JPH08194327A - Heat fixable electrophotographic developer - Google Patents

Abstract

PURPOSE: To obtain a developer excellent in releasability, blocking resistance and fixability at the time of low energy fixation, not causing offsetting phenomenon and capable of preventing the contamination of a carrier, a photoreceptor, a heating roll, etc., by using an ethylene copolymer having a specified compsn. and a specified mol.wt. as wax to be added to an electrostatic toner. CONSTITUTION: This developer contains ethylene copolymer wax (A) made of a copolymer of ethylene with at least one of unsatd. carboxylic acid and unsatd. carboxylic ester and having 90-99.9mol% ethylene unit content and a number average mol.wt. Mn of 300-8,000, a binder (B) and a colorant (C). The ethylene unit content of the wax A is preferably 92-99mol% and the number average mol.wt. Mn of the wax A is preferably 500-6,000, more preferably 500-4,000. The mol.wt. distribution (Mw/Mn) is usually 2.0-6.0 and the crystallinity is usually 10-55%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-fixing type electrophotographic developer, and in particular, as a main component of an electrostatic toner, a toner having excellent releasability and blocking resistance during heat-fixing can be obtained. The present invention relates to a heat fixing type electrophotographic developer which does not cause an offset phenomenon and does not contaminate a carrier, a photoconductor, a heating roller and the like.

[0002]

2. Description of the Related Art An electrophotographic developer, so-called electrostatic toner, is used in electrostatic electrophotography to develop a latent image formed by charging exposure to form a visible image. This electrostatic toner is a chargeable fine powder obtained by dispersing a coloring agent such as carbon black or pigment in a resin. This electrostatic toner is a dry two-component toner used together with a carrier such as iron powder or glass particles, a wet toner dispersed using an organic solvent such as isoparaffin, and a dry toner in which magnetic fine powder is dispersed. It is roughly classified into one-component toners.

By the way, an image obtained by developing on a photoconductor with electrostatic toner is transferred to paper, and an image obtained by direct development on a paper having a photosensitive layer formed thereon remains as it is. And is fixed by solvent vapor. Among them, the fixing by the heating roller is a contact-type fixing method, so that it has high heat efficiency, can reliably fix an image even by a heat source at a relatively low temperature, and has an advantage that it is suitable for high-speed copying. are doing.

In particular, in recent years, the range of use of electrophotography has expanded, and the need for fixing electrostatic toner with lower energy than ever has been increasing. For example, as the use of electrophotography in household appliances has advanced, it has been required to reduce the power consumption of the heating roller unit. Further, improvement in high-speed fixing property is required as a toner used for an output terminal of a high-speed device such as a computer. However, when the conventional electrostatic toner is used when fixing an image by contacting a heating body such as a heating roller, a phenomenon in which a part of the toner adheres to the heating body and is transferred to the subsequent image portion, a so-called offset phenomenon May occur. In particular, when the temperature of the heating roller is low, the electrostatic toner cannot be sufficiently softened, and the fixing property to printing paper or a film is deteriorated, and at the same time, an offset phenomenon is likely to occur. Further, in the case of copying at a high speed, if the heating element is heated to a high temperature in order to improve the fixing effect and the fixing speed, it may cause an offset phenomenon. Therefore, the offset phenomenon is solved by, for example, impregnating the surface of the heating roller with silicone oil or supplying the surface of the heating roller with silicone oil. However, on the contrary, there may occur a problem such that the heating roller becomes dirty.

Further, various thermoplastic resins are used as a binder which is a component of the electrostatic toner, and in particular, a low molecular weight styrene / (meth) acrylic acid ester copolymer has a good chargeability and is 100 It has an appropriate softening point around ℃, which makes it easy to fix, easy to clean the photoreceptor and less polluting, low hygroscopicity, good compatibility with carbon black as a coloring agent, and easy to pulverize. It is widely used because of its features. However, conventional electrostatic toners using this low molecular weight styrene / (meth) acrylic acid ester copolymer as a binder can also be fixed by a low temperature heating roller,
Alternatively, in high-speed copying, there is a problem that an offset phenomenon is likely to occur.

In order to solve the above-mentioned problems, it has been proposed to add a polyolefin wax to an electrostatic toner as a releasing agent (Japanese Patent Publication No. 52-3304 / 52-52).
No. 3305, No. 57-52574, No. 58-
58664, JP-A-58-59455).

[0007]

However, even in the electrostatic toner to which the above-mentioned polyolefin wax is added as a release agent, even under the recent severe low-energy fixing condition, good fixing property is exhibited and the offset phenomenon is caused. It has not yet been prevented. Still, in the above-mentioned conventional technique, another problem may occur other than the offset phenomenon. For example, a toner to which a polyolefin wax is added may have a low blocking resistance, may cause blocking of the toner in the toner cartridge, and the toner may not be supplied from the toner cartridge onto the photoreceptor.
Further, a phenomenon in which a low-crystalline substance contained in the polyolefin wax adheres to the surface of the carrier, the photoconductor, the heating rochler, or so-called filming phenomenon occurs, and an electrostatic latent image is formed on the photoconductor, or a toner is formed. May adversely affect the charging of the image, and the resulting image may be significantly disturbed.

Therefore, an object of the present invention is to use it as a main component of an electrostatic toner, which is excellent in releasability at the time of low-energy fixing, and is also excellent in blocking resistance and fixing property, and does not cause an offset phenomenon. It is an object of the present invention to provide a heat fixing type electrophotographic developer which does not contaminate a carrier, a photoconductor, a heating roller and the like.

[0009]

In order to solve the above problems, the inventors of the present invention have earnestly studied, and as a result, as a wax to be added to an electrostatic toner, an ethylene copolymer having a specific composition and molecular weight. The inventors have found that the above problems can be solved by using, and have reached the present invention.

That is, the present invention is a copolymer of ethylene and at least one kind selected from unsaturated carboxylic acids and unsaturated carboxylic acid esters, wherein the content of ethylene units is 90 to 99.9 mol%. And a heat fixing type electrophotographic developer containing an ethylene copolymer wax (A) having a number average molecular weight (Mn) of 300 to 8000, a binder (B) and a colorant (C). Is.

The heat-fixing type electrophotographic developer of the present invention (hereinafter referred to as "the developer of the present invention") will be described in detail below.

The ethylene copolymer wax (A) which is the main component of the developing material of the present invention is a copolymer of ethylene and at least one selected from unsaturated carboxylic acids and unsaturated carboxylic acid esters. . Examples of unsaturated carboxylic acids include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and maleic anhydride. Further, as the unsaturated carboxylic acid ester, methyl acrylate,
Ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, acrylic acid 2
-Ethylhexyl, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-methacrylate
Propyl, n-butyl methacrylate, 2-methacrylic acid
Unsaturated monocarboxylic acid esters such as ethylhexyl, ethyl maleate, propyl maleate, butyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, ethyl fumarate, propyl fumarate,
Examples thereof include unsaturated dicarboxylic acid esters such as butyl fumarate, diethyl fumarate, dipropyl fumarate, dibutyl fumarate, dipropyl itaconic acid and dibutyl itaconic acid. These unsaturated carboxylic acids or unsaturated carboxylic acid esters may be contained in the ethylene copolymer (A) alone or in combination of two or more.
Among these, acrylic acid ester and methacrylic acid ester are preferable. In particular, methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate are preferable.

In the present invention, the ethylene copolymer wax (A) has an ethylene unit content of 90-9.
9.9 mol%, and particularly preferably 92 to 99 mol%.

This ethylene copolymer wax (A)
Has a number average molecular weight (Mn) of 300 to 8000, preferably 500 to 6000, and more preferably 500 to 4000. In addition, the molecular weight distribution (M
w / Mn) is usually 2.0 to 6.0. In the present invention, the number average molecular weight (Mn) or the molecular weight distribution (Mw)
/ Mn) is a value determined by gel permeation chromatography (GPC) in terms of monodisperse polystyrene using a calibration curve prepared in advance using monodisperse polystyrene.

The crystallinity of the ethylene copolymer wax (A) is usually 10 to 55%. Here, the crystallinity is a value measured by an X-ray diffraction method.

Further, the melting point of the ethylene copolymer wax (A) is usually about 80 to 115 ° C., and the heat of fusion is usually about 10 to 35 Cal / g. Here, the melting point and the heat of fusion are values measured by a differential scanning calorimeter (DSC).

Furthermore, the density of the ethylene copolymer wax (A) is usually 0.91 to 0.95 g / c.
m ³ and the softening point is usually about 85 to 125 ° C. In the present invention, the density is JIS K6760.
The softening point is measured according to JIS
It is a value measured according to K2207.

In the developer of the present invention, the ethylene copolymer wax (A) may be used alone or in combination of two or more.

This ethylene-based copolymer wax (A) is manufactured by the above-mentioned ethylene unit content and number average molecular weight (M
There is no particular limitation as long as it is a method capable of producing n) and the ethylene copolymer wax (A) having other characteristics. For example, ethylene is copolymerized with ethylene and at least one kind selected from the unsaturated carboxylic acids and unsaturated carboxylic acid esters by a high pressure radical method or a medium and low pressure method using a transition metal catalyst such as a Ziegler catalyst. A method for directly producing an ethylene copolymer wax (A), or a high pressure radical method using ethylene and at least one selected from the above unsaturated carboxylic acids and unsaturated carboxylic acid esters, or a transition metal such as a Ziegler catalyst. Copolymerized by a medium and low pressure method using a catalyst,
A high molecular weight copolymer having the same ethylene unit content as the ethylene copolymer wax is produced, and the high molecular weight copolymer is heat-degraded to obtain the specific number average molecular weight (Mn). ) Etc., the ethylene-based copolymer wax (A) can be prepared according to the method for producing the wax. Among these methods, the ethylene copolymer wax (A) having a low content of low crystalline components and a relatively narrow molecular weight distribution can be produced in high yield and high efficiency. And at least one kind selected from the above-mentioned unsaturated carboxylic acid and unsaturated carboxylic acid ester by copolymerization by a high pressure radical method,
A method of producing a high molecular weight copolymer and further heating and degrading the high molecular weight copolymer to produce an ethylene copolymer wax is preferable. When a copolymer of a high molecular weight ethylene and an unsaturated carboxylic acid ester is heat-degraded, a part of the carboxylic acid ester unit may change to a carboxylic acid unit.

As a method of heating and degrading the high molecular weight ethylene copolymer, for example, the high molecular weight ethylene copolymer is fed to an extruder having one or more axes and melt-kneaded. While extruding, a method of directly feeding a high molecular weight ethylene copolymer to a tubular reactor, a tank reactor, etc. to heat and degrade it, or supplying a high molecular weight ethylene copolymer to an extruder. Then, a method of continuously extruding while melt-kneading, supplying to a tubular reactor and heating and degrading, and the like can be mentioned. The heating temperature in the extruder or reactor is 3
It is 50 to 450 ° C, preferably 380 to 430 ° C.
Among these methods, a high molecular weight ethylene copolymer is supplied to an extruder and continuously extruded while melt-kneading,
A method of supplying to a tubular reactor and heating and degrading is preferable. Further, it is preferable that the heating degradation is performed in an inert atmosphere such as nitrogen.

In the present invention, the ethylene copolymer wax (A) is a modified product obtained by modifying a polymerizable monomer such as maleic anhydride or styrene by graft copolymerization, or potassium or sodium. Alternatively, a metal cross-linked product obtained by reacting with a metal compound such as calcium may be used.

The binder which is the component (B) of the developing material of the present invention may be any as long as it is made of a thermoplastic resin blended in this type of heat fixing type electrophotographic developing material. , Not particularly limited. For example, styrene polymer, ketone resin, maleic acid resin, aliphatic polyester resin,
Examples include aromatic polyester resins, coumarone resins, phenol resins, epoxy resins, terpene resins, polyvinyl butyral, polybutyl methacrylate, polyvinyl chloride, polyethylene, polypropylene, polybutadiene, ethylene-vinyl acetate copolymers and the like. Among these, the styrene-based polymer is preferable because it has an appropriate softening point around 100 ° C. and exhibits good fixability.

Examples of the styrene-based polymer include:
Examples thereof include a polymer composed only of a styrene-based monomer or a copolymer of a styrene-based monomer and another vinyl-based monomer. Styrene-based monomers include styrene and p-
Examples include chlorostyrene and vinylnaphthalene. Further, as the other vinyl-based monomer, for example, ethylene,
Ethylenically unsaturated monoolefins such as propylene, 1-butene and isobutene; vinyl halides such as vinyl chloride, vinyl bromide and vinyl fluoride; vinyl such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl acetate. Esters; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-acrylate
Esters of α-methylene aliphatic monocarboxylic acids such as chloro-ethyl, phenyl acrylate, α-chloroacrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate; nitriles such as acrylonitrile, methacrylonitrile and acrylamide Or amides; vinyl methyl ether, vinyl ethyl ether,
Vinyl ethers such as vinyl propyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone and the like Examples thereof include N-vinyl compounds. Among these vinyl monomers, esters of α-methylene aliphatic monocarboxylic acid are preferable.

Among these styrene polymers, those having a number average molecular weight (Mn) of 2000 or more are preferable.
Particularly, those having a number average molecular weight (Mn) of 3,000 to 30,000 are preferable. Further, the styrene-based polymer preferably has a styrene content of 25% by weight or more.

The colorant which is the component (C) of the developer of the present invention may be any one as long as it is blended with this type of heat-fixing type electrophotographic developer, and is not particularly limited. Examples include pigments or dyes such as carbon black, phthalocyanine blue, aniline blue, alcohol oil blue, chrome yellow, ultramarine blue, quinoline yellow, lamp black, rose bengal, diazo yellow, rhodamine B lake, carmine 6B, and quinacridone derivative. These may be used alone or in combination of two or more.

The colorant (C) includes azine type nigrosine, indulin, azo type dye, anthraquinone type dye, triphenylmethane type dye, xanthene type dye, phthalocyanine type dye, etc. for the purpose of complementary color and charge control. You may mix an oil-soluble dye.

In the developing material of the present invention, the mixing ratio of the ethylene copolymer wax (A), the binder (B) and the colorant (C) is usually ethylene copolymer wax (A) / The weight ratio of the binder (B) / colorant (C) is about 1 to 20/100/1 to 20, preferably about 1 to 10/100/1 to 10.

In addition to the wax (A), the binder (B) and the colorant (C), the developer of the present invention may contain other components as long as the effects of the present invention are not impaired. Good. For example, a charge control material, a plasticizer, a release agent such as wax, and the like may be appropriately mixed.

The developer of the present invention is a two-component electrostatic toner,
It is used as the main component of any electrostatic toner such as a one-component electrostatic toner.

When the developer of the present invention is used as a main component of a two-component electrostatic toner, the two-component electrostatic toner is obtained by using the ethylene copolymer wax (A), the binder (B),
Colorant (C) and, if necessary, other components,
After mixing by a known method using a ball mill, an attritor, etc., they are kneaded by using a heating two-roll, a heating kneader, an extruder and the like, and cooled and solidified. Further, the obtained solidified product is roughly crushed by using a hammer mill, a crusher or the like, and then finely pulverized by a jet mill, a vibration mill, or by adding water to a ball mill, an attritor or the like to obtain an average particle size of 5 to 35 μm. It can be prepared by adding a carrier to the product.
The carrier used may be a known carrier and is not particularly limited. For example, silica sand having a particle size of 200 to 700 μm, glass beads, iron balls, or magnetic material powder of iron, nickel, cobalt, or the like can be used.

The blending amount of the ethylene copolymer wax (A) in this two-component electrostatic toner is 1 to 20 parts by weight, preferably 100 parts by weight of the thermoplastic resin including the binder (B). Is an amount of 2 to 10 parts by weight.

When the developer of the present invention is used as a one-component electrostatic toner, the one-component electrostatic toner requires a wax (A), a binder (B), a colorant (C), and others. The additive, the other thermoplastic resin and the magnetic material powder, which are blended according to the above, can be prepared by treating them in the same manner as in the preparation of the two-component electrostatic toner.

The blending amount of the ethylene copolymer wax (A) in this one-component electrostatic toner depends on the binder (B) 1
1 to 20 parts by weight, preferably 1 to 1 relative to 00 parts by weight
The amount is 0 parts by weight.

As the magnetic material powder to be blended with the one-component electrostatic toner, a magnetite fine powder having a particle size of 1 μm or less is usually used, but metals such as cobalt, iron and nickel, alloys thereof, Powders such as oxides, ferrite and mixtures thereof can also be used. The blending amount of the magnetic material powder in the one-component electrostatic toner is such that the electric resistance of the obtained electrostatic toner does not decrease, the charge retention of the electrostatic toner is good, and the image does not bleed.
Moreover, since the softening point is maintained in an appropriate range, the fixing can be suitably performed, the required charge value can be obtained, and the scattering is difficult to occur. Usually, the total amount of the binder (B) and the magnetic material powder is The amount is 40 to 120 parts by weight of the magnetic material powder with respect to 100 parts by weight. Further, a known charge control agent may be added to the two-component electrostatic toner or the one-component electrostatic toner, if necessary.

Further, the ethylene copolymer wax (A), which is the main component of the developer of the present invention, can be easily made into a fine particle water dispersion by itself or by adding an emulsifier such as a surfactant. Therefore, it can be preferably used as one component of a so-called polymerized toner.

[0036]

EXAMPLES Examples and comparative examples of the present invention will be given below.
The present invention will be specifically described, but these examples do not limit the scope of the present invention in any way.
In the examples and comparative examples, the number average molecular weight (Mn) and the molecular weight distribution (Mw) of the ethylene-based copolymer wax are
/ Mn), crystallinity, melting point, heat of fusion and softening point, and fixing property of two-component electrostatic toner in toner characteristic evaluation, blocking resistance, offset phenomenon, image disturbance, and photoreceptor, heating Evaluation of the stain resistance of the roller was performed according to the following method.

Number-Average Molecular Weight (Mw) and Molecular Weight Distribution (Mw / Mn) Using o-dichlorobenzene as a solvent, a solution sample of an ethylene copolymer wax having a concentration of 0.1% by weight was prepared. This sample is used as a column for GMH- manufactured by Tosoh Corporation.
The measurement was performed at a temperature of 140 ° C. and a measurement flow rate of 1.0 ml / min by a gel permeation chromatography device (GPC150C manufactured by Waters) using an HT (60 cm) and a GMH-HTL (60 cm) connected. The number average molecular weight (Mn) and the molecular weight distribution (Mw / Mn) in terms of polystyrene were determined by a calibration curve prepared in advance using a monodisperse polystyrene standard sample.

Crystallinity The ethylene copolymer wax is added at 180 ° C. for 10 minutes,
After press-molding with a load of ² kg / cm ² , the sheet-shaped sample having a thickness of 1 mm was prepared by cooling. This sheet-shaped sample was placed on an X-ray diffractometer (Rigaku Denki Co., Ltd., Rotaflex Ru300, Cu target) to obtain a tube voltage of 60 k.
X-ray diffraction was measured by a transmission method at V and a tube current of 300 mA. The X-ray diffraction chart was drawn and the crystallinity was calculated by the Natta method.

Melting point and heat of fusion Using a differential scanning calorimeter (DSC), a heating rate of 10 ° C. /
It was measured at min.

Softening point Measured according to JIS K2207. Fixability of Fixed Image A test image was copied and developed on a selenium photoreceptor by electrophotography using a two-component electrostatic toner. A fixing roller having the obtained image transferred to a transfer paper and having a surface formed of polytetrafluoroethylene (manufactured by DuPont),
The surface is silicon rubber (Ke-130 manufactured by Shin-Etsu Chemical Co., Ltd.
The image was fixed by adjusting the temperature of the fixing roller to 200 ° C. using a pressure-bonding roller formed at 0 RTV). Then, the surface of the obtained fixed image was rubbed 5 times with a sand eraser having a bottom of 15 mm × 7.5 mm on which a load of 500 g was placed, and before and after that, the optical reflection density of the surface was measured with a reflection densitometer of Macbeth. Then, the image residual rate defined by the following formula was determined and used as an index of fixability.

Image residual rate (%) = (image density after rubbing)
/ (Image density before rubbing) x 100

Blocking Resistance of Toner 100 g of the two-component electrostatic toner was placed in a polyethylene container having a capacity of 500 ml, shaken for 30 minutes, and then allowed to stand at 60 ° C. for 50 hours. Then, the temperature was returned to room temperature and the blocking state was examined. The blocking state was visually evaluated according to the following evaluation criteria to evaluate the blocking resistance.

◎ No blocking at all. ○ There is some blocking that can be easily loosened by hand. △ There is quite a lot of blocking that can be easily loosened by hand. × There are many lumps that cannot be completely loosened by hand.

Offset phenomenon, image disturbance, and contamination of photoreceptor / fixing roller A two-component electrostatic toner was used to copy and develop a test image on a selenium photoreceptor by electrophotography. The obtained image was transferred to a transfer paper, the surface of which was formed of polytetrafluoroethylene (manufactured by DuPont) at 200 ° C., and the surface of which was silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd., KE-1).
The copying process of fixing the image was repeated using a pressure roller formed at 300 RTV). After the copying process was repeated 5000 times, the presence or absence of an offset phenomenon, the presence or absence of image disturbance, and the stain resistance of the surface of the photoconductor / fixing roller were visually inspected and evaluated according to the following criteria.

Offset Phenomenon, Distortion of Image ○ There was no offset phenomenon or image disturbance. Fairly slight offset phenomenon and image disturbance occurred. × The offset phenomenon or image distortion is quite severe.

Contamination of the surface of the photoconductor / fixing roller ◎ The surfaces of the photoconductor and the fixing roller are not soiled at all. ○ There is very little stain on the surface of the photoconductor or the fixing roller. B: Some stain was found on the surface of the photoconductor or the fixing roller. × The surface of the photoconductor or the fixing roller is considerably dirty.

Example 1 [Production of Ethylene Copolymer Wax] A high molecular weight ethylene / methacrylic acid copolymer (Mn: 13200, obtained by copolymerizing ethylene and methacrylic acid by a high-pressure radical method).
Methacrylic acid content: 1.3 mol%, crystallinity: 48
%, Hereafter referred to as "PO-1") is supplied to an extruder and melt-kneaded at a screw rotation speed of 50 rpm to be extruded while being supplied to a heat-degrading pipe (inner diameter: 20 mmφ).
By heating and degrading at 0 ° C., an ethylene / methacrylic acid copolymer wax was produced. The number average molecular weight (Mn), molecular weight distribution (Mw / Mn), crystallinity, melting point, heat of fusion, and density of the obtained ethylene / methacrylic acid copolymer wax (hereinafter referred to as "PW-1") were measured. did. The results are shown in Table 1.

[Preparation of Toner] Styrene / acrylic acid n
-Butyl copolymer (manufactured by Sanyo Kasei Co., Ltd., Hymer S
EM-73F) 85 parts by weight, PW-1 4 parts by weight, carbon black (manufactured by Mitsubishi Kasei Kogyo, diamond black SH)
9 parts by weight and 2 parts by weight of a metal-containing dye (BASF Co., Ltd., Zabon Fast Black B) were supplied to a ball mill to obtain 2
Mix for 4 hours. Next, the mixture was kneaded with a hot roll, cooled, pulverized and classified to prepare a developing material having an average particle diameter of 13 to 15 μm.

Two-component electrostatic toner was prepared by mixing 100 parts by weight of iron powder having an average particle size of 50 to 80 μm as a carrier with 120 parts by weight of this developer. With respect to this two-component electrostatic toner, the fixability of a fixed image, the blocking resistance of the toner, the offset phenomenon, the disorder of the image, and the stain resistance of the photoconductor / fixing roller were evaluated.
The results are shown in Table 1.

(Example 2) Instead of PO-1, a high molecular weight ethylene / methacrylic acid copolymer (Mn: 9000,
Methacrylic acid content: 3.2 mol%, crystallinity: 39
%, Hereinafter referred to as “PO-2”) was heat-degraded at 430 ° C. to produce an ethylene / methacrylic acid copolymer wax (hereinafter referred to as “PW-2”) in the same manner as in Example 1. , Its number average molecular weight (Mn), molecular weight distribution (Mw
/ Mn), crystallinity, melting point, heat of fusion, and density were measured. The results are shown in Table 1.

A two-component electrostatic toner was prepared in the same manner as in Example 1 except that PW-2 was used instead of PW-1, and the fixability of the fixed image, toner blocking resistance, and offset phenomenon were observed. , The image disturbance, and the contamination of the photoconductor / fixing roller were evaluated. The results are shown in Table 1.

(Example 3) Instead of PO-1, high molecular weight ethylene / ethyl acrylate copolymer (Mn: 176)
00, ethyl acrylate content: 2.6 mol%, crystallinity: 41%, hereinafter referred to as “PO-3”) was heat-degraded at 425 ° C. and ethylene.
Ethyl acrylate copolymer wax (hereinafter referred to as "PW-
3 ”), and its number average molecular weight (Mn), molecular weight distribution (Mw / Mn), crystallinity, melting point, heat of fusion,
And the density was measured. The results are shown in Table 1.

A two-component electrostatic toner was prepared in the same manner as in Example 1 except that PW-3 was used instead of PW-1, and the fixability of the fixed image, toner blocking resistance, and offset phenomenon were observed. , The image disturbance, and the contamination of the photoconductor / fixing roller were evaluated. The results are shown in Table 1.

(Example 4) Instead of PO-1, a high molecular weight ethylene / methyl methacrylate copolymer (Mn: 85
00, methyl methacrylate content: 3.5 mol%, crystallinity: 45%, hereinafter referred to as “PO-4”) 420 ° C.
Ethylene / ethyl acrylate copolymer wax (hereinafter referred to as "PW-
4 ”), and its number average molecular weight (Mn), molecular weight distribution (Mw / Mn), crystallinity, melting point, heat of fusion,
And the density was measured. The results are shown in Table 1.

A two-component electrostatic toner was prepared in the same manner as in Example 1 except that PW-4 was used in place of PW-1, and the fixability of the fixed image, toner blocking resistance, and offset phenomenon were observed. , The image disturbance, and the contamination of the photoconductor / fixing roller were evaluated. The results are shown in Table 1.

(Comparative Example 1) An ethylene / methacrylic acid copolymer wax (hereinafter referred to as "PW-5") was prepared in the same manner as in Example 1 except that PO-1 was heat-degraded at 370 ° C.
And the number average molecular weight (Mn) and molecular weight distribution (M
w / Mn), crystallinity, melting point, heat of fusion, and density were measured. The results are shown in Table 1.

A two-component electrostatic toner was prepared in the same manner as in Example 1 except that PW-5 was used instead of PW-1, and the fixability of the fixed image, toner blocking resistance, and offset phenomenon were observed. , The image disturbance, and the contamination of the photoconductor / fixing roller were evaluated. The results are shown in Table 1.

Comparative Example 2 An ethylene / methacrylic acid copolymer wax (hereinafter referred to as "PW-6") was prepared in the same manner as in Example 1 except that PO-1 was heat-degraded at 425 ° C.
And the number average molecular weight (Mn) and molecular weight distribution (M
w / Mn), crystallinity, melting point, heat of fusion, and density were measured. The results are shown in Table 1.

A two-component electrostatic toner was prepared in the same manner as in Example 1 except that PW-6 was used instead of PW-1, and the fixability of the fixed image, toner blocking resistance, and offset phenomenon were observed. , The image disturbance, and the contamination of the photoconductor / fixing roller were evaluated. The results are shown in Table 1.

(Comparative Example 3) Instead of PO-1, high molecular weight ethylene / ethyl acrylate copolymer (Mn: 155
00, ethyl acrylate content: 17.0 mol%, crystallinity: 15%, hereinafter referred to as "PO-5") at 435 ° C.
Ethylene / ethyl acrylate copolymer wax (hereinafter referred to as "PW-
7 ”), and its number average molecular weight (Mn), molecular weight distribution (Mw / Mn), crystallinity, melting point, heat of fusion,
And the density was measured. The results are shown in Table 1.

A two-component electrostatic toner was prepared in the same manner as in Example 1 except that PW-7 was used in place of PW-1, and the fixability of the fixed image, blocking resistance of the toner, and offset phenomenon were observed. , The image disturbance, and the contamination of the photoconductor / fixing roller were evaluated. The results are shown in Table 1.

[0062]

[Table 1]

[0063]

The heat-fixing type electrophotographic developer of the present invention comprises:
It has excellent releasability, especially releasability at low energy fixing, excellent blocking resistance and fixing property, does not cause offset phenomenon, and does not contaminate carrier, photoconductor, heating roller, etc. It is suitable as the main component of the electrostatic toner.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeo Kigami 6-1-2 Waki, Waki-machi, Kuga-gun, Yamaguchi Mitsui Petrochemical Industry Co., Ltd.

Claims (2)

[Claims] 1. A copolymer of ethylene and at least one selected from unsaturated carboxylic acids and unsaturated carboxylic acid esters, wherein the content of ethylene units is 90 to 9.
9.9 mol% and number average molecular weight (Mn) is 300 to 8
A heat-fixing type electrophotographic developer containing the ethylene-based copolymer wax (A), the binder (B) and the colorant (C). 2. The method according to claim 1, wherein at least one selected from the unsaturated carboxylic acid and unsaturated carboxylic acid ester is at least one selected from acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester. Thermal fixing type electrophotographic developer.