JPH0619201A - Production of toner - Google Patents

Abstract

PURPOSE:To produce a toner capable of preventing the abrasion of a screen mesh, maintaining desired charging performance, powder characteristic, etc., and capable of stably removing the aggregates and coarse grains over a long period. CONSTITUTION:The toner grains having 2-15mum weight average diameter and an external additive are mixed to prepare a toner, and the toner is passed through a twill-fabric screen satisfying the following conditions to produce the toner. Namely, 0.05<=d(mm)<=0.208, 100<=W(mum)<=180 and 7.9X10<-4=d(mm)/W (mum)<=9.1X10<-4>, where (d) is the average diameter of the wires constituting the screen, and W is the opening of the screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner used in image forming methods such as electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, a thermoplastic resin and a colorant (for example, a dye, a pigment, a magnetic powder, etc.) are heated and melted and kneaded to form a uniform dispersion, which is then cooled and kneaded. A fine powder (that is, toner particles) having a predetermined particle size and particle size distribution is prepared through a crushing process for crushing and a classification process for classifying the crushed product as necessary. Further, in order to continue the stable image formation in the developing process of the copying machine, the transferring process, and the cleaning process of removing the untransferred toner from the photosensitive member, the fluidity of the toner, the charging stability,
The toner is manufactured through a step of mixing the toner particles with an external additive such as an inorganic fine powder or an organic fine powder for the purpose of improving properties such as lubricity and cleaning property.

However, in these steps, coarse particles, fused coarse particles due to mechanical heat generation, and reaggregates due to van der Waals force are generated, and the coarse particles and the reaggregates are minute in the developing machine. This may cause clogging of the gap or cause various image defects as particles with poor charging. To remove coarse particles and reaggregates, for example, 100 mesh openings
Processes such as passing through a sieve of ˜250 μm are performed. As a device having a screen, for example, there is a multi-stage gyro shifter, and as a vibration method, there are mechanical vibration and ultrasonic vibration.

By such a method, coarse particles and reaggregates can be removed for the time being, but at present, there are some points to be improved in production stability and toner quality. There is. For example, if the sieve is used for a long time, the wire forming the mesh is worn due to the friction between the toner particles and the mesh of the sieve, the mesh is widened, or the wire is damaged, and the purpose cannot be achieved. Happens. In particular, in the case of a magnetic toner containing magnetic powder in the toner particles, or in a toner in which inorganic fine powder or organic fine powder having high hardness and high abrasiveness is mixed with the toner particles, the wire wear becomes large. Further, in recent years, in order to pursue higher definition image quality, the toner particle size tends to be smaller, and the increase in the specific surface area of the toner per unit weight increases the number of times of contact with the mesh wire. When the wire diameter is reduced to reduce the openings for effective removal of coarse particles and reaggregates,
It causes the problem of accelerating wire wear.

Various vibrations are applied to the mesh in order to allow the toner particles and the external additives to pass through the sieve efficiently.

However, when the conventional plain weave net sieve is vibrated to allow the toner to pass, the shape of the toner particle surface is easily deformed, and the dispersed state of the external additive in the toner and the external additive and the toner particle are In some cases, the adhesion state of the toner changes, and as a result, the charging characteristics and powder characteristics of the toner change, and the toner characteristics deteriorate.

Therefore, there is a demand for a method of efficiently performing the sieve treatment of the toner after the external addition step without deteriorating the characteristics of the toner.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner capable of stably removing aggregates and coarse particles over a long period of time.

A further object of the present invention is to provide a manufacturing method for preventing abrasion of a mesh of a sieve for removing agglomerates and coarse particles and for allowing a toner to pass through efficiently.

Further, an object of the present invention is to produce a toner capable of obtaining a stable image quality while the toner retains desired charging performance and powder characteristics in the process for removing aggregates and coarse particles. To provide a method.

A further object of the present invention is to provide a method for producing a toner in which even a magnetic toner containing a magnetic substance causes less abrasion of the screen of the sieve.

Further, an object of the present invention is to provide a method for producing a toner having less abrasion of the mesh of a sieve even in the case of a toner in which an inorganic fine powder or an organic fine powder having abrasiveness is externally added to toner particles. is there.

A further object of the present invention is to provide a method for producing a toner in which the mesh of the sieve is less worn even in the case of a toner having a small particle size.

[0014]

According to the present invention, a toner is prepared by mixing toner particles having a weight average particle diameter of 2 to 15 μm and an external additive, and the prepared toner is subjected to the following condition: 0.05 ≦ d [mm] ≤ 0.208 100 ≤ W [μm] ≤ 180 7.9 x 10 ^-4 ≤ d [mm] / W [μm] ≤ 9.1 x 10 ^-4 [where d is used for the sieve] The average particle diameter of the wire forming the mesh is represented by W, and W is the mesh size of the sieve.], And a method for producing a toner is characterized by passing through a sieve of a twill mesh.

The twill weave net is generally used for a fine net sieve having an opening of 65 μm or less, but the present inventors have studied and found that the net opening is 100 to 180.
The present inventors have found that the use of a twill net having a large size of μm for a sieve makes it possible to efficiently produce a toner having good electrophotographic characteristics, and has reached the present invention.

In the present invention, the toner particles are mixed with an external additive to obtain a toner composition (that is, a toner), which is then sieved. As the sieve to be used, a sieve having a twill weave mesh shown in FIG. 1 is used. Weight average particle size 2-15μ
In the case of toner particles of m, the average diameter d of the wire forming the net is preferably 0.052 to 0.208 mm, and the average mesh opening W of the net is preferably 100 to 180 μm. If the average diameter d of the wire is less than 0.052 mm, the durability of the screen tends to be poor, while if it exceeds 0.208 mm, the toner staying on the screen tends to be too long. When the average mesh opening W of the mesh is less than 100 μm, the external additive is easily released from the toner particle surface,
On the other hand, when it exceeds 180 μm, there is a high possibility that coarse particles are mixed in the toner. The average diameter d of the wire is preferably 0.080 to 0.180 mm, and the average mesh opening of the mesh is preferably 106 to 170 μm.

The average diameter d of the wire of the mesh of the sieve is obtained by measuring the diameters of the wire at 5 points or more in the vertical line direction and at 5 points or more in the horizontal line of the whole mesh, and obtaining the average value. At that time, the screen is magnified 100 times and measured.

The average mesh opening W of the screen of the sieve is the value obtained by measuring the length including 10 or more sieves at 5 or more points in the vertical line direction and dividing the measured length by the number of sieves. The value obtained by subtracting the average diameter d of the wire was obtained, and in the same manner, the length including 10 or more sieves was measured at 5 or more points in the horizontal direction,
The value obtained by dividing the measured length by the number of sieves minus the average diameter d of the wire is obtained, and the average value is obtained. Examples of the material of the wire include metal and resin (for example, polyamide resin), and a metal wire such as stainless steel is preferable from the viewpoint of durability.

The d / W of the sieve is preferably 7.9 × 10 ^{−4 to} 9.1 × 10 ⁻⁴ , more preferably 8.1 × 10 ⁻⁴ to from the viewpoint of toner productivity and toner quality. 9.1 x 1
^0-4 is good.

The screen twill weave mesh used in the present invention has a structure in which rectangular meshes are combined to form a square mesh as shown in FIG. It is easy to pass the toner without changing the external addition state of the agent. Therefore, in the production direction of the present invention, the productivity of the toner is excellent, the durability of the screen of the sieve is good, and the electrophotographic characteristics of the obtained toner are also excellent.

On the other hand, in the case of the plain weave net, only the square mesh is used, and the toner hardly passes through the net,
The external addition state of the external additive is apt to change when passing through the net, and the net is more likely to be damaged by abrasion as compared with the twill weave.

When the external additive is externally added to the toner particles, a powder mixing device such as a Henschel mixer is preferably used.

A device equipped with a sieve includes a vibrating screen and a gyro shifter.

The sieve preferably has a turning radius of 5 to 100 mm and is moved at a turning number of 50 to 500 rpm.

As the binder resin for the toner particles, for example,
The following are listed.

Homopolymers or copolymers of the following vinyl monomers: styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene,
3,4-dichlorostyrene, p-ethylstyrene, 2,
4-dimethylstyrene, pn-butylstyrene, p-
Derivatives of styrene such as tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene; ethylene, propylene, butylene. , Ethylenically unsaturated monoolefins such as isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid. Methacrylic acid esters such as stearyl, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate. , Dodecyl acrylate, ethylhexyl acrylate,
Stearyl acrylate, 2-chloroethyl acrylate,
Acrylic esters such as phenyl acrylate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone; N-vinyl pyrrole, N
-N-vinyl compounds such as vinylcarbazole, N-vinylindole and N-vinylpyrrolidone; vinylnaphthalenes; acrylic acid derivatives or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; acrylic acid; methacrylic acid, maleic acid ,
Vinyl compound derivatives having a carboxyl group such as fumaric acid; maleic acid-half esters, half esters such as fumaric acid half esters; maleic anhydride, maleic acid esters, fumaric acid ester derivatives.

Further, polyester, polyurethane, epoxy resin, polyvinyl butyral, rosin, modified rosin, chill pen resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, haloparaffin,
Paraffin wax.

These polymers, resins or waxes are
Used alone or as a mixture.

Of these, styrene resins, acrylic resins, and polyester resins are particularly preferably used as the binder resin in consideration of the developing characteristics of the toner.

The binder resin as described above is more preferably a vinyl-based polymer, a vinyl-based copolymer or a mixture thereof cross-linked with a cross-linking agent in consideration of offset resistance as a toner.

As the binder resin for the toner used in the pressure fixing system, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-
Acrylic ester copolymers, higher aliphatics, polyamide resins, and polyester resins can be mentioned. These are preferably used alone or as a mixture.

In the case of a magnetic toner, the magnetic material of the magnetic powder contained in the magnetic toner particles includes iron oxides such as magnetite, maghematite and ferrite; iron oxides containing other metal oxides; Fe, Co and Ni. Such metals; these metals and Al, Co, Cu, Pb, Mg, Ni, Sn,
Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, T
alloys with metals such as i, W, V; and mixtures thereof.

The magnetic powder has an average particle size of 0.1 to 0.5 μm, preferably 0.1 to 0.3 μm. The amount of the magnetic powder to be contained in the magnetic toner is 4 with respect to 100 parts by weight of the resin component.
0 to 150 parts by weight, preferably 60 to 120 parts by weight with respect to 100 parts by weight of the resin component.

In the non-magnetic toner, as a colorant,
Any suitable pigment or dye may be used.

In order to improve the triboelectric charging characteristics of the toner, it is preferable to use a charge control agent internally added to the toner. Known positive charge control agents can be used. For example, a modified product of nigrosine and a fatty acid metal salt thereof, an organic quaternary ammonium salt, diorganotin oxide, diorganotin borate and the like can be used alone or in combination of two or more kinds. Among these, nigrosine compounds and organic quaternary ammonium salts are particularly preferably used.

Known negative charge control agents can be used. For example, carboxylic acid derivatives and their metal salts, alkoxylates, organometallic complexes, chelate compounds and the like can be used alone or in combination of two or more kinds. Among these, acetylacetone metal complex, salicylic acid metal complex, alkylsalicylic acid metal complex, dialkylsalicylic acid metal complex, naphthoic acid metal complex, and monoazo metal complex are particularly preferably used.

The toner particles have a weight average particle diameter of 2 to 15 μm (preferably 4 to 12) from the viewpoint of resolution and developability.
μm) is good.

The weight average particle diameter of the toner particles is measured, for example, by the following measuring method.

A Coulter counter T is used as a measuring device.
An interface (made by Nikkaki) and a CX that outputs number distribution and volume distribution using A-II type (made by Coulter)
-1 Connect a personal computer (made by Canon),
As the electrolytic solution, a 1% NaCl aqueous solution is prepared using first grade sodium chloride. As a measuring method, the electrolytic aqueous solution 100 to
0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) as a dispersant is added to 150 ml,
Further, 2 to 20 mg of a measurement sample (about 30,000 to about 300,000 particles) is added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the Coulter counter TAII type uses a 100 μ aperture as an aperture, and a particle size distribution of particles of 2 to 40 μ based on the number. Is measured and the weight-based weight average diameter value obtained from the volume distribution is obtained.

Examples of additives (that is, external additives) mixed with toner particles include inorganic fine powder, surface-treated inorganic fine powder and organic fine powder.

Examples of the inorganic fine powder include inorganic oxide fine powder and carbonate compound fine powder. As the inorganic oxide, alumina, zinc oxide, tin oxide, titanium oxide, double oxide (strontium titanate or barium titanate,
Calcium titanate, strontium zirconate, calcium zirconate, etc.). Examples of the carbonate compound include calcium carbonate and magnesium carbonate. Among these, a double oxide of titanium oxide, particularly fine powder of strontium titanate, exhibits excellent effects.

The external additive preferably has a BET specific surface area of 0.5 to 400 m ² / g measured by a nitrogen gas adsorption method.

Further, the BET specific surface area 40 to 400 m ² /
g of colloidal silica fine powder, hydrophobic colloidal silica fine powder, alumina fine powder, hydrophobic alumina fine powder, titanium oxide fine powder and hydrophobic titanium oxide fine powder are used to improve the fluidity of toner particles. Preferred as an additive are strontium titanate fine powder and cerium oxide having a BET specific surface area of 0.5 to 30 m ² / g (more preferably 0.8 to 15 m ² / g) as an abrasive. Preferred as a toner microcarrier.

It is also preferable to use two or more kinds of external additives in combination in order to improve various characteristics of the toner.

If necessary, additives other than the above may be mixed. Examples of such additives include lubricants such as Teflon, polyvinylidene fluoride and fatty acid metal salts; abrasives such as silicon carbide; fluidity imparting agents or anti-caking agents; carbon black or fixing aids such as low molecular weight polyethylene. Is mentioned. For the purpose of improving the releasability at the time of heat roll fixing, a wax-like substance such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, and sazol wax is added to the toner of the present invention in an amount of 0.5 to 5% by weight. % May be added.

In the production of a toner, the above-mentioned toner constituent materials are thoroughly mixed by a mixer and then well kneaded by using a heat kneader such as a heat roll kneader or an extruder, and the kneaded product is cooled and solidified. It is preferable that the toner particles are obtained by pulverizing, classifying the pulverized product, and mixing the toner particles with an additive to obtain a toner. Another method is to obtain toner particles by dispersing constituent materials in a binder resin solution and then spray-drying; emulsifying suspension by mixing a predetermined material with a monomer that constitutes the binder resin. There is a method of producing toner particles by a polymerization method in which a toner is obtained by polymerizing the liquid. The toner particles according to the present invention may be microcapsule toner particles composed of a core material and a shell material.

[0047]

EXAMPLES The present invention will be described in detail below with reference to specific examples. The present invention is not limited to these.

Example 1 Styrene / butadiene resin 100 parts by weight Magnetic iron oxide (average particle size 0.2 μm) 90 parts by weight Nigrosine dye 2 parts by weight

After uniformly mixing the above materials in a Henschel mixer, they are melted and kneaded by heating with a twin-screw type extruder, and the cooled kneaded product is roughly crushed to about 100 μm to obtain a coarsely crushed product, which is crushed by jet crushing. Finely pulverized by a machine to obtain a finely pulverized product, and the finely pulverized product was adjusted to a desired particle size distribution by a classifier to obtain a black fine powder [magnetic toner particles (A)] having a weight average particle size of 7 μm.

To a Henschel mixer with a capacity of 75 liters, 97.7 wt% of magnetic toner particles (A), 0.3 wt% of hydrophobic colloidal silica fine powder and 2 wt% of strontium titanate fine powder were added, and the rotation speed of the stirring blade was changed. 1
Magnetic toner (A) was obtained by stirring and mixing at 800 rpm for 5 minutes. The hydrophobic colloidal silica fine powder had a BET specific surface area of 200 m ² / g measured by a nitrogen adsorption method, and the strontium titanate had a BET specific surface area of 2.4 m ² / g.

From the obtained magnetic toner (A), in order to remove fused substances, coarse particles, reaggregates and the like in the production process,
The average opening W is 112 μm, and the average diameter d of the wire is 0.
A sieve having a twill-woven stainless steel mesh of 100 mm and d / W of 8.93 × 10 ⁻⁴ (120 Meshes
Gyro shifter equipped with per Linear Inch (sifter, turning radius 30 mm, turning number 230 r
The amount of magnetic toner (A) processed is 5 kg.
The magnetic toner (A-a) was obtained by passing the toner at a rate of / m ² · min.

Even after running for a total of 500 hours, the screen of the sieve was not damaged, and the magnetic toner (Aa) was not mixed with coarse powder, fused material, or reaggregated material.

The magnetic toner (A-a) passed through the sieve was put into a Canon copier NP2020, and the toner was cooled to room temperature and humidity (temperature 23).
When images were printed at a temperature of 60 ° C. and a humidity of 60% RH, image deficiencies such as fog and reverse fog were not observed at an image density of 1.35.

After the copying machine was left in a high temperature and high humidity environment (temperature 32.5 ° C., humidity 85% RH) overnight, images were printed in a room temperature and normal humidity environment. Concentration is 1.31
However, the image density recovered to 1.35 on the 10th sheet.

Comparative Example 1 In the same manner as in Example 1, 97.7 wt% of magnetic toner particles (A), 0.3 wt% of hydrophobic colloidal silica fine powder and 2 wt% of strontium titanate fine powder were placed in a 75 liter Henschel mixer. Add and mix with stirring blade rotation speed 1800 rpm for 5 minutes to mix magnetic toner (A)
Got

The average opening W of the obtained magnetic toner (A)
Is 125 μm, the average diameter d of the wire is 0.087 mm,
Sieve having a plain weave stainless steel mesh with a d / W of 6.96 × 10 ⁻⁴ (120 Meshes per Line
The magnetic toner (A-b) was obtained by allowing the magnetic toner (A) to pass through at a treatment rate of 5 kg / m ² · min using a gyro shifter equipped with an Ar inch). After a total of 50 hours of operation,
The screen mesh was damaged due to wear.

When the magnetic toner (Ab) was placed in a Canon copier NP2020 and image formation was carried out at room temperature and normal humidity, the image density was 1.30.

When the copying machine was left in a high temperature and high humidity environment overnight and imaged in a normal temperature and normal humidity environment, the image density of the first image was 1.15, and that of the 10th image was Image density is 1.
The image density was 20, and the image density finally recovered to 1.30 on the 50th sheet.

Comparative Example 2 The average opening W of the magnetic toner (A) not passed through the sieve is 1
11 μm, average diameter d of wire is 0.070 mm, d /
Sieve with plain weave stainless steel mesh W = 6.31 x 10 ^-4 (140 Meshes per Linea
A magnetic toner (A-c) was obtained by passing the magnetic toner (A) at a throughput of 5 kg / m ² · min with a gyro shifter equipped with r Inch). After 30 hours of operation in total, the mesh of the sieve was damaged by abrasion.

When the magnetic toner (A-c) was placed in a Canon copier NP2020 and image formation was carried out at room temperature and normal humidity, the image density was 1.30.

When the copying machine was left in a high temperature and high humidity environment overnight and imaged in a normal temperature and normal humidity environment, the image density of the first image was 1.20, and that of the 10th image was Image density is 1.
The image density was 25, and the image density finally recovered to 1.30 on the 50th sheet.

Example 2 Styrene / n-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide (average particle size 0.19 μm) 60 parts by weight Nigrosine dye 2 parts by weight Low molecular weight wax 5 parts by weight

After uniformly mixing the above materials with a Henschel mixer, the mixture was heated and melted and kneaded with a twin-screw type extruder, and the cooled kneaded product was roughly crushed to about 100 μm to obtain a coarsely crushed product, which was jet-crushed. Finely pulverized by a machine to obtain a finely pulverized product, and the finely pulverized product was adjusted to a desired particle size distribution by a classifier to obtain a black fine powder [magnetic toner particles (B)] having a weight average particle diameter of 12 μm.

In a Henschel mixer having a capacity of 75 liters, 97.5 wt% of magnetic toner particles (B), 0.5 wt% of hydrophobic colloidal silica and BET specific surface area of 5 m ² /
2 wt% of cerium oxide fine powder (g) was added, and the mixture was stirred and mixed at a rotation speed of a stirring blade of 1800 rpm for 5 minutes to obtain a magnetic toner (B). In order to remove fused substances, loose substance coarse particles, reaggregated substances and the like in the production process from the obtained magnetic toner (B), the average opening W is 152 μm, the average diameter d of the wire is 0.13 mm, and d / W is Sieve with 8.55 × 10 ^-4 twilled stainless steel mesh (90 Meshe
A gyro shifter equipped with a Sperper Linear Inch) and a processing amount of magnetic toner (B) of 5 kg / m.
^After passing for ² minutes, a magnetic toner (Ba) was obtained. Even after operating for a total of 500 hours, there was no damage to the screen of the sieve, and neither the coarse powder, the fused material nor the re-aggregated material was mixed in the magnetic toner (Ba).

When the magnetic toner (Ba) which passed through the sieve was put into a Canon copying machine NP2020 and image formation was carried out at room temperature and normal humidity, the image density was 1.30, and image defects such as fog and reverse fog did not occur. I couldn't see it.

After the copying machine was left in a high temperature and high humidity environment (temperature 32.5 ° C., humidity 85% RH) overnight, images were printed in a room temperature and normal humidity environment. Concentration 1.26
However, the image density recovered to 1.30 on the 10th sheet.

Comparative Example 3 The average opening W of the magnetic toner (B) not passed through the sieve was measured.
Is 162 μm, the average diameter d of the wire is 0.120 mm,
Sieve having a plain weave stainless steel mesh with d / W of 7.4 × 10 ⁻⁴ (90 Meshes per Linear)
A magnetic toner (B-b) was obtained by passing the magnetic toner (B) at a throughput of 5 kg / m ² · min using a gyro shifter equipped with an Inch). After a total of 90 hours of operation, the mesh of the sieve was damaged due to wear.

When the magnetic toner (Bb) was put into a Canon copier NP2020 and image formation was carried out at room temperature and normal humidity, the image density was 1.24.

After the copier was left in a high temperature and high humidity environment overnight, images were printed in a room temperature and normal humidity environment. The image density of the first image was 1.15, and that of the 10th image was Image density is 1.
The image density was 20, and the image density finally recovered to 1.24 on the 50th sheet.

Comparative Example 4 The magnetic toner (B) which has not been passed through the sieve is compared with the average opening W
Is 132 μm, the average diameter d of the wire is 0.150 mm,
A sieve having a twill weave stainless steel mesh with a d / W of 11.36 × 10 ⁻⁴ (90 Meshes per Lin)
A magnetic toner (B-c) was obtained by allowing the magnetic toner (B) to pass through at a treatment rate of 5 kg / m ² · min using a gyro shifter equipped with an ear inch). After a total of 110 hours of operation, the mesh of the sieve was damaged due to wear.

When the magnetic toner (B-c) was placed in a Canon copier NP2020 and image formation was carried out at room temperature and normal humidity, the image density was 1.20.

After the copier was left in a high temperature and high humidity environment overnight, images were printed in a normal temperature and normal humidity environment. The image density of the first image was 1.12 and that of the 50th image was 50%. Image density is 1.2
It finally recovered to 0.

Example 3 Magnetic toner particles (B) prepared in Example 2 99.7 wt.
% And hydrophobic colloidal silica fine powder 0.3 wt% were mixed by stirring with a Henschel mixer to obtain a magnetic toner (C). The average opening W of the obtained magnetic toner (C) is 1
34 μm, wire average diameter d 0.120 mm, d / W
Having a twill weave of stainless steel mesh of 8.96 × 10 ⁻⁴ (100 Meshes per Linea
A magnetic toner (C-a) was obtained by passing the magnetic toner (C) at a throughput of 5 kg / m ² · min with a gyro shifter equipped with rInch). Even after operating for a total of 500 hours, the screen of the sieve was not damaged, and neither the coarse powder, the fused material nor the reaggregate was mixed in the magnetic toner (Ca).

When an image of the magnetic toner (Ca) was printed by a Canon copying machine NP2020, the image density was 1.
At 30, no image defects such as fog and reversal fog were observed.

After the copying machine was left in an environment of high temperature and high humidity (temperature: 32.5 ° C., humidity: 85% RH) overnight, images were printed in a room temperature and normal humidity environment. Concentration is 1.2
Although it was 3, the image density on the 10th sheet was restored to 1.30.

Comparative Example 5 The magnetic toner C prepared in Example 3 has an average opening W of 1
40 μm, average wire diameter d is 0.114 mm, d / W
Having a plain weave stainless steel mesh of 8.14 × 10 ⁻⁴ (100 Meshes per Linear
The magnetic toner (C-b) was obtained by passing the magnetic toner (C) at a throughput of 5 kg / m ² · min using a gyro shifter equipped with an Inch).

When the magnetic toner (Cb) was put into a Canon copier NP2020 and image formation was carried out at room temperature and normal humidity, the image density was 1.27.

After the copier was left in a high temperature and high humidity environment overnight, images were printed in a normal temperature and normal humidity environment. The first image printed had an image density of 1.20, and the 50th image was printed. Image density is 1.2
Finally recovered to 7.

[0079]

[Table 1]

[0080]

According to the present invention, abrasion of the sieving mesh can be prevented, the toner can be maintained at desired charging performance and powder characteristics, and agglomerates and coarse particles can be stably removed over a long period of time. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a twill weave.

FIG. 2 is an explanatory diagram of plain weave.

FIG. 3 shows a general toner manufacturing flow.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number for FI Technical location G03G 9/08 G03G 9/08 375 (72) Inventor Masayoshi Uchiyama 3-30 Shimomaruko, Ota-ku, Tokyo No. 2 Canon Inc.

Claims (3)

[Claims] 1. A toner is prepared by mixing toner particles having a weight average particle diameter of 2 to 15 μm and an external additive, and the prepared toner is subjected to the following conditions: 0.05 ≦ d [mm] ≦ 0.208 100 ≦ W [μm] ≦ 180 7.9 × 10 ⁻⁴ ≦ d [mm] / W [μm] ≦ 9.1 × 10 ⁻⁴ [In the formula, d is the average of the wires constituting the mesh used in the sieve] The method for producing a toner is characterized in that the toner is passed through a twill weave mesh sieve which satisfies the following formula: 2. The method for producing a toner according to claim 1, wherein the toner particles are formed of magnetic toner particles, and the external additive is formed of an inorganic oxide fine powder. 3. The external additive is formed of strontium titanate fine powder and colloidal silica fine powder.
Alternatively, the method for producing the toner according to claim 2.