JP2008256840A - Developer for electrostatic latent image development, developer cartridge for electrostatic latent image development, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer for electrostatic latent image development, the developer that prevents peeling or scraping in a coating resin layer and deposition of inorganic particles as an external additive to a carrier in stirring a toner and a carrier in repeated development for a long period of time, that has excellent transfer property, carrier contamination preventing property and stable charging performance and that can stably form an image for a long period of time. <P>SOLUTION: The developer for electrostatic latent image development contains a toner composition comprising toner particles containing at least a colorant and a binder resin and inorganic particles, and a carrier comprising core particles and a coating resin layer coating the surface of the core particles, wherein the coating resin layer comprises a specified polycarbonate resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developer for developing an electrostatic latent image, a developer cartridge for developing an electrostatic latent image, a process cartridge, and an image forming apparatus.

  Methods for visualizing image information through an electrostatic charge image such as electrophotography are currently used in various fields. Conventionally, in electrophotography, an electrostatic latent image is formed on a photosensitive member or an electrostatic recording body by using various means, and electro-sensitive fine particles called toner are attached to the electrostatic latent image, thereby static electricity. A method of developing and visualizing an electrostatic latent image is generally used.

  The developer used here is a two-component developer that imparts an appropriate amount of positive or negative charge to the toner by triboelectrically charging both the carrier particles called the carrier and the toner, and a toner such as a magnetic toner. It is roughly classified into a one-component developer used alone. In particular, the two-component developer has functions such as agitation, conveyance, and charging imparted to the carrier itself, and the functions required for the developer can be separated, so that the design is easy. Currently widely used.

In the currently mainstream two-component developers, there is generally a method of setting the developing sleeve peripheral speed faster than the photosensitive member peripheral speed in order to ensure a sufficient image density, that is, to supply a sufficient developer to the developing area. Commonly used.
However, development defects caused by the relative speed difference between the developing sleeve and the photosensitive member, for example, a solid image trailing edge missing, a halftone and a solid image coexisting, and after the halftone image at the leading edge of the solid image and the halftone boundary portion It is known that end missing or the like occurs.

For the purpose of suppressing these image defects, it has been proposed to suppress the electric resistance of the carrier low in order to improve the trailing edge of the solid image (Patent Document 1). However, when the resistance of the developer or carrier is lowered to improve the image defect, the effect of the proximity of the developing effective electrode to the photosensitive member is reduced, and the ability to supply toner to the photosensitive member is reduced, and an image caused by latent image leakage occurs. It is known that defects such as those swept by brushes are likely to occur.
For this reason, a lower limit value of the resistance of the carrier layer for improving the image defect has been proposed (for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  In general, the amount of charge required for a developer is easily affected by temperature, humidity, and the like. Therefore, in order to suppress the change in chargeability based on such environmental fluctuation, a specific aromatic polycarbonate resin, the resin and styrene, A carrier coated with a copolymer with an aliphatic monocarboxylic acid, vinyl ether, polyester or the like has been proposed (Patent Document 4).

  On the other hand, with the recent demand for higher image quality, the particle size of the toner has been reduced, and the non-electrostatic adhesion between the toner and the photoreceptor has become stronger, making it difficult to transfer. For this reason, methods have been proposed in which the shape of the toner is controlled or an external additive is added as a spacer agent to the outside of the toner to suppress the contact force between the toner and the surface of the photoreceptor (Patent Documents 5 and 6). However, the external additive on the toner surface may be embedded in the toner by stirring in the developing machine for a long period of time, and may not function sufficiently as a spacer agent.

  Therefore, it has been disclosed that it is effective to use inorganic particles having a large particle diameter in order to suppress the burying of the external additive in the toner (Patent Document 7, Patent Document 8, and Patent Document 9).

Japanese Patent Publication No. 7-31422 Japanese Patent Publication No. 6-29992 Japanese Patent Publication No. 5-40309 JP 7-319217 A Japanese Patent Laid-Open No. 4-337738 JP-A-4-337742 JP-A-7-28276 JP-A-9-31913 Japanese Patent Laid-Open No. 10-312089

In general, the resistance of the developer is substantially determined by the resistance of the carrier and the coverage of the toner on the surface of the carrier. Furthermore, since the resistance of the developer has an electric field dependence, especially in a full color image in which various types of latent image levels are continuously mixed, in order to avoid the above-described development defect, the resistance of the carrier and the surface of the carrier It is necessary to control the toner coverage.
However, if the development is repeated over a long period of time, the charging ability of the carrier decreases due to peeling or scraping of the coating resin layer of the carrier or adhesion of the toner component to the carrier surface. Then, in order to secure the image density, the amount of charge per toner is reduced, so that fogging occurs. Conversely, if the amount of charge of the toner is to be secured, the amount of toner in the developer is decreased. Inevitably, the image density is lowered.

  In addition, image loss due to the relative speed difference between the developing sleeve and the photosensitive member in the two-component developer is dependent on the latent image structure in the amount of change in the developer layer potential due to toner movement in the development contact area in the development process. In the case where development is performed with a further difference in speed, development is performed with a developer that has received an electric field history immediately before the latent image to be developed in the region where development is actually performed. On the other hand, for example, it is considered that the trailing edge of the image becomes conspicuous at the boundary between the solid image and the non-image part or at the halftone and solid image boundary part.

  Further, as in Reference 4, the coating resin layer containing a polycarbonate resin cannot sufficiently prevent adhesion of the toner component to the carrier and may not sufficiently maintain the charging ability of the carrier.

  Further, as described in Reference 8, when the particle size of the inorganic particles is increased, the inorganic particles have a large true specific gravity, and thus the inorganic particles may be detached from the toner surface by stirring in the developing device. At that time, the detached inorganic particles adhere to the carrier surface and reduce the charging ability of the carrier. Furthermore, when a stirring stress is applied with the inorganic particles attached to the carrier surface, the inorganic particles tend to damage the coating resin layer of the carrier and cause the coating resin layer to be scraped. As a result, a coating resin layer adheres to the photoconductor, and the surface of the photoconductor is not locally charged, generating a so-called color point that is developed regardless of the subsequent exposure, in other words, regardless of the latent image. There was a case where I was allowed to.

  As described above, a developer that sufficiently suppresses adhesion of the toner component to the carrier and peeling or scraping of the coating resin layer, has stable charging performance for a long time, and provides high image quality for a long time has not yet been provided. There is no current situation.

  The present invention prevents the peeling and scraping of the coating resin layer and the adhesion of inorganic particles as external additives to the carrier in the stirring of the toner and the carrier in repeated development over a long period of time, and provides excellent transferability and carrier contamination resistance. It is an object of the present invention to provide a developer for developing an electrostatic latent image, which has a property and stable charging performance and can stably form an image over a long period of time.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> a toner composition having at least a colorant and a binder resin, an inorganic particle, and a carrier having a core material particle and a coating resin layer covering the surface of the core material particle, The coating resin layer includes a copolymer obtained by polymerizing at least a polymerizable monomer represented by the following general formula (I) and a polymerizable monomer represented by the following general formula (II); A developer for developing an electrostatic latent image, wherein the copolymer has a copolymerization ratio of 20/80 to 80/20.

  <2> The developer for developing an electrostatic latent image according to <1>, wherein the inorganic particles have a volume average particle diameter of 0.05 μm or more and 0.35 μm or less.

<3> The developer for developing an electrostatic latent image according to <1> or <2>, wherein the core particle satisfies the following formula (1).
Formula (1): 3.5 <= A / a <= 6.5
[Wherein, in formula (1), A represents the BET specific surface area (unit: m ² / g) of the core particle, a represents the spherical equivalent specific surface area (unit: m ² / g) of the core particle, The spherical equivalent specific surface area a is defined as a = 6 / (d, where d (unit: μm) is the volume average particle diameter of the core particles and ρ (unit: dimensionless) is the true specific gravity of the core particles. Xρ). ]

  <4> A developer that is detachable from the image forming apparatus and contains at least developer for developing the electrostatic latent image formed on the surface of the electrostatic latent image holding member to form a toner image is stored. A developer cartridge for developing an electrostatic latent image, wherein the developer is the developer for developing an electrostatic latent image according to any one of <1> to <3>.

  <5> The developer for developing an electrostatic latent image according to any one of <1> to <3> is accommodated, and the electrostatic latent image formed on the surface of the electrostatic latent image holding member is stored in the electrostatic latent image. Developing means for developing a toner image by developing with a charge latent image developing developer, an electrostatic latent image holding member, a charging means for charging the surface of the electrostatic latent image holding member, and the electrostatic latent image holding A process cartridge comprising: at least one selected from the group consisting of cleaning means for removing toner remaining on the surface of the body, and being detachable from the image forming apparatus.

  <6> At least an electrostatic latent image holding member, charging means for charging the surface of the electrostatic latent image holding member, and electrostatic latent image formation for forming an electrostatic latent image on the surface of the electrostatic latent image holding member Developing means for developing the electrostatic latent image with a developer to form a toner image; transfer means for transferring the toner image to a recording medium; and fixing means for fixing the toner image to the recording medium; And the developer is an electrostatic latent image developing developer according to any one of <1> to <3>.

According to the present invention, in the stirring of the toner and the carrier during repeated development over a long period of time, the coating resin layer is prevented from being peeled off or scraped, and the inorganic particles as external additives are prevented from adhering to the carrier, and excellent transferability and resistance It is possible to provide a developer for developing an electrostatic latent image having carrier contamination and stable charging performance and capable of forming an image stably over a long period of time.
Furthermore, according to the present invention, a developer cartridge for developing an electrostatic latent image, a process cartridge, and an image forming apparatus using the developer for developing an electrostatic latent image can be provided.

[Developer for developing electrostatic latent image]
The developer for developing an electrostatic latent image of the embodiment covers a toner composition having toner particles including at least a colorant and a binder resin and inorganic particles, core particles, and the surfaces of the core particles. A carrier having a coating resin layer, the coating resin layer comprising at least a polymerizable monomer represented by the following general formula (I) and a polymerizable monomer represented by the following general formula (II): And a copolymer ratio of 20/80 to 80/20. The copolymer is characterized in that the copolymer has a copolymerization ratio of 20/80 to 80/20.

The reason why the above problem is solved by adopting the above configuration has not been clarified in detail, but can be considered as follows.
Many of the external additives used as the spacer agent are inorganic particles such as silica, and are particularly hard components among the developer components. Therefore, when forming an image over a long period of time, under conditions where the developer is continuously stirred in the developing means, the external additive is detached from the toner surface and adheres to the carrier surface, and at the same time, the coating resin layer is scratched and coated. The transfer of the resin layer to the photoconductor occurs.

  Since the transfer of the external additive to the carrier occurs due to the collision between the external additive released from the toner and the carrier, it can be improved by preventing the release from the toner and improving the impact resistance of the resin layer covering the carrier. .

  As the carrier, a coating resin layer having excellent impact resistance is required. The above-mentioned specific polycarbonate resin exhibits sufficient charging characteristics and excellent surface wettability, so that excellent adhesion can be obtained when coated on core particles, the coated resin layer is difficult to peel off, and excellent impact resistance Therefore, the surface of the coating resin layer is hardly scraped. In a more preferred embodiment, the surface of the core material particle surface is increased by providing appropriate irregularities on the surface of the core material particle, and at the same time, the resin is infiltrated into the concave portion of the surface of the core material particle, and the coating resin layer and the surface of the core material particle It is possible to impart an effect of adding to the coating resin layer, that is, a throwing effect to the coating resin layer.

  Here, by using the specific polycarbonate resin for the coating resin layer, the excellent surface wettability of the polycarbonate resin sufficiently penetrates into the recesses on the surface of the core material particles, and a relatively uniform coating resin layer is formed. At this time, the specific polycarbonate resin exhibits excellent flexibility, and even when the external additive on the toner surface and the carrier are contacted and stirred, the external additive is prevented from adhering to the carrier surface.

  Furthermore, as a more preferable aspect, as an external additive, it is good to prescribe | regulate optimal volume average particle diameter. For example, when an external additive having a small particle size is used, the non-electrostatic adhesion to the toner is increased and it is difficult to release, but the toner is easily embedded and the carrier when released is used. There is also a tendency for adhesion to the skin to become stronger. When an external additive having a large particle size is used, adhesion to the carrier is weakened, but it is easily released from the toner, and the effect as a spacer agent may not be maintained.

As a still more preferable embodiment, a further effect can be obtained by combining a coated resin carrier in which the specific polycarbonate resin is coated on core particles having moderate irregularities and an external additive having an optimal volume average particle diameter. The present inventors have found out.
Hereinafter, each component of the present embodiment will be described.

[Carrier]
<Core particles>
The core particles of the embodiment preferably satisfy the following formula (1).
Formula (1): 3.5 <= A / a <= 6.5
[In the formula (1), A represents the BET specific surface area (unit: m ² / g) of the core material particles, a represents the spherical equivalent specific surface area (unit: m ² / g) of the core material particles, The spherical equivalent specific surface area a is defined as a = 6 / (d, where d (unit: μm) is the volume average particle diameter of the core particles and ρ (unit: dimensionless) is the true specific gravity of the core particles. Xρ). ]

The BET specific surface area is a specific surface area per unit mass determined by the BET method, and the spherical equivalent specific surface area a is a specific surface area per unit mass when the core material particles are assumed to be completely smooth spheres.
Therefore, the value of (A / a) represents irregularities on the surface of the core material particles. That is, the larger the value of (A / a), the greater the irregularities on the surface of the core material particles, and the smaller the value of (A / a), the smoother the surface of the core material particles.

  With this configuration, the core particles and the coating resin layer can be made more difficult to peel.

  By adding moderate irregularities to the core particle surface, the surface area of the core particle is expanded, and at the same time, the resin is infiltrated into the concave portion of the core particle surface, and the effect of adding the coating resin layer and the core particle surface is caught. That is, the anchor effect can be imparted to the coating resin layer. Thereby, it becomes possible to suppress peeling of the coating resin layer.

  When the core particle (A / a) is smaller than 3.5, the coating resin layer and the core particle are caught, that is, the anchor effect to the resin due to the surface irregularity of the core particle is small, so the uniform coating resin layer May not be obtained, and the flexibility of the specific polycarbonate resin may be impaired. In addition, if the core particle (A / a) is larger than 6.5, the resin penetrates into the core particle, so that the core particle is exposed on the carrier surface and the carrier resistance may be too low. is there.

The core material particles used in the carrier of the embodiment more preferably satisfy the following formula (2), and particularly preferably satisfy the following formula (3).
Formula (2): 4.0 ≦ A / a ≦ 6.0
Formula (3): 4.5 <= A / a <= 5.5

The BET specific surface area A (m ² / g) of the core particles in the embodiment is measured by the following method.
Using a BET specific surface area meter (SA3100, manufactured by Beckman Coulter, Inc.) as a measuring device, 0.1 g of a porous silicon nitride fine powder as a measurement sample is precisely weighed and placed in a sample tube, and then degassed. The numerical value obtained by the point method automatic measurement is defined as the BET specific surface area A of the core material particles.

The spherical equivalent specific surface area a (m ² / g) of the core particles is represented by the following formula (4).
Formula (4): a = 6 / (d × ρ)
Here, d is the volume average particle size (unit: μm) of the core material particles, and ρ is the true specific gravity (unit: dimensionless) of the core material particles.

The spherical equivalent surface area a is a specific surface area per unit mass when the core particles are assumed to be completely smooth spheres, and can be derived as follows.
When the volume average particle diameter of the core particles is d (μm), the surface area S (m ² ) and volume V (m ² ) of one core particle are represented by the following formulas (5) and (6). .
Formula (5): S = 4π × {(d / 2) × 10 ⁻⁶ } ²
Formula (6): V = (4/3) × π × {(d / 2) × 10 ⁻⁶ } ³
When the true specific gravity of the core material particles is ρ (dimensionless), the density of the core material particles is represented by ρ × 10 ⁶ (g / m ³ ), and the mass M (g) of one core material particle is as follows. It is represented by Formula (7).
Formula (7): M = V × ρ × 10 ⁶ = (1/6) πρd ³ × 10 ⁻¹²
Therefore, as described above, since the spherical equivalent specific surface area a is a surface area per unit mass, the above formula (4) is derived as in the following formula (8).
Formula (8): a = S / M = 6 / (d × ρ)

  The volume average particle diameter d of the core particles is measured using a laser diffraction / scattering particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER).

  A method for measuring the true specific gravity ρ of the core particles will be described later.

  The core particles used in the embodiment preferably satisfy the above conditions, but are not particularly limited. Specific examples of the material of the core particles include magnetic metals such as iron, steel, nickel, and cobalt; alloys of these magnetic metals with manganese, chromium, rare earth, and the like; and magnetic oxides such as ferrite and magnetite; Etc. From the viewpoint of using the magnetic brush method, it is desirable that the carrier is a magnetic carrier. Therefore, the material of the core material particles is also desirably a magnetic material. In particular, as the core material particles suitably used in the present embodiment, ferrite particles are preferable because surface uniformity is easy and chargeability is stable.

  The core material particles are formed by granulation and sintering, but are preferably finely pulverized as a pretreatment. The pulverization method is not particularly limited, and pulverization can be performed according to a known pulverization method. Specific examples include a mortar, a ball mill, and a jet mill. Although the final pulverized state in the pretreatment varies depending on the material and the like, the volume average particle size is preferably 2 μm or more and 10 μm or less. If it is less than 2 μm, the desired particle size may not be obtained. If it exceeds 10 μm, the particle size may become too large, or the circularity may become small.

  In addition, the sintering temperature is preferably kept lower than in the conventional case. Specifically, although it varies depending on the material used, 500 ° C. or more and 1200 ° C. or less is preferable, and 600 ° C. or more and 1000 ° C. or less is more preferable. . If the sintering temperature is less than 500 ° C., the magnetic force required for the carrier may not be obtained. If the sintering temperature exceeds 1200 ° C., the crystal growth is fast, the internal structure tends to be nonuniform, and cracks and cracks occur. Easy to enter.

  In order to keep the sintering temperature low, in the sintering process, it is preferable to perform preliminary sintering stepwise. Therefore, it is preferable to increase the time required for the entire sintering.

  The volume average particle size of the core particles is preferably 10 μm or more and 500 μm or less, more preferably 20 μm or more and 150 μm or less, and further preferably 30 μm or more and 100 μm or less. When the volume average particle size of the core material particles is less than 10 μm, when used as a developer for developing an electrostatic image, the adhesion force between the toner and the carrier becomes high, and the toner development amount may decrease. On the other hand, if it exceeds 500 μm, the magnetic brush becomes rough, and it may be difficult to form a fine image.

  As for the magnetic force of the core material particles, the saturation magnetization at 1000 oersted is preferably 50 emu / g or more, and more preferably 60 emu / g or more. If the saturation magnetization is weaker than 50 emu / g, the carrier may be developed on the photoreceptor together with the toner.

  The measurement of magnetic characteristics and the apparatus used will be described later.

The volume electrical resistance (volume resistivity) of the core particles is preferably in the range of 10 ⁵ Ω · cm to 10 ^9.5 Ω · cm, and preferably in the range of 10 ⁷ Ω · cm to 10 ⁹ Ω · cm. It is more preferable that If the volume electric resistance is less than 10 ⁵ Ω · cm, when the toner concentration in the developer decreases due to repeated copying, charges may be injected into the carrier and the carrier itself may be developed. On the other hand, if the volume electric resistance is larger than 10 ^9.5 Ω · cm, the image quality may be adversely affected, such as a prominent edge effect or pseudo contour.

  The volume electric resistance (Ω · cm) of the core particles will be described later. The measurement environment is a temperature of 20 ° C. and a humidity of 50% RH.

<Coating resin layer>
The coating resin layer used for the carrier of the present embodiment is a copolymer obtained by polymerizing a polymerizable monomer represented by the following general formula (I) and a polymerizable monomer represented by the following general formula (II). A polymer (hereinafter sometimes referred to as a specific polycarbonate resin), wherein the copolymer has a copolymerization ratio of 20/80 to 80/20.
The coating resin layer covers the surface of the core material particles described above.

  The copolymerization ratio of the specific polycarbonate resin is preferably 20/80 to 80/20, more preferably 30/70 to 70/30, and particularly preferably 40/60 to 60/40. When the copolymerization ratio is outside the range of 20/80 to 80/20, sufficient flexibility cannot be obtained when the core particles are coated, and the adhesion of the external additive to the carrier is insufficiently suppressed. There is a case. In addition, the said copolymerization ratio means the copolymerization ratio of the polymerizable monomer represented by general formula (I), and the polymerizable monomer represented by general formula (II).

  Further, the copolymerization ratio of the specific polycarbonate resin in the embodiment is more preferably in the following range in relation to the particle size of inorganic particles as external additives in the toner described later.

When the particle size of the inorganic particles is larger, for example, 0.20 μm or more and 0.35 μm or less (preferably 0.25 μm or more and 0.30 μm or less), the copolymerization ratio is preferably 50/50 to 20/80, More preferably, it is 45/55 to 25/75, and particularly preferably 40/60 to 30/70.
By setting the relationship between the particle size of the inorganic particles and the copolymerization ratio as described above, the coating resin layer having the copolymerization ratio in the above range exhibits excellent flexibility. It is possible to suppress the abrasion of the coating resin layer that occurs when it collides with.

When the particle size of the inorganic particles is on the small particle size side, for example, 0.05 μm or more and 0.20 μm or less (preferably 0.10 μm or more and 0.15 μm or less), the copolymerization ratio is preferably 80/20 to 50/50, More preferably, it is 75/25 to 55/45, and particularly preferably 70/30 to 60/40.
By setting the relationship between the particle size of the inorganic particles and the copolymerization ratio as described above, the coating resin layer having the copolymerization ratio in the above range exhibits excellent impact resistance. It is possible to suppress the abrasion of the coating resin layer that occurs when the rubs.

  The molecular weight of the copolymer (specific polycarbonate resin) is preferably in the range of 10,000 to 100,000 in terms of weight average molecular weight. When the molecular weight is less than 10,000, the impact resistance of the resin is impaired. When the molecular weight is greater than 100,000, the viscosity of the resin increases, so that a uniform coated resin layer may not be obtained.

The specific polycarbonate resin used in the present embodiment is synthesized using a known method. Specifically, for example, it can be synthesized by the following two methods. The first method is the so-called solvent method or solution method. By blowing vaporized phosgene into a suspension of an alkaline aqueous solution of a divalent hydroxy compound and an organic solvent (for example, methylene chloride), a high polymerization degree is obtained. This is a method for obtaining a polycarbonate resin. The solvent method has a feature that it can be produced freely even to a very high degree of polymerization, but requires a process of refining and separating a resin dissolved in an organic solvent.
The second method is a transesterification method or a melting method, and is a method in which a polyvalent hydroxy compound and a carbonic acid diester compound are polycondensed in a molten state to obtain a polycarbonate resin. This method has the advantage that the product can be taken out as a uniform melt, but it is difficult to produce a high molecular weight product.

  The copolymer can contain other polymerizable monomer components as long as the effects of the present embodiment are not impaired.

The coating resin layer used in the embodiment can be used with the specific polycarbonate resin alone, but may be a copolymer with other resins. Specific examples of other resins include amino group-containing acrylic polymerizable monomers such as dimethylaminoethyl methacrylate, dimethylamino methacrylate, dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, dimethylacrylamide, isopropylacrylamide, and acryloylmorpholine. Nitrogen-containing acrylic polymerizable monomers including derivatives thereof; other acrylic polymerizable monomers; polymerizable monomers constituting olefin resins such as polyethylene and polypropylene; polystyrene resins, polyvinyl alcohol, polyvinyl butyral , Polymerizable monomers constituting polyvinyl resins and polyvinylidene resins such as polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone; A polymerizable monomer constituting a straight silicone resin comprising a oxane bond or a modified product thereof; a polymerizable monomer constituting a fluororesin such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Body; Polyurethane resin, phenol resin, urea-formaldehyde resin (urea resin), melamine resin, benzoguanamine resin, polymerizable monomer constituting amino resin such as polyamide resin; polymerizable monomer constituting epoxy resin; etc. Examples thereof include homopolymers and copolymers such as polymerizable monomers constituting the known resins. These resins may be used alone or in combination of two or more.
These other resins may be blended with the above copolymer.

  As a polymerization ratio of the copolymer of the specific polycarbonate resin and the other resin in the coating resin layer, the content of the other resin is 0.1 parts by weight or more when the whole copolymer is 100 parts by weight. It is preferably 10.0 parts by weight or less, more preferably 0.1 parts by weight or more and 5.0 parts by weight or less, and particularly preferably 0.1 parts by weight or more and 3.0 parts by weight or less. If the content of the other resin is more than 10.0 parts by weight, the excellent surface wettability, flexibility and impact resistance of the specific polycarbonate resin may not be obtained.

  The coating resin layer is not limited to a single layer, and may have a multilayer structure of two or more layers.

The coating resin layer may contain conductive powder as needed for the purpose of controlling resistance.
Specific examples of the conductive powder include metal particles such as gold, silver and copper; carbon black; ketjen black; acetylene black; semiconductive oxide particles such as titanium oxide and zinc oxide; titanium oxide, zinc oxide and sulfuric acid. And particles having the surface of barium, aluminum borate, potassium titanate powder or the like covered with tin oxide, carbon black, metal, or the like.
These may be used individually by 1 type and may use 2 or more types together.

As the conductive powder, carbon black particles are preferable in terms of good production stability, cost, conductivity and the like.
Although there is no restriction | limiting in particular as a kind of carbon black, The carbon black whose DBP oil absorption is about 50-250 ml / 100g is excellent in manufacturing stability, and preferable.

  The volume average particle diameter of the conductive powder is preferably 0.5 μm or less, more preferably 0.05 μm or more and 0.5 μm or less, and still more preferably 0.05 μm or more and 0.35 μm or less. If the volume average particle diameter is smaller than 0.05 μm, the conductive particles will not be able to obtain the effect of entering the irregularities on the surface of the core particles, and if the volume average particle diameter is larger than 0.5 μm, the conductive powder will fall off the coating resin layer. It may be difficult to obtain a stable chargeability.

  The volume average particle size of the conductive powder is measured using a laser diffraction particle size distribution analyzer (LA-700: manufactured by Horiba, Ltd.).

  As a measurement method, 2 g of a measurement sample was added to a surfactant, preferably 50 ml of a 5% aqueous solution of sodium alkylbenzenesulfonate, and dispersed for 2 minutes with an ultrasonic disperser (1,000 Hz) to prepare a sample. taking measurement.

  The obtained volume average particle diameter for each channel is accumulated from the smaller volume average particle diameter, and the volume average particle diameter is defined as 50%.

The volume electric resistance of the conductive powder is preferably from 10 ¹ Ω · cm to 10 ¹¹ Ω · cm, and more preferably from 10 ³ Ω · cm to 10 ⁹ Ω · cm.
The volume electrical resistance of the conductive powder is measured in the same manner as the volume electrical resistance of the core particles.

  The content of the conductive powder is preferably 1% by volume or more and 50% by volume or less, and more preferably 3% by volume or more and 20% by volume or less with respect to the entire coating resin layer. When the content is more than 20% by volume, the carrier resistance is lowered, and image loss may be caused due to carrier adhesion to the developed image. On the other hand, if the content is less than 1% by volume, the carrier is insulated, and it becomes difficult for the carrier to function as a developing electrode during development, and an edge effect is produced particularly when a black solid image is formed. May be inferior.

  In addition, the coating resin layer may contain other resin particles. Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, a thermosetting resin is preferable from the viewpoint of relatively easily increasing the hardness, and resin particles of a nitrogen-containing resin containing a nitrogen atom are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together.

  The volume average particle diameter of the resin particles is preferably, for example, from 0.1 μm to 2.0 μm, and more preferably from 0.2 μm to 1.0 μm. If the average particle size of the resin particles is less than 0.1 μm, the dispersibility of the resin particles in the coating resin layer may be extremely deteriorated. On the other hand, if the average particle size exceeds 2.0 μm, the resin particles are dispersed from the coating resin layer. Dropout easily occurs and the original effect may not be exhibited.

  The volume average particle diameter of the resin particles can be obtained by performing the same measurement as the volume average particle diameter of the conductive powder.

  The content of the resin particles is preferably 1% by mass or more and 50% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and still more preferably 1% by mass or more and 20% by mass with respect to the entire coating resin layer. It is as follows. When the content of the resin fine particles is less than 1% by mass, the effect of the resin particles may not be exhibited. When the content exceeds 50% by mass, the resin resin is easily detached from the coating resin layer, and stable chargeability cannot be obtained. There is a case.

The method for forming the coating resin layer on the surface of the core particle is not particularly limited. For example, a method using a coating resin layer forming liquid containing conductive powder and the specific polycarbonate resin in a solvent. Is mentioned.
For example, a dipping method in which core material particles are immersed in a coating resin layer forming liquid, a spray method in which a coating resin layer forming liquid is sprayed on the surface of the core material particles, and a coating resin in a state where the core material particles are suspended by flowing air Examples thereof include a kneader coater method in which the solvent is removed by mixing with a layer forming solution. Among these, the kneader coater method is preferable in the present embodiment.

  The solvent used in the coating resin layer forming liquid is not particularly limited as long as it can dissolve only the resin, and can be selected from known solvents. Specific examples include aromatic hydrocarbons such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane;

  When resin particles are dispersed in the coating resin layer, the resin particles are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. However, it is possible to always maintain the same surface formation as when it is not used, and to maintain a good charge imparting ability for the toner over a long period of time.

  In the case where conductive powder is dispersed in the coating resin layer, the conductive powder is uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Even if it is worn, it is possible to always maintain the same surface formation as when not in use, and to prevent carrier deterioration for a long time.

  In the case where resin particles and conductive powder are dispersed in the coating resin layer, the above-described effects can be achieved simultaneously.

  The total content of the coating resin layer in the carrier of the present embodiment is preferably in the range of 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the core particles. Part or less, more preferably 1 part by weight or more and 3 parts by weight or less. If the content of the coating resin layer is less than 0.5 parts by weight, the surface exposure of the core material particles is too much, so that a development electric field may be easily injected. Further, when the content of the coating resin layer is larger than 10 parts by weight, the resin powder released from the coating resin layer increases, and there is a possibility that the carrier resin powder peeled off in the developer from the beginning is contained. is there.

  The coverage of the core particle surface by the coating resin layer is preferably 80% or more, more preferably 85% or more, and the closer to 100%, the more preferable. When the coverage is less than 80%, charge injection into the carrier occurs when it is used for a long period of time, and the carrier in which the charge injection has occurred migrates to the photoconductor, causing white spots on the image. May end up.

  The coverage of the coating resin layer will be described later.

  The average film thickness of each coating resin layer is preferably from 0.1 μm to 10 μm, more preferably from 0.1 μm to 3.0 μm, and even more preferably from 0.1 μm to 1.0 μm. is there. When the average thickness of the coating resin layer is less than 0.1 μm, there may be a decrease in resistance due to peeling of the coating resin layer when used for a long time or it may be difficult to sufficiently control the pulverization of the carrier. On the other hand, when the average film thickness of the coating resin layer exceeds 10 μm, it may take time to reach the saturation charge amount.

The average film thickness (μm) of the coating resin layer is such that the true specific gravity of the core material is ρ (dimensionless), the volume average particle diameter of the core material is d (μm), the average specific gravity of the coating resin layer is ρC, and the core material is 100 weight. When the total content of the coating resin layer with respect to parts is WC (parts by weight), it can be obtained as in the following formula (9).
Formula (9): Average film thickness (μm) = [Amount of coating resin per carrier (including all additives such as conductive powder) / Surface area per carrier] ÷ Average specific gravity of coating resin layer = [4 / 3π · (d / 2) 3 · ρ · WC] / [4π · (d / 2) 2] / ρC
= (1/6) · (d · ρ · WC / ρC)

<Characteristics of carrier>
The weight average particle diameter of the carrier is preferably 15 μm or more and 50 μm or less, more preferably 25 μm or more and 40 μm or less. When the weight average particle diameter of the carrier is smaller than 15 μm, the carrier contamination may be deteriorated. On the other hand, if the weight average particle diameter of the carrier is larger than 50 μm, toner deterioration due to stirring may become remarkable.

  The weight average particle diameter of the carrier is measured using a laser diffraction / scattering type particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER).

  For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size at 50% cumulative is taken as the volume average particle size.

  Further, the shape factor SF1 of the carrier is preferably 100 or more and 145 or less. This is to achieve both high image quality and developer agitation efficiency.

The carrier shape factor SF1 means a value obtained by the following equation (10).
Formula (10): SF1 = 100π × (ML) ² / (4 × A)
Here, ML is the maximum length of the carrier particles, and A is the projected area of the carrier particles. The measuring method will be described later.

The saturation magnetization of the carrier is preferably 40 emu / g or more, and more preferably 50 emu / g or more.
As a device for measuring magnetic properties, a vibrating sample type magnetic measuring device VSMP10-15 (manufactured by Toei Kogyo Co., Ltd.) is used. The measurement sample is packed in a cell having an inner diameter of 7 mm and a height of 5 mm and set in the apparatus. The measurement applies an applied magnetic field and sweeps up to 1000 oersted. Next, the applied magnetic field is decreased to create a hysteresis curve on the recording paper. Saturation magnetization, residual magnetization, and coercive force are obtained from the curve data. In the present embodiment, the saturation magnetization indicates the magnetization measured in a 1000 oersted magnetic field.

The volume electric resistance of the carrier is preferably controlled in the range of 1 × 10 ⁷ Ω · cm to 1 × 10 ¹⁵ Ω · cm, preferably 1 × 10 ⁸ Ω · cm to 1 × 10 ¹⁴ Ω · cm. The range is more preferable, and the range of 1 × 10 ⁸ Ω · cm to 1 × 10 ¹³ Ω · cm is more preferable.
When the volume electrical resistance of the carrier exceeds 1 × 10 ¹⁵ Ω · cm, the resistance becomes high, and it becomes difficult to work as a developing electrode during development. There is. On the other hand, if it is less than 1 × 10 ⁷ Ω · cm, the resistance becomes low, so that when the toner concentration in the developer is lowered, charges are injected from the developing roll into the carrier, and the carrier itself is developed. It may be easier.
The volume electric resistance of the carrier is measured in the same manner as the volume electric resistance of the core particles.

[Toner composition]
The toner used in this exemplary embodiment is not particularly limited as long as it is a colored toner in which inorganic particles are attached to toner particles including at least a colorant and a binder resin, and a known toner can be used.

<Inorganic additive external particles>
The toner used in the present embodiment needs to add inorganic particles to the surface of the toner particles. The volume average particle size of the inorganic particles added to the surface of the toner particles is preferably in the range of 0.05 μm or more and 0.35 μm or less, more preferably in the range of 0.07 μm or more and 0.20 μm or less, and still more preferably. It is the range of 0.09 μm or more and 0.15 μm or less. When the volume average particle diameter of the inorganic particles is smaller than 0.05 μm, the non-electrostatic adhesion with the toner increases and the separation becomes difficult, but the embedding into the toner is likely to occur and There is a tendency for adhesion to the carrier to become stronger. On the other hand, if it is larger than 0.35 μm, the adhesion to the carrier is weakened, but it is easily released from the toner, and the effect as a spacer agent may not be maintained.

  The volume average particle diameter of the inorganic particles is measured using a laser diffraction / scattering particle size distribution measuring apparatus (LA-910: manufactured by Horiba, Ltd.).

Specifically as the inorganic _{particles, SiO 2, TiO 2, Al} 2 O 3, CuO, ZnO, SnO 2, CeO 2, Fe 2 O 3, MgO, BaO, CaO, K 2 O, Na 2 O, ZrO 2 , it can be used _{CaO · SiO 2, K 2 O} · (TiO 2) n, Al 2 O 3 · SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like. Of these, silica fine particles and titania fine particles are particularly preferable.

  It is desirable that the surface of the inorganic particles as the external additive is previously hydrophobized. This hydrophobization treatment improves the powder flowability of the toner, and is effective for the environmental dependency of charging and the resistance to carrier contamination. The hydrophobic treatment can be performed by immersing inorganic particles in the hydrophobic treatment agent, as described above. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together. Of these, silane coupling agents are preferred.

  As the silane coupling agent, for example, any one of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyl Triethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltriethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N- (trimethylsilyl) ) Urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacrylic Xylopyryltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like can be mentioned.

  The amount of the hydrophobizing agent used varies depending on the type of inorganic particles and cannot be defined unconditionally, but is usually in the range of 5 to 50 parts by weight per 100 parts by weight of the inorganic particles.

<Binder resin>
Binder resins include monoolefins such as ethylene, propylene, butylene, and isoprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; methyl acrylate, phenyl acrylate, octyl acrylate, and methacrylic acid. Α-methylene aliphatic monocarboxylic esters such as methyl, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether; vinyl methyl ketone, vinyl hexyl ketone, vinyl Homopolymers or copolymers of vinyl ketones such as isopropenyl ketone; Among these, particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polystyrene, polypropylene, and the like. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin and the like.

  In this embodiment, the glass transition point of the binder resin is measured by using a differential scanning calorimeter (DSC) when the temperature is measured from room temperature to 150 ° C. at a rate of 10 ° C. per minute. The melting peak temperature of the input compensated differential scanning calorimetry shown in JIS K-7121-87.

<Colorant>
The colorant is not particularly limited. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, deyupon oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment blue 15: 1, pigment blue 15: 3, and the like.

<Charge control agent>
Further, the toner can contain a charge control agent as required. At that time, a colorless or light-color charge control agent that does not affect the color tone is preferable, particularly when used for a color toner or the like. As the charge control agent, known ones can be used, but azo metal complexes; salicylic acid or alkyl salicylic acid metal complexes or metal salts; and the like are preferably used.

<Wax>
The toner can also contain other known components such as low molecular weight propylene, low molecular weight polyethylene, and an anti-offset agent such as wax.
Examples of the wax include the following. Paraffin wax and derivatives thereof, montan wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, and the like. Derivatives include oxides, polymers with vinyl polymerizable monomers, and graft modified products. In addition, alcohols, fatty acids, plant waxes, animal waxes, mineral waxes, ester waxes, acid amides, and the like can be used.

<Internal additive inorganic particles>
The toner may contain inorganic oxide particles inside. Examples of the inorganic oxide particles include SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, and ZrO _2. , it can be exemplified _{CaO · SiO 2, K 2 O} · (TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like. Of these, silica particles and titania particles are particularly preferable. The surface of the oxide particles does not necessarily need to be hydrophobized in advance, but may be hydrophobized. When the hydrophobic treatment is performed, even when some of the internal inorganic particles are exposed on the toner surface, it is possible to effectively reduce the environmental dependency of charging and carrier contamination.

  The hydrophobic treatment can be performed by immersing an inorganic oxide in a hydrophobic treatment agent. Although there is no restriction | limiting in particular as a hydrophobization processing agent, For example, a silane coupling agent, a silicone oil, a titanate coupling agent, an aluminum coupling agent etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Of these, silane coupling agents are preferred.

  As the silane coupling agent, for example, any of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltriethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N- ( Trimethylsilyl) urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane , Γ-methacryloxypyrroletrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercapto Examples thereof include propyltrimethoxysilane and γ-chloropropyltrimethoxysilane.

  The amount of the hydrophobizing agent varies depending on the kind of the inorganic oxide particles and cannot be generally defined, but is usually preferably about 5 to 50 parts by weight with respect to 100 parts by weight of the inorganic oxide particles.

<Toner characteristics>
With respect to the particle size distribution of the toner, toner particles having a particle size of 4 μm or less are preferably 6 to 25% by number, more preferably 6 to 16% by number of the total number of toner particles. When the toner particles having a particle size of 4 μm or less are less than 6% by number, there are few particles that contribute to minute dot reproducibility and graininess, and they are selectively consumed because they are effective particle sizes, so repetitive copying In this case, toner having a particle size that hardly contributes to development stays in the developing machine, and the image quality may gradually deteriorate. On the other hand, if it exceeds 25% by number, the fluidity of the toner is deteriorated, so that the developer transportability is lowered, and there is a concern that the developability is adversely affected.

  The toner particles having a particle diameter of 16 μm or more are preferably 1.0% by volume or less. If it exceeds 1.0% by volume, not only will fine line reproducibility and gradation be adversely affected, but also during transfer, coarse toner particles of 16 μm or more will be present in the toner layer, so Since it works to hinder the electroadhesion state, there is a risk of lowering transfer efficiency and eventually image quality.

The particle size distribution of the toner in the embodiment was determined by the following method. For the particle size range (channel) obtained by dividing the measured particle size distribution, draw the volume cumulative distribution from the smaller particle size, define the volume average particle size to be 16% cumulative as D16v, and volume average to be 50% cumulative The particle size is defined as D50v. Furthermore, the volume average particle diameter that is 84% cumulative is defined as D84v. The volume average particle diameter in the embodiment is D50v, and GSDv is calculated by the following equation.
GSDv = (D84v / D16v) ^0.5
The toner particle size distribution (GSDv) in the embodiment is preferably 1.25 or less.
As described above, the carrier of the embodiment is a carrier that suppresses the peeling and scraping of the coating resin layer and has stable charging characteristics. Therefore, the particle size distribution (such as the above range in which the coating resin layer of the carrier is easily peeled and scraped) Even when a toner having a relatively small GSDv) is used, it is possible to suppress peeling and scraping of the coating resin layer, and to form an image having excellent developability and transferability without fogging over a long period of time.

  The volume average particle diameter of the toner is preferably 5 μm or more and 9 μm or less, and in order to reproduce high image quality, it is desirable that the toner satisfies both the above-mentioned preferable range of the particle size distribution. When the volume average particle diameter is less than 5 μm, not only the fluidity of the toner is deteriorated, but also it becomes difficult to give sufficient chargeability from the carrier, so that fogging to the background portion is likely to occur and density reproducibility is liable to be lowered. It may become. If the volume average particle diameter exceeds 9 μm, the above-mentioned carrier characteristics cannot be sufficiently exhibited, and the effect of improving the reproducibility, gradation and graininess of fine dots may be poor.

  Therefore, by having the above-mentioned toner particle size distribution and volume average particle diameter, the image area of photographs, paintings, pamphlets, etc. has a large image area, and even in the repetitive copying of a document with density gradation, it can be used for fine latent image dots. , Faithful reproducibility can be expected.

  The particle size distribution and volume average particle size of the toner will be described later.

  As a method for producing the toner, generally used kneading and pulverizing methods, wet granulation methods, and the like can be used. Here, as the wet granulation method, suspension polymerization method, emulsion polymerization method, emulsion polymerization aggregation method, soap-free emulsion polymerization method, non-aqueous dispersion polymerization method, in-situ polymerization method, interfacial polymerization method, emulsion dispersion granulation Method, agglomeration / unification method and the like can be used.

  In order to produce the toner of the present embodiment by the kneading and pulverization method, the binder resin, and if necessary, a colorant and other additives are sufficiently mixed by a mixer such as a Henschel mixer and a ball mill, The toner is melted and kneaded using a heat kneader such as a kneader or extruder to dissolve the resins together, and the infrared absorber, antioxidant, etc. are dispersed or dissolved, cooled and solidified, and then pulverized and classified. Can be obtained.

When toner particles are produced by a wet granulation method, the shape factor of the toner particles can be arbitrarily changed, and can be produced, for example, in the range of 110 to 145. As described above, the carrier of the embodiment suppresses the peeling and scraping of the coating resin layer, and is a carrier having stable charging characteristics. Therefore, the contact area between the carrier and the toner is small, and the coating resin layer of the carrier is peeled off or scraped. For example, even when a toner having a shape factor of less than 110 or more than 145 is used, peeling and scraping of the coating resin layer is suppressed, and an image having excellent developability and transferability is formed over a long period of time. be able to.
Here, the shape factor of the toner particles is obtained in the same manner as the shape factor SF1 of the carrier.

  In the developer according to the exemplary embodiment, the toner / carrier mixing weight ratio is preferably 0.01 to 0.3, more preferably 0.03 to 0.2.

  The developer of the present embodiment can be applied not only as a developer stored in advance in a developing means (developer storage container) but also as a supply developer used in, for example, a trickle development system. it can.

[Electrophotographic developer cartridge, image forming apparatus, process cartridge]
Next, the electrophotographic developer cartridge of the embodiment (hereinafter sometimes abbreviated as “cartridge”) will be described. The cartridge according to the embodiment is detachable from the image forming apparatus, and at least for developing the electrostatic latent image formed on the surface of the electrostatic latent image holding member to supply to a developing unit that forms a toner image. A developer is accommodated, and the developer is the developer of the embodiment described above.

  Accordingly, in the image forming apparatus having a configuration in which the cartridge can be attached and detached, by using the cartridge of the embodiment in which the developer of the embodiment is housed, the environmental dependency such as temperature and humidity is small, and the coating resin The layer is difficult to peel off, and image formation can be performed stably over a long period of time.

  Here, the cartridge of the embodiment may be a cartridge that stores the developer of the embodiment, particularly when used in an image forming apparatus of a trickle developing system, or a cartridge that stores toner alone and the cartridge of the embodiment. It may be a separate body from the cartridge that houses the carrier alone.

  The image forming apparatus according to the embodiment includes an electrostatic latent image holding member, an electrostatic latent image forming unit that forms an electrostatic latent image on the surface of the electrostatic latent image holding member, and developing the electrostatic latent image with a developer. Development means for forming a toner image, transfer means for transferring the toner image to a recording medium, and fixing means for fixing the toner image on the recording medium. It is a photographic developer.

  Therefore, by using the image forming apparatus of the embodiment using the developer of the embodiment, the environmental dependency such as temperature and humidity is small, and the coating resin layer is hardly peeled off, and the image is stably formed over a long period of time. Formation can be performed.

  The image forming apparatus according to the embodiment includes at least the electrostatic latent image holding member, the electrostatic latent image forming unit, the developing unit, the transfer unit, and the fixing unit as described above. Although there is no particular limitation, other cleaning means, static elimination means, and the like may be included as necessary.

  The developing means is housed in the developer containing container for containing the developer of the embodiment, the developer supplying means for supplying the developer to the developer containing container, and the developer containing container. A configuration including a developer discharging means for discharging at least a part of the developer, that is, a trickle developing method may be employed.

  Here, the developer (supplying developer) to be supplied to the developer storage container preferably has a toner / carrier mixing weight ratio of toner weight / carrier weight ≧ 2, more preferably the weight ratio is toner. Weight / carrier weight ≧ 3, more preferably toner weight / carrier weight ≧ 5.

  When such a trickle development method is used, if a resin-coated carrier from which the coating resin layer is easy to peel off is used, not only does the coating resin layer peel from the developer originally in the developer container, but also from the developer supply means. The coating resin layer in the developer that is supplied to the developer container as needed is also peeled off, and the influence of the carrier resin peeling powder is greater than when the trickle developing method is not used.

  However, if the image forming apparatus of the embodiment using the developer of the embodiment is used, the resin coating layer in the developer of the embodiment is difficult to peel off, and the above-described problem is hardly caused even when the trickle development method is used. Therefore, it is possible to stably form an image over a long period of time while maintaining charging characteristics.

  The process cartridge according to the embodiment stores the developer according to the embodiment, is detachable from the image forming apparatus, includes a developing unit, and is selected from an electrostatic latent image holding member, a charging unit, and a cleaning unit. It is characterized by providing at least one kind. In addition, the process cartridge according to the embodiment may include other members such as a static eliminating unit as necessary.

  Therefore, in the image forming apparatus having a configuration in which the process cartridge can be attached and detached, by using the process cartridge according to the embodiment, the coating resin layer is hardly peeled off while maintaining the charging characteristics, and the image can be stably formed over a long period of time. Formation can be performed.

  Hereinafter, an electrophotographic developer cartridge, an image forming apparatus, and a process cartridge according to an embodiment will be specifically described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment (first embodiment) of an image forming apparatus. The image forming apparatus illustrated in FIG. 1 includes the cartridge according to the embodiment.

An image forming apparatus 10 shown in FIG. 1 includes an electrostatic latent image holding body 12, a charging unit 14, an electrostatic latent image forming unit 16, a developing unit 18, a transfer unit 20, a cleaning unit 22, a neutralizing unit 24, a fixing unit 26, A cartridge 28 is provided.
The developer stored in the developing unit 18 and the cartridge 28 is the developer of the embodiment.

  For convenience, FIG. 1 illustrates only a configuration including the developing unit 18 and the cartridge 28 each containing the developer according to the embodiment. However, for example, in the case of a color image forming apparatus, the image forming apparatus includes It is also possible to adopt a configuration including a corresponding number of developing means 18 and cartridges 28.

  The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which a cartridge 28 can be attached and detached. The cartridge 28 is connected to the developing means 18 through a developer supply pipe 30. Therefore, when image formation is performed, the developer of the embodiment accommodated in the cartridge 28 is supplied to the developing means 18 through the developer supply rod 30 so that the development of the embodiment can be performed over a long period of time. An image using the agent can be formed. Further, when the amount of developer stored in the cartridge 28 is reduced, the cartridge 28 can be replaced.

  Around the electrostatic latent image holding body 12, a charging means 14 for uniformly charging the surface of the electrostatic latent image holding body 12 in order along the rotation direction (arrow A direction) of the electrostatic latent image holding body 12, an image An electrostatic latent image forming unit 16 that forms an electrostatic latent image on the surface of the electrostatic latent image holding body 12 according to information, a developing unit 18 that supplies the developer of the embodiment to the formed electrostatic latent image, The drum-shaped transfer means 20 that contacts the surface of the electrostatic latent image holding body 12 and can be driven to rotate in the direction of arrow B as the electrostatic latent image holding body 12 rotates in the direction of arrow A, and the electrostatic latent image holding body 12. A cleaning device 22 that abuts on the surface, and a static elimination means 24 that neutralizes the surface of the electrostatic latent image holding body 12 are disposed.

  A recording medium 50 transported in the direction of arrow C by a transport unit (not shown) from the opposite side to the direction of arrow C can be inserted between the electrostatic latent image holding body 12 and the transfer unit 20. A fixing unit 26 having a built-in heating source (not shown) is arranged on the electrostatic latent image holding body 12 in the direction of arrow C. The fixing unit 26 is provided with a pressure contact portion 32. Further, the recording medium 50 that has passed between the electrostatic latent image holding body 12 and the transfer means 20 can be inserted through the pressure contact portion 32 in the direction of arrow C.

As the electrostatic latent image holding member 12, for example, a photosensitive member or a dielectric recording member can be used.
As the photoreceptor, for example, a photoreceptor having a single layer structure or a photoreceptor having a multilayer structure can be used. As the material of the photoconductor, an inorganic photoconductor such as selenium or amorphous silicon, an organic photoconductor, or the like can be considered.

  Examples of the charging means 14 include a contact charging device using a conductive or semiconductive roller, brush, film, rubber blade, etc., a non-contact type charging device such as corotron charging or scorotron charging using corona discharge, etc. Any known means can be used.

As the electrostatic latent image forming means 16, in addition to the exposure means, any conventionally known means capable of forming a signal capable of forming a toner image at a desired position on the surface of the recording medium can be used. .
As the exposure means, for example, a conventionally known exposure means such as a combination of a semiconductor laser and a scanning device, a laser scanning writing device comprising an optical system, or an LED head can be used. In order to realize a preferable mode of producing a uniform and high-resolution exposure image, it is preferable to use a laser scanning writing device or an LED head.

  Specifically, as the transfer unit 20, for example, a conductive or semiconductive roller, brush, film, rubber blade, or the like to which a voltage is applied is used, and the electrostatic latent image holding member 12 and the recording medium 50 are used. A charged toner particle is formed by corona charging the back surface of the recording medium 50 with a means for transferring a toner image composed of charged toner particles, a corotron charger using a corona discharge, or a scorotron charger. Conventionally known means such as a means for transferring a toner image comprising the above can be used.

  A secondary transfer unit can also be used as the transfer unit 20. That is, although not shown, the secondary transfer unit is a unit that transfers the toner image to the intermediate transfer member and then secondary-transfers the toner image from the intermediate transfer member to the recording medium 50.

  Examples of the cleaning unit 22 include a cleaning blade and a cleaning brush.

  Examples of the static eliminating unit 24 include a tungsten lamp and an LED.

As the fixing unit 26, for example, a heat fixing unit that fixes a toner image by heating and pressing such as a heating roll and a pressure roll, or a light fixing that heats and fixes a toner image by light irradiation with a xenon flash lamp or the like. Can be used.
The material forming the roll surface such as a heating roll or a pressure roll is preferably, for example, a material excellent in releasability with respect to the toner, silicon rubber, fluorine resin, or the like for the purpose of preventing the toner from adhering. At this time, it is desirable not to apply a releasable liquid such as silicone oil to both sides of the roll. The releasable liquid is effective for widening the fixing latitude, but since it is transferred to the recording medium to be fixed, stickiness is generated on the printed matter on which the image is formed, and the tape cannot be attached or the character is printed by magic. May cause problems such as being unable to write. This problem becomes more prominent when a film such as OHP is used as the recording medium. In addition, since it is difficult for the releasable liquid to make the surface of the fixed image smooth, the image transparency, which is particularly important when an OHP film is used as a recording medium, may be a factor that decreases. However, when the toner contains a wax (offset preventing agent), it exhibits a sufficient fixing latitude, so that a releasable liquid such as silicone oil applied to the fixing roll is not necessary.

  The recording medium 50 is not particularly limited, and conventionally known media such as plain paper and glossy paper can be used. A recording medium having a base material and an image receiving layer formed on the base material can also be used.

  Next, image formation using the image forming apparatus 10 will be described. First, as the electrostatic latent image holding body 12 rotates in the direction of arrow A, the surface of the electrostatic latent image holding body 12 is charged by the charging unit 14, and the electrostatic latent image holding body 12 surface is charged with the electrostatic latent image. An electrostatic latent image corresponding to the image information is formed by the image forming means 16, and the developing means 18 is formed on the surface of the electrostatic latent image holding body 12 on which the electrostatic latent image is formed according to the color information of the electrostatic latent image. A toner image is formed by supplying the developer of the embodiment.

  Next, the toner image formed on the surface of the electrostatic latent image holding body 12 is brought into contact with the electrostatic latent image holding body 12 and the transfer unit 20 as the electrostatic latent image holding body 12 rotates in the arrow A direction. Move to the department. At this time, the recording medium 50 is inserted through the contact portion in the direction of arrow C by a paper conveyance roll (not shown), and the electrostatic latent image is transferred by the voltage applied between the electrostatic latent image holder 12 and the transfer means 20. The toner image formed on the surface of the image carrier 12 is transferred to the surface of the recording medium 50 at the contact portion.

  The toner remaining on the surface of the electrostatic latent image holding body 12 after the toner image is transferred to the transfer unit 20 is removed by the cleaning blade of the cleaning unit 22 and the charge is removed by the charge removing unit 24.

  The recording medium 50 having the toner image transferred onto the surface in this way is conveyed to the pressure contact portion 32 of the fixing unit 26 and passes through the pressure contact portion 32 to be pressed by a built-in heating source (not shown). The surface of the section 32 is heated by the heated fixing means 26. At this time, an image is formed by fixing the toner image on the surface of the recording medium 50.

  FIG. 2 is a cross-sectional view schematically showing a basic configuration of another preferred embodiment (second embodiment) of the image forming apparatus. In the image forming apparatus shown in FIG. 2, the developer (supplying developer) according to the embodiment is appropriately supplied to the developer storage container in the developing means by the developer supply means, and is stored in the developer storage container. The trickle developing method is adopted in which at least a part of the developer is appropriately discharged by the developer discharging means.

  As shown in FIG. 2, the image forming apparatus 100 according to the embodiment includes an electrostatic latent image holding body 110 that rotates in a clockwise direction, and an electrostatic latent image holding body 110 that is positioned above the electrostatic latent image holding body 110 as shown by an arrow a. A charging unit 120 which is provided relative to the electrostatic latent image holding body 110 and which negatively charges the surface of the electrostatic latent image holding body 110; and a surface of the electrostatic latent image holding body 110 charged by the charging means 120. An electrostatic latent image forming unit 130 for writing an image to be formed with a developer (toner) to form an electrostatic latent image; and an electrostatic latent image forming unit provided on the downstream side of the electrostatic latent image forming unit 130. A developing unit 140 that forms a toner image on the surface of the electrostatic latent image holding member 110 by attaching toner to the electrostatic latent image formed by the unit 130, and an arrow b while contacting the electrostatic latent image holding member 110. The surface of the electrostatic latent image holding body 110 while traveling in the direction shown The endless belt-shaped intermediate transfer belt 150 that transfers the formed toner image and the surface of the electrostatic latent image holding body 110 after the toner image is transferred to the intermediate transfer belt 150 are neutralized to leave a transfer residue remaining on the surface. A neutralization unit 160 that facilitates removal of toner and a cleaning unit 170 that cleans the surface of the electrostatic latent image holding member 110 to remove the transfer residual toner are provided.

  The charging unit 120, the electrostatic latent image forming unit 130, the developing unit 140, the intermediate transfer belt 150, the neutralizing unit 160, and the cleaning unit 170 are arranged in a clockwise direction on the circumference surrounding the electrostatic latent image holding body 110. It is installed.

  The intermediate transfer belt 150 is tensioned and held from the inside by the stretching rollers 150A and 150B, the backup roller 150C, and the driving roller 150D, and is driven in the direction of the arrow b as the driving roller 150D rotates. At a position opposite to the electrostatic latent image holder 110 inside the intermediate transfer belt 150, the intermediate transfer belt 150 is positively charged, and the toner on the electrostatic latent image holder 110 is placed on the outer surface of the intermediate transfer belt 150. A primary transfer roller 151 that adsorbs the toner is provided. On the outer side below the intermediate transfer belt 150, the recording medium P is positively charged and pressed against the intermediate transfer belt 150, thereby transferring the toner image formed on the intermediate transfer belt 150 onto the recording medium P. A transfer roller 152 is provided to face the backup roller 150C.

  Below the intermediate transfer belt 150, a recording medium supply device 153 that supplies the recording medium P to the secondary transfer roller 152 and a recording medium P on which a toner image is formed on the secondary transfer roller 152 are conveyed. Fixing means 180 for fixing the toner image is provided.

  The recording medium supply device 153 includes a pair of conveying rollers 153A and a guide slope 153B that guides the recording medium P conveyed by the conveying rollers 153A toward the secondary transfer roller 152. On the other hand, the fixing unit 180 includes a fixing roller 181 that is a pair of heat rollers for fixing the toner image by heating and pressing the recording medium P on which the toner image has been transferred by the secondary transfer roller 152, and fixing. A conveyance conveyor 182 that conveys the recording medium P toward the roller 181.

  The recording medium P is conveyed in the direction indicated by the arrow c by the recording medium supply device 153, the secondary transfer roller 152, and the fixing unit 180.

  In the vicinity of the intermediate transfer belt 150, an intermediate transfer body cleaning unit 154 having a cleaning blade for removing toner remaining on the intermediate transfer belt 150 after the toner image is transferred to the recording medium P by the secondary transfer roller 152 is provided. It has been.

  Hereinafter, the developing unit 140 will be described in detail. The developing unit 140 is disposed in the developing region so as to face the electrostatic latent image holding member 110. For example, the developing unit 140 includes two-component developing including a toner charged to a negative (−) polarity and a carrier charged to a positive (+) polarity. A developer storage container 141 for storing the developer. The developer container 141 includes a developer container main body 141A and a developer container cover 141B that closes the upper end of the developer container main body 141A.

  The developer container main body 141A has a developing roll chamber 142A for storing the developing roll 142 therein, and is adjacent to the first stirring chamber 143A and the first stirring chamber 143A adjacent to the developing roll chamber 142A. 144A of 2nd stirring chambers. Further, a layer thickness regulating member 145 is provided in the developing roll chamber 142A for regulating the layer thickness of the developer on the surface of the developing roll 142 when the developer containing container cover 141B is attached to the developer containing container main body 141A. It has been.

  The first stirring chamber 143A and the second stirring chamber 144A are partitioned by a partition wall 141C. Although not shown, the first stirring chamber 143A and the second stirring chamber 144A are arranged in the longitudinal direction of the partition wall 141C (developing device). (Longitudinal direction) Communication portions are provided at both ends to communicate with each other, and the first stirring chamber 143A and the second stirring chamber 144A constitute a circulation stirring chamber (143A + 144A).

  The developing roll 142 is disposed in the developing roll chamber 142A so as to face the electrostatic latent image holding body 110. Although not shown, the developing roll 142 is provided with a sleeve outside a magnetic roll (fixed magnet) having magnetism. The developer in the first stirring chamber 143A is adsorbed on the surface of the developing roll 142 by the magnetic force of the magnetic roll and is transported to the developing area. Further, the roll axis of the developing roll 142 is rotatably supported by the developer container main body 141A. Here, the developing roll 142 and the electrostatic latent image holding body 110 rotate in the opposite directions, and the developer adsorbed on the surface of the developing roll 142 at the facing portion advances by the electrostatic latent image holding body 110. The sheet is conveyed to the development area from the same direction as the direction.

  A bias power supply (not shown) is connected to the sleeve of the developing roll 142 so that a predetermined developing bias is applied (in this embodiment, an alternating electric field is applied to the developing region. , Applying a bias in which the AC component (AC) is superimposed on the DC component (DC)).

  The first stirring chamber 143A and the second stirring chamber 144A are provided with a first stirring member 143 (stirring / conveying member) and a second stirring member 144 (stirring / conveying member) that transport the developer while stirring. The first agitating member 143 includes a first rotating shaft extending in the axial direction of the developing roll 142, and an agitating / conveying blade (protrusion) fixed in a spiral manner on the outer periphery of the rotating shaft. Similarly, the second stirring member 144 includes a second rotating shaft and a stirring conveyance blade (protrusion). The stirring member is rotatably supported by the developer container main body 141A. The first stirring member 143 and the second stirring member 144 are arranged such that the developer in the first stirring chamber 143A and the second stirring chamber 144A is conveyed in the opposite directions by rotation thereof. .

  One end of a developer supply unit 146 for appropriately supplying a supply developer including supply toner and a supply carrier to the second agitation chamber 144A is connected to one end side in the longitudinal direction of the second agitation chamber 144A. A developer cartridge 147 containing a supply developer is connected to the other end of the developer supply means 146. One end of the second stirring chamber 144A in the longitudinal direction is also connected to one end of a developer discharging means 148 for appropriately discharging the stored developer, and the other end of the developer discharging means 148 is connected to the other end of the developer discharging means 148. Although not shown, it is connected to a developer recovery container for recovering the discharged developer.

  As described above, the developing unit 140 appropriately supplies the developer for supply from the developer cartridge 147 through the developer supplying unit 146 to the developing unit 140 (second stirring chamber 144A), and the old developer is supplied to the developer discharging unit. A so-called trickle development system that appropriately discharges from 148 (to prevent a decrease in developer charging performance and to extend the developer replacement interval, supply developer (trickle developer) is gradually supplied into the developing device. On the other hand, it is a developing system in which development is performed while discharging an excess of the deteriorated developer (including many deteriorated carriers).

  In this embodiment, the configuration using the developer cartridge 147 that stores the supply developer according to the embodiment has been described as an example. However, the developer cartridge 147 includes a cartridge that stores the supply toner alone. The cartridge for separately storing the supply carrier according to the embodiment may be separated.

  Next, the cleaning unit 170 will be described in detail. The cleaning unit 170 includes a housing 171 and a cleaning blade 172 disposed so as to protrude from the housing 171. The cleaning blade 172 is a plate-like member extending in the extending direction of the rotation axis of the electrostatic latent image holding body 110, and is rotated in the rotation direction (arrow) from the transfer position by the primary transfer roller 151 in the electrostatic latent image holding body 110. a direction) A tip end portion (hereinafter referred to as an edge portion) is provided in pressure contact with the downstream side and the downstream side in the rotational direction from the position where the charge is removed by the charge removal means 160.

  The cleaning blade 172 is held on the electrostatic latent image holding body 110 without being transferred to the recording medium P by the primary transfer roller 151 by rotating the electrostatic latent image holding body 110 in a predetermined direction (direction of arrow a). Foreign matter such as untransferred residual toner and paper dust of the recording medium P is dammed and removed from the electrostatic latent image holding member 110.

  A transport member 173 is disposed at the bottom of the housing 171, and toner particles (developer) removed by the cleaning blade 172 are developed on the downstream side in the transport direction of the transport member 173 in the housing 171. One end of a supply conveying means 174 for supplying to is connected. The other end of the supply / conveyance unit 174 is connected to join the developer supply unit 146.

  As described above, the cleaning unit 170 transports the untransferred residual toner particles to the developing unit 140 (second stirring chamber 144A) through the supply transport unit 174 in accordance with the rotation of the transport member 173 provided at the bottom of the housing 171. Toner reclaim is employed in which the developer (toner) contained therein is stirred and conveyed for reuse.

  FIG. 3 is a cross-sectional view schematically showing a basic configuration of another preferred embodiment (third embodiment) of the image forming apparatus. The image forming apparatus shown in FIG. 3 includes the process cartridge according to the embodiment.

  An image forming apparatus 200 shown in FIG. 3 includes a process cartridge 210 detachably disposed in an image forming apparatus main body (not shown), an electrostatic latent image forming unit 216, a transfer unit 220, and a fixing unit 226. It has.

  The process cartridge 210 has an electrostatic latent image holding body 212 in a casing 211 provided with an opening 211A for forming an electrostatic latent image, and a charging unit 214, a developing unit 218, and a cleaning unit 222 around the electrostatic latent image holding member 212. These are combined and integrated by mounting rails (not shown). Note that the process cartridge 210 is not limited to this, and it is only necessary to include the developing unit 218 and at least one selected from the group consisting of the electrostatic latent image holding member 212, the charging unit 214, and the cleaning unit 222.

  On the other hand, the electrostatic latent image forming unit 216 is disposed at a position where an electrostatic latent image can be formed on the electrostatic latent image holding body 212 from the opening 211A of the casing 211 of the process cartridge 210. The transfer unit 220 is disposed at a position facing the electrostatic latent image holder 212.

  The individual details of the electrostatic latent image holding member 212, the charging unit 214, the electrostatic latent image forming unit 216, the developing unit 218, the transfer unit 220, the cleaning unit 222, the fixing unit 226, and the recording medium 250 are illustrated in FIG. The same as the electrostatic latent image holding body 12, the charging unit 14, the electrostatic latent image forming unit 16, the developing unit 18, the transfer unit 20, the cleaning unit 22, the fixing unit 26, and the recording medium 50 in the image forming apparatus 10 of FIG. .

  The image formation using the image forming apparatus 200 of FIG. 3 is the same as the image formation using the image forming apparatus 10 of FIG.

  Hereinafter, the present embodiment will be described in detail with reference to examples. However, the present embodiment is not limited only to the following examples.

[Measuring method]
<Measurement method of BET specific surface area>
Using a BET specific surface area meter (SA3100, manufactured by Beckman Coulter, Inc.) as a measuring device, 0.1 g of a porous silicon nitride fine powder as a measurement sample is precisely weighed and placed in a sample tube, and then degassed. The numerical value obtained by the point method automatic measurement is defined as the BET specific surface area A of the core material.

<Method for measuring volume average particle diameter of core particles>
The volume average particle diameter of the core material particles was measured using the laser diffraction / scattering particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER). For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution was subtracted from the small particle size side, and the particle size at 50% cumulative was taken as the volume average particle size.

<Measurement method of true specific gravity of core particles>
Further, the true specific gravity of the core particles was measured using a Lechatelier specific gravity bottle in accordance with JIS-K-0061 5-2-1. The operation was as follows.
(1) About 250 ml of ethyl alcohol is put into a Lechatelier specific gravity bottle and adjusted so that the meniscus is at the position of the scale.
(2) The specific gravity bottle is immersed in a constant temperature water bath, and when the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read with the scale of the specific gravity bottle. (Accuracy 0.025ml)
(3) About 100 g of a sample is weighed and its mass is defined as W (g).
(4) Put the weighed sample in a specific gravity bottle to remove bubbles.
(5) The specific gravity bottle is immersed in a constant temperature water bath, and when the liquid temperature becomes 20.0 ± 0.2 ° C., the position of the meniscus is accurately read with the scale of the specific gravity bottle. (Accuracy 0.025ml)
(6) The true specific gravity is calculated by the following formula.
D = W / (L2-L1)
ρ = D / 0.9982
In the formula, D is the density of the sample (20 ° C.) (g / cm ³ ), ρ is the true specific gravity of the sample (20 ° C.), W is the apparent mass (g) of the sample, and L1 is before the sample is placed in the specific gravity bottle. Meniscus reading (20 ° C.) (ml), L2 is the meniscus reading (20 ° C.) (ml) after the sample is placed in the density bottle, 0.9982 is the density of water at 20 ° C. (g / cm ³ ) It is.

<Method for measuring magnetic properties>
As a device for measuring magnetic properties, a vibration sample type magnetic measuring device VSMP10-15 (manufactured by Toei Industry Co., Ltd.) was used. The measurement sample was packed in a cell having an inner diameter of 7 mm and a height of 5 mm and set in the apparatus. In the measurement, an applied magnetic field is applied, and after sweeping up to 3000 oersted, the applied magnetic field is decreased to create a hysteresis curve on the recording paper. Saturation magnetization, residual magnetization, and coercive force are obtained from the curve data. In the present embodiment, the saturation magnetization is a magnetization measured in a 1000 oersted magnetic field.

<Measurement method of volumetric electric resistance of core particle, conductive powder, carrier>
The volume electric resistance (Ω · cm) of the core material particles, conductive powder, and carrier is measured as follows. The measurement environment was a temperature of 20 ° C. and a humidity of 50% RH.
On the surface of a circular jig provided with a 20 cm ² electrode plate, the object to be measured was placed flat to a thickness of about 1 to 3 mm to form a layer. A 20 cm ² electrode plate similar to that described above is placed thereon and the layer is sandwiched. In order to eliminate gaps between objects to be measured, the thickness (cm) of the layer was measured after a load of 4 kg was applied on the electrode plate placed on the layer. Both electrodes above and below the layer are connected to an electrometer and a high voltage power generator. A high voltage was applied to both electrodes so that the electric field was 10 ^3.8 V / cm, and the current value (A) flowing at this time was read to calculate the volume electric resistance (Ω · cm) of the measurement object. The calculation formula of the volume electrical resistance (Ω · cm) of the measurement object is as shown in the following formula.
Formula: R = E × 20 / (I−I ₀ ) / L

In the above formula, R is the volume electric resistance (Ω · cm) of the measurement object, E is the applied voltage (V), I is the current value (A), I ₀ is the current value (A) at the applied voltage of 0 V, and L is Each layer thickness (cm) is expressed. A coefficient of 20 represents the area (cm ² ) of the electrode plate.

<Measurement method of volume average particle diameter in conductive powder and resin particles>
The volume average particle diameters of the conductive powder and the resin particles were measured using a laser diffraction particle size distribution analyzer (LA-700: manufactured by Horiba, Ltd.).

  As a measuring method, the sample in the state of dispersion was adjusted so as to have a solid content of about 2 g, and ion exchange water was added thereto to make about 40 ml. This was put into the cell until an appropriate concentration was reached, waited for 2 minutes, and measured when the concentration in the cell became almost stable.

  The volume average particle diameter of each obtained channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

<Measurement method of coverage>
The coverage of the coating resin layer was determined by XPS measurement. JPS 80 manufactured by JEOL Ltd. is used as the XPS measuring apparatus, and the measurement is performed by using MgKα ray as the X-ray source, setting the acceleration voltage to 10 kV and the emission current to 20 mV, and constituting the coating resin layer. Element (usually carbon) and main elements constituting the core material (for example, iron and oxygen when the core material is an iron oxide-based material such as magnetite) were measured (hereinafter, the core material is iron oxide-based). It will be explained assuming the case). Here, the C1s spectrum was measured for carbon, the Fe2p3 / 2 spectrum was measured for iron, and the O1s spectrum was measured for oxygen.

Based on the spectrum of each of these elements, the number of carbon, oxygen, and iron elements (A _C + A _O + A _Fe ) is obtained, and the following formula (11) is obtained from the obtained carbon, oxygen, and iron element number ratio. Based on this, the iron content rate of the core material alone and after the core material was coated with the coating resin layer (carrier) was determined, and then the coverage rate was determined by the following formula (12).
Formula (11): Iron content rate (atomic%) = A _Fe / (A _C + A _O + A _Fe ) × 100
Formula (12): Coverage rate (%) = {1− (iron content rate of carrier) / (iron content rate of core material alone)} × 100

  When a material other than iron oxide is used as the core particle, the spectrum of the metal element that constitutes the core material in addition to oxygen is measured, and according to the above formulas (11) and (12). The coverage can be obtained by performing the same calculation.

The average film thickness (μm) of the coating resin layer is such that the true specific gravity of the core material particles is ρ (dimensionless), the volume average particle diameter of the core material particles is d (μm), the average specific gravity of the coating resin layer is ρ _C , the core When the total content of the coating resin layer with respect to 100 parts by weight of the material particles is W _C (parts by weight), it can be obtained as in the following formula (9).
Formula (9): Average film thickness (μm) = [Amount of coating resin per carrier (including all additives such as conductive powder) / Surface area per carrier] ÷ Average specific gravity of coating resin layer = [4 / 3π · (d / 2) ³ · ρ · W _C ] / [4π · (d / 2) ² ] ÷ ρ _C
= (1/6) · (d · ρ · W _C / ρ _C )

<Measurement method of volume average particle diameter of toner>
The volume average particle diameter of the toner is measured using a Coulter Multisizer II (manufactured by Beckman Coulter, Inc.). As the electrolytic solution, ISOTON-II (manufactured by Beckman Coulter) is used.

  As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant, and this is added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute. Using the Coulter Multisizer II type, an aperture having an aperture diameter of 100 μm is used, and the particle diameter is 2.0 to 60 μm. The particle size distribution of the particles in the range is measured. The number of particles to be measured is 50,000.

For the divided particle size range (channel), draw the cumulative distribution from the smaller diameter side in terms of weight or volume, and define the 50% cumulative particle size as the heavy average particle size or volume average particle size, respectively. To do.
GSDv = (D84v / D16v) ^0.5

<Measuring method of weight average particle diameter of carrier>
Specifically, the weight average particle diameter of the carrier can be indicated by accumulating the residual amount on the sieve when the carrier 100 g is passed through several kinds of sieves having different openings. In the present invention, a sieve having an opening that gradually spreads from 10 μm to 100 μm, a small sieve having openings are arranged from the bottom, a sieve having an opening of 100 μm is placed on top, and then a carrier is placed on the sieve having an opening of 100 μm. After placing and applying sonic vibration, the weight of the carrier remaining on each sieve was measured. When the carrier passing weight is 100, the particle diameter at which the particle diameter is 50% from the bottom is D50, and this is the weight average particle diameter of the carrier. D50 does not always have a weight of just 50% due to the opening of the sieve. In that case, D50 was calculated by the following calculation.
1. A μm is the sieve containing the 50% mesh, and a is the cumulative carrier amount counted from the bottom including the carrier remaining on the sieve.
2. Let B be the sieve that is one lower than the sieve containing the 50% mesh, and b be the cumulative amount of carrier counted from the bottom including the carrier remaining on the sieve.
3. D50 = {(50−b) / (a−b)} × (A−B) + B
According to the above method, D50 can be obtained even if the mesh opening intervals are different.
As a more specific example, if the opening is 45 μm, the accumulation is 55%, the opening is 31 μm, and the accumulation is 30%,
D50 = {(50-30) / (55-30)} × (45-31) + 31 = 42.2 μm
It becomes.
In addition, the sieve used by this invention and its opening are as follows. HD10 (10 μm), HC-15 (15 μm), P-25 (25 μm), NY31-HC (31 μm), DIN120-45 (45 μm), NY50-HD (50 μm), HC-60 (60 μm), DIN80-75 (75 μm), NY100-HC (100 μm) (both manufactured by Sanjiro Tanaka Shoten)

<How to find the shape factor>
The shape factor SF1 is obtained by the following equation (10).
Formula (10): SF1 = 100π × (ML) ² / (4 × A)
Here, ML is the maximum length of the particle, and A is the projected area of the particle. The maximum length and projected area of the particles can be obtained by observing the particles sampled on the slide glass with an optical microscope, importing them into an image analyzer (LUZEX III, manufactured by NIRECO) through a video camera, and performing image analysis. it can. The number of samplings at this time is 100 or more, and the shape factor shown in Expression (10) is obtained using the average value.

<Measurement method of glass transition point of resin>
The glass transition point (Tg) of the resin is measured using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC-50) under a temperature rising rate of 3 ° C./min. The temperature at the point of intersection of the extension line and the glass transition point.

<Method for measuring volume average particle diameter of external additive>
The volume average particle diameter of the inorganic particles is measured using a laser diffraction / scattering particle size distribution measuring apparatus (LA-910: manufactured by Horiba, Ltd.).

[Manufacture of core particles A to E]
<Manufacture of core particle A>
The production of the core material particles A was performed as follows.
Fe ₂ O ₃ 72 parts by weight MnO ₂ 20 parts by weight Mg (OH) ₂ 7 parts by weight are mixed, pulverized in a wet ball mill for 28 hours, granulated and dried by a spray dryer, and then at 830 ° C. using a rotary kiln. 7 hours pre-baking 1 was performed. The pre-fired product thus obtained was pulverized for 2 hours with a wet ball mill to a volume average particle size of 2.0 μm, further granulated and dried with a spray dryer, and then at 920 ° C. for 6 hours using a rotary kiln. The preliminary firing 2 was performed. The two calcined products thus obtained were pulverized with a wet ball mill for 5 hours to a volume average particle size of 5.5 μm, further granulated and dried with a spray dryer, and then at a temperature of 910 ° C. using an electric furnace. The main baking was performed for 12 hours. Through the pulverization step and the classification step, core material particles A having a volume average particle size of 34.0 μm were prepared. The BET specific surface area was 0.196.
The properties of the obtained core particle A are as shown in Table 1.

<Manufacture of core particle B>
The production of the core particle B was performed as follows.
Fe ₂ O ₃ 72 parts by weight MnO ₂ 20 parts by weight Mg (OH) ₂ 7 parts by weight are mixed, pulverized in a wet ball mill for 28 hours, granulated and dried by a spray dryer, and then at 830 ° C. using a rotary kiln. 7 hours pre-baking 1 was performed. The pre-fired product thus obtained was pulverized for 2 hours with a wet ball mill to a volume average particle size of 2.0 μm, further granulated and dried with a spray dryer, and then at 920 ° C. for 6 hours using a rotary kiln. The preliminary firing 2 was performed. The two calcined products thus obtained were pulverized for 6 hours by a wet ball mill to a volume average particle size of 5.1 μm, further granulated and dried by a spray dryer, and then at a temperature of 950 ° C. using an electric furnace. The main baking was performed for 16 hours. Through the pulverization step and the classification step, core material particles B having a volume average particle size of 31.1 μm were prepared. The BET specific surface area was 0.148.
The characteristics of the obtained core material particles B are as shown in Table 1.

<Manufacture of core particle C>
The production of the core particle C was performed as follows.
Fe ₂ O ₃ 72 parts by weight MnO ₂ 20 parts by weight Mg (OH) ₂ 7 parts by weight are mixed, pulverized in a wet ball mill for 28 hours, granulated and dried by a spray dryer, and then at 830 ° C. using a rotary kiln. 7 hours pre-baking 1 was performed. The pre-fired product thus obtained was pulverized with a wet ball mill for 2 hours to give a volume average particle size of 2.1 μm, further granulated and dried with a spray dryer, and then at 920 ° C. for 5 hours using a rotary kiln. The preliminary firing 2 was performed. The two calcined products thus obtained were pulverized with a wet ball mill for 5 hours to a volume average particle size of 5.4 μm, further granulated and dried with a spray dryer, and then heated at 860 ° C. using an electric furnace. The main baking was performed for 10 hours. Through the pulverization step and the classification step, core material particles C having a volume average particle size of 35.7 μm were prepared. The BET specific surface area was 0.236.
The properties of the obtained core material particles C are as shown in Table 1.

<Manufacture of core particle D>
The production of the core particle D was performed as follows.
Fe ₂ O ₃ 72 parts by weight MnO ₂ 20 parts by weight Mg (OH) ₂ 7 parts by weight are mixed, pulverized in a wet ball mill for 28 hours, granulated and dried by a spray dryer, and then at 830 ° C. using a rotary kiln. 7 hours pre-baking 1 was performed. The pre-baked product thus obtained was pulverized for 3 hours with a wet ball mill to a volume average particle size of 2.0 μm, further granulated and dried with a spray dryer, and then at 920 ° C. for 6 hours using a rotary kiln. The preliminary firing 2 was performed. The two calcined products thus obtained were pulverized for 6 hours by a wet ball mill to a volume average particle size of 4.8 μm, further granulated and dried by a spray dryer, and then heated at a temperature of 950 ° C. using an electric furnace. The main baking was performed for 18 hours. Through the pulverization step and the classification step, core material particles D having a volume average particle size of 36.1 μm were prepared. The BET specific surface area was 0.124.
The properties of the obtained core material particles D are as shown in Table 1.

<Manufacture of core particle E>
The production of the core particle E was performed as follows.
Fe ₂ O ₃ 72 parts by weight MnO ₂ 20 parts by weight Mg (OH) ₂ 7 parts by weight are mixed, pulverized in a wet ball mill for 28 hours, granulated and dried by a spray dryer, and then at 830 ° C. using a rotary kiln. 7 hours pre-baking 1 was performed. The calcined product thus obtained was pulverized for 2 hours with a wet ball mill to a volume average particle size of 2.1 μm, further granulated and dried with a spray dryer, and then at 920 ° C. for 6 hours using a rotary kiln. The preliminary firing 2 was performed. The two calcined products thus obtained were pulverized with a wet ball mill for 4 hours to a volume average particle size of 5.9 μm, further granulated and dried with a spray dryer, and then heated at 820 ° C. using an electric furnace. The main baking was performed for 10 hours. Through the pulverization step and the classification step, core material particles E having a volume average particle size of 38.0 μm were prepared. The BET specific surface area was 0.227.
The properties of the obtained core material particles E are as shown in Table 1.

[Production of coating resin layer forming liquids 1 to 11]
<Manufacture of coating resin layer forming liquid 1>
The production of the coating resin layer forming liquid 1 was performed as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 40: 60, weight average molecular weight Mw = 70000)
・ Carbon black (VXC72, manufactured by Cabot) 4 parts by weightToluene (manufactured by Wako Pure Chemical Industries, Ltd.) 300 parts by weight The above components and glass beads (particle size: 1 mm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming liquid 1 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 2>
The coating resin layer forming liquid 2 was manufactured as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 60: 40, weight average molecular weight Mw = 70000)
Carbon black (VXC72, Cabot) 4 parts by weight Toluene (Wako Pure Chemical Industries) 300 parts by weight The above components and glass beads (particle size: 1 mm, equivalent to toluene) in a sand mill (Kansai Paint Co., Ltd.) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming liquid 2 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 3>
The coating resin layer forming solution 3 was produced as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 20: 80, weight average molecular weight Mw = 70000)
・ Carbon black (VXC72, manufactured by Cabot) 4 parts by weightToluene (manufactured by Wako Pure Chemical Industries, Ltd.) 300 parts by weight The above components and glass beads (particle size: 1 mm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution 3 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 4>
The coating resin layer forming liquid 4 was produced as follows.
30 parts by weight of polycarbonate resin (copolymerization ratio is bisphenol A: bisphenol Z = 80: 20, weight average molecular weight Mw = 70000)
・ Carbon black (VXC72, manufactured by Cabot) 4 parts by weightToluene (manufactured by Wako Pure Chemical Industries, Ltd.) 300 parts by weight The above components and glass beads (particle size: 1 mm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution 4 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 5>
The coating resin layer forming solution 5 was produced as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 18: 82, weight average molecular weight Mw = 65000)
・ Carbon black (VXC72, manufactured by Cabot) 4 parts by weightToluene (manufactured by Wako Pure Chemical Industries, Ltd.) 300 parts by weight The above components and glass beads (particle size: 1 mm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution 5 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 6>
The coating resin layer forming liquid 6 was produced as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 82: 18, weight average molecular weight Mw = 75000)
・ Carbon black (VXC72, manufactured by Cabot) 4 parts by weightToluene (manufactured by Wako Pure Chemical Industries, Ltd.) 300 parts by weight The above components and glass beads (particle size: 1 mm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution 6 having a solid content of 10% by weight.

<Manufacture of Coating Resin Layer Forming Liquid 7> The coating resin layer forming liquid 7 was manufactured as follows.
Polycarbonate resin 29.5 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 50: 50, weight average molecular weight Mw = 75000)
Styrene acrylic resin 0.5 parts by weight (styrene: methyl methacrylate = 80: 20, weight average molecular weight Mw = 10 0000)
・ Carbon black (VXC72, manufactured by Cabot) 4 parts by weightToluene (manufactured by Wako Pure Chemical Industries, Ltd.) 300 parts by weight The above components and glass beads (particle size: 1 mm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution 7 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 8>
The coating resin layer forming liquid 8 was produced as follows.
Acrylic resin 30 parts by weight (copolymerization ratio is acrylic acid: methyl methacrylate: dimethylaminoethyl methacrylate = 1: 98: 1, weight average molecular weight Mw = 100000)
・ Carbon black (VXC72, manufactured by Cabot) 4 parts by weightToluene (manufactured by Wako Pure Chemical Industries, Ltd.) 300 parts by weight The above components and glass beads (particle size: 1 nm, the same amount as toluene) are added to a sand mill (manufactured by Kansai Paint). The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution 8 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 9>
The coating resin layer forming liquid 9 was produced as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 50: 50, weight average molecular weight Mw = 70000)
Carbon black (VXC72, Cabot) 4 parts by weight Toluene (Wako Pure Chemical Industries) 300 parts by weight The above components and glass beads (particle size: 1 nm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution 9 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 10>
The coating resin layer forming solution 10 was manufactured as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 52: 48, weight average molecular weight Mw = 70000)
Carbon black (VXC72, Cabot) 4 parts by weight Toluene (Wako Pure Chemical Industries) 300 parts by weight The above components and glass beads (particle size: 1 nm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred for 30 minutes at a rotational speed of 1200 rpm to prepare a coating resin layer forming solution 10 having a solid content of 10% by weight.

<Manufacture of coating resin layer forming liquid 11>
The coating resin layer forming liquid 11 was manufactured as follows.
Polycarbonate resin 30 parts by weight (copolymerization ratio is bisphenol A: bisphenol Z = 48: 52, weight average molecular weight Mw = 70000)
Carbon black (VXC72, Cabot) 4 parts by weight Toluene (Wako Pure Chemical Industries) 300 parts by weight The above components and glass beads (particle size: 1 nm, equivalent to toluene) in a sand mill (manufactured by Kansai Paint) The mixture was stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming liquid 11 having a solid content of 10% by weight.

[Manufacture of Carriers A to P]
<Manufacture of carrier A>
-100 parts by weight of core material particle A-12 parts by weight of the coating resin layer forming liquid is put into a vacuum degassing kneader, and the pressure is reduced to -200 mmHg at 50 ° C with stirring and mixed for 20 minutes. The mixture was stirred and dried at 90 ° C./−720 mmHg for 20 minutes, and sieved with a 75 μm mesh sieve to obtain carrier A.

<Manufacture of carrier B>
A carrier B was obtained in the same manner as the carrier A except that the coating resin layer forming liquid 2 was used.

<Manufacture of carrier C>
A carrier C was obtained in the same manner as the carrier A except that the coating resin layer forming liquid 3 was used.

<Manufacture of carrier D>
A carrier D was obtained in the same manner as the carrier A except that the coating resin layer forming liquid 4 was used.

<Manufacture of carrier E>
A carrier E was obtained in the same manner as the carrier A except that the coating resin layer forming solution 5 was used.

<Manufacture of carrier F>
A carrier F was obtained in the same manner as the carrier A except that the coating resin layer forming liquid 6 was used.

<Manufacture of carrier G>
A carrier G was obtained in the same manner as the carrier A except that the coating resin layer forming liquid 7 was used.

<Manufacture of carrier H>
A carrier H was obtained in the same manner as the carrier A except that the coating resin layer forming liquid 8 was used.

<Manufacture of carrier I>
Core material particle A 100 parts by weight Takenate D110N 3 parts by weight (manufactured by Mitsui Takeda Chemical, adduct type polyisocyanate)
・ 0.3 parts by weight of carbon black (VXC-72, manufactured by Cabot Corporation)
-Toluene (manufactured by Wako Pure Chemical Industries) 20 parts by weight Of the above materials, Takenate D110N was diluted with toluene, carbon black was added, and the mixture was stirred with a homogenizer for 6 minutes to prepare a resin solution. The resin solution and core particle A were placed in a vacuum degassing kneader and stirred at 80 ° C. for 30 minutes, and then the pressure was reduced to remove toluene, thereby forming a coating on the surface of the ferrite particles. Further, after adding 50 parts by weight of pure water, it was placed in a dryer at 160 ° C. for 4 hours to sufficiently cure the resin on the surface of the core material particles, whereby Carrier I was obtained.

<Carrier J>
Carrier K was obtained in the same manner as carrier A, except that coating resin layer forming solution 9 was used.

<Carrier K>
Carrier K was obtained in the same manner as carrier A except that coating resin layer forming solution 10 was used.

<Carrier L>
A carrier L was obtained in the same manner as the carrier A except that the coating resin layer forming liquid 11 was used.

<Carrier M>
Carrier M was obtained in the same manner as carrier A except that core particle B was used.

<Carrier N>
Carrier N was obtained in the same manner as carrier A except that core material particle C was used.

<Carrier O>
A carrier O was obtained in the same manner as the carrier A except that the core particle D was used.

<Carrier P>
A carrier P was obtained in the same manner as the carrier A except that the core particle E was used.

[Production of colored particles]
<Production of colored particles A (Kuro)> (grinding method)
Styrene-nBA resin 100 parts by weight (Tg = 59 ° C., Mn = 4200, Mw = 25000)
・ 3 parts by weight of carbon black (Mogal L: manufactured by Cabot)
The above mixture was kneaded with an extruder, pulverized with a jet mill, and then dispersed with an air classifier, and colored particles A (Kuro) having a volume average particle size of 5.2 μm, a spherical coefficient of 137.9, and GSDv = 1.24. ) Was produced.

<Production of colored particles B (Kuro)> (wet process)
-Preparation of resin dispersion (1)-
・ Styrene 370 parts ・ N-butyl acrylate 30 parts ・ Acrylic acid 7 parts ・ 10 Dodecanethiol 25 parts ・ Carbon tetrabromide 4 parts by weight or more mixed and dissolved, nonionic interface In a flask, 6 parts by weight of an activator (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and 10 parts by weight of an anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved in 550 g of ion-exchanged water. 50 parts by weight of ion-exchanged water in which 4 g of ammonium persulfate was dissolved was added to the mixture while being slowly mixed for 10 minutes. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the contents reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin dispersion (1) in which resin particles having a volume average particle diameter of 157 nm, Tg = 59 ° C., and weight average molecular weight Mw = 13000 were dispersed was prepared.

-Preparation of resin dispersion (2)-
-280 parts by weight of styrene-125 parts by weight of n-butyl acrylate-6 g of nonionic surfactant (Nonipol 400: manufactured by Sanyo Kasei Co., Ltd.) Anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 12 g dissolved in ion-exchanged water 550 g was emulsified and dispersed in a flask, and 3 g ammonium persulfate was dissolved in this while slowly mixing for 10 minutes. 50 g of ion-exchanged water was added. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the contents reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin dispersion (2) in which resin particles having a volume average particle diameter of 108 nm, Tg = 54 ° C., and weight average molecular weight Mw = 540000 was dispersed was prepared.

-Preparation of colorant dispersion (1)-
・ 55 parts by weight of carbon black (Mogal L: manufactured by Cabot)
-Nonionic surfactant 5 parts by weight (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.)
・ Ion-exchanged water Mixing and dissolving 200 parts by weight or more of components, disperse using a homogenizer (Ultra Turrax T50: manufactured by IKA) for 10 minutes, and a colorant (carbon black) having a volume average particle size of 255 nm ) A colorant dispersion (1) in which particles were dispersed was prepared.

-Release agent dispersion-
・ 52 parts by weight of paraffin wax (HNP0190: Nippon Seiwa Co., Ltd., melting point 85 ° C.)
Cationic surfactant 6 parts by weight (Sanisol B50: manufactured by Kao Corporation)
・ Ion-exchanged water 200 parts by weight or more of components were heated to 95 ° C. and dispersed in a round stainless steel flask for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), followed by pressure discharge type A release agent dispersion liquid in which release agent particles having a volume average particle diameter of 555 nm were dispersed was prepared by dispersing with a homogenizer.

-Production of colored particles B (Kuro)-
Resin dispersion (1) 120 parts by weight Resin dispersion (2) 80 parts by weight Colorant dispersion (1) 200 parts by weight Release agent dispersion 40 parts by weight Cationic surfactant (Sanisol B50: manufactured by Kao Corporation) ) 1.5 parts by weight The above components were mixed and dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then the inside of the flask was stirred in a heating oil bath. While heating to 50 ° C. After maintaining at 45 ° C. for 20 minutes, it was confirmed with an optical microscope that it was confirmed that aggregated particles having a volume average particle diameter of about 4.1 μm were formed. Further, 60 g of the resin dispersion liquid (1) was gradually added to the above mixed liquid. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 30 minutes. Observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of about 4.9 μm were formed.
After adding 3 g of an anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to the above mixture, the stainless steel flask was sealed and heated to 105 ° C. with stirring using a magnetic seal. Hold for 4 hours. Then, after cooling, the reaction product was filtered, washed thoroughly with ion-exchanged water, and then dried to produce colored particles B (Kuro). The obtained colored particles B (Kuro) had a shape factor of 119.3, a volume average particle size of 5.3 μm, and GSDv = 1.21.

<Preparation of colored particles C (Cyan)>
In the production method of the colored particles B (Kuro), the following colorant dispersion (2) was used instead of the colorant dispersion (1), and the shape factor was 119.4, the volume average particle size was 5.5 μm, and GSDv. = 1.20 colored particles C (Cyan) were produced.

-Preparation of colorant dispersion (2)-
Cyan pigment (CI Pigment Blue 15: 3: manufactured by Dainichi Seika Co., Ltd.) 72 parts by weight Nonionic surfactant 6 parts by weight (Nonipol 400: manufactured by Sanyo Kasei Co., Ltd.)
-Ion-exchanged water 200 parts by weight The above components are mixed and dissolved, and dispersed for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA). The colorant (Cyan pigment) has an average particle size of 255 nm. A colorant dispersant (2) in which particles were dispersed was prepared.

<Preparation of colored particles D (Magenta)>
In the production method of the colored particles B (Kuro), the following colorant dispersion (3) was used instead of the colorant dispersion (1), and the shape factor was 120.6, the volume average particle size was 5.4 μm, GSDv = 1.19 colored particles D (Magenta) were produced.

-Preparation of colorant dispersion (3)-
・ Magenta pigment (CI Pigment Red 122: manufactured by Dainippon Ink & Chemicals, Inc.) 72 parts by weight ・ Nonionic surfactant 6 parts by weight (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.)
-Ion-exchanged water 200 parts by weight or more of components are mixed and dissolved, and dispersed for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), and a colorant (Magenta pigment) having an average particle size of 253 nm A colorant dispersant (3) in which particles were dispersed was prepared.

<Preparation of colored particles E (Yellow)>
In the production method of the colored particles B (Kuro), the following colorant dispersion (4) was used instead of the colorant dispersion (1), and the shape factor 122, volume average particle size 5.4 μm, GSDv = 1 20 colored particles E (Yellow) were produced.

-Preparation of colored dispersion (4)-
Yellow pigment (CI Pigment Yellow 180: manufactured by Dainippon Ink & Chemicals) 105 parts by weight Nonionic surfactant 6 parts by weight (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.)
-Ion-exchanged water 200 parts by weight or more of components are mixed and dissolved, and dispersed for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), and a colorant (Yellow pigment) having an average particle size of 254 nm A colorant dispersant (4) in which particles were dispersed was prepared.

[Production of Toners A to N]
<Manufacture of toner A>
100 parts by weight of colored particles B (Kuro), 0.5 parts by weight of hydrophobic titanium oxide fine particles having a BET specific surface area of 100 m ² / g as external additives and 3 parts by weight of hydrophobic silica fine particles having a volume average particle size of 0.4 μm After mixing for 10 minutes at a peripheral speed of 32 m / s with a Henschel mixer, coarse particles were removed using a sieve having a mesh size of 45 μm to obtain toner A.

<Manufacture of toner B>
In the production of the toner A, a toner B was obtained in the same manner as in the production of the toner A, except that the colored particles C (Cyan) were used instead of the colored particles B (Kuro).

<Manufacture of toner C>
In the production of the toner A, a toner C was obtained in the same manner as in the production of the toner A, except that the colored particles D (Magenta) were used instead of the colored particles B (Kuro).

<Manufacture of toner D>
In the production of the toner A, a toner D was obtained in the same manner as in the production of the toner A, except that the colored particles E (Yellow) were used instead of the colored particles B (Kuro).

<Manufacture of toner E>
100 parts by weight of colored particles A (Kuro), 0.5 parts by weight of hydrophobic titanium oxide fine particles having a BET specific surface area of 100 m ² / g as external additives, and 3 parts by weight of hydrophobic silica fine particles having a volume average particle size of 0.1 μm After mixing with a Henschel mixer at a peripheral speed of 32 m / s for 10 minutes, coarse particles were removed using a sieve of 45 μm mesh, and toner E was obtained.

<Manufacture of toner F>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A, except that the hydrophobic silica fine particles having a volume average particle size of 0.2 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.1 μm. F was obtained.

<Manufacture of toner G>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A, except that the hydrophobic silica fine particles having a volume average particle size of 0.27 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.2 μm. G was obtained.

<Manufacture of toner H>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A except that the hydrophobic silica fine particles having a volume average particle size of 0.35 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.2 μm. H was obtained.

<Manufacture of Toner I>
In the production of the toner A, a toner is produced in the same manner as in the production of the toner A, except that the hydrophobic silica fine particles having a volume average particle size of 0.19 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.2 μm. I was obtained.

<Manufacture of toner J>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A, except that the hydrophobic silica fine particles having a volume average particle size of 0.36 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.2 μm. J was obtained.

<Manufacture of toner K>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A, except that the hydrophobic silica fine particles having a volume average particle diameter of 0.05 μm are used instead of the hydrophobic silica fine particles having a volume average particle diameter of 0.2 μm. K was obtained.

<Manufacture of toner L>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A except that the hydrophobic silica fine particles having a volume average particle size of 0.12 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.2 μm. L was obtained.

<Manufacture of toner M>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A, except that the hydrophobic silica fine particles having a volume average particle size of 0.04 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.2 μm. M was obtained.

<Manufacture of toner N>
In the production of the toner A, the toner is produced in the same manner as in the production of the toner A, except that the hydrophobic silica fine particles having a volume average particle size of 0.21 μm are used instead of the hydrophobic silica fine particles having a volume average particle size of 0.2 μm. N was obtained.

[Manufacture of developer]
100 parts by weight of the carrier A to P and 5 parts by weight of the toners A to N were stirred for 20 minutes at 40 rpm using a V blender, and sieved with a 177 μm sieve screen to obtain a developer.

[Evaluation methods]
Using the developer for developing an electrostatic latent image obtained in the production of the developer, the developability and transferability were evaluated with a modified Docu Color 1250 manufactured by Fuji Xerox. The contents of the modification are to operate even when the developer is contained only in the black developing machine.

<Evaluation of initial developability>
TC 5% developer is allowed to stand overnight at the specified temperature and humidity (29 ° C 90%, 10 ° C 20%), copy the image with two 2cm, 5cm patches, and develop the development amount with a hard stop. It was measured. The developed portions at two locations on the photoreceptor were each transferred onto the tape using adhesiveness, the weight of the toner-attached tape was measured, and the developed amount was determined by averaging after subtracting the tape weight. Preferred values are 4.5~5.0g / m ^2, the ^{4.5~5.0g / m 2 ◎, 5.0~5.5g /} m 2 and 4.0~4.5g / m ² was marked with ◯, 5.5-6.0 g / m ² and 3.5-4.0 g / m ² were marked with Δ, and other values were marked with x.

<Evaluation of developability after 10,000 sheets>
Take 10,000 copies at a specified temperature and humidity (29 ° C 90%, 10 ° C 20%) with a developer, and let it stand overnight, then copy an image with two 2cm and 5cm patches, The development amount was measured with a hard stop. The developed portions at two locations on the photoreceptor were each transferred onto the tape using adhesiveness, the weight of the toner-attached tape was measured, and the developed amount was determined by averaging after subtracting the tape weight. Preferred values are 4.5~5.0g / m ^2, the ^{4.5~5.0g / m 2 ◎, 5.0~5.5g /} m 2 and 4.0~4.5g / m ² was marked with ◯, 5.5-6.0 g / m ² and 3.5-4.0 g / m ² were marked with Δ, and other values were marked with x.

<Evaluation of fogging at the initial stage and after 10,000 sheets>
Similarly, the background portion was transferred onto a tape, and the number of toners per 1 cm ² was counted, and 100 or less was evaluated as ◯, 100 to 500 was evaluated as Δ, and the case where it was larger was evaluated as ×.

<Evaluation of transferability at initial stage and after 10,000 sheets>
At the end of the transfer process, a hard stop is performed, the toner weight on the two intermediate transfer members is transferred onto the tape in the same manner as described above, the toner adhering tape weight is measured, and the tape weight is subtracted and then averaged. a was obtained, and similarly, the toner amount b remaining on the photoreceptor was obtained, and the transfer efficiency was obtained by the following equation.
Transfer efficiency η (%) = a 100 / (a + b)
The transfer efficiency was evaluated as η ≧ 99%, η ≧ 99% was evaluated as ◎, 95% ≦ η <99% as ○, 90% ≦ η <95% as Δ, and η <90% as ×.

  The results after the initial and 10,000 sheets are shown in Tables 2 to 5 below.

  As can be seen from the results in Table 2, by using the developer of the embodiment, it is possible to obtain long-term stable developability, image quality, and transferability.

  As is apparent from the results in Tables 3 and 4, by using the developer of the present embodiment, it is possible to obtain stable developability, image quality, and transferability for a long period of time.

  As is apparent from the results in Table 5, by using the developer of this embodiment, it is possible to obtain long-term stable developability, image quality, and transferability.

  5 parts by weight of toner having a shape factor in the range shown in Table 6 and 100 parts by weight of carrier A were stirred for 20 minutes at 40 rpm using a V blender, and sieved with a 177 μm sieve screen to obtain a developer. . Similar to the evaluation method, the initial evaluation and the evaluation after 10,000 sheets were performed. The results are shown in Table 6.

  As is apparent from the results in Table 6, by using the developer of the present embodiment, it is possible to obtain long-term stable developability, image quality, and transferability.

1 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment (first embodiment) of an image forming apparatus. It is sectional drawing which shows schematically the basic composition of other suitable one Embodiment (2nd embodiment) of an image forming apparatus. It is sectional drawing which shows schematically the basic composition of other suitable one Embodiment (3rd embodiment) of an image forming apparatus.

Explanation of symbols

10, 100, 200... Image forming apparatus 12, 110, 212... Electrostatic latent image holder 14, 120, 214... Charging means 16, 130, 216. , 140, 218... Developing means 141... Developer containing container 146... Developer supplying means 148. , 180, 226... Fixing means 28, 147... Cartridge 210.

Claims (6)

A toner composition having toner particles containing at least a colorant and a binder resin, and inorganic particles;
A core material particle and a carrier having a coating resin layer that coats the surface of the core material particle,
The coating resin layer contains a copolymer obtained by polymerizing at least a polymerizable monomer represented by the following general formula (I) and a polymerizable monomer represented by the following general formula (II), and A developer for developing an electrostatic latent image, wherein the copolymer has a copolymerization ratio of 20/80 to 80/20.

  The developer for developing an electrostatic latent image according to claim 1, wherein the inorganic particles have a volume average particle diameter of 0.05 μm or more and 0.35 μm or less. The developer for developing an electrostatic latent image according to claim 1, wherein the core particles satisfy the following formula (1).
Formula (1): 3.5 <= A / a <= 6.5
[Wherein, in formula (1), A represents the BET specific surface area (unit: m ² / g) of the core particle, a represents the spherical equivalent specific surface area (unit: m ² / g) of the core particle, The spherical equivalent specific surface area a is defined as a = 6 / (d, where d (unit: μm) is the volume average particle diameter of the core particles and ρ (unit: dimensionless) is the true specific gravity of the core particles. Xρ). ]   At least a developer for developing the electrostatic latent image formed on the surface of the electrostatic latent image holding member and supplying it to a developing means for forming a toner image; A developer cartridge for developing an electrostatic latent image, wherein the developer is the developer for developing an electrostatic latent image according to any one of claims 1 to 3.   A developer for developing an electrostatic latent image according to any one of claims 1 to 3 is accommodated, and an electrostatic latent image formed on a surface of an electrostatic latent image holding member is stored in the electrostatic latent image. Developing means for developing a toner image by developing with an image developing developer, electrostatic latent image holding member, charging means for charging the surface of the electrostatic latent image holding member, and surface of the electrostatic latent image holding member And at least one selected from the group consisting of cleaning means for removing the remaining toner, and a process cartridge that is detachable from the image forming apparatus.   At least an electrostatic latent image holding body, a charging means for charging the surface of the electrostatic latent image holding body, and an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the electrostatic latent image holding body, A developing unit that develops the electrostatic latent image with a developer to form a toner image; a transfer unit that transfers the toner image to a recording medium; and a fixing unit that fixes the toner image on the recording medium. An image forming apparatus, wherein the developer is the developer for developing an electrostatic latent image according to any one of claims 1 to 3.

Images