JPS58216258A - Microcapsule toner - Google Patents

Abstract

PURPOSE:To obtain a microcapsule toner having uniform grain sizes, by producing said toner by an electricaly emulsifying method. CONSTITUTION:Components such as polyester resin, alkyd resin, carnauba wax or the like that form a core material are discharged and atomized from the end of a nozzle or disc into liquid contg. polystyrene, acrylic resin or the like that forms a shell material under application of a high voltage. Since the core material is atomized in a molten or dispersed state, the material is required to have a substantially low melt viscosity, and in general, the core material having about 30-150 deg.C softening temp. is preferable. 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 said toner 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 relates to a microencapsulated electrophotographic developer (so-called toner) having a uniform particle size and manufactured using an electroemulsification method.

In general, electrophotography is a method of forming and developing an entire image on the surface of a photoconductive material using an electrostatic copying device. 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 to deposit toner on the electrostatic image. By this, the latent image is developed. At this time, the toner normally adheres selectively only to the portion where the electric charge t is held, and a toner gIt corresponding to the static image is generated there. Next, this powder 1#
It is transferred onto a support such as lVc paper and permanently affixed to the surface of the support by applying heat or pressure. In the above case, it is necessary to heat the toner to fkAJ&' where the toner melts and flows, or to pressurize the toner with a pressure that deforms its shape.

Conventional electrophotographic production methods include solid resins, liquid resins, and semi-solid resins, and if necessary, magnetic powder, colorants, hardeners, and other additives. A method of manufacturing by melt-mixing and then mechanically pulverizing is used. However, in such a method, it is extremely difficult to control the particle size and particle size distribution (1-1tJII) of the toner, and the shape of the particles inevitably becomes angular. Physical properties such as stability deteriorate, and handling becomes inconvenient due to the use of dry pulverization.For example, if dry mechanical pulverization is used in the process of manufacturing toner, it has the following disadvantages. (1) ) Regarding toner production, it is necessary to crush the toner at an economical speed, so if soft materials are used, they will adhere to the machine and become difficult to crush.For this reason, hard materials are generally not used. However, toner manufactured using easily pulverized materials encounters unexpected problems.For example, as the pulverization progresses further in the developing machine, extremely ridged toner particles stain the inside of the machine, image fogging, and smearing occur. The following phenomenon occurs. (
2) Due to mechanical crushing, the buried colorant is spilled onto the surface, resulting in partial non-uniformity of triboelectric charging characteristics, that is, asymmetrical charge, which causes poor contrast and resolution.

Furthermore, some colorants may cause moisture absorption. (3) Since an amorphous toner is produced by the pulverization, it is impossible to point the toner to a point where the electrostatic density on the photoelectric surface is at its maximum, which causes chewing and fogging. (
4) Soft materials with good pressure fixability are difficult to crush because they fuse to the walls of the machine. In order to improve the above-mentioned drawbacks of dry mechanical pulverization, it is necessary to use a medium such as water to promote heat diffusion of the Joule heat generated in the pulverization process.

Particularly effective as a pressure fixing toner is a toner that satisfies both fixability and developability at the same time, that is, a microencapsulated toner. On the other hand, a soft, concrete abrasive material is generally used as a core material for microcapsule toner. There are two known methods for producing microcapsule particles of uniform particle size using soft core particles that are difficult to dry mechanically crush, the first being Jubei.

1) Wet pulverization method U) Spray drying method The wet pulverization method is a method in which the core particles are formed in advance using a wet thread, and the whole shell is formed at the same time, without any pulling, and the entire shell is formed into microcapsules. 0, that is, a dispersion process or emulsification for preliminarily dividing the core material into relatively small particles VC, 1:41 or more [
The first step consists of an encapsulation step a<referred to as the second step) in which Fj k is applied on top of the encapsulation step (referred to as the second step). It is necessary to form uniform fine particles by adding the agent and using high-speed stirring and ultra-11 wave pulverization. This is a step of depositing and fixing the mosquito material onto the surface 5. The interface method, phase separation method, and thermal gradient precipitation method can be used to deposit and fix the core particles onto the surface of the core particles. It is possible to strengthen chemically or physically. However, in this method, a large amount of emulsifier that acts on the atomization of the first step is subsequently carried out, and in the second step, it inevitably remains on the surface of the core material, greatly reducing the adhesive strength of the shell material. At the same time, a large number of single particles generated only from the shell material are generated,
When the particle size is uniform as desired, the microencapsulated toner, which exhibits good separability, is separated, and furthermore, the remaining emulsifier causes a moisture absorption phenomenon, which adversely affects the electrophotographic characteristics. In addition to the above-mentioned drawbacks, in order to produce microcapsule toner by a wet pulverization method, a problem arises in that particle size broadening inevitably occurs due to mechanical deterioration. - The method of producing microcapsule particles using the force spray dry mass method is to knead the base material and the shell material in advance in the atmosphere or disperse them in a medium. In this method, the shell material is discharged from a nozzle and fixed onto the surface of the core particle. However, the microcapsule particles obtained by this method generally have a wide particle size distribution and tend to become coarse.

The purpose of the present invention is to solve the above-mentioned drawbacks and to provide a
iI! ! The present invention provides a microcapsule toner that is left behind.

The microcapsule toner produced by the present invention applies a high voltage to the base material that is ejected from the nozzle or the end of the disk and is atomized, resulting in a decrease in the surface tension of the material, which results in effective electrophotographic properties. Core material particles having a particle diameter of a certain lOμ Sakai degree and a narrow particle size distribution are produced. As a result, the microencapsulated toner particles produced by adhering the shell material to the core material can also be obtained as microencapsulated toner particles with uniform particle diameter. Since the resulting microencapsulated toner has a narrow electrophotographic particle size distribution, it can be used as an electrophotographic toner without being classified or with only a slight classification operation.
This is what we provide.

It is a refreshing object of the present invention to provide a microcapsule toner that contains little or no emulsifier that inhibits the formation of shell materials.

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

Its characteristic feature is that it is a microcapsule toner in which the core component is atomized into the liquid containing the shell material when a voltage is applied. However, any printing material that can be dispensed with a nozzle or bell into the media containing mosquito material can be used. In general, qkJ materials that exhibit a liquid or suspended dispersion state upon discharge are used, such as polyester resins; polyester-based urethane polymers; polyester-based alkyd resins:
Trimellitic acid ester, rosin ester, modified rosin ester of borocabrolactone.

Various citron-based polyester fall fats represented by the reaction product of isopropylidene diphenoxypropanol and acyhinic acid, the reaction product of isopropylidene phenoxypropanol and sebacic acid, etc.; polyethylene wax, carnauba wax, castor wax, rice wax, Schlack wax, Zazol wax, Amide wax.

Montan wax, microcrystalline wax, ceresin wax, paraffin wax.

Waxes represented by osikerite: behenine amide, sudearic acid azedo, balmitic acid amide, lauric acid amide, erucic acid amide, 'braidic acid amide, oleic acid amide, elaidic acid amide, methylene bisbehenic acid amide, methylene Bisstearic acid amide, methine bisoleic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisoleic acid amide, octamethylene biserucic acid amide, monoalkylolamide, dihydric linoleic acid and diamine or polyamine Polyamide resins typified by polyamides produced from polyamides, reaction products of dicarboxylic acids and linear diamines; polyvinyl acetate; ethylene-vinyl acetate copolymers; polyisobutylene; polystyrene; dodecyl acrylate-styrene copolymers ; polyurethane elastomer; epoxy resin; epoxidized phenol formaldehyde resin; acrylic resin. Further, the above resins may be used alone or as a mixture depending on the case. These core materials must have a sufficiently low melt viscosity to be atomized in a molten or dispersed state, and generally have a softening temperature of about 5 to 200°C, particularly preferably a softening temperature of 30 to 1
A temperature of about 50°C is preferable.

Furthermore, additives such as magnetic powder, color pigment, dye, water-miscible solvent, electric shock control agent, hardening agent, flow control agent, and stabilizer shade are added to the binder resin as required. All known dyes and pigments can be used as layer colorants, such as carbon black and iron black.

Nigrosine, benzidine yellow, quinacridone, 1
- Daminro, phthalocyanine bluenato garu 0 1114 according to the type of pigment used and the degree of skin color. When used as a toner, 30 to 60% by weight of sogkA is added to 411 fat, preferably 70% by weight or less, particularly Ilft, to improve the thermal acid melt fluidity of the self-core.

As the 1c4IIi powder, any substance that is magnetized when placed in a stoneware factory can be used, generally powders of strong metals such as iron, cobalt, and nickel, or magnetite, hematite, and ferrite. There are compounds such as

The fineness of this image-forming powder is used in the range of 10 to 80 degrees per core, and 30 to 60 times for electrolytic corrosion. Other additives used in the present invention include various loincloth metal complexes, nigrosine, iron black, graphite, etc., additives, lubricants such as polytetrafluoroethylene, Examples include plasticizers typified by dicyclohexyl phthalate. At this time, if the additives are removed by force, the viscosity decreases, making it difficult to atomize by jetting, and the pumping pressure becomes too high, causing an undesirable sound. The above-mentioned base material is used by adding a solvent or heating it if necessary.

As the mosquito 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. Further, a portion of the shell material used in the present invention can be added to the core material.

Examples of mosquito materials include polystyrene, bo+)mo/chlorstyrene, and modified methacrylic resin.

Methacrylate 4M resin, polyacrylic acid, acrylate resin, polyethylene oligomer, polyester oligomer, polyamide oligomer.

Polyurethane oligomer, polybutadiene, vinegar wt
Vinyl, ho! J (5-ethyl-2-vinylpyridine), diethylaminoethyl methacrylic #salt, diethylainoethyl acrylic acid resin, poly(2-methyl-5
-vinylpyridine).

Examples include poly(vinylpyrrolidone). The above-mentioned compounds are applied to the surface to be coated, either alone or as a copolymer, optionally in a mixture, in water and an organic or inorganic agent.

Examples of the medium used in the present invention include amides such as dimeterformamide, dimenalacetamide, and N-methylpyrrolidone, ketones such as methyl ethyl ketone, methyl isobunal ketone, methyl propyl ketone, diethyl ketone, and cyclohexanone, and dioxane. Ethers such as tetrahydrofuran, ethyl ether, ethylene glycol diethyl ether, methyl formate, ethyl formate, methyl acetate, ethyl acetate, ethylene glycol monoethyl acetate, esters of glycol diacetate e, n
-Alcohols such as butyl alcohol, 5ee-phtyl alcohol, isobutyl alcohol, cyclohexanol, benzylalkonyl, chlorine ta hydrocarbons such as methylene chloride, β, β'-dichlorodiether ether, unitromethane, nitroethane, etc. These include nitro compounds.

The weight of these solvents is 1 to 1001 nm, preferably 5 to 50 weight, relative to the resin!忤 is added.

Crosslinking agent (9) Polymerization initiator, optionally used in the present invention.

A coloring agent, a charge control agent, a curing agent, a flow 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 fully exhibit good electrophotographic properties.

In general, the thickness of the shell material is determined by the particle size of the core material.
The shell material is added in an amount of 10 times, preferably 500 = 50 times. This makes it possible to produce a toner that has both good developability and good fixability.

In the present invention, examples of the discharge machine for producing core particles include a two-fluid nozzle equipped with a high voltage generator, a pressurized nozzle, and a rotating disk type bell.

Preferably, in order to atomize the m-melted core brush, a two-fluid nozzle or a rotating disk-shaped bell with a number of finely machined grooves in the atomizing head of the bell, which are opened adjacently so that the injection directions are parallel or intersect, is used. It will be done. The base material to be discharged at this time is thoroughly kneaded in advance using a commonly used homomixer, Tesperser, roll mill, sand mill, ball mill, Sentry mill, or Sassmeyer mill.

The pressure for transferring the base material to the atomization head consisting of a nozzle or bell is arbitrarily adjusted in order to obtain the desired particle size r.

Unless a two-fluid nozzle is used, the pumping pressure is generally 1
~1001c41/crn-Kokake 2~10 k4
The base material is transferred at 17 cs'' and a hot air pressure of 5 to 50 g/l, x'' phase change. Further, when a rotary disk bell is used, the number of rotations of the bell depends on the core abrasive used, but is generally used at 1000 to 1000 rpm, preferably 5000 to 50000 rpm. When using a 1-turn disk bell, generally 1 to 2 (J
O#/min Preferably, the pump supplied at a transfer rate of 20 to 1[10g/min is a long-l7 type, double-rotation type, two-rotation type pump that has little pulsation and can maintain a constant continuous flow. , Bolito Bong, Turbo Bong,
Propeller pump, gear pump, screw pump.

Divider pump, magnet pump, lab pump.

Diaphragm pumps, bellows pumps, bunton bongs, etc. are preferred. In the present invention, the high voltage applied to the nozzle or bell is generally 2 to 200 KV, preferably 40 to 90 KV. The voltage indicated by mark 7JI1 above depends on the material used, but if the applied voltage is lower than the above range, the particles will not be atomized sufficiently, 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 be reduced. Not expressed.

In the present invention, as a method for microcapsulating, the core material, which has been atomized in advance with an atomizing head, is grounded and fc4
It is produced by flying the tL coating onto a medium containing husks.

The grounded 4M coating surface and the atomizing head to which voltage is applied must be kept at a distance that does not normally cause dielectric breakdown.

In the present invention, the distance between the atomizing head to which a voltage is applied and the object to be coated can normally be influenced by the applied voltage, but when the applied voltage is 80 to 500 V, the distance is preferably 100 to 500. They are installed 209gm apart.

In the present invention, the microcapsule toner M can be obtained by cooling the 1 M suspension of microcapsule toner M or directly filtering it.

Examples are shown below. Parts are parts by weight 0 [Example 1
．． ] Polyethylene resin 100 parts Ethylene-vinyl acetate Corporal fMIF 20ff Magnetite 80 parts The above mixture was kneaded at 120° for 0.2 hours using a homomixer.
The 0 bell supplied to the bell section at a discharge speed of 097 m1n uses a G bell (manufactured by Landsburg) with micro-machined grooves.
Atomization was carried out at 0,000 rpm and an applied voltage of -80V. On the other hand, styrene-acrylic acid ethyl ester copolymer 20
Part diethylaminoethyl methacrylate resin 3
The above mixture is supplied to the coated surface at a rate of 3/min.The obtained microcapsule toner is collected, filtered and dried, and the microcapsule toner is dried. When the particle size distribution was measured using a Coulter counter, the volume average particle size was 10.9 μff.
It was found that the toner having a particle size between 6.35 μm and 20.2 μm contained 92% of the total particles by weight. 0.3% by weight of hydrophobic colloidal silica was added to the NP-
120 (Canon Co., Ltd.) Improved copying machine was used for visual imaging, and clear copies with good fixing properties were obtained.

[Example 2. ] Polyethylene resin 100 parts ethylene-vinyl acetate combination 20 parts magnetite
80 parts of the above mixture was kneaded for 120'0.2 hours using a homomixer.
The Q-bell supplied to the bell section at a discharge speed of 0 f/min is an O-bell (manufactured by Landsberg) with micro-machined grooves.
Atomization was carried out at 30,000 rpm and an applied voltage of -80V. On the other hand, steel V-acrylic acid ethyl ester copolymer 2
0 parts methyl methacrylate resin 3
A solution prepared by dissolving the s-top-pi mixture in DIVI 11'.31! It is fed at a speed of /min. The obtained microcapsule toner was collected, filtered and dried, and the particle size distribution was measured using a Coulter counter with the microcapsule toner, and the volume average particle diameter was 102 μf.
It was found that toners with particle sizes between fl, 6.35μ and 20.2 double weight contained 1% d9ii of the total particles.

Add 0.3% hydrophobic colloidal silica to 1M,
NP-120C-f Yanon copier) improved machine (rc-(
Despite my concerns, the fixing properties were good and clear copies were obtained with a 7'C.

[Example 3. 〕Polyethylene Minami AViooo Part Ethylene-Shenyl Copolymer 20s Magnetite
The bath melt obtained by kneading 80 parts of the upper Hj mixture at 120'0.2 hours 1ii1 using a homomixer was sent to Bell City at a discharge rate of 509/min using a metering gear pump equipped with a heating pot and a heating tube. supply The bell is a G bell (manufactured by Landsburg) with finely machined grooves.
Atomization was carried out at 30,000 rpm and an applied ridge pressure of -80 (V).
3 parts diethylaminoethyl methacrylate 3 parts diethylaminoethyl methacrylate 3 parts of the above mixture dissolved in DMFK;
Feed at a rate of 7/min. The obtained microcapsule toner was collected, filtered and dried, and the particle size distribution was measured using a Coulter counter.
．． 88 trays 11 of toner particles with all particles between 2 μm
It was found that 0.0.3% of hydrophobic colloidal silica was further added with an electric current to NP-120 (Key?/
Copying machine manufactured by Y) After being developed using an improved machine, it had good fixing properties and produced clear copies.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a device capable of applying the present invention V (two applications). 1...Rotating bell, 2...@Pickles, 3...° drain valve, 4... Fruit thinning ＊＋ 5...distributed reality, 6...
Gear pump, 7... Air turbine motor, 8...
・Dispersion medium supply pump, 9... Vessel supply pump, 10...
Dispersion medium tank. Applicant Canon Co., Ltd.

Claims (1)

[Claims] Microcapsule toner obtained by atomizing into a liquid containing the core component T-shell material when voltage is applied.