JPH0798518A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To maintain a moderate extent of electrostatic charge and to stably give high image quality independent of the environment by using a bonding resin consisting of a condensation-polymerized resin forming a continuous phase and an addition-polymerized resin forming a dispersed phase which accounts for a specified range in a cross section of the bonding resin. CONSTITUTION:A bonding resin consisting of a condensation-polymerized resin forming a continuous phase and an addition-polymerized resin forming a dispersed phase is used. A part of the dispersed phase having <=2mum diameter in a cross section of t.he bonding resin accounts for >=90% of the total cross-sectional area of the dispersed phase. When a part of the dispersed phase having >2mum diameter accounts for >10% of the total cross-sectional area, the bonding resin is not uniform and the electrostatic charge stability of a toner using the resin is deteriorated. The condensation-polymerized resin is preferably polyester or polyester-polyamide. The polyester is obtd. by condensation-polymerizing alcohol and carboxylic acid or its anhydride as starting monomers. The addition- polymerized resin is preferably vinyl resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for electrophotography, which maintains an appropriate amount of charge and stably supplies high image quality which is not affected by the environment.

[0002]

2. Description of the Related Art Conventional electrophotographic methods include US Pat. Nos. 2,297,691 and 235780.
As described in the specification of No. 9, etc., an electrically latent image is formed by uniformly charging the photoconductive insulating layer, then exposing the layer, and dissipating the charge in the exposed portion. Then, the latent image is made into a visible image by adhering fine powder having a colored charge called toner (developing step), and the obtained visible image is transferred to a transfer material such as transfer paper. After that (transferring step), permanent fixing is carried out by heating, pressure or any other suitable fixing method (fixing step). As described above, the toner must have the functions required not only in the developing step but also in the transfer step and the fixing step.

Of these, in the fixing step, a contact heat fixing method such as heat roller fixing and a non-contact heat fixing method such as oven fixing are used. The contact method is characterized by high thermal efficiency and can lower the temperature applied to the fixing device as compared with the non-contact method, which is effective for energy saving and downsizing of the copying machine. However, in this contact heat fixing method, a so-called offset phenomenon in which toner adheres to the surface of the heating roller and is transferred to the subsequent transfer paper or the like is likely to occur. In order to prevent this phenomenon, the surface of the heat roller is processed with a material having excellent mold release property such as fluorine resin, or a mold release agent such as silicone oil is applied to the surface of the heat roller. However, the method using silicone oil or the like is not preferable because the fixing device becomes large and complicated, which may increase the cost and cause troubles.

Conventionally, a vinyl resin represented by a styrene-acrylic copolymer has been used for this kind of toner. In the case of a vinyl resin, it is necessary to increase the softening point and the crosslink density of the resin in order to improve the offset resistance, and this lowers the low temperature fixability. On the contrary, if low temperature fixability is emphasized, problems occur in offset resistance and blocking resistance. Also known is a method of adding paraffin wax, low-molecular-weight polyolefin and the like as an anti-offset agent (JP-A-49-65232 and JP-A-50-).
No. 28840, JP-A No. 50-81342),
In this case, the effect cannot be obtained if the addition amount is small, and if the addition amount is too large, there is a problem that the deterioration of the developer is rapid.

On the other hand, a copying machine is often installed under severe conditions such as high temperature and high humidity and low temperature and low humidity as the versatility increases. It is indispensable to obtain a clear image similar to. Regarding this point, although the vinyl resin has a stable charge amount under high temperature and high humidity and does not deteriorate the image, it causes an increase in the charge amount under low temperature and low humidity, which causes a problem that the image density decreases. Regarding these problems, various proposals have hitherto been made, but they have not been fundamentally solved.

By the way, as the binder resin used in the toner, polyester is used because it has a wide molecular weight distribution and is particularly excellent in offset resistance and low-temperature fixability. Polyester is a resin suitable for providing a low molecular weight component effective for low temperature fixing property. Among them, the acid value is 5
In the toner using polyester with KOHmg / g or more,
Fixing is achieved at a low temperature, offset resistance is also satisfied, and the developer does not deteriorate even after printing hundreds of thousands of sheets. As described above, a polyester having a relatively high acid value has excellent fixability, a long developer life, and stable chargeability at low temperature and low humidity, but the charge amount at high temperature and high humidity varies depending on the formulation at the time of toner production. Such as rising
It lacks environmental stability. In contrast,
A toner using a polyester having an acid value of 5 KOHmg / g or less (Japanese Patent Laid-Open No. 63-148271 etc.) has characteristics that the charging property is not affected by the environment and the developer is not deteriorated. On the other hand, the fixability was not satisfactory.

For this reason, the following method is known in which a polyester resin having an excellent fixing property and a styrene acrylic resin having a smaller variation rate of the charge amount than those under normal temperature and normal humidity are mixed and used under high temperature and high humidity. . For example, the following method may be mentioned. A method of mixing a polyester resin and a styrene acrylic resin (JP-A-49-6931 and JP-A-54-11).
No. 4245, JP-A-57-70523, JP-A-2-161464); A method of chemically bonding a polyester resin and a styrene-acrylic resin (JP-A-56-116043); A method of copolymerizing a vinyl-based monomer (JP-A-57-60339 and JP-A-6-63).
No. 3-279265, JP-A-1-156759, JP-A-2-5073); A method of copolymerizing a vinyl monomer with a polyester resin having a (meth) acryloyl group (JP-A-59-59).
45453); a method of copolymerizing a reactive polyester and a vinyl monomer in the presence of a polyester resin (JP-A-2-29664).
JP-A-2-881); and a method of blocking a polyester resin and a vinyl resin with an ester bond.

However, since the polyester resin and the styrene-acrylic resin are inherently poor in compatibility with each other, when simply mechanically mixing, depending on the mixing ratio, the resin, carbon black and the like may be selected depending on the mixing ratio. Since the dispersion of the additive becomes poor and the chargeability becomes non-uniform, problems such as scumming occur in image evaluation. Further, when the molecular weights of the two types of resins are different, a difference may occur in the melt viscosities of the two types of resin, which makes it difficult to make the dispersed particle size of the resin in the dispersed phase fine, and when the toner is manufactured. The dispersion of the internal additive such as carbon black is very poor, and there arises a problem that the image stability is largely deteriorated. Further, when polymerizing a vinyl monomer with a reactive polyester, there is a problem that the composition is limited in order to prevent gelation.

Further, a toner using a resin composition having a microdomain structure formed of domain particles and a matrix as a binder resin is also known (JP-A-4-366176 and JP-A-4-366854). Gazette). However, since the matrix of these resins is substantially styrene-acrylic resin, the problem of poor fixing inherent to styrene-acrylic resin has not been solved.

Furthermore, the present inventors have developed a technique in which a resin obtained by simultaneously advancing addition polymerization and polycondensation in the same reaction vessel is used as a binder for toner (Japanese Patent Laid-Open No. 142301/1992). A binder having a sea-island structure in which a styrene acrylic resin is dispersed is disclosed as the binder for the toner, but the dispersed particle size is larger than 2 μm. Therefore, although this method can lower the fixing temperature, it is not sufficiently satisfactory in terms of improving the life of the toner.

Therefore, there has been a demand for a binder resin for electrophotography which is excellent in low-temperature fixability and anti-offset property, is excellent in environmental stability such as charge amount and image quality, and is also excellent in durability of a developer.

Therefore, an object of the present invention is to provide an electrophotographic toner which maintains a proper charge amount and stably supplies a high image quality which is not affected by the environment.

[0013]

Under such circumstances, the inventors of the present invention have conducted diligent research and, as a result, have found that a continuous phase of a condensation-polymerized resin and an addition-polymerized resin dispersed in a diameter of 2 μm or less for electrophotography. The present invention has been completed based on the finding that a toner and a developer having excellent low-temperature fixability and anti-offset property can be obtained by using a coating resin without depending on the environment in terms of charge amount and image quality.

That is, the gist of the present invention is (1) in an electrophotographic toner containing at least a binder resin and a colorant, the binder resin forms a disperse phase with a polycondensation resin forming a continuous phase. An electrophotographic toner comprising an addition-polymerized resin and having a diameter of 2 μm or less in the resin cross-section occupying 90% or more of the entire cross-sectional area of the dispersed phase. (2) Addition polymerization of polycondensation-based resin The toner for electrophotography according to (1) above, wherein the weight ratio to the resin is 50/50 to 95/5, and (3) the polycondensation resin is polyester.
The electrophotographic toner according to (1) or (2) above, which is one or more selected from the group consisting of polyester-polyamide and polyamide, and the addition polymerization resin is a vinyl resin, and (4) a vinyl resin. Has a number average molecular weight of 50
The electrophotographic toner according to (3) above, which is 0 to 20000, (5) the electrophotographic toner according to any one of (1) to (4) above, wherein the binder resin has an acid value of less than 20 KOHmg / g. 6) Under the temperature conditions suitable for the addition polymerization reaction, the binder resin is added dropwise to the raw material monomer mixture of the vinyl resin in the mixture of the raw material monomers of polyester, polyester-polyamide or polyamide, in parallel with the addition polymerization reaction. A step of partially carrying out the polycondensation reaction, a step of maintaining the temperature of the obtained mixture under the above conditions to complete only the addition polymerization reaction, and then raising the reaction temperature to raise the degree of polymerization of the polycondensation reaction. The toner for electrophotography according to any one of (1) to (5) above, wherein (7) the raw material monomer of the vinyl resin is styrene or acryl. The toner for electrophotography according to (6) above, which is one or more selected from the group consisting of acid, butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid and butyl methacrylate, (8) polyester, polyester-polyamide. Alternatively, the raw material monomer for the polyamide is one or more acid components selected from the group consisting of terephthalic acid, trimellitic acid, alkenylsuccinic acid, fumaric acid and maleic acid, and an alkylene oxide adduct of bisphenol A, hexamethylenediamine. And the electrophotographic toner according to (6) or (7), which is one or more alcohol or amine components selected from the group consisting of and ε-caprolactam, and (9) the above (1) further containing a wax. (8) The present invention relates to the electrophotographic toner according to any one of the items.

In the electrophotographic toner of the present invention, the polycondensation resin forms a continuous phase, the addition polymerization resin forms a dispersed phase, and the dispersed phase having a diameter of 2 μm or less in the resin cross section is dispersed. It is necessary to occupy 90% or more of the total phase cross-sectional area. Here, the diameter in the resin cross section means the diameter of the dispersed phase (dispersion particle size) measured in the cross section.
Say. If the disperse phase having a diameter of more than 2 μm in the resin cross section exceeds the area ratio of 10%, a uniform binder resin cannot be obtained and the charging stability becomes poor when used as a toner.
Here, the diameter of the dispersed phase and the area ratio of the dispersed phase are 100 to 300 nm for a resin having a diameter of about 0.2 mm with a microtome.
The thin slices obtained by cutting to the thickness of JEOL (for example, JEOL (JEOL Ltd.), "JEM").
-2000 ") and perform image analysis by a well-known method.

Such a dispersion system is prepared, for example, by preliminarily blending a monomer mixture of two polymerization systems of polycondensation polymerization and addition polymerization in the same reactor, and carrying out the two polymerization reactions in parallel (Japanese Patent Laid-Open No. Hei 4). No. 142301), particularly preferably, a monomer capable of conducting both condensation polymerization and addition polymerization is used. Specifically, the dispersion system can be formed by reacting with a monomer having an unsaturated bond and a carboxyl group.

In the present invention, as the polycondensation resin,
Polyester, polyester-polyamide and polyamide are preferred. Among these, the polyester can be obtained by polycondensation of alcohol and carboxylic acid, carboxylic acid anhydride, carboxylic acid ester or the like as a raw material monomer.

Examples of the dihydric alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,
2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis Alkylene oxide adducts of bisphenol A such as (4-hydroxyphenyl) propane and polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol,
1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A and the like can be mentioned.

Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, and 1,4.
-Sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,
4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like can be mentioned. Of these alcohol components,
Preferably, an alkylene oxide adduct of bisphenol A is used. In the present invention, these dihydric alcohol monomers and trihydric or higher polyhydric alcohol monomers may be used alone or in combination of two or more.

The acid component is a carboxylic acid component and is a divalent monomer such as maleic acid, fumaric acid,
Citraconic acid, itaconic acid, glutaconic acid, phthalic acid,
Isophthalic acid, terephthalic acid, succinic acid, adipic acid,
Sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid,
Examples thereof include isooctyl succinic acid, anhydrides of these acids, and lower alkyl esters.

Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid and 1,2,4- Butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-
2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl)
Methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empol trimer acid and their acid anhydrides,
Lower alkyl ester and the like can be mentioned.

In the present invention, among the carboxylic acid components,
Terephthalic acid, alkenylsuccinic acid, trimellitic acid,
Fumaric acid and maleic acid are preferably used. In particular, it is preferable to use a monomer capable of performing both condensation polymerization and addition polymerization, such as fumaric acid, maleic acid, and alkenylsuccinic acid. The content of these carboxylic acid components is 0.5 to 10% by weight, especially 0.5
It is preferably used in a proportion of ˜5% by weight.

Among the raw material monomers forming the polyester polyamide or the amide component in the polyamide obtained by polycondensation, the raw material monomers include, for example, ethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, iminobispropylamine, phenylene. Polyamines such as diamine, xylylenediamine and triethylenetetramine, aminocarboxylic acids such as 6-aminocaproic acid and ε-caprolactam,
Examples thereof include amino alcohols such as propanolamine. Hexamethylenediamine and ε-caprolactam are preferably used.

On the other hand, the addition polymerization resin is preferably a vinyl resin, and it is preferable to use a polymerization initiator such as a peroxide or an azo compound during the polymerization.

Typical monomers used to form vinyl resins include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene,
Styrene or styrene derivatives such as α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-chlorostyrene, vinylnaphthalene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene; Vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl formate and vinyl caproate;
For example, acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, amyl acrylate, cyclohexyl acrylate, n-acrylate. Octyl, isooctyl acrylate, decyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methoxyethyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, acrylic acid 2
-Chloroethyl, phenyl acrylate, α-methyl chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate. , Amyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, decyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, methacryl Ethylenic monocarboxylic acids such as glycidyl acid salt, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and their esters; For example, ethylenic monocarboxylic acid substitution products such as acrylonitrile, methacrylonitrile, and acrylamide; for example, ethylenic dicarboxylic acids such as dimethyl maleate and substitution products thereof; vinyl ketones such as vinyl methyl ketone; vinyl ethers such as vinyl methyl ether. Vinylidene halides such as vinylidene chloride; for example N-vinylpyrrole, N-
Examples thereof include N-vinyl compounds such as vinylpyrrolidone. In the present invention, styrene, acrylic acid, butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid and butyl methacrylate are preferably used.

The polymerization initiator used for producing the vinyl resin is, for example, 2,2'-azobis (2,4-
Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-
Dimethyl valeronitrile, other azo or diazo polymerization initiators, or benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate, cumene hydroperoxide, 2,4-
Examples thereof include peroxide type polymerization initiators such as dichlorobenzoyl peroxide, lauroyl peroxide and dicumyl peroxide.

Two or more kinds of polymerization initiators may be mixed and used for the purpose of controlling the molecular weight and the molecular weight distribution of the polymer or the reaction time. The amount of the polymerization initiator used is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymerized monomer.

Further, a cross-linking agent may be used if necessary, and examples thereof include divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexylene glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-bis (4
-Acryloxydiethoxyphenyl) propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, dibromoneopentyl glycol dimethacrylate, diallyl phthalate, etc. And a combination of two or more thereof can be used. Divinylbenzene and polyethylene glycol dimethacrylate are preferably used.

The amount of these crosslinking agents used is 0.001 to 15% by weight, preferably 0.1 to 15% by weight, based on the vinyl polymerizable monomer.
It is recommended to use ~ 10% by weight. When the amount of these cross-linking agents used is more than 15% by weight, the toner obtained is less likely to be melted by heat, resulting in poor heat fixing property or heat pressure fixing property. When the amount used is less than 0.001% by weight, it is difficult to prevent the offset phenomenon in which a part of the toner adheres to the roller surface without being completely fixed to the paper and is transferred to the next paper during thermal pressure fixing.

In the present invention, the number average molecular weight of the addition polymerization resin is preferably 5,000 to 20,000,
Within this range, the fixability is improved. If it is less than 5,000, the storability of the toner deteriorates, and if it exceeds 20,000, the fixing temperature becomes high, which is not preferable. The molecular weight of the addition polymerization resin can be easily controlled by adjusting the amounts of polymerization initiator and chain transfer agent used and the polymerization temperature.

The polymerization reaction is carried out in parallel with the addition polymerization reaction, for example, by dropping the vinyl monomer raw material monomer mixture into a polyester, polyester-polyamide or polyamide raw material mixture mixture under temperature conditions suitable for the addition polymerization reaction. To partially carry out the polycondensation reaction, to maintain the temperature of the obtained mixture under the above conditions to complete only the addition polymerization reaction, and then to raise the reaction temperature to increase the degree of polymerization of the polycondensation reaction. And the step of increasing the temperature.

Here, the temperature condition suitable for the addition polymerization reaction depends on the kind of the polymerization initiator used, but it is 50 to 1
It is usually carried out in the temperature range of 80 ° C. The optimum temperature range for increasing the polymerization degree of the polycondensation reaction is usually 190 to
270 ° C. As described above, a binder resin in which two kinds of resins are effectively mixed and dispersed can be obtained by a method of allowing two independent reactions to proceed in parallel in a reaction vessel.

The softening point of the obtained binder resin is preferably 95 to 170 ° C., particularly preferably 95 to 150.
The glass transition temperature is preferably 50 to 80 ° C., and particularly preferably 55 to 70 ° C. The softening point and the glass transition temperature of the binder resin can be easily adjusted by adjusting the polymerization initiator and the amount of catalyst in the raw material monomer mixture or selecting the reaction conditions.

In the present invention, since the polycondensation resin is the continuous phase, the weight ratio of the polycondensation resin and the addition polymerization resin or the polycondensation resin monomer to the addition polymerization resin monomer is from 50/50. 95/5, especially 70/3
It is preferably in the range of 0 to 90/10. If the proportion of the addition polymerization resin (or resin monomer) exceeds 50% by weight, the fixability will be poor, and if it is less than 5% by weight, the stability of the image against the environment will be poor, which is not preferable.

The binder resin has an acid value of 20 KOHmg.
/ G is preferable because the toner charge amount does not decrease even under high temperature and high humidity. If the amount is 20 KOHmg / g or more, the charge amount may decrease depending on the toner composition and the type of carrier, which is not preferable.

To produce a toner using a binder resin,
For example, the binder resin, a colorant, and if necessary, a charge control agent, a magnetic material and the like are added. Examples of the colorant used in the present invention include various carbon blacks produced by a thermal black method, an acetylene black method, a channel black method, a lamp black method, etc., and a grafted carbon black obtained by coating the surface of the carbon black with a resin. , Nigrosine dye, Phthalocyanine Blue, Permanent Brown FG, Brilliant Fast Scarlet, Pigment Green B, Rhodamine-B Base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, etc., and mixtures thereof. It is preferable that about 1 to 15 parts by weight is used with respect to 100 parts by weight of the coating resin.

As the charge control agent used as necessary, either positive or negative charge control agents can be used. The specific examples of the positive charge control agent are not particularly limited, and examples thereof include a nigrosine dye "Nigrosine Base E".
"X", "Oil Black BS", "Oil Black S"
O "," Bontron N-01 "," Bontron N-0 "
7 "," Bontron N-11 "(above, manufactured by Orient Chemical Co., Ltd.); triphenylmethane dye containing a tertiary amine as a side chain, quaternary ammonium salt compound, for example," Bontron P-51 "(Orient Chemical) ), Cetyl trimethyl ammonium bromide, "COPY CHARGE PX
VP435 "(manufactured by Hoechst) and the like; polyamine resins such as" AFP-B "(manufactured by Orient Chemical Co.), imidazole derivatives such as" PLZ-2001 "and" PLZ-80 ".
01 ”(above, manufactured by Shikoku Kasei) and the like. Preferably, Bontron N-07 can be used.

Specific examples of the negative charge control agent include:
Without being particularly limited, for example, metal-containing azo dyes such as “Varifast Black 3804” and “Bontron S
-31 "(above, manufactured by Orient Chemical Co., Ltd.)," T-77 "
(Manufactured by Hodogaya Chemical Co., Ltd.), "Bontron S-32", "Bontron S-34", "Bontron S-36" (above,
Orient Chemical Co., Ltd.), "Aizen Spyron Black T
RH "(manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dye, metal complex of alkyl derivative of salicylic acid, for example," Bontron E-81 "," Bontron E-82 ",
Examples thereof include “Bontron E-84” and “Bontron E-85” (all manufactured by Orient Chemical Co., Ltd.); quaternary ammonium salts such as “COPY CHARGE NX VP434” (manufactured by Hoechst) and nitroimidazole derivatives. Preferably, Bontron S-34 can be used. The above charge control agent is used in an amount of 0.1 to 8.0% by weight, preferably 0.2 to 5.0% by weight, based on the binder resin.

Further, it is preferable to use wax such as polyolefin as the offset preventing agent.
It is preferable to use 1 to 5 parts by weight with respect to 00 parts by weight.
Here, examples of the polyolefin include polyethylene, polypropylene and the like, and those having a relatively low molecular weight, particularly those having a molecular weight of 3,000 to 1,500 by a vapor permeation method.
0 is preferable. The softening point by the ring and ball method is 70
˜150 ° C., especially 120 to 150 ° C. is preferable.
In conventional toners, it was difficult to blend these waxes due to poor compatibility, but in the present invention, they can be easily blended, and by blending these waxes, low temperature fixability is further improved. It will be excellent.

Further, when the toner is manufactured, a property improving agent such as a fluidity improving agent such as hydrophobic silica may be added, but when the binder resin of the present invention is used, these properties improving agents may be added. It is not necessary to add the property improving agent, and even when it is added, the addition amount may be small.

After uniformly dispersing the binder resin of the present invention, a colorant and, in some cases, a property improving agent, melt kneading, cooling, pulverizing and classifying by a known method to obtain an average particle size of 5 to 15 μm. Toner can be obtained. Further, the toner is made into a dry two-component developer by mixing a magnetic powder, that is, an iron oxide-based carrier, a spherical iron oxide-based carrier or a ferrite-based carrier as it is or with a resin coated. You can

In order to generate the magnetic toner, magnetic particles may be added to the binder resin. As the magnetic particles, for example, ferrite, magnetite and other iron, cobalt, nickel and other ferromagnets or alloys showing ferromagnetism, compounds containing these elements, or containing no ferromagnetism elements, an appropriate heat treatment is applied. Examples thereof include alloys that exhibit ferromagnetism, such as manganese-copper-aluminum, manganese-copper-tin, and other types of alloys called Heusler alloys containing manganese and copper, or chromium dioxide. A compound containing a ferromagnetic element is preferably used, and magnetite is particularly preferably used. These magnetic materials are uniformly dispersed in the binder resin in the form of fine powder having an average particle size of 0.1 to 1 μm. The content thereof is 20 to 70 parts by weight, preferably 30 to 70 parts by weight, based on 100 parts by weight of the binder resin.

[0043]

EXAMPLES The present invention will be described in more detail with reference to Examples, Comparative Examples and Test Examples, but the present invention is not limited to these Examples.

The acid value, glass transition temperature and molecular weight of the obtained binder resin were measured by the following methods. [Acid Value] The acid value was measured according to the method described in JIS K0070. [Glass Transition Temperature (Tg)] Using a differential scanning calorimeter (manufactured by Seiko Denshi Kogyo Co., Ltd.), the temperature was raised to 100 ° C., allowed to stand for 3 minutes at that temperature, and then cooled to room temperature at a temperature lowering rate of 10 ° C./min. When the sample was measured at a heating rate of 10 ° C / min., The intersection of the extension line of the baseline below the glass transition temperature and the tangent line showing the maximum slope from the rising portion of the peak to the peak apex The temperature was taken as the glass transition temperature (Tg). [Measurement of molecular weight by GPC] The column was stabilized in a constant temperature bath at 40 ° C., and chloroform as an eluent was caused to flow at a flow rate of 1 ml / min to prepare a sample chloroform solution adjusted to a sample concentration of 0.05 to 0.5% by weight. Inject 100 μl and measure. The molecular weight of the sample was calculated from the molecular weight distribution determined from the retention time based on the calibration curve prepared in advance. The calibration curve at this time was prepared using several kinds of monodisperse polyethylene as standard samples. Analytical column: GMHLX + G3000HXL (manufactured by Tosoh Corporation)

Example 1 As a vinyl resin monomer, styrene 410 g, 2-
90 g of ethylhexyl acrylate and 20 g of azobisisobutyronitrile as a polymerization initiator are placed in a dropping funnel. 780 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 24 g of fumaric acid, 76 g of isododecenyl succinic anhydride, 250 g of terephthalic acid and 2 g of dibutyltin oxide, 4 liters of glass 5 liter Put it in a flask, attach a thermometer, a stainless stir bar, a downflow condenser and a nitrogen introduction tube, stir at a temperature of 135 ° C in a nitrogen atmosphere in a mantle heater, and use a vinyl resin unit from the dropping funnel. The polymer and the polymerization initiator were added dropwise over 1 hour. 135
The mixture was aged for 2 hours while being kept at ℃, and heated to 230 ℃ to react. The degree of polymerization was traced from the softening point according to ASTM E28-67, and the reaction was terminated when the softening point reached 120 ° C.

The glass transition temperature (Tg) of the obtained resin was 60 ° C. with one peak. The vinyl resin had an average dispersed particle diameter of 0.5 μm, which was in a good dispersed state. The area ratio of the dispersed phase having a diameter of 2 μm or less in the resin cross section was 97%. Here, the dispersed particle diameter is 0.2 m
m of resin was cut with a microtome to a thickness of 150 nm, and the resulting flakes were cut with a transmission scanning electron microscope (JEOL
(JEM-2000, manufactured by JEOL Ltd.) was used for the measurement. The area ratio of the dispersed phase was determined by image analysis of photographs. Acid value is 8.0 KOHmg
/ G. Moreover, the polymerization of the vinyl resin was completed before the reaction temperature was raised to 230 ° C., but the vinyl resin at that time had a number average molecular weight of 10,0 according to GPC measurement.
It was 00. The obtained resin is referred to as Binder Resin A.

Example 2 As a vinyl resin monomer, styrene 400 g, 2-
77 g of ethylhexyl acrylate, 15 g of a dimer of α-methylstyrene as a chain transfer agent, and 25 g of dicumyl peroxide as a polymerization initiator are placed in a dropping funnel. Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 800 g, fumaric acid 15 g, 1,2,4-benzenetricarboxylic acid 60
g, 250 g of isophthalic acid and 2 g of dibutyltin oxide
Was placed in a glass 5-liter four-necked flask, and a thermometer, a stainless stir bar, a flow-down condenser and a nitrogen introduction tube were attached. The following operations were performed under the same polymerization conditions as in Example 1. The obtained resin was evaluated in the same manner as in Example 1. As a result, the glass transition temperature of the resin was 63 ° C with one peak, and the average dispersed particle diameter of the vinyl resin was 0.7μ.
m, indicating a good dispersion state. The area ratio of the dispersed phase having a diameter of 2 μm or less in the resin cross section was 95%. The acid value was 4.5 KOHmg / g. Further, the number average molecular weight of the vinyl-based resin before the temperature rise at 230 ° C. at the completion of the polymerization reaction was 5,000. The obtained resin is referred to as Binder Resin B.

Comparative Example 1 350 g of styrene, 150 g of butyl methacrylate, and 25 g of dicumyl peroxide as a polymerization initiator were placed in a dropping funnel as the vinyl resin monomer. Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 780 g, isophthalic acid 240
g, 1,2,4-benzenetricarboxylic acid (76 g) and dibutyltin oxide (2 g) were placed in a glass 5-liter four-necked flask, and a thermometer, a stainless stir bar, a downflow condenser and a nitrogen inlet tube were attached. The following operations were performed under the same polymerization conditions as in Example 1.

The resin thus obtained was evaluated in the same manner as in Example 1. As a result, the glass transition temperature of the resin was 6 with one peak.
At 2 ° C., the average dispersed particle diameter of the vinyl resin was 5.0 μm, which showed a bad dispersion state. The area ratio of the dispersed phase having a diameter of 2 μm or less in the resin cross section was 70%. The acid value was 9.3 KOHmg / g. In addition, the reaction temperature is 23
The number average molecular weight of the vinyl resin before heating at 0 ° C. is 17,000.
It was 0. The obtained resin is referred to as a binder resin C.

Comparative Example 2 As a vinyl-based resin monomer, xylene 550 g was placed in a 2-liter glass 4-neck flask equipped with a thermometer, a stainless stir bar, a flow-down condenser and a nitrogen inlet tube.
Was charged, the atmosphere was replaced with nitrogen, and the temperature was raised to 135 ° C. Styrene 70
0 g, 300 g of butyl methacrylate and 50 g of dicumyl peroxide as a polymerization initiator were placed in a dropping funnel, added dropwise over 1 hour, and aged at 135 ° C. for 2 hours. Then, the temperature was raised to 200 ° C., xylene was distilled off under reduced pressure, the mixture was extracted into a vat, cooled, and then pulverized. AS
The softening point according to TM E28-67 was 110 ° C, and the glass transition temperature was 66 ° C. The number average molecular weight of the resin measured by GPC was 17,000. The obtained resin is referred to as Binder Resin D.

500 g of the above resin D, 800 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 15 g of fumaric acid, 1,2,4
-60 g of benzene tricarboxylic acid, 250 of isophthalic acid
g and 2 g of dibutyltin oxide were placed in a glass 5 liter 4-necked flask, and a thermometer, a stainless steel stirring rod,
A downflow condenser and a nitrogen introduction tube were attached, and the reaction was carried out in a mantle heater at 230 ° C. under a nitrogen atmosphere.
The degree of polymerization was traced from the softening point according to ASTM E28-67, and the reaction was terminated when the softening point reached 120 ° C.

The resin thus obtained was evaluated in the same manner as in Example 1. As a result, the glass transition temperature of the resin is 63 ℃, 66 ℃
And two peaks were shown. The average dispersed particle diameter of the vinyl resin was 10.0 μm, and a large sea-island structure was observed.
The area ratio of the dispersed phase having a diameter of 2 μm or less in the resin cross section was 10%. The acid value was 9.7 KOHmg / g. The obtained resin is referred to as Binder Resin E.

Comparative Example 3 Polyoxypropylene (2.2) used in Example 1
2,2-bis (4-hydroxyphenyl) propane 78
0 g, fumaric acid 24 g, isododecenyl succinic anhydride 7
6 g, terephthalic acid 250 g and dibutyltin oxide 2
g was homopolymerized. The degree of polymerization is ASTM E28-6.
Followed from the softening point according to 7, the softening point is 110 ℃
The reaction was terminated when the temperature reached.

The resin thus obtained was evaluated in the same manner as in Example 1. As a result, the glass transition temperature of the resin was 63 ° C. The acid value was 15.0 KOHmg / g. 780 g of the above resin was placed in a 2 liter glass four-necked flask equipped with a thermometer, a stainless stir bar, a downflow condenser and a nitrogen introducing tube, 250 g of xylene was added to dissolve the resin, and the temperature was raised to 135 ° C. did. Next, styrene 4 was used as a monomer of the vinyl resin used in Example 1.
10 g, 90 g of 2-ethylhexyl acrylate and 20 g of azobisisobutyronitrile as a polymerization initiator were placed in a dropping funnel and added dropwise over 1 hour, followed by aging for 2 hours. After that, the temperature was raised to 200 ° C., xylene was distilled off under reduced pressure, and when the softening point reached 120 ° C., it was taken out into a vat, cooled, and ground.

The glass transition temperature of the obtained resin showed two peaks at 63 ° C and 65 ° C. The average dispersed particle diameter of the vinyl resin was 7.0 μm, and a large sea-island structure was observed. The area ratio of the dispersed phase having a diameter of 2 μm or less in the resin cross section was 25%. The acid value is 9.0 KOHmg /
It was g. The obtained resin is referred to as a binder resin F.

Comparative Example 4 Polyoxypropylene (2.2) used in Comparative Example 1
2,2-bis (4-hydroxyphenyl) propane 78
0 g, 240 g of isophthalic acid, 76 g of 1,2,4-benzenetricarboxylic acid and 2 g of dibutyltin oxide were placed in a glass 5-liter 4-necked flask, and a thermometer, a stainless steel stirring rod, a downflow condenser and a nitrogen introducing pipe were added. Mounted and polymerized alone.

The resin thus obtained was evaluated in the same manner as in Example 1. As a result, the softening point of the resin was 130 ° C and the glass transition temperature was 60.3 ° C. The acid value is 15.0KOH
It was mg / g. The obtained resin is referred to as a binder resin G.

Comparative Example 5 Styrene 820 g, 2-
180 g of ethylhexyl acrylate and 40 g of azobisisobutyronitrile as a polymerization initiator are placed in a dropping funnel. 390 g of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 12 g of fumaric acid, 55 g of isododecenyl succinic anhydride, 110 g of terephthalic acid and 1 g of dibutyltin oxide, 4 liters of glass 5 liter Put in a flask, and attach a thermometer, a stainless stir bar, a downflow condenser and a nitrogen inlet tube. The following operations were performed under the same polymerization conditions as in Example 1.

The resin thus obtained was evaluated in the same manner as in Example 1. As a result, when the glass transition temperature of the resin was determined by DSC, there was only one peak, it was 60 ° C., the average dispersed particle diameter of the polyester resin was 8.0 μm, and a large sea-island structure was observed. Also, the diameter of the resin cross section is 2
The area ratio of the dispersed phase having a size of μm or less was 20%. The acid value was 8.0 KOHmg / g. The obtained resin is referred to as a binder resin H.

Example 3 As the vinyl resin monomer, styrene 410 g, 2-
90 g of ethylhexyl acrylate and 20 g of dicumyl peroxide as a polymerization initiator are placed in a dropping funnel. 800 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 10 g of fumaric acid, 255 g of terephthalic acid, 60 g of 1,2,4-benzenetricarboxylic acid and 2 g of dibutyltin oxide.
Was placed in a glass 5-liter four-necked flask, equipped with a thermometer, a stainless stir bar, a downflow condenser and a nitrogen introduction tube, and stirred at a temperature of 160 ° C. under a nitrogen atmosphere in a mantle heater while The vinyl resin monomer and the polymerization initiator were added dropwise from the dropping funnel over 1 hour. Aged for 2 hours while maintaining at 160 ℃, 230
The temperature was raised to ° C and the reaction was carried out. The following operations were performed under the same polymerization conditions as in Example 1.

The resin thus obtained was evaluated in the same manner as in Example 1. As a result, the glass transition temperature of the resin was 6 with one peak.
At 1 ° C., the average dispersed particle diameter of the vinyl resin was 1.5 μm, which was in a good dispersed state. Also, the diameter of the resin cross section is 2μ
The area ratio of the dispersed phase of m or less was 92%. The acid value is 8.
It was 7 KOHmg / g. Also, when the polymerization reaction is completed,
The number average molecular weight of the vinyl resin before heating at 30 ° C. is 7,50
It was 0. The obtained resin is referred to as Binder Resin I.

Comparative Example 6 As a vinyl resin monomer, 410 g of styrene, 2-
90 g of ethylhexyl acrylate and 20 g of dicumyl peroxide as a polymerization initiator are placed in a dropping funnel. 800 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 4 g of fumaric acid, 260 g of terephthalic acid, 60 g of 1,2,4-benzenetricarboxylic acid and 2 g of dibutyltin oxide,
It was placed in a glass 5-liter 4-neck flask, equipped with a thermometer, a stainless stir bar, a downflow condenser and a nitrogen inlet tube, and placed in a mantle heater under a nitrogen atmosphere under a nitrogen atmosphere.
While stirring at a temperature of 0 ° C., the vinyl resin monomer and the polymerization initiator were added dropwise from the above dropping funnel over 1 hour.
The mixture was aged for 2 hours while maintaining the temperature at 160 ° C, and the temperature was raised to 230 ° C for reaction. The following operations were performed under the same polymerization conditions as in Example 1.

The obtained resin was evaluated in the same manner as in Example 1. As a result, the glass transition temperature of the resin was 6 with one peak.
At 2 ° C., the average dispersed particle diameter of the vinyl resin was 3.0 μm. The area ratio of the dispersed phase having a diameter of 2 μm or less in the resin cross section was 80%. The acid value was 9.2 KOHmg / g. Further, the number average molecular weight of the vinyl-based resin before the temperature rise at 230 ° C. at the completion of the polymerization reaction was 8,000. The resin thus obtained is referred to as Binder Resin J.

Test Example Materials having the compositions shown in Table 1 were premixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, cooled, and then subjected to normal crushing,
An untreated toner having an average particle size of 11 μm was manufactured through a classification process.

[0065]

[Table 1]

The resulting untreated toners 1 to 4 and 10 were
For each 100 parts by weight of hydrophobic silica "H-20
00 "(manufactured by Wacker Chemicals Co., Ltd.) 0.1 parts by weight was mixed and adhered using a Henschel mixer to obtain toners 1 to 5. Similarly, silica was adhered to untreated toners 5 to 9 and 11 to obtain comparative toners 1 to 6, respectively. 39 parts by weight of each of the above toners and spherical ferrite powder coated with styrene / methyl methacrylate resin (average particle size 100
μm) 1261 parts by weight to prepare a developer, and a commercially available electrophotographic copying machine (photoreceptors are toners 1, 2, 4, 5,
Amorphous selenium was used for comparative toners 1, 2, 3, 4, 5 and 6, and an organic photoconductor was used for toner 3, and the rotation speed of the fixing roller was set to 255 mm / sec.
The heat roller temperature in the fixing device was made variable, and an image was printed using an oil removing device), and the printing durability and fixing property were evaluated by the following methods.

(1) The charge amount was measured by a blow-off type charge amount measuring device described below, that is, a specific charge measuring device equipped with a Faraday cage, a condenser and an electrometer. The measuring method is as follows. First, the developer prepared above is mixed with W (g) (0.15 to 0.20 g) at 50
Place in a brass measuring cell equipped with a 0 mesh stainless steel mesh (the size can be changed as appropriate to prevent carrier particles from passing). Next, after suctioning for 5 seconds from the suction port, the air pressure is blown for 5 seconds at an air pressure of 0.6 kg / cm ² to remove only the toner from the cell.

At this time, the voltage of the electrometer 2 seconds after the start of the blow is set to V (volt). If the electric capacity of the condenser is C (μF), the specific charge of this toner is Q /
m is calculated by the following equation.

Q / m (μC / g) = C × V / m

Here, m is the weight of the toner contained in the developer in W (g), where T (g) is the weight of the toner in the developer and D (g) is the weight of the developer. In that case, the toner density of the sample is expressed as T / D × 100 (%), and m is calculated by the following equation.

M (g) = W × (T / D)

The developer was used in the copying machine, and continuous copies of 100,000 sheets were made under normal environment (23 ° C., 50% R).
H), high temperature, high humidity (35 ° C, 85% RH)
The change in charge amount and the occurrence of background stain during the printing durability test were evaluated. The results are shown in Table 2.

[0073]

[Table 2]

(2) The fixing property of the toner was evaluated by the minimum fixing temperature. Here, the minimum fixing temperature is a reflection densitometer of Macbeth Inc. before and after rubbing 5 times on the image fixed through a fixing machine, placing a load of 500 g on a sand eraser having a bottom surface of 15 mm x 7.5 mm, and rubbing. The optical reflection density is measured according to the following, and it means the temperature of the fixing roller when the fixing rate exceeds 70% according to the following definition.

Fixing rate (%) = [(image density after rubbing) /
(Image density before rubbing)] x 100

The fixing roller temperature was controlled between 100 and 240 ° C. to evaluate the fixing property. The results are shown in Table 3.

(3) Regarding the offset resistance,
It was evaluated by measuring the low temperature offset extinction temperature and the high temperature offset generation temperature. That is, the temperature of the surface of the heat roller was raised by 5 ° C. in the range of 70 to 240 ° C. to perform a copy test, and the adhesion of the toner on the surface of the heat roller was visually evaluated at each temperature.

[0078]

[Table 3]

From the results shown in Table 2, the toners 1 to 5 were compared with the comparative toners 1 to 6 under normal environment (23 ° C., 50% R).
H) and the change in charge amount under high temperature and high humidity (35 ° C., 80% RH) are small and the image quality is good, so that it can be used under severe environmental conditions. Further, from the results in Table 3, the toners 1 to 5 had lower minimum fixing temperature and low temperature offset extinction temperature than the comparative toners 2 to 4, and had good image stability and thermal efficiency.

[0080]

The toner of the present invention is stable in the amount of charge and the image quality regardless of the environment, and in the fixing method of the heat roller, the fixing can be performed at a low temperature without using the offset preventing liquid. Possible toner.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tetsuhiro Semura 5-45, Fukiage, Wakayama City, Wakayama Prefecture (72) Inventor Katsutoshi Aoki 1130 Nishihama, Wakayama City, Wakayama Prefecture Inventor Kuniyasu Kawabe Komatsubara, Wakayama City, Wakayama Prefecture 6-1-55

Claims (9)

[Claims] 1. An electrophotographic toner containing at least a binder resin and a colorant, wherein the binder resin comprises a polycondensation resin that forms a continuous phase and an addition polymerization resin that forms a dispersed phase. The dispersed phase having a diameter of 2 μm or less in
An electrophotographic toner comprising 90% or more of the entire cross-sectional area of the dispersed phase. 2. The toner for electrophotography according to claim 1, wherein the weight ratio of the polycondensation resin to the addition polymerization resin is 50/50 to 95/5. 3. The electrophotography according to claim 1, wherein the polycondensation resin is one or more selected from the group consisting of polyester, polyester-polyamide and polyamide, and the addition polymerization resin is a vinyl resin. For toner. 4. The number average molecular weight of the vinyl resin is 5,000.
The toner for electrophotography according to claim 3, which is about 20,000. 5. The toner for electrophotography according to claim 1, wherein the binder resin has an acid value of less than 20 KOHmg / g. 6. The binder resin is added to a mixture of raw material monomers of polyester, polyester-polyamide or polyamide under a temperature condition suitable for the addition polymerization reaction, and the mixture of raw material monomers of vinyl resin is added dropwise to the addition polymerization reaction. In parallel, a step of partially conducting the polycondensation reaction, a step of maintaining the temperature of the obtained mixture under the above conditions to complete only the addition polymerization reaction, and then raising the reaction temperature to polymerize the polycondensation reaction. The toner for electrophotography according to any one of claims 1 to 5, which is obtained by a method comprising a step of increasing the degree. 7. The raw material monomer for the vinyl resin is one or more selected from the group consisting of styrene, acrylic acid, butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid and butyl methacrylate.
The described electrophotographic toner. 8. A raw material monomer for polyester, polyester-polyamide or polyamide is one or more acid components selected from the group consisting of terephthalic acid, trimellitic acid, alkenylsuccinic acid, fumaric acid and maleic acid, and bisphenol. The toner for electrophotography according to claim 6 or 7, which comprises one or more alcohol or amine components selected from the group consisting of an alkylene oxide adduct of A, hexamethylenediamine and ε-caprolactam. 9. The electrophotographic toner according to claim 1, further comprising a wax.