JPS6135457A - Developing method - Google Patents

Abstract

PURPOSE:To obtain a developing characteristic which decreases the mutual deterioration by development by using a two-component developer consisting of the toner particles and carrier particles in which the concn. of the component change continuously from the surface layer part toward the central part of the toner particles to develop the image on an image carrying body. CONSTITUTION:The system consisting of, for example, a polymerizable monomer into which a dye, pigment, cationic polymer or anionic polymer and other additives according to need are incorporated is dispersed into a dispersion medium to form the toner. The anionic dispersant and cationic dispersant prevent the coalescence of the particles with each other and stabilize the particles by binding ionically on the particle surface of the polymer. The concn. of the components from the surface layer part to the central part of the toner particles forms a kind of pseudo capsule where the polar polymer exists much in the surface layer part and decreases gradually toward the central part. The polar polymer having such a suitable degree of polymn. as to prevent the mutual deterioration by the collision and contact of the toner and carrier particles by the repeating phenomena as a result of continuous use is used for the part corresponding to the surface layer part, by which the developing characteristic is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing method using carrier particles in an image forming apparatus.

[Prior Art] Conventionally, as an electrophotographic method, U.S. Patent No. 297; 891
Specification, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 4
A number of methods are known, as described in Japanese Patent No. 3-24748, etc., but generally a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then The latent image is developed using toner, and the toner image is transferred to a transfer material such as paper if necessary, and then fixed by heat, pressure, solvent vapor, or the like to obtain a copy.

Various methods and devices have been developed for the above-mentioned final step, which is the step of fixing the toner image on a sheet such as paper. The most common method at present is the compression heating method using a heated roller.

In an image forming apparatus using carrier particles, a cascade method, a microtoning method, a two-component magnetic brush method, and the like are known as developing methods for developing a latent image.

For example, in a magnetic brush development method in which a developer consisting of a mixture of toner and carrier is adsorbed and conveyed by a developer support means and developed by rubbing it against an image holding surface, the device can be made more compact;
The area covered by the developing area relative to the image holding surface is small;
It has been widely adopted in recent years because it has less knee 2D effect and can provide uniform images. As a means for supporting and transporting the developer, there is a method that rotates a non-magnetic cylinder (sleeve) having a permanent magnet fixed therein. In this case, in the development area where the sleeve and the image carrier are close to each other, there are two types: a forward development method in which the developer rotates in the same direction as the image carrier, and a reverse development method in which the developer rotates in the opposite direction. Ru.

In recent years, there has been a demand for higher quality copied images, and it has become necessary to uniformly and evenly reproduce not only line images such as characters but also large area solid images such as photographs.

Particularly in recent years, toners that easily melt at relatively low temperatures have been desired, and the currently common method is a fixing method using a heated roller.

The pressure heating method using a heated roller performs fixing by passing the toner image surface of the sheet to be fixed under pressure while contacting the surface of a heated roller whose surface is made of a material that has releasability for toner. . In this method, the surface of the heat roller and the toner image on the sheet to be fixed come into contact under pressure, so the thermal efficiency when fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. However, in the above method, because the heated roller surface and the toner image contact each other under pressure in a molten state, a portion of the toner image is exposed to the fixing roller surface. The toner adheres and transfers to the next sheet to be fixed, causing a so-called offset phenomenon, which can stain the sheet to be fixed.It is important to prevent the toner from adhering to the surface of the heat fixing roller. It is considered one of the essential conditions for the arrival method.

Various types of toners used in this manner are known. These are constructed to be compatible with the above-mentioned developing method and fixing method. Although the toner is constructed in such a manner as to satisfy the development characteristics and fixing characteristics, it is generally difficult to balance the development characteristics and fixing characteristics. In order for the toner to fix, the wood must have adhesion and cohesion, and for development, each toner must move independently, which are fundamentally contradictory requirements. This is because there is. These conditions are becoming more and more demanding, especially when high-performance toners, toners that develop and fix at high speed, and toners that fix with little energy (for example, very little pressure) are required. becomes. In other words, the more it is attempted to make a toner with better fixing properties, the more severe the development characteristics become.

Conventionally, toners used for electrostatic image phenomena are generally made by melt-mixing colorants and other additives in thermoplastic resin.
After uniform dispersion, the solidified product is finely pulverized and classified to produce colored fine particles of a desired particle size. Although this manufacturing method can produce fairly good toners, it does have certain limitations.

That is, the toner that is removed using the grinding process must be brittle to make the material somewhat susceptible to grinding. However, if the toner is too brittle, it will be too finely pulverized, and in order to obtain a toner with an appropriate particle size distribution, it will be necessary to cut the toner into fine particles, which will increase the cost. Furthermore, in the developing device of a copying machine, the toner is sometimes further pulverized. Furthermore, when a material with a low melting point is used to improve heat fixability, a fusion phenomenon occurs in a crushing device or a classification device, and continuous production may not be possible.

Other requirements for toners include having triboelectric properties suitable for development, forming good images, no change in performance when left unused, no solidification (blocking, etc.), and adequate heat fixing properties. Examples include not contaminating the photoreceptor surface, carrier particle surface, etc.

Particularly in fixing, attempts have been made to add a large amount of polyolefin or use polyolefin with a low melting point to prevent offset, but these attempts have resulted in fusion in the crusher or classifier, or low melting point polyolefin on the toner surface. Exposure of the polyolefin caused problems such as blocking lag, contamination of the surface of carrier particles, and poor fluidity, which significantly reduced developability.

Furthermore, the toner produced by the conventional pulverization method is Toner-1fi.
Since the shapes of each grain are different and irregular, it is thought that the triboelectric properties of each grain are different, and the fluidity is also poor, which is thought to cause variations in developability. .

Spherical toners have been proposed to overcome the various drawbacks of these pulverized toners. For example, the spray method has been known for a long time. However, this method involves melting the resin or dissolving it in a solvent, spraying it out in a mist form from a nozzle, and then cooling or drying it to obtain toner. Therefore, it is difficult to obtain a toner that satisfies the above-mentioned drawback of fixing offset property by t(t L L, S.

Amemata, polyolefin, etc. are incompatible with woody resin and tend to precipitate unevenly on the surface of the sphere during cooling or solvent evaporation. l B < 03 a
On the other hand, in order to overcome the drawbacks of the pulverization method, a method for producing toner using a suspension polymerization method has been proposed.

That is, since it does not involve any pulverization process, it does not need to be brittle, and because it is spherical, it has excellent fluidity, and therefore triboelectric charging is uniform.

However, even with this method, it cannot be said that the toner is fully satisfactory. This is because the entire polymer is almost homogeneous, so if you lower the molecular weight and Tg to improve heat fixing properties, blocking properties will worsen, and this will contaminate the carrier particle surface and photoreceptor surface, making it difficult to develop. This also reflects the image quality and deteriorates the image quality. On the other hand, if polymerization or cross-linking is performed excessively in order to improve blocking properties, this will lead to a vicious cycle in which heat fixing properties deteriorate. It is difficult to satisfy the conflicting properties of developability.

Furthermore, a method for producing toner using a microcapsule method has been proposed for the same purpose.

However, until now, the practical ones are:
It has not been announced yet. One reason for this is that materials that are suitable as toner materials are not necessarily suitable as microcapsule materials;
In particular, it is difficult to impart toner development suitability, particularly charge controllability, to the material constituting the wall.

Currently, a common encapsulation method involves dispersing a solid core material in a solution of a material that forms a wall and envelops the core material, and then removing the solvent using heat or other means to form a wall and enveloping the core material. Some materials precipitate a substance around a core material. This method has the advantage of being able to use materials with clear origins, such as materials with excellent fixing properties and materials with excellent developability, while preserving the characteristics of the materials, but since it uses a solvent, The combinations are limited. In addition, even within these limited combinations, the core material material is not completely insoluble, and it is difficult to completely prevent the elution of low molecular weight components, which are intentionally made to exist in order to improve fixing properties. However, this eluted component may prevent the wall material from adhering to the surface of the core material, or the core material may be mixed into the wall material, which may adversely affect developability and durability. Therefore, there is a problem that sufficient functional separation cannot be achieved.

Furthermore, even with microcapsule toners that have overcome the above-mentioned difficulties, the impact caused by the impact during the developing operation
There are also problems such as peeling of wall materials, and in order to put microcapsule toner into practical use, there are issues such as the completeness of the coating and the durability of the coating.
At present, there are still many issues that need to be resolved.

In this way, many conventional two-component developers produce toner and carrier particles that collide with toner particles and carrier particles due to repeated development through continuous use and contact between them and the photosensitive surface.
Mutual deterioration of carrier particles and photoreceptor results in poor triboelectric charging and flow properties, changes in the density of the resulting image, or increases in background density, reducing the quality of copies. Furthermore, if an attempt is made to increase the density of a copied image by increasing the amount of toner adhering to the surface of a photoreceptor having a latent image, the background density usually increases, resulting in a so-called fog phenomenon.

[Problems to be Solved by the Invention] The present invention has been made to provide a developing method using toner particles and carrier particles that overcome these problems and have good development characteristics with little mutual deterioration during development. .

[Means and effects for solving the problems] The present invention uses a two-component developer consisting of toner particles and carrier particles in which the concentration of the components changes continuously from the surface layer to the center of the toner particles. The present invention also provides a developing method for developing an image on an image carrier.

The present invention will be explained in detail below.

The toner used in the developing method of the present invention includes, for example, a polymerizable monomer containing a dye, a pigment, a cationic polymer or anionic polymer as a polar polymer, or other additives as necessary. It can be obtained by dispersing the system in a dispersion medium containing a dispersant, preferably by suspending it in a highly polar dispersion medium (for example, water) in which a dispersant having an opposite charge to the polar polymer is dispersed, and then polymerizing it. Here, the anionic dispersant and the cationic dispersant primarily bond with the cationic polymer or anionic polymer contained in the polymerizable monomer on the surface of the polymer particles, resulting in the coalescence of the particles. prevents and stabilizes particles. That is, since the cationic polymer and anionic polymer gather on the surface of the suspended particles, they form a kind of shell-like form, and the resulting particles become pseudo-capsules.

That is, the toner particles obtained by the present invention become a kind of pseudo-capsule in which the concentration of components from the surface layer to the center is such that a large amount of polar polymer exists in the surface layer and gradually decreases toward the center.

That is, regardless of the initial polymerization of the polymerizable substance,
As the cationic polymer or anionic polymer for the surface layer portion, a resin having a desired degree of polymerization can be used. Therefore, the interior is polymerized to a relatively low molecular weight material with excellent fixing properties, and the surface layer is a cationic or anionic polymer that has a relatively high molecular weight and has good blocking resistance. Resins with excellent properties and wear resistance can be used.

This has the following effects.

In other words, the composition can be considered by relatively separating the surface layer portion and the center portion. Even if the central part has a relatively low molecular weight and low softening composition that has good fixing properties but is prone to mutual deterioration due to collision and contact with carrier particles due to repeated development due to continuous use, the surface part can be used continuously. Development characteristics can be maintained by using a polar polymer with a suitable degree of polymerization that prevents mutual deterioration due to collision and contact between toner and carrier particles during repeated development.

Furthermore, since it is spherical, it has excellent fluidity and therefore has uniform triboelectric charging properties.

The above characteristics are as follows: 1. It is preferable that the toner particles obtained by the present invention have a weight average molecular weight of 10,000 or more and a glass transition point of 40° C. or more.

As the carrier particles, for example, iron powder, glass beads, nickel powder, ferrite powder, or those obtained by treating these with a resin or other modifying material, etc. are used.

A method of analyzing the concentration of components in the depth direction from the surface of toner particles according to the present invention will be explained.

Generally speaking, the method for performing analysis from the surface to the depth direction is as follows:
X-ray microanalysis (EPMA), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIN!)
1lf), Rutherford backscattering (RBS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (
Laser Raman microprobe (MOLE) etc. are used. However, when it comes to analyzing microparticles from the surface to the depth direction, there are only a limited number of methods that can be applied, and EPMA
, XPS, FT-IR, etc., but FT-
IR(7)PAS method (photoacoustic spectroscopy) or MIR method (multiple internal reflection method) is preferred. In the KIR method, the penetration depth is determined by the type of prism and the angle of incidence of the light, and it also changes depending on the wavelength, so it is difficult to determine the penetration depth. Therefore, in the present invention, the PAS method was used. P
In the AS method, an IR chart of a portion from the surface to a certain depth can be obtained by integrating several steps in the depth direction using a certain thickness as a unit in the depth direction from the particle surface. For example, by integrating 5 steps using 1'JLI11 as a unit, O (surface) ~IILm, O ~ 2gm
, O-3ILm, 0-4p, m, and 0-5Bm IR charts corresponding to the respective thickness portions can be obtained.

If each component exists uniformly in the toner particles, the IR chart at each stage will give the same peaks and peak ratios, but if they are localized, the peaks and peak ratios will change. In other words, by focusing on a certain characteristic absorption peak and calculating the differences at each stage, it is possible to obtain an IR chart corresponding to a certain thickness at a certain depth, and by comparing the peaks and peak ratios of each part, it is possible to determine the particle size. The concentration of components in the depth direction can be measured almost continuously.

The toner used in the developing method of the present invention is preferably close to spherical, and has a Wardell practical sphericity of 0.95 to 1.0.
Preferably it is 0. Here, Wardell's practical sphericity is a value expressed as the ratio of the diameter of a circle with an area equal to the projected area of the target particle to the diameter of the smallest circle circumscribing the projected image of the target particle, and is more specifically Specifically, it was measured by the following method. That is, an appropriate amount of toner is placed on a slide glass, and individual toner particles are brought into contact with each other.
Spread them out so they don't overlap. These toner particles are imaged on a CR7 screen using Luzex 450 (Japan Regulator Acid) at a microscope magnification of 500 times. Here, Luzex 450 can freely select any particle as long as it exists separately and measure its projected area, so the diameter of a circle having the same area can be calculated from this. On the other hand, this CR7 screen is photographed as it is, and the diameter of the smallest circle circumscribing the projected image of the particles is determined by drawing. Here, the above ratio was calculated for 100 randomly selected toner particles, and the average value was determined, which was defined as "Wardell's Practical Sphericity."

Among the polar polymers used in the present invention, cationic polymers are polymers that migrate to one electrode by electrophoresis, such as dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, Diethylaminoethyl methacrylate, dibutylaminoethyl methacrylate,
Vinylpyridine, N-n-butoxyacrylamide, 2
-Hydroxy-3-methacryloxypropyltrimethylammonium chloride%, g1$ A polymer obtained from nitrogen-containing monomers such as those obtained by quaternizing these nitrogens, or 1 selected from the above monomer group species or two
Examples include copolymers obtained by copolymerizing one or more monomers with a monomer copolymerizable with the monomers.

Monomers to be copolymerized with monomers such as dimethylaminoethyl methacrylate include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, and p-methylstyrene.
-Methoxystyrene, P-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, P-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p- 11
-hexylstyrene, p-n-octylstyrene, p-
n-nonylstyrene, p-n-decylstyrene, p-n
- styrene and its derivatives, such as dodecylstyrene;
Ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; Vinyl esters such as vinyl acetate, vinyl propionate, and vinyl benzoate Class; methyl methacrylate,
α-Methylene aliphatic monomers such as ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, etc. Carboxylic acid esters; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylic acid 2 - Acrylic esters such as chloroethyl and phenyl acrylate; 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; N-vinylpyrrole , N-vinyl compounds such as N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

Among the polar polymers used in the present invention, anionic polymers are polymers that migrate to the living electrode by electrophoresis, such as acrylonitrile, methacrylonitrile, α
- Monomers containing nitrile groups such as chloroacrylonitrile and vinylidene cyanide, vinyl chloride, vinylidene chloride,
Monomers containing halogens such as vinyl bromide, vinyl fluoride, chlorostyrene, 2-hydroxy-3-chloropropyl methacrylate, di-chlorostyrene, bromostyrene, acrylic acid, methacrylic acid, α-chloroacrylic acid, etc. Monomers containing carboxyl groups, unsaturated dibasic acids such as maleic s, fi water maleic acid, half ester maleic acid and their derivatives, nitro groups such as o-nitrostyrene, m-nitrostyrene, p-nitrostyrene, etc. monomer containing 2-acrylamido-2-methylpro/-, O
sulfonic acid, N-methylolacrylamide, sodium styrene sulfonate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, polypropylene glycol monomethacrylate, tetrahydrofurfuryl methacrylate, acid phosphooxyethyl methacrylate, etc. hydroxyl group,
A polymer obtained from a monomer consisting of an ethylene glycol group, a propylene glycol group, a sulfonic acid group, a salt thereof, a phosphoric acid group, or a glycidyl group, or one or more types selected from these monomer groups. Examples include copolymers obtained by copolymerizing a monomer with a monomer that is copolymerizable with the monomer.

Monomers to be copolymerized with monomers such as acrylonitrile include styrene, 0-methylstyrene, 0-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, .4
-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-ter
t-butylstyrene, p-n-hexylstyrene, p
-n-octylstyrene, p-n-nonylstyrene,
p-n-decylstyrene, p-n-dodecylstyrene,
Styrene and its derivatives such as: ethylenically unsaturated olefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate,
Vinyl esters such as vinyl propionate and vinyl benzoate: methyl methacrylate, ethyl methacrylate,
α-Methylene aliphatic monocarboxylic acid esters such as propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, and phenyl methacrylate. Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, acrylic Acrylic acid esters such as acid phenyl; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone,
Vinyl ketones such as methyl isopropenyl ketone; N
- N-vinyl compounds such as vinylpyrrole, N-vinylcarbazole, tovinylindole, and N-vinylpyrrolidone; vinylnaphthalenes: acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide;

In addition to the above polymers and copolymers, examples of anionic polymers include polyester resins, cyclized rubbers, phenolic resins,
Phenol-modified rosin ester resin, epoxy resin, silicone resin, etc. are used.

These polar polymers exhibit preferable properties when they have a number average molecular weight of 5,000 or more. If it is less than 5,000, especially less than 4,000, mutual deterioration due to collision and contact with the developer supporting member is likely to occur. These polar polymers are used in an amount of 1 to 30 parts by weight per 100 parts by weight of hexamer. 1
If it is less than 30 parts by weight, mutual deterioration tends to occur, and if it is more than 30 parts by weight, it becomes excessive.

Suitable dispersion media used in the present invention include, for example, any suitable stabilizer, such as polyvinyl alcohol,
Gelatin, methyl cellulose, methyl hydropropyl cellulose, ethyl cellulose, strium salt of carboxymethyl cellulose, polyacrylic acid and their salts, starch, gum alginate, zein, casein,
This stabilizer can be used by incorporating tricalcium phosphate, talc, barium sulfate, bentonite, aluminum hydroxide, ferric hydroxide, titanium hydroxide, thorium hydroxide, etc. into the aqueous phase and is stable in the continuous phase. The amount used is preferably within the range of about 0.1-10% by weight.

Anionic dispersants preferably used in the present invention are those that are negatively charged in water, such as water-soluble polymers such as partially saponified vinyl acetate homopolymers or copolymers, and Aerosil 11200 or 11300 (Japan Aero (manufactured by Seal), Nib Seal E-22OA (manufactured by Nippon Silica)
, Fine Seal T-32 (manufactured by Tokuyama Soda Co., Ltd.) and other finely powdered inorganic compounds such as Corroigluciliy.

Cationic dispersants are highly charged in water, and include, for example, aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, hydrophilic positively charged silica fine powder, and the like.

General surface treating agents can be used to obtain the hydrophilic positively chargeable silica fine powder used in the present invention. For example, there is one represented by the general formula Xm5iYn. or an alkoxy group, or a chloro atom. m:l or 2 or 3°Y is a hydrocarbon group having a primary to tertiary amino group. n
;3 or 2 or 1°H2N-1;H2NHGH2 in H2
CH2cH2si-(OCH3)2H2N-CONH-
OH2C) 120H, -5i- (QC, H, included) 1. N
-C)12G)1. C) I, 5i (DC) I, OH,)
.

H! NGH□CH2N HCH2CI 2CH2S r
(OCHj)s)1. NCH,0H2CI,5i(O
CH5)3H2? lCH, OH, MHC)! 2CH,W
HO■xc:H2cHzs r (OCHJ)3H,C
a0GOCI, OH,NHCH,0H2G■2Si(
OCH3)y■, C2000G! (20H, NHCH2
0H, HIGH2CH2CH, 5t(OCH,).

H, C20GOCH, 0H2NHCH, OH, NHCH
,Cl4NHCH,・Cl4NHCH,0H2CIyoS
i (OCH3)3NH,C6HpSi(OCH3)
j GaHsNHCH,OH,CI,5i(OCH,).

Alternatively, polyaminoalkyltrialkoxysilanes may be used, and these may be used alone or in a mixed system of two or more.

The silica fine powder may be treated by any general method, but for example, the silica fine powder may be stirred and a solution of the treating agent may be added little by little to the silica fine powder.

Another method is to vaporize and spray a treatment agent or a solution thereof onto fine silica powder in a gas phase.

Examples of polymerizable monomers to be suspension-polymerized in a dispersion medium in the presence of polar polymers, additives, dispersants, etc. include styrene, 0-
Methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene,
p-Chlorstyrene, 3,4-dichlorostyrene, p-
Ethylstyrene, 2,4-dimethylstyrene, p-n-
Butylstyrene, p-tert-butylstyrene, p
-n-hegylystyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene,
Styrene and its derivatives such as p-n-F decylstyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride,
Vinyl halides such as vinylidene chloride, vinyl bromide, and vinyl fluoride; Vinyl esters such as vinyl acetate, vinyl propionate, and vinyl benzoate: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate α-methylene aliphatic monocarboxylic acid esters such as isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, and phenyl methacrylate; methyl acrylate, ethyl acrylate, Acrylic acid esters such as n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; 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; N-vinyl pyrrol, N-vinyl carbazole, N-vinylindole, and N-vinyl Examples include indole and non-N-vinyl compounds; vinylnaphthalenes: acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

During polymerization, polymerization is carried out in the presence of the following crosslinking agent,
It may also be a crosslinked polymer.

Divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate methacrylate, 1
．． B Hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.2'bis(4-methacryloxyjethoxyphenyl)propane, 2.2'bis(4-acryloxyjetoxyphenyl) Common crosslinking agents such as (toxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentylglycol dimethacrylate, and allyl phthalate can be used as appropriate.

The amount of these crosslinking agents used is 0.00% based on the total amount of
01-15% by weight (more preferably 0.1-10% by weight)
) is better to use.

The polymerization initiator may be any suitable polymerization initiator, such as azobisisobutyronitrile (AIBN), benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorylbenzoyl peroxide. Polymerization can be carried out using oxide, lauroyl peroxide, etc. Generally, about 0.5 to 5% of initiator by weight is sufficient.

In addition, water-soluble polymers cause emulsion polymerization simultaneously in water and contaminate the resulting suspension polymer with small emulsion polymer particles, so water-soluble polymerization inhibitors, such as metal salts, are added to the water phase. It is also good to prevent emulsion polymerization of Furthermore, in order to reduce the viscosity of the medium and prevent coalescence of particles, glycerin, glycol, etc. may be added to the water. In addition, due to the decrease in water solubility of easily soluble monomers, Na0, KC, Na2
It is also possible to use salts such as SO'4.

In the suspension method, a monomer system in which a polymerization initiator, colorant, monomer, and additives are uniformly dissolved or dispersed is added to an aqueous phase, that is, a continuous phase containing a suspension stabilizer, in a conventional manner. Disperse using a stirrer, homomixer, homogenizer, etc.

Preferably, the monomer droplets have the desired toner particle size,
Generally 3011. Stirring speed, such that it has the following dimensions:
After adjusting the time, stirring and agitation may be carried out to such an extent that sedimentation of the particles is prevented, so that the state is substantially maintained by the action of the dispersion stabilizer. The polymerization temperature is set at 50°C or higher, generally from 70 to 90°C. After the reaction is completed, the produced toner particles are collected by a suitable method such as washing, filtration, decantation, centrifugation, etc., and dried. In addition, in order to adjust the degree of polymerization, a molecular weight regulator can also be used as appropriate.

When the toner is used as a color toner, a coloring agent may be added as necessary, and known pigments or dyes can be used as the coloring agent.

Examples of dyes include c, r, direct red 1, and c.
,1, Direct Red 4, C,1, Acid Red 1
．． C, 1, Basic Red i, c, ■, Modern Red 30, C, 1, Direct Blue 1, C1L Direct Blue 2, C, 1, Acid Blue 9, C, 1, Acid Blue 15, C, 1, H-C) )y blue 3, c, r.

Basic Blue 5, C, R, Mordand Blue, C
, 1, Direct Green 6, C, 1, Basic Clean 4, C, R, Basic Green 6, etc.

Pigments include yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow, permanent yellow NCG.
, Tartrazine Lake, Red Yellow Lead, Molybdenum Orange, Permanent Orange L/Nji GTR, Hirazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Eosin Lake, Brilliant Carmine 3B, Manganese Purple, Fast violet B, methyl violet lake, navy blue, cobalt blue, alkaline blue lake,
Victoria Blue Lake, Phthalocyanine Blue, First Sky Blue, Indan Stremburu-BG, Chrome Green, Chromium Oxide, Pigment Green B, Malachite Green Lake, Final Yellow Green G
, carbon black, etc.

In the toner, if necessary, a charge control agent, a coloring agent,
A fluidity modifier may be added, and the charge control agent and fluidity modifier may be mixed (externally added) with the toner particles. Examples of the charge control agent include metal-containing dyes and nigrosine, and conventionally known dyes and pigments can be used as the colorant, and examples of the fluidity modifier include colloidal silica and fatty acid metal salts. There is. In addition, for the purpose of increasing the volume, fillers such as calcium carbonate and fine powdered silica are added by 0.5 to 2
It can also be blended into the toner in a range of 0 wt%. Further, a fluidity improver such as fine Teflon powder may be added to prevent toner particles from coagulating with each other and improve fluidity.

[Example] Next, the present invention will be explained with reference to Examples.

Example 1 Styrene 170gn-butyl methacrylate) 30g styrene-dimethylaminoethyl methacrylate copolymer (1,000 mr ratio +1:1, Mn = 20,000)
10 g of 20 g β-type copper phthalocyanine flue (Dainichiseika) was heated to 70° C. to dissolve and disperse. This was heated to about 70°C in a container equipped with a high-shear mixer such as TK Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and then heated to about 70°C.
It was easy to understand. Thereafter, 6 g of azobis-(2,4-dimethylvaleronitrile) was dissolved.

Separately, 4 Aeroseal 112oo in 1000m fL of water.
g was dispersed, heated to 55°C, and the above monomer system was added to the TK homomixer while stirring, and the mixture was heated to about 80°C at 8000 rpm.
Stir for 1 minute. Thereafter, this mixed system was stirred using a paddle blade to complete the polymerization. Thereafter, the dispersant was removed with sodium hydroxide, followed by filtration, washing with water, and drying to obtain a toner.

Regarding the obtained toner, Kore-8 (I) was applied to FT-IR.
sX type)-PAS method was used to perform IR analysis from the surface to the center, and the following results were obtained.

Filling a measuring cell with the toner having an average particle size of 1 OJLlB,
After replacing the inside of the sample chamber of the PAS with He, IR was measured by the PAS method in 5 steps, that is, from the surface to a depth of 5 #Lm, increasing by 17111 from the surface to the center. Since this toner uses styrene-dimethylaminoethyl methacrylate copolymer as the polar polymer, we focused on a series of peaks from 2730 to 2825 caused by dimethylaminoethyl in the molecule, and analyzed the portion from the surface to 51L11. When the peak area generated by 100 is taken as 100, the peak area at each shallower step is as shown in the following table.

l O~IP description 32%2
0-2 53%3
0-3 68%4
0-4 85%5
0 to 5 100% From this, the content of dimethylaminoethyl groups at intervals of 1ILff1 from the surface is determined as follows.

0-1ILm 32% 1-2 21% 2-316% 3-416% 4-515% Also, absorption by dimethylaminoethyl groups in the IR chart of reflected light of the toner and the IR chart of dimethylaminoethyl methacrylate monomer As a result of peak comparison, the presence of at least 40% dimethylaminoethyl groups on the surface of the toner was confirmed.

This shows that many dimethylaminoethyl groups exist on the surface and gradually decrease toward the center.

That is, it was found that a large amount of the styrene-methylamine ethyl methacrylate copolymer in the raw material existed on the surface and gradually decreased toward the center.

Konotonawo Iron Powder * -? IJ 7- (EFV25
0/400) Nitoner content) Mixed at 10 wt%. As a result of reversal development of this developer using a copying machine NP-5500, good images could be obtained, and stable and good images could be obtained even after continuous printing of 50,000 sheets. Furthermore, the fixing properties were also good.

Comparative Example 1 The toner obtained in Example was mixed with a hot roll, pulverized, and classified to obtain a toner having a similar number average diameter. The obtained toner having an average particle size of 1O11.11 was analyzed in the same manner as in Example 1, and the content ratio of dimethylaminoethyl in each depth portion was determined as shown in the following table.

0 to IJJ, 1121% 1 to 2 20% 2 to 3 19% 3 to 4 18% 4 to 5 22% This shows that the dimethylaminoethyl group is almost uniformly present from the surface to the center. Ta.

When image printing was carried out in the same manner as in Example 1, the image quality and density were significantly inferior in continuous image printing of 10,000 sheets.

Example 2 Styrene lftogn-
Butyl methacrylate 40g Styrene-acrylonitrile copolymer (monomer ratio 85:15.Mn = 20.000)
10g pieces phthalocyanine green 1
0g was heated to 70°C to dissolve and disperse. This is T
The mixture was mixed for about 5 minutes while heating to about 70° C. in a container equipped with a high shear mixing device such as a K homo mixer (manufactured by Tokushu Kika Kogyo). Thereafter, 6 g of azobisisobutyronitrile was dissolved.

Separately, Aerosil Cloud 2004 was treated with 1000 tal of water and 10% of γ-aminopropylethoxysilane treatment agent.
g was dispersed and heated to 65° C., and the above-mentioned seven-mer system was added to the mixture under stirring using a TK homomixer, and the mixture was stirred at 8000 rpm for about 80 minutes. Thereafter, this mixed system was stirred with paddle blade stirring to complete one polymerization. Thereafter, the dispersant was removed with sodium hydroxide, followed by filtration, washing with water, and drying to obtain a toner.

The obtained toner was analyzed in the same manner as in Example 1,
2230c+e-' due to the nitrile group of the styrene-acrylonitrile copolymer used as a polar polymer
Focusing on the peak of , and assuming that the peak area generated by the portion from the surface to 5JLll is 100, the peak area at each shallower step is as shown in the following table.

To 1O-IP 42% 2 0-2 80%3
0-3 74%4
0-4 87%5
0 to 5 100% From this, the content of nitrile groups at intervals of 11 Lm from the surface is calculated as shown in the following table.

Nitrile group content ratio 0-1 river m 42% 1-218% 2-3 14% 3-4 13% 4-513% Also, from the reflected light IR of the toner, the surface of the toner was determined in the same manner as in Example 1. The presence of at least 45% monotolyl groups was confirmed.

As a result, it was found that nitrile groups were present in large quantities on the surface and gradually decreased toward the center.

Transfer this toner to an iron powder carrier (EF'fF250/40
0) Mixed with nitner content of 10wt$. As a result of developing this developer using a copying machine MP-5500, a good image could be obtained, and stable and good images were obtained even after continuous image printing of 50,000 sheets. Furthermore, the fixing properties were also good.

Comparative Example 2 The toner obtained in Example 2 was mixed with a hot roll, pulverized,
The toners were classified to obtain toners having similar number average diameters. The obtained toner having an average particle size of 10p was analyzed in the same manner as in Example 1, and the content ratio of nitrile groups at each depth was determined as shown in the following table.

0-IIL intestine 19% 1-2 21% 2-321% 3-418% 4-5 20% This revealed that the nitrile groups were present almost uniformly from the surface to the center.

When image printing was carried out in the same manner as in Example 2, the image quality and density were significantly inferior after 50,000 images were printed.

Example 3 A toner was obtained in the same manner as in Example 1 except that 40 g of the styrene-dimethylaminoethyl methacrylate copolymer was used. When I created the image in the same way, it turned out to be a good image.
The fixing properties were also good.

Example 4 The styrene-acrylonitrile copolymer of Example 2 was
A toner was obtained in the same manner except that g was used. When images were produced in the same manner, the images were good and the fixability was also good.

Example 5 A toner was obtained in the same manner as in Example 1 except that 1.5 g of divinylbenzene was added and the polymerization temperature was 60°C. When images were produced in the same manner, the images were good and there were no practical problems in fixing properties.

Example 6 Example 2 (diethylene glycol dimethacrylate) 1
．． A toner was obtained in the same manner except that 5 g was added and the polymerization temperature was 75°C. When images were produced in the same manner, the images were good, and there were no practical problems in fixing performance.

Example 7 A toner was obtained in the same manner as in Example 3 except that 1.5 g of divinylbenzene was added and the polymerization temperature was 80°C. When images were produced in the same manner, the images were good, and there were no practical problems in offset properties and fixing properties.

[Effects of the Invention] As described above, the developing method of the present invention uses toner particles in which the concentration of components changes continuously from the surface layer to the center of the toner particles. The components present in large quantities ensure fixing properties, and the components present in large quantities in the surface layer of the toner ensure blocking resistance, developability, and abrasion resistance, making it possible to form images of excellent image quality. Further, since the toner particles are combined with carrier particles, an even more excellent effect is exhibited by improving the image quality.

Claims (1)

[Claims] A developing method in which an image on an image carrier is developed using a two-component developer consisting of toner particles and carrier particles in which the concentration of the components changes continuously from the surface to the center of the toner particles.