JP6659145B2 - Magnetic carrier, two-component developer, replenishing developer, and image forming method - Google Patents

Description

  The present invention relates to a magnetic carrier, a two-component developer, a replenishing developer used in an image forming method for visualizing an electrostatic image using an electrophotographic method, and an image forming method using the same. It is.

2. Description of the Related Art Conventionally, in an electrophotographic image forming method, an electrostatic latent image is formed on an electrostatic latent image carrier using various means, and toner is attached to the electrostatic latent image to form an electrostatic latent image. Is generally used. At the time of the development, carrier particles called magnetic carriers are mixed with the toner and triboelectrically charged to impart an appropriate amount of positive or negative charge to the toner. A two-component developing method is widely used in which a product of the electric charge and an electric field formed in a developing area is used as a driving force to cause toner to fly on an electrostatic latent image carrier and develop the toner.
The two-component developing method can impart functions such as stirring, transporting, and charging of the developer to the magnetic carrier, so that the function sharing with the toner is clear, and therefore, there are advantages such as good controllability of the developer performance. There is.

On the other hand, in recent years, due to technological advances in the field of electrophotography, there has been an increasingly strict demand for not only high-speed and long-life devices but also high definition and stable image quality. In order to meet such demands, magnetic carriers have been required to have higher performance.
As one of the techniques, a technique has been proposed in which a sufficient image density can be ensured, carrier adhesion does not occur for a long period of time, and high-quality image quality can be maintained (Patent Document 1). Such a magnetic carrier is characterized in that the porosity of the core material is kept constant and the amount of resin filled in the voids is within a specific range.

  Further, a technique has been proposed in which an intermediate resin layer has at least one metal oxide of aluminum, magnesium, zinc and lead, and a monomer having a hydroxy group and a carboxyl group is copolymerized in the outermost coating resin layer. (Patent Document 2). Thereby, the negative charge maintaining property is improved, the coating film strength is strong, the peeling of the coating resin is suppressed, and the service life is extended.

Although these problems have been solved by these techniques, the resin coating layer has become uneven due to the surface properties of the core material. As a result, a thin portion of the resin coating layer serves as a charge injection site, causing an image problem such as a leak and a reduction in roughness (dot reproducibility), and further improvement is required for higher image quality.
Under such circumstances, a magnetic carrier having a long service life has been proposed, in which a carrier resin coating layer is formed uniformly, has good charge-imparting ability to toner, and has excellent charge retention characteristics. (See Patent Document 3).

JP 2006-337579 A JP-A-8-6309 JP 2007-183592 A

  However, in recent years, the burden on the developer in the developing device tends to increase, for example, the developer capacity is reduced due to the downsizing of the developing device, and the developer stirring speed is increased by increasing the output speed. As a result, especially in a high-temperature and high-humidity environment, due to the water cross-linking force acting between the magnetic carrier and the toner, the spent of the toner and the external additive progresses on the surface of the magnetic carrier, and the charging ability of the magnetic carrier is reduced. Reduce. In addition, the adsorption of moisture to the surface of the magnetic carrier proceeds, and the strength of the magnetic carrier resin coating layer temporarily decreases. As a result, peeling and scraping of the magnetic carrier resin coating layer occur, causing a problem that charging ability is reduced. A magnetic carrier, a two-component developer, a replenishing developer, and an image using the same that satisfy these problems are caused. The development of forming methods became urgent.

  An object of the present invention is to provide a magnetic carrier which solves the above problems. Specifically, even when used in a high-temperature, high-humidity environment for a long period of time, it is advantageous for shaving and peeling of the film, maintains a stable charge-providing ability, and changes from a high-temperature, high-humidity environment to a normal temperature, low-humidity environment Another object of the present invention is to provide a magnetic carrier having improved image density and color stability. Another object of the present invention is to provide a two-component developer and a replenishing developer containing such a magnetic carrier and an image forming method using the same.

In order to achieve the above object, the present invention provides
Porous magnetic particles, filled magnetic core particles having a filler present in the pores of the porous magnetic particles, and a resin coating layer present on the surface of the filled magnetic core particles,
A magnetic carrier having
The filler is
(I) a resin;
(Ii) oxide particles of a metal element having an ester group and / or a carboxyl group on the surface, silica particles having an ester group and / or a carboxyl group on the surface , and carbon black having an ester group and / or a carboxyl group on the surface. is selected from the group consisting of containing and one or more kinds of particles child,
The particles (ii) have a methanol wettability of 49 to 78% and a functional group concentration of the ester group and / or the carboxyl group of 20 to 71%.
A magnetic carrier characterized by the above.

  Further, the present invention is a two-component developer containing a toner having toner particles containing a binder resin, a colorant and a release agent, and a magnetic carrier. About.

  The present invention also provides a charging step of 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, and Developing using a component-based developer, a developing step of forming a toner image, a transferring step of transferring the toner image to a transfer material with or without an intermediate transfer member, and transferring the transferred toner image to the transfer material. The present invention relates to an image forming method including an image forming method having a fixing step of fixing to a transfer material.

The present invention also provides a charging step of 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, and a developing device for developing the electrostatic latent image. Developing using a two-component developer in the, a developing step of forming a toner image, a transferring step of transferring the toner image to a transfer material with or without an intermediate transfer member, and transferring the transferred toner image A fixing step of fixing to the transfer material, wherein a replenishing developer is replenished to the developing device in accordance with a decrease in the toner concentration of the two-component developer in the developing device, and the excess magnetic material is developed in the developing device. A replenishing developer for use in an image forming method in which a carrier is discharged from a developing device as needed,
The replenishment developer contains a replenishment magnetic carrier, a toner having toner particles containing a binder resin, a colorant and a release agent,
The replenishing developer relates to a replenishing developer, wherein the replenishing developer contains the toner in an amount of 2 parts by mass or more and 50 parts by mass or less based on 1 part by mass of the replenishing magnetic carrier.

The present invention also provides a charging step of 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, and a developing device for developing the electrostatic latent image. Developing using a two-component developer in the, a developing step of forming a toner image, a transferring step of transferring the toner image to a transfer material with or without an intermediate transfer member, and transferring the transferred toner image A fixing step of fixing to the transfer material, wherein a replenishing developer is replenished to the developing device in accordance with a decrease in the toner concentration of the two-component developer in the developing device, and the excess magnetic material is developed in the developing device. An image forming method in which a carrier is discharged from a developing device as needed,
The replenishment developer contains a replenishment magnetic carrier and a binder resin, a toner having toner particles containing a colorant and a release agent,
The image forming method according to claim 1, wherein the replenishing developer contains 2 to 50 parts by mass of the toner based on 1 part by mass of the replenishing magnetic carrier.

  By using the carrier of the present invention, even when used for a long time in a high-temperature and high-humidity environment, it is advantageous for shaving and peeling of the coating film, maintaining a stable charge-giving ability, and changing from a high-temperature and high-humidity environment to a normal temperature and low humidity environment. A magnetic carrier having improved image density and color stability can be obtained. Further, a two-component developer and a replenishing developer containing such a magnetic carrier and an image forming method using the same can be provided.

FIG. 1 is a schematic diagram of an image forming apparatus used in the present invention. FIG. 1 is a schematic diagram of an image forming apparatus used in the present invention. It is a schematic sectional drawing of the apparatus which measures the specific resistance of a magnetic core. FIG. 2 is a schematic view of a magnetic carrier of the present invention.

Hereinafter, embodiments of the present invention will be described.
<Carrier>
As shown in FIG. 4, the magnetic carrier 40 of the present invention comprises:
Filled magnetic core particles 43 having porous magnetic particles 41 and a filler 42 present in pores of the porous magnetic particles, and a resin coating layer 44 present on the surface of the filled magnetic core particles 43. A magnetic carrier 40 having
The filler 42 is
(I) resin 45;
(Ii) One or two or more hydrophilically-treated particles selected from the group consisting of hydrophilically-treated metal oxide particles, hydrophilically-treated silica particles, and hydrophilically-treated carbon black 46.

The hydrophilicity-treated particles used in the present invention have a methanol wettability of preferably 85% or less, more preferably 80% or less.
Methanol wettability indicates the concentration of methanol in which the total amount of hydrophilically treated particles is suspended in a solution in a wettability test with a methanol / water mixed solvent.

  When the content is within the above range, a carboxy group (—COOH) or an ester group (—COO—) present on the particle surface and a water molecule in the resin coating layer form a hydrogen bond. Adhesion with the coating layer is improved. When an acrylic resin is used in the resin coating layer, a π-π interaction occurs between a π bond in the acrylic resin and a carboxy group or an ester group present on the particle surface, and the filler and the resin coating layer The adhesion is improved. Further, due to the interaction between the particle surface functional groups and the hydroxy groups (-OH) on the surface of the magnetic core, the adhesion between the filler and the magnetic core is improved.

  As a result, even when used in a high-temperature and high-humidity environment for a long period of time, the resin coating layer does not suffer from scraping or peeling, and can maintain a stable charging ability. In other words, since the charging characteristics of the toner are stable for a long period of time, the variation in color mixture, the roughness (dot reproducibility), the developability, and the stability of gradation are improved. Further, carrier adhesion in a solid image, which is conspicuous when the charge of the magnetic carrier itself is small, tends to be hardly developed.

  In addition, since water molecules in the resin coating layer are retained, the moisture content of the magnetic carrier hardly changes even when the environment changes. Therefore, the amount of water, which greatly affects the charging characteristics of the carrier, is unlikely to change in response to a change from a high-temperature, high-humidity environment to a normal-temperature, low-humidity environment. As a result, whitening and gradation stability when the environment changes are improved.

The hydrophilically treated particles used in the present invention preferably have an ester group and / or a carboxyl group on the surface thereof, and preferably have a functional group concentration of the ester group and / or the carboxyl group of 20% or more. , 30% or more.
The functional group concentration indicates a ratio of an ester group or a carboxyl group to an element derived from particles in X-ray photoelectron spectroscopy (hereinafter also referred to as XPS) measurement.

  By being in the above range, a carboxy group or an ester group present on the particle surface and a water molecule in the resin coating layer form a hydrogen bond, and the interaction between the filler and the resin coating layer is improved by the interaction. . When an acrylic resin is used in the resin coating layer, a π-π interaction occurs between a π bond in the acrylic resin and a carboxy group or an ester group present on the particle surface, and the filler and the resin coating layer The adhesion is improved. Further, due to the interaction between the particle surface functional groups and the hydroxy groups on the surface of the magnetic core, the adhesion between the filler and the magnetic core is improved.

  As a result, even when used in a high-temperature and high-humidity environment for a long period of time, the resin coating layer does not suffer from scraping or peeling, and can maintain a stable charging ability. In other words, since the charging characteristics of the toner are stable for a long period of time, the variation in color mixture, the roughness (dot reproducibility), the developability, and the stability of gradation are improved. Further, carrier adhesion in a solid image, which is conspicuous when the charge of the magnetic carrier itself is small, tends to be hardly developed.

  In addition, since water molecules in the resin coating layer are retained, the moisture content of the magnetic carrier hardly changes even when the environment changes. Therefore, the amount of water, which greatly affects the charging characteristics of the carrier, is unlikely to change in response to a change from a high-temperature, high-humidity environment to a normal-temperature, low-humidity environment. As a result, whitening and gradation stability when the environment changes are improved.

It is preferable that the hydrophilically treated metal element oxide particles used in the present invention are one or two or more selected from TiO ₂ , AlO ₃ , MgO and SrTiO ₃ .
When particles other than those described above are used, the change in the water content of the carrier is increased due to the water adsorption ability of the particles themselves. For this reason, the amount of water greatly affecting the charging characteristics of the carrier changes with the change from the high-temperature and high-humidity environment to the normal-temperature and low-humidity environment, and the stability of the charging ability is reduced. As a result, whitening and gradation changes when the environment changes are reduced. In addition, since the carrier does not have an appropriate resistance range and cannot have a stable charge-imparting ability, fluctuations in color mixture, roughness (dot reproducibility), developability, gradation stability, and carrier adhesion are difficult. descend.

  It is not preferable to use organic fine particles in the present invention. When a thermosetting resin is used as the organic fine particles, it is considered that the resin molecular chains are randomly entangled and the functional group showing hydrophilicity is not oriented on the resin surface layer due to the production method. Therefore, the effects of the present invention such as durability due to the improvement in adhesion and environmental stability are not exhibited. When a thermoplastic resin is used, a part thereof may be dissolved in the resin solution, a uniform coat layer cannot be formed, and the effects of the present invention cannot be obtained.

The volume average diameter of the primary particles of the hydrophilically treated particles used in the present invention is preferably 10 nm or more and 1000 nm or less.
When the volume average diameter of the primary particles of the hydrophilically treated particles is 10 nm or more, the particles are less likely to aggregate. For this reason, it is difficult for the charge imparting ability to decrease due to the detachment of the aggregate from the filler. That is, since the charging characteristics of the toner can be maintained for a long period of time, a change in tint of mixed colors, roughness (dot reproducibility), developability, and a change in gradation hardly occur. Further, carrier adhesion in a solid image, which is conspicuous when the charge of the magnetic carrier itself is small, hardly occurs. In addition, when the environment changes, the moisture content of the magnetic carrier hardly greatly changes due to the detachment of the aggregate. For this reason, the change in the amount of water, which greatly affects the charging characteristics of the carrier, is reduced with respect to the change from the high-temperature and high-humidity environment to the normal-temperature and low-humidity environment. As a result, white spots and gradation changes when the environment changes are less likely to occur.

  When the volume average diameter of the primary particles of the hydrophilically treated particles is 1000 nm or less, the particles are less likely to be detached from the resin coating layer, and the charge-imparting ability is not easily reduced. That is, since the charging characteristics of the toner can be maintained for a long period of time, a change in tint of mixed colors, roughness (dot reproducibility), developability, and a change in gradation hardly occur. Further, carrier adhesion in a solid image, which is conspicuous when the charge of the magnetic carrier itself is small, hardly occurs. In addition, when the environment changes, the moisture content of the magnetic carrier hardly greatly changes due to the detachment of the aggregates. Therefore, even when the environment changes from a high-temperature and high-humidity environment to a normal-temperature and low-humidity environment, a change in the amount of water, which greatly affects the charging characteristics of the carrier, does not increase so that a stable charging ability can be maintained. As a result, white spots and gradation changes when the environment changes are less likely to occur.

The filler used in the present invention preferably contains the hydrophilically-treated particles in an amount of 1.0 to 20.0 parts by mass when the resin is 100 parts by mass.
When the content of the particles subjected to the hydrophilic treatment is 1.0 part by mass or more, the absolute amount of the surface functional groups that interact with the water molecules in the resin coating layer is sufficient, and the adhesion between the filler and the resin coating layer is sufficient. Sex is improved. As a result, when used in a high-temperature, high-humidity environment for a long period of time, the resin coating layer is less likely to be scraped or peeled off, and a stable charge-imparting ability can be maintained. That is, since the charging characteristics of the toner can be maintained for a long period of time, a change in tint of mixed colors, roughness (dot reproducibility), developability, and a change in gradation hardly occur. Further, carrier adhesion in a solid image, which is conspicuous when the charge of the magnetic carrier itself is small, hardly occurs. In addition, since the water molecules in the resin coating layer are maintained, the change in the water content in the resin does not increase even when the environment changes. As a result, the change in the amount of water that greatly affects the charging characteristics of the carrier with respect to the change from the high-temperature and high-humidity environment to the normal-temperature and low-humidity environment is reduced. . As a result, white spots and gradation changes when the environment changes are less likely to occur.

On the other hand, when the content of the particles subjected to the hydrophilic treatment is 20.0 parts by mass or less, the absolute amount of the particle surface functional groups interacting with the water molecules in the resin coating layer does not become too large, and the water molecules are filled. It is unlikely to be overly attracted in the direction. As a result, water molecules near the surface layer of the surface resin are not reduced, and the water content of the entire resin is not increased by adsorbing water molecules in the air. As a result, even when used in a high-temperature and high-humidity environment for a long period of time, the resin coating layer is not scraped or peeled off, and stable charging ability cannot be maintained.
That is, since the charging characteristics of the toner can be maintained for a long period of time, a change in tint of mixed colors, roughness (dot reproducibility), developability, and a change in gradation hardly occur. Further, carrier adhesion in a solid image, which is conspicuous when the charge of the magnetic carrier itself is small, hardly occurs. In addition, when the environment changes due to an increase in the water content of the resin coating layer, the change in the water content of the magnetic carrier hardly increases.
As a result, the change in the amount of water, which greatly affects the charging characteristics of the carrier, does not increase significantly from the high-temperature, high-humidity environment to the normal temperature, low-humidity environment. Can be. As a result, white spots and gradation changes when the environment changes are less likely to occur.

The thickness of the resin coating layer used in the present invention is preferably 0.01 μm or more and 4.00 μm or less.
When there is no region of less than 0.01 μm in the thickness of the resin coating layer, it is hardly affected by the particles subjected to the hydrophilic treatment, and the change in the water content of the magnetic carrier hardly increases when the environment changes. As a result, the change in the amount of water that greatly affects the charging characteristics of the carrier with respect to the change from the high-temperature and high-humidity environment to the normal-temperature and low-humidity environment is reduced. . As a result, white spots and gradation changes when the environment changes are less likely to occur.

  On the other hand, when there is no region exceeding 4.0 μm in the film thickness of the resin coating layer, the resin coating layer is less susceptible to moisture desorption and the change in the moisture content of the magnetic carrier during environmental changes is unlikely to increase. As a result, the change in the amount of water that greatly affects the charging characteristics of the carrier with respect to the change from the high-temperature and high-humidity environment to the normal-temperature and low-humidity environment is reduced. . As a result, white spots and gradation changes when the environment changes are less likely to occur.

The magnetic carrier of the present invention,
The moisture content of the magnetic carrier when left standing for 24 hours in an environment of a temperature of 30 ° C. and a humidity of 80% is A mass%,
When the magnetic carrier was left standing for 24 hours in an environment of a temperature of 23 ° C. and a humidity of 5% after standing for 24 hours in an environment of a temperature of 30 ° C. and a humidity of 80%, and the moisture content of the magnetic carrier was B mass%.
It is preferable that the change in water content (AB) be 0.03% by mass or less.
When the change in the moisture content is 0.03% by mass or less, the change in the amount of water that greatly affects the charging characteristics of the carrier is small with respect to the change from the high-temperature and high-humidity environment to the normal temperature and low-humidity environment. As a result, stable charging ability can be maintained. As a result, white spots and gradation changes when the environment changes are less likely to occur.
Next, the method for hydrophilically treating particles of the present invention will be described.

<Method for hydrophilic treatment of particles>
The metal element oxide particles, silica particles, and carbon black contained in the filler of the present invention require that the particle surfaces be subjected to hydrophilic treatment.
As one of the hydrophilic treatment methods, for example, a neutral or basic carbon black or an acidic carbon black can be subjected to an oxidation treatment to introduce a hydrophilic group.

  As a specific example of the oxidation treatment method, in the oxidation method by air contact, there is a gas phase oxidation method by reaction with nitrogen oxide or ozone. In addition, a liquid phase oxidation method using an oxidizing agent such as nitric acid, potassium permanganate, potassium dichromate, dumbric acid, perchloric acid, hypohalous hydrochloric acid, hydrogen peroxide, an aqueous bromine solution, and an aqueous ozone solution may be used. . In addition, the present invention can be similarly applied to carbon black whose surface is oxidized by plasma treatment or the like.

  There are various methods for introducing a hydrophilic group by oxidizing the particle surface as described above. For example, the following method is preferable. In the case of performing liquid phase oxidation, carbon black is placed in a suitable container, an aqueous solution of nitric acid is added thereto, and the mixture is refluxed, followed by washing and drying to obtain hydrophilically treated particles. When performing the gas phase oxidation method, it is possible to obtain hydrophilically treated particles by putting each particle into a cylindrical ozonizer, generating ozone with an ozone generator, and exposing the particles to an ozone atmosphere. it can.

Further, as one of the hydrophilic treatment methods, for example, by performing a hydrophilic esterification agent or carboxylation treatment of a lower fatty acid, a hydrophilic ester group or a carboxyl group of a lower fatty acid is introduced into a hydroxy group on the particle surface. Method.
Specific examples of the hydrophilic esterifying agent include acetic anhydride, acetic chloride, acetic acid, propionic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, polyglycerin fatty acid ester, and alginic acid. These hydrophilic esterifying agents or carboxylating agents for lower fatty acids may be used as a mixture of two or more.

As a hydrophilic treatment method as described above, a method of introducing a hydrophilic ester group or a carboxyl group of a lower fatty acid into a hydroxy group on the particle surface by performing a hydrophilic esterifying agent or a carboxylation treatment of a lower fatty acid. Exists. For example, it is preferable to take the following method. Each particle type is put in an appropriate container, the system is placed under a nitrogen atmosphere, and then anhydrous toluene, triethylamine, dimethylaminopyridine, and acetic anhydride are added and reacted at room temperature to obtain chemically modified particles. Thereafter, the obtained chemically modified particles are placed in an appropriate container, methanol and calcium carbonate are added, and the mixture is allowed to react at room temperature. Thereafter, the reaction is stopped, and the particles subjected to the hydrophilic treatment are washed and dried. Obtainable.
Next, a method for producing the porous magnetic core particles of the present invention will be described.

<Method for producing porous magnetic core particles>
The porous magnetic core particles of the present invention can be produced by the following steps.
As the material of the porous magnetic core particles, magnetite or ferrite is preferable. Further, the material of the porous magnetic core particles is more preferably ferrite because the porous structure of the porous magnetic core particles can be controlled and the electric resistance can be adjusted.

Ferrite is a sintered body represented by the following general formula.
(M1 ₂ O) _x (M2O) _y (Fe ₂ O ₃ ) _z
(Where M1 is a monovalent metal, M2 is a divalent metal, and when x + y + z = 1.0, x and y are respectively 0 ≦ (x, y) ≦ 0.8, and z is 0.2 <z <1.0.)
In the formula, it is preferable to use one or more metal atoms selected from the group consisting of Li, Fe, Mn, Mg, Sr, Cu, Zn, and Ca as M1 and M2.

In a magnetic carrier, it is required to maintain an appropriate amount of magnetization, to keep the pore size in a desired range, and to make the surface of the porous magnetic core particles uneven. It is also required that the rate of the ferrite-forming reaction can be easily controlled, and the specific resistance and magnetic force of the porous magnetic core can be suitably controlled. From the above viewpoints, Mn-based ferrite, Mn-Mg-based ferrite, Mn-Mg-Sr-based ferrite, and Li-Mn-based ferrite containing Mn elements are more preferable. Among them, Mn-Mg-Sr-based ferrite is most preferable from the relationship between specific resistance and magnetic force.
Hereinafter, the production process when ferrite is used as the porous magnetic core particles will be described in detail.

・ Step 1 (weighing / mixing step):
The ferrite raw materials are weighed and mixed. Examples of the ferrite raw material include the following. Metal particles, oxides, hydroxides, carbonates, oxalates of Li, Fe, Mn, Mg, Sr, Cu, Zn, Ca. Examples of the mixing device include the following. The use of hydroxides or carbonates as the raw material species to be blended tends to increase the pore volume as compared with the case where oxides are used. Ball mill, planetary mill, geot mill, vibration mill. Particularly, a ball mill is preferable from the viewpoint of mixing properties.
Specifically, a weighed ferrite raw material and a ball are put into a ball mill, and are crushed and mixed for 0.1 to 20.0 hours.

Step 2 (temporary firing step):
After the pulverized and mixed ferrite raw material is formed into a pellet using a pressure molding machine or the like, a preliminary firing is performed. As described above, since the preliminary firing step is important for obtaining the magnetic carrier of the present invention, it is important to perform it under the above-described conditions. For example, at a firing temperature of 1000 ° C. or more and 1100 ° C. or less, pre-firing is performed for 3 hours or more and 5.0 hours or less to obtain ferrite as a material. At this time, the mixing amount is appropriately adjusted so that the ferrite-forming reaction proceeds sufficiently. In addition, it is preferable to adjust the atmosphere, in particular, to lower the oxygen concentration such as under a nitrogen atmosphere, so that the ferrite-forming reaction proceeds more easily. For firing, for example, the following furnace is used. A burner type firing furnace, a rotary type firing furnace, an electric furnace, and the like can be given.

・ Step 3 (crushing step):
The calcined ferrite produced in step 2 is pulverized by a pulverizer. The pulverizer is not particularly limited as long as a desired particle size is obtained. For example, the following are mentioned. Crusher, hammer mill, ball mill, bead mill, planetary mill, geot mill. However, since the calcined product of the present case is a calcined product in which a part of the conventional calcined product has undergone a ferrite-forming reaction, the hardness is high. Therefore, in order to obtain a desired particle size, it is necessary to increase the crushing strength. It is important to increase the crushing strength and to control the particle size and the particle size distribution of the finely pulverized calcined ferrite in order to control the grain size to be small and uniform.
In addition, controlling the particle size and the particle size distribution of the finely pulverized product has a correlation with the average pore size of the porous magnetic core particles and the degree of unevenness of the surface of the magnetic carrier, and is useful for controlling the resin abundance of the magnetic carrier. Also leads.

In order to control the particle size distribution of the finely pulverized calcined ferrite, for example, it is preferable to control the material of balls and beads used in a ball mill or bead mill and the operation time. Specifically, in order to reduce the particle size of the calcined ferrite, a ball having a high specific gravity may be used, or the grinding time may be lengthened. The material of the balls and beads is not particularly limited as long as a desired particle size and distribution can be obtained. For example, the following are mentioned. Glass such as soda glass (specific gravity 2.5 g / cm ³ ), soda-less glass (specific gravity 2.6 g / cm ³ ), high specific gravity glass (specific gravity 2.7 g / cm ³ ), and quartz (specific gravity 2.2 g / cm ³ ) ³ ), titania (specific gravity 3.9 g / cm ³ ), silicon nitride (specific gravity 3.2 g / cm ³ ), alumina (specific gravity 3.6 g / cm ³ ), zirconia (specific gravity 6.0 g / cm ³ ), steel ( Specific gravity 7.9 g / cm ³ ), stainless steel (specific gravity 8.0 g / cm ³ ). Among them, alumina, zirconia, and stainless steel are preferable because of their excellent wear resistance. The particle size of the balls and beads is not particularly limited as long as a desired particle size and distribution can be obtained. For example, a ball having a diameter of 4 mm or more and 60 mm or less is suitably used. Beads having a diameter of 0.03 mm or more and 5 mm or less are preferably used. In the ball mill and the bead mill, the wet type is higher in the pulverization efficiency than the dry type because the pulverized product does not flutter in the mill. For this reason, the wet type is more preferable than the dry type.

Step 4 (granulation step):
A dispersing agent, water, a binder and, if necessary, a pore adjuster may be added to the finely pulverized calcined ferrite. Examples of the pore adjusting agent include a foaming agent and resin fine particles. As the binder, for example, polyvinyl alcohol is used. In step 3, when pulverization is performed by a wet method, it is preferable to add a binder and, if necessary, a pore-conditioning agent in consideration of water contained in the ferrite slurry.
The obtained ferrite slurry is dried and granulated using a spray dryer under a heating atmosphere at a temperature of 100 ° C. or more and 200 ° C. or less. The spray dryer is not particularly limited as long as a desired particle size is obtained. For example, a spray dryer can be used.
Next, the dispersant and binder are removed from the granulated product by burning at a temperature of 600 ° C. or more and 800 ° C. or less.

Step 5 (final firing step):
Thereafter, firing is performed at a temperature of 1000 ° C. or more and 1300 ° C. or less for 1 hour or more and 24 hours or less in an electric furnace in which the oxygen concentration can be controlled in an atmosphere where the oxygen concentration is controlled. By controlling the temperature, the pore volume can be controlled. For example, by increasing the temperature, the pore volume decreases. Incidentally, the pore volume of the porous magnetic core particles may preferably 20.0 mm ³ / g or more 100.0 mm ³ / g or less.

  In the calcination step, although the ferrite-forming reaction has sufficiently proceeded, the time of the temperature rise and fall through the range of 700 ° C. to 1100 ° C., which is the temperature range in which the ferrite-forming reaction proceeds, is shortened. Control so that the ferrite-forming reaction does not progress. On the other hand, the holding time of the top temperature is preferably set to 3 hours or more and 5 hours or less. At that time, a rotary electric furnace, a batch electric furnace, or a continuous electric furnace is used.The firing atmosphere is also controlled by driving an inert gas such as nitrogen or a reducing gas such as hydrogen or carbon monoxide into Density control may be performed. In the case of a rotary electric furnace, firing may be performed many times by changing the atmosphere and the firing temperature.

Step 6 (sorting step):
After disintegrating the fired particles, if necessary, low magnetic products are separated by magnetic separation. Coarse particles and fine particles may be removed by air classification or sieving with a sieve.
・ Surface treatment process:
If necessary, the surface can be heated at a low temperature to perform an oxide film treatment to adjust the resistance. For the oxide film treatment, a general rotary electric furnace, batch electric furnace, or the like can be used, and heat treatment can be performed at, for example, 300 ° C. or more and 700 ° C. or less.

The 50% particle size (D50) based on the volume distribution of the porous magnetic core particles obtained as described above is 28.30 to 80.0 μm in order to make the final magnetic carrier particle size 30.0 μm or more and 80.0 μm or less. It is preferably from 0 μm to 78.0 μm. As a result, the ability to impart frictional charge to the toner is improved, the image quality of the halftone portion is satisfied, and fog and carrier adhesion can be suppressed.
The specific resistance of the porous magnetic core is 1.0 × 10 ⁷ Ω · cm or more and 1.0 × 10 ⁸ Ω · cm or less at an electric field strength of 300 (V / cm). This is preferable because it can be increased.
Next, a method for producing the filled core particles will be described.

(Method for producing filled core particles)
As a method for filling the voids of the porous magnetic core with the filler, a method of diluting the filler resin and the additive with a solvent, adding the diluted resin to the voids of the porous magnetic core, and removing the solvent can be adopted. The solvent used here may be any solvent that can dissolve the filling resin. Examples of the organic solvent include toluene, xylene, cellosolve butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and methanol. As a method of filling the filler into the voids of the porous magnetic core, the porous magnetic core is impregnated with the filler solution by a coating method such as a dipping method, a spray method, a brush coating method, and a fluidized bed, and then, the solvent Is volatilized.
As the immersion method, it is preferable to fill the pores of the porous magnetic core particles with a filler solution obtained by mixing a filler resin, an additive and a solvent under reduced pressure, and remove the solvent by degassing or heating.

In the present invention, it is preferable to control the solvent removal speed by the deaeration time to control the impregnation of the porous magnetic core particles with the filler into the pores. Since the filled filler impregnates the inside of the voids by the capillary phenomenon, the longer the time, the more the resin is impregnated inside the porous magnetic core.
After filling the filler, it is heated by various methods as necessary, and the filled filler is brought into close contact with the porous magnetic core particles. The heating method may be either an external heating method or an internal heating method, for example, a fixed or fluid electric furnace, a rotary electric furnace, a burner furnace, or baking by microwave.

The amount of the filling resin to be filled is preferably 2.0% by mass or more and 8.0% by mass with respect to the porous magnetic core particles, so that the total amount of the resin can be easily adjusted and the coatability of the resin coating layer composition. It is preferable from the viewpoint of the improvement of.
The filling resin solid content in the filler is preferably 6% by mass or more and 25% by mass or less, from the viewpoint of the filling property up to the pores and the time for removing the solvent, since the handling of the viscosity of the filler solution is good.

  The filler resin in the filler filling the voids of the porous magnetic core is not particularly limited, but a resin having high impregnation properties is preferable. When a resin having a high impregnation property is used, pores near the surface of the filled core particles remain by filling from the pores inside the porous magnetic core particles, and the surface of the filled core particles has irregularities due to the pores. Since it has a shape, it is preferable from the viewpoint of the surface tension of the resin coating layer composition as described above.

  The filler resin in the filler may be either a thermoplastic resin or a thermosetting resin, and is a polymer obtained by polymerizing a monomer containing a (meth) acrylate monomer, or a silicone resin. When the above-mentioned filling resin is used, problems such as chipping and peeling occur even after long-term use due to the excellent adhesion to the magnetic core and the resin coating layer, and the excellent strength and toughness of the filling resin itself. It is preferable because it is difficult to perform.

  Those usable as (meth) acrylate monomers include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, normal butyl acrylate, isobutyl acrylate, tert-butyl acrylate, acrylic acid 2 -Ethylhexyl, lauryl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecyl acrylate, octadecyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate N-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, methacrylic acid Dodecyl, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate acid and methacrylic acid heptadecyl and octadecyl methacrylate.

  Examples of straight silicone resins include KR-271, KR-251 and KR-255 manufactured by Shin-Etsu Chemical Co., Ltd., SR2400, SR2405, SR2410 (methyl silicone) and SR2411 manufactured by Dow Corning Toray Co., Ltd. Examples of the modified silicone resin include KR206 (alkyd-modified), KR5208 (acryl-modified), ES1001N (epoxy-modified), and SR2110 (alkyd-modified) manufactured by Shin-Etsu Chemical Co., Ltd.

  When a silicone resin is used as the filling resin, it is preferable that a silane coupling agent is contained as an additive. The silane coupling agent has good compatibility with the filling resin, and the wettability and adhesion between the porous magnetic core particles and the filling resin are further improved. Therefore, the filling resin is filled from the pores inside the porous magnetic core particles. As a result, the surface of the filled core particles has a shape with irregularities due to pores, and thus is preferable from the viewpoint of the surface tension of the resin coating layer composition as described above.

The silane coupling agent to be used is not particularly limited, but an aminosilane coupling agent is preferable because the presence of a functional group also improves the affinity with the resin coating layer composition.
The reason why the aminosilane coupling agent enhances the wettability and adhesion between the porous magnetic core particles and the filler resin and improves the affinity with the resin coating layer composition is considered as follows. The aminosilane coupling agent has a part that reacts with an inorganic substance and a part that reacts with an organic substance. In general, an alkoxy group (—OR. R represents an alkyl group) contains an inorganic substance and an amino group (− It is considered that the functional group having NH ₂ ) reacts with an organic substance. Therefore, the alkoxy group of the aminosilane coupling agent reacts with the portion of the porous magnetic core particles, thereby increasing wettability and adhesion, and the functional group having an amino group is oriented toward the filling resin side, whereby the resin It is considered that the affinity with the coating layer composition is also increased.
The amount of the silane coupling agent to be added is preferably 1.0 to 20.0 parts by mass based on 100 parts by mass of the charged resin. More preferably, it is 5.0 to 10.0 parts by mass from the viewpoint of improving the wettability and adhesion between the porous magnetic core particles and the filling resin.
Next, a method for manufacturing a magnetic carrier will be described.

<Method for producing magnetic carrier>
A method for coating the surface of the filled core particles with the resin coating layer composition is not particularly limited, and examples thereof include a method of applying a coating method such as a dipping method, a spray method, a brush coating method, a dry method, and a fluidized bed. .
The same method as in the filling step is used for adjusting the resin coating layer composition solution to be coated. Methods for suppressing granulation during the coating step include adjusting the resin concentration in the resin coating layer composition solution, the temperature in the coating apparatus, the temperature and degree of decompression when removing the solvent, the number of times of the resin coating step, and the like. No.
The coating resin in the resin coating layer is a polymer obtained by polymerizing a monomer containing a (meth) acrylate monomer. When the above-mentioned coating resin is used, problems such as scraping and peeling occur even after long-term use due to the excellent adhesion to the magnetic core and the filler, and the excellent strength and toughness of the coating resin itself. It is preferable because it is difficult.

  Those usable as (meth) acrylate monomers include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, normal butyl acrylate, isobutyl acrylate, tert-butyl acrylate, acrylic acid 2 -Ethylhexyl, lauryl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecyl acrylate, octadecyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate N-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, methacrylic acid Dodecyl, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate acid and methacrylic acid heptadecyl and octadecyl methacrylate.

It is preferable that the resin used for the coating layer is a graft polymer because the wettability with the porous magnetic core particles is further improved and a uniform coating layer is formed.
In order to obtain a graft polymer, there are a method of graft polymerization after forming a main chain, and a method of copolymerizing using a macromonomer as a monomer. It is preferable because it can be easily controlled.
The macromonomer to be used is not particularly limited, but a methyl methacrylate macromonomer is preferable because the wettability with the porous magnetic core is further improved.
The amount used when polymerizing the macromonomer is preferably from 10 to 50 parts by mass, more preferably from 20 to 40 parts by mass, based on 100 parts by mass of the main chain copolymer of the vinyl resin.

  Further, the resin coating layer composition may contain particles having conductivity and particles or materials having charge controllability. Examples of the conductive particles include carbon black, magnetite, graphite, zinc oxide, and tin oxide. Among them, by suitably acting the filler effect of carbon black, the surface tension of the resin coating layer composition can be suitably exerted, which is preferable from the viewpoint of improving the coatability of the resin coating layer composition.

  The reason why the filler effect of the carbon black can be suitably applied to improve the coatability of the resin coating layer composition is based on the primary particle diameter and the cohesiveness of the carbon black. That is, since carbon black has a small primary particle diameter, it shows a large specific surface area. On the other hand, since carbon black has high cohesion, it exists as large particles as aggregated particles. Due to the primary particle size and the cohesiveness, the particles can greatly deviate from the relationship between the particle size and the specific surface area. That is, since the particle diameter is such that the surface tension of the resin coating layer composition acts and the contact point is large due to the specific surface area, the surface tension of the resin coating layer composition easily acts.

The amount of the conductive particles to be added is preferably from 0.1 to 10.0 parts by mass based on 100 parts by mass of the resin coating layer in order to adjust the electric resistance of the magnetic carrier. The particles having charge controllability include the following.
Organometallic complex particles, organometallic salt particles, chelate compound particles, monoazo metal complex particles, acetylacetone metal complex particles, hydroxycarboxylic acid metal complex particles, polycarboxylic acid metal complex particles, polyol metal complex particles , Polymethyl methacrylate resin particles, polystyrene resin particles, melamine resin particles, phenol resin particles, nylon resin particles, silica particles, titanium oxide particles, and alumina particles.
The addition amount of the 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 resin coating layer in order to adjust the triboelectric charge amount.
Next, the configuration of a toner that is preferable for achieving the object in the present invention will be described.

<Configuration of Toner>
Examples of the binder resin used in the present invention include a vinyl resin, a polyester resin, and an epoxy resin. Among them, vinyl resins and polyester resins are more preferable in terms of chargeability and fixability.
In the present invention, the following polymers and resins can be used by mixing them with the above-mentioned binder resin as required.
Homopolymer or copolymer of vinyl monomer, polyester resin, polyurethane resin, epoxy resin, polyvinyl butyral resin, rosin resin, modified rosin resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic Petroleum resin.

When two or more resins are mixed and used as a binder resin, as a more preferred form, those having different molecular weights are preferably mixed at an appropriate ratio.
The glass transition temperature of the binder resin is preferably 45 to 80 ° C, more preferably 55 to 70 ° C, the number average molecular weight (Mn) is 2,500 to 50,000, and the weight average molecular weight (Mw) is 10,000. Preferably it is ~ 1,000,000.

As the binder resin, the following polyester resins are also preferable.
In the polyester resin, 45 to 55 mol% of all components are alcohol components, and 55 to 45 mol% are acid components.
The acid value of the polyester resin is preferably 90 mgKOH / g or less, more preferably 50 mgKOH / g or less, and the OH value is preferably 50 mgKOH / g or less, more preferably 30 mgKOH / g or less. This is because the environmental dependence of the charging characteristics of the toner increases as the number of terminal groups in the molecular chain increases.
The glass transition temperature of the polyester resin is preferably from 50 to 75 ° C, more preferably from 55 to 65 ° C. The number average molecular weight (Mn) is preferably from 1,500 to 50,000, more preferably from 2,000 to 20,000. The weight average molecular weight (Mw) is preferably from 6,000 to 100,000, more preferably from 10,000 to 90,000.

When the toner of the present invention is used as a magnetic toner, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, maghemite, and ferrite, and iron oxides containing other metal oxides; such as Fe, Co, and Ni. Metals or alloys of these metals with metals such as Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, V And mixtures thereof.
Specifically, as the magnetic material, ferric oxide (Fe ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc oxide (ZnFe ₂ O ₄ ), yttrium iron oxide (Y ₃ Fe ₄ ) ₅ O ₁₂ ), iron cadmium oxide (CdFe ₂ O ₄ ), iron gadolinium oxide (Gd ₃ Fe ₅ O ₁₂ ), iron oxide copper (CuFe ₂ O ₄ ), lead iron oxide (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂ O ₄ ), iron neodymium oxide (NdFe ₂ O ₃ ), barium iron oxide (BaFe ₁₂ O ₁₉ ), magnesium iron oxide (MgFe ₂ O ₄ ), iron manganese oxide (MnFe ₂ O ₄ ), lanthanum iron oxide (LaFeO ₃ ), iron powder (Fe), cobalt powder (Co), nickel powder (Ni) and the like.
These are used in an amount of 20 to 150 parts by mass, preferably 50 to 130 parts by mass, and more preferably 60 to 120 parts by mass, based on 100 parts by mass of the binder resin.
The non-magnetic coloring agent used in the present invention includes the following.

Examples of the black colorant include those adjusted to black using carbon black; a yellow colorant, a magenta colorant, and a cyan colorant.
Examples of the coloring pigment for magenta toner include the following. Examples include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. 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; I. Pigment Violet 19, C.I. I. Butt Red 1, 2, 10, 13, 15, 23, 29, 35.

As the colorant, a pigment alone may be used, but it is preferable to improve the sharpness by using a dye and a pigment in combination from the viewpoint of the image quality of a full-color image.
The dyes for magenta toner include the following. C. I Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, C.I. I. Disperse Red 9, C.I. I. Solvent Violet 8, 13, 14, 21, 27, C.I. I. Oil-soluble dyes such as Disper Violet 1, 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 dyes such as Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

Examples of the coloring pigment for cyan toner include the following. C. I. Pigment Blue 1, 2, 3, 7, 15: 2, 15: 3, 15: 4, 16, 17, 60, 62, 66; I. Bat Blue 6, C.I. I. Acid Blue 45, a copper phthalocyanine pigment obtained by substituting 1 to 5 phthalimidomethyl in the phthalocyanine skeleton.
The following are mentioned as coloring pigments for yellow. Condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal compounds, methine compounds, 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, C. 109, 110, 111, 120, 127, 128, 129, 147, 155, 168, 174, 180, 181, 185, 191; I. Bat Yellow 1, 3, and 20. C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6 and Solvent Yellow 162 can also be used.

The amount of the colorant to be used is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and most preferably 3 to 15 parts by mass with respect to 100 parts by mass of the binder resin. is there.
Further, in the toner, it is preferable to use a toner prepared by mixing a binder with a coloring agent in advance and forming a master batch. By melting and kneading the colorant masterbatch and other raw materials (binder resin, wax, and the like), the colorant can be favorably dispersed in the toner.

In the toner of the present invention, a charge control agent can be used as needed in order to further stabilize the chargeability. It is preferable to use 0.5 to 10 parts by mass of the charge control agent per 100 parts by mass of the binder resin. When the amount is less than 0.5 part by mass, sufficient charging characteristics may not be obtained in some cases, and when the amount is more than 10 parts by mass, compatibility with other materials is reduced, or charging is performed under low humidity. It may be excessive, which is not preferable.
Examples of the charge control agent include the following.

  For example, an organometallic complex or a chelate compound is effective as a negative charge controlling agent for controlling the toner to negative charge. Examples thereof include a monoazo metal complex, a metal complex of an aromatic hydroxycarboxylic acid, and a metal complex of an aromatic dicarboxylic acid. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides or esters thereof, and phenol derivatives of bisphenol.

  Examples of the positive charge controlling agent for controlling the toner to be positively charged include denaturation products such as nigrosine and fatty acid metal salts, and tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. Onium salts such as quaternary ammonium salts and phosphonium salts which are analogs thereof, and triphenylmethane dyes and these lake pigments as chelating pigments thereof (phosphorotungstic acid, phosphomolybdic acid, phosphorous tungsten Molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanide compounds, etc., and metal salts of higher fatty acids such as diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; Suzuboreto, dioctyl tin borate include diorgano tin borate such as dicyclohexyl tin borate.

In the present invention, if necessary, one or more release agents may be contained in the toner particles. The following are examples of the release agent.
Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax and paraffin wax can be preferably used. An oxide of an aliphatic hydrocarbon wax such as an oxidized polyethylene wax or a block copolymer thereof; waxes mainly containing a fatty acid ester such as carnauba wax, sasol wax and montanic acid ester wax; Fatty acid esters such as deoxidized carnauba wax are partially or entirely deoxidized.

The amount of the release agent is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin.
Further, the melting point of the release agent defined by the maximum endothermic peak temperature at the time of temperature rise measured by a differential scanning calorimeter (DSC) is preferably 65 to 130 ° C. The temperature is more preferably 80 to 125 ° C. When the melting point is lower than 65 ° C., the viscosity of the toner is reduced, and the toner tends to adhere to the photoreceptor. When the melting point is higher than 130 ° C., the low-temperature fixability may decrease, which is not preferable. .

In the toner of the present invention, a fine powder which can be added to the toner particles to increase the fluidity before and after the addition may be used as the fluidity improver. For example, fluorinated resin powder such as vinylidene fluoride fine powder and polytetrafluoroethylene (PTFE) fine powder; fine powder silica such as wet-process silica and dry process silica; fine-powder titanium oxide; It is preferable to apply a surface treatment with an agent, a titanium coupling agent, or a silicone oil and then perform a hydrophobic treatment.
The inorganic fine particles in the present invention are used in an amount of 0.1 to 10 parts by mass, preferably 0.2 to 8 parts by mass, based on 100 parts by mass of the toner.

When the toner of the present invention is used as a two-component developer by mixing it with a magnetic carrier, the carrier mixture ratio at that time is 2% by mass or more and 15% by mass or less, preferably 4% by mass, as the toner concentration in the developer. % To 13% by mass or less, good results are usually obtained. If the toner concentration is less than 2% by mass, the image density tends to be reduced, and if it exceeds 15% by mass, fogging and scattering in the machine tend to occur.
In addition, in a replenishing developer for replenishing the developing device in accordance with a decrease in the toner concentration of the two-component developer in the developing device, 2 parts by mass or more and 50 parts by mass of toner are added to 1 part by mass of the replenishing magnetic carrier. It contains below.
Next, an image forming apparatus including a developing device using the magnetic carrier, the two-component developer, and the replenishing developer of the present invention will be described with reference to an example. It is not limited to.
Next, an image forming method used in the present invention will be described.

<Image forming method>
In FIG. 1, the electrostatic latent image carrier 1 rotates in the direction of the arrow in the figure. The electrostatic latent image carrier 1 is charged by a charger 2 serving as a charging unit, and the surface of the charged electrostatic latent image carrier 1 is exposed by an exposure unit 3 serving as an electrostatic latent image forming unit. An electrostatic latent image is formed. The developing device 4 has a developing container 5 for storing a two-component developer, a developer carrier 6 is disposed in a rotatable state, and a magnet 7 is provided inside the developer carrier 6 as a magnetic field generating means. Is included. At least one of the magnets 7 is installed at a position facing the latent image carrier. The two-component developer is held on the developer carrier 6 by a magnetic field generated by the magnet 7, the amount of the two-component developer is regulated by the regulating member 8, and the two-component developer faces the electrostatic latent image carrier 1. To the developing section. In the developing section, a magnetic brush is formed by a magnetic field generated by the magnet 7. Thereafter, the electrostatic latent image is visualized as a toner image by applying a developing bias obtained by superposing an alternating electric field on the DC electric field. The toner image formed on the electrostatic latent image carrier 1 is electrostatically transferred to a recording medium 12 by a transfer charger 11.

  Here, as shown in FIG. 2, the image may be once transferred from the electrostatic latent image carrier 1 to the intermediate transfer body 9 and then electrostatically transferred to the transfer material (recording medium) 12.

After the transfer of the toner image, the recording medium 12 is conveyed to a fixing device 13 where the toner is fixed on the recording medium 12 by being heated and pressed. Thereafter, the recording medium 12 is discharged out of the apparatus as an output image.
After the transfer step, the toner remaining on the electrostatic latent image carrier 1 is removed by the cleaner 15. Thereafter, the electrostatic latent image carrier 1 cleaned by the cleaner 15 is electrically initialized by light irradiation from the pre-exposure 16, and the above-described image forming operation 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.
The arrangement (relative positional relationship) of each image forming unit such as K, Y, C, and M in the figure and the rotation direction indicated by the arrow are not limited to these. Incidentally, K means black, Y means yellow, C means cyan, and M means magenta. In FIG. 2, the electrostatic latent image carriers 1K, 1Y, 1C, and 1M rotate in the direction of the arrow in the figure. Each electrostatic latent image carrier is charged by chargers 2K, 2Y, 2C, and 2M as charging means. The surface of each charged electrostatic latent image carrier is exposed by exposure units 3K, 3Y, 3C, and 3M, which are electrostatic latent image forming means, and an electrostatic latent image is formed. Thereafter, the electrostatic latent image is converted into a toner image by the two-component developer carried on the developer carrying members 6K, 6Y, 6C and 6M provided in the developing devices 4K, 4Y, 4C and 4M as developing means. Visualized. Further, the image is transferred to the intermediate transfer member 9 by the intermediate transfer chargers 10K, 10Y, 10C, and 10M as transfer means.

  The toner image transferred to the intermediate transfer member 9 is transferred to a recording medium 12 by a transfer charger 11 as a transfer unit. The toner image transferred to the recording medium 12 is fixed under heat and pressure by a fixing device 13 serving as a fixing unit, and is output as an image. Then, the intermediate transfer member cleaner 14, which is a cleaning member of the intermediate transfer member 9, collects the transfer residual toner and the like.

  Specifically, as the developing method of the present invention, an AC voltage is applied to the developer carrier to form an alternating electric field in the developing area, and the developing is performed in a state where the magnetic brush is in contact with the photoconductor. Is preferred. The distance (S-D distance) between the developer carrier (developing sleeve) and the electrostatic latent image carrier (photosensitive drum) should be 100 μm or more and 1000 μm or less, in order to suppress carrier adhesion and improve dot reproducibility. Good. When the distance between SD is 100 μm or more, the developer is sufficiently supplied, and an appropriate image density can be obtained. If the distance between SD is 1000 μm or less, the lines of magnetic force from the magnetic pole S1 are widened, the density of the magnetic brush is reduced, the dot reproducibility is poor, the force for restraining the magnetic coated carrier is weakened, and carrier adhesion is likely to occur. It doesn't even fall.

  The voltage (Vpp) between the peaks of the alternating electric field is 300 V or more and 3000 V or less, preferably 500 V or more and 1800 V or less. The frequency is 500 Hz or more and 10000 Hz or less, preferably 1000 or more and 7000 Hz or less, and each can be appropriately selected and used depending on the process. In this case, the waveform of the AC bias for forming the alternating electric field may be a triangular wave, a rectangular wave, a sine wave, or a waveform having a changed duty ratio. In order to cope with a change in the toner image forming speed, development is performed by applying a developing bias voltage having a discontinuous AC bias voltage (intermittent alternating superimposed voltage) to the developer carrier as necessary. Is preferred. If the applied voltage is 300 V or more, a sufficient image density can be easily obtained, and fog toner in the non-image area can be collected well. If the applied voltage is 3000 V or less, the latent image is not disturbed or the image quality is not reduced via the magnetic brush.

By using a two-component developer having a well-charged toner, the fog removal voltage (Vback) can be reduced, and the primary charge of the photoconductor can be reduced, thereby extending the life of the photoconductor. it can. Vback is preferably 200 V or less, more preferably 150 V or less, depending on the development system. The contrast potential is preferably from 100 V to 400 V so that a sufficient image density can be obtained.
If the frequency is lower than 500 Hz, the configuration of the electrostatic latent image bearing photoconductor may be the same as that of the photoconductor normally used in the image forming apparatus, although it is related to the process speed. For example, a photoreceptor having a configuration in which a conductive layer, an undercoat layer, a charge generation layer, a charge transport layer, and a charge injection layer as needed is provided on a conductive substrate such as aluminum or SUS in order.
The conductive layer, the undercoat layer, the charge generation layer, and the charge transport layer may be those usually used for a photoreceptor. As the outermost surface layer of the photoconductor, for example, a charge injection layer or a protective layer may be used.

<Method of Measuring 50% Particle Size (D50) Based on Volume Distribution of Primary Particles of Magnetic Carrier and Magnetic Core>
The particle size distribution was measured by a laser diffraction / scattering type particle size distribution analyzer “Microtrack MT3300EX” (manufactured by Nikkiso Co., Ltd.).
For the measurement of the 50% particle size (D50) based on the volume distribution of the magnetic carrier and the porous magnetic core, a sample supply device for dry measurement, "One-shot dry type sample conditioner Turbotrac" (manufactured by Nikkiso Co., Ltd.) is attached. I went. Turbotrac was supplied under the conditions of a dust collector as a vacuum source, an air flow of about 33 l / sec and a pressure of about 17 kPa. Control is performed automatically on software. As the particle size, a 50% particle size (D50), which is a cumulative value of the volume average, is obtained. Control and analysis are performed using attached software (version 10.3.3-202D). The measurement conditions are as follows.

SetZero time: 10 seconds Measurement time: 10 seconds Number of measurements: once Particle refractive index: 1.81%
Particle shape: Non-spherical measurement upper limit: 1408 μm
Measurement lower limit: 0.243 μm
Measurement environment: temperature 23 ° C, relative humidity 50%

<Method of measuring change in moisture content of magnetic carrier>
The magnetic carrier is weighed in a stainless steel dish with a precision balance by 10 g, and the carrier weight when left for 5 hours in a dryer at a set temperature of 60 ° C. and reduced pressure is defined as W1. Thereafter, the weight of the carrier when the obtained magnetic carrier is allowed to stand for 24 hours in an atmosphere at a temperature of 30 ° C. and a humidity of 80% is defined as W2. The moisture content of the magnetic carrier at this time is defined as A mass%.
Thereafter, the carrier weight when left standing for 24 hours in an environment of a temperature of 23 ° C. and a humidity of 5% is referred to as W3. The moisture content of the magnetic carrier at this time is defined as B mass%.
The change in the water content of the magnetic carrier was calculated according to the following equation (1).
Change in water content of magnetic carrier (% by mass)
= [(W2-W1) x 100 / W1]-[(W3-W1) x 100 / W1]
= [A]-[B]
= (AB) Equation (1)

<Method of measuring resin coating layer thickness of magnetic carrier>
In the method of measuring the thickness of the resin coating layer, the cross section of the magnetic carrier was observed with a transmission electron microscope (TEM) (magnification: 50,000) to measure the thickness of the coating layer.
Specifically, the magnetic carrier was ion-milled using an argon ion milling apparatus (trade name: E-3500, manufactured by Hitachi High-Technologies Corporation), and the magnetic carrier was magnetically extracted with a transmission electron microscope (TEM) (50,000 times). The thickness of the resin coating layer on the cross section of the carrier was arbitrarily measured at 10 points. The same measurement as above was performed for 100 magnetic carriers, and the minimum and maximum values were selected from among the 1000 measured resin coating layer thickness values, and the minimum film thickness (μm) and the maximum film thickness (μm) were selected. ). The ion milling measurement conditions are as follows.

Beam diameter: 400 μm (half width)
Ion gun acceleration voltage: 5 kV
Ion gun discharge voltage: 4 kV
Ion gun discharge current: 463 μA
Ion gun irradiation current amount: 90μA / ^cm 3/1 min

<Method of measuring true density of magnetic carrier and carrier core>
The true density was measured using a dry automatic densimeter auto pycnometer (manufactured by Yuasa Ionics Inc.).

<Measurement of pore diameter and total pore volume of porous magnetic core>
The pore size distribution of the porous magnetic core is measured by a mercury intrusion method.
The measurement principle is as follows.
In this measurement, the pressure applied to mercury is changed, and the amount of mercury that has entered the pores at that time is measured. Assuming that the pressure P, the pore diameter D, the contact angle of mercury and the surface tension are θ and σ, respectively, the conditions under which mercury can enter the pores can be expressed as PD = −4σCOSθ from the balance. Assuming that the contact angle and the surface tension are constants, the pressure P and the pore diameter D into which mercury can enter at that time are inversely proportional. Therefore, the horizontal axis P of the PV curve, which can be measured by changing the pressure P and the amount V of the infiltrated liquid at that time while changing the pressure, is directly replaced with the pore diameter from this equation to determine the pore distribution. I have.

As a measuring device, measurement can be performed using a fully automatic multifunctional mercury porosimeter PoleMaster series / PoleMaster-GT series manufactured by Yuasa Ionics Co., Ltd., an automatic porosimeter autopore IV 9500 series manufactured by Shimadzu Corporation, or the like. it can.
Specifically, the measurement was carried out using Autopore IV9520 manufactured by Shimadzu Corporation under the following conditions and procedures.

Measurement conditions Measurement environment 20 ℃
Measurement cell Sample volume 5cm ³ , Press-fit volume 1.1cm ³ , For powders Measurement range 2.0 psia (13.8 kPa) or more and 59989.6 psia (413.7 kPa) or less Measurement steps 80 steps
(When the pore diameter is logarithmically calculated, the steps are cut so that the intervals are equal.)
Press-in parameter Exhaust pressure 50μmHg
Exhaust time 5.0 minutes
Mercury injection pressure 2.0 psia (13.8 kPa)
Equilibrium time 5 seconds High pressure parameter Equilibrium time 5 seconds Mercury parameter Advance contact angle 130.0 degrees
Receding contact angle 130.0 degrees
Surface tension 485.0 mN / m (485.0 dynes / cm)
Mercury density 13.5335 g / mL

Measurement procedure (1) About 1.0 g of a porous magnetic core is weighed and placed in a sample cell.
Enter the weighing value.
(2) In the low pressure part, a range of 2.0 psia (13.8 kPa) or more and 45.8 psia (315.6 kPa) or less was measured.
(3) In the high-pressure section, a range of 45.9 psia (316.3 kPa) or more and 599989.6 psia (413.6 kPa) or less was measured.
(4) The pore size distribution is calculated from the mercury injection pressure and the mercury injection amount.
(2), (3), and (4) were performed automatically by software attached to the device.
From the pore diameter distribution measured as described above, the pore diameter at which the differential pore volume becomes maximum in the range of pore diameters of 0.1 μm or more and 3.0 μm or less is read, whereby the differential pore volume becomes maximum. Let it be the pore diameter.
Further, the total pore volume obtained by integrating the differential pore volume in the range of the pore diameter of 0.1 μm or more and 3.0 μm or less was calculated using attached software.

<Specific resistance measurement of porous magnetic core>
The specific resistance of the porous magnetic core is measured using a measuring device schematically illustrated in FIG.
FIG. 3A is a diagram showing a blank state before a sample is put, and FIG. 3B is a diagram showing a state when a sample is put. The specific resistance of the magnetic carrier is measured at an electric field strength of 2000 (V / cm) and the electric resistance of the carrier core is measured at a voltage of 300 (V / cm).
The resistance measuring cell A includes a cylindrical container (made of PTFE resin) 17 having a hole having a cross-sectional area of 2.4 cm ² , a lower electrode (made of stainless steel) 18, a support base (made of PTFE resin) 19, and an upper electrode (made of stainless steel). ) 20. The cylindrical container 17 is placed on the support pedestal 19, a sample (magnetic carrier or carrier core) 21 is filled so as to have a thickness of about 1 mm, the upper electrode 20 is placed on the filled sample 21, and the thickness of the sample is reduced. Is measured. As shown in FIG. 3 (a), the gap when there is no sample is d1 (mm), and as shown in FIG. 3 (b), the gap when the sample is filled to a thickness of about 1 mm is d2 (mm). ), The thickness d (mm) of the sample is calculated by the following equation.
d = d2-d1
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 specific resistance of the sample can be obtained by applying a DC voltage between the electrodes and measuring the current flowing at that time. For the measurement, an electrometer 22 (Kesley 6517A manufactured by Kesley) and a processing computer 23 for control are used.
A control system and control software (LabVEIW National Instruments, Inc.) manufactured by National Instruments Co., Ltd. were used for the control processing computer.

As a measurement condition, a value d actually measured 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 is input. The load of the upper electrode is 270 g, and the maximum applied voltage is 1000 V.
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)
As for the specific resistance of the magnetic carrier and the carrier core at the above-mentioned electric field strength, the specific resistance at the above-mentioned electric field strength on the graph is read from the graph. As for the breakdown point, a measured value immediately before the breakdown is used in the obtained graph.

<Method for measuring methanol wettability of hydrophilically treated particles>
0.20 g of the particles subjected to the hydrophilic treatment are precisely weighed in a 500 mL beaker. Subsequently, 50 mL of pure water is added, and while stirring with a magnetic stirrer, while the hydrophilically treated particles are floating on the liquid surface, methanol is continuously added at a dropping rate of 4.0 mL / min below the liquid surface and injected. I do. The total amount of the particles subjected to the hydrophilic treatment was suspended in the solution, and when the particles subjected to the hydrophilic treatment were no longer recognized on the liquid surface, the methanol wettability was calculated using the following equation as an end point. It was an index indicating hydrophilicity.
Methanol wettability (%) = X / (50 + X) · 100
X is the amount of methanol added up to the end point.

<Method for measuring surface functional group concentration of particles>
・ Measurement method of carboxyl group concentration Paste 10 mg of particles on indium foil. At this time, the particles are uniformly attached so that the indium foil portion is not exposed. 1.0 mL of 2,2,2-trifluoroethanol is dropped into a 30 mL screw vial, and the system is saturated with steam. The particles together with the indium foil are put into the system, and the particles are left to stand in a 2,2,2-trifluoroethanol atmosphere for 12 hours in a state where the particles are exposed. At this time, care is taken that the particles do not directly adhere to the 2,2,2-trifluoroethanol solution. The particles were taken out of the system together with the indium foil, and allowed to stand in a dryer at a set temperature of 25 ° C. and reduced pressure for 6 hours. When XPS analysis is performed on the obtained particles, a C1SXPS peak (P1) derived from 2,2,2-trifluoroethyl ester and an XPS peak (P2) derived from the particles are detected. According to 2), the surface functional group concentration of the particles was calculated. The measurement conditions are as follows.
Equipment: PHI5000VERSAPROBEII (ULVAC-PHI, Inc.)
Irradiation line: Al Kd line output: 25W 15kV
PassEnergy: 29.35 eV
Stepsize: 0.125 eV
XPS peak _{(P2): C 1S (CB} ), Ti 2P (TiO 2, SrTiO 2), Al 2P (Al 2 O 3), Si 2P (SiO 2), Mg 2P (MgO), Zn 2P3 / 2 (ZnO )
Particle surface functional group concentration [%] = P1 / P2 × 100 (Equation 2)

-Measuring method of ester group (carbonyl group) concentration An XPS analysis was performed in the same manner as the measurement of ester group (carboxyl group) concentration, except that the reaction reagent was changed from 2,2,2-trifluoroethanol to diamine. went. Since an N1SXPS peak (P3) derived from an imino group was detected, the surface functional group concentration of the particles was calculated according to the following equation (3).
Surface functional group concentration of particles [%] = P3 / P2 × 100 (Equation 3)

<Method of measuring volume average particle diameter of primary particles of inorganic particles or carbon black>
The volume average particle diameter of the primary particles of the hydrophilically treated particles in the present invention was observed with a transmission electron microscope, and the average value of the major axis and the minor axis of the particles was defined as the particle diameter. The particle diameter of 100 particles was measured, and the average value was defined as the volume average particle diameter of the primary particles.

<Method of Measuring Weight Average Particle Size (D4) and Number Average Particle Size (D1) of Toner>
The weight average particle diameter (D4) and the number average particle diameter (D1) of the toner are measured by a precise particle size distribution measuring apparatus “Coulter Counter Multisizer 3” (registered trademark, Beckman KK) equipped with a 100 μm aperture tube by a pore electric resistance method. Coulter Co., Ltd.) and attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (Beckman Coulter Co., Ltd.) for setting measurement conditions and analyzing measurement data were used. The measurement was performed with 25,000 effective measurement channels, and the measured data was analyzed and calculated.

The electrolytic aqueous solution used for the measurement may be a solution prepared by dissolving a special grade sodium chloride in ion-exchanged water to a concentration of about 1% by mass, for example, "ISOTON II" (manufactured by Beckman Coulter, Inc.). .
Before the measurement and analysis, the setting of the dedicated software was performed as follows.
In the “Change standard measurement method (SOM) screen” of the dedicated software, the total count number in the control mode is set to 50,000 particles, the number of measurements is set to 1, and the Kd value is set to “standard particles 10.0 μm” (Beckman Coulter ( The value obtained using the above method is set. By pressing the threshold / noise level measurement button, the threshold and the noise level are automatically set. Also, the current is set to 1600 μA, the gain is set to 2, and the electrolytic solution is set to ISOTON II, and a check mark is placed in the flash of the aperture tube after the measurement.
In the “pulse to particle size conversion setting screen” of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set from 2 μm to 60 μm.
The specific measuring method is as follows.

(1) About 200 mL of the above electrolytic aqueous solution is put into a 250 mL round bottom beaker made of glass exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 revolutions / second. Then, the dirt and air bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.
(2) About 30 mL of the above aqueous electrolytic solution is put into a 100 mL flat bottom glass beaker made of glass. A 10% by mass aqueous solution of a neutral detergent for cleaning a precision measuring instrument having a pH of 7 consisting of a nonionic surfactant, an anionic surfactant and an organic builder was used as a dispersant in the product, Wako Pure Chemical Industries, Ltd. )) Is diluted by 3 times with ion-exchanged water, and about 0.3 mL of a diluent is added.

(3) Two oscillators having an oscillation frequency of 50 kHz are built in with a phase shift of 180 degrees, and are provided in an aquarium of an ultrasonic disperser “Ultrasonic Dispersion System Tetora 150” (manufactured by Nikkaki Bios Co., Ltd.) having an electric output of 120 W. A predetermined amount of ion-exchanged water. About 2 mL of the above contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the aqueous electrolytic solution in the beaker becomes maximum.

(5) While irradiating the ultrasonic wave to the electrolytic solution in the beaker of (4), about 10 mg of toner is added little by little to the electrolytic solution and dispersed. Then, the ultrasonic dispersion processing is continued for another 60 seconds. The ultrasonic dispersion is appropriately adjusted so that the water temperature of the water tank is 10 ° C. or more and 40 ° C. or less.
(6) The aqueous electrolyte solution of (5) above, in which the toner is dispersed, is dropped using a pipette into the round bottom beaker of (1) installed in the sample stand, and the measurement concentration is adjusted to about 5%. . Then, measurement is performed until the number of particles to be measured reaches 50,000.
(7) Analyze the measured data with the dedicated software attached to the apparatus, and calculate the weight average particle diameter (D4) and the number average particle diameter (D1). The “average diameter” on the analysis / volume statistical value (arithmetic average) screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4). The “average diameter” on the analysis / number statistical value (arithmetic average) screen when the graph / number% is set by the dedicated software is the number average particle diameter (D1).

<Calculation method of fine powder amount>
The number-based fine powder amount (number%) in the toner is calculated as follows.
For example, the number% of particles having a particle size of 4.0 μm or less in the toner is measured by the above-mentioned Multisizer 3 and then (1) set to graph / number% with dedicated software and the measurement result chart is displayed as number%. I do. (2) Check “<” in the particle size setting portion on the format / particle size / particle size statistical screen, and enter “4” in the particle size input section below it. When the (3) analysis / number statistical value (arithmetic mean) screen is displayed, the numerical value of the “<4 μm” display portion is the number% of particles of 4.0 μm or less in the toner.

<Calculation method of coarse powder>
The volume-based coarse powder amount (% by volume) in the toner is calculated as follows.
For example, the volume% of particles having a particle size of 10.0 μm or more in the toner is measured by the above-mentioned Multisizer 3, and then (1) the graph / volume% is set by dedicated software, and the chart of the measurement result is displayed as volume%. I do. (2) Check “>” in the particle size setting portion on the format / particle size / particle size statistical screen, and enter “10” in the particle size input section below it. When the (3) analysis / volume statistical value (arithmetic mean) screen is displayed, the numerical value of the “> 10 μm” display portion is the volume% of the particles of 10.0 μm or more in the toner.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<Example of manufacturing porous magnetic core 1>
Process 1 (weighing / mixing process)
68.3% by mass of Fe ₂ O ₃
MnCO ₃ 28.5% by mass
Mg (OH) ₂ 2.0% by mass
SrCO ₃ 1.2 mass%
The ferrite raw material was weighed, 20 parts by mass of water was added to 80 parts by mass of the ferrite raw material, and then wet-mixed for 3 hours with a ball mill using zirconia having a diameter (φ) of 10 mm to prepare a slurry. The solid concentration of the slurry was 80% by mass.

Step 2 (temporary firing step)
The mixed slurry was dried by a spray dryer (manufactured by Okawara Kakoki Co., Ltd.), and then calcined in a batch type electric furnace under a nitrogen atmosphere (oxygen concentration: 1.0% by volume) at a temperature of 1050 ° C. for 3.0 hours, A calcined ferrite was produced.

Step 3 (crushing step)
After the calcined ferrite was pulverized to about 0.5 mm with a crusher, water was added to prepare a slurry. The solid content concentration of the slurry was 70% by mass. The mixture was pulverized with a wet ball mill using 1/8 inch stainless beads for 3 hours to obtain a slurry. Further, this slurry was pulverized for 4 hours by a wet bead mill using zirconia having a diameter of 1 mm to obtain a calcined ferrite slurry having a 50% particle diameter (D50) of 1.3 μm based on volume distribution.

Step 4 (granulation step)
After adding 1.0 part by mass of a polycarboxylate as a dispersant and 1.5 parts by mass of polyvinyl alcohol as a binder to 100 parts by mass of the calcined ferrite slurry, a spray dryer (Okawara Kakoki Co., Ltd. )) And granulated into spherical particles and dried. After the obtained granules were subjected to particle size adjustment, they were heated at 700 ° C. for 2 hours using a rotary kiln to remove organic substances such as dispersants and binders.

Step 5 (firing step)
Under a nitrogen atmosphere (oxygen concentration: 1.3% by volume), the time from room temperature to the firing temperature (1100 ° C.) was set to 2 hours, and the temperature was maintained at 1100 ° C. for 4 hours, and firing was performed. Thereafter, the temperature was lowered to 60 ° C. over 8 hours, returned from the nitrogen atmosphere to the atmosphere, and taken out at a temperature of 40 ° C. or lower.

Process 6 (sorting process)
After crushing the aggregated particles, the particles are sieved with a sieve having an opening of 150 μm to remove coarse particles, air classification is performed to remove fine powder, and low magnetic force components are removed by magnetic separation to remove the porous magnetic core 1. Obtained. The obtained porous magnetic core 1 was porous and had pores. Table 1 shows the manufacturing conditions of each step of the obtained porous magnetic core 1, and Table 2 shows each physical property value.

<Production example of porous magnetic cores 2 to 5>
Among the production examples of the porous magnetic core 1, porous magnetic cores 2 to 5 were produced in the same manner except that the production conditions in each step were changed as shown in Table 1.
Table 1 shows the manufacturing conditions and selection conditions for each step of the obtained porous magnetic cores 2 to 5, and Table 2 shows the physical property values.

<Production Examples of Additional Particles 1 to 5, 7 to 10>
Additive particles 1 were prepared as follows.
100 parts by mass of strontium titanate (trade name: SW540, manufactured by Titanium Industry Co., Ltd.) was put into a rubbed round-bottom flask having a volume of 500 mL, and after the system was made to have a nitrogen atmosphere, 300 parts by mass of anhydrous toluene was added. After cooling with ice, 5 parts by mass of triethylamine, 10 parts by mass of dimethylaminopyridine and 10 parts by mass of acetic anhydride were added, the temperature was raised to 25 ° C., and the mixture was stirred for 2 hours. The reaction was stopped by adding 100 parts by mass of a saturated aqueous solution of sodium hydrogen carbonate, washed with water and a toluene solvent, and air-dried and dried under reduced pressure to obtain chemically modified particles.

100 parts by mass of the obtained chemically modified particles were put into a rubbed round bottom flask having a volume of 500 mL, and 200 parts by mass of methanol was added. After cooling with ice, 30 parts by mass of calcium carbonate was added, the temperature was raised to 25 ° C., and the mixture was stirred for 2 hours. The reaction was stopped by adding 100 parts by mass of a saturated aqueous solution of ammonium chloride, washed with water, and air-dried and dried under reduced pressure to obtain added particles 1.
Except for changing the particles or the treating agent, the same treatment as that of the additional particles 1 was performed to obtain additional particles 2 to 5 and 7 to 10. Table 3 shows the processing conditions for the obtained additive particles 1 to 5 and 7 to 10.

<Production Example of Additive Particle 6>
Additive particles 6 were prepared as follows.
In a rubbed round bottom flask having a volume of 500 mL, 100 parts by mass of carbon black (# 4400, manufactured by Tokai Carbon Co., Ltd.) was placed in a cylindrical ozonizer. Subsequently, 5 parts by mass of ozone was generated per hour by an ozone generator (KQS-120 manufactured by Kotohira Industries Co., Ltd.), and an oxidation treatment was performed for 2 hours while maintaining the treatment temperature at 40 ° C. in an ozone atmosphere. Addition particles 6 were obtained.
Table 3 shows the processing conditions of the obtained additive particles 6.

<Production Example of Additional Particles 11 to 15>
Additive particles 11 were prepared as follows.
100 parts by mass of zinc oxide powder was placed in a rubbed round-bottom flask having a volume of 500 mL, the system was made to have a nitrogen atmosphere, and then 300 parts by mass of anhydrous toluene was added. After cooling with ice, 5 parts by mass of triethylamine, 10 parts by mass of dimethylaminopyridine and 10 parts by mass of formate were added, and the mixture was heated to 25 ° C. and stirred for 2 hours. The reaction was stopped by adding 100 parts by mass of a saturated aqueous solution of sodium hydrogencarbonate, washed with water and a toluene solvent, and air-dried and dried under reduced pressure to obtain added particles 11.
Except for changing the treating agent and the treatment amount, the same treatment as that for the added particles 11 was performed to obtain additional particles 12 to 15. Table 3 shows the processing conditions for the obtained additional particles 11 to 15.

<Additional particles 16>
As the additive particles 16, strontium titanate (trade name: SW540, manufactured by Titanium Industry Co., Ltd.) was used without any special treatment. Table 3 shows the processing conditions for the obtained additive particles 16.
<Production Example of Additive Particle 17>
Additive particles 17 were prepared as follows.
100 parts by mass of strontium titanate (trade name: SW540, manufactured by Titanium Industry Co., Ltd.) was put into a rubbed round-bottom flask having a volume of 500 mL, and after the system was made to have a nitrogen atmosphere, 300 parts by mass of anhydrous dimethylformamide was added. After cooling with ice, 10 parts by mass of imidazole and 10 parts by mass of t-butyldimethylsilyl chloride were added, and the mixture was heated to 25 ° C. and stirred for 20 hours. The reaction was stopped by adding 100 parts by mass of a saturated aqueous solution of sodium hydrogen carbonate, washed with water and a toluene solvent, and air-dried and dried under reduced pressure to obtain added particles 17. Table 3 shows the processing conditions for the obtained additive particles 17.

<Production Examples of Magnetic Carriers 1 to 22>
Step 1 (filling step)
1,100 parts by mass of the magnetic core particles were put into a stirring vessel of a mixing stirrer (universal stirrer NDMV type manufactured by Dalton Co., Ltd.), and nitrogen was introduced while maintaining the temperature at 60 ° C. and reducing the pressure to 2.3 kPa. . Thereafter, the amount of the drop was adjusted so that the solid content of the resin component shown in Table 4 was 5.0 parts by mass with respect to 100 parts by mass of the magnetic core particles, and the resin solution 4 shown in Table 5 was added to the porous magnetic core 1. It was dropped.

After continuing the stirring for 2 hours after the completion of the dropwise addition, the temperature was increased to 70 ° C., the solvent was removed under reduced pressure, and the filler obtained from the resin solution 4 was filled in the particles of the porous magnetic core 1.
After cooling, the obtained filled core particles were transferred to a mixer having a spiral blade (a drum mixer UD-AT type manufactured by Sugiyama Heavy Industries, Ltd.) in a rotatable mixing vessel, and the mixture was heated at 2 ° C. / The temperature was raised to 220 ° C., the set temperature of the stirrer, at a rate of temperature rise for one minute. Heating and stirring were performed at this temperature for 1.0 hour to cure the resin, and stirring was continued for another 1.0 hour while maintaining the temperature at 200 ° C.
Thereafter, the mixture was cooled to room temperature, the ferrite particles filled and cured with the resin were taken out, and the nonmagnetic material was removed using a magnetic separator. Further, coarse particles were removed by a vibrating sieve to obtain resin-filled ferrite particles filled with resin.

Step 2 (resin coating step)
Subsequently, the resin solution 1 shown in Table 6 was charged into a planetary motion type mixer (Nautamixer VN type manufactured by Hosokawa Micron Corp.) maintained at a temperature of 60 ° C. under reduced pressure (1.5 kPa). The amount was adjusted so that the solid content of the resin component shown in Table 4 was 2.0 parts by mass based on 100 parts by mass of the porous magnetic core 1. As a charging method, a 1/3 amount of the resin solution was charged, and the solvent was removed and the coating operation was performed for 20 minutes. Next, a 1/3 amount of the resin solution was further charged, and the solvent removal and coating operation were performed for 20 minutes. Further, a 1/3 amount of the resin solution was charged, and the solvent removal and coating operation were performed for 20 minutes.

Thereafter, the magnetic carrier coated with the resin coating layer composition is transferred to a mixer having a spiral blade (a drum mixer UD-AT type manufactured by Sugiyama Heavy Industries, Ltd.) in a rotatable mixing container. The mixture was heat-treated at a temperature of 120 ° C. for 2 hours in a nitrogen atmosphere while stirring the mixture at 10 rotations per minute. The obtained magnetic carrier 1 was classified into low magnetic products by magnetic separation, passed through a sieve having an opening of 150 μm, and then classified by an air classifier. Magnetic carrier 1 having a 50% particle size (D50) of 39.0 μm based on volume distribution was obtained.
Table 7 shows manufacturing conditions of each step of the obtained magnetic carrier 1, and Table 8 shows physical property values.
Further, magnetic carriers 2 to 22 having the production conditions shown in Table 7 were produced, and their physical property values are shown in Table 8.
Note that the coating process for the magnetic carrier 7 was as follows.

Dry coating step of magnetic carrier 7 As a stirrer, 100 parts by mass of porous magnetic core 1 and solvent were removed from Novirta (manufactured by Hosokawa Micron Corporation), only the resin solid content was taken out, and the weight average particle diameter was further increased. And 5.0 parts by mass of the resin solid content of the resin solution 10 pulverized to 50 μm. In the premixing step, stirring and mixing were performed at the outermost peripheral speed of the stirring member at 1 m / sec for 2 minutes, and thereafter, coating was performed for 15 minutes while adjusting to 10 m / sec to obtain magnetic carrier 7 particles. The obtained magnetic carrier 7 is subjected to magnetic separation to separate low-magnetic-force products, passed through a sieve having an opening of 150 μm, and then classified by an air classifier to obtain a magnetic material having a 50% particle size (D50) of 40.8 μm based on volume distribution. Carrier 7 was obtained. Table 7 shows the manufacturing conditions of each step of the obtained magnetic carrier 7, and Table 8 shows the physical property values.

<Production Example of Toner 1>
-100 parts by mass of binder resin (polyester resin)-C.I. I. Pigment Blue 15: 3 4.5 parts by mass.1,4-di-t-butylsalicylic acid aluminum compound 0.5 part by mass.Normal paraffin wax (melting point: 78 ° C.) 6 parts by mass. (FM-75J type, manufactured by Nippon Coke Industry Co., Ltd.), and then fed at 10 kg / h with a twin-screw kneader (PCM-30, Ikegai Iron & Steel Co., Ltd.) set at a temperature of 130 ° C. (The temperature of the kneaded material at the time of discharge was about 150 ° C.). The obtained kneaded material was cooled, coarsely crushed by a hammer mill, and then finely pulverized by a mechanical grinder (T-250: manufactured by Freund Turbo Co., Ltd.) at a feed rate of 15 kg / hr. Then, particles having a weight average particle size of 5.5 μm, containing 55.6% by number of particles having a particle size of 4.0 μm or less, and containing 0.8% by volume of particles having a particle size of 10.0 μm or more are obtained. Was.

The obtained particles were classified by a rotary classifier (TTSP100, manufactured by Hosokawa Micron Corporation) to cut fine powder and coarse powder. Cyan toner particles 1 having a weight average particle size of 6.4 μm, an abundance of particles having a particle size of 4.0 μm or less being 25.8% by number, and containing 2.5% by volume of particles having a particle size of 10.0 μm or more. I got
Further, the following materials were put into a Henschel mixer (Model FM-75, manufactured by Nippon Coke Industry Co., Ltd.), and the peripheral speed of the rotating blades was set to 35.0 (m / sec). Then, silica and titanium oxide were adhered to the surface of cyan toner particles 1 to obtain cyan toner 1.

100 parts by mass of cyan toner particles 1 3.5 parts by mass of silica (Silica fine particles produced by a sol-gel method are surface-treated with 1.5% by mass of hexamethyldisilazane, and then adjusted to a desired particle size distribution by classification. .)
0.5 parts by mass of titanium oxide (the surface treatment of metatitanic acid having anatase-type crystallinity with an octylsilane compound)

In the cyan toner particles 1, C.I. I. Pigment Blue 15: 3: 5 parts by mass and C.I. I. Pigment Yellow 74: 7.0 parts by mass, C.I. I. Pigment Red 122: 6.3 parts by mass and carbon black: 5.0 parts by mass to obtain yellow, magenta, and black toner particles 1, respectively.
Further, yellow, magenta, and black toners 1 were obtained in the same manner as the cyan toner 1.
Table 9 shows the formulation and physical properties of the obtained toner.

<Example 1>
10 parts by mass of each color toner 1 was added to 90 parts by mass of the magnetic carrier 1, and the mixture was shaken with a shaker (YS-8D: manufactured by Yayoi Co., Ltd.) to prepare 300 g of a two-component developer. The amplitude condition of the shaker was 200 rpm for 2 minutes.
On the other hand, 90 parts by mass of each color toner 1 is added to 10 parts by mass of the magnetic carrier 1, and V-type mixing is performed in a normal temperature and normal humidity (temperature: 23 ° C./relative humidity: 50%; hereinafter also referred to as N / N) environment. The mixture was mixed for 5 minutes by a machine to obtain a replenishing developer.
A drying process was performed on 100 parts by mass of the two-component developer and the replenishing developer while stirring at 25 ° C. in a reduced pressure environment for 5 hours.
The following evaluation was performed using the two-component developer and the replenishing developer.
As the image forming apparatus, a color copier imageRUNNER ADVANCE C9075 PRO remodeling machine manufactured by Canon Inc. was used.
A two-component developer was placed in each color developing device, a replenishment developer container containing the replenishment developer for each color was set, an image was formed, and various evaluations were made.

As a stationary environment of the copying machine, after standing for 24 hours in a temperature of 30 ° C./80% relative humidity (hereinafter also referred to as HH) environment, a temperature of 23 ° C./5% relative humidity (hereinafter also referred to as NL). ) Is assumed to be H / Ha when changed over 24 hours.
As an endurance test, an FFh output chart with an image ratio of 40% was used in an HH environment. FFh is a value in which 256 gradations are displayed in hexadecimal notation, 00h is the first gradation (white background) of 256 gradations, and FFh is the 256th gradation (solid part) of 256 gradations. .
The type of output image and the number of output images were changed depending on each evaluation item.

conditions:
Paper Laser beam printer paper CS-814 (81.4 g / m ² )
(Canon Marketing Japan Inc.)
Image formation speed Modified to output A4 size, full color at 80 (sheets / min).
Development conditions The development contrast can be adjusted to an arbitrary value, and automatic correction by the main unit is activated.
Modified to not.
The voltage (Vpp) between the peaks of the alternating electric field has a frequency of 2.0 kHz and Vpp.
Modified so that it can be changed from 0.7 kV to 1.8 kV in steps of 0.1 kV
Was.
Each color was modified so that it could output images in a single color.
Each evaluation item is shown below.

(1) White spots Initially in the H / Ha environment, and immediately after 2,000 sheets of continuous paper passing, halftone horizontal bands (30h width 10 mm) and solid horizontal bands (FFh width 10 mm) alternate with respect to the transport direction of the transfer paper. Output the chart arranged in. 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 is drawn to the halftone luminance at that time, and the area of the luminance (area: sum of the number of luminances) deviating from the tangent at the rear end of the halftone part until it intersects with the solid part luminance is defined as the degree of blank area. It evaluated based on. The evaluation was performed for cyan monochromatic.

A: less than 20 B: 20 or more and less than 30 C: 30 or more and less than 40 D: 40 or more and less than 50 E: 50 or more

(2) Change in Gradation under H / Ha Environment In the H / Ha environment state, ten images in which each pattern is set to the following density are output. The average value of the patterns of the ten images is calculated by using an X-Rite color reflection densitometer (X-Rite 404A).
Pattern 1: 0.10 to 0.15
Pattern 2: 0.25 to 0.30
Pattern 3: 0.45 to 0.50
Pattern 4: 0.65 to 0.70
Pattern 5: 0.85 to 0.90
Pattern 6: 1.05-1.10
Pattern 7: 1.25 to 1.30
Pattern 8: 1.45 to 1.50

The criteria are as follows.
A: All pattern images satisfy the above density range B: One pattern image deviates from the above density range C: Two pattern images deviate from the above density range D: Three pattern images become the above density range Out of range E: Four or more pattern images are out of the above density range.

(3) Variation in color tint after endurance The variation in tint of red, which is a color mixture of yellow and magenta, was evaluated.
Before the endurance test, the development contrast was adjusted so that the solid image reflection density on a single color paper was 1.5. After outputting an initial red solid image under the HH environment, a red solid image immediately after continuous printing of 20,000 sheets was output, and the degree of color change before and after running was confirmed.

<Measurement method of color variation difference>
The tint variation difference is determined by measuring a ^* and b ^* using a SpectroScan Transmission (manufactured by GretagMacbeth). An example of specific measurement conditions is shown below.

(Measurement condition)
Observation light source: D50
Observation field: 2 °
Concentration: DIN NB
White standard: Pap
Filter: None

Generally, a ^* and b ^* are values used in the L ^* a ^* b ^* color system, which is a useful means for expressing colors in numerical form. a ^* and b ^* both represent hue. Hue is a measure of hue, such as red, yellow, green, blue, and purple. Each of a ^* and b ^* indicates a color direction, where a ^* indicates a red-green direction and b ^* indicates a yellow-blue direction. In the present invention, the difference (ΔC) of the tint fluctuation is defined as follows.
[Delta] C = {(initial image a ^* -HH environmental durability after image HH environment a ^{*) 2}
+ (B initial image b ^* -HH environmental durability after image HH environment ^{*) 2} 1/2}
In the measurement, five arbitrary points in the image were measured, and the average value was obtained. As an evaluation method, a ^* and b ^* of a solid image output in each environment were measured, and ΔC was obtained by the above equation.

A: 0 ≦ ΔC <2.0
B: 2.0 ≦ ΔC <3.5
C: 3.5 ≦ ΔC <5.0
D: 5.0 ≦ ΔC <6.5
E: 6.5 ≦ ΔC

(4) Carrier Adhesion After Endurance After the endurance image output evaluation under the HH environment was performed, the carrier adhesion was evaluated. The 00H image and the FFh image were output, the power was turned off during the image output, and a transparent adhesive tape was stuck on the electrostatic latent image carrier before cleaning, and sampling was performed. Then, the number of magnetic carrier particles adhering on the electrostatic latent image carrier in 3 cm × 3 cm was counted, and the number of adhering carrier particles per 1 cm ² was calculated and evaluated according to the following criteria. The evaluation was performed for cyan monochromatic.

A: 2 or less B: 3 or more and 4 or less C: 5 or more and 6 or less D: 7 or more and 8 or less E: 9 or more

(5) Roughness after halftone image durability After performing initial and durability image output evaluations (50,000 sheets) in an HH environment, one halftone image (30H) was printed in A4. For the image, the area of 1,000 dots was measured using a digital microscope VHX-500 (lens wide range zoom lens VH-Z100 manufactured by Keyence Corporation). The number average (S) of the dot areas and the standard deviation (σ) of the dot areas were calculated, and the dot reproducibility index was calculated by the following equation. Then, the roughness of the halftone image was defined as a dot reproducibility index (I), and the difference from the initial stage was compared.
Dot reproducibility index (I) = σ / S × 100
The evaluation criteria for roughness were cyan single color and evaluated according to the following criteria.

A: Difference from the initial stage is less than 3.0 B: Difference from the initial stage is 3.0 or more and less than 5.0 C: Difference from the initial stage is 5.0 or more and less than 8.0 D: Difference from the initial stage is 8.0. 0 or more and less than 10.0 E: Difference from the initial value is 10.0 or more

(6) Developability after endurance The evaluation of the endurance developability was made under the HH environment with the initial Vpp fixed at 1.3 kV and the contrast potential when the density of a solid cyan monochrome image became 1.50 (reflection density). It was set.
After durability of 20,000 sheets under these settings, the contrast potential at which Vpp was 1.3 kV and the image density was 1.50 was obtained, and the difference from the initial value was compared. The evaluation was performed for cyan monochromatic.
The reflection density was measured using a spectrodensitometer 500 series (manufactured by X-Rite).
Evaluation criteria for developability

A: Difference from initial, less than 40 V B: Difference from initial, 40 V or more and less than 60 V C: Difference from initial, 60 V or more and less than 80 V D: Difference from initial, 80 V or more and less than 100 V E: Initial Is 100V or more

(7) Change in gradation before and after endurance In the initial setting, an image in which each pattern is set to the following density is output immediately after 2,000 sheets are passed in an HH environment. A shift in gradation was confirmed. The images were judged by measuring the respective image densities with an X-Rite color reflection densitometer X-Rite 404A. The evaluation was performed for cyan monochromatic.

Pattern 1: 0.10 to 0.13
Pattern 2: 0.25 to 0.28
Pattern 3: 0.45 to 0.48
Pattern 4: 0.65 to 0.68
Pattern 5: 0.85 to 0.88
Pattern 6: 1.05 to 1.08
Pattern 7: 1.25 to 1.28
Pattern 8: 1.45 to 1.48
The criteria are as follows.

A: All pattern images satisfy the above density range B: One pattern image deviates from the above density range C: Two pattern images deviate from the above density range D: Three pattern images become the above density range Out of range E: Four or more pattern images are out of the above density range.

(8) Comprehensive Judgment The evaluation ranks in the evaluation items (1) to (7) were quantified, and the total value was judged according to the following criteria. The evaluation rank other than the evaluation item (6) is “A = 5, B = 4, C = 3, D = 2, E = 0”, and the evaluation rank of the evaluation item (6) is “A = 10 , B = 8, C = 6, D = 4, E = 2. "

A: 35 or more B: 28 or more and 34 or less C: 20 or more and 27 or less D: 15 or more and 19 or less E: 14 or less In Example 1, any evaluation was a very good result. Table 10 shows the evaluation results.

<Examples 2 to 6>
Similarly to Example 1, a two-component developer and a replenishing developer were prepared in the same ratio as in Example 1 using magnetic carriers 2 to 6. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
In Examples 2 to 6, the types of the added particles were different from those in Example 1, but in all the evaluations, very good results were obtained. Table 10 shows the evaluation results.

<Example 7>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 7 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 7 was different from Example 1 in that two types of additive particles were contained, but in each evaluation, very good results were obtained. Table 10 shows the evaluation results.

<Example 8>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 8 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 8 differs from Example 1 in the resin type of the resin coating layer. The use of a polystyrene resin for the resin coating layer slightly affected white spots and gradation changes in an NL environment. In addition, the color tone after durability in the HH environment and the roughness of the halftone image were slightly affected, but all evaluations were favorable. Other evaluations were very good. Table 10 shows the evaluation results.

<Example 9>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 9 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 9 differs from Example 8 in the type of resin of the filler. The use of a polystyrene resin as the filler slightly affected white spots and gradation changes in an NL environment. In addition, the color tone after durability in the HH environment and the roughness of the halftone image were slightly affected, but all evaluations were favorable. Other evaluations were very good. Table 10 shows the evaluation results.

<Example 10>
As in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 10 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
In Example 10, as compared with Example 9, the thickness of the resin coating layer was small, and the mass part of the added particles was small. Further, the average diameter of the added particles is small. As a result, white spots and gradation changes in the NL environment were affected, but all evaluations were somewhat favorable. Further, in the reduction of the charging characteristics in the HH environment, the color tone after the durability, the carrier adhesion, the roughness of the halftone image, the developability, and the gradation change before and after the durability were slightly affected. Good results. Table 10 shows the evaluation results.

<Example 11>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 11 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
In Example 11, as compared with Example 9, the resin coating layer had a larger thickness and the added particles had more parts by mass. Further, the average diameter of the added particles is large. As a result, white spots and gradation changes in the NL environment were affected, but all evaluations were somewhat favorable. In addition, the color tone after the durability in the HH environment, the carrier adhesion, the roughness of the halftone image, the developability, and the gradation change before and after the durability were slightly affected, but all the evaluations were favorable. Table 10 shows the evaluation results.

<Example 12>
As in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 12 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 12 differs from Example 11 in the types of added particles, functional group, thickness of the resin coating layer, parts by mass of added particles, and average diameter of added particles. As a result, white spots and gradation changes in the NL environment were affected, but all evaluations were somewhat favorable. In addition, the color tone after durability in the HH environment, the roughness of the halftone image, and the developability were affected, but all evaluations were slightly favorable. All other evaluations were favorable. Table 10 shows the evaluation results.

<Example 13>
As in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 13 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 13 is different from Example 11 in the types of the added particles, the functional group, the thickness of the resin coating layer, the mass parts of the added particles, and the average diameter of the added particles. As a result, white spots and gradation changes in the NL environment were affected, but all evaluations were somewhat favorable. In addition, the color tone after durability in the HH environment, the roughness of the halftone image, and the developability were affected, but all evaluations were slightly favorable. Other evaluations were good results. Table 10 shows the evaluation results.

<Example 14>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 14 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 14 differs from Example 13 in the hydrophilic treatment of the added particles. As a result of the decrease in the functional group concentration of the added particles, white spots and gradation changes in the NL environment were affected, but all evaluations were somewhat favorable. Further, the color tone after the durability in the HH environment, the carrier adhesion, the roughness of the halftone image, the developability, and the gradation change before and after the durability were affected, but all the evaluations were somewhat favorable. Table 10 shows the evaluation results.

<Example 15>
Similarly to Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 15 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 15 differs from Example 14 in the functional group concentration on the surface of the added particles. The low functional group concentration affected white spots in an NL environment, but was at a level that was no problem. Other than that, all the evaluations were slightly good results. Table 10 shows the evaluation results.

<Example 16>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 16 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 16 is different from Example 15 in that the functional group concentration on the surface of the added particle is lower. The low functional group concentration affected white spots in an NL environment, but was at a level that was no problem. In addition, the color and durability after durability in an HH environment were affected, but at a level that was not a problem. Other than that, all the evaluations were slightly good results. Table 10 shows the evaluation results.
In addition, Example 16 and Examples 17 and 18 described below are described as reference examples.

<Example 17>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 17 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 17 is different from Example 16 in that methanol wettability is high. High methanol wettability affected white spots in an NL environment, but at a level that was no problem. In addition, the color tone after durability in the HH environment, the roughness of halftone images, the developability, and the gradation difference before and after durability were affected, but at a level that was no problem. Other than that, all the evaluations were slightly good results. Table 10 shows the evaluation results.

<Example 18>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 18 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Example 18 is different from Example 17 in that methanol wettability is higher. The high methanol wettability affected the gradation change in the NL environment, but at a level that was no problem. Table 10 shows the evaluation results.

<Comparative Example 1>
Similarly to Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 19 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Comparative Example 1 is different from Example 1 in that no hydrophilic treatment was performed on the added particles. As a result, white spots in the NL environment deteriorated. In addition, the color tone after durability in the HH environment, the roughness of halftone images, and the level of developability were reduced. Table 10 shows the evaluation results.

<Comparative Example 2>
In the same manner as in Example 1, a two-component developer and a replenishing developer were prepared using the magnetic carrier 20 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Comparative Example 2 is different from Example 1 in that the additive particles are subjected to a hydrophobic treatment. As a result, white spots and gradation changes in the NL environment were deteriorated. In addition, the color tone after durability in the HH environment, the roughness of halftone images, and the level of developability were reduced. Table 10 shows the evaluation results.

<Comparative Example 3>
In the same manner as in Example 3, a two-component developer and a replenishing developer were prepared using the magnetic carrier 21 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.
Comparative Example 3 is different from Example 1 in that no filler particles are contained in the filler. As a result, white spots in the NL environment deteriorated. In addition, the color tone after durability in the HH environment, the roughness of halftone images, and the level of developability were reduced. Table 10 shows the evaluation results.

1, 1K, 1Y, 1C, 1M: electrostatic latent image carrier, 2, 2K, 2Y, 2C, 2M: charger, 3, 3K, 3Y, 3C, 3M: exposure unit, 4, 4K, 4Y, 4C , 4M: developing device, 5: developing container, 6, 6K, 6Y, 6C, 6M: developer carrier, 7: magnet, 8: regulating member, 9: intermediate transfer member, 10K, 10Y, 10C, 10M: intermediate Transfer charger, 11: transfer charger, 12: transfer material (recording medium), 13: fixing device, 14: intermediate transfer body cleaner, 15, 15K, 15Y, 15C, 15M: cleaner, 16: pre-exposure, 40: Magnetic carrier, 41: porous magnetic particles, 42: filler, 43: filled magnetic core particles, 44: resin coating layer, 45: resin, 46: particles subjected to hydrophilic treatment

Claims (12)

Porous magnetic particles, filled magnetic core particles having a filler present in the pores of the porous magnetic particles, and a resin coating layer present on the surface of the filled magnetic core particles,
A magnetic carrier having
The filler is
(I) a resin;
(Ii) oxide particles of a metal element having an ester group and / or a carboxyl group on the surface, silica particles having an ester group and / or a carboxyl group on the surface , and carbon black having an ester group and / or a carboxyl group on the surface. and one or two or more particle element selected from the group consisting,
Contain,
The particles (ii) have a methanol wettability of 49 to 78% and a functional group concentration of the ester group and / or the carboxyl group of 20 to 71%.
A magnetic carrier, characterized in that: Oxide particles prior Kikin group element _{is, TiO 2, Al 2 O 3} , MgO and the magnetic carrier of claim 1 wherein the oxide particles of one or two or more metal elements selected from SrTiO _3. The volume average diameter of the primary particles of the particles of (ii), the magnetic carrier of claim 1 or 2 is 10nm or more 1000nm or less. The magnetic material according to any one of claims 1 to 3 , wherein the filler contains the particles of (ii) in an amount of from 1.0 part by mass to 20.0 parts by mass when the resin is 100 parts by mass. Career. Thickness of the resin coating layer, the magnetic carrier according to any one of claims 1-4 is 0.01μm or 4.00μm or less. The magnetic carrier according to any one of claims 1 to 5 , wherein the filler is a polymer and / or a silicone resin obtained by polymerizing a monomer containing a (meth) acrylate monomer. The magnetic carrier according to any one of claims 1 to 6 , wherein the resin coating layer contains a polymer obtained by polymerizing a monomer containing a (meth) acrylate monomer. The moisture content of the magnetic carrier when left standing for 24 hours in an environment of a temperature of 30 ° C. and a humidity of 80% is A mass%,
When the magnetic carrier was left standing for 24 hours in an environment of a temperature of 23 ° C. and a humidity of 5% after standing for 24 hours in an environment of a temperature of 30 ° C. and a humidity of 80%, and the moisture content of the magnetic carrier was B mass%.
The magnetic carrier according to any one of claims 1 to 7 , wherein a change in moisture content (A-B) mass% is 0.03 mass% or less. A two-component developer containing a binder resin, a toner having toner particles containing a colorant and a release agent, and a magnetic carrier,
A two-component developer, wherein the magnetic carrier is the magnetic carrier according to any one of claims 1 to 8 . A charging step of 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, and the electrostatic latent image using a two-component developer. A developing step of developing to form a toner image, a transferring step of transferring the toner image to a transfer material with or without an intermediate transfer member, and a fixing step of fixing the transferred toner image to the transfer material An image forming method having
An image forming method using the two-component developer according to claim 9 as the two-component developer. A charging step of 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, and a two-component system developing the electrostatic latent image in a developing device Developing using a developer to form a toner image, transferring the toner image to a transfer material with or without an intermediate transfer member, and fixing the transferred toner image to the transfer material. In accordance with the reduction of the toner concentration of the two-component developer in the developing device, a replenishing developer is supplied to the developing device, and the excess magnetic carrier is developed in the developing device as necessary. A replenishing developer for use in an image forming method discharged from a container,
The replenishment developer contains a replenishment magnetic carrier, a toner having toner particles containing a binder resin, a colorant and a release agent,
The replenishing developer contains 2 to 50 parts by mass of the toner based on 1 part by mass of the replenishing magnetic carrier,
A replenishing developer, wherein the replenishing magnetic carrier is the magnetic carrier according to any one of claims 1 to 8 . A charging step of 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, and a two-component system developing the electrostatic latent image in a developing device Developing using a developer to form a toner image, transferring the toner image to a transfer material with or without an intermediate transfer member, and fixing the transferred toner image to the transfer material. In accordance with the reduction of the toner concentration of the two-component developer in the developing device, a replenishing developer is supplied to the developing device, and the excess magnetic carrier is developed in the developing device as necessary. An image forming method discharged from a container,
The replenishment developer contains a replenishment magnetic carrier and a binder resin, a toner having toner particles containing a colorant and a release agent,
The replenishing developer contains 2 to 50 parts by mass of the toner based on 1 part by mass of the replenishing magnetic carrier,
An image forming method, wherein the replenishing magnetic carrier is the magnetic carrier according to any one of claims 1 to 8 .

Images