JPS58182644A - Preparation of encapsulated toner - Google Patents

Abstract

PURPOSE:To form an encapsulated toner improved in powder characteristics, especially, agglomeration resistance, and offset resistance, and adapted to use for a pressure fixing system, by spray-drying a liquid dispersion of the encapsulated toner, and subjecting it to heat treatment. CONSTITUTION:Acid chloride and polyisocyanate are dissolved into a hydrophobic liquid contg. core materials of a display recording material, e.g., a colorant, such as carbon black, a binder, such as phthalic ester, and magnetic powder, etc., and then, this liquid mixture is dispersed into an aq. dispersion medium contg. polyamine and a dispersing agent. The obtained liqid dispersion is adjusted in pH to weak alkalinity, and heated to 40-90 deg.C to form microcapsules having double shells consisting of a polyurea resin inside layer and a polyamide resin outside layer. Then, they are separated and spray dried, heat treated at 50-300 deg.C for 10min-48hr, and then when needed, a minute amt. of fludizing agent is attached to the surfaces to obtain an encapsulated toner product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner used for converting a latent image formed in an electric or magnetic recording method such as electrophotography or magnetic recording method into a visible image. . More specifically, the present invention relates to a method for producing capsule toner used for these applications.

As electrical or magnetic recording methods, various methods called electrophotography, electrostatic recording, or magnetic recording are known, and many of these methods are known. What these methods have in common is that a latent image formed electrically or magnetically is converted into a visible image using a toner containing a display recording material such as a colorant in the form of a powder or dispersion, and this is transferred to a transfer paper. Transfer and fix onto a medium such as ? This is the point of making it an MV image.

In order to turn a latent image into a visible image using toner, electricity is generally applied between a developer consisting of carrier particles and toner, or a developer consisting only of toner, and the latent image. A method is used in which a toner image is formed on the latent image by attracting toner to the latent image using a target or magnetic attraction force, and the latent image is developed into a visible image. Here, the former development method using a developer consisting of carrier particles and toner is called a two-component development method, and the latter development method using a developer consisting only of toner is called a one-component development method. ing.

The toner image formed in the latent image is then transferred onto a medium, such as transfer paper, and fixed onto the medium. There are three known methods for fixing toner images on media such as transfer paper: heat fixing, solvent fixing, and pressure fixing. The present invention provides a method for manufacturing.

A pressure fixing method for fixing toner particles onto a medium by applying pressure to the toner particles transferred to the medium-1 is described in US Pat. No. 3,289,528. Since this method does not use heat or solvent, it does not have the various problems associated with methods such as heat fixing or solvent fixing, and has a fast access time, making it compatible with high-speed fixing methods. It inherently has various advantages.

However, the pressure fixing method has poor fixing properties compared to fixing methods such as heat fixing, the fixed image is easily peeled off when rubbed, and it requires considerably high pressure for fixing, so it cannot be used with media such as transfer paper. Fatigue of the media is likely to occur due to destruction of the fibers of the media, the surface of the media is likely to become too shiny, and there are limits to miniaturization of the pressure rollers used to apply high pressure. Therefore, there are problems in that miniaturization of the entire copying apparatus is restricted.

In order to solve the above-mentioned problems associated with the pressure fixing method, capsule toner in which toner is contained in microcapsules has already been developed. Capsule toner is a toner in the form of microcapsules obtained by forming an outer shell around a core material containing a display/recording material such as carbon black, which has the property of being destroyed by the application of pressure. Capsule toner is said to be a toner suitable for the pressure fixing method because it does not require high pressure for fixing and has excellent fixing properties. This cannot necessarily be said to be satisfactory for the various properties that are originally needed.

That is, for example, a toner used as a developer for dry electrophotography is required to have good powder characteristics, excellent developing performance, and not to stain the surface of the photoreceptor, which is the surface on which a latent image is formed. Furthermore, in the case of a two-component development method, it is necessary that the surface of the carrier particles used is not contaminated. In addition, the toner used in the pressure fixing method has good pressure fixing properties and is unlikely to cause offset phenomenon (a phenomenon in which toner adheres to the pressure roller surface and stains it) on the pressure roller used for pressure fixing. It becomes necessary.

However, the capsule toners known so far have not always been satisfactory in terms of the above-mentioned properties.

Among these objects, the first object of the present invention is to provide a method for producing a capsule toner with particularly improved powder characteristics. Here, the powder property means the non-cohesiveness of the toner powder. That is, in the production of conventional capsule toner, methods such as spray drying are usually used to separate and dry the capsule toner from the capsule toner dispersion, but in the first step of this spray drying, or There was a tendency for aggregation to occur between a plurality of capsules during storage and storage after spray drying, resulting in a so-called "stank" state. and,
The capsule toner in this "stank" state significantly reduces the resolution of the visible image formed on the latent image, and therefore the sharpness of the resulting copied image. This becomes a major obstacle to obtaining clear copied images.

The inferior powder properties of conventional capsule toners have been one of the reasons for preventing the practical use of pressure fixing methods using capsule toners.

Another object of the present invention is to provide a method for producing a capsule toner having excellent powder properties and pressure fixing properties, and improved offset properties.

Furthermore, the present invention has excellent powder characteristics and pressure fixing properties, improved offset properties, and has excellent resistance such that it does not break due to impact in the developing device but easily breaks only at the pressure fixing position. It is also an object to provide a method for producing capsule toners exhibiting impact properties.

According to the research of the present inventor, the object of the present invention as described above is to provide a capsule toner having a double layer outer shell consisting of a layer mainly composed of a polyurethane resin or a polyurea resin and a layer mainly composed of a polyamide resin. It has been found that this can be particularly effectively achieved by separating and drying the capsule toner from the dispersion using a spray drying method, and then adding a step of further subjecting the capsule toner to a heat treatment.

That is, according to the research of the present inventor, capsule toner (
Microcapsule) b) When the dispersion is subjected to a spray drying process, the microcapsules may partially break or cleave, which may expose part of the core binder to the outside of the microcapsules, or the capsule toner may It turns out that this is the main cause of "mamako". Therefore, in the present invention, spray-dried microcapsules are subjected to heat treatment t, Z,! = 4. Therefore, it is thought that the occurrence of "Mamako J" is almost no longer observed because the binder that has been misted outside is removed or its viscosity is reduced.However, in addition to the above reasons, for example, Various factors are thought to be involved, such as a reduction in the occurrence of "mamako" due to changes in the physical and chemical properties of the capsule shell due to heat treatment of microcapsules after spray drying. It is estimated that various factors will also have a positive impact.

Therefore, the present invention provides a double-layered outer layer consisting of a layer containing a polyurethane resin or polyurea resin as a main component and a layer containing a polyamide resin as a main component around a core substance containing a display recording material and a binder in an aqueous medium. This method consists of preparing microcapsules by forming shells, then spray-drying a dispersion containing the microcapsules, and then subjecting it to heat treatment.

Next, the present invention will be explained in detail.

An example of a method for producing microcapsules that can be used in the present invention is the interfacial polymerization method shown below.

Acid chloride (substance A) and polyisocyanate-1 (substance B) are dissolved in a hydrophobic liquid consisting of a display recording material and a binder, or if necessary a core substance such as magnetic powder, and this is dissolved in a polyamine (substance C). A dispersion liquid is prepared by dispersing it into fine droplets in an aqueous medium containing a dispersant and a dispersant.

When an alkaline substance is added so that the pH of the dispersion becomes neutral or slightly alkaline, a polyamide resin wall, which is a reaction product of acid chloride and polyamine, is formed at the aqueous liquid/aqueous medium interface. After that, the dispersion was heated at 40-90°C.
When heated to a range of , a wall consisting of polyurea resin, which is a reaction product of polyisocyanate and polyamine, is formed from the inside, an outer layer consisting of polyamide resin, and
Microcapsules are obtained which have a double-layer shell, the inner layer of which is a polyurea resin.

In addition, if a polyol (substance D) is further added to the hydrophobic liquid and the above treatment is performed, it is possible to have a polyamide resin layer on the outside and a polyurea resin layer made of a reaction product of polyisocyanate and polyamine on the inside. A double-layer shell capsule is obtained having a layer consisting of a polyurethane resin, a reaction product of a resin and/or a polyincyanate and a polyol.

Furthermore, by adjusting the amount of polyamine added to the hydrophobic liquid to an amount that has an equivalent relationship with acid chloride, a double-layer outer shell capsule in which the inner layer is substantially formed only from a polyurethane resin layer can be obtained. You can also do that.

In addition, in the present invention, the expressions polyamide resin, polyurea resin, and polyurethane resin do not necessarily mean resins having only bonding groups of amide bonds, urea bonds, and urethane bonds. Polyurethane resins also include resins in which a portion of the bonding groups are replaced by urea bonds, and the same applies to other resins.

In addition, the outer shell formed by the above method has a double layer outer shell as its basic structure, but this double layer does not necessarily have to have a clear boundary surface. It is sufficient that the outer surface and its vicinity are formed substantially of a polyamide layer, while the inner surface of the shell and its vicinity are formed substantially of a polyurea resin, a polyurethane resin, or a mixture thereof.

The core material obtained in this way (display recording material and binder,
After separating and removing the reaction medium from the double-layer shell capsule containing (or magnetic powder, etc.), the capsule is dispersed in a new aqueous solvent and spray-dried by a known method.
A capsule toner having a suitably robust outer shell and good powder characteristics can be obtained. However, in the present invention, in order to produce a capsule toner exhibiting even better powder properties, a step is added in which the capsule toner powder obtained by spray drying is further subjected to heat treatment.

That is, in the present invention, the microcapsules spray-dried by the above method are then subjected to heat treatment. The heat treatment is preferably carried out at a temperature in the range of 50-300°C, and 80-80°C. It is particularly preferred to heat at a temperature in the range of 15 (1), the heating time varies depending on the heating temperature and the type of binder used, but is usually selected from 10 minutes to 48 hours, more generally 2 - Selected from the range of 24 hours.

There are no particular restrictions on the equipment and equipment used for heat treatment, and examples include any heating, thermal drying equipment, and thermal drying such as electric furnaces, Matsufuru furnaces, photoplates, electric dryers, fluidized bed dryers, infrared dryers, etc. Instruments can be used.

Furthermore, on the surface of the heat-treated capsule toner,
It is preferable to attach a small amount of fluidizing agent by a method such as addition and mixing, and by such an operation, a capsule toner with extremely excellent powder characteristics (for example, a very smooth surface) can be obtained. be able to. Here, what is generally called a lubricant is used as the fluidizing agent, and for example, a small amount of fine particulate powder such as silica, talc, metal salts of higher fatty acids, aluminum silicate, and magnesium fermentation can be added. It is valid.

Next, examples of materials A, B, C, and D used for forming the double shell of the capsule toner of the present invention will be described.

Substance A is an acid chloride, examples of which are adipoyl chloride, sebacoyl chloride, phthaloyl chloride, isophthaloyl chloride, tere-2-thaloyl chloride, fumaroyl chloride, and 1,4-cyclohexane dicarbonyl chloride. , 4,4'-biphecol diluponyl chloride, phosgene, 4,4'-sulfonyldibenzoyl chloride 1, polyesters having acid chloride functional groups, polyamides having acid chloride functional groups, and the like.

B Substance Bine is a polyinsyanate having two or more cyanate groups, examples of which include m-phenylene diisocyanate, p-phenylene diisocyanate, 2.
6-) lylene diisocyanate, 2.4-) lylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3
, 3'-dimethoxy4.4'-biphenyl diisocyanate, 3.3'-dimethyldiphenylmethane-4
, 4'-diisocyanate, xylylene-1,4-diincyanate, xylylene-1,3-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene -1,2-diisocyanate, butylene-1,2-diisocyanate, ethyridine diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate,
4,4',4''+triisocyanates such as triphenylmethane triisocyanate, toluene-2,4,8-)lisocyanate, polymethylene polyphenylisocyanate, 4,4'-dimethyldiphenylmethane, 2 .2', 5.5'-Tetraisocyanates such as tetraisocyanates, adducts of hexamethylene diisocyanate and bexanetriol, 2.4
- polyisocyanate prepolymers such as adducts of tolylene diisocyanate and prenz catechol, adducts of tolylene diisocyanate and hexanetriol, adducts of tolylene diisocyanate and trimethylolpropane, etc. be able to.

Substance C is a polyamine, and examples thereof include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, piperazine, 2-methylbiperazine, 2.5- dimethylpiperazine, 2-hydroxytrimethylenediamine,
Examples include diethylenetriamine, triethylenetetraamine, diethylaminopropylamine, tetraethylenepentamine, and amine adducts of epoxy compounds.

Substance D is a polyol, examples of which are i, ethylene glycol, 1,4-butanediol, catechol, resorcinol, hydroquinone, 1,2-dihydro9
x-4-methylbenzene, l,3-dihydroxy-5
-Methylbenzene, 3.4-dihydroxy-l-methylbenzene, 3.5-dihydroxy-1-methylbenzene, 2゜4-dihydroxyethylbenzene, 1,3-naphthalenediol, 1,5-naphthalenediol, 2.7
-naphthalene diol, 2,3-naphthalene diol, and the like.

Preferable combinations of the above substances A and C for forming the polyamide resin include tylphthalic acid chloride and hexamethylene diamine, sebacoyl chloride and hexamethylene diamine, terephthalic acid chloride and p-phenylene diamine, Examples include terephthalic acid chloride and triethylenetetraamine, and a capsule toner in which a polyamide resin formed by a combination of these constitutes the outer surface of the double layer shell exhibits particularly excellent powder properties.

In the present invention, when a hydrophobic liquid consisting of substance A, substance B, core substance, etc. is dispersed into microdroplets in an aqueous medium containing substance C (or further D), the hydrophobic It is preferable to mix a low boiling point solvent or a polar solvent with the liquid.

These low boiling point solvents or polar solvents contribute to promoting shell formation. Examples of low-boiling or polar solvents that can be used for such purposes include methyl alcohol, ethyl alcohol, ethyl ether, tetrahydrofuran, dioxane, methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, -Pentane, n-hexane, benzene, petroleum ether, chloroform, carbon tetrachloride, methylene chloride, ethylene chloride, carbon disulfide, dimethylformamide and the like.

The core material used in the present invention contains a display recording material for converting a latent image into a visible image.
Usually, a coloring agent that provides a visible image in its state is used, but a substance that indirectly provides a visible image, such as a fluorescent material, can also be used.

As the coloring agent, dyes and pigments conventionally used in dry or wet toners can be used.8 For example, as a black toner, carbon black or grafted carbon black can be used. Examples of chromatic colorants include blue colorants such as copper phthalocyanine and sulfonamide derivative dyes, yellow colorants such as benzidine derivatives collectively known as diazoyero, and polytungstophosphoric acid and molybdenum Examples include rhodamine B lake, which is a double salt of acid and xanthine dye, carmine 6B, which is an azo pigment, and red coloring agents such as quinacridone derivatives.

The binder used in the present invention disperses and holds the display recording material in the core material, and when transferring the visible image made of the display recording material formed on the latent image to a medium such as copy paper. It functions to fix the image on the medium. Therefore, binders are conventionally used when oil-soluble photographic additives are finely dispersed in an aqueous medium and incorporated into silver halide color light-sensitive materials, or highly It is preferable to use a boiling point organic solvent or a polymer that has been used or studied as a binder for inclusion in the core material of pressure-fixable capsule toners.

Examples of such high boiling point organic solvents include the following compounds.

(1) Phthalate esters dibutyl phthalate, dioctyl phthalate, dioctyl phthalate, dioctyl phthalate, dinonyl phthalate, didecyl phthalate, butyl phthalyl butyl glycolate, dibutyl monochloro phthalate.

(2) Phosphate esters tricresyl phosphate, trioctyl phosphate, tris(isopropylphenyl) phosphate, tributyl phosphate, trihexyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, trioleyl phosphate, tris( butoxyethyl) phosphate, tris(chloroethyl) phosphate, tris(dichloropropyl) phosphate.

(3) Citric acid esters 0-acetyl triethyl citrate, 0-acetyl tributyl citrate, 0-acetyl trihexyl citrate, 0-acetyl trioctyl citrate, 0-acetyl trinonyl citrate, 0-acetyl tride Sil citrate, triethyl citrate, tributyl citrate, trihexyl citrate, trioctyl citrate,
Trinonyl citrate, tridecyl citrate.

(4) Benzoic acid esters butyl benzoate, hexyl benzoate, heptyl benzoate, octyl benzoate, nonyl benzoate, decyl benzoate, to-F” syl benzoate, tridecyl benzoate, tetradecyl benzoate, hexadecyl benzoate, octadecyl benzoate, oleyl benzoate, Pentyl 0-methylbenzoate, Decyl p-methylbenzoate, Octyl 0-chlorobenzoate, Lauryl p-chlorobenzoate, Propyl 2,4-dichlorobenzoate, Octyl 2,4-dichlorobenzoate, Stearyl 2,4-
Dichlorobenzoate, oleyl 2°4-dichlorobenzoate, octyl p-methoxybenzoate.

(5) Fatty acid esters hexadecyl myristate, dibutoxyethyl succinate, dioctyl adipate, dioctyl azelate,
Decamethylene-1,10-diol diacetate, triacetin, tributin, benzyl caprate, pentaerythritol tetracapronate, isosorbite cycloacrylate.

(6) Alkylnaphthalenes methylnaphthalene, dimethylnaphthalene, trimethylnaphthalene, monoisopropylnaphthalene, diisopropylnaphthalene, triisopropylnaphthalene, tetrainpropylnaphthalene, monomethyldiethylnaphthalene, inoctylnaphthalene.

(7) Alkyldiphenyl ethers 0-methyldiphenyl ether, m-methyldiphenyl ether, p-methyldiphenyl ether.

(8) Amide compounds of higher fatty acids or aromatic sulfonic acids N,N-dimethyllauramide, N,N-diethylcaprylamide, N,N-butylbenzenesulfonamide.

(9) Trimellitic acid esters trioctyl trimellitate.

(10) Diarylalkanes Diarylmethanes (dimethylphenylphenylmethane), diarylethanes (1-phenyl7.1-methylphenylethane, 1-dimethylphenyl-1-phenylethane, 1-ethylphenyl-1-phenylethane) ).

Furthermore, examples of the above-mentioned high-boiling point organic solvents and other high-boiling point organic solvents that can be used in the present invention are described, for example, in the following patent publications.

Special Publication No. 4B-23233, No. 49-284fi1:
JP-A-47-4031, JP-A No. 50-82832, JP-A No. 5
No. 0-82078, No. 51-28035, No. 51-2
No. 6036, 5I-2f (No. 037, 51-279
No. 21, No. 51-27922: U.S. Patent No. 2,322
, No. 027, No. 2,353,282, No. 2,53
No. 3,514, No. 2,835,579, No. 2,8
52, No. 38'3, No. 3,287,134, No. 3,554,755, No. 3. El? No. 8,137,
Same No. 3,137 El, No. 142, Same No. 3゜700.45
No. 4, No. 3,748,141, No. 3,837.8
H, No. 3,938,303: British Patent No. 958,441, No. 1.222.753
No. 1.34J3134: OLS No. 2,538,889.

Examples of preferable polymer compounds that can be used in the present invention include the following compounds. However, when these polymers used in the present invention are used alone, it is desirable that they have a low molecular weight.

Polyoleguin, olefin copolymer, styrene resin, epoxy resin, polyester, rubber, polyvinylpyrrolidone, polyamide, coumaron-indene copolymer,
Methyl vinyl ether/maleic anhydride copolymer, maleic acid-modified phenolic resin, phenol-modified terpene resin, silicone resin, epoxy-modified phenolic resin, natural resin-modified phenolic resin, amino resin, polyurethane,
Polyurea, acrylic acid and long chain alkyl methacrylate'-
Copolymer oligomer with polyvinyl acetate and polyvinyl chloride.

Further, examples of the above-mentioned polymers and other polymers that can be used in the present invention are described in, for example, the following patent publications.

Japanese Patent Publication No. 413-15f18, No. 54-8104: Japanese Patent Publication No. 48-75032, No. 4B-78i1131,
No. 49-17739, No. 51-132838, No. 5
No. 2-88531, No. 52-108134, No. 52-
No. 11111137, No. 53-1028, No. 53-3
No. 8243, No. 53-1180411, No. 55-B
No. F3854, No. 55-188655: U.S. Patent No. 3.8H,833.

In the present invention, the binder may be one of the various high-boiling organic solvents or polymers mentioned above, or may be a mixture of arbitrary compounds.

In order to obtain favorable fixing properties, it is particularly advantageous to use a mixture of a high-boiling organic solvent and a polymer as the binder.

The core material of the capsule toner produced according to the present invention contains the display recording material and the binder as described above, but it can also contain various additives if desired. Examples of such additives include mold release agents such as fluorocarbon resins, and toners used in -component development systems. Examples include magnetic particles made of simple metals, alloys, or metal compounds such as cobalt, iron, and nickel.

In the present invention, the aqueous medium used in Stingray V to form microcapsules is water alone, or a mixture of water and a substance that is compatible or soluble in water. In addition, it is desirable to add a dispersant to the aqueous medium as described above.The dispersant has the function of emulsifying and dispersing a hydrophobic liquid into microdroplets in the aqueous medium. Colloids or surfactants are commonly used. Examples of hydrophilic protective colloids include:
Gelatin, graft polymers of gelatin and other polymeric substances, derivative gelatin and cellulose produced by the reaction of gelatin with compounds such as acid anhydrides (maleic anhydride, phthalic anhydride, etc.), isocyanates, compounds containing active halogen atoms, etc. Examples include natural substances such as derivatives and sugar derivatives, derivatives thereof, and hydrophilic synthetic polymer substances such as polyvinyl alcohol.

As described above, the dispersion containing the microcapsules formed by the double layer shell forming reaction is prepared by separating and removing the reaction medium, dispersing the microcapsules in a new aqueous solvent, and subjecting the dispersion to a known spray drying operation. By drying it, it becomes dry microcapsules (capsule toner).

In addition, before dispersing the microcapsules in a new aqueous solvent, it is desirable to include a step of washing the capsules using a nonionic or cationic surfactant aqueous solution. The powder characteristics of the resulting capsule toner are further improved by washing with a water filter. In addition, the aqueous solvent that functions as a dispersion medium for microcapsules during spray drying may be simple water, but it may also be an aqueous solvent to which compounds such as metal soaps, succinate ester surfactants, or organic fluoro compounds have been added. It is preferable that By spray-drying a microcapsule-containing dispersion containing such compounds, these compounds adhere to the surface of the capsule toner and contribute to improving the powder properties of the resulting capsule toner.

Examples of metal soaps include calcium dioleate, calcium diisostearate, and monostearate.

Examples of the succinic acid ester-based surfactants include sulfosuccinic acid bistridecyl ester sodium salt, sulfosuccinic acid phenethyl octyl ester sodium salt, sulfosuccinic acid di-2-ethylhexyl ester sodium salt, sulfosuccinic acid di-2-ethylhexyl ester sodium salt, and sulfosuccinic acid diisohexyl ester sodium salt. be able to.

Examples of organic fluoro compounds include compounds represented by the following chemical formula.

CF a (CF 2 ) e COON HaCl
(CF2'-CF,)a C00NaH-(CF
CJL-CF2)s C00HCF3- (CF2)
s (OCOCHs)2 In addition, in order to impart high conductivity to the surface of the capsule toner, carbonaceous fine powder such as carbon black and graphite, metal fine powder, zinc oxide, It is also possible to use a method of adding fine powder of a white metal oxide such as titanium oxide or antimony-doped tin oxide.

On the other hand, the outer shell of the capsule toner produced according to the present invention is made of a polymer or high molecular material, and if desired, this outer shell may also be coated with a metal-containing dye, a charge control agent such as nigrosine, or hydrophobic silica. Glidants such as or other additives may be added. These additive substances can be incorporated into the outer shell of the capsule toner at any time, such as during shell formation, after spray drying of the capsule toner, or after heat treatment according to the present invention. Among these, the capsule toner obtained according to the present invention with a fluidizing agent such as particulate hydrophobic silica attached to the surface has particularly excellent powder properties and is not easily resistant to high temperatures and high humidity (for example, at a temperature of 50 Even if it is stored for several days at a temperature of 90% relative humidity, it does not cause phenomena such as blocking.

As described above, the capsule toner obtained by manufacturing a capsule toner having a specific double-layer outer shell according to the present invention, spray drying it, and then subjecting it to heat treatment has very excellent powder properties. However, it also exhibits excellent properties in terms of impact strength, fixing properties, anti-offset properties, etc., which are problems in practical use as capsule toners.

Next, examples of the present invention will be shown. In each example, "parts" indicate "parts by weight" unless otherwise specified.

[Example 1] 4 parts of carbon black was added to 46 parts of castor oil and mixed thoroughly to obtain a primary liquid.

Separately, a secondary liquid was prepared by dissolving in 25 parts of ethyl acetate 25 parts of an adduct of toluylene diisocyanate and hexanetriol (manufactured by Desmodour, Bayer AG) and 2 parts of terephthalic acid chloride.

200 parts of a 10% aqueous gum arabic solution was previously discarded, and a mixture of a secondary liquid and a secondary liquid was emulsified and dispersed therein to obtain a water-in-oil emulsion having an average oil droplet diameter of 10 liters.

To this emulsion was added 10 parts of a 10% aqueous solution of hekisai methylenediamine, and after stirring for 30 minutes, the pH was adjusted to 9.
．． A 10% aqueous sodium carbonate solution was added to the sea urchin. After heating the mixture to 70°C for 2 hours under stirring [
The reaction was carried out.

The microcapsule dispersion thus obtained was washed with water three times using centrifugal releasability, and then spray-dried using a spray dryer (manufactured by Yamato Kagaku Co., Ltd.) to form a powder capsule toner (
Boria, the reaction product of tereditalic acid chloride and l-xamethylene diamine.

It has a double-layer outer shell composed of an outer layer made of polyurea resin and an inner layer made of polyurea seven resin, which is a reaction product of toluylene diisosifnate and hexanetriol and hex→methylene diamine. ．． A capsule toner containing carbon black and castor oil was obtained.

The capsule toner described in I- is heated using an infrared dryer.
Heat treatment was performed at 100℃ for 24 hours, and the )F
・The characteristics of one body were investigated. Capsule toner after heat treatment is
It was a very smooth powder, and microscopic observation confirmed that each capsule particle was individually stacked. Further, this capsule toner did not cause phenomena such as blocking even when stored for one day at high temperature and high humidity (temperature 50'0, relative humidity 90%).

1 Next, hydrophobic silica (Aerosil-R manufactured by Nihon Aerosil Hayashi Co., Ltd.) was added to the heat-treated capsule toner.
-972) was added in an amount of 0.5% by weight, a capsule toner with further improved fluidity was obtained.

Even when the oral capsule toner was stored at high temperature and high humidity (temperature 50°C, relative humidity 90%) for several days, phenomena such as blocking did not occur.

4 Next, the pressure fixing characteristics of the capsule toner containing hydrophobic silica were evaluated by the following method.

A developer was prepared by thoroughly mixing 5 parts by weight of capsule toner and 95 parts by weight of iron powder carrier using a shaker. When the state of the capsule toner after mixing with the carrier was similarly observed under a microscope, no broken capsules were found.

An electrostatic latent image formed by a conventional electrophotographic method was developed with a developer as described above to form a toner image, and the toner image was transferred to transfer paper to obtain a visible image. When this visible image was pressure-fixed using a pressure fixing roller at a pressure of 350 kg/cm', a copied image with good fixability and high sharpness was obtained. In addition, almost no toner adhered to the roller.

[Example 2] Desmodur L was added to 25 parts of ethyl acetate as a secondary liquid.
Microcapsule manufacturing reaction and spray drying were carried out in the same manner as in Example 1, except that a solution of 25 parts of terephthalic acid chloride, 2 parts of terephthalic acid chloride, and 1 part of azocadrol (manufactured by Asahi Denka ■, a propylene oxide adduct of ethylenediamine) was used. Powdered capsule toner (outer layer consisting of a polyamide resin of the reaction product of tereditalic acid chloride and propylene oxide di-I adduct of ethylenediamine, and addition of toluylene diisocyanate and hexanetriol) The capsule toner has a double-layered outer shell composed of an inner layer made of Bourea resin/polyurethane resin, which is a reaction product of a propylene oxide adduct of ethylene diamine, and contains carbon bra, 7-ri and castor oil. Obtained.

1. Use an infrared dryer to dry the capsule toner described below for 10 minutes.
Heat treatment was performed at 0'C for 24 hours, and the powder properties were investigated. The capsule toner after the heat treatment was a very smooth powder, and microscopic observation confirmed that each capsule particle existed independently. In addition, this capsule toner has high temperature and high humidity (temperature 50
No phenomena such as blocking occurred even after storage for one day at 'O1 relative humidity 90%).

Next, 0% of hydrophobic silica (Aerosil-R-972) was added to the heat-treated capsule toner.

When 5% of Toto was added, a capsule toner with further improved fluidity was obtained. This capsule toner has high temperature and high humidity (
Even when stored at several liters at a temperature of 50° C. and a relative humidity of 90%, phenomena such as blocking did not occur.

Next, the pressure fixing properties of the capsule toner to which hydrophobic silica was added were prepared in the form of a developer mixed with an iron powder carrier by the method described in Example 1, and evaluated. When the state of the capsule toner after mixing with the iron powder carrier was similarly observed using an ms mirror, no broken capsules were found.

An electrostatic latent image formed by a conventional electrophotographic method was developed with the above developer to form a toner image, and the toner image was transferred to transfer paper to obtain a visible image. When this visible image was fixed under pressure using a pressure fixing roller at a pressure of 350 kg/cm', a copied image with good fixability and high sharpness was obtained. In addition, almost no toner adhered to the roller.

Claims (1)

[Claims] ■. Forming, in an aqueous medium, around a core material containing a display recording material and a binder, a double layer outer shell consisting of a layer mainly composed of a polyurethane resin or polyurea resin and a layer mainly composed of a polyamide resin. 1. A method for producing a capsule toner, which comprises preparing microcapsules, spray-drying a dispersion containing the microcapsules, and then subjecting the dispersion to a heat treatment. 2. The method for producing a capsule toner according to claim 1, wherein the temperature of the heat treatment applied to the 2° spray-dried microcapsules is in the range of 50 to 300°C.