JP6987657B2 - Magnetic carrier, two-component developer, replenisher developer, image forming method, and method for manufacturing magnetic carrier - Google Patents

Description

The present invention is a magnetic carrier used as a two-component developer for developing (visualizing) an electrostatic latent image (electrostatic charge image) by an electrophotographic method, and a two-component developer having the magnetic carrier. Regarding.

In recent years, the electrophotographic method has been widely used in copiers, printers, and the like, and is required to be able to handle various objects such as fine lines, lowercase letters, photographs, and color originals. Furthermore, there are also demands for higher image quality, higher quality, higher speed, and continuity, and it is expected that these demands will continue to increase in the future.
Since the carrier particles satisfying these requirements are required to be lightweight, the magnetic carrier core material used for the magnetic carrier particles is generally composed of a resin and a magnetic material in recent years. Magnetic ferrite particles, which are often used as magnetic carrier particles in the past, are heavy particles having a specific gravity of 4.7 or more, but the specific gravity of the magnetic material dispersion type resin carrier core material particles composed of a resin and a magnetic material is about 2. A wide range of designs from .0 to 4.7 are possible.

On the other hand, as a technique for reducing concentration fluctuations even in long-term use and color fluctuations in the case of full color, there is an example of coating the magnetic carrier core material with a resin, and the magnetic material dispersion type resin carrier core material is coated with a resin. Examples (see Patent Documents 1 to 3) have been proposed.
However, the magnetic material-dispersed resin carrier core material coated with such a resin does not have sufficient durability of the resin coating layer, and when the resin coating layer becomes thin due to long-term use of the magnetic carrier. There was a problem that a leak phenomenon and white spots could occur.
Patent Documents 4 to 8 propose examples of suppressing the leakage phenomenon to the photoconductor by controlling the surface resistance of the magnetic carrier, but further improvement is desired.

Japanese Unexamined Patent Publication No. 2013-210584 Japanese Unexamined Patent Publication No. 2012-123212 Japanese Unexamined Patent Publication No. 2012-123213 Japanese Unexamined Patent Publication No. 6-07534 Japanese Unexamined Patent Publication No. 2010-055086 Japanese Patent Application Laid-Open No. 2002-072545 Japanese Unexamined Patent Publication No. 2008-090012 Japanese Unexamined Patent Publication No. 2005-316506

Further, in the magnetic material dispersion type resin carrier core material coated with resin, the balance between the transportability and the stirring property of the developing agent in the developing device is affected, and the stirring of the replenished toner and the developing agent cannot catch up with the developing. There is also a problem that the concentration stability and the in-plane uniformity are lowered when the agent comes to the developing part. As a career approach to this issue, no countermeasures have been found, and it was necessary to find an improvement method.
An object of the present invention is to provide a magnetic carrier that improves the mixability and transportability of a developer and does not impair the whitening resistance and leak resistance of an image even when the resin coating layer is thinned. ..
A further object of the present invention is to provide a two-component developer having the above magnetic carrier.

The present invention is a magnetic carrier having a magnetic material dispersion type resin carrier core material and magnetic carrier particles having a resin coating layer formed on the magnetic material dispersion type resin carrier core material.
The magnetic material dispersion type resin carrier core material is
The number of primary particles contains magnetic particles A having an average particle diameter of ra (μm) and magnetic particles B having an average number of primary particles of rb (μm).
The ra and the rb is, satisfy the relationship of ra> rb,
The magnetic particles A contain an oxide of at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element, and iron oxide.
In the measurement of the magnetic carrier particles by the fluorescent X-ray diffractometry, when the total content of the non-ferrous metal element is M1 (mass%) and the content of the iron element is F1 (mass%), the ratio of M1 to F1. The value (M1 / F1) of is 0.010 or more and 0.100 or less.
In the measurement of the magnetic carrier particles by X-ray photoelectron spectroscopy, when the total content of the non-iron metal element is M2 (mass%) and the content of the iron element is F2 (mass%), it is relative to F2 of M2. The magnetic carrier has a ratio value (M2 / F2) of 1.0 or more and 10.0 or less.
Further, the present invention is a two-component developer and a supplementary developer having the magnetic carrier and toner. Further, the present invention relates to an image forming method using the magnetic carrier.
Further, the present invention is a method for manufacturing a magnetic carrier having magnetic carrier particles.
Magnetic particles A, magnetic particles B, basic catalysts, phenols, aldehydes and an aqueous medium are mixed and heated with stirring to react the phenols with the aldehydes, and the magnetism is contained in the phenol resin. A step of manufacturing a magnetic material-dispersed resin carrier core material in which the particles A and the magnetic particles B are dispersed, and
It has a step of forming a resin coating layer on the surface of the magnetic material dispersion type resin carrier core material and obtaining magnetic carrier particles.
When the number average particle diameter of the primary particles of the magnetic particles A is ra (μm) and the number average particle diameter of the primary particles of the magnetic particles B is rb (μm), the ra and the rb are ra> rb. Meet the relationship,
The magnetic particles A contain an oxide of at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element, and iron oxide.
In the measurement of the magnetic carrier particles by the fluorescent X-ray diffractometry, when the total content of the non-ferrous metal element is M1 (mass%) and the content of the iron element is F1 (mass%), the ratio of M1 to F1. The value (M1 / F1) of is 0.010 or more and 0.100 or less.
In the measurement of the magnetic carrier particles by X-ray photoelectron spectroscopy, when the total content of the non-iron metal element is M2 (mass%) and the content of the iron element is F2 (mass%), it is relative to F2 of M2. It is a method for manufacturing a magnetic carrier, characterized in that the ratio value (M2 / F2) is 1.0 or more and 10.0 or less.

According to the present invention, it is possible to provide a magnetic carrier that improves the mixability and transportability of the developer and does not impair the whitening resistance and leak resistance of the image even when the resin coating layer is thinned. .. Further, it is possible to provide a two-component developer having the magnetic carrier.

Schematic diagram of an image forming apparatus that can be used in the present invention. Schematic diagram of an image forming apparatus that can be used in the present invention. Schematic diagram of the coating resin content specification method in the GPC molecular weight distribution curve Schematic diagram of the coating resin content specification method in the GPC molecular weight distribution curve Schematic diagram of resistivity measuring device for magnetic carriers

In the present invention, the description of "○○ or more and XX or less" and "○○ to XX" indicating a numerical range means a numerical range including a lower limit and an upper limit which are end points, unless otherwise specified.
The magnetic carrier of the present invention is a magnetic carrier having a magnetic material dispersion type resin carrier core material and magnetic carrier particles having a resin coating layer formed on the magnetic material dispersion type resin carrier core material.
The magnetic material dispersion type resin carrier core material is
The number of primary particles contains magnetic particles A having an average particle diameter of ra (μm) and magnetic particles B having an average number of primary particles of rb (μm).
The ra and rb satisfy the relationship of ra ≧ rb, and
The magnetic particles A contain an oxide of at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element, and iron oxide.
In the measurement of the magnetic carrier particles by the fluorescent X-ray diffractometry, when the total content of the non-ferrous metal element is M1 (mass%) and the content of the iron element is F1 (mass%), the ratio of M1 to F1. The value (M1 / F1) of is 0.010 or more and 0.100 or less.
In the measurement of the magnetic carrier particles by X-ray photoelectron spectroscopy, when the total content of the non-iron metal element is M2 (mass%) and the content of the iron element is F2 (mass%), it is relative to F2 of M2. The magnetic carrier has a ratio value (M2 / F2) of 1.0 or more and 10.0 or less.

There are many methods for preventing the leak phenomenon and whiteout caused by the thinning of the resin coating layer formed on the magnetic material dispersion type resin carrier core material.
The first method is a method of increasing the resistance of the magnetic carrier resin coating layer, and examples thereof include a method of thickening the resin coating layer and a method of adding a high resistance component to the resin coating layer. However, it is difficult to adjust the resistance with these methods, and after long-term use, the resistance changes due to the thinning of the resin coating layer, and the image density is not stable.
The second method is to increase the resistance of the magnetic material dispersion type resin carrier core material. Among them, the method of adding a high resistance component to the magnetic material dispersion type resin carrier core material had a low effect of improving the leak resistance, and the occurrence of carrier scattering due to a decrease in the amount of magnetization was observed. In addition, the resistance becomes too high in the method of ferriteizing the magnetic material, and it is very difficult to control it.

Therefore, the present inventors have found a method for unevenly distributing a high resistance component on the surface layer portion of the magnetic material dispersion type resin carrier core material, while preventing the resistance of the magnetic material dispersion type resin carrier itself from increasing. Has been resolved.
In the present invention, in the measurement of magnetic carrier particles by the fluorescent X-ray diffractometry, when the total content of non-ferrous metal elements is M1 (mass%) and the content of iron elements is F1 (mass%), F1 of M1 The value of the ratio to (M1 / F1) is 0.010 or more and 0.100 or less, preferably 0.020 or more and 0.090 or less. This shows the ratio other than the iron oxide component present inside the magnetic material dispersion type resin carrier core material described later. When M1 / F1 is less than 0.010, the density of the image output after high density output becomes unstable. On the other hand, if it exceeds 0.100, the density of the image output after low density output becomes unstable. M1 / F1 can be controlled by the ratio of the magnetic particles A and the magnetic particles B. For example, M1 / F1 can be increased by increasing the ratio of the magnetic particles A.

In the present invention, in the measurement of magnetic carrier particles by X-ray photoelectron spectroscopy, when the total content of non-ferrous metal elements is M2 (mass%) and the content of iron elements is F2 (mass%), F2 of M2 The value of the ratio to (M2 / F2) is 1.0 or more and 10.0 or less. It is preferably 1.5 or more and 8.5 or less, and more preferably 1.8 or more and 6.0 or less. This shows the ratio other than the iron oxide component present on the surface layer of the magnetic material dispersion type resin carrier core material described later. When M2 / F2 is less than 1.0, the density of the image output after high density output becomes unstable. On the other hand, if it exceeds 10.0, the density of the image output after low density output becomes unstable. M2 / F2 can be controlled by the coating amount of the non-ferrous metal element of the magnetic particles A described later. For example, M2 / F2 can be increased by increasing the coating amount of the non-ferrous metal element component of the magnetic particles A.

The fact that (M1 / F1) and (M2 / F2) are in the above range indicates that the non-ferrous metal element is unevenly distributed on the surface layer of the magnetic material-dispersed resin carrier. As a result, both leak resistance and reduction of white spots can be achieved.
In the measurement of M1 and M2, the nonferrous metal element is preferably at least one selected from the group consisting of manganese element, aluminum element, magnesium element, titanium element, and nickel element. By selecting the above as the non-ferrous metal element component, it becomes easier to control the charge retention and charge relaxation. As a result, it is considered that the electrostatic adhesion between the toner and the magnetic carrier and the fluidity of the developer are stabilized, the stirring property and the transportability of the developer are improved, and the concentration stability and the in-plane uniformity are improved.

Further, the sum (M2 + F2) of the M2 (mass%) and the F2 (mass%) is preferably 1.0% or more and 5.0% or less, and 1.3% or more and 4.8% or less. It is more preferable to have. Within the above range, concentration stability and in-plane uniformity are likely to be improved. M2 + F2 can be controlled by the amount of the coating resin layer. For example, by increasing the amount of the coating resin, the coating layer formed on the magnetic carrier becomes thicker, and M2 + F2 becomes smaller.

The magnetic material dispersion type resin carrier core material contains magnetic particles A having an average number of primary particles of ra (μm) and magnetic particles B having an average number of primary particles of rb (μm). ra and rb satisfy the relationship of ra ≧ rb. The magnetic particles A contain an oxide of at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element, and iron oxide.
In the magnetic material dispersion type resin carrier core material, the magnetic particles A are preferably unevenly distributed on the surface layer portion of the carrier core material, and further from the group consisting of manganese element, aluminum element, magnesium element, titanium element, and nickel element. It is preferable that the oxide of at least one selected non-ferrous metal element is unevenly distributed on the surface layer of the magnetic particles A.
As a result, the stability of the concentration and the in-plane uniformity are stabilized, and leakage and white spots can be reduced.

The specific resistance of the magnetic carrier at an electric field strength of 2000 (V / cm) is preferably 1 × 10 ⁶ (Ω · cm) or more and 1 × 10 ¹² (Ω · cm) or less. More preferably, it is 1 × 10 ⁷ (Ω · cm) or more and 1 × 10 ¹¹ (Ω · cm) or less.
Within this range, it is possible to easily achieve both leak resistance and suppression of white spots.
The true specific gravity of the magnetic carrier is preferably 2.5 or more and 4.4 or less, and more preferably 3.0 or more and 4.1 or less. Within the above range, the balance between agitation and transportability is excellent, and the stability of concentration and the in-plane uniformity are further stabilized.

The resin coating layer preferably contains a polymer (coating resin A) of a monomer containing a (meth) acrylic acid ester having at least an alicyclic hydrocarbon group. Such a resin has a function of smoothing the coating film surface of the resin coated on the magnetic material dispersion type resin carrier core material, suppressing the adhesion of toner-derived components, and suppressing the decrease in chargeability. In addition, the stirring speed of the developer is stabilized, and the stability of the concentration and the in-plane uniformity are further stabilized.
A monomer containing a (meth) acrylic acid ester having an alicyclic hydrocarbon group includes, for example, cyclobutyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, cycloheptyl acrylate, dicyclopentenyl acrylate, dicyclopenta acrylate. Nyl, cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, dicyclopentenyl methacrylate, dicyclopentanyl methacrylate and the like can be mentioned. One kind or two or more kinds of these monomers may be selected and used.

Further, the resin coating layer (coating resin A) is other than the (meth) acrylic acid ester having the alicyclic hydrocarbon group and the (meth) acrylic acid ester having the alicyclic hydrocarbon group. It is preferable to contain a copolymer of other (meth) acrylic monomers.
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 hereinafter). , Butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, acrylic acid or methacrylic acid and the like.

The weight average molecular weight (Mw) of the coating resin A used for the resin coating layer is preferably 2000 or more and 10000 or less, and more preferably 3000 or more and 8000 or less.
The amount of the (meth) acrylic acid ester monomer having an alicyclic hydrocarbon group to be used is preferably 50.0% by mass or more and 95.0% by mass or less based on all the monomers of the coating resin A, and more. It is preferably 50.0% by mass or more and 90.0% by mass or less.
The content of the resin coating layer is preferably 0.5 parts by mass or more and 5.0 parts by mass or less, and more preferably 1.0 part by mass or more and 4 parts by mass with respect to 100 parts by mass of the magnetic material dispersion type resin carrier core material. It is 0.5 parts by mass or less. Within the above range, it is possible to reduce the difference in environment and the difference in image density before and after leaving.

Further, the resin coating layer (coating resin A) is more preferably a copolymer resin of a (meth) acrylic acid ester monomer having an alicyclic hydrocarbon group and a macromonomer. By using the macromonomer, the transport stability of the developer is more effective, and the stability of the image density is also improved. As the monomer that can be used as the macromonomer, styrene, acrylonitrile, methacrylonitrile, or the like can be used in addition to the above-mentioned monomers as other (meth) acrylic monomers.
The macromonomer includes methyl acrylate, methyl methacrylate, butyl acrylate (n-butyl, sec-butyl, iso-butyl or tert-butyl), butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and the like. It is preferably a polymer of at least one monomer selected from the group consisting of styrene, acrylonitrile, and methacrylic nitrile.

The weight average molecular weight (Mw) of the macromonomer is preferably 2000 or more and 10000 or less, and more preferably 3000 or more and 8000 or less.
The amount of the macromonomer used is preferably 5.0% by mass or more and 50.0% by mass or less, preferably 5.0% by mass or more and 40.0% by mass or less, based on all the monomers of the coating resin A. Is more preferable.

Next, a case where two or more kinds of resin compositions are used for the resin coating layer will be described. In the present invention, for coating, which is a polymer (or copolymer) of a (meth) acrylic acid ester monomer having an alicyclic hydrocarbon group and, if necessary, other (meth) acrylic monomers and macromonomers. It is also possible to use a blend of the resin A and the coating resin B having a specific acid value. The coating resin B is preferably a polymer of a monomer containing at least the other (meth) acrylic monomer. As a result, not only the transport stability is improved, but also the coating film strength of the coating film is improved, and the concentration stability is further improved.
When the coating resin A and the coating resin B are used for the resin coating layer, the mass ratio (A: B) thereof is preferably 9: 1 to 1: 9, and more preferably 8: 2 to 2. : 8.

The coating resin A is a copolymer of a (meth) acrylic acid ester having an alicyclic hydrocarbon group and another (meth) acrylic monomer, or a (meth) acrylic acid having an alicyclic hydrocarbon group. It is preferable to use a copolymer of an ester, another (meth) acrylic monomer and a macromonomer. The acid value of the coating resin A is preferably 0.0 mgKOH / g or more and 3.0 mgKOH / g or less, and more preferably 0.0 mgKOH / g or more and 2.5 mgKOH / g or less.

The acid value of the coating resin B is preferably 3.5 mgKOH / g or more and 50.0 mgKOH / g or less, more preferably 4.0 mgKOH / g or more and 50.0 mgKOH / g or less, and 4.5 mgKOH / g or more and 40. It is more preferably 0 mgKOH / g or less. When two or more kinds of coating resins are used for the resin coating layer, the effect of reducing the environmental difference and the image density difference before and after leaving is improved when the acid value is within the above range. The acid value of the resin can be controlled by the monomer used.

The core material of the magnetic carrier will be described.
The magnetic material dispersion type resin carrier core material used in the present invention has a magnetic material and a binder resin, and the magnetic material has magnetic particles A and B. When the magnetic particles having an average number of primary particles of ra (μm) are magnetic particles A and the magnetic particles having an average number of primary particles of rb (μm) are magnetic particles B, ra (μm) and rb ( μm) has a relationship of ra ≧ rb, but preferably ra> rb.
When ra and rb have the above relationship, the concentration stability and the in-plane uniformity can be easily improved.
Examples of the magnetic particles include magnetite particles and maghemite particles.
A preferred embodiment of the magnetic particles A and the magnetic particles B is to include magnetite particles. Further, in the magnetic particles A, the surface of the magnetic particles is coated with an oxide of at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element. Is more preferable. The magnetic particles B may also be coated with at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element, but the non-ferrous metal element is more preferable. Magnetite particles uncoated with elements.

Further, the number average particle diameter ra (μm) of the primary particles of the magnetic particles A is preferably 0.30 μm or more and 3.00 μm or less, and more preferably 0.60 μm or more and 2.80 μm or less. The number average particle diameter rb (μm) of the primary particles of the magnetic particles B is preferably 0.10 μm or more and 2.50 μm or less, and more preferably 0.15 μm or more and 1.50 μm or less.
The content of at least one nonferrous metal element component selected from the group consisting of manganese element, aluminum element, magnesium element, titanium element, and nickel element in the magnetic particles A is 20% by mass or more and 40% by mass or less. It is preferable, and more preferably, it is 21% by mass or more and 35% by mass or less. Further, the content of the magnetic particles A in the magnetic particles used for the magnetic material dispersion type resin carrier core material is preferably 2.0% by mass or more and 20.0% by mass or less.

Examples of the method for adjusting the magnetic particles A include the following methods. Magnetite nuclei are produced, then the slurry containing the nuclei is maintained in the temperature range of 70-95 ° C. and the pH of the slurry is controlled in the range of 8.0-9.0.
Here, when the non-ferrous metal element is an aluminum element, an aluminum salt is added at a ratio of 0.015% by weight / min or less with respect to the nuclear particles. After that, the magnetic particles A can be obtained by aging for 30 minutes or more, adjusting the pH, washing with water and drying according to a conventional method. When the non-ferrous metal element is magnesium element, manganese element, nickel element or titanium element, the pH of the slurry containing the nuclear particles is 9.5 to 10.5 for magnesium element and 8.0 for manganese element. ~ 9.0, 7.5-8.5 for nickel element, 8.0-9.0 for titanium element, each metal salt is 0.015 mass with respect to nuclear particles. Magnetic particles A can be obtained by adding at% / min or less, aging for 30 minutes or more, adjusting the pH, washing with water and drying according to a conventional method.
Further, when the magnetic particles B are also coated, they can be adjusted by the same method as the above magnetic particles A, but when they are not coated, the magnetite nuclear particles can be used as they are.

In addition to the above magnetic particles (magnetic inorganic compound particles), non-magnetic iron oxide particles such as hematite particles, non-magnetic ferric hydroxide particles such as gateite particles, titanium oxide particles, silica particles, talc particles, and alumina particles, Non-magnetic inorganic compound particles such as barium sulfate particles, barium carbonate particles, cadmium yellow particles, calcium carbonate particles, and zinc flower particles can be used in combination.
When the magnetic inorganic compound particles and the non-magnetic inorganic compound particles are used in combination, the mixing ratio thereof is preferably 30% by mass or more of the magnetic inorganic compound particles based on the total mass of both particles.

It is preferable that all or part of the magnetic inorganic compound particles and the non-magnetic inorganic compound particles are treated with a lipophilic treatment agent.
As the oil-forming treatment agent, for example, at least one functional group selected from the group consisting of an epoxy group, an amino group, a mercapto group, an organic acid group, an ester group, a ketone group, an alkyl halide group and an aldehyde group can be used. Examples thereof include organic compounds having the same, and mixtures of these organic compounds.
As the organic compound having a functional group, a coupling agent is preferable. Among the coupling agents, a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent are more preferable. Among them, silane-based coupling agents are more preferable.

As the binder resin used for the magnetic material dispersion type resin carrier core material, a thermosetting resin is preferable.
Examples of the thermosetting resin include phenol resin, epoxy resin, polyester resin (for example, unsaturated polyester resin) and the like. Among these, phenolic resin is preferable from the viewpoint of low cost and ease of manufacture. Examples of the phenol resin include a phenol-formaldehyde resin.
The ratio of the binder resin constituting the magnetic material dispersion type resin carrier core material is preferably 1% by mass or more and 20% by mass or less based on the total mass of the magnetic material dispersion type resin carrier core material. Further, the ratio of the magnetic particles (magnetic inorganic compound particles) and, if necessary, the non-magnetic inorganic compound particles shall be 80% by mass or more and 99% by mass or less based on the total mass of the magnetic material dispersion type resin carrier core material. Is preferable.

A method for manufacturing a magnetic material dispersion type resin carrier core material will be described.
The magnetic material dispersion type resin carrier core material is, for example, first containing phenols and aldehydes in an aqueous medium in the presence of magnetic particles A and B (and, if necessary, non-magnetic inorganic compound particles) and a basic catalyst. And stir. Then, the phenols and the aldehydes are reacted and cured to produce a magnetic material dispersion type resin carrier core material containing the magnetic particles A and B and the phenol resin.
Further, it is also possible to produce a magnetic material dispersion type resin carrier core material by a so-called kneading pulverization method or the like in which the resin containing the magnetic particles A and B is pulverized. The former method is preferable from the viewpoint of easy control of the particle size of the magnetic carrier and the sharp particle size distribution of the magnetic carrier.

The method of covering the surface of the magnetic material dispersion type resin carrier core material with a coating resin to provide a resin coating layer is not particularly limited, but is such as a dipping method, a spray method, a brush coating method, a dry method, and a fluidized bed. Various application methods can be mentioned.
Methods for suppressing granulation during the coating process include adjusting the resin concentration in the coating resin composition solution, the temperature inside the coating device, the temperature and decompression degree when removing the solvent, and the number of times the resin coating process is performed. Can be mentioned.

Further, the coating resin composition may contain particles having conductivity or particles or materials having charge controllability. Examples of the conductive particles include carbon black, magnetite, graphite, zinc oxide, and tin oxide.
The amount of the conductive particles added is preferably 0.1 part 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.
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, and polycarboxylic acid metal. Complex particles, polyol metal complex particles, polymethylmethacrylate resin particles, polystyrene resin particles, melamine resin particles, phenol resin particles, nylon resin particles, silica particles, titanium oxide particles, alumina particles, etc. Can be mentioned. The amount of particles having charge controllability 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 triboelectric charge amount.

The toner used in combination with the magnetic carrier will be described.
The toner has toner particles and, if necessary, an external additive (inorganic fine particles). Further, the toner particles contain a binder resin (bonding resin of toner particles), and if necessary, a colorant and a mold release agent. Examples of the binder resin used for the toner particles include vinyl-based resin, polyester, and epoxy resin. Among these, vinyl-based resins and polyesters are preferable from the viewpoint of chargeability and fixability.
If necessary, homopolymers or copolymers of vinyl-based monomers, polyesters, polyurethanes, epoxy resins, polyvinyl butyral, rosin, modified rosins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, or fragrances. A group-based petroleum resin or the like can be mixed with the binder resin and used.

When two or more kinds of resins are mixed and used as a binder resin for toner particles, it is preferable to mix and use resins having different molecular weights.
The glass transition temperature of the binder resin is preferably 45 ° C. or higher and 80 ° C. or lower, and more preferably 55 ° C. or higher and 70 ° C. or lower.
The number average molecular weight (Mn) of the binder resin is preferably 2,500 or more and 50,000 or less.
The weight average molecular weight (Mw) of the binder resin is preferably 10,000 or more and 1,000,000 or less.

When polyester is used as the binder resin, polyester having 45 mol% or more and 55 mol% or less as an alcohol component and 55 mol% or less and 45 mol% or more as an acid component is preferable in all the components of the polyester.
The acid value of the polyester is preferably 90 mgKOH / g or less, and more preferably 50 mgKOH / g or less. The hydroxyl value of the polyester is preferably 50 mgKOH / g or less, and more preferably 30 mgKOH / g or less. This is because the smaller the number of terminal groups in the molecular chain of polyester, the smaller the environmental dependence of the charging characteristics of the toner tends to be.

The glass transition temperature of polyester is preferably 50 ° C. or higher and 75 ° C. or lower, and more preferably 55 ° C. or higher and 65 ° C. or lower.
The number average molecular weight (Mn) of the polyester is preferably 1,500 or more and 50,000 or less, and more preferably 2,000 or more and 20,000 or less.
The weight average molecular weight (Mw) of the polyester is preferably 6,000 or more and 100,000 or less, and more preferably 10,000 or more and 90,000 or less.

When a magnetic toner is used as the toner, the following can be mentioned as the magnetic material used for the magnetic toner. For example, iron oxides such as magnetite, maghemite, and ferrite, iron oxides including other metal oxides, metals such as Fe, Co, and Ni, and these metals and Al, Co, Cu, Pb, Mg, Ni, Sn. , Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, V and other alloys with metals, and mixtures thereof.

Examples of the non-magnetic colorant that can be used for the toner particles include the following.
Examples of the colorant for black toner include carbon black; those adjusted to black using a yellow colorant, a magenta colorant, and a cyan colorant.
Examples of the colorant for magenta toner include condensed azo compounds, diketopyrrolopyrrole compounds, anthracinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds and the like. ..
Specifically, C.I. 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: 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. I. Pigment Violet 19, C.I. I. Pigments such as Bat Red 1, 2, 10, 13, 15, 23, 29, 35 and the like can be mentioned.

Further, as a colorant for magenta toner, for example, C.I. I Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, C.I. I. Disperse thread 9, C.I. I. Solvent Violet 8, 13, 14, 21, 27, C.I. I. Oil-soluble dyes such as Disper Violet 1 and C.I. 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. I. Basic violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28 and other basic dyes can also be mentioned.
Examples of the colorant for cyan toner include C.I. I. Pigment Blue 1, 2, 3, 7, 15: 2, 15: 3, 15: 4, 16, 17, 60, 62, 66, C.I. I. Bat Blue 6, C.I. I. Examples thereof include acid blue 45 and pigments such as copper phthalocyanine pigments in which one or more and five or less phthalocyanine methyls are substituted in the phthalocyanine skeleton.

Examples of the colorant for yellow toner include pigments such as condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal compounds, methine compounds, and allylamide compounds. Specifically, C.I. 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, 191,
C. I. Bat Yellow 1, 3, 20 and the like can be mentioned.
Further, as a colorant for yellow toner, for example, C.I. I. Direct green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Dyes such as Solvent Yellow 162 can also be mentioned.

As the colorant, only the pigment may be used, or the pigment and the dye may be used in combination from the viewpoint of improving the sharpness and the image quality of the full-color image.
The content of the colorant is preferably 0.1 part by mass or more and 30 parts by mass or less, and preferably 0.5 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin of the toner particles. More preferred. More preferably, it is 3 parts by mass or more and 15 parts by mass or less.
Further, in the production of toner particles, it is preferable to use a binder resin mixed with a colorant in advance and made into a masterbatch (colorant masterbatch). Then, by melt-kneading the colorant masterbatch and other raw materials (binding resin, wax, etc.), the colorant can be satisfactorily dispersed in the toner particles.

The toner particles contained in the toner may contain a charge control agent, if necessary, in order to stabilize the chargeability.
The content of the charge control agent is preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin of the toner particles. If it is 0.5 parts by mass or more, more sufficient charging characteristics can be obtained. When it is 10 parts by mass or less, the compatibility with other materials is unlikely to decrease, and overcharging is unlikely to occur in a low humidity environment.

Examples of the load electrical control agent for controlling the toner particles to load electrical include an organometallic complex and a chelate compound. Specific examples thereof include monoazo metal complexes, aromatic hydroxycarboxylic acid metal complexes, and aromatic dicarboxylic acid-based metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids or aromatic polycarboxylic acids, their metal salts, their anhydrides, their esters, or bisphenol phenol derivatives. ..
Examples of the positive charge control agent for controlling the toner particles to be positive charge include a modified product of niglocin or a metal salt thereof, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, and tetrabutylammoniumtetrafluoro. Quadruple ammonium salts such as borate, onium salts such as phosphonium salts, triphenylmethane dyes, these lake pigments (as lake agents, phosphotung acid, phosphomolybdic acid, phosphotungene molybdic acid, tannic acid, lauric acid, etc. Diorganosin oxide such as dibutyltin oxide, dioctyltinoxide, dicyclohexyltinoxide, diorganotinborate such as dibutyltinborate, dioctyltinborate, dicyclohexyltinborate, etc. ..

The toner particles may contain one or more mold release agents, if necessary.
Examples of the mold release agent include low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and aliphatic hydrocarbon waxes such as paraffin wax.
The main component of the mold release agent is, for example, an oxide of an aliphatic hydrocarbon wax such as polyethylene oxide wax or a block copolymer thereof, and a fatty acid ester such as carnauba wax, sazole wax, and montanic acid ester wax. Examples thereof include waxes and fatty acid esters such as deoxidized carnauba wax, which are partially or wholly deoxidized.

The content of the release agent is preferably 0.1 part by mass or more and 20 parts by mass or less, and 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin of the toner particles. Is more preferable.
Further, the melting point defined by the maximum endothermic peak temperature at the time of temperature rise measured by the differential scanning calorimeter (DSC) of the release agent is preferably 65 ° C. or higher and 130 ° C. or lower, and 80 ° C. or higher and 125 ° C. The following is more preferable. When the melting point is 65 ° C. or higher, the viscosity of the toner is unlikely to decrease, and the toner is less likely to adhere to the electrophotographic photosensitive member. When the melting point is 130 ° C. or lower, sufficient low temperature fixability can be obtained.

The toner particles may contain crystalline polyester, if necessary.
The crystalline polyester is preferably obtained by polycondensation of an aliphatic diol having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 6 to 12 carbon atoms. The aliphatic diol and the aliphatic dicarboxylic acid are preferably saturated and preferably linear. The crystallinity means that a clear endothermic peak is observed in the reversible specific heat change curve of the specific heat change measurement by the differential scanning calorimeter (DSC).

An external additive (fluidity improver) may be externally added to the toner particles from the viewpoint of improving the fluidity.
Examples of the external additive include fluorine atom-containing resin particles such as vinylidene fluoride particles and polytetrafluoroethylene particles; silica particles such as wet-process silica particles and dry-process silica particles, and inorganic particles such as titanium oxide particles and alumina particles. Particles are mentioned. Inorganic particles are surface-treated with a silane coupling agent, titanium coupling agent, silicone oil, etc.
Hydrophobicized ones are preferable. Specifically, inorganic oxide particles treated so that the degree of hydrophobicity measured by the methanol titration test shows a value in the range of 30 or more and 80 or less are preferable.
The content of the external additive is preferably 0.1 part by mass or more and 10 parts by mass or less, and more preferably 0.2 parts by mass or more and 8 parts by mass or less with respect to 100 parts by mass of the toner particles.

The magnetic carrier of the present invention can be used as a two-component developer containing a binder resin, a toner having toner particles containing a colorant and a mold release agent if necessary, and a magnetic carrier. When the magnetic carrier is mixed with toner and used as a two-component developer, the toner content (toner concentration) in the two-component developer is preferably 2% by mass or more and 15% by mass or less. More preferably, it is 4% by mass or more and 13% by mass or less. If it is 2% by mass or more, the density of the output image is unlikely to decrease, and if it is 15% by mass or less, fog in the output image and toner scattering (in-flight scattering) in the image forming apparatus are unlikely to occur.

The two-component developer containing the magnetic carrier of the present invention has a charging step of charging an electrostatic latent image carrier, an electrostatic latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image carrier, and the like. A development step of developing the electrostatic latent image with a two-component developer to form a toner image, a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer body, and transfer. It can be used in an image forming method having a fixing step of fixing the toner image to the transfer material.
Further, in the image forming method, the developer has a two-component developer, and the replenishing developer is replenished to the developer according to the decrease in the toner concentration of the two-component developer in the developer. It may have such a configuration. The magnetic carrier of the present invention can be used as a supplementary developer for use in such an image forming method. The image forming method may have a configuration in which excess magnetic carriers in the developer are discharged from the developer as needed.

Further, the replenishing developer preferably contains a magnetic carrier, a binder resin, and a toner having toner particles containing a colorant and a mold release agent, if necessary. The replenishing developer preferably contains 2 parts by mass or more and 50 parts by mass or less of the toner particles with respect to 1 part by mass of the magnetic carrier. The replenishing developer does not have a replenishing magnetic carrier and may be only toner.

An image forming apparatus (electrophotographic apparatus) equipped with a developing apparatus using a two-component developer including a magnetic carrier and a supplementary developer will be described.
<Image formation method>
In FIG. 1, the electrophotographic photosensitive member 1 which is an electrostatic latent image carrier rotates in the direction of an arrow in FIG. The surface of the electrophotographic photosensitive member 1 is charged by a charging device 2 which is a charging means, and the surface of the charged electrophotographic photosensitive member 1 is charged by an image exposing device 3 which is an image exposing means (electrostatic latent image forming means). The image exposure light is applied to form an electrostatic latent image. The developer 4, which is a developing means, has a developing container 5 for accommodating a two-component developer.
The developer carrier 6 in the developer 4 is arranged in a rotatable state. The developer carrier 6 includes a magnet 7 as a magnetic field generating means inside the developer carrier 6. At least one of the magnets 7 is installed so as to face the electrophotographic photosensitive member 1. The two-component developer is held on the developer carrier 6 by the magnetic field of the magnet 7, the amount of the two-component developer is regulated by the regulating member 8, and is conveyed to the developing unit facing the electrophotographic photosensitive member 1. To. In the developing unit, a magnetic brush is formed by the magnetic field generated by the magnet 7.

After that, a development bias formed by superimposing an alternating electric field on a DC electric field is applied to the developer carrier, so that the electrostatic latent image is developed (visualized) as a toner image. The toner image formed on the surface of the electrophotographic photosensitive member 1 is electrostatically transferred to the recording medium (transfer material) 12 by the transfer charger 11 which is a transfer means.
Here, as shown in FIG. 2, the toner image is once transferred (primary transfer) from the electrophotographic photosensitive member 1 to the intermediate transfer body 9, and then electrostatically transferred (secondary transfer) to the recording medium 12. You may. After that, the recording medium 12 is conveyed to a fixing device 13 which is a fixing means, and is heated and pressurized there to fix the toner on the recording medium 12. After that, the recording medium 12 is discharged to the outside of the image forming apparatus as an output image.
After the transfer step, the toner (transfer residual toner) remaining on the surface of the electrophotographic photosensitive member 1 is removed by the cleaner 15 which is a cleaning means. After that, the surface of the electrophotographic photosensitive member 1 cleaned by the cleaner 15 is electrically initialized by being irradiated with the pre-exposure light from the pre-exposure device 16 which is the pre-exposure means, and the above image forming operation is performed. Is repeated.

FIG. 2 shows an example of a schematic diagram in which the image forming method of the present invention is applied to a full-color image forming apparatus.
In FIG. 2, K means black, Y means yellow, C means cyan, and M means magenta. In FIG. 2, the electrophotographic photosensitive members 1K, 1Y, 1C, and 1M rotate in the direction of the arrow in FIG. 2. The surfaces of the electrophotographic photosensitive members 1K, 1Y, 1C, and 1M for each color are charged by the charging means 2K, 2Y, 2C, and 2M, respectively. Image exposure light is applied to the surfaces of the charged electrophotographic photosensitive members 1K, 1Y, 1C, and 1M for each color by an image exposure device 3K, 3Y, 3C, and 3M, which are image exposure means (electrostatic latent image forming means), respectively. Is irradiated, and an electrostatic latent image is formed.
After that, the electrostatic latent image is made into toner by the two-component developer supported on the developer carriers 6K, 6Y, 6C, and 6M provided in the developing units 4K, 4Y, 4C, and 4M, which are the developing means. It is developed (visualized) as an image. The toner image is transferred (primary transfer) to the intermediate transfer body 9 by the primary transfer chargers 10K, 10Y, 10C, and 10M, which are the primary transfer means. Further, the toner image is transferred (secondary transfer) to the recording medium 12 by the secondary transfer charger 11 which is a secondary transfer means. After that, the recording medium 12 is conveyed to the fixing device 13 which is a fixing means, and is heated and pressurized to fix the toner on the recording medium 12.

After that, the recording medium 12 is discharged to the outside of the image forming apparatus as an output image. After the secondary transfer step, the intermediate transfer cleaner 14, which is a cleaning means for the intermediate transfer 9, removes transfer residual toner and the like. After the primary transfer step, the toner remaining on the surface of the electrophotographic photosensitive members 1K, 1Y, 1C and 1M is removed by the cleaners 15K, 15Y, 15C and 15M which are cleaning means.
As a development method using a two-component developer, an AC voltage is applied to the developer carrier to form an alternating electric field in the developing section, and the magnetic brush is in contact with the electrophotographic photosensitive member for development. It is preferable to do. The distance (distance between SD) between the developer carrier (developing sleeve (S)) 6 and the electrophotographic photosensitive member (photosensitive drum (D)) is 100 μm from the viewpoint of preventing carrier adhesion and improving dot reproducibility. It is preferably 1000 μm or more. If it is 100 μm or more, the two-component developer is sufficiently supplied, and the density of the output image is less likely to decrease. When it is 1000 μm or less, the magnetic field lines from the magnetic pole S1 are less likely to spread, the density of the magnetic brush is less likely to be lowered, and the dot reproducibility is less likely to be lowered. In addition, the force that restrains the magnetic carrier is less likely to weaken, and adhesion of the magnetic carrier is less likely to occur.

The voltage (Vpp) between the peaks of the alternating electric field is preferably 300 V or more and 3000 V or less, and more preferably 500 V or more and 1800 V or less. The frequency of the alternating electric field is preferably 500 Hz or more and 10000 Hz or less, and more preferably 1000 Hz or more and 7000 Hz or less. In this case, examples of the AC bias waveform for forming the alternating electric field include a triangular wave, a square wave, a sine wave, and a waveform having a different duty ratio. In order to cope with the change in the formation rate of the toner image, it is preferable to apply a development bias voltage (intermittent alternating superimposition voltage) having a discontinuous AC bias voltage to the developer carrier for development. When the applied voltage is 300 V or more, sufficient image density can be easily obtained, and fog toner in the non-image portion can be easily collected. Further, when the voltage is 3000 V or less, the electrostatic latent image is less likely to be disturbed by the magnetic brush.

By using a two-component developer having a well-charged toner, the fog removal voltage (Vback) can be lowered, and the primary charge of the electrophotographic photosensitive member can be lowered. The life can be extended. The Vback is preferably 200 V or less, more preferably 150 V or less. The contrast potential is preferably 100 V or more and 400 V or less so that sufficient image density can be obtained.
Further, if the frequency is 500 Hz or higher, an electrophotographic photosensitive member used in a normal image forming apparatus (electrophotograph apparatus) can be used. The electrophotographic photosensitive member has a structure in which a conductive layer, an undercoat layer, a charge generation layer, and a charge transport layer are provided in this order on a conductive support such as aluminum or SUS. Can be mentioned. If necessary, a protective layer may be provided on the charge transport layer.
As the conductive layer, the undercoat layer, the charge generation layer, and the charge transport layer, those usually used for an electrophotographic photosensitive member can be adopted.

<Measurement method of F1 and M1 by fluorescent X-ray diffraction method>
For the measurement of F1 and M1 of the magnetic carrier, the sample before resin coating is used. Alternatively, a resin-coated layer of the magnetic carrier after coating may be dissolved in chloroform and then dried.
Elements from Na to U in the magnetic material dispersion type resin carrier core material are directly measured in a He atmosphere using a wavelength dispersive fluorescent X-ray analyzer Axios advanced (manufactured by Spectris). Although the magnetic material-dispersed resin carrier core material also contains a resin component, since the element detected by fluorescent X-ray analysis is a metal, the ratio of F1 and M1 in the magnetic carrier is substantially the same. Is required.
For the sample, use the liquid sample cup attached to the device, put a PP (polypropylene) film on the bottom surface, put a sufficient amount (10 g) of the sample, form a uniform thick layer on the bottom surface, and cover it. The output is measured under the condition of 2.4 kW.
The FP (fundamental parameter) method is used for the analysis. At that time, it is assumed that all the detected elements are oxides, and their total mass is 100% by mass. The contents (% by mass) of F1 and M1 with respect to the total mass are obtained as an oxide conversion value by software UniQuant5 (ver. 5.49) (manufactured by Spectris).

<Measurement method of F2 and M2 by X-ray photoelectron spectroscopy>
Stick the magnetic carrier on the indium foil. At that time, the particles are evenly attached so that the indium foil portion is not exposed. The measurement conditions for X-ray photoelectron spectroscopy are as follows.
Equipment: PHI5000VERSAPROBE II (Albac Phi Co., Ltd.)
Irradiation line: Al Kd line output: 25W 15kV
Pass Energy: 29.35eV
Stepsize: 0.125eV
X-ray photoelectron spectroscopy peaks: Ti _2P , Al _2P , Mg _2P , Mn _2p , Ni _2p , Fe _2p
F2 and M2 are obtained by converting the element% calculated from each peak into mass%.

<Measuring method of volume average particle size (D50) of magnetic carrier and magnetic carrier core material>
The particle size distribution and the like were measured using a laser diffraction / scattering type particle size distribution measuring device (trade name: Microtrack MT3300EX, manufactured by Nikkiso Co., Ltd.).
The volume average particle size (D50) of the magnetic carrier and the magnetic carrier core material is measured by attaching a sample feeder for dry measurement (trade name: one-shot dry sample conditioner Turbotrac, manufactured by Nikkiso Co., Ltd.). rice field. As the supply conditions of Turbotrac, a dust collector was used as a vacuum source, the air volume was 33 l / sec, and the pressure was 17 kPa. The control was done automatically on the software. As the particle size, the 50% particle size (D50), which is the cumulative value of the volume average, was determined. Control and analysis were performed using the attached software (version 10.3.3-202D). The measurement conditions are as follows.
Set Zero time: 10 seconds Measurement time: 10 seconds Number of measurements: 1 particle Refractive index: 1.81%
Particle shape: Non-spherical Measurement upper limit: 1408 μm
Lower limit of measurement: 0.243 μm
Measurement environment: Temperature 23 ° C / Humidity 50% RH

<Measuring method of weight average particle size (D4) and number average particle size (D1) of toner>
The weight average particle size (D4) and the number average particle size (D1) of the toner are a precision particle size distribution measuring device (trade name: Coulter Counter Multisizer 3, Beckman Coulter) by the pore electric resistance method equipped with an aperture tube of 100 μm. (Manufactured by Beckman Coulter) and the attached dedicated software (trade name: Beckman Coulter Multisizer 3 Version 3.51, manufactured by Beckman Coulter) for setting measurement conditions and analyzing measurement data were used. The number of effective measurement channels was set to 25,000, and the measurement data was analyzed and calculated.
The electrolytic aqueous solution used for the measurement was prepared by dissolving special grade sodium chloride in ion-exchanged water so that the concentration became 1% by mass (trade name: ISOTON II, manufactured by Beckman Coulter).
Before performing the measurement and analysis, the dedicated software was set as follows.
In the dedicated software "Change standard measurement method (SOM) screen", set the total count number in the control mode to 50,000 particles, set the number of measurements to 1 time, and set the Kd value to "standard particles 10.0 μm" (Beckman Coulter). The value was set to the value obtained by using (manufactured by the company). By pressing the threshold / noise level measurement button, the threshold and noise level were automatically set. Further, the current was set to 1600 μA, the gain was set to 2, the electrolytic solution was set to “ISOTON II”, and the flash of the aperture tube after the measurement was checked.
In the "pulse to particle size conversion setting screen" of the dedicated software, the bin spacing was set to logarithmic particle size, the particle size bin was set to 256 particle size bins, and the particle size range was set from 2 μm to 60 μm.

The specific measurement method is as follows.
(1) 200 ml of the above electrolytic aqueous solution was placed in a 250 ml round bottom beaker made of glass exclusively for "Multisizer 3", set on a sample stand, and the stirrer rod was stirred counterclockwise at a rotation speed of 24 rpm. .. Dirt and air bubbles in the aperture tube were removed by the "Aperture Flash" function of the dedicated software.
(2) 30 ml of the above electrolytic aqueous solution was placed in a 100 ml flat bottom beaker made of glass. To this, 0.3 ml of a diluted solution of a dispersant (trade name: Contaminon N, manufactured by Wako Pure Chemical Industries, Ltd.) diluted 3-fold (mass ratio) with ion-exchanged water was added. "Contaminone N" is a 10% by mass aqueous solution of a neutral detergent for cleaning a precision measuring instrument having a pH of 7, which comprises a nonionic surfactant, an anionic surfactant, and an organic builder.
(3) Two oscillators with an oscillation frequency of 50 kHz are built in with the phase shifted by 180 degrees, and an ultrasonic disperser with an electrical output of 120 W (trade name: Ultrasonic Dispersion System Terra150, manufactured by Nikkei Bios Co., Ltd.) Ion-exchanged water was put into the water tank of. 2 ml of "Contaminone N" was added to this water tank.
(4) The beaker of (2) above was set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser was operated. Then, the height position of the beaker was adjusted so that the resonance state of the liquid level of the electrolytic solution in the beaker was maximized.
(5) With the electrolytic aqueous solution in the beaker of (4) above being irradiated with ultrasonic waves, 10 mg of toner was added little by little to the electrolytic aqueous solution and dispersed. Then, the ultrasonic dispersion processing was continued for 60 seconds. For ultrasonic dispersion, the water temperature in the water tank was adjusted to be 10 ° C. or higher and 40 ° C. or lower.
(6) The electrolytic aqueous solution of (5) above, in which toner was dispersed, was dropped onto the round bottom beaker of (1) above installed in the sample stand, and the measured concentration was adjusted to 5%. Then, the measurement was performed until the number of measured particles reached 50,000.
(7) The measurement data was analyzed by the above-mentioned dedicated software attached to the apparatus, and the weight average particle size (D4) and the number average particle size (D1) were calculated. The "average diameter" of the analysis / volume statistical value (arithmetic mean) screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4). The "average diameter" of the analysis / number statistical value (arithmetic mean) screen when the graph / number% is set by the dedicated software is the number average particle size (D1).

<Measurement method of acid value>
The acid value is the number of mg of potassium hydroxide required to neutralize the acid contained in 1 g of the sample. That is, the number of mg of potassium hydroxide required to neutralize free fatty acids and resin acids contained in 1 g of a sample is called an acid value.
In the present invention, the acid value is measured according to JIS K 0070-1992. Specifically, the measurement is performed according to the following procedure.
(1) Preparation of Reagents 1.0 g of phenolphthalein is dissolved in 90 mL of ethyl alcohol (95% by volume), and ion-exchanged water is added to make 100 mL to obtain a phenolphthalein solution.
Dissolve 7 g of special grade potassium hydroxide in 5 mL of water and add ethyl alcohol (95% by volume) to make 1 L. Put it in an alkali-resistant container so as not to touch carbon dioxide, leave it for 3 days, and then filter it to obtain a potassium hydroxide solution. The resulting potassium hydroxide solution is stored in an alkali resistant container. As for the factor of the potassium hydroxide solution, take 25 mL of 0.1 mol / L hydrochloric acid in a triangular flask, add a few drops of the phenolphthaline solution, titrate with the potassium hydroxide solution, and the hydroxylation required for neutralization. Obtained from the amount of potassium solution. As the 0.1 mol / L hydrochloric acid, those prepared according to JIS K 8001-1998 are used.
(2) Operation (A) 2.0 g of this test sample is precisely weighed in a 200 mL Erlenmeyer flask, 100 mL of a mixed solution of toluene / ethanol (2: 1) is added, and the mixture is dissolved over 5 hours. Then, a few drops of the phenolphthalein solution are added as an indicator, and titration is performed using the potassium hydroxide solution. The end point of the titration is when the light red color of the indicator continues for about 30 seconds.
(B) Blank test Titration is performed in the same manner as described above except that no sample is added (that is, only a mixed solution of toluene / ethanol (2: 1) is used).
(3) Calculation of acid value Substitute the obtained result into the following formula to calculate the acid value.
AV = [(BA) x f x 5.61] / S
Here, AV: acid value (mgKOH / g), A: addition amount of potassium hydroxide solution in blank test (mL), B: addition amount of potassium hydroxide solution in this test (mL), f: potassium hydroxide Solution factor, S: sample (g).

<Separation of the resin coating layer from the magnetic carrier and separation of the coating resins A and B in the resin coating layer>
As a method of separating the coating layer from the magnetic carrier, there is a method of taking the magnetic carrier in a cup and eluting the coating resin with toluene.
The eluted resin is separated using the following device.
[Device configuration]
LC-908 (manufactured by Nippon Analytical Industry Co., Ltd.)
JRS-86 (company; repeat injector)
JAR-2 (the company; autosampler)
FC-201 (Gilson; Fraction collector)
[Column structure]
JAIGEL-1H-5H (20φ x 600mm: preparative column) (manufactured by Nippon Analytical Industry Co., Ltd.)
[Measurement condition]
Temperature: 40 ° C
Solvent: THF
Flow rate: 5 ml / min.
Detector: RI
In the preparative method, the elution time at which the molecular weight distribution of the coating resin becomes the peak molecular weight (Mp) of the coating resin A and the coating resin B is measured in advance by the following method, and each resin component is preliminarily separated before and after that. do. After that, the solvent is removed and dried to obtain a coating resin A and a coating resin B. As for the resin composition, the atomic group is specified from the absorption wave number using a Fourier transform infrared spectroscopic analyzer (Spectrum One: manufactured by PerkinElmer), and the coating resin A and the coating resin B are specified.

<Measurement of peak molecular weight (Mp) and content ratio of coating resin A, coating resin B and coating resin in the resin coating layer>
The peak molecular weight (Mp) of the coating resin A, the coating resin B, and the coating resin was measured by the following procedure using gel permeation chromatography (GPC).
First, the measurement sample was prepared as follows.
A sample (coating resin separated from the magnetic carrier, coating resin A or coating resin B separated by a preparative device) and tetrahydrofuran (THF) are mixed at a concentration of 5 mg / ml, and the mixture is mixed at room temperature for 24 hours. The sample was allowed to stand and dissolved in THF. Then, a sample processed through a sample processing filter (Myshori Disc H-25-2 manufactured by Tosoh Co., Ltd., Ekikuro Disc 25CR manufactured by German Science Japan Co., Ltd.) was used as a GPC sample.
Next, a GPC measuring device (HLC-8120GPC manufactured by Tosoh Corporation) was used, and measurement was performed under the following measurement conditions according to the operation manual of the device.
(Measurement condition)
Equipment: High-speed GPC "HLC8120 GPC" (manufactured by Tosoh Corporation)
Column: 7 stations of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK)
Eluent: THF
Flow velocity: 1.0 ml / min
Oven temperature: 40.0 ° C
Sample injection amount: 0.10 ml
In calculating the peak molecular weight (Mp) of the sample, the calibration curve is a standard polystyrene resin (TSK standard polystyrene F-850, F-450, F-288, F-128, F-80, F-40 manufactured by Tosoh Corporation. , F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500).
The content ratio was determined by the peak area ratio of the molecular weight distribution measurement. As shown in FIG. 3, in the case where the region 1 and the region 2 are completely separated, the resin content ratio was obtained from the area ratio of each region. When the regions overlap as shown in FIG. 4, the GPC molecular weight distribution curve is divided by a line perpendicular to the horizontal axis from the inflection point, and the content ratio is calculated from the area ratio of the regions 1 and 2 shown in FIG. Asked.

<Measurement of the content of the resin coating layer in the magnetic carrier>
A A 100 ml beaker is precisely weighed (measured value 1), then about 5 g of the sample to be measured is put in, and the total mass of the sample and the beaker is precisely weighed (measured value 2).
B Put about 50 ml of toluene in a beaker and shake with an ultrasonic shaker for 5 minutes.
C After shaking, allow the sample to stand for several minutes, stir the sample in the beaker 20 times with a neodymium magnet so as to trace the bottom of the beaker, and then flow only the toluene solution in which the resin film is dissolved as a waste liquid.
While holding the sample in the D beaker from the outside with a neodymium magnet, put about 50 ml of toluene into the beaker again and repeat the above operations B and C 10 times.
E The solvent is changed to chloroform, and the above operations B and C are further performed once.
The entire F beaker is put into a vacuum dryer to dry and remove the solvent (a vacuum dryer with a solvent trap is used, the temperature is 50 ° C., the degree of vacuum is −0.093 MPa or less, and the drying time is 12 hours).
G Remove the beaker from the vacuum dryer, leave it for about 20 minutes to cool, and then weigh the mass (measured value 3).
H From the measured values obtained as described above, the resin coating amount (mass%) is calculated according to the following formula.
Resin coating amount = (initial sample mass-sample mass after coating peeling) / initial sample mass x 100
In the above formula, the initial sample mass is calculated by calculating (measured value 2-measured value 1), and the sample weight after film peeling is calculated by calculating (measured value 3-measured value 1).

<Measurement of specific resistivity (Ω · cm) of magnetic carrier at electric field strength 2000 V / cm>
The specific resistance at an electric field strength of 2000 V / cm is measured using the measuring device schematically shown in FIG.
The resistance measurement cell A is a cylindrical container (made of PTFE resin) 17 with a hole having a cross-sectional area of 2.4 cm ² , a lower electrode (made of stainless steel) 18, a support pedestal (made of PTFE resin) 19, and an upper electrode (made of stainless steel). It is composed of 20. A cylindrical container 18 is placed on a support pedestal 19, a sample (magnetic carrier or carrier core) 21 is filled to a thickness of about 1 mm, an upper electrode 20 is placed on the filled sample 21, and the thickness of the sample is measured. do. As shown in FIG. 5A, the gap when there is no sample is d1, and as shown in FIG. 5B, the gap d2 when the sample is filled so as to have a thickness of about 1 mm is used as the sample. The thickness d of is calculated by the following formula.
d = d2-d1 (mm)
At this time, the mass of the sample is appropriately changed so that the thickness d of the sample is 0.95 mm or more and 1.04 mm or less.
The resistivity of the sample can be obtained by applying a DC voltage between the electrodes and measuring the current flowing at that time. An electrometer 22 (Kesley 6517A, manufactured by Kessley) and a processing computer 23 for control are used for the measurement.
A control system and control software (LabVIEW National Instruments) manufactured by National Instruments Co., Ltd. were used as a processing computer for control.
As the measurement conditions, input the measured value d so that the contact area S between the sample and the electrode is 2.4 cm ² , and the thickness of the sample is 0.95 mm or more and 1.04 mm or less. Further, the load of the upper electrode is 270 g.
Specific resistance (Ω · cm) = (applied voltage (V) / measured current (A)) × S (cm ² ) / d (cm) Electric field strength (V / cm) = applied voltage (V) / d (cm)
For the specific resistance at the electric field strength of the magnetic carrier and the carrier core, the specific resistance at the electric field strength on the graph is read from the graph. As for the breakdown point, the measured value immediately before the breakdown is adopted in the obtained graph.

<Measurement method of true specific gravity of magnetic carrier>
The true specific gravity of the magnetic carrier is measured using a dry automatic densitometer auto pycnometer (manufactured by Yuasa Ionics Co., Ltd.).
Cell: SM cell (10 mL)
Sample amount: 2.0 g

<Method for measuring the average particle size of magnetic materials>
The number average particle diameter of the magnetic particles A and the magnetic particles B in the magnetic material dispersion type resin carrier core material is measured by the following procedure.
The cross section of the magnetic material dispersion type resin carrier core material cut by a microtome or the like is observed with a scanning electron microscope (50,000 times), and 100 particles having a particle diameter of 50 nm or more are randomly extracted. The major axis particle diameter of each extracted particle is calculated from the image, and the average value of 100 particle diameters is taken as the number average particle diameter.
When the magnetic particle B does not contain a manganese element, an aluminum element, a magnesium element, a titanium element or a nickel element, the magnetic particles A and B can be distinguished from each other by the following method in the cross section.
Using a scanning electron microscope (manufactured by Hitachi, Ltd., S4700 (trade name)), the magnetic component and the element of the resin component in the cross section of the magnetic material dispersion type resin carrier core material are attached to the scanning electron microscope. Analysis is performed using an analysis means (energy dispersive X-ray analyzer manufactured by EDAX).
Elemental analysis of one magnetic particle is performed while adjusting the magnification, and particles in which manganese element, aluminum element, magnesium element, titanium element or nickel element are detected in addition to iron element are defined as magnetic particle A. Magnetic particles B are defined as particles having only iron element or elements other than iron element and manganese element, aluminum element, magnesium element, titanium element, and nickel element, and non-magnetic particles in which iron element is not detected. Is defined as.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, the following parts and% are based on mass.

<Manufacturing example of amorphous magnetic particles>
Fe ₃ O ₄ was mixed and pulverized in a wet ball mill for 10 hours. One part of polyvinyl alcohol was added, and the mixture was granulated and dried with a spray dryer. Baking was carried out in an electric furnace at 900 ° C. for 10 hours under an atmosphere of 0.0% by volume nitrogen.
The obtained magnetic material was pulverized with a dry ball mill for 5 hours. The particles were classified by a wind power classifier (Elbow Jet Lab EJ-L3, manufactured by Nittetsu Mining Co., Ltd.), and fine powder and coarse powder were simultaneously classified and removed to obtain magnetic particles having a number average particle diameter of 1.7 μm. The average particle size was adjusted to an arbitrary number by adjusting the crushing time of the dry ball mill and the wind power classification conditions.

<Manufacturing example of spherical magnetic particles>
A ferrous sulfate aqueous solution containing 26.7 L of ^{Fe 2+ and} 1.5 mol / L and a silicic acid containing ^{Si 4+} 0.2 mol / L while agitating nitrogen gas at 20 L / min in a reaction vessel having a gas blowing tube. 1.0 L of a soda No. 3 aqueous solution was added to 22.3 L of a 3.4 N sodium hydroxide aqueous solution, and the pH was raised to 6.8 and the temperature was raised to 90 ° C. Further, 1.2 L of a 3.5 N aqueous sodium hydroxide solution was added, the pH was adjusted to 8.5, stirring was continued, the gas was changed to air, and the mixture was aerated at 100 L / min for 90 minutes. The particles were neutralized to pH 7 with dilute sulfuric acid, and the produced particles were washed with water, filtered, dried and pulverized to obtain spherical magnetic particles having a number average particle size of 0.25 μm. By changing the reaction temperature of the magnetic particles, the pH of the reaction field, and the reaction time, an arbitrary number average particle size was adjusted.

<Preparation of magnetic particles A>
A slurry 100 L containing 90 g / l of the above amorphous magnetic particles whose number average particle diameter was adjusted to 1.7 μm was adjusted to pH 8.5 by adding a sodium hydroxide solution at a temperature of 90 ° C., and then 2.5 mol / l sulfuric acid. 30 L of an aqueous manganese solution and an aqueous solution of sodium hydroxide were added over 190 minutes while adjusting the pH to 8.5 ± 0.2 at the same time. Then, after aging for 60 minutes, dilute sulfuric acid was added to adjust the pH to 7.0, and then the particles were filtered, washed with water and dried to obtain magnetic particles A surface-treated with Mn.
Further, the obtained magnetic particles A and a silane-based coupling agent (3- (2-aminoethylamino) propyltrimethoxysilane) (0.2 part with respect to 100 parts of the magnetic fine particles) were introduced into a container. .. Then, the surface was treated by high-speed mixing and stirring at 100 ° C. for 1 hour in the container to obtain magnetic particles A for the magnetic material dispersion type resin carrier core material (core material particles) 1.

(Magnetic Particle A for Magnetic Material Dispersion Type Resin Carrier Core Material (Core Material Particles) 2 to 25)
The shape and number average particle diameter of the magnetic particles were adjusted as shown in Table 1, and the following treatments were performed for each.
When the non-ferrous metal element was an aluminum element, aluminum sulfate was added in place of manganese sulfate at a ratio of 0.015% by mass / min or less with respect to the nuclear particles. After that, it was aged for 30 minutes or more, adjusted to pH, washed with water and dried according to a conventional method.
When the non-ferrous metal element is magnesium element, nickel element or titanium element, the pH of the slurry containing the nuclear particles is 10.0 for magnesium element, 7.8 for nickel element, and 8 for titanium element. Controlling to 0.7, each metal salt is added to the nuclei particles at 0.015% by weight / min or less, aged for 30 minutes or more, adjusted in pH, washed with water and dried according to a conventional method.
Further, the treatment amount was the same except that the addition amount of each element was adjusted, and magnetic particles A for the magnetic material dispersion type resin carrier core material (core material particles) 2 to 25 were obtained. Table 1 shows the prescriptions and the like.

<Preparation of magnetic particles B>
The shape and number average particle diameter of the magnetic particles were adjusted as shown in Table 1 to obtain magnetic particles.
The obtained magnetic particles and a silane-based coupling agent (3-glycidoxypropylmethyldimethoxysilane) (1.2 parts with respect to 100 parts of magnetite fine particles) were introduced into a container. Then, the surface was treated by high-speed mixing and stirring at 100 ° C. for 1 hour in the container to obtain magnetic particles B for the magnetic material dispersion type resin carrier core material (core material particles) 1.

(Magnetic particle B for magnetic material dispersion type resin carrier core material (core material particles) 2 to 25)
The shape and number average particle diameter of the magnetic material are adjusted as shown in Table 1, and when surface treatment is performed, the same treatment as for magnetic particle A is performed, and the magnetic material dispersion type resin carrier core material is used in the same manner. Magnetic particles B for (core material particles) 2 to 25 were obtained.
(Non-magnetic particles)
As the non-magnetic particles, commercially available particles having the number average particle diameter in Table 1 were used.

<Manufacturing example of magnetic material dispersion type resin carrier core material (core material particles) 1 to 25>
・ Phenol 10.0 parts ・ Formaldehyde solution (37% by mass aqueous solution of formaldehyde) 15.0 parts ・ Magnetic particles A 10.0 parts ・ Magnetic particles B 90.0 parts ・ 25% by mass ammonia water 3.5 parts ・ Water 15. 0 parts The above materials were introduced into a reaction vessel and mixed well at a temperature of 40 ° C. After that, the mixture was heated to a temperature of 85 ° C. at an average temperature rise rate of 1.5 ° C./min with stirring, maintained at a temperature of 85 ° C., and polymerized for 3 hours to cure. The peripheral speed of the stirring blade at this time was 1.96 m / sec.
After the polymerization reaction, the mixture was cooled to a temperature of 30 ° C. and water was added. The precipitate obtained by removing the supernatant was washed with water and further air-dried. The obtained air-dried product is subjected to reduced pressure (5 mmHg or less), 1
The mixture was dried at 80 ° C. for 5 hours to obtain a magnetic material-dispersed resin carrier core material 1 (hereinafter referred to as core material particles 1) which is a magnetic material-dispersed resin particles.
Similarly, magnetic core material particles 2 to 25 were obtained in the same manner as in the production example of core material particles 1 except that magnetic particles A, magnetic particles B, and non-magnetic particles were used in the types and ratios shown in Table 1. ..

<Production example of coating resin A>
The raw materials shown in Table 2 are added to a four-necked flask equipped with a reflux condenser, a thermometer, a nitrogen suction tube and a ground-glass stirrer, and further, 100 parts of toluene, 100 parts of methyl ethyl ketone, and azobisisovaleronitrile 2. 4 parts were added and kept at 80 ° C. for 10 hours under a nitrogen stream to obtain a coating resin A-1 solution (solid content 35%).
Further, using the raw materials shown in Table 2, coating resins A-2 to A-5 were obtained in the same manner. The physical characteristics are shown in Table 2.

<Production example of coating resin B>
The raw materials shown in Table 3 are added to a four-necked flask equipped with a reflux condenser, a thermometer, a nitrogen suction tube and a ground-glass stirrer, and further, 50 parts of toluene, 100 parts of methyl ethyl ketone, and azobisisovaleronitrile 2. 4 parts were added and kept at 80 ° C. for 10 hours under a nitrogen stream to obtain a coating resin B-1 solution (solid content 40%).
Further, using the raw materials shown in Table 3, coating resins B-2 and B-3 were obtained in the same manner. The physical characteristics are shown in Table 3.

<Production examples of coating resin solutions 1 to 8>
The coating resin A and the coating resin B shown in Tables 2 and 3 were mixed by parts by mass shown in Table 4. Subsequently, 900 parts of toluene was added to 100 parts of the total amount of the resin component and mixed until the resin component was sufficiently melted to prepare coating resin solutions 1 to 8.

<Manufacturing examples of magnetic carriers 1 to 25>
The content of the resin coating layer with respect to 100 parts by mass of the core material particles 1 (100.0 parts) and the coating resin solution diluted with toluene so that the solid content ratio becomes 10% is shown in Table 5. It was put into a planetary motion type mixer (Nautamixer VN type manufactured by Hosokawa Micron Co., Ltd.) maintained at a temperature of 60 ° C. under reduced pressure (1.5 kPa) so as to have a "coating amount".
As a method of charging, first, 1/2 amount of the resin solution was charged to the core material particles, and the solvent was removed and the coating operation was performed for 30 minutes. Then, a further 1/2 amount of the resin solution was added, and the solvent was removed and the coating operation was performed for 30 minutes.
After that, the magnetic carrier coated with the coated resin composition was transferred to a mixer (drum mixer UD-AT type manufactured by Sugiyama Heavy Industries, Ltd.) having spiral blades in a rotatable mixing container. The mixing vessel was rotated 10 times per minute and heat-treated at a temperature of 120 ° C. for 2 hours under a nitrogen atmosphere. The obtained magnetic carrier was separated into low magnetic force products by magnetic beneficiation, passed through a sieve having an opening of 150 μm, and then classified by a wind power classifier to obtain magnetic carrier 1.
For the core material particles 2 to 25, a coating resin solution was used so that the content of the resin coating layer with respect to 100 parts of the core material particles was the “coating amount” in Table 5, in the same manner as in the magnetic carrier 1. , Magnetic carriers 2 to 25 were obtained. Table 5 shows the physical property values of the obtained magnetic carriers 1 to 25.

表中、処理量は、磁性粒子Ａ又は磁性粒子Ｂ中の、各金属の質量％を示す。粒径はμｍを示す。

In the table, the processing amount indicates the mass% of each metal in the magnetic particles A or the magnetic particles B. The particle size indicates μm.

表中、比抵抗は電界強度２０００Ｖ／ｃｍにおける値である。

In the table, the resistivity is a value at an electric field strength of 2000 V / cm.

[Manufacturing example of cyan toner]
Biding resin (Tg 62 ° C, acid value 15 mgKOH / g, hydroxyl value 15 mgKOH / g polyester (composition: polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 45 parts, polyoxy Ethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 5 parts, terephthalic acid 20 parts, trimellitic anhydride 2 parts, fumaric acid 28 parts))
100 copies ・ C. I. Pigment Blue 15: 3 5.5 parts ・ 3,5-di-t-Aluminum salicylate compound 0.5 parts ・ Normal paraffin wax (melting point: 78 ° C) 6 parts Henshell mixer (FM- After mixing well in 75J type, manufactured by Mitsui Mine Co., Ltd., feed amount of 10 kg / hr with a twin-screw kneader (trade name: PCM-30 type, manufactured by Ikegai Steel Co., Ltd.) set at a temperature of 130 ° C. (The temperature of the kneaded product at the time of discharge was 150 ° C.). The obtained kneaded product was cooled, coarsely crushed with a hammer mill, and then finely pulverized with a mechanical crusher (trade name: T-250, manufactured by Turbo Industries, Ltd.) at a feed amount of 15 kg / hr. Then, a particle having a weight average particle size of 5.5 μm, containing 55.6% by volume of particles having a particle size of 4.0 μm or less and 0.8% by volume of particles having a particle size of 10.0 μm or more was obtained. ..
The obtained particles were classified by a rotary classifier (trade name: TTSP100, manufactured by Hosokawa Micron Co., Ltd.) to cut fine powder and coarse powder. Cyan has a weight average particle size of 6.4 μm, an abundance rate of particles having a particle size of 4.0 μm or less is 25.8 number%, and an abundance rate of particles having a particle size of 10.0 μm or more is 2.5% by volume. Toner particles 1 were obtained.
Furthermore, the following materials were put into a Henshell mixer (trade name: FM-75 type, manufactured by Nippon Coke Industries Co., Ltd.), the peripheral speed of the rotary blades was set to 35.0 (m / sec), and the mixing time was 3 minutes. By doing so, silica particles and titanium oxide particles were adhered to the surface of the cyan toner particles 1 to obtain cyan toner 1.
-Cyanner particles 1: 100 parts-Silica particles (silica particles prepared by the sol-gel method, surface-treated with 1.5% hexamethyldisilazane, and then adjusted to the desired particle size distribution by classification): 3.5 parts -Titanium oxide particles (methatitanic acid having anatase-type crystalline properties surface-treated with an octylsilane compound): 0.5 part

<Examples 1 to 17 (Example 15 is referred to as reference example 15) , Comparative Examples 1 to 8>
To 90 parts of the magnetic carrier 1, 10 parts of cyan toner was added and shaken with a shaker (YS-8D type: manufactured by Yayoi Co., Ltd.) to prepare a two-component developer. The amplitude condition of the shaker was 200 rpm for 2 minutes.
The following evaluation was performed using this two-component developer.
As an image forming apparatus, a color copier manufactured by Canon Inc. (trade name: iR-ADV C3)
A modified machine of 50F) was used.
A two-component developer was put in each color developer, a container for a replenishing developer containing a replenishing developer was set, an image was formed, and various evaluations were performed.
Environmental evaluation with a copier is: temperature 23 ° C / humidity 50% RH (hereinafter, N / N), temperature 23 ° C / humidity 5% RH (hereinafter, N / L), temperature 30 ° C / humidity 80% RH (hereinafter, N / N). , H / H). The type of output image and the number of output images were changed according to each evaluation item.
The conditions are as follows.
Paper: Laser beam printer paper (Product name: CS-814 (81.4 g / m ² , manufactured by Canon Marketing Japan Inc.))
Image formation speed: A4 size paper was modified to output at 35 sheets / minute in full color.
Development conditions: The development contrast can be adjusted by any value, and it has been modified so that the automatic correction by the main unit does not work.
Each evaluation item is shown below.

(1) N / L environment, image area ratio 1% Concentration stability after continuous image paper transfer (evaluation V)
In an N / L environment, three images having eight patches (1 cm × 1 cm) set to the following densities in an A4 size image are output. Next, 1000 images with an image area ratio of 1% are output in the N / L environment state, and then 3 images having 8 patches are output in the same manner. The image density is measured by an X-Rite color reflection densitometer (Color reflection densitometer X-Rite 404A), and the average value of each pattern of the three images output before and after 1000 sheets of continuous printing is calculated.
Patch 1: 0.10 to 0.15
Patch 2: 0.25 to 0.30
Patch 3: 0.45-0.50
Patch 4: 0.65-0.70
Patch 5: 0.85-0.90
Patch 6: 1.05-1.10
Patch 7: 1.25 to 1.30
Patch 8: 1.45 to 1.50
The number of patch density deviations before and after 1000 sheets of continuous paper is evaluated according to the following criteria.
A (10 points): All pattern images satisfy the above density range B (9 points): One pattern image deviates from the above density range C (8 points): Two pattern images are described above D (7 points) out of the density range: 3 pattern images out of the above density range E (6 points): 4 pattern images out of the above density range F (5 points): 5 patterns Image deviates from the above density range G (4 points): 6 pattern images deviate from the above density range H (3 points): 7 pattern images deviate from the above density range I (2 points): All pattern images are out of the above density range

(2) H / H environment, image area ratio 20% Concentration stability after continuous image paper transfer (evaluation W)
In an H / H environment, three images having eight patches (1 cm × 1 cm) set to the following densities in an A4 size image are output. Next, in an H / H environment, 1000 images and a solid image having an image area ratio of 20% are output, and then 3 images having 8 patches are output in the same manner. The image density is measured by an X-Rite color reflection densitometer (Color reflection densitometer X-Rite 404A), and the average value of each pattern of the three images output before and after 1000 sheets of continuous printing is calculated.
Patch 1: 0.10 to 0.15
Patch 2: 0.25 to 0.30
Patch 3: 0.45-0.50
Patch 4: 0.65-0.70
Patch 5: 0.85-0.90
Patch 6: 1.05-1.10
Patch 7: 1.25 to 1.30
Patch 8: 1.45 to 1.50
The number of patch density deviations before and after 1000 sheets of continuous paper is evaluated according to the following criteria.
A (10 points): All pattern images satisfy the above density range B (9 points): One pattern image deviates from the above density range C (8 points): Two pattern images are described above D (7 points) out of the density range: 3 pattern images out of the above density range E (6 points): 4 pattern images out of the above density range F (5 points): 5 patterns Image deviates from the above density range G (4 points): 6 pattern images deviate from the above density range H (3 points): 7 pattern images deviate from the above density range I (2 points): All pattern images are out of the above density range

(3) In-plane uniformity of image density (evaluation X)
After outputting 1000 solid images with an image area ratio of 20% in an H / H environment, one FFH output chart (A4 full-scale solid image) with an image ratio of 100% was output.
The image density was measured and evaluated with a spectrodensitometer 500 series (manufactured by X-Rite). The measurement site is
Three points, 5.0 cm, 15.0 cm, and 25.0 cm from the left edge of the image (the one printed first is on the upper side) at a position 0.5 cm from the tip of the image (the one printed first).
At a position 7.0 cm from the tip of the image, three points of 5.0 cm, 15.0 cm, and 25.0 cm from the left edge of the image,
At a position 14.0 cm from the tip of the image, three points of 5.0 cm, 15.0 cm, and 25.0 cm from the left edge of the image,
At a position 20.0 cm from the tip of the image, a total of 12 points of 5.0 cm, 15.0 cm, and 25.0 cm from the left end of the image were set, and the difference between the highest image density and the lowest image density was obtained. In addition, the one with the largest concentration difference among the 50 sheets was used as the evaluation result. The difference in image density was evaluated according to the following criteria.
A (10 points): Less than 0.04 B (9 points): 0.04 or more and 0.06 or less C (8 points): 0.07 or more and 0.09 or less D (7 points): 0.10 or more and 0. 12 or less E (6 points): 0.13 or more and 0.15 or less F (5 points): 0.16 or more and 0.18 or less G (4 points): 0.19 or more and 0.21 or less H (3 points): 0.22 or more and 0.24 or less I (2 points): 0.25 or more

(4) White spots (evaluation Y)
A chart in which halftone horizontal bands (30H width 10 mm) and solid black horizontal bands (FFH width 10 mm) are alternately arranged in the initial and immediately after 2000 sheets of continuous paper in an N / L environment and in the transfer direction of the transfer paper. Is output. The image is read by a scanner and binarized. The luminance distribution (256 gradations) of a certain line in the transport direction of the binarized image was taken. A tangent line is drawn on the brightness of the halftone at that time, and the area of brightness (area: sum of the number of brightness) deviated from the tangent line at the rear end of the halftone part until it intersects with the solid part brightness is defined as the degree of whiteout, and the following criteria are used. Evaluated based on. The evaluation was performed with a single cyan color.
A (5 points): 19 or less B (4 points): 20 or more 29 or less C (3 points): 30 or more 39 or less D (2 points): 40 or more 49 or less E (1 point): 50 or more

(5) Leakage evaluation (evaluation Z)
The initial Vpp was modified so that it could be manually changed to 1.50 kV under the N / L environment, and the contrast potential was set when the density of the cyan monochromatic solid image became 1.50 (reflection density). Do paper.
After passing the paper, set the contrast potential when the density of the cyan monochromatic solid image becomes 1.50 (reflection density) again, and set the Vpp at that contrast from 1.0 kV to 1.8 kV in 0.1 kV increments, A4. A full-size FFH image was output and a leak property evaluation was performed.

The evaluation was made according to the following criteria based on the value of Vpp in which three or more image defects such as white spots occur on the A4 full-size FFH image.
A (5 points): No occurrence even at 1.8 kV B (4 points): Generated at 1.8 kV C (3 points): Generated at 1.7 kV D (2 points): Generated at 1.6 kV E (1 point) : Occurs at 1.5 kV or less

(6) Comprehensive judgment The evaluation ranks in the evaluation Z were quantified from the above evaluation V, and the total value was used for judgment based on the following criteria.
A: 37 or more and 40 or less B: 32 or more and 36 or less C: 29 or more and 31 or less D: 20 or more and 28 or less E: 15 or more and 19 or less F: 14 or less The evaluation results are shown in Tables 6 and 7.

1,1K, 1Y, 1C, 1M: Electrophotographic photoconductor (electrostatic latent image carrier), 2, 2K, 2Y, 2C, 2M: Charger, 3, 3K, 3Y, 3C, 3M: Image exposure device, 4, 4K, 4Y, 4C, 4M: Developer, 5: Develop container, 6, 6K, 6Y, 6C, 6M: Developer carrier, 7: Magnet, 8: Regulator, 9: Intermediate transfer, 10K, 10Y, 10C, 10M: Primary transfer charger, 11: Transfer charger, 12: Recording medium (transfer material), 13: Fixer, 14: Intermediate transfer body cleaner, 15, 15K, 15Y, 15C, 15M: Cleaner, 16: Pre-exposure device 17: Cylindrical container, 18: Lower electrode, 19: Support pedestal, 20: Upper electrode, 21: Sample

Claims (16)

A magnetic carrier having a magnetic material-dispersed resin carrier core material and magnetic carrier particles having a resin coating layer formed on the magnetic material-dispersed resin carrier core material.
The magnetic material dispersion type resin carrier core material is
The number of primary particles contains magnetic particles A having an average particle diameter of ra (μm) and magnetic particles B having an average number of primary particles of rb (μm).
The ra and the rb is, satisfy the relationship of ra> rb,
The magnetic particles A contain an oxide of at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element, and iron oxide.
In the measurement of the magnetic carrier particles by the fluorescent X-ray diffractometry, when the total content of the non-ferrous metal element is M1 (mass%) and the content of the iron element is F1 (mass%), the ratio of M1 to F1. The value (M1 / F1) of is 0.010 or more and 0.100 or less.
In the measurement of the magnetic carrier particles by X-ray photoelectron spectroscopy, when the total content of the non-iron metal element is M2 (mass%) and the content of the iron element is F2 (mass%), it is relative to F2 of M2. A magnetic carrier having a ratio value (M2 / F2) of 1.0 or more and 10.0 or less. The number average particle diameter ra (μm) of the primary particles of the magnetic particles A is 0.30 μm or more and 3.00 μm or less.
The magnetic carrier according to claim 1, wherein the number average particle diameter rb (μm) of the primary particles of the magnetic particles B is 0.10 μm or more and 2.50 μm or less. The magnetic carrier according to claim 1 or 2, wherein the M2 / F2 is 1.5 or more and 8.5 or less. The magnetic carrier according to any one of claims 1 to 3, wherein the M2 / F2 is 1.8 or more and 6.0 or less. The magnetic carrier according to any one of claims 1 to 4, wherein the sum (M2 + F2) of the M2 (mass%) and the F2 (mass%) is 1.0% or more and 5.0% or less. The invention according to any one of claims 1 to 5, wherein the resin coating layer contains at least a copolymer of a (meth) acrylic acid ester having an alicyclic hydrocarbon group and another (meth) acrylic monomer. Magnetic carrier. The resin coating layer is
i) A copolymer of (meth) acrylic acid ester having an alicyclic hydrocarbon group and other (meth) acrylic monomers, coated with an acid value of 0.0 mgKOH / g or more and 3.0 mgKOH / g or less. Resin A and
ii) A polymer of a monomer containing at least other (meth) acrylic monomers, and a coating resin B having an acid value of 3.5 mgKOH / g or more and 50.0 mgKOH / g or less.
The magnetic carrier according to any one of claims 1 to 5. The magnetic carrier according to any one of claims 1 to 7, wherein the true specific gravity of the magnetic carrier is 2.5 or more and 4.4 or less. The invention according to any one of claims 1 to 8, wherein the specific resistance of the magnetic carrier at an electric field strength of 2000 (V / cm) is 1 × 10 ⁶ (Ω · cm) or more and 1 × 10 ^{12 (Ω · cm) or less.} The magnetic carrier described. The magnetic particles A are magnetite particles coated with the non-ferrous metal element.
The magnetic carrier according to any one of claims 1 to 9, wherein the magnetic particles B are magnetite particles not coated with the non-ferrous metal element. A two-component developer containing a toner having toner particles containing a binder resin and a magnetic carrier.
A two-component developer in which the magnetic carrier is the magnetic carrier according to any one of claims 1 to 10. Charging process for charging the electrostatic latent image carrier,
An electrostatic latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image carrier,
A developing step of developing the electrostatic latent image with a two-component developer to form a toner image.
An image forming method comprising a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer body, and a fixing step of fixing the transferred toner image to the transfer material.
The image forming method in which the two-component developer is the two-component developer according to claim 11. Charging process for charging the electrostatic latent image carrier,
An electrostatic latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image carrier,
A developing process in which the electrostatic latent image is developed using a two-component developer in a developer to form a toner image.
It has a transfer step of transferring the toner image to the transfer material with or without an intermediate transfer body, and a fixing step of fixing the transferred toner image to the transfer material.
A replenishing developer for use in an image forming method in which a replenishing developer is replenished to the developer in response to a decrease in the toner concentration of the two-component developer in the developing device.
The replenishing developer contains a magnetic carrier and a toner having toner particles containing a binder resin.
The replenishing developer contains 2 parts by mass or more and 50 parts by mass or less of the toner with respect to 1 part by mass of the magnetic carrier.
The magnetic carrier is a replenishing developer which is the magnetic carrier according to any one of claims 1 to 10. Charging process for charging the electrostatic latent image carrier,
An electrostatic latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image carrier,
A developing process in which the electrostatic latent image is developed using a two-component developer in a developer to form a toner image.
It has a transfer step of transferring the toner image to the transfer material with or without an intermediate transfer body, and a fixing step of fixing the transferred toner image to the transfer material.
This is an image forming method in which a replenishing developer is replenished to the developer in response to a decrease in the toner concentration of the two-component developer in the developing device.
The replenishing developer contains a magnetic carrier and a toner having toner particles containing a binder resin.
The replenishing developer contains 2 parts by mass or more and 50 parts by mass or less of the toner with respect to 1 part by mass of the magnetic carrier.
The image forming method, wherein the magnetic carrier is the magnetic carrier according to any one of claims 1 to 10. A method for manufacturing a magnetic carrier having magnetic carrier particles.
Magnetic particles A, magnetic particles B, basic catalysts, phenols, aldehydes and an aqueous medium are mixed and heated with stirring to react the phenols with the aldehydes, and the magnetism is contained in the phenol resin. A step of manufacturing a magnetic material-dispersed resin carrier core material in which the particles A and the magnetic particles B are dispersed, and
It has a step of forming a resin coating layer on the surface of the magnetic material dispersion type resin carrier core material and obtaining magnetic carrier particles.
When the number average particle diameter of the primary particles of the magnetic particles A is ra (μm) and the number average particle diameter of the primary particles of the magnetic particles B is rb (μm), the ra and the rb are ra> rb. Meet the relationship,
The magnetic particles A contain an oxide of at least one non-ferrous metal element selected from the group consisting of a manganese element, an aluminum element, a magnesium element, a titanium element, and a nickel element, and iron oxide.
In the measurement of the magnetic carrier particles by the fluorescent X-ray diffractometry, when the total content of the non-ferrous metal element is M1 (mass%) and the content of the iron element is F1 (mass%), the ratio of M1 to F1. The value (M1 / F1) of is 0.010 or more and 0.100 or less.
In the measurement of the magnetic carrier particles by X-ray photoelectron spectroscopy, when the total content of the non-iron metal element is M2 (mass%) and the content of the iron element is F2 (mass%), it is relative to F2 of M2. A method for producing a magnetic carrier, wherein the ratio value (M2 / F2) is 1.0 or more and 10.0 or less. The magnetic particles A are magnetite particles coated with the non-ferrous metal element.
The method for producing a magnetic carrier according to claim 15, wherein the magnetic particles B are magnetite particles not coated with the non-ferrous metal element.

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