JP2002278164A - Electrophotographic toner, developer and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic toner ensuring a stable quantity of electric charges of the toner and a stable amount of the toner conveyed and giving high quality images even when used over a long period of time. SOLUTION: In the electrophotographic toner comprising a bonding resin, a colorant, an electrostatic charge controlling agent and additives, a polyester and/or a polyol is used as the bonding resin, a plastic electrostatic charge controlling agent having at least a sulfonic acid-containing monomer, an aromatic monomer having an electron withdrawing group and an acrylic ester and/or methacrylic ester monomer as constitutional units and containing repeating units of those monomers by 1-30 wt.%, 1-80 wt.% and 10-80 wt.%, respectively, based on the weight of the plastic electrostatic charge controlling agent is used as the electrostatic charge controlling agent and (I) silica made hydrophobic by treatment and having 0.01-0.03 μm primary particle diameter, (II) titanium oxide made hydrophobic by treatment and having 0.01-0.03 μm primary particle diameter and 60-140 m<2> /g specific surface area and (III) silica made hydrophobic by treatment and having 20-50 m<2> /g specific surface area and 100-250 g/l bulk density are used as the additives.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used as a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, and an image forming method using the toner. More specifically, an external additive for an electrophotographic toner, an electrophotographic toner, an electrophotographic developer, and an image forming apparatus used in a copier, a laser printer, a plain paper fax, etc. using a direct or indirect electrophotographic developing method. About. Furthermore, the present invention relates to an electrophotographic toner, an electrophotographic developer, and an image forming method used for a full-color copying machine, a full-color laser printer, a full-color plain paper facsimile, and the like using a direct or indirect electrophotographic multicolor image developing system.

[0002]

2. Description of the Related Art A developer used in electrophotography, electrostatic recording, electrostatic printing and the like is once adhered to an image carrier such as a photoconductor on which an electrostatic image is formed in a developing process. Then, after being transferred from the photoreceptor to a transfer medium such as transfer paper in a transfer step, it is fixed on the paper surface in a fixing step. At this time, as a developer for developing an electrostatic image formed on the latent image holding surface, a two-component developer composed of a carrier and a toner and a one-component developer that does not require a carrier (magnetic toner or Non-magnetic toner) is known. In the two-component developing method, the developer deteriorates due to the toner particles adhering to the carrier surface, and the toner concentration in the developer decreases because only the toner is consumed.
The mixing ratio with the carrier must be maintained at a constant ratio, which causes a disadvantage that the developing device becomes large. On the other hand, the one-component developing method has no such drawbacks and has advantages such as downsizing of the apparatus, so that the developing method is becoming mainstream.

In recent years, office automation (OA) and color printing have been further advanced in offices. In addition to the conventional method of copying originals consisting of only characters, originals including graphs and the like created by a personal computer are output by a printer. ,
Opportunities to copy a large number of documents as presentation materials are increasing. The printer output image is a solid image,
There are many line images and halftone images, and the market demands for image quality are changing accordingly,
Demands for high reliability and the like are increasing.

Electrophotographic processes using a one-component developer are classified into a magnetic one-component developing system using a magnetic toner and a non-magnetic one-component developing system using a non-magnetic toner.
The magnetic one-component developing method uses a developer carrier provided with a magnetic field generating means such as a magnet inside, holds a magnetic toner containing a magnetic substance such as magnetite, and develops a thin layer by a layer thickness regulating member. In recent years, a large number of printers have been put to practical use. On the other hand, in the non-magnetic one-component developing method, since the toner does not have a magnetic force, a toner supply roller is pressed against the developer carrier to supply the toner onto the developer carrier and electrostatically hold the toner. Then, the layer is thinned and developed by the layer thickness regulating member. The non-magnetic one-component developing method has an advantage that it can cope with colorization because it does not contain a colored magnetic material.In addition, since a magnet is not used for the developer carrier, it is possible to reduce the weight and cost, In recent years, it has begun to be used in small full-color printers.

However, at present, there are still many problems to be improved in the one-component developing system. In the two-component developing method, a carrier is used as a toner charging and conveying means,
After the toner and the carrier are sufficiently stirred and mixed in the developing device, the toner and the carrier are transported to the developer carrier and developed.
Even when used for a relatively long time, stable charging and conveyance can be maintained, and it is easy to cope with a high-speed developing device.

On the other hand, in the one-component developing method, since there is no stable charging and transporting means such as a carrier, charging failure or transport failure due to long-time use or high speed is likely to occur. In the one-component developing method, the toner is conveyed onto the developer carrying member, and then the toner is thinned by a layer thickness regulating member to develop the toner. Since the contact and frictional charging time with the toner is extremely short, the amount of low-charge and reverse-charge toner tends to increase more than in the two-component developing method using a carrier. In particular, in a non-magnetic one-component developing method, a means for conveying toner (developer) by at least one toner conveying member and developing an electrostatic latent image formed on a latent image carrier by the conveyed toner is usually used. However, at that time, the thickness of the toner layer on the surface of the toner conveying member must be reduced as much as possible. This is true even when a two-component developer having a very small carrier diameter is used.
In particular, when a one-component developer is used and a toner having a high electric resistance is used, it is necessary to charge the toner by a developing device. Therefore, the layer thickness of the toner must be extremely thin. This is because if the toner layer is thick, only the vicinity of the surface of the toner layer is charged, and it is difficult to uniformly charge the entire toner layer. For this reason, the toner is required to maintain a more rapid charging speed and an appropriate charging amount.

Conventionally, a charge controlling agent has been added to stabilize the charge of the toner. The charge control agent functions to control the frictional charge amount of the toner and maintain the frictional charge amount. Typical examples of the negatively chargeable charge control agent include monoazo dyes, salicylic acid, naphthoic acid, metal salts and complex salts of dicarboxylic acids, diazo compounds, and complex compounds with boron. Examples of the control agent include a quaternary ammonium salt compound, an imidazole compound, nigrosine, and an azine dye. However, since these charge control agents are colored, there is a problem that the hue changes when used in a color toner. In addition, since such a charge controlling agent has poor compatibility with the binder resin, those present on the surface of the toner, which are greatly involved in the charging, are likely to be detached, causing variations in the charging of the toner, the development sleeve, and the photosensitive drum. There are drawbacks such as body filming that easily contaminates. Therefore, in the related art, a good image can be obtained in the initial stage, but the image quality gradually changes, and a phenomenon occurs in which the background becomes dirty and the image is blurred. In particular, when applied to color copying and used continuously while replenishing the toner, the charge amount of the toner decreases, and the color tone of the initially copied image becomes significantly different from that of the initial copied image. There is a disadvantage that the image forming unit called a process cartridge needs to be replaced at an early stage with about 1,000 sheets. For this reason, the burden on the environment is large and the user has to take time. Further, since many of these charge control agents contain heavy metals such as chromium, they have recently become a problem from the viewpoint of safety.

To solve the above problems, Japanese Patent Application Laid-Open Nos. 63-88564, 63-184762, 3-56974, and 6-230609 disclose compatibility of a binder resin. A resin charge control agent having improved transparency and safety of a toner-fixed image is disclosed. Since these resin charge control agents have good compatibility with the binder resin, they are excellent in stable chargeability and transparency. But,
These resin charge control agents have the disadvantage that the charge amount and the charge speed are inferior to toners using monoazo dyes, metal salts and complex salts of salicylic acid, naphthoic acid and dicarboxylic acid. In addition, although the chargeability is improved by increasing the amount of the resin charge control agent added, the toner fixability (low-temperature fixability, anti-offset property) is adversely affected. Further, these compounds have high environmental stability (humidity resistance) of the charge amount. For this reason, there is also a problem that background soiling (fogging) easily occurs.

Further, Japanese Patent Application Laid-Open Nos.
171271, JP-A-9-212896, JP-A-11-
In 218965, a copolymer of a monomer containing an organic acid salt such as a sulfonic acid group and an aromatic monomer having an electron-withdrawing group is proposed. However, due to the hygroscopicity and adhesiveness, which are considered to be caused by the monomer containing an organic acid salt such as a sulfonic acid group, a sufficient amount of charge is secured, but the dispersion in the binder resin is not sufficient, and the toner is not used for a long time. The effect of suppressing the variation in the charging of the toner and preventing the filming of the developing sleeve and the photoconductor is not sufficient. Furthermore, in the productivity of the toner pulverization method, metal salts and metal complex salts of monoazo dyes, salicylic acid, naphthoic acid, and dicarboxylic acid are used as charge control agents. There was also an adverse effect of lower productivity than when used.

In order to improve the compatibility with a styrene resin or a polyester resin as a binder resin, a monomer containing an organic acid salt such as a sulfonic acid group, an aromatic monomer having an electron withdrawing group, and a styrene resin are used. A copolymer with a monomer or a polyester-based monomer has been proposed, but the effect of maintaining the charge amount for a long period of time and preventing the developing sleeve and the photoconductor from filming is insufficient. In particular, as a binder resin for a full-color toner, it is still insufficient to use a polyester resin or a polyol resin suitable for color development and image strength. By adding a sulfonic acid group-containing monomer as a monomer constituting the resin charge control agent, the effect of imparting a negative charge to the resin charge control agent is improved.
Since the environmental stability (temperature / humidity stability) of the toner is reduced due to the hygroscopicity, it is generally known that the toner is used as a copolymer with an aromatic monomer having an electron withdrawing group. However, the use of several thousand sheets is sufficient, but the long-term use of tens of thousands of sheets causes contamination of the developing sleeve and the layer thickness regulating members (blades and rollers) and filming of the photoconductor.
Insufficient maintenance of toner charging stability and high image quality,
There is a problem that productivity also decreases.

In recent years, the demand for printers has been expanding, and the miniaturization, high speed, and low cost of the devices have been progressing, and higher reliability and longer life have been required for the devices. However, these resin charge control agents cannot maintain the charge control effect, and the developing sleeve and layer thickness regulating members (blades and rollers)
And the toner has poor charging performance and filming of the photoreceptor.

JP-A-5-53369 discloses an inorganic material treated with a coupling agent having a BET specific surface area of 1 to 150 m ² / g and having a saturated or unsaturated cyclic or acyclic organic group having 5 or more carbon atoms. Fine powder and BET specific surface area of 160
A toner having an inorganic fine powder having a hydrophobicity of 30 or more at 400 m ² / g is disclosed. However, the charging characteristic of the toner on the developing sleeve becomes unstable, and the toner spills or scatters from the developing sleeve. There is a point.

Further, Japanese Patent Application Laid-Open No. Hei 6-202374 discloses a non-magnetic one-component toner in which inorganic fine particles having an average particle diameter of 30 nm or more and less than 100 nm are attached, but the fluidity of the toner is insufficient. There is a problem that the replenishing ability of the car becomes insufficient.

JP-A-8-15890 discloses toner particles having an average particle size of 4 to 9 μm and a small particle size (7 to 20 nm).
And a one-component developer comprising an external additive having a large particle diameter (20 to 80 nm) and having a small particle diameter of 1 to 2% by weight, but the charging characteristic of the toner on the developing sleeve is unstable. Thus, there is a problem that the toner is spilled or scattered from the developing sleeve.

Japanese Patent Application Laid-Open No. 9-288369 discloses a BET specific surface area of 20 to 50 m ² / g, a pH of 6 to 8, and a hydrophobicity of 85%.
Although the toner containing the above silica fine particles is disclosed, there is a problem that the fluidity of the toner is not sufficient and the toner replenishing property is insufficient.

[0016]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a resin charge control agent having excellent compatibility with a binder resin, transparency of a toner-fixed image, and excellent safety. The purpose is to solve the problem. That is, an object of the present invention is to provide an electrophotographic toner, a developer, and an image forming method that can stably charge and transport a toner even when used for a long period of time and obtain high image quality with high image density and less background contamination. Is to provide a way. Further, the present invention is particularly applicable to a one-component developing system in which a thin layer of toner is formed on a toner conveying member (development sleeve) by a layer thickness regulating member to perform development, and a toner thin layer is formed on the toner conveying member (developing sleeve) Toner for electrophotography that has good properties (thin toner layer thickness of several toner particles), no change in chargeability of toner after continuous printing, and tens of thousands or more of image quality equivalent to the initial image can be obtained. It is an object to provide an agent and an image forming method.

Another object of the present invention is to provide a toner for electrophotography which prevents contamination of a developing sleeve and a layer thickness regulating member (a blade or a roller) and tens of thousands of photoreceptor filming in a long-term use. And an image forming method.

Still another object of the present invention is to provide an electrophotographic toner, a developer, and an image forming method, which cause less toner scattering in a developing machine even during long-term use.

Another object of the present invention is to enable the developing unit and the photosensitive unit to be used for a long period of time,
An object of the present invention is to provide an electrophotographic toner, a developer, and an image forming method that reduce the burden on the environment and reduce the user's labor for replacement.

Another object of the present invention is to provide an electrophotographic toner having good color reproducibility by using a colorless or light-colored resin charge control agent.

Still another object of the present invention is to provide a method obtained from a production step of kneading, pulverizing and classifying a toner, in which there is no sticking in a pulverizing step, a large amount of pulverization processing per unit time without excessive pulverization. An object of the present invention is to provide a highly productive electrophotographic toner.

[0022]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have paid close attention to the components and composition ratio of the resin charge control agent and the configuration of the external additive of the toner. When a resin charge control agent and a toner external additive having a specific composition ratio and a specific composition ratio are used for a polyester resin or a polyol resin which is suitable in terms of color development and image strength as a binder resin for use, a high value is obtained. The charge amount and the sharp charge distribution are obtained, and the toner thin layer formation property on the developing sleeve is good for more than tens of thousands of sheets, and the contamination of the developing sleeve and the layer thickness regulating members (blades and rollers) and the photoreceptor filming are prevented. It has been found that a toner, a developer and an image forming method for electrophotography which can be prevented and have good pulverizability and high productivity can be obtained.

That is, the present invention comprises the following aspects. (1) In an electrophotographic toner comprising at least a binder resin and a colorant, the binder resin is a polyester and / or a polyol, the electrophotographic toner further contains a charge control agent, and the charge control agent is A resin charge control agent having at least a sulfonic acid group-containing monomer as a monomer, an aromatic monomer having an electron withdrawing group, and an acrylic acid ester and / or methacrylic acid ester monomer as constituent units. The repeating unit is 1 to 30% by weight based on the weight of the resin charge control agent, the repeating unit of the aromatic monomer having the electron-withdrawing group is 1 to 80% by weight based on the weight of the resin charge control agent, the acrylate ester and / or The repeating unit of methacrylic acid ester monomer is contained in a ratio of 10 to 80% by weight based on the weight of the resin charge control agent. An electrophotographic toner, wherein the toner for electrophotography further contains an external additive, and the following external additives (I), (II) and (III). (I) Hydrophobized silica having a primary particle size of 0.01 to 0.03 μm. (II) Hydrophobized titanium oxide having a primary particle size of 0.01 to 0.03 μm and a specific surface area of 60 to 140 m ² / g. (III) Specific surface area 20-50 m ² / g, bulk density 100
~ 250 g / l of hydrophobized silica. (2) The electron according to (1), wherein the aromatic monomer having an electron-withdrawing group is a phenylmaleimide-substituted or phenylitaconimide-substituted substituted with a chlorine atom or a nitro group. Photo toner. (3) The above-mentioned (1) or (2), wherein the temperature at which the apparent viscosity of the resin charge control agent by a flow tester becomes 10 ⁴ P (10 ⁴ g / cm · s) is 85 to 110 ° C. 2. The electrophotographic toner according to item 1. (4) The number average molecular weight of the resin charge control agent is 1000
(1) to (1), wherein
The electrophotographic toner according to any one of (3). (5) The resin charge control agent is added to the toner particles in an amount of 0.
(1) to (1) to (10) above, wherein
The electrophotographic toner according to any one of (4). (6) The electrophotographic toner according to any one of (1) to (5), wherein the binder resin has an acid value of 20 KOH mg / g or less. (7) The external additives (I) to (III) are each 0.1 to 1.5 parts by weight of (I) and 0.1 to 1 part by weight (II) with respect to 100 parts by weight of the base toner. 0.5 parts by weight, 0.3 of (III)
(1) to (2) above, wherein
The electrophotographic toner according to any one of (6). (8) A two-component developer using the electrophotographic toner according to any one of (1) to (7), wherein the carrier is a silicon-coated carrier. (9) a latent image forming step of forming a latent image on the latent image holding member,
An image having a development step of developing the latent image using a developer on a developer carrier, a transfer step of transferring the developed toner image onto a transfer body, and a fixing step of heating and fixing the toner image on the transfer body In the forming method, the developer may be any of the above (1) to (7)
An image forming method, which is a one-component developer using the electrophotographic toner according to any one of the above. (10) The image forming method according to the above (9), wherein the developing step includes forming a thin layer of the developer on the developer carrying member and performing development with or without contacting the latent image holding member. . (11) Dividing the layer thickness of the developing roll and the developer supplied onto the developing roll into multiple colors formed on the electrostatic image carrier by a plurality of multicolor developing devices having uniform layer thickness regulating members. The developed electrostatic latent images are developed on a plurality of electrostatic image carriers corresponding to the respective colors by the developers corresponding to the respective colors, and transfer means is applied to the surface of the electrostatic image carriers via a transfer material. In the electrophotographic developing method used in an electrophotographic recording apparatus for bringing an electrostatic transfer of the toner image into the transfer material in contact with the electrophotographic toner, the electrophotographic toner according to any one of the above (1) to (7) is used. An image forming method using a one-component developer.

Hereinafter, the present invention will be described in detail. In the electrophotographic toner of the present invention, the binder resin is a polyester and / or a polyol, and the charge control agent is a monomer containing at least a sulfonic acid group-containing monomer, an aromatic monomer having an electron withdrawing group, and an acrylate and / or methacrylic acid. An electrophotographic toner which is a resin charge control agent having an acid ester monomer as a structural unit.

The sulfonic acid group-containing monomers constituting the resin charge control agent used in the present invention include aromatic sulfonic acid group-containing monomers and aliphatic sulfonic acid group-containing monomers. As the aromatic sulfonic acid group-containing monomer, vinyl sulfonic acid, allyl vinyl sulfonic acid,
Examples thereof include alkali metal salts such as 2-acrylamido-2-methylpropanesulfonic acid and methacryloyloxyethylsulfonic acid, alkaline earth metal salts, amine salts and quaternary ammonium salts. Examples of the aliphatic sulfonic acid group-containing monomer include alkali metal salts such as styrenesulfonic acid, sulfophenylacrylamide, sulfophenylmaleimide, and sulfophenylitaconimide, alkaline earth metal salts, amine salts, and quaternary ammonium salts. . Salts of heavy metals (nickel, copper, zinc, mercury, chromium, etc.) are not preferred in terms of safety.

The aromatic monomer having an electron-withdrawing group constituting the resin charge controlling agent used in the present invention includes styrene-substituted products such as chlorostyrene, dichlorostyrene, bromostyrene, fluorostyrene, nitrostyrene, and cyanostyrene; (Meth) acrylate,
Substituted phenyl (meth) acrylate such as bromophenyl (meth) acrylate, nitrophenyl (meth) acrylate, chlorophenyloxyethyl (meth) acrylate, chlorophenyl (meth) acrylamide, bromophenyl (meth) acrylamide, nitrophenyl (meth) acrylamide Substituted phenyl (meth) acrylamides such as phenylphenylmaleimide, dichlorophenylmaleimide, nitrophenylmaleimide, nitrochlorophenylmaleimide and the like; phenyls such as chlorophenylitaconimide, dichlorophenylitaconimide, nitrophenylitaconimide and nitrochlorophenylitaconimide Substituted itaconimide, chlorophenyl vinyl ether, nitrophenyl vinyl ether Phenyl vinyl ether substituents such as Le, and the like. In particular, substituted phenylmaleimide and substituted phenylitaconimide substituted with a chlorine atom or a nitro group are preferable in terms of charging properties and filming resistance.

The acrylate and / or methacrylate monomers constituting the resin charge control agent used in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and the like.
Examples thereof include n-butyl (meth) acrylate, isobutyl (meth) acrylate, stearyl (meth) acrylate, dodecyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate.

As described in the section of the prior art, it is known that an aromatic monomer having an electron withdrawing group is added to a sulfonic acid group-containing monomer to be used as a copolymer.
There have been several problems typified by charging stability during long-term use. In order to compensate for such a drawback, in the present invention, a sulfonic acid group-containing monomer and an aromatic monomer having an electron-withdrawing group are used as a binder resin for a full-color toner, with respect to a polyester resin or a polyol resin which is suitable in terms of color development and image strength. And a copolymer containing three kinds of monomers of acrylic acid ester and / or methacrylic acid ester is used as a resin charge control agent. As a result, the charging and environmental stability are excellent over a long period of time, the developing sleeve and the layer thickness regulating members (blades and rollers) are not contaminated, the thin layer is formed well, the photoreceptor filming is prevented, and high image quality is maintained. Thus, an electrophotographic toner having high productivity can be obtained.

The effect of the charge control agent is presumed to be due to the following reasons. That is, by using a sulfonic acid group-containing monomer and an aromatic monomer having an electron-withdrawing group in combination, the effect of imparting negative charge is enhanced, and by using an acrylate and / or methacrylate monomer, the environmental stability of charging is further improved. The resin hardness increases as well as the pulverizability, and the pulverizability improves. At the same time, developing sleeves and layer thickness regulating members (blades and rollers)
And the effect of preventing photoreceptor filming is improved. Further, by combining with a polyester resin or a polyol resin which is suitable in terms of color development and image strength as a binder resin for a full-color toner, an appropriate dispersibility can be obtained and an electrophotographic toner having a sharp charge distribution can be obtained.

The composition ratio of the monomers in the resin charge control agent of the present invention is such that the sulfonic acid group-containing monomer is 1 to 30% by weight, more preferably 2 to 20% by weight. When the amount of the sulfonic acid group-containing monomer is less than 1% by weight, the rise of charge and the amount of charge are not sufficient, and the image is likely to be affected.
If the content exceeds 30% by weight, the environmental stability of charging deteriorates.
The charge amount at high temperature and high humidity is low, and the charge amount at low temperature and low humidity is high, and the charge stability and high image quality of the toner are not sufficiently maintained. Further, there is a problem that contamination of the developing sleeve and the layer thickness regulating member (blade and roller) and filming of the photoreceptor are apt to occur, and the productivity at the time of toner production by the kneading / pulverizing method is lowered.

The constituent ratio of the aromatic monomer having an electron withdrawing group is from 1 to 80% by weight, more preferably from 20 to 70% by weight. When the amount of the aromatic monomer having an electron-withdrawing group is less than 1% by weight, the charge amount is not sufficient, and background contamination and toner scattering are likely to occur. On the other hand, if it exceeds 80% by weight, the dispersion in the toner is poor, the charge distribution of the toner is widened, the background smear and the toner are easily scattered, and the maintenance of high image quality is not sufficient.

The constituent ratio of the acrylate and / or methacrylate monomers is 10 to 80% by weight, more preferably 20 to 70% by weight. 10% by weight of acrylate and / or methacrylate monomer
If it is less than 3, sufficient environmental stability of charging cannot be obtained, the pulverizability at the time of toner production by the kneading / pulverization method is not sufficient, and the developing sleeve and layer thickness regulating members (blades and rollers) are contaminated. Also, filming of the photoconductor cannot be sufficiently prevented. If it exceeds 80% by weight, the rise of the charge and the amount of charge are not sufficient, and the image is likely to be affected.

The resin charge control agents of these combinations have appropriate dispersibility and chargeability by combining with a polyester resin or a polyol resin which is suitable in terms of color development and image strength as a binder resin for full-color toner. An electrophotographic toner having a sharp distribution can be obtained. If this toner is used for image formation, long-term charging stability and high image quality can be obtained.

The resin charge controlling agent used in the electrophotographic toner of the present invention has an apparent viscosity of 10 ⁴ by a flow tester.
The temperature at which P (= 10 ⁴ g / cm · s) is 85 to 110
C. is preferred. When the temperature is lower than 85 ° C., appropriate dispersibility in the toner cannot be obtained, and not only does the charge decrease, but also in the method obtained from the kneading, pulverizing / classifying production process, sticking in the pulverizing process is likely to occur. Degrades productivity. On the other hand, when the temperature exceeds 110 ° C., the dispersibility in the toner is reduced, the charge distribution is widened, and the background is easily scattered and the toner is scattered in the machine. Further, the fixability of the toner, particularly the color developability at the time of color mixing of the color toner, becomes poor. The temperature at which the apparent viscosity becomes 10 ⁴ P (10 ⁴ g / cm · s) is measured using a flow tester at a load of 10 kg / cm ² , an orifice of 1 mm × 1 mm, and a heating rate of 5 ° C./min. Is 10 ⁴ P (10 ⁴ g / cm · s). Shimadzu Corporation CFT-500 type can be used as the flow tester.

The number average molecular weight of the resin charge control agent of the present invention is preferably 1,000 to 100,000. If it is less than 1000, appropriate dispersibility in the toner cannot be obtained, and not only does the charge decrease, but also kneading, pulverization,
In the method obtained from the production step of classifying, sticking in the pulverization step is likely to occur, thereby deteriorating productivity. Also, 10
When it exceeds 0000, the dispersibility in the toner is reduced, the charge distribution is widened, the toner is liable to be scummed in the image forming apparatus, and the fixing property and the color developing property of the toner are poor.

The amount of the resin charge control agent of the present invention is preferably 0.1 to 20% by weight based on the toner particles.
5 to 10% by weight is more preferred. If the amount is less than 0.1% by weight, the rising of the charge and the amount of charge are not sufficient, and the image is likely to be affected. If it exceeds 20% by weight, the dispersion will be poor, the charge distribution will be wide, and the background will be soiled and the toner will scatter in the machine. Further, as the charge control agent, at least one selected from the group consisting of a chromium complex or salt of salicylic acid and a chromium complex or salt of alkyl salicylic acid.
Seeds may be used in combination.

As the binder resin used in the present invention, a polyester resin or a polyol resin which is suitable as a binder resin for a full-color toner in terms of color development and image strength is used.
In a color image, several types of toner layers are superimposed one upon another, so that the toner layer becomes thick, and the image may be cracked or defective due to insufficient strength of the toner layer, or moderate gloss may be lost. For this reason, a polyester resin or a polyol resin is used to maintain appropriate gloss and excellent strength.

The polyester resin used for the binder resin can be generally obtained by an esterification reaction between a polyhydric alcohol and a polycarboxylic acid. Among the monomers constituting the polyester resin in the present invention, examples of the alcohol monomer including tri- or higher-valent polyfunctional monomers include ethylene glycol, diethylene glycol triethylene glycol, 1,2-propylene glycol, and 1,3-propylene. Glycols such as glycol, 1,4-butadieneol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, polyoxypropylene Bisphenol A alkylene oxide adducts such as bisphenol A, other dihydric alcohols, or sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol , Tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane , Trimethylolpropane, 1,3
Examples thereof include 5-trihydroxybenzene and other trihydric or higher polyhydric alcohols.

Among the monomers constituting the polyester resin, those using a bisphenol A alkylene oxide adduct as a main component monomer are particularly preferably used. When a bisphenol A alkylene oxide adduct is used as a constituent monomer, a polyester having a relatively high glass transition point can be obtained due to the nature of the bisphenol A skeleton, and copy blocking resistance and heat storage stability are good. Also, the presence of alkyl groups on both sides of the bisphenol A skeleton acts as a soft segment in the polymer,
The color developability and image strength at the time of fixing the toner are improved. In particular, among the bisphenol A alkylene oxide adducts, those having an ethylene group or a propylene group are preferably used.

Among the monomers constituting the polyester resin in the present invention, examples of the acid monomer, including tri- or higher valent polyfunctional monomers, include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, Isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, or n-dodecenyl succinic acid, n-
Alkenyl succinic acids or alkyl succinic acids such as dodecyl succinic acid, anhydrides, alkyl esters of these acids, other divalent carboxylic acids, and 1,2,4
-Benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,2
4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid And empole trimer acids, and their anhydrides, alkyl esters, alkenyl esters, aryl esters, and other trivalent or higher carboxylic acids.

Specific examples of the alkyl group, alkenyl group or aryl ester described herein include 1, 2, 4
-Benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid trimethyl, 1,2,4-benzenetricarboxylic acid triethyl, 1,2,4-benzenetricarboxylic acid tri-n-butyl, 1,2,4-benzenetricarboxylic acid Isobutyl, tri-n-octyl 1,2,4-benzenetricarboxylate, tri-2-ethylhexyl 1,2,4-benzenetricarboxylate, tribenzyl 1,2,4-benzenetricarboxylate, 1,2,4-benzenetricarboxylic acid Tris (4-isopropylbenzyl) and the like can be mentioned.

It is known that the relationship between the chargeability of a polyester resin and the acid value is almost proportional to each other. It is known that the higher the acid value, the greater the negative chargeability of the resin. Also affect. That is, when the acid value is high, the charge amount becomes high under low temperature and low humidity, and the charge amount becomes low under high temperature and high humidity, the background stain, the image density, the change in color reproducibility become large, and it is difficult to maintain high image quality. . Accordingly, the acid value of the polyester resin is preferably 20 KOH mg / g or less, and more preferably 5 KOH mg / g or less.

The polyol resin used as the binder resin in the present invention includes epoxy resin terminals from the viewpoint of environmental stability of charging, fixing stability, color reproducibility, gloss stability, curling prevention after fixing, and the like. Are preferred and have a polyoxyalkylene moiety in the main chain.
For example, it can be obtained by reacting an epoxy resin having both terminal glycidyl groups and an alkylene oxide adduct of a dihydric phenol having both terminal glycidyl groups with dihalide, isocyanate, diamine, diol, polyhydric phenol, or dicarboxylic acid. Of these, the reaction with a dihydric phenol is most preferable in terms of reaction stability. It is also preferable to use a polyhydric phenol or a polycarboxylic acid together with a dihydric phenol within a range not causing gelation.

The following are examples of the alkylene oxide adduct of a dihydric phenol having a glycidyl group at both terminals used in the present invention. Examples include ethylene oxide, propylene oxide, butylene oxide, and reaction products of these mixtures with bisphenols such as bisphenol A and bisphenol F. The obtained adduct is
It may be used after glycidylation with epichlorohydrin or β-methylepichlorohydrin. In particular, a glycidyl ether of an alkylene oxide adduct of bisphenol A represented by the following general formula (1) is preferable.

Embedded image In the above formula (1), R represents —CH ₂ —CH ₂ —, —CH ₂ —
CH (CH ₃ ) — or —CH ₂ —CH ₂ —CH ₂ —, and n and m are the number of repeating units, each of which is 1
As described above, n + m = 2 to 6.

The following three types of external additives can be used in the present invention. (I) Hydrophobized silica having a primary particle size of 0.01 to 0.03 μm. (II) a primary particle size of 0.01 to 0.03 μm and a specific surface area of 6
0 to 140 m ² / g of hydrophobically treated titanium oxide. (III) Specific surface area 20-50 m ² / g, bulk density 100-2
50 g / l of hydrophobized silica.

By attaching the hydrophobically treated silica (I) having a primary particle size of 0.01 to 0.03 μm to the surface of the toner, necessary fluidity and chargeability are imparted to the toner, and In addition, the developability from the developing sleeve to the photoconductor is improved. The addition amount of this type of silica is preferably 0.1 to 1.5 parts by weight based on 100 parts by weight of the base toner. If the amount is less than this, the necessary amount of toner is supplied to the developing sleeve. Or the required amount of toner charge may not be obtained. If the amount is larger than the above range, the chargeability of the toner may be too high to sufficiently develop the toner or the toner may be scattered from the developing sleeve.

The primary particle size is 0.01 to 0.03 μm
The hydrophobicized titanium oxide (II) having a specific surface area of 60 to 140 m ² / g with respect to 100 parts by weight of the base toner,
By attaching the toner to the surface of the toner in an amount of 0.1 to 1.5 parts by weight, the chargeability of the toner is stabilized, and in particular, the charge rising property and the charge-up are prevented. If the amount of this type of titanium oxide is less than this, the toner may not be sufficiently developed due to too high chargeability of the toner.
If the amount is larger than the above range, the chargeability of the toner is too low, and the toner may be scattered from the developing sleeve or the background may be stained.

Further, hydrophobically treated silica (II) having a specific surface area of 20 to 50 m ² / g and a bulk density of 100 to 250 g / l
I) was added in an amount of from 0.3 to 2. based on 100 parts by weight of the base toner.
By attaching the toner to the surface of the toner at 0 parts by weight, the thin layer of the toner on the developing sleeve becomes uniform, the unevenness of the thin layer is greatly improved, and the rotation of the developing sleeve for a long period of time causes the layer thickness regulating member (blade And the occurrence of white stripes due to the fusion of the toner to the roller. If the amount of silica of this type is smaller than this, the thin layer of the toner on the developing sleeve becomes non-uniform, and uniform development of the toner and an image cannot be obtained. White streaks may occur due to fusion of toner to blades and rollers. When added in excess, silica of this type may be present in excess and not adhered to the surface of the toner, thus impairing the charging stability of the toner.

The two types of silica used in the present invention are generally produced by a wet method or a dry method, and in particular, a so-called fume produced by a dry method (vapor phase oxidation of a silicon halide compound). What is called silica is preferable from the viewpoint of fluidity.

The volume average particle size of the toner particles is 4 to 9
μm, the ratio of the volume average diameter Dv to the number average diameter Dn, D
When v / Dn is 1.5 or less, an image obtained after long-term use has a small difference from the initial image quality.

When the toner of the present invention is used in a two-component developer in which a carrier is mixed, the same effect as in a one-component developer containing only the toner can be obtained. When using the toner of the present invention as a two-component developer, as the carrier, an acrylic resin,
A carrier using a coating agent such as a fluororesin or a silicone resin can be used. Among them, a silicon-coated carrier is superior from the viewpoint of the life of the developer.

According to the second aspect of the present invention, a latent image forming step of forming a latent image on a latent image holding member, a developing step of developing the latent image using a developer on a developer carrier, One-component developer using the electrophotographic toner of the present invention as a developer in a method of forming an image having a transfer step of transferring a toner image onto a transfer body and a fixing step of heating and fixing the toner image on the transfer body. And an image forming method using the method.

Further, in the above-described image forming method, the developing step includes forming a thin layer of the developer on the developer carrier and developing it with or without contact with the latent image holding member. A method is provided.

Further, according to another aspect of the present invention, a plurality of multi-layers each including a developing roll and a layer thickness regulating member (blade or roller) for uniformly regulating the layer thickness of the developer supplied onto the developing roll. The multicolored electrostatic latent image formed on the electrostatic image carrier is formed on the electrostatic image carrier by a color developing device using a developer corresponding to each color on a plurality of electrostatic image carriers corresponding to each color. In the image forming method used in the electrophotographic recording apparatus, the toner image is sequentially electrostatically transferred to the transfer material by bringing a transfer unit into contact with the surface of the electrostatic image carrier through a transfer material. An image forming method characterized by using a one-component developer using an electrophotographic toner is provided.

As the colorant used in the electrophotographic toner of the present invention, any of the following known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, hansa yellow (10G,
5G, G), cadmium yellow, yellow iron oxide, loess, graphite, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Tan, Lead Zhu, Cadmium Red, Cad Muum Mercury Red, Antimony Vermilion,
Permanent Red 4R, Para Red, Phisay Red, Para Chlor Ortho Nitroaniline Red, Lysole Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine Min BS, Permanent Red (F2R, F4R, FRL, FRLL, F4R
H), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Lisor Rubin G
X, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin rake,
Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC),
Indigo, ultramarine, navy blue, anthraquinone blue, fast violet B, methyl violet lake, cobalt violet, manganese violet, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B , Green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, lithobon, and mixtures thereof. The amount used is generally 0.1 to 50 parts by weight based on 100 parts by weight of the binder resin.

When the toner of the present invention is used as a developer, it is preferable that a wax is contained in the produced developer in order to give the developer a releasing property. The wax has a melting point of 40 to 120 ° C., preferably 50 to 110 ° C. When the melting point of the wax is too high, the fixability at low temperatures may be insufficient, while when the melting point is too low, the offset resistance and durability may decrease. The melting point of the wax is determined by a differential scanning calorimetry ( DSC). That is, the melting peak value when a few mg of the sample is ripened at a constant heating rate, for example (10 ° C./min), is defined as the melting point.

Examples of the wax that can be used in the present invention include solid paraffin wax, micro wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketones, fatty acid metal salt wax, and fatty acid ester wax. And partially saponified fatty acid ester waxes, silicone varnishes, higher alcohols, and carnauba wax. Polyolefins such as low molecular weight polyethylene and polypropylene can also be used. In particular, a polyolefin having a softening point of 70 to 150 ° C by a ring and ball method is preferable,
Further, a polyolefin having a softening point of 120 to 150 ° C is preferable.

The method for producing an electrophotographic toner according to the present invention comprises:
A step of mechanically mixing a toner component containing a binder resin, a charge controlling agent, a colorant and an external additive as constituent materials, a step of melt-kneading, a step of pulverizing, and a step of classifying. Manufacturing methods can be applied. Further, in the step of mechanically mixing and the step of melt-kneading, a production method in which powder other than the particles serving as a product obtained in the pulverization or classification step is returned and reused is also included.

The powder (by-product) other than the particles to be a product referred to here is subjected to the step of melt-kneading, followed by fine particles and coarse particles other than the components to be a product having a desired particle size obtained in the pulverizing step, and subsequently. It means fine particles and coarse particles other than the components that are generated in the classification step and have a desired particle size. In the mixing step or the melt-kneading step of such a by-product, it is preferable to mix the raw materials and preferably the by-product 1 at a weight ratio of the other raw materials 50 to the by-product 50 from the other raw materials 99.

The mixing step of mechanically mixing the toner components composed of the constituent materials may be performed under ordinary conditions using an ordinary mixer with rotating blades, and is not particularly limited.

After the above-mentioned mixing step is completed, the mixture is then charged into a kneader and melt-kneaded. As the melt kneader, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. For example, a KTK twin screw extruder manufactured by Kobe Steel, a TEM extruder manufactured by Toshiba Machine Co., a twin screw extruder manufactured by KCK, a PCM twin screw extruder manufactured by Ikegai Iron Works, Bus A co-kneader or the like is preferably used.

It is important that the melt-kneading is performed under appropriate conditions so as not to cause the breaking of the molecular chain of the binder resin. Specifically, the melt-kneading temperature should be determined with reference to the softening point of the binder resin. If the temperature is lower than the softening point, cutting is severe, and if the temperature is too high, dispersion does not proceed.

When the above-described melt-kneading process is completed, the kneaded material is then pulverized. In this pulverization step, it is preferable to first perform coarse pulverization and then finely pulverize. At this time, a method of crushing by colliding with a collision plate in a jet stream, crushing by colliding particles in a jet stream, or crushing with a narrow gap between a mechanically rotating rotor and a stator is preferably used. .

After the completion of the pulverizing step, the pulverized material is classified in a gas stream by centrifugal force or the like, thereby producing a developer having a predetermined particle size, for example, an average particle size of 5 to 20 μm. Further, when preparing the developer, the hydrophobic silica fine particles mentioned above are further added to the developer manufactured as described above in order to enhance the fluidity, preservability, developability and transferability of the developer. Inorganic fine particles such as powder are added and mixed. A general powder mixer is used for mixing the external additives, but it is preferable that the internal temperature can be adjusted by providing a jacket or the like. In order to change the history of the load applied to the external additive, the external additive may be added during or gradually. Of course, the rotation speed, rolling speed, time, temperature, etc. of the mixer may be changed. A strong load may be applied first, followed by a relatively weak load, or vice versa.

Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Loedige mixer, a Nauta mixer, and a Henschel mixer.

When the toner of the present invention is used for a two-component developer, the toner may be mixed with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is based on 100 parts by weight of the carrier. The amount of the toner is preferably 1 to 10 parts by weight. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, and magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. Further, as the coating material, amino resins, for example, urea-formaldehyde resin, melamine resin, benzoguanamine resin,
Urea resin, polyamide resin, epoxy resin and the like can be mentioned. Further, polyvinyl and polyvinylidene resins, for example, acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins such as polystyrene resins and styrene acrylic copolymer resins, polychlorinated resins Halogenated olefin resin such as vinyl, polyester resin such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin ,
Fluoroterpolymers such as copolymers of vinylidene fluoride and acrylic monomers, copolymers of vinylidene fluoride and vinyl fluoride, and terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers And the like can be used, but silicone resin is superior from the viewpoint of developer life.

If necessary, a conductive powder or the like may be contained in the coating resin. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide and the like can be used. These conductive powders preferably have an average particle size of 1 μm or less. When the average particle size is larger than 1 μm,
It becomes difficult to control the electric resistance.

[0068]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to only these examples. In the following examples, parts and percentages are by weight unless otherwise specified.

(Synthesis Example of Charging Control Resin) Synthesis Example 1 600 parts of 3,4-dichlorophenylmaleimide and 100 parts of perfluorooctanesulfonic acid were dissolved in dimethylformaldehyde (DMF) under boiling point using ditertiary butyl peroxide as an initiator. Copolymerized for hours. Next, 300 parts of n-butyl acrylate was added, and graft polymerization was carried out for 4 hours using ditertiary butyl peroxide as an initiator. Then, DMF was distilled off with a reduced pressure drier to obtain a number average molecular weight of 10,000 and an apparent viscosity of 10 ⁴ P (10 ^{4 4} g / c
m.s) to obtain a charge control resin A having a temperature of 95 ° C.

Synthesis Example 2 m-Nitrophenylmaleimide (600 parts) and 2-acrylamido-2-methylpropanesulfonic acid (100 parts) were copolymerized in dimethylformaldehyde (DMF) at a boiling point of 8 hours using ditertiary butyl peroxide as an initiator. . Then 2-ethylhexyl acrylate was added to 250
After graft polymerization for 4 hours using ditertiary butyl peroxide as an initiator, DMF was removed by a vacuum drier to give a number average molecular weight of 1500 and an apparent viscosity of 1
^{0 4 P (10 4 g /} cm · s) and becomes a temperature of 85 ° C. charging
Control resin B was obtained.

Synthesis Example 3 500 parts of 3,4-dichlorophenylmaleimide and 2-part
Acrylamide-2-methylpropanesulfonic acid 150
The part was copolymerized in dimethylformaldehyde (DMF) at a boiling point for 8 hours using ditertiary butyl peroxide as an initiator. Next, 350 parts of n-butyl acrylate was added, and graft polymerization was performed for 4 hours using ditertiary butyl peroxide as an initiator. Then, DMF was removed by a reduced-pressure drier, and the number average molecular weight was 98500 and the apparent viscosity was 1
A zone where the temperature at which 0 ⁴ P (10 ⁴ g / cm · s) becomes 110 ° C
Electric control resin C was obtained.

Synthesis Example 4 500 parts of 3,4-dichlorophenylmaleimide and 200 parts of perfluorooctanesulfonic acid were copolymerized in dimethylformaldehyde (DMF) at a boiling point of 8 hours using ditertiary butyl peroxide as an initiator. Next, 300 parts of n-butyl acrylate was added, and graft polymerization was performed for 4 hours using ditertiary butyl peroxide as an initiator. After that, DMF was removed by a reduced-pressure drier to obtain a number average molecular weight of 12,000 and an apparent viscosity of 10 ⁴ P (10 ⁴ P). ⁴ g / c
m.s), a charge control resin D having a temperature of 102 ° C. was obtained.

[0073]Synthesis Example 5 400 parts of 3,4-dichlorophenylmaleimide and 2-
Acrylamide-2-methylpropanesulfonic acid 100
Part in dimethylformaldehyde (DMF) under boiling point
8:00 with tertiary butyl peroxide as initiator
After copolymerization, DMF was removed by a vacuum drier,
Average molecular weight 5000, apparent viscosity 10 ^FourP (10^Fourg /
cm · s) is 101 ° CCharge control resin EGet
Was.

Synthesis Example 6 400 parts of 3,4-dichlorophenylmaleimide and
Acrylamide-2-methylpropanesulfonic acid 200
The part was copolymerized in dimethylformaldehyde (DMF) at a boiling point for 8 hours using ditertiary butyl peroxide as an initiator. Next, after adding and dissolving 750 parts of n-butyl acrylate, DMF was removed by a reduced-pressure drier, and the number average molecular weight was 115,000 and the apparent viscosity was 10 ⁴ P (10 ⁴ P).
g / cm · s) to become the temperature is 110 ° C. of the charge control resin F
I got

Synthesis Example 7 450 parts of 3,4-dichlorophenylmaleimide and 150 parts of perfluorooctanesulfonic acid were copolymerized in dimethylformaldehyde (DMF) at a boiling point of 3 hours using ditertiary butyl peroxide as an initiator. Then, 400 parts of methyl acrylate was added, and graft polymerization was performed for 4 hours using ditertiary butyl peroxide as an initiator. After that, DMF was removed by a reduced-pressure drier to obtain a number average molecular weight of 950 and an apparent viscosity of 10 ⁴ P (10 ⁴ g). / Cm · s)
Become temperature to obtain a charge control resin G of 82 ° C..

(Synthesis example of polyester resin) Synthesis example 1 Stirrer, thermometer, nitrogen inlet, falling condenser,
In a four-necked separable flask with a cooling tube, 740 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2,
2) 300 g of 2,2-bis (4-hydroxyphenyl) propane, 466 g of dimethyl terephthalate, 80 g of isododecenyl succinic anhydride, and 114 g of tri-n-butyl 1,2,4-benzenetricarboxylate were added together with the esterification catalyst. Under a nitrogen atmosphere, the temperature was raised to normal temperature to 210 ° C. in the first half, and the reaction was performed while stirring at 210 ° C. under reduced pressure in the latter half. Acid value 2.3KOHmg / g, hydroxyl value 28.0KOHmg
/ G, a softening point of 106 ° C and a Tg of 62 ° C were obtained (hereinafter referred to as polyester resin A ).

Synthesis Example 2 Polyoxypropylene (2,2) -2,2-bis (4-
(Hydroxyphenyl) propane 71225 g, polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 165 g, terephthalic acid 500 g,
130 g of isododecenyl succinic anhydride and 170 g of triisopropyl 1,2,4-benzenetricarboxylate were added to the flask together with the esterification catalyst. These were reacted with the same apparatus and the same recipe as in Synthesis Example 1 to obtain an acid value of 0.5.
A polyester resin having a KOH mg / g, a hydroxyl value of 25.0 KOH mg / g, a softening point of 109 ° C. and a Tg of 63 ° C. was obtained (hereinafter referred to as polyester resin B ).

Synthesis Example 3 Polyoxypropylene (2,2) -2,2-bis (4-
650 g of hydroxyphenyl) propane, 650 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 515 g of isophthalic acid, 70 g of isooctenylsuccinic acid, and 80 g of 1,2,4-benzenetricarboxylic acid The catalyst was added to the flask along with the catalyst. These were reacted with the same apparatus and the same recipe as in Synthesis Example 1 to obtain an acid value of 19.5 KOH mg / g and a hydroxyl value of 3
A polyester resin having 5.0 KOH mg / g, a softening point of 110 ° C, and a Tg of 60 ° C was obtained (hereinafter, referred to as polyester resin C ).

Synthesis Example 4 Polyoxypropylene (2,2) -2,2-bis (4-
714 g of hydroxyphenyl) propane, 663 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 648 g of isophthalic acid, 150 g of isooctenylsuccinic acid, and 100 g of 1,2,4-benzenetricarboxylic acid as an ester The catalyst was added to the flask along with the catalyst. These were reacted with the same apparatus and the same prescription as in Synthesis Example 1 to obtain an acid value of 21.0 KOH mg / g, a hydroxyl value of 24.0 KOH mg / g, a softening point of 128 ° C., and a Tg of 65.
° C (hereinafter referred to as polyester resin D)
).

(Synthesis Example of Polyol Resin) Synthesis Example 1 In a separable flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a condenser, 378.4 g of a low-molecular bisphenol A type epoxy resin (number average molecular weight: about 360) was added. High molecular weight bisphenol A type epoxy resin (number average molecular weight: about 270
0) 86.0 g, glycidylated bisphenol A-type propylene oxide adduct (n + m in the above general formula (1): about 2.1) 191.0 g, bisphenol F
274.5 g, 70.1 g of p-cumylphenol, and 200 g of xylene were added. 70-100 ° C under nitrogen atmosphere
The temperature was raised to 160 ° C., and xylene was distilled off under reduced pressure.
Polymerization is carried out at a reaction temperature of 0 ° C. for 6 to 9 hours to obtain an acid value of 0.0K.
A polyol resin having an OH mg / g, a hydroxyl value of 70.0 KOH mg / g, a softening point of 109 ° C. and a Tg of 58 ° C. was obtained (hereinafter, referred to as a polyol resin).
Polyol resin A ).

Synthesis Example 2 Using the apparatus of Synthesis Example 1, 205.3 g of a low molecular weight bisphenol A type epoxy resin (number average molecular weight: about 360),
54.0 g of a high molecular bisphenol A type epoxy resin (number average molecular weight: about 3000), 432.0 g of a glycidylated product of a bisphenol A type propylene oxide adduct (n + m in the above general formula (1): about 2.2), bisphenol F282 0.7 g, p-cumylphenol 2
6.0 g and 200 g of xylene were added. The temperature was raised to 70 to 100 ° C. in a nitrogen atmosphere, and lithium chloride was added to 0.183.
g, further heated to 160 ° C., distilled off xylene under reduced pressure, and polymerized at a reaction temperature of 180 ° C. for 6 to 9 hours.
Acid value 0.0 KOHmg / g, hydroxyl value 58.0 KOHm
A polyol resin having a g / g, a softening point of 109 ° C. and a Tg of 58 ° C. was obtained (hereinafter referred to as polyol resin B ).

(Production Example of Toner Colored Particles) (Toner N
o. T1) As specifically described below, four-color electrophotographic toners were manufactured, and the obtained toners were evaluated. Preparation Example 1 of Colored Particles for Toner 1 1200 parts water 200 parts phthalocyanine green water-containing cake (solid content 30%) 540 parts carbon black (manufactured by Printex 35 Dexa) 540 parts (DBP oil absorption = 42 ml / 100 mg, pH = 9.5) Stir well. Here, 1200 parts of polyester resin A was added, kneaded at 150 ° C. for 30 minutes, 1000 parts of xylene was added, kneading was further performed for 1 hour, water and xylene were removed, roll-cooled, and pulverized with a pulperizer.
A masterbatch pigment was obtained.

100 parts of polyester resin A 5 parts of master batch 5 parts of charge control resin A 5 parts The above materials were mixed by a mixer, then melt-kneaded by a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, a jet plate mill (I-2 type mill; manufactured by Nippon Pneumatic Industries Co., Ltd.) using a jet mill and a wind classifier (DS classifier;
Nippon Pneumatic Industry Co., Ltd.), and a diameter average diameter of 5.2 μm and a volume average diameter of 6.5 μm (Dv / Dn = 1.
3) Black colored particles were obtained. At that time, the pulverization amount per unit time was 2.3 kg / H.

Preparation Example of Colored Particles for Toner 2 600 parts of water 1200 parts of a pigment-containing 17 water-containing cake (50% solids) are thoroughly stirred with a flasher. To this, 1200 parts of polyester resin A was added, kneaded at 150 ° C. for 30 minutes, 1000 parts of xylene was added, kneading was continued for 1 hour, water and xylene were removed, rolled and cooled, pulverized with a pulperizer, and further passed twice with three rolls Thus, a master batch pigment was obtained.

100 parts of polyester resin A 5 parts of the above master batch 5 parts of charge control resin A 5 parts The above materials were mixed by a mixer, melt-kneaded by a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed in the same manner as in the production example of black colored particles, and the number average diameter was 5.
4 μm, volume average diameter 6.6 μm (Dv / Dn = 1.2)
Of yellow colored particles were obtained. At that time, the pulverization amount per unit time was 2.3 kg / H.

Preparation Example of Colored Particles for Toner 3 600 parts of water Pigment Red 57 water-containing cake (50% solids) 1200 parts The above is thoroughly stirred with a flasher. Here, 1200 parts of polyester resin A was added, kneaded at 150 ° C. for 30 minutes, 1000 parts of xylene was added, kneading was further performed for 1 hour, water and xylene were removed, roll-cooled, and pulverized with a pulperizer.
Further, the mixture was passed twice with a three-roll mill to obtain a master batch pigment.

100 parts of polyester resin A 5 parts of master batch 5 parts of charge control resin A 5 parts The above materials were mixed by a mixer, then melt-kneaded by a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed in the same manner as in the production example of the black colored particles, and the number average diameter was 5.2.
μm, volume average diameter 6.8 μm (Dv / Dn = 1.3) magenta colored particles were obtained. At that time, the pulverization amount per unit time was 2.3 kg / H.

Production Example 4 Colored Particles for Toner 4 600 parts of water Pigment Blue 15: 3 1200 parts of a water-containing cake (50% solids) is thoroughly stirred with a flasher. To this, 1200 parts of polyester resin A was added, kneaded at 150 ° C. for 30 minutes, 1000 parts of xylene was added, kneading was further performed for 1 hour, water and xylene were removed, roll-cooled, pulverized with a pulperizer, and further passed twice with a three-roll mill. Then, a master batch pigment was obtained.

100 parts of polyester resin A 3 parts of master batch 3 parts of charge control resin 5 parts The above materials were mixed by a mixer, melt-kneaded by a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed in the same manner as in the production example of black colored particles, and the number average diameter was 5.
9 μm, volume average diameter 6.9 μm (Dv / Dn = 1.2)
Of cyan colored particles were obtained. At that time, the pulverization amount per unit time was 2.3 kg / H. The four colored particles obtained as described above are the base toner, and the toner No. T1 was set.

(Production of Toner Colored Particles) (Toner N
o. T2 to T14) Except that the charge control resin, the amount thereof added, and the binder resin were changed to those shown in Table 2 below, the colored particles of each color as the base toner were prepared in the same manner as in Example 1. Manufactured, and T2 to T14. Table 2 also summarizes the properties of the thus-obtained colored particles for toner (T1 to T14) such as the particle size, transparency, and crushability.

(Preparation of External Additives) As external additives, Table 1-1 was used.
Silica (I) having the physical properties shown in Table 1-3,
(II) and titanium oxide (II) were prepared.

[0092]

[Table 1]

[0093]

[Table 2]

[0094]

[Table 3]

[Example 1]

(Evaluation of Mixing with External Additive and Toner Obtained) An external additive was added to each of 100 parts by weight of the four colored particles of T1 in the combinations and amounts shown in Table 3 described below, and the colored particles to which the external additive was added were mixed by a Henschel mixer. Then, opening 1
By passing through a 00 μm mesh to remove coarse particles and aggregates, an electrophotographic toner was obtained.

(Two-Component Developer) When the toner obtained as described above is used for image formation and the image is evaluated with a two-component developer, the toner was coated with a silicone resin at an average thickness of 0.3 μm. Using a ferrite carrier having an average particle diameter of 50 μm, 5 parts by weight of each color toner is uniformly mixed and charged using a turbuler mixer of a type in which a container is tumbled and stirred with respect to 100 parts by weight of a carrier to prepare a developer. did.

(Toner Evaluation Machine) The obtained toner is developed by a developing unit for four colors in which a non-magnetic one-component developer is sequentially developed for each color on one belt photoreceptor, and sequentially transferred to an intermediate transfer body. Full color laser printer that transfers colors all at once
Epsio 5000 (made by Ricoh Company, evaluation machine A),
A tandem-type full-color LED printer GL8300 (Fujitsu Ltd., evaluation machine B) having a non-magnetic one-component developing unit for four colors and a photoreceptor for four colors and sequentially transferring to a transfer paper or the like A full-color laser copying machine of the type that develops each color on one drum-shaped photoconductor by a four-color developing unit having a component-based developer, sequentially transfers it to an intermediate transfer body, and collectively transfers four colors of toner onto transfer paper or the like. Color 28
00 (manufactured by Ricoh, Evaluator C) and a full-color laser printer, Ipsio 5000 (Ricoh)
Was evaluated using a modified non-contact AC bias developing tester (evaluator D). The developing units of the evaluation machines A and B are equipped with a developing sleeve made of an elastic body and a non-magnetic one-component developing unit made of a stainless steel blade with a regulated thickness. In addition, all of the four types of evaluation machines are of the reversal development type in which the polarity of the electrostatic latent image on the photoconductor and the polarity of the non-magnetic one-component developer are the same.

(Evaluation Items) For each item, an image chart having a 5% image area was continuously printed up to 100,000 sheets, and then the obtained images and photosensitive members were evaluated as described below. The evaluation results are shown in Tables 4-1 to 4-3 described below.

1) Image Density After outputting a solid image, the image density was changed to X-Rite (X-Rit).
e). This was measured at five points for each color alone, and the average was determined for each color.

2) Background Stain The white paper image was stopped during development, the developer on the photoreceptor after development was transferred to a tape, and the difference from the image density of the untransferred tape was measured using a 938 spectrodensitometer (X-Rite). Measured by the company).

3) Thin Layer Formability The thin layer property of the toner on the developing sleeve was visually observed.が: uniform and good condition, 数: several white streaks are seen slightly, no streaks appearing in the image, ×: many white streaks occurred, image clearly appeared as image density unevenness In the worst case, especially, toner scattering occurred.

4) Image edge portion dust The printed image was observed with a 30-power loupe for the dust edge condition at the image edge portion. O is a sharp image with almost no dust, Δ is slightly observed but lacks sharpness, and X is not a sharply sharp and clear image, and terrible is found in the background stain.

5) Filming The occurrence of toner filming on the developing sleeve or the photosensitive member was observed.が indicates no filming, Δ indicates filming on streaks, and × indicates filming as a whole.

6) Measurement of Physical Properties 6-1) [Particle Size] The particle size of the toner was measured with a particle size analyzer “Coulter Counter TAII” manufactured by Coulter Electronics Co., Ltd., with an aperture diameter of 100 μm. The volume average particle size and the number average particle size were determined by the above particle size analyzer.

6-2) [Charge Amount] In the case of a two-component developer, 6 g of the developer is weighed, charged into a sealable metal cylinder, and blown to determine the charge amount. The toner concentration is adjusted to 4.5 to 5.5 wt%. In the case of a one-component toner, the toner was conveyed onto a developing roller (sleeve) and measured by a suction tribo measurement method under each environment. The high temperature and high humidity are 32 ° C. and 80 RH%, and the low temperature and low humidity are 10 ° C. and 30 RH%.

7) Transparency A sample was prepared using an OHP sheet at 160 ° C. at a fixing speed of 90 mm / s. This was measured for transparency using a haze meter (Suga Test Machine Co., Ltd.).ヘ for less than 15% haze, Δ for less than 30%, 30%
The above was evaluated as x.

8) Pulverizability (Productivity) As described above, the kneaded material was crushed by a jet mill using an impingement plate type pulverizer (type I-2 mill; manufactured by Nippon Pneumatic Industries Co., Ltd.) and the air was classified by a swirling flow ( DS classifier; manufactured by Nippon Pneumatic Industries Co., Ltd.), and the volume average diameter is 6.5 μm.
(Dv / Dn = 1.5 or less) Adjusted to obtain colored particles, and the pulverization amount per unit time (Kg / H) at that time
Was measured. 2.0 (Kg / H) or more
g / H).

[Examples 2] to [Example 10] and [Comparative Examples 1] to [Comparative Example 11] Examples 2 to 1 were prepared by combining external additives as shown in Table 3.
0 and Comparative Examples 1 to 11 were produced.
With respect to these electrophotographic toners, the same evaluation as in Example 1 was performed, and the results are shown in Tables 4-1 to 4-3 below. The point of the present invention is that the electrophotographic toner of the present invention has a configuration in which three types (two types of silica and titanium oxide) of external additives are added (see the above-mentioned embodiment (1) of the present invention). From this point of view, Comparative Examples 7 to 9 are included in the aspect (1) of the present invention in terms of structure, however, from the viewpoint of the optimal addition amount of the external additive in the aspect (7) of the present invention. The point was deviated from the comparative example. Further, Comparative Examples 10 to 11 are also included in the aspect (1) of the present invention, but Comparative Example 10 is an aspect (4) of the present invention.
Comparative Example 11 is a comparative example in that the number average molecular weight of the charge control agent is out of the range specified in the above, and the amount of the antistatic control agent added in the embodiment (5) of the present invention is out of the range.

[0110]

[Table 4]

[0111]

[Table 5]

[0112]

[Table 6]

[0113]

[Table 7]

[0114]

[Table 8]

[0115]

According to the present invention, in both the two-component and one-component color developing systems, after long-term continuous printing, there is no filming on the photosensitive member, the developer layer thickness regulating member or the developing sleeve. The thin layer on the developing sleeve is uniform and good, stabilizes the charging and conveyance of the toner, there is no dust at the edge of the image, and the electrophotographic toner that can maintain the same image density and high quality output image as the initial image. can get. In addition, since there is little decrease in charge during continuous use, there are no problems such as fluctuations in image density, low developability, background fouling, and scattering of toner in a developing device, and an image having good color developability and color reproducibility can be obtained. Because of this long-term durability, the life of the developing unit and photoreceptor unit can be prolonged, and the amount of recyclables and waste generated after use is smaller than before. Can be reduced. Furthermore, in the production process of kneading, pulverizing and classifying the toner, an electrophotographic toner having good productivity can be obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/01 G03G 9/08 321 15/08 504 331 9/10 352 (72) Inventor Osamu Uchinokura Tokyo 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Shinichiro Yagi 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Company Limited 2H005 AA01 AA06 BA06 CA04 CA08 CA12 CA20 CB07 CB13 DA02 DA05 EA03 EA05 EA06 EA07 EA10 2H030 AD01 AD04 BB38 2H077 AD06 AD13 AD14 AD17 EA01 EA11 EA15 EA16 GA13

Claims (11)

[Claims] 1. An electrophotographic toner comprising at least a binder resin and a colorant, wherein the binder resin is a polyester and / or a polyol; and the electrophotographic toner further contains a charge control agent; The agent is a resin charge control agent having at least a sulfonic acid group-containing monomer, an aromatic monomer having an electron-withdrawing group, and an acrylate and / or methacrylate monomer as a monomer; The repeating unit of the monomer is 1 to 30% by weight based on the weight of the resin charge controlling agent, the repeating unit of the aromatic monomer having the electron withdrawing group is 1 to 80% by weight based on the weight of the resin charging controlling agent, And a proportion of the repeating unit of the methacrylic acid ester monomer of 10 to 80% by weight based on the weight of the resin charge control agent Including, electrophotographic toner, wherein the toner for the electrophotography further contain an external additive, following the external additive (I), containing (II) and (III). (I) Hydrophobized silica having a primary particle size of 0.01 to 0.03 μm. (II) Hydrophobized titanium oxide having a primary particle size of 0.01 to 0.03 μm and a specific surface area of 60 to 140 m ² / g. (III) Specific surface area 20-50 m ² / g, bulk density 100
~ 250 g / l of hydrophobized silica. 2. The method according to claim 1, wherein the aromatic monomer having an electron-withdrawing group is a substituted phenylmaleimide or a substituted phenylitaconimide substituted with a chlorine atom or a nitro group. Electrophotographic toner. 3. The temperature at which the apparent viscosity of the resin charge control agent measured by a flow tester reaches 10 ⁴ P (10 ⁴ g / cm · s) is 85 to 110 ° C.
Or the electrophotographic toner according to 2. 4. The resin charge control agent having a number average molecular weight of 1
2. The method according to claim 1, wherein the number is from 000 to 100,000.
4. The electrophotographic toner according to any one of claims 1 to 3. 5. The electrophotographic toner according to claim 1, wherein the resin charge control agent is contained in an amount of 0.1 to 20% by weight based on the toner particles. 6. The binder resin having an acid value of 20 KOHmg /
The electrophotographic toner according to any one of claims 1 to 5, wherein the value is not more than g. 7. The external additives (I) to (III) each contain 0.1 to 1.
5 parts by weight, 0.1 to 1.5 parts by weight of (II) and 0.3 to 2.0 parts by weight of (III).
7. The electrophotographic toner according to any one of 6. 8. A two-component developer using the electrophotographic toner according to claim 1, wherein the carrier is a silicon-coated carrier. 9. A latent image forming step of forming a latent image on a latent image holding member, a developing step of developing the latent image using a developer on a developer carrying member, and a step of transferring the developed toner image onto a transfer member. 8. An image forming method, comprising: a transfer step of transferring a toner image onto a toner image;
An image forming method, which is a one-component developer using the electrophotographic toner according to any one of the above. 10. The image forming apparatus according to claim 9, wherein in the developing step, a thin layer of the developer is formed on the developer carrying member, and the developing is performed in contact with or not in contact with the latent image holding member. Method. 11. A multi-color developing device provided with a developing roll and a plurality of multi-color developing devices provided with a layer thickness regulating member for uniformly controlling a layer thickness of a developer supplied on the developing roll. The electrostatic latent image divided into a plurality of electrostatic latent images is developed on a plurality of electrostatic image carriers corresponding to each color by a developer corresponding to each color, and is transferred to a surface of the electrostatic image carrier via a transfer material by a transfer unit. An electrophotographic developing method used in an electrophotographic recording apparatus for abutting the toner image on the transfer material to sequentially and electrostatically transfer the toner image onto the transfer material, wherein the electrophotographic toner according to any one of claims 1 to 7 is used. An image forming method comprising using a component developer.