JPS58216259A - Microcapsule toner - Google Patents

Abstract

PURPOSE:To obtain a microcapsule toner having uniform grain sizes by producing said toner by an electrically emulsifying method. CONSTITUTION:A core material such as a polyester resin or the like is discharged and atomized from the end of a nozzle or disc into liquid contg. polystyrene or the like that forms a shell material under application of a high voltage. Said dispersion is further polymerized by heating or the like in a reactor, whereby a microcapsule toner is formed. Since the high voltage is applied to the core material discharged and atomized from the nozzle, the decrease in the surface tension of the material of the toner by this invention results therefrom, and consequently the toner has about 10mum particle size effective for an electrophotographic characteristic and the particles of the core material having a narrow grain size distribution are obtd. The shell material is stuck to such core material; therefore, the toner having uniform grain sizes is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for manufacturing a uniform film using an electroemulsification method. This is a method in which an image is formed on the surface of a photoconductive material using an L copying device and then developed. For example, as described in U.S. Pat. No. 2,297,691, a uniform electrostatic charge is provided on a photoconductive insulating layer, and this layer is exposed to light reflected from the original document, causing toner to deposit on the electrostatic latent image. By this, the latent image is developed. This detoning toner normally adheres selectively only to portions that retain electric charge, and is permanently fixed therein by applying pressure. In the above case, it is necessary to heat the toner to a temperature at which it melts and flows, or to pressurize the toner at a pressure that causes plastic deformation.

Conventionally, the method for producing electrophotographic developers has been to use a binder resin consisting of a solid resin or a liquid side and a solid resin, and add magnetic powder, a coloring agent, a hardening agent, and a base as necessary. The method used is to heat-melt and mix additives, etc., and then mechanically crush the mixture. However, with this method, it is very difficult to control the particle size and particle size distribution of the toner, and the particle shape inevitably becomes angular, which causes problems in flow characteristics and agglomeration. , physical properties such as stability are deteriorated, and handling is also inconvenient because a dry pulverization method is used. For example, when dry mechanical pulverization is carried out in one paste for producing toner, the following disadvantages e occur. (1
) Regarding toner production, it is necessary to crush toner materials at an economical speed, so when soft materials are used, they tend to fuse to the machine, making it difficult to crush them. For this reason, hard materials are generally used. However, toners manufactured using materials that are easily crushed encounter unexpected problems. For example, as the toner is further pulverized in the developing machine, phenomena such as dirt inside the machine, fogging of images, and smearing occur due to ultrafine toner particles. (Due to machine crushing, the buried colorant is exposed to the surface, resulting in partial non-uniformity of the fundamental charging characteristics, that is, asymmetric charge, which causes poor contrast and resolution. Furthermore, depending on the colorant, moisture absorption may occur. (3) Since amorphous toner is produced by pulverization, it is not possible to point the toner onto the photoconductive surface where the electrostatic density is at its maximum, causing background fog.

(4) Soft materials with good pressure and stability are difficult to crush because they are fused to the machine type. In order to improve the above-mentioned drawbacks of dry mechanical pulverization, it is necessary to fully promote the thermal diffusion of the Joule heat generated in the pulverization process using a medium such as water.

Microencapsulated toner is effective.

On the other hand, soft control is generally used for core materials for microcapsule toners. The following two methods are conventionally known as methods for producing microcapsule particles of uniform particle size using a soft-core material that is difficult to dry mechanically crush.

Wet pulverization method (it) Spray drying method The wet pulverization method is a method in which core particles are formed in advance in a wet system and then shells are formed subsequently or simultaneously to form microcapsules. The core material is pre-coated with relatively small particles.
The process consists of a dispersion process for dividing into F and an encapsulation process (hereinafter referred to as the second process) in which emulsification is applied (hereinafter referred to as the first process) and a shell is placed on top of the emulsification process (hereinafter referred to as the first process). At this time, in order to produce a microencapsulated toner with a uniform particle size that is effective in terms of electrophotographic properties, a large amount of emulsifier is used, and if necessary, a dispersion aid is added, and a high-speed stirrer or ultrasonic pulverizer is used. This is a step in which, after forming uniform microparticles in advance, the shell material is separated into carriers or continuously deposited and fixed on the surface of the core particles. Interfacial polymerization, phase separation, and temperature gradient precipitation methods can be used to deposit and fix the core particle onto the surface of the core particle. It is possible to strengthen chemically or physically. However, in this method, a large amount of emulsifier that acts on the atomization in the first step inevitably remains on the surface of the core material during the subsequent second step, which greatly reduces the adhesive strength of the shell material. With,
A large number of individual particles formed only from the shell material are produced as by-products, making it difficult to obtain a microencapsulated toner with desired uniform particle size and good field isolation properties.Furthermore, the residual emulsifier causes a dazzling phenomenon. It has a negative impact on electrophotographic characteristics. In addition to the above-mentioned drawbacks, in order to produce microcapsule toner by wet pulverization, there is also a problem of particle size broadening that inevitably occurs due to mechanical stirring. On the other hand, in the method of producing microcapsule particles by using the blow drying method, the base material and the shell material are kneaded in advance in the atmosphere or dispersed in a medium, and then This is a method in which the shell material is deposited on the surface of the core particle by discharging it. However, there is a tendency towards this method.

It is an object of the present invention to provide a microcapsule toner manufactured by a method that overcomes the above-mentioned drawbacks. An object of the present invention is to provide a microcapsule toner having a uniform particle size, which is obtained by discharging a core material into a medium containing a shell material while applying a high voltage.

The microcapsule toner produced in the present invention is discharged from the nozzle or the end of the disk and is applied with a high voltage to the atomized base material, which reduces the tension on the two sides of the material, resulting in effective electrophotographic properties. Core material particles having a particle size of about 10 capes and a narrow particle size distribution are produced.

As a result, microencapsulated toner particles produced by adhering the shell material to the core material can also be obtained as microencapsulated toner particles having uniform particle diameters.

Furthermore, it is an object of the present invention that the microcapsule toner obtained according to the present invention has a particle size of about 10 $, which is effective in terms of electrophotographic properties, and has a narrow particle size distribution. The present invention provides a toner that can be used as an electrophotographic toner with only a few classification operations.

It is a further object of the present invention to provide a microencapsulated toner which contains little or no emulsifier which inhibits the formation of shell materials.

A further object of the present invention is to provide a microencapsulated toner that can prevent the material from flying up by applying a voltage and has a high yield.

Its feature is that it is a microcapsule toner produced by atomizing the core component into a shell liquid when a voltage is applied, and further polymerizing the dispersion once obtained.

The base material used in the present invention can be any material that can be ejected using a nozzle or bell into a medium that depletes the shell material while applying a voltage. In general, substances that exhibit a two-liquid state or an S-turbid dispersion state are effective when discharged;
For example, polyester resin; polyester-based urethane polymer; polyester-based alkyd resin; trimellitic acid ester of polycaprolactone, rosin ester, modified rosin ester.

Polyester resins with various requirements, such as the reaction between isopropylidene diphenoxypropanol and adipic acid, and the reaction product between isoglopylidene phenoxyglobanol and sebacic acid; polyethylene wax, carnauba wax, castor wax, rice wax , Schlack wax, Zazol wax, Amide wax, Montan wax, Icrocrystalline wax.

Waxes represented by ceresin wax, paraffin wax, and osikelite; behenic acid amide, stearic acid amide, valmitic acid amide, lauric acid amide,
Erucic acid amide, plaidic acid amide, oleic acid amide, elaidic acid amide, methylene bisbehenic acid amide.

Methylenebisstearamide, methylenebisoleicamide, hexamethylenebisstearamide,
Hexamethylene bisoleic acid amide, octamethylene biserucic acid amide.

Polyamide resins represented by monoalkylolamides, polyamides produced from trimerized linoleic acid and diamines or polyamines, and reaction products of dicarboxylic acids and linear diamines; polyvinyl acetate, ethylene-vinyl acetic acid combination , polyisobutylene, polystyrene, dodecyl acrylate-styrene copolymer, polyurethane elastomer, epoxy 41tJIL epoxidized phenol formaldehyde resin, acrylic resin, and the like. Further, the above resins may be used alone or as a mixture as the case may be. Since the core material is atomized in a crushed or dispersed state, it must have a sufficiently low melt viscosity.In general, the softening temperature is 5 to 200°C. The softening temperature is preferably about 30 to 150°C.

In addition, the oil contains magnetic powder, coloring pigments, dyes, water-based solvents, charge control agents, curing agents, and fluids! II modifier and stabilizer cape additives are added as necessary.

All known dyes and pigments can be used as coloring agents, such as carbon black, 1Jil, nigercin, benzidine yellow, and quinacridone.

Examples include Rhodamine B and Fujl Russianine Blue. The amount of pigment added is adjusted as appropriate depending on the pigment O's used and the degree of coloring. Heat W of core material when used as toner
I - 80% by weight or less, preferably 70% by weight or less, particularly preferably 30 to aol, based on the resin to improve fluidity
ijl: Add X.

In addition, as magnetic powder, any substance that is magnetized when placed in a magnetic field can be used, and generally powders of ferromagnetic metals such as iron, cobalt, and nickel, or magnetite,
There are compounds such as hematite and ferrite. The content of this magnetic powder is 10 to 80% by weight based on the weight of the core material, preferably 30 to 60 weight iX.

Other additives used in the present invention include various metal complexes,
Charge control agents such as nigrosine, iron black, and graphite; lubricants such as polytetrafluoroethylene;
Examples include plasticizers typified by dicyclohexyl phthalate.

At this time, if too much additive is added, the viscosity becomes too high, making it difficult to atomize by spraying, and causing problems such as the pumping pressure being too high. The above window material is used by heating p1 to which a solvent is added if necessary.

As the iron material used in the present invention, any material that is liquid at room temperature and soluble or dispersible in water and organic and inorganic solvents can be used. Furthermore, a part of the iron material used in the present invention can be added to the core material.

As iron materials, for example, styrene monomer, seven μlsunarene, methacrylic acid, methacrylate:・,
Acrylic acid, acrylate.

Maleic acid, borico: tyrene ori:/-(-, Bo!J ester oligomer, polyamide oligomer, polyurethane oligomer, polybutadiene, 9-vinyl vinegar, 5-enal to 2-vinylpyridine, ethyl amino enal methacrylic acid, diethylamino ether acrylic Acids, 2-methyl-5-vinylpyridine, vinylpyrrolidone, etc. The above compounds may be used alone or as a copolymer, or in a mixture state solubilized or dispersed in water and an organic or inorganic solvent. 3. The medium used in the present invention to be supplied onto the surface to be deposited includes dimethylformamide, dimenalacetamide, N-methylpyrrolidone cicada amides, methyl ethyl ketone, methyl isobutyl ketone, methyl globil ketone, diethyl ketone, Ketones such as cyclohexanone, ethers such as dioxane, tetrahydrofuran, ethyl ether, ethylene glycol jet ether, esters such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, ethylene glycol monoethyl acetate, glycol diacetate, etc. kind, n
-butyl alcohol, especially alcohols such as -7'' alcohol, isobutyl alcohol, cyclohexanol, benzyl alcohol, methylene methylene, β.

These include chlorine-substituted hydrocarbons such as β'-dichlorodiethyl ether, and o=tro compounds such as nitromethane and nitroepone. These solvents are added in an amount of 1 to 100% by weight, preferably 5 to 50 weight 11N, based on the resin.
1. The present invention optionally includes a crosslinking agent, an N-interval initiator, 1 a coloring agent, and a charge control agent. , a curing agent, a dynamic regulator, a stabilizer, etc. may be added.

The amount of the shell material used in the present invention can be selected within a wide range in order to exhibit good electrophotographic properties. Generally, the iron material is added so that the thickness of the shell material forming film is 4t-Tk to 10 times, preferably twice as much as the core material particle size. This makes it possible to form a toner that has both good visibility and good fixing properties.

In the present invention, the discharge machine for forming the core particle '4I' includes a two-fluid nozzle with a high voltage shaft stop device 1' [ΦLB], a pressure nozzle, and a rotary disk fatigue bell. Preferably, a two-fluid nozzle or bell which is opened in instantaneous contact so that the injection directions are parallel or intersecting in order to atomize into droplet fusion core + 4 families, and a large number of atomizers (I-micro-machined rotating disk type bell) are used. The window material to be discharged at this time is sufficiently kneaded in advance in a commonly used homomixer, disperser, roll mill, sand mill, ball mill, centrifil, or sasmeyer mill.

The pressure at which the window material is transferred to the atomizing head consisting of a nozzle or bell can be arbitrarily adjusted to obtain the desired particle size.

Unless the nozzle is used for A-u, the pumping pressure is generally 1
~100? The window material is transferred at a hot air pressure of preferably t5 to 50 to/- and a degree of trough of t5 to 50. When using a rotating Dinuk type bell, generally 1~2009/
min, preferably at a transfer rate of 20 to 100 f/min. When using a rotating disk type bell, the number of revolutions of the bell depends on the window material used, but is generally 1,000 to 100,000 rpm, preferably 50 rpm.
Used at 00 to 5 oooorpm. The pump that transfers the fluid is a centrifugal type that can maintain a constant continuous flow with little pulsation.

Reciprocating single-rotation pumps such as Polito pumps, turbo pumps, propeller pumps, gear pumps, screw pumps, partition pumps, magnet pumps, laboratory pumps, diaphragm pumps, bellows pumps, and Panton pumps are preferred.

In the present invention, the high voltage applied to the nozzle or bell is generally 2 to 200 LV, preferably 40 to 90 KV. The applied voltage mentioned above also depends on the material used, but if the applied voltage is lower than the above range, the particles will not be sufficiently atomized, and if the applied voltage is higher than the above range, the atomization effect will be saturated and the effect of increasing the voltage will appear. Not done.

In the present invention, microcapsules are produced by flying the window material, which has been atomized using an atomizing head, into a medium containing shell material on a grounded surface to be coated. The grounded surface and the atomizing head to which voltage is applied must be kept at a distance that will not cause dielectric breakdown.

In the present invention, the distance between the atomizing head to which voltage is applied and the surface to be coated usually depends on the applied voltage, but if the applied voltage is 80 KVo, the distance is 50 to 500 rm1, preferably 100 to 200 rrrn. be done. The microcapsule toner suspension obtained in the present invention can be further polymerized by transferring it to a carrier reactor for MX reaction, or by continuously transferring it to a tube system equipped with a heating jacket. . Usually, polymerization is 50 to 150
The reaction may be carried out for 5 to 10 hours at a temperature range of 60 to 100°C.

Examples are shown below. The number of copies is a heavy cover.

[Example 1 100 parts of copolyethylene resin 20 parts of ethylene-vinyl acetate copolymer 80 parts of magnemate A gear pump is used to supply the bell portion at a discharge rate of 50 f/min. The bell is a G bell (manufactured by Landsburg) with finely machined grooves.
Using 30.000 rpm z applied voltage -80KV
It was atomized.

On the other hand, 20 parts of styrene-acrylic acid ethyl ester copolymer 3 parts of diethylaminoether methacrylate A solution prepared by dissolving the above mixture in DMF was applied to the surface to be coated at 3 t/min.
, at a rate of . The obtained microcapsule toner was collected and further heated and polymerized in a reactor at 80° C. for 5 hours. When the particle size distribution was measured using a Coulter counter, the volume average particle size was 9.9Ifn, 6.35μ~2
It was found that toner having a particle size between 0.2 Ifn comprised 90% by weight of the total particles. Furthermore, when 0.3 weight X of hydrophobic colloidal silica was added and the image was developed using an improved NP-120 (Canon copier), clear copies with good fixing properties were obtained.

[Example 2] Polyethylene (☆) resin 100 parts Ethylene-vinyl acetate copolymer 20 parts Magnetite
80 parts The above mixture was cross-mixed at 120°C for 2 hours using a homomixer 1'', and the melt was mixed at 50 f/w using a metering gear pump equipped with a heating island and a heating tube.
It is supplied to the bell section at a discharge speed of 1.5 in. The bell uses a 90 bell (manufactured by Landsburg) with finely machined grooves, 30.00
0 rprn was atomized at an applied voltage of -80 KV.

On the other hand, 20 parts of styrene-acrylic acid ethyl ester copolymer 3 parts of methyl methacrylate
It is fed at a rate of n. The obtained microcapsule toner was cooled and further heated and polymerized in a reactor at 80°C for 5 hours.

When the particle size distribution was measured using a Colemaker Lanter, it was found that the toner having a volume average particle diameter of 9.7 .mu.m and a particle diameter between 6.35 .mu.m and 20.2 .mu.m contained 9.2% of the total particles by polymerization. Furthermore, 0.3% by weight of hydrophobic colloidal silica was added, and the resulting image was developed using an improved NP-120 (Canon Co., Ltd. copying machine). Clear copies with good fixing properties were obtained.

[Example 3] Polyethylene resin 100 parts Ethylene-vinyl acetate copolymer 20 parts Magnetite
80 parts of the above mixture was mixed with 120 parts using a homomixer.
U. The melt that has been cross-wired for 2 hours is heated at 50 f/mi using a metering gear pump equipped with a heating pot and heating tube.
It is supplied to the bell section at a discharge speed of n. The bell has a micro-machined groove and uses a 9G bell (manufactured by Landspurg) go, ooor.
pm, and atomization was performed at an applied voltage of -80ff.

On the other hand, styrene-acrylic acid ethyl ester copolymer 2(l
Methyl methacrylate 3 parts The above mixture was applied to the surface to be coated with MFKPM at 3t/mi.
It is fed at a rate of n. The nine microcapsule toners obtained were collected and further heated and polymerized in a reactor at 80° C. for 5 hours. When the particle size distribution was measured using Coulter counter sound, the volume average particle diameter was 9μrn, 6.85μ~20.
It has been found that the toner having a particle size between 2 and 30% contains 92% of the total particles. Historically hydrophobic colloidal silica 0
.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a device applicable to the present invention. DESCRIPTION OF SYMBOLS 1... Rotating bell, 2... Mounted object, 3... Drained pulp, 4... Collection tank, 5... Minute sensitive tank, 6... Gear pump, 7... Air turbine 7-tar, 8...
Dispersion medium supply pump, 9... Supply hose, 10... Dispersion medium tank.

Claims (1)

[Claims] ``A microcapsule toner produced by atomizing a component serving as a core material into a liquid containing a shell material when a voltage is applied, and further polymerizing the resulting dispersion.