JPH0534664B2 - - Google Patents

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 capsule toners used for these applications.

Various electrical or magnetic recording methods are known, such as electrophotography, electrostatic recording, or magnetic recording. What they 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 or other material. The image is transferred and fixed onto a support medium to form a copied image.

In order to turn a latent image into a visible image using toner, generally a developer consisting of carrier particles and toner, or a developer consisting only of toner,
A method is used in which toner is attracted to the latent image by an electric or magnetic attraction force acting between the latent image and the latent image, and a toner image is formed on the latent image to develop the latent image and make it a visible image. There is. 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. There is.

The toner image formed on the latent image is then transferred onto a medium, such as transfer paper, and fused 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. This is what we provide.

A pressure fusing method in which toner particles are fused onto a medium by applying pressure to the toner particles transferred onto the medium is described in US Pat. No. 3,269,526. Since this method does not use heat or solvent, it does not suffer from the various problems associated with methods such as heat fixing or solvent fixing, and the access time is fast, making it compatible with high-speed fixing methods. It has various inherent advantages.

However, the pressure fixing method has poor fixing properties compared to fixing methods such as heat fixing, and the fixed image easily peels off when rubbed, and requires considerably high pressure for fixing, so it is difficult to use a support like transfer paper. Fatigue of the media tends to occur due to destruction of media fibers, the surface of the supporting media tends to become excessively glossy, and the pressure rollers used to apply high pressure need to be miniaturized. Due to the limitations, there are various problems such as the fact 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. However, it cannot be said that the properties that are originally required are necessarily satisfactory.

In other words, the toner used as an electrophotographic developer has good powder properties and excellent development performance.
It is necessary that the surface of the photoreceptor, which is the surface on which the latent image is formed, should not be contaminated, and in the case of two-component development, it is also necessary that the surface of the carrier particles used should not be contaminated. be done. 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. In other words, the toner used in the pressure fixing method has powder properties, fixability to support media such as paper (including shelf life of the fixed image), non-offset properties, and chargeability and chargeability depending on the developing method used. All properties such as conductivity and/or conductivity must be at a high level. However, hitherto known capsule toners have not always been satisfactory in terms of the above-mentioned properties.

For example, a typical manufacturing method for capsule toner is to prepare microcapsules by forming an outer shell made of a resin material around a hydrophobic core material containing a display recording material dispersed as microdroplets in an aqueous medium. A known method is to use a drying method such as spray drying to obtain a powdery capsule toner from this microcapsule dispersion.

However, perhaps because the capsule toner obtained by the above manufacturing method goes through an aqueous system,
It has a low electrical resistance, and when electrophotography is carried out using it as a developer, problems of poor development and/or poor transfer often occur in the development and transfer steps.

In addition, since the electrical resistance and charge properties of the capsule toner described above are highly temperature dependent, when used in electrophotography, the images obtained are easily affected by environmental conditions such as temperature and humidity, and stable images cannot be obtained. The problem was that it was difficult to obtain.

Alternatively, after drying, the capsule toner may form agglomerates due to secondary aggregation of many capsule particles, or even if it is in a powder state immediately after drying, it must be placed in a high humidity or high temperature environment, or exposed to air. If left for a long time at room temperature, it tends to agglomerate. Furthermore, aggregation of capsule toner often occurs during the developing process in an actual developing device, and in such a case, problems such as a significant decrease in resolution of the developed visible image occur.

Therefore, it is an object of the present invention to provide a capsule toner whose electrical resistance and chargeability are not easily affected by environmental conditions such as temperature and humidity, and which enables the formation of clear images even under normal fluctuations in environmental conditions. It is about providing.

It is also an object of the present invention to provide a capsule toner with excellent powder characteristics. moreover,
It is also an object of the present invention to provide a capsule toner with less offset.

The present invention provides a capsule toner comprising a core material containing a liquid binder and a display recording material and an outer shell formed around the core material,
The capsule toner is characterized in that fluororesin particles are attached to or contained on the surface of the outer shell.

Next, the present invention will be explained in detail.

A method for preparing microcapsules by forming an outer shell around a core material containing a display recording material and a liquid binder that is an aid for fusing the display recording material to a support medium in a liquid medium such as water. are already known, and these known methods can also be used to produce the capsule toner of the present invention.

For example, as a method for producing microcapsules that can be used to produce the capsule toner of the present invention, an interfacial polymerization method can be mentioned.

Examples of other methods for producing microcapsules that can be used to produce the capsule toner of the present invention include an internal polymerization method, a phase separation method, an external polymerization method, a melt dispersion cooling method, and a coacelvation method. can.

Note that the method for manufacturing microcapsules that can be used to manufacture the capsule toner of the present invention is not limited to those exemplified above, and other methods for manufacturing microcapsules can also be used. Moreover, these various methods can also be used in combination.

Among examples of methods for producing microcapsules, a preferred method for the present invention is an interfacial polymerization method.
Among these, the following method is particularly preferable.

First, substances A and B having the following properties are prepared.

Substance A: A hydrophobic liquid itself, or a substance that dissolves or disperses well in a hydrophobic liquid.

Substance B: A substance that is either a hydrophilic liquid itself or has the property of dissolving or dispersing well in a hydrophilic liquid.

The A substance and the B substance react with each other and are insoluble in both hydrophilic liquid and hydrophobic liquid, such as polyurethane resin, polyamide resin, polyester resin, polysulfonamide resin, polyurea resin,
It is a substance that forms epoxy resin, polysulfanate resin, or polycarbonate resin.

Next, a hydrophobic liquid consisting of substance A and a core substance (display recording material, binder, powdered magnetic substance, etc. if desired) is mixed with substance B and a protective colloid forming material (hydrophilic polymer compound, surfactant, etc.). A hydrophobic liquid consisting of substance A and a core substance is produced by dispersing it into microdroplets in the contained hydrophilic liquid and then heating it to cause the two to react at the interface. an outer shell made of polyurethane resin, polyamide resin, polyester resin, polysulfonamide resin, polyurea resin, epoxy resin, polysulfanate resin, or polycarbonate resin that is insoluble in both hydrophilic and hydrophobic liquids. to prepare a dispersion in which microcapsules containing a core substance are dispersed.

In the present invention, a particularly preferred combination of substance A and substance B is such that a polyurethane resin or polyurea resin is formed by the reaction of both substances.

Examples of substances A suitable for producing such polyurethane resins or polyurea resins include the following compounds containing isocyanate groups or isothiocyanate groups.

(1) Diisocyanate m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate,
3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,
4-diisocyanate, 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, tolylene diisocyanate, triphenylmethane diisocyanate.

(2) Triisocyanate 4,4',4''-triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate.

(3) Tetraisocyanate 4,4'-dimethyldiphenylmethane-2,2',
5,5'-Tetraisocyanate.

(4) Polyisocyanate prepolymer Adduct of hexamethylene diisocyanate and hexanetriol, adduct of 2,4-tolylene diisocyanate and catechol, adduct of tolylene diisocyanate and hexanetriol, tolylene diisocyanate and Adduct of trimethylolpropane, adduct of xylylene diisocyanate and trimethylolpropane.

(5) Diisothiocyanate Tetramethylene diisothiocyanate, hexamethylene diisothiocyanate, p-phenylene diisothiocyanate, xylylene-1,4-diisothiocyanate, ethyridine diisothiocyanate.

Similarly, examples of the B substance suitable for such a combination include the following compounds.

(1) Water (2) Polyols and polythiols Ethylene glycol, 1,4-butanediol, catechol, resorcinol, hydroquinone, 1,2-dihydroxy-4-methylbenzene, 1,3-dihydroxy-5-methylbenzene, 3, 4-dihydroxy-1-methylbenzene, 3,5-dihydroxy-1-methylbenzene, 2,4-dihydroxy-1-ethylbenzene, 1,3-naphthalenediol, 1,5-naphthalenediol, 2,3-naphthalenediol ,
2,7-naphthalenediol, polythiol (3) polyamine ethylenediamine, tetramethylenediamine,
Pentamethylene diamine, hexamethylene diamine, p-phenylene diamine, m-phenylene diamine, 2-hydroxytrimethylene diamine,
Diethylenetriamine, triethylenetetraamine, diethylaminopropylamine, tetraethylenepentamine, adducts of epoxy compounds and amines.

(4) Piperazine Piperazine, 2-methylpiperazine, 2,5-
Dimethylpiperazine.

When using multiple types of substances A or B, polyurethane resins or polyurea resins prepared using substances A and B may contain both urethane bonds and urea bonds in their molecular chains, or may contain both urethane bonds and urea bonds. In some cases, the molecular chain contains both thiourethane bonds, and these are also included in the expression polyurethane resin or polyurea resin, as well as those having only urethane bonds or urea bonds.

Furthermore, in the above combination of substances A and B, by replacing substance A with acid chloride, sulfonyl chloride, or bischloroformate as exemplified below, an outer shell made of various resin materials such as polyamide resin can be formed. It can also be formed.

(1) Acid chloride oxazoloyl chloride, succinoyl chloride, adipoyl chloride, sebacoyl chloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, fumaroyl chloride, 1,4-cyclohexane dicarbonyl chloride, Polyester with acid chloride functionality, polyamide with acid chloride functionality.

(2) Sulfonyl chloride 1,3-benzenedisulfonyl chloride,
1,4-benzenedisulfonyl chloride, 1,
5-naphthalenedisulfonyl chloride, 2,7
-naphthalenedisulfonyl chloride, p, p'-
Oxybis (benzenedisulfonyl chloride),
1,6-hexanedisulfonyl chloride.

(3) Bischloroformate Ethylene bis(chloroformate), tetramethylene bis(chloroformate), 2,2'-dimethyl-1,3-propane bis(chloroformate), p-propane bis(chloroformate) mate).

Furthermore, when dispersing a hydrophobic liquid consisting of substance A and a core substance into microdroplets in a hydrophilic liquid containing substance A and a protective colloid-forming material (hydrophilic polymer compound, surfactant, etc.), It is preferable to mix a low boiling point solvent or a polar solvent with the hydrophobic liquid consisting of the A substance and the core substance. These low boiling point solvents or polar solvents contribute to promoting the formation of an outer shell, which is a reaction product between substance A and substance B. 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 material for the outer shell is not particularly limited as long as it has the property of breaking under pressure, and in addition to the polymer materials mentioned above, for example, polymers of styrene or substituted products thereof, or co-producers thereof may be used. Polymers (for example, polystyrene, polyparachlorostyrene, styrene/butadiene copolymer, styrene/acrylic acid copolymer, styrene/acrylic acid ester copolymer, styrene/methacrylic acid copolymer, styrene/methacrylic acid ester copolymer) polymers, styrene/maleic anhydride copolymers, styrene/vinyl acetate copolymers, etc.), polyvinyltoluene resins, acrylic ester homopolymers, methacrylic ester homopolymers, xylene resins, methyl vinyl ether/maleic anhydride resins , vinyl butyral resin, polyvinyl alcohol resin,
Further, polyvinylpyrrolidone and the like can be mentioned.

Further, the outer shell of the capsule toner may be a composite wall formed from various polymeric materials.

The composite wall preferably used in the present invention is a composite wall made of polyurea resin and/or polyurethane resin and polyamide resin. For a composite wall made of polyurethane resin and polyamide resin, for example, use polyisocyanate and acid chloride as the above-mentioned substances A, and polyamine and polyol as substances B, adjust the pH of the emulsifying medium that will become the reaction liquid, and then heat it. It can be prepared by Note that if the amount of polyamine in this reaction system is in excess of the amount required for the reaction with acid chloride, a composite wall consisting of polyurea resin, polyurethane resin, and polyamide resin will be produced. In addition, the composite wall made of polyurea resin and polyamide resin is
It can be prepared by using polyisocyanate and acid chloride as the substances and polyamine as the B substance, adjusting the pH of the emulsifying medium serving as the reaction solution, and then heating it.

Examples of specific compounds of polyisocyanates, acid chlorides, polyamines, and polyols used to produce composite walls made of the above-mentioned polyurea resins and/or polyurethane resins, and polyamide resins include polyisocyanates, polyurethane resins, polyamines, and polyols. , and as for the polyols, mention may be made of the compounds listed for the formation of the outer shell of polyurethane or polyurea.

Examples of acid chlorides include adipoyl chloride, sebacoyl chloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, fumaroyl chloride, 1,4-cyclohexanedicarbonyl chloride, 4,4'-biphenyldicarbonyl chloride, , 4'-sulfonyldibenzoyl chloride, phosgene, polyesters containing acid chloride groups, and polyamides containing acid chloride groups.

Note that dicarboxylic acid or an acid anhydride thereof may be used instead of the above acid chloride. Examples of dicarboxylic acids include adipic acid, sebacic acid, phthalic acid, terephthalic acid, fumaric acid, 1,4-cyclohexanedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. An example of the acid anhydride is phthalic anhydride.

The core material used in the present invention contains a display recording material for converting a latent image into a visible image. The display recording material usually uses a coloring agent that provides a visible image as it is, but it is also possible to use a substance that indirectly provides a visible image, such as a fluorescent material.

As the colorant, dyes, pigments, etc. that have been conventionally used in dry or wet toners can be used. For example, carbon black can be used as a black toner. Alternatively, grafted carbon black can also be used.
Examples of chromatic colorants include copper phthalocyanine, amide compounds of sulfone higher fatty acids or aromatic sulfonic acids, blue colorants such as derivative dyes, and yellow colorants such as benzidine derivatives collectively known as diazo yellow. and red coloring agents such as polytungstophosphoric acid, rhodamine B lake which is a double salt of molybdic acid and xanthine dye, carmine 6B which is an azo pigment, and quinacridone derivatives.

The liquid binder (containing at least a high boiling point solvent) contained in the core material of the capsule toner of the present invention disperses and holds the display recording material etc. in the core material and separates the display recording material formed on the latent image. When a visible image is transferred to a support medium such as paper, it functions to fix the visible image on the support medium.

Examples of binders used for the above purpose include high-boiling solvents, such as those having a boiling point of 180° C. or higher, and polymers.

Examples of high boiling point solvents that can be used as binders in the present invention include the following compounds.

(1) Phthalate esters dibutyl phthalate, dihexyl phthalate,
diheptyl phthalate, dioctyl phthalate,
Dinonyl phthalate, didecyl phthalate, butylphthalyl butyl glycolate, dibutyl monochlorophthalate.

(2) Phosphate esters tricresyl phosphate, tricylelyl phosphate, tris(isopropylphenyl) phosphate, tributyl phosphate, trihexyl phosphate, trioctyl phosphate,
Trinonyl phosphate, tridecyl phosphate, trioleyl phosphate, tris (butoxyethyl) phosphate, tris (chlorethyl) phosphace, tris (dichloropropyl)
Phosphate.

(3) Citric acid esters o-acetyl triethyl citrate, o-acetyl tributyl citrate, o-acetyl trihexyl citrate, o-acetyl trioctyl citrate, o-acetyl trinonyl citrate,
o-acetyltridecyl 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, dodecyl benzoate, tridecyl benzoate, tetradecyl benzoate, hexadecyl benzoate, octadecyl benzoate, oleyl benzoate, pentyl o-methyl benzoate, decyl p-methyl benzoate, octyl o-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, Isosorbide dicaprylate.

(6) Alkylnaphthalenes Methylnaphthalene, dimethylnaphthalene, trimethylnaphthalene, monoisopropylnaphthalene, diisopropylnaphthalene, triisopropylnaphthalene, tetraisopropylnaphthalene,
Monomethyl, diethylnaphthalene, isooctylnaphthalene.

(7) Alkyl diphenyl ethers o-methyl diphenyl ether, m-methyl diphenyl ether, p-methyl diphenyl ether.

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

(9) Trimellitic acid esters trioctyl trimellitate.

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

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

JP 46-23233, JP 49-29461: JP 47-1031, JP 50-62632, JP 50-
No. 82078, No. 51-26035, No. 51-26036, No. 51
-26037, US Patent No. 51-27921, US Patent No. 51-27922: US Patent No. 2322027, US Patent No. 2353262, US Patent No.
No. 2533514, No. 2835579, No. 2852383, No. 3287134, No. 3554755, No. 3676137,
Same No. 3676142, Same No. 3700454, Same No. 3748141,
British Patent No. 3837863, British Patent No. 958441, British Patent No. 1222753
Issue: OLS No. 2538889.

Particularly preferred high-boiling solvents for use in the present invention are phthalates, phosphates, alkylnaphthalenes, and diarylalkane.

The core material of the capsule toner of the present invention is an organic liquid having a boiling point of 100 to 250°C (preferably 140 to 220°C) that does not substantially dissolve or swell the polymer contained in the core material. It may further contain. As such an organic liquid, it is desirable to use an aliphatic saturated hydrocarbon or an organic liquid mixture containing an aliphatic saturated hydrocarbon as a main component.

Aliphatic saturated hydrocarbons are generally used in various applications as a mixture of a plurality of aliphatic saturated hydrocarbon fractions having a certain boiling point range. Among these, particularly preferred examples of aliphatic saturated hydrocarbons include those with a boiling point range (initial boiling point to dry point) of 115 to 142°C (e.g., Isopar E, trade name, manufactured by Exxon Chemical Co., Ltd.;
(same below), boiling point range of 158 to 177℃ (e.g.
Isopar G), with a boiling point range of 174-189℃ (e.g.
Isopar H), with a boiling point range of 188-210℃ (e.g.
Isopar L) and those having a boiling point range of 207 to 258°C (eg Isopar M).

Further, as examples of preferable compounds for the polymer used as a binder in the present invention, the following compounds can be mentioned.

Polyolefin, olefin copolymer, styrene resin, styrene-butadiene copolymer,
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, homopolymer or copolymer of acrylic acid ester, homopolymer or copolymer of methacrylic acid ester, copolymer oligomer of acrylic acid and long-chain alkyl methacrylate, polyvinyl acetate, polychloride vinyl.

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

Special Publication No. 48-30499, No. 49-1588, No. 54-
No. 8104: Japanese Patent Publication No. 48-75032, No. 48-78931, No. 49-
No. 17739, No. 51-132838, No. 52-98531, No. 52
−108134, No. 52-119937, No. 53-1028, No.
No. 53-36243, No. 53-118049, No. 55-89854,
No. 55-166655: U.S. Patent No. 3,893,933.

Particularly preferred polymers for inclusion in the core material used in the present invention are homopolymers or copolymers of acrylic esters, homopolymers or copolymers of methacrylic esters, or styrene-butadiene copolymers.

In addition, the binder in the present invention consists of the above-mentioned polymer and a high boiling point solvent (and, if desired, a temperature of 100 to 250°C (preferably 140 to 220°C) that does not substantially dissolve or swell the polymer.
It may also be a mixture with an organic liquid (having a boiling point of

The core material of the capsule toner of the present invention contains a display recording material and a liquid binder as described above, but it can also contain various additive materials as desired. Examples of such additives include mold release agents such as fluoroplastic powders, which are effective in preventing offset. On the other hand, the outer shell of the capsule toner of the present invention is made of a resin material, and if desired, this outer shell may also contain a metal-containing dye, a charge control agent such as nigrosine, a fluidizing agent such as hydrophobic silica, or Other optional additives can be added. These additive substances can be incorporated into the outer shell of the capsule toner at any time, such as when the outer shell is formed or after the capsule toner is separated and dried.

In addition, the core substance of the capsule toner of the present invention includes:
If desired, a white pigment such as calcium carbonate or titanium dioxide may be included as a color toning agent.

It goes without saying that all of the various materials and substances used in the present invention can be used as a mixture of two or more.

In the process of preparing microcapsules for producing the capsule toner of the present invention, a hydrophilic polymer compound (or surfactant) can be used as a protective colloid to emulsify and disperse the hydrophobic core substance in the form of microdroplets. . Among these, hydrophilic polymer compounds are preferred. Such hydrophilic polymer compounds can be divided into hydrophilic polymer natural products, derivatives thereof, and hydrophilic synthetic polymer compounds.

Examples of hydrophilic polymer natural products and their derivatives include ordinary gelatin, gelatin derivatives obtained by reacting gelatin with other reactive substances, gelatin graft polymers in which polymer chains are grafted to gelatin, albumin, Examples include proteins such as casein; cellulose derivatives such as hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and cellulose sulfate; and sugar derivatives such as gum arabic, sodium alginate, and starch derivatives.

As the above-mentioned ordinary gelatin, various types of gelatin can be used, such as lime-treated gelatin, acid-treated gelatin, gelatin hydrolyzate, gelatin enzymatically decomposed product, and the like.

Examples of gelatin graft polymers include gelatin obtained by grafting homopolymers or copolymers made of vinyl monomers such as acrylic acid, methacrylic acid, derivatives thereof such as esters and amides, acrylonitrile, and styrene. I can list things. Among these, graft polymers of gelatin and polymers having some degree of compatibility with gelatin, such as those obtained from acrylic acid, methacrylic acid, acrylamide, methacrylamide, hydroxyalkyl methacrylate, etc., are preferred. These gelatin graft polymers are
For example, U.S. Patent No. 2,763,625;
It is described in Specification No. 2831767, Specification No. 2956884, etc.

Examples of hydrophilic synthetic polymer compounds include polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, etc. Mention may be made of polymers and copolymers.

In addition, examples of hydrophilic synthetic polymer compounds include, for example, West German Open Patent Publication (OLS) No. 2312708,
It is described in U.S. Pat. No. 3,620,751, U.S. Pat.

Examples of surfactants include known anionic surfactants and nonionic surfactants. Moreover, a surfactant can also be used in combination with a hydrophilic polymer compound.

The hydrophilic polymer compound (and/or surfactant) introduced into the reaction system as described above is removed from the microcapsule dispersion as much as possible by washing with water after the encapsulation reaction is completed.
It is desirable to reduce the amount of hydrophilic polymer compound (and/or surfactant) that adheres to the surface of the capsule toner obtained by spray drying or other drying operations.

As described above, after microcapsules are prepared by forming an outer shell around a core material containing a display recording material, a binder, etc. in an aqueous medium, the microcapsules are separated from the liquid phase (aqueous medium). dried. This separation and drying operation is usually carried out by spray drying a dispersion containing microcapsules. Also,
A method such as freeze drying can also be used to separate and dry the microcapsules from the liquid phase. Alternatively, a method of heating and drying a slurry containing microcapsules using a heating drying device such as an oven can also be used.

As described above, the capsule toner of the present invention is characterized in that fluororesin particles are attached to or contained on the surface of the outer shell. The amount of fluororesin attached to or contained in the outer shell of the capsule toner is preferably in the range of 0.1 to 10% by weight, and more preferably in the range of 1 to 8% by weight, based on the total weight of the capsule toner.

The fluororesin that can be used in the present invention is not particularly limited as long as it is a polymeric substance containing fluorine atoms in its molecular structure. Examples of preferred fluororesins for use in the present invention include polytetrafluoropolyethylene resin, tetrafluoroethylene/hexafluoropropylene copolymer resin, tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer resin, and tetrafluoroethylene Ethylene/ethylene copolymer resin, polychloroethylene trifluoride resin, polyvinylidene fluoride resin, polyvinyl fluoride resin, ethylene chloride trifluoride/ethylene copolymer resin, vinylidene fluoride/ethylene trifluoride copolymer, Vinylidene fluoride/propylene pentafluoride copolymer, vinylidene fluoride/propylene hexafluoride copolymer, silicone fluoride, phosphazene, ethylene tetrafluoride/methyl vinyl ether perfluoride copolymer,
and tetrafluoroethylene/propylene copolymers.

Examples of methods for attaching or containing fluororesin particles to the surface of the outer shell of the capsule toner include introducing fine particulate fluororesin into a dispersion containing microcapsules and then spray-drying the mixture dispersion; Alternatively, a method of drying by heating in an oven or the like; a method of introducing a dispersion containing microcapsules and a dispersion containing fine particulate fluororesin into a spray dryer at the same time and performing spray drying; A method may be used in which fine particulate fluororesin is previously dispersed in the reaction solution before starting the encapsulation reaction, and then the encapsulation reaction and drying of the microcapsules are carried out.

In the present invention, fluororesin particles are attached to or contained in the surface of the outer shell of the capsule toner. For example, a typical state is when particulate fluororesin is attached or embedded in a dispersed state with part or most of it exposed to the outside on the surface of the outer shell of a capsule toner. I can list the states where I am.

Microcapsules dried by a method such as spray drying may then be subjected to heat treatment. This heat treatment further improves the powder characteristics of the capsule toner of the present invention. Preferably, the heat treatment is carried out at a temperature in the range of 50 to 300 °C, and even 80 °C.
Particularly preferred is heating at a temperature in the range ~150<0>C. The heating time varies depending on the heating temperature and the type of core material used, but is usually selected from a range of 10 minutes to 48 hours, and more generally from a range of 2 to 24 hours.

There are no particular restrictions on the equipment and equipment used for the heat treatment, and any heating drying equipment such as an electric furnace, muffle furnace, hot plate, electric dryer, fluidized bed dryer, infrared dryer, etc. can be used. .

Next, examples of the present invention will be shown. In the Examples, "%" means "% by weight" unless otherwise specified.

[Example 1] 10 g of a mixed solvent consisting of acetone/methylene chloride = 1/3 ratio, 3 g of carbon black, 15 g of magnetite (trade name: EPT-1000, manufactured by Toda Kogyo Co., Ltd.) and 27 g of diisopropylnaphthalene
A primary liquid was obtained by mixing the mixture with the dispersion liquid in a mortar. Then, a 3:1 molar adduct of hexamethylene diisocyanate and hexanetriol 4
g and 1 g of adipic acid chloride were added to the primary liquid to obtain a secondary liquid. However, these mixed liquids were prepared while controlling the liquid temperature to 25°C or lower.

The above secondary liquid was gradually poured into a solution obtained by dissolving 15 g of gum arabic in 60 ml of water at 20° C. with vigorous stirring to prepare an oil-in-water emulsion having an oil droplet diameter of 5 to 15 μm. The preparation of this emulsion involves lowering the temperature of the liquid by cooling the outside of the container.
The temperature was controlled to below 20°C. After the emulsion was formed, stirring was continued and the mixture was heated to 40°C.
of water was added. Next, the temperature of this emulsion was gradually increased to 90°C after 30 minutes.
The temperature of the emulsion was maintained at this temperature for 20 minutes, thereby completing the encapsulation.

Next, this microcapsule dispersion was separated into microcapsules and an aqueous gum arabic solution by centrifugation (5000 rpm).

The microcapsules separated as described above were washed by centrifugation to reduce the amount of gum arabic adhering to the surface of the outer shell of the microcapsules. The microcapsules are washed by centrifugation by first dispersing the separated microcapsules in water so that the dispersion amount is approximately 30%, and then centrifuging the dispersion under the same conditions (5000 rpm) as above. This was carried out by a method of separating microcapsules and an aqueous phase.

After washing the microcapsules twice using this centrifugal separation method, the microcapsule dispersion was mixed with a particulate fluororesin (average particle size:
A dispersion of 0.2 to 0.4 μm) in water (fluororesin content: 60% by weight) is added so that the fluororesin is 3% by weight based on the total weight of the microcapsules, and the mixture is spray-dried to produce capsule toner. I got it.

The powder properties and volume resistivity of the obtained capsule toner were determined at () 14℃, 40%RH and () 30℃,
The test was conducted under two types of temperature and humidity conditions: 90% RH.

The powder characteristics are that under both conditions () and (), each capsule particle exists independently;
Moreover, it was in a state of smooth flow.

The volume resistivity was 10 ¹⁵ Ω-cm under the conditions () and 10 ¹³ Ω-cm under the conditions ().

The above capsule toner was used as a one-component magnetic capsule toner at 14℃, 40%RH, and 30℃.
When an electrostatic latent image formed by ordinary electrophotography was developed using a magnetic brush method under the conditions of ℃ and 90% RH, a good visible image was obtained under all conditions.

The above visible image is fixed using a pressure fixing roller.
When pressure fixing was performed at a pressure of 350 kg/cm ² , a copy image with good fixing properties, clarity, and high image density was obtained. In addition, almost no toner adhered to the roller.

[Example 2] Magnetite (trade name: EPT-
1000) was mixed for 2 hours using an automatic mortar to prepare a dispersion, and ethyl acetate was mixed in a compatible manner to obtain a primary liquid. Then, 4 g of a 3:1 molar adduct of hexamethylene diisocyanate and hexanetriol and 1 g of terephthalic acid chloride were added to the primary liquid to obtain a secondary liquid. However, these mixed liquids were prepared while controlling the liquid temperature to 25°C or lower.

Fine particulate fluororesin (average particle size: 0.2~
0.4 μm) in water (fluororesin content: 60% by weight) was added, and the above secondary liquid was gradually poured into this with vigorous stirring to form an oil droplet in water with a diameter of 5 to 15 μm. An oil drop emulsion was prepared. This emulsion was prepared while controlling the liquid temperature to 20° C. or lower by cooling the outside of the container. After the emulsion was formed, stirring was continued, and 100 g of a 5% triethylenediamine aqueous solution at 20° C. was added thereto, and the pH was adjusted to 10 with sodium carbonate. Next, the temperature of this emulsion was gradually increased to 90°C after 30 minutes.
The temperature of the emulsion was maintained at this temperature for 20 minutes, thereby completing the encapsulation.

Next, this microcapsule dispersion was separated into microcapsules and an aqueous gum arabic solution by centrifugation (5000 rpm).

The microcapsules separated as described above were washed by centrifugation to reduce the amount of gum arabic adhering to the surface of the outer shell of the microcapsules. The microcapsules are washed by centrifugation by first dispersing the separated microcapsules in water so that the dispersion amount is approximately 30%, and then centrifuging the dispersion under the same conditions (5000 rpm) as above. This was carried out by a method of separating microcapsules and an aqueous phase.

Washing of the microcapsules using this centrifugation method was repeated twice.

The obtained capsule slurry was heated in an oven for 100 min.
After drying at °C, the surface was observed with a scanning electron microscope, and it was confirmed that the fine particulate fluorinated resin was dispersed and retained.

The powder properties and volume resistivity of the above capsule toner are () 14℃, 40%RH and () 30℃,
The test was conducted under two types of temperature and humidity conditions: 90% RH.

The powder characteristics are that under both conditions () and (), each capsule particle exists independently;
Moreover, it was in a state of smooth flow.

The volume resistivity was 10 ¹⁵ Ω-cm under the conditions () and 10 ¹⁴ Ω-cm under the conditions ().

The above capsule toner was used as a one-component magnetic capsule toner at 14℃, 40%RH, and 30℃.
When an electrostatic latent image formed by ordinary electrophotography was developed using a magnetic brush method under the conditions of ℃ and 90% RH, a good visible image was obtained under all conditions.

The above visible image is fixed using a pressure fixing roller.
When pressure fixing was performed at a pressure of 350 kg/cm ² , a copy image with good fixing properties, clarity, and high image density was obtained. Further, almost no toner adhesion to the roller occurred.

[Comparative Example 1] A capsule toner was obtained in the same manner as in Example 1 except that the fluororesin was not added to the microcapsule dispersion.

The powder properties and volume resistivity of the obtained capsule toner were determined at () 14℃, 40%RH and () 30℃,
The test was conducted under two types of temperature and humidity conditions: 90% RH.

Under the conditions (), the powder properties were such that each capsule particle existed independently and had smooth flow. Further, under the conditions (), some aggregates were observed, but normal flow was possible.

The volume resistivity was 10 ¹³ Ω-cm under the conditions () and 10 ⁹ Ω-cm under the conditions ().

The above capsule toner was used as a one-component magnetic capsule toner at 14℃, 40%RH, and 30℃.
An electrostatic latent image formed by ordinary electrophotography at 90% RH was developed by a magnetic brush method. Of these, the visible image obtained by developing the electrostatic latent image formed under the conditions of 14°C and 40% RH was good, but the visible image obtained by developing the electrostatic latent image formed under the conditions of 30°C and 90% RH was The visible image obtained by developing the image was slightly lacking in image density.

[Comparative Example 2] Polyethylene 40 parts by weight (AC392, manufactured by Allied Chemical Co., Ltd.) Magnetic powder 20 parts by weight (Magnetite, average particle size: 0.4 μm, Toda Industries)
(manufactured by Co., Ltd.) The above mixture was heated and kneaded with a roll. After cooling the mixture well, it was coarsely pulverized and further finely pulverized using a jet mill to produce core material particles with an average size of about 15 μm. The softening point of the obtained particles is approximately 100℃
It was hot.

Separately, a styrene/methyl methacrylate/butyl acrylate/acrylic acid copolymer emulsion (acrylic acid 3 mol %, solid content 40 weight %) was prepared. The minimum film forming temperature of this emulsion is approximately 20
°C, the electrical resistance of the film after deposition is approximately 10 ¹⁵ Ω ^- cm
It was hot.

The core material is added to 20 parts by weight of this emulsion.
56 parts by weight, 2 parts by weight of ferrite (ZnO Fe ₂ O ₃ ) powder, 0.4 parts by weight of chromium metal complex compound (Cr-2, manufactured by Orient Chemical Co., Ltd.) and 260 parts by weight of water,
Spray drying was carried out using a spray dryer at an inlet temperature of 100°C and an outlet temperature of 70°C to provide a crosslinked resin coating layer containing the copolymer emulsion as a main component around the core material particles.

Hydrophobic silica (Aerosil R-972) was added to the encapsulated toner thus obtained to obtain a capsule toner.

The powder characteristics of the above capsule toner are ()14
It was investigated under two types of temperature and humidity conditions: ℃, 40%RH and ()30℃, 90%RH.

The powder characteristics are that under both conditions () and (), each capsule particle exists independently;
Moreover, it was in a state of smooth flow.

The above capsule toner was used as a one-component magnetic capsule toner at 14℃, 40%RH, and 30℃.
When an electrostatic latent image formed by ordinary electrophotography was developed using a magnetic brush method under the conditions of ℃ and 90% RH, a good visible image was obtained under all conditions.

The above visible image is fixed using a pressure fixing roller.
A copy image was obtained by pressure fixing at a pressure of 350 kg/cm ² .
When the resulting image was rubbed with a finger, some of the toner peeled off and adhered to the finger, causing stains on the copied image.

[Comparative Example 3] In Comparative Example 2, fluororesin fine particles (average particle size:
A capsule toner was obtained in the same manner as in Comparative Example 2, except that 0.2 to 0.4 μm) was used.

The above capsule toner was evaluated in terms of powder properties, visible images, and copied images in the same manner as in Comparative Example 2, and similar results were obtained.

[Comparative Example 4] A capsule toner was produced in the same manner as in Example 1 except that hydrophobic silica (Aerosil R-972) was used instead of the fluororesin fine particles (average particle size: 0.2 to 0.4 μm). Obtained.

The powder properties and volume resistivity of the obtained capsule toner were determined at () 14℃, 40%RH and () 30℃,
The test was conducted under two types of temperature and humidity conditions: 90% RH.

Under the conditions (), the powder properties were such that each capsule particle existed independently and had smooth flow. Further, under the conditions (), some aggregates were observed, but normal flow was possible.

The volume resistivity was 10 ¹⁴ Ω-cm under the conditions () and 10 ¹² Ω-cm under the conditions ().

The above capsule toner was used as a one-component magnetic capsule toner at 14℃, 40%RH, and 30℃.
An electrostatic latent image formed by ordinary electrophotography at 90% RH was developed by a magnetic brush method.

The above visible image is fixed using a pressure fixing roller.
A copy image was obtained by pressure fixing at a pressure of 350 kg/cm ² .
Of these, the visible image obtained by developing the electrostatic latent image formed under the conditions of 14°C and 40% RH was good, but the visible image obtained by developing the electrostatic latent image formed under the conditions of 30°C and 90% RH was In the visible image obtained by developing the image, blurring occurred in the image.

Claims (1)

[Claims] 1. A capsule toner comprising a core material containing a liquid binder and a display/recording material and an outer shell formed around the core material, in which fluororesin particles are attached to the surface of the outer shell. or a capsule toner characterized by containing. 2. The capsule toner according to claim 1, wherein the amount of fluororesin particles attached to or contained in the outer shell of the capsule toner is in the range of 0.1 to 10% by weight based on the total weight of the capsule toner. 3. The capsule toner according to claim 1, wherein the outer shell is made of polyurethane resin or polyurea resin.