JPH08234476A - Thermal fixing type electrophotographic developer - Google Patents

Abstract

(57) [Summary] [Objective] By using it as the main component of an electrostatic toner, it is possible to obtain an electrostatic toner that has excellent releasability during low-energy fixing as well as blocking resistance and fixing properties, and is able to prevent offset phenomena. Provided is a heat-fixing type electrophotographic developer that does not cause contamination and does not contaminate carriers, photoconductors, heating rolls and the like. [Structure] The main structural unit of the molecular skeleton is propylene or 1-butene, and the acid value is 0.1 to 6 mg-KOH /
g and number average molecular weight (Mn) of 1000 to 20000
A heat-fixing type electrophotographic developer containing the oxidation-modified polyolefin wax (A), a binder (B) and a colorant (C).

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 excellent in 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. The electrostatic toner is a charged fine powder in which a colorant such as carbon black or pigment is dispersed in 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 photoreceptor with electrostatic toner is transferred to paper, and an image obtained by directly developing on a paper on which a photosensitive layer is formed remains as it is. It is fixed by heat and 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.

Particularly, in recent years, the range of use of electrophotography has expanded, and the need for fixing under low energy has been increasing. That is, with the advance into household appliances and small appliances, it is required to reduce the power consumption of the heating roller portion, and also the demand for high-speed fixing property as a terminal for high-speed appliances such as computers. However, when fixing an image by bringing a heating body such as a heating roller into contact with the toner, when a conventional electrostatic toner is used, a part of the toner adheres to the heating body and is transferred to a 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 film is deteriorated, and at the same time, the offset phenomenon is likely to occur. Also, when copying at high speed, if the heating element is heated to a high temperature in order to increase the fixing effect and fixing speed,
There is a problem that this tends to cause the offset phenomenon. Therefore, for example, the roller surface is impregnated with silicone oil, or the silicone oil is supplied to the roller surface to eliminate the offset phenomenon. However, in this case, on the contrary, there may occur a problem that the roll becomes dirty.

On the other hand, various thermoplastic resins are used as the binder which is the main material of the electrostatic toner. In particular, a low molecular weight styrene / (meth) acrylic acid ester copolymer has good chargeability, good fixability because it has an appropriate softening point (around 100 ° C), easy cleaning of the photoconductor and less contamination It has features such as low hygroscopicity, good compatibility with carbon black as a coloring agent, and easy pulverization.
However, the conventional electrostatic toner using a low molecular weight styrene / (meth) acrylic acid ester copolymer or the like also has a problem that an offset phenomenon is likely to occur in fixing on a low temperature roll or high speed copying.

In order to solve such a problem, it has been proposed to add a polyolefin wax as a release agent to the electrostatic toner. (Japanese Patent Publication Nos. 52-3304, 52-3305, 57-52574, 58-58664, and 58-59455).

[0007]

However, the above-mentioned Japanese Patent Publication No. 5
Even when the technique described in Japanese Unexamined Patent Publication No. 2-3304 is applied, it is not possible to withstand the severe conditions of low energy fixing in recent years and sufficiently prevent the offset phenomenon. Further, the above-mentioned conventional technique may cause a problem different from the offset phenomenon. For example, a toner to which a polyolefin wax has been added may have a low blocking resistance, may cause blocking in the toner cartridge, and toner may not be supplied from the toner cartridge onto the photoreceptor. In addition, a phenomenon in which the low crystalline substance contained in the polyolefin wax adheres to the surface of the carrier, the photoconductor, the heating roller, etc., so-called filming phenomenon occurs, and an electrostatic latent image is formed on the photoconductor, toner It may adversely affect the charging and the resulting image may be significantly disturbed.

Therefore, an object of the present invention is to obtain an electrostatic toner which is used as a main component of an electrostatic toner and which is excellent in releasability at the time of low-energy fixing, and is also excellent in blocking resistance and fixing property. It is an object of the present invention to provide a heat-fixing type electrophotographic developer that does not cause a phenomenon and does not contaminate a carrier, a photoconductor, a heating roll 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 polyolefin to be added to an electrostatic toner, an oxidation-modified olefin polymer having a specific acid value and molecular weight is used. It was found that the above problems can be solved by using coalescing,
The present invention has been reached.

That is, in the present invention, the main structural unit of the molecular skeleton is propylene or 1-butene, the acid value is 0.1 to 6 mg-KOH / g, and the number average molecular weight (M
Oxidation-modified polyolefin wax (A), binder (B) and colorant (C) having n) of 1000 to 20000
The present invention provides a heat-fixing type electrophotographic developer including:

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 oxidation-modified polyolefin wax used as the component (A) of the developer of the present invention is obtained by oxidizing and modifying an olefin polymer, and the main structural unit of its molecular skeleton is propylene or 1- It is derived from butene. Here, the term "mainly" means that the content of the olefin having 2 to 4 carbon atoms in the molecular skeleton is 50 mol% or more, preferably 60 mol% or more.
As the olefin polymer, a polymer or copolymer of one or more olefins, or one or more olefins and olefins such as dienes and styrene monomers can be copolymerized. Examples thereof include copolymers with monomers. This oxidation-modified polyolefin wax (A) is blended with a toner to obtain a heat-fixing type electrophotographic developer having good fixability, blocking resistance, offset resistance, and stain resistance to a fixing roller. Therefore, it is preferable. Among these oxidation-modified polyolefin waxes, those in which the main structural unit of the molecular skeleton is propylene, particularly those containing 90 mol% or more of propylene units are particularly preferable.

The oxidation-modified polyolefin wax (A) has a functional group containing oxygen such as a carbonyl group, a carboxyl group and a hydroxy group in the molecule by oxidizing the olefin polymer. .

The oxidation-modified polyolefin wax (A) has an acid value of 0.1 to 6 mg-KOH / g, preferably 0.3 to 6 mg-KOH / g, and more preferably 0.5 to 5 mg. -KOH / g.
In the present invention, the acid value is measured according to JISK5902. Further, this oxidation-modified polyolefin wax (A) has a number average molecular weight (Mn) of 100.
0 to 20000, preferably 1000 to 1
It is 5,000. In the present invention, the number average molecular weight (Mn) is a value determined by gel permeation chromatography (GPC). The calculation of this molecular weight is performed using a calibration curve prepared using monodisperse polystyrene. The molecular weight distribution (Mw / Mn) of this oxidation-modified polyolefin wax (A) is usually
It is about 2 to 5.

The oxidation-modified polyolefin wax (A) usually has a softening point of 70 to 150 ° C, preferably 80 to 145 ° C. In the present invention, the softening point is measured according to JIS K2207. Further, the oxidation-modified polyolefin wax (A) usually has a crystallinity of 30 to
It is 70%. In the present invention, the crystallinity is a value measured by an X-ray diffraction method.

The oxidation-modified polyolefin wax (A) usually has a melting point of 60 to 140 ° C. and a heat of fusion of 5 to 25 cal / g. Here, the melting point and the heat of fusion are values obtained by a differential scanning calorimeter (DSC).

The density of the oxidation-modified polyolefin wax (A) is usually 0.89 to 0.92 g / cm.
It is about ³ . In the present invention, the density is JIS K7.
112, and is measured by the density gradient tube method.

In the present invention, these oxidation-modified polyolefin waxes (A) may be used alone or in combination of two or more.

The oxidation-modified polyolefin wax (A) can be produced, for example, by the following method. [1] (1) Homopolymerization of propylene or 1-butene, or copolymerization of the propylene or 1-butene with the above-mentioned other olefins in the medium- and low-pressure method using a transition metal catalyst such as Ziegler catalyst A method in which a polyolefin wax directly obtained or (2) a polyolefin wax having the same composition as the polyolefin wax of (1) is thermally degraded to be oxidized with, for example, air or oxygen under melting [ 2] A method of oxidizing and degrading the above-mentioned polyolefin wax or a high-molecular-weight polyolefin having the same composition as that of the polyolefin wax and polymerized by the medium- and low-pressure method or the like with air or oxygen while maintaining a solid state at a temperature below its melting point. In the present invention, as the oxidation-modified polyolefin wax (A), the above [1 When an oxidation-modified polyolefin wax obtained by oxidizing a polyolefin wax obtained by direct polymerization by the medium-low pressure method or the like in the method (1) is used, the raw material polyolefin wax has an intrinsic viscosity [η] measured in decalin at 135 ° C. ] Is preferably in the range of 0.05 to 0.7 dl / g. Further, as in the above method [1]-(2), when an oxidation-modified polyolefin wax obtained by oxidizing a polyolefin wax obtained by thermally degrading a high molecular weight polyolefin is used, a polyolefin wax as a raw material is used. Has an intrinsic viscosity [η] of 0.05 to 0.7 dl
Those in the range of / g are preferable. In the above method [2], the polyolefin wax or the high molecular weight polyolefin used as a raw material preferably has an intrinsic viscosity [η] of 0.5 dl / g or more.

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

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. This styrene polymer may be composed of one or more styrene monomers, or one or more styrene monomers and one or more other vinyls. It may be composed of a system monomer. In addition, this styrene-based polymer,
The styrene content is preferably 25% by weight or more.

In the present invention, when a styrene polymer is used as the binder (B), those having a number average molecular weight (Mn) of 2000 or more are preferable among the styrene polymers, and particularly, the number average molecular weight ( Mn) is 3000 to 30
000 is preferable.

The colorant which is the component (C) of the developing material of the present invention may be any one as long as it is blended with this type of developing material, and is not particularly limited. For example, carbon black, phthalocyanine blue, aniline blue, alcohol oil blue, chrome yellow, ultramarine blue, quinoline yellow, lamp black, rose bengal, diazo yellow, rhodamine B rake, carmine 6
Examples thereof include pigments and dyes such as B and quinacridone derivatives, and these may be used alone or in combination of two or more.

As the colorant (C), for the purpose of complementary color and charge control, azine nigrosine, indulin,
Oil-soluble dyes such as azo dyes, anthraquinone dyes, triphenylmethane dyes, xanthene dyes, and phthalocyanine dyes may be added.

In the developer of the present invention, the oxidation-modified polyolefin wax (A), the binder (B) and the colorant (C) are usually mixed in such a proportion that the oxidation-modified polyolefin wax (A) / the binder ( The ratio of B) / colorant (C) is
The weight ratio is about 1 to 20/100/1 to 20, preferably about 1 to 10/100/1 to 10.

In addition to the oxidation-modified polyolefin wax (A), the binder (B) and the colorant (C), the developer of the present invention contains other components as long as the effects of the present invention are not impaired. You may. For example, other release agents, charge control materials, plasticizers, etc. may be appropriately mixed.

The developer of the present invention is a two-component electrostatic toner,
It can be used as a main component of any electrostatic toner such as a one-component electrostatic toner. When the developer of the present invention is used as the main component of the two-component electrostatic toner, the two-component electrostatic toner contains the oxidation-modified polyolefin wax (A), the binder (B), the colorant (C), And other components to be blended as needed are mixed by a known method using a ball mill, an attritor, etc., and then kneaded by using a heating two-roll, a heating kneader, an extruder, etc., 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 is
It may be a known one and is not particularly limited. For example, particle size 2
Examples include silica sand, glass beads, iron balls, and magnetic material powders of iron, nickel, cobalt, and the like having a particle size of 0 to 700 μm.

The content of the oxidation-modified polyolefin wax (A) in this two-component electrostatic toner is 1 to 100 parts by weight of the thermoplastic resin including the binder (B).
The amount is 20 parts by weight, preferably 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 is prepared by using the oxidation-modified polyolefin wax (A) and the binder (B).
And the colorant (C), other additives optionally added, other thermoplastic resin and magnetic material powder, are processed and prepared in the same manner as in the preparation of the two-component electrostatic toner. be able to.

The mixing amount of the oxidation-modified polyolefin wax (A) in this one-component electrostatic toner is 1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the binder (B). It is a ratio.

As the magnetic material powder to be blended in the one-component electrostatic toner, a magnetite fine powder having a particle size of 1 μm or less is usually used, and metals such as cobalt, iron and nickel, alloys thereof, Powders such as oxides, ferrite and mixtures thereof can also be used. The mixing 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, the image does not bleed, and the softening point is low. Since it is kept in an appropriate range, fixing can be suitably carried out, a required charge value can be obtained, and scattering is also difficult. Therefore, the total amount of the binder (B) and the magnetic material powder is usually 100 parts by weight. On the other hand, magnetic material powder 40-1
The amount is 20 parts by weight. A known charge control agent may be added to the two-component electrostatic toner or the one-component electrostatic toner, if necessary.

Further, the oxidation-modified polyolefin wax (A) of the present invention can be easily made into a fine particle water dispersion by itself or by adding an emulsification aid such as a surfactant. It is also suitable as one component of the polymerized toner.

[0033]

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 following examples and comparative examples, the acid value, number average molecular weight (Mn) of the oxidation-modified polyolefin wax,
Measurement of softening point, crystallinity, melting point, and heat of fusion, and fixing property in toner evaluation, blocking resistance,
The offset phenomenon, the image disturbance, and the stain resistance of the photoconductor and the heating roller were evaluated according to the following methods.

Acid value: Measured according to JIS K5902.

Number average molecular weight (Mn), molecular weight distribution (Mw
/ Mn) Using o-dichlorobenzene as a solvent, a concentration of 0.1
A weight percent oxidation modified polyolefin wax sample 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 average molecular weight and the molecular weight distribution are calculated by a calibration curve prepared in advance using a monodisperse polystyrene standard sample.
The number average molecular weight (Mn) and the molecular weight distribution (Mw / Mn) were calculated in terms of polystyrene.

Softening point Measured in accordance with JIS K2207.

Crystallinity The oxidation-modified polyolefin wax was press-molded at 180 ° C. for 10 minutes at 2 kg / cm ² , and then cooled to prepare a sheet-like sample having a thickness of 1 mm. This sheet-shaped sample was placed on an X-ray diffractometer (Rigaku Denki Co., Ltd., Rotaflex Ru300, Cu target), and a tube voltage of 60 k was applied.
X-ray diffraction was measured by a transmission method at V and a tube current of 300 mA.
The drawing of the X-ray diffraction chart and the calculation of the crystallinity were performed according to the Natta method.

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

Fixability of Fixed Image Using the obtained two-component electrostatic toner, a test image is copied and developed on a selenium photoreceptor by electrophotography. The obtained image was transferred onto a transfer paper, and a fixing roller whose surface was formed of polytetrafluoroethylene (manufactured by DuPont) and a surface of silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd., KE-1)
The image was fixed by adjusting the temperature of the fixing roller to 200 ° C. using a pressure roller formed by 300 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 manufactured by Macbeth. The measurement was performed, and the fixability of the fixed image was determined according to the following formula. Fixability (%) = {(image density after rubbing) / (image density before rubbing)} × 100

Blocking Resistance of Toner 100 g of the obtained two-component electrostatic toner is charged to a capacity of 500 m.
1 polyethylene container, shake for 30 minutes,
The mixture was allowed to stand at 60 ° C. for 50 hours, returned to room temperature, examined for blocking, and evaluated according to the following criteria. ◎ 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, Distortion of Image, Contamination of Photosensitive Member / Fixing Roller The obtained two-component electrostatic toner is used to copy and develop a test image on a selenium photosensitive member 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.,
The copying step of fixing the image using a pressure roller formed of KE-1300 RTV) was repeated. Fifty
After repeating the copying process 00 times, the presence or absence of an offset phenomenon, the presence or absence of image disturbance, and the contamination of the surface of the photoconductor / fixing roller were visually inspected and evaluated according to the following criteria.

Offset Phenomenon, Image Distortion: There was no offset phenomenon or image disturbance. Fairly slight offset phenomenon or image sagging 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 Oxidation-Modified Polyolefin Wax A high molecular weight propylene obtained by copolymerizing propylene, ethylene and 1-butene in the presence of a solid titanium catalyst having titanium supported on magnesium chloride. Ethylene / 1-butene copolymer powder (propylene content: 94 mol%, ethylene content: 5 mol%, 1-butene content: 1 mol%,
[Η]: 2.0 dl / g) was supplied to a twin-screw extruder (screw diameter: 30 mmφ), and the screw rotation speed was 25 rp.
While extruding and kneading at m, heat and degrade at 400 ℃,
[Η]: 0.18 dl / g propylene / ethylene / 1
A butene copolymer wax was produced. 1 kg of the obtained propylene / ethylene / 1-butene copolymer wax was melted in a glass reactor having an internal volume of 2 liters, while stirring at 170 ° C., while blowing oxygen at 4 liters / minute and nitrogen at 2 liters / minute. Oxidation-modified propylene after oxidation for 3.0 hours
An ethylene / 1-butene copolymer wax was produced. Acid value, number average molecular weight (Mn), softening point, crystallinity, melting point, and heat of fusion of the obtained oxidation-modified propylene / ethylene / 1-butene copolymer wax (hereinafter abbreviated as "W-1") Was measured. The results are shown in Table 1.

[Preparation of Toner] Styrene / n-butylmethacrylate copolymer (manufactured by Sanyo Chemical Industry Co., Ltd., Hymer SEM-73F) 85 parts by weight, W-14 4 parts by weight, carbon black (Sanyo Chemical Industry Co., Ltd. ), And 9 parts by weight of Diamond Black SH) and 2 parts by weight of a metal-containing dye (manufactured by BASF, Zabon Fast Black B) were supplied to a ball mill and mixed for 24 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. The two-component electrostatic toner was evaluated for fixability of a fixed image, toner blocking resistance, offset phenomenon, image disturbance, and contamination of the surface of the photoconductor / heating roller. Table 2 shows the results.

Example 2 Production of Oxidation-Modified Polyolefin Wax A high-molecular-weight propylene / ethylene copolymer obtained by copolymerizing propylene and ethylene in the presence of a solid titanium catalyst having titanium supported on magnesium chloride. Powder (Propylene content 9
7 mol%, [η]: 1.7 dl / g) was supplied to a twin-screw extruder (screw diameter 30 mmφ), and heat-degraded at 400 ° C. while extruding at a screw rotation speed of 25 rpm, and [η]: 0 A 17 dl / g propylene / ethylene copolymer wax was prepared. 1 kg of the obtained propylene / ethylene copolymer wax was melted in a glass reactor having an internal volume of 2 l, and 4 l of oxygen was added under stirring at 170 ° C.
/ Min, nitrogen was blown at a rate of 2 l / min for oxidation for 1.5 hours to produce an oxidation-modified propylene / ethylene copolymer wax. Acid value of the obtained oxidation-modified propylene / ethylene copolymer wax (hereinafter abbreviated as "W-2"),
The number average molecular weight (Mn), softening point, crystallinity, melting point, and heat of fusion were measured. The results are shown in Table 1.

[Toner Preparation] W-2 instead of W-1
A two-component electrostatic toner was prepared in the same manner as in Example 1 except that was used, and the fixability of the fixed image, toner blocking resistance, offset phenomenon, image disturbance, and The surface stainability was evaluated. Table 2 shows the results.

(Example 3) [Production of Oxidation-Modified Polyolefin Wax] Except for changing the time for oxidative modification to 3 hours, the procedure of Example 2 was repeated.
An oxidation-modified polypropylene wax (hereinafter abbreviated as "W-3") was produced, and its acid value, number average molecular weight (Mn), softening point, crystallinity, melting point, and heat of fusion were measured. The results are shown in Table 1.

[Preparation of Toner] W-3 instead of W-1
A two-component electrostatic toner was prepared in the same manner as in Example 1 except that was used, and the fixability of the fixed image, toner blocking resistance, offset phenomenon, image disturbance, and The surface stainability was evaluated. Table 2 shows the results.

Example 4 Production of Oxidation-Modified Polyolefin Wax Oxidation-modified polypropylene wax (hereinafter referred to as "W-4") was carried out in the same manner as in Example 2 except that the time for oxidative modification was 10 hours.
Abbreviated), its acid value, number average molecular weight (Mn),
The softening point, crystallinity, melting point, and heat of fusion were measured.
The results are shown in Table 1.

Other than using W-4 instead of W-1,
A two-component electrostatic toner was prepared in the same manner as in Example 1, and the fixability of the fixed image, the blocking resistance of the toner, the offset phenomenon, the disorder of the image, and the contamination of the surface of the photoconductor / heating roller were evaluated. did. Table 2 shows the results.

Example 5 Production of Oxidation Modified Polyolefin Wax Butene-1
Is a high molecular weight polybutene-copolymerized in the presence of a solid titanium catalyst supporting titanium on magnesium chloride.
1 ([η]: 1.1 dl / g) was supplied to a twin-screw extruder (screw diameter 30 mmφ), and the screw rotation speed was 25 r
While extruding and kneading at pm, heat-degrade at 375 ° C,
[Η]: 0.22 dl / g of polybutene-1 wax was produced. 1 kg of the obtained polybutene-1 wax was dissolved in a glass reactor having an internal volume of 2 l, and oxidation was carried out at 170 ° C. for 4.5 hours while stirring while blowing oxygen at 4 l / min and nitrogen at 2 l / min. And oxidation-modified polybutene-1
A wax (hereinafter abbreviated as "W-5") is produced, and its acid value, number average molecular weight (Mn), softening point, crystallinity, melting point,
And the heat of fusion was measured. The results are shown in Table 1.

[Preparation of Toner] W-5 instead of W-1
A two-component electrostatic toner was prepared in the same manner as in Example 1 except that was used, and the fixability of the fixed image, toner blocking resistance, offset phenomenon, image disturbance, and The surface stainability was evaluated. Table 2 shows the results.

Comparative Example 1 Example 2 was used instead of W-1.
Polypropylene wax before oxidation modification obtained in ((hereinafter,
A two-component electrostatic toner was prepared in the same manner as in Example 1 except that "W-6" was used), and the fixability of the fixed image, toner blocking resistance, offset phenomenon, and image disturbance , And the surface contamination of the photoconductor / heating roller were evaluated. Table 2 shows the results.

Comparative Example 2 [Production of Oxidation-Modified Polyolefin Wax] Oxidation modification of Example 2 was carried out in the same manner as in Example 2 except that the reaction temperature was 180 ° C. and the reaction time was 12 hours. A modified polypropylene wax (hereinafter abbreviated as "W-7") was produced, and its acid value, number average molecular weight (Mn), softening point, crystallinity, melting point, and heat of fusion were measured. The results are shown in Table 1.

Other than using W-7 instead of W-1,
A two-component electrostatic toner was prepared in the same manner as in Example 1, and the fixability of the fixed image, the blocking resistance of the toner, the offset phenomenon, the disorder of the image, and the contamination of the surface of the photoconductor / heating roller were evaluated. did. Table 2 shows the results.

Comparative Example 3 [Production of Oxidation Modified Polyolefin Wax] The same high molecular weight propylene / ethylene copolymer powder as used in Example 2 (propylene content 97 mol%, [η]: 1.7)
dl / g) 200g, internal volume 1l with wire mesh attached to the bottom
Was charged into the stainless steel reactor described above, air was blown at 5 l / min, and oxidative degradation was performed at 132 ° C. for 45 minutes while gently stirring to produce an oxidation-modified polypropylene wax (hereinafter abbreviated as “W-8”). , Its acid value, number average molecular weight (Mn), softening point, crystallinity, melting point, and heat of fusion were measured. The results are shown in Table 1.

Other than using W-8 instead of W-1,
A two-component electrostatic toner was prepared in the same manner as in Example 1, and the fixability of the fixed image, the blocking resistance of the toner, the offset phenomenon, the disorder of the image, and the contamination of the surface of the photoconductor / heating roller were evaluated. did. Table 2 shows the results.

[0060]

[0061]

[0062]

The heat-fixing type electrophotographic developer of the present invention comprises:
It is suitable as a main component of electrostatic toner because it has excellent releasability during heat fixing and blocking resistance, has no offset phenomenon, and does not contaminate carriers, photoconductors, heating rollers and the like. .

Front page continued (72) Inventor Seiji Ota 6-12 Waki, Waki-cho, Kuga-gun, Yamaguchi Mitsui Petrochemical Co., Ltd.

Claims (4)

[Claims] 1. The main structural unit of the molecular skeleton is propylene or 1-butene, and the acid value is 0.1 to 6 mg-KOH.
/ G and number average molecular weight (Mn) is 1000 to 2000
A heat-fixing type electrophotographic developer containing 0, an oxidation-modified polyolefin wax (A), a binder (B) and a colorant (C). 2. The heat-fixing type electrophotographic developer according to claim 1, wherein the oxidation-modified polyolefin wax (A) has propylene as a main constituent unit of a molecular skeleton. 3. The heat-fixing electrophotography according to claim 1, wherein the oxidation-modified polyolefin wax (A) is polypropylene oxide containing 90 mol% or more of propylene units and has a softening point of 70 to 150 ° C. Developer material. 4. The heat fixing according to claim 1, wherein the oxidation-modified polyolefin wax (A) is polypropylene oxide containing 90 mol% or more of propylene units and has a softening point of 80 to 145 ° C. Type electrophotographic developer.