JP7523918B2 - Magnetic carrier and two-component developer - Google Patents

Description

This disclosure relates to a magnetic carrier and a two-component developer used in an image forming method for visualizing an electrostatic image using electrophotography.

Conventionally, in the electrophotographic image forming method, a method is generally used in which an electrostatic latent image is formed on an electrostatic latent image carrier by using various means, and a toner is attached to the electrostatic latent image to develop it. In this development, a two-component development method is widely adopted in which carrier particles called a magnetic carrier are mixed with the toner, and the toner is triboelectrically charged to give an appropriate amount of positive or negative charge to the toner, and the charge is used as a driving force for development.
In the two-component development method, the magnetic carrier can be given functions such as stirring, transporting, and charging the developer, so the division of functions between the magnetic carrier and the toner is clear, which has the advantage of good controllability of developer performance.

In recent years, as full-color electrophotographic copying machines have come into widespread use, there has been a demand for higher image quality as well as stability during long-term use.
In order to achieve high image quality, it is essential to achieve high image reproducibility in the processes of development, transfer, fixing, etc. In particular, in the transfer process, high image reproducibility can be achieved by efficiently transferring the toner developed on the electrostatic latent image carrier onto the intermediate transfer body or media.
To obtain high transferability, the electric field strength that each toner particle receives from the transfer bias must be greater than the adhesive force between the toner particle and the electrostatic latent image carrier. Adhesion forces are broadly divided into non-electrostatic adhesive forces, such as van der Waals forces, and electrostatic adhesive forces, such as electrostatic reflective forces.
Therefore, in order to improve the transferability, a method has been reported in which the toner particles are coated with a large amount of an external additive such as silica particles to reduce the non-electrostatic adhesion (Patent Document 1).

JP 2018-49239 A

The toner described in Patent Document 1 has improved the transferability problem.
However, in long-term use, a part of the external additive may migrate from the surface of the toner particles and adhere to the magnetic carrier. In particular, when the magnetic carrier is contaminated with a negative external additive, it has been found that the charging ability is reduced, the durability stability of the image density is reduced, and density unevenness and fogging occur within the image surface.
From the above, we believe that there is a trade-off between high image reproducibility and the contamination resistance of the magnetic carrier. There is an urgent need to develop a magnetic carrier and a two-component developer that can break this trade-off and achieve high image quality even with long-term use.
The present disclosure provides a magnetic carrier and a two-component developer that are excellent in durability and stability of image density and can suppress uneven density and fogging within an image surface.

（式中、Ｒ _１ は、炭素数６～１２の鎖状アルキル基を表し、Ｒ _２ は、それぞれ独立して、メチル基又はエチル基を表す。） A magnetic carrier,
The magnetic carrier has a compound having an amino group on the surface of a magnetic core particle, and further has a resin coating layer thereon,
the compound having an amino group is exposed on at least a part of the surface of the magnetic carrier,
a nitrogen atom concentration detected by a surface analysis of the magnetic carrier by X-ray photoelectron spectroscopy is 0.40 atomic % or more and 1.00 atomic % or less;
The magnetic core particle comprises a porous magnetic particle and a filler present in the pores of the porous magnetic particle;
The average pore size of the porous magnetic particles is 0.40 μm or more and 0.60 μm or less,
The porous magnetic particles have an integrated pore volume of 40 mm ³ /g or more and 60 mm ³ /g or less;
The magnetic carrier is characterized in that the resin coating layer contains 5.0 to 20.0 parts by mass of a silane compound represented by the following formula (3) per 100 parts by mass of the coating resin .

(In the formula, R ₁ represents a chain alkyl group having 6 to 12 carbon atoms, and R ₂ each independently represents a methyl group or an ethyl group.)

This disclosure makes it possible to provide a magnetic carrier and a two-component developer that have excellent durability and stability of image density and can suppress uneven density and fogging within the image surface.

Schematic diagram of thermal sphering treatment device Schematic diagram of the device for measuring the charge amount Schematic diagram of coating resin content definition method in GPC molecular weight distribution curve Schematic diagram of coating resin content definition method in GPC molecular weight distribution curve Pore distribution example

The expressions "XX to YY" or "XX to YY" representing a numerical range mean a numerical range including the endpoints, that is, the lower limit and the upper limit, unless otherwise specified.
When numerical ranges are stated in stages, the upper and lower limits of each numerical range can be combined in any way.

The present disclosure provides a magnetic carrier, comprising:
The magnetic carrier has a compound having an amino group on the surface of a magnetic core particle, and further has a resin coating layer thereon,
the compound having an amino group is exposed on at least a part of the surface of the magnetic carrier,
The magnetic carrier has a nitrogen atom concentration of 0.40 atomic % or more and 1.00 atomic % or less, as detected by surface analysis of the magnetic carrier using X-ray photoelectron spectroscopy.

In the magnetic carrier, the compound having an amino group is exposed on at least a portion of the magnetic carrier surface. By exposing the compound having an amino group on the magnetic carrier surface, contamination of the magnetic carrier charging site by external additives transferred from the toner can be suppressed. As a result, the image density exhibits durable stability over long-term use, and density unevenness and fogging within the image surface can be suppressed.

The present inventors believe that the reason for solving the above problems is as follows.
The magnetic carrier surface contains a compound having an amino group and a resin coating layer component capable of imparting a negative charge to the toner. When a negative external additive is attached to the resin coating layer, it is believed that the charge amount is likely to decrease due to contamination of the charging site of the magnetic carrier.
However, it is presumed that compounds having amino groups are positively polarized and tend to attract external additives having negative polarity.
Therefore, even if a negatively charged external additive is transferred from the toner to the magnetic carrier, the compound having an amino group traps the external additive, protecting the resin coating layer components that are the charging sites. As a result, it is presumed that the image density has excellent durability and stability even after long-term use, and density unevenness and fogging within the image surface can be suppressed.

The nitrogen atom concentration detected by surface analysis of the magnetic carrier by X-ray photoelectron spectroscopy (XPS) is 0.40 atomic % or more and 1.00 atomic % or less.
The nitrogen atoms detected by surface analysis of the magnetic carrier by X-ray photoelectron spectroscopy (XPS) are derived from compounds having amino groups. When the nitrogen atom concentration is within the above range, the compounds having amino groups are present in an appropriate amount on the magnetic carrier surface, and even if a negatively charged external additive is transferred from the toner to the magnetic carrier, the compounds having amino groups trap the external additive, protecting the resin coating layer components that are the charging sites. As a result, it is believed that the image density has excellent durability and stability even when used for a long period of time, and uneven density and fogging in the image surface can be suppressed.
The nitrogen atomic concentration is preferably 0.45 atomic % or more and 0.70 atomic % or less, and more preferably 0.50 atomic % or more and 0.60 atomic % or less.
The nitrogen atom concentration can be controlled by the ratio Ar of the total area of Lu to the total projected area of the magnetic carrier.

Lu is a portion having a luminance range of 140 to 255 in a backscattered electron image of the magnetic carrier photographed with a scanning electron microscope at an accelerating voltage of 2.0 kV, when the backscattered electron image is obtained as an 8-bit, 256-level grayscale image. That is, Lu is a portion with high luminance. Specifically, it is a region in which no resin coating layer components are present and the magnetic core particles are exposed, whereby metal components derived from the magnetic core particles can be detected.
Here, the surfaces of the magnetic core particles have ferrite-derived hydroxyl groups, and when the surfaces of the magnetic core particles are treated with a compound having an amino group, the hydroxyl groups react with silanol, resulting in a chemically modified surface of the magnetic core particles.
Therefore, Lu is considered to be the portion where the compound having an amino group is exposed on the surface of the magnetic core particle. The method for controlling the ratio Ar of the total area of Lu will be described later.

In a backscattered electron image of the magnetic carrier taken with a scanning electron microscope at an accelerating voltage of 2.0 kV, the backscattered electron image is obtained as an 8-bit, 256-level grayscale image, and when the portion with a luminance range of 140 to 255 is designated as Lu, the diameter of Lu is preferably 0.10 μm or more and 1.00 μm or less, more preferably 0.20 μm or more and 0.90 μm or less, and even more preferably 0.40 μm or more and 0.60 μm or less.

The diameter of Lu increases as the compound having an amino group is exposed on the surface of the magnetic core particle.
Therefore, the diameter of Lu can be controlled by the degree of exposure of the compound having an amino group on the surface of the magnetic core particle.
The degree of exposure of the compound having an amino group on the surface of the magnetic core particles can be controlled by the treatment amount of the compound having an amino group, the content of the filler, and the pore volume.
When the amount of the compound having an amino group to be treated is increased, the amount of the compound having an amino group exposed on the carrier surface increases.
Furthermore, increasing the content of the filler reduces the specific surface area of the magnetic core particles, resulting in a larger amount of the compound having an amino group per unit area of the carrier surface, and therefore a larger exposed area.
In addition, increasing the pore volume increases the specific surface area of the magnetic core particles, which results in a smaller amount of the compound having an amino group per unit area of the carrier surface, resulting in a smaller exposure.

It is assumed that when the diameter of Lu is within the above range, a suitable amount of compound having an amino group is present on the magnetic carrier surface. Even if a negatively charged external additive is transferred from the toner to the magnetic carrier, the compound having an amino group traps the external additive, protecting the resin coating layer components that are the charging sites. As a result, it is believed that the image density has excellent durability and stability even with long-term use, and density unevenness and fogging within the image surface can be suppressed.

The average value of the closest distance between Lu is preferably 1.0 μm or more and 3.0 μm or less, more preferably 1.5 μm or more and 2.5 μm or less. It is presumed that when a compound having an amino group traps an external additive, that portion becomes a non-charged site. It is considered that when the average value of the closest distance between Lu is in the above range, the non-charged site is unlikely to localize even after trapping the external additive, so that charging is stable.
The average value of the closest distance between Lu particles can be controlled by the particle size of the grains (crystal particles) of the porous magnetic particles.
As the grain size decreases, the convex portions on the surface of the magnetic carrier resulting from the grains become smaller, and the average value of the closest distance becomes smaller.
The average horizontal Feret diameter of the grains is preferably 0.1 μm to 5.0 μm, more preferably 1.0 μm to 3.0 μm, and further preferably 1.5 μm to 2.5 μm.

The ratio Ar of the total area of Lu to the total projected area of the magnetic carrier, calculated from the following formula (1), is preferably 5.0% or more and 15.0% or less.
Ar = (total area of Lu / total projected area of magnetic carrier) × 100 (1)
The Ar content is more preferably 6.0% or more and 14.0% or less, and further preferably 8.0% or more and 12.0% or less.
It is presumed that when Ar is in the above range, a compound having an amino group is present in an appropriate amount on the magnetic carrier surface. Even if a negatively charged external additive is transferred from the toner to the magnetic carrier, the compound having an amino group traps the external additive, and the resin coating layer component, which is the charging site, is protected. As a result, it is believed that the image density has excellent durability and stability even when used for a long period of time, and density unevenness and fogging in the image surface can be suppressed.

Ar increases as the amount of the compound having an amino group is exposed on the surface of the magnetic core particle.
Therefore, Ar can be controlled by the degree of exposure of the compound having an amino group on the surface of the magnetic core particle.
The degree of exposure of the compound having an amino group on the surface of the magnetic core particles can be controlled by the treatment amount of the compound having an amino group, the content of the filler, and the pore volume.
For example, when the amount of the compound having an amino group to be treated is increased, the amount of the compound having an amino group exposed on the carrier surface increases.
Furthermore, increasing the content of the filler reduces the specific surface area of the magnetic core particles, resulting in a larger amount of the compound having an amino group per unit area of the carrier surface, and therefore a larger exposed area.
In addition, increasing the pore volume increases the specific surface area of the magnetic core particles, which results in a smaller amount of the compound having an amino group per unit area of the carrier surface, resulting in a smaller exposure.

The magnetic core particles preferably comprise porous magnetic particles and a filler present in the pores of the porous magnetic particles. The average pore size of the porous magnetic particles is preferably 0.40 μm or more and 0.60 μm or less, more preferably 0.45 μm or more and 0.55 μm or less.
The smaller the pore size of the porous magnetic particles, the more difficult it is for the filler to penetrate and the more filler is present on the surface of the magnetic core particles, whereas the larger the pore size of the porous magnetic particles, the more easily the filler penetrates and the less filler is present on the surface of the magnetic core particles.
When the average pore size of the porous magnetic particles is within the above range, the filler component is present on the surface of the magnetic core particles, and the magnetic core particles have an appropriate specific surface area.
Therefore, even if the magnetic core particles are treated with a compound having an amino group and then a resin coating layer is formed, the compound having an amino group is appropriately exposed on the magnetic carrier surface. As a result, the compound having an amino group traps the negative external additive, and the resin coating layer components, which are the charging sites, are protected. As a result, it is believed that the image density has excellent durability and stability even when used for a long period of time, and density unevenness and fogging in the image surface can be suppressed.

The cumulative pore volume of the porous magnetic particles is from 40 mm ³ /g to 60 mm ³ /g, and preferably from 45 mm ³ /g to 55 mm ³ /g.
The smaller the pore volume of the porous magnetic particles, the more difficult it is for the filler to penetrate and the more filler will be present on the surface of the magnetic core particles, whereas the larger the pore volume of the porous magnetic particles, the more easily the filler will penetrate and the less filler will be present on the surface of the magnetic core particles.
When the pore volume of the porous magnetic particles is within the above range, the filler component is present on the surface of the magnetic core particles, and the magnetic core particles have an appropriate specific surface area.
Therefore, even if the magnetic core particles are treated with a compound having an amino group and then a resin coating layer is formed, the compound having an amino group is appropriately exposed on the magnetic carrier surface. As a result, the compound having an amino group traps the negative external additive, and the resin coating layer component, which is the charging site, is protected. As a result, even if used for a long period of time, it is believed that the image density has excellent durability and stability, and density unevenness and fogging in the image surface can be suppressed.

The content of the compound having an amino group is preferably 0.010 parts by mass or more and 0.100 parts by mass or less, and more preferably 0.060 parts by mass or more and 0.080 parts by mass or less, relative to 100 parts by mass of the magnetic core particles.
It is presumed that within the above range, a compound having an amino group is present in an appropriate amount on the magnetic carrier surface. Even if a negatively charged external additive is transferred from the toner to the magnetic carrier, the compound having an amino group traps the external additive, and the resin coating layer component, which is the charging site, is protected. As a result, it is believed that the image density has excellent durability and stability even when used for a long period of time, and density unevenness and fogging in the image surface can be suppressed.

The content of the filler is preferably 1.0 part by mass or more and 8.0 parts by mass or less, more preferably 1.0 part by mass or more and 7.0 parts by mass or less, and even more preferably 1.0 part by mass or more and 5.0 parts by mass or less, relative to 100 parts by mass of the porous magnetic particles.
When the content of the filler is within the above range, the filler component is present on the surface of the magnetic core particles, and the magnetic core particles have an appropriate specific surface area.
Therefore, even if the magnetic core particles are treated with a compound having an amino group and then a resin coating layer is formed, the compound having an amino group is appropriately exposed on the magnetic carrier surface. As a result, the compound having an amino group traps the negative external additive, and the resin coating layer component, which is the charging site, is protected. As a result, even if used for a long period of time, it is believed that the image density has excellent durability and stability, and density unevenness and fogging in the image surface can be suppressed.

The magnetic carrier can be used in a two-component developer.
The two-component developer preferably includes a magnetic carrier and a toner, the toner being negatively chargeable, and the toner has toner particles and inorganic fine particles, the inorganic fine particles being negatively chargeable.

The magnetic carrier has a resin coating layer. The resin coating layer preferably contains a resin A and a resin B.
The resin A is
(a) a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group;
(b) a macromonomer having a polymer moiety which is a polymer of at least one monomer selected from the group consisting of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate, and a reactive moiety bonded to the polymer moiety and having a reactive C═C double bond;
It is preferable that the copolymer is a copolymer of monomers containing the following:
The resin B is
(c) a styrene-based monomer;
(d) a (meth)acrylic acid ester monomer represented by the following formula (2):
It is preferable that the copolymer is a copolymer of monomers containing the following:
In addition, it is preferable that a peak derived from the resin B exists in a molecular weight range of 1,000 to 9,500 in the molecular weight distribution of the resin coating layer by gel permeation chromatography (GPC).

(In formula (2), _R1 represents H or _CH3 , and n represents an integer of 2 to 8.)

When the macromonomer portion is located in the side chain of a molecule of resin A, the macromonomer portion is three-dimensionally bulky, so the molecules of resin A cannot approach each other, and a moderate amount of space may be present. Resin B, a low molecular weight resin, enters the resulting space, thereby exerting the charge relaxation properties derived from resin B. In addition, since resin A is present on the surface of the magnetic carrier coated with the resin coating layer, it is believed that the toughness and abrasion resistance of the resin coating layer are improved.

From the viewpoints of extending the life of the magnetic carrier and reducing unevenness in density and fogging within an image, it is more preferable that the peak derived from the resin B exists in the molecular weight range of 2,000 to 9,000.
When the peak derived from the resin B has a molecular weight of 1000 or more, the toughness and abrasion resistance of the resin coating layer are improved, peeling or scraping of the resin coating layer during long-term use is suppressed, and changes in image density tend to be improved.When the peak derived from the resin B has a molecular weight of 9000 or less, the charge relaxation property derived from the resin B is fully expressed, and density uniformity and fog in the image surface tend to be improved.
The molecular weight of the peak derived from the resin B can be adjusted by controlling the degree of polymerization by the reaction time during the production of the resin B.

In the molecular weight distribution of the resin coating layer by gel permeation chromatography (GPC), the peak derived from the resin A is preferably in the range of molecular weight of 25,000 to 70,000, more preferably in the range of 40,000 to 60,000.
When the peak derived from the resin A has a molecular weight of 25000 or more, the toughness and abrasion resistance of the resin coating layer can be maintained, peeling or scraping of the resin coating layer during long-term use can be suppressed, and changes in image density can also be suppressed. When the peak derived from the resin A has a molecular weight of 70000 or less, the charge relaxation property of the resin coating layer can be sufficiently obtained, and reduction of density unevenness in the image surface and fogging can be suppressed.
The molecular weight of the peak derived from the resin A can be adjusted by controlling the degree of polymerization by the reaction time during the production of the resin A.

[Resin A]
The resin A used in the resin coating layer is a vinyl resin which is a copolymer of a vinyl monomer having a cyclic hydrocarbon group in the molecular structure with another vinyl monomer, and among them, a copolymer of a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group and a macromonomer is preferred.
The polymer (resin A) of a monomer containing at least a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group smoothes the coating surface of the resin layer coated on the surface of the magnetic core particle. As a result, it has the function of suppressing adhesion of toner-derived components to the magnetic carrier and suppressing a decrease in chargeability. In addition, the macromonomer improves the adhesion between the resin coating layer and the magnetic core particle, improving image density stability.

Examples of the (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group include cyclobutyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, cycloheptyl acrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, dicyclopentenyl methacrylate, and dicyclopentanyl methacrylate. These may be used alone or in combination of two or more.

The macromonomer has a polymer portion and a reactive portion bonded to the polymer portion. The polymer portion may be a polymer of at least one monomer selected from the group consisting of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. The reactive portion has a reactive C=C double bond. The reactive portion having a reactive C=C double bond includes, for example, a vinyl group, an acryloyl group, or a methacryloyl group.

The ratio of the (meth)acrylic acid ester monomer having the alicyclic hydrocarbon group is preferably 50.0 mol% to 99.5 mol%, and more preferably 60.0 mol% to 99.0 mol%. By making it 50.0 mol% or more, the toughness and abrasion resistance of the resin coating layer can be maintained, peeling and scraping of the resin coating layer during long-term use can be suppressed, and changes in image density can also be suppressed. On the other hand, by making it 99.5 mol% or less, the charge relaxation properties of the resin coating layer can be sufficiently obtained, and reduction of density unevenness in the image surface and fogging can be suppressed.

The ratio of the macromonomer is preferably 0.1 mol% to 5.0 mol%, and more preferably 0.2 mol% to 2.0 mol%. By making it 0.1 mol% or more, the charge relaxation properties of the resin coating layer are sufficiently obtained, and uneven density in the image surface and deterioration of fine line reproducibility are suppressed. On the other hand, by making it 5.0 mol% or less, the toughness and abrasion resistance of the resin coating layer can be maintained, peeling and scraping of the resin coating layer during long-term use can be suppressed, and changes in image density can also be suppressed.

From the perspective of coating stability, the weight average molecular weight (Mw) of resin A is preferably 20,000 to 75,000, and more preferably 25,000 to 70,000.

Furthermore, a (meth)acrylic monomer other than the above-mentioned (meth)acrylic acid ester having an alicyclic hydrocarbon group may be used as a monomer to form a copolymer.
Other (meth)acrylic monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate (n-butyl, sec-butyl, iso-butyl or tert-butyl; the same applies below), butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, acrylic acid, methacrylic acid, etc. These may be used alone or in combination of two or more.

The peak molecular weight of the macromonomer portion of the resin A is preferably 1000 to 9500. When the peak molecular weight of the macromonomer portion of the resin A is 1000 or more, the penetration of the resin B into the macromonomer portion described above is more effectively expressed, the toughness and abrasion resistance of the resin coating layer are improved, and changes in image density are further suppressed. On the other hand, when the peak molecular weight of the macromonomer portion of the resin A is 9500 or less, the charge relaxation property of the resin coating layer is sufficiently obtained, and the reduction of density unevenness in the image surface and fogging are suppressed.

[Resin B]
Resin B used in the resin coating layer is a copolymer of monomers containing a styrene-based monomer such as styrene and vinyl toluene, and a (meth)acrylic acid ester monomer represented by the above formula (2).
By including a styrene-based monomer in the copolymer, the glass transition point can be increased even with the same molecular weight compared to a resin that does not include a styrene-based monomer, and the toughness of the resin coating layer can be maintained even with a low molecular weight.In addition, by including a (meth)acrylic acid ester monomer represented by formula (2), the affinity with the macromonomer of resin A, which has a similar structure, is increased, and the penetration of the resin B into the macromonomer portion described above is more effectively expressed, and the toughness and abrasion resistance of the resin coating layer can be improved while reducing uneven density in the image surface and suppressing fogging.

It is also believed that the styrene moiety of resin B interacts with the compound having an amino group. It is known that the benzyl position of the styrene moiety is easily anionized by the adjacent aromatic. It is predicted that the lone electron pair of the nitrogen atom in the compound having an amino group will receive the hydrogen atom at the benzyl position of the styrene moiety, and the compound having an amino group itself will tend to become positive polarity.
Therefore, it is believed that by including resin B, which contains a styrene portion, in the resin coating layer, the compound having an amino group becomes positive.
Even if a negatively charged external additive is transferred from the toner to the magnetic carrier, the compound having an amino group traps the external additive, protecting the resin coating layer components that are the charging sites. As a result, it is presumed that the image density has excellent durability and stability even after long-term use, and density unevenness and fogging within the image surface can be suppressed.

The resin used as resin B is not particularly limited, but examples thereof include styrene-based copolymers such as styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, and styrene-octyl methacrylate copolymer. These may be used alone or in combination.

The weight average molecular weight (Mw) of the resin B is preferably 1000 to 9500, and more preferably 1500 to 9000. When the Mw of the resin B is 1000 or more, the toughness and abrasion resistance of the resin coating layer are further improved, and changes in image density are further suppressed. When the Mw of the resin B-1 is 9500 or less, the reduction in density unevenness and fogging within the image surface are further suppressed.

The ratio of the (meth)acrylic acid ester monomer represented by formula (2) used in the above resin B is preferably 0.1 mol% to 5.0 mol%, and more preferably 0.2 mol% to 2.0 mol%. By setting it within the above range, the toughness of the resin coating layer is increased, and the affinity between the (meth)acrylic acid ester monomer portion and the macromonomer portion is further increased, so that it is possible to simultaneously improve the toughness and abrasion resistance of the resin coating layer, reduce density unevenness within the image surface, and suppress fogging.

The amount of coating resin is preferably 1.0 to 3.0 parts by mass per 100 parts by mass of magnetic core particles treated with a compound having an amino group. When the amount of coating resin is 1.0 part by mass or more, the toughness and abrasion resistance of the resin are increased, and changes in image density are suppressed. When the amount of coating resin is 3.0 parts by mass or less, the charging relaxation is further increased, and the reduction in density unevenness in the image surface and fogging are further suppressed.
The ratio of resin A to resin B in the coating resin (resin A/resin B) is preferably 50/50 to 90/10, and more preferably 65/35 to 80/20.

[Silane compounds]
The resin coating layer may contain a silane compound represented by the following formula (3): The amount of the silane compound is preferably 5.0 parts by mass to 20.0 parts by mass per 100 parts of the coating resin (total of resin A and resin B).
It is presumed that the above range makes it easier for the silane compound in the resin coating layer to interact with the compound having an amino group on the surface of the magnetic core particle.The silicon atom of the silane compound represented by the following formula (3) is considered to have positive polarity due to the electron-withdrawing property of the oxygen atom of the alkoxy group.
Therefore, it is considered that the lone pair of electrons of the nitrogen atom in the compound having an amino group is easily coordinated to the silicon atom, and the silicon atom is in a 5-coordinated state. Since the nitrogen atom has its lone pair coordinated to the silicon atom, the nitrogen atom itself has positive polarity.

When some of the nitrogen atoms become positive, electrons are instantly transferred, and it is expected that the electrons are delocalized within the compound having an amino group, and the entire compound becomes positive.
Therefore, when a silane compound is contained in the resin coating layer, it is considered that the compound having an amino group exposed on the magnetic carrier surface is likely to become positive. Even if a negative external additive is transferred from the toner to the magnetic carrier, the compound having an amino group traps the external additive, and the resin coating layer component, which is the charging site, is protected. As a result, it is presumed that the image density has excellent durability and stability even when used for a long period of time, and density unevenness and fogging in the image surface can be suppressed.

R ₁ represents a chain alkyl group having 6 to 12 carbon atoms, and R ₂ each independently represents a methyl group or an ethyl group.

[Particles with electrical conductivity, particles with charge controllability]
The resin coating layer may contain conductive particles or particles having charge control properties.
Examples of conductive particles include carbon black, magnetite, graphite, zinc oxide, and tin oxide.
The amount of conductive particles added is preferably 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the coating resin in order to adjust the resistance of the magnetic carrier.
Examples of particles having charge controllability include organic metal complex particles, organic metal salt particles, chelate compound particles, monoazo metal complex particles, acetylacetone metal complex particles, hydroxycarboxylic acid metal complex particles, polycarboxylic acid metal complex particles, polyol metal complex particles, polymethyl methacrylate resin particles, polystyrene resin particles, melamine resin particles, phenolic resin particles, nylon resin particles, silica particles, titanium oxide particles, and alumina particles.
The amount of the particles having charge controllability added is preferably 0.5 parts by mass or more and 50.0 parts by mass or less with respect to 100 parts by mass of the coating resin in order to adjust the amount of triboelectric charge.

Next, the magnetic core particles will be described.
[Magnetic core particles]
As the magnetic core particles used in the magnetic carrier, known magnetic core particles can be used, but it is preferable to use magnetic material-dispersed resin particles in which a magnetic material is dispersed in a resin component, or porous magnetic particles containing resin in the pores. These can reduce the true density of the magnetic carrier, thereby reducing the load on the toner. This makes it possible to reduce the deterioration of image quality even with long-term use, and to reduce the frequency of replacing the two-component developer composed of toner and magnetic carrier. However, instead of magnetic material-dispersed resin particles or porous magnetic particles, commercially available magnetic core particles may be used.

As the magnetic material component used in the magnetic material-dispersed resin particles, various magnetic iron compound particle powders can be used, such as magnetite particle powder, maghemite particle powder, or magnetic iron oxide particle powder containing one or more selected from silicon oxide, silicon hydroxide, aluminum oxide, and aluminum hydroxide in addition to the above, magnetoplumbite-type ferrite particle powder containing barium, strontium, or barium-strontium, and spinel-type ferrite particle powder containing one or more selected from manganese, nickel, zinc, lithium, and magnesium. Among these, magnetic iron oxide particle powder can be preferably used.

In addition to the above magnetic components, non-magnetic inorganic compound particles such as non-magnetic iron oxide particles such as hematite particles, non-magnetic ferric oxide hydrous particles such as goethite particles, titanium oxide particles, silica particles, talc particles, alumina particles, barium sulfate particles, barium carbonate particles, cadmium yellow particles, calcium carbonate particles, and zinc oxide particles can be used in combination with the magnetic iron compound particles.
When the magnetic iron compound particles and the non-magnetic inorganic compound particles are used in combination, the mixing ratio thereof is preferably such that the magnetic iron compound particles account for at least 30 mass %.

The magnetic iron compound particles are preferably wholly or partly treated with a lipophilic treatment agent.
The lipophilic treatment agent used in this case may be an organic compound having one or more functional groups selected from an epoxy group, an amino group, a mercapto group, an organic acid group, an ester group, a ketone group, a halogenated alkyl group, and an aldehyde group, or a mixture thereof.
The organic compound having a functional group is preferably a coupling agent, more preferably a silane coupling agent, a titanium coupling agent, or an aluminum coupling agent, and particularly preferably a silane coupling agent.

The binder resin constituting the magnetic material-dispersed resin particles is preferably a thermosetting resin.
Examples of thermosetting resins include phenol resins, epoxy resins, and unsaturated polyester resins, and it is preferable to use phenol resins, which are inexpensive and easy to manufacture, such as phenol-formaldehyde resins.
The content ratio of the binder resin and the magnetic iron compound particles constituting the magnetic material-dispersed resin particles is preferably 1% by mass to 20% by mass of the binder resin and 80% by mass to 99% by mass of the magnetic iron compound particles.

Next, a method for producing the magnetic material-dispersed resin particles will be described.
For example, as described in the examples below, the magnetic material-dispersed resin particles can be produced by stirring phenols and aldehydes in an aqueous medium in the presence of magnetic inorganic compound particles and a basic catalyst, and then reacting and curing the phenols and aldehydes to produce composite particles containing inorganic compound particles such as magnetic iron oxide particles and a phenol resin.
Alternatively, it can be produced by a so-called kneading and grinding method in which a binder resin containing inorganic compound particles such as magnetic iron oxide particles is ground.
The former method is preferred in order to easily control the particle size of the magnetic carrier and to obtain a sharp particle size distribution.

Next, the porous magnetic particles will be described.
The material of the porous magnetic particles is preferably magnetite or ferrite, and more preferably, the material of the porous magnetic particles is ferrite, since this allows the porous structure of the porous magnetic particles to be controlled and the resistance to be adjusted.

Ferrite is a sintered body represented by the following general formula:
(M1 ₂ O) _x (M2O) _y (Fe ₂ O ₃ ) _z
(In the formula, M1 is a monovalent metal, M2 is a divalent metal, and when x+y+z=1.0, x and y are each in the range of 0≦(x,y)≦0.8, and z is in the range of 0.2<z<1.0.)
In the formula, it is preferable to use one or more metal atoms selected from the group consisting of Li, Fe, Mn, Mg, Sr, Cu, Zn, and Ca as M1 and M2. In addition, Ni, Co, Ba, Y, V, Bi, In, Ta, Zr, B, Mo, Na, Sn, Ti, Cr, Al, Si, and rare earth elements can also be used.

For magnetic carriers, it is preferable to maintain an appropriate amount of magnetization, set the pore size within the desired range, and optimize the surface irregularities of the porous magnetic particles. It is also preferable to be able to easily control the speed of the ferritization reaction and to optimally control the resistivity and magnetic force of the porous magnetic particles. From these viewpoints, Mn-based ferrites, Mn-Mg-based ferrites, Mn-Mg-Sr-based ferrites, and Li-Mn-based ferrites that contain Mn element are more preferable.

An example of a production process in which porous magnetic particles are used as the magnetic core particles will be described in detail below.
<Step 1 (weighing and mixing step)>
The raw materials for the ferrite are weighed and mixed.
The ferrite raw material may be metal particles of the above-mentioned metal elements, or oxides, hydroxides, oxalates, carbonates, or the like thereof.
Examples of mixing devices include a ball mill, a planetary mill, a Giotto mill, and a vibration mill. In particular, a ball mill is preferred from the viewpoint of mixing properties.
Specifically, the weighed ferrite raw material and balls are placed in a ball mill, and the mixture is pulverized and mixed for 0.1 to 20.0 hours.

<Step 2 (Pre-firing step)>
The crushed and mixed ferrite raw material is pre-fired in air or nitrogen at a firing temperature of 700°C to 1200°C for 0.5 to 5.0 hours to form ferrite. For firing, the following furnaces are used, for example: burner-type incinerator, rotary-type firing furnace, electric furnace, etc.

<Step 3 (pulverization step)>
The calcined ferrite produced in step 2 is pulverized in a pulverizer.
The pulverizer is not particularly limited as long as it can produce the desired particle size, and examples thereof include a crusher, a hammer mill, a ball mill, a bead mill, a planetary mill, and a Giotto mill.
In order to obtain a pulverized ferrite product with a desired particle size, it is preferable to control the material, particle size, and operation time of the balls and beads used in a ball mill or a bead mill. Specifically, in order to reduce the particle size of the calcined ferrite slurry, balls with a heavy true density may be used or the pulverization time may be extended. In addition, in order to widen the particle size distribution of the calcined ferrite, balls or beads with a heavy true density may be used and the pulverization time may be shortened. In addition, calcined ferrite with a wide distribution can be obtained by mixing multiple calcined ferrites with different particle sizes.
In addition, the wet type of ball mill or bead mill is more preferable than the dry type because the crushed product does not fly up in the mill and the crushing efficiency is higher.

<Step 4 (granulation step)>
To the pulverized calcined ferrite, water, a binder, and, if necessary, a pore adjusting agent, such as a foaming agent or resin particles, are added.
Examples of the foaming agent include sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, ammonium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, and ammonium carbonate.
Examples of resin particles include polyester, polystyrene, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, and styrene-α-chloromethacrylate copolymer. styrene copolymers such as styrene-methyl acetate copolymers, styrene-acrylonitrile copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, and styrene-acrylonitrile-indene copolymers Polymers: polyvinyl chloride, phenolic resins, modified phenolic resins, maleic resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins; aliphatic polyhydric alcohols, aliphatic dicarboxylic acids, aromatic dicarboxylic acids, aromatic dialcohols and polyester resins having a monomer selected from diphenols as a structural unit; polyurethane resins, polyamide resins, polyvinyl butyral, terpene resins, coumarone-indene resins, petroleum resins, polyester units and vinyl polymer units Examples include fine particles of hybrid resins.

As the binder, for example, polyvinyl alcohol is used.
In step 3, when wet pulverization is performed, it is preferable to take into consideration the water contained in the ferrite slurry and to add a binder and, if necessary, a pore regulator.
If necessary, a dispersant may be added to the ferrite slurry. There are no particular limitations on the dispersant, but for example, ammonium polycarboxylate may be used.
The obtained ferrite slurry is dried and granulated using a spray dryer in a heated atmosphere at 100° C. to 200° C. The spray dryer is not particularly limited as long as it can obtain the desired particle size of the porous magnetic particles. For example, a spray dryer can be used.
The obtained granulated material may be subjected to particle size adjustment and then heated in a rotary electric furnace or the like at a firing temperature in the range of 700° C. to 1200° C. for 0.5 to 5.0 hours to remove organic substances such as dispersants and binders.

<Step 5 (Main Firing Step)>
Next, the granulated product is fired at 800° C. to 1400° C. for 1 hour to 24 hours.
By increasing the sintering temperature and lengthening the sintering time, the sintering of the porous magnetic particles proceeds, resulting in a smaller pore size and a reduced number of pores.

<Step 6 (sorting step)>
After the sintered particles are crushed as described above, they may be classified or sieved to remove coarse particles and fine particles, if necessary.
It is more preferable that the volume distribution based 50% particle size (D50) of the magnetic core particles is 18.0 μm to 68.0 μm in order to suppress adhesion of the magnetic carrier to the image and roughness.

<Process 7 (filling process)>
The physical strength of porous magnetic particles can be reduced depending on the internal pore volume. In order to increase the physical strength of the particles as a magnetic carrier, at least some of the pores of the porous magnetic particles are filled with a resin. It is preferable to carry out the above steps. The amount of resin filled in the porous magnetic particles is preferably 2% by mass to 15% by mass relative to the porous magnetic particles. If the amount is small, the internal voids are completely filled with resin, even if only a portion of the internal voids is filled with resin, or even if only the voids near the surface of the porous magnetic particles are filled with resin and voids remain inside. It may be filled.

[filler]
The method of filling the pores of the porous magnetic particles with a resin is not particularly limited, but includes a method of impregnating the porous magnetic particles with a resin solution by a coating method such as a dipping method, a spraying method, a brush coating method, and a fluidized bed, and then volatilizing the solvent. As a method of filling the pores of the porous magnetic particles with a resin, a method of diluting the resin in a solvent and adding this to the pores of the porous magnetic particles can also be used.
The solvent used here may be any solvent capable of dissolving the resin. In the case of a resin soluble in an organic solvent, examples of the organic solvent include toluene, xylene, cellosolve butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and methanol. In the case of a water-soluble resin or an emulsion-type resin, water may be used as the solvent.

The amount of resin solids in the resin solution is preferably 1% to 50% by mass, and more preferably 1% to 30% by mass. If the amount of resin solids is 50% by mass or less, the viscosity of the resin solution is low, so the resin solution is likely to penetrate uniformly into the voids of the porous magnetic particles. If the amount is 1% by mass or more, the amount of resin is large, and the adhesion of the resin to the porous magnetic particles is further increased.

The resin to be filled into the voids of the porous magnetic particles may be either a thermoplastic resin or a thermosetting resin. It is preferable that the resin has a high affinity for the porous magnetic particles. When a resin with a high affinity is used, the surface of the porous magnetic particles can be covered with the resin at the same time as the resin is filled into the voids of the porous magnetic particles.
Examples of the thermoplastic resin to be filled include the following: novolac resin, saturated alkyl polyester resin, polyarylate, polyamide resin, acrylic resin, and the like.
Examples of the thermosetting resin include phenolic resins, epoxy resins, unsaturated polyester resins, and silicone resins.
For example, a silane coupling agent such as γ-aminopropyltrimethoxysilane may be mixed into the silicone resin.

The magnetic carrier is obtained by coating the surfaces of the magnetic core particles with a resin to form a resin coating layer.
The method for coating the surface of the magnetic core particles with a resin is not particularly limited, but examples thereof include coating methods using a coating method such as a dipping method, a spraying method, a brush coating method, a dry method, and a fluidized bed method.

[Compounds containing an amino group]
The compound having an amino group is not particularly limited, but is preferably a silane coupling agent (a reaction product of a silane coupling agent).
For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, 3-(2-aminoethylamino)propyldimethoxymethylsilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyltriethoxysilane, trimethoxy[
At least one selected from the group consisting of N-phenyl-3-aminopropyl]silane, trimethoxy[3-(methylamino)propyl]silane, [3-(N,N-dimethylamino)propyl]trimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and N-2-(aminoethyl)-3-aminopropyltriethoxysilane may be mentioned.

It is preferable that the compound having an amino group is reacted with and fixed to the surface of the magnetic core particles, thereby obtaining a magnetic carrier that is stable for a longer period of time.
Examples of a method for reacting and fixing a compound having an amino group to the surface portion of the magnetic core particles include a method in which the magnetic core particles and the compound having an amino group are stirred while being heated.

Next, a preferred toner configuration will be described in detail below.
The toner preferably contains toner particles and inorganic fine particles.
The toner particles preferably contain a binder resin, a colorant, and a release agent. Examples of the binder resin include vinyl resin, polyester resin, and epoxy resin. Among them, vinyl resin and polyester resin are more preferable in terms of electrostatic chargeability and fixability. Polyester resin is particularly preferable.
Homopolymers or copolymers of vinyl monomers, polyesters, polyurethanes, epoxy resins, polyvinyl butyral, rosin, modified rosin, terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, and the like can be mixed with the binder resins described above as necessary.
When two or more kinds of resins are mixed and used as the binder resin, it is more preferable to mix resins having different molecular weights in an appropriate ratio.

The glass transition temperature (Tg) of the binder resin is preferably 45°C to 80°C, and more preferably 55°C to 70°C. The number average molecular weight (Mn) is preferably 2,500 to 50,000, and the weight average molecular weight (Mw) is preferably 10,000 to 1,000,000.

[Amorphous polyester]
As the binder resin, the following polyester resin is preferred.
Based on all monomer units constituting the polyester resin, it is preferable that 45 mol % to 55 mol % is an alcohol component and 45 mol % to 55 mol % is an acid component.
The acid value of the polyester resin is preferably 90 mgKOH/g or less, more preferably 50 mgKOH/g or less, and the hydroxyl value is preferably 50 mgKOH/g or less, more preferably 30 mgKOH/g or less, because an increase in the number of terminal groups of the molecular chain increases the environmental dependency of the charging characteristics of the toner.
The polyester resin preferably has a glass transition temperature (Tg) of 50° C. to 75° C., more preferably 55° C. to 65° C. The number average molecular weight (Mn) is preferably 1,500 to 50,000, more preferably 2,000 to 20,000. The weight average molecular weight (Mw) is preferably 6,000 to 100,000, more preferably 10,000 to 90,000.

[Crystalline polyester]
For the purpose of promoting the plasticizing effect of the toner and improving the low-temperature fixing property, the following crystalline polyester resin may be added to the toner.
An example of the crystalline polyester is a polycondensate of a monomer composition containing, as main components, an aliphatic diol having 2 to 22 carbon atoms and an aliphatic dicarboxylic acid having 2 to 22 carbon atoms. Here, the main component means that the content thereof is 50% by mass or more.
The aliphatic diol having 2 to 22 carbon atoms (more preferably 6 to 12 carbon atoms) is not particularly limited, but is preferably a chain (more preferably a straight-chain) aliphatic diol. Among these, particularly preferred examples include straight-chain aliphatic α,ω-diols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol.
Of the alcohol components, preferably 50% by mass or more, more preferably 70% by mass or more, is an alcohol selected from aliphatic diols having 2 to 22 carbon atoms.
Polyhydric alcohol monomers other than aliphatic diols can also be used. Among the polyhydric alcohol monomers, examples of dihydric alcohol monomers include aromatic alcohols such as polyoxyethylenated bisphenol A and polyoxypropylenated bisphenol A; 1,4-cyclohexanedimethanol, and the like.
Examples of the trihydric or higher polyhydric alcohol monomer include aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; and aliphatic alcohols such as pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, and trimethylolpropane.
Furthermore, monohydric alcohol may be used to the extent that the properties of the crystalline polyester are not impaired.

On the other hand, the aliphatic dicarboxylic acid having 2 to 22 carbon atoms (more preferably 6 to 12 carbon atoms) is not particularly limited, but is preferably a chain (more preferably linear) aliphatic dicarboxylic acid. Also included are those obtained by hydrolyzing the acid anhydrides or lower alkyl esters of these.
Of the carboxylic acid components, preferably 50% by mass or more, more preferably 70% by mass or more, is a carboxylic acid selected from aliphatic dicarboxylic acids having 2 to 22 carbon atoms.
It is also possible to use polyvalent carboxylic acids other than the above-mentioned aliphatic dicarboxylic acids having 2 to 22 carbon atoms. Among the other polyvalent carboxylic acid monomers, examples of divalent carboxylic acids include aromatic carboxylic acids such as isophthalic acid and terephthalic acid, aliphatic carboxylic acids such as n-dodecylsuccinic acid and n-dodecenylsuccinic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, as well as their acid anhydrides and lower alkyl esters.
Examples of trivalent or higher polyvalent carboxylic acids include aromatic carboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and pyromellitic acid, and aliphatic carboxylic acids such as 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, and 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, and also include derivatives such as acid anhydrides and lower alkyl esters of these.
Furthermore, the crystalline polyester may contain a monovalent carboxylic acid to the extent that the characteristics of the crystalline polyester are not impaired.

The crystalline polyester can be produced according to a conventional polyester synthesis method. For example, the carboxylic acid monomer and the alcohol monomer are subjected to an esterification reaction or an ester exchange reaction, and then the desired crystalline polyester can be obtained by a conventional polycondensation reaction under reduced pressure or by introducing nitrogen gas.
The amount of the crystalline polyester used is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or more, and even more preferably 1 part by mass or more and 15 parts by mass or less, based on 100 parts by mass of the binder resin.

[Inorganic fine particles]
Examples of inorganic fine particles include silica fine particles, alumina fine particles, titania fine particles, and composite oxide fine particles thereof. The inorganic fine particles are preferably negatively chargeable.
The content of the inorganic fine particles is preferably 0.05 parts by mass or more and 5.00 parts by mass or less with respect to 100 parts by mass of the toner particles.
The adhesion rate of the inorganic fine particles to the toner particles is preferably 80.0% or more and 95.0% or less, and more preferably 83.0% or more and 90.0% or less. The adhesion rate of the inorganic fine particles can be controlled by a method such as changing the rotation speed when coating the toner particles with a mixer or the like.

[Coloring agent]
Examples of non-magnetic colorants include the following:
Examples of black colorants include carbon black, and black colorants prepared by using a yellow colorant, a magenta colorant, and a cyan colorant.
Examples of color pigments for magenta toner include the following: condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.Specific examples include C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57, and the like. : 1, 58, 60, 63, 64, 68, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, 269; C.I. Pigment Violet 19, C.I. Bat Red 1, 2, 10, 13, 15, 23, 29, 35, and the like.

As the colorant, a pigment may be used alone, but a dye and a pigment may be used in combination to improve the color clarity.
Dyes for magenta toner include the following: C.I Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, C.I. Disperse Red 9, C.I. Solvent Violet 8, 13, 14, 21, 27, C.I. Disperse Violet 1 and other oil-soluble dyes, C.I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, C.I. Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28 and other basic dyes.
Examples of color pigments for cyan toner include C.I. Pigment Blue 1, 2, 3, 7, 15:2, 15:3, 15:4, 16, 17, 60, 62, 66; C.I. Bat Blue 6, C.I. Acid Blue 45, copper phthalocyanine pigments having 1 to 5 phthalimidomethyl groups substituted on the phthalocyanine skeleton, and the like.
Examples of yellow color pigments include the following: condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal compounds, methine compounds, and allylamide compounds.Specific examples include C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 155, 168, 174, 180, 181, 185, and 191; C.I. Bat Yellow 1, 3, and 20.In addition, dyes such as C.I. Direct Green 6, C.I. Basic Green 4, C.I. Basic Green 6, and Solvent Yellow 162 can also be used.
The amount of the colorant used is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 3 parts by mass or more and 15 parts by mass or less, based on 100 parts by mass of the binder resin.

In addition, in the above toner, it is preferable to use a toner in which a colorant is mixed in advance with a binder resin to form a master batch. Then, by melting and kneading this colorant master batch with other raw materials (binder resin, wax, etc.), the colorant can be well dispersed in the toner.

[Charge control agent]
In order to further stabilize the chargeability of the toner, a charge control agent can be used as necessary. The charge control agent is preferably used in an amount of 0.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the binder resin. When the amount is 0.5 parts by mass or more, the chargeability becomes better. When the amount is 10 parts by mass or less, the compatibility with other materials becomes good and the charge amount under low humidity can be made more appropriate.

Examples of the charge control agent include the following.
As a negative charge control agent for controlling the toner to be negatively charged, for example, an organic metal complex or a chelate compound is effective. Examples of the negative charge control agent include monoazo metal complexes, metal complexes of aromatic hydroxycarboxylic acids, and metal complexes of aromatic dicarboxylic acids. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, their anhydrides, or their esters, or phenol derivatives of bisphenol.
Examples of positive charge control agents that control the toner to be positively charged include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts that are analogs of these, and chelate pigments thereof such as triphenylmethane dyes and lake pigments thereof (lake forming agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstomolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide compounds, etc.), and metal salts of higher fatty acids such as diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, and dicyclohexyltin oxide, and diorganotin borates such as dibutyltin borate, dioctyltin borate, and dicyclohexyltin borate.

[Release agent]
If necessary, one or more kinds of releasing agents may be contained in the toner particles. Examples of the releasing agents include the following.
Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax can be preferably used. In addition, examples include oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof; waxes mainly composed of fatty acid esters such as carnauba wax, sazol wax, and montan acid ester wax; and partially or completely deoxidized fatty acid esters such as deoxidized carnauba wax.
The amount of the release agent is preferably 0.1 parts by mass or more and 20 parts by mass or less, and more preferably 0.5 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the binder resin.
The melting point of the release agent, which is defined as the maximum endothermic peak temperature during heating measured by a differential scanning calorimeter (DSC), is preferably 65°C to 130°C. More preferably, it is 80°C to 125°C. If the melting point is 65°C or higher, the viscosity of the toner falls within an appropriate range, and toner adhesion to the photoreceptor is unlikely to occur. If the melting point is 130°C or lower, low-temperature fixability is good.

[Resin composition]
The toner particles preferably contain a resin composition in which an aliphatic hydrocarbon compound and a vinyl resin component are bonded together.
The resin composition in which an aliphatic hydrocarbon compound is bonded to a vinyl-based resin component is a resin composition containing a graft polymer having a structure in which a polyolefin is grafted to a vinyl-based resin component, or a graft polymer having a vinyl-based resin component in which a vinyl-based monomer is graft polymerized to a polyolefin.
When the toner particles contain the resin composition, the release agent acts as a driving force when the surface is treated with hot air using the surface treatment device shown in Fig. 1, and the resin composition is oriented on the surface of the toner particles. The resin composition usually has a higher glass transition temperature Tg than the binder resin, and therefore can form a core-shell structure with a hard shell. Therefore, the non-electrostatic adhesion can be suppressed to a low level, resulting in excellent developability and anti-fogging properties.
In addition, it is more preferable that the vinyl resin component has a monomer unit derived from cycloalkyl (meth)acrylate from the viewpoint of developing property and suppressing fogging. When the vinyl resin component has the monomer unit, the hydrophobicity of the toner is increased and the amount of moisture adsorbed in a high-temperature and high-humidity environment is reduced. As a result, the charge rise property is improved.
From the viewpoint of suppressing fogging, it is preferable to perform surface treatment of the toner particles with hot air using, for example, a surface treatment device shown in Fig. 1. By using the surface treatment device shown in Fig. 1, the toner particles are subjected to hot air treatment in a hydrophobic field in the air, so that the release agent, which is a constituent material of the toner, migrates to the vicinity of the surface of the toner particles. As a result, the hydrophobicity of the toner particle surface is increased, the amount of moisture adsorption in a high-temperature and high-humidity environment is reduced, and the non-electrostatic adhesion force can be suppressed to a low level, thereby obtaining excellent developability and fogging properties.

The mixture supplied by the material supply means 1 is introduced into an introduction pipe 3, which is installed vertically to the material supply means, by compressed gas adjusted by a compressed gas adjustment means 2. The mixture passing through the introduction pipe is uniformly dispersed by a conical protruding member 4 provided in the center of the material supply means, and is introduced into eight supply pipes 5 that radiate outward, and then into a treatment chamber 6 where heat treatment is carried out.
At this time, the flow of the mixture supplied to the treatment chamber is regulated by a regulating means 9 for regulating the flow of the mixture provided in the treatment chamber, so that the mixture supplied to the treatment chamber is heat-treated while swirling in the treatment chamber, and then cooled.

The heat for heat-treating the supplied mixture is supplied from the hot air supplying means 7, distributed by the distribution member 12, and introduced into the treatment chamber by the swirling member 13 for swirling the hot air in a spiral shape. The swirling member 13 for swirling the hot air has multiple blades, and the swirling of the hot air can be controlled by the number and angle of the blades. The hot air supplied into the treatment chamber preferably has a temperature of 100°C to 300°C at the outlet of the hot air supplying means 7, and more preferably 130°C to 250°C. If the temperature at the outlet of the hot air supplying means is within the above range, it is possible to uniformly spheronize the toner particles while preventing the toner particles from fusing or coalescing due to excessive heating of the mixture. The hot air is supplied from the hot air supplying means outlet 11.

The heat-treated toner particles are then cooled by cold air supplied from cold air supply means 8, and the temperature of the cold air supplied from cold air supply means 8 is preferably -20°C to 30°C. If the temperature of the cold air is within the above range, the heat-treated toner particles can be efficiently cooled, and the fusion and coalescence of the heat-treated toner particles can be prevented without impeding the uniform spheroidization of the mixture. The absolute moisture content of the cold air is preferably 0.5 g/ ^m3 or more and 15.0 g/ ^m3 or less.
Next, the cooled heat-treated toner particles are collected by the collecting means 10 at the bottom end of the processing chamber. A blower (not shown) is provided ahead of the collecting means, and the toner particles are sucked and transported by the blower.

The powder particle supply port 14 is provided so that the swirling direction of the supplied mixture and the swirling direction of the hot air are the same, and the recovery means 10 of the surface treatment device is provided on the outer periphery of the treatment chamber so as to maintain the swirling direction of the swirled powder particles. Furthermore, the cold air supplied from the cold air supply means 8 is configured to be supplied horizontally and tangentially from the outer periphery of the device to the circumferential surface inside the treatment chamber. The swirling directions of the pre-heat-treated toner particles supplied from the powder supply port, the swirling direction of the cold air supplied from the cold air supply means, and the swirling direction of the hot air supplied from the hot air supply means are all the same. Therefore, no turbulence occurs in the treatment chamber, the swirling flow in the device is strengthened, a strong centrifugal force is applied to the pre-heat-treated toner particles, and the dispersibility of the pre-heat-treated toner particles is further improved, so that heat-treated toner particles with a uniform shape and few coalesced particles can be obtained.

The aliphatic hydrocarbon compound is not particularly limited as long as it is a polymer or copolymer of an unsaturated hydrocarbon monomer having one double bond, and various polyolefins can be used. In particular, polyethylene-based and polypropylene-based compounds are preferably used.

Examples of vinyl monomers used in the vinyl resin component include the following: styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, and p-n-dodecylstyrene, and derivatives thereof; amino group-containing α-methylene aliphatic monocarboxylic acid esters such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; and vinyl monomers containing an N atom such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.
Unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenylsuccinic acid, fumaric acid, and mesaconic acid; unsaturated dibasic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, and alkenylsuccinic anhydride; methyl maleate half ester, ethyl maleate half ester, butyl maleate half ester, methyl citraconic acid half ester, ethyl citraconic acid half ester, butyl citraconic acid half ester, methyl itaconic acid half ester, methyl alkenylsuccinic acid half ester, and fumaric acid unsaturated dibasic acid esters such as dimethyl maleic acid and dimethyl fumaric acid; α,β-unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid and cinnamic acid; α,β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic acid anhydride, anhydrides of the above α,β-unsaturated acids and lower fatty acids; vinyl monomers containing a carboxyl group, such as alkenyl malonic acid, alkenyl glutaric acid, alkenyl adipic acid, acid anhydrides thereof, and monoesters thereof.
Acrylic or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; and vinyl monomers containing a hydroxyl group such as 4-(1-hydroxy-1-methylbutyl)styrene and 4-(1-hydroxy-1-methylhexyl)styrene.

Ester units consisting of acrylate esters such as acrylate esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate.
Ester units consisting of methacrylic acid esters such as α-methylene aliphatic monocarboxylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate.

During melt kneading, the resin composition is compounded with the wax and crystalline polyester resin via the resin composition, and the viscosity of the kneading system can be controlled. Therefore, even when melt kneading is performed in the presence of crystalline polyester resin, which is disadvantageous for material dispersion, material dispersion can be improved and image quality can be improved. In particular, when the vinyl resin component has a structure derived from cyclohexyl (meth)acrylate, compounding due to interaction with the crystalline polyester resin is promoted, improving material dispersion and coloring power, which is more preferable.

The resin composition in which an aliphatic hydrocarbon compound and a vinyl resin component are bonded together can be obtained by a known method, such as the reaction between these vinyl monomers described above, or the reaction between a monomer of one polymer and a monomer of the other polymer.
The vinyl resin component preferably contains a styrene unit, an ester unit, acrylonitrile, or methacrylonitrile as a constituent unit. The resin composition preferably has a glass transition temperature (Tg) of 50° C. or more and 100° C. or less in order to achieve both storage stability, low-temperature fixability, and high-temperature offset resistance.
In addition, the resin composition in which the aliphatic hydrocarbon compound and the vinyl resin component are bonded has the effect of increasing the affinity between the molten binder resin and the wax in the kneading step during toner production, and therefore, by incorporating the resin composition in the toner, the dispersibility of the wax in the toner particles can be controlled, which is preferable.
Furthermore, when performing surface treatment using heat, coalescence of toner particles becomes an issue, but it has been confirmed that this is a rare material that can prevent coalescence.

The mass ratio of the aliphatic hydrocarbon compound to the vinyl resin component in the resin composition is preferably 1/99 or more and 75/25 or less, more preferably 10/90 or more and 50/50 or less. The content of the resin composition in which the aliphatic hydrocarbon compound and the vinyl resin component are combined is preferably equal to or more than the amount of the crystalline polyester resin added, in order to maintain the above-mentioned composite state.
The content of the resin composition is preferably 0.2 parts by mass or more and 40.0 parts by mass or less, more preferably 1.0 parts by mass or more and 20.0 parts by mass or less, based on 100 parts by mass of the binder resin.

[Flow improver]
The toner may contain a fine powder as a flowability improver, which can improve the flowability of the toner by adding it to the outside of the toner particles.
Examples of the flow improver include fluororesin powders such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder, fine silica powders such as wet-processed silica and dry-processed silica, fine titanium oxide powder, fine strontium titanate powder, fine alumina powder, and the like, which have been surface-treated with a silane coupling agent, a titanium coupling agent, or silicone oil to impart hydrophobicity, and particularly preferred are those treated so that the hydrophobicity degree measured by a methanol titration test falls within the range of 30 to 80.
The content of the flowability improver is preferably 0.1 to 10 parts by mass, and more preferably 0.2 to 8 parts by mass, based on 100 parts by mass of the toner particles.

[Toner charge amount]
The charge amount of the toner, which is determined according to the measurement method of triboelectric charge amount described later using a standard carrier for negatively charged toner, is preferably −200 mC/kg or more and −20 mC/kg or less.

[Calculation of Toner Charge Amount]
The charge amount of the toner is calculated as follows.
The measurement environment is a temperature of 23° C. and a relative humidity of 50%, and a standard carrier for negatively charged toner (manufactured by Nippon Imaging Co., Ltd.) is used as the carrier. A mixture of 9.0 g of carrier and 1.0 g of toner whose chargeability is to be measured is placed in a 50 ml polyethylene bottle and allowed to stand for 12 hours.
Next, the mixture is shaken at 200 rpm for 5 minutes using a Model-YS-LD shaker (manufactured by Yayoi Co., Ltd.) Next, in the frictional charge measurement device shown in Fig. 2, 0.15 g of the mixture is placed in a metal measurement container 22 having a 635 mesh screen 23 at the bottom, and the metal lid 24 is placed on the container. The total mass of the measurement container at this time is weighed and taken as W1 (g).
Next, in the suction machine 21 (at least the part in contact with the measurement container 22 is an insulator), suction is performed from the suction port 27, and the air flow control valve 26 is adjusted so that the pressure on the vacuum gauge 25 is 1.5 kPa. Suction is performed for two minutes in this state, and the toner is removed by suction. The potential on the electrometer 29 at this time is V (volts). Here, 28 is a capacitor with a capacity of C (μF). The mass of the entire measuring machine after suction is also weighed and is designated as W2 (g). The triboelectric charge Q (mC/kg) of the sample is calculated by the following formula:
Q=-CV/(W1-W2)

[Charge amount of inorganic fine particles]
The charge amount of the inorganic fine particles is preferably −200 mC/kg or more and −20 mC/kg or less.
The charge amount of the inorganic fine particles is calculated as follows.
The measurement environment was a temperature of 23° C. and a relative humidity of 50%, and a standard carrier for negatively charged toner (manufactured by Nippon Imaging Co., Ltd.) was used as the carrier. A mixture of 9.9 g of carrier and 0.1 g of a sample (inorganic fine particles) for which the chargeability is to be measured was placed in a 50 ml polyethylene bottle and allowed to stand for 12 hours.
Next, the mixture is shaken at 150 rpm for 2 minutes using a Model-YS-LD shaker (manufactured by Yayoi Co., Ltd.) Next, in the frictional charge measurement device shown in Fig. 2, 0.4 g of the mixture is placed in a metal measurement container 22 having a 635 mesh screen 23 at the bottom, and the metal lid 24 is placed on the container. The total mass of the measurement container at this time is weighed and taken as W1 (g).
Next, in the suction machine 21 (at least the part in contact with the measurement container 22 is an insulator), suction is performed from the suction port 27, and the air flow control valve 26 is adjusted so that the pressure on the vacuum gauge 25 is 2 kPa. Suction is performed in this state for one minute, and the inorganic fine particles used as the sample are removed by suction. The potential on the electrometer 29 at this time is V (volts). Here, 28 is a capacitor with a capacity of C (μF). The mass of the entire measuring machine after suction is also weighed and is designated as W2 (g). The triboelectric charge Q (mC/kg) of the sample is calculated from the following formula:
Q=-CV/(W1-W2)

When a magnetic carrier and a toner are mixed to be used as a two-component developer, good results are usually obtained when the mixing ratio of the magnetic carrier is preferably 2% by mass to 15% by mass, more preferably 4% by mass to 13% by mass, in terms of the toner concentration in the developer. When the toner concentration is 2% by mass or more, a decrease in image density is suppressed, and when it is 15% by mass or less, fogging and scattering in the machine are unlikely to occur.
In addition, in a replenishing developer to be replenished to a developing device in response to a decrease in the toner concentration of the two-component developer in the developing device, the amount of toner is 2 to 50 parts by weight per part by weight of the replenishing magnetic carrier.

Next, the measurement methods for each physical property will be described.
<Method for measuring nitrogen atom concentration on magnetic carrier surface>
The nitrogen atom concentration on the magnetic carrier surface is calculated as follows: Elemental analysis of the nitrogen atom concentration is performed using the following apparatus under the following conditions.
Measurement device: X-ray photoelectron spectrometer: Quantum 2000 (product name, manufactured by ULVAC-PHI, Inc.)
X-ray source: Monochrome Al Kα
・Xray Setting: 100μmφ (25W (15KV))
Photoelectron take-off angle: 45 degrees Neutralization conditions: Neutralization gun and ion gun used together Analysis area: 300 x 200 μm
・Pass Energy: 58.70eV
Step size: 0.125 eV
・Analysis software: Maltipak (PHI)
In the surface analysis of the magnetic carrier by XPS, N1s (B.E.eV), C1s (B.E.eV), O1s (B.E.eV), Si2p (B.E.eV), Ti2p (B.E.eV), and Fe2p3 (B.E.eV) are measured. B.E. stands for Binding.
The measured atomic concentration (atomic %) of N1s is defined as the nitrogen atomic concentration.

<Method of measuring 50% particle size (D50) based on volume distribution of magnetic carrier, magnetic core particle, and porous magnetic particle>
The particle size distribution and 50% particle size (D50) based on volume distribution of the magnetic carrier, magnetic core particles, and porous magnetic particles are measured by attaching a sample supplying device for dry measurement, "One-shot dry type sample conditioner Turbotrac" (manufactured by Nikkiso Co., Ltd.), to a laser diffraction/scattering type particle size distribution measuring device, "Microtrac MT3300FX" (manufactured by Nikkiso Co., Ltd.). The supply conditions for Turbotrac are a dust collector used as a vacuum source, an air volume of about 33 L/sec, and a pressure of about 17 kPa. Control is performed automatically on the software. The particle size is calculated as the 50% particle size (D50), which is a cumulative value based on volume. Control and analysis are performed using the attached software (version 10.3.3-202D). The measurement conditions are as follows.
SetZero time: 10 seconds Measurement time: 10 seconds Number of measurements: 1 Particle refractive index: 1.81%
Particle shape: Non-spherical Upper limit of measurement: 1408μm
Measurement lower limit: 0.243μm
Measurement environment: 23℃, 50%RH

<Separation of Resin Coating Layer from Magnetic Carrier and Separation of Coating Resins A and B in the Resin Coating Layer>
The resin coating layer is separated from the magnetic carrier by placing 1.0 g of the magnetic carrier in a cup and eluting the coating resin with 10.0 g of toluene.
The eluted resin is dried and then dissolved in 10.0 g of tetrahydrofuran (THF), and separated using the following apparatus.

[Device configuration]
LC-908 (Japan Analytical Industry Co., Ltd.)
JRS-86 (same company; repeat injector)
JAR-2 (same company; autosampler)
FC-201 (Gilson; fraction collector)
[Column configuration]
JAIGEL-1H to 5H (20φ×600 mm: preparative column) (manufactured by Japan Analytical Industry Co., Ltd.)
[Measurement condition]
Temperature: 40°C
Solvent: THF
Flow rate: 5mL/min.
Detector: RI

Based on the molecular weight distribution of the coating resin, the resin composition is specified by the following method, and the elution times at which the peak molecular weights (Mp) of coating resin A and coating resin B are reached are measured in advance, and the resin components are separated around that time. The solvent is then removed, and the resin is dried to obtain coating resin A and coating resin B.
The resin structures of coating resin A and coating resin B can be identified by identifying the atomic groups from the absorption wave numbers using a Fourier transform infrared spectrometer (Spectrum One: manufactured by PerkinElmer).

<Measurement of weight average molecular weight (Mw), peak molecular weight (Mp) and content ratio of coating resin A, coating resin B and resin coating layer in resin coating layer>
The weight average molecular weight (Mw) and peak molecular weight (Mp) of the coating resin A, the coating resin B, and the resin coating layer are measured by gel permeation chromatography (GPC) according to the following procedure.

First, a measurement sample is prepared as follows.
The samples (the coating resin separated from the magnetic carrier, the coating resin A and the coating resin B separated by the separation device) are mixed with tetrahydrofuran (THF) at a concentration of 5 mg/mL, and left to stand at room temperature for 24 hours to dissolve the sample in THF. The sample is then passed through a sample treatment filter (Myshoridisk H-25-2, manufactured by Tosoh Corporation) to prepare a GPC sample.
Next, using a GPC measuring device (HLC-8120GPC manufactured by Tosoh Corporation), measurements are carried out under the following measuring conditions according to the operating manual for said device.
(Measurement condition)
Equipment: High-speed GPC “HLC8120 GPC” (manufactured by Tosoh Corporation)
Column: 7 columns of Shodex KF-801, 802, 803, 804, 805, 806, and 807 (manufactured by Showa Denko K.K.)
Eluent: THF
Flow rate: 1.0mL/min
Oven temperature: 40.0°C
Sample injection volume: 0.10 mL

In addition, when calculating the weight average molecular weight (Mw) and peak molecular weight (Mp) of the sample, a molecular weight calibration curve prepared using standard polystyrene resins (TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500 manufactured by Tosoh Corporation) is used.
The content ratio is determined from the peak area ratio in the molecular weight distribution measurement. When region 1 and region 2 are completely separated as in Fig. 3, the resin content ratio is determined from the area ratio of each region. When the regions overlap as in Fig. 4, they are divided by a line drawn vertically from the inflection point of the GPC molecular weight distribution curve to the horizontal axis, and the content ratio is determined from the area ratio of region 1 and region 2 shown in Fig. 4.

<Method of measuring weight average particle size (D4) of toner particles>
The weight average particle diameter (D4) of the toner particles is measured using a precision particle size distribution measuring device using a pore electrical resistance method equipped with a 100 μm aperture tube, "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.), and the accompanying dedicated software for setting measurement conditions and analyzing measurement data, "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). Measurement is performed with an effective measurement channel count of 25,000 channels, and the measurement data is analyzed and calculated.
The aqueous electrolyte solution used for the measurement is "ISOTON II" (manufactured by Beckman Coulter, Inc.), which is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of about 1 mass %.
Before performing the measurements and analysis, the dedicated software was set up as follows.
In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count number in the control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter). Press the threshold/noise level measurement button to automatically set the threshold and noise level. In addition, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the aperture tube flush after measurement.
In the "Pulse to particle size conversion setting screen" of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bins, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) Pour about 200 mL of the electrolyte solution into a 250 mL round-bottom glass beaker for use with the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 rotations per second. Then, remove dirt and air bubbles from inside the aperture tube using the "aperture tube flush" function of the dedicated software.
(2) About 30 mL of the aqueous electrolyte solution is placed in a 100 mL flat-bottom glass beaker, and about 0.3 mL of a dilution obtained by diluting "Contaminon N" (a 10% aqueous solution of a neutral detergent for cleaning precision measuring instruments, pH 7, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with ion-exchanged water is added thereto as a dispersant.
(3) A predetermined amount of ion-exchanged water is placed in the water tank of an ultrasonic disperser "Ultrasonic Dispersion System Tetora 150" (manufactured by Nikkaki Bios Co., Ltd.) that has two built-in oscillators with an oscillation frequency of 50 kHz and a phase shift of 180 degrees and an electric output of 120 W. About 2 mL of the above-mentioned Contaminon N is added to this water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized.
(5) In a state where the electrolyte solution in the beaker in (4) is irradiated with ultrasonic waves, about 10 mg of toner particles are added little by little to the electrolyte solution and dispersed. Then, ultrasonic dispersion treatment is continued for another 60 seconds. During ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be 10°C to 40°C.
(6) Using a pipette, the electrolyte solution (5) in which the toner particles are dispersed is dropped into the round-bottom beaker (1) placed in the sample stand, and the measurement concentration is adjusted to about 5%. Then, the measurement is continued until the number of particles measured reaches 50,000.
(7) The measurement data is analyzed using the dedicated software that comes with the device, and the weight-average particle size (D4) is calculated. Note that when the dedicated software is set to Graph/Volume %, the "Average diameter" on the Analysis/Volume Statistics (Arithmetic Mean) screen is the weight-average particle size (D4).

<Method of measuring diameter of Lu, closest distance between Lu, and Ar>
The diameter of Lu, the closest distance between Lu, and Ar can be obtained by the following method.
Lu is a portion of a reflected electron image of a magnetic carrier photographed by a scanning electron microscope at an accelerating voltage of 2.0 kV, in which the reflected electron image is obtained as an 8-bit, 256-level grayscale image, with a luminance range of 140 to 255. Ar is the ratio of the total area of Lu to the total projected area of the magnetic carrier.
The diameter of Lu, the closest distance between Lu particles, and Ar are measured using a scanning electron microscope (SEM) S-4800 (manufactured by Hitachi, Ltd.).
Specifically, the carrier particles are fixed in a single layer on a sample stage for electron microscope observation with carbon tape. Without platinum deposition, the sample is observed under the following conditions with a scanning electron microscope S-4800 (manufactured by Hitachi, Ltd.). Observation is performed after a flushing operation.
SignalName=SE(U, LA80)
AcceleratingVoltage=2000Volt
Emission Current=10000nA
Working Distance=6000um
LensMode=High
Condenser1=5
ScanSpeed = Slow4 (40 seconds)
Magnification=600
DataSize=1280×960
ColorMode=Grayscale

The backscattered electron image is adjusted to 'contrast 5, brightness -5' on the control software of the scanning electron microscope S-4800, and the capture speed/accumulation number is set to 'Slow 4 for 40 seconds', and a projection image of the magnetic carrier is obtained as an 8-bit 256-level grayscale image with an image size of 1280 x 960 pixels. From the scale on the image, the length of 1 pixel is 0.1667 μm, and the area of 1 pixel is ^0.0278 μm2.
Using the obtained projected image by the reflected electrons, the area ratio (area %) of the portion without the resin coating layer is calculated for 100 magnetic carriers. The portion without the resin coating layer has high brightness due to the influence of the metal oxide of the magnetic core particle. In other words, it is considered that the portion with high brightness is the portion where the compound having an amino group is exposed. The method of selecting 100 magnetic carriers to be analyzed will be described in detail later. The area % of the portion without the resin coating layer is calculated using image processing software Image-Pro Plus5.1J (manufactured by MediaCybernetics).

First, the size of the magnetic carrier is measured. Specifically, in order to extract the magnetic carrier to be analyzed, the magnetic carrier is separated from the background. Select "Measurement" - "Count/Size" in Image-Pro Plus 5.1J. In "Count/Size" - "Brightness Range Selection", the brightness range was set to 50 to 255, and the carbon tape part with low brightness that was reflected in the background was excluded, and the magnetic carrier was extracted.
When the magnetic carrier is fixed by a method other than carbon tape, the background may not necessarily have a low brightness area, or may partially have the same brightness as the magnetic carrier. However, the boundary between the magnetic carrier and the background can be easily distinguished from the backscattered electron observation image.
When extracting, select 4-connected in the "Count/Size" extraction options, enter a smoothness of 5, check "Fill holes," and exclude from the calculation any particles that are located on the boundaries (outer periphery) of the image or that overlap with other particles. In the "Count/Size" measurement items, select area and Feret's diameter (average), and set the area selection range to a minimum of 300 pixels and a maximum of 10,000,000 pixels.
The selection range is set so that the Feret diameter (average) is within ±25% of the measured value of the volume distribution standard 50% particle diameter (D50) of the magnetic carrier described later, and the magnetic carrier to be image analyzed is extracted. One particle is selected from the extracted particle group, and the size (number of pixels) and the total projected area (ja) of the magnetic carrier are obtained.

Next, in "Count/Size" of Image-Pro Plus 5.1J, "Brightness Range Selection" is set to a brightness range of 140 to 255, and high brightness portions on the magnetic carrier are extracted. The selection range of the area is set to a minimum of 10 pixels and a maximum of 10,000 pixels.
The parts without the resin coating layer are scattered as domains. The diameter (μm) and area (number of pixels) are calculated for each domain in one particle. Here, the diameter is the equivalent circle diameter. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image. The total area of the domains (i.e., the total area of Lu) is ma. Ar is calculated by (ma/ja)×100. In addition, the shortest distance between adjacent domains (the closest distance between Lu (μm)) is calculated.
The same process is carried out for each extracted particle until the number of selected magnetic carriers reaches 100. If the number of particles in one visual field is less than 100, the same operation is repeated for the magnetic carrier projected image in another visual field. For the 100 particles, the diameter of Lu, the closest distance between Lu particles, and Ar are calculated, and the arithmetic average value is taken as the value of each parameter.

<Measurement of cumulative pore volume and average pore diameter of porous magnetic particles>
The cumulative pore volume of the porous magnetic particles is measured by mercury intrusion porosimetry. The measurement principle is as follows.
In this measurement, the pressure applied to the mercury is changed and the amount of mercury that penetrates into the pores is measured. The condition under which mercury can penetrate into the pores can be expressed as PD = -4σ cos θ from the balance of forces, where P is the pressure, D is the pore diameter, θ is the contact angle of mercury, and σ is the surface tension.
If the contact angle and surface tension are constants, then the pressure P is inversely proportional to the pore diameter D into which mercury can penetrate at that time. For this reason, the pressure P and the amount of liquid that penetrates at that time V are measured while changing the pressure, and the horizontal axis P of the P-V curve obtained is directly substituted into the pore diameter in this formula to obtain the pore distribution, and the differential pore volume in the pore diameter range of 0.1 μm to 3.0 μm is integrated to calculate the pore volume (intermediate coating part in FIG. 5(b)).
The measurement is performed using an Autopore IV9520 from Shimadzu Corporation under the following conditions and procedures.

(Measurement condition)
Measurement environment: 20°C
Measurement cell: sample volume ⁵ cm3
Pressurization volume: 1.1 ^cm3 Application: Powder Measurement range: 2.0 psia (13.8 kPa) or more and 59989.6 psia (413.7 MPa) or less Measurement steps: 80 steps (steps are set so that the pore diameter is evenly spaced when taken logarithmically)
Pressurized volume: Adjusted to 25% or more and 70% or less Low pressure parameters: Exhaust pressure: 50 μmHg
Exhaust time: 5.0 min
Mercury injection pressure: 2.0 psia (13.8 kPa)
Equilibrium time: 5secs
High pressure parameters: Equilibration time: 5 sec
Mercury parameters: Advancing contact angle: 130.0 degrees
Receding contact angle: 130.0 degrees
Surface tension: 485.0mN/m (485.0dynes/cm)
Mercury density: 13.5335g/mL

(Measurement procedure)
(1) Approximately 1.0 g of porous magnetic particles is weighed and placed in the sample cell.
Then, the weighing value is input.
(2) In the low pressure section, the pressure is measured in the range of 2.0 psia (13.8 kPa) to 45.8 psia (315.6 kPa).
(3) In the high pressure section, the pressure range is measured to be 45.9 psia (316.3 kPa) or more and 59,989.6 psia (413.6 MPa) or less.
(4) Calculate the pore distribution and average pore diameter from the mercury injection pressure and the amount of mercury injected. Here, the average pore diameter is a value calculated by analysis using the attached software, and is the value of the median pore diameter (volume basis) when the pore diameter is specified to be in the range of 0.1 μm to 3.0 μm.
Steps (2), (3), and (4) are performed automatically by the software provided with the device.

An example of the pore distribution measured as described above is shown in Figure 5. Figure 5(a) shows the entire measurement range of the pore distribution of the porous magnetic particles, and Figure 5(b) shows a diagram of a portion of the pore distribution of the porous magnetic particles in the pore diameter range of 0.1 μm to 6.0 μm.
The cumulative pore volume in the pore diameter range of 0.1 μm to 3.0 μm is calculated by integrating the log differential pore volume in the pore diameter range of 0.1 μm to 3.0 μm using the attached software. Furthermore, the average pore diameter is also calculated.
In Fig. 5(b), the pore volume in the pore diameter range of 0.1 μm to 3.0 μm is shown in black. Fig. 5(c) shows a cut-out portion of the pore diameter range of 0.1 μm to 6.0 μm in the pore diameter distribution of the resin-filled porous magnetic particles. In Fig. 5(c), the pore volume in the pore diameter range of 0.1 μm to 3.0 μm is shown in black.

<Measurement of adhesion rate of inorganic fine particles>
The fixed inorganic fine particles are defined as follows: 20 g of ion-exchanged water and 0.4 g of a surfactant, Contaminon N (a 10% by weight aqueous solution of a neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, having a pH of 7, manufactured by Wako Pure Chemical Industries, Ltd.) are placed in a 30 mL glass vial (for example, VCV-30 manufactured by Nichiden Rika Glass Co., Ltd., outer diameter: 35 mm, height: 70 mm) and mixed thoroughly to prepare a dispersion.
1.0 g of toner is added to this vial, and the toner is left to stand until it naturally settles to prepare a pre-treatment dispersion. This dispersion is shaken for 5 minutes at a shaking speed of 46.7 cm/sec and a shaking width of 4.0 cm. Inorganic fine particles that do not come off even after shaking are considered to be fixed. A centrifuge is used to separate the toner with the inorganic fine particles remaining from the detached inorganic fine particles. The centrifugation process is performed at 3700 rpm for 30 minutes. The toner with the inorganic fine particles remaining is collected and dried to obtain the toner after the separation process.
The adhesion rate is measured as follows. First, the amount of inorganic fine particles contained in the toner before the separation process is quantified. This is done by measuring the elemental strength of the inorganic fine particles in the toner using a wavelength dispersive X-ray fluorescence analyzer Axios advanced (manufactured by PANalytical Corporation). Next, the elemental strength of the inorganic fine particles in the toner after the separation process is measured in the same manner. The adhesion rate is calculated using the following formula.
Adhesion rate=(element strength of inorganic fine particles in toner after separation process/element strength of inorganic fine particles in toner)×100(%)

The measurement of the fluorescent X-rays of each element conforms to JIS K 0119-1969, and specifically, is as follows.
The measurement equipment used is a wavelength dispersive X-ray fluorescence analyzer "Axios" (manufactured by PANalytical) and the accompanying dedicated software "SuperQver. 4.0F" (manufactured by PANalytical) for setting measurement conditions and analyzing measurement data. Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 10 mm, and the measurement time is 10 seconds. In addition, when measuring light elements, a proportional counter (PC) is used for detection, and when measuring heavy elements, a scintillation counter (SC) is used for detection.
As a measurement sample, about 1 g of toner after the separation process or toner before the separation process is placed in a dedicated aluminum ring for pressing with a diameter of 10 mm, flattened, and pressed at 20 MPa for 60 seconds using a tablet molding compression machine "BRE-32" (manufactured by Maekawa Test Machinery Manufacturing Co., Ltd.) to form a pellet with a thickness of about 2 mm.
Measurement is performed under the above conditions, and the elements are identified based on the peak positions of the obtained X-rays, and their concentrations are calculated from the counting rate (unit: cps), which is the number of X-ray photons per unit time.

The amount of silicon in the toner can be determined by adding 0.5 parts by mass of silica ( _SiO2 ) fine powder to 100 parts by mass of toner particles, and thoroughly mixing the powder using a coffee mill. Similarly, 2.0 parts by mass and 5.0 parts by mass of silica fine powder are mixed with the toner particles, respectively, and these are used as samples for the calibration curve.
For each sample, a pellet of the calibration curve sample is prepared as described above using a tablet molding compression machine, and the count rate (unit: cps) of Si-Kα rays observed at a diffraction angle (2θ) = 109.08 ° when PET is used as the analyzing crystal is measured. At this time, the acceleration voltage and current value of the X-ray generator are 24 kV and 100 mA, respectively. A linear function calibration curve is obtained by taking the obtained X-ray count rate as the vertical axis and the amount of _SiO2 added in each calibration curve sample as the horizontal axis.
Next, the toner to be analyzed is pelletized as described above using a tablet molding compressor, and the count rate of the Si-Kα radiation is measured. The content of the organosilicon polymer in the toner is then determined from the above calibration curve. The ratio of the amount of elements in the toner after washing with water to the amount of elements in the initial toner calculated by the above method is determined and taken as the adhesion rate (%).
When titanium oxide particles and strontium titanate particles are used in addition to silica, the value obtained by measuring Ti may be added to the elemental intensity of Si for calculation. The elements to be measured may be changed depending on the constituent elements of the inorganic fine particles.

<Method of measuring the average grain size of porous magnetic particles>
The sample is a porous magnetic particle. Alternatively, 1.0 g of the magnetic carrier is weighed in a beaker, and the resin coating layer is eluted using 20.0 g of xylene. The magnetic carrier from which the resin coating layer has been eluted can be dried to prepare a sample.
The average grain size is observed under the following conditions using a scanning electron microscope (SEM) S-4800 (manufactured by Hitachi High-Technologies Corporation). Note that the observation is performed after a flushing operation.
SignalName=SE(U, LA100)
Accelerating Voltage=5000 Volt
Emission Current=10000nA
Working Distance=4000um
LensMode=High
Condenser1=3
ScanSpeed=Slow4 (40sec)
Magnification=1500
DataSize=1280x960
ColorMode=Grayscale
SpecimenBias=0V
In addition to the above conditions, the backscattered electron image was captured by adjusting the brightness to "contrast 5, brightness -5" on the control software of the scanning electron microscope S-4800, turning off the magnetic field observation mode, and obtaining a grayscale image with 256 gradations.
The average grain diameter of the porous magnetic particles was calculated by analyzing the obtained grayscale SEM reflected electron image using image analysis software Image-ProPlus5.1J (Media Cy)
The calculation is performed using a FT-IR spectrometer (manufactured by Bernetics) according to the following procedure.
First, the porous magnetic particles to be used as samples are those having a maximum diameter of each sample of Dmax, and D50 x 0.9 ≦ Dmax ≦ D50 x 1.1. Furthermore, the horizontal Feret diameter of the grain to be measured is measured in the SEM backscattered electron image of the porous magnetic particles. Furthermore, the same measurement is performed on 20 porous magnetic particles, and the arithmetic average value is used.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Note that the number of parts in the examples and comparative examples is based on mass unless otherwise specified.

<Production Example of Porous Magnetic Particle 1 and Magnetic Core Particle 1>
Process 1 (weighing and mixing process)
Fe ₂ O ₃ 68.3% by mass
MnCO ₃ 28.5% by mass
Mg(OH) ₂ 2.0% by mass
SrCO ₃ 1.2% by mass
The above ferrite raw materials were weighed, 80 parts of the ferrite raw materials were mixed with 20 parts of water, and then wet-mixed in a ball mill with zirconia having a diameter (φ) of 10 mm for 3 hours to prepare a slurry. The solid content of the slurry was 80 mass %.
Step 2 (pre-firing step)
The mixed slurry was dried using a spray dryer (manufactured by Okawara Kakoki Co., Ltd.) and then fired in a batch-type electric furnace in a nitrogen atmosphere (oxygen concentration: 1.0% by volume) at a temperature of 1,050° C. for 3.0 hours to produce calcined ferrite.
Step 3 (Crushing step)
The calcined ferrite was crushed to about 0.5 mm with a crusher, and water was added to prepare a slurry. The solid content of the slurry was set to 70 mass%. The slurry was crushed for 3.5 hours with a wet ball mill using 1/8 inch stainless steel beads to obtain a slurry. The slurry was further crushed for 4.5 hours with a wet bead mill using zirconia with a diameter of 1 mm to obtain a calcined ferrite slurry having a volume-based 50% particle size (D50) of 0.7 μm.
Step 4 (granulation step)
To 100 parts of the calcined ferrite slurry, 1.0 part of ammonium polycarboxylate as a dispersant and 1.5 parts of polyvinyl alcohol as a binder were added, and the mixture was granulated into spherical particles and dried using a spray dryer (manufactured by Okawara Kakoki Co., Ltd.) The resulting granulated material was subjected to particle size adjustment and then heated at 700° C. for 2.0 hours using a rotary electric furnace to remove organic substances such as the dispersant and binder.
Step 5 (firing step)
The time required for the temperature to rise from room temperature to the firing temperature (1100° C.) was 2.0 hours under a nitrogen atmosphere (oxygen concentration 1.1% by volume), and the material was fired by holding the material at 1100° C. for 3.5 hours. The material was then cooled to 60° C. over 8 hours, returned from the nitrogen atmosphere to the air, and taken out at a temperature of 40° C. or less.
Step 6 (sorting step)
After the agglomerated particles were crushed, the particles were sieved through a sieve with 150 μm openings to remove coarse particles, air classification to remove fine powder, and magnetic separation to remove low magnetic force particles to obtain porous magnetic particles 1. The physical properties of porous magnetic particles 1 are shown in Table 2.
Step 7 (filling step)
100 parts of the porous magnetic particles are placed in a stirring vessel of a mixer (a universal mixer NDMV type manufactured by Dalton), and the temperature is kept at 60° C., and a filling resin consisting of 95.0% by mass of methyl silicone oligomer and 5.0% by mass of γ-aminopropyltrimethoxysilane is added to the vessel at normal pressure for 3.0 minutes.
Partially dripped.
After the dropwise addition was completed, stirring was continued while adjusting the time, and the temperature was raised to 70° C., thereby filling the porous magnetic particles with the resin composition.
After cooling, the resin-filled magnetic core particles obtained were transferred to a mixer (UD-AT type drum mixer manufactured by Sugiyama Heavy Industries Co., Ltd.) equipped with a spiral blade in a rotatable mixing vessel, and the temperature was raised to 220° C. at a rate of 2° C./min under a nitrogen atmosphere while stirring. Heating and stirring were then continued at 140° C. for 50 minutes.
After that, the mixture was cooled to room temperature, and the ferrite particles filled with the resin and hardened were taken out, and non-magnetic materials were removed using a magnetic separator. Furthermore, coarse particles were removed using a vibrating sieve to obtain magnetic core particles 1 filled with the resin.

<Production Examples of Porous Magnetic Particles 2 to 12 and Magnetic Core Particles 2 to 12>
Porous magnetic particles 2 to 12 and magnetic core particles 2 to 12 were obtained in the same manner as for porous magnetic particle 1, except that the production conditions were changed as shown in Table 1. The physical properties of porous magnetic particles 2 to 12 are shown in Table 2.

＊１ 多孔質磁性粒子１００部に対する部数である。

*1 Parts per 100 parts of porous magnetic particles.

<Production Example of Magnetic Material-Dispersed Resin Particles 1>
To magnetite powder having a number-average particle size of 0.30 μm, 4.0 mass % of a silane coupling agent (3-(2-aminoethylamino)propyltrimethoxysilane) was added, and the mixture was mixed and stirred at high speed at 100° C. or higher in a container.
10 parts phenol 6 parts formaldehyde solution (40% formaldehyde, 10% methanol, 50% water)
・84 parts of treated magnetite (D50: 2.1 μm) The above materials, 5 parts of 28% ammonia water, and 20 parts of water were put into a flask, and the temperature was raised to 85 ° C. in 30 minutes while stirring and mixing, and the mixture was polymerized for 3 hours to harden the resulting phenolic resin. After that, the hardened phenolic resin was cooled to 30 ° C., and water was added, and the supernatant liquid was removed, and the precipitate was washed with water and then air-dried. Then, the mixture was dried at a temperature of 60 ° C. under reduced pressure (5 mmHg or less) to obtain spherical magnetic material-dispersed resin particles 1 in which the magnetic material was dispersed.

<Production Example of Magnetic Material-Dispersed Resin Particles 2>
Magnetic material-dispersed resin particles 2 were obtained in the same manner as in the production example of magnetic material-dispersed resin particles 1, except that the treated magnetite had a D50 of 3.1 μm.

<Production Example of Magnetic Material-Dispersed Resin Particles 3>
Magnetic material-dispersed resin particles 3 were obtained in the same manner as in the production example of magnetic material-dispersed resin particles 1, except that the treated magnetite had a D50 of 3.8 μm.

<Production Example of Magnetic Material-Dispersed Resin Particles 4>
Magnetic material-dispersed resin particles 4 were obtained in the same manner as in the production example of magnetic material-dispersed resin particles 1, except that the treated magnetite had a D50 of 4.5 μm.

<Production Example of Magnetic Material-Dispersed Resin Particles 5>
Magnetic material-dispersed resin particles 5 were obtained in the same manner as in the production example of magnetic material-dispersed resin particles 1, except that the treated magnetite had a D50 of 4.9 μm.

<Production Examples of Resins A-1 and A-2>
The raw materials (55.0 parts in total) shown in Table 3 were added to a four-neck flask equipped with a reflux condenser, a thermometer, a nitrogen suction tube, and a grinding type stirrer, and 100.0 parts of toluene, 100.0 parts of methyl ethyl ketone, and 2.4 parts of azobisisovaleronitrile were further added, and the mixture was maintained at 80° C. for 10 hours under a nitrogen stream to obtain a coating resin A-1 solution (solid content 35% by mass).
Moreover, A-2 was obtained in the same manner using the raw materials shown in Table 3.

<Production Examples of Resins B-1 and B-2>
An autoclave was charged with 500 parts of xylene, and the inside of the autoclave was replaced with nitrogen, and the temperature was raised to 185° C. in a sealed state with stirring. A mixed solution of the raw materials (total of 100 parts) shown in Table 3, 5 parts of di-t-butyl peroxide, and 200 parts of xylene was continuously added dropwise for 3 hours while controlling the temperature inside the autoclave at 185° C., and polymerization was allowed to proceed. The temperature was further maintained for 1 hour to complete the polymerization, and the solvent was removed to obtain Resin B-1.
Similarly, B-2 was obtained using the raw materials shown in Table 3.

表中の略称は以下の通りである。
ＣＨＭＡ：メタクリル酸シクロヘキシル
ＭＭＡ：メタクリル酸メチル
マクロモノマーは、下記式（Ｍ）で表され、式（Ｍ）中のＺが下記構造（Ｚ）で示されるメタクリル酸メチル重合体であり、該マクロモノマーＭＭＡの重量平均分子量Ｍｗは５０００である。

The abbreviations in the table are as follows.
CHMA: cyclohexyl methacrylate MMA: methyl methacrylate The macromonomer is represented by the following formula (M), in which Z is represented by the following structure (Z), and is a methyl methacrylate polymer. The weight average molecular weight Mw of the macromonomer MMA is 5,000.

<Production Example of Magnetic Carrier 1>
Porous magnetic particles 1 100 parts Compound having an amino group (3-aminopropyltrimethoxysilane) 0.07 parts Porous magnetic particles 1: The compound having an amino group was diluted with isopropyl alcohol to 0.07 parts per 100 parts of the particles, and a thoroughly stirred solution was prepared.
100 parts of the porous magnetic particles were placed in a planetary mixer (Nauta Mixer VN type manufactured by Hosokawa Micron Corporation), and the mixture was stirred while the screw-shaped stirring blade revolved 3.5 revolutions per minute and rotated 100 revolutions per minute. Nitrogen was flowed at a flow rate of 0.2 ^m3 /min, and the pressure was adjusted to a reduced pressure (80 mmHg).
After heating to a temperature of 70°C, a compound having an amino group diluted 100 times with isopropyl alcohol was added. The coating operation was carried out for 20 minutes, and then the mixture was transferred to a mixer having a spiral blade (a drum mixer UD-AT type manufactured by Sugiyama Heavy Industries Co., Ltd.) in a rotatable mixing container, and heat-treated at a temperature of 150°C for 2 hours in a nitrogen atmosphere while stirring by rotating the mixing container 10 times per minute.

Resin A-1 1.50 parts Resin B-1 0.50 parts n-octyltriethoxysilane 0.20 parts Carbon black (Tokai Carbon #4400) 0.10 parts Next, porous magnetic particles treated with a compound having an amino group 1: The above components were diluted with toluene to a total of 3.0 parts per 100 parts of the particles, and the resin solution was thoroughly stirred to prepare a resin solution.
Thereafter, the porous magnetic particles 1 treated with a compound having an amino group were placed in a planetary mixer (Nauta Mixer VN type manufactured by Hosokawa Micron Corporation) maintained at a temperature of 60° C., and the above resin solution was added. The resin solution was added in a half amount, and the solvent was removed and the coating operation was carried out for 30 minutes. Next, another half amount of the resin solution was added, and the solvent was removed and the coating operation was carried out for 40 minutes.
The treated magnetic carrier was transferred to a mixer (UD-AT type drum mixer manufactured by Sugiyama Heavy Industries Co., Ltd.) having a spiral blade in a rotatable mixing container, and heat-treated at a temperature of 120°C for 2 hours in a nitrogen atmosphere while stirring at 10 revolutions per minute. Next, low magnetic products were separated by magnetic separation, passed through a sieve with an opening of 150 μm, and then classified by an air classifier to obtain magnetic carrier 1. The coating resin of the obtained magnetic carrier 1 was separated and measured by a GPC measuring device, and a peak was obtained in the molecular weight distribution as shown in Figure 3 or 4.

<Production Examples of Magnetic Carriers 2 to 15 and 17>
Magnetic Carriers 2 to 15 and 17 were obtained in the same manner as Magnetic Carrier 1, except that the types and amounts of materials added were changed as shown in Table 4. Table 5 shows the physical properties.

<Production Example of Magnetic Carrier 16>
Resin B-2 2.00 parts Carbon black 0.10 parts Quaternary ammonium salt charge control agent (P51 manufactured by Orient Co., Ltd.) 0.01 parts Porous magnetic particles 11: The above components were diluted with toluene to a total of 3.0 parts per 100 parts, and a thoroughly stirred resin solution was prepared.
Thereafter, the porous magnetic particles 1 treated with a compound having an amino group were placed in a planetary mixer (Nauta Mixer VN type manufactured by Hosokawa Micron Corporation) maintained at a temperature of 60° C., and the above resin solution was added. The resin solution was added in a half amount, and the solvent was removed and the coating operation was carried out for 30 minutes. Next, another half amount of the resin solution was added, and the solvent was removed and the coating operation was carried out for 40 minutes.
The treated magnetic carrier was transferred to a mixer (UD-AT type drum mixer manufactured by Sugiyama Heavy Industries Co., Ltd.) having a spiral blade in a rotatable mixing container, and heat-treated for 2 hours at a temperature of 120°C in a nitrogen atmosphere while stirring at 10 revolutions per minute. Next, low magnetic products were separated by magnetic separation, passed through a sieve with an opening of 150 μm, and then classified with an air classifier to obtain magnetic carrier 16.

＊１ 樹脂充填した多孔質磁性粒子１００部又は磁性体分散型樹脂粒子１００部に対する部数
＊２ 被覆樹脂中の質量％
＊３ 被覆樹脂１００部に対する部数

*1 Parts per 100 parts of resin-filled porous magnetic particles or 100 parts of magnetic material-dispersed resin particles *2 Mass % in the coating resin
*3 Parts per 100 parts of coating resin

<Toner Production Example>
[Production Example of Amorphous Polyester Resin (A)]
Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: 59.0 parts (0.15 moles; 80.0 mol% based on the total number of moles of polyhydric alcohol)
Polyoxyethylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: 13.6 parts (0.04 moles; 20.0 mol% based on the total number of moles of polyhydric alcohol)
Terephthalic acid: 20.8 parts (0.12 moles; 80.0 mol% based on the total number of moles of polycarboxylic acids)
Trimellitic anhydride: 6.6 parts (0.03 moles; 20.0 mol% based on the total number of moles of polycarboxylic acids)
The above materials were charged into a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen inlet tube, and a thermocouple. Then, 1.5 parts of tin 2-ethylhexanoate (esterification catalyst) was added as a catalyst to 100 parts of the total amount of monomers. Next, the atmosphere in the flask was replaced with nitrogen gas, and the temperature was gradually raised while stirring, and the reaction was carried out for 2.5 hours while stirring at a temperature of 200°C.
The pressure in the reaction vessel was then reduced to 8.3 kPa and maintained for 1 hour, after which the vessel was cooled to 180° C. and reacted as is. After it was confirmed that the softening point measured according to ASTM D36-86 reached 110° C., the temperature was reduced to stop the reaction. The resulting amorphous polyester resin (A) had a softening point (Tm) of 110° C. and an acid value of 10 mgKOH/g.

[Production Example of Amorphous Polyester Resin (B)]
Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: 73.4 parts (0.19 moles; 100.0 mol% based on the total number of moles of polyhydric alcohol)
Terephthalic acid: 11.6 parts (0.07 moles; 80.0 mol% based on the total number of moles of polycarboxylic acids)
Adipic acid: 6.8 parts (0.05 moles; 14.0 mol% based on the total number of moles of polycarboxylic acids)
The above materials were weighed and put into a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen inlet tube, and a thermocouple. The atmosphere in the flask was then replaced with nitrogen gas, and the temperature was gradually raised with stirring, and the reaction was carried out for 2 hours at a temperature of 200°C while stirring.
Furthermore, the pressure inside the reaction vessel was reduced to 8.3 kPa and maintained for 1 hour, after which the reaction vessel was cooled to 180° C. and returned to atmospheric pressure (first reaction step).
Trimellitic anhydride: 8.2 parts (0.04 moles; 6.0 mol% based on the total number of moles of polycarboxylic acids)
tert-Butylcatechol (polymerization inhibitor): 0.1 part. The above materials were then added, the pressure in the reaction vessel was lowered to 8.3 kPa, and the reaction was continued for 12 hours while maintaining the temperature at 160° C. The reaction was stopped by lowering the temperature (second reaction step), and an amorphous polyester resin (B) was obtained. The obtained amorphous polyester resin (B) had a softening point of 160° C. and an acid value of 25 mgKOH/g.

Amorphous polyester resin (A) 70 parts Amorphous polyester resin (B) 30 parts C.I. Pigment Blue 15:3 5.5 parts 3,5-di-t-butyl salicylic acid aluminum compound 0.2 parts Normal paraffin wax (melting point: 90 ° C.) 6 parts The above-mentioned materials were mixed well with a Henschel mixer (FM-75J type, manufactured by Nippon Coke & Co., Ltd.), and then kneaded at a feed rate of 10 kg / hr with a two-screw kneader (trade name: PCM-30 type, manufactured by Ikegai Steel Co., Ltd.) set at a temperature of 130 ° C. (The kneaded material temperature at the time of discharge was 150 ° C.). The kneaded material obtained was cooled, crushed with a hammer mill, and then finely pulverized with a mechanical crusher (trade name: T-250, manufactured by Turbo Kogyo Co., Ltd.) at a feed rate of 15 kg / hr. Particles were obtained that had a weight average particle size of 5.5 μm, contained 55.6% by number of particles with a particle size of 4.0 μm or less, and contained 0.8% by volume of particles with a particle size of 10.0 μm or more.
The obtained particles were classified to remove fine powder and coarse powder using a rotary classifier (product name: TTSP100, manufactured by Hosokawa Micron Corp.) to obtain toner particles 1 having a weight average particle size of 6.0 μm, a content rate of particles having a particle size of 4.0 μm or less of 27.8% by number, and a content rate of particles having a particle size of 10.0 μm or more of 2.2% by volume.

The obtained toner particles 1 were subjected to a heat treatment by the surface treatment device shown in Fig. 1 to obtain heat-treated toner particles. The operating conditions were as follows: feed rate = 5 kg/hr, hot air temperature = 160°C, hot air flow rate = 6 ^m3 /min, cold air temperature = -5°C, cold air flow rate = 4 ^m3 /min, blower air flow rate = 20 ^m3 /min, injection air flow rate = 1 ^m3 /min.

The obtained heat-treated toner particles 1 and the following materials were then charged into a Henschel mixer (product name: FM-75J type, manufactured by Nippon Coke & Engineering Co., Ltd.). The peripheral speed of the rotating blades was set to 35.0 (m/sec), and the mixing time was set to 3 minutes, whereby the following materials were adhered to the surfaces of the heat-treated toner particles 1, thereby obtaining a cyan toner 1.
Heat-treated toner particles 1: 100 parts Silica particles: 3.5 parts (silica particles produced by a fumed method, surface-treated with 1.5% by mass of hexamethyldisilazane, and then classified to obtain a desired particle size distribution)
Titanium oxide particles: 0.5 parts (metatitanic acid having anatase crystallinity, surface-treated with an octylsilane compound)
Strontium titanate particles: 0.5 parts (surface treated with an octylsilane compound)

Using each of the above magnetic carriers 1 to 17 and cyan toner 1, the toner concentration was 8%.
Each material was shaken in a shaker (YS-8D type: manufactured by Yayoi Co., Ltd.) so as to obtain two-component developers 1 to 17. The vibration conditions of the shaker were 200 rpm and 2 minutes.

<Examples 1 to 15 and Comparative Examples 1 to 2>
A modified Canon imagePRESS C800 full-color copier was used as the image forming apparatus to be evaluated. This image forming apparatus has a photoconductor that forms an electrostatic latent image as an image carrier, and has a developing process in which the electrostatic latent image on the photoconductor is developed into a toner image by a two-component developer. It also has a transfer process in which the developed toner image is transferred to an intermediate transfer body, and then the toner image on the intermediate transfer body is transferred to paper, and a fixing process in which the toner image on the paper is fixed by heat. Two-component developers 1 to 17 were charged into the developer of the cyan station of this image forming apparatus, and evaluation was performed. The evaluation results are shown in Table 6.

表中、ＳＤは、標準偏差を示す。

In the table, SD indicates standard deviation.

<Evaluation 1 of durability and stability>
The image forming apparatus was a Canon imagePress C800 full-color copier, and the above-mentioned two-component developer was placed in a cyan developer of the image forming apparatus, and the evaluation described below was performed. The modification was to remove the mechanism for discharging the excess magnetic carrier from the developer.
The amount of toner laid on the paper in the FFh image (solid image) was adjusted to 0.45 mg/ ^cm2 . FFh is a value obtained by expressing 256 gradations in hexadecimal, where 00h is the first gradation (white background) of the 256 gradations, and FF is the 256th gradation (solid area) of the 256 gradations.
(conditions)
Paper: Laser beam printer paper CF-081 (81.4 g/m ² ) (Canon Marketing Japan Inc.)
Image forming speed: A4 size, full color 85 sheets/min
Development conditions: The development contrast was made adjustable to any value, and the automatic correction by the main body was not activated. The peak-to-peak voltage (Vpp) of the alternating electric field was modified to a frequency of 2.0 kHz, and Vpp was modified to be variable in 0.1 kV increments from 0.7 kV to 1.8 kV. Each color was modified to output a monochrome image.

In the durability test, a durability test of outputting 10,000 images was carried out.
The test conditions were a low temperature and low humidity environment (temperature 5°C, relative humidity 15%) with a 1% image ratio, and a high temperature and high humidity environment (temperature 30°C, relative humidity 80%) with a 40% image ratio. During the continuous passing of 10,000 sheets, the sheets were passed under the same development and transfer conditions (without calibration) as the first sheet.
The items and evaluation criteria for image output evaluation at the initial stage (first sheet) and after continuous feeding of 10,000 sheets are shown below.
Using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite), the image density of the FFh image area at the initial (first sheet) and 10,000th sheet was measured, and the difference Δ between the two image densities was ranked according to the following criteria. When the evaluation was A to C, it was determined that the effects of the present invention were obtained. The evaluation results are shown in Table 6.
A: Less than 0.20 B: 0.20 or more and less than 0.75 C: 0.75 or more and less than 1.00 D: 1.00 or more and less than 1.25 E: 1.25 or more

<Evaluation of image uniformity>
After the above-mentioned 10,000 sheets of durable output, a solid image was output, and a 2 cm square image was captured with a digital microscope. The captured image was converted to 8-bit grayscale using Image-J (available from https://imagej.nih.gov/ij/), and then a density histogram was measured and its standard deviation was calculated. The standard deviation was ranked according to the following evaluation criteria. When the evaluation was A to C, it was determined that the effect of the present invention was obtained.
A: Standard deviation less than 2.0 B: Standard deviation 2.0 or more and less than 4.0 C: Standard deviation 4.0 or more and less than 6.0 D: Standard deviation 6.0 or more and less than 8.0 E: Standard deviation 8.0 or more

<Evaluation of Fog>
After the durability test of 10,000 sheets, an all-white image was output, and the fog density on the paper after durability test was measured. The reflectance (%) of the all-white image output after durability test was measured at three points using "REFLECTOMETER MODEL TC-6DS" (manufactured by Tokyo Denshoku Co., Ltd.), and the average value was calculated. The average reflectance obtained was subtracted from the reflectance (%) of unused paper (standard paper) measured in the same manner, and the result was used for evaluation. The evaluation results of fog were ranked as follows. It was determined that the effects of the present invention were obtained when the evaluation was A to C.
A: Fog density is less than 0.5% B: Fog density is 0.5% or more and less than 0.8% C: Fog density is 0.8% or more and less than 1.1% D: Fog density is 1.1% or more and less than 1.5% E: Fog density is 1.5% or more

1. Means for supplying a fixed amount of raw material, 2. Means for adjusting the flow rate of compressed gas, 3. Introduction pipe, 4. Projection-shaped member, 5. Supply pipe, 6. Processing chamber, 7. Means for supplying hot air, 8. Means for supplying cold air, 9. Regulating means, 10. Recovery means, 11. Hot air supply means outlet, 12. Distribution member, 13. Rotation member, 14. Powder particle supply port

Claims (8)

A magnetic carrier,
The magnetic carrier has a compound having an amino group on the surface of a magnetic core particle, and further has a resin coating layer thereon,
the compound having an amino group is exposed on at least a part of the surface of the magnetic carrier,
a nitrogen atom concentration detected by a surface analysis of the magnetic carrier by X-ray photoelectron spectroscopy is 0.40 atomic % or more and 1.00 atomic % or less;
The magnetic core particle comprises a porous magnetic particle and a filler present in the pores of the porous magnetic particle;
The average pore size of the porous magnetic particles is 0.40 μm or more and 0.60 μm or less,
The porous magnetic particles have an integrated pore volume of 40 mm ³ /g or more and 60 mm ³ /g or less ;
The magnetic carrier is characterized in that the resin coating layer contains 5.0 to 20.0 parts by mass of a silane compound represented by the following formula (3) relative to 100 parts by mass of the coating resin .

(In the formula, R ₁ represents a chain alkyl group having 6 to 12 carbon atoms, and R ₂ each independently represents a methyl group or an ethyl group.) A magnetic carrier,
The magnetic carrier has a compound having an amino group on the surface of a magnetic core particle, and further has a resin coating layer thereon,
the compound having an amino group is exposed on at least a part of the surface of the magnetic carrier,
The nitrogen atom concentration detected by surface analysis of the magnetic carrier by X-ray photoelectron spectroscopy is 0.
40 atomic% or more and 1.00 atomic% or less,
The magnetic core particle comprises a porous magnetic particle and a filler present in the pores of the porous magnetic particle;
the content of the filler is 1.0 part by mass or more and 8.0 parts by mass or less relative to 100 parts by mass of the porous magnetic particles,
The magnetic carrier is characterized in that the resin coating layer contains 5.0 to 20.0 parts by mass of a silane compound represented by the following formula (3) per 100 parts by mass of the coating resin .

(In the formula, R ₁ represents a chain alkyl group having 6 to 12 carbon atoms, and R ₂ each independently represents a methyl group or an ethyl group.) In a backscattered electron image of the magnetic carrier taken by a scanning electron microscope at an acceleration voltage of 2.0 kV,
The backscattered electron image is acquired as an 8-bit, 256-level grayscale image, and the portion with a luminance range of 140 to 255 is designated as Lu.
3. The magnetic carrier according to claim 1, wherein the diameter of Lu is from 0.10 μm to 1.00 μm. The magnetic carrier according to claim 3, wherein the average closest distance between the Lu's is 1.0 μm or more and 3.0 μm or less. 5. The magnetic carrier according to claim 3, wherein the ratio Ar of the total area of Lu to the total projected area of the magnetic carrier, calculated from the following formula (1), is 5.0% or more and 15.0% or less:
Ar = (total area of Lu / total projected area of magnetic carrier) × 100 (1) The magnetic carrier according to any one of claims 1 to 5, wherein the content of the compound having an amino group is 0.010 parts by mass or more and 0.100 parts by mass or less per 100 parts by mass of the magnetic core particles. A two-component developer including a magnetic carrier and a toner,
The magnetic carrier is the magnetic carrier according to any one of claims 1 to 6,
The toner is negatively charged,
The toner has toner particles and inorganic fine particles,
The two-component developer has inorganic fine particles that are negatively chargeable. 8. The two-component developer according to claim 7, wherein the adhesion rate of the inorganic fine particles to the toner particles is 80.0% or more and 95.0% or less.

Images