JP3041132B2 - Additive for developer and developer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a developer additive and a developer composition for developing an electrostatic image in electrostatic printing and the like. More specifically, the present invention relates to a developer additive and a developer composition having improved toner fixing performance (low-temperature fixability and offset resistance) and pulverizability by being used in an electrophotographic system.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, as described in U.S. Pat. Nos. 2,297,691 and 2,357,809, a photoconductive insulating layer is uniformly charged, and then the layer is exposed. An electric latent image is formed by dissipating the charge of the exposed portion, and the latent image is visualized by adhering a fine powder having a colored charge called toner to the latent image (development step). ,
After the obtained visible image is transferred to a transfer material such as transfer paper (transfer step), a step of fixing permanently by heating, pressure or other appropriate fixing method (fixing step) is included.
As described above, the toner must have functions required not only in the developing step but also in each of the transferring step and the fixing step.

[0003] In recent years, it has been strongly desired that a copying machine, a printer, and the like using an electrophotographic system provide printed matter with higher speed and higher image quality. Various methods and apparatuses have been developed for fixing a toner image in response to this demand. The most common method at present is a so-called hot roller fixing method in which heat and pressure are applied simultaneously. In a high-speed copying machine or the like having this fixing method, continuous fixing is performed many times, so the heat of the heat roller is deprived to a considerable amount by the image support, and heat supply cannot be performed in time, resulting in a decrease in the temperature of the heat roller. And fixing failure is likely to occur.
Therefore, there is a demand for the development of a toner capable of fixing at a lower temperature in a high-speed copying machine or the like.

[0004] Polyester resin is inherently good in fixing property and can be sufficiently fixed even in a non-contact fixing method as described in, for example, US Pat. No. 3,590,000. The phenomenon was liable to occur and the use was difficult. The offset phenomenon means that the toner contacts the surface of the heat roller in a molten state when fixing the heat roller, and a part of the molten toner is transferred and adhered to the surface of the heat roller, and this is the next image support that is sent. It is a phenomenon that retransfers to the body and stains the image.

Therefore, in a high-speed copying machine or the like having a heat roller fixing method, there is a strong demand for development of A: toner having excellent anti-offset properties, and B: toner having excellent low-temperature fixing properties. Conventionally, as a method for improving the offset resistance, use of a crosslinked resin has been proposed (Japanese Patent Publication No. 51-23354, Japanese Patent Application Laid-Open No. Sho 59-908).
No. 66, Japanese Patent Publication No. 59-11902, etc.). Further, as a method for improving the low-temperature fixability while satisfying the offset resistance, it has been proposed to introduce a soft segment into a side chain (JP-A-57-109825, JP-A-59-7960). etc). Further, a method of adding a low-molecular-weight polyolefin wax to impart releasability to a toner from a fixing roller is also performed (Japanese Patent Application Laid-Open Nos. 49-65232 and 50-28840). Furthermore, it is proposed to improve the thermal responsiveness of the fixing heat roller by using an aromatic bisamide with a molecular weight of 500 to 1500 as a fixing property improving aid, so that both the fixing property to paper and the release property from the fixing roller are compatible. (Japanese Unexamined Patent Publication No.
No. 986).

[0006]

However, in the above-mentioned technology, the fixing temperature rises simply by using a cross-linked resin, and unfixed portions are generated under normal fixing conditions, and problems such as stains on an image occur. Occur. In addition, in the above-mentioned technology, although the fixing is certainly improved,
Since the toughness of the resin increases, the pulverizability of the resin, which is related to the productivity of the toner, deteriorates, and the productivity of the toner deteriorates. Further, in the above-mentioned technique, although it is effective in preventing offset, a large amount of addition causes a decrease in charging characteristics due to a decrease in fluidity of the toner. In addition, there is no effect if the addition amount is small. Further, in the above-mentioned technology, although the effect of improving the fixing property is effective, the aromatic bisamide may reduce the degree of polymerization of the binder resin having a functional group such as an ester group or an amide group, so that the developer composition may be reduced. Lot fluctuation occurs in the melt viscosity, and it is difficult to produce a stable developer composition.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a developer additive having improved toner fixing performance (low-temperature fixability, offset resistance) and pulverizability. And a developer composition.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, completed the present invention. That is, the present invention provides a developer additive comprising the compound represented by the general formula (1).

[0009]

Embedded image

Wherein A ₁ and A ₂ are an alkyl group, an alkenyl group or an arylalkyl group, n is 0 or 1, and X is

[0011]

Embedded image

One of the following: Where R ₁ , R ₂
Represents H or an alkyl group having 4 or less carbon atoms. Further, the present invention also provides a developer composition comprising an additive comprising the compound represented by the general formula (1), a binder resin, and a colorant.

In the compound represented by the general formula (1) according to the present invention, the carbon numbers of A ₁ and A ₂ can be arbitrarily selected. However, it preferably has 6 to 18 carbon atoms. If the number of carbon atoms of A ₁ and A ₂ is less than 6, the effect of improving the fixing property is small.
If the ratio exceeds the above range, the compatibility with the resin becomes poor, and the fluidity, chargeability, blocking resistance and the like of the toner are undesirably impaired. As A ₁ and A ₂ , specifically, n-hexyl group, n-octyl group, n-dodecyl group, linear alkyl group such as n-octadecyl group, 2-hexyldecyl group, methyl branched octadecyl group and the like Branched alkyl group or benzyl group, 2
An arylalkyl group such as -phenylethyl group. The compound represented by the general formula (1) according to the present invention is:
General formula (3)

[0014]

Embedded image

(Wherein X and n have the same meanings as described above) with respect to an aromatic glycol represented by the formula:
Or the like, by reacting an alkyl halide and / or an arylalkyl halide in the presence of an alkali catalyst such as Specific examples of the compound represented by the general formula (1) according to the present invention are as follows.

[0016]

Embedded image

[0017]

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The compound represented by the general formula (1) according to the present invention is preferably added at a ratio of 0.1 to 10.0% by weight based on the binder resin in order to exhibit the intended performance. . More preferably, it is 0.5 to 8.0% by weight, more preferably 1.0 to 5.0% by weight. When the amount of the compound represented by the general formula (1) is less than 0.1% by weight based on the binder resin, the effect of improving the fixability is weak. On the other hand, 10.0% by weight
When the ratio exceeds the above range, the fluidity, chargeability, blocking resistance and the like of the toner tend to be impaired, and the offset resistance tends to deteriorate.

The method of adding the compound represented by the general formula (1) according to the present invention to the developer composition for electrophotography may be carried out at the time of or after the production of the binder resin.
When kneading the binder resin, the colorant, and the additives used as necessary, they may be melt-mixed.

The compound represented by the general formula (1) according to the present invention is a thermally stable compound which does not emit smoke or color even when exposed to a high temperature during the production of a binder resin. In addition, it is not only a compound that is chemically stable to the esterification catalyst and radical polymerization initiator used in the production of the binder resin, but also to the functional groups such as the ester group and the amide group of the binder resin. Since they have no effect, they have an excellent feature that they do not contribute to lowering of the polymerization degree of the resin and generation of low molecular weight components.

The compound represented by the general formula (1) according to the present invention has an alkyl group or the like and an aromatic ring having a large cohesive force in a molecule, and as a result, the releasability from a heat roller fixing machine. Thus, it is considered that the toner has a performance of giving a cohesive force of the toner. Further, since the compound has an effect of lowering the melt viscosity of the binder resin, it is considered that the compound has an effect of lowering the melt viscosity of the toner when the toner passes through a heat roller fixing machine and assisting transfer to a transfer paper or the like.

Examples of the binder resin used in the present invention include polyester, polyester polyamide or polyamide resin obtained by a polycondensation reaction, and vinyl resin obtained by an addition polymerization reaction. Polyester is obtained by using a polyhydric alcohol, a polycarboxylic acid or a polycarboxylic acid ester, a polycarboxylic anhydride, or the like as a raw material monomer, and as a dihydric alcohol component of the polyhydric alcohol, The bisphenol A alkylene oxide adduct represented by the following general formula (2) is effective.

[0023]

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Wherein R ₃ is an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the average of the sum is 2
~ 16. Examples of the bisphenol A alkylene oxide adduct 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, polyoxyethylene (2.5) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6.0)-
2,2-bis (4-hydroxyphenyl) propane and the like can be mentioned.

As the dihydric alcohol component, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentane Diol, 1,6
Aliphatic diols such as -hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, and other dihydric alcohols can also be used.

When the bisphenol A alkylene oxide adduct represented by the general formula (2) is used as a constituent monomer, a polyester resin having a relatively high glass transition point due to the nature of the bisphenol A skeleton is obtained, and the blocking resistance is improved. It will be good. In addition, the bisphenol A skeleton
Since the molecular weight is large, it contributes to increase the molecular weight of the polymer, and is effective in offset resistance.

Among the monomers constituting the polyester resin in the present invention, examples of the divalent carboxylic acid component include 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, and the following general formula (4) or (5)

[0028]

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(Wherein R ₄ and R ₅ are saturated or unsaturated hydrocarbon groups having 4 to 20 carbon atoms), for example, n-dodecyl succinic acid, n- Dodecenyl succinic acid, n-octyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octenyl succinic acid, and anhydrides or lower alkyl esters of these divalent carboxylic acids, other divalent carboxylic acids Can be mentioned.

In the case of an electrophotographic developer composition, particularly when offset resistance is required, it is effective to partially crosslink in the molecule of the binder resin. Crosslinking is achieved by using trifunctional or higher polyfunctional compounds.
Examples of the trivalent or higher polyols as a crosslinking agent include sorbitol, 1,2,3,6-hexane tetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
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 used.

Examples of the trivalent or higher polycarboxylic acid as a crosslinking agent include trimellitic acid, 2,5,5
7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene Carboxylpropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,2
7,8-octanetetracarboxylic acid, pyromellitic acid,
Empole trimer acids, anhydrides or lower alkyl esters of these acids, and the like can be used. A particularly preferred trivalent or higher polycarboxylic acid is trimellitic anhydride.

The polyfunctional compound having a valence of 3 or more is used in an amount of from 0.5 mol% to less than 15.0 mol%, preferably from 1.5 mol% to less than 12.0 mol%, more preferably from 2.5 mol% to less than 1 mol% of the total monomer amount.
Less than 10.0 mol% can be used. Tri- or higher valent polyols and tri- or higher valent polycarboxylic acids can be used alone or in combination. However, if the total amount exceeds 15.0 mol%, the production stability of the polyester resin deteriorates, which is not preferable. When a trifunctional or higher polyfunctional compound is used, the use of less than 0.5 mol% of the total amount of the monomer has little effect on the offset resistance.

The polyester resin used in the present invention can be produced by polycondensing a polycarboxylic acid component and a polyol component at a temperature of 180 to 250 ° C. in an inert gas atmosphere. At this time, in order to accelerate the reaction, a commonly used esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate and the like can be used. For the same purpose, it can be produced under reduced pressure.

As the polyester polyamide or polyamide used in the present invention, generally known polyester polyamides or polyamides can be used. Among the raw material monomers forming the amide component in the polyester polyamide or polyamide, examples of the polyamine include ethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, iminobispropylamine, phenylenediamine, xylylenediamine, triethylenetetramine and the like. And aminocarboxylic acids such as 6-aminocaproic acid and ε-caprolactam, and amino alcohols such as propanolamine.

As the vinyl resin used in the present invention, generally known resins can be used. Representative monomers used to form the vinyl resin include, for example, styrene, o-methylstyrene, m-methylstyrene,
Styrene-based monomers such as p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-chlorostyrene and vinylnaphthalene, for example, ethylene such as ethylene, propylene, butylene and isobutylene Unsaturated monoolefins, for example, vinyl chlorides such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl formate, vinyl caproate, etc., 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-octyl acrylate, isooctyl acrylate, acrylic acid Decyl, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methoxyethyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, 2-chloroethyl acrylate, 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, glycidyl methacrylate, phenyl methacrylate, methacrylic acid Ethylenic monocarboxylic acids such as dimethylaminoethyl and diethylaminoethyl methacrylate and esters thereof, for example, acrylonitrile, methacrylonitrile , Ethylenic dicarboxylic acids such as dimethyl maleate and the like, vinyl ketones such as vinyl methyl ketone, vinyl ethers such as vinyl methyl ether, for example, vinylidene There are vinylidene halides such as chloride and the like, and N-vinyl compounds such as N-vinylpyrrole and N-vinylpyrrolidone.

When a crosslinking agent is added, for example, 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, tetramethylolmethanetetraacrylate, dibromoneopentyl glycol dimethacrylate, diallyl phthalate, etc. (In combination of two or more). If these cross-linking agents are used in a large amount, it becomes difficult for the toner to be melted by heat, and the heat fixing property or the heat pressure fixing property is inferior. Further, when the amount is small, it is difficult to prevent the offset phenomenon that a part of the toner does not completely adhere to the paper but adheres to the roller surface and is transferred to the next paper in the heat roller fixing. Therefore, the amount of the crosslinking agent used is preferably 0.001 to 15% by weight (more preferably 0.1 to 10% by weight) based on the polymerizable monomer.

The polymerization initiator used for producing the vinyl resin includes 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, , 1'-Asobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-
2,4-dimethylvaleronitrile, other azo or diazo polymerization initiators, or benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,
Peroxide-based polymerization initiators such as 4-dichlorobenzoyl peroxide, lauroyl peroxide and dicumyl peroxide are exemplified. For the purpose of adjusting the molecular weight and molecular weight distribution of the polymer, or for adjusting the reaction time, two or more polymerization initiators can be used in combination. The amount of the polymerization initiator to be used is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer.

It is preferable that the binder resin used in the present invention has a softening point of 95.0 ° C. or more and 160.0 ° C. or less by a Koka type flow tester. If the softening point is less than 95.0 ° C, offset resistance, blocking resistance was impaired, and 160.
If the temperature exceeds 0 ° C., the low-temperature fixability is impaired. Softening point of the binder resin in the present invention by the Koka type flow tester,
It is defined as follows. That is, using a Koka type flow tester (CFT-500) (manufactured by Shimadzu Corporation)
Die pore diameter 1mm, pressurization 20kg / cm ² , heating rate 6 ℃ / m
The softening point is defined as the temperature corresponding to half the height from the outflow start point to the outflow end point when a 1 cm ³ sample is melted out under the condition of in.

As another physical property of the binder resin used in the present invention, the glass transition temperature measured by DSC (differential scanning calorimeter) is preferably 50.0 ° C. or more and 80.0 ° C. or less. 50.0
When the temperature is lower than 8 ° C., the blocking resistance is impaired, and when it is higher than 80.0 ° C., the low-temperature fixability is impaired.

Examples of the colorant that can be used in the present invention include various carbons produced by a thermal black method, an acetylene black method, a channel black method, a furnace black method, a lamp black method and the like in the case of a black toner. For black and color toners, copper phthalocyanine, monoazo pigments (CIPigme
nt Red 5, CIPigment Orange 36, CIPigment Red 2
2), disazo pigment (CIPigment Yellow 83), anthraquinone pigment (CIPigment Blue 60), disazo pigment (Solvent Red 19), rhodamine dye (Solvent Red 4)
9) and the like, and these are represented by the binder resin and the general formula (1)
In the compound represented by, and in some cases with a positive or negative charge control agent after sufficiently uniform dispersion by a ball mill or the like,
Melt and knead in a kneader, pulverize after cooling, average particle size 5
Used as 15 μm colored powder or toner. As a dry two-component developer, the toner is an amorphous carrier,
An appropriate amount is blended with a magnetic powder such as a ferrite-based coated carrier and a spherical coated carrier, and used as a developer.

The positive charge control agent that can be used in the present invention is not particularly limited, from low molecular weight compounds to high molecular weight compounds (including polymers). For example, nigrosine-based dyes “nigrosin base EX”, “oil black BS”, “oil black SO” (above,
Orient Chemical Co., Ltd.), triphenylmethane dyes,
Examples include a quaternary ammonium compound and a vinyl polymer having an amino group. Examples of the negative charge control agent that can be used in the present invention include metal complex salts of monoazo dyes, nitrohumic acid and salts thereof, substances having a nitro group and a halogen element, sulfonated copper phthalocyanine,
And maleic anhydride copolymers.

Further, a magnetic fine powder can be contained in the toner for the purpose of improving a developing mechanism or an image. Examples of the magnetic powder include alloys and compounds containing ferromagnetic elements such as ferrite and magnetite. The magnetic powder is contained in the binder resin in the form of fine powder having an average particle size of 0.05 to 1 μm. Up to 70% by weight can be dispersed and used.

Known properties improvers contained in the toner according to the present invention include an anti-offset agent, a fluidizing agent, and a heat property improver (for example, a chromium complex such as 3,5-di-tert-butylsalicylate). There are metal complexes and metal oxides such as zinc oxide), but the use of these as appropriate does not hinder the present invention.

[0044]

Hereinafter, embodiments of the present invention will be described.
The present invention is not limited to these examples. The parts in the examples are on a weight basis.

Production Example 1 (Binder Resin-1) 5.0 mol of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 5.0 mol of ethylene glycol, 8.0 mol of terephthalic acid, 1,2,4 -Benzenetricarboxylic anhydride (trimellitic anhydride) 1.0
Mol and 5.0 g of dibutyltin oxide
The flask was placed in a two-necked flask, equipped with a thermometer, a stainless steel stirrer, a falling condenser, and a nitrogen inlet tube, and heated at 220 ° C for 3 hours at 190 ° C in a nitrogen stream in a mantle heater.
For 3 hours, 240 ° C for 3 hours, and 60mmHg at the same temperature
The reaction was completed under reduced pressure for 1 hour to complete the reaction. The obtained resin was a pale yellow solid, had a softening point of 128 ° C by a flow tester, and a glass transition temperature of 67 ° C by DSC. The obtained resin is referred to as binder resin-1.

Production Examples 2 to 4 (Binder Resins 2 to 4) Binder resins 2 to 4 were produced by performing the same operations as in Production Example 1 with the raw material compositions shown in Table 1. Table 1 shows the softening point of the obtained resin by a flow tester and the glass transition temperature by DSC.

[0047]

[Table 1]

Production Example 5 (Binder Resin-5) 550 g of xylene was charged into a 2 liter glass four-necked flask equipped with a thermometer, a stainless steel stirring rod, a falling condenser, a dropping funnel and a nitrogen inlet tube. After purging with nitrogen, the temperature was raised to 135 ° C. 700 g of styrene, 300 g of butyl methacrylate and 50 g of dicumyl peroxide were put into a dropping funnel, dropped over 4 hours, and aged at 135 ° C. for 5 hours. Thereafter, the temperature was raised to 200 ° C., xylene was distilled off under reduced pressure, extracted into a vat, cooled and pulverized. The softening point by a flow tester was 120 ° C., and the glass transition temperature by DSC was 66 ° C. The obtained resin is referred to as a binder resin-5.

Production Example 6 (Binder Resin-6) 700 g of styrene and 300 g of butyl methacrylate as monomers of a vinyl resin and 50 g of dicumyl peroxide as a polymerization initiator are put into a dropping funnel. 390 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 120 g of terephthalic acid, 38 g of 1,2,5-benzenetricarboxylic acid and 1 g of dibutyltin oxide were mixed with 5 liters of glass Place the flask in a one-necked flask, attach a thermometer, a stainless steel stir bar, a falling condenser, and a nitrogen inlet tube, and stir at 135 ° C under a nitrogen stream in a mantle heater. The vinyl resin monomer and the polymerization initiator were added dropwise over 4 hours. After aging for 5 hours while maintaining the temperature at 135 ° C., the temperature was raised, and the reaction was carried out at 220 ° C. The polymerization degree is ASTM E28-67
The reaction was pursued from the softening point according to, and when the softening point reached 128 ° C., the reaction was terminated. The obtained resin is a pale yellow solid, and has a softening point of 125 ° C.
The glass transition temperature by C was 63 ° C. The obtained resin is referred to as a binder resin-6.

Example 1 A material having the following composition was mixed with a Henschel mixer, melt-mixed with a twin-screw extruder, cooled, and then subjected to a usual pulverization / classification step to prepare a toner having an average particle diameter of 10 μm. <Composition> Binder resin-1 100 parts Carbon black (# 44) (manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 7 parts Negatively chargeable charge control agent (Bontron S-34, manufactured by Orient Chemical Co., Ltd.) 2 parts Compound of the present invention 2 parts obtained 39 parts of the obtained toner and 1261 parts of resin-coated iron powder are mixed to prepare a developer, and a commercially available electrophotographic copier (photosensitive material is amorphous selenium, and the rotation speed of the fixing roller is 255 m
m / sec, the temperature of the heat roller in the fixing device is made variable,
(With the oil applicator removed).
Table 3 shows the results of evaluating the fixing property, offset property, storage stability, and toner pulverizability of the image while controlling the fixing temperature to 120 ° C. to 220 ° C.

Here, the minimum fixing temperature is 15 mm × bottom.
A 500 g load is placed on a 7.5 mm sand eraser, and the image fixed through the fixing device is rubbed five times back and forth. Before and after the rubbing, the optical reflection density is measured with a Macbeth reflection densitometer, and the density is defined as follows. This refers to the temperature of the fixing roller when the fixing rate exceeds 70%.

[0052]

(Equation 1)

The hot offset occurrence temperature was evaluated visually. Regarding storage stability, toner 50
g was evaluated by the degree of occurrence of aggregation when allowed to stand at 50 ° C. and a relative humidity of 40% for 24 hours. That is, when the amount remaining on the 42-mesh sieve was less than 3 g, the storage stability was evaluated as good (good), and when the amount was 3 g or more, it was evaluated as bad.

The pulverizability of the toner was evaluated by a simple pulverization test. That is, after melt mixing and cooling with a twin screw extruder,
Sieve coarsely ground toner with a rotoplex etc.
A toner powder that passes through 16 mesh but not through 20 mesh is obtained. 20.00 g of the classified toner powder is precisely weighed, and a coffee mill (HR-2170 type manufactured by PHLIPS) is used.
After crushing for 10 seconds, the mixture is sieved through a 32 mesh sieve, and the weight (A) g of the toner that does not pass is weighed accurately. The residual ratio is determined by the following formula. The above operations are performed three times and averaged. The average residual ratio is 0 to 15.0% [◎], 15.1 to 20.0% is [〔], 20.1 to 10%.
0% is indicated as [x].

[0055]

(Equation 2)

Examples 2 to 10 and Comparative Example 1 Using the materials having the compositions shown in Table 2, the carbon black used in Example 1, and the negatively chargeable charge control agent, the same operation as in Example 1 was carried out to obtain toner and A developer was prepared, and the physical properties were similarly evaluated. Table 3 shows the results.

[0057]

[Table 2]

[0058]

[Table 3]

As apparent from Table 3, Examples 1 to 10
The developer composition of the present invention obtained in (1) had a low minimum fixing temperature, good storage stability, and good pulverizability of the toner. However, since the compound of the present invention was not added to the developer composition obtained in Comparative Example 1, the pulverizability of the toner was poor and the minimum fixing temperature was high.

[0060]

Since the electrophotographic developer composition of the present invention contains a thermally and chemically stable compound represented by the general formula (1), the fixing effect of the toner is improved by the effect of the compound. (Low-temperature fixability, anti-offset properties), and the pulverizability of the toner is improved.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-6640 (JP, A) JP-A-61-3149 (JP, A) JP-A-62-160464 (JP, A) JP-A-62 200362 (JP, A) JP-A-1-241566 (JP, A) JP-A-5-61256 (JP, A) JP-A-6-501566 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (6)

(57) [Claims] 1. An additive for a developer comprising a compound represented by the general formula (1). Embedded image (Where A ₁ and A ₂ are an alkyl group, alkenyl group or arylalkyl group, n is 0 or 1, and X is Is one of Here, R ₁ and R ₂ represent H or an alkyl group having 4 or less carbon atoms. ) 2. A developer composition comprising the additive according to claim 1, a binder resin and a colorant. 3. The developer composition according to claim 2, wherein the ratio of the additive to the binder resin is 0.1 to 10.0% by weight. 4. The developer composition according to claim 2, wherein the binder resin is at least one selected from polyester, polyester polyamide and polyamide. 5. The developer composition according to claim 4, wherein the binder resin is a polyester having a diol component represented by the general formula (2) as a constituent unit monomer. Embedded image (Wherein, R ₃ is an alkylene group having 2 to 4 carbon atoms, x,
y is a positive integer, and the average value of the sum is 2 to 16. ) 6. The developer composition according to claim 2, wherein the binder resin is a vinyl resin.