JPH0764323A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To make fixation at a low fixing temp. possible, to solve the problem of offsetting property and to ensure excellent fixing strength and image characteristics by incorporating a specified bonding resin, polyethylene wax and a compatibility imparting agent. CONSTITUTION:This electrophotographic toner contains a bonding resin made of a polymer having carboxyl groups, polyethylene wax having at least one peak of the quantity of absorbed heat by DSC in the range of 85-110 deg.C and a graft polymer consisting of an ethylene-glycidyl methacrylate copolymer and a vinyl polymer as a compatibility imparting agent. The bonding resin is preferably vinyl resin having carboxyl groups, especially styrene resin, acrylic resin or styrene-acrylic copolymer resin or polyester resin having carboxyl groups at the terminals. The glass transition temp. of the bonding resin is preferably >=60 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner, and more particularly to an electrophotographic toner for a copying machine or printer which employs heat roll fixing.

[0002]

2. Description of the Related Art In recent years, with the spread of electrophotographic copying machines and printers including general households, the energy saving (power consumption) has been made mainly for the purpose of multifunctioning copying machines or printers. (Reduction of
Higher speed is desired for the purpose of popularization in a so-called gray area located on the boundary between a printing machine and a copying machine. Further, in order to simplify the fixing roll for the purpose of reducing the machine cost, it is desired to reduce the roll pressure. further,
Since the copying machine equipped with the double-sided copy function and the automatic document feeder has become widespread with the sophistication of the copying machine,
Toner for electrophotography used in copiers and printers has a low fixing temperature and excellent anti-offset properties, and to prevent stains from occurring during double-sided copying and when automatically fed by the automatic document feeder. There is a demand for an excellent fixing strength on a transfer paper.

In response to the above demands, conventionally, there have been proposed techniques for improving the molecular weight and the molecular weight distribution of the binder resin. Specifically, attempts have been made to lower the fixing temperature by lowering the molecular weight of the binder resin. However, although the melting point was lowered by lowering the molecular weight, the viscosity was also lowered at the same time, so that there was a problem that an offset phenomenon to the fixing roll occurred. Further, if the fixing temperature is lowered by increasing the number of low molecular weight parts of the binder resin, the toner itself becomes brittle, and the original document or the apparatus is contaminated during double-sided copying or when using the automatic document feeder. Was there.

In order to prevent the above offset phenomenon, a method of widening the low molecular weight region and the high molecular weight region of the molecular weight distribution of the binder resin or a method of crosslinking the polymer portion has been adopted. However, the glass transition temperature of the resin had to be lowered in order to provide sufficient fixability by these methods. However, lowering the glass transition temperature inevitably impairs the storage stability of the toner.

[0005]

Further, in order to improve the fixing property and prevent the occurrence of the offset phenomenon, a method of adding a polyethylene wax having a low melting point has been proposed. However, polyethylene waxes have poor compatibility with the binder resin, and if a large amount is added, the fixing performance is improved.
Inhibits the dispersion of additives. Therefore, a wax containing polyethylene wax may be broken during pulverization and classification of the kneaded product, and the broken toner may adhere to the photoconductor, so-called filming may occur, or the storage stability may be deteriorated. It was Further, a toner in which waxes are not well dispersed has a problem that the triboelectric charge amount changes when the development is repeated for a long time, and the image density decreases.

The present invention has been made in view of the above circumstances, and by improving the compatibility between the polyethylene wax and the binder resin, fixing can be performed at a low fixing temperature, and even in the non-offset property, it is practically used. It is an object of the present invention to provide an electrophotographic toner that does not cause any problems and has excellent fixing strength on transfer paper and image characteristics.

[0007]

DISCLOSURE OF THE INVENTION The present invention compatibilizes a binder resin composed of a polymer having a carboxyl group, and a polyethylene wax having a peak of absorbed heat by DSC in the range of 85 to 110 ° C. The above object was achieved by containing an ethylene glycidyl methacrylate copolymer and a graft polymer of a vinyl polymer as an agent.

The present invention will be described in detail below. In the present invention, a polymer having a carboxyl group is used as the binder resin. However, a vinyl resin such as a styrene resin, an acrylic resin, or a styrene-acrylic copolymer resin having a carboxyl group, or a polyester resin having a carboxyl group at its terminal is particularly preferable. Further, in order to improve the storage stability of the electrophotographic toner, it is preferable to use a resin having a glass transition temperature of 60 ° C. or higher.

The vinyl resin having a carboxyl group is obtained by polymerizing the following monomer and a carboxyl group-containing monomer by a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, a bulk polymerization method or the like. Obtainable.
Examples of the monomer include styrenes such as styrene, α-methylstyrene, chlorostyrene, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, and acrylic acid esters such as alkyl acrylate. Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octyl methacrylate, stearyl methacrylate, glycidyl methacrylate, and alkyl methacrylate can be used. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, maleic acid and the like.

As a vinyl resin having a carboxyl group, styrene having a carboxyl group in its side chain is used.
The general formula of the acrylic ester copolymer resin is shown below.

[0011]

[Chemical 1]

Further, 30% by weight of the following copolymer component is added to 100% by weight of the resin obtained by polymerizing the above monomers.
You may make it contain below. Examples of the copolymerization component include acrylonitrile, maleic acid, maleic acid ester, methyl methacrylate, methyl acrylate, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether. Examples thereof include vinyl monomer components such as vinyl isobutyl ether.

The binder resin used in the toner of the present invention has a molecular weight of 10 ³ especially in GPC chromatogram.
Preferred acrylic acid ester copolymer resin - 10 ⁴ and 10 ⁵ styrene such as those having 10 ⁷ at least one peak located respectively in the region of. This is because the low-molecular weight side has good low-temperature fixability, and the high-molecular weight side has good offset resistance to the fixing roll, whereby the fixing performance on the hot roll is improved. The molecular weight at the peak position of this molecular weight distribution is a value measured by GPC under the following conditions. That is, a solvent (tetrahydrofuran) is caused to flow at a flow rate of 1 ml per minute at a temperature of 25 ° C., and a sample solution dissolved in a tetrahydrofuran solvent at a concentration of 0.4 gr / dl is injected and measured so that the sample weight becomes 8 mg. . The molecular weight of the sample is determined by the calibration curve method. That is, a calibration curve (calibration curve centered on the logarithm of the molecular weight and the count number obtained by GPC) prepared in advance using several kinds of monodisperse polystyrene standard samples is used. In addition, in order to obtain the measurement accuracy, the sample solution dissolved in a tetrahydrofuran solvent is
It was prepared so that the calibration curve was in a linear concentration range. Further, the reliability of the measurement is based on the NBS70 measured under the above measurement conditions.
6 polystyrene standard sample (Mw = 28.8 × 10 ⁴ , M
Mw of n = 13.7 × 10 ⁴ , Mw / Mn = 2.11)
It was confirmed that / Mn was 2.11 ± 0.10.

Styrene having such a molecular weight distribution
The molecular weight of the acrylic ester copolymer resin is GPC
In the chromatogram, it can be adjusted at the stage of synthesis so as to have at least one peak position in each of the molecular weight regions 10 ³ to 10 ⁴ and 10 ⁵ to 10 ⁷ . As another method, a low molecular weight polymer having a peak position at a molecular weight of 10 ³ to 10 ⁴ and a molecular weight of 10 ⁵
To 10 ⁷ may be adjusted by mixing the high molecular weight polymer having a peak position. When adjusting by mixing, paying attention to the fixing property and non-offset property of the toner, the mixing ratio of the low molecular weight polymer and the high molecular weight polymer is from 70:30.
A ratio of 95: 5 is preferred. The ratio of low molecular weight polymer is 9
If it exceeds 5%, a problem of high temperature offset occurs, which is not preferable. On the other hand, if the proportion of the high molecular weight polymer is more than 30%, a large amount of heat energy is required for fixing on the heat fixing roll, which is not preferable.

When the peak position of the high molecular weight polymer is close to 10 ⁵ , the mixing ratio of the high molecular weight polymer is 3
The value is close to 0% and the peak position of the high molecular weight polymer is 10
^{When the} value is close to ⁷ , it is preferable to set the mixing ratio of the high molecular weight polymer to a value close to 5% and control the mixing ratio of the low molecular weight polymer and the high molecular weight polymer because high temperature offset can be prevented.

As the binder resin, in addition to the above-mentioned styrene-acrylic acid ester-based copolymer resin containing a carboxyl group, a polyester resin having a carboxyl group at the terminal is preferable. When a diol is used to obtain the above resin, polyoxypropylene 2,2-2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxy) is used. Phenyl) propane, polyoxyethylene (2,0) 2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,
0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-)
Hydroxyphenyl) propane, ethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol and other diol components Can be used. When using a trihydric or higher polyhydric alcohol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane Triol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-
Methyl propanetriol, 2-methyl-1,2,4-
Butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene and the like are used. As the acid component, fumaric acid, maleic acid, phthalic acid, isophthalic acid, itaconic acid, glutaconic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, alkenylsuccinic acid, 1,2,2, 4-benzenetricarboxylic acid,
2,57-Naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3
-Dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane,
1,2,7,8-octane tetracarboxylic acid etc. are mentioned.

As the binder resin for the electrophotographic toner of the present invention, the above-exemplified copolymers may be mixed and used. In addition, silicone resin, polyamide resin,
You may mix and use resin, such as polyurethane resin.

Further, the toner of the present invention contains a polyethylene wax having at least one peak position of the absorbed heat amount at 85 to 110 ° C. when the absorbed heat amount is measured by DSC (differential scanning calorimeter). Polyethylene wax having a peak position of absorbed heat at a temperature lower than 85 ° C. easily adheres to a collision plate of a crusher such as a jet mill during crushing when a toner for electrophotography is manufactured by a melt kneading method, and thus is suitable for crushing. Is not preferable because it is difficult to obtain the properties and there is a problem in production. Further, there is a problem that the storage stability of the electrophotographic toner is poor. On the other hand, polyethylene wax having a peak position of absorbed heat at a temperature higher than 110 ° C. has no effect of lowering the melting point of the electrophotographic toner,
Fixing at a low fixing temperature is not preferable because sufficient fixing strength on the transfer paper cannot be obtained.

The above polyethylene wax is mainly produced by a low pressure polymerization method using a Ziegler catalyst or a metatheron catalyst, but is not particularly limited to the polyethylene wax obtained by these production methods.
Specific examples of the above polyethylene wax include:
Petrolite from POLYWAX 500, POLY
Waxes commercially available under trade names such as WAX 655 and POLYWAX 850 are mentioned.

As a measuring device for DSC, for example, a differential scanning calorimeter SCS commercially available from Seiko Electronics Co., Ltd.
-5200 is mentioned. As a measuring method, about 5 mg of polyethylene wax is weighed and placed on the DSC, and 1
Blow 50 ml N ² gas per minute. Then, the process of raising the temperature from 20 ° C. to 200 ° C. at a rate of 10 ° C. per minute and then rapidly cooling from 200 ° C. to 20 ° C. is repeated twice, and the peak position of the second absorbed heat amount at that time is measured. Is.

The content of the polyethylene wax in the electrophotographic toner is 0. 0 in the resin component composed of the polyethylene wax and the binder resin constituting the electrophotographic toner.
It is preferably contained in the range of 5 to 50% by weight.
When it is less than 0.5% by weight, the effect of lowering the melting point of the toner is small, and when fixing at a low fixing temperature, it is difficult to obtain sufficient fixing strength on the transfer paper, which is not preferable. On the other hand, if it is more than 50% by weight, the melting point is lowered too much and high temperature offset is likely to occur, which is not preferable.

The peak position of the amount of heat absorbed by DSC is 85
Polyethylene wax having at least one at ˜110 ° C. has a lower softening point than the conventionally used polyolefin wax and has a characteristic of melting sharply with heat. The softening point of can be lowered. For this reason, the polyethylene wax can be sufficiently melted even by a low temperature heat fixing roll, and thus has an excellent effect of non-offset property and fixing strength.

The toner of the present invention contains, in addition to the binder resin and the polyethylene wax described above, a compatibilizing agent composed of a graft polymer of an ethylene glycidyl methacrylate copolymer and a vinyl polymer.

The above graft polymer is contained in the toner for the purpose of improving the compatibility between the carboxyl group-containing resin which is a binder resin and polyethylene. This graft polymer contains an ethylene segment and a vinyl polymer segment. Since the ethylene segment has a high compatibility with the polyethylene wax and the vinyl polymer segment has a high compatibility with the vinyl resin, the compatibility between the polyethylene wax and the vinyl resin can be increased, and the phase separation between the both. Can be prevented. Furthermore, the glycidyl methacrylate contains a glycidyl group. Since this glycidyl group reacts with the carboxyl group to bond, a very preferable compatibility is obtained when the binder resin has a carboxyl group.

By thus allowing the compatible segment and the reactive functional group to exist, the dispersion of the different polymer can be improved. Moreover, since both can react during the melt-kneading, the toner can be easily manufactured.

Specific examples of the above-mentioned graft polymer of ethylene glycidyl methacrylate copolymer and vinyl polymer include MODIPER A manufactured by NOF CORPORATION.
4100 (Graft polymer of ethylene glycidyl methacrylate copolymer and polystyrene, composition ratio: 7
0/30), MODIPER A4200 (graft polymer of ethylene glycidyl methacrylate copolymer and polymethyl methacrylate, composition ratio: 70/30),
A graft polymer commercially available under the trade name of Modiper A4400 (a graft polymer of ethylene glycidyl methacrylate copolymer and an acrylonitrile-styrene copolymer, composition ratio: 70/30) can be exemplified.

In the toner of the invention, in addition to the above components, a resin, a colorant, a magnetic substance, and a property improving agent such as a charge control agent and a fluidizing agent can be used.

As the colorant, carbon black,
Nigrosine dye, aniline blue, chalco oil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, mixtures thereof, and the like. it can. It is necessary that these colorants be contained in a sufficient ratio so that a visible image having a sufficient density is formed, and the ratio is usually about 1 to 20 parts by weight with respect to 100 parts by weight of the binder resin. To be done.

The magnetic substance is a metal, alloy, or a compound containing these elements, such as ferrite, magnetite or other iron, cobalt, nickel, or the like, which exhibits ferromagnetism, or a compound containing no such element, but a suitable heat treatment. Alloys which exhibit ferromagnetism when subjected to, for example, manganese-copper-aluminum, manganese-copper-tin alloys of the type called Heusler alloys containing manganese and copper, or chromium dioxide, and the like. You can 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 micron. The content is 20 to 70 parts by weight per 100 parts by weight of toner,
It is preferably 40 to 70 parts by weight.

Examples of the property improving agent include a charge control agent, an offset preventing agent, a fluidity improving lubricant, and the like.

When attention is paid to the melting characteristics of the toner, it is desired to improve the fixing property at a lower temperature. For that purpose, especially the melting start temperature of the toner is 60 ° C. to 100 ° C.
It is preferably in the range of. If it is higher than 100 ° C., the fixing property is not sufficient, and if it is lower than 60 ° C., the blocking property may be deteriorated and a problem may occur in the storage stability, which is not preferable.

The above-mentioned melting start temperature means the starting temperature of falling of the plunger under the following measurement conditions. Measuring instrument; Shimadzu's advanced flow tester CF-500 Measuring condition: Plunger: 1 cm ² Die diameter: 1.0 mm Die length: 1.0 mm Load: 20 KgF Preheating temperature: 50-80 ° C Preheating time: 300sec heating rate: 6 ° C / min

The electrophotographic toner of the present invention having the above structure can be mixed with a carrier made of ferrite powder, iron powder or the like to form a two-component developer. When the toner itself contains a magnetic material, it can be used as a one-component developer as it is without being mixed with a carrier. Further, it can be applied as it is as a non-magnetic one-component developer.

[0034]

The electrophotographic toner of the present invention comprises a binder resin composed of a polymer having a carboxyl group, and a peak of heat absorbed by DSC in the range of 85 to 110 ° C. of at least 1.
Existing polyethylene wax, and a graft polymer of ethylene glycidyl methacrylate copolymer and vinyl polymer as a compatibilizer. By adding the graft polymer to the toner, the dispersibility of the polyethylene wax in the carboxyl group-containing binder resin is improved.

[0035]

EXAMPLES The present invention will be described below based on examples. In the examples, "part" means "part by weight". (Example 1) 10 parts by weight of a styrene-butyl acrylate-acrylic acid copolymer (A) having a weight average molecular weight of 9 × 10 ⁵ and a number average molecular weight of 3.9 × 10 ⁵ , and a weight average molecular weight of 8 × 10 ³ and number average molecular weight of 2.7 × 1
90 parts of a styrene-butyl acrylate-acrylic acid copolymer (B) of 0 ³ was mixed to obtain a styrene-acrylic acid ester copolymer. During the polymerization, the blending amount of acrylic acid in the copolymer was 10% by weight. The peak positions of the molecular weight in the GPC chromatogram of the obtained copolymer were at 7.5 × 10 ⁵ and 4.5 × 10 ³ .

[0036]

The raw materials having the above blending ratios are mixed in a super mixer, melted and kneaded by a twin-screw kneader, ground by a jet mill, and then classified by a dry air stream classifier to obtain particles having an average particle diameter of 10 μm. Obtained. And 100 parts of the particles and hydrophobic silica (manufactured by Cabot Corporation, trade name: CABOSIL T
0.4 part of S-530) is stirred in a Henschel mixer for 1 minute to adhere hydrophobic silica to the surface of the particles,
An electrophotographic toner of this example was obtained.

(Example 2) The raw materials having the above blending ratios are mixed with a super mixer, hot melt kneaded with a twin-screw kneader, pulverized with a jet mill, and then classified with a dry air stream classifier to obtain an average particle diameter of 10
Particles of μm were obtained. And 100 parts of the particles and hydrophobic silica (manufactured by Cabot Corporation, trade name: CABOSIL TS-53)
0) 0.4 part was stirred for 1 minute in a Henschel mixer, and hydrophobic silica was attached to the surface of the particles to obtain an electrophotographic toner of this example.

(Example 3) The raw materials having the above blending ratios are mixed with a super mixer, hot melt kneaded with a twin-screw kneader, pulverized with a jet mill, and then classified with a dry air stream classifier to obtain an average particle diameter of 10
Particles of μm were obtained. And 100 parts of the particles and hydrophobic silica (manufactured by Cabot Corporation, trade name: CABOSIL TS-53)
0.4 parts of 0) was stirred for 1 minute in a Henschel mixer, and hydrophobic silica was adhered to the surface of the particles to obtain the electrophotographic toner of the present invention.

Comparative Example 1 The weight average molecular weight is 8.5 × 1.
0 is ^5, the number-average molecular weight of 3.6 × 10 ⁵ and a styrene - butyl acrylate copolymer (C) 10 parts of a weight average molecular weight of 7.9 × 10 ^3, the number average molecular weight of 2 90 parts of styrene-butyl acrylate copolymer (D) of 0.7 × 10 ³ was mixed to obtain a styrene-acrylic acid ester copolymer having no carboxyl group. The peak of the molecular weight in the GPC chromatogram of the obtained copolymer was present at 7.1 × 10 ⁵ and 4.6 × 10 ³ . A comparative electrophotographic toner was obtained in the same manner except that the styrene-acrylic acid ester copolymer resin of Example 1 was replaced with the above polymer.

Comparative Example 2 A comparative electrophotographic toner was obtained in the same manner as in Example 1 except that the graft polymer of the ethylene glycidyl methacrylate copolymer and polystyrene was not contained.

(Comparative Example 3) Polyethylene was used as polypropylene (manufactured by Sanyo Chemical Industry Co., Ltd., trade name: Viscole 330P,
The temperature at which the peak of absorption heat by DSC is located is 145
C. and 154 ° C., which is polypropylene having two peaks), and a comparative electrophotographic toner was obtained in the same manner as in Example 1.

Next, the melting start temperature of the electrophotographic toners obtained in the above Examples and Comparative Examples was measured under the above-mentioned measurement conditions using a high-performance flow tester manufactured by Shimadzu Corporation.

Next, the fixing strength of the toner was also tested. First, 3 parts of each of the obtained electrophotographic toners and 100 parts of a non-coated ferrite carrier (manufactured by Powder Tech Co., trade name; FL-1020) were mixed to prepare a developer. Next, using the developer, a plurality of belt-shaped unfixed images each having a length of 2 cm and a width of 5 cm were formed on an A4 copy paper by a commercially available copying machine (trade name: SF-9800 manufactured by Sharp Corporation). Next, using a fixing device including a heat fixing roll having a surface layer made of Teflon and a pressure fixing roll having a surface layer made of silicone rubber, a roll pressure of 5 Kg / cm.
^{2. The} roll speed was adjusted to 100 mm / sec and the set temperature of the heat fixing roll was adjusted to 130 ° C., and the toner image on the transfer paper having the unfixed image was fixed. Then, after the image density of the formed fixed image was measured using a Macbeth reflection densitometer (RD-914), the image density was measured again by rubbing with a cotton pad. The fixing results were calculated by applying the measurement results to the following formula and used as an index of low energy fixing property. Image density of fixed image after rubbing / image density of fixed image before rubbing × 100 (%)

Further, each of the above-mentioned developing agents is used to obtain 1000 by a commercially available copying machine (manufactured by Toshiba Corporation, trade name: BD-3801).
A continuous copy test up to 0 sheets was performed. Image densities before and after this continuous copy test were measured as described above. At the same time, the difference in whiteness between the transfer paper before copying and the non-image area after copying is measured by a color difference meter (manufactured by Nippon Denshoku Co., Ltd., trade name: MODELZ-
1001DP) and used as an index of ground fog.

Table 1 shows the results of the examples and comparative examples obtained by the above test.

[0047]

As is clear from the results shown in Table 1, the electrophotographic toner of this example contains a binder resin composed of a styrene-acrylic acid ester-based copolymer having a carboxyl group,
Since it contains at least one polyethylene wax having a peak of absorbed heat by DSC in the range of 89 to 103 ° C. and a graft polymer of ethylene glycidyl methacrylate copolymer and polystyrene as a compatibilizing agent, Even at a low temperature of 130 ° C., the fixing temperature was 85% or more, and the result of the continuous copy test of 10,000 sheets was also good. On the other hand, the electrophotographic toners obtained in Comparative Examples do not contain a binder resin and a compatibilizing agent for improving the compatibility with the wax, so that the image density is reduced in the 10,000 copy test. It has been confirmed that there is a problem in practical use, since the fogging also increased, and the fluidity of the toner was poor, and the toner sometimes caused a bridge phenomenon in the toner hopper, which made it impossible to replenish the toner. In particular, it was confirmed that the electrophotographic toner of Comparative Example 3 had a low fixing strength and had a problem.

[0049]

The electrophotographic toner of the present invention comprises a binder resin composed of a polymer having a carboxyl group, a polyethylene wax having a peak of absorbed heat by DSC in the range of 85 to 110 ° C., and a polyethylene wax. It contains an ethylene glycidyl methacrylate copolymer and a graft polymer of a vinyl polymer as a solubilizer. By adding the graft polymer to the toner, the dispersibility of the polyethylene wax in the carboxyl group-containing binder resin is improved. Therefore, the electrophotographic toner of the present invention has sufficient fixing strength even when the temperature of the heat fixing roll is low, and when applied by a copying machine or a printer, the power consumption can be reduced and the low roll pressure can be applied. This brings about effects such as reduction of machine cost and increase of copying speed.

Claims (5)

[Claims] 1. A binder resin made of a polymer having a carboxyl group and a peak of absorbed heat by DSC of 85 to 85.
An electrophotographic toner comprising at least one polyethylene wax present in the range of 110 ° C. and a graft polymer of an ethylene glycidyl methacrylate copolymer and a vinyl polymer as a compatibilizing agent. 2. The toner for electrophotography according to claim 1, wherein the content of polyethylene wax in the resin component is 0.5 to 50% by weight. 3. The carboxyl group-containing polymer is a styrene-acrylic acid ester copolymer resin, and the peak positions of the molecular weight in the GPC chromatogram are 10 ³ to 10 ⁴ and 10 ⁵ to 10 ⁷ , respectively. 2. The toner for electrophotography according to claim 1, wherein at least one is present in the toner. 4. The toner for electrophotography according to claim 1, wherein the polymer containing a carboxyl group is polyester. 5. The melting start temperature of the toner is 60 to 100 ° C.
The toner for electrophotography according to claim 1, wherein: