JP2004102261A - Electrostatic charge image developing toner, two-component developer and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner used for a roller heat fixing method and excellent in low temperature fixability and anti-offsetting property and capable of preventing a deterioration in a developer by selecting a resin and a wax for the toner under attention to the relation among 1/2 outflow temperature T, dielectric loss and fixing control temperature. <P>SOLUTION: The toner used for a roller heat and pressure fixing device comprises at least a wax, a binder resin and carbon black, and when the 1/2 outflow temperature T<SB>1/2</SB>(°C) of the toner measured with an overhead flow tester is ≤160°C, the relation among the T<SB>1/2</SB>of the toner, dielectric loss tanδ and the fixing control temperature T (°C) of the fixing device satisfies expression (1): T≤A×T<SB>1/2</SB>+B×tanδ-105.0 (where A=1.9 and B=3.8×10<SP>3</SP>) and expression (2): 4.0×10<SP>-3</SP>≤tanδ≤6.5×10<SP>-3</SP>. <P>COPYRIGHT: (C)2004,JPO

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developing toner used for electrophotography, electrostatic recording, and the like, and more particularly, to an electrostatic image developing toner used for a heat and pressure fixing device, and a two-component developer including the toner and a carrier. And a process cartridge provided with a developer.

画像 Image formation using a heat-press fixing device is widely known and used in printers, copiers and the like.

一方 While the miniaturization of devices has been progressing, many attempts have been made for low-temperature fixing from the viewpoint of energy saving. For low-temperature fixing, low-temperature fixing of toner to be used is one of the important technologies along with low power consumption of the apparatus. In general, in order to fix a toner at a low temperature, it is known to use a low softening substance as a binder resin used for the toner.

Here, the heat and pressure fixing method is a method widely used from a low speed to a high speed copying machine, but it is used by changing conditions such as a control temperature, a pressing force, and a nip width of a fixing device according to a copying speed. ing. In particular, it is known that the fixing control temperature greatly affects the fixing property of an image, but it is also known that the actual fixing roller temperature fluctuates depending on copying conditions with respect to the fixing control temperature in a copying machine. For example, in the case where a size smaller than the width of the transfer paper of the largest copy size is continuously copied with respect to the width of the fixing roller, in a region where the transfer paper does not pass, the fixing roller temperature is about 20 to 30 ° C. lower than the fixing control temperature. The temperature rises. When the transfer paper having the largest copy size width is copied in such a state where only the end temperature of the fixing roller is high, when the fixing roller contacts the toner on the transfer paper, the toner adheres to the fixing roller, and the adhered toner is removed. Is transferred to the subsequent transfer paper, that is, a so-called high-temperature offset phenomenon occurs.

It is generally known that this offset phenomenon is likely to occur when the binder resin is a low-temperature softening substance. Therefore, the following proposals have conventionally been made to suppress this offset phenomenon. JP-B-55-6895 (Patent Document 1) and JP-A-56-98202 (Patent Document 2) describe a method for suppressing the offset phenomenon by increasing the width of the molecular weight distribution of the binder resin. Have been. However, in general, the degree of polymerization of the resin increases, and the fixing temperature used must be set high.

Further, Japanese Patent Publication No. 57-493 (Patent Document 3), Japanese Patent Application Laid-Open No. 50-44836 (Patent Document 4), and Japanese Patent Application Laid-Open No. 57-37353 (Patent Document 5) disclose a non-linear resin. A method for suppressing the offset phenomenon by crosslinking or crosslinking is described. Also, JP-A-61-213858 (Patent Document 6), JP-A-1-295269 (Patent Document 7), and JP-A-1 Japanese Patent Application Laid-Open No. 30061 (Patent Document 8), Japanese Patent Application Laid-Open No. 1-302267 (Patent Document 9) and Japanese Patent Application Laid-Open No. 3-96964 (Patent Document 10) improve the offset phenomenon by crosslinking a polyester resin with metal ions. A method is described.

In any of these methods, although the offset resistance is improved, the inherent fixability of the binder resin is reduced, and since the entanglement of the polymer molecules is strong, the resin component due to cross-linking represented by the tetrahydrofuran-insoluble component is used as a coloring agent or the like. This makes it difficult to disperse the charge control agent in the binder resin, and also lowers the pulverizability of the kneaded toner during the production of the toner.

For the purpose of improving such offset resistance, Japanese Patent Application Laid-Open No. Hei 5-297630 (Patent Document 11) specifies a 1/2 outflow temperature range using an elevated flow tester using a specific binder resin. However, the offset resistance is not sufficient because it is largely related to the releasability of the toner, that is, the ease of exudation of the wax, in addition to the melt viscosity of the toner.

In addition, due to the recent miniaturization of copiers and printers, the temperature inside the developing machine tends to rise, and the preservation of toner at high temperatures is desired to be higher than ever. Specific examples include prevention of toner aggregation and blocking, but the wax dispersed in the toner excessively bleeds to the toner surface due to thermal stress in the developing machine, and particularly the carrier surface used in the two-component developing method. And the image quality is deteriorated, such as toner scattering due to a decrease in the charge of the developer, background contamination, or a decrease in the image density due to a decrease in the control toner concentration. Therefore, in order to make the wax dispersed in the toner less likely to bleed at a high temperature, it is necessary to disperse the wax so as not to be exposed on the toner surface, or to use a material having a high melting point of the wax itself. However, these methods also impair the low-temperature fixability.

Therefore, although toners that can be fixed at a low temperature, have excellent hot offset, and prevent deterioration of the developer have been proposed, they have not yet reached a desired level.

JP-B-55-6895 JP-A-56-98202 JP-B-57-493 JP-A-50-44836 JP-A-57-37353 JP-A-61-213858 JP-A-1-295269 JP-A-1-36061 JP-A-1-302267 JP-A-3-96964 JP-A-5-297630

The present invention has been made to solve the above problems, and an object of the present invention is to provide a toner that is excellent in low-temperature fixability and anti-offset property and that prevents developer deterioration. To provide a two-component developer and a process cartridge.

The present inventors have conducted intensive studies in order to prevent low temperature fixing property and offset resistance and to prevent the deterioration of the developer, and as a result, the toner containing carbon black as a wax and a binder resin and a coloring agent has been described. The 1/2 outflow temperature T _1/2 (° C.) of the toner by the elevated flow tester is 160 ° C. or less, and the T _{1/2 of} the toner, the dielectric loss tan δ, and the fixing control temperature T (° C.) of the fixing device. It has been found that the above problem can be solved by satisfying the expressions (1) and (2) with respect to (1) and (2), and the present invention has been completed.
T ≦ A × T _1/2 + B × tan δ−105.0 (1)
4.0 × 10 ⁻³ ≦ tan δ ≦ 6.5 × 10 ⁻³ (2)
A = 1.9, B = 3.8 × 10 ³
According to the present invention, the following (1) to (6) are provided.

(1) In a toner used for a fixing method in which a fixing roller is heated by using a heater, and is fixed by a pressing force against a pressure roller and heat from the fixing roller, the toner includes at least wax, a binder resin, and carbon as a colorant. When the toner contains black and the outflow temperature T _1/2 (° C.) of the toner measured by an elevated flow tester is 160 ° C. or less, T _{1/2 of} the toner, dielectric loss tan δ, and A toner for developing electrostatic charge, wherein the relationship with the fixing control temperature T (° C.) satisfies the formulas (1) and (2).
T ≦ A × T _1/2 + B × tan δ−105.0 ・ ・ ・ ・ ・ (1)
4.0 × 10 ⁻³ ≦ tan δ ≦ 6.5 × 10 ⁻³ (2)
A = 1.9, B = 3.8 × 10 ³

(2) In the invention according to claim 2, the binder resin used for the toner is at least a polyester resin, the polyester resin contains 10 to 30 wt% of a THF-insoluble component, and the THF-insoluble component in the toner is 4% by weight. The toner for developing an electrostatic image according to the above (1), wherein the toner is contained in an amount of from about 12% by weight to about 12% by weight.

(3) The toner for developing an electrostatic image according to the above (2), wherein the temperature at which the storage elastic modulus G ′ of the toner is 10 ³ Pa is 180 ° C. or higher.

(4) The wax used for the toner is at least one of carnauba wax, rice wax, and ester wax, and the raw material particle size of the wax is 100 to 600 μm. The toner for developing an electrostatic image according to any of 3).

(5) A two-component developer comprising the toner according to any one of (1) to (4) and a carrier.

(6) In a process cartridge which integrally supports a photosensitive member and at least one unit selected from a charging unit, a developing unit, and a cleaning unit and is detachable from an image forming apparatus main body, the developer used for the developing unit is: A process cartridge comprising a one-component developer comprising the toner according to any one of the above (1) to (4) or a two-component developer according to the above (5).

According to the first aspect of the present invention, in a toner used for a roller heating / pressing fixing device, the toner contains at least a wax, a binder resin, and carbon black, and a half flow temperature T of the toner by an elevated flow tester. _{When 1/2} (° C.) is 160 ° C. or less, the relationship between T _{1/2 of the} toner, the dielectric loss tan δ, and the fixing control temperature T (° C.) of the fixing device is expressed by the above equation (1). By satisfying (2) and (3), the tan δ, which is a wax dispersibility index, is set in the range defined by the equation (2), the offset property and the carrier spent property are kept in a good range, and background stain, toner scattering, image density It is possible to obtain a toner that can prevent a decrease and the like, is excellent in offset resistance and low-temperature fixability, and exhibits excellent effects in image stability.

According to the invention of claim 2, the binder resin used in the toner is at least a polyester resin, the polyester resin contains 10 to 30 wt% of a THF insoluble component, and the THF insoluble component in the toner is 4 to 12 wt%. %, It can have an appropriate elastic component after melt-kneading, and by using a polyester resin as the binder resin, it is possible to ensure low-temperature fixability.

According to the third aspect of the present invention, the temperature at which the storage elastic modulus G ′ of the toner reaches 10 ³ Pa is 180 ° C. or higher, so that a toner with further improved hot offset properties can be obtained.

According to the fourth aspect of the present invention, the wax used for the toner is at least one of carnauba wax, rice wax, and ester wax, and the raw material particle size of the wax is 100 to 600 μm. Use of a wax makes it possible to obtain a toner having excellent low-temperature fixability even with a small amount of wax.

According to the fifth aspect of the invention, the use of the toner as the toner of the two-component developer provides the same excellent effects as described above.

According to the invention of claim 6, since the toner or the two-component developer is mounted on the process cartridge, the same excellent effects as described above can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.
First, the configurations of the toner and the developer used in the present invention will be described.
The present invention relates to a toner in which at least a binder resin and a wax are dispersed, a 1/2 outflow temperature T _1/2 (° C.) of the toner by an elevated flow tester, a dielectric loss tan δ of the toner, and fixing control of the fixing device. The relationship with the temperature T (° C.) satisfies the equations (1) and (2).
T ≦ A × T _1/2 + B × tan δ−105.0 (1)
4.0 × 10 ⁻³ ≦ tan δ ≦ 6.5 × 10 ⁻³ (2)
A = 1.9, B = 3.8 × 10 ³

(4) Generally, the higher the 1/2 outflow temperature of the toner by the elevated flow tester, the higher the offset resistance. However, the offset resistance of toner of the same material may be different even at the same 流出 outflow temperature, so that it is not sufficient as an index of the offset resistance. This indicates that even if the toner melt viscosity, that is, the viscoelasticity is the same, the toner releasability is different.

The present inventors paid attention to these points, prepared a toner by changing the THF insoluble content in the binder resin, and kneading conditions, and evaluated the offset resistance. The toner release property and the wax dispersibility were evaluated. It was found that there was a relationship, and that the dispersibility of the wax was indicated by the electrical dielectric loss of the toner. This electric dielectric loss tan δ is defined by the following equation (3). In the case of a toner in which conductive fine particles such as carbon black are dispersed, this has been conventionally treated as an index of carbon dispersibility, but it has been found that the dispersion diameter of wax also has a correlation. Further, since the offset property changes depending on the fixing control temperature, it is necessary to include a relationship with the toner offset property index. Therefore, the anti-offset property required for the toner needs to satisfy the above expression (1). Was found from the experiment. When the T _1/2 temperature of the toner is higher than 160 ° C., the low-temperature fixability is significantly reduced.

tan δ = A / (2πf × C × R) (3)
A: Constant determined by measuring instrument and thickness of sample to be measured f: Measurement frequency C: Toner dielectric constant R: Toner volume resistivity

The measurement was carried out using an elevated flow tester (Shimadzu flow tester CFT-500 type, manufactured by Shimadzu Corporation). First, a 1.0 g sample weighed using a pressure molding machine was heated at a rate of 3.0 ° C./min. The plunger was pushed out from a nozzle having a plunger load of 10 kgf / cm ³ , a diameter of 0.5 mm and a length of 1 mm, and the plunger descent amount of the flow tester was measured.

At this time, when the height of the S-shaped curve in the plunger descent amount-temperature curve of the flow tester (refer to FIG. 2: flow tester outflow curve) is h, the temperature at h / 2 is １ ／ point, Let Ts be the softening point and _{let the} temperature T _fb at the sample outflow start point be the outflow start temperature.
The dielectric loss is calculated by the AC bridge method. 3 g of the toner is formed into a pellet having a thickness of about 3 mm. The pellet was measured for volume specific resistance (Ωcm) and dielectric constant at 1 KHz using a TR-10C dielectric loss measuring device, a WBG-9 oscillator, a BDA-9 equilibrium point detector, and an SE-30 electrode manufactured by Ando Electric Co., Ltd. Measure and calculate tan δ.

Next, the characteristics of the toner containing the wax vary greatly depending on the dispersion state of the wax. When the wax has a small particle size and is uniformly dispersed, the ratio of the amount of the wax present on the toner surface becomes equal to the amount of the included wax. However, when the toner has a large particle size, the ratio of the amount of wax existing on the toner surface becomes larger than the amount of wax included. The cause of this is that when the kneaded toner is pulverized and atomized, it is often pulverized by external force such as mechanical impact, impact by jet stream, etc., in which case the weakest part inside breaks down, which is wax Therefore, when the wax has a large particle size, the amount of wax on the toner surface increases. In such a toner, the spent on the carrier proceeds more.

Accordingly, it has been found that tan δ, which is an index of wax dispersibility, needs to be in the range defined by the formula (2) from the viewpoint of offset properties and carrier spent properties, that is, background stain, toner scattering, image density reduction and the like. . When tan δ is less than 4.0 × 10 ⁻³ , that is, when the wax is in an overdispersed state, the releasability decreases, so that even if the formula (1) is satisfied, the low-temperature fixability and the offset resistance decrease. . If tan δ exceeds 6.5 × 10 ⁻³ , the dispersion state of the wax is poor, the amount of wax on the toner surface at the pulverized interface is large, and carrier spent due to bleeding of the wax due to thermal stress is caused.

In order for the 流出 outflow temperature and tan δ of the toner to satisfy the expressions (1) and (2), it is necessary that an appropriate share can be given at the time of melt-kneading, and that the toner has an appropriate elastic component after the melt-kneading. For this reason, the THF content of the binder resin is preferably 10 to 30 wt%, and the amount of the THF-insoluble component in the toner is preferably 4 to 12 wt%. In order to ensure low-temperature fixability, it is preferable to use a polyester resin as the binder resin.

The THF-insoluble matter is obtained by finely pulverizing the toner or the binder resin, passing through a 40-mesh sieve, collecting a 5.00 g sample, placing the sample in a container together with 5.00 g of filter aid Radiolite, and adding THF (tetrahydrofuran) to the container. Inject 100 g and dissolve well. Next, a filter paper having a diameter of 7 cm (No. 2) is placed in a pressure filter, and the sample solution is filtered. After the outflow of the solution is completed, the residue on the filter paper is placed in a vacuum dryer and dried at 80 to 100 ° C. under a pressure of 100 mmHg for 10 hours. The total weight of the dried product thus obtained is measured, and the THF-insoluble content (%) is calculated.

Further, the hot offset property of the toner of the present invention is further improved by setting the temperature at which the storage elastic modulus in the viscoelasticity measurement is 10 ³ Pa to 180 ° C. or higher. Here, as the viscoelasticity measurement conditions, the temperature at which the storage elasticity becomes 1000 Pa when the toner is formed into pellets having a thickness of about 2 mm, the frequency is 1 Hz, the stress is 2000 Pa, and the temperature is raised to 50 to 230 ° C. is the viscoelasticity curve data. To analyze.

Further, as described above, the particle size of the toner and the carrier has been reduced for the purpose of improving the image quality, and particularly in the case of the above-described development conditions, the hazard that the developer receives mechanically becomes large. When a toner having a large particle size is used, spent on the carrier surface is promoted.

(4) When the amount of wax on the toner surface is simply reduced in order to solve the above-mentioned problem, a fixing offset occurs. However, when carnauba wax, rice wax, or ester wax is used as the wax component in the toner, low-temperature fixability is excellent even with a small amount of wax. Therefore, it is important to use carnauba wax and / or rice wax and / or synthetic ester wax as the wax component.

Carnauba wax is a natural wax obtained from the leaves of carnauba palm, and a low-acid-type wax from which free fatty acids have been eliminated is particularly preferred because it can be uniformly dispersed in a binder resin. Rice wax is a natural wax obtained by refining crude wax produced in a dewaxing or wintering process when refining rice bran oil extracted from rice bran.

Synthetic ester wax is synthesized from a monofunctional linear fatty acid and a monofunctional linear alcohol by an ester reaction. These wax components are used alone or in combination. The addition amount of the wax component is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the binder resin.

In the present invention, it is important that the average particle size of the carnauba wax and / or the rice wax and / or the synthetic ester wax is 100 to 600 μm. It is very desirable that the wax component is uniformly dispersed in the toner with a desired particle size. A preferable dispersion diameter is about 0.1 to 5 μm. However, the raw material wax particles often have a very wide particle size distribution.

A toner using such a wax has a non-uniform wax dispersion diameter and a particle size distribution of about 0.01 to 50 μm.
By setting the wax to 100 to 600 μm, a desired dispersion diameter can be obtained. When the average particle diameter of the wax exceeds 600 μm, the dispersion diameter in the toner increases, and the filming property, spent property, and heat-resistant storage stability deteriorate. When the average particle diameter of the wax is less than 100 μm, the dispersion diameter in the toner becomes small, and the low-temperature fixing property and the offset property deteriorate. The average particle diameter of the wax raw material measured using LA-920 manufactured by Horiba, Ltd. under the conditions of a circulation speed scale of 5 to 7 and a dispersion medium of methanol is used.

The dispersion diameter of the wax in the toner is determined by image analysis of a photographic image of the wax particles taken by a transmission scanning electron microscope of the toner using an image analyzer Luzex IIIU (manufactured by NIRECO).

従 来 In addition to the polyester resin, all conventionally known resins can be used as the binder resin used in the present invention. For example, styrene, poly-α-stillstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene Styrene such as maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer Resin (monopolymer or copolymer containing styrene or styrene substituent), epoxy resin, vinyl chloride resin, rosin-modified maleic resin, phenol resin, polyethylene resin, polypropylene resin, petroleum resin, polyurethane resin, ketone resin, Ethylene-ethyl acrylate Coalescence, xylene resin, polyvinyl butyrate resin and the like. The method for producing these resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization and the like can be used.

As the external additive, inorganic fine particles can be preferably used. The primary particle size of the inorganic fine particles is preferably from 5 μm to 2 μm, and particularly preferably from 5 μm to 500 μm. Further, the specific surface area by the BET method is preferably from 20 to 500 m ² / g. The use ratio of the inorganic fine particles is preferably from 0.01 to 5% by weight of the toner, and particularly preferably from 0.01 to 2.0% by weight.

Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, and diatomaceous Examples include earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

In addition, polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, or dispersion polymerization, polycondensation systems such as methacrylate and acrylate copolymers, silicone, benzoguanamine, and nylon, and thermosetting resins Polymer particles.

(4) Such a fluidizing agent is subjected to a surface treatment to increase hydrophobicity and prevent deterioration of fluidity and charging properties even under high humidity. For example, a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate-based coupling agent, an aluminum-based coupling agent, and the like are mentioned as preferable surface treatment agents.

As a cleaning improver for removing the developer after transfer remaining on the photoreceptor and the primary transfer medium, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, for example, polymethyl methacrylate fine particles, polystyrene fine particles and the like And polymer fine particles produced by soap-free emulsion polymerization. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

ト ナ ー The toner used in the present invention may contain a charge control agent as needed. As the charge control agent, any known charge control agents can be used. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified) Quaternary ammonium salts), alkyl amides, phosphorus alone or compounds, tungsten alone or compounds, fluorine-based activators, salicylic acid metal salts, and salicylic acid derivative metal salts.

Specifically, bontron 03 of a nigrosine dye, bontron P-51 of a quaternary ammonium salt, bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, and E of a salicylic acid metal complex -84, phenolic condensate E-89 (all manufactured by Orient Chemical Industry Co., Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (all manufactured by Hodogaya Chemical Industry Co., Ltd.), quaternary Ammonium salt copy charge PSYVP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEGVP2036, copycharge NXVPVP434 (all from Hoechst), LRA-901, LR-, a boron complex 147 (all manufactured by Nippon Carlit), copper phthalocyanine, peri Emissions, quinacridone, azo pigments, sulfonate group, carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

カ ー ボ ン Carbon black can be used as the coloring agent in the present invention, and its amount is 1 to 10% by weight, preferably 3 to 7% by weight of the whole toner.

The method for producing the toner of the present invention may be a conventionally known method, in which a binder resin, a wax component, a colorant, and in some cases, a charge control agent and the like are mixed using a mixer or the like, and then heated, extruded, After kneading using a kneading machine such as this, it is cooled and solidified, and this is pulverized by pulverization using a jet mill or the like, and then classified.

(5) The particle diameter of the toner is preferably 5 to 10 μm. When the toner particle size is large, the resolution of an obtained image is deteriorated. On the other hand, if it is too small, the fluidity of the toner is reduced. Table 1 shows an example of the particle size distribution of the toner used in the present invention. The measurement was performed using a Coulter MULTIZER IIe. The aperture diameter is 100 μm. A mixer such as a super mixer or a Henschel mixer is used to add the inorganic powder to the toner.

Further, a conventionally known magnetic substance having an average particle diameter of 30 to 80 μm is used for the carrier core material used in the present invention. Examples thereof include ferromagnetic metals such as iron, cobalt, and nickel, and alloys or compounds such as magnetite, hematite, and ferrite. And the like. By the way, the magnetic properties of the carrier are affected by the magnet roller incorporated in the developing sleeve, and greatly affect the developing properties and the transportability of the developer.

Further, it was found that the use of a silicone resin having a small surface energy as the coating resin for the carrier used in the present invention was extremely effective. As the coating resin used in the examples of the present invention, a general thermosetting silicone resin was used.

{Circle around (4)} When the carrier has a saturation magnetization of 50 to 90 emu / g, particularly in color copying, the uniformity of the image and the reproducibility of the gradation are excellent. When the saturation magnetization exceeds 90 emu / g (for an applied magnetic field of 3000 Oersted), the brush-like spikes formed by the carrier and the toner on the developing sleeve facing the electrostatic latent image on the photoreceptor during development become hard. It is in a tight state, and the gradation and the reproduction of halftone are deteriorated. On the other hand, if it is less than 50 emu / g, it becomes difficult to hold the toner and the carrier on the developing sleeve satisfactorily. The problem that the adhesion and the toner scattering become worse easily occurs.

Further, if the residual magnetization and coercive force of the carrier are too high, good transportability of the developer in the developing device is hindered, and image defects such as blurring and uneven density in a solid image are likely to occur. It will be reduced. Therefore, in order to maintain developability, the residual magnetization is 10 emu / g or less, preferably 5 emu / g or less, more preferably substantially 0, and the coercive force is 40 Oe or less (for an applied magnetic field of 3000 Oe). On the other hand, it is important that it is preferably not more than 30 Oe, more preferably not more than 10 Oe. In consideration of these points, it is preferable to use ferrite as the core material.

微 Furthermore, fine powder is added to the coating layer for the purpose of adjusting the carrier resistance and the like, and the fine powder dispersed in the coating layer preferably has a particle size of about 0.01 to 5.0 μm.

カ ッ プ A coupling agent, particularly a silane coupling agent, can be used for the purpose of further adjusting the carrier charging characteristics and for improving the adhesion between the coating layer and the magnetic particles. For example, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl ) -Γ-aminopropyltrimethoxysilane hydrochloride, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, γ-chloropropyltri Methoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, γ-chloropropylmethyldimethoxy Orchid, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane (all manufactured by Toray Silicon Co., Ltd.), allyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, dimethyldiethoxysilane, 1 , 3-divinyltetramethyldisilazane, methacryloxyethyldimethyl (3-trimethoxysilylpropyl) ammonium chloride (all manufactured by Chisso Corporation) and the like.

Further, a coupling agent, particularly a silane coupling agent, can be used for the purpose of adjusting the carrier charging characteristics and for improving the adhesion between the coating layer and the magnetic particles.
For example, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl ) -Γ-aminopropyltrimethoxysilane hydrochloride, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, γ-chloropropyltri Methoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, γ-chloropropylmethyldimethoxy Orchid, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane (all manufactured by Toray Silicon Co., Ltd.), allyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, dimethyldiethoxysilane, 1 , 3-divinyltetramethyldisilazane, methacryloxyethyldimethyl (3-trimethoxysilylpropyl) ammonium chloride (all manufactured by Chisso Corporation) and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited by the following examples. In the examples, all parts are parts by weight.

[Example 1]
(Production of toner)
Polyester resin (THF insoluble content: 20%) 90 parts Ester wax (particle size: 400 μm) 5 parts Carbon black 5 parts Metal-containing monoazo dye (Pro-Toner Charge, manufactured by Zeneca Corporation)
Control Agent 7) 1 part After these mixtures were sufficiently stirred and mixed in a Henschel mixer, they were heated and melted at a temperature of 140 ° C. for about 30 minutes by a roll mill, and cooled to a thickness of 2.0 mm with a rolling cooling device. The obtained kneaded material was pulverized and classified by a jet mill to obtain a classified toner having an average particle size of 7.0 μm. To 100 parts of the classified product, 0.7 parts of silica fine particles and 0.3 parts of titania fine particles were added and mixed by a Henschel mixer at 1500 rpm to obtain a toner having a volume average particle diameter of 7.5 μm, 5 μm or less and 68% by number of particles. .

[Examples 2 to 9 and Comparative Examples 1 to 9]
Table 1 shows the wax particle diameters, types, and kneading conditions for the toners of Examples 2 to 9 and Comparative Examples 1 to 9 as in Example 1. Except for the conditions described in Table 1, all were the same as Example 1.

Here, the THF insoluble content of the polyester resin was changed from 15% to 30% by changing the crosslinking conditions, and the respective toners were produced by changing the kneading temperature and the rolling and cooling conditions. Table 2 shows T _1/2 , tan δ, THF insoluble content in the toner, and the temperature at which the storage elastic modulus was 1000 Pa in each toner.

(Preparation of carrier)
Silicon resin (20%) 100 parts γ- (2-aminoethyl) aminopropyltrimethoxysilane 1.0 part Carbon black 0.1 part Toluene 60 parts These formulations are dispersed with a homomixer for 20 minutes to form a coating layer forming liquid. Was prepared.
A coating layer was formed on a surface of 1,000 parts of ferrite (volume average particle size: 55 μm, saturation magnetization: 72 emu / g) by using a fluidized bed type coating apparatus, and then fired in an electric furnace to produce a carrier C1.

(Preparation of developer)
Five parts of the toner and 95 parts of the carrier (carrier C1) were stirred and mixed at 50 rpm for 15 minutes using a turbuler mixer to obtain a two-component developer.

[Image evaluation]
The developer D1 prepared as described above was continuously copied on 50,000 sheets (printing rate: 6%) by a remodeling machine of Ricoh's imageio MF2230, and at the start, spent property and image quality at 50,000 sheets were copied. To evaluate. At that time, the fixing control temperature was 185 ° C., and the fixing linear velocity was 100 mm / sec.
Image quality was evaluated in terms of fixability, hot offset resistance, image density, and background stain.

The fixability was evaluated as follows. After shaping the fixing heater temperature to obtain a fixed image, a mending tape (manufactured by 3M) was applied to the fixed image, a certain pressure was applied, and then the film was slowly peeled off. The image density before and after that is measured by a Macbeth reflection densitometer, and the fixing rate is calculated by the following equation. The fixing roller temperature was gradually lowered, and the fixing rate represented by the following equation was obtained.
Fixing rate (%) = image density on tape / image density × 100

With regard to hot offset resistance, 30 sheets of A4 size transfer paper were continuously passed in the longitudinal direction, and after 10 seconds, 30 sheets were continuously passed in a direction in which the transfer paper was rotated by 90 ° C., and the offset phenomenon did not appear. Was evaluated as ○, and when the offset phenomenon appeared, evaluated as ×.

程度 The degree of background contamination was visually ranked. ○ indicates a pass level, Δ indicates an acceptable level, and × indicates an unacceptable level.

Evaluation of image density is measured by Macbeth reflection densitometer.

Table 3 shows the above evaluation results. FIG. 1 shows a relationship diagram between T _1/2 and tan δ.

　比較例８においては定着不良の為、画像評価は出来なかった。

In Comparative Example 8, image evaluation could not be performed due to poor fixing.

FIG. 4 is an explanatory diagram illustrating a relationship between T _1/2 and tan δ required for toner characteristic measurement of the present invention. It is an explanatory view of a flow tester outflow curve of a flow tester for measurement of the present invention.

Claims (6)

A toner used in a fixing method in which a fixing roller is heated by using a heater and is fixed by a pressing force with a pressure roller and heat from the fixing roller, the toner contains at least wax, a binder resin, and carbon black as a colorant. When the 1/2 outflow temperature T _1/2 (° C.) of the toner by the elevated flow tester is 160 ° C. or less, T _{1/2 of} the toner, dielectric loss tan δ, and the fixing control temperature of the fixing device are determined. A toner for electrostatic charge development, wherein the relationship with T (° C.) satisfies Expressions (1) and (2).
T ≦ A × T _1/2 + B × tan δ−105.0 ・ ・ ・ ・ ・ (1)
4.0 × 10 ⁻³ ≦ tan δ ≦ 6.5 × 10 ⁻³ (2)
A = 1.9, B = 3.8 × 10 ³ The binder resin used in the toner is at least a polyester resin, and the polyester resin contains 10 to 30% by weight of a THF-insoluble component, and 4 to 12% by weight of a THF-insoluble component in the toner. Item 3. The toner for developing an electrostatic image according to Item 1. ^{3. The} toner according to claim 2, wherein the temperature at which the storage elastic modulus G 'of the toner reaches 10 ³ Pa is 180 ° C. or higher. The wax used in the toner comprises at least one of carnauba wax, rice wax, and ester wax, and the raw material particle size of the wax is 100 to 600 µm. The toner for developing an electrostatic image according to the above. A two-component developer comprising the toner according to any one of claims 1 to 4 and a carrier. 2. A process cartridge which integrally supports a photosensitive member and at least one unit selected from a charging unit, a developing unit, and a cleaning unit and is detachable from an image forming apparatus main body, wherein the developer used for the developing unit is A process cartridge comprising a one-component developer comprising the toner according to any one of claims 1 to 4, or a two-component developer according to claim 5.

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