JPH05119517A - Toner - Google Patents

Abstract

PURPOSE:To stabilize electrification in various environments and to obtain high fluidity and high picture quality by improving oxide fine particles, especially, by using titanium oxide treated with a coupling agent having specified structure. CONSTITUTION:This toner contains titanium oxide and has 5-10mum weight mean particle size. This titanium oxide is subjected to surface treatment with silicone oil or silicone varnish in a water medium and then subjected to hydrolysis treatment with a coupling agent expressed by formula I in a water medium. In formula 1, (n) is an integer 4-12 and (m) is an integer 1-3. The amt. of silicone oil or silicone varnish used for treatment is 0.1-10 pts.wt. to 100 pts.wt. of titanium oxide. The amt. of coupling agent for the treatment is 5-30 pts.wt. to 100 pts.wt. of titanium oxide. The titanium oxide has 0.01-0.2mum average particle size. 40-80% hydrophobicity and >=40% transmittance for 400mum light. Thereby, the obtd. toner gives clear picture image characteristics without fogging and has excellent durability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a toner for developing an electrostatic charge image in electrostatic printing or the like.

[0002]

BACKGROUND OF THE INVENTION The formation and development of images on the surface of photoconductive materials by electrostatic means is well known in the art.

That is, US Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-2.
Although a number of methods are known, such as Japanese Patent No. 4748, a photoconductive substance is generally used to form an electric latent image on a photoconductor by various means, and then it is called a toner on the latent image. A toner image corresponding to an electrostatic latent image is formed by adhering a very finely ground electrophotographic material.

Then, if necessary, the toner is transferred onto the surface of an image support such as paper and then fixed by heating, pressurizing or solvent vapor to obtain a copy. Further, when there is a step of transferring the toner image, a step for removing the residual toner is usually provided.

A developing method for visualizing an electric latent image using a toner is, for example, a powder cloud method described in US Pat. No. 2,221,776 and 2,618,55.
No. 2 specification, cascade development method, No. 2,874,063 specification, magnetic brush method, and No. 3,909,258 description, conductivity. A method using a magnetic toner is known.

As the toner applied to these developing methods, a toner obtained by mixing and dispersing a colorant in a thermoplastic resin and then pulverizing it is generally used. Polystyrene resin is the most common thermoplastic resin, but polyester resin, epoxy resin, acrylic resin, urethane resin, etc. are also used. Carbon black is most widely used as the colorant, and iron oxide-based black magnetic powder is often used in the case of magnetic toner. In the case of a system using a so-called two-component developer, the toner is usually glass beads,
It is used as a mixture with carrier particles such as iron powder.

The toner image on the final copy image forming member such as paper is permanently fixed on the support by heat, pressure or the like. Conventionally, this fixing process is often performed by heat.

When the method has a step of transferring a toner image, it usually has a step for removing the residual toner on the photoconductor.

In recent years, the development from mono-color copying to full-color copying is rapidly progressing in copying machines and the like, and the study and practical application of two-color copying machines and full-color copying machines have been made significantly. For example, "Journal of the Electrophotographic Society" Vol
22, No. 1 (1983) and "Electronic Photography Society" Vo
l 25, No. 1, P52 (1986), there are reports of color reproducibility and gradation reproducibility.

However, it is not immediately compared with the real thing like a TV, a photograph, a color printed matter, and for people who can see a color image which is more beautifully processed than the real thing, the full-color electrophotography currently in practical use. The images are not always satisfactory.

In color image formation by full-color electrophotography, all the colors are reproduced using color toners of three primary colors, yellow, magenta and cyan.

In the method, first, light from the original is passed through a color separation light transmitting filter having a complementary color relationship with the color of the toner to form an electrostatic latent image on the photoconductive layer, and then the toner is subjected to development and transfer steps to remove the toner. Hold on a support. This step is sequentially performed a plurality of times, and the toners are overlaid on the same support while matching the registration, and then the fixing process is performed once to obtain a final full-color image.

Generally, in the case of a so-called two-component developing system in which the developer is composed of toner and carrier, the developer charges the toner to a required charge amount and charge polarity by friction with the carrier and utilizes electrostatic attraction. Then, the electrostatic image is developed, and therefore, in order to obtain a good visible image, it is necessary that the triboelectric chargeability of the toner, which is mainly determined by the relationship with the carrier, is good.

To solve the above-mentioned problems, the search for carrier core agents and carrier coating agents and the optimization of the coating amount, or the examination of charge control agents and fluidity imparting agents to be added to the toner, and the binder serving as the base material, are conducted today. Many studies have been conducted to achieve excellent triboelectrification properties in all materials constituting the developer, including improvements in the above.

For example, as a technique for adding a charging auxiliary agent such as charging fine particles to a toner, Japanese Patent Publication No. 52-32256
JP-A-56-64352 and JP-A-56-64352 add resin fine powder having a polarity opposite to that of the toner, and JP-A-61-160760 adds a fluorine-containing compound to the developer.
A technique for obtaining a stable triboelectric charging property has been proposed, and many charging aids have been developed even today.

Furthermore, various methods have been devised as a method of adding the charging auxiliary agent as described above. For example, a method of adhering the toner particles to the surface of the toner particles by an electrostatic force between the toner particles and the charging aid, a Van der Waals force, or the like is common, and stirring, a mixer, or the like is used. However, in this method, it is not easy to uniformly disperse the additive on the surface of the toner particles, and the additives are not attached to the toner particles and the additives become aggregates, so that the existence of the additive in a so-called free state is not detected. It is difficult to avoid. This tendency becomes more remarkable as the specific electric resistance of the charging aid increases and the particle size decreases. In such a case, the performance of the toner is affected. For example, the amount of triboelectricity becomes unstable, the image density is not constant, and the image has a lot of fog.

Alternatively, when continuous copying or the like is carried out, the content of the charging aid changes, and the initial image quality cannot be maintained, which is a drawback.

As another addition method, there is a method of previously adding a charging auxiliary together with the binder resin and the colorant at the time of manufacturing the toner. However, it is not easy to make the charge control agent uniform, and what substantially contributes to the charging property is near the surface of the toner particles, and the charging auxiliary agent and the charge control agent present inside the particles have a charging property. Therefore, it is not easy to control the addition amount of the charging aid and the dispersion amount on the surface. Further, even in the toner obtained by such a method, the triboelectric charge amount of the toner is unstable and it is not possible to easily obtain a toner that satisfies the developer characteristics as described above. The reality is that we have not obtained sufficiently satisfactory quality.

Further, in recent years, demands for high definition and high image quality of copying machines have been increasing in the market, and in this technical field, an attempt has been made to achieve high image quality color by making toner particle size fine. However, as the particle size becomes finer, the surface area per unit weight increases, and the amount of electrification of the toner tends to increase, which may result in low image density and deterioration in durability. In addition, since the amount of electrification of the toner is large, the adhesive force between the toners is strong, the fluidity is lowered, and problems arise in the stability of toner replenishment and in imparting tribo to the replenishment toner.

Further, since the color toner does not contain a magnetic substance or a conductive substance such as carbon black, there is no portion for leaking charge, and the amount of charge generally tends to be large. This tendency is more remarkable when a polyester binder having high charging performance is used.

Further, particularly in color toners, the following characteristics are strongly desired. (1) It is necessary that the fixed toner is in a state of almost completely melted so that the shape of the toner particles cannot be discriminated so as not to diffusely reflect light and prevent color reproduction. (2) It must be a colored toner having transparency that does not interfere with the toner layers of different tones below the toner layer. (3) Each of the constituent toners must have well-balanced hue and spectral reflection characteristics and sufficient saturation.

From this viewpoint, many binder resins have been studied, but a toner satisfying all the above characteristics has not been developed yet. Today, polyester resins are often used as binder resins for color in the technical field, but toners made of polyester resins are generally susceptible to temperature and humidity, and have excessive charge amount under high humidity and high humidity. There is an urgent need to develop a color toner having a stable charge amount even in a wide range of environments due to the problem that the charge amount is insufficient.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrostatic charge developing toner which solves the above problems.

That is, an object of the present invention is to provide an electrostatic charge developing toner which is not easily affected by environment such as temperature and humidity, exhibits good fluidity, and always has stable triboelectric chargeability.

A further object of the present invention is to provide a toner for electrostatic charge development which has clear image characteristics free from fog and is excellent in durability stability.

[0026]

According to the present invention, after the surface treatment with silicone oil or silicone varnish in an aqueous system, the following general formula (I) is used.

[0027]

[Chemical 2] (In the formula, n is an integer of 4 to 12 and m is an integer of 1 to 3.) Contains titanium oxide treated by hydrolysis in a water system with a coupling agent and has a weight average particle diameter of 5 ~ 1
The toner is characterized by having a thickness of 0 μm.

As an example of toner containing hydrophobized titanium oxide, a toner containing titanium oxide treated with alkyltrialkoxysilane has been proposed in JP-A-59-52255. Although the electrophotographic properties are certainly improved by the addition of T.O., the surface activity of titanium oxide is originally small and coalesced particles are generated at the processing stage, and the hydrophobicity is non-uniform, so it is applied to full-color toners. I was not always satisfied.

The inventors of the present invention have earnestly studied the stabilization of the charging property of the toner. As a result, after treating a specific silicone oil or silicone varnish in an aqueous system, the specific coupling agent is hydrolyzed in the aqueous system. It was found that the treated titanium oxide having an average particle diameter of 0.01 to 0.2 μm and a degree of hydrophobicity of 40 to 80% can be subjected to a uniform hydrophobic treatment and there is no coalescence of particles, and the titanium oxide is contained. It was found that the above toner is extremely effective in stabilizing charge and imparting fluidity.

The purpose of this was to seal the functional group of titanium oxide remaining after the treatment with silicone oil or silicone varnish with a coupling agent. Surprisingly, the reactivity was once Or it was found to be very high because it was treated with silicon varnish. The reason for this is not clear yet, but since the organic treatment is performed in advance, the compatibility between the site other than the reactive group of the coupling agent and the lipophilic site on the titanium oxide surface is good, and the reaction efficiency is improved. It is presumed that it is because it is done.

Therefore, in the present invention, the coupling agent can be selected in a very wide range from low viscosity to high viscosity, and it is very effective in imparting chargeability and fluidity.

The coupling agent according to the present invention has n in the above formula (I) of 3 to 12, preferably 4 to.
10 is good, m is 1-3, preferably 1-2.

Here, n in the general formula of the coupling agent
Is less than 3, the treatment is easy but the hydrophobicity cannot be sufficiently achieved. Further, when n is larger than 12, the hydrophobicity is sufficient, but the titanium oxide particles are often coalesced with each other and the fluidity-imparting ability is deteriorated.

If m is larger than 3, the reactivity is lowered and the hydrophobic property is not sufficiently achieved.

The amount of silicon oil or silicon varnish to be treated is 0.1 to 1 with respect to 100 parts by weight of titanium oxide.
0 parts by weight, preferably 1 to 7 parts by weight, and the treatment amount of the coupling agent is 5 to 100 parts by weight of titanium oxide.
30 parts by weight, and the degree of hydrophobicity may be 40 to 80%, preferably 50 to 80%.

That is, if the degree of hydrophobicity is less than 40%, the amount of charge is greatly reduced by leaving it in a high humidity for a long period of time, a mechanism for promoting charge on the hardware side is required, and the apparatus becomes complicated. If the degree of conversion exceeds 80%, it becomes difficult to control the charge of titanium oxide itself, and as a result, the toner is charged up under low humidity.

Further, the particle size is 0.
01 to 0.2 μm is preferable. If the particle size is larger than 0.2 μm, toner charging becomes non-uniform due to poor fluidity, resulting in toner scattering and fog. Also, 0.0
If it is less than 1 μm, the toner is likely to be embedded on the toner surface, and the toner is deteriorated quickly and the durability is deteriorated. This tendency is more remarkable in the sharp melt color toner used in the present invention.

In the present invention, the titanium oxide is treated by treating it with silicon oil or silicon varnish while mechanically dispersing the titanium oxide in an aqueous system so as to have a primary particle size, and further hydrolyzing the coupling agent. The method of treatment is effective and preferable in that no solvent is used.

The silicone oil used in the present invention is not particularly limited, but the general formula

[0040]

[Chemical 3] (R ₁ and R ₂ are CH ₃ or OH), a dimethylpolysiloxane type represented by the general formula

[0041]

[Chemical 4] Methylhydrogenpolysiloxane type represented by, general formula

[0042]

[Chemical 5] A methylphenylpolysiloxane type represented by and the like can be used. Further, if necessary, alkyl modification,
Amino modification, epoxy modification, epoxy polyether modification, carboxyl modification, mercapto modification, alcohol modification, fluorine modification and the like may be performed.

The silicone oil preferably has a viscosity at 25 ° C. of 50 to 1000 centistokes. If it is less than 50 centistokes, the volatile content is large and the treatment effect does not last long.

On the other hand, if it exceeds 1000 centistokes, uniform treatment becomes difficult in a water system, resulting in extremely poor treatment efficiency.

The silicon varnish used in the present invention is also 2
It does not matter if the viscosity at 5 ° C. is 50 to 1000 centistokes.

Further, in the present invention, the treated titanium oxide has a light transmittance of 40% at a light length of 400 nm when dispersed in an ethanol solvent at a solid content concentration of 0.1%.
The above is also one of the features.

That is, when the titanium oxide of the present invention is used as a full-color toner, if the transparency to visible light is poor, the projected image of the OHP will be shaded and a clear toner will not be obtained.

The transmittance of the present invention was measured by UV2200 manufactured by Shimadzu Corporation.

The toner has a weight average particle diameter of 5 to 10 μm.
Even when the particle size is reduced, the titanium oxide of the present invention is suitable. When the particle size of the toner is reduced, the surface area per weight is increased, and excessive charging due to rubbing tends to occur. On the other hand, titanium oxide fine particles that can control charge and impart fluidity have a great effect.

A charge control agent may be added to the toner according to the present invention in order to stabilize the charge characteristics. At that time, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferable. Examples of the negative charge control agent at that time include organic metal complexes such as metal complexes of alkyl-substituted salicylic acid (for example, chromium complex or zinc complex of di-tert-butylsalicylic acid). When the negative charge control agent is blended in the toner, it is 0.1-12 per 100 parts by weight of the binder resin.
It is good to add 0.5 part by weight, preferably 0.5 to 8 parts by weight.

When a two-component developer is prepared by mixing with the toner according to the present invention, the mixing ratio is usually 2 to 10% by weight, preferably 3 to 9% by weight as the toner concentration in the developer. Results are obtained. If the toner concentration is less than 2% by weight, the image density is too low to be practical, and 10% by weight
If it exceeds, the fog and the scattering in the machine are increased, and the useful life of the developer is shortened.

As the colorant used in the present invention, known dyes and pigments such as phthalocyanine blue, indanthrene blue, peacock blue, permanent red, lake red, rhodamine lake, hansa yellow, permanent yellow, benzidine yellow and the like are widely used. can do. The content thereof is 12 parts by weight or less, and preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin so as to sensitively reflect the transparency of the OHP film.

If necessary, the toner of the present invention may be mixed with additives within a range that does not impair the properties of the toner. Examples of such additives include Teflon, zinc stearate and polyvinylidene fluoride. Such lubricants, fixing aids (for example, low molecular weight polyethylene, low molecular weight polypropylene, etc.), organic resin particles and the like can be used.

In the production of the toner of the present invention, the constituent materials are well kneaded by a heat kneader such as a hot roll, a kneader, an extruder or the like, and then mechanical pulverization and classification are carried out, or in a binder resin solution. After dispersing a material such as a colorant in, a method obtained by spray drying, or
After mixing the predetermined material to the monomer that should constitute the binder resin,
Each method such as a method for producing a polymerized toner in which a toner is obtained by polymerizing this emulsion suspension can be applied.

As the binder substance used in the colorant-containing resin particles of the present invention, various material resins conventionally known as electrophotographic toner binder resins are used.

For example, polystyrene, styrene-based copolymers such as styrene-butadiene copolymer, styrene-acrylic copolymer, etc., ethylene-based such as polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer. Examples thereof include copolymers, phenolic resins, epoxy resins, acrylic phthalate resins, polyamide resins, polyester resins, maleic acid resins and the like. In addition, the manufacturing method and the like of each resin is not particularly limited.

Among these resins, the effect of the present invention is great when a polyester resin having a high negative chargeability is used. That is, while the polyester-based resin has excellent fixability and is suitable for color toners, it has a strong negative charging ability and tends to be excessively charged, but when the polyester resin is used in the constitution of the present invention, adverse effects are improved and excellent. Toner is obtained.

In particular, the following equation

[0059]

[Chemical 6] (In the formula, R is an ethylene or propylene group, and x, y
Are each an integer of 1 or more, and the average value of x + y is 2 to 10. ), A bisphenol derivative or a substitution product represented by the formula (1) is used as a diol component, and a carboxylic acid component comprising a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, phthalate). Acid, terephthalic acid, trimellitic acid, pyromellitic acid and the like) are more preferable because they have a sharp melting property.

When the toner of the present invention is used to prepare a two-component developer using a carrier, an electrically insulating resin is used as a coating resin for the surface of the carrier, which is appropriately selected depending on the toner material and carrier core material. .. In the present invention, at least one monomer selected from at least acrylic acid (or its ester) monomer and methacrylic acid (or its ester) monomer in order to improve the adhesion to the surface of the carrier core material. It is necessary to contain.
In particular, when polyester resin particles having a high negative chargeability are used as the toner material, it is preferable to use a copolymer with a styrene-based monomer for the purpose of stabilizing the charge. Is preferably 5 to 70% by weight.

As the monomer for the resin for coating the carrier core material which can be used in the present invention, as the styrene-based monomer,
For example, styrene monomer, chlorostyrene monomer, α
-Methylstyrene monomer, styrene-chlorostyrene monomer and the like, and examples of acrylic monomers include acrylic acid ester monomers (methyl acrylate monomer, ethyl acrylate monomer, butyl acrylate monomer, octyl acrylate monomer, phenyl acrylate monomer). , Acrylic acid 2 ethylhexyl monomer) and the like, and methacrylic acid ester monomers (methyl methacrylate monomer, ethyl methacrylate monomer, butyl methacrylate monomer, phenyl methacrylate monomer) and the like.

The carrier core material (magnetic particles) used in the present invention includes, for example, surface-oxidized or unoxidized metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earths, and alloys or oxides thereof. Things can be used.
Moreover, there is no particular limitation in the manufacturing method.

Next, an example of an image forming apparatus for performing non-magnetic one-component development using the toner of the present invention will be described, but the present invention is not necessarily limited to this. In Figure 1,
1 shows an apparatus for developing an electrostatic image formed on a latent image carrier. Reference numeral 1 denotes a latent image holder, which is formed by an electrophotographic process means or an electrostatic recording means (not shown). Two
Is a developer carrying member and is composed of a non-magnetic sleeve made of aluminum or stainless steel. The non-magnetic one-component color toner is stored in the hopper 3 and is supplied onto the developer carrier by the supply roller 4. The supply roller 4 also removes the toner on the developer carrying member after development. The toner supplied onto the developer carrier is uniformly and thinly applied by the developer applying blade 5.
The contact pressure between the developer coating blade and the developer carrying member is effectively 3 to 250 g / cm, preferably 10 to 120 g / cm as the linear pressure in the sleeve generatrix direction. When the contact pressure is less than 3 g / cm, it becomes difficult to apply the toner uniformly, and the distribution of the charge amount of the toner becomes broad, causing fog and scattering. If the contact pressure exceeds 250 g / cm, a large pressure is applied to the toner, and the toner particles are aggregated or crushed, which is not preferable. By adjusting the contact pressure to 3 to 250 g / cm, it becomes possible to loosen the agglomeration peculiar to the toner having a small particle diameter, and it is possible to instantly raise the charge amount of the toner. As the developer coating blade, it is preferable to use a triboelectric charging series material suitable for charging the toner to a desired polarity.

In the present invention, silicone rubber, urethane rubber, styrene-butadiene rubber and the like are preferable. Further, it may be coated with a polyamide resin or the like. Further, it is preferable to use a conductive rubber or the like because it is possible to prevent the toner from being excessively charged.

In the system proposed by the present invention for coating a thin layer of toner on a developer carrying member with a blade, the thickness of the toner layer on the developer carrying member is adjusted to obtain a sufficient image density. It is necessary to make it smaller than the facing gap length between the developer carrying member and the latent image holding member, and apply an alternating electric field to this gap. That is, the bias power source 6 shown in FIG. 1 applies an alternating electric field or a developing bias in which a direct current electric field is superimposed on the alternating electric field between the developer carrying member and the latent image holding member, thereby holding the latent image holding member from the developer carrying member. It is possible to facilitate the movement of the toner onto the body and obtain a high quality image.

The measuring method of the present invention will be described below. (1) Toner particle size measurement: The particle size distribution can be measured by various methods, but in the present invention, it was measured using a Coulter counter.

That is, a Coulter counter TA-II type (manufactured by Coulter) is used as a measuring device, and an interface (manufactured by Nikkaki) for outputting number average distribution and volume distribution and a CX-1 personal computer (manufactured by Canon) are connected. Then, the electrolyte is 1
% NaCl aqueous solution is prepared. As a measuring method, a surfactant, preferably an alkylbenzene sulfonate, as a dispersant is added to 100 to 150 ml of the electrolytic aqueous solution in an amount of 0.1.
Add ~ 5 ml, and then add 2 to 20 mg of the measurement sample.
The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the Coulter Counter TA-II type was used to measure the volume and number of toners using a 100 μm aperture as an aperture. The volume distribution and number distribution of ˜40 μm were calculated. Then, according to the present invention, the weight-based weight average diameter (D
4) (The median value of each channel is set as a representative value for each channel), the weight-based coarse powder amount obtained from the volume distribution (1
6.0 μm or more), and the number-based fine powder number (5.04 μm or less) determined from the number distribution was determined. (2) Hydrophobicity measurement: The methanol titration test is an experimental test for confirming the hydrophobicity of titanium oxide fine powder having a hydrophobized surface.

The "methanol titration test" defined in this specification for evaluating the hydrophobicity of the treated titanium oxide fine powder is performed as follows. Titanium oxide fine powder 0.2 g was placed in an Erlenmeyer flask with a volume of 250 ml and water 50 m.
Add to l. Methanol is titrated from the burette until the total amount of titanium oxide is wet. At this time, the solution in the flask is constantly stirred with a magnetic stirrer. The end point is observed by suspending the total amount of fine titanium oxide powder in the liquid and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.

The present invention will be described in detail below with reference to examples.

[0070]

【Example】

(Production Example 1 of titanium oxide) Hydrophilic titanium oxide fine particles (particle size: 0.05 μm, BET120 m ² / g) are mixed and stirred in an aqueous system, and dimethylpolysiloxane having a viscosity of 500 centistokes at 25 ° C. is used as a treatment agent. Was dispersed in a water system to form an emulsion, and the mixture was added and mixed so that the particles did not coalesce so as to be 5% of the titanium oxide fine particles in terms of solid content, then dried and crushed to obtain a hydrophobicity of 30.
%, The average particle size was 0.05 μm, and the titanium oxide fine particles a had a transmittance at 400 nm of 50%.

(Production Example 2 of titanium oxide) Titanium oxide a
And the mixture was stirred in _{water, n-C 8 H 17 -Si-} (OCH
₃ ) Dispersion of ₃ in an aqueous solution to form an emulsion is added to and mixed with titanium oxide fine particles so that the solid content is 20% by weight so that the particles do not coalesce, and the mixture is dried and crushed. , Hydrophobicity 70%, average particle size 0.05 μm, 40
Titanium oxide b having a transmittance of 55% at 0 nm was obtained.

(Production Examples 3 and 4 of Titanium Oxide) In Production Example 2, n-C ₆ H ₁₃ -Si- was used as the coupling agent.
_{(OCH 3) 3, n-} C 10 H 21 -Si- (OCH 3) 3
And a hydrophobicity of 60% and an average particle size of 0.
Titanium oxide c having a transmittance of 60% at 05 μm and 400 nm, a hydrophobicity of 70% and an average particle size of 0.05 μ
Titanium oxide d having a transmittance of 50% at m and 400 nm was obtained.

Production Example 5 of Titanium Oxide In the same manner as in Production Example 1, except that 25% by weight of dimethylpolysiloxane was used, the degree of hydrophobicity was 55% and the average particle size was 0.05 μm.
Titanium oxide e having a transmittance of 40% at m and 400 nm was obtained.

Production Example 6 of Titanium Oxide Production Example 2 except that the hydrophilic titanium oxide of Production Example 1 is further sintered at high temperature.
In the same manner as above, hydrophobicity 80%, average particle size 0.3 μm,
Titanium oxide f having a transmittance of 5% at 400 nm was obtained.

(Production Example 7 of Titanium Oxide) Oxidation with a hydrophobicity of 45%, an average particle size of 0.05 μm and a transmittance of 60% at 400 nm was performed in the same manner as in Production Example 2 except that the treating agent was 10% by weight. Titanium g was obtained.

Example 1 Polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid Phthalocyanine pigment 4 parts 4 parts of chromium complex salt of di-tert-butylsalicylic acid 4 parts were sufficiently premixed by a Henschel mixer and 3 parts The mixture was melted and kneaded at least twice with a roll mill, cooled, coarsely pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized with a fine pulverizer by an air jet system. Further, the finely pulverized product obtained was classified to select 2 to 10 μm so as to obtain the particle size distribution of the present invention, to obtain colorant-containing resin particles.

Cyan toner was prepared by mixing 1.0% of titanium oxide b with a Henschel mixer. This cyan toner had a weight average diameter of 8.2 μm.

To 5 parts of this toner, a copolymer (weight average molecular weight 200,000) of 75% methyl methacrylate and 25% butyl acrylate was added, and the weight average particle diameter was 45 μm.
m, 35 μm or less 4.2%, 35-40 μm 9.5%,
Cu-Zn- having a particle size distribution of 74 μm or more and 0.2%
A carrier obtained by coating an Fe-based ferrite carrier with 0.5% was mixed so as to make a total amount of 100 parts to obtain a developer.

Using this developer, a commercially available plain paper color copying machine (color laser copier 500, manufactured by Canon) was used to set the development contrast to 300 V, and the temperature was 23 ° C./65%.
Images were drawn below. The image obtained is Macbeth RD9
The reflection density was measured using an 18-inch SPI filter (the same applies to the subsequent image density measuring method). The image density was as high as 1.51 and was clear without any fog. Also, the OHP projected image was clear and had no dust. After that, 10,000 more copies were made, but the density fluctuation during that time was as small as 0.08, and the fog and sharpness were the same as in the initial stage. Under low temperature and low humidity (20 ℃,
Even at 10% RH), when the development contrast was set to 300 V and image formation was performed, the image density was as high as 1.46, suggesting that the present invention was effective in controlling the charge amount under low humidity. ing.

Further, even under high temperature and high humidity (30 ° C./80%)
Similarly, when the development contrast was set to 300 V and image formation was performed, the image density was 1.55, and a very stable and good image was obtained.

23 ° C./60% RH, 20 ° C./10
%, 30 ° C./80%, the initial image after being left for 1 month in each environment showed no abnormality.

Example 2 The same procedure as in Example 1 was carried out except that titanium oxide c was used instead of titanium oxide b in Example 1, and the temperature was 30 ° C./8.
Under 0%, the image density was slightly high at 1.54 to 1.61, but good results were obtained.

Example 3 The same procedure as in Example 1 was carried out except that titanium oxide d was used instead of titanium oxide b in Example 1, and the temperature was 20 ° C./1.
At 0%, the image density was slightly low at 1.40 to 1.46, but good results were obtained.

Comparative Example 1 The procedure of Example 1 was repeated except that titanium oxide a was used in place of titanium oxide b of Example 1, and the temperature was 30 ° C./8.
At 0%, the image density was as high as 1.70 and some fog was observed.

Comparative Example 2 The procedure of Example 1 was repeated except that titanium oxide e was used in place of titanium oxide b of Example 1, and the temperature was 30 ° C. /
When left under 80% for 1 month, the image density increased to 1.75, and fog and toner scattering were slightly observed.

Comparative Example 3 The same procedure as in Example 1 was carried out except that titanium oxide f was used in place of titanium oxide b in Example 1. As a result, the fluidity was lowered, the image quality was lowered, and the OHP projection image was obtained. The sharpness of the image deteriorated.

Example 4 The same as in Example 1 except that the developing device of a commercially available color copying machine (color laser copier 500, manufactured by Canon) was modified as shown in FIG. When images were printed, the image density was 1.47 to 1.51 at 20 ° C./10%, 1.50 to 1.53 at 23 ° C./65%, and 1.50 at 30 ° C./80%. Good results of ~ 1.57 were obtained.

Example 5 The same procedure as in Example 1 was carried out except that titanium oxide g was used, and the image density was 1.56 to 1% at 30 ° C./80%.
Although it was as high as 65, good results were obtained.

[0089]

INDUSTRIAL APPLICABILITY According to the present invention, by improving oxide fine particles, particularly by using titanium oxide treated with a coupling agent having a specific structure, it is possible to stabilize the charge in various environments and to improve the charge stability. It shows fluidity and achieves high image quality.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a developing device.

[Explanation of symbols]

 1 latent image carrier 2 developer carrier 3 hopper 4 supply roller 5 developer coating blade 6 power supply

Claims (3)

[Claims] 1. After being surface-treated with silicone oil or silicone varnish in an aqueous system, the following general formula (I): (In the formula, n is an integer of 3 to 12, and m is an integer of 1 to 3.) Contains titanium oxide treated with hydrolysis in a water system with a coupling agent, and has a weight average particle diameter of 5 ~ 1
A toner having a thickness of 0 μm. 2. The processing amount of the silicon oil or the silicon varnish is 0.
The toner according to claim 1, wherein the amount of the coupling agent is 1 to 10 parts by weight, and the amount of the coupling agent treated is 5 to 30 parts by weight based on 100 parts by weight of titanium oxide. 3. The titanium oxide has an average particle size of 0.01 to
The toner according to claim 1 or 2, wherein the toner has a hydrophobicity of 0.2 μm, a hydrophobicity of 40 to 80%, and a light transmittance of 400% or more at 400 μm.