JPH01116560A - Encapsulated toner - Google Patents

Abstract

PURPOSE:To surely fix a toner to a base material with a lower pressure by constituting a core of a colored aq. soln. or a colored aq. dispersion. CONSTITUTION:The title toner is constituted of a core and a shell enclosing said core, wherein said core is constituted of a colored aq. soln. or a colored aq. dispersion. Examples of the colorant for the colored soln. or dispersion are several dyes such as azo dyes, reactive dyes, etc., carbon black, or magnetic powder such as iron/aluminum alloy powder, etc. The colored liquid contg. the colorant is aq. soln. or aq. dispersion. By this constitution, an encapsulated toner is broken at a low pressure and surely fixed to a base material.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a capsule toner for developing an electrostatic latent image formed on a photoreceptor in an image forming apparatus such as a copying machine.

<Prior Art> Conventionally, when forming a copy image using an image forming apparatus such as a copying machine, the Carlson method has been widely adopted. The above-mentioned Carlson method includes a charging process in which a photoreceptor is uniformly charged by corona discharge, and an exposure process in which an original image is exposed to the charged photoreceptor to form an electrostatic latent image corresponding to the original image.
A development process in which the electrostatic latent image formed on the photoconductor is developed with toner to form a toner image on the photoconductor, a transfer process in which the toner image is transferred to a base material such as paper, and the toner transferred to the base material. The basic process is a fixing process to fix the image. Also,
As a fixing method in the above fixing step, a heat fixing method is widely used in which toner containing a thermoplastic resin is heated and melted using a heating device such as a heat roll, and this heat fixing method has excellent fixing properties. This has the advantage that a duplicate image can be obtained. However, in the heat fixing method, since it is necessary to heat the heating device to a predetermined temperature, the image forming device cannot be started immediately, and the energy efficiency when heating and melting the toner is not sufficient. However, since a heating device is required, the structure of the image forming apparatus becomes complicated and the size of the image forming apparatus increases.

On the other hand, a pressure fixing method is also known as a fixing method that can simplify the configuration of an image forming apparatus and quickly form an image without requiring waiting time. This pressure fixing method uses a pressure fixing toner whose main component is a material that is easily plastically deformed, such as polyethylene wax, but the fixing properties are not sufficient, and if the copied image is handled roughly, the image area may be attached to the substrate. There is a problem of peeling off from the surface.

In view of the above points, a capsule toner in which the inner core is composed of a hydrous copolymer of acrylamide and 2-methylpropanesulfonic acid has been proposed in order to improve the fixing performance in the pressure fixing method (Japanese Patent Application Laid-Open No. (See Publication No. 103359).

<Problems to be Solved by the Invention> According to the above capsule toner, since the inner core is composed of a water-containing copolymer,
Although it has the advantage of being able to fix with a small pressure, since the inner core substance is composed of a copolymer in a water-containing state, the pressure required during fixing to destroy the capsule is still large, and it is difficult to fix the toner with a small pressure. There is a problem that it is difficult to fix it on the material.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a capsule toner that can reliably fix toner on a substrate with even lower pressure.

Means and operation for solving the above problems> In order to achieve the above object, the capsule toner of the present invention is a toner comprising a core and a shell containing the core,
The core is characterized in that it is a colored aqueous solution or a colored aqueous dispersion (hereinafter referred to as colored liquid).

According to the capsule toner having the above structure, since the core is a liquid colored liquid, applying a small pressure to the shell can destroy the shell and fix the colored liquid as the encapsulated substance on the base material.

The present invention will be explained in detail below.

The capsule toner of the present invention is composed of a core made of a colored liquid and a shell enclosing the core.

Examples of the coloring agent in the coloring liquid include azo dyes, acridine dyes, xanthine dyes, benzoquinone dyes, naphthoquinone dyes, anthraquinone dyes, azine dyes, oxazine dyes, dioxazine dyes, and thiazine dyes. , azomethine dyes, indigo and thioindigo dyes, phthalocyanine dyes, oxidation dyes such as aniline black, polymethine dyes, sulfur dyes, triphenylmethane dyes, diphenylmethane dyes, thiazine dyes, thiazole dyes, xanthine dyes , various dyes such as reactive dyes; carbon black, lamp black, chrome yellow, Hansa yellow, benzidine yellow, suren yellow G, quinoline yellow, permanent orange GTR, pyrazolone orange, palkan orange, watch young red, permanent red, brilliant Various pigments such as Carmine 3B, Brilliant Carmine 6B, Pyrazolone Red, Lysol Red, Rhodamine B Lake, Lake Red C1 Aniline Blue, Ultramarine Blue, Phthalocyanine Green, Ru, Phthalocyanine Green, Titanium Oxide; Oxidized or Reduced Iron, Silicon Steel , ferrite, nickel, cobalt, etc., and alloys of these with manganese, zinc, aluminum, etc., such as iron/nickel alloy, iron/cobalt alloy, iron/cobalt alloy, etc.
Examples include magnetic powder such as aluminum alloy.

The above coloring agents may be used in one type or in a mixture of two or more types depending on the desired image color. Note that the magnetic powder is mainly used when the capsule toner is a magnetic toner.

The colored liquid containing the above coloring agent exists in the form of an aqueous solution or an aqueous dispersion. More specifically, when the colorant is a dye, it is present in the form of an aqueous solution of the dye, and when it is a pigment and magnetic powder, polyvinyl alcohol is used to increase the stability and fixing properties of the colorant. , carboxymethyl cellulose, hydroxyethyl cellulose, shellac,
It exists in the form of a colored aqueous dispersion dispersed in water together with water-soluble binder resins such as acrylic polymers, polyvinylpyrrolidone, polyacrylamide, and styrene-maleic acid copolymers. Note that if the substrate on which the image is formed is a permeable substrate such as paper, it may be an aqueous solution or colored aqueous dispersion of the dye, and if the substrate is a non-permeable substrate , in order to improve the adhesion to the substrate, the colored liquid is
It is preferable that the water-soluble binder resin is contained.

Note that the colored aqueous dispersion may contain a dye.

Among the above-mentioned colored liquids, an aqueous solution of a dye is preferred because it not only forms a homogeneous and stable core but also allows fixing with even lower pressure.

The content of the colorant in the coloring liquid is not particularly limited, and an appropriate amount is used depending on the hiding rate of the colorant.

The core made of the above-mentioned colored liquid is enclosed within a shell made of various organic polymers.

The shell may be a single film made of an organic polymer, or may be a plurality of films made of a combination of different types of organic polymers. In the case of a capsule toner in which the shell is composed of a plurality of films, by adjusting the characteristics of the outermost film, the properties required for the capsule toner, such as triboelectric charging properties, degree of hydrophobicity, etc., can be adjusted. Mechanical strength etc. can be further controlled. In addition, when the shell is composed of a single film, it is preferably composed of an interfacial polycondensation film. Further, when it is composed of a plurality of films, it is preferably composed of a multilayer film consisting of a combination of the interfacial polymerization condensation film and the film made of the organic polymer, especially a radical polymerization film. More specifically, the shell consisting of a plurality of films includes an interfacial polycondensation film made of polyester, polyamide, polyurethane, polycarbonate, etc., and an organic polymer film, particularly a radical polymerization film, covering the interfacial polycondensation film. It is preferable that the

Examples of the organic polymer film include styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide, epoxy resin, polyarylate,
Examples include organic polymer films made of various polymers such as polysulfone, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, and phenol resin. It can be formed by attaching and covering the interfacial polycondensation film with the various organic polymers described above.

In addition, examples of radical polymerization films include radical polymerization films of styrene polymers, styrene-acrylonitrile copolymers, acrylic polymers, styrene-acrylic copolymers, and polyvinyl acetate. The polymer film can be formed by radically polymerizing a radically polymerizable monomer on the interfacial polycondensation film.

Note that the radical polymerization film and the organic polymer film may be formed in a single layer or in multiple layers using the same or different materials.

The volume ratio of the core to the shell and the thickness of the shell of the capsule toner are not particularly limited, and can be appropriately set depending on the desired pressure fixability.

Further, in order to control the frictional charge polarity, charge amount, etc. of the capsule toner, the shell preferably contains a charge control agent.

Examples of the charge control agent include oil-soluble dyes such as nigrosine dye, oil black, and spirone black, fatty acids such as naphthenic acid, salicylic acid, octylic acid, and stearic acid, and resin acids such as rosin, aluminum, manganese, and iron. , cobalt, lead, zinc, cerium, calcium,
Examples include metal soaps that are metal salts such as nickel, metal-containing azo dyes, pyrimidine compounds, and alkyl salicylic acid metal chelates, and they may contain one or more types. The content of the charge control agent is not particularly limited, and may be contained in an appropriate amount in the shell, but 0.1
Preferably, the content is 5% by weight. In particular, in order to increase the amount of charge on the toner due to frictional charging, the charge control agent is
Preferably, it is contained in the surface layer of the shell. Capsule toners in which the shell contains a charge control agent and capsule toners in which the surface layer of the shell contains a charge control agent contain a charge control agent as a raw material component forming an interfacial polycondensation film or as the radically polymerizable seven polymers. If necessary, a solution of a charge control agent containing an organic polymer may be used to immerse the capsule toner in the solution of the charge control agent. It can be obtained by spraying a solution of the control agent onto a capsule toner and drying it.

Note that, in order to further improve the characteristics of the toner, the shell may be subjected to various treatments depending on desired characteristics.

More specifically, when the shell has hydrophobicity,
Although not necessary, to enhance triboelectric properties,
Preferably, the shell is hydrophobically treated. The above-mentioned hydrophobic treatment can be carried out by treating or coating the outer layer of the shell with a hydrophobic treatment agent, a hydrophobic organic polymer, or the like. As the hydrophobizing agent, polyisocyanate compounds such as tolylene diisocyanate,
Epoxy compounds such as ethylene glycol diglycidyl ether and bisphenol type epoxy resins, amino resins such as benzoguanamine resin and melamine resin, and surface treatment agents such as titanium such as isopropyl triisostearoyl titanate and tetraisopropyl bis(dioctyl phosphite) titanate. Coupling agent, trimethoxyvinylsilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, trimethoxy-3-mercaptopropylsilane, 2-(3,4
-Epoxycyclohexyl)ethyltrimethoxysilane, 2- <3.4-epoxycyclohexyl)ethyltriethoxysilane, 3- (2,3-epoxypropoxy)propyltrimethoxysilane, 3- (2,3-epoxypropoxy)propyl Examples include silane coupling agents such as triethoxysilane. The hydrophobization treatment using the above-mentioned treatment agent is carried out by immersing the capsule toner in a solution of the above-mentioned hydrophobization treatment agent or spraying the solution of the hydrophobization treatment agent onto the capsule toner, and then heating the toner to remove the organic polymers constituting the shell. This can be done by reacting with a hydrophilic substance such as a hydrophilic organic polymer present on the surface of the shell.

Examples of hydrophobic organics and polymers include silicone oils or silicone resins, styrene polymers, acrylic polymers, polyesters, polycarbonates, polyurethanes, ketone resins, natural waxes such as carnauba wax, and synthetic waxes such as polyethylene. is exemplified. To coat the capsule toner with these hydrophobic organic polymers, 1. After immersing the capsule toner in a solution of the hydrophobic organic polymer or spraying the solution of the hydrophobic organic polymer onto the capsule toner, the solvent is removed. This can be done by

The above-mentioned hydrophobizing agent and hydrophobic organic polymer may be used alone or in combination with each other.

The amount of treatment with the hydrophobizing agent or hydrophobic organic polymer can be set as appropriate, but is usually 0.001 to 5% by weight, preferably 0.01 to 1% by weight, based on the shell. be.

In addition, the shell of the capsule toner may contain an anti-offset agent, for example, to prevent offset during fixing.
Preferably, the shell contains 0.5 to 15% by weight of low molecular weight polypropylene, low molecular weight polyethylene, various waxes such as paraffin wax, fatty acid amide, silicone oil, etc. per shell.

In addition, if it is necessary to increase the conductivity of the shell, a conductive substance such as carbon black may be added together with the hydrophobizing agent or hydrophobic organic polymer by the same method as above or by means such as fusion. It may be attached to the shell by.

The shape of the capsule toner having the above structure may be oval or the like, but when used as a toner,
A spherical shape is preferred in order to improve fluidity and triboelectric charging efficiency. Further, the capsule toner may have a cluster shape in which at least one capsule is enclosed within a shell.

The average particle size of the capsule toner is preferably about 5 to 25 mm. If the average particle size of the capsule toner is less than 5 .mu.m, image fogging increases, and if it exceeds 25 .mu.m, the image becomes rough.

The capsule toner having the above structure can be produced by various methods, for example, conventional methods such as interfacial polycondensation method and radical polymerization method.

When producing a capsule toner by the interfacial polycondensation method, a colored liquid in which a water-soluble reactive substance, which is one raw material of the interfacial polycondensation film constituting the shell, and the colorant are dissolved or dispersed in water, and the above-mentioned interface An organic solvent solution is prepared by dissolving an oil-soluble reactive substance, which is another raw material for the polycondensation membrane, in a water-insoluble organic solvent together with a charge control agent if necessary.

Then, after preparing a W10 type emulsion by dispersing a water-insoluble organic solvent in the colored liquid containing the water-soluble reactive substance, adding the organic solvent solution containing the oil-soluble reactive substance while stirring, An interfacial polycondensation reaction is carried out at the W10 interface to form capsules in which a core made of a colored liquid is encapsulated in a shell made of the interfacial polycondensation membrane, and the capsules are separated by a method such as filtration and dried. be able to. At that time, it is preferable to use a dispersion stabilizer to ensure the stability of the w10 emulsion, and it is preferable to use a pH stabilizer to maintain the pH of the reaction system.

More specifically, for example, to produce a capsule toner having a shell made of 6,6-nylon, polyvinyl alcohol, hydroxyethyl cellulose, albumin, anionic surfactant, cationic surfactant, nonionic surfactant are used. Dispersion stabilizers such as, pH of sodium hydroxide, sodium carbonate, etc. that function as dehydrochlorination agents.
a stabilizer, and the water-soluble reactive substance 1,6-
A colored liquid containing hexamethylene diamine and a coloring agent is prepared.

Next, a water-insoluble organic solvent that may contain the surfactant and the like as necessary, such as benzene, n-hexane, cyclohexane, methylene chloride, carbon tetrachloride, etc., is added to the colored liquid while stirring. Then, a W10 type emulsion having a predetermined particle size is prepared.

Then, an organic solvent solution in which adipoyl chloride, which is the oil-soluble reactive substance, is dissolved in a water-insoluble organic solvent is added to the emulsion system with stirring, and after interfacial polycondensation is performed for a predetermined period of time, it is filtered and the organic solvent By removing such substances, a powdered capsule toner can be obtained.

In the above-mentioned interfacial polycondensation method, the above-mentioned diamine such as 1,6-hexamethylene diamine is used as the water-soluble reactive substance which is the starting material, and as the oil-soluble reactive substance,
A shell made of 6,1o-nylon or polyamide can be formed by using a dibasic acid chloride such as sebacic acid chloride or phthalic acid chloride.

In addition, diethylene triamine, 1,6-hexamethylene diamine, etc. are used as water-soluble reactive substances, and tetramethylene dichlorocarbonate, tolylene diisocyanate, 4゜4'-diphenylmethane diisocyanate, etc. are used as oil-soluble reactive substances. This makes it possible to form a shell made of polyurethane. Furthermore, resorcinol, 4.4-
- A shell made of polyester can be formed by using isopropylidene diphenol or the like and terephthalic acid chloride or the like as an oil-soluble reactive substance. In addition, it does not contain water-soluble reactive substances,
Using a colored liquid containing a catalyst and sodium hydroxide,
By using bisphenol chloroformate, which is a polycarbonate precursor, as the oil-soluble reactive substance, a shell made of polycarbonate can be formed.

The particle size of the emulsion can be controlled by adjusting the amount of the dispersion stabilizer, the stirring speed, the stirring time, the ratio of the colored liquid to the organic solvent, and the like.

Further, a capsule toner whose shell is composed of a plurality of films can be manufactured as follows using the capsule toner obtained as described above. That is, a predetermined amount of a radically polymerizable monomer is added together with a polymerization initiator to a dispersion in which the above capsule toner is dispersed in a W10 emulsion state while stirring, and the mixture is supplied to the oil phase of the above W10 emulsion. A powdered capsule toner can be obtained by adding a predetermined amount of an aqueous solution containing a dispersion stabilizer to form a [W10]/W type emulsion, performing a radical addition polymerization reaction, and then removing water and the like. can.

Examples of the radically polymerizable monomer include acrylic esters such as butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, stearyl acrylate, cyclohexyl acrylate, and phenyl acrylate, and methacrylic esters corresponding to these. , styrene, α-methylstyrene, p-methoxystyrene, p
Examples include styrenic monomers such as -chlorostyrene, vinyl acetate, unsaturated polyesters, alkyl esters of carboxylic acids having unsaturated double bonds such as dibutyl maleate, vinylpyrrolidone, epoxy methacrylate, and urethane methacrylate.

The above radically polymerizable monomers may be used alone or in combination of two or more. Further, in order to produce a capsule toner in which a charge control agent is contained in the shell, a radically polymerizable monomer containing a charge control agent may be used as described above.

When an interfacial polycondensation film is coated with a radical polymerization film to form a shell having a plurality of films as described above, triboelectric charging characteristics can be controlled by changing the type of radically polymerizable monomer.

At this time, by also changing the type of charge control agent, the charging characteristics of the capsule toner can be further controlled.

Incidentally, the powder and wood-like capsule toner obtained as described above are dispersed in an aqueous phase, and a radically polymerizable monomer is added in the same manner as above, and the radically polymerizable monomer is coated with a radically polymerized film. Multiple layers of polymeric films can be formed.

Further, in the manufacturing process as described above, the dispersion stabilizer and the like may be adsorbed onto the surface of the capsule toner, which may adversely affect the triboelectric charging characteristics. In such a case, it is preferable to wash the obtained capsule toner with water or the like to remove the dispersion stabilizer, or to treat or coat it with the hydrophobic treatment material or hydrophobic organic polymer.

Since the capsule toner obtained as described above has a core composed of a colored liquid, a large pressure is not required to destroy the shell, and the shell can be destroyed with a pressure of usually 15 ki/cm or less. This allows the colored liquid to be reliably fixed on the substrate.

Therefore, the capsule toner of the present invention is suitable as a developer for developing an electrostatic latent image formed on a photoreceptor in an image forming apparatus such as a copying machine, a laser beam printer, or a facsimile. Note that the capsule toner of the present invention has -
Used as component toner or two-component toner.

<Examples> The present invention will be described in more detail below based on Examples.

Example 1 Aqueous solution 3 containing 0.5% by weight of polyvinyl alcohol
．． Ovl, 1,6-hexamethylene diamine 0.14
g (0.4 mol), sodium carbonate 0.19 g (0
, 45 mol) and black azo dye (C, 1, Ac1d
Black 52) colored aqueous solution 31! was added and dissolved. A benzene-cyclohexane (1:4) mixed solvent 301 containing 1.5% by weight of a surfactant (manufactured by ICI, trade name Span 85) was added to the obtained colored liquid! and stirred at 7500 rpm for 10 minutes at a stirring speed of 3000 rpm.
The W10 type emulsion was prepared by stirring for 10 minutes at a stirring speed of pm.

Next, while stirring the emulsion, 30% of adipoyl chloride was added to 30% of an organic solvent having the same composition as above.
．． 15'M! and charge control agent (manufactured by Orient Chemical Co., Ltd.,
A capsule toner with an average particle size of approximately ICIm is obtained by adding an organic solvent solution in which Bontron S5-34) 3111 (trade name) is dissolved and performing an interfacial polycondensation reaction for 3 minutes, followed by filtering and removing the organic solvent. Created.

Example 2 W10 type emulsion 10 was prepared in the same manner as in Example 1 above.
After preparing 0 '11, the emulsion was mixed with propylene glycol: phthalic anhydride: maleic anhydride - 5:3.
:70% by weight of unsaturated polyester synthesized at a molar ratio of 2
0.15% by weight of sodium metaborate was added to a system consisting of 10g of a radically polymerizable supernatant consisting of 30% by weight of styrene, 1g of the charge control agent of Example 1 above, and 0.3g of lauroyl peroxide, and the mixture was heated with a homogenizer. Stir, W1
A type 0 emulsion was prepared.

Next, the above emulsion was mixed with polyvinyl alcohol 0
．． 5% by weight aqueous solution 20011! to prepare a [W10]/W type emulsion, react at a temperature of 7°C for 5 hours, filter, wash with water, and dry to obtain capsules of ICII with an average particle size. A toner was produced.

When pressure fixing properties were investigated using the capsule toners of Examples 1 and 2 obtained as described above, it was found that the linear pressure was 15k.
It was found that the capsule was destroyed at 100 g/cm. Also,
The above capsule toner 5% by weight, ferrite carrier 95
When a developer consisting of It turned out that it was possible.

<Effects of the Invention> As described above, according to the capsule toner of the present invention, since the core is composed of a colored liquid, the toner can be destroyed with small pressure and can be reliably fixed to the base material. It has the effect of

Claims (1)

[Claims] 1. A capsule toner comprising a core and a shell enclosing the core, wherein the core is a colored aqueous solution or a colored aqueous dispersion. 2. The capsule toner according to claim 1, wherein the core is an aqueous solution of a dye. 3. The capsule toner according to claim 1, wherein the shell is formed of a plurality of films including an interfacial polycondensation film and a radical polymerization film. 4. The capsule toner according to claim 1, wherein the shell contains a charge control agent.