JPH0314344B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrophotographic toner, and more particularly to a dry electrophotographic toner that has excellent fixing properties and offset resistance in heat-pressure fixing.

(Prior Art) Toners for developing electrical latent images or magnetic latent images have traditionally been made of a binder resin such as polystyrene, a coloring agent such as carbon black, and if necessary, a charge control agent or other additives. Generally, the product is melt-kneaded, crushed, and classified.

The most common method for fixing a toner image on an image support such as paper developed with toner is a thermal fixing method, and among these, a hot roll fixing method is the most common.

In this hot roll fixing, the roll is generally heated to 150 to 200[deg.] C., but in order to save thermal energy, it is desirable to be able to fix at a lower temperature. Also, for high-speed copying, roll
Even when heated to 150 to 200°C, the amount of heat supplied to the toner on the fixing image per unit time is small and sufficient fixing becomes difficult, so it is desirable to be able to fix with a smaller amount of heat. It will be done.

As a method for solving these problems, the present inventors have discovered that it is sufficient to add a higher fatty acid amide to the toner. However, it has been found that although the fixing properties are improved when this is added, the offset resistance is significantly inferior.

Note that JP-A-56-87051 states that adding higher fatty acid amide to a toner as an offset preventive agent improves the offset resistance of the toner, but as will be explained later, at least In the case of the present invention, no such effect was observed.

(Problems to be Solved by the Invention) The present invention simultaneously improves both fixing properties and offset resistance in hot roll fixing.

(Means for Solving the Problems) The present invention provides: (A) Styrene, styrene derivatives and/or methacrylic acid alkyl esters in the presence of a melt of 3 to 80 parts by weight of a higher fatty acid amide having a melting point of 60 to 150°C. Polymerizable vinyl monomers mainly composed of 97-20
A resin composition obtained by polymerizing 5 to 80 parts by weight while dropping parts by weight, and (B) a polymerizable vinyl monomer containing styrene, a styrene derivative, or an alkyl methacrylate as a main component. This invention relates to an electrophotographic toner containing 95 to 20 parts by weight of a high molecular weight vinyl polymer.

The above-mentioned higher fatty acid amides are amides of higher fatty acids such as oleic acid, stearic acid, palmitic acid, lauric acid, behenic acid, ricinoleic acid, erucic acid, and montanic acid, and have a melting point of 60 to 150°C.

Examples of the polymerizable vinyl monomer used in the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, and p-n-butylstyrene. , p-tert-butylstyrene, p-n
-hexylstyrene, p-n octylstyrene,
Styrene and its derivatives such as p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, n-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, Among methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate. One or more types are used as the main component. Other polymerizable vinyl monomers that can be used in combination with these include ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide,
Vinyl halides such as vinyl fluoride, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate , n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, α-
Acrylic acid alkyl esters such as methyl chloroacrylate or derivatives thereof, acrylic acid aromatic esters such as phenyl acrylate, methacrylic acid aromatic esters such as phenyl methacrylate, acrylic acids such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, etc. dialkylaminoalkyl esters of methacrylic acid, such as dialkylaminoalkyl esters, dimethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate;
Hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, hydroxyalkyl methacrylates having similar hydroxyalkyl groups, monoacrylates of polyhydric alcohols such as glycerin and trimethylolpropane, or α-methylene aliphatic monocarboxylic acid esters such as monomethacrylate, and other derivatives of acrylic acid or methacrylic acid such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, and in some cases acrylic acid, methacrylic acid, and maleic acid. Acids such as fumaric acid can also be used. Also, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone, N
-vinylpyrrole, N-vinylcarbazole, N
-N-vinyl compounds such as vinyl indole and N-vinylpyrrolidone, vinylnaphthalene salts, etc. can be used singly or in combination of two or more. Furthermore, as the other polymerizable vinyl monomers mentioned above,
It is also possible to partially use a compound having two or more polymerizable double bonds that serves as a crosslinking agent. For example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and their derivatives, diethylene carboxylic acid esters such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol triacrylate, trimethylolpropane triacrylate, N,N divinyl All divinyl compounds such as aniline, divinyl ether, divinyl sulfite, and compounds having three or more vinyl groups can be used alone or as a mixture. The amount of crosslinking agent used is 0 to 100% based on the total amount of polymerizable vinyl monomers.
20% by weight is preferred, particularly 0-5% by weight.

The polymerizable vinyl monomer is polymerized by dropping the polymerizable vinyl monomer dropwise in the presence of the melt of the component (A). The melt of component (A) has a function as a solvent, and in this case, it can be carried out in the same manner as ordinary solution polymerization. However, if the amount of component (A) is small, it should be called bulk polymerization of polymerizable vinyl monomers. The polymerization temperature is the temperature at which component (A) melts, and is preferably 120 to 180°C so that the melt can function sufficiently as a solvent. In addition, the polymerizable vinyl monomer is mixed with a radical polymerization initiator,
It is preferable to continuously add the component (A) dropwise into the melt over a period of 2 hours or more in order to prevent a rapid drop in the temperature of the reaction system and to prevent rapid heat generation due to rapid polymerization. After the reaction is completed, the resin composition of the component (A) can be obtained by cooling.

As the radical color initiator, commonly used tertiary butyl hydroperoxide, ditertiary butyl peroxide, 3,
Organic peroxide radical initiators such as 3,5-trimethylcyclohexanone-ditabutyl peroxyketal, cumene hydroperoxide, and benzoyl peroxide; azobis-based radical initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile; A radical initiator is used. Here, the radical initiator used has a half-life of
It is desirable to use one whose temperature for 10 hours is 70 to 150°C. The radical initiator is preferably used in an amount of 0.2 to 5% by weight based on the total amount of polymerizable vinyl monomers.

The above component (B) is a high molecular weight vinyl polymer obtained by polymerizing a polymerizable vinyl monomer containing styrene, a styrene derivative, or a methacrylic acid alkyl ester as a main component. Examples include polystyrene, methacrylic acid alkyl ester polymers, styrene-acrylate copolymers such as styrene-butyl methacrylate copolymers, styrene-butyl acrylate copolymers, and styrene. -Butadiene copolymer, styrene-maleic acid copolymer, styrene-vinyl acetate copolymer, etc. are used.

The high molecular weight vinyl polymer of component (B) preferably has an insoluble content (including swollen polymers) in chloroform of 1 to 50% by weight. To remove the insoluble matter in chloroform, stir a predetermined amount of high molecular weight vinyl polymer in approximately 100 times the weight of chloroform at room temperature for 30 hours, filter through filter paper, and remove the residue on the filter paper at 150°C for 1 hour. This is the result of drying, measuring the weight, and determining the ratio to the above-mentioned predetermined amount.

In addition, in the present invention, in order to further improve the offset resistance, in addition to the above component (A), it is necessary to use
An olefinic polymer having a weight average molecular weight of 1000 or more at 150°C may be used. The olefin polymer is used in an amount of 0 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 3 to 70 parts by weight of component (a) and 97 to 30 parts by weight of the polymerizable monomer. If the amount of olefin polymer increases, the fixing properties will be poor.

As the olefin polymer, a low molecular weight polymer of olefin or a copolymer of olefin and a monomer other than olefin is used. here,
Examples of olefins include ethylene, propylene, and butene-1, and examples of monomers other than olefins include acrylic esters and methacrylic esters. As this low molecular weight olefin polymer, for example, the polyalkylene described in JP-A-55-153944 and the low-molecular-weight olefin copolymer described in JP-A-50-93647 can be used. . The molecular weight is preferably 1,000 to 45,000 in weight average molecular weight (Mw), and these olefin polymers are selected to have a melting point of 60 to 150°C.

The electrophotographic toner according to the present invention includes the above (A) and
In addition to component (B), a colorant or magnetic powder may be contained, and a toner property improver may be contained as an additive, if necessary.

Coloring agents can include pigments or dyes. For example, carbon black, nigrosine dye, oil black, azo oil black,
Lamp black (CI No. 77266), aniline black, black pigments such as iron black, calco oil blue (azoec Blue3), aniline blue (CI No. 50405),
Blue pigments such as ultramarine blue (CI No. 77103), methylene blue chloride (CI No. 52015), phthalocyanine blue (CI No. 74160), navy blue, cobalt blue, alkali blue lake, and fanest sky blue, chrome yellow (CI No.
14090), Quinoline Yellow (CINo.47005), Yellow lead, Mineral First Yellow, Hansa Yellow G, Benzidine Yellow G, Permanent Yellow
Yellow pigments such as NCG, Rose Bengal (CINo.
45435), DuPont Oil Red (CINo.26105),
Orient Oil Red #330 (CINo.60505), Permanent Red 4R, Brilliant Carmine
Red pigments such as 6B, alizarin lake, red lead, red pigment, permanent orange GTR, pyrazolone orange, Vulcan orange, benzidine orange G, indanthrene brilliant orange
Orange pigments such as GK, molybdenum orange, red yellow lead, malachite green oxalate (CI No.
42000), green pigments such as chrome green, pigment green B, and final yellow green G,
Examples include purple pigments such as manganese purple, fast violet B, and methyl violet lake, and white pigments such as titanium oxide, zinc white, and antimony white.

The coloring agent is used in an amount of 0.1 to 50% by weight based on the binder, and the proportion may be determined as appropriate depending on the case, and in some cases, it may be used in an amount exceeding 50% by weight.

The above-mentioned carbon black may be used as grafted carbon in which the above-mentioned polymerizable vinyl monomer is graft-polymerized onto carbon black.

Magnetic powder is used when manufacturing magnetic toners, and it can also serve as a colorant. Preferred magnetic powders include, for example, oxides or compounds of iron such as magnetite or ferrite, or ferromagnetic elements such as nickel and cobalt. These magnetic powders are preferably in powder form with a particle size of 0.01 to 3 μm, and the surface of the magnetic powder may be treated with a resin, a titanium coupling agent, a silane coupling agent, a higher fatty acid metal salt, or the like. These magnetic substances can be contained in an amount of 20 to 80% by weight, preferably 35 to 70% by weight, based on the toner. Less than this amount may be used as a coloring agent.

Examples of toner property improvers include fluidity improvers, cleaning performance improvers, and charge control agents.

As the fluidity improver, silane, oxides of titanium, aluminum, calcium, magnesium, etc., and oxides made hydrophobic with a titanium coupling agent or a silane coupling agent can be used. These are preferably present in the toner in an amount of 0 to 3% by weight.

Examples of the cleaning performance improver include metal salts of higher fatty acids such as zinc stearate, lithium stearate, and magnesium laurate, and aromatic acid esters such as pentaerythritol benzoate. These are preferably added in an amount of 0 to 3% by weight in the toner.

As a charge control agent, Spiron Black TRH,
Spiron Black TPH (all manufactured by Hodogaya Chemical Industry)
Co., Ltd. (trade name), aromatic acid derivatives such as p-fluorobenzoic acid and 2,4-di-t-butylsalicylic acid, and tin compounds such as dibutyltin oxide and dioctyltin oxide. The charge control agent is preferably added to the toner in an amount of 0 to 5% by weight.

The electrophotographic toner according to the present invention has the above-mentioned (A)
It can be obtained by melting and kneading component (B), a colorant or magnetic powder, and, if necessary, a toner property improver, followed by pulverization and, if necessary, classification.

Furthermore, during the polymerization of the above polymerizable vinyl monomer,
Colorants or magnetic powders and optionally toner property enhancers may also be present.

Note that among the toner property improvers, the fluidity improver and the cleaning performance improver are preferably externally added to the product toner afterwards.

The toner for electrophotography according to the present invention is preferably classified and used so that the average particle size is 9 to 15 μm.

The toner for electrophotography according to the present invention can be applied to a cascade development method, a magnetic brush method, a powder cloud method,
It can be applied to development methods such as touch-down development method, jumping method, so-called microtoning method that uses magnetic toner as a carrier, and so-called bipolar and magnetic toner methods that obtain toner charge by frictional charging between magnetic toners. .

(Function) The electrophotographic toner according to the present invention is a resin obtained by dropping a polymerizable vinyl monomer into the melted higher fatty acid amide having a melting point of 60 to 150°C, which is the component (A), and polymerizing it. By using the composition and the above-mentioned high molecular weight vinyl polymer as a binder, the fixing properties and offset resistance are excellent.

Therefore, the amount of the component (A) and the polymerizable vinyl monomer is 3 to 80 parts by weight (preferably 3 to 70 parts by weight).
97 to 20 parts by weight (preferably 97 to 30 parts by weight, particularly preferably 90 to 60 parts by weight) of the latter are used. If the amount of component (A) is too small, the effect of improving fixing properties will be reduced, and if it is too large, melt-kneading of the resin composition and the high molecular weight vinyl polymer will become difficult.

Even if the component (A) is melt-kneaded with the high molecular weight vinyl polymer, it is difficult to disperse it in the polymer.
On the other hand, the above resin composition has component (A) uniformly dispersed and has good fixing properties, but is poor in offset resistance.

In the present invention, the above-mentioned resin composition and the above-mentioned high molecular weight vinyl polymer are used as binders, but both can be easily melted and kneaded, and therefore the high molecular weight polymer also contains component (A). It is well dispersed and has good fixing properties, but surprisingly also has excellent offset resistance.

For this purpose, the resin composition and the high molecular weight vinyl polymer are combined in an amount of 5 to 80 parts by weight (preferably
20-60 parts by weight), 95-20 parts by weight (preferably 80-40 parts by weight) of the latter are used. If the amount of the resin composition is too small, the fixing properties will be poor, and if it is too large, the offset resistance will be poor.

Component (A) is preferably contained in the binder in an amount of 1 to 40% by weight, particularly preferably 3 to 20% by weight.

In addition, in the present invention, the use of the above-mentioned component (A) is combined with the use of styrene, its derivative and/or methacrylic acid alkyl ester as a polymerizable vinyl monomer, and further, in these combinations, (B)
The combination of the use of polymers or copolymers of styrene, derivatives thereof, and alkyl methacrylates as the component high molecular weight vinyl polymers is particularly effective.

(Example) Next, the present invention will be explained in detail with reference to Examples. Hereinafter, "parts" represent "parts by weight."

Example 1 (A) In a separable flask equipped with a stirrer, a condenser, a dropping funnel, and a gas inlet tube, a 7:3 mixture of stearic acid amide and palmitic acid amide was added.
(weight ratio) 30 parts of a mixture (Amide AP-1 manufactured by Nippon Kasei Co., Ltd.) was weighed out and heated to 150° C. to melt it. While stirring under a stream of N ₂ gas, a mixture of 56 parts of styrene, 24 parts of butyl methacrylate, and 0.8 parts of ditertiary butyl peroxide was added dropwise over 2 hours. Subsequently, the mixture was heated and stirred at 150°C for 2 hours to complete the polymerization reaction. The reaction product was taken out from the flask at 150°C, cooled and solidified to obtain a resin composition.

(B) Tonerization and unfixed image creation 50 parts of the resin composition obtained in (A), styrene-butyl methacrylate-divinylbenzene (69.8/30/
0.2: weight ratio) copolymer (chloroform insoluble content: 30
(% by weight), 5 parts of nigrosine dye, and 5 parts of carbon black were kneaded using a Conida kneader, and then pulverized to obtain an electrophotographic toner having an average particle size of about 12 μm.

Five parts of this electrophotographic toner were mixed with 95 parts of iron powder carrier having an average particle size of 150 microns and used as a developer to develop a negative electrostatic image to obtain an unfixed image on paper.

(C) Toner evaluation (a) Caking resistance The toner obtained in (B) was placed in a glass shear plate for 5 mm.
It was placed on a thick layer and stored in a constant temperature bath at 50°C for 24 hours. When this was sieved through a 100 mesh wire mesh, it was 95% by weight.
The above has passed.

(b) Fixability and offset properties The unfixed image obtained in (B) was fixed at a linear pressure of 10 kg and a linear speed of 30
It was fixed by passing it through a Teflon heat roll at m/min. When the temperature was varied by 10°C in the range of 80 to 220°C, the fixing was good at 120°C.
Also, offset occurred for the first time at 200°C.

The fixing property was determined to be good when cellophane tape (manufactured by Nichiban Co., Ltd.) was pressed onto the black solid image, and it was peeled off slowly and no toner was generated.

Example 2 Weighed 20 parts of oleic acid amide (Diamic O, trade name of Nippon Kasei Co., Ltd.) into a separable flask,
It was heated to 150°C to melt it. A mixture of 60 parts of styrene, 20 parts of ethyl methacrylate, and 0.9 parts of ditertiary butyl peroxide was added dropwise thereto over 3 hours while stirring under a stream of N ₂ gas.

Subsequently, the mixture was heated and stirred at 150°C for 2 hours to complete the polymerization reaction. The reaction product was cooled and solidified in the same manner as in Example 1 to obtain a resin composition.

45 parts by weight of this resin composition, styrene-butyl acrylate (80/20: weight ratio) copolymer (weight average molecular weight approximately 120,000, chloroform insoluble content 0% by weight)
45 parts, nigrosine dye 5 parts, carbon black 5 parts
A toner was obtained from the sample in the same manner as in Example 1(B) to obtain an unfixed image.

This toner and unfixed image were tested in the same manner as in Example 1(C), and the following results were obtained.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 100°C (c) Offset property: Offset occurs at 160°C Example 3 In Example 1, the ratio of the resin composition and the styrene-butyl methacrylate-divinylbenzene copolymer was A toner was made in the same manner as in Example 1 except that 20 parts and 80 parts were used, and evaluation was performed to obtain the following results.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 140°C (c) Offset property: No offset occurred even at 220°C Example 4 In Example 1, a combination of the resin composition and the styrene-butyl methacrylate-divinylbenzene copolymer was used. Toners were prepared in the same manner as in Example 1 except that the ratios were changed to 60 parts and 40 parts, and evaluation was performed to obtain the following results.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 110°C (c) Offset property: Offset occurs at 160°C Comparative Example 1 In Example 1, the resin was A toner was prepared in the same manner using 100 parts of the composition and evaluated, and the following results were obtained.

(a) Caking property: passing through 100 meshes, approximately 70% by weight (b) Fixing property: Good fixing at 100°C (c) Offset property: Offset occurs at 100°C Comparative Example 2 In Example 1, the resin composition was Instead, a styrene-butyl methacrylate (70/30) copolymer (weight average molecular weight of about 40,000) was used, and Example 1
A toner was prepared and evaluated in the same manner as above, and the following results were obtained.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 180°C (c) Offset property: Offset occurs at 210°C Comparative example 3 In Example 1, styrene-butyl methacrylate (70/30) was used instead of resin (A). 35 parts of copolymer (weight average molecular weight approximately 40,000) and amide AP-1
An attempt was made to form a toner using 15 parts of the mixture, but due to the slipperiness of Amide AP-1, no stress (shearing force) was applied to the melt, and kneading was not possible.

Example 5 In Example 1, 2 parts out of 30 parts of a 7:3 (weight ratio) mixture of stearic acid amide and palmitic acid amide (Amide AP-1 manufactured by Nippon Kasei) were mixed with low molecular weight polypropylene (Piscol 550P manufactured by Sanyo Chemical). Instead, a resin composition was obtained in the same manner as in Example 1, and a toner was obtained in the same manner as in Example 1.
evaluated.

Example 6 In a separable flask, 18 parts of oleic acid amide (Diamic O, trade name of Nippon Kasei Co., Ltd.) and 2 parts of low molecular weight polyethylene (Hiwax 200P, manufactured by Mitsui Petrochemicals) were weighed and melted by heating to 150°C. .
Add styrene to this while stirring under a stream of _N2 gas.
A mixture of 60 parts of ethyl methacrylate, 20 parts of ethyl methacrylate, and 0.9 parts of ditertiary butyl peroxide was added dropwise over 3 hours.

Subsequently, the mixture was heated and stirred at 150°C for 2 hours to complete the polymerization reaction. The reaction product was cooled and solidified in the same manner as in Example 1 to obtain a resin composition.

In the same manner as in Example 1(B), 45 parts by weight of this resin composition, 45 parts of styrene-butyl acrylate (80/20) copolymer (weight average molecular weight approximately 120,000), 5 parts of nigrosine dye, and 5 parts of carbon black were prepared. This was converted into toner and an unfixed image was obtained.

This toner and unfixed image were tested in the same manner as in Example 1(C), and the following results were obtained.

As a result, (a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 100°C (c) Offset property: Offset occurs at 160°C Example 7 In Example 5, the ratio of the resin composition and the styrene-butyl methacrylate-divinylbenzene copolymer was A toner was prepared in the same manner as in Example 1 except that 20 parts and 80 parts were used, and the following results were obtained.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 140°C. (c) Offset property: No offset occurred even at 220°C. Toners were prepared in the same manner as in Example 1 except that the ratios were changed to 60 parts and 40 parts, and evaluation was performed to obtain the following results.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 110°C (c) Offset property: Offset occurs at 170°C Comparative Example 4 In Example 5, the resin composition was prepared without using the styrene-butyl methacrylate-divinylbenzene copolymer. A toner was prepared in the same manner using 100 copies of the same and evaluated, and the following results were obtained.

(a) Caking property: 100 mesh passes, approximately 70% by weight (b) Fixing property: Good fixing at 100°C (c) Offset property: Offset occurs at 120°C Example 9 (A) Example 5 (A) and A resin composition was obtained in the same manner.

(B) Tonerization and unfixed image creation 50 parts of the resin composition obtained in (A), styrene-butyl methacrylate-divinylbenzene (69.8/30/
0.2) Copolymer (chloroform insoluble content 30% by weight)
50 copies, magnetite (EPT-500 manufactured by Toda Kogyo)
100 parts of nigrosine dye and 5 parts of carbon black were kneaded in a Conida kneader and then ground to obtain a magnetic toner having an average particle size of about 12μ.

This magnetic toner was installed in a copying machine (manufactured by Canon NP-270RE) from which the fixing section had been removed, and an unfixed image was created on paper.

Thereafter, the toner was evaluated in the same manner as in Example 1(C). The results are (a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 120°C (c) Offset property: Offset occurs at 220°C Example 10 18 parts of oleic acid amide (Diamic O, trade name of Nippon Kasei Co., Ltd.) and low molecular weight were placed in a separable flask. Two parts of polyethylene (Hiwax 200P manufactured by Mitsui Petrochemicals) was weighed and heated to 150°C to melt it.
Add styrene to this while stirring under a stream of _N2 gas.
A mixture of 60 parts of ethyl methacrylate, 20 parts of ethyl methacrylate, and 0.9 parts of ditertiary butyl peroxide was added dropwise over 3 hours.

Subsequently, the mixture was heated and stirred at 150°C for 2 hours to complete the polymerization reaction. The reaction product was cooled and solidified in the same manner as in Example 1 to obtain a resin composition.

45 parts by weight of this resin composition, 45 parts of styrene-butyl acrylate (80/20) copolymer (weight average molecular weight approximately 120,000), 100 parts of magnetite (EPT-500 manufactured by Toda Kogyo), 5 parts of nigrosine dye, carbon black. Five copies were converted into toner in the same manner as in Example 1(B) to obtain an unfixed image.

This toner and unfixed image were tested in the same manner as in Example 1(C), and the following results were obtained.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 110°C (c) Offset property: Offset occurs at 180°C Example 11 In Example 9, the ratio of the resin composition and the styrene-butyl methacrylate-divinylbenzene copolymer was Instead of using 20 parts and 80 parts, toners were prepared in the same manner as in Example 9 and evaluated, and the following results were obtained.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 140°C (c) Offset property: No offset occurred even at 220°C Toners were prepared in the same manner as in Example 9 except that the ratios were changed to 60 parts and 40 parts, and the following results were obtained.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 110°C (c) Offset property: Offset occurs at 170°C Comparative Example 5 In Example 9, the resin was A toner was prepared in the same manner using 100 parts of the composition and evaluated, and the following results were obtained.

(a) Caking property: Passed through 100 meshes, approximately 70% by weight (b) Fixing property: Good fixing at 100°C (c) Offset property: Offset occurred at 120°C Comparative Example 6 In Example 9, the resin composition Instead, a styrene-butyl methacrylate (70/30) copolymer (weight average molecular weight approximately 40,000, chloroform-insoluble content 0% by weight) was used to form a toner in the same manner as in Example 1, and the evaluation was performed to obtain the following results. I got it.

(a) Caking property: 100 mesh passes, 95% by weight
Above (b) Fixing property: Good fixing at 190°C (c) Offset property: Offset occurs at 210°C Comparative Example 7 In Example 9, styrene-butyl methacrylate (70/30) was used instead of resin (A). 35 parts of copolymer (weight average molecular weight approximately 40,000) and amide AP-1
An attempt was made to form a toner using 15 parts of the mixture, but due to the slipperiness of Amide AP-1, stress (shearing force) was not applied to the melt and kneading was not possible.

(Effects of the Invention) The toner according to the present invention has excellent fixing properties and offset resistance.

Claims (1)

[Scope of Claims] 1 (A) Higher fatty acid amide 3 having a melting point of 60 to 150°C
In the presence of ~80 parts by weight of the melt, a polymerizable vinyl monomer mainly composed of styrene, styrene derivatives and/or methacrylic acid alkyl esters.
5 to 80 parts by weight of a resin composition obtained by polymerizing while dropping 97 to 20 parts by weight, and (B) a polymerizable vinyl monomer containing styrene, a styrene derivative, or an alkyl methacrylate as a main component. An electrophotographic toner containing 95 to 20 parts by weight of a high molecular weight vinyl polymer obtained by. 2. The electrophotographic toner according to claim 1, wherein the high molecular weight vinyl polymer as component (B) has a chloroform-insoluble content of 1 to 50% by weight.