JPH0611887A - Toner - Google Patents

Abstract

PURPOSE:To attain stable triboelectricity without being influenced by environment by using a toner containing titanium oxide and having a specific weight average particle diameter and reprocessing the titanium oxide in an organic solvent after surface processing with a silicone oil or silicone vanish. CONSTITUTION:The toner contains the titanium oxide and has 5-10mum weight average particle diameter and the titanium oxide is reprocessed in the organic solvent after being processed with the silicone oil or silicone vanish in water base. That is, the titanium oxide is processed with the specific silicone oil or silicone vanish in water base and is reprocessed in the organic solvent capable of dissolving the silicone oil or silicone vanish to uniformly make the titanium oxide having 0.02-0.3mum average particle diameter hydrophobic so as to have high hydrophobicity of 40-80%. Thus, the toner containing the titanium oxide free from unifying particles with each other has excellent properties in the stability of charge and in fluidity.

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]

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.
Many methods are known, such as Japanese Patent No. 4748, but generally, a photoconductive substance is 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 an extremely 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. In addition, 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 by 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 specification, 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 has been often adopted 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 has been rapidly progressing in copying machines and the like, and two-color copying machines and full-color copying machines have been studied and put to practical use. For example, "Electronic Photography 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 television, a photograph, and 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. Images are not always pleasing.

Color image formation by full-color electrophotography generally reproduces all colors using color toners of three primary colors of 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. Hold on a support. This step is sequentially carried out a plurality of times, the toners are superposed on the same support while matching the registration, and then the final full-color image is obtained by fixing once.

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. 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 problems, the search for carrier core agents and carrier coating agents and the optimization of the coating amount, the examination of charge control agents and fluidity imparting agents to be added to toners, and the binder serving as the base material are taken place. Many studies have been made to achieve excellent triboelectrification properties in all materials constituting a 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 auxiliary agent, 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 particle, and the additive does not adhere to the toner particle and the additives become aggregates, so that the existence of the additive in a so-called free state is present. 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 in which a charging auxiliary agent is added in advance 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 it is the toner near the surface of the toner particles that substantially contributes to the chargeability, and the charge auxiliary agent and charge control agent present inside the particles have the chargeability 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 the quality is not sufficiently satisfactory.

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 reducing the particle size of toner. However, when the particle size becomes finer, the surface area per unit weight increases, and the amount of electrification of the toner tends to increase, and there is a concern that the image density is low and the durability is deteriorated. In addition, since the amount of electrification of the toner is large, the adhesion between the toners is strong, the fluidity is lowered, and problems occur in stability of toner replenishment and tribo application 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 increase. 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) The fixed toner needs to be 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 widely used as color binder resins 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.

On the other hand, one of the means for solving these problems is to add various chemical substances to the toner.

In particular, for the purpose of improving various image characteristics such as resolution, density uniformity, and fog, various fine powders are widely added to improve the chargeability and fluidity of the toner. Has been done.

Titanium oxide fine particles are mentioned as one of the fine powders generally used as fine powders added to improve the various properties of the toner. Particularly, those fine particles surface-treated with silicon oil or silicon varnish are highly hydrophobic. It has a degree of chemical conversion and is more preferably used.

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 addition of various electrophotographic properties has certainly improved, the surface activity of titanium oxide is originally small and coalesced particles are generated at the treatment stage, and the hydrophobicity is not uniform or insufficient. It was not satisfactory when applied to full color toners.

[0027]

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

That is, an object of the present invention is to provide a toner for electrostatic charge development which is not easily influenced by environment such as temperature and humidity and which always has stable triboelectric charging property.

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 has excellent durability stability.

[0030]

The present invention relates to a toner containing titanium oxide and having a weight average particle size of 5 to 10 μm, after the titanium oxide is treated with silicone oil or silicone varnish in an aqueous system. The toner is reprocessed in an organic solvent.

Further, the present invention is a toner characterized in that the above-mentioned reprocessing is carried out in an organic solvent containing silicone oil or silicone varnish.

As a method for producing titanium oxide fine particles, there are a dry method produced by oxidizing titanium tetrachloride or alkoxy titanium in a gas phase and a wet method produced by hydrolyzing titanium tetrachloride in an aqueous solution.

In the dry method using titanium tetrachloride, toxic chlorine gas is generated during the reaction, and a large-scale manufacturing apparatus and a complicated manufacturing process are required to recover this gas, and temperature control at high temperature is required. It has the difficulty of being difficult. Further, when alkoxy titanium is used, not only the raw material is very expensive, but also the temperature control is more strict, which is disadvantageous in terms of cost.

On the other hand, in the wet method, even if titanium tetrachloride or the like is used, no toxic by-product is generated. Therefore, the wet method using titanium tetrachloride as a raw material is safe, has a simple manufacturing process, and is low in material cost. It is preferable in terms. However, when the wet titanium oxide thus obtained is taken out of the aqueous system as it is, coalesced particles are generated due to secondary agglomeration and the like, and it cannot be obtained as a uniform fine powder after drying. I can't get it. Therefore, for the purpose of preventing coalescence and further increasing the hydrophobicity, it is preferable to treat with a specific silicone oil or silicone varnish in an aqueous system.
However, it is true that such treatment prevents the particles from coalescing, and titanium oxide fine particles having a certain degree of hydrophobicity can be obtained. However, in an aqueous system, the silicone oil or silicon varnish, which is originally hydrophobic, makes it hydrophilic. It is difficult to uniformly treat titanium oxide, which is a property, and even if this titanium oxide is added to a toner, it is not always satisfactory when it is applied to full color.

The inventors of the present invention have made extensive studies as to stabilization of the chargeability of the toner. The average particle size of 0.02 to 0.3 μm
It was found that titanium oxide, which has a very high hydrophobicity of 40 to 80%, can be subjected to a uniform hydrophobic treatment and that particles do not coalesce, and the toner containing the titanium oxide stabilizes charging and imparts fluidity. It was found that they have extremely excellent characteristics in terms of.

Here, the amount of silicon oil or silicon varnish to be treated is 100
0.1-40 parts by weight, preferably 1-3
0 parts by weight is preferable. In the reprocessing in an organic solvent, the degree of hydrophobicity is 40 to 80%, preferably 60 to
It should be 80%. That is, when the degree of hydrophobicity is less than 40%, the amount of charge is greatly reduced by leaving it in high humidity for a long period of time, a mechanism for promoting charge on the hardware side is required, and the apparatus becomes complicated, and the degree of hydrophobicity is 80%. If it exceeds, it becomes difficult to control the charge of titanium oxide itself, and as a result, the toner is charged up in low humidity.

Further, the particle size thereof is 0.
02-0.3 μm is preferable. When the particle size is larger than 0.3 μm, toner charging becomes non-uniform due to poor fluidity, resulting in toner scattering and fog. Also, 0.0
If it is smaller than 2 μm, the toner is likely to be embedded on the toner surface, and the toner is deteriorated quickly and the durability is decreased. This tendency is more remarkable in the sharp melt color toner used in the present invention.

In the present invention, the method for treating titanium oxide is obtained by treating titanium oxide with silicon oil or silicon varnish while mechanically dispersing the titanium oxide in an aqueous system so as to have a primary particle size, then filtering and drying. The method of retreating the titanium oxide fine particles in an organic solvent is effective, and titanium oxide fine particles having a high degree of hydrophobicity can be obtained.

When reprocessing in an organic solvent, silicon oil or silicon varnish may be further added as the second silicon oil or silicon varnish. The second silicone oil or silicone varnish may be different from the first silicone oil or silicone oil used for the treatment in the aqueous system. When different combinations are used, the obtained titanium oxide is uniformly treated with two or more kinds of silicon oil or silicon varnish, and it is possible to have a plurality of functions, which is preferable.

When silicone oil or silicone varnish is used for both treatment in an aqueous system and treatment in an organic solvent,
The treatment amount of both the former and the latter is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of titanium oxide.

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

[0042]

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

[0043]

[Chemical 2] 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, and the treatment efficiency is extremely deteriorated.

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, the effect of titanium oxide fine particles that can control charge and impart fluidity is great.

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 pale color 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 0.1-10 with respect to 100 parts by weight of the binder resin.
It is preferable to add 0.5 part by weight, preferably 0.5 to 8 parts by weight.

When a toner according to the present invention and a carrier are mixed to prepare a two-component developer, the mixing ratio thereof is 2 to 12% by weight, preferably 3 to 12% by weight as the toner concentration in the developer.
Good results are usually obtained with 9% by weight. If the toner density is 2% by weight or less, the image density is low and it becomes unpractical.
If it exceeds 10% by weight, fog and in-flight scattering will increase.
Shortens the useful life of the developer.

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, 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 characteristics 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, a method in which the constituent materials are well kneaded by a heat kneader such as a hot roll, a kneader or an extruder and then mechanically pulverized or classified, 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, phenol 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 are not particularly limited.

Among these resins, the effect of the present invention is remarkable when a polyester resin having a high negative chargeability is used. That is, while polyester-based resins have excellent fixability and are suitable for color toners, they have a strong negative charging ability and are prone to excessive charging, but when the polyester resin is used in the constitution of the present invention, the harmful effects are improved and excellent. Toner is obtained.

In particular, the following equation

[0059]

[Chemical 3] (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 composed of a carboxylic acid having a valence of 2 or more or an acid anhydride thereof or a lower alkyl ester thereof (eg, fumaric acid, maleic acid, maleic anhydride, phthalate). An acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) is more preferable because it has 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 the 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, stainless steel or the like. The non-magnetic one-component color toner is stored in the hopper 3 and is supplied by the supply roller 4 onto the developer carrying member. 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 toner charge amount distribution becomes broad, which causes 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 in an amount of 0.1 to 100 ml in the electrolytic aqueous solution of 100 to 150 ml.
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), and the weight-based coarse powder amount (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 carried out as follows. Titanium oxide fine powder 0.2 g was placed in a 250 ml Erlenmeyer flask with 50 m of water.
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 hydrophobization is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.

[0071]

EXAMPLES The present invention will be described in detail below with reference to examples. % Means% by weight and part means part by weight.

Production Example 1 of Titanium Oxide Hydrophilic titanium oxide fine particles produced in an aqueous system are mixed and stirred, and dimethylpolysiloxane having a viscosity of 500 centistokes at 25 ° C. is dispersed in the aqueous system as an treating agent to obtain an emulsion. Is the titanium oxide fine particles converted to solid content.
Add and mix so that the particles do not coalesce to 0%, dry dry and crush, and make hydrophobicity 35%, average particle size 0.05μ
Titanium oxide fine particles A having a transmittance of 50% at m and 400 nm were obtained.

(Production Example 2 of Titanium Oxide) Titanium oxide A was mixed in a xylene-based solvent, stirred so that the particles did not coalesce, dried and crushed to have a hydrophobicity of 60% and an average particle size of 0.05.
Titanium oxide B having a transmittance of 55% at μm and 400 nm
Got

Production Example 3 of Titanium Oxide In the same manner as in Production Example 1 except that 35% by weight of dimethylpolysiloxane was used, the degree of hydrophobicity was 55%, the average particle size was 0.05 μm, and 4
Titanium oxide C having a transmittance of 30% at 00 nm was obtained.

(Production Example 4 of Titanium Oxide) Titanium oxide C was mixed in a xylene-based solvent, stirred so that the particles did not coalesce, dried and crushed to have a hydrophobicity of 70% and an average particle size of 0.05.
Titanium oxide D with a transmittance of 50% at μm and 400 nm
Got

(Production Example 5 of Titanium Oxide) Hydrophilic titanium oxide fine particles formed in an aqueous system were dried and crushed under the condition without treatment with silicon oil or silicon varnish,
Then, it was treated with 10% of dimethylpolysiloxane used in Production Example 1 in a xylene solvent to obtain titanium oxide E having a hydrophobicity of 40%, an average particle diameter of 0.4 μm and a transmittance of 5% at 400 nm.

Production Example 6 of Titanium Oxide In the same manner as in Production Example 5, except that the amount of dimethylpolysiloxane was 35%, the degree of hydrophobicity was 70%, the average particle size was 0.4 μm, and the particle size was 400 μm.
Titanium oxide F having a transmittance of 10% in nm was obtained.

(Production Example 7 of Titanium Oxide) Titanium oxide A was mixed and stirred in a xylene-based solvent, and the treating agent obtained by dissolving the silicone oil used in Production Example 1 in the solvent was solid-typed with respect to titanium oxide fine particles. Add and mix so that the particles do not coalesce to 5%, and dry and disintegrate to make the degree of hydrophobicity 70
%, An average particle size of 0.08 μm, and a transmittance of 55% at 400 nm of titanium oxide G were obtained.

(Production Example 8 of Titanium Oxide) In Production Example 7, the silicone oil has a viscosity of 300 at 25 ° C.
Hydrophobicity 72%, average particle size 0.08 μm, 400 using 000 centistokes dimethylpolysiloxane
Titanium oxide H having a transmittance of 50% in nm was obtained.

Production Example 9 of Titanium Oxide In the same manner as in Production Example 7, except that 5% by weight of fluorine-modified silicone oil is used, the degree of hydrophobicity is 80%, the average particle size is 0.06 μm,
Titanium oxide I having a transmittance of 50% at 400 nm was obtained.

(Production Example 10 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 J having a transmittance of 40% at m and 400 nm was obtained.

(Production Example 11 of Titanium Oxide) Oxidation with a hydrophobicity of 75%, an average particle size of 0.15 μm, and a transmittance of 20% at 400 nm was performed in the same manner as in Production Example 7 except that 25% by weight of the treating agent was used. Titanium K 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 by an air jet type fine pulverizer. Further, the obtained finely pulverized product was classified and 2 to 10 μm was selected 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 Henschel mixer. This cyan toner had a weight average diameter of 8.2 μm.

Copolymer consisting of 75% methyl methacrylate and 25% butyl acrylate (weight average molecular weight 20
10,000), the weight average particle size of 45 μm, 4.2 μm for 35 μm or less
%, 35-40 μm is 9.5%, 74 μm or more is 0.2
% Of Cu--Zn--Fe ferrite carrier having a particle size distribution of 0.5% was prepared, and the coated carrier was mixed with 5 parts of the toner so that the total amount was 100 parts, and a developer was prepared. did.

Using this developer, the development contrast was set to 330 V in a commercially available plain paper color copying machine (color laser copier 500, made by Canon) and 23 ° C./60%.
Images were drawn below. The image obtained is Macbeth RD9
Reflection density measurement was performed using an 18-inch SPI filter (the same applies to subsequent image density measurement methods). This image density was as high as 1.50 and was clear without any fog. Also, the OHP projection image was clear and had no dust. After that, 10,000 more copies were carried out, but the density fluctuation during that time was as small as 0.08, and fog and sharpness similar to those at the initial stage were obtained. Under low temperature and low humidity (20 ℃,
Even at 10% RH), when the development contrast was set to 330 V and image formation was performed, the image density was as high as 1.45, suggesting that the present invention was effective in controlling the charge amount under low humidity. ing.

Even under high temperature and high humidity (30 ° C./80%)
Similarly, when the development contrast was set to 330 V and image formation was performed, the image density was 1.57, and a very stable and good image was obtained.

Further, 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 D was used instead of titanium oxide B in Example 1, and the result was 20 ° C. /
Under 10%, the image density was slightly low at 1.40 to 1.46, but good results were obtained.

Example 3 A commercially available color copying machine (color laser copier 500, manufactured by Canon) was modified as shown in FIG. 1 to prepare 3,000 sheets in the same manner as in Example 1 except that no carrier was used. When images were printed, the image density was 1.47 to 1.49 at 20 ° C / 20%, 1.50 to 1.54 at 23 ° C / 60%, and 1.52 at 30 ° C / 80%. A good result of 1.57 was obtained.

Comparative Example 1 The same procedure as in Example 1 was carried out except that titanium oxide A was used instead of titanium oxide B in Example 1, and the temperature was 30 ° C./8.
At 0%, the image density was as high as 1.74, and fog and toner scattering were slightly recognized as compared with Example 1. However, there was no problem on the actual image.

COMPARATIVE EXAMPLE 2 The procedure of Example 1 was repeated except that titanium oxide C was used instead of titanium oxide B of Example 1, and the temperature was 30 ° C. /
Under 80%, the image density increased to 1.75 from around 2,000 sheets of continuous copying, and some fog and toner scattering were recognized. Also, the OHP projection image was slightly less sharp.

Comparative Example 3 The same procedure as in Example 1 was carried out except that titanium oxide E was used instead 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.

Comparative Example 4 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, but the fluidity was lowered, the image quality was lowered, and the OHP projection image was clear. Became worse.

Example 4 1.0% of titanium oxide B in Example 1 was replaced with titanium oxide G1.
A developer was prepared in the same manner as in Example 1 except that 0% was used.

Using this developer, a commercially available plain paper color copying machine (color laser copier 500, manufactured by Canon Inc.) was used to set the development contrast to 330 V and 23 ° C./60%.
Images were drawn below. The image obtained is Macbeth RD9
Reflection density measurement was performed using an 18-inch SPI filter (the same applies to subsequent image density measurement methods). The image density was as high as 1.49 and was clear without any fog. Also, the OHP projection image was clear and had no dust. After that, 10,000 more copies were carried out, but the density fluctuation during that time was as small as 0.08, and fog and sharpness similar to those at the initial stage were obtained. Under low temperature and low humidity (20 ℃,
Even at 10% RH), when the development contrast was set to 330 V and image formation was performed, the image density was as high as 1.44, 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 330 V and image formation was performed, the image density was 1.56, 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 5 The same procedure as in Example 4 was carried out except that titanium oxide H was used instead of titanium oxide G in Example 4, and the temperature was 23 ° C. /
Even when 10,000 copies were made under 60%, the image density variation was almost 1.45 to 1.49, and good results without image deterioration were obtained.

Example 6 The same procedure as in Example 4 was carried out except that titanium oxide I was used instead of titanium oxide G in Example 4, and a toner having very good fluidity was obtained at 20 ° C. / Under 10%, the image density was slightly low at 1.38 to 1.44, but a very clear image was obtained.

Example 7 The same as in Example 4 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 1.49 at 20 ° C / 20%, 1.50 to 1.54 at 23 ° C / 60%, and 1.52 at 30 ° C / 80%. A good result of 1.57 was obtained.

Comparative Example 5 The procedure of Example 4 was repeated except that titanium oxide J was used in place of titanium oxide G of Example 4, and the temperature was 30 ° C./8.
Image density is 1. after about 2,000 continuous copies under 0%.
It was as high as 75, and some fog and toner scattering were recognized. Also, the OHP projection image was slightly less sharp.

Comparative Example 6 The same procedure as in Example 4 was carried out except that titanium oxide K was used in place of titanium oxide G in Example 4, and the fluidity was lowered, the image quality was lowered, and the OHP projection image was obtained. The sharpness of the image deteriorated.

[0104]

INDUSTRIAL APPLICABILITY According to the present invention, by improving the method for hydrophobizing fine oxide particles, in particular, by reprocessing oil in an organic solvent, various environments of the toner to which this treated titanium oxide is added are added. It was possible to stabilize the charging in the above, and to show good fluidity, and to achieve 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 (5)

[Claims] 1. A weight average particle diameter of 5 to 5 containing titanium oxide.
A toner having a particle size of 10 μm, wherein titanium oxide is one which has been treated with silicone oil or silicone varnish in an aqueous system and then retreated in an organic solvent. 2. The toner according to claim 1, wherein the treatment amount of the silicone oil or silicone varnish in the aqueous system is 0.1 to 40 parts by weight with respect to 100 parts by weight of titanium oxide. 3. The toner according to claim 1, wherein the reprocessing is performed in an organic solvent containing silicone oil or silicone varnish. 4. The treatment amount of silicon oil or silicon varnish in the aqueous system is 0.1 to 20 parts by weight with respect to 100 parts by weight of titanium oxide, and the amount of silicon oil or silicon varnish in the organic solvent is The toner according to claim 3, wherein the treatment amount is 0.1 to 20 parts by weight with respect to 100 parts by weight of titanium oxide. 5. The titanium oxide has an average particle diameter of 0.02 to 0.02.
0.3 μm, the degree of hydrophobicity is 40 to 80%, and the light transmittance at 40 nm is 40% or more.
4. The toner according to any one of 4 above.