JP5350066B2 - toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which has excellent fixability at a low temperature and excellent heat resistant preservability and hardly brings about a blocking phenomenon even when used under a high-temperature environment. <P>SOLUTION: The toner includes toner particles constituted of core particles containing at least a binder resin, a colorant, and a wax and a coating layer formed by fixing fine resin particles on surfaces of the core particles, wherein the core particles furthermore contain a resin having a unit constituted of a nitrogen-containing vinyl monomer and a unit constituted of a vinyl monomer containing at least a carboxylic acid group and/or a sulfonic acid group or their alkyl ester groups. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a toner used to form a toner image by developing an electrostatic latent image formed by a method such as electrophotography, electrostatic recording, or toner jet recording.

  In recent years, printers and copiers are required to increase the resolution of images by digitization, and at the same time, increase the printing or copying speed, or save space and reduce power consumption by downsizing the apparatus. .

  In order to satisfy these requirements, improvement of the fixing performance of the toner itself is also required. That is, it is desired to realize a toner that can be fixed at a lower temperature.

  As a general method for improving the low-temperature fixability of the toner, a method of lowering the glass transition temperature of the binder resin constituting the toner is known. However, simply lowering the glass transition temperature decreases the heat-resistant storage stability of the toner, and when used in a high-temperature environment, the toner that agglomerates between the toners that come into contact with each other tends to cause a blocking phenomenon. Arise. Further, there is a problem that the toner carrying member is easily contaminated and the filming on the photosensitive member is likely to occur, resulting in a deterioration in image quality.

  In order to solve these problems, a toner having a capsule structure composed of core particles containing a resin having a low glass transition temperature and a coating layer containing a resin having a high glass transition temperature formed on the surface of the core particles has been devised. Has been.

  For example, a mixed liquid of a core constituent material containing a monomer (polymerizable monomer) that is a raw material of a thermoplastic resin and an outer shell constituent material containing amorphous polyester is dispersed in a dispersion medium. In addition, a capsule toner in which an outer shell (coating layer) is formed by an in-situ polymerization method in which the outer shell constituent material is unevenly distributed on the surface of the droplet as the core particles are formed by polymerization has been proposed (see Patent Document 1). .

  Further, by adding an aqueous dispersion of resin fine particles obtained by emulsion polymerization or soap-free emulsion polymerization to polymer particles (core particles) obtained by suspension polymerization, 95% or more of the surface of the polymer particles is obtained. There has been proposed a toner which is coated with fine particles and then heated to a temperature higher than the glass transition temperature of the polymer particles so as to have a surface substantially free of bulges (see Patent Document 2).

  In addition, fine particles obtained by phase inversion emulsification of an acidic group-containing resin in the presence of a basic neutralizing agent are mixed with an aqueous dispersion of resin particles (core particles), and an acid is added to the resin particle surface to add the particles. There has been proposed a toner obtained by precipitating fine particles, removing a liquid medium, and then stirring and mixing a dried powder under heating (see Patent Document 3).

  Further, an intermediate layer having a charging property opposite to that of the toner inner particle is formed on the surface of the toner inner particle (core particle), and a resin (resin fine particle) having a charging property opposite to that of the intermediate layer is formed on the surface of the intermediate layer. A toner in which an outer shell layer (coating layer) is formed is disclosed (see Patent Document 4).

  Among the above-described conventional examples, the toner disclosed in Patent Document 1 utilizes the property that separation occurs in the liquid droplets of the mixed liquid due to the difference in solubility index between the core material and the outer shell material. Thus, an outer shell is formed, and a layer having a substantially uniform thickness is formed. However, the heat-resistant storage stability of the toner having the outer shell formed in this way is not necessarily sufficient, and in the case of core particles having a low glass transition temperature that actually satisfies the low-temperature fixability, in order to obtain sufficient heat-resistant storage stability. It is necessary to add a large amount of amorphous polyester as the outer shell constituent material. As a result, since the viscosity of the droplets is remarkably increased during granulation, there is a problem that manufacturing stability is impaired.

  Further, the toner disclosed in Patent Document 2 described above has a sufficient mechanical strength because the surface thereof is smooth without any protrusion. However, when heating is performed excessively in order to obtain such a smooth surface, a part of the resin fine particles attached to the surface of the core particle may be buried inside the core particle. As a result, the core particles were partially exposed, or a part of the contained wax oozed out, so that sufficient heat-resistant storage stability could not be obtained. On the other hand, when heating is performed under milder conditions so as to avoid such problems, the smoothness of the surface is lowered and sufficient mechanical strength cannot be obtained. Peeling and falling off easily occurred, and sufficient heat resistant storage stability could not be obtained. In addition, it is difficult to obtain a stable triboelectric charge property with such a toner having poor surface smoothness.

  In addition, the toner disclosed in the above-mentioned Patent Document 3 adds an acid to the aqueous dispersion to return the acidic groups of the fine particles to an unneutralized state, thereby precipitating the fine particles on the surface of the core particles, thereby forming a resin fine particle layer. It is to be formed. However, in this method, the fine particles easily aggregate together, and the state of precipitation on the surface of the core particles is not necessarily uniform. In addition, since the fine particles that have been deposited may fall off due to filtration and drying without heat treatment, a toner having sufficient blocking resistance even when the powder thus obtained is stirred and mixed under heating. It was difficult to get. Further, since the smoothness of the toner surface is inferior, it is difficult to obtain a stable triboelectric chargeability.

  Further, the toner disclosed in Patent Document 4 described above is obtained by forming an intermediate layer by adhering inorganic fine particles such as tricalcium phosphate or organic fine particles such as benzoguanamine to a dispersion of core particles, The outer shell layer is formed by attaching fine particles. Such a toner production method is not only complicated in process, but particularly when inorganic fine particles are used as the intermediate layer, the fixing strength of each layer may not be sufficient, which may cause peeling or dropping, and sufficient blocking resistance. It was difficult to obtain a toner having the properties.

  As described above, in a toner having a capsule structure composed of core particles having a low glass transition temperature and a coating layer having a high glass transition temperature, it is very difficult to obtain a toner having both low temperature fixability and heat resistant storage stability. However, it is difficult to achieve this early.

Special registration 03030741 JP 2000-112174 A JP 2000-347455 A Japanese Patent Laid-Open No. 2003-091093

  An object of the present invention is to provide a toner that solves the above-described conventional problems.

  That is, an object of the present invention is to provide a toner having excellent low-temperature fixability, excellent heat-resistant storage stability, and hardly causing a blocking phenomenon even when used in a high-temperature environment.

The present invention provides a toner having a binder resin, a core particle containing a colorant and a wax scan, the toner particles composed of the coating layer formed by fixing the fine resin particles on the surface of the core particles, the (I) a nitrogen-containing vinyl monomer and (ii) a vinyl monomer containing a carboxylic acid group and / or a sulfonic acid group or an alkyl ester group thereof at the interface between the core particle and the coating layer. The present invention relates to a toner characterized in that at least a copolymer resin obtained by copolymerization is present.

  According to the present invention, it is possible to provide a toner having excellent low-temperature fixability, excellent heat-resistant storage stability, and hardly causing a blocking phenomenon even when used in a high-temperature environment.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

  In the capsule structure toner in which a coating layer of resin fine particles is provided on the surface of the colored particles serving as the core particles, the present inventors include a resin having a specific structure in the core particles, thereby It has been found that the adhesion can be improved.

  The resin having a specific structure means that at least a nitrogen-containing vinyl monomer and at least a vinyl monomer containing at least a carboxylic acid group and / or a sulfonic acid group or an alkyl ester group thereof are used. It is a resin obtained by polymerization.

  And it became clear that this makes it possible to form a coating layer that is homogeneous and excellent in mechanical strength, and has completed the present invention.

  Hereinafter, a nitrogen-containing vinyl monomer is referred to as a “nitrogen-containing monomer”, and a vinyl monomer containing a carboxylic acid group and / or a sulfonic acid group or an alkyl ester group thereof is referred to as an “acid / alkyl ester group-containing monomer”. May be described as a “mer”. Further, a unit composed of a nitrogen-containing vinyl monomer is referred to as a “nitrogen-containing unit”, and a unit composed of a vinyl monomer containing a carboxylic acid group and / or a sulfonic acid group or an alkyl ester group thereof. “Acid / alkyl ester group-containing unit” may be described.

  When the core particle of the toner of the present invention is produced in an aqueous medium, the resin is unevenly distributed on the surface of the core particle when the resin is contained. This is because the resin contains a unit derived from a highly polar acid / alkyl ester group-containing monomer. Thereafter, in the present invention, resin fine particles are fixed to the surface of the core particles in an aqueous medium to form a coating layer.

  The toner particles produced in this way have the above-mentioned resin at the interface between the core particles and the coating layer, so that the adhesion between the coating layer and the core particles is improved. Further, since the durability of the toner is improved, a blocking phenomenon in a high humidity environment can be prevented. In addition, an interface means the area | region where the core particle and the coating layer have joined.

  As a method for fixing the resin fine particles to the surface of the core particles, both particles are allowed to coexist in a state dispersed in an aqueous medium, and the pH of the aqueous medium is adjusted to control the dispersibility of the resin fine particles. A method of heat treatment is generally used after adhering to the surface of the particles. However, since the resin fine particles have a negative charge in water, when core particles having a negative surface charge are used in the same manner, an electric repulsive force acts between these particles to fix the uniform resin fine particles. Is disturbed.

  As a more preferable fixing method, the following method can be used. That is, after producing core particles in an aqueous medium in which a dispersion stabilizer is dispersed, resin fine particles are added to the aqueous medium, and the resin fine particles are once adhered via the dispersion stabilizer present on the surface of the core particles. Then, an acid is added under heating to dissolve and remove the dispersion stabilizer and fix it.

  As a specific method for producing the core particles, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is prepared, and a polymerizable monomer in an aqueous medium in which a dispersion stabilizer is dispersed. A method of polymerizing a polymerizable monomer after suspending a body composition and granulating is mentioned.

  As the dispersion stabilizer, a substance having a charge opposite to the surface charge of the core particles is used. Therefore, according to this method, the resin fine particles can be uniformly adhered by the electrical action of the dispersion stabilizer present on the surface of the core particles, and the dispersion stabilizer is dissolved from this state to be uniformly fixed. be able to. However, even in this method, since the electric binding force disappears when the dispersion stabilizer is dissolved, the adhesion between the core particles and the resin fine particles still depends on the surface charge of each particle. .

  In that respect, the core particle of the present invention contains a resin having a unit composed of a nitrogen-containing monomer and a unit composed of an acid / alkyl ester group-containing monomer. By having these units, the isoelectric point obtained from the zeta potential measurement can be shifted to the high pH side.

  Here, the zeta potential is an index representing the state of surface charge of particles in water. In the case of particles having a negative surface charge, when the pH is lowered, the value of the zeta potential approaches zero along with this, and eventually turns to a positive charge. The isoelectric point is indicated by the pH value when the zeta potential value is exactly 0 mV. Shifting the isoelectric point of the core particle to the high pH side with respect to the isoelectric point of the resin fine particle means that the surface of the core particle is lost in the process in which the electric binding force disappears due to the dissolution of the dispersion stabilizer. This means that the charge is controlled to turn positive before the surface charge of the resin fine particles. That is, in this process, an electric attractive force is newly generated between the core particle and the resin fine particle, and it is considered that the adhesion between the core particle and the resin fine particle can be improved.

  The shift of the isoelectric point to the high pH side is considered to be mainly due to the action of the nitrogen-containing unit in the resin segregated on the surface of the core particles, whereas the nitrogen-containing unit is a dispersion stabilizer in the granulation process. It has the property of inhibiting the adsorption to the droplets. For this reason, when a resin containing only a nitrogen-containing unit is used, the stability of the droplets may be impaired, and granulation may not be performed.

  Although the detailed mechanism of action is unknown, the coexistence of the acid / alkyl ester group-containing unit in the resin alleviates the inhibition of the dispersion stabilizer's adsorption to the droplets by the nitrogen-containing unit, and stably granulates. Can be done.

  In order to produce such core particles, a resin containing at least a nitrogen-containing unit and an acid / alkyl ester group-containing unit is dissolved in the polymerizable monomer composition in advance in the core particle manufacturing step. The method of performing suspension polymerization can be mentioned.

  According to this method, in the droplet obtained by suspending the polymerizable monomer composition in the aqueous medium, the resin moves to the surface layer of the droplet as the polymerization of the polymerizable monomer proceeds. In addition, since it segregates on the surface when the core particles are formed, a sufficient effect can be obtained even with a small amount of resin.

  The resin segregated on the surface of the core particles in this way acts as an intermediate layer for electrically attracting the resin fine particles in the resin fine particle fixing step, thereby forming a coating layer having excellent adhesion. It is thought that you can.

  As the resin fine particles, it is preferable to use resin fine particles composed of a resin having a functional group capable of developing self-dispersibility at least in water. Specific examples of functional groups that can exhibit self-dispersibility in water include functional groups such as carboxylic acid groups and sulfonic acid groups, or salts thereof.

  Hereinafter, a resin containing at least a nitrogen-containing unit and an acid / alkyl ester group-containing unit may be referred to as an “interlayer forming resin”.

  In the present invention, the content of the resin in the core particles is preferably in the range of 0.5 to 20.0% by mass. If the content of the resin is in such a range, a sufficient effect of shifting the isoelectric point of the core particles to the high pH side can be obtained, and various physical properties can be easily designed when converted into a toner. . The content of the resin is more preferably 1.0 to 10.0% by mass.

  The content of the nitrogen-containing unit in the resin is preferably 2.0 to 10.0% by mass. By controlling the content of the nitrogen-containing unit in such a range, the isoelectric point of the core particle can be suitably shifted while maintaining granulation stability.

  Further, all of the acid / alkyl ester group-containing units in the resin may be alkyl ester groups, but it is more preferable that a part of them is in an acid state in terms of improving granulation stability. A preferable acid value as the resin is 1.0 to 30.0 mgKOH / g.

  In the present invention, the glass transition temperature of the core particles is preferably 20 to 60 ° C. The glass transition temperature of the resin fine particles is preferably 10 to 50 ° C. higher than the glass transition temperature of the core particles.

  The glass transition temperature of the core particles is in the above range, and further, the difference in the glass transition temperature between the resin fine particles and the core particles is in the above range, so that an excellent low-temperature fixing is achieved while maintaining sufficient heat-resistant storage stability. Sex can be obtained.

  As described above, the present invention provides a capsule-structure toner in which a coating layer of resin fine particles is provided on the surface of colored particles serving as core particles, and the core particles contain a resin having a specific structure and segregate on the surface. It was made into the intermediate | middle layer. In this way, a toner having both low-temperature fixability and heat-resistant storage stability is realized.

  Therefore, the technology is different from the conventional toner based on the encapsulation technology based on the in-situ polymerization method and the encapsulation technology based on the fixing of the resin fine particles, and the object of the present invention is merely obtained by combining these technologies. Is difficult to achieve.

  As described above, according to the present invention, it is possible to realize a toner having excellent low-temperature fixability, excellent heat-resistant storage stability, and hardly causing a blocking phenomenon even when used in a high-temperature environment. Become.

  Here, the zeta potential of the core particles and the resin fine particles can be measured as follows using an ultrasonic zeta potential measuring device DT-1200 (manufactured by Dispersion Technology).

  First, pure water is prepared as a dispersion medium, and 0.5% by mass of core particles or resin fine particles are added thereto. At this time, if necessary, an appropriate amount of a nonionic surfactant that does not affect the zeta potential can be added. Next, after dispersing for 3 minutes using an ultrasonic disperser, stirring is performed while degassing for 10 minutes to obtain a dispersion of core particles or resin fine particles. About each dispersion liquid obtained in this way, a zeta potential is measured using the said apparatus. At this time, the pH of the dispersion is also measured.

  Next, an appropriate amount of a 1 mol / liter aqueous hydrochloric acid solution (if necessary, an aqueous 1 mol / liter potassium hydroxide solution) is added to the dispersion to adjust the pH of the dispersion to about 0.5, Similarly, the zeta potential is measured. Thereafter, this operation is repeated while sequentially changing the pH of the dispersion by about 0.5 until the zeta potential value turns positive.

  The pH and the zeta potential value thus obtained are plotted on a graph, and each plot is connected to create a pH-zeta potential curve. The isoelectric point is determined from the pH-zeta potential curve of the graph in which the pH value when the zeta potential is 0 mV is created.

  Moreover, the acid value of resin containing a nitrogen-containing unit and an acid (ester) group containing unit is calculated | required with the following method.

The basic operation is based on JISK-0070.
1) First, 0.5 to 2.0 g of the sample is precisely weighed in a 300 ml beaker, and the mass at this time is defined as Wg. When the functional group of the sample is in a salt state, a sample that has been returned to an acid state in advance is used.
2) To this, 150 ml of a mixed solution of toluene / ethanol (4/1) is added and dissolved.
3) Titrate with 0.1 mol / l KOH ethanol solution. The titration can be performed, for example, using automatic titration using a potentiometric titration measuring device AT-400 (winworkstation) manufactured by Kyoto Electronics Co., Ltd. and an ABP-410 electric burette.
4) The consumption of the KOH solution at this time is Sml. At the same time, a blank is measured, and the consumption of KOH at this time is defined as Bml.
5) Calculate the acid value according to the following formula. In the formula, f is a factor of KOH.
Acid value (mgKOH / g) = {(SB) × 0.1f × 56.1} / W
Further, the glass transition temperature of the core particles and the resin fine particles can be determined as follows using a differential scanning calorimeter (2920MDSC) manufactured by TA Instruments, for example.

  First, about 6 mg of a sample is precisely weighed in an aluminum pan, and an empty aluminum pan is prepared as a reference pan. In a nitrogen atmosphere, the measurement temperature range is 20 to 150 ° C., the temperature rising rate is 2 ° C./min, and the modulation amplitude is ± 0. Measurement is performed under the conditions of 6 ° C. and a frequency of once / minute.

  From the reversing heat flow curve at the time of temperature rise obtained by measurement, draw a tangent line between the endothermic curve and the baseline before and after the temperature rise, and find the midpoint of the straight line connecting the intersections of each tangent line. The glass transition temperature is assumed.

  The core particle in this invention can be manufactured as follows, for example with a suspension polymerization method.

  First, a resin containing at least a colorant, a wax, a nitrogen-containing unit as an intermediate layer forming resin, and an acid / alkyl ester group-containing unit is added to the polymerizable monomer that is the main constituent material of the core particle. Next, these are uniformly dissolved or dispersed using a disperser such as a homogenizer, ball mill, colloid mill, or ultrasonic disperser to prepare a polymerizable monomer composition. At this time, a chain transfer agent, a charge control agent, a plasticizer, and other additives (for example, a dispersant) can be appropriately added to the polymerizable monomer composition as necessary.

  Next, the polymerizable monomer composition is put into an aqueous medium containing a dispersion stabilizer prepared in advance and suspended using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser. And granulate.

  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. Further, it may be added during granulation or after completion of granulation, that is, immediately before starting the polymerization reaction. Moreover, it can also add in the state melt | dissolved in the polymerizable monomer and other solvent as needed.

  In the polymerization reaction, the granulated suspension is heated to a temperature of 50 to 90 ° C., the particles of the polymerizable monomer composition in the suspension maintain the particle state, and the particles float and settle. To avoid this, it is carried out with stirring.

  The said polymerization initiator decomposes | disassembles easily by heating and produces | generates a free radical (radical). The generated radical is added to the unsaturated bond of the polymerizable monomer to newly generate an adduct radical. The generated adduct radical is further added to the unsaturated bond of the polymerizable monomer. By repeating such an addition reaction in a chain, the polymerization reaction proceeds, and core particles containing the polymerizable monomer as a main constituent material are formed.

  The resin containing at least the nitrogen-containing unit and the acid / alkyl ester group-containing unit dissolved in the droplet of the polymerizable monomer composition (interlayer forming resin) is a surface of the droplet as the polymerization reaction proceeds. When it moves to the layer and core particles are formed, it segregates in layers on its surface.

  The resin layer thus formed on the surface of the core particles plays a role of forming a coating layer having excellent adhesion by electrically attracting the resin particles as an intermediate layer in the fixing step of the resin particles. .

  When the polymerization reaction is completed, the core particle dispersion is filtered by a known method, washed, and then dried or redispersed in water.

  Here, examples of the polymerizable monomer that can be used to obtain the binder resin that is the main constituent material of the core particles include the following.

  Styrene; α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert- Styrenes such as butyl styrene, pn-hexyl styrene, pn-octyl, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene Monomer: methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylic acid 2-chloroethyl, phenyl acrylate, acrylic acid-2-hydro Acrylic esters such as ethyl; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Methacrylic acid esters such as stearyl, phenyl methacrylate, 2-hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide.

  Among these polymerizable monomers, it is preferable to use a mixture of styrene or a styrene derivative and another polymerizable monomer from the viewpoint of developing characteristics and durability of the toner. The mixing ratio of these polymerizable monomers may be appropriately selected in consideration of the desired glass transition temperature of the core particles.

  In the production of the core particles, a small amount of a polyfunctional monomer can be used in combination for the purpose of improving high temperature offset resistance. As the polyfunctional monomer, a compound having two or more polymerizable double bonds is mainly used. Aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylate esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinylaniline, divinyl ether and divinyl Divinyl compounds such as sulfide and divinyl sulfone; compounds having three or more vinyl groups.

  These polyfunctional monomers are not necessarily used, but the preferred addition amount when used is 0.01 to 1 part by mass with respect to 100 parts by mass of the monofunctional polymerizable monomer. .

  Examples of the nitrogen-containing monomer that is a constituent material of the resin containing at least the nitrogen-containing unit and the acid / alkyl ester group-containing unit include the following.

  Aminoethyl acrylate, aminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, 4-vinylpyridine, 2-vinylpyridine, N, N-dimethylaminostyrene, methyl α-acetaminoacrylate, vinylimidazole, Amino group-containing vinyl monomers such as N-vinylpyrrole, N-vinylthiopyrrolidone, N-arylphenylenediamine, aminocarbazole, aminothiazole, aminoindole, aminopyrrole, aminoimidazole, aminomercaptothiazole; acrylamide, methacrylamide N-methylacrylamide, N-methylmethacrylamide, N-butylacrylamide, Acetone acrylamide, N-methylol acrylamide, N, N′-methylene-bisacrylamide, N, N-dimethylacrylamide, N, N-dibenzylacrylamide, methacrylformamide, N-methyl-N-vinylacetamide, N-vinylpyrrolidone, etc. Amide group-containing vinyl monomers such as

  Examples of the acid / alkyl ester group-containing monomer that is a constituent material of the resin containing at least the nitrogen-containing unit and the acid / alkyl ester group-containing unit include the following.

  Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate Acrylates such as n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate , Methacrylates such as n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate; vinyl sulfonic acid, allyl sulfonic acid, methyl vinyl sulfonic acid, styrene sulfonic acid, α- Styrene sulfonic acid, sulfopropyl acrylate, 2-hydroxy-3-acryloxypropyl sulfonic acid, 2-acryloyloxyethane sulfonic acid, 3-acryloyloxy-2-hydroxypropane sulfonic acid, propyl allyl sulfosuccinic acid, butyl allyl sulfosuccinic acid 2-ethylhexyl-allylsulfosuccinic acid.

  The method for producing the resin containing at least the nitrogen-containing unit and the acid / alkyl ester group-containing unit may be any method, and a known method such as a solution polymerization method or a suspension polymerization method can be used.

  At this time, in order to control physical properties such as the glass transition temperature of the obtained resin, other vinyl monomers can be used in addition to the above two types of vinyl monomers. Specifically, the same polymerizable monomer used as the main constituent material of the above-described core particle can be used.

  The polymerization initiator used in the production of the core particles is not particularly limited, and a known peroxide polymerization initiator or azo polymerization initiator can be used.

  Examples of peroxide polymerization initiators include the following. t-butyl peroxylaurate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, t- Butyl peroxyacetate, t-butyl peroxyisononanoate, t-butyl peroxybenzoate, t-amyl peroxyneodecanoate, t-amyl peroxypivalate, t-amyl peroxy-2-ethylhexano Ate, t-amyl peroxyacetate, t-amyl peroxyisononanoate, t-amyl peroxybenzoate, t-hexyl peroxyneodecanoate, t-hexyl peroxypivalate, t-hexyl peroxy-2 -Ethyl hexanoate, t-hexyl peroxybenzoe Α-cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate 1-cyclohexyl-1-methylethylperoxyneodecanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 2,5-dimethyl-2,5-bis ( Peroxyester polymerization such as benzoylperoxy) hexane, t-butylperoxy-3,5,5-trimethylhexanoate, 2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane Initiator: di-n-propyl peroxydicarbonate, di-n-butyl peroxydicarbonate, di-n-pentylperoxydicarbonate Diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, di (3-methoxybutyl) peroxydi Peroxydicarbonate-based polymerization initiators such as carbonate and di (4-t-butylcyclohexyl) peroxydicarbonate; diisobutyryl peroxide, diisononanoyl peroxide, di-n-octanoyl peroxide, dilauroylper Diacyl peroxide polymerization initiators such as oxide, distearoyl peroxide, dibenzoyl peroxide, di-m-toluoyl peroxide, benzoyl-m-toluoyl peroxide; t-hexyl peroxide Peroxymonocarbonate polymerization initiators such as pill monocarbonate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexyl monocarbonate, t-butylperoxyallyl monocarbonate; 1,1-di-t -Hexylperoxycyclohexane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, 2,2-di-t-butylper Peroxyketal polymerization initiators such as oxybutane; dialkyl peroxide polymerization initiators such as dicumyl peroxide, di-t-butyl peroxide, and t-butylcumyl peroxide.

  Examples of the azo polymerization initiator include the following. 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis -4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile.

  Among these polymerization initiators, peroxide-based polymerization initiators are preferable because there is little residue of decomposition products. In addition, two or more of these polymerization initiators can be used simultaneously as necessary. In this case, the preferred amount of the polymerization initiator used is 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  In the production of the core particles, a chain transfer agent can be used for the purpose of adjusting the molecular weight. Examples of the chain transfer agent include the following. n-pentyl mercaptan, isopentyl mercaptan, 2-methylbutyl mercaptan, n-hexyl mercaptan, n-heptyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, t-nonyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, alkyl mercaptans such as n-tetradecyl mercaptan, t-tetradecyl mercaptan, n-pentadecyl mercaptan, n-hexadecyl mercaptan, t-hexadecyl mercaptan, stearyl mercaptan; alkyl esters of thioglycolic acid; mercaptopropionic acid Alkyl esters; halogenated hydrocarbons such as chloroform, carbon tetrachloride, ethylene bromide, carbon tetrabromide; α-methylstyrene dimer.

  These chain transfer agents are not necessarily used, but a preferable addition amount when used is 0.05 to 3 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  In the production of the core particles, as the dispersion stabilizer added to the aqueous medium, known surfactants, organic dispersants, and inorganic dispersants can be used. Among these, inorganic dispersants can be suitably used because they are less likely to produce ultrafine powder during polymerization, are less likely to lose stability even when the polymerization temperature is changed, are easily washed with acid, and do not adversely affect the toner. . Examples of such inorganic dispersants include the following. Polyvalent metal phosphates such as tricalcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; inorganic salts such as calcium metasuccinate, calcium sulfate and barium sulfate; Inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite and alumina.

  When these inorganic dispersants are used, they may be used as they are in an aqueous medium, but in order to obtain finer particles, they are prepared and used in an aqueous medium using a compound capable of generating inorganic dispersant particles. You can also. For example, in the case of tricalcium phosphate, sodium phosphate aqueous solution and calcium chloride aqueous solution can be mixed under high-speed stirring to produce water-insoluble tricalcium phosphate, which enables more uniform and fine dispersion. Become. These inorganic dispersants can be almost completely removed by adding an acid or an alkali after the polymerization and dissolving.

  These inorganic dispersants are preferably used alone in an amount of 0.2 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer, but if necessary, 0.001 to 0.1 parts by mass. These surfactants may be used in combination. Examples of the surfactant include the following. Sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate.

  The resin fine particles used in the present invention may be produced by any method, and those produced by a known method such as an emulsion polymerization method, a soap-free emulsion polymerization method, or a phase inversion emulsification method may be used. it can. Among these production methods, the phase inversion emulsification method is particularly suitable because it does not require an emulsifier or a dispersion stabilizer and resin particles having a smaller particle diameter can be easily obtained.

  In the phase inversion emulsification method, a resin having self-water dispersibility or a resin capable of expressing self-water dispersibility by neutralization is used. Here, the resin having self-water dispersibility is a resin containing in the molecule a functional group capable of self-dispersion in an aqueous medium, and specifically includes a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group. Or it is resin containing these salts. Further, a resin that can exhibit self-water dispersibility by neutralization is a resin that contains functional groups in the molecule that can increase self-dispersibility in an aqueous medium by neutralization.

  When these self-water-dispersed resins are dissolved in an organic solvent, a neutralizing agent is added as necessary, and mixed with an aqueous medium while stirring, the resin solution causes phase inversion emulsification to form fine particles. Generate. The organic solvent is removed using a method such as heating and decompression after phase inversion emulsification.

  Thus, according to the phase inversion emulsification method, a stable aqueous dispersion of resin fine particles can be obtained without substantially using an emulsifier or a dispersion stabilizer due to the action of the functional group.

  The resin fine particles obtained in this manner can be directly used as an aqueous dispersion for the fixing step to the core particles. Further, an acid may be added to the aqueous dispersion to return the acidic group in the resin from the salt state to the acid state, and after filtration and washing, the acid group may be redispersed in water.

  The resin material may be any material that can be used as a binder resin for toner, and vinyl resin, polyester resin, epoxy resin, and urethane resin are used.

  The organic solvent is not particularly limited as long as it dissolves the resin, but it is more preferable to use a low boiling point solvent that can be easily removed.

  The acid value of the resin constituting the resin fine particles is preferably 5.0 to 30.0 mgKOH / g. If the acid value is within such a range, sufficient self-water dispersibility can be exhibited, and the hygroscopicity does not become too high when the toner is formed, so that stable tribocharging can be obtained. .

  The acid value referred to here represents the total amount of functional groups contained in the resin constituting the resin fine particles. In the present invention, when the functional group is in the salt state, the acid value is returned to the acid state. Shown as the value of.

  The acid value can be determined in the same manner as described above. In particular, when obtaining the acid value derived from the sulfonic acid group, for example, quantitative analysis of S element is performed using an X-ray fluorescence analyzer (XRF), and the functional group equivalent contained in 1 g of the resin is set to the amount of potassium hydroxide. It is preferable to obtain by conversion.

  A preferable average particle diameter of the resin fine particles is a median diameter value determined by particle size distribution measurement by a laser scattering method, and is in the range of 10 to 100 nm. If the median particle diameter of the resin fine particles is within such a range, a toner having a sufficient thickness and a uniform outer shell can be formed, so that a toner having sufficient heat-resistant storage stability can be obtained.

  The median diameter is a particle diameter defined as a 50% value (central cumulative value) of a cumulative curve of particle size distribution. For example, a laser diffraction / scattering particle size distribution measuring apparatus (LA-) manufactured by HORIBA, Ltd. 920).

  When the resin fine particles are attached to the surface of the core particle, it is usually performed in a state where they are dispersed in an aqueous medium. When the polarities of the core particles and the resin fine particles are greatly different, they can be attached by an electric suction force. Otherwise, it is necessary to control the dispersion state of the resin fine particles using an external means. . As a specific method, in addition to the method of adjusting the pH of the aqueous medium described above, a method of adding an inorganic salt to the aqueous medium can be mentioned. In either case, if the dispersion state of the resin fine particles is suddenly changed, the resin fine particles cause single aggregation and cannot be uniformly adhered, so that these operations are preferably performed gradually.

  In addition, after the resin fine particles are attached, they are fixed or fused so that they do not easily peel off or fall off. As a specific method, a method of heat-treating in a state dispersed in an aqueous medium, a method of adding a solvent that dissolves or swells resin fine particles to absorb and forming a film, removing the solvent, filtration and A method of stirring and mixing the powder taken out after drying is heated. Among these methods, the heat treatment method in an aqueous medium is preferable in that it can be fixed more uniformly and firmly and the operation is simple. However, when the amount of the resin fine particles to be attached is small, or when the resin fine particles do not have a sufficiently high glass transition temperature with respect to the core particles, even the core particles may be fused.

  A particularly preferred example will be described in detail as a method for attaching and fixing the resin fine particles to the core particles.

  First, core particles are produced according to the suspension polymerization method described above. At this time, as the dispersion stabilizer, for example, an inorganic dispersant having a significantly different polarity with respect to the core particles such as tricalcium phosphate is used, and the dispersion stabilizer attached to the surface is not removed even after the core particles are produced. Continue stirring.

  Next, an aqueous dispersion of resin fine particles composed of a resin containing a carboxylic acid group and / or a sulfonic acid group is added to the core particle dispersion with the dispersion stabilizer attached. At this time, since the resin fine particles have the same polarity with respect to the dispersion stabilizer as the core particles, they uniformly adhere to the surface of the core particles with the dispersion stabilizer interposed.

  Next, while stirring this dispersion, the dispersion is heated to a temperature range not lower than the glass transition temperature of the core particles and not higher than the glass transition temperature of the resin fine particles.

  Then, while maintaining the temperature of the dispersion within the above temperature range, acid is slowly added thereto to adjust the pH of the dispersion to be equal to or lower than the pH at which the dispersion stabilizer is dissolved, and stirring is continued.

  In this way, when the dispersion stabilizer is gradually dissolved and the dispersion stabilizer is removed, the resin fine particles are simultaneously brought into contact with the surface of the core particle and fixed while maintaining a uniform state.

  In this way, it is possible to obtain a toner having a capsule structure that is a thin layer but has a coating layer that is homogeneous and excellent in mechanical strength.

  In the present invention, the coating layer formed of resin fine particles preferably covers 90% or more of the surface of the core particles, and particularly preferably 100%. A suitable use amount of the resin fine particles for satisfying such a coverage is not uniquely determined, and may be appropriately adjusted according to the particle diameters of the core particles and the resin fine particles. Further, the resin fine particles to be fixed do not necessarily have to be a single layer, and may be a multilayer in order to cover 100%.

  The coverage can be directly determined from an observation image of each toner cross section by a transmission electron microscope (TEM). When an element unique to the resin constituting the resin fine particle (for example, S element derived from a sulfonic acid group) is contained, the element contained in the toner is quantified using, for example, an X-ray fluorescence analyzer (XRF). It can also be obtained by analysis and calculation.

  Known colorants can be used as the colorant used in the toner of the present invention. Examples of the black colorant include carbon black, magnetic powder, and the following yellow / magenta / cyan colorants.

  Examples of the yellow colorant include the following. Condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, 180 are preferably used.

  Examples of the magenta colorant include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254 are preferably used.

  Examples of the cyan colorant include the following. Copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 are preferably used.

  These colorants can be used alone or in combination, and further in the form of a solid solution. When magnetic powder is used as the black colorant, the amount added is preferably 40 to 150 parts by mass with respect to 100 parts by mass of the binder resin in the core particles. When carbon black is used as the black colorant, the amount added is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin in the core particles. Further, in the case of a color toner, it is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in the toner, and the preferred addition amount is 100 parts by mass of the binder resin in the core particles. 1 to 20 parts by mass with respect to.

  These colorants need to pay attention to polymerization inhibition and aqueous phase migration, and are preferably subjected to surface modification such as a hydrophobization treatment as necessary. For example, a preferable method for surface-treating a dye-based colorant includes a method in which a polymerizable monomer is polymerized in the presence of a dye in advance, and the obtained colored polymer is added to the monomer composition. . For carbon black, in addition to the same treatment as the above dye, a grafting treatment may be performed with a substance that reacts with the surface functional group of carbon black, for example, polyorganosiloxane.

  The magnetic powder is mainly composed of iron oxide such as triiron tetroxide and γ-iron oxide, and generally has hydrophilicity. Therefore, the magnetic powder is likely to be unevenly distributed on the particle surface due to the interaction with water as a dispersion medium, and the resulting toner particles are inferior in fluidity and frictional charging uniformity due to the magnetic powder exposed on the surface. Become. Therefore, the surface of the magnetic powder is preferably subjected to a hydrophobic treatment uniformly with a coupling agent. Examples of the coupling agent that can be used include a silane coupling agent and a titanium coupling agent, and a silane coupling agent is particularly preferably used.

  The toner of the present invention contains a wax for improving fixability. Usable waxes include the following. Petroleum wax such as paraffin wax, microcrystalline wax, petrolatum and derivatives thereof; montan wax and derivatives thereof; hydrocarbon wax and derivatives thereof according to Fischer-Tropsch method; polyolefin wax and derivatives thereof represented by polyethylene; carnauba wax and candelilla Natural waxes such as waxes and derivatives thereof. Derivatives include block copolymers with oxides and vinyl monomers, and graft modified products. Furthermore, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant-based waxes and animal waxes can also be used. These waxes may be used alone or in combination of two or more.

  Among these waxes, those having a peak temperature of the maximum endothermic peak in the region of 40 to 130 ° C. at the time of temperature rise in the DSC curve measured by a differential scanning calorimeter are preferable, and further in the region of 45 to 120 ° C. What has is more preferable. By using such a wax, the releasability can be effectively expressed while greatly contributing to the low-temperature fixability.

  When the peak temperature of the maximum endothermic peak is too low, the self-cohesive force of the wax component becomes weak and the high temperature offset resistance is lowered. Further, exudation of wax is likely to occur at times other than during fixing, and the triboelectric charge amount of the toner is reduced, and the durability under high temperature and high humidity is reduced. On the other hand, if the peak temperature of the maximum endothermic peak is too high, the fixing temperature becomes high and low temperature offset tends to occur. Furthermore, the problem that a wax component precipitates during granulation arises, and the dispersibility of wax falls.

  The content of the wax is preferably 1 to 30 parts by mass and more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the binder resin. If the content of the wax is within such a range, a sufficient offset suppressing effect can be obtained, and the dispersibility of the material such as the colorant, the fluidity of the toner, the image characteristics, the stain of the wax component can be reduced. It is possible to prevent a decrease in durability under high temperature and high humidity due to taking out.

  The toner of the present invention can contain a charge control agent as necessary for the purpose of stabilizing the charge characteristics. As a method of inclusion, there are a method of adding to the inside of toner particles and a method of adding externally. As the charge control agent, a known one can be used, but when added inside, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable. Specific examples of the negative charge control agent include the following compounds. Metallic compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid; metal salts or metal complexes of azo dyes or azo pigments; polymer type having sulfonic acid or carboxylic acid group in the side chain Compound: Boron compound, urea compound, silicon compound, calixarene. Examples of positive charge control agents include quaternary ammonium salts, polymer compounds having quaternary ammonium salts in the side chain, guanidine compounds, nigrosine compounds, and imidazole compounds.

  The amount of these charge control agents to be used is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and a dispersion method, and is not uniquely limited. When added internally, it is preferably used in the range of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the binder resin. In the case of external addition, the amount is preferably 0.005 to 1.0 part by mass, more preferably 0.01 to 0.3 part by mass with respect to 100 parts by mass of the toner particles.

  The toner obtained according to the present invention has a weight average particle diameter (D4) of 3.0 to 10.0 μm in order to faithfully develop finer electrostatic latent image dots and obtain a high-quality image. preferable.

  If the weight average particle size is too small, transfer residual toner on the photoconductor increases due to a decrease in transfer efficiency, and it becomes difficult to suppress the photoconductor scraping and toner fusion in the contact charging step. In addition to the increase in the surface area of the entire toner, the fluidity and agitation as a powder are reduced, making it difficult to uniformly frictionally charge individual toners. It tends to decrease. On the other hand, if the weight average particle size is too large, characters and line images are likely to be scattered, and it becomes difficult to obtain high resolution. Also, the higher the resolution of the apparatus, the worse the reproducibility of 1 dot.

  Here, the average particle size and particle size distribution of the toner can be measured using a Coulter Counter TA-II type or Coulter Multisizer (both manufactured by Coulter). In the present invention, a Coulter multisizer was used, and an interface (manufactured by Nikka Machine Co., Ltd.) for outputting the number distribution and the volume distribution and a PC9801 personal computer (manufactured by NEC Corporation) were connected thereto. As the electrolytic solution, a 1% NaCl aqueous solution prepared using primary sodium chloride was 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 solution, and 2 to 20 mg of a measurement sample is further added. Next, the electrolytic solution is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the volume and number of particles having a size of 2 μm or more are measured by the Coulter Multisizer using a 100 μm aperture as an aperture. Calculate the distribution. Then, a weight average particle diameter (D4) and a number average particle diameter (D1) are obtained.

  The average circularity of the toner obtained by the present invention is preferably 0.970 or more. The average circularity is an index representing the degree of unevenness of toner particles, and is 1.000 when the toner is a perfect sphere, and the value becomes smaller as the shape becomes more complicated. That is, that the average circularity is 0.970 or more means that the toner shape is substantially spherical. The toner having such a shape is likely to have uniform frictional charging and is effective in suppressing fogging and sleeve ghosting. Further, since the toner ears formed on the toner carrier are uniform, control in the developing unit is facilitated. Furthermore, since it has a spherical shape, it has good fluidity and is not easily stressed in the developing device, so that the chargeability is not easily lowered even when used for a long time under high humidity. Further, since heat and pressure are easily applied to the entire toner even at the time of fixing, it contributes to improvement of fixing properties.

  The average circularity in the present invention was measured using a flow type particle image analyzer (FPIA-3000 type) manufactured by Sysmex Corporation.

  As a specific measurement method, an appropriate amount of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 20 ml of ion-exchanged water, and then 0.02 g of a measurement sample is added. Then, a dispersion process for 2 minutes is performed using a tabletop ultrasonic cleaner / disperser (eg, VS-150 manufactured by Vervo Creer) having an oscillation frequency of 50 kHz and an electric output of 150 W, To do. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC.

  For the measurement, the flow type particle image measuring apparatus equipped with a standard objective lens (10 times) is used, and a particle sheath (PSE-900A) manufactured by Sysmex Corporation is used as the sheath liquid. The dispersion liquid prepared according to the above procedure is introduced into the flow type particle image measuring apparatus, 3000 toner particles are measured in the total count mode, and the analysis particle diameter is limited to a circle equivalent diameter of 3.00 μm to 200.00 μm. The average circularity of the toner particles is obtained.

  In measurement, automatic focus adjustment is performed using standard latex particles (for example, a product obtained by diluting 5200A manufactured by Duke Scientific with ion-exchanged water) before the measurement is started. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In the examples, a flow-type particle image measuring apparatus that has been calibrated by Sysmex Corporation and that has been issued a calibration certificate issued by Sysmex Corporation was used. Measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that the analysis particle diameter was limited to a circle equivalent diameter of 3.00 μm or more and 200.00 μm or less.

  The toner of the present invention is preferably externally added with a fluidity improver to improve image quality. As the fluidity improver, inorganic fine powders such as silica, titanium oxide, and aluminum oxide are preferably used. These inorganic fine powders are preferably hydrophobized with a silane coupling agent, silicone oil, or both.

  The toner of the present invention can be used as it is as a one-component developer or as a two-component developer by mixing with a magnetic carrier. When used as a two-component developer, the average particle size of the carrier to be mixed is preferably 10 to 100 μm, and the toner concentration in the developer is preferably 2 to 15% by mass.

  Hereinafter, the production method of the present invention will be specifically described with reference to examples.

<Synthesis Example 1: Resin fine particle dispersion (a)>
(Production of polyester resin)
The following monomers were charged into a reaction vessel equipped with a stirrer, condenser, thermometer and nitrogen introduction tube, 0.03 parts by mass of tetrabutoxy titanate was added as an esterification catalyst, and the temperature was raised to 220 ° C. in a nitrogen atmosphere. Warmed and reacted for 5 hours with stirring.
Bisphenol A-propylene oxide 2 mol adduct: 49.0 parts by mass Ethylene glycol: 8.6 parts by mass Terephthalic acid: 21.8 parts by mass Isophthalic acid: 12.0 parts by mass 5-sodium sulfoisophthalic acid: 8.6 parts by mass Part Next, the reaction vessel was further reacted for 5 hours while reducing the pressure in the reaction vessel to 5 to 20 mmHg to obtain a polyester resin.

(Preparation of resin fine particle dispersion)
A reaction vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube was charged with 100.0 parts by mass of the obtained polyester resin, 45.0 parts by mass of methyl ethyl ketone, and 45.0 parts by mass of tetrahydrofuran, and heated to a temperature of 80 ° C. And dissolved.

  Next, after stirring, 300.0 parts by mass of ion-exchanged water having a temperature of 80 ° C. is added and dispersed in water, and the resulting aqueous dispersion is transferred to a distillation apparatus and distilled until the fraction temperature reaches 100 ° C. went.

  After cooling, ion-exchanged water was added to the obtained aqueous dispersion to adjust the resin concentration in the dispersion to 20%. This was designated as resin fine particle dispersion (a).

<Synthesis Example 2: Resin fine particle dispersion (b)>
(Production of polyester resin)
The following monomers were charged into a reaction vessel equipped with a stirrer, condenser, thermometer and nitrogen introduction tube, 0.03 parts by mass of tetrabutoxy titanate was added as an esterification catalyst, and the temperature was raised to 220 ° C. in a nitrogen atmosphere. Warmed and reacted for 5 hours with stirring.
Bisphenol A-propylene oxide 2 mol adduct: 49.5 parts by mass Ethylene glycol: 9.2 parts by mass Terephthalic acid: 23.0 parts by mass Isophthalic acid: 12.1 parts by mass Next, trimellitic anhydride 6.2 parts by mass Was added, and the reaction was further carried out for 5 hours while reducing the pressure in the reaction vessel to 5 to 20 mmHg to obtain a polyester resin.

(Preparation of resin fine particle dispersion)
A reaction vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube was charged with 100.0 parts by mass of the obtained polyester resin and 75.0 parts by mass of butyl cellosolve, heated to 90 ° C. and dissolved, then 70 Cooled to ° C.

  Next, 18.0 parts by mass of a 1 mol / liter aqueous ammonia solution was added, and the mixture was stirred for 30 minutes while maintaining the above temperature. Then, 300.0 parts by mass of ion-exchanged water having a temperature of 70 ° C. was added and dispersed in water. It was. The obtained aqueous dispersion was transferred to a distillation apparatus and distilled until the fraction temperature reached 100 ° C.

  After cooling, ion-exchanged water was added to the obtained aqueous dispersion to adjust the resin concentration in the dispersion to 20%. This was designated as resin fine particle dispersion (b).

  With respect to the resin fine particle dispersions (a) and (b) thus obtained, the average particle diameter (median diameter) of the resin fine particles in each of the dispersion liquids is determined by a laser diffraction / scattering particle size distribution measuring apparatus LA-920 (Horiba, Ltd.). The measurement was performed using

  Further, the zeta potential of each resin fine particle was measured using an ultrasonic zeta potential measuring device DT-1200 (manufactured by Dispersion Technology), and the pH value indicating the isoelectric point was determined according to the above-described method.

  Moreover, after extracting a part of each dispersion liquid, filtering and washing | cleaning, drying and taking out as solid content, the acid value and glass transition temperature of the resin which were obtained were measured, respectively. The carboxylic acid value was determined by the above-described titration method, and the sulfonic acid value was determined by calculation from the quantitative result of S element by a fluorescent X-ray analyzer (XRF).

  The results are shown in Table 1.

<Synthesis Example 3: Intermediate Layer Forming Resin (a)>
Into a reaction vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube, 200 parts by mass of xylene was charged, and the inside of the reaction vessel was sufficiently replaced with nitrogen gas, and then heated until xylene refluxed.

Next, the following vinyl monomer is mixed, and 5.0 parts by mass of di-t-butyl peroxide is added thereto as a polymerization initiator and added dropwise to the reaction vessel, which is then maintained for 10 hours in a nitrogen atmosphere. Then, a polymerization reaction was performed.
Dimethylaminoethyl methacrylate: 6.0 parts by weight Methyl methacrylate: 93.7 parts by weight Acrylic acid: 0.3 parts by weight Thereafter, the solvent component is distilled off by distillation and dried at 50 ° C. under reduced pressure. Thus, a vinyl polymer was obtained. This was designated as intermediate layer forming resin (a).

<Synthesis Examples 4 to 9: Intermediate layer forming resins (b) to (g)>
In Synthesis Example 3, the polymerization reaction was performed in the same manner as in Synthesis Example 3 except that the type and amount (parts by mass) of the vinyl-based monomer were changed as shown in Table 2 below. (B) to (g) were obtained.

  About the obtained resin (a) thru | or (g) for intermediate | middle layer formation, the value of the acid value was calculated | required by the titration method. The results are shown in Table 2.

DM: dimethylaminoethyl methacrylate, VPri: 4-vinylpyridine,
VPro: N-vinylpyrrolidone, MMA: methyl methacrylate, BA: n-butyl acrylate,
AA: Acrylic acid, St: Styrene, HEMA: Methacrylic acid-2-hydroxyethyl

<Synthesis Example 10: Core particle dispersion (A1)>
(Preparation of pigment dispersion paste)
Styrene: 213.2 parts by mass Cu phthalocyanine (CI Pigment Blue 15: 3): 20.0 parts by mass After sufficiently premixing the above materials in a container, the attritor ( A pigment dispersion paste was prepared by dispersing and mixing for about 4 hours using Mitsui Miike Kako Co., Ltd.

(Preparation of core particle dispersion)
Into 1152.0 parts by mass of ion-exchanged water, 390.0 parts by mass of a 0.1 mol / liter-sodium phosphate (Na ₃ PO ₄ ) aqueous solution was added and stirred using CLEARMIX (M Technique Co., Ltd.). , Heated to 60 ° C. To this, 58.0 parts by mass of 1.0 mol / liter-calcium chloride (CaCl ₂ ) aqueous solution was added and stirring was continued, and a dispersion stabilizer composed of tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ ) was added. An aqueous medium containing was prepared.

On the other hand, the following materials were added to the pigment dispersion paste and dispersed and mixed using an attritor (manufactured by Mitsui Miike Chemical Industries) to prepare a polymerizable monomer composition.
N-Butyl acrylate: 114.8 parts by mass Resin for forming an intermediate layer (a): 20.0 parts by mass The monomer composition was heated to 60 ° C., and this was added to an ester wax (main component C ₁₉ H ₂₉ COOC ₂₀ H ₄₁ , DSC maximum endothermic peak temperature 68.6 ° C.) 32.0 parts by mass was added and mixed and dissolved.

  Next, 9.8 parts by mass of 2,2'-azobis (2,4-dimethylvaleronitrile) was further added and dissolved as a polymerization initiator.

  This was put into the aqueous medium, and granulated by stirring for 15 minutes at a rotation speed of 12,000 rpm under a nitrogen atmosphere at a temperature of 60 ° C. using CLEARMIX (M Technique Co., Ltd.).

  Furthermore, polymerization was performed at a temperature of 60 ° C. for 10 hours while stirring the obtained suspension with a paddle stirring blade.

  After completion of the polymerization, the obtained dispersion of polymer particles was cooled, and ion exchange water was added to adjust the concentration of the polymer particles in the dispersion to 20% by mass. This was designated as core particle dispersion (A1).

<Synthesis Example 11: Core particle dispersion (A2)>
In Synthesis Example 10, 213.2 parts by mass of styrene used in the process of preparing the pigment dispersion paste is 223.6 parts by mass, and n-butyl acrylate used in the process of preparing the core particle dispersion is 120. A core particle dispersion (A2) was prepared in the same manner as in Synthesis Example 10 except that 20.0 parts by mass of the intermediate layer forming resin (a) was changed to 4.0 parts by mass in 4 parts by mass.

<Synthesis Example 12: Core particle dispersion (A3)>
In Synthesis Example 10, 213.2 parts by mass of styrene used in the process of preparing the pigment dispersion paste is 200.2 parts by mass, and n-butyl acrylate used in the process of preparing the core particle dispersion: 107. 8 parts by mass. A core particle dispersion (A3) was produced in the same manner as in Synthesis Example 10 except that 80.0 parts by mass of the intermediate layer forming resin (a) 20.0 parts by mass was changed to 40.0 parts by mass.

<Synthesis Examples 13 to 16: Core particle dispersions (B) to (E)>
In Synthesis Example 10, the core particle dispersion (B) was prepared in the same manner as in Synthesis Example 10 except that the intermediate layer forming resins (b) to (e) were used instead of the intermediate layer forming resin (a). Thru (E) were produced.

<Synthesis Examples 17 and 18>
In Synthesis Example 10, instead of the intermediate layer forming resin (a), the intermediate layer forming resins (f) and (g) were used, respectively. In either case, the droplets aggregated during the polymerization reaction, and polymer particles could not be obtained.

  For the prepared core particle dispersions (A1) to (A3) and core particle dispersions (B) to (E), the zeta potential of each core particle in the dispersion is measured, and the isoelectric point is determined according to the method described above. The pH value indicating was determined.

  Further, a part of each dispersion was taken out and hydrochloric acid was added to remove the dispersion stabilizer, followed by filtration, washing with water and drying.

  The core particles (A1) to (A3) and the core particles (B) to (E) thus obtained were measured for average particle diameter, average circularity, and glass transition temperature. The results are shown in Table 3.

  * The content of the intermediate layer forming resin was determined by calculation from the blending ratio at the time of core particle preparation.

  From Table 3, the isoelectric points of the core particles (A1) to (A3) and (B) to (D) using the resin containing both the nitrogen-containing unit and the acid / alkyl ester group-containing unit are the acid / It can be seen that all of them are greatly shifted to the high pH side as compared with the core particles (E) using the resin containing only the alkyl ester group-containing unit.

<Example 1>
(Production of toner particles)
Under stirring, 25.0 parts by mass of the resin fine particle dispersion (a) (5.0 parts by mass of solids) is added to 500.0 parts by mass (A1) of the core particle dispersion (A1). After stirring for 30 minutes, the temperature was raised to 60 ° C.

  Next, a 0.2 mol / liter hydrochloric acid aqueous solution was added dropwise at a dropping rate of 0.005 liter / min until the pH of the dispersion reached 1.50.

  Stirring was continued for 3 hours while maintaining the above temperature, followed by cooling, filtering, washing with water and drying to obtain toner particles.

(Production of toner)
100 parts by mass of untreated silica fine powder is treated with 10 parts by mass of hexamethyldisilazane and further with 10 parts by mass of silicone oil to give a number average primary particle size of 12 nm and a BET specific surface area of 120 m ² / g. A hydrophobic silica fine powder was prepared. Next, 1.0 part by mass of the hydrophobic silica fine powder was added to 100.0 parts by mass of the toner particles, and mixed using a Henschel mixer (manufactured by Mitsui Miike Chemical Industries). Thus, the toner of the present invention was produced.

<Example 2>
A toner of the present invention was produced in the same manner as in Example 1 except that instead of the resin fine particle dispersion (a), the resin fine particle dispersion (b) was used.

<Examples 3 to 7>
In Example 1, instead of the core particle dispersion (A1), the core particle dispersions (A2) to (A3) and the core particle dispersions (B) to (D) were used, respectively. In the same manner as in Example 1, a toner of the present invention was produced.

<Comparative Example 1>
In Example 1, the resin fine particle dispersion (b) was used instead of the resin fine particle dispersion (a), and the core particle dispersion (E) was used instead of the core particle dispersion (A1). A comparative toner was prepared in the same manner as in Example 1 except for the above.

<Comparative example 2>
(Preparation of core particles)
Hydrochloric acid was added to the core particle dispersion (E) to remove the dispersion stabilizer, followed by filtration, washing with water and drying to obtain core particles (E).

(Production of toner particles)
The fine particle dispersion (b) 50.0 parts by mass (solid content 10.0 parts by mass) is added to 380.0 parts by mass of ion-exchanged water, and 100.0 parts by mass of the core particles (E) are gradually added while stirring. And uniformly dispersed.

  A 1 mol / liter hydrochloric acid aqueous solution was added thereto to adjust the pH of the dispersion to 2.0, and the mixture was stirred for 1 hour. Then, the temperature of the dispersion was raised to 60 ° C., and further stirred for 5 hours. It was.

  Next, the obtained dispersion was cooled, filtered, washed with water and dried to obtain toner particles.

(Production of toner)
A hydrophobic silica fine powder was externally added to the obtained toner particles in the same manner as in Example 1 to prepare a comparative toner.

<Comparative Example 3>
Without adding the resin fine particle dispersion to the core particle dispersion (A), a 1 mol / liter aqueous hydrochloric acid solution was added to dissolve the dispersion stabilizer, followed by filtration, washing with water and drying to obtain toner particles.

  A hydrophobic silica fine powder was externally added to the obtained toner particles in the same manner as in Example 1 to prepare a comparative toner.

<Comparative example 4>
Without adding the resin fine particle dispersion to the core particle dispersion (E), a 1 mol / liter aqueous hydrochloric acid solution was added to dissolve the dispersion stabilizer, followed by filtration, washing with water and drying to obtain toner particles.

  A hydrophobic silica fine powder was externally added to the obtained toner particles in the same manner as in Example 1 to prepare a comparative toner.

  For the toners obtained in Examples 1 to 7 and Comparative Examples 1 to 4, the average particle diameter and average circularity were measured. Moreover, evaluation of blocking resistance and low-temperature fixability was performed according to the procedure described below.

<Blocking resistance>
10 g of toner is weighed into a 100 ml capacity polycup and placed in a thermostat with an internal temperature of 50 ° C. and left for 7 days. Thereafter, the polycup is taken out, and the state change of the toner inside is visually evaluated. Judgment criteria are as follows.
A: No change B: There is an aggregate, but loosens immediately C: A little aggregate, difficult to loosen D: Many aggregates, not easily loosened E: Not loosened at all

<Low-temperature fixability>
A two-component developer is prepared by mixing toner and a magnetic fine particle-dispersed resin carrier (average particle size 35 μm) surface-coated with a silicone resin so that the toner concentration becomes 7.0% by mass.

  Next, the two-component developer is allowed to stand for 7 days at high temperature and high humidity (30 ° C./80%), and then left for another 3 days at room temperature and normal humidity (23 ° C./60%). Reset.

As a test machine, a commercially available full-color copying machine (CLC-700, manufactured by Canon Inc.) was used, and an unfixed toner image (toner applied amount per unit area of 0. 0 g / m ² ) on an image receiving paper (80 g / m ² ). 6 mg / cm ² ).

  The fixing test is performed using a fixing unit which is removed from the copying machine and modified so that the fixing temperature can be adjusted. The specific evaluation method is as follows.

  In a normal temperature and humidity environment (23 ° C, 60% RH), the process speed is set to 180 mm / s, the initial temperature is set to 120 ° C, and the set temperature is sequentially raised by 5 ° C, and the unfixed state at each temperature. Fix the image.

In the present invention, the low temperature fixability is the density reduction rate before and after rubbing when the low temperature offset is not observed and the obtained fixed image is rubbed 5 times with sylbon paper applied with a load of 4.9 kPa. Was the fixing start temperature, and the evaluation was made according to the following criteria.
A: Fixing start temperature is less than 120 ° C. (low temperature fixing performance is particularly excellent)
B: Fixing start temperature is 120 ° C. or higher and lower than 125 ° C. (low temperature fixing performance is good)
C: Fixing start temperature is 125 ° C. or higher and lower than 130 ° C. (low temperature fixing performance is at a level where there is no problem)
D: Fixing start temperature is 130 ° C. or higher and lower than 135 ° C. (low temperature fixing performance is slightly inferior)
E: Fixing start temperature is 140 ° C. or higher (low temperature fixing performance is inferior)

  The results are shown in Table 4.

Claims (5)

Binder resin, a core particle containing a colorant and a wax scan, a toner having toner particles composed of a coating layer formed by fixing the fine resin particles on the surface of the core particles,
A vinyl monomer containing (i) a nitrogen-containing vinyl monomer and (ii) a carboxylic acid group and / or a sulfonic acid group or an alkyl ester group thereof at the interface between the core particle and the coating layer. A toner comprising a copolymer resin obtained by copolymerization using at least a toner. 2. The toner according to claim 1, wherein the content of the copolymer resin contained in the core particle is 0.5 to 20.0 mass%. After the core particles were at least the copolymer resin in the polymerizable monomer, the colorant and the polymerizable monomer composition made adjustment by dissolving or dispersing the wax is suspended in an aqueous medium, The toner according to claim 1, wherein the toner is obtained by polymerizing the polymerizable monomer. After the core layer is produced in the aqueous medium in which the dispersion stabilizer is dispersed, the resin fine particles are added to the aqueous medium to adhere to the surface of the core particle, and the pH is adjusted to adjust the dispersion. the toner according to any one of claims 1 to 3, characterized in that fixed to dissolve the stabilizer, is obtained by forming. The toner according to any one of claims 1 to 4, wherein the resin fine particles are composed of a resin having a carboxylic acid group and / or a sulfonic acid group.