JPH03293675A - Production of toner - Google Patents

Abstract

PURPOSE:To easily form a multilayer toner having a desired dielectric constant at low cost by attaching fine resin particles to the surface of each core particle and treating the attached fine resin particles with a solvent to form the outer shell of each core particle. CONSTITUTION:The outer shell of each core particle is formed by attaching the fine resin particles to the surface of each core particle, treating the resin particles with the solvent capable of dissolving them to form the outer shell of each core particle. When a highly dielectric material is contained in each core particle, the dielectric constant of the total toner rises, resulting in elevating the dielectric constant of the gap of a developing zone, thus permitting the toner near the toner to be used for developing trier in the binary development system, to stabilize a developing electric field, to reduce an edge effect, to maintain insulating property between each toner particle, accordingly, to stabilize triboelectrifiability, and therefore, the multilayer toner having a desired dielectric constant to be easily formed at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing an image forming toner using electrophotographic technology for use in printers, copying machines, facsimile machines, and the like. More specifically, the present invention relates to a method for producing a toner having a multilayer structure.

[Prior Art] In a developing device of an image forming apparatus using conventional electrophotographic toner, magnetic powder such as iron powder is used as a carrier.
A method using a two-component developer (for example, C, H) in which the toner is attached to the surface of the carrier by electrostatic force, and the movement of the carrier by the magnetic force is used to transport the toner and develop the electrostatic image carrier.

Young H, G, Greig: R, C, A.

15 (4), 471 1950) has been adopted.

In the two-component development method, the carrier acts as an electrode near the electrostatic image carrier, and the shape of the electric lines of force generated on the outer surface of the electrostatic image carrier can be modified to emphasize the so-called developing electric field, so that the entire image area can be Uniform and high-density development was possible.

However, this method has major disadvantages in that the life of the developing device is short due to deterioration of the carrier, and that the structure of the developing device and the control of the toner within the developing device are complicated in order to always maintain a constant mixing ratio of carrier and toner. For this reason, the two-component development method was not used in relatively advanced high-speed image forming apparatuses.

In order to solve these problems, a one-component development method (for example, U, S, P, 4121
A small, low-speed image forming apparatus using the image forming apparatus (No. 931) has been put into practical use. Toner may be conductive or insulating, but insulating toner is widely used from the viewpoint of transfer efficiency of toner onto recording paper.

Conventional insulating toners used in these development methods mainly consist of colored pigments such as carbon black, styrene-acrylic copolymers, thermoplastic resins such as polyester, or waxes uniformly dispersed in a single substance or a mixture. It was a powder made by adhering a charge control agent, a fluidization improver, etc. to the surface of the powder as an ingredient, if necessary. In particular, in the -component magnetic toner, fine ferromagnetic particles such as iron oxide are further uniformly dispersed in the main component.

The specific resistance of the toner in the aggregate state of powder is 1013 to 101
It had an insulating property of about 5 Ω■, and a general dielectric constant of about 3.

Methods for producing these toners include a kneading and pulverizing method, a suspension polymerization method, and a spray drying method. Currently, most of these are manufactured using the cross-wire crushing method. The kneading and pulverization method consists of the steps of premixing raw material powders, then melting and kneading, coarsely pulverizing, finely pulverizing, classifying, and external addition treatment. However, in recent years, there has been a demand for highly functional toners, and toners having various structures and manufacturing methods have been proposed. Among these, toner particles have a structure in which conductive particles are immobilized on the surface of the toner particles in a hot air flow, and insulating particles are further immobilized around the toner particles in a hot air flow to form a conductive layer and an insulating layer on the surface of the toner particles ( Japanese Patent Publication No. 63-257763). In addition, as a product having a multilayer structure, for example, microcapsule toner produced by a polymerization method (mainly aimed at low energy fixation) (
U.S. Patent No. 3080250, Japanese Patent Publication No. 59-31066
, Japanese Patent Publication No. 1-36934, etc.), and a toner having a charge control resin film layer on the outer periphery of the toner for the purpose of charge control using a dry high-speed impact method (Japanese Patent Application Laid-Open No. 63-62666). , a toner (Japanese Unexamined Patent Publication No. 1-105261) whose surface is treated with fine resin powder for the purpose of blocking resistance. Further, conventional forming methods include a spray drying method and a spray granulation method.

[Problems to be Solved by the Invention] However, in the method proposed in JP-A No. 63-257763, material deterioration occurs because heat treatment is performed. Using inorganic fine particles of carbon black and silica, 2
Since the process is repeated, there are problems such as the inability to obtain the desired resistance by mixing two types. Furthermore, in the conventional polymerization method, spray drying method, and spray granulation method, the conditions for forming the coating layer are strictly controlled, and the materials are limited. Furthermore, there are other problems such as the inability to freely control the thickness of the coating layer and the complicated manufacturing method. Furthermore, the dry high-speed impact method has the problem that if the viscosity of the core particles is lower than the viscosity of the fine particles, it is difficult to release the fine particles and form a uniform film.

Therefore, an object of the present invention is to solve the above-mentioned problems in a one-component development system that can realize miniaturization, simplification, and maintenance-free equipment without making the development gap extremely small and without having to strictly control it. Using resins with various dielectric constants in toner that can output high-quality images by correcting the electric lines of force generated from the electrostatic image carrier and emphasizing the developing electric field,
Furthermore, the thickness of the coating layer can be controlled arbitrarily to make it uniform and
An object of the present invention is to easily produce a multilayer structured toner having a desired dielectric constant at low cost.

[Means for Solving the Problems] The toner manufacturing method of the present invention comprises at least a binder resin and a colorant, has at least a two-layer structure, the outermost shell layer exhibits electrical insulation, and In a toner in which the effective dielectric constant of the inner core particles is higher than the dielectric constant of the outermost shell layer, a step of using at least resin fine particles to form the outermost shell layer and attaching the fine particles to the surface of the inner core particles; [Function] When the inner core particles contain a highly dielectric material, the toner The overall dielectric constant increases, and the dielectric constant of the gap within the development gap increases. It is believed that this allows the toner in the vicinity of the toner to be developed to serve as a carrier in the two-component development system, thereby making it possible to further stabilize the developing electric field and reduce edge effects. In addition, by maintaining the electrical insulation between the toner particles, the toner can be stably charged, and when the toner, which has been developed on the latent image carrier and has become a visible latent image, is electrostatically transferred onto the recording paper, the toner It is believed that an image of excellent quality is formed because a charge having a polarity opposite to that of the toner is injected into the toner, thereby preventing transfer defects from occurring.

In addition, as a manufacturing method, if the inner core particles are mixed with resin fine particles whose particle size is smaller than the inner core particles and treated by mechanochemical reaction, etc., the resin fine particles will have electrostatic force, chemical adsorption force, and physical adsorption force on the surface of the inner core particle. etc. to ensure uniform adhesion. Next, a solvent that dissolves the resin particles is brought into contact with the resin particles adhering to the surface of the inner core particle, whereby the resin is dissolved and a film made of the resin component is formed on the surface of the inner core particle.

The coating state at this time is controlled by controlling the type of solvent and the contact time, and the solvent in contact is quickly evaporated by heat and removed from the particles, thereby preventing agglomeration of the particles.

In this way, since a coating layer made of a resin component is formed on the surface of the inner core particle, the inner core particle is not affected by the solvent, and
Furthermore, for example, even if the inner core particles have a lower softening point and are softer than the fine particles, the coating layer can be reliably formed.

Hereinafter, the present invention will be explained in detail with reference to Examples.

[Example] FIG. 1 shows a flowchart of the toner manufacturing method of the present invention. Inner core particles 5 are formed by a cross-wire crushing method, a spray drying method, a polymerization method, etc. using raw materials consisting of a binder resin 1 and a coloring agent 2, etc.
1. Next, an external addition process 6 is carried out to attach the resin fine particles 3 to the inner core particles 5 to prepare the resin fine particles externally added inner core particles 7. 0. Next, a solvent is used to dissolve the resin fine particles in the externally added resin fine particles 7. 4 are brought into contact with each other to perform a coating treatment 8 to produce a resin outer shell coating toner 9.

The core particles used in the present invention are particles consisting only of resin, or particles containing at least one type of toner component. As toner components, a colorant, a charge control agent, a magnetic powder, a conductive agent, a fluidity improver, a release agent, a dispersant, etc. are selected as necessary. These inner core particles are prepared by a general kneading and pulverizing method, a spray drying method, or a polymerization method and have a particle size of 1 to 40 μm. The shape may be spherical or irregular.

As the fine particles for the coating, it is possible to use only resin fine particles or a mixed system containing resin fine particles and at least one of the above toner components. As a method for adhering the fine resin particles and the mixture system of the fine resin particles and toner components to the surface of the inner core particles, a normal mixer such as a ball mill or a V-type mixer can be used, but it is preferable to use a so-called high-speed fluid agitator. preferable. As the high-speed fluidized stirrer, a so-called Henschel mixer Mechano Fusion System (Wire Micron), Nara Hybridization System (Nara Kikai Seisakusho), Mechano Mill (Kaida Seiko), etc. are used. However, the device for fixing fine particles to the surface of the inner core particles is not limited to these. Next, methods for treating the solvent include spray drying, immersion, and the like, but any method may be used as long as the contact time can be controlled. Preferably, a powder coating device, such as Disper Coat (Nissin Seifun) or Coat Mizer (Freund Sangyo), is used.

The composition of the inner core particle is not particularly limited,
You can use common ones. For example, fixing resins include polystyrene and copolymers, such as hydrogenated styrene resins, styrene-isobutylene copolymers,
ABS resin, ASA resin, AS resin, AAS resin, AC
3 resins, ABS resin, styrene/P-chlorostyrene copolymer, styrene/propylene copolymer, styrene/bugdiene crosslinked polymer, styrene/butadiene/chlorinated paraffin copolymer, styrene/allyl/alcohol copolymer, styrene/butylene Gen rubber emulsion, styrene/maleic acid ester copolymer, styrene/isobutylene copolymer, styrene/maleic anhydride copolymer, acrylate resin or methacrylate resin and its copolymer, styrene/acrylic resin and its copolymer Copolymers, such as styrene/acrylic copolymer, styrene/diethylamino/ethyl methacrylate copolymer,
Styrene-butadiene-acrylic ester copolymer,
Styrene/methyl methacrylate copolymer, styrene/n-butyl methacrylate copolymer, styrene/diethylamino/ethyl methacrylate copolymer, styrene/methyl methacrylate/n-butyl acrylate copolymer, styrene/methyl methacrylate・Butyl arylate/N-(ethoxymethyl)acrylamide copolymer, styrene/glycidyl methacrylate copolymer, styrene/butadiene/dimethyl/aminoethyl methacrylate copolymer, styrene/acrylic acid ester/maleic ester copolymer , styrene/methyl methacrylate/2-ethylhexyl acrylate copolymer, styrene/n-butyl arylate/ethyl glycol methacrylate copolymer, styrene/n-butyl methacrylate/acrylic acid copolymer, styrene/n-
Butyl methacrylate/maleic anhydride copolymer, styrene/butyl acrylate/isobutyl maleic acid half ester/divinylbenzene copolymer, polyester and its copolymer, polyethylene and its copolymer,
One or a blend of two or more of epoxy resins, silicone resins, polypropylene and their copolymers, fluorocarbon resins, polyamide resins, polyvinyl alcohol resins, polyurethane resins, polyvinyl butyral resins, etc. can be used. Moreover, wax etc. can also be used as a substance other than resin. For example, plant-based natural waxes such as candelilla wax, carnauba wax, and rice wax, animal-based natural waxes such as beeswax and lanolin, mineral-based natural waxes such as montan wax and osikelite, and natural natural waxes such as paraffin wax, microcrystalline wax, and petrolatum. Synthetic hydrocarbon waxes such as petroleum waxes, polyethylene waxes and Fischer-Tropsch waxes, modified waxes such as montan wax derivatives and paraffin wax derivatives, hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil conductors, and waxes such as synthetic waxes; Higher fatty acids such as stearic acid and palmitic acid, low molecular weight polyethylene,
One or more types of polyolefins such as polyethylene oxide and polypropylene, olefin copolymers such as ethylene/acrylic acid copolymers, ethylene/acrylic acid ester copolymers, and ethylene/vinyl acetate copolymers are used.

As the coloring agent, black dyes and pigments such as carbon black, spirit black, and nigrosine are used. For colors, dyes or pigments such as phthalocyanine, rhodamine B lake, Solar Pure Yellow 8G, quinacridone, polytungstophosphoric acid, and indathrene blue sulfonamide derivatives can be used. Furthermore,
Dispersants include metal soaps and polyethylene glycol; charge control agents include electron-accepting organic complexes, chlorinated polyesters, nitrofnic acid, quaternary ammonium salts,
Pyridinyl salts and the like can be added. In addition, magnetic powders such as Fe3O4 and Fe are used as magnetic toners.
2Q3, Fe, Cr, Ni, etc. are used.

Further, as the resin fine particles used in the present invention, polymethyl methacrylate, polyethyl methacrylate, polyn
-Butyl methacrylate, polyester, (styrene-butadiene) copolymer (PVC, PVA, PVA
c): 7bo IJ 7- Polyγ-methyl-glutamate, fluororesin, vinylidene fluoride resin, penzoquanamine resin, silicone resin, epoxy resin, Nairoron 6
6/6, nylon 11, nylon 12, polystyrene resin, crosslinked polystyrene resin, phenol resin, melamine resin, polyolefin resin, polyethylene resin, cellulose, etc. are used.

The solvent used to treat particles with fine particles attached to the surface of the inner core particle is determined by the materials of the inner core particle and the fine particles. For this reason, water-based, organic solvent-based, etc. can be used.

This example will be explained in more detail below.

[Example 1] (Preparation of inner core particles) Styrene-acrylic copolymer 44wt%Fe5
Q4 46 wt% carbon black 10 wt% Raw materials having the above composition are kneaded with a twin-screw extruder, cooled and coarsely pulverized.

Next, after finely pulverizing with a jet pulverizer, it is classified to have an average particle size of 1
Inner core particles with a diameter of 0 μm and a distribution of 5 to 25 μm were prepared.

The specific resistance and dielectric constant of the inner core particles were measured.

The measurement method is to fill particles between parallel plate electrodes,
Apply a pressure of g/cm 2 and additionally an electric field of 2k
v/cm was applied to determine the specific resistance. To measure the relative dielectric constant, particles were packed between the electrodes in the same way as in the specific resistance measurement, and the frequency was 1kHz.
It was measured by multiplying by z. As a result, the specific resistance is 5×103Ω
Cm and relative dielectric constant were 400.

(Adhesion of fine particles) Polymethyl methacrylate (PMMA) is used as fine particles.
) with a particle size of 2 μm and a glass transition point of 130°C. The fine particles and the inner core particles were mixed in the composition shown below, and the fine particles were attached to the surface of the inner core particles using a mechanofusion system (manufactured by Koen Micron).The composition and conditions are shown below.

Inner core particles 80wt% PBMA fine particles 40wt% Mechano conditions: rotation speed 19
The treatment was carried out at 0 rpm and for a processing time of 60 minutes. Excess PBMA fine particles that did not contribute to adhesion of the obtained powder particles were removed using a classifier. (Removal of excess PBMA particles using a classifier can be omitted by adjusting the amount of PBMA particles charged.) However, even after removal, the PBMA particles do not peel off and remain attached to the surface of the inner core particles. This was revealed by electron microscopic observation of the surface. In addition, cross-sectional observation using an electron microscope revealed that PBM was present on the surface of the inner core particle.
It was observed that the A particles remained spherical and were embedded.

(Solvent Treatment) The inner core particles to which the fine particles produced by the above method were attached were subjected to a solvent treatment. Acetone was used as the solvent. Contact the powder with this solvent for 3 seconds, then dry at 60°C.
The acetone was evaporated by spray drying. The particles obtained by this solvent treatment had no binding between particles, and each particle was an aggregate in an independent state. In addition, when the cross section of the particles produced in this example was observed using an electron microscope, it was found that
A PBMA resin coating layer of about 1 micron was formed on the surface of the inner core particle. Further, 0.5 wt % of 5in2 fine particles were added to the particles, and the specific resistance was measured in the same manner as in the above method, and it was found to be 5 x 10''0 cm, indicating sufficient electrical insulation.

(Image Evaluation) Using the toner produced by the above method, image formation was evaluated using an image forming system equipped with a general -component magnetic developing machine and having an OPC drum as a photoreceptor. the result,
The maximum allowable range of the development gap for the amount of development to be within the allowable range was 400 μm. Here, the allowable value of the amount of development is determined by the lower limit being the allowable image density, and our standard is the image temperature of 1.4 and the lower limit is 1.2. The upper limit was determined in consideration of the occurrence of poor fixing on the recording paper due to too large an amount of development, and the fact that the number of printable sheets per unit amount of toner would not be significantly lower than the standard due to the increased amount of toner consumption. Based on these facts, the allowable range of development amount is ±20 relative to the standard usage amount.
% or less.

Regarding the improvement of the edge effect, a 1 cm square pattern was developed and evaluated by a plurality of people who visually judged the print quality. The image quality of the toner of this example was evaluated as 4 on a five-level evaluation scale with 1 being the lowest quality and 5 being the highest quality.

(The image evaluation using a conventional two-component developing machine was 4.)
Further, in the toner of this example, the dependence of the image temperature on the developing voltage was almost the same for any developing gap value within the range of the allowable developing gap.

[Example 2] Using the same inner core particles as in Example 1, the thickness of the coating layer was controlled by changing the particle size and composition ratio of the fine particles attached to the inner core particles. Particle size of resin particles is 0°4μm (PBMA)
, particle size 0.8 μm (PMMA), particle size 1.0 μm (
PMMA) was used. Table 1 shows the fine particle adhesion conditions. Next, these particles were treated with a solvent in the same manner as in Example 1. As in Example 1, the particle surface and cross section of the obtained particles were observed using an electron microscope, and the film thickness was measured.

Table 2 shows the processing conditions and results. By changing the particle size and composition ratio of the particles attached to the surface of the inner core particles, as well as the mechano conditions, an insulating coating layer with an arbitrary thickness can be formed. . Furthermore, images were formed and evaluated using the same apparatus as in Example 1 for these toners. The results are shown in Table 3.

Table 1 *processing time: All done in 0 minutes.

Table 2 * Solvent: Acetone Table 3 As shown, if the thickness of the insulating layer is less than 0.5 μm, the electrical insulation will be insufficient, charging will become unstable, and development and transfer will not occur properly. It is thought that it will disappear.

[Example 3] Particles similar to those in Example 1 were used as the inner core particles. Next, for (attachment of fine particles), in this example, a mixed system in which PMMA used in Example 1 and 5i02 fine particles were added was used. The treatment was performed using the Mechafusion system in the same manner as in Example 1. The composition and conditions are shown below.

Inner core particles 80wt% PMMA fine particles 38wt% 5in2 2wt% Mechano conditions: rotation speed 1900 rpm, processing time 6
It took 0 minutes. As in Example 1, the obtained product had PMMA and SiO2 uniformly dispersed attached to the surface of the inner core particle. The particles were subjected to solvent treatment in the same manner as in Example 1. The obtained product showed properties similar to those of Example 1. Furthermore, when this particle was subjected to image formation in the same manner as in Example 1, the same results as in Example 1 were obtained.

[Example 4] The composition of the inner core particles of Example 1 was changed to the following. The rest was carried out in the same manner as in Example 1.

The composition of the inner core particle is shown below.

Oxidized polyethylene wax 4wt% paraffin wax 10wt% polystyrene
10 wt% Fe30570 wt% Carbon black 4 wt% Black titanium dioxide 2 wt% However, the crosstalk was performed using a patch type screw type crosstalk machine. The obtained toner exhibited insulation properties with a specific resistance of 3×10 14 Ωcm. Furthermore, when image evaluation was performed in the same manner as in Example 1, the same results as in Example 1 were obtained.

[Example 5] The experiment was carried out by changing the inner core particles of Example 1 to the following ones.

The rest was carried out in the same manner as in Example 1.

The composition of the inner core particle is shown below.

Oxidized polyethylene wax 4wt% paraffin wax 4wt% polyester
10wt% Fe3O476wt% Carbon black 4wt% Black titanium dioxide 2wt% However, the crosstalk was performed using a patch type screw type mixer and pulverized to 10 μm. The obtained particles had a resistivity of 8x l Q 100cm and a dielectric constant of 3. Next, carbon black was externally added to these particles using a mechanofusion system and fixed on the surface. Conditions are carbon black fi 10 wt%
The processing was carried out at a mechano rotation speed of 160 rpm and a processing time of 30 minutes.

The specific resistance and dielectric constant of the particles externally added with carbon black in this manner were determined by the method shown in Example 1.

As a result, the specific resistance was 2×10 3 ΩCm and the relative permittivity was 350. Next, in Example 1 (attachment of fine particles) to the particles,
(solvent treatment) to produce a toner. The obtained particles exhibited an insulating property of 3 x 10"0 cm. Furthermore,
When an image was formed in the same manner as in Example 1, the same effect as in Example 1 was obtained.

Compared to Example 4, the toner of this example is characterized by the fact that normal carbon black, which is not a type that imparts conductivity, can be used as a raw material to produce particles with high dielectric properties, so the viscosity of the toner can be lowered when melted. There are things you can do.

Therefore, the fixing temperature at which the toner is fixed onto the recording paper can be lowered.

[Example 6] As another example, an inner core particle was produced by the following method and manufacturing method. Fine particles of terephthalic acid, hexamethylene diol, glycerin as a binding material, magnetite as a coloring agent and magnetic material, and barium titanate as a ferroelectric material are mixed and dispersed in a colloid mill, and the resulting dispersion is heated and depressurized. A crosslinked polyester resin block was obtained. The composition of this block is shown below.

Polyester resin 30wt% magnetite 45wt% barium titanate
At this time, the relative dielectric constant of this resin block was 230. Next, the resin block is mechanically crushed to obtain crushed pieces, then dispersed in an aqueous liquid and crushed in a colloid mill, the aqueous liquid is removed, and after drying, the maximum particle size is 1 μm, the average particle size is 0.3 ~ Ferroelectric fine particles of 0.5 μm were obtained. 100wt% of these ferroelectric fine particles were added to 15w of polyester resin.
t% using a patch type screw mixer. This polyester resin is a material that melts at a low temperature with a glass transition point of 40'C, and even if it contains a large amount of solids, it has a low viscosity when melted, making it easy to heat fix. The obtained mixture was cooled and pulverized using a jet air pulverizer, and the particle size distribution was controlled using an air classifier to obtain particles having an average particle size of 10 μm. Using the thus obtained inner core particles, a resin coating layer was formed on the surface in the same manner as in Example 1.

Thereafter, SiO2 fine particles were externally added as a charge control agent to prepare a one-component insulating magnetic toner. The specific resistance of the obtained toner was 7×10100, indicating sufficient electrical insulation. The thus obtained toner was evaluated for image formation in the same manner as in Example 1, and the same results as in Example 1 were confirmed.

[Example 7] The ferroelectric fine particles with an average particle size of 0.3 to 0.5 μm obtained in Example 6 were mixed with styrene monomer using a colloid mill.
After preparing a uniformly dispersed solution in a mixed solution of acrylic monomers, an average particle size of 10 μm was obtained using a known suspension polymerization method using BP○ as a polymerization initiator, such as that disclosed in Japanese Patent Publication No. 36-10231. The composition of styrene acrylic particles in which ferroelectric fine particles were dispersed is shown below.

Styrene acrylic resin 15 wt% Ferroelectric fine particles 85 wt% A resin coating was formed on the surface of the inner core particles prepared by the above method in the same manner as in Example 1, and -
A component-insulating magnetic toner was prepared. The specific resistance of the obtained toner was 5×10 14 Ω, indicating sufficient electrical insulation.

When the thus obtained toner was evaluated for image formation in the same manner as in Example 1, the same results as in Example 1 were obtained.

Although the embodiments have been described above, the present invention is not limited to the above embodiments, and the insulating resin layer is formed using various kinds of resins, and furthermore, a coloring agent, a charge control agent, Toner components such as fluidity improvers can also be added.

[Effects of the Invention] As described above, according to the toner manufacturing method of the present invention, -
In the component magnetic development method, toners that can obtain excellent image quality with less development gap dependence and less edge effects than before, are made of various resin components regardless of the composition and structure of the core particles. This method has a great effect in that a multilayer structure toner having a desired dielectric constant can be produced by uniformly and easily controlling the thickness of the coating layer. Therefore, the toner manufacturing method of the present invention can reduce the mechanical precision required for the developing section of an image forming apparatus, and can further contribute to reducing the cost of the image forming apparatus. Low-cost small-sized electrophotographic printer It is possible to realize low-cost small-sized electrophotographic copying machines, low-cost small-sized facsimile machines, etc. In addition, because precision regulations are loose, large-sized image forming devices, such as low-priced large-format CAD output devices, large-sized It is also possible to apply it to image displays, etc., and its application fields are extremely wide.

[Brief explanation of drawings]

FIG. 1 is a flowchart of the toner manufacturing method of the present invention. 1...Binder resin 2...Coloring agent ・Resin fine particles ·solvent ・Inner core particle ・External addition processing ・Resin fine particles externally added inner core particles ・Coating treatment ・Resin shell toner

Claims (1)

[Claims] It is composed of at least a binder resin and a colorant, has at least a two-layer structure, and the outermost shell layer exhibits electrical insulation;
and in a toner in which the effective dielectric constant of the inner core particles is higher than the dielectric constant of the outermost shell layer, a step of using at least resin fine particles to form the outermost shell layer and adhering the fine particles to the surface of the inner core particles; A toner manufacturing method comprising the step of forming an outermost shell layer made of the resin fine particle component by treating with a solvent that dissolves the resin.