JPH05249732A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To ensure stable satisfactory electrostatic chargeability over a long period of time, to well inhibit filming on a photosensitive body and spending on a carrier and to form satisfactory copied images over a long period of time. CONSTITUTION:This toner for developing an electrostatic charge image contains binding resin-based resin particles obtd. by dispersion polymn. and having a phenolic resin deriv. or a copolymer of a vinyl monomer contg. a sulfonic acid group stuck to the surfaces of the particles or contg. a low mol.wt. phenol deriv. or a phosphorus-contg. antioxidant dispersed in the particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic charge image (electrostatic latent image) formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.

[0002]

2. Description of the Related Art As means for developing an electrostatic latent image formed on an electrophotographic photosensitive member or an electrostatic recording member, a method using a liquid developer (wet developing method) and a method using a binder resin dye,
A toner in which a colorant such as a pigment is dispersed, or a method using a one-component or two-component dry developer in which the toner is mixed with a solid carrier (dry development method) is generally adopted. Although each of these methods has advantages and disadvantages, at present, the dry developing method is widely used.

Toners used in the dry development method are generally dyes and pigments and various metal complex salts, in order to control the triboelectric chargeability.
Add charge control substances such as quaternary ammonium salt, knead,
It is manufactured by crushing and classifying. In the toner thus manufactured, the charge control substance is almost uniformly dispersed in the particles, and it can be said that the toner charge control method is well established.

In recent years, in order to provide high image quality and high durability, it has been required to reduce the particle size of toner, sharp particle size distribution, sufficient coloring power, and uniform charge control. That is, reducing the particle size of the toner improves quality such as resolution, sharpness, halftone reproducibility, and photographic reproducibility. Further, when the particle size distribution is sharp, halftone reproducibility and photographic reproducibility are particularly improved. Further, even if the toner is used for a long time, the particle size distribution of the toner in the developer does not change, so that the stability of the image quality and the long life of the developer are brought about. For this reason, attention has been paid to a toner in which resin particles obtained by dispersion polymerization or suspension polymerization and having a small particle size and a narrow particle size distribution are used as base particles.

However, in the case of a toner obtained by a dispersion polymerization method, a suspension polymerization method or the like, since the manufacturing method thereof is significantly different from that of a kneading type toner, a new toner suitable for the toner charge control method is also suitable. Establishing a method is required. For example, after washing and drying the polymer particles, it is attempted to dry-mix the charge control agent with the polymer particles and then drive the charge control agent onto the surface of the polymer particles, or dye the charge control agent used in the kneading method during the polymerization. ing.

[0006]

However, since the toner obtained by the implantation method does not sufficiently fix the charge control agent on the surface of the toner, there is a problem in quality over time, and it is difficult to put it into practical use. Further, when the charge control agent used in the kneading method is dyed, the charge control agent cannot be diffused into the inside of the polymer particles because of the large chemical structure of the charge control agent, and therefore, the sufficient charge control ability is obtained. It is the current situation that is not obtained.

Further, in the case of the toner obtained by the dispersion polymerization method, the polymer dispersant remains on the surface, and the chargeability is governed by this residual polymer dispersant. When the surface on which the polymer dispersant remains is negative, a negative chargeability is obtained as a toner, but the rise of charge is poor and it is not sufficiently satisfied. Therefore, it is conceivable to add a negative compound in the solution to the surface of the negatively-dispersed polymerized particles, but it is not possible to give a strong negative electrification property by such a method because of large ionic repulsion. ..

Therefore, an object of the present invention is to solve the above-mentioned problems, that is, to electrostatically develop an electrostatic charge image which gives toner particles stable and appropriate chargeability for a long period of time and provides a good copy image permanently. To provide a toner for use.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that a low molecular weight phenol derivative or the like is dispersed in a toner in which a phenol resin derivative or the like is attached to the surface of a polymer resin particle or the inside of the particle. The present inventors have found that such toners meet the above-mentioned object, and have completed the present invention.

That is, according to the present invention, in an electrostatic charge image developing toner comprising resin particles containing a binder resin as a main component, the resin particles are resin particles obtained by a dispersion polymerization method, and There is provided a toner for developing an electrostatic charge image, which is obtained by adhering a copolymer of a phenol resin derivative or a sulfonic acid group-containing vinyl monomer on the surface of resin particles.

Further, according to the present invention, in the toner for developing an electrostatic charge image comprising resin particles containing a binder resin as a main component, the resin particles are resin particles obtained by a dispersion polymerization method, and Provided is a toner for developing an electrostatic charge image, characterized in that a low molecular weight phenol derivative or a phosphorus element-containing antioxidant is diffused inside resin particles.

In the toner of the present invention, a phenol resin derivative or a copolymer of a sulfonic acid group-containing vinyl monomer is attached to the surface of polymer resin particles, or a low molecular weight phenol derivative or phosphorus element-containing oxide is formed inside the polymer resin particles. By diffusing the inhibitor, it has good charging characteristics, and it is possible to obtain sufficiently satisfactory results in terms of charge rise, saturated charge amount, quality over time, and the like.

The toner of the present invention will be described in detail below. The toner of the present invention has a method in which a phenol resin derivative or a copolymer of a vinyl monomer having a sulfonic acid group is adhered to the surface of resin particles obtained by dispersion polymerization as described above, or a low resin is added to the inside of the resin particles. A molecular weight phenol derivative or a phosphorus element-containing antioxidant is diffused. In this case, the adhesion means that the charge control compound (mostly a polymer) is present only on the toner particle surface, and the diffusion Means that the charge control compound (often a low molecular weight compound) is present on the surface and inside of the toner particles.

When the charge control agent is attached to the surface of the toner particles, it is impossible to uniformly attach the charge control agent solution to the surface of each particle simply by mixing the resin particles dispersed in the liquid with the charge control agent solution. is there. According to the research of the inventor,
In order to uniformly attach the charge control agent, when the desired chargeability is negative, polymer particles are prepared using a positive polymer dispersant, and a charge control compound solution is added to the particles, It was found that an ion complex was formed and the charge control compound was firmly fixed on the surface of the polymer particles, and a toner having sufficient charge control ability was obtained.
The amount of the charge control agent attached is preferably 0.1 to 5% by weight.

Further, when the charge control compound is diffused inside the resin particles, it is necessary to remove or modify the negative compound existing on the surface of the resin particles in advance. According to the study of the present inventor, it is possible to disperse the charge control compound inside the polymer particles by dispersing the resin particles in an alkaline solution, washing the resin particles, and then adding the charge control compound solution. It was revealed. In this method, first, negative resin particles are dispersed in sodium hydroxide solution (pH 12), and then water / methanol = 1.
Filter and wash with the / 1 mixed solution. Next, the charge control compound solution is added and treated at about 50 ° C. for about 1 hour. By this method, it becomes possible to impart sufficient charge controllability to the toner. The addition amount of the charge control compound is preferably 0.5 to 10% by weight.

Generally, styrene resins, acrylic acid resins, polyesters, etc. are used as the binder resin of the toner. Since these compounds hardly hold an ionic group, the charge control agent having an ionic group cannot be diffused inside the resin particles. Therefore, the charge control material that diffuses into the resin needs to be a material that does not dissociate ions. On the other hand, when the charge control agent is attached to the surface of the resin particles, it is necessary that the resin particles have a polarity opposite to the desired polarity as described above.
Therefore, when the charge controllability of many materials was evaluated, it was found that in polymer systems, copolymers of vinyl monomers containing phenolic resin derivatives or sulfonic acid groups and other vinyl monomers have charge controllability for resin particles. It turned out to be excellent. Further, it was found that the low molecular weight compound is preferably an antioxidant having a phenol derivative or a phosphorus element, and can be diffused inside the resin particles.

The phenol resin derivative used in the present invention contains at least 50 phenol units in total.
A copolymer may be used as long as it accounts for at least%. Examples of the phenol resin derivative used in the present invention include phenol resin, p-tert-butyl-phenol resin, p-methyl-phenol resin, and m-cresol resin. Further, as the copolymer having a vinyl monomer having a sulfonic acid group, the monomer unit having a sulfonic acid group may occupy 1 to 80%. For example, as a vinyl monomer containing a sulfonic acid group, p is
-Sodium styrene sulfonate, sodium o-styrene sulfonate, potassium salts thereof, and the like.

As the low molecular weight phenol derivative,
2,6-ditert-butyl-p-cresol, 4,
4'-butylidene bis (3-methyl-6-tert-butylphenol), n-octadecyl-3- (4-hydroxy-3,5-ditert-butylphenyl) propionate, tetrakis [methylene-3- (3,5- The t
ert-butyl-4-hydroxyphenyl) propionate] methane and the like can be used, but the invention is not limited thereto. Further, as the antioxidant having a phosphorus element, distearyl pentaerythritol diphosphite, tris (2,4-ditert-butylphenyl) phosphite, dibehenyl pentaerythritol diphosphite, dipalmityl pentaerythritol diphosphite. Phyto, tris (2,4,6-tritert-butylphenyl) phosphite, tris (4-tert-butylphenyl) phosphite and the like can be used, but not limited thereto.

Examples of the monomer forming the binder resin used in the toner of the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene and p.
-Ethylstyrene, 2,4-dimethylstyrene, pn
-Butyl styrene, p-tert-butyl styrene, p
-N-hexyl styrene, pn-octyl styrene,
pn-nonylstyrene, pn-decylstyrene, p
-N-dodecylstyrene, p-methoxystyrene, p-
Styrenes such as phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene; ethylene, propylene,
Ethylene unsaturated monoolefins such as butylene and isobutylene; vinyl chloride, vinylidene chloride, vinyl bromine,
Vinyl halides such as vinyl fluoride; Vinyl esters such as vinyl acetate and vinyl propionate; α-methylene fatty acids such as methyl acrylate, ethyl acrylate, -n-butyl acrylate, methyl methacrylate, ethyl methacrylate Monocarboxylic acid esters; vinyl ethers such as vinyl methyl ether; vinyl ketones such as vinyl methyl ketone; N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc. can do. These monomers can be used alone or in combination of two or more kinds.

As the monomer for forming the polycondensation type resin, for example, ethylene glycol, triethylene glycol, 1,2-propylene glycol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, Polyhydric alcohols such as polyoxypropylene bisphenol A; ethylenediamine,
Polyvalent amines such as tetramethylenediamine and piperazine;
Maleic acid, fumaric acid, mesaconic acid, citraconic acid,
Examples thereof include adipic acid, malonic acid, their acid anhydrides, and esters with lower alcohols. The present invention is not limited to the resin monomer shown here.

Additives such as colorants may be used in the toner of the present invention, which include metal chelate dyes such as carbon black, oil black, nigrosine dyes, metal-containing dyes, aniline dyes, and chalcone dyes. Oil blue, chrome yellow, ultramarine blue, methylene blue chloride, phthalocyanine blue, rose bengal, and other dyes or pigments are included.

Further, the toner of the present invention may contain a fluidizing agent, if necessary. For example, inorganic oxides such as SiO ₂ and TiO ₂ whose surfaces are made hydrophobic; inorganic fine particles such as SiC. A metal soap such as zinc stearate or the like may be used.

When the toner of the present invention is used as a two-component developer, it is used as a mixture with carrier powder. As the carrier in this case, all known carriers can be used, for example, iron powder, ferrite powder, magnetic powder such as nickel powder, glass beads, and those whose surface is treated with resin or the like. Can be mentioned.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. The parts shown below are based on weight.

Example 1 First, resin particles were produced by the dispersion polymerization method as follows. That is, 320 parts of methanol was placed in a three-necked flask equipped with a stirring blade and a condenser, and 6.4 parts of a polymer dispersant polyvinylpyrrolidone (average molecular weight 40,000) was added little by little with stirring to completely dissolve it. It was Further, the following composition was added and completely dissolved. Styrene 25.6 parts n-Butyl methacrylate 6.4 parts 2,2'-Azobisisobutyronitrile 0.2 parts

While stirring these, the inside of the flask was purged with nitrogen gas and left for 1 hour. Polymerization was started while stirring at a stirring speed of 200 rpm in a constant temperature water bath of 60 ° C. ± 0.1 ° C. After 15 minutes of heating, the liquid became cloudy. The solution was a cloudy and stable dispersion even after 20 hours of polymerization. As a result of partially sampling and measuring by gas chromatography by the internal standard method, it was confirmed that the polymerization rate was 92%.

When the obtained dispersion was cooled and centrifuged at 2000 rpm with a centrifuge, the polymer particles were completely settled and the upper liquid was transparent. The supernatant was removed, 200 parts of methanol was newly added, and the mixture was stirred and washed for 1 hour.
The procedure of centrifuging and washing with methanol was repeated and filtered. The material separated by filtration was dried under reduced pressure at 50 ° C. for 24 hours to obtain styrene / n-butyl methacrylate copolymer particles as white powder in a yield of 95%. The obtained particles had a volume average particle diameter Dv = 5.50 μm. Also, Tg is 7
The temperature was 3 ° C. [Hereinafter, the polymer particles are referred to as (A). ].

Next, 1.0 part of Oil Black 803 (Orient Chemical Co., Ltd.) was dissolved by heating in 200 parts of methanol, cooled, and filtered with a 1 μm filter to prepare a dye solution. Subsequently, 24 parts of the polymer particles (A) were added to and dispersed in the filtrate, and heated and stirred at 50 ° C. for 1 hour. Then, the dispersion liquid was cooled to room temperature and filtered to obtain colored resin particles, and the particles were again dispersed in methanol to obtain a dispersion liquid.

Next, a phenol resin was completely dissolved in methyl cellosolve, and then a solution containing methanol was prepared. This solution was added to the redispersion solution so that the phenol resin solid content was 2 parts with respect to 100 parts of the colored resin particles, and the mixture was stirred for 1 hour, filtered, and dried to obtain a toner.

Example 2 The polymer dispersant used in Example 1 was a copolymer of methyl vinyl ether and maleic anhydride (Gantrez: average molecular weight 4).
Colored resin particles were prepared in the same manner as in Example 1 except that the amount was changed to 10,000). This colored resin particle dispersion solution was mixed with a sodium hydroxide solution (pH 12) and filtered and washed with a water / methanol solution. Then, n-octadecyl-3- (4-hydroxy-3,5-ditert-butylphenyl) propionate is dissolved in methanol,
N-Octadecyl-3-based on 100 parts of the colored resin particles
(4-Hydroxy-3,5-ditert-butylphenyl) propionate was added in an amount of 1 part, stirred at 50 ° C. for 1 hour, filtered and dried to obtain a toner.

Example 3 Colored resin particles were prepared in the same manner as in Example 1. Next, a copolymer of sodium p-styrenesulfonate and tert-butyl acrylate (copolymerization ratio 10/90)
Was dissolved in methanol, and the above copolymer was added to 1 part of 100 parts of the colored resin particles, stirred for 1 hour, filtered, and dried to obtain a toner.

Example 4 By the same method as in Example 2, colored resin particles washed with alkali were prepared. Next, distearyl pentaerythritol diphosphite was dissolved in methanol and added so that the amount of distearyl pentaerythritol diphosphite was 1.6 parts with respect to 100 parts of the colored resin particles.
After stirring for 50 hours at 50 ° C., it was filtered and dried to obtain a toner.

Comparative Example Colored resin particles were prepared in the same manner as in Example 1 and used as a toner.

(Evaluation) The toners obtained in the above Examples and Comparative Examples were mixed with a Cu—Zn ferrite carrier (3 parts of toner, 97 parts of carrier), and an image was formed by using a copying machine Imagio 420 manufactured by Ricoh. The toner was formed and the charging characteristics of the toner at that time were measured by the blow-off method.
The results are shown in Table 1.

[0035]

[Table 1] Charging characteristics

It can be seen from Table 1 that the toner of the present invention stably maintains an appropriate amount of charge for a long period of time. During the test, neither filming on the photoconductor nor spent on the carrier was observed.

[0037]

The toner for developing an electrostatic charge image of the present invention comprises resin particles obtained by a dispersion polymerization method containing a binder resin as a main component, and the surface of the particles contains a phenol resin derivative or a sulfonic acid group. Since a vinyl monomer copolymer is attached or a low molecular weight phenol derivative or a phosphorus element-containing antioxidant is diffused inside the above particles, when the toner is used for image formation, Stable and good charging characteristics are obtained over a long period of time, and filming on the photoconductor is sufficiently suppressed, so that a good copied image can be obtained for a long period of time.

Claims (2)

[Claims] 1. A toner for developing an electrostatic charge image comprising resin particles containing a binder resin as a main component, wherein the resin particles are resin particles obtained by a dispersion polymerization method, and the surface of the resin particles is phenol. A toner for developing an electrostatic charge image, comprising a resin derivative or a copolymer of a vinyl monomer having a sulfonic acid group attached thereto. 2. An electrostatic charge image developing toner comprising resin particles containing a binder resin as a main component, wherein the resin particles are resin particles obtained by a dispersion polymerization method, and the inside of the resin particles is low. A toner for developing an electrostatic charge image, which is obtained by diffusing a molecular weight phenol derivative or a phosphorus element-containing antioxidant.