JP2002365834A - Electrostatic latent image developing toner, image forming method and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner excellent in fluidity, not causing image stain due to scattering even under severe service conditions, giving stable images because the lowering of halftone uniformity due to a buried additive is hardly caused, giving sharp images with few diffused fine dots because of a uniform electric charge distribution, having small environmental dependence and not causing trouble such as black spots to an image and free of the lowering of its fluidity and a change in its electrostatic chargeability, thereby ensuring high image density and no fog even when used in an image forming method and an image forming apparatus with an incorporated toner recycling system. SOLUTION: The electrostatic latent image developing toner obtained by adding an additive to colored particles consisting at least of a bonding resin and a colorant is characterized in that the additive is inorganic particles having a shape formed by bonding 6 to 500 fine particles in a chain or branched shape, wherein the bonds are covalent bonds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing toner used in a copying machine, a printer, and the like, and an image forming method and an image forming apparatus using the same.

[0002]

2. Description of the Related Art An image forming method utilizing an electrostatic latent image developing method represented by an electrophotographic method is disclosed in US Pat.
Nos. 7,691 and 2,357,809. These form an electrostatic latent image on the surface of the photoreceptor and develop the electrostatic latent image into a toner image with a dry developer composed of at least a colored fine powder (toner). This is a method of forming a final image by a transfer step of transferring a toner image and then a fixing step of fixing the toner image on a recording material by heating or pressing.

In order for a final image to be formed with good image quality over a long period of time, a toner for developing an electrostatic latent image (also simply referred to as toner) must have high fluidity and maintain stable chargeability. is necessary. As a technique for improving the fluidity of a toner, it is known to add and mix a fluidizing agent such as silica fine particles as an external additive to at least colored particles containing a coloring agent in a binder resin.

As described above, in the developing step, the electrostatic latent image is developed to form a toner image. However, not all the toner forming the toner image is transferred to the recording material. Part of the toner remains on the photoconductor.

Conventionally, the residual toner has been collected and discarded by a cleaning device. In recent years, however, the recovered toner has been returned to the developing device by a toner conveying screw or the like from the viewpoint of economy and environmental safety. Attention has been paid to an image forming apparatus employing a so-called toner recycling system which is used again as a developing toner.

However, when an image is formed by an image forming apparatus employing a toner recycling system using a toner containing a fluidizing agent having a small particle diameter as in the conventional case, the toner is excessively large due to a toner conveying screw or the like. Subject to physical compression forces. For this reason, a fluidizing agent (external additive) to be present on the surface of the toner particles is embedded in the toner particles, and the fluidity of the toner gradually decreases, and the charge amount of the toner changes. And the image density is reduced.

In order to suppress the above-mentioned phenomenon in which the fluidizing agent of the toner is embedded in the toner particles and the fluidity of the toner is reduced, for example, Japanese Patent Application Laid-Open Nos.
Techniques described in Japanese Patent Application Laid-Open Nos. 0-104869 and 10-198066 are proposed. Japanese Patent Application Laid-Open No. 2000-298372 discloses a technique in which a large particle size external additive and a small particle size external additive are used together and applied to a one-component developer.

[0008] However, at present, none of the techniques has been a sufficient solution to the problem. In particular, recently, in order to improve image quality, a so-called polymerization toner using resin particles obtained by polymerizing a polymerizable monomer in an aqueous medium has been put to practical use. In the case of this polymerization method toner, since the particle surface is smooth and has few irregularities and the contact surface with the photoreceptor surface is large, it is easy to cause problems in cleaning properties, and the role of the external additive is so important, and the external additive is buried. It is expected that problems will arise due to such factors.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object the object of the present invention is that it has excellent fluidity and prevents image stains due to scattering of toner granules and toner aggregates even under severe use conditions. No, stable image with less decrease in halftone homogeneity due to toner external additive burial, uniform charge distribution, sharp image with less fine dot dust, less environmental dependency, electrostatic image development To provide a toner for use.

Further, even when the present invention is used in an image forming method or apparatus incorporating a toner recycling system, no failure such as black spots occurs in the image, and there is no decrease in toner fluidity or chargeability. Therefore, the image density is high. An object of the present invention is to provide a toner for developing an electrostatic image without fogging, an image forming method, and an image forming apparatus.

[0011]

Means for Solving the Problems As a result of extensive studies by the inventors of the present invention, the external additive has a shape in which fine particles having an outer shape of 6 to 500 are combined in a chain or a branch. It has been found that the object of the present invention can be achieved by using inorganic particles having a covalent bond.

The inorganic particles have a particle diameter of 5 nm.
Not less than 100 nm and more preferably not less than 8 nm and 6
A plurality of fine particles having a particle diameter of 30 nm
Not less than 800 nm and more preferably not less than 80 nm and 5
Those having a shape of being linked in a chain or branch of not more than 00 nm are preferred.

That is, it has been found that the object of the present invention can be achieved by adopting any of the following constitutions.

[1] In a toner for developing an electrostatic latent image obtained by adding an external additive to colored particles comprising at least a binder resin and a colorant, the external additive is formed by chaining fine particles having an outer diameter of 6 to 500. A toner for developing an electrostatic latent image, characterized in that the toner is an inorganic particle having a shape linked in a shape or a branch, and the bond is a covalent bond.

[2] When the inorganic particles are combined with fine particles having a particle size of 5 nm or more and 100 nm or less,
The toner for developing an electrostatic latent image according to [1], which has a particle diameter of 0 nm or less and is subjected to a hydrophobic treatment.

[3] When the inorganic particles are combined with fine particles having a particle size of 8 nm or more and 60 nm or less,
The toner for developing an electrostatic latent image according to [2], having a particle size of not more than nm.

[4] The colored particles are toners in which the ratio of particles having no corners is 50% by number or more and the number variation coefficient in the number particle size distribution is 27% or less. [3] The toner for developing an electrostatic latent image according to any one of [3].

[5] The colored particles have a shape factor of 1.
Any one of [1] to [4], wherein the ratio of particles in the range of 2 to 1.6 is at least 65% by number and the variation coefficient of the shape coefficient is 16% or less. Item 7. The toner for developing an electrostatic latent image according to Item 1.

[6] The colored particles are resin particles obtained by polymerizing at least a polymerizable monomer in an aqueous medium, wherein the resin particles are any one of [1] to [5].
Item 7. The toner for developing an electrostatic latent image according to Item 1.

[7] The electrostatic latent element according to any one of [1] to [6], wherein the colored particles are obtained by aggregating and fusing at least resin particles in an aqueous medium. Image developing toner.

[8] BET specific surface area of 1.1 to 4.0
any of [1] to [7], characterized in that m ² / g, the surface abundance of silicon atoms measured by ESCA is 6 to 12 area%, and the abundance of carbon atoms is 50 to 75 area%. Or 1
Item 7. The toner for developing an electrostatic latent image according to Item 1.

[0022]

[9] An image forming method employing a toner recycling system, wherein the toner for developing an electrostatic latent image according to any one of [1] to [8] is used.

[10] An image forming method using a non-magnetic one-component developing method, wherein the toner for developing an electrostatic latent image according to any one of [1] to [8] is used. .

[11] An image forming apparatus employing a toner recycling system, wherein the toner for developing an electrostatic latent image according to any one of [1] to [8] is used.

[12] An image forming apparatus employing a non-magnetic one-component developing method, wherein the toner for developing an electrostatic latent image according to any one of [1] to [8] is used. .

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The constitutional requirements and embodiments of the present invention will be further described.

[Inorganic Particles] The inorganic particles are silica or a metal oxide such as alumina or titanium oxide in terms of composition, and have a fluidizing effect when mixed with colored particles that serve as a toner base. .

The external additive of the present invention is characterized in that its outer shape is 6 to
It has a shape in which 500 fine particles are combined in a chain or branch, and the fine particles are firmly bound by a covalent bond. Therefore, those connected only by electrostatic aggregation, ionic bonding, van der Waals force, surface adhesion force, and the like are not included in the scope of the present invention.

Further, the fine particles having a shape in which the fine particles are bonded in a chain or a branch are typically those having a bonding shape as shown in FIG. 1, and FIG. (B) is a branched bond. Of course,
In the case where the number of fine particles to be bonded is large, the fine particles may be mixed or multiply connected. The shape as a whole may have a mesh shape as in (c), an annular shape as in (d), a crown shape as in (e), etc. It has a shape joined in a branch shape.

These shapes can be confirmed by photographing with an electron microscope or the like. In this case, the thickness of the connecting portion of the fine particles and that of the other portion do not change so much, and there are some which look almost like a rod as a whole.

The fine particles typically have a spherical shape or an elliptical shape, but may have a considerably deformed shape.
Further, the particle diameter is 5 nm or more and 100 nm or less, more preferably 8 nm or more and 60 nm or less, and a plurality of fine particles are combined to form inorganic particles having a particle diameter of 30 nm or more and 800 nm or less, more preferably 80 nm or more and 500 nm or less. That's what we've already said.

In the present invention, the particle diameter of the inorganic particles is measured from a photograph enlarged and photographed with a transmission electron microscope.

By using these non-spherical inorganic particles, burying of the inorganic particles in the toner is prevented, and the inorganic particles are not separated from the toner, so that the fluidity stability and the cleaning property are remarkably improved.

In particular, the inorganic particles are firmly held in the base toner for the polymerization method toner having many spherical or curved surfaces. That is, the configuration of the inorganic particles in which the fine particles are combined in a chain or a branch shape can prevent burying in the base while maintaining high fluidity. In addition, the extension of the prior art has an effect that cannot be expected in that the separation from the toner can be prevented, and thus the performance has greatly increased.

In view of the above, the inorganic particles in which the fine particles of the present invention are bound in a chain or branch are preferably those having a hydrophobicity of 30 nm or more and 800 nm or less, and more preferably 80 nm or more and 500 nm or less. It is better to use Among them, especially 100 nm or more 2
Those having a thickness of 00 nm or less are good.

When the fine particles forming the chain-like or branched inorganic particles of the present invention are too small, burying in the toner matrix is promoted, and when the particle diameter is large, detachment from the toner is large. Therefore, those having a thickness of preferably 5 nm to 100 nm, more preferably 8 nm to 60 nm are used. Among them, those having a thickness of 18 nm or more and 40 nm or less are particularly preferable.

The non-spherical inorganic particles according to the present invention can be obtained by various methods, and in the present invention, those obtained by any method can be used in the present invention.

Hereinafter, a specific method for producing the inorganic particles of the present invention will be described. For example, the following (a), (b),
There is a manufacturing method through steps (c) and (d).

(A) Water-soluble in a colloidal aqueous solution of activated silicic acid or an acidic silica sol having an average particle diameter of 3 to 8 nm containing 0.5 to 10% by mass as SiO ₂ and having a pH of 2 to 6 of an aqueous solution containing either alone or in combination with bivalent or trivalent metal salts, relative to the SiO ₂ in the aqueous colloidal solution or acidic silica sol of the active silicic acid, metal oxides (for divalent metal salts MO and M ₂ O _{3 in} the case of a salt of a trivalent metal, where M represents a divalent or trivalent metal atom and O represents an oxygen atom.
And (b) mixing the mixture (a) obtained in the step (a) with an average particle diameter of 10 to 120.
The ratio A / B (mass ratio) of the silica content (A) derived from the acidic spherical silica sol to the silica content (B) derived from the mixed solution (a) is 5 to 5 nm. 100, and the total silica content (A + B) of the mixture (b) obtained by mixing the acidic spherical silica sol and the mixture (a) is SiO 2 in the mixture (b).
₍₂₎ a step of adding and mixing an amount to give a concentration of 5 to 40% by mass,
(C) a step of adding an alkali metal hydroxide, a water-soluble organic base or a water-soluble silicate thereof to the mixed solution (b) obtained in the step (b) so as to have a pH of 7 to 11, and mixing. (D) heating the mixture (c) obtained in the step (c) at 100 to 200 ° C. for 0.5 to 50 hours.

Alternatively, the following production method may be used. (A) having 1 to 6% by mass as SiO ₂ and p
An aqueous solution containing a water-soluble calcium salt, a magnesium salt or a mixture thereof is added to a colloidal aqueous solution of activated silicic acid in which H is 2 to 5 with respect to the SiO _{2 of the} activated silicic acid.
aO, MgO or both as mass ratio of 1500 to 8
A step of adding and mixing in an amount of 500 ppm, (b)
(A) adding an alkali metal hydroxide, a water-soluble organic base or a water-soluble silicate thereof to the aqueous solution obtained in the step (a);
O ₂ / M ₂ O (where SiO ₂ represents the content of the silica content derived from the active silicic acid and the silica content of the silicate, and M represents the alkali metal atom or organic base molecule) molar ratio of 20 (C) a part or all of the mixture obtained in the step (b) is heated to 60 ° C. or more to form a heel solution,
A part of the mixture obtained in the step (b) or the mixture separately prepared in the step (b) is used as a feed liquid,
The feed solution is added to the heel solution, and the water is evaporated during the addition so that the SiO ₂ concentration is 6 to 3%.
Concentration to 0% by mass.

Also, commercially available non-spherical colloidal silica can be suitably used. Examples include Nissan Chemical's Snowtex UP series (including acid type and cation modified type) or Snowtex PS
Series (including acidic type, cationic modified type, etc.).

[Small particle size external additive that may be used in combination] In addition to the pearl necklace-like silica, small particle size silica particles may be used in combination to further impart fluidity to the toner. It is preferable to add 0.1 to 0.8 parts by mass based on 100 parts by mass of the toner (without adding external additives).

Examples of commercially available silica fine powder include those commercially available under the following trade names.

AEROSIL13 from Aerosil Japan
0, 200, 200V, 200CF, 200FAD, 3
00, 300 CF, 380, or CA-
O-SilM-5, MS-7D, MS-75D, H-
5, HS-5, EH-5, or PACKER-CHF
MIEGMBH Wacker HDK N20, S
13, V15, N20, T30, T40 and the like.

The following are examples of the silica subjected to the hydrophobic treatment. Clariant's HDK H
2000, 2000/4, 3004, 2050EP, H
VK21 or Nippon Aerosil R972, R974,
RX200, RY200, R202, R805, R81
There are 2 etc.

As a material having a slightly larger particle size, AERSIL OX50 and AERSIL5 manufactured by Nippon Aerosil Co., Ltd.
0, TT600, MOX80, and MOX170. Examples of hydrated silica include the following. Cabot TS630, Kao NA-50
H, Nippon Aerosil RY-50, NY-50, NA
X-50, RX-50, RM-50 and the like.

The following are specific examples of the titanium oxide fine particles. P-25 (made by Degussa); IT-
S, IT-PA, IT-PB (all manufactured by Idemitsu Kosan Co., Ltd.); R-820, R-830, R-680, CR-5
0, CR-60, A-100, A-220 (all manufactured by Ishihara Sangyo Co., Ltd.); MT-100SA, MT-150W, M
T-500B, MT-600B (both manufactured by Teika)
Etc.

Examples of the titanium oxide fine particles subjected to the hydrophobic treatment are as follows. STT-30
A, STT-30AS, STT-30S (all manufactured by Titanium Industry Co., Ltd.); T-805 (manufactured by Nippon Aerosil Co., Ltd.); T
TO-51 (manufactured by Ishihara Sangyo); TAF-1500S (manufactured by Fuji Titanium); MT-100S, MT-100T
(Manufactured by Teica).

The number average particle diameter is 0.015 to 0.070
It is preferable to add 0.1 to 1.0 parts by mass of the titanium oxide having a particle size of μm with respect to 100 parts by mass of the toner (without adding an external additive). More preferably, it is 0.2 to 0.8 parts by mass.

Other commercially available titanium oxide particles include:
For example, there are products marketed under the following trade names. Examples of TTO-51 (A) and TTO-51 (B) (all manufactured by Ishihara Sangyo Co., Ltd.); TAF-620 (manufactured by Fuji Titanium Industry Co., Ltd.) There is something like that. STT-60J
(Manufactured by Titanium Industry Co., Ltd.), JA-1, JA-3, JA-4,
JA-5 (all manufactured by Teica); TAF-520, T
AF-520AS, TAF-520K (both manufactured by Fuji Titanium Industry Co., Ltd.) and the like.

The titanium oxide fine particles used as the external additive include those produced by a sulfuric acid method and a chlorine method. Further, as the crystal type, there are rutile, anatase, rutile, a mixed crystal of anatase, amorphous, and a mixed type thereof, and all of them can be used. From the viewpoint of ensuring fluidity and reducing the environmental dependence of charging, the ratio of rutile-type titanium oxide to anatase titanium oxide is 2:98 to 4 in mass ratio.
Titanium oxide in the range of 5:55 is preferably used. Further, it is preferable that the particle surface of the rutile-containing / anatase mixed titanium oxide is coated with a layer containing one or more of aluminum, silicon, titanium, zirconium and tin. That is, it is preferable that the surface of the particles before the treatment with the silane coupling agent is coated with a layer containing the predetermined element.

The reason why the layer is coated before the silane coupling agent treatment is performed is to adjust the charging property and the resistance. The treatment amount of the element is preferably 3 to 20% by mass. 3
If the amount is less than 20% by mass, it is difficult to obtain the effect of adjusting the charge.
If it exceeds 0% by mass, coalescence of the particles occurs, which is not preferable.

The coupling agent preferably used includes silane coupling agents such as methyltrimethoxysilane, methyltriethoxysilane, octyltrimethoxysilane and the like.

Examples of the lubricant which can be used as an external additive include metal salts of higher fatty acids. Specific examples of such metal salts of higher fatty acids include metal stearate salts such as zinc stearate, aluminum stearate, copper stearate, magnesium stearate, and calcium stearate; zinc oleate, manganese oleate, iron oleate, and olein. Metal oleate such as copper phosphate and magnesium oleate; metal palmitate such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; metal linoleate such as zinc linoleate and calcium linoleate; ricinol And metal salts of ricinoleic acid such as zinc acid and calcium ricinoleate.

The addition amount of the external additive is preferably about 0.1 to 5% by mass based on the toner.

[Step of Adding External Additive] This step is a step of adding the external additive to the dried toner particles.

Examples of an apparatus used for adding the external additive include a turbular mixer, a Henschel mixer,
Various known mixing devices such as a Nauta mixer and a V-type mixer can be used.

In the present invention, the surface of the treated layer treated with the silane coupling agent may be further coated with a coupling agent and / or silicone oil.

That is, after the silane coupling agent is treated in an aqueous medium, the silane coupling agent or an organosilicon compound such as silicone oil is treated in the gas phase in order to improve the hydrophobicity and adjust the charge amount. Can be.

As the silane coupling agent that can be used in this case, besides those described above, fluorosilane, aminosilane, polydimethylsiloxane, methylhydrogenpolysiloxane and the like can be used.

When the treatment is performed in the gas phase, the treatment amount is 1 to 20% by mass, particularly 3 to 1% by mass, based on 100% by mass of the obtained fine powder.
Preferably, the treatment is performed at 5% by mass. If the treatment amount is less than 1% by mass, the effect cannot be obtained, and if it exceeds 20% by mass, the specific surface area is undesirably low.

[Specific Surface Area and Surface Abundance of Silicon Atoms Measured by ESCA] The toner of the present invention preferably has a BET specific surface area of 1.1 to 4.0 m ² / g. Especially preferably, it is 1.1-1.9 m < ² > / g.

The BET specific surface area was measured using an automatic specific surface area measuring device GEMINI 2375 (manufactured by Shimadzu Corporation).
It was measured by the ET one point method.

The surface abundance of silicon atoms measured by ESCA was 6 to 12% by area, and the abundance of carbon atoms was 50 to 7%.
Preferably, it is 5 area%.

The measurement by ESCA was carried out by using Shimadzu E
Using SCA-1000, the area ratio occupied by each element was determined from the relative intensity ratio of carbon, oxygen, and silicon.

If the BET specific surface area is too small, the fluidity is poor, and if the BET specific surface area is too large, the variation in the charge amount due to the burying of the external additive tends to increase. If the surface abundance of silicon atoms measured by ESCA is in the range of 6 to 12 area% and the abundance of carbon atoms is in the range of 50 to 75 area%, moisture absorption under high temperature and high humidity is small, and low Is small, and a stable image can be obtained.

[Cleaning Condition] The cleaning system used in the present invention is preferably a cleaning blade system.

The cleaning blade is preferably an elastic rubber blade. The physical properties of the cleaning blade can be controlled at the same time by controlling the rubber hardness and the rebound resilience, so that the torque fluctuation during cleaning can be controlled to be small, and the reversal of the blade can be suppressed more effectively. If the JISA hardness of the blade at 25 ± 5 ° C. is smaller than 65, the blade is likely to be inverted, and if it is larger than 80, the cleaning performance is reduced. When the rebound resilience exceeds 80, reversal of the blade tends to occur, and when the rebound resilience is 20 or less, the cleaning performance deteriorates. More preferable rebound resilience is 20 or more and 80 or less. The Young's modulus is preferably in the range of 294 to 588 N / cm ² (both JISA hardness and rebound resilience are JISK).
It is measured based on the vulcanized rubber physical test method 6301. Numerical values of rebound resilience indicate%).

As the material of the elastic rubber blade used for the cleaning blade, urethane rubber, silicone rubber, fluorine rubber, chloropyrene rubber, butadiene rubber and the like are known. Of these, urethane rubber is other rubber. It is particularly preferred in that it has excellent wear characteristics as compared with For example, urethane rubber obtained by reacting and curing a polycaprolactone ester and a polyisocyanate described in JP-A-59-30574 is preferable.

In the present invention, the method of fixing the elastic rubber blade to the support member is preferably such that the elastic rubber blade is substantially held by the support member on the photosensitive member contact surface side. By employing such a holding method, torque fluctuation of the cleaning blade can be stabilized.

[Electrophotographic Photoreceptor] An organic photoreceptor is most often used for the electrophotographic photoreceptor (also simply referred to as a photoreceptor) used in the present invention.

In the present invention, the organic electrophotographic photoreceptor (organic photoreceptor) is constituted such that an organic compound has at least one of a charge generation function and a charge transport function which are indispensable for the constitution of the electrophotographic photoreceptor. Means an electrophotographic photosensitive member. For example, all known organic electrophotographic photoreceptors, such as a photoreceptor composed of a known organic charge generating substance or an organic charge transporting substance, and a photoreceptor composed of a polymer complex having a charge generation function and a charge transporting function, are included.

Hereinafter, the constitution of the organic photoreceptor used in the present invention will be described. (Conductive Support) As the conductive support used in the photoreceptor of the present invention, either a sheet-like or a cylindrical support may be used, but in order to design an image forming apparatus compactly, a cylindrical conductive support is used. The body is preferred.

The cylindrical conductive support of the present invention means a cylindrical support necessary for forming an image endlessly by rotating, and has a roundness of 0.1 mm or less and a runout of 0.1 mm or less. Are preferred. Exceeding the ranges of the roundness and the shake make it difficult to form a good image.

As the conductive material, a metal drum such as aluminum or nickel, a plastic drum on which aluminum, tin oxide, indium oxide or the like is deposited, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ω · cm or less at room temperature.

The conductive support used in the present invention may have a surface on which a sealed alumite film is formed. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, and sulfamic acid, but anodizing treatment in sulfuric acid gives the most preferable result. In the case of the anodic oxidation treatment in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average thickness of the anodic oxide coating is usually 2
It is preferably 0 μm or less, particularly preferably 10 μm or less.

(Intermediate Layer) In the present invention, an intermediate layer is provided between the conductive support and the photosensitive layer in order to improve the adhesion between the conductive support and the photosensitive layer or to prevent charge injection from the support. A layer (including an undercoat layer) can also be provided. As the material of the intermediate layer, polyamide resin, vinyl chloride resin,
Examples include vinyl acetate resins and copolymer resins containing two or more of the repeating units of these resins. Among these undercoating resins, a polyamide resin is preferable as a resin capable of reducing an increase in residual potential due to repeated use.
The thickness of the intermediate layer using these resins is 0.01 to
0.5 μm is preferred.

The intermediate layer most preferably used in the present invention is an intermediate layer using a curable metal resin obtained by thermally curing an organic metal compound such as a silane coupling agent and a titanium coupling agent. The thickness of the intermediate layer using a curable metal resin is preferably 0.1 to 2 μm.

(Photosensitive Layer) The photosensitive layer of the photoreceptor of the present invention may have a single-layer structure in which the intermediate layer has a charge generation function and a charge transport function in one layer, but is more preferable. It is preferable to adopt a configuration in which the function of the photosensitive layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a configuration in which functions are separated, an increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the photoreceptor for negative charging, a charge generation layer (CGL) is provided on the intermediate layer, and a charge transport layer (C
It is preferable to adopt the configuration of (TL). In the case of a positively charged photoreceptor, the order of the layer configuration is opposite to that of the negatively charged photoreceptor. The most preferred photosensitive layer structure of the present invention is a negatively charged photosensitive member having the function-separated structure.

The structure of the photosensitive layer of the function-separated negatively charged photosensitive member will be described below. (Charge generation layer) The charge generation layer has a charge generation material (CGM)
It contains. As other substances, a binder resin and other additives may be contained as necessary.

As the charge generating substance (CGM), a known charge generating substance (CGM) can be used. For example, phthalocyanine pigments, azo pigments, perylene pigments, azurenium pigments, and the like can be used. Among them, CGM that can minimize the increase in residual potential due to repeated use
Has a steric and potential structure capable of forming a stable aggregation structure among a plurality of molecules, and specifically includes CGM of a phthalocyanine pigment and a perylene pigment having a specific crystal structure. For example, Bragg angle 2θ for Cu-Kα ray
CGM such as titanyl phthalocyanine having a maximum peak at 27.2 ° and benzimidazole perylene having a maximum peak at 2θ of 12.4 have almost no deterioration with repeated use and can reduce the increase in residual potential.

When a binder is used as a dispersion medium of CGM in the charge generation layer, a known resin can be used as the binder, but the most preferred resin is a formal resin, a butyral resin, a silicone resin, a silicone-modified butyral resin, a phenoxy resin. Resins. The ratio between the binder resin and the charge generating substance is preferably from 20 to 600 parts by mass per 100 parts by mass of the binder resin. By using these resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably from 0.01 μm to 2 μm.

(Charge Transport Layer) The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing the CTM and forming a film. As other substances, additives such as antioxidants may be contained as necessary.

As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, butadiene compounds and the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, the CTM that can minimize the increase in residual potential due to repeated use has a high mobility and a characteristic in which the ionization potential difference with the CGM to be combined is 0.5 (eV) or less, and is preferably 0. .25 (eV) or less.

The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, and alkyd. Resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, poly-
A high-molecular organic semiconductor such as N-vinylcarbazole may be used.

The most preferred binder for these CTLs is a polycarbonate resin. Polycarbonate resins are most preferred for improving the dispersibility and electrophotographic properties of CTM. The ratio of the binder resin to the charge transporting material is preferably from 10 to 200 parts by mass per 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably from 10 to 40 μm.

(Protective Layer) As the protective layer of the photoreceptor, various resin layers can be provided. In particular, by providing a crosslinked resin layer, the organic photoreceptor of the present invention having high mechanical strength can be obtained.

Solvents or dispersion media used for forming layers such as the intermediate layer, photosensitive layer and protective layer of the present invention include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N- Dimethylformamide, acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,
2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolan, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl Cellosolve and the like. Although the present invention is not limited to these, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone and the like are preferably used. In addition, these solvents can be used alone or as a mixed solvent of two or more kinds.

Next, as a coating method for producing the organic electrophotographic photoreceptor of the present invention, coating methods such as dip coating, spray coating, and circular amount control type coating are used.
The coating process on the upper layer side of the photosensitive layer is performed by spray coating or by a circular amount control type (a typical example is a circular slide hopper type) in order to minimize dissolution of the lower layer film and achieve uniform coating. It is preferable to use It is most preferable that the protective layer of the present invention uses the above-mentioned circular amount control type coating processing method. The circular amount control type coating is described in detail in, for example, JP-A-58-189061.

Next, the toner used in the present invention will be described. [Toner Production Method] There is no particular limitation, and any known method, for example, a so-called pulverization method or polymerization method can be used.

However, preferably, the toner of the present invention is prepared by suspension polymerization or emulsion polymerization of a monomer in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added, or by miniemulsion polymerization. It is preferable to prepare fine resin particles by using the method described above, and then add a coagulant such as an organic solvent and salts to aggregate and fuse the resin particles.

(Suspension Polymerization Method) A charge controlling resin is dissolved in a polymerizable monomer, and various constituent materials such as a colorant, a releasing agent as needed, and a polymerization initiator are added thereto. Various constituent materials are dissolved or dispersed in the polymerizable monomer using a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer into oil droplets of a desired size as a toner using a homomixer, a homogenizer, or the like. Thereafter, the mixture is transferred to a reaction device (stirring device) having a stirring mechanism, and heated to cause the polymerization reaction to proceed. After completion of the reaction, the toner of the present invention is prepared by removing the dispersion stabilizer, filtering, washing and drying. The “aqueous medium” in the present invention refers to a medium containing at least 50% by mass of water.

(Emulsion Polymerization Method) As a method for producing the toner of the present invention, resin particles are salted out, agglomerated and dispersed in an aqueous medium.
A method of preparing by fusing can also be mentioned. This method is not particularly limited, for example,
JP-A-5-265252 and JP-A-6-32994
No. 7, JP-A-9-15904. That is, a method of salting out, aggregating, and fusing a plurality of fine particles composed of a resin and a coloring agent, or a dispersion particle of a constituent material such as a resin particle and a coloring agent, and particularly dispersing these in water using an emulsifier. After that, a coagulant having a critical coagulation concentration or more is added and salted out, and at the same time, the formed polymer itself is heated and fused at a temperature of the glass transition temperature or more to gradually grow the particle size while forming fused particles. When the target particle size is reached, add a large amount of water to stop the particle size growth, further heat and stir to smooth the particle surface to control the shape, and heat the particles in a fluid state while keeping the particles wet. By drying, the toner of the present invention can be formed. Here, a solvent such as alcohol which is infinitely soluble in water may be added together with the coagulant.

(Specific Production Method) Next, a specific production example by a polymerization method will be described.

An example in which a release agent is contained in a region other than the outermost layer of the composite resin particles obtained by the multi-stage polymerization method will be described.

The toner manufacturing process mainly includes the following steps. 1: Area where the release agent is other than the outermost layer (center or middle layer)
Multistage polymerization step (I) for obtaining composite resin particles contained in (2): salting out / fusion step (II) of salting out / fusing composite resin particles and colorant particles to obtain colored particles : Filtration / washing step of filtering the colored particles from the dispersion of the colored particles to remove a surfactant or the like from the colored particles 4: Drying step of drying the washed colored particles 5: Drying of the colored particles To form a toner by adding an external additive.

Hereinafter, each step will be described in detail. Multi-stage polymerization step (I) The multi-stage polymerization step (I) is a step of producing composite resin particles by a multi-stage polymerization method in which a coating layer made of a monomer polymer is formed on the surface of the resin particles.

In the present invention, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoints of production stability and crushing strength of the obtained toner.

Hereinafter, two-stage polymerization and three-stage polymerization, which are typical examples of the multi-stage polymerization, will be described.

<Two-Step Polymerization Method> The two-step polymerization method comprises a central portion (core) formed of a high molecular weight resin containing a release agent and an outer layer (shell) formed of a low molecular weight resin. This is a method for producing composite resin particles.

The method will be described in detail. First, a release agent is dissolved in a monomer K to prepare a monomer solution, and the monomer solution is added to an aqueous medium (for example, an aqueous solution of a surfactant). After oil droplets are dispersed in the system, this system is subjected to polymerization treatment (first stage polymerization).
By doing so, a dispersion of high molecular weight resin particles containing a release agent is prepared.

Next, a polymerization initiator and a monomer K for obtaining a low molecular weight resin are added to the dispersion of the resin particles.
Polymerization treatment of monomer K in the presence of resin particles (second stage polymerization)
Is carried out to form a coating layer made of a low molecular weight resin (polymer of monomer K) on the surface of the resin particles.

<Three-Step Polymerization Method> The three-step polymerization method comprises a central part (nucleus) formed of a high molecular weight resin, an intermediate layer containing a release agent, and an outer layer (shell) formed of a low molecular weight resin. This is a method for producing composite resin particles.

The method will be described in detail. First, a dispersion of resin particles obtained by a polymerization treatment (first-stage polymerization) according to a conventional method is added to an aqueous medium (for example, an aqueous solution of a surfactant). Along with the addition, the monomer solution obtained by dissolving the release agent in the monomer M is dispersed in the aqueous medium in oil droplets, and then the system is subjected to a polymerization treatment (second stage polymerization).
A coating layer (intermediate layer) made of a resin (polymer of monomer M) containing a release agent is formed on the surface of the resin particles (core particles) to form composite resin particles (high molecular weight resin-intermediate molecular weight resin). )
A dispersion of is prepared.

Next, a polymerization initiator and a monomer K for obtaining a low molecular weight resin are added to the obtained dispersion of the composite resin particles, and the monomer K is subjected to a polymerization treatment in the presence of the composite resin particles. By performing (third stage polymerization), a coating layer made of a low molecular weight resin (polymer of monomer K) is formed on the surfaces of the composite resin particles. In the above method, by incorporating the second-stage polymerization, the release agent can be finely and uniformly dispersed, which is preferable.

One feature of the method for producing a toner according to the present invention is to polymerize a polymerizable monomer in an aqueous medium. That is, when forming resin particles (core particles) or a coating layer (intermediate layer) containing a release agent, the release agent is dissolved in a monomer, and the resulting monomer solution is oiled in an aqueous medium. In this method, latex particles are obtained by dispersing droplets, adding a polymerization initiator to the system, and performing a polymerization treatment.

The aqueous medium referred to in the present invention is water 50 to 10
A medium comprising 0% by mass and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include, for example, methanol, ethanol, isopropanol, butanol,
Acetone, methyl ethyl ketone, tetrahydrofuran and the like can be exemplified, and an alcohol-based organic solvent which does not dissolve the obtained resin is preferable.

According to the method of mechanically forming oil droplets (mini-emulsion method), unlike the usual emulsion polymerization method, the release agent dissolved in the oil phase does not desorb, A sufficient amount of release agent can be introduced into the resin particles or the coating layer to be formed.

Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited, and for example, a stirrer “CLEARMIX” equipped with a high-speed rotating rotor (M -Technic), ultrasonic disperser, mechanical homogenizer,
Mentongorin and a pressure-type homogenizer can be used. In addition, the dispersion particle diameter is 10 to
1000 nm, preferably 50 to 1000 nm,
More preferably, it is 30 to 300 nm.

As other polymerization methods for forming the resin particles containing the release agent or the coating layer, emulsion polymerization methods,
Known methods such as a suspension polymerization method and a seed polymerization method can also be employed. In addition, these polymerization methods are resin particles (core particles) or coating layers constituting the composite resin particles,
It can also be employed to obtain one that does not contain a release agent.

The particle diameter of the composite resin particles obtained in the polymerization step (I) is determined by using an electrophoretic light scattering photometer “ELS-80”.
It is preferable that the mass average particle diameter measured using “0” (manufactured by Otsuka Electronics Co., Ltd.) is in the range of 10 to 1000 nm.

Further, the glass transition temperature (T
g) is preferably in the range of 48 to 74 ° C, more preferably 52 to 64 ° C.

The softening point of the composite resin particles is 95-14.
It is preferably in the range of 0 ° C. Salting-out / fusion step (II) The salting-out / fusion step (II) is carried out in the multi-stage polymerization step (I).
Salting out the composite resin particles and the colorant particles obtained by
This is a step of obtaining amorphous (non-spherical) toner particles by fusing (simultaneously salting out and fusing).

The salting out / fusion in the present invention means that salting out (aggregation of particles) and fusion (loss of interface between particles) occur simultaneously, or salting out and fusion occur simultaneously. Act. In order to simultaneously carry out the salting-out and the fusion, the particles (composite resin particles, colorant particles) under a temperature condition not lower than the glass transition temperature (Tg) of the resin constituting the composite resin particles.
Need to be aggregated.

In the salting-out / fusion step (II), together with the composite resin particles and the colorant particles, internal additive particles such as a charge control agent (fine particles having a number average primary particle diameter of about 10 to 1000 nm) are salted out. / It may be fused. The colorant particles may be surface-modified, and as the surface modifier,
Conventionally known ones can be used.

The colorant particles are subjected to salting out / fusion treatment in a state of being dispersed in an aqueous medium. The aqueous medium in which the colorant particles are dispersed is preferably an aqueous solution in which a surfactant is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC).

The disperser used for the dispersion treatment of the colorant particles is not particularly limited, but is preferably a stirrer “CLEARMIX (CLEARM) equipped with a high-speed rotating rotor.
MIX) "(manufactured by M-Technic), ultrasonic disperser,
Examples include a pressure disperser such as a mechanical homogenizer, a Manton-Gaulin, a pressure homogenizer, and a medium disperser such as a Getzman mill or a diamond fine mill.

In order to carry out salting out / fusion of the composite resin particles and the colorant particles, a salting-out agent having a critical coagulation concentration or more (aggregating agent) is added to the dispersion in which the composite resin particles and the colorant particles are dispersed. ) And heating the dispersion above the glass transition temperature (Tg) of the composite resin particles.

The preferred temperature range for salting out / fusing is (Tg + 10 ° C.) to (Tg + 50 ° C.)
It is particularly preferably (Tg + 15 ° C.) to (Tg + 40 ° C.). Further, in order to effectively perform the fusion, an organic solvent which is infinitely soluble in water may be added.

Filtration / Washing Step In this filtration / washing step, a filtration treatment for filtering the toner particles from the dispersion system of the toner particles obtained in the above-described step, and a filtration treatment for the toner particles (cake-like aggregate) are performed. ) Is subjected to a washing treatment for removing deposits such as surfactants and salting-out agents.

Here, the filtration method is not particularly limited, such as a centrifugal separation method, a reduced pressure filtration method using a Nutsche method, a filtration method using a filter press or the like.

Drying Step This step is a step of drying the washed toner particles.

Examples of the dryer used in this step include a spray dryer, a vacuum freeze dryer, and a reduced pressure dryer. A stationary shelf dryer, a movable shelf dryer, a fluidized bed dryer, a rotary bed dryer, It is preferable to use a type dryer, a stirring type dryer and the like.

The water content of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less.

Incidentally, the dried toner particles are
In the case where the aggregates are aggregated by a weak attraction between particles, the aggregates may be crushed. Here, as the crushing device,
A mechanical pulverizer such as a jet mill, a Henschel mixer, a coffee mill, and a food processor can be used.

The toner of the present invention forms the composite resin particles in the absence of the colorant as described above, and adds the dispersion of the colorant particles to the dispersion of the composite resin particles. It is preferably prepared by salting out / fusing the particles. As described above, by preparing the composite resin particles in a system in which no colorant is present, the polymerization reaction for obtaining the composite resin particles is not hindered.

Further, as a result of reliably performing the polymerization reaction for obtaining the composite resin particles, no monomer or oligomer remains in the obtained toner particles. No unpleasant odor is generated in the heat fixing step.

Next, each component used in the toner manufacturing process will be described in detail. (Polymerizable monomer) As the polymerizable monomer for producing the binder resin used in the present invention, a hydrophobic monomer is used as an essential component, and a crosslinkable monomer is used as necessary. Can be As described below, it is desirable to contain at least one monomer having an acidic polar group or a monomer having a basic polar group.

(1) Hydrophobic monomer The hydrophobic monomer constituting the monomer component is not particularly limited, and a conventionally known monomer can be used. In addition, one kind or a combination of two or more kinds can be used so as to satisfy required characteristics.

Specifically, a monovinyl aromatic monomer,
It is possible to use (meth) acrylate monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers, halogenated olefin monomers, and the like. it can.

Examples of the vinyl aromatic monomer include, for example,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n- Styrene-based monomers such as octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, 2,4-dimethylstyrene, and 3,4-dichlorostyrene, and derivatives thereof. .

The acrylic monomers include acrylic acid,
Methacrylic acid, methyl acrylate, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, β-hydroxyethyl acrylate, γ-aminopropyl acrylate, stearyl methacrylate, methacryl Dimethylaminoethyl acrylate, diethylaminoethyl methacrylate and the like.

Examples of the vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl benzoate and the like.

Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

Examples of the monoolefin-based monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.

(2) Crosslinkable monomer A crosslinkable monomer may be added to improve the properties of the resin particles. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

(3) Monomer having an acidic polar group Examples of the monomer having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (b) a sulfone. Α, β-ethylenically unsaturated compounds having a group (—SO ₃ H) can be mentioned.

Α, β- having a carboxyl group of (a)
Examples of ethylenically unsaturated compounds include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid,
Examples thereof include cinnamic acid, monobutyl maleate, monooctyl maleate, and salts of these metals such as Na and Zn.

Examples of the (b) α, β-ethylenically unsaturated compound having a sulfone group include sulfonated styrene,
Examples thereof include its Na salt, allylsulfosuccinic acid, octyl allylsulfosuccinate, and its Na salt.

(4) Monomer Having Basic Polar Group The monomer having a basic polar group (monomer) includes:
(I) an amine group or a quaternary ammonium group having 1 to 12 carbon atoms, preferably 2 to 8 carbon atoms, particularly preferably 2
(Meth) acrylates of aliphatic alcohols,
(Ii) (meth) acrylamide or (meth) acrylamide optionally mono- or di-substituted with an alkyl group having 1 to 18 carbon atoms on N, (iii) a heterocyclic group having N as a ring member Substituted vinyl compounds, and (iv)
N, N-diallyl-alkylamine or its quaternary ammonium salt can be exemplified. Among them, (i) the (meth) acrylic acid ester of an aliphatic alcohol having an amine group or a quaternary ammonium group is preferable as the monomer having a basic polar group.

Examples of the (meth) acrylate of an aliphatic alcohol having an amine group or a quaternary ammonium group (i) include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, Quaternary ammonium salts of four compounds, 3-dimethylaminophenyl acrylate, 2-hydroxy-
Examples thereof include 3-methacryloxypropyltrimethylammonium salt.

Examples of (ii) (meth) acrylamide or (meth) acrylamide optionally mono- or dialkyl-substituted on N include acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, Methacrylamide, N-butyl methacrylamide, N, N-dimethylacrylamide,
N-octadecylacrylamide and the like can be mentioned.

Examples of the vinyl compound (iii) substituted by a heterocyclic group having N as a ring member include vinylpyridine,
Vinyl pyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride and the like can be mentioned.

Examples of (iv) N, N-diallyl-alkylamine include N, N-diallylmethylammonium chloride, N, N-diallylethylammonium chloride and the like.

[Polymerization Initiator] The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (eg, potassium persulfate, ammonium persulfate, etc.), azo compounds (eg, 4,4 ′)
-Azobis-4-cyanovaleric acid and salts thereof, 2,2'-azobis (2-amidinopropane) salts and the like), peroxide compounds and the like. Further, the above radical polymerization initiator can be used as a redox initiator in combination with a reducing agent, if necessary. The use of a redox initiator is preferable because the polymerization activity is increased, the polymerization temperature can be reduced, and the polymerization time can be further shortened.

As the polymerization temperature, any temperature may be selected as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator. For example, a temperature in the range of 50 to 90 ° C. is used. However, by using a polymerization initiator started at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (such as ascorbic acid), it is possible to perform polymerization at room temperature or at a temperature somewhat higher than that.

[Chain Transfer Agent] For the purpose of adjusting the molecular weight, a known chain transfer agent can be used. The chain transfer agent is not particularly limited, for example, octyl mercaptan, dodecyl mercaptan,
A compound having a mercapto group such as tert-dodecyl mercaptan is used. In particular, a compound having a mercapto group is preferably used because it suppresses odor at the time of heating and fixing, and a toner having a sharp molecular weight distribution is obtained, and has excellent storage stability, fixing strength, and offset resistance. For example, ethyl thioglycolate, propyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate And compounds having a mercapto group of ethylene glycol, compounds having a mercapto group of neopentyl glycol, and compounds having a mercapto group of pentaerythritol. Among them, n-octyl-3-mercaptopropionate is particularly preferable from the viewpoint of suppressing odor during toner heat fixing.

[Surfactant] In order to carry out the miniemulsion polymerization using the above-mentioned polymerizable monomer, it is preferable to disperse oil droplets in an aqueous medium using a surfactant. Surfactants that can be used at this time are not particularly limited, but the following ionic surfactants can be mentioned as examples of suitable compounds.

Examples of the ionic surfactant include sulfonic acid salts (sodium dodecylbenzenesulfonate,
Sodium arylalkyl polyether sulfonate,
3,3-disulfonediphenylurea-4,4-diazo-
Sodium bis-amino-8-naphthol-6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol -6
Sodium sulfonate), sulfate salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.),
Fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc.) are exemplified.

Further, a nonionic surfactant can also be used. Specifically, for example, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, esters of polyethylene glycol and higher fatty acids, alkylphenol polyethylene oxide, esters of higher fatty acids and polyethylene glycol, esters of higher fatty acids and polypropylene oxide, And sorbitan esters.

In the present invention, these surfactants are mainly used as an emulsifier at the time of emulsion polymerization, but may be used in other steps or for other purposes.

[Molecular Weight Distribution of Resin Particles and Toner] The toner of the present invention has a peak or shoulder of 100,000 to 1,0.
Preferably, the peak or shoulder is 100,000, and between 1,000 and 50,000.
000-1,000,000, 25,000-150,
More preferably it is present between 000 and 1,000 to 50,000.

The molecular weight of the resin particles is from 100,000 to
A resin containing at least a high molecular weight component having a peak or shoulder in the region of 1,000,000 and a low molecular weight component having a peak or shoulder in the region of 1,000 to less than 50,000 is preferred. More preferably, it is preferable to use an intermediate molecular weight resin having a peak or shoulder at a peak molecular weight of 15,000 to 100,000.

The method for measuring the molecular weight of toner or resin is as follows.
The measurement is preferably performed by GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a solvent. That is, 1.0 ml of THF is added to 0.5 to 5 mg, more specifically, 1 mg of a measurement sample, and the mixture is stirred at room temperature using a magnetic stirrer or the like to be sufficiently dissolved. Then, pore size 0.45 to 0.50
After treating with a μm membrane filter, the mixture is injected into GPC. The GPC measurement conditions were as follows: the column was stabilized at 40 ° C., THF was flowed at a flow rate of 1.0 ml per minute, and 1 m
Approximately 100 μl of a sample at a concentration of g / ml is injected and measured. The column is preferably used in combination with a commercially available polystyrene gel column. For example, Shodex GPC KF-801, 802, 8 manufactured by Showa Denko KK
03, 804, 805, 806, 807, TSKgelG1000H, G2000H, manufactured by Tosoh Corporation,
G3000H, G4000H, G5000H, G600
0H, G7000H, TSKguard column
And the like. As the detector, a refractive index detector (IR detector) or a UV detector may be used. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodispersed polystyrene standard particles. It is preferable to use about 10 polystyrenes for preparing a calibration curve.

[Aggregating agent] The aggregating agent used in the present invention includes:
Those selected from metal salts are preferred.

Examples of the metal salt include salts of monovalent metals such as alkali metals such as sodium, potassium and lithium, salts of divalent metals such as alkaline earth metals such as calcium and magnesium, and salts of manganese and copper. Valent metal salts, iron,
Examples thereof include trivalent metal salts such as aluminum.

Specific examples of these metal salts are shown below.
Specific examples of metal salts of monovalent metals include sodium chloride,
Potassium chloride, lithium chloride, and metal salts of divalent metals include calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Examples of the trivalent metal salt include aluminum chloride and iron chloride. These are appropriately selected according to the purpose. In general, the divalent metal salt has a smaller critical aggregation concentration (coagulation value or coagulation point) than the monovalent metal salt, and the trivalent metal salt has a smaller critical aggregation concentration.

The critical aggregation concentration referred to in the present invention is an index relating to the stability of a dispersion in an aqueous dispersion, and indicates the concentration at which aggregation occurs when an aggregating agent is added. This critical aggregation concentration varies greatly depending on the latex itself and the dispersant. For example, Seizo Okamura et al., Polymer Chemistry 17,601
(1960), and according to these descriptions, the value can be known. Also, as another method,
It is also possible to add a desired salt to the target particle dispersion at a different concentration, measure the ζ potential of the dispersion, and determine the salt concentration at the point where the ζ potential changes to be the critical aggregation concentration.

In the present invention, the polymer fine particle dispersion is treated using a metal salt so as to have a concentration equal to or higher than the critical aggregation concentration. At this time, of course, add the metal salt directly,
The addition as an aqueous solution is arbitrarily selected depending on the purpose. In the case of adding as an aqueous solution, the added metal salt needs to be at or above the critical aggregation concentration of the polymer particles with respect to the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution.

The concentration of the metal salt as the coagulant in the present invention may be at least the critical coagulation concentration, but is preferably added at least 1.2 times, more preferably at least 1.5 times the critical coagulation concentration.

[Colorant] Examples of the colorant (colorant particles subjected to salting out / fusion with composite resin particles) constituting the toner of the present invention include various inorganic pigments, organic pigments, and dyes. Can be. Conventionally known inorganic pigments can be used. Specific inorganic pigments are exemplified below.

Examples of black pigments include furnace black, channel black, acetylene black,
Carbon black such as thermal black and lamp black, and magnetic powder such as magnetite and ferrite are also used.

These inorganic pigments can be used alone or in combination of two or more as desired. The amount of the pigment to be added is 2 to 20% by mass, preferably 3 to 15% by mass, based on the polymer.

When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, from the viewpoint of imparting predetermined magnetic characteristics, 20 to 6
It is preferable to add 0% by mass.

Conventionally known organic pigments and dyes can also be used. Specific examples of organic pigments and dyes are shown below.

As the pigment for magenta or red,
For example, C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I.
Pigment Red 6, C.I. I. Pigment Red 7,
C. I. Pigment Red 15, C.I. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I.
I. Pigment Red 53: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I.
I. Pigment Red 123, C.I. I. Pigment Red 139, C.I. I. Pigment red 144, C.I. I.
Pigment Red 149, C.I. I. Pigment Red 1
66, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222
And the like.

Examples of orange or yellow pigments include C.I. I. Pigment Orange 31, C.I.
I. Pigment Orange 43, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I.
Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 9
4, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment Yellow 1
85, C.I. I. Pigment yellow 155, C.I. I. Pigment Yellow 156 and the like.

The green or cyan pigments include:
For example, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 1
5: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63
111, 122, C.I. I. Solvent Yellow 1
9, 44, 77, 79, 81, 82, 9
3, 98, 103, 104, 112, 16
2, C.I. I. Solvent Blue 25, 36, 60
70, 93, 95, etc., and mixtures thereof can also be used.

These organic pigments and dyes can be used alone or in combination of two or more as desired.
The amount of the pigment added is 2 to 20% by mass based on the polymer.
And preferably 3 to 15% by mass.

The colorant (colorant particles) constituting the toner of the present invention may be surface-modified. As the surface modifier, a conventionally known one can be used, and specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent and the like can be preferably used. Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, and vinyltrimethoxysilane. Chlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,
γ-ureidopropyltriethoxysilane and the like. As the titanium coupling agent, for example, TTS, 9S, 38S, 41B, 46B, 55, 138, which are commercially available under the trade name of “Plenact” manufactured by Ajinomoto Co., Inc.
S-1, 238S, etc., commercial products A-1 and B- manufactured by Nippon Soda Co., Ltd.
1, TOT, TST, TAA, TAT, TLA, TO
G, TBSTA, A-10, TBT, B-2, B-4,
B-7, B-10, TBSTA-400, TTS, TO
A-30, TSDMA, TTAB, TTOP and the like. As the aluminum coupling agent, for example,
"Plenact AL-M" manufactured by Ajinomoto Co. and the like.

The addition amount of these surface modifiers is preferably from 0.01 to 20% by mass, more preferably from 0.1 to 5% by mass, based on the colorant.

Examples of the method for modifying the surface of the colorant particles include a method in which a surface modifier is added to a dispersion of the colorant particles, and the system is heated and reacted.

[0176] The surface-modified colorant particles are collected by filtration, and are dried after washing and filtering with the same solvent are repeated.

[Release Agent] The toner used in the present invention comprises:
It is preferable that the toner is obtained by fusing resin particles containing a release agent in an aqueous medium. In this manner, the resin particles in which the release agent is encapsulated in the resin particles are salted out / fused with the colorant particles in an aqueous medium, whereby a toner in which the release agent is finely dispersed can be obtained.

In the toner of the present invention, a low molecular weight polypropylene (number average molecular weight 1500 to 900) is used as a releasing agent.
0), low molecular weight polyethylene, and the like are preferable, and an ester compound represented by the following formula is particularly preferable.

R ^1- (OCO-R ² ) _{n In the} formula, n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4. R ¹ , R
² represents a hydrocarbon group which may have a substituent. R ¹
Has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, and more preferably 2 to 5 carbon atoms. R ² has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 18 to 26 carbon atoms.

Next, examples of typical compounds are shown below.

[0181]

Embedded image

[0182]

Embedded image

The addition amount of the above compound is 1 to 30% by mass, preferably 2 to 20% by mass, more preferably 3 to 15% by mass based on the whole toner.

The toner of the present invention is preferably prepared by encapsulating the above-mentioned releasing agent in resin particles by a miniemulsion method, salting out and fusing together with the colored particles.

[Diameter of Toner Particles] The particle diameter of the toner of the present invention is preferably 2 to 10 μm, more preferably 3 to 8 μm in number average particle diameter. This particle size is
In the method for producing a toner, it can be controlled by the concentration of the coagulant (salting agent), the amount of the organic solvent added, the fusing time, and the composition of the polymer.

The toner particles are particles obtained by adding an external additive to at least colored particles composed of a binder resin and a colorant. The particle size and shape of the toner particles before and after the addition of the external additive are determined. ,
No difference appears in the measured values.

When the number average particle diameter is 3 to 10 μm, in the fixing step, toner particles having a large adhesive force which fly and adhere to the heating member to generate offset are reduced, and the transfer efficiency is increased. The halftone image quality is improved, and the image quality of fine lines and dots is improved.

The number average particle diameter of the toner is determined by using a Coulter Counter TA-II, a Coulter Multisizer, a SLAD
It can be measured using 1100 (a laser diffraction particle size analyzer manufactured by Shimadzu Corporation) or the like.

In the present invention, a Coulter Multisizer was used, and an interface for outputting the particle size distribution (manufactured by Nikkaki Co., Ltd.) and a personal computer were connected. The particle size distribution and the average particle size were calculated by measuring the volume distribution of toner having a size of 2 μm or more (for example, 2 to 40 μm) using an aperture of 100 μm as the aperture in the Coulter Multisizer.

[Preferable Shape Factor Range of Toner Particles]
The shape factor of the toner of the present invention is represented by the following equation, and indicates the degree of roundness of toner particles.

Shape coefficient = ((maximum diameter / 2) ² × π) / projected area Here, the maximum diameter is defined as a parallel line when a projected image of a toner particle on a plane is sandwiched between two parallel lines. Means the width of the particle at which the distance between the particles becomes maximum. The projection area refers to the area of the projected image of the toner particles on the plane. In the present invention, the shape factor can be determined by taking a photograph in which the toner particles are magnified 2,000 times with a scanning electron microscope, and then referring to the “SCCANNING IMAGE ANALYZE” based on the photograph.
R "(manufactured by JEOL Ltd.) was used to analyze photographic images. In this case, the shape factor of the present invention was measured by using the above formula using 100 toner particles.

In the toner of the present invention, when the particle size of the toner particles is D (μm), the natural logarithm InD is plotted on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the particle size distribution, the sum (M1) of the relative frequency (m1) of the toner particles included in the most frequent class and the relative frequency (m2) of the toner particles included in the class having the second highest frequency after the most frequent class. ) Is preferably 70% or more.

When the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrower. Thus, the occurrence of selective development can be reliably suppressed.

In the present invention, the histogram showing the number-based particle size distribution is obtained by plotting a natural logarithm lnD (D: particle size of individual toner particles) in a plurality of classes (0 to 0) at intervals of 0.23.
0.23: 0.23 to 0.46: 0.46 to 0.69:
0.69 to 0.92: 0.92 to 1.15: 1.15
1.38: 1.38 to 1.61: 1.61 to 1.84:
1.84 to 2.07: 2.07 to 2.30: 2.30 to
2.53: 2.53 to 2.76...) Is a histogram showing the number-based particle size distribution, which is a particle size data of a sample measured by a Coulter Multisizer according to the following conditions. Is transferred to a computer via an I / O unit, and the computer creates the program using a particle size distribution analysis program.

Measurement conditions 1: Aperture: 100 μm 2: Sample preparation method: Electrolyte [ISOTON R-11
(Coulter Scientific Japan) 5
An appropriate amount of a surfactant (neutral detergent) is added to 0 to 100 ml, and the mixture is stirred, and 10 to 20 mg of a measurement sample is added thereto. This system is prepared by subjecting it to a dispersion treatment with an ultrasonic disperser for 1 minute.

With respect to the toner particles, by using a toner composed of toner particles having a shape coefficient variation coefficient of 16% or less and a number variation coefficient of 27% or less in the number particle size distribution, the outer surface on the toner surface is reduced. The presence of the additive becomes uniform, the charge amount distribution becomes sharp, and high fluidity is obtained. As a result, excellent developability and fine line reproducibility and stable cleaning properties can be formed for a long period of time.

Further, the inventors of the present invention focused on the minute shape of each toner particle, and as a result, the shape of the corner portion of the toner particle changed inside the developing device and became round, and the portion became round. It was found that the embedding of the external additive was promoted, and the change in the charge amount, the fluidity, and the cleaning property were reduced.

In addition, when electric charge is applied to toner particles by frictional charging, it is presumed that the external additive tends to be buried particularly in corner portions, and the toner particles are likely to be non-uniformly charged.

That is, the ratio of toner particles having no corners is 50% by number or more, and the number variation coefficient in the number particle size distribution is 2%.
It has also been found that by using a toner composed of toner particles controlled to 7% or less, it is possible to form a high-quality image over a long period of time with excellent developability and fine line reproducibility.

In the present invention, the toner particles having no corners mean toner particles having substantially no protrusions on which electric charges are concentrated or protrusions which are easily worn by stress. The toner particles are called cornerless toner particles. That is, as shown in FIGS. 2A, 2B, and 2C, the toner particle is a circle having a major axis of L and a radius R of L / 10, which is in contact with the toner particle peripheral line at one point. When the inside rolls out while the circle does not substantially protrude outside the toner, it is referred to as a cornerless toner particle.
The case where the protrusion does not substantially protrude means that one or more protrusions have a protruding circle. In addition, the major axis of the toner particle refers to the width of the particle at which the interval between the parallel lines becomes maximum when the projected image of the toner particle on the plane is sandwiched between two parallel lines.

The measurement of the toner having no corners was performed as follows. First, a photograph in which toner particles are enlarged by a scanning electron microscope is taken, and further enlarged to obtain a photographic image of 15,000 times. Next, the presence or absence of the corners is measured for this photographic image. This measurement was performed for 100 toner particles.

In the toner of the present invention, the ratio of toner particles having no corners is preferably 50% by number or more, more preferably 70% by number or more. When the ratio of the toner particles having no corners is 50% by number or more, it is difficult to generate fine particles due to stress with the developer conveying member, and so-called excessively adherent toner to the surface of the developer conveying member. Can be prevented, contamination of the developer conveying member can be suppressed, and the charge amount can be sharpened. Also,
The amount of toner particles that are easily worn or broken and the number of toner particles having a portion where charges are concentrated are reduced, the charge amount distribution is sharpened, the chargeability is stabilized, and good image quality can be formed over a long period of time.

The method for obtaining a toner having no corners is not particularly limited. For example, as described above, as a method of controlling the shape coefficient, a method of spraying toner particles into a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, or a method of dissolving a toner It can be obtained by adding to a solvent that does not contain and giving a swirling flow.

Further, it was found that even when the toner was made to have a specific shape and the shape was made uniform, the external additive was not buried and the charge amount distribution became sharp.

That is, even if a toner having a shape coefficient in the range of 1.2 to 1.6 in which the proportion of toner particles is 65% by number or more and a coefficient of variation of the shape coefficient is 16% or less is used, And high quality images can be formed over a long period of time.

[Developer] The toner of the present invention may be used as a one-component developer or a two-component developer.

When used as a one-component developer, a non-magnetic one-component developer or 0.1 to 0.5 μm
And a magnetic one-component developer containing a certain amount of magnetic particles, and any of them can be used. In particular, stable charging performance is exhibited even for a non-magnetic one-component toner whose charging performance is usually unstable.

Further, it can be used as a two-component developer by mixing with a carrier. In this case, as magnetic particles of the carrier, metals such as iron, ferrite and magnetite,
Conventionally known materials such as alloys of these metals with metals such as aluminum and lead can be used. Particularly, ferrite particles are preferable. The magnetic particles have a volume average particle size of 15 to 100 μm, more preferably 25 to 8 μm.
It is preferably 0 μm.

The volume average particle size of the carrier is typically measured by a laser diffraction particle size distribution analyzer “HELOS” equipped with a wet disperser (SYMPATIC (SYMPIC)).
(ATEC)).

[0210] The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. Although there is no particular limitation on the resin composition for coating, for example, an olefin resin, a styrene resin, a styrene-acrylic resin, a silicone resin, a polyester resin, or a fluorine-containing polymer resin is used. Also,
The resin for constituting the resin dispersion type carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin,
Fluorine-containing polymer resins, phenolic resins and the like can be used.

[Image Forming Method] Next, the image forming apparatus of the present invention will be described.

FIG. 3 is a sectional view showing an example of the image forming apparatus of the present invention. Reference numeral 4 denotes a photosensitive drum as an object to be charged, which is formed by forming an organic photoconductor (OPC) as a photosensitive layer on an outer peripheral surface of a drum base made of aluminum, and rotates at a predetermined speed in a direction indicated by an arrow. .

In FIG. 3, exposure light is emitted from the semiconductor laser light source 1 based on information read by a document reading device (not shown). This is distributed by a polygon mirror 2 in the direction perpendicular to the paper surface of FIG. 3, and is irradiated on the photoreceptor surface via an fθ lens 3 for correcting image distortion to form an electrostatic latent image. The photoconductor drum 4 is provided with a charger 5 in advance.
, And starts to rotate clockwise in accordance with the timing of image exposure.

The electrostatic latent image on the surface of the photosensitive drum is
The developed image is transferred to the transfer paper 8 conveyed at a proper timing by the operation of the transfer device 7. Further, the photosensitive drum 4 and the transfer paper 8 are separated by a separator (separation pole) 9, and the developed image is transferred and carried on the transfer paper 8, guided to the fixing device 10 and fixed.

The untransferred toner remaining on the photoreceptor surface is
It is cleaned by a cleaning device 11 of a cleaning blade type, and the remaining charge is removed by a pre-charging exposure (PCL) 12, and is uniformly charged again by the charger 5 for the next image formation.

(Toner Recycling System) The method for recycling the toner is not particularly limited. For example, the toner collected by the cleaning unit is supplied by a transport conveyor or a transport screw with a replenishing toner hopper, a developing device, A method of mixing the replenishing toner with the intermediate chamber and supplying the mixed toner to the developing device can be used. Preferably, a method of directly returning the toner to the developing device or a method of mixing the replenishment toner and the recycled toner in the intermediate chamber and supplying the mixed toner can be used.

Next, FIG. 4 shows an example of a perspective configuration diagram of a toner recycling member. In this method, the recycled toner is directly returned to the developing device.

The untransferred toner collected by the cleaning blade 13 is collected in a toner recycle pipe 14 by a transport screw in the cleaning device 11, and is returned to the developing device 6 from a receiving port 15 of the recycle pipe to be used again as a developer. Is done.

FIG. 4 is also a perspective view of a process cartridge detachable from the image forming apparatus of the present invention. In FIG. 4, the photoreceptor unit and the developer unit are separated so that the perspective structure can be easily understood, but they can be removably mounted as an integrated unit in the image forming apparatus. In this case, the photoreceptor, the developing device, the cleaning device, and the recycling member are integrated to form a process cartridge.

[0220] The image forming apparatus may be configured to mount a process cartridge including a photosensitive drum and at least one of a charging device, a developing device, a cleaning device, and a recycling member.

The transfer paper is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and of course includes a PET base for OHP.

The cleaning blade 13 has a thickness of 1 mm.
A rubber-like elastic body of about 30 mm is used, and urethane rubber is most often used as a material. Since this is used by being pressed against the photoconductor, it is easy to conduct heat. In the present invention, it is desirable to provide a release mechanism and keep the photoconductor away from the photoconductor when the image forming operation is not performed.

The present invention can also be used in an image forming apparatus by electrophotography, particularly in an apparatus for forming an electrostatic latent image on a photoreceptor by a modulated beam modulated with digital image data from a computer or the like.

In recent years, in the field of electrophotography and the like in which an electrostatic latent image is formed on a photoreceptor and this latent image is developed to obtain a visible image, it is easy to improve the image quality, convert, edit, etc., and obtain a high quality image. Research and development of an image forming method employing a digital method capable of forming are being actively conducted.

As a scanning optical system that modulates light with a digital image signal from a computer or a copy original used in the image forming method and apparatus, an acousto-optic modulator is interposed in a laser optical system, and the There is a device for modulating the light and a device for directly modulating the laser intensity using a semiconductor laser. These scanning optical systems form a dot-like image by spot exposure on a uniformly charged photoconductor.

The beam emitted from the above-described scanning optical system has a round or elliptical luminance distribution approximating a normal distribution with a skirt spreading left and right. One or both of the scanning direction and the sub-scanning direction has an extremely narrow round or elliptical shape of 20 to 100 μm.

(Fixing Device) The toner of the present invention is used to transfer the transfer paper (image forming support) on which the toner image is formed between the heating roller 70 and the pressure roller 72 which constitute a fixing device (fixing device). Is preferably used for an image forming method including a step of fixing by passing through.

FIG. 5 is a schematic sectional view showing an example of a fixing device used in the image forming method using the toner of the present invention. The fixing device shown in FIG. 5 includes a heating roller 70 and a pressure roller 72 that comes into contact with the heating roller 70. In addition,
In FIG. 5, T is a toner image formed on the transfer paper.

The heating roller 70 has a coating layer 82 made of a fluororesin or an elastic body formed on the surface of a cored bar 81, and includes a heating member 75 made of a linear heater.

The core bar 81 is made of metal and has an inner diameter of 10 to 70 mm. The metal constituting the metal core 81 is not particularly limited, but examples thereof include metals such as iron, aluminum, and copper, and alloys thereof.

The thickness of the core bar 81 is set to 0.1 to 15 mm, and is determined in consideration of a balance between a demand for energy saving (thinning) and a strength (depending on a constituent material). For example,
In order to maintain a strength equivalent to that of a 0.57 mm iron core with an aluminum core, the wall thickness must be 0.8 mm.

The fluororesin constituting the coating layer 82 includes PTFE (polytetrafluoroethylene) and P
FA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) and the like can be exemplified.

The thickness of the coating layer 82 made of fluororesin is 1
It is 0-500 μm, preferably 20-400 μm.

When the coating layer 82 made of fluororesin has a thickness of 1
When the thickness is less than 0 μm, the function as a coating layer cannot be sufficiently exhibited, and the durability as a fixing device cannot be secured. On the other hand, there is a problem that the surface of the coating layer having a thickness of more than 500 μm is easily scratched by paper dust, and toner or the like adheres to the scratched portion, thereby causing image stains.

As the elastic body constituting the coating layer 82, it is preferable to use silicone rubber and silicone sponge rubber having good heat resistance such as LTV, RTV, and HTV.

Elastic Asker C constituting the coating layer 82
The hardness is less than 80 °, preferably less than 60 °.

The thickness of the coating layer 82 made of an elastic material is 0.1 to 30 mm, preferably 0.1 to 20 mm.
It is said.

Elastic Asker C constituting the coating layer 82
If the hardness exceeds 80 ° and the thickness of the coating layer 82 is less than 0.1 mm, the fixing nip cannot be increased, and the effect of soft fixing (for example, the smoothed interface Improvement effect of color reproducibility by toner layer)
Cannot be demonstrated.

As the heating member 75, a halogen heater can be suitably used. The pressure roller 72 is
A coating layer 84 made of an elastic material is formed on the surface of the core bar 83. The elastic body that forms the coating layer 84 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber and sponge rubber. It is preferable to use silicone sponge rubber.

Elastic Asker C constituting the coating layer 84
The hardness is less than 80 °, preferably less than 70 °, more preferably less than 60 °.

The thickness of the coating layer 84 is 0.1 to 30 m.
m, and preferably 0.1 to 20 mm.

An elastic Asker C constituting the coating layer 84
When the hardness exceeds 80 ° and when the thickness of the coating layer 84 is less than 0.1 mm, the nip for fixing cannot be increased, and the effect of soft fixing cannot be exhibited.

The material constituting the core bar 83 is not particularly limited, but examples thereof include metals such as aluminum, iron and copper or alloys thereof.

The contact load (total load) between the heating roller 70 and the pressure roller 72 is generally 40 to 350 N, preferably 50 to 300 N, and more preferably 50 to 300 N.
２５０250N. This contact load is applied to the heating roller 7
It is defined in consideration of the strength of 0 (the thickness of the core bar 81). For example, in the case of a heating roller having a core bar made of iron of 0.3 mm, the heating roller is preferably set to 250 N or less.

Further, from the viewpoint of offset resistance and fixing property, the nip width is preferably 4 to 10 mm, and the surface pressure of the nip is 0.6 × 10 ^{5 to} 1.5 × 1.
It is preferably 0 ⁵ Pa.

As an example of the fixing conditions by the fixing device shown in FIG. 4, the fixing temperature (surface temperature of the heating roller 70) is set to 150 to 210 ° C., and the fixing linear speed is set to 80 to 640 mm.
/ Sec.

The fixing device used in the present invention may be provided with a cleaning mechanism as required. In this case, as a method of supplying the silicone oil to the upper roller (heating roller) of the fixing unit, a method of supplying and cleaning with a pad, a roller, a web, or the like impregnated with the silicone oil can be used.

As the silicone oil, those having high heat resistance are used, and polydimethyl silicone, polyphenylmethyl silicone, polydiphenyl silicone and the like are used. Since those having a low viscosity have a large outflow during use, those having a viscosity at 20 ° C. of 1 to 100 Pa · s are preferably used.

By setting the supply amount of the silicone oil to 2 mg or less per A4 sheet, the amount of the silicone oil adhering to the transfer paper (image support) after fixing is reduced, and the ballpoint pen is formed by the silicone oil adhering to the transfer paper. There is no difficulty in writing with an oil-based pen, etc., and the writing performance is not impaired. Further, it is possible to avoid problems such as deterioration of the anti-offset property with time due to deterioration of the silicone oil and contamination of the optical system and the band electrode by the silicone oil.

Here, the supply amount of the silicone oil was transferred to a fixing device (between the rollers) heated to a predetermined temperature by a transfer paper (A4).
100 sheets of white paper of the same size are continuously passed, and the mass change (Δw) of the fixing device before and after the paper passing is measured and calculated (Δw / 100).

[0251]

Next, embodiments of the present invention will be described in more detail with reference to examples, but of course, embodiments of the present invention are not limited thereto.

Production Example of Resin Particles for Toner [Preparation Example 1 of Composite Resin Particles] (Latex: 1HML) (1) Preparation of Core Particles (First Stage Polymerization) A stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device were used. An anionic surfactant (sodium dodecylsulfonate: SD) is added to the attached 5000 ml separable flask.
S) A surfactant solution (aqueous medium) in which 7.08 g was dissolved in 3010 g of ion-exchanged water was charged, and the solution was added under a nitrogen stream.
The internal temperature was raised to 80 ° C. while stirring at a stirring speed of 0 rpm.

To this surfactant solution was added 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water.
Was added, and the temperature was adjusted to 75 ° C., and then 70.1 g of styrene and n-butyl acrylate 1 were added.
A monomer mixture composed of 9.9 g and 10.9 g of methacrylic acid was added dropwise over 1 hour. This system is heated and stirred at 75 ° C. for 2 hours to perform polymerization (first-stage polymerization).
To prepare a latex (a dispersion of resin particles composed of a high molecular weight resin). This is designated as “latex (1H)”.

(2) Formation of Intermediate Layer (Second Stage Polymerization) In a flask equipped with a stirrer, styrene 1
A compound represented by the above formula 19) was added to a monomer mixture comprising 05.6 g, 30.0 g of n-butyl acrylate, 6.4 g of methacrylic acid, and 5.6 g of n-octyl-3-mercaptopropionate. Hereinafter, "Exemplified Compound 1"
9) ". ) 72.0 g was added, and the mixture was heated to 80 ° C and dissolved to prepare a monomer solution.

On the other hand, an anionic surfactant (SDS)
A surfactant solution obtained by dissolving 1.6 g in 2700 ml of ion-exchanged water was heated to 80 ° C.
After adding 28 g of the latex (1H), which is a dispersion of core particles, in terms of solid content, using a mechanical disperser “CLEARMIX” (manufactured by M-Technic) having a circulation path, Exemplified Compound 19) Was mixed and dispersed to prepare a dispersion liquid (emulsion liquid) containing emulsified particles (oil droplets) having a uniform dispersed particle diameter (284 nm).

Next, to this dispersion liquid (emulsion liquid) were added an initiator solution obtained by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water, and 750 ml of ion-exchanged water. Polymerization (second stage polymerization) is performed by heating and stirring at 3 ° C. for 3 hours, and latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin is coated with an intermediate molecular weight resin) is used. Obtained.
This is referred to as “latex (1HM)”.

(3) Formation of outer layer (third stage polymerization) To the latex (1HM) obtained as described above, 7.4 g of a polymerization initiator (KPS) was added to 200 ml of ion-exchanged water.
Was added to the initiator solution. Next, under a temperature condition of 80 ° C., 300 g of styrene, 95 g of n-butyl acrylate, 15.3 g of methacrylic acid, and n-octyl-3-
A monomer mixture composed of 10.4 g of mercaptopropionate was added dropwise over 1 hour.

After completion of the dropping, polymerization (third-stage polymerization) was carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to form a latex (a central portion composed of a high molecular weight resin and an intermediate layer composed of an intermediate molecular weight resin). And an outer layer made of a low-molecular-weight resin, and a dispersion liquid of composite resin particles containing the exemplified compound 19) in the intermediate layer was obtained. This latex is referred to as “latex (1HML)”.

The composite resin particles constituting the latex (1HML) were 138,000, 80,000 and 1
It has a peak molecular weight of 3,000,
The number average particle diameter of the composite resin particles was 102 nm.

[Preparation Example 2 of Composite Resin Particles] (1) Preparation of core particles (first-stage polymerization) In a flask equipped with a stirrer, styrene 1 was added.
To a monomer mixture comprising 05.6 g, n-butyl acrylate 30.0 g, and methacrylic acid 6.4 g, the above formula 1 was added.
72.0 g of the compound represented by 6) (hereinafter referred to as “exemplary compound 16”) was added, and the mixture was heated to 80 ° C. and dissolved to prepare a monomer solution.

On the other hand, an anionic surfactant (SDS)
A surfactant solution obtained by dissolving 1.6 g in 2700 ml of ion-exchanged water was heated to 80 ° C.
Mechanical dispersion machine with a circulation path "CLEARMIX (CL
EARMIX) ”(manufactured by M-Technic Co., Ltd.), by mixing and dispersing the monomer solution of Exemplified Compound 16), and a dispersion (emulsion liquid) containing emulsified particles (oil droplets) having a uniform dispersion particle diameter (268 nm) Was prepared.

Next, to this dispersion liquid (emulsion liquid) were added an initiator solution in which 5.1 g of a polymerization initiator (KPS) was dissolved in 240 ml of ion-exchanged water, and 750 ml of ion-exchanged water. Polymerization (first-stage polymerization) was carried out by heating and stirring at 3 ° C. for 3 hours to prepare a latex (a dispersion of resin particles composed of a high molecular weight resin). This is designated as “latex (2H)”.

(2) Formation of outer layer (second stage polymerization) To the latex (2H) obtained as described above, 14.8 g of a polymerization initiator (KPS) was added to 400 ml of ion-exchanged water.
Was added thereto, and under a temperature condition of 80 ° C., 600 g of styrene and 190 g of n-butyl acrylate.
g, 30.0 g of methacrylic acid, and 20.8 g of n-octyl-3-mercaptopropionate were dropped over 1 hour. After completion of the dropping, polymerization (second-stage polymerization) is carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to have a latex (having a central portion composed of a high molecular weight resin and an outer layer composed of a low molecular weight resin). ,
A dispersion liquid of composite resin particles containing Exemplified Compound 16) in the center was obtained. This latex is referred to as “latex (2HL)”.

The composite resin particles constituting the latex (2HL) had peak molecular weights of 168,000 and 11,000, and the weight average particle diameter of the composite resin particles was 126 nm.

[Production Examples 1-4 of Colored Particles] 59.0 g of sodium n-dodecyl sulfate was added to 1600 ml of ion-exchanged water.
Was stirred and dissolved. While stirring the solution, carbon black “REGAL 330” (Cabot) 420.
0 g was gradually added, and then dispersion treatment was performed using "CLEARMIX" (manufactured by M-Technic) to prepare a dispersion of colorant particles (hereinafter referred to as "colorant dispersion"). . The particle size of the colorant particles in this colorant dispersion liquid was measured using an electrophoretic light scattering photometer “ELS-80”.
When measured using "0" (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle diameter was 98 nm.

420.7 g of the latex (1HML) obtained in Preparation Example 1 of the composite resin particles (in terms of solid content), 900 g of ion-exchanged water, and 166 g of a colorant dispersion were introduced into a temperature sensor, a cooling pipe, and nitrogen introduction. The mixture was stirred in a reaction vessel equipped with an apparatus, a stirrer, and a monitoring device for particle size and shape. After adjusting the internal temperature to 30 ° C., a 5 mol / L aqueous sodium hydroxide solution was added to the solution to adjust the pH to 11.1.
Adjusted to zero.

Subsequently, magnesium chloride hexahydrate12.
An aqueous solution obtained by dissolving 1 g in 1000 ml of ion-exchanged water,
The solution was added at 30 ° C. over 10 minutes with stirring. After standing for 3 minutes, heating was started, and the system was heated to 90 ± 3 ° C. over 6 to 10 minutes (heating rate 10 ° C./min).

In that state, “Coulter counter TA
-II ", and when the volume average particle size became 5.5 μm, 80.4 g of sodium chloride was measured.
Was dissolved in 1000 ml of ion-exchanged water to stop the particle growth. Further, as an aging treatment, the mixture was heated and stirred at a liquid temperature of 85 ± 2 ° C. for 0.5 to 15 hours to continue the fusion. . Thereafter, the mixture was cooled to 30 ° C. under the condition of 8 ° C./min, the pH was adjusted to 2.0 by adding hydrochloric acid, and the stirring was stopped. The generated associated particles are filtered using a Nutsche, washed repeatedly with ion-exchanged water, and then, using a flash jet drier, with an intake air temperature of 6.
Dry at 0 ° C. and then use a fluid bed drier at 60 ° C.
To obtain colored particles containing a release agent [exemplified compound 19]].

In the above-mentioned monitoring of the fusing step and the shape control step, by controlling the number of rotations of the stirring and the heating time, the variation coefficient of the shape and the shape factor is controlled, and the variation coefficient of the particle size and the particle size distribution can be arbitrarily determined. Adjust,
Colored particles 1 to 4 having the shape characteristics and particle size distribution characteristics shown in Table 1 were obtained.

[Production Examples 5 to 7 of Colored Particles] In place of latex (1HML), 420.7 g (in terms of solid content) of the latex (2HL) obtained in Preparation Example 2 of composite resin particles
And colored particles 5 to 7 having the shape characteristics and the particle size distribution characteristics shown in Table 2 were obtained in the same manner as in Colored Particle Production Examples 1 to 4 except that the aging time was changed.

[0271]

[Table 1]

Hydrophobic silica a1 Pearl necklace-shaped colloidal silica (Snowtex PS-M, particles having a particle diameter of 18 to 23 nm covalently bonded in a branched shape to form 100 to 200 nm: manufactured by Nissan Chemical Industries, Ltd.), 100 mass Part in a container having a high-speed mixer and stirring at 8500 rpm in a nitrogen atmosphere.
After spraying 20 parts by mass of dimethyldichlorosilane and further stirring for 5 minutes, the obtained powder liquid was refluxed and stirred at 200 ° C. for 3 hours under a nitrogen stream. afterwards,
After cooling to room temperature, hydrophobic silica a1 was obtained.

Hydrophobic Silica a2 In the production of hydrophobic silica a1, pearl necklace-shaped colloidal silica (Snowtex PS-L, 35-40
80 to 190 covalently bonded particles having a size of 10 nm
0 to 200 nm: manufactured by Nissan Chemical Industries, Ltd.) except that hydrophobic silica a1 was used in the same manner as hydrophobic silica a1.
2 was obtained.

Comparative Hydrophobic Silica a3 In the production of hydrophobic silica a1, commercially available spherical colloidal silica (Snowtex S, manufactured by Nissan Chemical Co.,
Comparative hydrophobic silica a3 was obtained in the same manner as the hydrophobic silica a1 except that 11 nm) was used.

Hydrophobic silica b1 used in combination Fumed silica having a primary particle diameter of 0.007 μm (100
Parts by mass) was placed in a container having a high-speed mixer, and 20 parts by mass of dimethyldichlorosilane was sprayed while stirring at 8500 rpm in a nitrogen atmosphere, and the mixture was further stirred for 5 minutes. At 200 ℃
For 3 hours under reflux. Thereafter, the mixture was cooled to room temperature to obtain a hydrophobic silica powder b1.

Hydrophobic Silica b2 Used in Combination In the preparation example of the hydrophobic silica b1, the primary particle diameter was 0.00
Primary particle size 0.0 instead of 7 μm fumed silica
A hydrophobic silica b2 was obtained in the same manner as the hydrophobic silica b1, except that octyltrimethoxysilane was used instead of dimethyldichlorosilane for fumed silica of 12 μm.

For each 100 parts by mass of each of the colored particles 1 to 7, 1
Parts by mass as shown in Table 2 below, and the peripheral speed of the rotor was set to 24 m / h with a 10-liter Henschel mixer.
s and mixed for 15 minutes. The shape and particle size of these colored particles do not change depending on the addition of the external additive.

[0278]

[Table 2]

BET of External Additive Particles Present on Toner Surface
Table 3 shows the results of ESCA measurement of specific surface area and surface abundance (area%).

[0280]

[Table 3]

[Evaluation of Characteristics] A commercially available digital copier equipped with a toner recycling system, Sitio manufactured by Konica Corporation
s A Konica 7030 remodeling machine equipped with a non-magnetic one-component developer was installed in a high-temperature, high-humidity environment (33 ° C, 80% R
H), a real-photograph test was performed to continuously form 100,000 sheets of images with a low pixel rate (pixel rate of 2%), and then the environment dependence of image density, uniformity of halftone, dust of fine dots, and characters The crushing and fogging were evaluated.

In a toner recycling system, continuous printing of an image with a low pixel rate under a high temperature and high humidity environment is a severe condition for the following items because embedding of an external additive is promoted.

<Environmental Dependence of Image Density> The maximum image density of the solid image portion was measured with a Macbeth reflection densitometer. High temperature and high humidity environment (33 ° C, 80% RH) and low temperature and low humidity environment (1
At 0 ° C., 20% RH), a difference of less than 0.05 was evaluated as “◎”, 0.05 to 0.1 as “○”, and 0.1 or more as “x”.

<Uniformity of Halftone> The uniformity of halftone was visually determined, and the uniformity of halftone images was evaluated. The rank was evaluated as follows.

Rank A: uniform image without unevenness Rank B: presence of stripe-like thin unevenness Rank C: presence of several stripe-like thin unevenness Rank D: presence of stripe-like clear unevenness <fine dot dust> A 10% halftone dot image was formed on the entire image, and dust around the dots was observed with a loupe. The symbol "◎" indicates that dust was hardly detectable, the symbol "○" indicates that dust was slightly noticeable if not carefully observed, and the symbol "x" indicates that dust was easily detectable.

<Situation of Fogging> The relative density of the specific image area with respect to the white background density was measured with a Macbeth densitometer.

“◎”: less than 0.002 “○”: 0.002 to less than 0.005 “×”: 0.005 or more <Spot-like toner stain> 10 continuous sheets, a white background image was formed on the entire image, 0.5μ diameter due to scattering of toner aggregates
"x" indicates that a black spot of m or more occurred, and "o" indicates that no black spot occurred.

The results are shown in Table 4.

[0289]

[Table 4]

As is clear from Table 4, Examples 1 to 8 in the present invention have excellent characteristics, but Comparative Example 1 outside the present invention has a problem in any of the characteristics.

[0291]

According to the present invention, a stable image can be obtained which has excellent fluidity, has no image contamination due to scattering of toner granules and toner aggregates even under severe use conditions, and has a small decrease in halftone homogeneity due to toner external additive burial. Thus, it is possible to provide a toner for developing an electrostatic image, which has a uniform charge distribution, a sharp image with less fine dot dust, and a low environmental dependency.

Even when used in an image forming method or apparatus incorporating a toner recycling system, no failure such as black spots occurs in the image, and there is no decrease in toner fluidity or chargeability. It is possible to provide a toner for developing an electrostatic image without fogging, an image forming method, and an image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a shape in which fine particles are combined in a chain or branch.

FIG. 2 is a schematic diagram illustrating a toner particle having no corners.

FIG. 3 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus.

FIG. 4 is a perspective configuration diagram of a toner recycling member.

FIG. 5 is a schematic sectional view showing an example of a fixing device.

[Explanation of symbols]

 Reference Signs List 1 semiconductor laser light source 2 polygon mirror 3 fθ lens 4 photoreceptor drum 5 charger 6 developing device 7 transfer device 8 transfer paper 9 separator (separation pole) 10 fixing device 11 cleaning device 12 pre-charge exposure (PCL) 13 cleaning blade 14 Toner recycling pipe

Claims (12)

[Claims] 1. An electrostatic latent image developing toner obtained by adding an external additive to colored particles comprising at least a binder resin and a colorant, wherein the external additive has a chain shape of 6 to 500 fine particles. Or, a toner for developing an electrostatic latent image, wherein the toner is an inorganic particle having a branched shape and the bond being a covalent bond. 2. The method according to claim 1, wherein the inorganic particles have a particle size of not less than 5 nm and not more than 10 nm.
30 nm or more and 800 nm or less when 0 nm or less
2. The electrostatic latent image developing toner according to claim 1, wherein the toner has the following particle diameter and is subjected to a hydrophobic treatment. 3. The method according to claim 1, wherein the inorganic particles have a particle size of not less than 8 nm and not more than 60 nm.
3. The toner for developing an electrostatic latent image according to claim 2, wherein the particles having a particle size of not more than nm have a particle diameter of not less than 80 nm and not more than 500 nm. 4. The toner according to claim 1, wherein the colored particles are toner having a ratio of particles having no corners of 50% by number or more and a number variation coefficient in a number particle size distribution of 27% or less. The toner for developing an electrostatic latent image according to claim 1. 5. The colored particles have a shape factor of 1.2 to 1.2.
5. The static particles according to claim 1, wherein the ratio of particles in the range of 1.6 is 65% by number or more and the variation coefficient of the shape coefficient is 16% or less. 6. Electrostatic latent image developing toner. 6. The electrostatic latent device according to claim 1, wherein the colored particles are resin particles obtained by polymerizing at least a polymerizable monomer in an aqueous medium. Image developing toner. 7. The electrostatic latent image developing device according to claim 1, wherein the colored particles are obtained by aggregating and fusing at least resin particles in an aqueous medium. toner. 8. A BET specific surface area of 1.1 to 4.0 m ² /
g, the surface abundance of silicon atoms measured by ESCA is 6 to
The electrostatic latent image developing toner according to any one of claims 1 to 7, wherein 12 area% and the amount of carbon atoms present are 50 to 75 area%. 9. An image forming method employing a toner recycling system, wherein the toner for developing an electrostatic latent image according to claim 1 is used. 10. An image forming method employing a non-magnetic one-component developing method, wherein the toner for developing an electrostatic latent image according to claim 1 is used. 11. An image forming apparatus employing a toner recycling system, wherein the toner for developing an electrostatic latent image according to claim 1 is used. 12. An image forming apparatus employing a non-magnetic one-component developing method, wherein the toner for developing an electrostatic latent image according to claim 1 is used.