JPH03126041A - Microencapsulated toner and its manufacture - Google Patents

Abstract

PURPOSE:To ensure good fixability in combination to good fixability even at the time of repeated uses and good storage stability for a long time by dissolving or dispersing a main resin for outer shells and a polymer having a long ethylenic main chain and acid anhydride or its derivative as branches in a resin solution. CONSTITUTION:The outer shells are formed by dissolving and dispersing the resin for the outer shells into a good solvent and dispersing as a core material the polymer having a long ethylenic main chain and acid anhydride or its derivative as branches and adding a poor solvent to cause phase separation. At that time, the acid anhydride is partially or wholly hydrolyzed to open its ring for use in capsulation, thus permitting the obtained microencapsulated toner to be good in fixability, superior in durability, storage stability, environment stability, development characteristics, and to prevent melt attaching to and staining of a developing sleeve, a photosensitive drum, carriers, and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a microcapsule toner used in electrophotography, electrostatic printing, 6ft air recording, etc., and a method for producing the same.

[Prior Art] Conventionally, as an electrophotographic method, U.S. Patent No. 2.297°69
1 specification, Japanese Patent Publication No. 42-23910 (U.S. Patent No. 3,6 [i5,383 specification)], and Japanese Patent Publication No. 1977-23910 (US Patent No. 3,6 [i5,383 specification)]
24748 (U.S. Pat. No. 4,071,361), etc., many methods are known. An electrical latent image is formed on a photoreceptor by a method, and then the latent image is developed using toner, and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by various methods to make a copy. A method of obtaining something is taken.

BACKGROUND OF THE INVENTION As electrophotographic applied technology has become more versatile in recent years, many technological developments have continued to be made in accordance with the purpose with respect to developers for forming copied images. Toner is a powder that forms images, but in order to form images accurately, toner particles must have many functions. For example, charging properties, 1li2 transfer properties, fixing properties, storage properties, etc. Generally speaking, there is no substance that satisfies all of these requirements, and toners are usually prepared as a mixture of various materials. - The manufacturing method of toner is as follows: binder resin to fix it on the transfer material, various coloring agents to give the toner color, charge control agent to impart charge to particles, and patent application Publication No. 54-42141, JP-A-55-18656
In the so-called one-component development method as shown in the publication, various magnetic materials are used to impart transportability to the toner itself, and a release agent and a fluidity imparting agent are also dry-mixed as necessary. After that, the mixture is uniformly kneaded using a general-purpose kneading device such as a roll mill or an extruder while applying heat, and after cooling, it is pulverized using various types of pulverizing devices such as a speed mill or jet mill. fi
By classifying the particles using an llffi force classifier, the particle size can be adjusted to the size required for toner. If necessary, a fluidizing agent, a lubricant, etc. are dry-mixed into the toner. When used in a so-called two-component development method, the toner is mixed with various magnetic carriers and then used for image formation.

One such toner particle is U.S. Patent No. 4.01.
6,099, US Pat. No. 3,788,994, etc., a particle form called microcapsule toner has been proposed. This is also called a functionally separated toner. In other words, it is a toner that has a structure in which a core material particle called a core that has fixing properties and conveyance properties is surrounded by an outer wall made of a harder material that has an f-electrification function. It also has a protective role that eliminates the problems of materials and soft substances that work in the environment.

That is, for example, in a pressure fixing toner, it is preferable that the binding material be softer in terms of fixability. However, such soft materials have poor storage stability and may cause fusion phenomena within the developing device or on the surface of the photoreceptor. By surrounding the core material containing this soft material with an outer wall made of a harder material, these contradictory properties can be resolved.

Many proposals regarding such microcapsule toner have been made. For example, from a theoretical standpoint, any material composition can be considered, and methods for producing microcapsule toner include spray drying, interfacial polymerization, coacervation, phase separation, 1n-situ polymerization, and dry capsules. Various methods are known.

However, even if a material with a desirable function is used for boat fishing and the various methods described above are used, a microcapsule toner having a desirable performance cannot be easily obtained. In many cases, the formation of the outer wall is incomplete, or the adhesion between the core material and the outer wall material is incomplete, causing the outer wall to peel off due to mechanical force or toner particles to coalesce. There's a problem.

If the core material is exposed, fusion may occur on the developing sleeve or photosensitive drum because the core material is soft.
This decrease in fluidity may result in insufficient toner transport, and may cause a decrease in charging performance, storage stability, and durability. In addition, if toner particles coalesce, uniform IP charge may not be generated, resulting in poor developing performance, poor applicability to the developing sleeve, or the coalescence may be destroyed by agitation in the developing device, resulting in a defective film. The same phenomenon occurs when toner particles are retained and the core material is exposed.

Among the various encapsulation methods mentioned above, Japanese Patent Application Laid-Open No. 58-1548
By using a phase separation method as proposed in Japanese Patent No. 52 and Japanese Patent No. 59-8294.2, it is easy to obtain microcapsule particles with sufficient outer shell formation.

However, the problem of particle coalescence and the existence of so-called free shells, in which the shell material resin exists as small particles that do not wrap around the core, remain.If such free shells exist, fluidity decreases and image density decreases. , which tends to cause image unevenness (unevenness on the developing sleeve). In addition, such free shells sometimes form agglomerates and adhere to the toner, so that they may not be removed by a so-called classification process.

[Problems to be Solved by the Invention] An object of the present invention is to provide a microcapsule toner that solves the various drawbacks that are common to microcapsule toners as described above.

More specifically, it is an object of the present invention to provide a microcapsule toner that has good fixing properties even on plain paper, and has both good fixing properties, durability against repeated copying, and good long-term storage stability. It is something.

Another object of the present invention is to provide a microcapsule toner that does not cause fusion or contamination on a developing sleeve, photosensitive drum, carrier, or the like.

Still another object of the present invention is to provide a microcapsule toner which has toner particles having excellent charging characteristics, shows little change in image density even after repeated copying, and does not cause image stains such as fog or blotting.

A further object of the present invention is to have the above-mentioned excellent performance,
No incomplete membranes, no damage to the outer shell even by external physical or mechanical forces, no coalescing particles, no free shells, uniformly covered with the outer shell. The present invention provides a method for producing a microcapsule toner.

[Means and effects for solving the problems] The present invention provides a microcapsule toner comprising a core material that is solid at room temperature and an outer shell surrounding the core material, the outer shell comprising: (i) a resin in a good solvent; It is formed by dispersing the core material in a resin solution in which the core material is dissolved and dispersed, and then adding a poor solvent to cause phase separation. It is made by dissolving and dispersing an ethylene skeleton polymer having a chain alkyl group and an acid anhydride or a derivative thereof as branches, and (2) partially or completely ring-opening the acid anhydride moiety in the ethylene skeleton polymer to form encapsulation. The present invention relates to a microcapsule toner characterized by being formed by using the microcapsule toner.

Furthermore, a core material that is solid at room temperature is dispersed in a resin solution in which a resin is dissolved and dispersed in a good solvent, and then a poor solvent is added to cause phase separation to form an outer shell around the core material. In the method for producing a microcapsule toner, a main resin for the outer shell and an ethylene skeleton polymer having a long-chain alkyl group and an acid anhydride or a derivative thereof as branches are dissolved and dispersed in the resin solution, and The present invention relates to a method for producing a microcapsule toner, which is characterized in that the acid anhydride moiety in the ethylene skeleton polymer is partially or completely ring-opened.

Here, a microcapsule toner in which an outer shell is formed from a resin solution to which an acid is added is preferable, and a method for producing a microcapsule toner in which an outer shell is formed after an acid is added to a resin solution is preferable. , the ring-opening index determined by infrared absorption analysis of the acid anhydride moiety in the ethylene skeleton polymer is 0.
It is preferably 4 or more, and the ring opening index determined by infrared absorption analysis of the acid anhydride moiety in the ethylene skeleton polymer is 0.
A more preferable microcapsule toner can be obtained by a method for producing a microcapsule toner using a microcapsule toner having a particle size of 4 or more.

In the phase separation method used for the microcapsule toner of the present invention, it has already been found that the presence of a so-called surfactant at the time of encapsulation is effective as a method for preventing capsule coalescence. In this case, it is often difficult for the shell material to adhere to the core material, and many particles consisting only of the shell material are generated, which often has a negative effect on fluidity, etc. Furthermore, the microcapsule toner produced by this method is highly hygroscopic, which adversely affects chargeability, developability, and the like.

As a method to solve this problem, Japanese Patent Application Laid-Open No. 60-69654
There is a method using an ethylene skeleton polymer having an α-olefin and an acid anhydride or its reader as branches, as disclosed in Japanese Patent Application Laid-Open No. 61-099152. As described in the publication, this method is effective in preventing coalescence of microcapsules during encapsulation. However, since this substance has an acid anhydride group in its molecular center or side chain, it is not preferable to use too much of it from the viewpoint of moisture adsorption. In addition, since the substance itself tends to be negatively chargeable, for example, when it is desired to charge the capsule toner as a positive toner, the charges may cancel out or the chargeability may become unstable. It is not preferable to use a large amount.

As a result of further studies from these points of view, we found that the microcapsule toner produced by using the ethylene skeleton polymer in combination with an acid has excellent image properties such as fogging, fusion, and unevenness, and can provide sufficient image density. It became something that could be done. However, as a result of further studies regarding environmental stability and high-volume durability, we found that by opening the acid anhydride moiety in the ethylene skeleton polymer and using it, we found that it has good environmental stability and long life. A microcapsule toner that exhibits durability and has sufficient image density and quality has been obtained.

The ethylene skeleton polymer (ethylene skeleton polymer having a long chain alkyl group and an acid anhydride or its 8 conductors as branches) used in the present invention is disclosed in JP-A No. 60-69659,
As shown in Japanese Patent Application Laid-Open No. 61-099152, -
For boat fishing, α-olefin-maleic anhydride copolymer (I), polyalkenylsuccinic acid polymer (11), etc. having the following structures are easily available.

The amount of these substances added varies depending on the length of the alkyl group, the ratio of the ring-opened portion, the type of resin for the outer shell, etc.; The appropriate amount to be added, which is preferable in terms of the performance of the capsule toner, can be determined experimentally.

(Space below) (1) (I!) Generally, it is difficult to obtain the compound (■') by the reaction of ring-opened maleic acid and α-olefin, but it is difficult to obtain the compound (■') by copolymerization of maleic anhydride and α-olefin. ), which is ring-opened and used.

As a ring-opening method, the compound is heated under high temperature and high humidity (ex
, 45° C., 80% RH), dispersing it in a solvent and heating it to react with moisture in the solvent to open the ring, but the production method is not particularly limited.

Indicators for measuring the degree of ring opening (ring opening index) include methods such as infrared absorption, acid value measurement, and saponification value measurement, but from the viewpoint of simplicity and reproducibility, red A preferred method is to use external absorption analysis to determine the ratio of absorption peaks.

This method is based on the height (hl) above the baseline of the infrared absorption peak of the C-0 stretching vibration near 1850 cm-', which is characteristic of acid anhydrides, and the 172
Peak height of C-O stretching vibration near 0 cm-' (hl)
The ratio is called the ring-opening index (h+/hz). A schematic diagram of the calculation method and an example of this method is shown in FIG. In the present invention, infrared absorption analysis was performed using a Perkin-Elmer FT-IR1600 model. The measurement method used the KBr tablet method. After mixing B with a certain amount of ethylene skeleton polymer,
This was done by looking at infrared absorption up to -'.

In the present invention, the ring opening index (h
+/ha) is preferably 0.4 or more, more preferably 0
．． It is 5 or more.

In the present invention, it is preferable that the outer shell is formed from a resin solution to which an acid is added. By adding acid, due to the synergistic effect with the ethylene skeleton polymer, microcapsule particles are formed in which the shell material is uniformly formed on the core material, and the particles do not coalesce and the generation of free shells is suppressed. can get.

As the acid used in the present invention, inorganic acids such as hydrochloric acid and sulfuric acid, and organic acids such as formic acid and acetic acid can be used.
A weak acid such as acetic acid is preferably used because the shell formation state can be easily adjusted.

The amount of acid added varies depending on the type of acid used, the shell material resin, or the ethylene skeleton polymer, but is generally 2 times the weight or less of the total amount of the outer shell resin. The amount used is usually determined experimentally.

Generally known materials can be used as the binding material in the core material of the present invention, but soft solids are particularly suitable for pressure fixing or low temperature fixing toners commonly used as microcapsule toners. A solid material or a low softening point solid material is preferably used. Such substances include waxes (beeswax, carnauba wax, paraffin wax, microcrystalline wax, etc.), higher fatty acids (stearic acid, palmitic acid, lauric acid, etc.), higher fatty acid metal salts (aluminum stearate, stearic acid, etc.). Lead, barium stearate, magnesium stearate, zinc stearate, zinc palmitate, etc.), higher fatty acid metal salts (methyl hydroxystearate, glycerol monohydroxystearate, etc.), polyolefins (low molecular weight polyethylene.

low molecular weight polypropylene, polyethylene oxide, polyisobutylene, polytetrafluoroethylene, etc.), olefin copolymers (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene- methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer resin, etc.), styrenic resin (low molecular weight polystyrene, styrene-butadiene copolymer (
(weight ratio of 5 to 30:95 to 7 o), styrene-acrylic compound copolymer, etc.), epoxy resin, polyester resin (acid value of 1 o or less), rubbers (isobutylene rubber, nitrile rubber, chlorinated rubber, etc.), Examples include polyvinylpyrrolidone, polyamide, coumaron-indene resin, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, and silicone resin, and these can be used alone or in combination.

The core material of the capsule toner of the present invention generally contains various dyes and pigments as colorants. Examples of such dyes and pigments include carbon black, nigrosine dye,
Lamp Black, Sudan Black SM, First Niro 01 Benzidine Niro Pigment Niro India First Orange, Irgazine Red, Balanitroaniline Red, Toluidine Red, Carmine F
B, Permanent Bordeaux FRR, Pigment Orange R, Lysole Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Fuclocyanine Blue Pigment Blue, Prilliant Green B, Phthalocyanine Green, Oil Yellow GG, Zapon Fast Yellow C
GG, Kayaset Y 963, Kayasera 1-YG,
Sumiblast Yellow GG, Zapon Fast Orange RR, Oil Scarlet, Sumiblast Orange G
, Orazole Brown B, Pomelo First Scarlet CG, Eisenspiron Red BEI+, Oil Pink OP, etc. can be applied. These colorants are generally used to obtain capsule toners for two-component developers, and are preferably added in an amount of 0.5 to 20% by weight based on the core material binder.

Further, in order to use the capsule toner of the present invention as a one-component magnetic toner, magnetic powder may be contained in the core material.

As such magnetic powder, substances that are magnetized by being placed in a magnetic field are used, such as powders of ferromagnetic metals such as iron, cobalt, and nickel, or magnetite, hematite,
There are alloys and compounds such as ferrite. The content of this magnetic powder is preferably 15 to 70% by weight based on the weight of the toner.

Such a magnetic material may be treated with a known coupling agent in order to improve its compatibility with the resin or the dispersibility of the magnetic material.

Such coupling agents include silane coupling agents,
Examples include titanate coupling agents, aluminum coupling agents, zirconium coupling agents, etc., and they are preferably used in a ratio of 0.1 to 10fii% to the magnetic material.

Furthermore, various mold release agents may be used in the core material, and examples of such mold release agents include polyfluorinated ethylene, fluororesin, fluorinated carbon oil, silicone oil, low molecular weight polyethylene,
Examples include low molecular weight polypropylene, and the amount is 0.1 to 20% by weight, preferably 0.5 to 10% by weight based on the binder resin.
used at a rate of

Generally known resins are used as the resin for the outer shell of the microcapsule toner of the present invention, but in particular, minus OPC
When applied to a copying machine using a drum and used as a positive toner, good positive chargeability can be obtained by using a resin containing nitrogen atoms in its structure.

Monomers constituting such a resin include N, N-
Amino group-containing vinyl monomers such as dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-dipropylaminoethyl methacrylate, N,N-dimethylaminopropylacrylamide; acrylamide , methacrylamide, acrylonitrile,
Acrylic acid or methacrylic acid conductors such as methacrylonitrile, N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylpyrrolidone, N-vinylimidazole; 4-vinylimidazole, l
- Vinyl compounds having a nitrogen-containing ring in the side chain, such as vinylpyrrole and 4-vinylpyridine, etc. Such monomers can be used as homopolymers, copolymers, or copolymers with other monomers shown below.

Other monomers for forming the outer shell include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-methoxystyrene, and p-methylstyrene.
-Phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene% 9-n-butylstyrene, p-tert
-butylstyrene, p-n-hexylstyrene, p-n
-octylstyrene, p-n-nonylstyrene, p-n
- Styrenic mercury consisting of styrene and derivatives thereof such as decylstyrene and p-n-dodecylstyrene;
Ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl cotton; Vinyl esters such as vinyl acetate, vinyl propionate, and vinyl benzoate Class; methyl methacrylate,
α-methylene aliphatic monomers such as ethyl methacrylate, propyl methacrylate, 1ln-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, etc. Carboxylic acid esters; α-methyl chloromethacrylate,
Maleic acid, maleic ester; methyl acrylate,
Acrylics such as ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate. Acid esters; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; 1! It can be used as a copolymer of the above. Furthermore, two or more types of resins may be blended and used for the outer shell.

The ethylene skeleton polymer of the present invention helps to form a uniform capsule shell, but especially when the nitrogen-containing resin compound is used as the shell material, it not only forms a uniform capsule shell but also helps toner particles. Improves the positive charging property of This may be considered to be because the presence of the carboxylic acid group increases the positive charge of the nitrogen atoms in the resin for the outer shell, but this reason is not the purpose of the present invention.

The outer shell of the microcapsule toner of the present invention contains pigments such as carbon black and phthalocyanine, charge control agents, magnetic substances such as ferrite, magnetite, copper, cobalt, and nickel, tin oxide, titanium oxide, and zinc oxide, as required. Conductive fine powders such as silica, fluidizing agents such as alumina, abrasives such as cerium oxide, strontium titanate,
Other layer agents, control agents, etc. may also be contained.

An example of an encapsulation method preferably used in the present invention is to dissolve and disperse the resin forming the outer shell and the ethylene skeleton polymer used in the present invention in a good solvent, then add an acid as necessary, and then Particles serving as the core material are uniformly dispersed in the solution.

While maintaining this solution at an appropriate temperature, a poor solvent that is miscible with the good solvent is added to deposit the resin in droplets around the core material, and then the droplets coalesce to smooth and solidify. .

The encapsulated toner is easily separated by a method such as centrifugation or pressure filtration.Then, the microcapsule toner is washed if necessary and dried to serve as a microcapsule toner.The separated solvent is separated by a method such as distillation. collected and reused.

When performing microencapsulation using the above-mentioned good solvent and poor solvent, it is preferable to perform the encapsulation at a low temperature such as -5°C to -35°C. By performing the process at such a low temperature, it is possible to prevent the solvent from volatilizing, to prevent the core material from eluting into the solvent, and to adjust the viscosity of the system during encapsulation, which results in the coalescence of toners and the release of toner particles. It can prevent shell formation and provide high quality toner.

As a method for preparing particles of the core material used in the present invention, conventionally known particle forming methods such as a pulverization method, a suspension method, and a polymerization method are used. In particular, when a wax-like substance is mainly used as the core material for pressure fixing, suspension granulation in water as shown in JP-A-59-127061, U.S. Patent No. 567.498, etc. is recommended. Suitable for use. This method mainly uses water as a dispersion medium in a container equipped with a stirring device, and a molten mixture of the core material composition is introduced into the container to turn the dispersoid into fine particles. In this method, a poorly water-soluble inorganic fine powder having a positive or negative charge is dispersed in a dispersion medium, and a substance having a charge of opposite polarity to that of the inorganic fine powder is contained in the dispersoid. This is a method of suspending and atomizing particles and stabilizing them. The particles made by this method have a uniform particle size,
In addition, since it is substantially spherical, it has excellent fluidity and dispersibility.
This has the advantage that it is easy to form a uniform film in the subsequent encapsulation process.

The microcapsule toner of the present invention is used as a developer after being mixed with a fluidity improver such as colloidal silica, a lubricant, an abrasive, a charge control agent, etc., depending on the case.

The microcapsule toner of the present invention can flexibly respond to the performance required of the toner of the electrophotographic main body device to which it is applied. This can be controlled almost arbitrarily by adjusting the physical properties of the toner such as the amount of charge and fluidity of the toner according to the present invention, as well as the ratio of the amount of ethylene skeleton polymer added and the amount of acid added, the encapsulation temperature, etc. Because you can. That is, the present invention can provide a toner that meets the requirements of the main body development process, transfer process, and fixing process, that is, the characteristics of the microcapsule toner are appropriately controlled.

The present invention will be described in more detail below with reference to specific examples, but the present invention is not restricted in any way by these examples.

[Example] Preparation of core material> After weighing each of the above-mentioned materials, they were melted and dispersed at 90° C. for 1 hour using an attritor (manufactured by Mitsui Miike Co., Ltd.) filled with stainless steel poles to obtain a molten mixture of dispersoids. This was taken out into a stainless steel container and kept at 120° C. with stirring.

Separately, 18j2 of water was put into a 20e Ajihomo mixer (manufactured by Tokushu Kika Co., Ltd.) and stirred and heated until the temperature reached 87°C. 84 g of colloidal silica, Aerosil #300 (manufactured by Nippon Aerosil Co., Ltd.), was added to this water and uniformly dispersed by stirring. Homomixer rotation speed to 80
The molten mixture was poured into an Ajihomo mixer rotated at 00r, p, a+ for 30 seconds, and the molten mixture was dispersed in water and atomized. After 10 minutes had passed after the completion of the charging, the mixed liquid containing the suspended and dispersed dispersoid particles was discharged into a previously prepared plastic container containing approximately 30 kg of crushed ice, and was rapidly cooled and solidified. Substantially spherical core particles were obtained. After the slurry in the plastic container was stirred with a propeller mixer and returned to room temperature, 400 g of sodium hydroxide was added and stirred for one day and night to dissolve the colloidal silica. The particle size distribution at this time was measured using a Coulter Counter (Model T^-II manufactured by Coulter Electronic Co., Ltd.) using a 100 μm diameter aperture, and the number average diameter (hereinafter abbreviated as dn) d, = 7.89 ( μm), volume average particle diameter (hereinafter abbreviated as dv') dv = 10.05 (μml 8.
Number percent of particles of 35 μ■ or less (hereinafter 6.351
)6.35↓=28.7 (%), 20.2
This alkaline dispersion, whose weight percentage of particles larger than μm (hereinafter abbreviated as 20.2↑) was 20.2↑=0 (%), was classified in a liquid state using a wet cyclone classifier (manufactured by Oishi Kikai Co., Ltd.). , d,=8.08 (μm), dv=
10.09 (μm).

6.35↓=20.3(%), zo, 2t=o
(%) of particles, this dispersion was filtered using a centrifugal separator, re-slurried in 30 ft of water, washed with water with stirring, and filtered using a centrifugal filter again.
Drying was performed using a ventilation dryer. Colloidal silica 1. OM amount percentage was determined by Henschel mixer FMIOB at 3000 r, p, m,
The mixture was stirred and mixed for 1 minute to adhere to the surface of the core material. FE-
When observed by 5EM, there were almost no free silica particles. This particle was used as a core material in the following example of a capsule toner.

An α-octadecene-maleic anhydride copolymer (Mw=about 50,000) was crushed in a mortar to form a fine powder.

After this fine powder was left in a constant temperature bath at 45°C and 75% R)I for 3 days, the ring opening index (h2/h, l) was measured with an FT-IR manufactured by Perkin-Elmer and found to be 2.12. there were.

The above components were stirred and mixed in a stainless steel container purged with N2 to prepare a resin solution. A homomixer was attached to a stainless steel reaction tank (capacity: 15JZ) with a small refrigerant jacket, and a lid was attached to create a device capable of N2 purging, which was used as an encapsulation reaction tank.

5.6 kg of the above solution was put into this reaction tank, and under stirring -2
After cooling to 3° C., 120 g of acetic acid was added and stirred for 5 minutes. Here, the core material particles 2, 0 kg were added, and 10
The mixture was stirred for a minute to disperse it, and the temperature of the solution in the reaction tank was adjusted to -23°C. The operations up to this point were performed while flowing N2 into the reaction tank.

Next, dropwise addition of ice-cooled water at 0.5° C. was started at a rate of 15 g/min. The solution temperature in the reaction tank during dropping is ±
The temperature was maintained within 0.5°C. When the dispersion was checked after 60 minutes, the resin had completely precipitated and disappeared. After cold water was further added dropwise at a rate of 60 g/win for 30 minutes, the dispersion was taken out from the reaction tank, and the solid content and solvent were separated using a centrifugal filter. At this time, the solid content was thoroughly showered with water. This solid content was further reslurried in 30% water, washed with water, further filtered with a centrifugal filter, showered, and drained.
It was dried in a ventilation dryer. 14 g of hydrophobic colloidal silica was externally added to 1 kg of the dried microcapsule particles using a Henschel mixer to prepare a microcapsule toner. When the particle size distribution of this microcapsule toner was measured, it was found to be d, -8,87 (μm), dv
= 11.55 (μm), 6.35↓ = 15.5
(%) 20.21; 0.8 (%). When this particle was observed using FE-SEM, it was found to be a confetti-like particle with spherical irregularities on the surface, but the irregularities existed uniformly on the particle surface, and the surface was smooth and was evenly covered with shell material. It was observed that this was happening. Furthermore, no free shell was observed, and no appearance of the core surface being exposed was observed.

This toner was mixed with a carrier at a T/C ratio of 10/90 using a Canon tribo measuring device.
, when measured under 65% RH, 7,9 (μc/g)
Met.

Next, image evaluation was performed using this toner.

The copying machine used was a modified Canon NP-5540 (
This was done using a rigid roller (instead of a heated roller constant applicator). As a result of running 50,000 sheets in a normal environment at 23° C. and 65% R), good images with no fog or unevenness were obtained. The average image density up to 50,000 sheets was 1.62, and the image density drop at the start of the morning operation and at the time of toner replenishment operation was also within 0.1. Furthermore, no adhesion to the drum, developing sleeve, etc. was observed.

Next, image evaluation was performed in a low temperature, low humidity environment of 15° C. and 10% RH. As a result of a durability test of 20,000 sheets, the image density during durability was as high as 1.60 to 1.70, and there was almost no decrease in image density during toner replenishment operations. Further, there was no occurrence of image stains due to fog or unevenness on the developing sleeve. Another 33℃.

A drawing test was conducted under high temperature and high humidity conditions of 85% RH, and the image density was as high as 1.40-1.60, and the image density at the start of operation in the morning was also over 1.40. Furthermore, there was almost no decrease in image density due to durability, and toner fusion to the photosensitive drum and developing sleeve did not occur until 20,000 sheets were printed. We conducted a rubbing fixing test on image samples in each of these environments using Silbon paper (applying a load of 50 g per 1 cm2, rubbing 5 times back and forth to see how the toner peels off), and the results showed that the density reduction rate was within 8% in all cases. Ta.

The fine powder of α-octadecene-maleic anhydride copolymer used in Example 1 was placed in a constant temperature bath at 45°C and 85% R) for 3 hours.
．． After standing for 5 days, the ring opening index (h,
/l++) was measured and found to be 3.15.

Using this, a resin solution was prepared using the same blending ratio and method as in Example 1. Furthermore, a microcapsule toner was produced using the same method. However, the capsule reaction temperature is -2
The test was carried out at 2° C. and 114 g of acetic acid. The particle size distribution after external addition of hydrophobic colloidal silica is d. = 8.94 (μm
), d, = 11.63 (μm).

635↓=13.9 (%), 20.2t=1
．． l (%). Also, the tribo is 8.4 (μc/
g).

When this microcapsule particle was observed with FE-5EM, it showed a good morphology as in Example 1. Furthermore, in the durability test, the average image density under normal environment was as high as 1.65, and no particularly problematic images were obtained. Furthermore, almost the same results as in Example 1 were obtained in the low temperature, low humidity and high temperature and high temperature tests.

Comparative Example 1 A sample of the α-octadecene-maleic anhydride co-molecular fine powder used in Example 1 left in an environment of 75% R)I at 23°C for one day was measured by FT-IH.
Absorption due to carboxylic acid groups was only visible as a slight shoulder. A portion of this shoulder was taken as a peak and the peak height (h2) was determined, and the ring opening index (h2/h+) was determined to be 0.37.

Using this, a resin solution was prepared using the same blending ratio and method as in Example 1. Further, a microcapsule toner was produced in the same manner as in Example 1. The reaction temperature and amount of acetic acid added were also the same as in Example 1. The particle size distribution after external addition of hydrophobic colloidal silica is dn=7.76 (μm0),
dv=10.71 (μm), 6.35↓=42.
3 (%'), 20.2t = 3.4 (%). Moreover, tribo was 11.4 (μc/g).

When this microcapsule particle was observed with FE-5EM, many spherical free shells were observed. These free shells are droplets generated by phase separation during encapsulation that remain without adhering to the core material, some as aggregates of free shells, and others as a combination of free shells and toner. It existed as an aggregate. Even if the amount of α-octadecene-maleic anhydride copolymer added, the amount of acid added, the temperature, etc. were changed, only capsule toners with the same form could be obtained.

A durability test was also conducted on this toner.

As a result of the Yamada test in a normal environment, the initial image density was low and was less than 1.00. 50 more
The image density rose to around 1.50 at about 0 sheets, but then gradually decreased, and at about 4000 sheets, it was only 1.15, resulting in an image with a lot of shaky and rough spots. Furthermore, under low temperature and low humidity conditions, the image density did not rise above 1.20. Furthermore, after about 1,500 copies, spot-like unevenness occurred on the developing sleeve and appeared on the actual printed image. Furthermore, under high temperature and high humidity conditions, cleaning failure occurred after 3,000 sheets, and drum fusion occurred after 3,500 sheets. The image density was approximately 1.30 to 1.40.

When the Le301 α-octadecene-maleic anhydride copolymer was directly subjected to 1-IR, the carboxylic acid peak was indistinguishable, suggesting that almost no ring opening had occurred.

Using this, a resin solution was prepared using the same blending ratio and method as in Example 1. Further, a microcapsule toner was produced in the same manner as in Example 1.

When this sample was observed with FE-5EM, the same morphology as in Comparative Example 1 was observed.

A copolymer of a mixture of α-olefins having 16 and 18 carbon atoms and maleic anhydride (molecular weight Mw = about 15, .000
) was used to produce a toner.

The copolymer was crushed in a mortar, and the resulting fine powder was heated at 45°C.
A copolymer sample having a ring opening index (hz/h+) of 1.45 as measured by FT-IR measurement was obtained by leaving it in a constant temperature bath at 75% RH for 2 days.

A resin solution was prepared using the above components in the same manner as in Example 1. Furthermore, microcapsule particles were produced in the same manner as in Example 1 using 5.6 kg of this solution, 2 kg of core material, and 0 kg. The encapsulation temperature at this time was -26°C, and the amount of acetic acid added was 106.5 g. 10 g of hydrophobic colloidal silica was externally added to 1 kg of microcapsule particles after dry smoking using a Henschel mixer to prepare a microcapsule toner. The particle size distribution of this microcapsule toner is dn=8.56 (μml, dv=
LL, 48 (gm), 6.351 = 16.3
(%), 20.21=0.6 (%). When this particle was observed under FE-50,000M, it was observed that it had confetti-like irregularities and was coated uniformly, as in Example 1. The triboelectricity of this toner was 8.2 (μc/g).

Next, image evaluation was performed using this toner.

The copying machine used was a modified Canon NP-3525 machine (
(runner roller) was used. We conducted a durability test of 30,000 sheets in a normal environment, and the result was 1.5 from the start.
An image density of 0 or more is obtained, and the average image density during durability is 1
．． It was 64. At the start of operation in the morning, the image density drop during toner replenishment was about 0.1, and no long-term density drop occurred. Further, good images were obtained without fogging and with no cleaning defects. Furthermore, even in a low-temperature, low-humidity environment, the image density was as high as 1.60 to 1.70, and no unevenness or fogging occurred on the developing sleeve. Furthermore, the image density was 1.40 to 1.60 even under high temperature and high humidity conditions, and the average image density decrease within 0.10 after 30,000 sheets were printed. Further, no various fusion phenomena occurred. As a result of testing the running properties of the image samples in each environment, the density reduction rate was all within 9%, which was good.

Example 4 The fine powder of the α-olefin-maleic anhydride copolymer used in Example 3 was left in a constant temperature bath at 45°C and 85% RH for 6 days, and the ring opening index (h2/hl) was 3.35. Got the sample.

A resin solution similar to that in Example 3 was prepared using this sample. Further, a microcapsule toner was produced in the same manner as in Example 3. However, the encapsulation temperature at this time was -25°C, and the amount of acetic acid added was 10 [i, 5 g]. The particle size distribution of this microcapsule toner is dn=8
．． 66 (μm), dv=11.53 (μm).

6.351= 13.8 (%), 20.2↑=0
．． 7 (%). Tribo is 9.0 (μc/g)
Met. When this particle was observed with FE-50,000M, it had almost the same morphology as Example 3, and almost no free shells or coalescence of particles was observed. Zarani NP-35
As a result of carrying out durability tests in various environments using a modified No. 25 machine, it showed almost the same performance as Example 3.

Comparative Example 3 When the fine powder of the α-olefin-maleic anhydride copolymer used in Example 3 was directly subjected to FT-IR, no absorption peak due to ring opening was observed.

A resin solution similar to that in Example 3 was prepared using this sample. Further, a microcapsule toner was produced in the same manner as in Example 3.

The particle size distribution of this microcapsule toner is d,=7.
85 (μm), dv=10.91 (μm), 6.
351=3.98(%), 20.21=3.2
(%)Met. Moreover, the triboelectricity is 11,5 (μc/
g). When this toner was observed using FE-50,000M, it was observed that, as in Comparative Example 1, many free shells were generated.

Using this toner, the same drawing evaluation as in Example 3 was conducted. In the normal environment, the initial image density was as low as 0.95, and after rising slowly to around 1.55, the density began to decrease from around 1,500 sheets and decreased to 1.20 at 5,000 sheets. Furthermore, the image had a lot of jittery and rough spots. A slight amount of drum fusion occurred around 10,000 sheets. Further, at low temperature and low humidity, the toner triboelectricity was high and the toner did not fall onto the developing sleeve, and the image density did not rise above 1.20. Furthermore, under high temperature and high humidity conditions, drum fusion occurred after 1000 sheets.

[Effects of the Invention] As can be seen from the examples above, the microcapsule toner of the present invention has 1) good fixing properties, excellent durability and storage stability, and 2) is suitable for use in developing sleeves, photosensitive drums, carriers, etc. It is a microcapsule toner that does not cause build-up or staining, (1) has excellent development characteristics, and (2) has excellent environmental stability.

[Brief explanation of the drawing]

FIG. 1 schematically shows a method for calculating a ring-opening index from an infrared absorption spectrum.

Claims (6)

[Claims] (1) In a microcapsule toner consisting of a core material that is solid at room temperature and an outer shell surrounding the core material, the outer shell is dissolved in a resin solution in which a resin is dissolved and dispersed in a good solvent. It is formed by dispersing the core material and then adding a poor solvent to cause phase separation. {2} The resin solution contains the main resin for the outer shell, a long chain alkyl group and an acid anhydride It is formed by dissolving and dispersing an ethylene skeleton polymer having the derivative as a branch, {3} and by partially or completely ring-opening the acid anhydride moiety in the ethylene skeleton polymer and using it for encapsulation. A microcapsule toner characterized by: (2) The microcapsule toner according to claim (1), wherein an acid is added to the resin solution. (3) The microcapsule toner according to claim (1) or (2), wherein the ring-opening index determined by infrared absorption analysis of the acid anhydride moiety in the ethylene skeleton polymer is 0.4 or more. . (4) After dispersing a core material that is solid at room temperature in a resin solution in which a resin is dissolved and dispersed in a good solvent, a poor solvent is added to cause phase separation to form an outer shell around the core material. In the method for producing a microcapsule toner, a main resin for the outer shell and an ethylene skeleton polymer having a long chain alkyl group and an acid anhydride or a derivative thereof as branches are dissolved and dispersed in the resin solution, and A method for producing a microcapsule toner, characterized in that the acid anhydride moiety in the ethylene skeleton polymer is partially or completely ring-opened. (5) The method for producing a microcapsule toner according to claim (4), wherein the outer shell is formed after the acid is added to the resin solution. (6) The microcapsule toner according to claim (4) or (5), wherein the ring-opening index determined by infrared absorption analysis of the acid anhydride moiety in the ethylene skeleton polymer is 0.4 or more. manufacturing method.