JP2597452B2 - Electrophotographic toner - Google Patents

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 fixing a hot roll.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic toner for fixing a hot roll has been widely used, which comprises a binder resin, a wax, a colorant, a charge control agent and the like. The composition of the toner most commonly used conventionally is shown below.

Binder resin (however, may contain 2-3% by weight of wax) 45 to 96% by weight Colorant, magnetic substance, etc. 5 to 50% by weight Charge control agent 1 to 5% by weight

[0004] As can be seen from the above composition, the binder resin accounts for the majority of the toner. Therefore, the physical properties of the binder resin
It greatly affects the physical properties of the toner. That is, by controlling the physical properties of the binder resin, the physical properties of the toner can be controlled. Conventionally, as the resin that makes up most of the binder resin,
Styrene-acrylate copolymers, polyester resins, epoxy resins, olefin resins, and the like are used.

[0005] The binder resin often contains wax. This wax is contained to prevent offset and to improve the dispersibility of the colorant. The most commonly used waxes are synthetic hydrocarbon waxes and waxes refined from petroleum. Examples include polypropylene, polyethylene , paraffin, microcrystalline and the like. Since the melting start temperature of the wax and the melting start temperature of the toner have additive properties, the lower the melting start temperature of the wax, the lower the fixing temperature of the toner. The melting start temperature of general synthetic hydrocarbon or petroleum wax is about 100
C. to 150C.

As for the colorant, fine particles of carbon black are used for ordinary black-and-white copying. Alternatively, nigrosine or spirit black may be used for charge control.

[0007] The charge control agent is contained for controlling the charge of the toner, and can be roughly classified into those for the (+) toner and those for the (-) toner. For (+) toner, a dye having an electron donating property is mainly used. For example, azine compounds, naphthenic acid, quaternary ammonium salts,
Examples thereof include alkylamides. For (-) toner, an organic complex having an electron donating property is preferable, and examples thereof include an azo metal complex.

[0008]

Recently, the problem of global environmental protection has been called out, and the safety of waste has become a problem. In particular, Italy has imposed a tax of 100 lira per non-degradable shopping bag since 1987 to solve the plastic waste problem. Further, since 1991, a law has been promulgated that shopping bags and bottles must be manufactured from biodegradable materials. Other European countries and US states are considering legislation on plastic use restrictions and conversion to degradable polymers.

Under these circumstances, biodegradable resins have been actively developed, and there are some practical examples of medical materials. In the field of agriculture, multi-files, sustained-release pesticides, fertilizers, horticultural materials and the like have been put to practical use. In the leisure field, fishing lines, fishing gear, golf tees and the like can be exemplified. Furthermore, it has been put to practical use in containers for daily necessities such as daily necessities packaging materials.

Naturally, when discarding printed matter,
Also, there has been a problem in the treatment of waste toner generated in the electrophotographic process, and a toner having no problem in disposal is demanded. Along with environmental protection, there is a need for a toner capable of reducing the power consumption of a copying machine from the viewpoint of energy protection.

That is, in view of the recent background described above, the toner for electrophotography does not generate toxic gas when burned, and when it is landfilled or dissipated into the natural environment, it is finally decomposed and accumulated. Therefore, when separated and collected, composting and monomerization are easy and the power consumption of the copier can be reduced. However, none of the toners obtained by the above-mentioned prior art satisfy these quality requirements at the same time.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is not only capable of being biodegradable and not adversely affecting the natural environment, and satisfying various characteristics as a toner. An object of the present invention is to provide an electrophotographic toner that can reduce power consumption.

[0013]

In the electrophotographic toner of the present invention, the binder resin contains at least a vegetable wax and a biodegradable resin, and the vegetable wax is contained in the binder resin. The above object was achieved by adding the compound in an amount of from 50% by weight to 50% by weight. Further, the toner for electrophotography of the present invention has a melting start temperature of 80 as the above-mentioned vegetable wax.
The object has been achieved by using a vegetable wax having a temperature of not more than ℃.

It is easily conceivable that a biodegradable resin may be used for the binder resin, which is the main component of the toner, in order to satisfy the above-mentioned characteristics required for the toner.

Therefore, the present inventors first studied on biodegradable resins. As factors affecting biodegradability, those having an aliphatic ester bond, a glucoside bond, an ether bond, and a peptide bond in the main chain are susceptible to microbial degradation, and therefore, resins that can be used as biodegradable resins are shown below. I chose the street and roughly divided it into

Microorganism-produced polyester Examples of this include β-hydroxybutyric acid and β-hydroxyvaleric acid (manufactured by ICI). These polyesters, starting from agricultural products,
Hydrogen bacteria (Alcaligenes eutrophs), a kind of soil fungus
By sugar fermentation.

Natural polymer materials derived from plants and animals Examples of the polymer materials include the following polymer materials.・ Thermoplastic starch ・ Cellulose / chitosan polymer material ・ Pullulan / chitosan polymer material ・ Arabinogalactan

Biodegradable synthetic polymer material This polymer material can be further roughly classified into 1) to 4). 1) Low-molecular-weight aliphatic polyesters and copolyesters Examples thereof include polyε-caprolactone, polyε-methyl-δ-valerolactone, and polyethylene adipate. These polymeric materials are
It can be synthesized by the following method.・ Dehydration condensation reaction between diol and dicarboxylic acid ・ High temperature non-catalytic polymerization of cyclic ester (lactone) ・ Polymerization in the presence of low molecular weight alkylene diglycol ・ Ring-opening polymerization using enzyme

2) High-Molecular-Weight Aliphatic Polyesters and Copolyesters Examples thereof include polyglycolide, polylactides, copoly (glycolide / lactide), polyε-caprolactone and the like. These polymer materials are obtained by ring-opening polymerization of a cyclic diester (glycolide, lactide) or a lactone using an organometallic catalyst (for example, an organic catalyst containing aluminum, zinc, tin or the like).

3) Copolyester ether This polymer material can be synthesized by the following method.・ Ring-opening polymerization of cyclic ester ether ・ Ring-opening polymerization of cyclic ether and cyclic ester ・ Ring-opening polymerization of cyclic ester by polyether oligomer ・ Ring-opening polymerization between telechelic oligomers

4) Copolyesteramide This polymer material can be synthesized by the following method. -Ring-opening polymerization and copolymerization of cyclic ester amide-Copolymerization of cyclic ester and cyclic amide-Condensation polymerization of amino alcohol and dicane rubonic acid, or polyester oligomer having a carboxyl group at both ends and diamine-Polyester, Interpolymer reaction with nylon

A mixture of the above-mentioned polymer materials or a composite compound

After selecting and broadly dividing the preferred resin as the biodegradable resin for the electrophotographic toner of the present invention as described above,
The resin in the binder resin contained in the conventional toner was replaced with these biodegradable resins to form a toner. The obtained toner had poor pulverizability, could not obtain a desired particle size, and could not be used as a toner.
Furthermore, the fixing property was poor and it could not withstand practical use.

Therefore, the present inventors have studied to improve the fixing property and the pulverization property of the toner using the biodegradable resin. As a result, they have found that the pulverizability can be improved by replacing the synthetic hydrocarbon or petroleum wax conventionally contained in the binder resin with a vegetable wax.

Next, an experiment was conducted to determine a preferable amount of the vegetable wax contained in the binder resin. As a result, it was found that a toner containing a vegetable wax in a range of 5% by weight or more and 50% by weight or less in a binder resin can be put to practical use. When the content of the vegetable wax was less than 5% by weight, pulverizability for pulverization could not be obtained. On the other hand, if it is more than 50% by weight, there is a problem in compatibility between the wax and the biodegradable resin, and the two are mixed unevenly. As a result, the charging characteristics of the toner deteriorated, and problems occurred in storage stability.

The lower the melting start temperature of the wax used, the more preferable. This is because the lower the wax melting start temperature, the lower the toner fixing temperature. Specifically, a vegetable wax having a melting start temperature of 80 ° C. or lower, which is lower than the conventional melting start temperature (about 100 ° C.), is preferable. However, if the melting start temperature is lowered unnecessarily, for example, if the temperature is lower than room temperature, the wax will always be in a molten state, which is not preferable for storage stability.
Therefore, a temperature higher than room temperature, for example, 40 ° C. or higher is preferable. Therefore, the melting start temperature of the vegetable wax used in the toner for electrophotography of the present invention is set to a temperature that can lower the melting start temperature of the toner and is preferable for storage stability, that is, 40 ° C. or more and 80 ° C. or less. Is preferred.

Examples of the vegetable wax having such a melting start temperature include rice wax, hydrogenated jojoba oil wax, wood wax, candelilla wax, carnauba wax and the like. These natural plant-based wax, if the melting start temperature because it contains impurities is high and 80 ° C. or more, to 80 ° C. or less by the degree to adjust <br/> purification Can also.

Further, it has been found by experiments that when the wax ester component of the vegetable wax is 93% by weight or more, the melting start temperature becomes 80 ° C. or less.

The electrophotographic toner of the present invention comprises a colorant, a charge control agent, and other additives as required, in addition to the binder resin and the vegetable wax.

As the coloring agent, a conventionally used material can be used. For example, carbon black, monoazo red pigment, disazo yellow pigment, quinacridone magenta pigment, anthraquinone dye and the like can be exemplified.

As the charge control agent, a charge control agent conventionally used can be used. Examples thereof include nigrosine dyes, quaternary ammonium salts, and monoazo metal complex salt dyes.

Other additives that may be added as needed include fluidizers. As the fluidizing agent, resin fine particles, hydrophobic silica, colloidal silica and the like can be exemplified similarly to the conventional materials.

Although the content of the coloring agent, charge controlling agent and other optional additives in the toner is very small, those having biodegradability in consideration of disposal are considered. It is preferred to use.

The present inventors conducted experiments on the assumption that animal waxes could be used since vegetable waxes are preferred. Toners using animal waxes have poor fixability to paper and have been difficult to put into practical use.

The toner for electrophotography of the present invention comprising the above-mentioned materials is prepared by mixing the above-mentioned raw materials into a desired compound, as in the prior art.
After melt-kneading, it can be obtained by cooling, solidifying and pulverizing and classifying.

The melting start temperature used in the present invention means the temperature at which the plunger starts to fall under the following conditions. Measuring machine: High flow tester CF manufactured by Shimadzu Corporation
-500 Measuring condition: Plunger 1 cm ² Die diameter 1 mm Die length 1 mm Load 20 KgF Preheating temperature 50-80 ° C Preheating time 300 sec Heating rate 6 ° C / min

[0037]

In the electrophotographic toner of the present invention, the binder resin contains at least a vegetable wax and a biodegradable resin, and the vegetable wax is contained in the binder resin in an amount of 5% by weight or more.
0% by weight or less is added. Since the binder resin constituting most of the toner is biodegradable, the electrophotographic toner of the present invention is biodegradable. Further, since the vegetable wax is added in the binder resin in an amount of 5% by weight or more and 50% by weight or less, a toner having excellent crushability and a desired particle size can be obtained.

[0038]

The present invention will be described below in more detail with reference to examples. In the examples, “parts” means “parts by weight”.

Example 1 First, toner particles having the following composition were obtained.・ Binder resin ・ Hydroxyvaleric acid / hydroxybutyric acid copolymer 100 parts (monomer composition: 20:80) ・ Rice wax 6 parts ・ Carbon black 6.5 parts (Mitsubishi Chemical Industries, trade name: MA-100)・ 2 parts of charge control agent (Hoechst, product name: NX VP434)

A resin prepared by mixing a hydroxyvaleric acid / hydroxybutyric acid copolymer and rice wax was used as a binder resin. The ratio of the rice wax contained in the binder resin was 5.66% by weight. The melting start temperature of rice wax was 71.1 ° C.

The raw materials having the above composition are mixed by a super mixer, melt-kneaded, pulverized and classified to have an average particle diameter of 11
Thus, negatively-chargeable toner particles having a particle diameter of μm were obtained. In the pulverization and classification process, pulverization and classification could be performed without any problem.

Next, the obtained toner particles and 0.3 part of hydrophobic silica (trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) with respect to 100 parts of the toner particles are put into a Henschel mixer, and the mixture is agitated. Silica was attached to the toner particles to obtain an electrophotographic toner of this example.

Example 2 The same operation as in Example 1 was performed, except that the composition of the toner particles was changed as follows.・ Binder resin ・ Hydroxyvaleric acid / hydroxybutyric acid copolymer 100 parts (monomer composition: 20:80) ・ Rice wax 10 parts ・ Carbon black 6.5 parts (Mitsubishi Chemical Industry Co., Ltd., trade name: MA-100)・ 2 parts of charge control agent (Hoechst, product name: NX VP434)

The ratio of rice wax contained in the binder resin was 9.09% by weight. In the pulverization process, pulverization and classification could be performed without any problem.

Example 3 The same operation as in Example 1 was performed except that the composition of the toner particles was changed as follows.・ Binder resin ・ Hydroxyvaleric acid / hydroxybutyric acid copolymer 100 parts (monomer composition: 20:80) ・ Rice wax 15 parts ・ Carbon black 6.5 parts (Mitsubishi Kasei Kogyo Co., Ltd., trade name: MA-100)・ 2 parts of charge control agent (Hoechst, product name: NX VP434)

The ratio of the rice wax contained in the binder resin is 13.04% by weight. In the pulverization process, pulverization and classification could be performed without any problem.

Comparative Example 1 The same operation as in Example 1 was performed except that the composition of the toner particles was changed as follows (without using rice wax).・ Binder resin ・ Hydroxyvaleric acid / hydroxybutyric acid copolymer 100 parts (monomer composition: 20:80) ・ Carbon black 6.5 parts (Mitsubishi Chemical Industries, trade name: MA-100) ・ Charge control agent 2 Department (Hoechst, product name: NX VP434)

The ratio of the rice wax contained in the binder resin is 0.00% by weight. The toner having the above composition has poor pulverizability at the time of production, and has a problem in productivity.

Comparative Example 2 The same operation as in Example 1 was performed except that the composition of the toner particles was changed as follows.・ Binder resin ・ Hydroxyvaleric acid / hydroxybutyric acid copolymer 100 parts (monomer composition: 20:80) ・ Rice wax 5 parts ・ Carbon black 6.5 parts (Mitsubishi Kasei Kogyo Co., Ltd., trade name: MA-100)・ 2 parts of charge control agent (Hoechst, product name: NX VP434)

The ratio of the rice wax contained in the binder resin was 4.76% by weight.

(Comparative Example 3) Except that the composition of the toner particles was changed as follows (instead of mixing 6 parts of rice wax, 3 parts of polypropylene which is a synthetic hydrocarbon wax commonly used was mixed). The same operation as in Example 1 was performed.・ Binder resin ・ Hydroxyvaleric acid / hydroxybutyric acid copolymer 100 parts (monomer composition: 20:80) ・ Carbon black 6.5 parts (Mitsubishi Chemical Industries, trade name: MA-100) ・ Charge control agent 2 Part (Hoechst, product name: NX VP434)-Polypropylene 3 parts (Sanyo Chemical Industries, product name: Viscol 330P)

The ratio of the rice wax contained in the binder resin is 0.00% by weight.

Next, a copying machine (manufactured by Sharp Corporation, trade name:
SF9800) was filled with the toner for electrophotography obtained in Examples 1 to 3 and Comparative Examples 1 to 3, and copying was performed to examine the fixability of the obtained toner. As a result, the fixing properties of the toners obtained in Examples 1, 2, and 3 were good. However, the toner obtained in Comparative Example 1 did not fix at all. The paper developed with the toner obtained in Comparative Example 2 was in a state where the toner could be removed by rubbing the fixed image, and the fixability was very poor. The fixability of the toner obtained in Comparative Example 3 was not satisfactory.

Further, in order to examine the biodegradability, the obtained toner was melt-molded into a film having a thickness of about 50 μm.
It was left in the soil at 5 ° C. for 10 weeks. As a result, the shapes of the films made of the toners obtained in Examples 1, 2, and 3 almost disappeared. However, the shapes of the films made of the toners obtained in Comparative Examples 1, 2, and 3 remained as they were.

From these experimental results, it was found that the content of the vegetable wax contained in the binder resin, that is, the rice wax was preferably in a range of 5% by weight or more.

The electrophotographic toner of this embodiment contains rice wax as a binder resin and a hydroxyvaleric acid / hydroxybutyric acid copolymer. Since the binder resin, which is the main component of the toner, is biodegradable, the electrophotographic toner of this example did not adversely affect the natural environment. Furthermore, since the binder resin contained 5% by weight or more of rice wax, the toner could be pulverized to a desired particle size when pulverizing the toner. In addition, since a rice wax having a low melting start temperature of 71.1 ° C. was used as the vegetable wax, the melting start temperature of the binder resin could be lowered. Therefore, the toner for electrophotography of the present example was able to satisfy various characteristics as a toner, was low in fixing temperature, and was able to reduce power consumption of a copying machine in particular.

[0057]

As described above, in the electrophotographic toner according to the present invention, at least the binder resin contains a vegetable wax and a biodegradable resin. The binder resin occupying most of the toner is biodegradable. Therefore, the electrophotographic toner of the present invention is biodegradable and does not adversely affect the natural environment.

In the electrophotographic toner according to the present invention, at least the binder resin contains a vegetable wax and a biodegradable resin, and the vegetable wax is contained in the binder resin in an amount of 5% by weight to 50% by weight. Since it is added below, it has excellent pulverizability. Therefore, the electrophotographic toner of the present invention can have a desired particle size and can be put to practical use.

Since the toner for electrophotography according to the present invention contains a vegetable wax having a melting start temperature of 80 ° C. or lower, the melting start temperature of the toner is lower than that of the conventional toner. Therefore, if the electrophotographic toner of the present invention is used, the temperature of the fixing device of the copying machine can be maintained at a low temperature, so that the power consumption of the copying machine can be reduced.

Claims (2)

(57) [Claims] 1. A method in which at least the binder resin is a vegetable wax.
And a biodegradable resin, wherein the vegetable wax is added to the binder resin at a ratio of 5% by weight or more and 50% by weight or less , and a wax ester component in the vegetable wax.
Is not less than 93% by weight . 2. The melting start temperature of the vegetable wax is 8
2. The electrophotographic toner according to claim 1, wherein the temperature is 0 ° C. or lower.