JPH1020560A - Electrophotographic toner, its production and image forming method using the toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the electrostatic charge and conveyance of a toner over a long period of time and to provide an electrophotographic toner not causing fog and unevenness in density and ensuring stable image density. SOLUTION: This electrophotographic toner contains a bonding resin, a colorant and an electrostatic charge controlling agent contg. a compd. represented by the formula (where M is a metallic element selected from among Zn, Fe, Ni and Co and each of R<1> and R<2> is H or 1-6C alkyl). The ratio of the average dispersion diameter (μm) of the electrostatic charge controlling agent to the vol. verage particle diameter (μm) of the toner particles is 0.1-0.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic toner and an image forming method using the same.

[0002]

2. Description of the Related Art At present, as a dry developing method in various electrostatic copying systems put into practical use, a two-component developing system using a carrier such as toner and iron powder and a one-component toner developing system using no carrier are known. Have been. In the two-component developing method, the toner particles adhere to the surface of the carrier, thereby deteriorating the developer. Further, since only the toner is consumed and the concentration ratio of the toner in the developer decreases, the mixing of the toner and the carrier is prevented. Since a density controller or the like for keeping the ratio constant is required, there is a disadvantage that the size of the developing device is increased. On the other hand, the one-component developing method does not have the above-mentioned problem because it does not use a carrier, has advantages such as miniaturization and weight reduction of the apparatus, and is becoming the mainstream of the developing method.

[0003] The one-component developing method is classified into a magnetic one-component developing method using a magnetic toner and a non-magnetic one-component developing method using a non-magnetic toner. The magnetic one-component developing method is to hold and develop a magnetic toner using a developer carrier provided with a magnetic field generating means such as a magnet inside, and has recently been used in many small printers. In this method, the magnetic toner used contains a black magnetic substance such as magnetite inside,
It is difficult to use for colorization.

On the other hand, the non-magnetic one-component developing system is suitable for colorization because the toner does not contain a magnetic substance, and furthermore, since a magnet is not used for a developer carrier, the weight and cost can be reduced. In recent years, it has begun to be used in small full-color printers and the like. However, for example, in the two-component developing method, stable charge called a carrier,
There is a conveying member, and in the magnetic one-component developing method, there is a stable conveying and layer forming means of the magnetic force of the magnet roll, whereas in the non-magnetic one-component developing method, there is no such stable charging and conveying means, Therefore, it is necessary to hold the toner on the developer carrier mainly by electrostatic force, so that the toner is required to have a higher charging property and stable charging characteristics.

Conventionally, to stabilize the charge of the toner, a charge control agent has been added to the inside of the toner. Typical examples of the negative charge control agent include metal-containing monoazo complexes such as chromium-containing azo dyes, and metal-containing salicylic acid compounds such as chromium, iron, and zinc. Among these charge control agents, metal-containing azo dyes can obtain a high charge amount relatively quickly, but have a poor charge retention property, so that they can be used for a long time for non-magnetic one-component development. In addition, problems such as fog and dart due to a decrease in the charge amount are likely to occur.

Further, metal-containing salicylic acid compounds are more excellent in charge retention than metal-containing azo dyes. Among them, chromium-containing salicylic acid compounds have a rapid charge rise and high charge can be obtained. However, when used for non-magnetic one-component development, the charge distribution is wide and the charge exchangeability is inferior, so the toner deteriorates with long-term use, and fog and low image density due to an increase in reverse polarity toner are increased. Problems easily occur. Furthermore, in some kinds of salicylic acid metal compounds other than metal chromium, those having a sharper charge distribution than chromium-containing salicylic acid compounds have been confirmed, but these are not necessarily sufficient in charge retention, and in particular, In long-term use of 5000 sheets or more, there are problems such as generation of fog and low image density, and the problem still remains.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances in the prior art, and has been made to solve the problems. That is, an object of the present invention is to provide an electrophotographic toner capable of stabilizing the charging and conveyance of the toner for a long period of time and obtaining a stable image density without fog or density unevenness.

[0008]

The inventors of the present invention have made various studies to solve the above-mentioned problems, and as a result, have used a specific charge control agent for the toner, and have set the dispersed state of the charge control agent as a dispersion state. The inventors have found that the above object can be achieved by using a toner having a specific relationship between the volume average particle diameter of the toner particles and the average dispersion diameter of the charge control agent used, and have completed the present invention. .

That is, the electrophotographic toner of the present invention comprises:
It has a binder resin, a colorant and a charge control agent,
The charge control agent contains a compound represented by the following formula (1), and the toner particles have a volume average particle diameter of Dμ.
m, when the average dispersion diameter of the charge control agent is d μm,
The d / D value is in the range of 0.1 to 0.5.

[0010]

Embedded image (In the formula, M represents a metal element selected from zinc, iron, nickel, and cobalt, and R ¹ and R ² each represent hydrogen or an alkyl group having 1 to 6 carbon atoms.) The method for producing an electrophotographic toner has a melting and kneading step of melting and kneading a binder resin, a colorant and a charge control agent, and a pulverizing step of pulverizing the obtained kneaded material. A charge controlling agent containing the compound represented by the above formula (1) is previously charged with an average particle diameter of 50 to 500 μm.
m, and then melt-kneaded with other toner materials including a binder resin and a colorant, and the volume average particle diameter of the toner particles is D μm, and the average dispersion diameter of the charge control agent is d μm. At this time, a d / D value in the range of 0.1 to 0.5 is obtained.

Further, the image forming method of the present invention develops an electrostatic latent image on an electrostatic latent image holding member by using a developer layer on a developer carrying member. A toner having a charge control agent containing a binder resin, a colorant and a compound represented by the formula (1), wherein the volume average particle diameter of the toner particles is D μm, and the average dispersion diameter of the charge control agent is dμ
An electrophotographic toner having a d / D value in the range of 0.1 to 0.5, where m, is used.

[0012]

Embodiments of the present invention will be described below in detail. The toner for electrophotography of the present invention comprises a latent image forming step of forming a latent image on a latent image holding member, and a latent image on the latent image holding member using a developer thinly formed on a developer holding member. Is used in an image forming apparatus having a developing step of developing a toner image on the latent image holding member, a transfer step of transferring the toner image on the transfer member to the transfer member, and a fixing step of thermally fixing the toner image on the transfer member. It is used in a full-color developing device using four color toners of yellow, magenta, cyan and black.

In the latent image forming step, a conventionally known method can be applied, and an electrostatic latent image is formed on a latent image holding member such as a photosensitive layer or a dielectric layer by an electrophotographic method or an electrostatic recording method. As the photosensitive layer of the latent image holding member used in the present invention, a known layer such as an organic or amorphous silicon can be used.
Further, as the cylindrical substrate, a substrate obtained by a known manufacturing method such as extruding aluminum or an aluminum alloy and then performing surface processing can be used.

In the developing step, a toner carrier (developing roll)
The toner supplied by the toner supply roll is formed into a thin layer by an elastic blade or the like on the rotating cylindrical member, and is transported to a developing area (nip portion), and the latent image holding member holds the developing roll and the electrostatic latent image. Are arranged in contact with each other or at a constant gap in the developing section, and the electrostatic latent image is developed with toner while applying a bias between the developing roll and the latent image holding member.

As the toner carrier used in the present invention, an elastic sleeve such as silicone rubber, aluminum, SU
Sleeves from which metals and ceramics such as S stainless steel have been drawn out, and those which have been subjected to surface treatment such as oxidation or metal plating, polishing, blasting, or coating with resins to control the transportability and chargeability of toner. Is used. To form the toner layer with the developing roll,
This is performed by bringing an elastic blade into contact with the surface of the sleeve. As the material of the elastic blade, a rubber elastic body such as silicone rubber or urethane rubber is preferably used,
In order to control the charge amount of the toner, an organic substance or an inorganic substance may be added and dispersed in the elastic body.

As a method of developing the four-color toner, four developing machines are arranged around the photoreceptor, and for each toner,
A method in which each step of charging, exposure and development is repeated for 4 cycles, and a method for charging, exposing and developing four colors of toner in one cycle. A method of charging, exposing, and developing a four-color toner for a developing machine is used. As a method of superimposing the four color toners, a method of transferring the toner image formed on the photoconductor one by one onto a transfer drum around which a transfer paper is wound and superimposing the toner image, and a method of superimposing the toner image formed on the photoconductor. After transferring the color toner image on the transfer body and superimposing the color toner image on the transfer body, collectively transferring the image onto the transfer paper, or by superimposing the color toner image on the photoreceptor and then transferring the image onto the transfer paper collectively Used. As the transfer means, a known type such as a contact type in which a transfer roller is pressed against a latent image holding member and a non-contact type using a corotron can be used.

In the cleaning step, toner remaining on the latent image holding member without being transferred in the transfer step is removed by a cleaner. As a cleaning means used in the present invention, a known means such as blade cleaning or roller cleaning is used. There are things. For the blade cleaning, an elastic rubber such as silicone rubber or urethane rubber is used. In the fixing step, the toner image transferred to the transfer member is fixed by a fixing device. As a fixing unit, a heat fixing system using a heat roll is preferable. Further, roller fixing with oil applied to prevent gross formation and improve OHP image quality, and oil-less fixing with a release agent added to toner to reduce the size of the apparatus are performed.

In the electrophotographic toner of the present invention, as a charge control agent, a compound represented by the following formula (1):
It contains a metal-containing salicylic acid compound.

Embedded image (In the formula, M represents a metal element selected from zinc, iron, nickel, and cobalt, and R ¹ and R ² each represent hydrogen or an alkyl group having 1 to 6 carbon atoms.) In the metal-containing salicylic acid compound represented by the formula, M is most preferably zinc among the above metal elements. R ¹ and R ² are more preferably hydrogen or an alkyl group having 4 or less carbon atoms from the viewpoint of dispersibility and fixability in a binder resin. These charge control agents having an average primary particle diameter of 0.1 to 5 μm are used.
The compounding amount is in the range of 0.1 to 10% by weight of the toner particles, preferably in the range of 1 to 6% by weight, depending on the required charge amount. Roller compactor (manufactured by Turbo Kogyo Co., Ltd.) to adjust the dispersion diameter in the toner
May be used by granulating in the range of 50 to 500 μm.

As the colorant used in the toner of the present invention,
Carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I.
I. Pigment yellow 97, C.I. I. Pigment
Yellow 12, C.I. I. Pigment yellow 17,
C. I. Pigment blue 15: 1, C.I. I. And CI Pigment Blue 15: 3. These colorants may be directly dispersed in the binder resin using a kneader, but it is preferable to use a masterbatch method or a flushing coloring material in order to improve dispersion and color development in the resin. .

Further, as the binder resin used for the toner,
Styrenes such as styrene and chlorostyrene, ethylene,
Monoolefins such as propylene, butylene, and isobutylene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, dodecyl acrylate; Phenyl acrylate,
Esters of α-methylene aliphatic monocarboxylic acids such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether, vinyl methyl ketone, vinyl hexyl Ketones, vinyl ketones such as vinyl isopropenyl ketone, and the like, and homopolymers and copolymers thereof, and the like, and particularly typical binder resins include polystyrene,
Styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene, polyester, polyurethane, Examples thereof include an epoxy resin, a silicone resin, a polyamide, a modified rosin, and a paraffin wax. Among them, as a full-color toner, a polyester resin is preferable, and a toner having a softening point of 90 to 120 ° C. is particularly preferable. The softening point referred to here is a melt viscosity of 10 ⁴ Pa · s (10 ⁵ pois) measured with a flow tester (manufactured by Shimadzu Corporation, nozzle 1 × 1 mm, load 10 kg).
The temperature in e).

A release agent may be added to the toner used in the present invention for the purpose of preventing gloss and offset. The release agent is preferably a paraffin having 8 or more carbon atoms, polyolefin, or the like. Examples thereof include paraffin wax, paraffin latex, microcrystalline wax, and the like, and polypropylene, polyethylene, and the like. These may be used alone or in combination. The amount added is preferably in the range of 0.3 to 10% by weight.

Further, for the purpose of imparting appropriate fluidity and chargeability to the toner, fine particles of a fluidizing agent are externally used. Examples of the fluidizing agent fine particles include inorganic fine powders such as hydrophobic silica, titanium oxide and alumina, fine powders of organic compounds such as fatty acids or derivatives thereof and metal salts thereof, fluorine-based resins, acrylic resins and styrene-based resins. Resin fine powder and the like are used, and these are used alone or in combination. In particular, hydrophobic silica or titanium oxide having an average particle diameter of 7 to 100 nm is preferably used. 0.1 to 3 parts by weight based on 100 parts by weight of the toner,
Preferably, it is used in the range of 0.3 to 1.5 parts by weight.
If the external addition amount is less than 0.1 part by weight, the toner surface coverage is low, so that sufficient fluidity cannot be imparted to the toner. On the other hand, when the amount of external addition is more than 3 parts by weight, fine powder adheres to the photoreceptor and easily causes comet and filming.

The toner particles used in the present invention preferably have a volume average particle diameter in the range of 4 to 12 μm, more preferably 6 to 10 μm. Volume average particle size is 4μm
In the case below, the fluidity is remarkably reduced, so that the formation of the layer becomes poor, which tends to cause fogging and dirt. On the other hand, when the thickness is 12 μm or more, not only the resolution is lowered and high image quality cannot be obtained, but also the charge amount per unit weight of the developer is reduced, so that the layer formation maintenance is low and fog and dirt are easily generated.

In the present invention, when the charge control agent is dispersed in the toner particles, the volume average particle diameter of the toner is D μm, and the average dispersion diameter of the charge control agent in the toner is d μm.
, The value of d / D needs to be in the range of 0.1 to 0.5, and preferably in the range of 0.2 to 0.5. If the value of d / D is less than 0.1, the number of charge control agents exposed on the surface of the toner particles increases, but even if the charge speed of the toner increases due to the small exposed area, the saturation charge amount and Since the charge retention is reduced, problems such as fog and low image density due to long-term use are likely to occur. On the other hand, when the value of d / D is larger than 0.5, the amount of the released charge control agent increases, and image defects such as black spots on images, black spots due to filming, and black streaks due to filming occur. Easier to do.

The toner used in the present invention can be produced by any known method, but a kneading and pulverizing method is particularly preferable. That is, after pre-mixing the binder resin, the colorant, the charge control agent and the like, melt-knead with a kneader,
After cooling the obtained kneaded material, it is preferable to pulverize and classify the toner particles, and then add and mix the external additive fine particles to the toner particles obtained. As the kneader, a Banbury mixer, a pressure kneader, a continuous mixer, an extruder, etc. are used.In order to keep the dispersion diameter of the charge control agent in the toner within a specified range, the kneader rotation speed, the set temperature, The kneading time and the like are appropriately adjusted.

[0026]

The present invention will be described below in detail with reference to examples. Example 1 Binder resin: Polyester resin 83 parts by weight (Ethylene oxide adduct of terephthalic acid / bisphenol A) (Weight average molecular weight Mw: about 10,000, Tg: 67 ° C) Pigment: Copper phthalocyanine blue 30% by weight flushing 14 parts by weight Coloring agent (the flushing polymer is the above-mentioned polyester resin) Charge control agent: 3,5-ditertiary butyl zinc salicylate 3 parts by weight (average particle diameter: 20 μm, primary particle diameter: 1 μm) A BR type Banbury mixer ( Rotation speed 100 rpm, ram pressure 3 kg / cm by Kobe Steel Ltd.)
^2. Kneading was performed for 3 minutes. The obtained kneaded material was cooled, coarsely pulverized, finely pulverized with a jet mill, and further classified with an air classifier to obtain a volume average particle diameter D.
_{As a result} , toner particles 1 having a particle size of 9.0 μm were obtained. The average dispersion diameter d of the charge control agent in the toner particles 1 was 1.7 μm. The average dispersion diameter dμm of the charge control agent was measured by cutting the toner to a thickness of 50 nm, taking a 4500-fold cross-sectional photograph of the toner using a transmission electron microscope, and using the photograph by an image analysis device. The method of measuring the area and obtaining the average diameter from the diameter [Heywood diameter (equivalent circle diameter)] of the circle having the same area as the particle was adopted. 100 parts by weight of the obtained toner particles 1 were mixed with 0.5 part by weight of silica treated with silicone oil having an average particle diameter of 12 nm and 0.7 parts by weight of titanium oxide having an average particle diameter of 15 nm using a Henschel mixer. 1 was placed in the cyan toner developing machine of the image forming apparatus shown in FIG.
A total of 10,000 print tests were conducted in a high-temperature, high-humidity environment of 85% RH and a low-temperature, low-humidity environment of 10 ° C and 30% RH, and high-quality images without density unevenness and fog continued until the end. Was obtained.

Example 2 The same materials as in Example 1 were premixed with a Henschel mixer, and then kneaded with a 2NCM kneader (manufactured by Kobe Steel Ltd.) at a rotor speed of 500 rpm and a supply speed of 100 kg / h. The obtained kneaded material is cooled, coarsely pulverized, finely pulverized with a jet mill, and further classified with an air classifier to obtain toner particles 2 having a volume average particle diameter D ₅₀ of 8.0 μm. Obtained. The average dispersion diameter of the charge control agent in the toner particles 2 was measured in the same manner as in Example 1.
It was 4 μm. To 100 parts by weight of the obtained toner particles 2, 0.6 parts by weight of silicone oil-treated silica having an average particle size of 12 nm and 0.9 parts of titanium oxide having an average particle size of 15 nm were added.
Example 1 After mixing parts by weight with a Henschel mixer,
When the image quality was evaluated in the same manner as in the above, a high-quality image without density unevenness and fog was continuously obtained.

Example 3 A Henschel mixer was prepared using the same materials as in Example 1 except that the charge control agent used was granulated to an average particle diameter of 120 μm using a roller compactor (manufactured by Turbo Kogyo) in advance. After pre-mixing, the twin screw extruder kneader TE
M50 (manufactured by Toshiba Machine Co., Ltd.) was kneaded at a set temperature of 140 ° C., a screw rotation speed of 300 rpm, and a supply speed of 150 kg / h. The obtained kneaded material is cooled, coarsely pulverized, finely pulverized with a jet mill, and further classified with an air classifier to obtain toner particles 3 having a volume average particle diameter D ₅₀ of 7.5 μm. Obtained. The average dispersion diameter of the charge control agent in the toner particles 3 was measured in the same manner as in Example 1, and was 2.8.
μm. To 100 parts by weight of the obtained toner particles 3, 0.8 parts by weight of silica treated with silicone having an average particle diameter of 12 nm and titanium oxide 1.0 having an average particle diameter of 15 nm were added.
Example 1 After mixing parts by weight with a Henschel mixer,
When the image quality was evaluated in the same manner as in the above, a high-quality image without density unevenness and fog was continuously obtained.

Comparative Example 1 The kneading conditions of the Banbury mixer were changed to a rotational speed of 150 rpm.
m, the ram pressure was 5 kg / cm ² , and the kneading time was 5 minutes. Toner particles were produced in the same manner as in Example 1 to obtain toner particles 4 having a volume average particle diameter D ₅₀ of 9.2 μm. The average dispersion diameter of the charge control agent in the toner particles 4 is 0.5
μm. To 100 parts by weight of the obtained toner particles 4, 0.5 parts by weight of silica treated with silicone oil having an average particle diameter of 12 nm and 0.7 parts of titanium oxide having an average particle diameter of 15 nm were added.
Example 1 After mixing parts by weight with a Henschel mixer,
When the image quality was evaluated in the same manner as in the above, fog due to a decrease in charge occurred when the number of sheets exceeded 5,000.

Comparative Example 2 The kneading conditions of the 2NCM kneader were as follows.
Toner particles were prepared in the same manner as in Example 2 except that kneading was performed at a feed rate of 100 kg / h at rpm, and toner particles 5 having a volume average particle diameter D ₅₀ of 8.0 μm were obtained. The average dispersion diameter of the charge control agent in the toner particles 5 is 0.2 μm
Met. To 100 parts by weight of the obtained toner particles 5, 0.6 parts by weight of silica treated with silicone oil having an average particle diameter of 12 nm and 0.9 parts by weight of titanium oxide having an average particle diameter of 15 nm were mixed by a Henschel mixer. When the image quality was evaluated in the same manner as in Example 1, fog due to charge reduction occurred when the number of sheets exceeded 5,000.

Comparative Example 3 The same materials as in Example 1 were preliminarily mixed with a Henschel mixer, and then set in a twin-screw extruder and kneader TEM50 (manufactured by Toshiba Machine Co., Ltd.) at a set temperature of 140 ° C. and a screw rotation speed of 300 r.
pm at a feed rate of 150 kg / h. The obtained kneaded material is cooled, coarsely pulverized, finely pulverized with a jet mill, and further classified with an air classifier to obtain toner particles 6 having a volume average particle diameter D ₅₀ of 7.3 μm. Obtained. The average dispersion diameter of the charge control agent in the toner particles 6 was determined in Example 1.
The measured value was 0.3 μm. 100 parts by weight of the obtained toner particles 6 has an average particle diameter of 12 nm.
0.8 parts by weight of silicone oil-treated silica and 1.0 part by weight of titanium oxide having an average particle diameter of 15 nm were mixed with a Henschel mixer, and the image quality was evaluated in the same manner as in Example 1. , Fog due to charge reduction occurred.

Comparative Example 4 The same charge controlling agent was granulated to an average particle diameter of 1000 μm using a roller compactor (manufactured by Turbo Kogyo Co., Ltd.) using the same material as in Example 1 using a Henschel mixer. After pre-mixing, using a twin-screw extruder kneader TEM50 (manufactured by Toshiba Machine Co., Ltd.), set temperature 140
° C, screw rotation speed 300rpm, supply speed 150k
g / h. The obtained kneaded material was cooled, coarsely pulverized, finely pulverized with a jet mill, and further classified with an air classifier to have a volume average particle size D ₅₀ of 7.8 μm.
m of toner particles 7 were obtained. The average dispersion diameter of the charge control agent in the toner particles 7 was 4.2 μm as measured in the same manner as in Example 1. 10 of the obtained toner particles 7
0 parts by weight, 0.8 part by weight of silicone oil-treated silica having an average particle diameter of 12 nm, and 1.0 part by weight of titanium oxide having an average particle diameter of 15 nm were mixed with a Henschel mixer, and then mixed in the same manner as in Example 1. When the image quality was evaluated, the occurrence of density unevenness and fogging was small, but black streaks due to filming of the photoreceptor occurred around 3000 sheets or more.

(Image Forming Apparatus) FIG. 1 shows an image forming apparatus used for image formation for evaluating image quality and the like in the present invention. Around the photosensitive drum 1, four toners of yellow, magenta, cyan, and black, respectively, are provided.
The three developing machines 3 are arranged such that the developing roll 4 is spaced from the photosensitive drum 1 by a constant distance. Also, the photosensitive drum 1
Is charged with a corotron charger 2 and then exposed to laser light to form an electrostatic latent image. An AC voltage and a DC voltage are applied to the developing roll 4 and the developer supply roll 5 to form the electrostatic latent image. And charge, exposure, and development of the four-color toner
Performed in cycles. The formation of the toner layer on the developing roll 4 was performed by bringing the rubber layer forming blade 6 into contact with the developing roll 4 at a constant linear pressure. The peripheral speed of the photosensitive drum 1 is 80 mm / s, and the peripheral speed of the developing roll 4 is 1 mm.
A transfer roller was used to transfer the toner at 20 mm / s, and a four-color toner image was superimposed on the photoreceptor and then transferred collectively. For cleaning, a blade-type cleaner was used.

Table 1 shows the results obtained in Examples 1 to 3 and Comparative Examples 1 to 4.

[Table 1] In “density unevenness”, “○” means that the density difference is less than 0.1
Δ indicates a density difference of 0.1 to less than 0.3, and X indicates a density difference of 0.
Indicates three or more. In “fog” and “black streaks”, ○ means that there is no occurrence and is good, and X means that there is occurrence and there is a problem. In “Comprehensive evaluation”, ○ means good, and × means a problem.

[0035]

The toner for electrophotography according to the present invention stabilizes the charging and conveyance of the toner for a long period of time, and provides a stable image density without fog and density unevenness. Even if the image quality deteriorates, the toner charge distribution is sharp and the charge amount is small, so that even if image formation is performed for a long period of time, problems such as fluctuations in image density, low developability, and fog occur. It is possible to obtain an image of excellent image quality without performing.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus used for image formation for evaluating image quality and the like in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoreceptor drum, 2 ... Corotron charger, 3 ... Developing machine, 4 ... Developing roll, 5 ... Developer supply roll, 6 ... Layer forming blade.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kotaro Yoshihara Fuji Xerox Co., Ltd., 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture (72) Inventor Masahiro Uchida 1600 Taketake Matsu, Minami Ashigara City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Etsuo Tominaga 1600 Takematsu, Minamiashigara, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd.

Claims (7)

[Claims] 1. An electrophotographic toner having a binder resin, a colorant and a charge control agent, wherein the charge control agent contains a compound represented by the following formula (1), and the volume of the toner particles is When the average particle diameter is D μm and the average dispersion diameter of the charge control agent is d μm, the d / D value is 0.1 to 0.1.
5. A toner for electrophotography, which is in the range of 5. Embedded image (In the formula, M represents a metal element selected from zinc, iron, nickel, and cobalt, and R ¹ and R ² each represent hydrogen or an alkyl group having 1 to 6 carbon atoms.) 2. The electrophotographic toner according to claim 1, wherein a binder resin in which a pigment is dispersed in advance is used. 3. A method for producing an electrophotographic toner, comprising: a melt kneading step of melt kneading a binder resin, a colorant and a charge controlling agent; and a pulverizing step of pulverizing the obtained kneaded material.
In the melt-kneading step, a charge control agent containing a compound represented by the following formula (1) is granulated in advance to an average particle diameter of 50 to 500 μm, and then melt-kneaded with another toner material containing a binder resin and a colorant. The volume average particle diameter of the toner particles is D μm, and the average dispersion diameter of the charge control agent is d μm.
Wherein a d / D value in the range of 0.1 to 0.5 is obtained. Embedded image (In the formula, M represents a metal element selected from zinc, iron, nickel, and cobalt, and R ¹ and R ² each represent hydrogen or an alkyl group having 1 to 6 carbon atoms.) 4. A compound represented by the formula (1):
The method for producing an electrophotographic toner according to claim 3, wherein the toner is contained in an amount of 10% by weight. 5. The method for producing an electrophotographic toner according to claim 3, wherein the compound represented by the formula (1) has an average dispersion diameter of 0.1 to 5 μm. 6. A step of melting and kneading a toner material having a binder resin, a colorant and a charge control agent in which a pigment is dispersed in advance, wherein the volume average particle diameter of the toner particles is D μm, and the average dispersion of the charge control agent is When the diameter is d μm, the d / D value is 0.1.
A method for producing an electrophotographic toner, which is in the range of 1 to 0.5. 7. An image forming method for developing an electrostatic latent image on an electrostatic latent image holding member by using a developer layer on a developer carrying member, wherein the developer comprises a binder resin, a colorant, and a toner. A toner having a charge controlling agent containing the compound represented by (1), and having a volume average particle diameter of Dμ
m, when the average dispersion diameter of the charge control agent is d μm, d /
An image forming method using an electrophotographic toner having a D value in the range of 0.1 to 0.5.