JP7394600B2 - Toner for electrophotography - Google Patents

Description

The present invention relates to an electrophotographic toner used for developing latent images formed in, for example, electrophotography, electrostatic recording, electrostatic printing, and the like.

With the demand for higher image quality, toners that aim to improve fine line reproducibility are being considered.

Patent Document 1 describes a negatively chargeable toner containing colored resin particles containing at least a binder resin, a colorant, a charge control agent, and a softening agent, in which the charge control agent comprises a vinyl aromatic hydrocarbon and a (meth)acrylate. and sulfonic acid group-containing (meth)acrylamide, and the copolymerization ratio of the sulfonic acid group-containing (meth)acrylamide is 0.8 to 4.0% by mass, A negatively chargeable toner is disclosed in which the softening agent is at least one of a monoester compound and a polyglycerol ester compound.

Patent Document 2 discloses an electrophotographic toner containing a binder resin, a colorant, and a charge control agent, wherein the binder resin contains an alcohol component and an aliphatic dicarboxylic acid compound in an amount of 60 mol% or more. contains 50% by mass or more of polyester resin A, which is a polycondensate with a carboxylic acid component, and the colorant contains 5 parts by mass or more of C.I.Pigment Red 188 based on 100 parts by mass of the binder resin, An electrophotographic toner is disclosed in which the charge control agent contains a metal compound of benzylic acid compound.

JP2019-70835A JP2019-95575A

In order to improve fine line reproducibility in a non-magnetic one-component development system, it is important that toner particles flow smoothly and be uniformly charged by stirring in a developing machine. Due to their physical and electrical properties, inorganic fine particles are often added externally to toner particles. However, when externally added to toner particles, they are not effective as they become loose or embedded during agitation in the developing machine, and the toner becomes Aggregation may occur between particles, which may deteriorate fine line reproducibility.

The present invention relates to an electrophotographic toner with excellent fine line reproducibility of images.

The present invention relates to an electrophotographic toner containing a binder resin and magnesium aluminometasilicate.

The electrophotographic toner of the present invention exhibits excellent effects in terms of fine line reproducibility of images.

The electrophotographic toner of the present invention contains a binder resin and magnesium aluminate metasilicate, and exhibits an excellent effect in fine line reproducibility of images (hereinafter also simply referred to as "thin line reproducibility").
Normally, when inorganic particles are internally added to toner particles, the inorganic particles are difficult to disperse into the toner, and as a result, differences in charging performance depending on the amount of inorganic particles occur between toner particles, which deteriorates fine line reproducibility. I'll let you.
In contrast, in the present invention, since magnesium metasilicate aluminate is electrically neutral, even if particles containing a large amount of magnesium metasilicate aluminate are present, the charging characteristics are not adversely affected; By acting like giant spacer particles between toner particles and preventing aggregation between toner particles, fine line reproducibility can be improved.

Magnesium metasilicate aluminate has antacid and antiulcer effects and is used as a raw material for gastrointestinal drug preparations and the like.

The number average particle diameter of magnesium aluminometasilicate is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 0.2 μm or less, more preferably 0.15 μm or less, from the viewpoint of introduction into the toner. More preferably, it is 0.1 μm or less.

The content of magnesium metasilicate aluminate is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 20 parts by mass or less, more preferably 13 parts by mass, based on 100 parts by mass of the binder resin. It is not more than 3 parts by mass, more preferably not more than 3 parts by mass.

The binder resin is not particularly limited, and examples thereof include polyester resin, vinyl resin such as styrene-acrylic resin, epoxy resin, polycarbonate, polyurethane, and composite resin containing two or more of these resins. , preferably contains polyester resin.

The polyester resin in the present invention may be amorphous or crystalline, and the binder resin may contain the polyester resin as a part of the composite resin.
Therefore, suitable binder resins containing polyester resins in the present invention include amorphous polyester resins, amorphous polyester resins and crystalline polyester resins, amorphous polyester resins and crystalline composite resins, and amorphous composite resins. Examples include resin and crystalline polyester resin, amorphous composite resin and crystalline composite resin, etc. Among these, amorphous polyester resin, a combination of amorphous polyester resin and crystalline polyester resin, and amorphous A combination of an amorphous composite resin and a crystalline polyester is preferred, and a combination of an amorphous polyester resin and a crystalline polyester resin and a combination of an amorphous composite resin and a crystalline polyester resin are more preferred.

The crystallinity of the resin is expressed by a crystallinity index defined by the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the value of [softening point/maximum endothermic peak temperature]. The crystalline resin has a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less, while amorphous resin is a resin with a crystallinity index of more than 1.4, preferably more than 1.5, more preferably 1.6 or more, or less than 0.6, preferably 0.5 or less. The crystallinity of the resin can be adjusted by the types and ratios of raw material monomers, manufacturing conditions (for example, reaction temperature, reaction time, cooling rate), and the like. Note that the maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. For crystalline resins, the maximum peak temperature of endotherm is defined as the melting point.

The amorphous polyester resin is preferably a polycondensate of an alcohol component and a carboxylic acid component.

Examples of the alcohol component include aliphatic diols, preferably carbon atoms of 2 to 20, more preferably carbon atoms of 2 to 15, and formula (I):

(In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and/or a propylene group, x and y indicate the average number of added moles of alkylene oxide, and each is a positive number, x and y The sum value is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less)
Examples include alkylene oxide adducts of bisphenol A represented by the following, bisphenol A, hydrogenated bisphenol A, and glycerin. Specific examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol.

As the alcohol component, from the viewpoint of fine line reproducibility, an alkylene oxide adduct of bisphenol A represented by formula (I) is preferable. The content of the alkylene oxide adduct of bisphenol A represented by formula (I) is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, even more preferably It is 95 mol% or more, more preferably 100 mol%.

In the carboxylic acid component, divalent carboxylic acid compounds include, for example, dicarboxylic acids having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, and their anhydrides. , or derivatives such as alkyl esters in which the alkyl group has 1 to 3 carbon atoms. Specific examples of dicarboxylic acids include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; fumaric acid, maleic acid, succinic acid, glutaric acid, adipic acid, and sebacic acid; Examples include aliphatic dicarboxylic acids such as succinic acid substituted with an aliphatic hydrocarbon group.

The carboxylic acid component preferably contains an aromatic dicarboxylic acid compound from the viewpoint of fine line reproducibility. The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 10 mol% or more, more preferably 25 mol% or more, even more preferably 40 mol% or more, and 100 mol% or less, preferably It is 90 mol% or less, more preferably 80 mol% or less.

Examples of trivalent or higher carboxylic acid compounds include carbon atoms of 4 to 20, preferably 6 to 20 carbon atoms, more preferably 7 to 15 carbon atoms, even more preferably 8 to 12 carbon atoms, and Preferred examples include trivalent or higher carboxylic acids having 9 to 10 carbon atoms, their anhydrides, and derivatives such as alkyl esters in which the alkyl group has 1 to 3 carbon atoms. Specific examples include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid), and acid anhydrides thereof.

From the viewpoint of adjusting the molecular weight of the polyester resin, the content of the trivalent or higher carboxylic acid compound is preferably 3 mol% or more, more preferably 5 mol% or more, and even more preferably 8 mol% or more in the carboxylic acid component. The content is preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 20 mol% or less.

Note that the alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate from the viewpoint of adjusting the molecular weight and softening point of the polyester resin.

From the viewpoint of adjusting the softening point of the polyester resin, the equivalent ratio of the carboxylic acid component to the alcohol component (COOH group/OH group) in the polyester resin is preferably 0.6 or more, more preferably 0.7 or more, and even more preferably 0.75 or more. Yes, and preferably 1.1 or less, more preferably 1.05 or less.

The amorphous polyester resin is produced by, for example, combining an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and if necessary, in the presence of an esterification co-catalyst, a polymerization inhibitor, etc. It can be produced by polycondensation at a temperature of preferably 130°C or higher, more preferably 170°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

In the present invention, the polyester resin may be a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include grafting or blocking with phenol, urethane, epoxy, etc. by methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Among the modified polyester resins, urethane-modified polyester resins obtained by urethane stretching a polyester resin with a polyisocyanate compound are preferred.

As the amorphous composite resin, a composite resin containing the amorphous polyester resin and a styrene resin is preferable.

The styrenic resin is an addition polymer of a raw material monomer containing at least styrene or a styrene derivative such as α-methylstyrene or vinyltoluene (hereinafter, styrene and styrene derivatives are collectively referred to as "styrene compound").

The content of the styrene compound, preferably styrene, is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, from the viewpoint of improving storage stability in the raw material monomer of the styrenic resin. and is preferably 95% by mass or less, more preferably 93% by mass or less, even more preferably 90% by mass or less.

Further, the styrene resin may contain a (meth)acrylic acid alkyl ester in which the alkyl group has 7 or more carbon atoms as a raw material monomer. Examples of (meth)acrylic acid alkyl esters include 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, and (iso)stearyl (meth)acrylate. Can be mentioned. It is preferable to use one or more of these. In addition, in this specification, "(iso)" means both the case where this group is present and the case where it is not, and when these groups are not present, it is normal. Show that. Furthermore, "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, or both.

The content of the (meth)acrylic acid alkyl ester having 7 or more carbon atoms is preferably 5% by mass or more, more preferably 7% by mass from the viewpoint of improving the low-temperature fixing properties of the toner in the raw material monomer of the styrene resin. The content is more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 30% by mass or less, and still more preferably 20% by mass or less.

The number of carbon atoms in the alkyl group in the (meth)acrylic acid alkyl ester as a raw material monomer for the styrene resin is preferably 7 or more, more preferably 8 or more, from the viewpoint of improving the low-temperature fixing properties of the toner. From the viewpoint of stability, it is preferably 12 or less, more preferably 10 or less. Note that the number of carbon atoms in the alkyl ester refers to the number of carbon atoms derived from the alcohol component constituting the ester.

Raw material monomers for styrenic resins include raw material monomers other than styrene compounds and (meth)acrylic acid alkyl esters, such as ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; and vinyl chloride. Halobinyls; vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic acid esters such as dimethylaminoethyl (meth)acrylate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; N-vinyl N-vinyl compounds such as pyrrolidone may also be included.

The addition polymerization reaction of raw material monomers for styrenic resin can be carried out, for example, in the presence of a polymerization initiator such as dicumyl peroxide, a polymerization inhibitor, a crosslinking agent, etc., in the presence of an organic solvent, or in the absence of a solvent. The temperature conditions are preferably 110°C or higher, more preferably 140°C or higher, and preferably 200°C or lower, more preferably 170°C or lower.

When using an organic solvent during the addition polymerization reaction, xylene, toluene, methyl ethyl ketone, acetone, etc. can be used. The amount of the organic solvent used is preferably 10 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the raw material monomer of the styrene resin.

In the present invention, from the viewpoint of crushability, the composite resin is capable of reacting with the amorphous polyester resin and styrene via a bireactive monomer that can react with either the raw material monomer of the amorphous polyester resin or the raw material monomer of the styrene resin. A resin in which the system resin is chemically bonded is preferable.

The bireactive monomer has at least one functional group selected from the group consisting of a hydroxyl group, a carboxy group, an epoxy group, a primary amino group, and a secondary amino group, preferably a hydroxyl group and/or a carboxy group, in the molecule. A compound having a group, more preferably a carboxyl group, and an ethylenically unsaturated bond is preferable, and at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid and maleic anhydride is more preferable. From the viewpoint of reactivity in polycondensation reactions and addition polymerization reactions, at least one selected from the group consisting of acrylic acid, methacrylic acid, and fumaric acid is more preferable. However, when used together with a polymerization inhibitor, a polyhydric carboxylic acid compound having an ethylenically unsaturated bond, such as fumaric acid, functions as a raw material monomer for an amorphous polyester resin. In this case, fumaric acid and the like are not bireactive monomers but are raw material monomers for the amorphous polyester resin.

Further, the bireactive monomer may be one or more (meth)acrylic esters selected from acrylic esters and methacrylic esters whose alkyl group has 6 or less carbon atoms.

The (meth)acrylic ester is preferably an alkyl (meth)acrylic ester from the viewpoint of reactivity to transesterification, and the number of carbon atoms in the alkyl group is preferably 2 or more, more preferably 3 or more, and preferably is 6 or less, more preferably 4 or less. The alkyl group may have a substituent such as a hydroxyl group.

Specifically, (meth)acrylic acid alkyl esters include ethyl (meth)acrylate, (iso)propyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid (iso or (tertiary) butyl, hexyl (meth)acrylate, and the like. In addition, "(iso or tertiary)" means both cases where these groups are present and cases where they are not, and when these groups are not present, it is normal. shows.

In the present invention, the acrylic ester is preferably an acrylic alkyl ester in which the number of carbon atoms in the alkyl group is 2 or more and 6 or less, more preferably butyl acrylate, and the methacrylic ester is preferably an acrylic ester in which the number of carbon atoms in the alkyl group is 2 or more and 6 or less. A methacrylic acid alkyl ester having a number of 2 or more and 6 or less, more preferably butyl methacrylate.

The amount of bireactive monomer used is determined from the viewpoint of increasing the dispersibility of the styrene resin and the amorphous polyester resin and improving the durability of the toner, based on the total 100 moles of the alcohol component of the amorphous polyester resin. , preferably 1 mol or more, more preferably 2 mol or more, and from the viewpoint of low-temperature fixability, preferably 30 mol or less, more preferably 20 mol or less, still more preferably 10 mol or less.
In addition, the amount of the bireactive monomer used is determined from the viewpoint of increasing the dispersibility of the styrene resin and the amorphous polyester resin and improving the durability of the toner, based on the total of 100 parts by mass of the raw material monomer of the styrene resin. from the viewpoint of low-temperature fixability, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less. It is. Here, the total amount of raw material monomers for the styrene resin includes the polymerization initiator.

Specifically, the composite resin obtained using the bireactive monomer is preferably manufactured by the following method. The bireactive monomer is preferably used in the addition polymerization reaction together with the raw material monomer of the styrene resin from the viewpoint of improving the durability of the toner, the low-temperature fixing property, and the heat-resistant storage stability of the toner.

(i) A method in which step (A) of polycondensation reaction using raw material monomers of amorphous polyester resin is followed by step (B) of addition polymerization reaction using raw material monomers of styrenic resin and bireactive monomers. In this method, Step (A) is performed under reaction temperature conditions suitable for polycondensation reaction, the reaction temperature is lowered, and step (B) is performed under temperature conditions suitable for addition polymerization reaction. It is preferable that the raw material monomer of the styrenic resin and the bireactive monomer are added to the reaction system at a temperature suitable for the addition polymerization reaction. The bireactive monomer undergoes an addition polymerization reaction and also reacts with the amorphous polyester resin.
After step (B), the reaction temperature is raised again, and if necessary, a raw material monomer of trivalent or higher amorphous polyester resin that will serve as a crosslinking agent is added to the reaction system, and the polycondensation reaction of step (A) is completed. It is possible to further proceed with the reaction with monomers or bireactive monomers.

(ii) A method in which step (A) of a polycondensation reaction using a raw material monomer of an amorphous polyester resin is performed after step (B) of an addition polymerization reaction using a raw material monomer of a styrenic resin and a bireactive monomer. Step (B) is performed under reaction temperature conditions suitable for an addition polymerization reaction, the reaction temperature is raised, and the polycondensation reaction of step (A) is performed under temperature conditions suitable for a polycondensation reaction. Amphoreactive monomers participate in polycondensation reactions as well as addition polymerization reactions.
The raw material monomer for the amorphous polyester resin may be present in the reaction system during the addition polymerization reaction, or may be added to the reaction system under temperature conditions suitable for the polycondensation reaction. In the former case, the progress of the polycondensation reaction can be controlled by adding an esterification catalyst at a temperature suitable for the polycondensation reaction.

(iii) Conditions in which the step (A) of the polycondensation reaction using the raw material monomer of the amorphous polyester resin and the step (B) of the addition polymerization reaction using the raw material monomer of the styrene resin and the bireactive monomer proceed in parallel. In this method, step (A) and step (B) are carried out in parallel under reaction temperature conditions suitable for addition polymerization reaction, and the reaction temperature is raised to maintain temperature conditions suitable for polycondensation reaction. Below, it is preferable to further perform the polycondensation reaction of step (A) by adding to the polymerization system a raw material monomer of an amorphous polyester resin having a valence of 3 or more, which will serve as a crosslinking agent, if necessary. At this time, under temperature conditions suitable for the polycondensation reaction, a radical polymerization inhibitor may be added to allow only the polycondensation reaction to proceed. Amphoreactive monomers participate in polycondensation reactions as well as addition polymerization reactions.

In the method (i) above, a prepolymerized amorphous polyester resin may be used instead of the step (A) of performing a polycondensation reaction. In the method (iii) above, when proceeding in parallel with step (A) and step (B), the mixture containing the raw material monomer of the amorphous polyester resin contains the raw material monomer of the styrenic resin. The reaction can also be carried out by dropping the mixture.

The above methods (i) to (iii) are preferably carried out in the same container.

The mass ratio of styrene resin and amorphous polyester resin in the composite resin (styrene resin/amorphous polyester resin) is preferably 3/97 or more, more preferably 7/97 from the viewpoint of fog suppression and durability. 93 or more, more preferably 10/90 or more, and preferably 45/55 or less, more preferably 40/60 or less, even more preferably 35/65 or less, even more preferably 30/70 or less, even more preferably 25 /75 or less. In addition, in the above calculation, the mass of the polyester resin is the total amount of the raw material monomer and bireactive monomer of the polyester resin used. Further, the amount of styrene resin is the total amount of the raw material monomer of the styrene resin and the polymerization initiator.

From the viewpoint of durability, the softening point of the amorphous polyester resin or amorphous composite resin is preferably 80°C or higher, more preferably 90°C or higher, and still more preferably 100°C or higher, and From this point of view, the temperature is preferably 160°C or lower, more preferably 155°C or lower, even more preferably 150°C or lower.

From the viewpoint of durability, the glass transition temperature of the amorphous polyester resin or amorphous composite resin is preferably 40°C or higher, more preferably 45°C or higher, and even more preferably 50°C or higher, and low-temperature fixability From this viewpoint, the temperature is preferably 75°C or lower, more preferably 70°C or lower, and still more preferably 65°C or lower.

From the viewpoint of durability, the acid value of the amorphous polyester resin or amorphous composite resin is preferably 1 mgKOH/g or more, more preferably 2 mgKOH/g or more, even more preferably 3 mgKOH/g or more, and preferably is 40 mgKOH/g or less, more preferably 30 mgKOH/g or less, even more preferably 20 mgKOH/g or less, even more preferably 10 mgKOH/g or less.

The crystalline polyester resin is preferably a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

Examples of aliphatic diols include 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, etc. In particular, from the viewpoint of increasing the crystallinity of the composite resin and improving the low-temperature fixability, α,ω-linear alkanediol is preferable, and one selected from 1,10-decanediol and 1,12-dodecanediol. Or two types are more preferable, and 1,10-decanediol is even more preferable.

The number of carbon atoms in the aliphatic diol contained in the alcohol component of the crystalline polyester resin is preferably 4 or more, more preferably 9 or more, still more preferably 10 or more, and preferably 14 or less, from the viewpoint of heat-resistant storage stability. , more preferably 12 or less.

The content of the aliphatic diol is preferably 70 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more in the alcohol component, from the viewpoint of increasing the crystallinity of the resin and improving the low-temperature fixability. , more preferably substantially 100 mol%, still more preferably 100 mol%.

The alcohol component may contain polyhydric alcohols other than aliphatic diols, such as aromatic diols such as alkylene oxide adducts of bisphenol A; glycerin, pentaerythritol, trimethylolpropane, sorbitol, and 1,4-sorbitan. Examples include alcohols with a valence of 3 or more.

Examples of aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, and aliphatic hydrocarbon groups having 1 to 30 carbon atoms. Examples include substituted succinic acid, azelaic acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid, and one or two types selected from sebacic acid and dodecanedioic acid from the viewpoint of improving the low-temperature fixing properties of the toner. is preferred, and sebacic acid is more preferred. Note that the dicarboxylic acid compound refers to dicarboxylic acid, its anhydride, and its alkyl ester having 1 or more and 3 or less carbon atoms, and among these, dicarboxylic acid is preferred. Further, the number of carbon atoms in the aliphatic dicarboxylic acid compound described below is the number of carbon atoms including the dicarboxylic acid moiety, and does not include the alkyl ester moiety.

The number of carbon atoms in the aliphatic dicarboxylic acid compound contained in the carboxylic acid component is preferably 4 or more, more preferably 9 or more, and still more preferably 10 or more from the viewpoint of low-temperature fixability, and from the viewpoint of durability. , preferably 14 or less, more preferably 12 or less, and 10 is particularly preferred.

The content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is preferably 70 mol% or more, more preferably 90 mol% or more, and even more preferably It is 95 mol% or more, more preferably substantially 100 mol%, even more preferably 100 mol%.

The carboxylic acid component may contain polyhydric carboxylic acid compounds other than aliphatic dicarboxylic acid compounds, such as aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, and alicyclic acids such as cyclohexanedicarboxylic acid. Trivalent or higher aromatic carboxylic acids such as dicarboxylic acid, trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, acid anhydrides thereof, alkyl esters having 1 or more and 3 or less carbon atoms, etc. can be mentioned.

Note that the alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate from the viewpoint of adjusting the molecular weight and softening point of the polyester resin.

The equivalent ratio of the carboxylic acid component to the alcohol component (COOH group/OH group) in the crystalline polyester resin is preferably 0.7 or more, more preferably 0.85 or more, from the viewpoint of adjusting the softening point of the composite resin, and It is preferably 1.1 or less, more preferably 1.05 or less.

The polycondensation reaction of raw material monomers for crystalline polyester resin is carried out in an inert gas atmosphere, if necessary, in the presence of an esterification catalyst, a polymerization inhibitor, etc., preferably at a temperature of 130°C or higher and 230°C or lower. be able to.

As the crystalline composite resin, a composite resin containing the crystalline polyester resin and a styrene resin is preferable.

The raw material monomers for the styrene resin include the same raw material monomers as those for the amorphous composite resin.

The method for producing the bireactive monomer and the crystalline composite resin is also the same as that for the amorphous composite resin.

The softening point of the crystalline polyester resin or crystalline composite resin is preferably 70°C or higher, more preferably 80°C or higher, and even more preferably 85°C or higher from the viewpoint of durability, and from the viewpoint of low-temperature fixability. , preferably 120°C or lower, more preferably 110°C or lower, even more preferably 100°C or lower.

The melting point of the crystalline polyester resin or crystalline composite resin is preferably 115°C, more preferably 110°C or lower, even more preferably 105°C or lower, even more preferably 100°C or lower, and even more preferably 95°C, from the viewpoint of low-temperature fixability. ℃ or lower, and from the viewpoint of durability, preferably 70℃ or higher, more preferably 75℃ or higher.

When containing a crystalline resin, the mass ratio of the amorphous resin to the crystalline resin (amorphous resin/crystalline resin) is preferably 70/30 or more, more preferably 75/25 from the viewpoint of durability. Above, it is more preferably 80/20 or more, and from the viewpoint of low-temperature fixability, it is preferably 97/3 or less, more preferably 95/5 or less.

The content of the binder resin in the toner is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 100% by mass or more. %, more preferably 98% by mass or less, even more preferably 95% by mass or less.

In addition to the binder resin and magnesium aluminate metasilicate, the toner of the present invention includes reinforcing fillers such as a colorant, a release agent, a charge control agent, a magnetic powder, a fluidity improver, a conductivity modifier, and a fibrous material. Additives such as agents, antioxidants, and cleaning performance improvers may also be used.

As the colorant, dyes, pigments, magnetic substances, etc. that are used as colorants for toners can be used. For example, carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow. etc. Note that in the present invention, the toner may be either a black toner or a color toner.

The content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, based on 100 parts by mass of the binder resin, from the viewpoint of improving the image density and low-temperature fixability of the toner. Preferably it is 40 parts by mass or less, more preferably 10 parts by mass or less.

As mold release agents, hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, Sasol wax, and their oxides; carnauba wax, montan Waxes and their deoxidized waxes, ester waxes such as fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc., can be mentioned, and these can be used alone or in combination of two or more.

The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of toner transferability, and preferably 160°C or lower, more preferably 150°C from the viewpoint of low-temperature fixability. It is as follows.

The content of the release agent is preferably 0.5 parts by mass or more, and more preferably 0.5 parts by mass or more based on 100 parts by mass of the binder resin, from the viewpoints of low-temperature fixability and offset resistance of the toner and dispersibility in the binder resin. The amount is preferably 1 part by weight or more, more preferably 1.5 parts by weight or more, and preferably 10 parts by weight or less, more preferably 8 parts by weight or less, and even more preferably 7 parts by weight or less.

The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.

Examples of positively chargeable charge control agents include nigrosine dyes, such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron N-01", "Bontron N-04", and "Bontron N-07". ", "Bontron N-09", "Bontron N-11" (manufactured by Orient Chemical Industry Co., Ltd.), etc.; triphenylmethane dyes containing tertiary amine as a side chain, quaternary ammonium salt compounds, e.g. "Bontron P-51" (manufactured by Orient Chemical Co., Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant), etc.; Polyamine resins, such as "AFP-B" (manufactured by Orient Chemical Co., Ltd.) Imidazole derivatives, such as "PLZ-2001", "PLZ-8001" (manufactured by Shikoku Kasei Co., Ltd.), etc.; Styrene-acrylic resins, such as "FCA-701PT" (manufactured by Fujikura Kasei Co., Ltd.) ), etc.

In addition, as the negatively chargeable charge control agent, metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", "Bontron S-36" are used. ” (manufactured by Orient Chemical Industry Co., Ltd.), “Eizenspiron Black TRH”, “T-77” (manufactured by Hodogaya Chemical Industry Co., Ltd.), etc.; metal compounds of benzylic acid compounds, such as “LR- 147", "LR-297" (manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds, such as "Bontron E-81", "Bontron E-84", "Bontron E-88", " "Bontron E-304" (manufactured by Orient Chemical Industry Co., Ltd.), "TN-105" (manufactured by Hodogaya Chemical Industry Co., Ltd.), etc.; Copper phthalocyanine dye; Quaternary ammonium salt, such as "COPY CHARGE NX VP434" (manufactured by Clariant), nitroimidazole derivatives, and organometallic compounds.

From the viewpoint of charging stability of the toner, the content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass, based on 100 parts by mass of the binder resin. parts by weight or less, more preferably 5 parts by weight or less, still more preferably 3 parts by weight or less, still more preferably 2 parts by weight or less.

The toner of the present invention may be a toner obtained by any known method such as a melt-kneading method, an emulsion phase inversion method, or a polymerization method. Preference is given to pulverized toners. In the case of pulverized toner produced by the melt-kneading method, for example, raw materials such as a binder resin, magnesium metasilicate aluminate, and if necessary, a colorant, a release agent, a charge control agent, etc. are uniformly mixed with a mixer such as a Henschel mixer. After mixing, the mixture can be produced by melt-kneading in a closed kneader, single-screw or twin-screw extruder, open-roll kneader, etc., followed by cooling, pulverization, and classification.

It is preferable to use an external additive in the toner of the present invention in order to improve transferability. Examples of external additives include inorganic particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic particles such as resin particles such as melamine resin particles and polytetrafluoroethylene resin particles. The above may be used in combination. Among these, silica is preferred, and from the viewpoint of toner transferability, hydrophobic silica that has been subjected to hydrophobic treatment is more preferred.

Hydrophobizing agents for making the surface of silica particles hydrophobic include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), methyltriethoxysilane, etc. It will be done.

The average particle diameter of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and preferably 250 nm or less, more preferably 200 nm or less, and Preferably it is 150 nm or less, more preferably 90 nm or less.

The content of the external additive is preferably 0.05 part by mass or more, more preferably 0.1 part by mass, based on 100 parts by mass of the toner before being treated with the external additive, from the viewpoint of toner chargeability, fluidity, and transferability. parts or more, more preferably 0.3 parts by mass or more, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

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

The toner of the present invention can be used as a toner for one-component development or as a two-component developer by mixing with a carrier, but by using it as a toner for non-magnetic one-component development, the effect of fine line reproducibility is more pronounced. can be demonstrated.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples in any way. The physical properties of the resin etc. were measured by the following method.

[Softening point of resin]
Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample was heated at a heating rate of 6°C/min while applying a load of 1.96 MPa with a plunger, and the sample was 1 mm in diameter and 1 mm in length. extrude from the nozzle. Plot the fall of the plunger of the flow tester against the temperature, and take the temperature at which half of the sample flows out as the softening point.

[Maximum peak temperature of endothermic resin]
Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, and the temperature was lowered from room temperature (25°C) at a rate of 10°C. Cool to 0°C at /min and maintain at 0°C for 1 minute. Then, measure at a heating rate of 10°C/min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area is defined as the maximum endothermic peak temperature.

[Glass transition temperature of resin]
Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, heated to 200°C, and from that temperature Cool down to 0℃ at a cooling rate of 10℃/min. Next, the sample is heated at a heating rate of 10°C/min and measured. The temperature at the intersection of the extension line of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising part of the peak to the apex of the peak is defined as the glass transition temperature.

[Acid value of resin]
Measured based on the method of JIS K 0070:1992. However, the measurement solvent should be changed from the JIS K 0070 specified mixed solvent of ethanol and ether to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[Number average particle size of magnesium metasilicate aluminate]
Measure the particle diameter (average value of major axis and minor axis) of 100 particles from a scanning electron microscope (SEM) photograph, and use the average value as the number average particle diameter.

[Melting point of mold release agent]
Using a differential scanning calorimeter (manufactured by T.A. Instruments Japan Co., Ltd., DSC Q20), the temperature was raised to 200°C at a heating rate of 10°C/min, and then from that temperature at a cooling rate of 5°C/min. The sample cooled to -10°C is heated to 180°C at a heating rate of 10°C/min, and the maximum peak temperature of the endotherm observed from the melting endothermic curve obtained there is taken as the melting point of the mold release agent.

[Number average particle size of external additive]
Measure the particle diameter (average value of major axis and minor axis) of 500 particles from a scanning electron microscope (SEM) photograph, and use the average value as the number average particle diameter.

[Toner volume median particle size]
Measuring device: Coulter Multisizer II (manufactured by Beckman Coulter, Inc.)
Aperture diameter: 100μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (manufactured by Beckman Coulter, Inc.)
Electrolyte: Isoton II (manufactured by Beckman Coulter, Inc.)
Dispersion liquid: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (Griffin): 13.6) was dissolved in an electrolytic solution and adjusted to 5% by mass Dispersion conditions: 10 mg of measurement sample in 5 mL of the above dispersion liquid was added and dispersed for 1 minute using an ultrasonic dispersion machine (machine name: US-1 manufactured by SND Co., Ltd., output: 80W), then 25mL of the electrolyte was added, and further dispersed using an ultrasonic dispersion machine. Disperse for 1 minute to prepare a sample dispersion.
Measurement conditions: Add the sample dispersion to 100 mL of the electrolyte to a concentration that allows the particle size of 30,000 particles to be measured in 20 seconds, measure 30,000 particles, and calculate the volume from the particle size distribution. Determine the median particle size (D ₅₀ ).

Manufacturing example 1 of amorphous resin
The raw material monomers other than trimellitic anhydride shown in Table 1 and the esterification catalyst were placed in a 10L four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer, and thermocouple, and heated to 200℃ under a nitrogen atmosphere. The temperature was raised and the reaction was carried out for 6 hours. After further raising the temperature to 210°C, trimellitic anhydride was added and reacted for 1 hour at normal pressure (101.3 kPa), and further reacted at 40 kPa until the desired softening point was reached, resulting in an amorphous polyester resin. (Resin A1) was obtained. Table 1 shows the physical properties of the obtained resin.

Manufacturing example 2 of amorphous resin
The raw material monomers for amorphous polyester resin other than trimellitic acid shown in Table 1 and the esterification catalyst were placed in a 10 L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple, and heated to 230°C. After the reaction was carried out for 12 hours at 8.3 kPa, the reaction was carried out for 1 hour.
Thereafter, the temperature was lowered to 160° C., and a raw material monomer for a styrenic resin, a bireactive monomer, and a polymerization initiator were added dropwise through a dropping funnel over a period of 1 hour. After aging the addition polymerization reaction for 1 hour while maintaining the temperature at 160°C, the temperature was raised to 210°C and the raw material monomer of the styrenic resin was removed at 8.3 kPa for 1 hour.
Furthermore, trimellitic anhydride was added at 210° C., and the reaction was allowed to occur until a desired softening point was reached, thereby obtaining an amorphous composite resin (resin A2). Table 1 shows the physical properties of the obtained resin.

Production example 1 of crystalline resin
The raw material monomers and esterification catalyst shown in Table 2 were placed in a 10 liter four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple, and heated from 130℃ to 200℃ for 10 hours under a nitrogen atmosphere. The temperature was raised at 200° C. and the reaction was carried out at 8 kPa for 1 hour to obtain crystalline polyester resins (resins C1 and C2). Table 2 shows the physical properties of the obtained resin.

Examples 1 to 9 and Comparative Examples 1 and 2
The binder resin and inorganic particles shown in Table 4, the charge control agent "Bontron E-304" (manufactured by Orient Chemical Industry Co., Ltd.) 0.5 part by mass, and the colorant "ECB-301" (manufactured by Dainichiseika Chemical Industry Co., Ltd.) , 4.0 parts by mass of phthalocyanine blue (C.I. pigment blue 15:3), and 2.5 parts by mass of mold release agent "WEP-9" (manufactured by NOF Corporation, ester wax, melting point: 72°C), Henschel. After mixing for 1 minute using a mixer, the mixture was melt-kneaded under the conditions shown below.

A co-rotating twin-screw extruder PCM-30 (manufactured by Ikegai Co., Ltd., shaft diameter 2.9 cm, shaft cross-sectional area 7.06 cm ² ) was used. The operating conditions are: barrel temperature set at 100℃, shaft rotation speed at 200 r/min (circumferential speed of shaft rotation at 0.30 m/sec), and mixture supply rate at 10 kg/h (mixture supply amount per unit cross-sectional area of the shaft at 1.42 kg/h).・cm ² ).

The obtained resin kneaded product was cooled and coarsely pulverized using a pulverizer "Rotoplex" (manufactured by Hosokawa Micron Co., Ltd.), and a coarsely pulverized product with a volume particle size of 2 mm or less was obtained using a sieve with an opening of 2 mm. . The obtained coarsely pulverized material was finely pulverized using a DS2 type air classifier (collision plate type, manufactured by Nippon Pneumatic Industries Co., Ltd.) by adjusting the pulverizing pressure so that the volume median particle size was 7.0 μm. went. The obtained finely ground material was classified using a DSX2 type air classifier (manufactured by Nippon Pneumatic Industries Co., Ltd.) by adjusting the static pressure (internal pressure) so that the volume median particle size was 7.5 μm. to obtain toner particles.

100 parts by mass of the obtained toner particles, 0.5 parts by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, number average particle diameter: 16 nm) as external additives, and hydrophobic silica 1.0 parts by mass of "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: silicone oil, number average particle size: 40 nm) was added to the Henschel mixer (manufactured by Nippon Coke Industry Co., Ltd.) at 2100 r/min. A toner was obtained by mixing for 3 minutes at a speed of 29 m/sec).

Table 3 shows details of the inorganic particles used in Examples and Comparative Examples.

Test example [fine line reproducibility]
The toner was mounted on a non-magnetic single-component developing device "COREFIDO C530dn" (manufactured by Oki Data Co., Ltd.) and stored for 5 days at 40°C and 85% humidity. After storage, a 2dot/3space/horizontal line pattern was printed on one sheet in an environment of 25°C and 50% humidity, and the reproducibility of the 2dot line was visually confirmed, and the fine line reproducibility was evaluated according to the following evaluation criteria. The results are shown in Table 4.
〔Evaluation criteria〕
A: There are 8 or less breaks in the 2 dot line (1 line/cm).
B: There are 9 to 16 breaks in the 2 dot line (1 line/cm).
C: There are 17 to 24 breaks in the 2 dot line (1 line/cm).
D: There are 25 or more breaks in the 2 dot line (1 line/cm).

From the above results, it can be seen that the toners of Examples 1 to 9 have excellent fine line reproducibility compared to Comparative Example 1, which did not use inorganic particles, and Comparative Example 2, which used alumina as inorganic particles. .

The electrophotographic toner of the present invention is suitably used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing, and the like.

Claims (4)

An electrophotographic toner containing a binder resin and magnesium aluminometasilicate , wherein the magnesium aluminate metasilicate is internally added to toner particles . 2. The electrophotographic toner according to claim 1, wherein the content of magnesium metasilicate aluminate is 0.1 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the binder resin. 3. The electrophotographic toner according to claim 1, wherein the number average particle size of the magnesium metasilicate aluminate is 0.005 μm or more and 0.2 μm or less. 4. The electrophotographic toner according to claim 1, wherein the binder resin contains a polyester resin.