JP2787896B2 - Electrophotographic toner composition, electrophotographic developer and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner composition used for an electrostatic latent image in electrophotography and electrostatic recording, an electrophotographic developer and an image forming method using the same. About.

[0002]

2. Description of the Related Art Conventionally, electrophotographic developers used for visualizing an electrostatic latent image formed on an electrophotographic photosensitive layer include polystyrene, styrene-butadiene copolymer, polyester and the like. Pigments or dyes such as carbon black and phthalocyanine blue are used as colorants for the resins, melt-kneaded, and then a one-component developer consisting of the toner obtained by pulverization, or as a carrier, the average particle size of the toner particles. A two-component developer in which toner is mixed with glass beads, particles of iron, nickel, ferrite, or the like having a diameter almost the same or up to 500 μm, or a particle obtained by coating these with various resins is generally used.

[0003] However, with these developers alone,
Properties such as storage stability (blocking resistance), transportability, developability, transferability, and chargeability are not sufficient. Therefore, additives are often externally added to the toner for the purpose of improving these characteristics. And as an additive,
For example, hydrophobic fine powder represented by hydrophobic silica and the like (see JP-A-52-30437), silica fine particles mixed with aluminum oxide and titanium oxide fine particles (see JP-A-60-238847). ), Hydrophobicized titanium oxide fine particles (see JP-A-59-52255) or alumina-coated titania fine particles (JP-A-57-52255).
It is known to use such a method. As for titanium oxide, a titanium oxide having an anatase type crystal structure has been proposed (JP-A-60-1).
No. 12052).

On the other hand, in recent years, high-definition,
There is an increasing demand for higher image quality, and in the art, attempts have been made to achieve higher image quality by reducing the particle size of the toner.However, when the particle size is reduced, the charge amount per unit weight increases. And the image density is lowered and the durability is deteriorated. One of the causes is a decrease in the amount of developed toner with respect to the latent image on the photoconductor. This can be done by considering the amount of toner that can fill the potential well. However, as described above, when the toner particle diameter is small, the charge amount per unit weight tends to be large. The amount tends to decrease. Another is the efficiency of transferring the toner image of the photoreceptor to paper or the like (hereinafter referred to as transferability).
It is a decline. This generally involves electrically transferring the toner from the photoreceptor to paper or the like.However, if the particle size of the toner is reduced, the efficiency decreases due to the relatively large non-electrostatic adhesion. It is because. In addition, since the gravity per unit is inversely proportional to the cube of the particle diameter, it is easily expected that the fluidity of the toner is greatly deteriorated. Therefore, in the case of a small particle diameter toner, it is important that the developer is constituted so that the problem of charging and the problem of fluidity are compatible, but hydrophobic silica which is a commonly used additive is used. It is difficult to satisfy these requirements depending on the external additive. This is due to the fact that the silica fine particles are themselves strongly negatively charged. For this reason, the toner to which silica is added has a large variation in charge amount in a high-temperature, high-humidity or low-temperature, low-humidity environment. For example, in a high-temperature and high-humidity environment, there is a tendency for background toner stains and in-machine contamination to occur, and in a low-temperature and low-humidity environment, the image density tends to decrease.

[0005] Hydrophobic fine powder represented by hydrophobic silica or the like (see Japanese Patent Application Laid-Open No. 52-30437), or silica fine particles mixed with aluminum oxide or titanium oxide fine particles (Japanese Patent Application Laid-Open No. 60-238847). ) Is insufficient in terms of charging stability because of the above. For example, by externally adding titanium oxide fine powder which has been subjected to a hydrophobic treatment with an alkyl trialkoxysilane, the occurrence of comet and filming is suppressed (Japanese Patent Publication No. 3-393).
JP-A-07-52255), and those using hydrophobicized titanium oxide (JP-A-59-52255).
Japanese Patent Application Laid-Open No. 6-208241) and those using alumina-coated fine particles of titania (see Japanese Patent Application Laid-Open No. 57-79961) have been proposed. In these cases, both transferability and fluidity are compatible. Have difficulty.

[0006] Under the circumstances described above, various studies have been made particularly for making full use of small particle diameter toner.
JP-A-4-348354 discloses that the average particle size is 8 μm.
It is disclosed that the following toners satisfy the chargeability and the transferability by using a relatively small amount of amorphous titania and a relatively large amount of silica in combination. However, in practice, the toner having an average particle diameter of 6 μm or less has a relatively large variation in chargeability and is insufficient. JP-A-4-
No. 337738 discloses that a toner having a particle size of 9 μm or less has
It is disclosed that inorganic or organic spherical particles of 80 nm are added. In this case, although the effect on transferability is observed, the chargeability is insufficient. JP-A-5-1195
No. 17 and JP-A-5-188633,
It is disclosed that a silicone-treated titania is used for a toner of 10 μm, and although the effect of controlling the charging property is seen to some extent, it is impossible to achieve both fluidity and transferability. In addition, Japanese Patent Application Laid-Open No. 6-75430 discloses 3-7.
It is described that a surface-treated anatase-type titania is added to a μm toner, but similarly, both fluidity and transferability cannot be achieved.

[0007] Japanese Patent Application Laid-Open No. 4-204749 discloses 10
It is described that the addition of titania or alumina having peaks at -20 nm and 30-60 nm to the toner prevents embedding of the additive particles on the small diameter side. It is necessary to use a control agent, and it cannot be said that the charge is sufficient. Further, Japanese Patent Application Laid-Open No. 6-95425 discloses that
It is disclosed that silica having different particle diameters of 20 nm or less and 30 to 50 nm is used for the following toners to secure fluidity and prevent spent of the toner, but it is satisfactory in terms of environmental stability of chargeability. Can not.

On the other hand, polyester resins have been used as binder resins for toners in order to obtain low-temperature fixability, high planar smoothness, and high transparency for color images. In this case, for example, when silica fine particles are contained as an additive (for example, Japanese Patent Application Laid-Open No. 62-174772), the environment dependency is increased, and the toner is scattered at low humidity at high humidity, and toner scattering occurs. In such a case, a problem arises in that the image density becomes high and the image density cannot be obtained. Further, there is a problem that the charge exchange property is poor and the toner is scattered when the toner is supplied. In order to solve this problem, it has been proposed to use titanium oxide fine powder as an additive (for example, Japanese Patent Publication No. 3-39307, Japanese Patent Application Laid-Open No. 4040467). This causes a problem that it is difficult to obtain proper charging.

[0009]

As described above, an object of the present invention is to obtain a high-quality image by reducing the particle size of the toner, and to provide a low-temperature fixing property by using a polyester resin as a binder resin. Conventional toners have the above-mentioned various problems, and there is a need for a toner that can solve these problems and that can be used in a well-balanced manner. Accordingly, an object of the present invention is to improve powder properties, transferability and cleaning properties, prevent comet and filming, improve the environment dependency of charging, and prevent toner scattering by improving charge exchangeability and charging properties. An object of the present invention is to provide a well-balanced electrophotographic toner composition and electrophotographic developer, and an image forming method using the same.

[0010]

Means for Solving the Problems The present inventors have conducted various studies and studies to improve the above-mentioned disadvantages in the prior art, and as a result, as an external additive to a toner having an average particle diameter of 3 to 6 μm. It has been found that the above requirements can be satisfied by using titanium oxide having primary particles having an average particle diameter of 5 to 25 nm and titanium oxide having an average particle diameter of 25 to 80 nm, thereby achieving the present invention.

The electrophotographic toner composition of the present invention comprises toner particles containing a colorant and a binder resin, and an additive, wherein the additive is surface-treated titanium oxide fine particles, Small-sized fine particles having an average particle diameter of 5 nm or more and less than 25 nm and an average particle diameter of 25 nm or more and 80 n
m or less, and the weight ratio of the small-diameter fine particles to the large-diameter fine particles is in the range of 1: 2 to 3: 1. 0.6% by weight
As described above, the content is 4.0% by weight or less, and titanium oxide is produced by a wet method, and the amount of a water-soluble component is 0.2% by weight or less. An electrophotographic developer according to the present invention is characterized by comprising the above-described electrophotographic toner composition and a carrier coated with an acrylic resin. The image forming method of the present invention includes a step of forming an electrostatic latent image on a latent image carrier, and a step of developing the formed electrostatic latent image. It is characterized in that a developer layer to be contained is formed on a developer carrier and development is performed.

Hereinafter, the present invention will be described in detail. In the present invention, the toner particles are composed of at least a colorant and a binder resin. As the colorant constituting the toner particles in the present invention, carbon black, nigrosine, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment Red 4
8: 1, C.I. I. Pigment Red 122, C.I. I.
Pigment Red 57: 1, C.I. I. Pigment Red 81: 3, C.I. I. Pigment Yellow 97,
C. I. Pigment Yellow 12, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 18
5, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3 and the like can be exemplified as typical examples. In the present invention, the content of the colorant in the toner particles is preferably in the range of 2% by weight to 10% by weight. When the content of the colorant is less than 2% by weight, the coloring power is weakened, and when the content is more than 10% by weight, the chargeability of the color toner is deteriorated.

The binder resin used in the present invention includes styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate. Vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate,
Α-methylene aliphatic monocarboxylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl methyl ether,
Homopolymers and copolymers such as vinyl ethers such as vinyl ethyl ether and vinyl butyl ether, and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone can be exemplified. Particularly typical binder resins include polystyrene resin, polyester resin, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer,
Styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer,
Examples include polyethylene resin and polypropylene resin. Further, polyurethane resins, epoxy resins, silicone resins, polyamide resins, modified rosins, paraffins, waxes and the like can be mentioned.

Among these resins, polyester resins are particularly preferred because they have a good balance of low-temperature fixability and transparency, and can provide high transparency required for color toners. The polyester resin can be synthesized from the following polyhydric alcohol and polyvalent carboxylic component.

The polyhydric alcohol component includes ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 2,3
-Butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentylene glycol, 1,4-
And dihydric alcohols such as bisphenol A alkylene oxide adducts such as cyclohexane dimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropylene bisphenol A. be able to. Further, a trihydric or higher polyhydric alcohol can be used to make the polymer non-linear so as not to generate a tetrahydrofuran insoluble component. Glycerin, sorbitol, 1,3
2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methylpropanetriol, 2-methyl-1,2 , 4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like.

The polycarboxylic acid component includes, for example, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, terephthalic acid, isophthalic acid, cyclohexanedicarboxylic acid, malonic acid, succinic acid Examples include dibasic carboxylic acids such as acids, adipic acid, sebacic acid, glutaric acid, and alkyl succinic acids (eg, n-octyl succinic acid, n-dodecenyl succinic acid), and acid anhydrides and alkyl esters thereof. In addition to these carboxylic acids, tribasic or higher polybasic carboxylic acids can be used to make the polymer non-linear to the extent that tetrahydrofuran insolubles are not generated. For example, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid,
1,2,4-cyclohexanetricarboxylic acid, 1,2,2
4-naphthalenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-carboxy Methylpropane, tetra (carboxymethyl) methane, 1,2,7,
8-octanetetracarboxylic acid, trimellitic acid, pyromellitic acid and lower alkyl esters of these acids can be used.

The binder resin has a softening point of 90 to 150 ° C., a glass transition point of 50 to 70 ° C., and a number average molecular weight of 2,000 to 6,
000, weight average molecular weight 8,000-150,000,
Those having an acid value of 5 to 30 and a hydroxyl value of 5 to 40 can be particularly preferably used.

In general, when a polyester resin is used as a binder resin for toner particles, the polyester resin itself has a negative charge property. It is said that it can be obtained. However, there is a drawback that the charging depends on the environment, that is, the difference in charge amount between high temperature and high humidity and low temperature and low humidity is large. This is particularly noticeable when a pigment other than carbon black is used as a colorant for the toner. In the present invention,
When a polyester resin is used, the above-mentioned disadvantages of the polyester resin are solved. Although the detailed mechanism is not clear, it is considered that the negative chargeability of the polyester resin is due to a carboxyl group or an ester bond which is a polar group of the polyester,
Since the chargeability of these polar groups is easily affected by changes in temperature and humidity, it is considered that even when the toner is formed into a toner, the chargeability is affected by changes in temperature and humidity. Further, it is impossible to remarkably improve the temperature and humidity change of charging by adding a charge controlling agent to the polyester resin. According to the present invention, a toner particle surface-treated with titanium oxide having a water-soluble component content of 0.2% by weight or less is externally added to the toner particles to maintain the charge amount of the toner necessary for development at high temperature and high humidity. It accelerates the uniformity of charge on the surface of toner particles and the charge exchange property between toner particles, improves the rise of charging, sharpens the distribution of charges, and consequently increases the environmental dependence of the charging amount. The width can be improved.

If necessary, a charge control agent, a fixing aid, a fluidity improver, a release agent, a cleaning aid, and the like can be added to the toner particles. For example, a polymethyl methacrylate resin, a polyvinylidene fluoride resin, a higher alcohol and the like can be used, and a commercially available charge control agent can be used.

The toner particles in the present invention are obtained by melt-kneading the above-mentioned colorant, binder resin and other components with a Banbury mixer, a CM mixer, an extruder or the like, pulverizing them with a jet pulverizer or the like, and then using an air classifier. And can be produced by classification. The weight average particle diameter of the toner particles is preferably in the range of 3 μm to 9.5 μm, particularly preferably in the range of 5 to 9.5 μm. When the average particle diameter is smaller than 3 μm, the developing property and toner scattering
It is difficult to achieve a good balance of powder characteristics. On the other hand, if it is larger than 9.5 μm, a high-quality image cannot be obtained.

Next, the surface-treated titanium oxide fine particles externally added to the toner particles will be described. In the present invention, as the surface-treated titanium oxide fine particles, the surface-treated titanium oxide fine particles (additive (A)) having an average particle diameter of 5 nm or more and less than 25 nm are used.
nm or less surface-treated titanium oxide fine particles (additive (B))
Is used. When two types of surface-treated titanium oxide fine particles having a particle diameter within the above range are externally added to toner particles, both fluidity and transferability can be satisfied simultaneously. That is, as the particle size of the toner particles becomes smaller, the non-electrostatic adhesion becomes relatively large, and as a result, the flowability is inevitably deteriorated. There must be. By the external addition of the additive, the adhesive force between the toner particles / toner particles is attenuated by the spacer effect, and the smoothness of the toner particle surface can be obtained.
It is necessary to use one having an average particle diameter of less than nm. If the average particle diameter is smaller than 5 nm, the spacer effect is almost eliminated, and the addition becomes meaningless.
If it is more than m, the smoothness of the toner particle surface will be lost just as the sandpaper count becomes small.
The most effective additive fine particles that contribute to the transferability have an average particle diameter of 25 to 80 nm, which is a larger particle diameter. When the particle diameter is in this range, the effect of improving the fluidity of the toner particles is small, but it is very effective in transferability. Since the transferability can be improved by reducing the adhesive force between the toner particles and the photosensitive member, it is considered that the transferability is improved by the spacer effect of the relatively large fine particles in the above range. If the average particle diameter is smaller than 25 nm, this effect will not be sufficient, and if the average particle diameter is larger than 80 nm, the adverse effect on the toner fluidity will be increased.

The titanium oxide fine particles, which are the core of the additive (A), preferably have a specific surface area in the range of 60 to 100 m ² / g, and particularly preferably have a specific surface area in the range of 75 to 95 m ² / g for improving the fluidity. Is preferred. When the specific surface area is less than 60 m ² / g, the fluidity is deteriorated. Also, 100m ² /
If it is larger than g, the photoconductor is liable to be damaged, and the image quality tends to deteriorate. Further, the water content of the Karl Fischer is preferably 5% by weight or less, particularly preferably 3.5% by weight or less from the viewpoint of long-term stability. If the water content of the Karl Fischer exceeds 5% by weight, the photoreceptor is likely to be damaged, and the image quality tends to deteriorate. The water content of the Karl Fischer can be reduced to 5% by weight or less by treating the titanium oxide fine particles at a high temperature of 300 ° C. or higher for 30 minutes or longer.

The specific surface area means a BET specific surface area and is a value measured by a nitrogen adsorption method. For example,
It can be measured using a flow-type nitrogen adsorption BET one-point method using a Cantasorb QS-16 (manufactured by Kantachrome). That is, the sample was degassed at 200 ° C. for 15 minutes under a N ₂ 100% gas flow, the sample was cooled to liquid nitrogen temperature, and a He / N ₂ (N ₂ 30%) mixed gas was flowed to adsorb N _2. After that, the N ₂ adsorbed at room temperature is desorbed,
The desorbed N ₂ was determined by a thermal conductivity detector, and the calculated total surface area was expressed as a ratio to 1 g of the dry mass of the sample. The water content of the Karl Fischer was measured by a constant voltage polarization voltage titration method using a Karl Fischer titrator. For example, a volumetric titration type moisture analyzer K manufactured by Mitsubishi Kasei Corporation
It can be measured by F-06 type. That is,
Using a microsyringe, 10 μl of pure water is precisely weighed, and the water content (mg) per 1 ml of the Karl Fischer reagent is calculated from the amount of reagent required for removing this water. Next, 100 to 200 mg of the measurement sample is precisely weighed and sufficiently dispersed by a magnetic stirrer in the measurement flask for 5 minutes. After the dispersion, the measurement is started, the titration amount (ml) of the Karl Fischer reagent required for the titration is integrated, and the water content and the water content are calculated by the following formula, and the Karl Fischer water content is expressed by the water content. is there. Water content (mg) = reagent consumption (ml) x reagent titer (mg
H ₂ O / ml) water content (%) = [water content (mg) / sample amount (m
g)] × 100

The crystalline titanium oxide fine particles constituting the additive (A) in the present invention must be produced by a wet method and have a water-soluble component content of 0.2% by weight or less. When the amount of the water-soluble component is more than 0.2% by weight, the charge amount is low as in the case of the conventional titanium oxide, and the surface treatment is still insufficient. However, when the amount of the water-soluble component is 0.2% by weight or less, the charge amount increases, and when the surface treatment described in detail below is performed,
A higher charge amount is maintained. The reason is considered as follows. Titanium oxide is essentially insoluble in water and has no water-soluble components. However, in the titanium oxide produced by the wet method, it is inevitable that a trace amount of a water-soluble component remains from the production process. The water-soluble components include the chemicals used in the production process and the coagulants K ⁺ , Na ⁺ , Li ⁺ , Mg ²⁺ , PO ₄
^2- , SO ₄ ^2- , Cl- ^{and the} like. From the viewpoint of chargeability, it is considered that this water-soluble component lowers the chargeability of titanium oxide. It has been considered that the chargeability is conventionally affected by the environment of the contact charge and the electric resistance of the material itself.If the water-soluble component remains in the titanium oxide powder, it is easy to attract water, and the natural resistance decreases. The charge amount decreases. Therefore, if the water-soluble component is removed or reduced, the resistance increases and a high charge amount is maintained. The measurement of the amount of the water-soluble component is in accordance with JIS (JIS K5116-197).
3) 5 g of the pigment is boiled in 250 ml of water, filtered after cooling, 100 ml of the filtrate is taken off, evaporated to dryness and the remaining amount is weighed and expressed as% of the original pigment.

Here, the wet method is a method of purification through a chemical reaction or crystal growth in a liquid phase, and the main production methods are a sulfuric acid method and a hydrochloric acid method. The sulfuric acid method dissolves ilmenite ore with sulfuric acid. The following reaction proceeds in the liquid phase to form insoluble titanium oxide. This hydrous titanium oxide is calcined to obtain crystalline titanium oxide fine particles. FeTiO ₃ + 2H ₂ SO ₄ → FeSO ₄ + TiOSO
₄ + 2H ₂ O TiOSO ₄ + 2H ₂ O → TiO (OH) ₂ + H ₂ SO
_{In the 4-} hydrochloric acid method, when TiCl ₄ is first dissolved in water, a state of an aqueous hydrochloric acid solution is obtained. Fine titanium oxide is added as a seed to this, and a crystal is grown using the seed as a nucleus.
H) Removed as ₄ . The titanium hydroxide is fired to obtain crystalline titanium oxide fine particles. The crystalline titanium oxide fine particles can also be produced by a wet method in which a titanium alkoxide is heated and evaporated and thermally decomposed at a temperature of 250 to 600 ° C. in the presence of a catalyst and moisture. In the above wet method, control of pH, reaction temperature,
By adjusting the particle size by controlling the reaction time, etc.,
The specific surface area can be controlled. In addition, the specific surface area can be increased by pulverizing into amorphous particles.

In the present invention, the crystalline titanium oxide fine particles need to be surface-treated. By performing the surface treatment, an appropriate charge amount is secured, and further, the occurrence of comet and filming can be prevented. Examples of the treating agent used for the surface treatment include a silane coupling agent, silicone oil, a titanium-based coupling agent, an aluminate-based coupling agent, and a zirconium-based coupling agent. I)-(II
The silicon compounds and silicone oils represented by I) are used. R ¹ Si (X) ₃ (I) R ¹ R ² Si (X) ₂ (II) R ¹ R ² R ³ SiX (III) (wherein, R ¹ is an alkyl group having 1 to 20 carbon atoms or Represents a fluoroalkyl group, R ² and R ³ represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a perfluoroalkyl group, or an aryl group, respectively, and X represents a chlorine atom, an alkoxy group, an NCO group, or an acetoxy group. Represents a group.)

Specifically, the following compounds can be exemplified. As the compound represented by the formula (I), CH ₃ S
i (Cl) ₃ , CH ₃ Si (OCH ₃ ) ₃ , CH ₃ Si
(OC ₂ H ₅ ) ₃ , CH ₃ CH ₂ Si (OCH ₃ ) ₃ ,
CH ₃ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ , CH ₃ (CH
₂ ) ₃ Si (OCH ₃ ) ₃ , CH ₃ (CH ₂ ) ₄ Si
(OCH ₃ ) ₃ , CH ₃ (CH ₂ ) ₅ Si (OCH ₃ )
₃ , CH ₃ (CH ₂ ) ₆ Si (OCH ₃ ) ₃ , CH
₃ (CH ₂ ) ₇ Si (OCH ₃ ) ₃ , CH ₃ (CH ₂ )
₈ Si (OCH ₃ ) ₃ , CH ₃ (CH ₂ ) ₉ Si (OC
_{H 3) 3, CH 3 (} CH 2) 10 Si (OCH 3) 3, C
H ₃ (CH ₂ ) ₁₁ Si (OCH ₃ ) ₃ , CH ₃ (C
H ₂ ) ₁₂ Si (OCH ₃ ) ₃ , CH ₃ (CH ₂ ) ₁₃ Si
(OCH ₃ ) ₃ , CH ₃ (CH ₂ ) ₁₄ Si (OCH ₃ )
₃ , CH ₃ (CH ₂ ) ₁₅ Si (OCH ₃ ) ₃ , CH
₃ (CH ₂ ) ₁₆ Si (OCH ₃ ) ₃ , CH ₃ (CH ₂ )
₁₇ Si (OCH ₃ ) ₃ , CH ₃ (CH ₂ ) ₁₈ Si (OC
_{H 3) 3, CH 3 (} CH 2) 19 Si (OCH 3) 3, C
H ₃ (CH ₂ ) ₅ Si (OC ₂ H ₅ ) ₃ , CH ₃ (CH
₂ ) ₆ Si (OC ₂ H ₅ ) ₃ , CH ₃ (CH ₂ ) ₇ Si
(OC ₂ H ₅ ) ₃ , CH ₃ (CH ₂ ) ₈ Si (OC ₂ H
₅ ) ₃ , CH ₃ (CH ₂ ) ₉ Si (OC ₂ H ₅ ) ₃ , C
H ₃ (CH ₂ ) ₁₀ Si (OC ₂ H ₅ ) ₃ , CH ₃ (CH
₂ ) ₁₁ Si (OC ₂ H ₅ ) ₃ , CH ₃ (CH ₂ ) ₁₂ Si
(OC ₂ H ₅ ) ₃ , CH ₃ (CH ₂ ) ₁₃ Si (OC ₂ H
₅ ) ₃ , CH ₃ (CH ₂ ) ₁₄ Si (OC ₂ H ₅ ) ₃ , C
H ₃ (CH ₂ ) ₁₅ Si (OC ₂ H ₅ ) ₃ , CH ₃ (CH
₂ ) ₁₆ Si (OC ₂ H ₅ ) ₃ , CH ₃ (CH ₂ ) ₁₇ Si
(OC ₂ H ₅ ) ₃ , CH ₃ (CH ₂ ) ₁₈ Si (OC ₂ H
₅ ) ₃ , CH ₃ (CH ₂ ) ₁₉ Si (OC ₂ H ₅ ) ₃ , C
Examples include F ₃ Si (OCH ₃ ) ₃ and CH ₃ Si (NCO) ₃ .

The compound represented by the formula (II) includes (C
H ₃ ) ₂ SiCl ₂ , (CH ₃ ) ₂ Si (OC
_{H 3) 2, (CH 3} ) 2 Si (OC 2 H 5) 2, (CH
₃ ) (CH ₃ CH ₂ ) Si (OCH ₃ ) ₂ , (CH ₃ )
[CH ₃ (CH ₂ ) ₂ ] Si (OCH ₃ ) ₂ , (C
H ₃ ) [CH ₃ (CH ₂ ) ₃ ] Si (OCH ₃ ) ₂ ,
(CH ₃ ) [CH ₃ (CH ₂ ) ₄ ] Si (OC
H ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₅ ] Si (O
CH ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₆ ] Si
(OCH ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₇ ] S
i (OCH ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₈ ]
Si (OCH ₃ ) ₂ , (CH ₃ ) [CH ₃ (C
H _{2) 9] Si (OCH 3) 2, (} CH 3) [CH
₃ (CH ₂ ) ₁₀ ] Si (OCH ₃ ) ₂ , (CH ₃ ) [C
H ₃ (CH ₂ ) ₁₁ ] Si (OCH ₃ ) ₂ , (CH ₃ )
[CH ₃ (CH ₂ ) ₁₂ ] Si (OCH ₃ ) ₂ , (C
H ₃ ) [CH ₃ (CH ₂ ) ₁₃ ] Si (OCH ₃ ) ₂ ,
(CH ₃ ) [CH ₃ (CH ₂ ) ₁₄ ] Si (OC
H ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₁₅ ] Si (O
CH ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₁₆ ] Si
(OCH ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₁₇ ] S
i (OCH ₃ ) ₂ , (CH ₃ ) [CH ₃ (CH ₂ ) ₁₈ ]
Si (OCH ₃ ) ₂ , (CH ₃ ) [CH ₃ (C
H ₂ ) ₁₉ ] Si (OCH ₃ ) ₂ , (CH ₃ ) ₂ Si (N
CO) _{2 and the} like.

As the compound represented by the formula (III),
(CH ₃ ) ₃ SiCl, (CH ₃ ) ₃ Si (OC
H ₃ ), (CH ₃ ) ₃ Si (OC ₂ H ₅ ), (CH ₃ )
₂ (CH ₃ CH ₂ ) Si (OCH ₃ ), (CH ₃ )
₂ [CH ₃ (CH ₂ ) ₂ ] Si (OCH ₃ ), (C
H ₃ ) ₂ [CH ₃ (CH ₂ ) ₃ ] Si (OCH ₃ ),
(CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₄ ] Si (OC
H ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₅ ] Si (O
CH ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₆ ] Si
(OCH ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₇ ] S
i (OCH ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₈ ]
Si (OCH ₃ ), (CH ₃ ) ₂ [CH ₃ (C
H _{2) 9] Si (OCH 3), (CH} 3) 2 [CH
₃ (CH ₂ ) ₁₀ ] Si (OCH ₃ ), (CH ₃ ) ₂ [C
H ₃ (CH ₂ ) ₁₁ ] Si (OCH ₃ ), (CH ₃ )
₂ [CH ₃ (CH ₂ ) ₁₂ ] Si (OCH ₃ ), (C
H ₃ ) ₂ [CH ₃ (CH ₂ ) ₁₃ ] Si (OCH ₃ ),
(CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₁₄ ] Si (OC
H ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₁₅ ] Si (O
CH ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₁₆ ] Si
(OCH ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₁₇ ] S
i (OCH ₃ ), (CH ₃ ) ₂ [CH ₃ (CH ₂ ) ₁₈ ]
Si (OCH ₃ ), (CH ₃ ) ₂ [CH ₃ (C
H ₂ ) ₁₉ ] Si (OCH ₃ ). Among these, those represented by the above formula (I) are preferable in terms of increase in the amount of charge, and in particular, CH ₃ (CH ₂ ) _n Si (O
CH ₃ ) ₃ (where n = 5 to 19) is preferred. Further, for the same reason, it is preferable that R ¹ represents an alkyl group having 7 to 16 carbon atoms or a perfluoroalkyl group.
Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, and the like, and other modified silicone oils. If necessary, a plurality of coupling agents and silicone oils can be used in combination.

The treatment with the coupling agent may be performed, for example, by immersing the titanium oxide fine particles in a solution containing the coupling agent and drying the solution, or by spraying a solution containing the coupling agent on the titanium oxide fine particles and drying. It can be performed by a method or the like. However, the former method, that is, a method in which the titanium oxide fine particles are immersed in a solution containing a coupling agent and then dried is preferable because a uniform coating can be formed. The amount of the coupling agent is 0.1 to 25 with respect to the titanium oxide fine particles.
% By weight.

The electrophotographic toner composition of the present invention can be produced by mixing the toner particles with the additives (A) and (B) using a Henschel mixer or a V blender. In the present invention, the compounding ratio of the above additive (A) and additive (B) needs to be in the range of 1: 2 to 3: 1 by weight. By setting the ratio of the additive (A) and the additive (B) in the above range, it is possible to achieve both improvement in powder fluidity, improvement in transferability, and prevention of comet and filming. Further, the additive (A) is used for the toner particles.
It is necessary that the content be 0.6% by weight or more and 4.0% by weight or less. If the content of the additive (A) is lower than 0.6% by weight, the powder properties deteriorate, and if it is higher than 4.0% by weight, comet or filming is liable to occur on the photoreceptor. It is desirable that the total amount of the additive (A) and the additive (B) is in the range of 1.0% by weight to 4.0% by weight based on the toner particles. If the amount is less than 1.0% by weight, the powder characteristics and the heat cohesiveness are deteriorated. If the amount exceeds 4.0% by weight, comet or filming may occur. In the present invention, other additives such as silica and alumina can be used in combination with the toner particles, if necessary.
To the toner composition of the present invention, olefin wax such as polyethylene wax or polypropylene wax, carnauba wax, and Unilin (manufactured by Toyo Petrolite Co., Ltd.) can be further added to improve the cleaning property.

The electrophotographic toner composition of the present invention is used as a mixture with a carrier. As the carrier, iron powder, glass beads, ferrite powder, nickel powder, or a resin coating is applied to the surface thereof. Things are used. The mixing ratio with the carrier can be set as appropriate.

The image forming method of the present invention using the above-described electrophotographic toner composition comprises the steps of forming an electrostatic latent image on a latent image carrier, and using a developer layer formed on the developer carrier. In this step, a known method used in electrophotography can be employed.

[0034]

In the following, "parts" means parts by weight. Example 1 and Comparative Example 1 (1) Preparation of toner particles Toner particles (A) 100 parts of styrene-n-butyl methacrylate copolymer (copolymerization ratio: 80:20) (Tg: 62 ° C., Mn: 12,000) , Mw: 32,000) Carbon black (# 25: manufactured by Mitsubishi Kasei Co., Ltd.) 5 parts The above mixture was kneaded with an extruder, pulverized with a jet mill, and then classified with a wind-type classifier to obtain an average particle diameter of 6 μm.
m (d50 vol) of black toner particles were obtained. Toner particles (B) 100 parts of polyester resin (terephthalic acid-bisphenol A ethylene oxide adduct-linear polyester obtained from cyclohexanedimethanol) (Tg: 62 ° C., Mn: 4,000, Mw: 35,000, Acid value: 8, hydroxyl value: 15) Cyan colorant (CI Pigmentable-15: 3) 4 parts The above mixture is kneaded with an extruder, pulverized with a jet mill, and classified with a wind-type classifier. , Average particle size 7μ
m (d50 vol) of cyan toner particles were obtained.

(2) Preparation of Additives Additives (a) to (g) were prepared using the additives shown in Table 1 below as additive cores and treating agents for surface treatment. The surface treatment of the additive core was performed as follows. That is, the treating agents shown in Table 1 were replaced with toluene-water (9
5: 5) in the mixed solvent, based on the additive core weight,
And the additive core was added thereto, and ultrasonic dispersion treatment was performed. Next, toluene and the like in the dispersion liquid were evaporated by an evaporator, dried,
Was heat-treated in a drier set in Example 1, and crushed with a mortar to obtain surface-treated additives (a) to (g).

[0036]

[Table 1]

(3) Preparation of toner composition Toner particles (A) and (B) and additives (a) to (g)
Are used in combinations shown in Table 2 below, and mixed in the mixing amounts shown in Table 2 with a high-speed mixer to obtain a toner composition (1).
To (14) were obtained.

[Table 2]

(4) Preparation of Developer Ferrite coated with a styrene-methyl methacrylate copolymer and having a particle diameter of about 50 μm was used as a carrier, and the above toner compositions (1) to (1) were used for 100 parts of the carrier. 8) was added. Then, the mixture was mixed in a V blender at 40 rpm for 20 minutes, and the obtained developers (1) to (14) were subjected to high temperature and high humidity (30 ° C., 8
5%) and low temperature and low humidity (10 ° C., 30% RH). Table 3 shows the results.

(Copy Test (1)) Next, a copy test was performed using A-color 630 (manufactured by Fuji Xerox Co., Ltd.) using the above-mentioned developers (1) to (14). In the copy test, low temperature and low humidity (10 ° C, 30% R
H) 1 to 5,000 sheets, high temperature and high humidity (30 ° C, 85% R)
H), 500 to 10,000 copies were made. Table 3 shows the results. In the comprehensive evaluation, ○ means no problem at all, good, △ means somehow usable, and × means not usable.

[0040]

[Table 3]

(Copy Test (2)) The developers (7), (9) and (14) which were stable in the copy test (1) were treated in an environment of 10 ° C. and 10% RH.
Similarly, a copy test of 10,000 sheets was performed using A-color 630 (manufactured by Fuji Xerox). As a result, in the case of the developer (7), from 5,000 sheets to 8.0
The toner density in the developer in the copying machine is 1
Up to 2%, slight soiling was observed. Also,
In the case of the developers (9) and (14), the toner concentration was always 10% or less, and the image quality was stable.

Example 2 (1) Preparation of Toner Particles Toner particles (C) 100 parts of styrene-n-butyl methacrylate copolymer (copolymerization ratio: 75:25) (Tg: 65 ° C., Mn: 15,000, Mw: 35,000) Magenta pigment (CI Pigment Red 57) 3 parts Potassium tetraphenylborate 1 part The above mixture was kneaded with an extruder, pulverized with a jet mill, and classified with a wind-type classifier. Average particle size 5μ
m (d50 vol) of magenta toner particles were obtained. Toner particles (D) 100 parts of linear polyester resin (Linear polyester obtained from ethylene oxide adduct of terephthalic acid-bisphenol A-cyclohexanedimethanol) (Tg: 62 ° C, Mn: 4,000, Mw: 35, 000, Acid value: 12, Hydroxyl value: 25) Magenta pigment (CI Pigment Red 57) 3 parts The above mixture was kneaded with an extruder, pulverized with a jet mill, and classified with a wind-type classifier. Average particle size 5μ
m (d50 vol) of magenta toner particles were obtained.

(2) Preparation of Additive Additive (h) 1 g of CH ₃ Si (OCH ₃ ) ₃ was dissolved in a mixed solvent consisting of 95 parts of methanol and 5 parts of water, and the particle size was produced by a wet method. 15 nm rutile-type titanium oxide (MT-150
A, manufactured by Teica Co.) and washed with water to reduce the amount of water-soluble components to 0.11.
10 g of a fine powder in an amount of 10% by weight was added, and the mixture was ultrasonically dispersed to subject the titanium oxide particles to a surface treatment to form an alkyl group on the surface. After evaporating methanol and the like with an evaporator, the mixture was dried, heat-treated with a dryer set at 120 ° C., and pulverized with a mortar to obtain an additive (h). Additive (i) After dissolving 2 g of C ₁₀ H ₂₁ Si (OCH ₃ ) _{3 in} a mixed solvent consisting of 95 parts of methanol and 5 parts of water, a rutile type titanium oxide (MT) having a particle size of 15 nm produced by a wet method was used. -15
0A, manufactured by Teica Co., Ltd.)
10 g of a 8% by weight fine powder is added, and the surface of the titanium oxide particles is treated by ultrasonic dispersion to form C ₁₀ H ₂₁ Si (O
CH ₃ ) ₃ was deposited. Hereinafter, an additive (i) was obtained in the same manner as in the case of the additive (h).

Additive (j) Silicone oil (KF99, manufactured by Shin-Etsu Chemical Co., Ltd.) 2.0 g
Was dissolved in toluene, and the particle size of 15 produced by the wet method was used.
nm of rutile-type titanium oxide (MT-150A, manufactured by Teica) was washed with water, and 10 g of fine powder having a water-soluble component content of 0.13% by weight was added thereto. Attached. After evaporating toluene with an evaporator, the toluene was dried, heat-treated with a dryer set at 140 ° C., and pulverized with a mortar to obtain an additive (j). Additive (k) In the additive (i), a rutile-type titanium oxide having a particle size of 15 nm, a rutile-type titanium oxide having a particle size of 35 nm (MT-500B, manufactured by Teica) washed with water (water) The amount of the soluble component was changed to 0.08% by weight, and C ₁₀ H ₂₁
An additive (k) was obtained in the same manner except that the amount of Si (OCH ₃ ) ₃ was changed to 1 g. Additive (l) Additive (k) obtained by washing a rutile-type titanium oxide having a particle diameter of 35 nm (MT-600B, manufactured by Teica) manufactured by a wet method with a particle diameter of 50 nm (water) Except that the amount of the soluble component was changed to 0.06% by weight)
The same treatment was performed to obtain an additive (l). The details of the additives (h) to (l) are shown in Table 4 below.

(3) Preparation of toner composition Toner composition (15) To 100 parts by weight of toner particles (C), 2 parts and 3 parts of additives (h) and (k) were added, respectively, and mixed by a high-speed mixer. Thus, a toner composition (15) was obtained. Toner composition (16) To 100 parts by weight of toner particles (D), 2 parts and 3 parts of additives (i) and (k) are added, respectively, and mixed by a high-speed mixer to obtain toner composition (16). Was. Toner Composition (17) To 100 parts by weight of the toner particles (D), 1.8 parts and 3 parts of the additives (i) and (l) are added, respectively, and mixed by a high-speed mixer to obtain a toner composition (17). I got Toner composition (18) To 100 parts by weight of the toner particles (D), 1.8 parts and 3 parts of the additives (j) and (l) are added, respectively, and mixed by a high-speed mixer to obtain a toner composition (18). I got Toner composition (19) To 100 parts by weight of toner particles (D), 1.8 parts and 3 parts of additives (j) and (l) are added, respectively, and silica fine powder (R812, manufactured by Nippon Aerosil Co., Ltd.) is added. 4 parts were added and mixed with a high-speed mixer to obtain a toner composition (1).
9) was obtained.

(4) Preparation of Developer The above-mentioned toner compositions (15) to (19) and styrene-
Particle size of about 5 coated with methyl methacrylate copolymer
Using a carrier of 0 μm ferrite, 5 parts of each of the above toner compositions were added to 100 parts of the carrier, and mixed with a tumbler shaker mixer to prepare a developer for evaluation.

Using these developers, a copy test was performed by an electrophotographic copying machine (A-Clor 630, manufactured by Fuji Xerox Co., Ltd.), and a high temperature and high humidity (30 ° C., 85%) and a low temperature and low humidity (10 ° C., 15%) were used. % RH), the charge amount, the charge distribution, and the reverse polarity toner amount were measured. Note that the charge amount is a value obtained by image analysis of CSG (charge spectrograph method), and the charge distribution is represented by 20% charge amount Q (20) and 80% charge amount Q
It is defined as a value obtained by dividing the difference of (80) by the 50% charge amount Q (50), that is, {Q (80) −Q (20)} / Q (50). The results obtained are shown in Table 5 below.

Comparative Example 2 (1) Preparation of Additive Additive (m) Titanium oxide (MT-150A) which was not washed with water and had a water-soluble component content of 0.30% by weight. )) And treated under the same conditions as in the
I got Additive (n) The titanium oxide (MT-150A) was washed with water to obtain an additive (n) having a water-soluble component amount of 0.12% by weight. The details of the additives (m) and (n) and R812, R972 and T805 used for comparison are shown in Table 4 below.

(2) Production of Toner Composition Toner composition (20) and (21) To 100 parts by weight of toner particles (C) and (D) of Example 2, 3 parts of additive (i) were added, respectively. The mixture was mixed with a high-speed mixer to obtain toner compositions (20) and (21). Toner Composition (22) To 100 parts by weight of the toner particles (D) of Example 2, only 1 part of hydrophobic silica fine powder (R972, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter of 16 nm was added and mixed by a high-speed mixer. Thus, a toner composition (22) was obtained. Toner composition (23) 1 part of hydrophobic silica fine powder (R972, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter of 16 nm and 2 parts of additive (k) were added to 100 parts by weight of toner particles (D) of Example 2. Then, the mixture was mixed by a high-speed mixer to obtain a toner composition (23). Toner Composition (24) To 100 parts by weight of the toner particles (D) of Example 2, 2 parts of the additive (m) was added and mixed by a high-speed mixer to obtain a toner composition (24). Toner Composition (25) To 100 parts by weight of the toner particles (D) of Example 2, 1 part of surface-treated titanium oxide (T805) of titanium oxide (P-25, manufactured by Nippon Aerosil Co., Ltd.) produced by a dry method was added. And
The mixture was mixed with a high-speed mixer to obtain a toner composition (25). Toner Composition (26) To 100 parts by weight of the toner particles (D) of Example 2, only 1 part of the additive (n) was added and mixed by a high-speed mixer to obtain a toner composition (26). Toner composition (27) To 100 parts by weight of the toner particles (D) of Example 2, only 3 parts of the additive (l) were added and mixed by a high-speed mixer to obtain a toner composition (27).

Evaluation was carried out in the same manner as in Example 2 using these toner compositions and the same carrier as in Example 2.
The results are shown in Table 5 below. Also, A-Color 63
Table 5 also shows the results of fogging and solid image density of the copy after 1000 copies using 0. The environment at this time is normal temperature and normal humidity (22 ° C., 55% RH). In addition, fog is a sensory evaluation by visual inspection.
Those that could be easily confirmed were marked with x, and the middle was marked with △. Solid image density is X-Rite "R" 404 (X-Rit
e company).

[0051]

[Table 4]

[0052]

[Table 5]

As is clear from the results shown in Table 5, when the toner compositions (15) to (19) of the present invention were used, the charge amount hardly changed even at low and low humidity and high and high humidity. Also, the distribution of the charge amount was very sharp.
A copy test of 10,000 sheets was performed using these toner compositions. As a result, a slight in-machine stain was observed in the toner composition (19). And a stable image was obtained.

On the other hand, in the toner composition to which only titanium oxide having a small average particle diameter was added, the image density was generally low. This is due to poor transferability. Further, in the toner composition to which only titanium oxide having a large average particle diameter was added, unevenness of the image density was generally observed, and the image density was not stable. This is because the fluidity of the toner is not good and the stirring with the carrier has not been performed well. When only hydrophobic silica was added, the charge amount was originally large, the charge amount was largely fluctuated due to changes in the environment, and the charge amount distribution was wide. Therefore, the image density was low. In addition, when surface treatment was performed, when titanium oxide having a water-soluble content of 0.30% by weight was added, the charge amount was low, and background staining was generated from the beginning. Further, when titanium oxide which had a water-soluble content of 0.12% by weight but was not subjected to surface treatment was added, the charge amount was extremely low and the reverse polarity toner amount was large, so that it could not withstand use.

Example 3 97 parts of styrene-n-butyl methacrylate copolymer (copolymerization ratio: 70:30) (Mn: about 7,000, Mw: about 40,000) Cyan pigment (β-type phthalocyanine: 3 parts) CI Pigment Blue 15: 3) The mixture was melt-kneaded, finely pulverized and classified to obtain cyan toner particles having an average particle diameter of 5.3 μm (d50 vol). To 100 parts by weight of the cyan toner particles, 1.5 parts of the additive (i) and 3 parts of the additive (l) used in Example 2 were added and mixed by a high-speed mixer.
A cyan composition was obtained. The toner particles of this cyan composition exhibited good fluidity. 6 parts of the above cyan toner composition was mixed with 100 parts of a carrier obtained by coating a styrene-methyl methacrylate copolymer with ferrite having a particle size of about 50 μm to obtain a developer. Using this developer, a copying test was performed by a copying machine (A-Color630, manufactured by Fuji Xerox Co., Ltd.).
Under the conditions from 5% RH) to low temperature and low humidity (10 ° C., 15% RH), the background portion was free from stains, and high-quality images with high density were obtained from the beginning. Further, continuous copying of 10,000 sheets showed little change in image quality.

Examples 4 and 5 3 parts of the cyan pigment of Example 3 were replaced with a magenta pigment (Brilliant Carmine 6BC: CI Pigment Red 5).
7) 3 parts, and a yellow pigment (disazo yellow:
C. I. Pigment Yellow 12) was replaced with 3 parts, and magenta toner particles and yellow toner particles having an average particle diameter of 5.2 μm were obtained in the same manner. An additive was added to 100 parts of the above magenta toner particles and 100 parts of the yellow toner particles in the same manner as in Example 3, and mixed by a high-speed mixer to obtain a magenta toner composition and a yellow toner composition. These toner compositions exhibited good fluidity. A developer was prepared in the same manner as in Example 3, and a copying test was performed in the same manner. As a result, under the conditions of high temperature and high humidity to low temperature and low humidity, a high-density and high-quality image was obtained without stain on the background. . Further, continuous copying of 10,000 sheets showed little change in image quality.

[0057]

According to the present invention, as described above, by adding two surface-treated titanium oxide fine particles having different average particle diameters as additives, the powder characteristics, transferability and cleaning property of the toner are improved. Thus, the occurrence of comet and filming caused by the cleaning blade on the surface of the photoconductor is prevented. Further, the present invention has an excellent effect that the chargeability is excellent, especially the environment dependency of the charge is good, and the charge exchangeability is improved to prevent the toner from scattering at the time of toner supply. In addition, even when used continuously for a long period of time, it is possible to obtain a high-definition copy image having a stable image density while maintaining an appropriate charge amount, generating little reverse polarity toner, and having no fog.

──────────────────────────────────────────────────続 き Continued on the front page (72) Michio Take, 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Masahiro Takagi 1600 Takematsu, Takematsu, Minami-Ashigara, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72 ) Inventor Hiroshi Takano 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Masaki Hashimoto 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (56) References JP, A) JP-A-4-335357 (JP, A) JP-A-2-43563 (JP, A) JP-A-6-208241 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , (DB name) G03G 9/08 G03G 9/113

Claims (7)

(57) [Claims] 1. An electrophotographic toner composition comprising a toner particle containing a colorant and a binder resin and an additive, wherein the additive is surface-treated titanium oxide fine particles,
It contains small-sized fine particles having an average particle size of 5 nm or more and less than 25 nm and large-sized fine particles having an average particle size of 25 nm or more and 80 nm or less, and the weight ratio of the small-sized fine particles to the large-sized fine particles is 1: 2 to 3. : 1 in an amount of 0.6% by weight or more based on the toner.
A toner composition for electrophotography, wherein the content is 0% by weight or less, titanium oxide is produced by a wet method, and the amount of water-soluble component is 0.2% by weight or less. 2. The toner particles have an average particle diameter of 3 μm or more,
The electrophotographic toner composition according to claim 1, wherein the thickness is 9.5 μm or less. 3. Small particles having an average particle diameter of not less than 5 nm and less than 25 nm have a specific surface area of not less than 60 m ² / g and not more than 100 m ^2.
2. The electrophotographic toner composition according to claim 1, wherein the toner composition has a Karl Fischer water content of 5% by weight or less. 4. The method according to claim 1, wherein the additive has the following formula (I) to (III):
2. The electrophotographic toner composition according to claim 1, wherein the toner composition is surface-treated with a silicon compound or silicone oil represented by the formula: R ¹ Si (X) ₃ (I) R ¹ R ² Si (X) ₂ (II) R ¹ R ² R ³ SiX (III) (wherein, R ¹ is an alkyl group having 1 to 20 carbon atoms or Represents a fluoroalkyl group, R ² and R ³ represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a perfluoroalkyl group, or an aryl group, respectively, and X represents a chlorine atom, an alkoxy group, an NCO group, or an acetoxy group. Represents a group.) 5. The electrophotographic toner composition according to claim 1, wherein the binder resin of the toner particles is a polyester resin. 6. An electrophotographic developer comprising an electrophotographic toner composition and a resin-coated carrier, wherein the electrophotographic toner composition is the electrophotographic toner composition according to claim 1 and a resin-coated carrier. Is a carrier coated with an acrylic resin. 7. The electrophotographic toner composition according to claim 1, wherein the image forming method comprises a step of forming an electrostatic latent image on the latent image carrier and a step of developing the formed electrostatic latent image. An image forming method comprising: forming a developer layer containing a developer on a developer carrier; and performing development.