JP2887042B2 - Manufacturing method of toner - Google Patents

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 an image forming method such as electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art As shown in FIG. 3, generally, a thermoplastic resin and a colorant (for example, a dye, a pigment, a magnetic powder, etc.) are heated and melt-kneaded to form a uniform dispersion. Through a pulverizing step for pulverizing and, if necessary, a classifying step for classifying the pulverized product, a fine powder (that is, toner particles) having a predetermined particle size and particle size distribution is prepared. Further, in order to continue stable image formation in a developing process, a transferring process, and a cleaning process of removing untransferred toner from a photoconductor, the fluidity, charging stability,
A toner is produced through a process of mixing an external additive such as an inorganic fine powder or an organic fine powder with toner particles for the purpose of improving properties such as lubricity and cleaning properties.

However, in these processes, coarse particles, fused coarse particles due to mechanical heat generation, and re-aggregates due to Van der Waals force are generated, and the coarse particles and the re-aggregates are minute particles in the developing machine. This may cause clogging in the gaps or various image defects as poorly charged particles. In order to remove coarse particles and re-agglomerates, for example,
A step of passing through a sieve of ~ 250 µm is performed. As a device having a sieve, for example, there is a multi-stage gyro shifter, and as a vibration method, there is mechanical vibration or ultrasonic vibration.

Although such a method makes it possible to remove coarse particles and re-agglomerates for the time being, at present, there are some points to be improved in production stability and toner quality. I have. For example, if the sieve is used for a long time, the wire forming the net will be worn due to the rubbing between the toner particles and the screen of the sieve, and the openings will be large, or the wire will be broken, and the object cannot be achieved. Happens. In particular, in the case of a magnetic toner containing a magnetic powder in the toner particles, or in a toner in which a high-hardness inorganic or organic fine powder is mixed with the toner particles, the abrasion of the wire is increased. Furthermore, 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 wire of the net. When the wire diameter is reduced to reduce the aperture for effective removal of coarse particles and re-agglomerates,
There is a problem that hasten the abrasion of the wire.

[0005] In order to efficiently pass toner particles and external additives through a sieve, various kinds of vibrations are applied to a mesh.

However, when the conventional plain weave mesh sieve is vibrated to allow the toner to pass through, the shape of the toner particle surface is easily deformed, and the dispersion state of the external additive in the toner and the external additive and toner particles Of the toner, and as a result, the charging characteristics and the powder characteristics of the toner may change and the characteristics of the toner may decrease.

Therefore, there is a need for a method of efficiently sieving 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 removing aggregates and coarse particles stably over a long period of time.

It is a further object of the present invention to provide a manufacturing method for preventing abrasion of a screen of a sieve for removing aggregates and coarse particles and allowing toner to efficiently pass therethrough.

It is another object of the present invention to provide a method for producing a toner capable of obtaining a stable image quality while maintaining desired charging performance and powder characteristics in a process for removing aggregates and coarse particles. It is to provide a method.

It is a further object of the present invention to provide a method for producing a toner having less abrasion of a sieve net even in the case of a magnetic toner containing a magnetic substance.

It is a further object of the present invention to provide a method for producing a toner in which a sieve mesh is less worn even when a toner obtained by externally adding an inorganic fine powder or an organic fine powder having abrasive properties to toner particles. is there.

It is a further object of the present invention to provide a method for producing a toner having less abrasion of a sieve net 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 × 10 ⁻⁴ ≦ d [mm] / W [μm] ≦ 9.1 × 10 ^-4 [where d is used for a sieve Indicates the average particle size of the wire constituting the mesh, and W indicates the mesh size of the screen.

A twill net is generally used for a fine net sieve having a mesh size of 65 μm or less. However, the present inventors have studied and found that the mesh size is 100 to 180.
The inventors have found that the use of a twill net having a size as large as μm for a sieve enables the efficient production of a toner having good electrophotographic properties, and has reached the present invention.

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

The average diameter d of the wire of the screen of the sieve can be obtained by measuring the diameters of the wires at 5 or more in the vertical direction and 5 or more in the horizontal direction of the entire net and calculating the average value. At this time, the measurement is performed by enlarging the net by 100 times.

The average opening W of the sieve mesh is obtained by measuring the length including 10 or more sieves in five or more vertical directions and dividing the measured length by the number of sieves as described above. The value obtained by subtracting the average diameter d of the wire is obtained, and similarly, the length including 10 or more sieves is measured at 5 or more locations in the horizontal direction,
The value obtained by subtracting the average diameter d of the wire from the value obtained by dividing the measured length by the number of sieves is obtained, and the average value thereof is obtained. Examples of the material of the wire include a metal and a 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 from 7.9 × 10 ^{-4 to} 9.1 × 10 ^-4 , more preferably from 8.1 × 10 ^-4 from the viewpoint of toner productivity and toner quality. 9.1 × 1
0 ^-4 is good.

The twill net of the sieve 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 let the toner pass without changing the externally added state of the agent. Therefore, in the production direction of the present invention, the toner productivity is excellent, the durability of the sieve net is good, and the electrophotographic properties of the obtained toner are also excellent.

On the other hand, in the case of a plain-woven net, only a square mesh is used, and the toner hardly passes through the net.
The external additive state of the external additive is liable to change when passing through the net, and the net is also easily damaged by abrasion as compared with the twill weave.

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

Examples of a device equipped with a sieve include a vibrating sieve and a gyro shifter.

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

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

A homopolymer or copolymer 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-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene; 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 Methacrylates 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,
Acrylates such as 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 vinyl isopropenyl ketone; N-vinyl pyrrole;
N-vinyl compounds such as vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; acrylic 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 ester, half ester such as fumaric acid half ester; maleic anhydride, maleic ester, fumaric ester derivative.

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 in combination.

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

Examples of the binder resin for the toner to be subjected to the pressure fixing method include low-molecular-weight polyethylene, low-molecular-weight polypropylene, ethylene-vinyl acetate copolymer, and ethylene-vinyl acetate.
Acrylic ester copolymers, higher aliphatic, polyamide resins and polyester resins are exemplified. These are preferably used alone or as a mixture.

In the case of the 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; 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 diameter of 0.1 to 0.5 μm, preferably 0.1 to 0.3 μm. The amount of the magnetic powder contained in the magnetic toner is 4 parts by weight per 100 parts by weight of the resin component.
0 to 150 parts by weight, preferably 60 to 120 parts by weight based on 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, nigrosine and its modified products such as fatty acid metal salts, organic quaternary ammonium salts, diorganotin oxide, diorganotin borate and the like can be used alone or in combination of two or more. Of 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. Among these, acetylacetone metal complexes, salicylic acid metal complexes, alkylsalicylic acid metal complexes, dialkylsalicylic acid metal complexes, naphthoic acid metal complexes, and monoazo metal complexes are particularly preferably used.

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

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

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

Examples of the additives (ie, external additives) to be mixed with the toner particles include inorganic fine powder, inorganic fine powder having been subjected to surface treatment, and organic fine powder.

Examples of the inorganic fine powder include a fine powder of an inorganic oxide and a fine powder of a carbonate compound. As inorganic oxides, alumina, zinc oxide, tin oxide, titanium oxide, and multiple oxides (strontium titanate, barium titanate,
Calcium titanate, strontium zirconate and calcium zirconate). Examples of the carbonate compound include calcium carbonate and magnesium carbonate. Among these, a composite oxide of titanium oxide, particularly a fine powder of strontium titanate, exhibits an excellent effect.

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

Further, the BET specific surface area is 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, improve the fluidity of toner particles. 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) are preferable as an additive. It is preferable as a toner microcarrier.

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

If necessary, additives other than those described above may be mixed. Such additives include lubricating agents such as Teflon, polyvinylidene fluoride, metal salts of fatty acids; abrasives such as silicon carbide; fluidizing or anti-caking agents; fixing aids such as carbon black or low molecular weight polyethylene. Is mentioned. A wax-like substance such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, microcrystalline wax, carnauba wax and sasol wax is added to the toner of the present invention in an amount of 0.5 to 5 wt. % May be added.

In producing the toner, the above-mentioned toner constituent materials are sufficiently mixed by a mixer, then kneaded well using a heat kneader such as a hot roll kneader or an extruder, and the kneaded material is cooled and solidified. Pulverization, pulverization, classification of the pulverized material to obtain toner particles, and mixing of the toner particles and additives to obtain a toner are preferred. Another method is to obtain toner particles by dispersing a constituent material in a binder resin solution and then spray-drying the mixture; mixing a predetermined material with a monomer to form the binder resin to emulsify and suspend. There is a method for producing toner particles by a polymerization method in which a liquid is formed and then polymerized to obtain a toner. The toner particles according to the present invention may be microcapsule toner particles composed of a core material and a shell material.

[0047]

Hereinafter, the present invention will be described in detail with reference to specific examples. The present invention is not limited to only 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 with a Henschel mixer, the mixture is heated and melt-kneaded with a twin-screw extruder, and the cooled kneaded material is roughly crushed to about 100 μm to obtain a coarsely crushed material, and the coarsely crushed material is jet-crushed. A finely pulverized product was obtained by a pulverizer, 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 75 liter Henschel mixer, 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 adjusted. 1
The mixture was stirred and mixed at 800 rpm for 5 minutes to obtain a magnetic toner (A). The hydrophobic colloidal silica fine powder had a BET specific surface area of 200 m ² / g by a nitrogen adsorption method, and 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 materials, coarse particles, re-aggregates, etc. in the production process,
The average opening W is 112 μm and the average diameter d of the wire is 0.1 μm.
A sieve having a twill weave stainless steel netting of 100 mm and d / W of 8.93 × 10 ^-4 (120 meshes)
gyro shifter (perforated per Linear Inch) with a turning radius of 30 mm and a turning number of 230 r
pm), and the processing amount of the magnetic toner (A) is 5 kg.
/ M ² · min to obtain a magnetic toner (A-a).

Even after the operation for a total of 500 hours, the sieve net was not damaged, and no coarse powder, fused matter and reaggregated matter were mixed in the magnetic toner (Aa).

The magnetic toner (A-a) passed through the sieve is put into a Canon copier NP2020, and is put into a room temperature and normal humidity (temperature 23)
When the image was formed at a temperature of 60 ° C. and a humidity of 60% RH, no image loss such as fog and reversal fog was observed at an image density of 1.35.

The copier was left overnight in a high-temperature and high-humidity environment (temperature 32.5 ° C., humidity 85% RH), and then imaged under normal temperature and normal humidity environment. 1.31 concentration
However, on the tenth sheet, the image density was restored to 1.35.

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. The magnetic toner (A) is added and stirred and mixed at a rotation speed of a stirring blade of 1800 rpm for 5 minutes.
I got

The obtained magnetic toner (A) was subjected to an average opening W
Is 125 μm, the average diameter d of the wire is 0.087 mm,
A sieve having a flat-woven stainless steel mesh having a d / W of 6.96 × 10 ⁻⁴ (120 Mesh per Line)
The magnetic toner (A) was passed at a processing rate of 5 kg / m ² · min using a gyro shifter equipped with a magnetic ink (Ab). After a total of 50 hours of operation,
The sieve mesh was damaged by abrasion.

When the magnetic toner (Ab) was put in a Canon copier NP2020 and an image was formed at normal temperature and normal humidity, the image density was 1.30.

After the copying machine was left overnight in a high-temperature and high-humidity environment, images were formed in a normal-temperature and normal-humidity environment. The first sheet of the image had an image density of 1.15. Image density is 1.
20 and the image density finally recovered to 1.30 on the 50th sheet.

Comparative Example 2 A magnetic toner (A) that had not passed through a sieve had an average opening W of 1
11 μm, average wire diameter d is 0.070 mm, d /
Sieve with a plain weave stainless steel mesh of W = 6.31 × 10 ⁻⁴ (140 Mesh per Linea)
r Inch), the magnetic toner (A) was passed at a processing rate of 5 kg / m ² · min with a gyro shifter to obtain a magnetic toner (Ac). After a total of 30 hours of operation, the sieve mesh was damaged by abrasion.

The image density was 1.30 when the magnetic toner (Ac) was placed in a Canon copier NP2020 and an image was formed at normal temperature and normal humidity.

After leaving the copier overnight in a high-temperature, high-humidity environment, an image was formed in a normal-temperature, normal-humidity environment. Image density is 1.
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

The above-mentioned materials are uniformly mixed with a Henschel mixer, then heated and melt-kneaded with a twin-screw extruder, and the cooled kneaded material is roughly crushed to about 100 μm to obtain a coarsely pulverized material, and the coarsely pulverized material is jet-pulverized. A finely pulverized product was obtained by a pulverizer, 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 a BET specific surface area of 5 m ² /
g of cerium oxide fine powder (2 wt%) was added thereto, 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). From the obtained magnetic toner (B), in order to remove a fusion product, a loose substance coarse particle, a re-aggregate, etc. in the production process, the average opening W is 152 μm, the average diameter d of the wire is 0.13 mm, and the d / W is A sieve having a twill weave of 8.55 × 10 ^-4 stainless steel mesh (90 Mesh
gyro shifter equipped with a magnetic toner (B) of 5 kg / m.
^The mixture was passed for ² minutes to obtain a magnetic toner (Ba). Even after the operation for a total of 500 hours, the sieve net was not damaged, and the magnetic toner (Ba) did not contain any coarse powder, fused matter, or re-agglomerated matter.

When the magnetic toner (Ba) passed through the sieve was put into a Canon copier NP2020 and imaged at normal temperature and normal humidity, image defects such as fog and reversal fog were found at an image density of 1.30. I couldn't see it.

The copier was left overnight in a high-temperature and high-humidity environment (temperature 32.5 ° C., humidity 85% RH), and then imaged under normal temperature and normal humidity environment. Concentration 1.26
However, the image density recovered to 1.30 on the tenth sheet.

Comparative Example 3 A magnetic toner (B) not passed through a sieve was treated with an average opening W
Is 162 μm, the average diameter d of the wire is 0.120 mm,
A sieve having a plain weave stainless steel mesh having a d / W of 7.4 × 10 ⁻⁴ (90 Mesh per Linear)
A magnetic toner (Bb) was obtained by passing the magnetic toner (B) at a processing rate of 5 kg / m ² · min with a gyro shifter equipped with an Inch). After a total of 90 hours of operation, the sieve mesh was damaged by abrasion.

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

After leaving the copying machine overnight in a high-temperature and high-humidity environment, an image was formed in a normal-temperature and normal-humidity environment. Image density is 1.
The image density was finally restored to 1.24 on the 50th sheet.

Comparative Example 4 A magnetic toner (B) which had not passed through a sieve was subjected to an average opening W
Is 132 μm, the average diameter d of the wire is 0.150 mm,
A sieve having a twill stainless steel mesh with a d / W of 11.36 × 10 ^-4 (90 Mesh per Lin)
A magnetic toner (B-c) was obtained by passing the magnetic toner (B) at a processing rate of 5 kg / m ² · min. After a total of 110 hours of operation, the sieve mesh was damaged by abrasion.

When the magnetic toner (Bc) was placed in a Canon copier NP2020 and an image was formed at normal temperature and normal humidity, the image density was 1.20.

After the copying machine was left overnight in a high-temperature and high-humidity environment, an image was formed in a normal-temperature and normal-humidity environment. Image density is 1.2
It finally recovered to 0.

Example 3 99.7 wt% of the magnetic toner particles (B) prepared in Example 2
% And 0.3 wt% of hydrophobic colloidal silica fine powder were stirred and mixed with a Henschel mixer to obtain a magnetic toner (C). The obtained magnetic toner (C) was treated with an average opening W of 1
34 μm, average wire diameter d is 0.120 mm, d / W
Having a 8.96 × 10 ⁻⁴ twill weave stainless steel mesh (100 Mesh per Linea)
rInch), the magnetic toner (C) was passed at a processing rate of 5 kg / m ² · min using a gyro shifter to obtain a magnetic toner (Ca). Even after the operation for a total of 500 hours, the sieve net was not damaged, and the magnetic toner (Ca) did not contain any coarse powder, fused matter, or re-agglomerated matter.

When an image was formed on the magnetic toner (Ca) using a Canon copier NP2020, the image density was 1.
In No. 30, no image loss such as fog and reverse fog was observed.

The copier was left overnight in a high-temperature and high-humidity environment (temperature 32.5 ° C., humidity 85% RH) and then imaged under normal temperature and normal humidity. When the concentration is 1.2
However, the image density was restored to 1.30 on the tenth sheet.

Comparative Example 5 The magnetic toner C prepared in Example 3 was prepared by adding an average opening W of 1
40 μm, average wire diameter d is 0.114 mm, d / W
Has a mesh of 8.14 × 10 ⁻⁴ plain-woven stainless steel mesh (100 Mesh per Linear).
A magnetic toner (Cb) was obtained by passing the magnetic toner (C) at a processing rate of 5 kg / m ² · min with a gyro shifter equipped with an Inch).

When the magnetic toner (Cb) was placed in a Canon NP2020 copying machine and an image was formed at normal temperature and normal humidity, the image density was 1.27.

After the copying machine was left overnight in a high-temperature and high-humidity environment, images were formed in a normal-temperature and normal-humidity environment. Image density is 1.2
Finally recovered to 7.

[0079]

[Table 1]

[0080]

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

[Brief description of the drawings]

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

FIG. 2 is an explanatory view of a plain weave.

FIG. 3 shows a general flow of manufacturing a toner.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masayoshi Uchiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-2-136864 (JP, A) JP-A-1 -202761 (JP, A) JP-A-2-167559 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/08

Claims (3)

(57) [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 [where d is the average of the wires constituting the net used for the sieve A toner particle size, and W represents the size of the sieve mesh]. 2. The method according to claim 1, wherein the toner particles are formed from magnetic toner particles, and the external additive is formed from 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 a toner according to claim 2.