) 50 to 200 Am ² / kg, residual magnetization (σr) 2 to 20 Am ^2. / Kg is preferred.

[Hydrophobic agent]
In order to improve the dispersibility of these magnetic materials in the toner particles, it is also preferable to subject the surface of the magnetic material to a hydrophobic treatment. For the hydrophobization treatment, coupling agents such as a silane coupling agent and a titanium coupling agent are used. Among them, a silane coupling agent is preferably used, and a general formula RmSiYn [wherein R represents an alkoxy group, m Represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, vinyl group, glycidoxy group, or methacryl group, and n represents an integer of 1 to 3. ]. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyl Diethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxy Silane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, n-butyltrimethoxysilane, isobutyl Le trimethoxysilane, trimethyl methoxysilane, hydroxypropyl Ritori silane, n- hexadecyl trimethoxy silane, can be mentioned n- octadecyl trimethoxysilane.

  The toner according to the present invention has a finer particle diameter, more specifically, a weight average diameter of 4 measured by a Coulter counter in order to faithfully reproduce finer latent image dots in response to a demand for higher image quality. A toner having a coefficient of variation in number of 10 to 10 μm and 25% or less is most preferable. When the toner is less than 4 μm, a large amount of untransferred toner is generated on the photosensitive member or the intermediate transfer member due to poor transfer efficiency, which causes undesirable unevenness of the image due to fog and transfer failure. Further, when the weight average diameter of the toner exceeds 10 μm, fusion to the member is likely to occur. When the number variation coefficient of the toner exceeds 25%, these tendencies become stronger and become a problem.

  In order to reduce the toner adhesion to the non-image area on the electrostatic image bearing member and the amount of residual toner, it is necessary that the chargeability of the toner particles is sufficient and uniform. Furthermore, when using a toner having a small particle diameter from the viewpoint of improving the image quality, the adhesion force of the toner particles increases, so the shape of the toner particles has a great influence on the toner adhesion to the non-image area on the electrostatic charge image carrier. Effect. In other words, the closer the toner particles are to a spherical shape and the more uniform the shape, the smaller the adhesion area of the particles, the less toner adhesion to the non-image area on the electrostatic image bearing member and the remaining amount of transfer residual toner, high image quality and durability Stability is possible.

  The toner produced according to the present invention can be used as either a one-component or two-component developer.

  In the case of a magnetic toner containing a magnetic material in the toner as a one-component developer, a method of transporting or charging the magnetic toner using a magnet built in the developing sleeve is used. When non-magnetic toner containing no magnetic material is used, there is a method in which a blade and a fur brush are used to forcibly frictionally charge with a developing sleeve and the toner is attached to the sleeve to be conveyed.

  When the toner obtained by the production method of the present invention is used as a two-component developer, a carrier is used with the toner as a developer. Although it does not specifically limit as a carrier used for this invention, It is comprised by the single or composite ferrite state which mainly consists of iron, copper, zinc, nickel, cobalt, manganese, and a chromium atom.

  The average particle size of these carriers is preferably 10 to 100 μm, more preferably 20 to 50 μm.

  When the two-component developer is prepared, the mixing ratio between the carrier and the toner in the present invention is usually 2 to 15% by weight, preferably 4 to 13% by weight as the toner concentration in the developer. Is obtained. If the toner concentration is less than 2% by mass, the image density is low and impractical, and if it exceeds 15% by mass, fogging and in-machine scattering increase, resulting in image deterioration and increased developer consumption.

  EXAMPLES Hereinafter, although an Example, a comparative example, and a reference example are given and this invention is demonstrated more concretely, this invention is not limited at all by these. In the examples, the following method was used to measure the particle size distribution of the toner.

(1) Measurement of weight average particle diameter (D4) of toner The average particle diameter and particle size distribution of toner particles can be measured by various methods such as Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Co.). . In the present invention, a Coulter Multisizer (manufactured by Coulter Inc.) is used, and an interface (manufactured by Nikka) and a PC 9801 personal computer (manufactured by NEC) are connected to output the number distribution and volume distribution. Prepare a 1% NaCl aqueous solution. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume distribution is measured by measuring the volume and number of toner particles of 2 μm or more using the 100 μm aperture as the aperture by the Coulter Multisizer. And the number distribution were calculated.

  Then, the volume-based weight average particle diameter obtained from the volume distribution according to the present invention (D4: the median value of each channel is a representative value of the channel) and the number-based length average particle diameter obtained from the number distribution (D1). ) And the number variation coefficient.

(2) Number variation coefficient Number variation coefficient is: number variation coefficient = number standard deviation / number average particle diameter × 100
Indicated by That is, the smaller the coefficient of variation, the sharper the particle size distribution of the toner particles, and a larger value indicates a broader particle size distribution.

(3) Dissolved oxygen concentration S for the saturated dissolved oxygen concentration S ₀ of dissolved oxygen concentration S / saturation measurement polymerizable monomer composition in the dissolved oxygen concentration S _0, the dissolved oxygen meter SG6 (manufactured by Mettler-Toledo International Inc.) using Measured. The polymerizable monomer composition was heated to 60 ° C., and the inside of the container was purged with oxygen and stirred for 5 minutes. A dissolved oxygen sensor was placed in the polymerizable monomer composition, and the dissolved oxygen concentration measured at this time was defined as a saturated dissolved oxygen concentration S ₀ . The dissolved oxygen concentration S of the polymerizable monomer composition obtained by the preparation process was measured using a dissolved oxygen meter SG6 (manufactured by METTLER TOLEDO). From the measured saturated dissolved oxygen concentration S ₀ and the dissolved oxygen concentration S, the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ was determined.

(4) Viscosity measurement of polymerizable monomer composition The viscosity of the polymerizable monomer composition was a Bisco Tester VT550 type (manufactured by Harke), which is a rotary viscometer. A circulating thermostat DC5-K20 was connected to a Viscotester VT550 type (manufactured by Harke), and the measurement temperature was set to 60 ° C. As a measuring method, 7 cm ³ of the polymerizable monomer composition was put in an NV cup (made by Harke), and an NV rotor (made by Harke) was further put in a Viscotester VT550 type. The viscosity was measured from the shear stress when the shear rate was 1.0 × 10 ³ (s ⁻¹ ) in the CR mode.

<Example 1>
Toner particles composed of polymer fine particles were produced by the following procedure.

[Polymerizable monomer composition dispersion preparation step]
(Preparation of polysynthetic monomer containing colorant (dispersion process))
Styrene monomer 72.0 parts by mass n-butyl acrylate monomer 28.0 parts by mass Silane coupling-treated magnetite 90.0 parts by mass Saturated polyester resin 5.0 parts by mass (Propylene oxide modified bisphenol A and isophthalic acid Polycondensate; Mn = 11,000, Mw / Mn = 2.4,
Acid value = 30 mgKOH / g, Tg = 72 ° C.)
Negative charge control agent 1.5 parts by mass (monoazo iron complex, T-77 (Hodogaya Chemical Co., Ltd.))
The above components were put into a preparation container and stirred at room temperature for 30 minutes.
(Preparation of polymerizable monomer composition (preparation process))
Polyethylene wax 12.0 parts by mass (maximum endothermic peak 65 ° C. in DSC,
Endothermic peak half-value width 17 ° C)

A gas whose oxygen concentration was adjusted to 6% was blown into the preparation vessel gas phase portion for 5 seconds every 60 seconds to make the oxygen concentration in the gas phase portion 6%. The colorant-containing polysynthetic monomer obtained by the dispersing step is heated to 60 ° C., and polyethylene wax is added thereto, and stirring is continued for 30 minutes at a peripheral speed of the stirring blade of 10.0 m / s. It was. The obtained polymerizable monomer composition had a dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ at 60 ° C. of 0.61 and a viscosity of 8 mPa · s.

(Aqueous medium preparation process)
Water 97.8 parts by weight Na ₃ PO ₄ 1.2 parts by weight 10% hydrochloric acid aqueous solution 0.3 parts by weight The above components are charged into another temperature-adjustable stirring tank and the temperature is raised to 60 ° C. while Na ₃ PO is being heated. Stir until ₄ is completely dissolved.

A solution prepared by dissolving 0.7 parts by mass of CaCl _{2 in} 5 parts by mass of water was added thereto, and the mixture was kept at 60 ° C. at a peripheral speed of 20.0 m / s for 30 minutes using CLEARMIX (manufactured by M Technique). By stirring, an aqueous medium that is an aqueous suspension of Ca ₃ (PO ₄ ) ₂ fine particles was obtained.

(Polymerizable monomer composition dispersion step)
The peripheral speed of Claremix (M Technique Co., Ltd.) was set to 30.0 m / s, and the polymerizable monomer composition was charged into the stirring tank while maintaining the liquid temperature of the aqueous medium at 60 ° C. Stirring is carried out at 0.0 m / s, and after 2 minutes from the start of stirring, 7.0 parts of a polymerization initiator t-butylperoxypivalate is added, and stirring is continued for another 11 minutes to thereby disperse the polymerizable monomer composition. Got.

[Polymerization process]
The polymerizable monomer composition dispersion obtained by the above steps is transferred into a stirrer vessel equipped with a propeller stirring blade, and the temperature of the solution is raised to 90 ° C. under a nitrogen stream and stirred for 4 hours. Polymerization was performed to obtain a polymer fine particle dispersion.

[Purification process] (Solid-liquid separation process, washing process, drying process, classification process)
After completion of the polymerization reaction, the residual monomer was distilled off under reduced pressure, and after cooling, hydrochloric acid was added to the resulting polymer fine particle dispersion and stirred to form Ca ₃ (PO ₄ ) ₂ fine particles covering the polymer fine particles. Was dissolved in a pressure filter, water was added thereto to make a dispersion again, and then the liquid was again removed with the pressure filter. After repeating this operation until Ca ₃ (PO ₄ ) ₂ is sufficiently removed, the polymer particles finally solid-liquid separated are dried at a drying temperature of 110 ° C. using an airflow drying device. And toner particles were obtained by classification.

[Evaluation]
The particle size distribution of the dried toner particles was measured, the number variation coefficient was calculated and evaluated according to the following evaluation criteria, and the evaluation results are shown in Table 1.

[Image output test]
Under a normal temperature and humidity environment (23 ° C., 60% RH), the following image forming apparatus was used to perform an image printing test of 2000 sheets in an intermittent mode with an image pattern having an A-point of 8 points and a printing rate of 4%. went. As the transfer material, A4 75 g / m ² paper was used. Hydrophobic silica fine powder having 100 parts by mass of the obtained toner particles 1 and silica having a number average primary particle size of 12 nm treated with hexamethyldisilazane and then with silicone oil, and a BET value after treatment of 120 m ² / g 1.0 part by mass of the toner was mixed with a Henschel mixer (Mitsui Miike Chemical Co., Ltd.) to obtain a toner having a weight average particle diameter of 6.5 μm. As an image forming apparatus, LBP-1210 (manufactured by Canon) was modified, and an image output test was performed under the following conditions.

  A rubber roller charger in which conductive carbon is dispersed as a primary charging roller as a charging member and coated with nylon resin is brought into contact with the photoreceptor (electrostatic latent image carrier) (contact pressure 40 g / cm), and a direct current voltage is applied. A bias in which an alternating voltage of 1.2 kVpp is superimposed on −620 V is applied to uniformly charge the photosensitive member. Subsequent to charging, the image portion is exposed with laser light (exposure light) to form an electrostatic latent image (dark portion potential Vd is −600 V and light portion potential VL is −120 V).

  The gap between the photosensitive member and the developing sleeve (toner carrier) is 270 μm. The magnetic toner carrier is a 12 mm diameter aluminum cylinder blasted on its surface. The layer thickness is about 7 μm and the JIS centerline average roughness is as follows. (Ra) A developing sleeve formed with a 1.2 μm resin layer was used. The developing sleeve contained a magnet roller having a developing magnetic flux density of 750 gauss. As the toner regulating member, a urethane blade having a thickness of 1.0 mm and a free length of 0.50 mm was used, and was brought into contact with the developing sleeve at a linear pressure of 19.6 N / m (20 g / cm).

・ Phenolic resin 100 parts by mass ・ Graphite (particle size: about 7 μm) 90 parts by mass ・ Carbon black 10 parts by mass

  Next, an alternating electric field as a developing bias was set to 1.6 kVpp, a frequency of 2200 Hz, and a DC voltage (Vdc) so that the latent image could be developed faithfully (a 200 μm 4-dot line latent image was developed to 200 μm). In Example 1, specifically, −420 V).

Under this condition, the obtained toner was used, and an image of 2000 points in continuous mode was used in an image in which the printing rate was 4% using an 8-point A letter in a normal temperature and humidity environment (23 ° C., 60% RH). I started painting. In all the evaluations, A4 75 g / m ² paper was used as the recording medium.

<Image density>
A solid image was formed at the initial stage (50th sheet) and after 2000 sheets (after endurance) in this image printing test. The image density of this solid image was measured with a Macbeth reflection densitometer (manufactured by Macbeth).

<Fog>
A white image was output and the fog on paper was measured and judged according to the following criteria. In addition, the measurement of fog was performed using a REFECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku Co., Ltd. The filter was a green filter, and the fog was calculated from the following formula (1).
Formula (1) Fog (reflectance) (%) = reflectance of standard paper (%) − reflectance of sample non-image part (%)

The determination criteria for fogging are as follows.
A: Very good (less than 1.5%)
B: Good (1.5% or more, less than 2.5%)
C: Normal (2.5% or more and less than 4.0%)
D: Poor (4% or more)

[Fixing test]
Using a device similar to the image forming device used in the image output test, the set temperature (fixing temperature) of the fixing device is increased from 130 ° C. to 230 ° C. every 5 ° C., and at each fixing temperature, FOX RIVER. A halftone image was formed on BOND paper (manufactured by Fox River, 90 g / m ² ) so that the image density was 0.80 to 0.85, and a fixed image was obtained.

The image obtained at each fixing temperature is rubbed 10 times with sylbon paper applied with a load of 4.9 kPa (50 g / cm ² ), and the fixing temperature when the density reduction rate before and after rubbing becomes 10% or less. This was taken as the fixing start temperature.

[Offset test]
Using a device similar to the image forming apparatus used in the image output test, the set temperature (fixing temperature) of the fixing device is increased from 130 ° C. to 230 ° C. every 5 ° C., and at each fixing temperature A4 A solid image was formed on 75 g / m ² paper so that the toner amount per unit area was 0.6 mg / cm ² . The formed solid image was observed to examine the temperature at which the high temperature offset phenomenon occurs (high temperature offset temperature). The presence or absence of the high temperature offset phenomenon was judged by visually observing stains on the image and the back of the paper.

<Example 2>
In the preparation step, a gas whose oxygen concentration is adjusted to 1% is blown into the preparation container gas phase for 60 seconds, the oxygen concentration in the gas phase is 1%, and the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ is 0.43. Except for the above, toner particles were obtained in the same manner as in Example 1. The viscosity of the polymerizable monomer composition was 10 mPa · s.

  Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 3>
In the preparation process, a gas whose oxygen concentration is adjusted to 15% is continuously blown into the gas phase part of the preparation vessel, the oxygen concentration in the gas phase part is set to 15%, and the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ is 0.69. Except for the above, toner particles were obtained in the same manner as in Example 1. The viscosity of the polymerizable monomer composition was 7 mPa · s.

  Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 4>
In the preparation step, a gas having an oxygen concentration of 4% was blown in, the oxygen concentration in the gas phase portion of the preparation vessel was set to 4%, the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ was 0.30, and the circumference of the stirring blade in the preparation step Toner particles were obtained in the same manner as in Example 1 except that the speed was 7.0 m / s. The viscosity of the polymerizable monomer composition was 11 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 5>
In the preparation step, a gas having an oxygen concentration of 10% is blown in, the oxygen concentration in the gas phase portion of the preparation vessel is set to 10%, the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ is 0.78, and the peripheral speed of the stirring blade is 15 Toner particles were obtained in the same manner as in Example 1 except for 0.0 m / s. The viscosity of the polymerizable monomer composition was 5 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 6>
Toner particles were obtained in the same manner as in Example 1 except that the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ in the preparation step was 0.52, and the peripheral speed of the stirring blade was 2.0 m / s. The viscosity of the polymerizable monomer composition was 9 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 7>
Toner particles were obtained in the same manner as in Example 1 except that the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ in the preparation step was 0.65 and the peripheral speed of the stirring blade was 20.0 m / s. The viscosity of the polymerizable monomer composition was 7 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 8>
In the preparation process, 15.1 parts by mass of the fine powder and the coarse powder selected in the classification process of Examples 1 to 7 were added together, and the dissolved oxygen concentration S / saturation at a liquid temperature of 60 ° C. of the polymerizable monomer composition was added. Toner particles were obtained in the same manner as in Example 1 except that the dissolved oxygen concentration S ₀ was 0.49 and the viscosity of the polymerizable monomer composition was 97 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 9>
A gas with an oxygen concentration of 4% was blown in the preparation process, the oxygen concentration in the gas phase part of the preparation container was 4%, the peripheral speed of the stirring blade was 1.0 m / s, and the fine powder and the coarse powder were combined in the preparation process. Toner particles were obtained in the same manner as in Example 8 except that 21.6 parts by mass were added. Table 1 shows the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ and the viscosity of the polymerizable monomer composition. Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 10>
Toner particles were obtained in the same manner as in Example 9 except that in the preparation step, a gas having an oxygen concentration of 10% was blown and the oxygen concentration in the gas phase portion of the preparation container was changed to 10%. Table 1 shows the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ and the viscosity of the polymerizable monomer composition. Table 1 shows the result of image evaluation similar to that in Example 1.

<Example 11>
After adding 450 parts by mass of 0.1M Na ₃ PO ₄ aqueous solution to 400 parts by mass of ion-exchanged water and heating to 60 ° C., the peripheral speed is 20.0 m / m using Claremix (M Technique Co., Ltd.). Stir at s. To this, 68 parts by mass of 1.0 M CaCl ₂ aqueous solution was added to obtain an aqueous medium containing calcium phosphate.

On the other hand, as a preparation process,
Styrene 83 parts by mass n-butyl acrylate 17 parts by mass C.I. I. Pigment Blue 15: 3 5 parts by mass Saturated polyester resin 5.0 parts by mass (Polycondensation product of propylene oxide-modified bisphenol A and isophthalic acid; Mn = 11,000, Mw / Mn = 2.4,
Acid value = 30 mgKOH / g, Tg = 72 ° C.)
Aluminum compound of dialkyl salicylic acid 1.0 part by mass Hydrocarbon wax 3 parts by mass (endothermic peak = 80 ° C., half width = 8, Mw = 750)
9 parts by weight of ester wax (endothermic peak = 67 ° C., half width = 4, Mw = 690)
Divinylbenzene 0.05 part by mass A gas adjusted to an oxygen concentration of 6% was blown into the adjustment vessel in which the oxygen concentration in the gas phase part was 6%, and the mixture was heated to 60 ° C. The mixture was stirred and dissolved / dispersed at 0 m / s for 30 minutes. In this, 3.5 mass parts of polymerization initiators 2,2′-azobis (2,4-dimethylvaleronitrile) were dissolved to prepare a polymerizable monomer composition. Table 1 shows the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ and the viscosity of the polymerizable monomer composition.

The polymerizable monomer composition is charged into the aqueous medium, and the mixture is stirred for 11 minutes at a peripheral speed of 30.0 m / s with Claremix (manufactured by M Technique) in an N ₂ atmosphere at 60 ° C. A dispersion of a functional monomer composition was obtained.

  Then, while heating to 90 ° C. and stirring with a paddle stirring blade, when the polymerization conversion rate of the polymerizable vinyl monomer reached 90%, an aqueous 0.1 mol / liter sodium hydroxide solution was added to disperse in water The pH of the medium was adjusted to 8. Furthermore, it heated up at 80 degreeC with the temperature increase rate of 40 degreeC / Hr, and was made to react for 4 hours. After completion of the polymerization reaction, the remaining monomer was distilled off under reduced pressure. After cooling, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 6 hours to dissolve the calcium phosphate salt. After filtration and washing with water, the toner particles were obtained by drying at a drying temperature of 110 ° C. using an airflow dryer. The particle size distribution of the obtained toner particles was measured to calculate the number variation coefficient.

  1.0 part by mass of hydrophobic silica fine powder (number average primary particle diameter 7 nm) surface-treated with hexamethylene disilazane, 0.15 rutile type titanium oxide fine powder with respect to 100 parts by mass of the toner particles. A toner was obtained by dry-mixing 5 parts by mass (number average primary particle diameter 45 nm) and 0.5 part by mass of rutile-type titanium oxide fine powder (number average primary particle diameter 200 nm) with a Henschel mixer (Mitsui Mining Co., Ltd.) for 5 minutes. .

[Image output test]
The obtained toner particles were evaluated according to the following evaluation, and the evaluation results are shown in Table 1.

<Image density>
As an evaluation machine, LBP-2510 (manufactured by Canon Inc.) was used, and image evaluation was performed in a normal temperature and normal humidity environment (23 ° C., 60% RH).

  In the evaluation, 190 g of each toner shown in Table 2 was filled in the cartridge and mounted in a station of the toner color, and a dummy cartridge was mounted in the other station, and a single color evaluation was performed.

Images were printed at the initial stage and at the end of the durability evaluation in an image printing test in which up to 5,000 images with a printing rate of 2% were printed using ordinary copying machine plain paper (75 g / m ² ). A solid image was output and evaluated by measuring its density. The image density was measured by using a “Macbeth reflection densitometer RD918” (manufactured by Macbeth Co., Ltd.) to measure the relative density with respect to an image of a white background portion having a document density of 0.00. Evaluation criteria are shown below.
・ Very good 1.40 or more ・ Good 1.35 or more, less than 1.40 ・ No problem in practical use 1.00 or more, less than 1.35 ・ Slightly difficult Less than 1.00

<Image fog>
LBP-2510 (manufactured by Canon Inc.) was used as an evaluation machine, and image evaluation was performed in a high temperature and high humidity environment (30 ° C., 80% RH) and a low temperature and low humidity environment (15 ° C., 10% RH). .

  In the evaluation, 190 g of each toner shown in Table 2 was filled in the cartridge and mounted in a station of the toner color, and a dummy cartridge was mounted in the other station, and a single color evaluation was performed.

In the image output test in which up to 10,000 images of a printing ratio of 2% are printed out using a transfer material of ordinary plain paper (75 g / m ² ) for a copying machine, “REFECTRECTER MODEL TC-6DS” is used. From the difference between the whiteness (reflectance Ds (%)) of the white portion of the printout image measured by “Tokyo Denshoku Co., Ltd.” and the whiteness of the transfer paper (average reflectance Dr (%)), the fog density ( %) (= Dr (%) − Ds (%)) was calculated, and the image fog at the end of the durability evaluation was evaluated. Amberlite was used as a filter in the case of cyan.
A: Very good Less than 0.5% B: Good 0.5% or more to less than 1.0% C: No problem in practical use 1.0% or more to less than 1.5% D: Somewhat difficult 1.5% that's all

[Fixing test]
Using a device similar to the image forming device used in the image output test, the set temperature (fixing temperature) of the fixing device is increased from 130 ° C. to 230 ° C. every 5 ° C., and at each fixing temperature, FOX RIVER. A halftone image was formed on BOND paper (manufactured by Fox River, 90 g / m ² ) so that the image density was 0.80 to 0.85, and a fixed image was obtained.

The image obtained at each fixing temperature is rubbed 10 times with sylbon paper applied with a load of 4.9 kPa (50 g / cm ² ), and the fixing temperature when the density reduction rate before and after rubbing becomes 10% or less. This was taken as the fixing start temperature.

[Offset test]
As an evaluation machine, LBP-2510 (manufactured by Canon Inc.) was used, and high temperature offset resistance was evaluated using Xx64g paper under normal temperature and normal humidity (23.5 ° C., 60% RH). After fifty sheets of solid white images were passed, double-sided copying was carried out on an image in which the entire area 5 cm from the leading edge was a halftone with an image density of 0.5, and the others were solid white. At this time, the level of the offset appearing on the white background portion was visually confirmed and evaluated according to the following evaluation criteria.
A: No offset is generated at all. B: An offset is generated slightly, but it is not at a level causing a problem in use. C: A slight offset is generated. Although it is at the level of actual use, it is not a problem in normal copying. D: Level that causes a problem in actual use because offset occurs in the entire longitudinal direction.

<Reference Example 1>
In the preparation step, a gas having an oxygen concentration of 0.1% is blown, the oxygen concentration in the gas phase portion of the preparation vessel is 0.1%, the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ is 0.13, and the polymerization temperature is 0.13. Toner particles were obtained in the same manner as in Example 1 except that the temperature was 70 ° C. and the drying temperature was 90 ° C. The viscosity of the polymerizable monomer composition was 6 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Reference Example 2>
In the preparation process, a gas having an oxygen concentration of 20% is blown, the oxygen concentration in the gas phase of the preparation container is set to 20%, the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ is 0.88, the polymerization temperature is 70 ° C., and the drying is performed. Toner particles were obtained in the same manner as in Example 1 except that the temperature was 90 ° C. The viscosity of the polymerizable monomer composition was 9 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Comparative Example 1>
A gas having an oxygen concentration of 0.1% was blown in the preparation step, the oxygen concentration in the gas phase portion of the preparation vessel was 0.1%, and the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ was 0.10. Toner particles were obtained in the same manner as in Example 9. The viscosity of the polymerizable monomer composition was 201 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Comparative example 2>
In the preparation step, a gas having an oxygen concentration of 20% was blown in, the oxygen concentration in the gas phase part of the preparation vessel was set to 20%, and the mixture was stirred at a peripheral speed of 24.0 m / s, and the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ was Toner particles were obtained in the same manner as in Example 9 except that the ratio was 0.91. The viscosity of the polymerizable monomer composition was 199 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 1.

<Comparative Example 3>
In the preparation step, a gas having an oxygen concentration of 0.1% was blown in, the oxygen concentration in the gas phase part of the preparation vessel was 0.1%, and the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ was 0.16. According to the same method as in Example 11, except that 19.6 parts by mass of the fine powder and coarse powder selected in the classification step of the same formulation as in Example 11 were added to the process and stirred at a peripheral speed of 24.0 m / s. Toner particles were obtained. The viscosity of the polymerizable monomer composition was 152 mPa · s. Table 1 shows the result of image evaluation similar to that in Example 11.

It is an example of the schematic of the preferable granulation apparatus used for the preparation process of this invention.

Explanation of symbols

1 Preparation Container 2 Motor 3 Oxygen Concentration Gas Inlet 4 Stirring Shaft 5 Gas Phase 7 Stirring Blade 8 Jacket

Claims (6)

A preparation step of mixing and / or dissolving an additive in a polymerizable monomer containing at least a colorant to obtain a polymerizable monomer composition containing the colorant and the additive, and the polymerizable monomer composition A granulation step of granulating the product into particles having a size corresponding to the particle size of the toner particles in an aqueous medium, and a polymerizable monomer in the polymerizable monomer composition granulated in the granulation step A method for producing toner particles having a polymerization step of obtaining toner particles by polymerizing
In the preparation step, the oxygen concentration C (vol%) of the gas phase portion of the preparation container containing the polymerizable monomer composition is set to 1 ≦ C ≦ 15.
A method for producing toner particles, wherein In the preparation step, the relationship between the saturated dissolved oxygen concentration S ₀ and the dissolved oxygen concentration S of the polymerizable monomer composition at the liquid temperature of the polymerizable monomer composition is 0.30 ≦ S / S ₀ ≦ 0.80
The method for producing toner particles according to claim 1, wherein:   The method for producing toner particles according to claim 1, wherein the preparation container is provided with a stirring blade, and the polymerizable monomer composition is stirred. The viscosity V (mPa · s) at the liquid temperature of the polymerizable monomer composition in the preparation step is as follows: V ≦ 100
Method for producing toner particles according to any one of claims 1 to 3, characterized by satisfying the. The method for producing toner particles according to any one of claims 1 to 4 , wherein the polymerizable monomer contains at least a hydrophobized magnetic substance. Method for producing toner particles according to any one of claims 1 to 5 polymerizable monomer is characterized by containing at least silane magnetic subjected to hydrophobic treatment with a coupling agent.

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