JPS6134555A - Preparation of electrophotographic toner - Google Patents

Abstract

PURPOSE:To enhance humidity resistance of a toner and its electric resistivity under high humidity and to obtain a sharp image by polymerizing a monomer in an aq. medium contg. a cellulosic suspending agent in the presence of a pigment and treating the obtained polymer particles contg. the pigment with a cellulase. CONSTITUTION:At least one kind of monomer is polymerized in an aq. medium contg. a cellulisic suspending agent in the presence of the pigment, and the obtained polymer particles contg. the pigment are treated with a cellulase. The suspending agent is easily decomposed by such a treatment and the polymer can be cleaned of it to reduce an amt. of this agent to be left on the polymer. As a result, since the toner is good in humidity resistance, high in resistivity under high humidity, and sharp image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing an electrophotographic toner.

(Prior Art) Since the conventional method for producing electrophotographic toner using the so-called pulverization method involves complicated steps and consumes a large amount of energy, alternative production methods have been proposed. That is,
As a method to obtain toner directly without involving the grinding process,
This is a method in which pigments, dyes, etc. are added to monomers, and they are subjected to emulsion polymerization or suspension polymerization to form fine particles of resin containing pigments, etc., and the resulting fine particles are washed and dried (for example, 3 (S-1023, No. 1, Special Publication No. 1973-107)
No. 99, Special Publication No. 51-14895). This method has the advantage that the toner particles produced are almost spherical and have excellent fluidity, and the manufacturing process is simple and the cost is low.

However, in this method, monomers, monomer initiators, suspending agents, emulsifiers, molecular weight regulators, etc. added during polymerization remain in the pigment-containing polymer as they are.

In particular, the suspending agent lowers the electrical resistance value, making it impossible to obtain a toner of high quality that can be put to practical use. In particular, for negative-component toners, waxy substances with low electrical resistance are used
Since it is contained in a high proportion of 80% by weight, it synergistically lowers the electrical resistance value together with the remaining suspending agent. As a result, the amount of charge on the toner is low (the developed image is disturbed, making it impossible to obtain a good hard copy).

Further, the water-resistant suspending agent remaining in the toner promotes the hygroscopicity of the toner and significantly lowers the electrical resistance value of the toner in a high temperature environment, making it impossible to obtain a clear image.

Conventionally known methods for removing the suspending agent include washing the polymer with water, extracting the polymer with a poor bath medium, and the like. However, these methods not only require complicated operations and are economically disadvantageous, but also have the disadvantage that sufficient removal of the suspending agent is inhibited by the coexistence of pigments, making them almost ineffective. .

(Points to be Solved by the Invention) As a result of intensive research in order to solve the above-mentioned drawbacks, the present inventor has decomposed a polymer produced using a cellulose suspending agent in an aqueous medium in the presence of a pigment. We have discovered that by treating with an enzyme, the suspended TH agent can be easily decomposed and removed, and the resulting toner has less hygroscopicity (and the electrical resistance value is significantly improved), and we have arrived at the present invention. (Means for Solving the Problems) That is, the present invention provides a pigment-containing polymer obtained by polymerizing at least one monomer in an aqueous medium using a cellulose suspending agent in the presence of a pigment. The present invention provides a method for producing an electrophotographic toner, which comprises treating particles with a cellulolytic enzyme.

Although various monomers can be used in the present invention, vinyl monomers are particularly suitable. For example, styrene, vinyltoluene, α-methylstyrene, etc. (DX-based compounds, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methacryl Acrylic acid or methacrylic acid derivatives such as methyl acid, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylonitrile, acrylamide, ethylene, propylene, Ethylenically unsaturated monoolefins such as butylene, butadiene, 4) diolefins such as 7'lene and piperylene, vinyl chloride, vinylidene chloride, vinyl halides such as vinyl fluoride, vinyl acetate, vinyl propionate and other vinyl esters, vinyl methyl ether,
Examples include vinyl ethers such as vinyl ethyl ether, vinyl ketones such as vinyl methyl ketone and methyl isopluvenyl ketone, and nitrogen-containing vinyl compounds such as 2-vinylpyridine, 4-vinylpyridine, and N-vinylpyrrolidone. These monomers may be used alone or in combination and copolymerized. In addition to these early wrinkles, divinylbenzene, divinylnaphthalene and
Aromatic divinyl compounds such as derivatives of t-; diethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; divinyl compounds such as N,N-cyhinyl aniline and cyhinyl ether; and 6111! It is also possible to use crosslinking monomers such as compounds having a vinyl group of I1 or more, alone or in combination of two or more.

Examples of the cellulose used in the present invention include methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, hydroxybutylmethylcellulose, carboxymethylcellulose or its salts, and hydroxyethylcellulose. The amount of water-soluble protein used varies depending on polymerization conditions such as stirring and temperature, and the desired particle size of the polymer, but is usually 0.0 parts per 100 parts by weight of monomer.
The range is 0.01 to 5 parts by weight.

In addition, other known suspending agents or emulsifiers may be used together with the cellulose suspending agent at a weight ratio of 0 to 10 times the weight of the cellulose suspending agent. For example, polyvinyl alcohol,
Polyvinylpyrrolidone, polyacrylamide, polyacrylic el&t takeno salt, vinyl acetate-maleic acid copolymer, gelatin nato water-soluble protein, sodium dotenbenzene sulfonate, sodium lauryl sulfate,
Sodium laurate, sorbitan monodiurate, boroxyethene nonylphenyl ether, etc. can be used in combination.

The polymerization catalyst used in the present invention includes catalysts commonly used in suspension polymerization, such as α,α'-azobisisobutyronitrile, α,α'-azobis-2.4-
Dimethylvaleronitrile, 7'yl peroxide,! Examples include one or more combinations of 1,5.5-)limethylhexanoyl peroxide, t-pterperoxybiparate, acetylcyclohexylsulfonyl peroxide, and diloprobil baroxydicarbonate. It will be done.

Pigments used in the production of the toner of the present invention include, for example, titanium oxide, silicon dioxide, zinc oxide, carbon black, etc.; Magnetic powders such as iron-zinc, iron-nickel oxide, etc., and surface-treated pigments of these powders are used. From the viewpoint of dispersibility, pigments whose surfaces have been subjected to lipophilic treatment are preferred. The amount used is 1 to 400 parts by weight per 100 parts by weight of monomer.

In addition, in order to control the charge of the toner, optional dyes such as nigrosine base, aniline back, calco oil blue, chrome yellow, ultramarine blue, orient oil red, phthalocyanine blue, malachite green off-salate, and azo type may be used. Metal-containing dyes are commonly used in the world. Furthermore, homopolymers such as nitrogen-containing acrylates or heterocyclic compounds or copolymers of these with other vinyl monomers can also be used as charge control agents. These charge control agents may be made to coexist in the polymer slurry, or may be added to the polymer slurry at any stage before drying.

In addition, in order to make the polymerization reaction proceed smoothly, usual suspension polymerization agents such as molecular weight regulators can be optionally used as necessary. Note that the particle size of the produced toner is not particularly limited, but is generally 1 to 30 microns.

The cellulolytic enzyme used in the present invention includes 1,4-β-D-glucan 4-gluconohydrase [
1,4-β-D-Glucan, 4-g:Luc
anohydraaa(]l:03.2.1.4)
], ]1,4-β-D-glucan glucohydrase 11
4-β-D Gluaan gluooh7dral
le(EC3,2,1,74)), 1,4-β-D
- Curcan cellobiohydrolase [1,4-β-D =
Gluaancellobiohydrass (E
O3,2,191) ] and β-D-glucoside glucohydrase [β-D-GluucOa1daluao
hydrasa (11! (35, 2, 1, 21)
] These sources include, for example, Aspergillus, Aepergillus nig.
or ), ) Lycodermaviride (Trlahode)
rma viride), Rhizopus Alhizshui 7
Rh1zopus arrhigu, p FJsc
her ).

Trichoderma ko
nlngi).

conionarium digrothyra (con1other)
iumdiplo+1iella), Aspergillus oryzae
), ) Trametes Sangainea (Trametes
sangulnea), Fusarium moniliforme (
Fusarium Doniliforme), Irbex lacteus (Fusarium Doniliforme)
Or animals that eat plants. The enzymes obtained from each can be used alone or in combination of two or more.

The amount of cellulolytic enzyme used is 0.01 to 10 parts by weight per 100 parts by weight of the cellulose suspension used.

In addition, before using the enzyme, measure the activity to confirm that it has a certain level of activity. The activity is measured by a common method. For example, by reacting a substrate such as carboxymethyl cellulose with an enzyme under certain conditions, the resulting reducing sugar is quantified by the Somogyi method.

Treatment of pigment-containing polymer particles with cellulolytic enzymes can be carried out by adding the enzyme to a slurry during the polymerization reaction or after the completion of the polymerization reaction, or by adding the enzyme to the wet cake or dry polymer particles after dispersing them in water. This is done by adding. When added during the polymerization reaction, in order not to inhibit the polymerization reaction or to obtain toner particles of the desired particle size, the conversion rate of the monomer to the polymer is 10% or more, preferably 20% or more. It is preferable to use the following conditions: 0 Note that enzyme activity varies depending on conditions such as hydrogen ion concentration and temperature, so it is necessary to select treatment conditions suitable for the enzyme used. Generally, the hydrogen ion concentration is in the range of 2 to 10, and the temperature is in the range of 20 to 80°C. A granular electrophotographic toner can be obtained by dehydrating and drying the pigment-containing polymer particles treated in this manner by a conventional method.In addition, in the present invention, one-component and two-component developers are used depending on the purpose of use. Any of these can be manufactured.

(Effects of the Invention) According to the present invention, the suspending agent attached to the polymer particles can be easily removed, and the amount of the suspending agent remaining in one combined particle is small. Because it has good moisture resistance, it has a high electrical resistance even under high humidity conditions and can provide clear images.

(Example) Next, the present invention will be specifically explained using examples.

Note that the number of doses of the drug used is based on weight. Further, toner characteristics were evaluated as follows, and the results are summarized in the table.

Electrical resistance: Prepared toner powder at 10”0, relative humidity 3
0% for 24 hours (standing condition A) and 60°C
, left for 24 hours at 90% relative humidity (standing condition B), molded to a thickness of 2111 mm under a total pressure of 10 tons, and measured with a dielectric loss measuring device at 30"Q and frequency IK.
It was calculated from the conductance value measured under Hz conditions.

Image characteristics: After the electronic copying machine filled with toner powder is left under the above-mentioned storage conditions A or B, a selenium image is formed on the selenium photoreceptor by a normal electrophotographic method, and then developed, and this is developed by corona discharge. The image condition was evaluated by repeatedly transferring the image to paper and fixing it with a hot roller. The evaluation results are initial and 20,000 sheets (2 in Comparative Examples 4B-H).
,000 sheets) The characteristics after transfer are shown below.

Example 1 In a 62 container equipped with a stirrer, 1.6 kg of styrene, 0.4 # of butyl acrylate, 2 kg of magnetite surface-treated with stearoyl chloride, and 80 ml of nigrosine. After mixing at room temperature for 50 minutes with stirring, azobisisobutyronitrile 401 and t-butylmercaptan 40? A homogeneous dispersion was prepared by adding and dissolving.

10, some equipped with rotor-stator type high shear agitators
In a 1-volume reaction vessel, the thermal gelation temperature of a 2% water bath solution is approximately 6
5°C and a viscosity of 50 Cps at 20°C. Aqueous solution 6
kg and the uniform dispersion prepared above and heated to 400.
After stirring for 10 minutes at R, P, M, the inside of the container was degassed.
The atmosphere was replaced with nitrogen, and one reaction was carried out at 60°C. The conversion rate of monomer to polymer was 96%, and the average particle size of the produced particles was 1.
It was 5μ. After collecting the unreacted monomers, a portion of the polymer slurry containing the pigment was adjusted to a hydrogen ion concentration of 50% with ammonia, and trichodermavilide (Trlchod) was added.
erma virids) was added in an amount of 0.5 part per 100 parts of the suspension, stirred at 40° C. for 45 minutes, and then recovered as a toner by dehydration and drying and used for evaluation.

Comparative Example 1 Trichoderma viride (Trichod@rma vir)
A magnetic toner was prepared in the same manner as in Example 1, except that the remaining polymer slurry obtained from (lde) and not treated with the enzyme was dehydrated and dried, and was subjected to evaluation.

・Example 2 As a suspending agent, the thermal gelation temperature change of an aqueous solution of 2-chi is approximately 90°C
A polymer slurry was prepared in the same manner as in Example 1, except that 10 p of hydroxyglopyl methercellulose, which had a viscosity at 20° C. of 100 aps, was used. The conversion rate of monomer to polymer was 97 μm, and the average particle size of the produced particles was 12 μm.

A portion of the obtained polymer slurry was adjusted to a hydrogen ion concentration of 4.0 with aqueous ammonia, and then mixed with Aspergillus niger (As
pergllua nigjr,) was added in an amount of 0.5 part per 100 parts of the suspension, stirred at 50°C for 60 minutes, and recovered as a toner by spray drying, which was used for evaluation.

Comparative Example 2 Aspergillus ni
A magnetic toner was prepared in the same manner as in Example 2, except that the remaining one-coalescence slurry, which was not treated with the enzyme and obtained from the sample (G. gor), was dehydrated and dried, and was subjected to evaluation.

Example 3 As a suspending agent, the thermal gelation temperature of 2 qb hydroxyl solution is about 65
℃, the viscosity at 20℃ is 400 cps, the water bath liquid viscosity of hydroquinlovir mether cellulose 10i and 4tlb is 27-33 cps, and the degree of saponification is 86.5-89
A polymer slurry was obtained in the same manner as in Example 1 except that 0.1 i of polyvinyl alcohol of 0 mol. The conversion rate of monomers into monomers was 95%, and the average particle size of the produced particles was 18 μm.

A part of the obtained 1-coalescence slurry was adjusted to a hydrogen ion concentration of 4.0 with aqueous ammonia, and then mixed with Aspergillus niger (Aspergillus niger).
Pergillus niger) was added in an amount of 0.5 parts per 100 parts of the suspending agent, stirred at 50° C. for 60 minutes, and then recovered as a toner by dehydration and drying and used for evaluation.

Comparative Example 5 Aspergillus niger (AIipergillus n.
A magnetic toner was prepared in the same manner as in Example 3, except that the remaining polymer slurry that was not subjected to the enzyme treatment (obtained from P. iger) was dehydrated and dried, and was subjected to evaluation.

Example 4 As monomers, 1.7 kg of styrene, butadiene o, 3
A polymer slurry was prepared in the same manner as in Example 1, except that magnetite) 2# without surface treatment with stearoyl chloride was used. The conversion rate of monomer to polymer was 97 μm, and the average particle size of the produced particles was 15 μm. A part of the obtained one-coalescence slurry was adjusted to a water bulk ion concentration of 5.0 with hydrochloric acid, and trichodermaviride (Tric'
Hoclerma virids) was added in an amount of 07 parts V'1 per 100 parts of the suspending agent, stirred at 45° C. for 45 minutes, and then recovered as a toner by dehydration and drying and used for evaluation.

Comparative Example 4 Trichoderma viride (Triahoderma viride)
A magnetic toner was prepared in the same manner as in Example 4, and was subjected to evaluation.

As is clear from the evaluation results of the toner shown in the table, the toner obtained by the present invention has high electrical resistance and excellent image characteristics not only under low temperature and low humidity conditions but also under high temperature and high humidity conditions.

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Claims (1)

[Claims] Electrophotography characterized by polymerizing at least one monomer in an aqueous medium in the presence of a pigment using a cellulose suspending agent, and treating the resulting pigment-containing polymer particles with a cellulolytic enzyme. method for producing toner for use in