JP2003295509A - Magnetic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide magnetic toner which enables high picture density while suppressing the quantity of external addition of inorganic fine particles as low as possible in order to realize a durable cartridge or drum unit by suppressing the drum wear. <P>SOLUTION: The magnetic toner comprises at least a binder resin and a magnet. The toner has the weight average diameter of 4-12 μm and is externally added with silica fine particles of 0-1.0% which are ≥175 m<SP>2</SP>/g and are treated with a silane coupling agent and silicone oil on the surface of the toner. Further, when the amount of external addition of the silica fine particles is X wt.% and the degree of aggregation at X wt.% external addition is Y%, the following expression is given between X and Y: Y≤80exp(-1.6X) (Exp. 1). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic charge image or a magnetic toner for forming a toner image in a toner jet type image forming method.

[0002]

2. Description of the Related Art Conventionally, in one-component development using a magnetic toner, in order to improve characteristics such as toner transfer efficiency and obtain a high density image, inorganic fine particles typified by silica are used as a fluidity imparting agent. External attachment was essential.

However, since these inorganic fine particles have high hardness, a so-called organic photoreceptor (organic photoreceptor) prepared by coating one or more layers of a photosensitive drum, particularly an organic resin, is used.
There has been a problem that development occurs that the surface of the OPC is scraped off when it comes into contact with the photo conductor (OPC). This scraping is a phenomenon that is more prominent particularly when the toner comes into contact with the OPC and is rubbed there, as represented by the development and cleaning processes. When the number of scrapes of OPC increases due to the durability test or long-term use, the electric field strength increases due to the decrease in the film thickness of OPC, so that the injection from the support side is promoted, the charging ability decreases, and so-called fogging in the reversal development system occurs. There was a problem that happened.

In order to suppress the abrasion of the drum, for example, JP-A-10-326028 discloses a method of using alumina particles, and JP-A-11-153886 and 2000-75555 disclose a binder resin for toner. The method of using a soft resin is introduced respectively.

However, these inventions are not the means for reducing or eliminating the abrasion of the drum most effectively because they are not means for reducing the amount of the inorganic fine particles to be added externally or not. In addition, in a general magnetic toner, the amount of externally added inorganic fine particles is simply reduced,
Alternatively, if the method of not adding externally is adopted, the toner original performance such as the toner density is lowered because the toner cohesion is too high and the transfer efficiency is lowered, resulting in a problem. For the above reason, a toner that has both essential prevention of drum deterioration and high density has not been realized.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to externally add inorganic fine particles in order to realize a durable cartridge or drum unit without causing or minimizing the above-described drum scraping. An object of the present invention is to provide a magnetic toner that achieves high density while suppressing the amount as much as possible.

[0007]

The above objects can be achieved by the present invention described below.

That is, the present invention is a magnetic toner containing at least a binder resin and a magnetic substance, and has a weight average diameter of 4 to 1.
The toner has a particle size of 2 μm, and silica fine particles of 175 m ² / g or more, which are treated with a silane coupling agent and silicone oil, are externally added to the toner surface in an amount of 0 to 1.0%, and the silica is When the external addition amount of the fine particles is X mass% and the cohesion degree at the time of external addition of X mass% is Y%, the following formula Y ≦ 80exp (−1.6X) (Formula 1) holds between X and Y. The present invention relates to a magnetic toner.

Further, the present invention relates to a magnetic toner characterized in that the following formulas are satisfied in X and Y mentioned above. Y ≦ 75exp (-1.8X) (Formula 2)

The present invention also provides the following formulas 1 and 2:
X, that is, the amount of silica fine particles added externally is 0 to 0.5% by mass.
The present invention relates to a magnetic toner characterized by the following.

The present invention also provides the following equations 1 and 2:
X, that is, the amount of silica fine particles added externally is 0 to 0.3% by mass.
The present invention relates to a magnetic toner characterized by the following.

Further, the present invention relates to a magnetic toner satisfying the above expressions 1 and 2 and having an average circularity of 0.960 or more.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The inventors of the present invention have made earnest studies on the relationship between the abrasion of the photosensitive drum and the amount of the inorganic fine particles externally added to the magnetic toner. Specifically, the weight average particle diameter of the magnetic toner is 4 to 12 μm, and the fine particles have a specific surface area of 175.
In the case of silica fine particles of m ² / g or more and treated with a silane coupling agent and silicone oil, if the content is 0 to 1.0% or less, abrasion of the photosensitive drum is minimized even after long-term use. It was found that the fogging that is thought to be caused by the scraping of the drum is suppressed.

However, the fact that the amount of the silica fine particles added externally is small means that the fluidity of the toner is lowered. When the fluidity of the toner is low, the transfer efficiency is low and the image density is lowered. It causes problems such as occurrence.

Therefore, as a result of our earnest studies, as a toner composition showing a high concentration even if the external addition amount of the silica fine particles is suppressed to 0 to 1.0% by mass or less in order to minimize drum abrasion, The external addition amount of the silica fine particles is X
Mass%, X mass% A toner satisfying the following formula Y ≦ 80exp (−1.6X), more preferably Y ≦ 75exp (−1.8X), where Y% is the aggregation degree of the toner when externally added. It has been found that a toner capable of achieving a sufficient image density can be achieved even when the external addition amount is 0 to 1.0% by mass or less when the above condition is satisfied.

As a result, by using the toner of the present invention, the abrasion of the drum can be reduced, and the life of the cartridge and the drum can be extended.

In FIG. 1, Y = 80exp (-1.6X) [Y
= 80e ^−1.6X ], and the meaning of Y ≦ 80exp (−1.6X), which is an essential condition of the present invention, will be described below. Satisfying Y ≦ 80exp (−1.6X) means that the aggregation degree is below the profile of the graph in FIG. As a result of our study, the cohesion degree was Y = 80exp (-
It has been found that a toner having a particle size of less than 1.6X) exhibits a sufficient image density even when the external addition amount of silica is 1.0% by mass or less, and as a result, the reduction of drum abrasion can be achieved. The points A to F in the figure will be described below.

In A and B in the figure, since both of the external addition amounts are low, the drum abrasion is small and the durability of the cartridge or the drum unit is high, but in B, a good image is obtained, but in A, an image with sufficient density is obtained. It became clear that it could not be obtained. That is, A has a high aggregation degree of 90% by mass when externally added at 0.1% by mass, and the image density becomes low due to reasons such as a decrease in transfer efficiency, so that a substantially good electrophotographic image cannot be obtained. No, but B has a relatively low degree of aggregation,
It is considered that the image density was such that there was no problem in practical use even when the external addition amount was as low as 0.1% by mass.

As described above, a relatively small external additive amount region (0.
The present inventors believe that the fact that a low aggregation degree is exhibited even at 5% by mass or less) is achieved by the state where the external addition amount is 0, that is, the so-called non-external addition toner has a low aggregation degree. Specifically, the cohesion degree of the toner not yet added is expressed as X = Y in formula 1: Y ≦ 80exp (−1.6X), which is an essential condition of the present invention.
It is essential for the present invention that the value of Y when 0, that is, 80% by mass or less, more preferably the value of Y when X = 0 in Formula 2 described in claim 2, that is, 75% by mass or less. It is a necessary condition that satisfies the condition Y ≦ 80exp (−1.6X).

The point C in the figure will be described. In the study by the present inventors, the reason is not clear, but C
In the case of a toner such that Y ≧ 80exp (−1.6X) at a relatively high external additive amount (0.5% by mass or more and 1.0% by mass or less) as shown in FIG. Although no deterioration in image quality due to such drum abrasion was observed, a decrease in image density was observed. The reason for this is as follows.

First, a relatively high external additive amount (0.
The reason why the degree of aggregation is high even in the range of 5% by mass or more and 1.0% by mass or less) was considered in relation to the surface roughness of the toner (see FIG. 2). That is, when the same amount of inorganic fine particles is externally added to a toner having a large number of surface irregularities and a toner having a relatively smooth surface, as shown in FIG.
It is expected that the inorganic fine particles will enter the recesses, and the amount of the inorganic fine particles substantially working shown in black in the figure will decrease. That is, it is presumed that the initial degree of aggregation is low because the substantial amount of silica is small. The fact that the toner deteriorates due to durability is presumed to be equivalent to the fact that silica is embedded or liberated and the amount of silica is reduced, but at that time, the toner at point C initially deteriorates. A state where the degree of cohesion is high as represented by A later, that is, Y
It becomes ≧ 80 exp (−1.6 ×), and as a result, it is presumed that the image quality such as a decrease in image density is affected.

From the above, the meaning of the formula 1 shows a relatively low degree of aggregation even in a region where the amount of external addition is relatively small (0 to 0.5% by mass or less), that is, the aggregation of unexternally added toner is low. And a low degree of aggregation in a region where the amount of external addition is relatively large (0.5% by mass or more and 1.0% by mass or less),
That is, it can be said that it is a formula that comprehensively shows that the toner has few surface irregularities and the external additive works effectively.

The method of measuring the degree of aggregation in the present invention will be described below.

Cohesion Degree Measuring Method In the present invention, the cohesion degree was used as a means for measuring the flow characteristics of the sample. The larger the value of the degree of aggregation, the worse the fluidity of the sample.

As the measuring device, a powder tester (manufactured by Hosokawa Micron Co.) having a digital vibrometer (Digivibro MODEL 1332) is used.

As a measuring method, sieves of 250 mesh, 150 mesh, and 75 mesh are placed on the vibrating table in the order of narrow openings, that is, in order of the sieve of 250 mesh, 150 mesh, and 75 mesh so that the 75 mesh sieve is at the top. I set them on top of each other.

5 g of a sample weighed accurately was added onto the set 75 mesh sieve, the displacement value of the digital vibrometer was adjusted to 0.6 mm (peak-to-peak), and vibration was applied for 15 seconds. It was Then, the mass of the sample remaining on each sieve was measured to obtain the cohesion degree according to the following formula.

[0028]

[Equation 1]

In the present invention, the weight average diameter is 4 to 12 μm.
The external addition amount of silica fine particles having a specific surface area of 175 m ² / g or more to the magnetic toner of m is 0 to 1.0% by mass or less,
When the content is more preferably 0 to 0.5% by mass or less, and further preferably 0.3% by mass or less, fog due to abrasion of the photoconductor is reduced. If the amount of external additive is more than this amount (E, F in FIG. 1), the amount of external additive added is large, so that the damage caused by the liberated external additive to the photoreceptor becomes large.

Here, a method for determining the externally added amount of the inorganic fine particles of the present invention will be described.

Measurement of Externally Added Amount of Silica The externally added amount of silica fine particles of the toner in the present invention is determined by dissolving the silica fine particles on the toner surface in an alkaline aqueous solution and measuring the silica concentration in the aqueous solution by plasma emission spectrometry (ICP-
AES) to calculate the molecular weight of silica per unit gram of toner, and then determine SiO ₂ mass% with the silica fine particles as SiO ₂ .

Specifically, 1 g of Na is added to 25 ml of pure water.
About 1 g of a sample is weighed and put into an aqueous solution in which OH is dissolved, and shaken for 6 hours at room temperature to completely dissolve the silica fine particles on the toner surface. Next, the Si concentration in the aqueous solution in which silica is dissolved is determined by plasma emission spectrometry using SP4000 type manufactured by Seiko Denshi Kogyo. This value is now X
Assuming that it is mass%, the amount of silica added externally, that is, the mass% of SiO ₂ is calculated by the following formula.

[0033]

[Equation 2]

Further, in the formulas 1 and 2 which are the characteristics of the toner of the present invention, the specific surface area of the externally added inorganic fine particles is 175 m ^2.
/ G or more and the case where it is treated with a silane coupling agent and silicone oil.

The silane coupling agent used in the present invention is hexamethyldisilazane or a general formula RmSiYn R: an alkoxy group or a chlorine atom m: an integer of 1 to 3 Y: an alkyl group, a vinyl group, a glycidoxy group, a methacryl group. A hydrocarbon group containing n: an integer of 1 to 3, for example, typically dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyl. Triethoxysilane, γ-
Methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane, dimethylvinylchlorosilane and the like can be mentioned.

The treatment of the silica fine powder with a silane coupling agent is carried out by a dry method in which the vaporized silane coupling agent is reacted with a fine powder made into a cloud by stirring, or by dispersing the fine powder in a solvent. The treatment can be carried out by any of the wet methods in which the ring agent is dropped and reacted.

The silicone oil used in the present invention is generally represented by the following formula.

[0038]

[Chemical 1]

Examples thereof include dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil.

The silicone oil is preferably 25
A viscosity of about 50 to 1000 mm ² / s is used. Silicone oil having a too low molecular weight may generate volatile components due to heat treatment or the like. If the molecular weight is too high, the viscosity becomes too high and the treatment becomes difficult.
Further, the silicone oil described in JP-A No. 9-166885 and its treatment method can also be preferably used.

A known technique can be used as the method for treating the silicone oil. For example, silica fine powder and silicone oil may be directly mixed by using a mixer such as a Henschel mixer, or a method of spraying silicone oil on the base silica may be used. After the silicone oil is dissolved or dispersed in a suitable solvent, the silica fine powder of the base is added and mixed, and the solvent may be removed for the treatment.

The toner of the present invention has a specific surface area of 175.
The external addition amount of silica fine particles of m ² / g or more is specified. Generally, as the particle size of the external additive increases, that is, the specific surface area decreases, the ability to impart fluidity to the toner decreases. According to the study by the present inventors, a specific surface area of 175 m ² / g
When the same amount of an external additive of less than 175 m ² / g is externally added to the toner satisfying the formula 1 or the formula 2 when the above silica is used, the aggregation degree becomes high. In some cases, the condition 2 may not be satisfied. Therefore, the toner form defined by the formula 1 and the formula 2 which is the characteristic of the toner in the present invention is limited to the case where the specific surface area of the silica fine particles is 175 m ² / g or more.

Further, as shown in FIG. 2, the existence density of the external additive on the toner surface is an important point in producing the effect of the present invention. Although the particle size of the toner and the particle size distribution of the toner are greatly related to the existence state of the external additive, according to the studies by the present inventors, when the weight average particle size is 4 to 12 μm, the formula 1 and the formula 2 are It became clear that it holds.

The method for measuring the particle size and the method for measuring the specific surface area in the present invention are shown below.

Method for Measuring Toner Particle Size The toner of the present invention has a weight average particle size of Coulter Multisizer (manufactured by Beckman Coulter, Inc.) and ISOTON for the electrolytic solution.
R-II (1% NaCl aqueous solution, manufactured by Coulter Scientific Japan Co., Ltd.) was used for the measurement by the following method. As a measuring method, the electrolytic aqueous solution 100 is used.
0.1 ~ 5ml of surfactant as a dispersant in ~ 150ml
ml, and further add about 2 to 20 mg of the powder sample to be measured. Use an ultrasonic disperser to disperse the electrolyte in which the sample is suspended to approximately 1
After the dispersion treatment for 3 minutes, the volume and the number are measured by the measuring device to calculate the weight average particle diameter. When the weight average particle diameter is 6 μm or more, the particle diameter of 2 to 60 μm is measured using an aperture of 100 μm, and the weight average particle diameter is 6 to
In the case of 2.5 μm, the particle size of 1 to 30 μm is measured using an aperture of 50 μm, and the weight average particle size is 2.5 μm.
If less than 0.6 with a 30 μm aperture
Measure ~ 18 μm particles.

[0046] of the measurement method specific surface area of the specific surface area measurement: The measurement of the specific surface area, ASTM method D30
It is performed in accordance with the BET formula in 37-78. That is, a mixed gas of N ₂ and He is flown through carbon black to adsorb N ₂ and the amount thereof is detected by a thermal conductivity cell, and the specific surface area of the sample is calculated from the N ₂ adsorption amount. 1) The sample is dried at 105 ° C. for 1 hour, then precisely weighed 0.1 to 1 g, put in a U-shaped tube, and attached to the flow path. 2) Change the N ₂ / He mixture ratio by the flow rate controller and set it to a predetermined P / P 0. 3) After opening the cock to introduce the adsorbed gas into the sample layer, U
Soak-tube in liquid N ₂ adsorbing N _2. 4) After reaching the adsorption equilibrium, removing liquid N ₂ for 30 seconds,
After exposing to air, the U-tube is immersed in water at room temperature to desorb N ₂ . 5) Draw the desorption curve on the recorder and measure the area. 6) Prior to these operations, a calibration curve prepared by introducing a known amount of N ₂ was used to determine the N ₂ adsorption amount at a predetermined P / P0 from the area obtained for the above sample.

The surface area is obtained by applying the following equation. P / v (P0-P) = 1 / vmC + (C-1) / vmC
× P / P0 P0: Saturated vapor pressure of adsorbate at measurement temperature P: Pressure at adsorption equilibrium νm: Adsorption amount at adsorption equilibrium ν: Adsorbed gas volume C: Constants P / P0 and P / ν (P0-P ) Is a straight line,
Νm is calculated from the gradient and the intercept. If νm is obtained, the specific surface area S is calculated by the following equation. S = A × νm × N / W where: S: specific surface area A: cross-sectional area of adsorbed molecule N: Avogadro's number W: sample amount

Further, the study by the present inventors has revealed that when the average circularity is 0.960 or more, the requirement of the toner of the present invention described in claim 1 is easily satisfied.

That is, the toner having an average circularity of 0.960 or more has a smaller surface area than the toner having an average circularity of less than 0.960.
In other words, from the viewpoint of FIG. 2, comparing the one with a large average circularity and the one with a small average circularity means that the one with a larger average circularity has a smaller surface area, that is, there is substantially more effective silica. There is. Therefore, it is considered more preferable that the average circularity is 0.960 or more in order to satisfy Expression 1. The method for measuring the average circularity of the present invention is shown below.

Method of Measuring Average Circularity In the present invention, the average circularity of the toner can be obtained by measuring with a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics. As a specific measuring method, water 1 in which impure solids and the like are previously removed in a container
0.1 to 0.5 m of a surfactant, preferably an alkylbenzene sulfonate, as a dispersant in 0 to 150 ml.
1, and 0.1 to 0.5 g of a measurement sample is further added. The suspension in which the sample is dispersed is subjected to a dispersion treatment for 1 to 3 minutes with an ultrasonic disperser, the dispersion concentration is set to 3000 to 10000 / μl, and the average circularity is measured by the above apparatus.

Next, the method for producing the magnetic toner of the present invention will be described.

The method for producing the magnetic toner of the present invention includes:
Binder resin, magnetic material, other colorants, after thoroughly mixing the additives with a mixer, heating roll, kneader, using a heat kneader such as an extruder, after kneading, and then solidified by cooling, It may be a so-called pulverization method of pulverizing and classifying, or a method of atomizing a molten mixture into the air using a disk or a multi-fluid nozzle described in Japanese Patent Publication No. 56-13945 to obtain toner particles, Japanese Patent Publication 36-
No. 10,231, JP-A-59-53856, and JP-A-59-61842, the method of producing toner particles using the suspension polymerization method and the monomer are soluble. The obtained polymer is a method of producing toner particles by a dispersion polymerization method using an insoluble hydrophilic organic solvent, or a method of producing toner particles by an emulsion polymerization method in which polymerization is performed in the presence of a water-soluble polymerization initiator. Etc. may be used. Further, in addition to any one of the above-mentioned toner production methods, a method of giving a mechanical impact or a method of heating in a hot air flow, and further, JP-A No.
000-47424, JP-A 2000-10548.
6, JP 2001-27824 A, JP 9
It is also possible to perform the sphering treatment by a wet method as described in JP-A-34166.

In particular, when the crushing method is used, the method disclosed in Japanese Patent Laid-Open No.
It is more preferable to perform the spheroidizing treatment as described above, as described in JP-A 1-216377, and it is more preferable to rotate the rotor to give a mechanical impact force.

As the binder resin which can be used when the toner is prepared by the pulverization method, for example, polystyrene,
Styrene-substituted homopolymers such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-acrylic acid esters Copolymer, styrene-methacrylic acid copolymer, styrene-α-chloromethylmethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer, polyvinyl chloride, enol resin, natural modified phenolic resin, natural modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, Examples include xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, and petroleum-based resin. Crosslinked styrenic copolymers and crosslinked polyester resins are also preferred binder resins.

Examples of the comonomer for the styrene monomer of the styrene type copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Didecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof; a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and a substituted product thereof; for example, vinyl chloride, vinyl acetate, Vinyl esters such as vinyl benzoate; ethylene-based olefins such as ethylene, propylene, butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone; Ether, vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether; vinyl monomers such as may be used singly or two or more kinds.

The styrene-based polymer or styrene-based copolymer may be crosslinked or a mixed resin thereof.

When the suspension polymerization method is used, for example, a monomer composition comprising a polymerizable monomer, a colorant, a polymerization initiator and other additives is prepared and a dispersant is contained. In the aqueous medium to be used, the monomer composition is dispersed by, for example, a homogenizer or a homomixer, and granulated. After that, stirring is performed to such an extent that particles are prevented from settling, and the polymerization reaction proceeds. The polymerization temperature is preferably 30 to 90 ° C., more preferably 40 ° C. or higher and 80 ° C. or lower for polymerization. The temperature may be raised in the latter half of the polymerization reaction, and in order to remove unreacted polymerizable monomers, by-products, etc.,
The aqueous medium may be partially distilled off in the latter half of the reaction and / or after the completion of the reaction. After the reaction is completed, the produced toner particles are collected by washing and filtration and dried.

Examples of the polymerizable monomer used when obtaining the toner particles by the polymerization method include styrene, o-methylstyrene, m-methylstyrene, p-methoxystyrene, p-ethylstyrene and pt-t-. Styrene monomers such as butyl styrene, acrylic acid, methyl acrylate,
Ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, Methacrylic acid, methyl methacrylate, ethyl methacrylate, methacrylic acid-n
-Propyl, -n-butyl methacrylate, isobutyl methacrylate, -n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, diaminomethyl methacrylate, dimethylaminoethyl methacrylate. , Benzyl methacrylate, crotonic acid, isocrotonic acid, acid phosphoxyethyl methacrylate, acid phosphooxypropyl methacrylate, acroylmorpholine, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. Acrylic acid type monomer, methyl vinyl ether, ethyl vinyl ether,
Propyl vinyl ether, n-butyl ether, isobutyl ether, β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether, p
Vinyl chloride monomers such as chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether, p-methoxyphenyl vinyl ether, butadiene, etc., itaconic acid, maleic acid, fumaric acid, monobutyl itaconic acid, monobutyl maleate, etc. Dibasic acid-based monomer, 2-vinylpyridine, 3-vinylpyridine,
Examples thereof include heterocyclic monomers such as 4-vinylpyridine and N-vinylimidazole.

These monomers may be used alone or in combination of two or more kinds, and the polymer composition which is arbitrarily combined can be selected so as to obtain preferable characteristics. Further, a crosslinking agent may be used in the monomer composition, if necessary.

The resin composition according to the present invention has a glass transition temperature (Tg) of 45 to 75 ° C., preferably 50 to 70 ° C. from the viewpoint of storability. Are likely to deteriorate, and offset is likely to occur during fixing. Further, if Tg exceeds 75 ° C., the fixability tends to decrease.

As the magnetic material used in the present invention, magnetic iron oxide such as magnetite, maghemite and ferrite is used, and it is preferable that the magnetic iron oxide contains a non-ferrous element on its surface or inside.

The magnetic substance used in the present invention is magnetic iron oxide containing different elements, such as magnetite, maghemite and ferrite, and a mixture thereof.

Among them, lithium, beryllium, boron, magnesium, aluminum, silicon, phosphorus, germanium, titanium, zirconium, tin, lead, zinc, calcium, barium, scandium, vanadium, chromium, manganese, cobalt, copper, nickel, gallium, A magnetic iron oxide containing at least one element selected from cadmium, indium, silver, palladium, gold, netium, ruthenium, rhodium and bismuth is preferable. In particular, lithium, beryllium, boron, magnesium, aluminum, silicon, phosphorus, germanium, zirconium, tin, and a transition metal element of the fourth period are preferable elements. These elements may be incorporated into the iron oxide crystal lattice, may be incorporated into iron oxide as an oxide, or may be present on the surface as an oxide or a hydroxide. Further, it is a preferable form to be contained as an oxide.

The amount of the magnetic substance contained in the toner is 20 to 200 parts by mass with respect to 100 parts by mass of the resin component, particularly preferably 40 to 100 parts by mass of the resin component.
More preferably 150 parts by mass.

Other colorants that can be used in the toner include any suitable pigment or dye. For example, pigments such as carbon black, aniline black, acetylene black, naphthol yellow, hansai yellow, rhodamine lake, anizarin lake, red iron oxide,
Examples include phthalocyanine blue and indanthrene blue. These can be used in an amount sufficient to maintain the optical density of the fixed image. Resin 10 if used
0.1 to 20 parts by weight, preferably 1 to 0 parts by weight
Preference is given to using 10 parts by weight of pigment. Dyes can be used for the same purpose. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, and it is preferable to use 0.1 to 20 parts by mass, preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the resin.

If desired, a wax may be added to the toner of the present invention. The wax used in the toner of the present invention includes the following. For example, low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymers, polyolefin wax, microcrystalline wax, paraffin wax, Fischer Trop wax, and other aliphatic hydrocarbon waxes; oxide polyethylene wax and other aliphatic hydrocarbon wax oxides. Or block copolymers thereof; vegetable waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax; animal waxes such as beeswax, lanolin, whale wax; mineral waxes such as ozokerite, ceresin, petrolactam. Waxes containing fatty acid esters such as montanic acid ester wax and castor wax as a main component; deoxidized fatty acid esters such as deoxidized carnauba wax Furthermore, palmitic acid, stearic acid, montanic acid,
Or saturated straight chain fatty acids such as alkyl carboxylic acids having a longer chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinaric acid; stearyl alcohol, melysyl alcohol, or a longer chain alkyl group. Saturated alcohols such as long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; aliphatic amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylenebisstearic acid amide, ethylenebislauric acid amide, hexamethylenebis Saturated fatty acid bisamides such as stearic acid amides; Unsaturation such as ethrene bisoleic acid amides, hexametholene bisoleic acid amides, N, N'-dioleyl adivic acid amides, N, N'-dioleyl sebacic acid amides Fatty acid amides; -Aromatic bisamides such as xylene bisstearic acid amide, N, N'-disrealylisophthalic acid amide; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally called metal soap Existing wax); wax grafted with aliphatic hydrocarbon wax using vinyl monomer such as styrene and acrylic acid; partial ester compound of fatty acid and polyhydric alcohol such as behenic acid monoglyceride; hydrogenation of vegetable oil A methyl ester compound having a hydroxyl group can be mentioned. As the wax preferably used, a polyolefin obtained by radically polymerizing an olefin under high pressure; a polyolefin obtained by purifying a low molecular by-product obtained at the time of polymerizing a high molecular weight polyolefin; Polyolefin; Polyolefin polymerized by using radiant heat, electromagnetic waves or light; Low molecular weight polyolefin obtained by syntactically pyrolyzing polyolefin; Paraffin wax; Microcrystalline wax, Fischer-Tropsch wax; Zindole method, Hydrochol method, Arge method Synthetic hydrocarbon wax synthesized by, for example, a synthetic wax having a compound having 1 carbon atom as a monomer, a hydrocarbon wax having a hydrogen group or a functional group such as a carboxyl group, a hydrocarbon wax and a functional group A mixture of wax; styrene these waxes as a matrix, maleic acid ester, acrylate, methacrylate, waxes of such vinyl monomers with maleic anhydride graft modified.

Further, these waxes are pressed by a sweating method,
Sharpened molecular weight distribution using solvent method, recrystallization method, vacuum distillation method, supercritical gas extraction method or fused liquid crystal method, low molecular weight solid fatty acid, low molecular weight solid alcohol, low molecular weight solid compound, and other impurities Those from which is removed are also preferably used.

The wax used in the present invention has a melting point of 65 to 1 in order to balance the fixability and the offset resistance.
The temperature is preferably 60 ° C, more preferably 65 to 130 ° C, and particularly preferably 70 ° C to 120 ° C. If it is less than 65 ° C, the blocking resistance is lowered, and if it exceeds 160 ° C, the offset resistance effect is difficult to be exhibited.

In the toner of the present invention, the total content of these waxes is 0.1% with respect to 100 parts by mass of the binder resin.
It is effective to use 2 to 20 parts by mass, preferably 0.5 to 10 parts by mass. In addition, a plurality of waxes may be used in combination as long as they do not have an adverse effect.

In the present invention, the melting point of the wax is DS
The melting point of the wax is defined as the peak top of the maximum endothermic peak of the wax measured in C.

In the present invention, in the DSC measurement of a wax or a toner by a differential scanning calorimeter, it is preferable to measure with a high-precision differential scanning calorimeter of internal heat type input compensation method, for example, DSC-7 manufactured by Perkin Elmer. Is available.

The measurement method is according to ASTM D3418-82. The DSC curve used in the present invention was heated once and the previous history was taken, and then the temperature was measured at 10 ° C./min. ，
After the temperature is lowered in the range of 0 to 200 ° C., the DSC curve measured when the temperature is raised is used.

The toner of the present invention has a specific surface area of 175 m ² /
The toner is externally added with 0 to 1.0% by mass or less of silica fine particles of g or more. The silica fine particles are mainly for the purpose of imparting fluidity.
It is also possible to use resin fine particles or inorganic fine particles that serve to impart conductivity, prevent caking, act as a lubricant, an abrasive, and the like.

Lubricants such as, for example, polyfluorinated ethylene, zinc stearate and polyvinylidene fluoride, among which polyvinylidene fluoride is preferred. Alternatively, among polishing agents such as cerium oxide, silicon carbide and strontium titanate, strontium titanate is preferable. Alternatively, a small amount of a caking agent, for example, a conductivity imparting agent such as carbon black, zinc oxide, antimony oxide or tin oxide, or white and black fine particles having opposite polarities can be used as a developing property improver. The amount of the above-mentioned auxiliary agent mixed with the magnetic toner is preferably 3 parts by mass or less (preferably 0.5 parts by mass or less) with respect to 100 parts by mass of the magnetic toner. In addition, JP-A-10
The resin fine particles and metal oxide particles described in JP-A-3179 can also be preferably used.

In the magnetic toner of the present invention, a charge control agent is blended with toner particles (internal addition) or mixed with toner particles (external addition).
It can also be used. The charge control agent makes it possible to control the optimum charge amount according to the developing system, and particularly in the present invention, the balance between the particle size distribution and the charge amount can be further stabilized.

The following substances control the toner to be negatively charged. For example, organic metal complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, there are the following substances for controlling the positive charge property. Modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and onium such as phosphonium salts which are analogs thereof. Salts and lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, and ferricyanide (Russian compounds, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyltin volley. Diorgano tin borate such like; can be used in combination singly or two or more kinds.

The above charge control agents are preferably used in the form of fine particles, and in this case, the volume average particle diameter of these charge control agents is preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the toner, it is preferable to use 0.1 to 20 parts by mass, particularly 0.2 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

[0079]

Example (Toner Production Example 1) Styrene-butyl acrylate maleic acid monoethyl ester copolymer (weight average molecular weight 180,000, number average molecular weight 12,000, Tg 65 ° C.) 97 parts by mass Magnetic iron oxide [ Number average particle diameter 0.18 μm; Hc 9.63 kA / m (121 oersted) at magnetic field 795.8 kA / m (10 k oersted); σs 83 Am ² / kg; σr 11 Am ² / kg] 85 parts by mass propylene wax (melting point 140 ° C.) ) 3 parts by mass of azo iron complex compound 2.5 parts by mass The above formulation is sufficiently premixed by a Henschel mixer, melt-kneaded at a temperature of 140 ° C by a twin-screw extrusion kneader, and cooled to a hammer mill. It was roughly crushed to about 1 to 2 mm.

This was pulverized using a mechanical pulverizer whose schematic diagram is shown in FIG. Here, FIG. 4 is a schematic sectional view taken along the line DD ′ of FIG. 3, and FIG. 5 is a perspective view of the rotor 314 shown in FIG. In the mechanical pulverizer whose schematic diagram is shown in FIG. 3, the coarsely pulverized material is introduced from the powder inlet 311 and is a rotor 314 that is a rotor attached to the central rotating shaft 312.
And the rotor 314 while maintaining a minute gap from the rotor surface.
Is introduced into an annular space composed of a stator 310 arranged around the. The coarsely pulverized material passes through the space formed on the surface of the rotor 314 having a large number of grooves formed on the surface that rotates at high speed and the space formed on the inner wall of the stator 310 having a large number of grooves formed on the surface of the rotor 314. A mechanical impact force is given by the impact generated between the child 314 and the stator, a large number of ultra-high-speed turbulences generated behind this, and the high-frequency pressure vibration generated thereby, and the particles are crushed.

The finely pulverized powder obtained was classified using a multi-division classifier utilizing the Coanda effect to obtain a toner. The average particle size of the obtained toner was 7.10 μm.

(Production Example 2 of Toner) 150 g of the toner prepared in Production Example 1 of toner was weighed and introduced into a hybridization system (NHS-1 type) manufactured by Nara Machinery Co., Ltd. At that time, the processing conditions were as follows: rotation speed: 7200 rpm,
Processing time: 3 min, processing temperature: 52 ° C. After the above operation was completed, the obtained toner was again introduced into the above system, and the above operation was repeated 4 times under the same conditions to obtain a toner.

The non-externally added toner thus obtained had a weight average particle diameter of 7.09 μm.

[Example 1] A toner was manufactured in the manufacturing example 2 of toner.
Specific surface area of 200 m with respect to 100 parts by mass of toner ²/ G
Untreated silica (trade name of Nippon Aerosil Co., Ltd .; # 2
00) silane coupling treatment and silicone oil
Mixed 1.0 parts by mass of hydrophobic silica fine powder
And mix it thoroughly with a Henschel mixer.
The toner was subjected to an additive treatment and designated as Toner 1.

The average circularity of the obtained toner 1 is 0.98.
1, the cohesion degree Y was 12.1%. Further, when the external addition amount of this toner was measured by the above-mentioned method, the SiO ₂ concentration was 0.97%. Then, applying this value to Equation 1 and Equation 2, the external addition amount of this toner and the cohesion degree Y
Is 80exp (-1.6X)> Y, and 75e
xp (-1.8X)> Y.

Using this toner as a one-component developer, a GP215 developing device manufactured by Canon Inc. was put into a developing device modified to have a toner amount of about 500 g, and an A4 size original was randomly printed with a solid circle of 1 cm diameter having a diameter of 5 cm. A chart in which dots were lined up was copied, the image density of a perfect circle portion was measured using a Macbeth reflection densitometer (manufactured by Macbeth Co., Ltd.), and the image density was obtained from the average of 5 points.

Also, the average reflectance Dr of plain paper before image formation
Densitometer TC-6M manufactured by Tokyo Denshoku Co., Ltd. (%)
C, while a solid white image is printed on plain paper, and then the reflectance Ds (%) of the solid white image is measured.
Fog (%) was calculated by the following formula. fog (%) = Dr (%)-Ds (%) excellent: less than 1.0 (%) good: 1.0 to less than 1.5 (%) possible: 1.5 to less than 2.0 (%) somewhat Poor: Less than 2.0 to 3.0 (%) Poor: 3.0 (%) or more

The measurement was carried out at arbitrary 5 points, and the average value of the 5 points was used for each numerical value.

In the same machine, the solid density and fog after continuously running 80K on a chart in which five perfect circles were randomly arranged in the A4 size were measured in the same manner.

As a result, the toner of Example 1 had a high solid density both at the initial stage and after the endurance, and no fog caused by abrasion of the drum was observed, and a high-density good image was obtained.

Table 1 shows the aggregation degree of Examples and Comparative Examples, and Table 2 shows the electrophotographic characteristics.

Example 2 In the same manner as in Example 1, except that the external addition amount of silica was 1.0%, but 0.5%.
Toner 2 was prepared. When the degree of aggregation, the average degree of circularity and the amount of externally added toner were measured in the same manner as in Example 1, they were 17.7%, 0.980 and 0.48%, respectively. Applying this value to Equations 1 and 2, the relationship between the external addition amount of this toner and the cohesion degree Y is 80exp (-1.6X).
> Y and 75exp (-1.8X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, when the initial image and the image after endurance were evaluated, a good image was obtained without drum scraping.

[Example 3] Toner 3 was prepared in the same manner as in Example 1 except that the external addition amount of silica was 1.0% but was 0.3%. The aggregation degree of this toner is 30.
4%, average circularity 0.981, toner external addition amount 0.3
It was 2%. Applying this value to Equation 1, the relationship between the external addition amount of this toner and the cohesion degree Y is 80exp (-
1.6X)> Y, and 75exp (-1.8X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, when the initial image and the image after endurance were evaluated, a good image was obtained without drum scraping. Especially, fog after endurance, which is considered to be caused by scraping of the drum, was hardly seen.

Example 4 Toner 4 The toner prepared in Production Example 1 was used as it is as Toner 4. The aggregation degree of this toner was 42.3%, the average circularity was 0.981, and the toner external addition amount was 0%. Therefore, the relationship between the externally added amount X of this toner and the cohesion degree Y is 80exp (-1.6X).
> Y and 75exp (-1.8X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, the initial image and the image after endurance were evaluated. As a result, an image having no problem in practical use was obtained as the initial image, and particularly fog after endurance, which is considered to be caused by drum abrasion, was hardly seen.

(Toner Production Example 3) 150 g of the toner prepared in Toner Production Example 1 was weighed and introduced into a hybridization system (NHS-1 type) manufactured by Nara Machinery Co., Ltd. At that time, the processing conditions were as follows: rotation speed: 7200 rpm,
Processing time: 3 min, processing temperature: 52 ° C., to obtain a toner.

[Example 5] Toner 5 The toner prepared in Example 3 was externally added with 1.0% of the silica fine particles used in Example 1 in the same manner as in Example 1 to obtain toner 5. .
The obtained toner 5 has an average circularity of 0.977 and an aggregation degree of Y.
Was 12.3%. The amount of external addition was measured by the same method as in Example 1, and it was 0.98%. Therefore, the relationship between the external additive amount X of the toner 5 and the cohesion degree Y is 80e.
xp (-1.6X)> Y, and 75exp (-1.8)
X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, when the initial image and the image after endurance were evaluated, a good image was obtained without drum scraping.

[Example 6] Toner 6 was obtained in the same manner as in Example 5, except that the content of silica particles was changed from 1.0% to 0.3%. The obtained toner 6 had an average circularity of 0.976 and an aggregation degree Y of 32.0%. The external addition amount measured in the same manner as in Example 1 was 0.28%. Therefore, the relationship between the external additive amount X of the toner 6 and the cohesion degree Y is 80exp (-1.6X)> Y and 75exp.
(-1.8X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, when the initial image and the image after endurance were evaluated, a good image was obtained without drum scraping. Especially, fog after endurance, which is considered to be caused by scraping of the drum, was hardly seen.

[Example 7] Toner 7 was prepared by using the toner of Production Example 3 as it was. The toner thus obtained had an average circularity of 0.977 and an aggregation degree Y of 50.4. The external addition amount measured in the same manner as in Example 1 was 0%. Therefore, the relationship between the external additive amount X of the toner 7 and the cohesion degree Y is 80exp (-1.6X)> Y and 75exp.
(-1.8X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, the initial image and the image after endurance were evaluated. As a result, an image having no problem in practical use was obtained as the initial image, and particularly fog after endurance, which is considered to be caused by drum abrasion, was hardly seen.

Example 8 Preparation of Toner The same silica fine particles as those used in Example 1 were used in the toner prepared in Example 1.
Toner 8 was externally added in an amount of 0% as in Example 1. The obtained toner has an average circularity of 0.956 and an aggregation degree Y of 15.
It was 12%. The externally added amount X% of the toner 8 is set to the value of Example 1.
It was 0.97% when measured in the same manner as. Therefore, the relationship between the external additive amount X of the toner 8 and the aggregation degree Y is
80exp (-1.6X)> Y, 75exp (-1.
8X) <Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, when the initial image and the image after endurance were evaluated, an image having no practical problem was obtained as the initial image, and there was no problem with fog which is considered to be caused by drum abrasion.

Example 9 Toner 9 was prepared in the same manner as in Example 8 except that the amount of silica fine particles added externally was 0.3%. The toner has an average circularity of 0.957 and an aggregation degree of Y.
Was 45.1%. The external addition amount of silica measured in the same manner as in Example 1 was 0.31%. Therefore, the relationship between the external additive amount X of the toner 8 and the cohesion degree Y is 80e.
xp (-1.6X)> Y, and 75exp (-1.8)
X)> Y.

Using this toner in the same manner as in Example 1, GP
In 215, the initial image and the image after endurance were evaluated. As a result, an image having no problem in practical use was obtained as the initial image, and particularly fog after endurance, which is considered to be caused by drum abrasion, was hardly seen.

Example 10 The specific surface area of the silica used in Example 1 was 300 m ² / g (manufactured by Nippon Aerosil Co .; # 30).
Toner 10 was prepared in the same manner as in Example 1 except that (0) was used. The toner had an average circularity of 0.981 and an aggregation degree Y of 15.4%. The external addition amount of silica measured in the same manner as in Example 1 was 0.99%. Therefore, the relationship between the external additive amount X of the toner 8 and the cohesion degree Y is 80e.
xp (-1.6X)> Y, and 75exp (-1.8)
X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, the initial image and the image after endurance were evaluated. As a result, an image having no problem in practical use was obtained as the initial image, and particularly fog after endurance, which is considered to be caused by drum abrasion, was hardly seen.

(Manufacturing Example 4 of Toner) A manufacturing example of toner base particles is the same as in Manufacturing Example 1 of toner except that the crusher for finely crushing the coarsely pulverized product is changed to an air jet type fine pulverizer. A toner was prepared in exactly the same manner. The average particle size of this toner was measured to be 7.62.
The average circularity was 0.945.

[Comparative Example 1] Toner 11 was prepared by externally adding the same silica fine particles as used in Example 1 to the toner of Production Example 4 in the same manner as 1.2%. The obtained toner 11 has an average circularity of 0.943 and an aggregation degree Y of 31.1%.
Met. When the amount of silica added externally was measured by the same method as in Example 1, it was 1.22%. Therefore, the relationship between the external additive amount X of the toner 11 and the cohesion degree Y is 80exp.
(-1.6X) <Y and 75exp (-1.8X) <
The toner was Y, and the toner had a high degree of aggregation.

This toner was subjected to GP in the same manner as in Example 1.
In 215, when the initial image and the image after endurance were evaluated, an image with no practical problems was obtained in the initial stage, but after endurance, the fog value, which is considered to be caused by drum abrasion, was higher than that of the other toners.

[Comparative Example 2] Toner 12 was prepared in the same manner as Comparative Example 1 except that the amount of silica added was 1.0%. The average circularity of the obtained toner 12 is 0.94.
4, the cohesion degree Y was 31.2%. When the external addition amount of silica was measured by the same method as in Example 1, it was 0.98%. Therefore, the relationship between the external additive amount X of the toner 13 and the cohesion degree Y is 80exp (-1.6X) <Y, and 75
The exp (-1.8X) <Y, and the toner had a high degree of aggregation.

Using this toner in the same manner as in Example 1, GP
In 215, the initial image and the image after endurance were evaluated. As a result, the initial image density was slightly low, and the image density after endurance was lower than that of the other toners.

[Comparative Example 3] Toner 13 was prepared in the same manner as in the toner of Example 2 except that the same silica as in Example 1 was added to 1.2%. Toner 1 obtained
The average circularity of No. 3 was 0.982, and the cohesion degree Y was 8.0%. When the amount of silica added externally was measured by the same method as in Example 1, it was 1.22%. Therefore, toner 1
The relationship between the external additive amount X and the cohesion degree Y of 3 is 80exp (-
1.6X)> Y, and 75exp (-1.8X)> Y.

This toner was subjected to GP in the same manner as in Example 1.
In 215, when the initial image and the image after endurance were evaluated, a good image with high image density was obtained in the initial stage, but after endurance, the fog value, which is considered to be caused by drum abrasion, was higher than that of other toners. .

[Comparative Example 4] Toner 14 was prepared by using the toner of Production Example 4 as it was. Obtained Toner 14
The average circularity was 0.943 and the cohesion degree Y was 81.8%. When the external addition amount of silica was measured by the same method as in Example 1, it was 0%. Therefore, the relationship between the external additive amount X of the toner 14 and the cohesion degree Y is 80exp (-1.6
X) <Y and 75exp (-1.8X) <Y,
The toner had a high degree of aggregation.

Using this toner in the same manner as in Example 1, GP
In 215, when the initial image and the image after endurance were evaluated, the initial density was extremely low, and although the fog was not observed even after the endurance, the image density was extremely low.

[Comparative Example 5] The silica used in Example 1 had a specific surface area of 130 m ² / g (manufactured by Nippon Aerosil Co .; # 13).
Toner 15 was obtained in the same manner except that it was set to 0). The obtained toner 15 has an average circularity of 0.981 and an aggregation degree Y of 2
It was 0.6%. When the external addition amount of silica was measured by the same method as in Example 1, it was 0.98%. Therefore, the relationship between the external additive amount X of the toner 15 and the cohesion degree Y is 80
exp (-1.6X) <Y, and 75exp (-1.8)
X) <Y, and the toner had a high degree of aggregation.

GP2 was applied to this toner in the same manner as in Example 1.
In No. 15, when the initial image and the image after endurance were evaluated, a good image was obtained without drum scraping. Despite not satisfying the formulas 1 and 2, the initial characteristics and the drum scraping were good. The reason is that the formula was not established because the particle diameter of silica was out of the condition of the present invention. it was thought.

[0122]

[Table 1]

[0123]

[Table 2]

[0124]

EFFECTS OF THE INVENTION By using the toner of the present invention, it is possible to provide a toner having a high concentration while suppressing the external addition amount of the inorganic fine particles as much as possible. As a result, it is possible to realize a durable cartridge or drum unit without causing drum scraping even when used for a long period of time or by minimizing it.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a toner aggregation degree and an external addition amount, which is an essential condition of the present invention.

FIG. 2 is a model diagram showing the relationship between the presence state of an external additive on the toner surface and the toner surface irregularities.

FIG. 3 is a schematic view of an example of a mechanical pulverizer used in the toner pulverizing step of the present invention.

FIG. 4 is a schematic sectional view taken along the line DD ′ in FIG.

5 is a perspective view of the rotor shown in FIG.

[Explanation of symbols]

219: Pipe 220: Distributor 222: Bug filter 224: Suction filter 229: Collection cyclone 302: Powder outlet 310: Stator 311: Powder input port 312: rotating shaft 313: Casing 314: rotor 316: jacket 317: Cooling water supply port 318: Cooling water discharge port 321: Cooling generation means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuo Terauchi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Chika Negishi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H005 AA02 AA08 AA15 CA12 CA26                       CB13 EA05 EA07 EA10

Claims (5)

[Claims] 1. A magnetic toner containing at least a binder resin and a magnetic material, having a weight average diameter of 4 to 12 μm, a specific surface area of 175 m ² / g or more on the toner surface, and a silane coupling agent and It is a toner in which silica fine particles treated with silicone oil are externally added in an amount of 0 to 1.0% or less, and the external addition amount of the silica fine particles is X.
Mass%, X mass% When the cohesion degree when externally added is Y%,
A magnetic toner characterized in that the following formula is established between X and Y. Y ≦ 80exp (−1.6X) (Formula 1) 2. When the external addition amount of silica fine particles to the toner is X% by mass and the cohesion degree at the time of external addition of X% by mass is Y%, the following formula is established between X and Y. The magnetic toner according to claim 1. Y ≦ 75exp (-1.8X) (Formula 2) 3. The external addition amount of silica fine particles is 0 to 0.5.
The magnetic toner according to claim 1 or 2, wherein the content is less than or equal to mass%. 4. The external addition amount of silica fine particles is 0 to 0.3.
The magnetic toner according to claim 1 or 2, wherein the content is less than or equal to mass%. 5. The magnetic toner according to claim 1, which has an average circularity of 0.960 or more.