JPS59127061A - Microencapsulated toner - Google Patents

Abstract

PURPOSE:To form a pressure fixable toner superior in pressure fixability and developability by mixing a mixture of materials in a binder resin contg. a compd. having a hydrocarbon chain and dispersing them in hot water into suspension and then coating their surfaces with the resin. CONSTITUTION:A mixture of materials consisting of a binder resin contg. a compd. having a hydrocarbon chain, and a colorant is melted and mixed. It is dispersed and suspended in hot water using a dispersion stabilizer consisting of a finely divided inorg. compd. hardly soluble in water, and the surfaces of produced particles are coated with the resin. As the inorg. dispersant, salts hardly soluble in water, such as BaSO4, inorganic polymers, such as talc, bentonite, silica, and diatomaceous earth, and powders of metals and metal oxides, etc. are enumerable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microcapsule toner used in electrophotography, static, electrophotography, magnetic recording, electrostatic printing, or the like.

Conventionally, an electrostatic latent image, a magnetic latent image, or the like is developed with colored fine powder called toner, and then when the image is desired to be preserved, an operation called "fixing" is performed. Such fixing methods include a method in which the latent image bearing surface is transferred as it is to a transfer member, and then the toner is melted in a heat chamber and at the same time the toner is embedded, and a solvent is used to melt the toner and adhere. and then remove the solvent,
A known method is to apply a resin solution called a fixer onto an image for identification.

Development methods for visualizing toner using an electrical latent image include, for example, the magnetic brush method described in US Pat. No. 2,874,063, the cascade development method described in US Pat. No. 2,618,552, and US Pat. A number of development methods are known, such as the powder cloud method, the fur brush development method, and the liquid development method described in No. The toners used in these development and fixing methods are constructed so as to satisfy the various development and fixing methods described above and provide sufficient performance. Conventionally, carbon black,
A coloring material such as iron oxide is mixed with a binding material such as I-linutylene phenol resin, and the latter is crushed into a fine powder and subjected to operations such as classification as necessary. It is applied by mixing with carrier particles such as peas and conductive agents.

Various types of toners used in this manner are known. These are constructed to be compatible with the above-mentioned developing method and fixing method.

Although the toner is constructed in such a way that it satisfies the development and fixation characteristics, it is generally difficult to achieve a perfect balance between the development and fixation characteristics. This is because there are fundamentally conflicting performance requirements, such as the toner must have an adhesion force and cohesive force, and each toner must move independently for development. In particular, these conditions have become even more severe recently when high-performance toners, toners that develop and fix at high speed, and toners that fix with little energy (for example, very little pressure) are required. Become. In other words, the more an attempt is made to make a toner with good fixing properties, the more severe the development characteristics become. In order to solve this contradiction, a capsule-shaped toner with developing properties and fixing properties separated into a shell and a core has been proposed.

However, in reality, it is extremely difficult to produce capsules in the form of ultrafine particles such as toner, and it is not easy to actually obtain all the sufficient properties.

In addition, as mentioned above, the conventional toner manufacturing method is to mix a thermoplastic resin and a coloring agent such as a dye or pigment, melt and mix the mixture at high temperature, cool the mixture to room temperature, and grind it into fine particles. It is. However, due to the manufacturing method, the toner manufactured by this method does not have a constant shape or particle size, and to achieve uniformity among the toners and uniformity within the toner, it is essentially rotation. The resulting inadequacies in the practical performance of toners have been explained in various ways.

It costs a lot of money to prepare a thinner using this manufacturing method.9 In particular, step 5 to obtain fine particles requires an extremely large amount of energy, which is difficult in terms of equipment cost and thinning process. Closed a lot.

Furthermore, such a manufacturing method greatly limits the materials that can be used. In other words, in order to obtain a fine and uniform toner, it was necessary to mix the particles uniformly, and it was necessary to select a material that had good kneading properties. Characteristics are a big problem in terms of productivity.In order to be produced as a toner, the binder must first be brittle, which does not necessarily match the characteristics of pine paste required from the performance of the toner. Due to the required performance of the toner, it was not possible to use a binder with the desired characteristics using conventional manufacturing methods. A method has also been proposed in which toner particles are obtained by performing this process.

However, when producing toner using this method, it is difficult to completely eliminate emulsifiers and dispersants used to stabilize dispersion, and it is extremely difficult to obtain toner with sufficient performance. Ta.

An object of the present invention is to provide a toner for pressure fixing that has excellent pressure fixing properties and excellent developability.

An object of the present invention is to provide a toner having particularly excellent pressure fixing properties and good developing performance.

The object of the present invention is to provide a donor that is stable even after repeated use, provides excellent performance, and does not aggregate or contaminate the surface of a photoreceptor with carrier or metal sleeve.
There is C.

An object of the present invention is to provide a pressure-fixed toner that does not cause offset to a pressure roller, carrier development nucleation, or contamination of a photoreceptor.

Furthermore, it is an object of the present invention to provide a toner that is stable and does not change even after multiple uses, and is also stable and does not change in a storage container for a long period of time. Furthermore, an object of the present invention is to propose a novel method that solves the problems of the conventional manufacturing method described above.

It is an object of the present invention to provide a method for producing toner having uniform shape and homogeneous composition.

A further object of the present invention is, in particular, to obtain toner particles in which pigments are uniformly dispersed.

A further object of the present invention is to propose a method for producing toner at a lower cost.

The present invention which achieves the above object is to form particles using a process of mixing a raw material mixture of a binder resin containing a compound having a hydrocarbon chain and suspending and dispersing it in hot water to form particles. It is a microcapsule toner whose surface is coated with a resin, and in particular, an inorganic dispersant is used in the suspension process, and a combination of the raw material mixture and the inorganic dispersant is used in the combination of the raw material mixture and the inorganic dispersant. In addition, the raw material mixture is either (a) cationically charged by adding a cationic compound or a poorly water-soluble specific amine compound in water, or (b) anionically charged by the addition of an anionic compound, and the inorganic material is dispersed. The agent has a charge opposite to that of the raw material mixture particles in water, and the material mixture particles are suspended so that the surface of the material mixture particles is uniformly coated with the inorganic dispersant. This microcapsule toner is made by coating the surface of particles with a uniform particle size distribution, which are firmly bonded to a dispersant through i,on bonds, with a resin.

Conventionally, methods for obtaining fine particles by dispersing them in water are known.

This method uses a process in which a raw material mixture is melt-mixed and dispersed in hot water containing surfactants and stabilizers to form particles. Even if this method is used, fine particles f! : It is possible to obtain the desired particle size, but in this case, 1) If you try to obtain the desired particle size, coarse particles or small particles that are much larger than the desired particle size will be generated, making it difficult to select the desired particle size. Sweeping is necessary for cleaning. Furthermore, it is difficult to remove surfactants and stabilizers from the particle surfaces, and it is also difficult to treat and reuse or dispose of this dispersion medium. On the other hand, the method according to the present invention is a method in which particles are created by melt-mixing the causative mixture and using an inorganic dispersant. An inorganic dispersant is a finely powdered inorganic compound that is poorly soluble in water.
O4, CaSO4, B aCOs, CaCO2,
Examples include poorly water-soluble salts such as MgCO3 and Ca5(PO4)2, inorganic polymers such as Merck bentonite, diatomaceous earth, clay, and powders of metals and metal oxides.

In addition to the selection of the stabilizer mentioned above, stirring is an important condition for suspension, and since this determines the particle size and particle stability, appropriate stirring conditions are important and should be selected depending on the purpose. be done.

Particularly preferred conditions for suspension and dispersion in the present invention are a combination of the above-mentioned specific material mixture and inorganic dispersant.

In this system, the interface of the raw material mixture particles is cationically or anionically charged and forms stable aggregates through interaction with the inorganic dispersant.

In other words, the surface of the polymerizable monomer particles is completely and uniformly coated with an inorganic dispersant that is strongly bound by ionic bonds, which prevents the particles from coalescing. In the case of an inorganic dispersant that is tightly bound, it is far superior to conventional methods in which the dispersant is simply adsorbed to polymer particles or dispersed between particles to prevent coalescence. It is clear that a strong bond is formed.

Such a method has the following advantages.

(1) Stirring speed The desired particle size can be arbitrarily set by appropriately changing the amount of ionic substance and the amount of inorganic dispersant.

(2) Since there is no coalescence of particles, the particle size distribution of the produced particles is narrow.

(3) Since the ratio of particles to water can be increased, production efficiency can be increased.

(4) Particle formation is possible with low speed stirring.

・In the present invention, a compound having a hydrocarbon chain and Fic
These are hydrocarbons of 12 to Cso, fatty acids, their entele, metal soaps, fatty alcohols, polyhydric alcohols, and their metal salts, their chlorides, heptadides, amides, and bisamides. Commercially available products include paraffin waknu,
It is sold as microcrystalline wax amide wax.

Examples of long-chain compounds having a hydrocarbon chain include the following.

(1) Compounds having non-n 2n 10n rumals and isoparaffins represented by CH (n = 12-50) and some unsaturated bonds therein.

Examples include C12n-Dodecane C,12(-2H) 1-DodecaneC12
n-Tridecane C12 (-2H) 1-Trid@caneC14
n-Tetradecane C14(-2H) 1-TetradeceneC
15n-Pentadecane C,5(-2H) 1-PentadaceneC
16n-Hexadeeana C16(-2H) 1-HsxadeeenaC1
6n-0c tade cans ClB (-2H) 1-OctadeceneC
19n-Nonad@eans C4q (-2H) 1-NonadecsneC
2on-EicosaneC20(-2H
) 1-Eicogen*C22n-D Ot
OS & n @C24n-Tetracosane C2B n -00tJL e O8a
n @C32n-Dotr1aeontaneC56n
-Hexatrlaontane, staralene C30H50 and staralene 2,6.10,15,19.23 hexamethyltetracosane (C5oH62).

included.

(2) Fatty acids having a hydrocarbon chain such as those mentioned above, as well as mixtures thereof, may also be used in combination with conventionally known binding materials in order to add necessary properties. .

In addition, the camionic compound is a polymer containing the following nitrogen-containing polymerizable monomers as its constituent units, such as diethylaminoether methacrylate, dimethylaminoethyl acrylate, 2-hydroxy-3-methacryloxyglobil, and trimethylammonium. chloride, 2-hydroxy-3-acryloxyglobil, trimethylammonium chloride, diacetone 7-acrylamide, acrylamide) N-vinylcarbazole, vinylpyridine, 2-vinylimidazole, diethylaminoether methacrylate, dimethylaminoethyl acrylate, N-n- Butoxyacrylamide, which is used in admixture with the above-mentioned long-chain compounds, may also be graft-polymerized with the above-mentioned monomers onto the long-chain compounds. Examples of poorly water-soluble organic amines include aliphatic primary amines having 7 or more carbon atoms, such as heptylamine, octylamine, and dodecylamine.

α-2-2 Aliphatic tertiary amine: Aliphatic tertiary amine having a boiling point of 80°C or higher, such as dipropylamine, diisoglobylamine, dibutylamine, cyamylamine, and didodecylamine.

α-2-3 aliphatic tertiary amine: Examples of aliphatic tertiary amines with a boiling point of 80°C or higher include triethylamine, trizolopylamine, tributylamine, triamylamine, n-dodecyldimethylamine,
Examples include n-tetradecyldimethylamine.

α-2-4 aromatic amines: Aniline, methylaniline, dimethylaniline, ethylaniline, diethylaniline, toluidine, dibenzylamine, tribenzylamine, diphenylamine, doliphenylamine, naphthylamine, and the like.

However, primary, secondary, and tertiary amines are used in the form of acidic aqueous solutions.

In addition, anionic compounds are polymers containing the following polymerizable monomers as constituent units, such as 2-acrylamido-2-methylpropanesulfonic acid, N-methylolacrylamide, methacrylic acid, acrylic acid, 2-hydroxyethyl methacrylate, methacrylic cI
These include glycidyl R-2-hydroxypropyl methacrylate, polypropylene glycol monomethacrylate, polyesalene gelicol monomethacrylate, tetrahydrofurfuryl methacrylate, and acid phosphooxyethyl methacrylate.

These monomers can be used in combination with the long-chain compounds mentioned above, but the monomers may also be polymerized with the long-chain compounds. Furthermore, various conventionally known coloring materials can be used as the coloring material. Examples include various pigments and dyes including carbon black.

The inorganic dispersants used in the present invention are anionic, colloidal silica (slo2), bentonite) (81
02/At20. ) etc., and cationic and −
Examples include aluminum oxide (At203). The finer the particle size of the inorganic dispersant, the more effective the effect can be exerted even in a small amount. For example, what is known as colloidal silica has a primary particle average of 40 mμ to 7 mμ in water.
In terms of % concentration...values range from 3.6 to 4.3. For example, aluminum oxide is Almlnlum Oxid manufactured by Degussa, Germany.
e CIJ-order particles with an average diameter of 20 mμ are obtained, which are extremely fine and highly pure. However, Aluminum 0xd
e C indicates an isoelectric point of -9 and is used on the neutral or acidic side.

These can be used in a range of 0.01 weight pH or more based on the raw material mixture. Preferably 0.05 weight ph
r or more.

Next, the method of forming particles by suspension according to the present invention will be explained. A compound having a hydrocarbon chain and a colored body are mixed and heated to melt and knead. Thereafter, the above mixture is dispersed into heated water in which the dispersant is dispersed, and stirring is continued. When observed under a microscope, it is observed that the diameter of the stamp gradually becomes finer and more uniform. After 15 to 30 minutes of stirring, the particles had a wide particle size distribution, but after 30 to 60 minutes, there were no coarse particles at all and they were all uniformly fine. It contains bentonite (SiO□/At20.), colloidal silica 810□, and a trace amount of silanol group (-〇IGH), and it dissociates in water to form a Si tone and eel, and becomes negatively charged in water and exhibits cyanionic properties. Therefore, it is thought that this is because the compound exhibiting cationic properties is ionically bonded strongly and arranged on the surface of the material mixture particles to stabilize the whole, making it difficult for the particles to reagglomerate. Control of particle size is largely influenced by the strength of stirring, the degree of stirring blades, etc. Generally speaking, the stronger the stirring, the more particles with smaller diameters can be obtained, but there is an industrial limit, and the yield may be lowered due to air being mixed into the stirring device.

The inventors of the present invention have conducted extensive research in order to obtain fine particles, and found that in order to form such fine particles, a rotating R (turbine) that has high shear force and rotates at high speed is required.
We have discovered that a dispersion device consisting of a fixed blade (stator) and a dispersion device that disperses by force such as a strong shear force generated in a precisely uniform minute gap between them is extremely effective.These are, for example, TK homomixer, TK pipe. Line homo mixer (Tokushu Kika Kogyo Co., Ltd.), Michaloajitar (Takasaki Seisakusho), etc.

Known resins can be used as the shell material of the microcapsule toner of the present invention, such as polystyrene, polyp-chlorostyrene, monopolymers of styrene and substituted products thereof such as polyvinyltoluene, and styrene-p-chlorostyrene. copolymer, styrene-propylene copolymer, nutyrene-vinyltoluene copolymer, styrene-vinylna 2
Talene copolymer, Nuterene-methyl acrylate copolymer, Nuterene-ethyl acrylate copolymer, Styrene-butyl acrylate copolymer, 7-terene monooctyl acrylate copolymer, Styrene-methyl methacrylate copolymer Copolymer, nutyrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, nuterene-α chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, nuterene-vinyl methyl ether copolymer, Nutylene-vinylethyl ether copolymer, nutylene-hinyl methyl ketone copolymer, nutylene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-
Maleic acid copolymer, Stereph-ma L/In m:cy
Styrenic copolymers such as -f-co-merized, I-rimether methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin,
Terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, urea resins, melamine resins, etc. can be used alone or in combination.

Moreover, a known method is applied as the microencapsulation method. For example, fugly drying method, submerged drying method,
Phase separation methods, 1n-situ polymerization methods, etc. can be used, and a multilayer shell structure may be provided in order to provide the toner of the present invention with insulation properties and appropriate triboelectric charging properties.

Further, the pressure fixable microcapsule toner of the present invention can contain various dyes and pigments and magnetic powder, and can be contained in either one or both of the core material and the shell material.

Furthermore, the toner of the present invention is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite powder, etc., if necessary, and used as a developer for electrical latent images. It can also be used in combination with hydrophobic colloidal silica fine powder for the purpose of improving the free-flowing property of the powder, and abrasive fine particles such as cerium oxide for preventing toner adhesion.

The toner according to the present invention prepared in this manner has a significant feature of having a uniform particle size distribution and a completely spherical shape as described above. For this reason, the powder has excellent flow characteristics and is easy to handle. Furthermore, it has particularly excellent development characteristics due to encapsulation, and is extremely stable in long-term environmental storage.

In addition, since it has particularly excellent particle size distribution characteristics, even when it is coated with a resin and encapsulated in microcapsules, it can be coated uniformly throughout, and a toner with particularly excellent stability can be obtained.

Example 1 Paraffin with a melting point of 70°C 100 parts Riesle 40
10 parts of 0R Dodecylamine 0.5 parts The above mixture was heated and melted and kneaded.

2 again! 101 Aerozi120 in a glass container
Take 0 and add 50011 liters of water. This was heated to 95° C. while stirring at 200 ORPM using a TK homomixer. Add the above mixture here, and then add 6000 R.
The rotation speed was increased to PM, and stirring was continued for 90 minutes. Next, the dispersion was dispersed in cold water and then over-dried to obtain a fine powder. After that, it was dispersed in a 5-xylene solution of styrene-butyl acrylate resin, and the surface was coated with the resin using a Nugre dryer. The obtained powder had extremely good fluidity. This fine powder 10
To 0 part, 0.6 part of superhydrophobic colloidal silica was added and stirred to prepare a developer.

2 Paraffin with a melting point of 75°C 80 parts Polyethylene with a melting point of 95°C 2011t Magnetite 5
0 parts dibutylamine 0.5 parts Heat and melt-knead the above ingredients.

Also, 51 parts of Aerozil 200 and 4 parts of water in a glass container. OOml was added and micronization was performed in the same manner as above.

The obtained fine particles were dispersed in DMF water in which nutylene/diethylamine ethyl methacrylate (5 parts) was dissolved, and then the surfaces of the fine particles were coated with a resin by a phase separation method.

The mixture was then mixed with hydrophobic fine particulate silica to form a developer, and when this was used to develop a photoconductor having a positive electrostatic latent image, extremely clear image lines were obtained. Next, this original image was transferred to paper and passed through a fixing machine with a linear pressure of 151 y/crn, whereupon it was fixed on the paper.

Claims (1)

[Claims] 1. A raw material mixture of a binder resin containing a compound having a hydrocarbon chain and a coloring material is melt-mixed, and then suspended and dispersed using a dispersion stabilizer consisting of a finely powdered inorganic compound that is poorly soluble in water. Microcapsule toner is made by coating the surface of particles produced by this process with resin. 2. Particles produced by mixing a raw material mixture of a binder resin containing a compound having a hydrocarbon chain and a coloring material and suspending and dispersing the mixture in hot water using a dispersant. In combination with a dispersant, the raw material mixture is cationically charged or ia () when a cationic compound or a water-soluble organic amine compound is added in water.
b) The inorganic dispersant is anionically charged by the addition of an anionic compound, and the inorganic dispersant has a charge opposite to that of the raw material mixture particles in water, and the surface of the phase mixture particles is charged with the inorganic dispersant. Particles having a uniform particle size distribution that are firmly bonded to the above-mentioned inorganic dispersant through ionic bonds around the material mixture obtained by suspending them in a uniformly coated state, and further coating the surface with a resin. Microcapsule toner made of