JPS63249153A - Powder toner - Google Patents

Abstract

PURPOSE:To improve the hydrophilicness of a toner surface and to enable low pressure fixing by encapsulating each particle of a pressure-fixable core material with a shell formed by interfacial polymerization, and then, coating it with a resin. CONSTITUTION:Each pressure-fixable core particle is encapsulated with the shell formed by the interfacial polymerization, then, mixed with an aqueous resin dispersion to attach the resin to the outer surface of each capsule and to coat it. Since the toner is encapsulated, fixing can be carried out with low pressure, and the capsules can be coated in an aqueous dispersion without drying and disintegration steps, and an emulsion obtained by the emulsion polymerization can be directly used for said aqueous dispersion as it is without any processing, and since the steps of drying and collection of the powder for pulverizing are made unnecessary, manufacturing cost is cut down, and it is easy to uniformly attach the resin to the surface of the capsules. The toner good in humidity resistance can be obtained even when a dispersion stabilizer and the like used for emulsifying the core material remains on the surface of the capsules.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a powder toner used in a method of converting an electrostatic latent image into a visible image in electrophotography, ion flow recording method, etc. .

More specifically, the present invention relates to a capsule toner that is easily fixed on a paper surface or the like by pressure applied to a shell formed by an interfacial polymerization method.

(Prior art) As a powder toner for converting an electrostatic latent image into a visible image, 1
A common method is to disperse dyes, pigments, magnetic powders, etc. in toner resin by melt-kneading, mechanically crush the resultant after cooling, and then classify.

However, it has been pointed out that the toner obtained by this method has drawbacks such as being amorphous, making it difficult to obtain a uniform charge, and having poor mobility.

Furthermore, in manufacturing, the consumption of electrical energy required for melting, kneading, and pulverization is enormous, and attempts are being made to obtain powder toner by methods other than so-called pulverization.

Spray drying methods, emulsion polymerization methods, suspension polymerization methods, interfacial polymerization methods, and the like are known as methods for producing powder toners other than the so-called pulverizable method, which are produced by the above-mentioned melt-kneading and subsequent pulverization.

However, since the spray drying method produces a single spherical toner, uniform charge can be obtained and fluidity is good, but it requires explosion-proofing of the spray dryer and recovery of the solvent. However, there are drawbacks such as the large amount of thermal energy consumed during drying, and the fact that the solvent remains in the toner even after drying and is difficult to remove.Furthermore, it is difficult to impart sufficient physical properties to the toner.

Due to limitations on materials, it is difficult to obtain toners with sufficient properties using only this method.

In addition, by emulsion polymerization method, suspension polymerization method, interfacial polymerization method, etc.
Various methods of producing spherical toner particles in water have been studied, but the dispersing and stabilizing materials used during the production of toner particles in water remain on the surface of the toner particles and are difficult to remove. It has been pointed out that the toner absorbs moisture and lowers the electrical resistance of the toner, making it difficult to copy on plain paper, and also makes the charge on the toner surface non-uniform. Furthermore, it has been pointed out that bispherical particles have poor cleaning properties on the surface of a photoreceptor.

Also, it can be used to speed up electrophotography.

In unmanned machines such as facsimile machines, the conventional method of fixing by heating has been replaced by a method of fixing by crushing toner with a pressure roll.

This method does not require warm-up of the machine and requires less energy for fusing.

It can also handle higher speeds.

However, the above-mentioned fixing method using a pressure roll.

Compared to fixing methods that use heated rolls, the toner fixing properties are poor, and the toner printed area is susceptible to bending.

It has the drawbacks of being extremely shiny and easily peeling off.

Additionally, conventional pressure rolls use high pressure to crush toner, making them heavy.

Alternatively, it has been pointed out that the paper that has passed through the pressure rolls has a glossy appearance or that the strength of the paper is reduced.

As a toner intended to solve these drawbacks, there is a microcapsule type toner whose core material is a two-liquid or soft solid pressure fixing substance, and this has also been studied.

This microcapsule toner can be made into 9-spheres compared to conventional pressure-fixable toners with a single structure, which are produced by freezing and crushing pressure-fixable substances.
Fixing at low pressure is also possible, and furthermore, since exposure of the pressure fixing substance is eliminated, problems such as toner aggregation and blocking may be reduced. Such microcapsule toners are described in US Pat. No. 3,080,250, 3
080251.3080318. Japanese Patent Publication No. 48-7164
8.48-75032.51-80235.51-81
134.51-124435゜52-82239.52
-113740.54-76233.54-11824
No. 9.58-66948.59-148066 and the like have been disclosed.

The present inventors have investigated various methods for microencapsulation, and found that encapsulation using interfacial polymerization can be performed in a short time at room temperature under atmospheric pressure, and does not require special equipment. We drew attention to this method because it has the advantage of being able to perform

However, as mentioned above, this method has a disadvantage of a decrease in electrical resistance at high temperatures because particles are obtained by polymerizing in water.

As a method for treating the surface of such toner, Japanese Patent Application Laid-open No. 5
No. 4-76233 discloses a method of treating residual polyvinyl alcohol with a melamine condensate to insolubilize it.

Further, a method of precipitating a ketone-aldehyde resin on the surface of a toner by a coacervation method is disclosed.

However, even if residual polyvinyl alcohol is insolubilized, there are problems such as not being able to obtain sufficient electrical resistance of the toner, and the coacervation method requires the use of an organic solvent, and other easy processing methods cannot be used. was needed.

(Problems to be Solved by the Invention) The present invention provides a capsule toner that can be fixed at low pressure by improving uneven charging on the toner surface, hydrophilicity of the toner surface, and poor triboelectric charging properties due to decreased resistance. The purpose is to easily obtain.

[Structure of the invention]

(Means for Solving the Problems) The present invention encapsulates a core material having pressure fixing properties with a shell formed by interfacial polymerization, and then mixes it with an aqueous resin dispersion to form a core material on the outer surface of the capsule. The present invention relates to a powder toner characterized in that a resin in the aqueous resin dispersion is adhered to a powder to coat a capsule.

In the present invention, the core material having pressure fixing properties flows out from the capsule when the capsule is ruptured.

Alternatively, it is a liquid or soft solid that is extruded, and is composed of colorants such as dyes and pigments, magnetic powder, a binder, a solvent, and the like.

As colorants, dyes and pigments conventionally used in toner materials are used, such as zinc yellow, yellow iron oxide, Hansa yellow, disazo yellow, and quinoline yellow.

Permanent Yellow, Permanent Red, Red Garla, Risol Red, Wochan Red Ca Salt, Wochan Resod Mn Salt, Pyrazolone Red 1, Laked C, Laked D, Prilliant Carmine 6B.

Pigments or oil-soluble dyes such as brilliant carmine 3B, navy blue, phthalocyanine blue, metal-free phthalocyanine, titanium oxide, and carbon black can be used.

As the magnetic powder, alloys or compounds of iron such as various ferrites, magnetites, hematites, zinc, cobalt, nickel, manganese, etc. can be used.

These magnetic powders are preferably spherical to cubic, octahedral, acicular, etc., and have an average particle diameter of 0.1 to 0.5 microns, and are surface-treated to ensure good dispersion in the resin solution. , hydrophobic treatment with fatty acids, etc.

It may be subjected to silane coupling agent treatment, resin coating treatment, etc.

The binder has the function of (1) dispersing and holding the colorant or magnetic powder etc. well and fixing a visible image on the paper surface, such as ethylene-vinyl acetate copolymer, polystyrene,
Copolymers containing styrene with styrene and acrylic esters, methacrylic esters, acrylonitrile or maleic esters, polyacrylic esters, polymethacrylic esters, polyesters, polyamides, polyvinyl acetate, epoxy systems Examples include resins such as phenol, hydrocarbon, petroleum, etc., and these can be used alone or in combination.

We also use polyethylene wax, polypropylene wax, and microcrystalline wax as waxes.

Paraffin wax, oxidized wax, vegetable wax.

Examples include animal wax and mineral wax, which can be used alone or in combination as required.

The solvent is preferably one that dissolves or swells the binder, but a solvent that does not dissolve the binder can also be used as part of the solvent.

Examples of solvents include phthalate esters, phosphate esters, fatty acid esters, benzoate esters, citric esters, diarylalkanes, alkylphenyl ethers, polybutene, vegetable oil, and toluene.

Hydrocarbon solvents such as xylene can be used.

Note that the core material of the present invention may contain various additives, if desired.9 For example, tin octenoate.

Catalysts such as dibutyltin dilaurate, silicon compounds.

Examples include mold release agents made of fluorine compounds.

The above core material is prepared by adding colorants, magnetic powder, binders, solvents, and other additives to ball mills, attritors, dyno mills, etc.
It can be obtained by heating or cooling and dispersing as necessary using a dispersing machine such as a three-roll mill.

In the present invention, interfacial polymerization is carried out by dissolving and dispersing a hydrophobic polymerizable compound in the core material, mixing and stirring with an aqueous medium containing two dispersion stabilizers, and emulsifying the mixture. Polymerization is carried out with a hydrophobic polymerizable compound.

Examples of the hydrophobic polymerizable compounds include phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate,
Dimethoxybiphenyl diisocyanate, dimethyldiphenylmethane diisocyanate, xylylene diisocyanate, diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, pro and diisocyanate, butylene diisocyanate, ethyridine diisocyanate, cyclohexylene diisocyanate, tolylene diisocyanate, triphenylmethane triisocyanate , polymethylene polyphenylisocyanate.

Dimethyldiphenylmethane tetraisocyanate, polyisocyanate prepolymer, tetramethylene diisothiocyanate, hexamethylene diisothiocyanate, p-phenylene dithiocyanate xylene-1,
Urethane and urea resin shell-forming compounds such as 4-diisothiocyanate and ethyridine diisocyanate;
Epoxy shell-forming compounds commercially available under trade names such as Epicote, oxazoloyl chloride, succinoyl chloride, adipoyl chloride, sebacoyl chloride, phthaloyl chloride, isophthaloyl chloride, fumaroyl chloride, Cyclohexane dicarbonyl chloride, polyester with acid loride group, polyamide, benzenedisulfonyl chloride,
Naphthalene disulfonyl chloride, oxybisbenzenedisulfonyl chloride, hexanedisulfonyl chloride, ethylene bis(chloroformate), tetramethylene bis(chloroformate), 2,2'-dimethyl-1,3-propane bis(chloroformate) Polyamide-based shell-forming compounds such as p-propane bis(chloroformate) and p-propane bis(chloroformate) are used, and these can be used singly or in combination of two or more.

These compounds can be added when preparing a dissolved dispersion of the core substance, but they can also be added when producing the dissolved dispersion of the core substance.
It is preferable to add it to the dissolved dispersion of the core substance immediately before mixing and stirring with water containing a dispersion stabilizer. The above-mentioned core material and polymerizable compound are mixed together in a dispersion liquid.

Mix and stir with an aqueous medium containing a dispersion stabilizer.

Dispersion stabilizers include polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose, cellulose gum, silica fine powder,
These include water-soluble polymer compounds such as sodium lauryl sulfate and sodium oleate, gold i oxide, and surfactants.

These dispersion stabilizers have the effect of making each particle smaller and making the particle size more uniform.

Mixing and stirring is carried out by adding a dissolved dispersion of the core substance to an aqueous medium containing two dispersion stabilizers, or vice versa.

Any method in which an aqueous medium containing a dispersion stabilizer is added to the dissolved dispersion can be used.

Mixing and stirring can be performed using a high-speed stirrer, an ultrasonic disperser, or the like. As a high-speed stirrer, a homomixer, homogenizer, colloid mill, homodisper, etc. can be used, and stirring is performed at several thousand revolutions or more.

The above-mentioned emulsification by mixing and stirring can be carried out at room temperature, but conditions such as heating, reduced pressure, or increased pressure can also be added if necessary.

In addition, when isocyanate is used as a hydrophobic polymerization compound, it is heated in the presence of a catalyst after emulsification.

It is preferable to carry out a reaction between isocyanate and water because it strengthens the capsule membrane.

Furthermore, when the viscosity of the core material is lowered using a low-viscosity solvent in order to reduce the particle size by mixing and stirring, heating may be applied to remove the viscous solvent from the core material. It is valid.

As described above, a finely divided spherical core material is produced in the aqueous medium.

A hydrophilic polymerizable compound that undergoes a polymerization reaction with the hydrophobic polymerizable compound is added to the aqueous medium while continuing to stir gently to the extent that the core material in the aqueous medium does not precipitate.

As a hydrophilic compound that undergoes such a polymerization reaction.

Ethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, phenylene diamine, 2-hydroxytrimethylene diamine.

Polyamines such as diethylenetriamine, triethylenetetramine, diethylaminoprobylamine, and tetraethylenepenkune, piperazine, and methylbiperazine.

Piperazines such as dimethylpiperazine, ethylene glycol, catechol, resorcinol, and hydroquinone.

Dihydroxymethylbenzene, dihydroxyethylbenzene, naphthalene diol, polythiol, etc. are used.

This polymerization reaction proceeds even at room temperature, but heating is also acceptable.

In addition, when using a polybasic acid as a hydrophobic polymerizable compound, it is preferable to add a small amount of an acid neutralizer such as sodium carbonate.

After the polymerization reaction is completed, the remaining hydrophilic polymerizable compound 5 dispersion stabilizer and the like are washed.Washing is performed by washing with water, washing with warm water, etc., and decantation or decantation 3 to 4 times.

An example of this is centrifugation.

The particles encapsulated by interfacial polymerization are mixed with an aqueous resin dispersion in which fine resin particles that become hydrophobic upon drying are dispersed in water, and the resin in the resin dispersion is attached to the outer surface of the capsule. Coat the capsule.

As such an aqueous resin dispersion, a dispersion produced by so-called soap-free emulsion polymerization that does not contain an activator or the like can be used as it is or after being concentrated.

Dispersions obtained by such soap-free emulsion polymerization are disclosed in JP-A-58-127702.59-1503.
．． It is obtained by the technique disclosed in Publication No. 59-199703, etc., but the number of dispersed particles is 0.01.
It is preferable that the particles be spherical and have a uniform particle size of about 1 μm to obtain a uniform coating.

In addition, the resin in the resin dispersion liquid is a styrene-methyl methacrylate copolymer, which coats the outer surface of the capsule and contributes to improving the moisture resistance of the toner or improving the fixing properties of the capsule shell. Isobutyl methacrylate
Methyl methacrylate copolymer and the like are preferred.

Furthermore, it is also effective to use two or more types of aqueous resin dispersions for the purpose of multifacetedly changing the properties of the outer surface of the toner using fine resin particles having different properties.

In addition, those obtained by polymerizing the following vinyl monomers can also be used.

That is, examples of vinyl monomers include styrene monomers such as styrene, vinyltoluene, 2-methylstyrene, and t-butylstyrene, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. Methyl methacrylate, ethyl methacrylate.

Propyl methacrylate, n-butyl methacrylate.

Acrylic acid or methacrylic acid alkyl esters such as isobutyl methacrylate and 2-ethylhexyl methacrylate, monobasic acids such as acrylic acid, methacrylic acid, and crotonic acid, dibasic acids such as fumaric acid, itaconic acid, and maleic acid, or their anhydrides. Ethylenically unsaturated carboxylic acid monomers such as N-methylol acrylamide, N-methylol methacrylamide.

N-substituted (meth)acrylic monomers such as N-butoxymethylacrylamide and N-butoxymethylmethacrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate,
Examples include hydroxyl group-containing monomers such as hydroxypropyl methacrylate, and epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate.

The resin dispersion liquid contains capsules 10 obtained by interfacial polymerization.
A solid content ratio of 0.3 to 10 parts by weight is used relative to 0 parts by weight. If it is less than 0.3 parts by weight, the surface of the capsule cannot be sufficiently coated, and if it is more than 10 parts by weight.

You can't get the desired effect by just adding it. Furthermore, there is a possibility that the capsules may aggregate with each other.

The method of attaching the resin of the resin dispersion to the surface of the capsule and coating the surface of the capsule is to mix the aqueous resin dispersion with the aqueous dispersion of the capsule, stir it, and dry it with a spray dryer. It is obtained by

Furthermore, during spray drying, even if the resin particles in the resin dispersion do not adhere to the outer surface of the capsule and are partially mixed into the toner, the resin particles will still function as a charging aid. A desirable effect can be obtained.

In addition, without using a spray dryer, remove moisture by filtration etc., dry by vacuum drying, hot air drying etc., and then,
The powder toner of the present invention can also be obtained by crushing the dried material.

In addition, after mixing the capsule dispersion obtained by interfacial polymerization and the aqueous resin dispersion, the capsules can be formed by adding a solvent, heating for sub-adjustment of pH, or charging a single particle by cooling and agglomerating. An operation may be used in which a resin in an aqueous resin dispersion is attached around the surface.

In the present invention, a charge control agent can be used in the core material or the outer shell of the capsule for charge control.

As such charge control agents, oil-soluble dyes, metal-containing dyes, acid dyes, naphthenic acid metal salts, fatty acid metal soaps, etc. are used.

In addition, hydrophobic silica is used for the purpose of improving fluidity, and carborundum, alumina, cerium oxide, etc. are used as abrasives.

Further, as a lubricant, metal soap powder, fine particles of polyvinylidene fluoride, polytetrafluoroethylene, etc. can also be used.

Two embodiments of the present invention will be described below. In the examples, 2 parts indicate parts by weight.

Example 1 Synthetic wax (Sunwax 131-P manufactured by Sanyo Chemical Industries) 5 parts Ethylene-vinyl acetate copolymer (containing 30% vinyl acetate) 5 parts Petroleum resin (Coholex #2100 Toho Oil Resin) 5 parts Dioctyl phthalate 10 parts High boiling point solvent (Hisol 100, manufactured by Nippon Petrochemicals) 20 parts Magnetic powder (EPT-500, manufactured by Toda Kogyo) 40 parts The mixture of the above formulation was dispersed in a three-roll mill to obtain a soft ink-like material. (Ink A) After adding and mixing 70 parts of isocyanate (Millionate MR-200 manufactured by Nippon Polyurethane ■) to 300 parts of this ink A, 111 parts of 0.75% polyvinyl alcohol water was added and mixed.
In addition to 200 parts, emulsification was performed at 110,000 rpm for 5 minutes using a colloid mill (Desktop colloid mill manufactured by Nippon Seiki ■).

After emulsification, the emulsion was transferred to another container, and while stirring at a low speed, 180 parts of a 10% diethylenetriamine aqueous solution was added, and stirring was continued for 3 hours to produce microcapsules by interfacial polymerization reaction.

After standing overnight, the supernatant liquid was removed, and the operations of stirring and washing with 50°C warm water and decantation were repeated four times.

The pH of the emulsion was set to about 6.

After removing the supernatant liquid so that the microcapsule solid content of the emulsion was 30%, the aqueous resin dispersion (VE-2
A 20% spherical dispersion of 029 styrene-methyl methacrylate copolymer (manufactured by Soken Kagaku ■) having a particle size of about 0.4 μm was mixed in an amount of 3% based on the solid content of the microcapsules.

The above mixture was spray-dried at an inlet temperature of 140° C. using a spray dryer (Palvis GA-31 manufactured by Yamato Kagaku ■).

Colloidal silica (R
-972 manufactured by Nippon Aerosil ■) was added at 0.3%.

Commercially available copier (U-BiX120 manufactured by Konishiroku Photo Industry)
A printing test was conducted using 0), and when the unfixed image was fixed using a pressure roll, a good image without fogging could be obtained.

Comparative Example 1 In Example 1, spray drying was performed without adding an aqueous resin dispersion. Colloidal silica (R-972
A test similar to that of Example 1 was carried out by adding 0.3% of Nippon Aerosil ■, but almost no images were obtained.

Comparative Example 2 In Example 1, Zaixen A was used as the aqueous resin dispersion.
(Stetsu Seikagaku - Self-emulsifying polyolefin particle size of several microns) was used, but the resin particles were coarse and the capsule coverage was insufficient.

Comparative Example 3 In Example 1, instead of the aqueous resin dispersion, N, N-
Although dimethylol urea was added to insolubilize the residual polyvinyl alcohol, the resistance of the toner was observed to be lower than that of the powder of Comparative Example 1, and almost no images were obtained.

Comparative Example 4 After washing the microcapsules obtained by interfacial polymerization in Example 1, water was removed and the microcapsules were then washed with methanol.

This was made into a dispersion with a solid content of 25% in methanol, and then a methanol solution of ketone-aldehyde resin was prepared.

The solid content was added at a solid content ratio of 3% by weight based on the solid content of the microcapsules.

Next, water was added to this methanol dispersion to precipitate the ketone-aldehyde resin onto the microcapsules.

This dispersion was spray dried. However, when washing microcapsules with methanol, the core component inside the capsule passes through the shell into methanol and dissolves.

Only sticky powders were obtained even by spray drying.

Furthermore, it was confirmed that the resistance was lower than that of Comparative Example 1.

Comparative Example 5 The powder obtained by spray drying in Comparative Example 1 was
(manufactured by Soken Kagaku ■) and spray drying was attempted, but the powder obtained by spray drying in Comparative Example 1 was
-No agglomeration when mixed with the dispersion of 2029.

Spray dryer nozzles frequently clogged.

Example 2 Paraffin wax (SP-0145 Nihon Danro ■) 5 parts Ethylene-vinyl acetate copolymer (30% vinyl acetate) 8 parts Polybutene oil (Nippon Oil LD-10) 20 parts Isopar M 10 parts Toluene 5 parts Magnetic powder (
BL-220 Titanium Industry Side) 40 parts The mixture of the above formulation was dispersed in a three-roll mill to obtain a soft ink-like material. (Ink B) The same treatment as in Example 1 was carried out to obtain a capsule toner coated with hydrophobic resin fine particles from the aqueous resin dispersion.

When 0.3% of colloidal silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) was added and the same printing test as in Example 1 was conducted, a good image without fogging could be obtained.

Further, even when one capsule toner was left in an environment of 30° C. and relative humidity of 70%, there was no decrease in image density that was thought to be caused by moisture absorption.

Example 3 Petroleum resin (DRA-100P manufactured by Toho Oil Resin ■) 2 parts paraffin wax (SP-0145 Nippon Wax @)) 7 parts carnauba wax (Powder 1 Nippon Wax ■)) 55 parts Toluene 30 parts Magnetic powder (MAT305 Toda Kogyo @) 40 parts diisopropylnaphthalene 10 parts The mixture of the above formulation was melted and dispersed in a homodisper.

To 200 parts of the above melted dispersion, heated isocyanate (
After adding 45 parts (same as Example 1) and mixing and dissolving, 8 parts
2% polyvinyl alcohol aqueous solution heated to 0°C 15
After emulsification, 150 parts of a 10% diethylenetriamine aqueous solution was added, and stirring was continued for 3 hours to cause an interfacial polymerization reaction. produced microcapsules.

Thereafter, an aqueous resin dispersion was coated by the same operation as in Example 1. When the same printing test as in Example 1 was carried out, a good image without fogging could be obtained.

Example 4 Synthetic wax (Sunwax 131-P manufactured by Sanyo Chemical) 5 parts Polybutene oil (LV-10 manufactured by Nippon Oil ■) 40 parts Lecithin 2 parts Carbon black (Mogal manufactured by Cabot ■) 2 parts Magnetic powder (BL-220) 40 parts (manufactured by Titan Kogyo ■) A mixture of the above formulation was dispersed in a three-roll mill to obtain a soft ink-like material. (Ink D) 7 parts of terephthaloyl chloride was dissolved in 12 parts of warmed diptyl phthalate, and this liquid was added to the above ink D.
70 parts were mixed.

This mixture was poured into a 2.0% polyvinyl alcohol aqueous solution heated to 70° C., and emulsified by high-speed stirring at 1,010,000 rpm using a homomixer (UH-10 manufactured by Nippon Seiki ■).

To this were added 4 parts of diethylenetriamine and 2 parts of sodium carbonate dissolved in 20 parts of water.

Stirring was performed at low speed for 10 hours to produce capsule particles by interfacial polymerization.

After washing and decanting the emulsion containing the capsules four times, the solid content of the capsules was reduced to approximately 35%, and the aqueous resin dispersion (
ME-3100-220% (manufactured by Soken Kagaku ■) was added at a solid content ratio of 6%, and spray drying was performed.

Colloidal silica (
A printing test similar to that in Example 1 was conducted by adding 0.3% of R-972 (manufactured by Nippon Aerosil ■).

A good image without capri was obtained.

Further, there was no decrease in toner resistance, which is thought to be caused by residual polyvinyl alcohol, and no decrease in density due to poor moisture resistance.

Example 5 A powder toner was obtained in the same manner as in Example 1 except that hexamethylene diamine was used instead of diethylene triamine.

The same effects as in Example 1 could be obtained.

Example 6 Ethylene-vinyl acetate copolymer (same as Example 1) 5 parts synthetic wax (same as Example 1) 5 parts petroleum resin (same as Example 1) 5 parts high boiling point solvent (same as Example 1) ) 20 parts diisopropylnaphthalene 1 (1 magnetic powder (BL
-220 (manufactured by Titanium Industry Co., Ltd.)) 40 parts The mixture of the above formulation was dispersed in a three-roll mill to obtain a soft ink-like material. (Ink E) To 8,320 parts of this ink, 15 parts of toluene, 0.06 parts of dibutyl tin dilaure, and 50 parts of isocyanate (Millionate MR-200 manufactured by Nippon Polyurethane) were added and mixed, and then 0.75% polyvinyl Add 100 parts of an aqueous alcohol solution and stir gently.

This emulsion was added to 1,300 parts of a 0.75% polyvinyl alcohol aqueous solution and emulsified for 3 minutes using a colloid mill at 110,000 rpm to obtain particles with an average particle size of 14 μm.

This emulsion is then heated while stirring at a low speed, and foaming due to the reaction between the isocyanate and water is confirmed. After the emulsion was heated and reacted for 1 hour while foaming, 150 parts of a 10% diethylenetriamine aqueous solution was added to stop the foaming and stirring was continued for 3 hours to form capsules by interfacial polymerization.

After leaving the above capsule dispersion overnight, washing with warm water,
Decantation was repeated four times to adjust the solid content of the capsule to 50%.

The aqueous resin dispersion VE' was added to the dispersion prepared in this way.
-2029 (same as in Example 1) was mixed and dispersed at a solid content ratio of 5%, and dried in a spray dryer at an inlet temperature of 1.
Spray drying was performed at 40°C.

The powder obtained by spray drying has a uniform hydrophobic coating of styrene-methyl methacrylate copolymer resin on the outer surface of the shell formed by interfacial polymerization.

When 0.3% of colloidal silica (R-972 manufactured by Nippon Aerosil ■) was added to the above powder and a printing test similar to that in Example 1 was conducted, a good image without fogging was obtained.

Example 7 In Example 6, the mixed dispersion of the capsule dispersion and the aqueous resin dispersion was not spray-dried, but water was removed by vacuum filtration and dried in a vacuum drier.

The dried aggregates were crushed using a crusher to obtain powder coated with styrene-methyl methacrylate copolymer resin.

An image almost the same as that of Example 6 was obtained, although some particles were partially broken due to the crushing process.

Example 8 Coronate L (
The same test was carried out below, except that Nippon Polyurethane Co., Ltd.) was used.

Example 9 Millionate M instead of the isocyanate of Example 1
The same test was conducted below, except that a 50:50 mixture of R-200 and Coronate L was used.

Example 10 In Example 6, VE-202 was used as the aqueous resin dispersion.
9 and ME-3100-2 (manufactured by Soken Kagaku ■) were added at a solid content ratio of 3%, and the same test was conducted.

Note 1) Toner particles are compressed at 200 kg/aj to form pellets with a diameter of 2.0 am and a thickness of approximately 3 fl.

This is a diameter of 1.5mm with a guard electrode. Qcm main electrode 0
It was sandwiched between two paste pastes, a DC voltage of 100 V was applied, and after the current value stabilized, measurements were taken. Toner suitable for copying on plain paper must have an a1MIfTtNπ value of 1014Ω1 or more according to this measurement method.

〔Effect of the invention〕

According to the present invention, since the toner particles are encapsulated by an interfacial polymerization method, fixing can be easily performed at low pressure.

In addition, capsule particles produced by interfacial polymerization can be processed in the state of an aqueous dispersion, and can be coated without going through a drying process or a crushing process.

In addition, since the aqueous resin dispersion can be used as it is in the state obtained by emulsion polymerization, it is possible to dry it to form fine particles.
It is inexpensive because it does not go through the process of replenishment.

In addition, it is possible to omit the steps of agglomeration and crushing of fine particles that occur during powdering to obtain fine resin particles from an aqueous resin dispersion, and therefore it is easy to uniformly adhere them to the surface of the capsule.

Furthermore, after drying, the above aqueous resin dispersion forms a high-resistance coating with good moisture resistance on the surface of the capsule, so that residual dispersion stabilizers used in the emulsification of the core material remain on the surface of the capsule. However, it can be a toner with good moisture resistance.

Claims (1)

[Claims] 1. A core material having pressure fixing properties is encapsulated in a shell formed by interfacial polymerization, and then mixed with an aqueous resin dispersion, and the above-mentioned aqueous resin is applied to the outer surface of the capsule. A powder toner characterized in that a resin in a resin dispersion is adhered to cover capsules. 2. The powder toner according to claim 1, wherein the aqueous resin dispersion is obtained by soap-free emulsion polymerization. 3. The powder toner according to claim 1, wherein the aqueous resin dispersion comprises spherical particles having a particle size of 0.01 to 1 μm. 4. The powder toner according to claim 1, which uses two or more kinds of aqueous resin dispersions.