JP3198367B2 - toner - Google Patents

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 image in electrostatic printing or the like.

[0002]

2. Description of the Related Art It is well known in the art to form and develop an image on the surface of a photoconductive material by electrostatic means.

That is, US Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-2
A number of methods are known, such as Japanese Patent No. 4748, but generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the toner is called a toner on the latent image. A toner image corresponding to an electrostatic latent image is formed by attaching an extremely finely pulverized inspection material.

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

[0005] A developing method for visualizing an electric latent image by using a toner is described in, for example, a powder cloud method described in US Pat. No. 2,221,776, and US Pat. No. 2,618,55.
No. 2,874,063, a magnetic brush method, and a conductive property described in 3,909,258. A method using a magnetic toner is known.

As a toner applied to these developing methods, a toner obtained by mixing and dispersing a colorant in a thermoplastic resin and then pulverizing the same is used. As the thermoplastic resin, a polystyrene resin is the most common, but a polyester resin, an epoxy resin, an acrylic resin, a urethane resin, or the like is also used. As a coloring agent, carbon black is most widely used, and in the case of a magnetic toner, iron oxide black magnetic powder is often used. In the case of a system using a so-called two-component developer, the toner is usually used by being mixed with carrier particles such as glass beads and iron powder.

[0007] 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 step has often been performed by heat.

When a step of transferring a toner image is provided, a step for removing the residual toner on the photosensitive member is usually provided.

In recent years, the development of monocolor copying to full-color copying in copying machines and the like has been rapidly progressing, and the study and commercialization of two-color copying machines and full-color copying machines have been greatly increased. For example, "Journal of the Society of Electrophotography" Vol.
22, no. 1 (1983) and "Journal of the Institute of Electrophotography" Vo
l 25, No. 1, P52 (1986).

[0010] However, for those who are not immediately compared with the real thing like televisions, photographs, and color prints, and for those who see a color image processed more beautifully than the real thing, full color electrophotography which is currently in practical use is considered. The images are not always satisfactory.

[0011] Color image formation by full-color electrophotography generally reproduces all colors using three primary color toners of yellow, magenta, and cyan.

In the method, first, an electrostatic latent image is formed on a photoconductive layer by passing light from a document through a color separation light transmitting filter having a complementary color relationship with the color of the toner, and then the toner is developed and transferred. Hold on the support. This process is sequentially performed a plurality of times, and while the registration is being performed, the toner is overlaid on the same support, and the final full-color image is obtained by one-time fixing.

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

[0014] To solve the above-mentioned problems, search for a carrier core agent and a carrier coating agent and optimization of the coating amount, or study of a charge control agent and a fluidity imparting agent to be added to the toner, and further, a binder as a base Many studies have been made to achieve excellent triboelectrification in all materials constituting a developer, such as improvement of the developer.

For example, Japanese Patent Publication No. 52-25656 discloses a technique for adding a charge auxiliary agent such as chargeable fine particles to a toner.
And JP-A-56-64352 disclose resin fine powder having a polarity opposite to that of the toner, and JP-A-61-160760.
In Japanese Patent Application Laid-Open Publication No. H11-157, a technique of adding a fluorine-containing compound to a developer to obtain a stable triboelectric charging property is proposed, and even today, many charge assisting agents are being developed.

Further, various techniques have been devised as a method for adding the charging auxiliary as described above. For example, a method of attaching the toner particles to the surface of the toner particles by electrostatic force or van der Waals force between the toner particles and the charge auxiliary agent is generally used, and a stirrer, a mixer or the like is used. However, in this method, it is not easy to uniformly disperse the additives on the surface of the toner particles. It is difficult to avoid. This tendency becomes more conspicuous as the specific electrical resistance of the charging aid increases and as the particle size decreases. In such a case, the performance of the toner is affected. For example, the amount of triboelectric charge becomes unstable, the image density is not constant, and the image has a lot of fog.

[0017] Or, if continuous copying or the like is performed, the content of the charging aid changes, and the image quality at the initial stage cannot be maintained.

As another addition method, there is a method in which a charging auxiliary is added in advance together with a binder resin and a colorant at the time of manufacturing a toner. However, the fact that it is not easy to make the charge control agent uniform, and that it substantially contributes to the chargeability,
Since it is near the surface of the toner particles and the charge auxiliary and charge control agent present inside the particles do not contribute to the charging property, it is not easy to control the amount of the charge auxiliary and the amount of dispersion on the surface. Also, in the toner obtained by such a method, the triboelectric charge amount of the toner is unstable, and it is not easy to obtain a toner satisfying the developer characteristics as described above. The fact is that satisfactory quality has not been obtained.

In recent years, the demand for higher definition and higher image quality of copying machines has been increasing in the market, and in the technical field, attempts have been made to achieve high image quality and color by reducing the particle size of toner. However, as the particle size becomes smaller, the surface area per unit weight tends to increase, and the amount of charge of the toner tends to increase. In addition, since the charged amount of the toner is large, the adhesion between the toners is strong, the fluidity is reduced, and problems occur in the stability of toner supply and in the application of tribo to the supplied toner.

In particular, in the case of a color toner, the following characteristics are strongly desired.

(1) It is necessary that the fixed toner is almost in a state of almost complete melting such that the shape of the toner particles cannot be discriminated so that the toner does not diffusely reflect light and hinder color reproduction. is there.

(2) It must be a colored toner having transparency that does not interfere with the toner layers of different tones under the toner layer.

(3) Each of the constituent toners must have balanced hue and spectral reflection characteristics and sufficient saturation.

From such a viewpoint, many binder resins have been studied, but a toner satisfying all of the above characteristics has not yet been developed. Today, polyester resins are widely used as binder resins for color in the technical field. However, toners made of polyester resins are generally easily affected by temperature and humidity, and have an excessive charge amount under low humidity and high humidity. Under such circumstances, there arises a problem such as insufficient charge amount, and there is an urgent need to develop a color toner having a stable charge amount even in a wide range of environments.

[0025]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner for developing an electrostatic image, which solves the above-mentioned problems.

That is, an object of the present invention is to provide a toner which is hardly influenced by the environment such as temperature and humidity and has a stable triboelectric charging property.

It is a further object of the present invention to provide a toner which has clear image characteristics without fog and has excellent durability stability.

It is a further object of the present invention to provide a toner capable of obtaining a clear color OHP image without smear.

[0029]

According to the present invention, there is provided a toner containing at least a colorant-containing resin particle and an external additive, wherein the external additive has silica and a silane compound or / and a silicone compound on its surface. The present invention relates to a toner characterized in that it is titanium oxide fine particles treated with (1).

Further, the present invention provides at least titanium oxide fine particles A surface-treated with an organic compound and titanium oxide fine particles B surface-treated with an inorganic compound (excluding tin oxide and antimony oxide) and an organic compound. (A present invention 2).

In the present invention, as a result of intensive studies on the stabilization of the chargeability of the color toner, the titanium oxide fine particles surface-treated with silica and a silane compound or a silicone compound as an external additive are used to stabilize the charge and flow. It was found to be extremely effective in terms of imparting properties. (Corresponding to the titanium oxide fine particles B of the present invention 1 and the present invention 2). This cannot be achieved with the generally known hydrophobic silica or titanium oxide as a flow improver.

The reason for this is that the silica fine particles have a strong negative property, and the titanium oxide fine particles have a substantially neutral chargeability, and thus cannot be used as an external additive exhibiting a so-called weak negative property. However, in the present invention, fine particles having moderate negative properties could be achieved by subjecting neutral titanium oxide fine particles to surface treatment with strongly negative silica.

In the present invention, it is particularly preferable to treat silica and a silane compound and / or a silicone compound together in order to prevent coalescence of the particles when the titanium oxide fine particles are taken out from an aqueous system.

The titanium oxide of the present invention is also suitable when the particle size of the toner is reduced. When the particle size of the toner is reduced, the surface area per weight increases, and excessive charging due to rubbing is likely to occur. On the other hand, the effect of the titanium oxide fine particles of the present invention, which can control charging and impart fluidity, is great.

Japanese Patent Application Laid-Open No. Sho 59-52255 proposes a toner containing titanium oxide treated with an alkyl trialkoxysilane as an example of a toner containing hydrophobic titanium oxide. Although the electrophotographic properties have been improved by the addition, the surface activity of titanium oxide is inherently small, and coalesced particles are generated at the processing stage, and the hydrophobicity is not uniform. It was not satisfactory when applied.

On the other hand, treatment of titanium oxide fine particles with silica or silica and alumina is disclosed in JP-A-3-2.
No. 20563, but silica /
The charge of the titanium oxide fine particles can be changed by changing the treatment ratio of alumina, but the surface of the particles is hydrophilic in this state, and it is not always satisfactory in terms of charge deterioration under high humidity.

The present inventors have conducted intensive studies on the charging stability of the toner. As a result, a specific oil or coupling agent was treated as titanium oxide A while hydrolyzing it in an aqueous system. It has been found that titanium oxide having a hydrophobicity of 40 to 80% and a degree of hydrophobicity of 40 to 80% can be subjected to a uniform hydrophobic treatment, and that there is no coalescence of particles. They have found that they are extremely effective in providing fluidity.

That is, in the present invention, both the stabilization of charging and the imparting of fluidity can be achieved by treating with an oil having a specific structure or a coupling agent. Particularly preferred in the present invention are coupling agents represented by the following general formula.

C _n H _{2n + 1} -Si (OC _m H _{2m + 1} ) ₃ n = 4 to 12, m = 1 to 3

Here, when n in the general formula is smaller than 4, the treatment becomes easy, but sufficient hydrophobicity cannot be achieved.
If n is larger than 13, the hydrophobicity is sufficient, but the coalescence of the titanium oxide particles increases, and the ability to impart fluidity is reduced.

On the other hand, if m is larger than 3, the reactivity is lowered and the hydrophobic treatment is not sufficiently performed.

Therefore, in the present invention, n is 4 to 12,
Preferably 4 to 8, m is 1 to 3, preferably 1 to 2.

The treatment amount is 1 to 50 parts by weight, preferably 3 to 40 parts by weight, based on 100 parts by weight of titanium oxide, and the degree of hydrophobicity is 40 to 80%, preferably 50 to 80%.
You can do it.

That is, if the degree of hydrophobicity is less than 40%, the amount of charge is greatly reduced due to long-term storage under high humidity, and a mechanism for accelerating the charge on the hard side is required. If the degree exceeds 80%, it is difficult to control the charging of the titanium oxide itself, and as a result, the toner is charged up under low humidity.

The particle size is 0.0
1 to 0.2 μm is good. If the particle size is larger than 0.2 μm, toner charging due to poor fluidity becomes non-uniform, resulting in toner scattering and fogging. 0.01μ
When it is smaller than m, the toner is easily embedded in the toner surface, and the toner is deteriorated quickly, and the durability is reduced. 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 not particularly limited, but the treatment is carried out by hydrolyzing the coupling agent while mechanically dispersing the titanium oxide in an aqueous system so as to have a primary particle diameter. This method is effective and is preferable in that no solvent is used.

Further, in the present invention, it is desirable that the treated titanium oxide has a light transmittance of 40% or more at a light length of 400 nm.

That is, when the titanium oxide of the present invention is used as a full-color toner, if the transmittance with respect to visible light is poor, the projected image of the OHP is blurred, and a clear image cannot be obtained. The measurement of the transmittance in the present invention was performed with UV2200 manufactured by Shimadzu Corporation.

As the binder 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, styrene-based copolymers such as polystyrene, styrene-butadiene copolymer and styrene-acrylic copolymer, and ethylene-based copolymers such as polyethylene, ethylene-vinyl acetate copolymer and ethylene-vinyl alcohol copolymer Copolymer, phenolic resin, epoxy resin, acrylic phthalate resin, polyamide resin, polyester resin, maleic acid resin and the like. In addition, the production method of any resin is not particularly limited.

The effect of the present invention is remarkable when a polyester resin having a high negative charging ability is used among these resins. That is, the polyester-based resin has excellent fixability and is suitable for a color toner, but has a strong negative charging ability and tends to be excessively charged. However, when the polyester resin is used in the composition of the present invention, the harmful effects are improved and excellent. A toner is obtained.

In particular, the following equation

[0053]

Embedded image

(Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and x +
The average value of y is 2-10. A) 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, phthalic acid) Acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) are more preferred because they have sharp melting properties.

When the toner of the present invention is used as a two-component developer using a carrier, an electrically insulating resin is used as a coating resin on the surface of the carrier, but is appropriately selected depending on a toner material and a carrier core material. . In the present invention, at least one monomer selected from at least an acrylic acid (or an ester thereof) monomer and a methacrylic acid (or an ester thereof) monomer in order to improve the adhesion to the carrier core material surface. Must be contained.
In particular, when a polyester resin particle having a high negative chargeability is used as the toner material, it is preferable to further form a copolymer with a styrene monomer for the purpose of stabilizing the charge, and the copolymerization weight ratio of the styrene monomer is preferable. Is preferably 5 to 70% by weight.

As the monomer for the coating resin of the carrier core material that can be used in the present invention, the styrene monomer includes
For example, styrene monomer, chlorostyrene monomer, α
-Methylstyrene monomer, styrene-chlorostyrene monomer and the like. Examples of the acrylic monomer include, for example, acrylate monomer (methyl acrylate monomer, ethyl acrylate monomer, butyl acrylate monomer, octyl acrylate monomer, phenyl acrylate monomer) And methacrylic acid ester monomers (methyl methacrylate monomer, ethyl methacrylate monomer, butyl methacrylate monomer, phenyl methacrylate monomer).

The carrier core material (magnetic particles) used in the present invention includes, for example, metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth and the like, and their alloys or oxides, which are not oxidized or surface oxidized. Things can be used.
In addition, there is no particular limitation on the manufacturing method.

When a two-component developer is prepared by mixing with the toner according to the present invention, the mixing ratio is preferably 2 to 12% by weight, more 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.
Exceeding fog increases fog and in-machine scattering and shortens the useful life of the developer.

As the colorant used in the present invention, known dyes and pigments, for example, phthalocyanine blue, indaslen blue, peacock blue, permanent red, lake red, rhodamine lake, Hanza 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 reflect sensitively on the permeability of the OHP film.

Additives may be added to the toner of the present invention as needed as long as the properties of the toner are not impaired. Examples of such additives include Teflon, zinc stearate and polyvinylidene fluoride. Lubricants, fixing aids (eg, low molecular weight polyethylene, low molecular weight polypropylene, etc.), and organic resin particles.

In the production of the toner of the present invention, the constituent materials are well kneaded by a hot kneader such as a hot roll, kneader, extruder or the like, and then mechanically pulverized and classified to obtain a toner. After dispersing a material such as a colorant in the method obtained by spray drying, or
After mixing the predetermined material with the monomer that should constitute the binder resin,
Each method such as a polymerization toner production method of obtaining a toner by polymerizing this emulsion suspension can be applied.

The toner according to the present invention may contain a charge control agent 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 in this case include an organic metal complex such as a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex or a zinc complex of di-tert-butylsalicylic acid). When the negative charge control agent is blended in the toner, 0.1 to 10 parts by weight based on 100 parts by weight of the binder resin.
It is advisable to add 0.5 parts by weight, preferably 0.5 to 8 parts by weight.

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. However, the present invention is not necessarily limited to this. In FIG.
2 shows an apparatus for developing an electrostatic image formed on a latent image holding member. Reference numeral 1 denotes a latent image holding member, and a latent image is formed by an electrophotographic process unit or an electrostatic recording unit (not shown). 2
Denotes a developer carrier, which is formed of a nonmagnetic 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 carrier. The supply roller 4 also removes the toner on the developer carrier after development. The toner supplied on the developer carrier is uniformly and thinly applied by the developer application blade 5.
The effective contact pressure between the developer coating blade and the developer carrier is 3 to 250 g / cm, preferably 10 to 120 g / cm, as the linear pressure in the sleeve generatrix direction. If the contact pressure is less than 3 g / cm, it becomes difficult to apply the toner uniformly, and the charge amount distribution of the toner becomes broad, causing fogging and scattering. On the other hand, if the contact pressure exceeds 250 g / cm, a large pressure is applied to the toner, so that the toners are undesirably aggregated or pulverized. By adjusting the contact pressure to 3 to 250 g / cm, it becomes possible to loosen the agglomeration peculiar to the small particle size toner, and it is possible to instantly increase the charge amount of the toner. The developer coating blade is preferably made of a material of a triboelectric series suitable for charging the toner to a desired polarity.

In the present invention, silicone rubber, urethane rubber, styrene-butadiene rubber and the like are preferred.
Further, it may be coated with a polyamide resin or the like. Use of a conductive rubber or the like is preferable because the toner can be prevented from being excessively charged.

In the system proposed in the present invention in which a thin layer of toner is coated on a developer carrier by a blade, the thickness of the toner layer on the developer carrier is adjusted to obtain a sufficient image density. It is necessary to make the length of the gap between the developer carrier and the latent image holding body smaller than the gap length, and to apply an alternating electric field to this gap. That is, by applying an alternating electric field or a developing bias in which a DC electric field is superimposed on the alternating electric field between the developer carrier and the latent image carrier by the bias power source 6 shown in FIG. The transfer of the toner onto the body is facilitated, and a higher quality image can be obtained.

The measurement method of the present invention will be described below.

(1) Measurement of toner particle size: The particle size distribution can be measured by various methods. In the present invention, the measurement is performed using a Coulter counter.

That is, a Coulter counter TA-II (manufactured by Coulter) was used as a measuring device, and an interface (manufactured by Nikkaki) for outputting the number average distribution and volume distribution and a CX-1 personal computer (manufactured by Canon) were connected. The electrolyte is 1% sodium chloride.
% NaCl aqueous solution is prepared. As a measuring method, a surfactant, preferably an alkylbenzene sulfonate, is used as a dispersant in 100 to 150 ml of the electrolytic aqueous solution.
Add 5 ml, and further add 2-20 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 using an ultrasonic disperser, and the volume and number of the toner were measured using the Coulter Counter TA-II, using a 100 μm aperture as the aperture. The volume distribution and number distribution of 〜40 μm were calculated. Then, according to the present invention, the weight-average weight average diameter (D
4) (The median value of each channel is taken as a representative value for each channel), the amount of weight-based coarse powder (1
6.0 μm or more), and the number-based fine powder number (5.04 μm or less) determined from the number distribution.

(2) Measurement of hydrophobicity: The methanol titration test is an experimental test for confirming the hydrophobicity of a titanium oxide fine powder having a hydrophobicized surface.

The "methanol titration test" defined herein for evaluating the degree of hydrophobicity of the treated fine titanium oxide powder is carried out as follows. 0.2 g of the test titanium oxide fine powder was added to 50 m of water in a 250 ml Erlenmeyer flask.
Add to l. Methanol is titrated from the burette until all of the titanium oxide is wetted. At this time, the solution in the flask is constantly stirred with a magnetic stirrer. The end point is observed as the entire amount of titanium oxide fine powder is suspended in the liquid, and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water at the end point.

(3) Transmittance measuring method: 0.10 g of sample 13.20 g of alkyd resin * 1 3.30 g of melamine resin * 2 3.50 g of thinner * 3 50.00 g of glass media * 1 Becsol 1323-60 manufactured by Dainippon Ink -E
L * 2 Super Nippon Ink Super-Beckamine J-820-
60 * 3 Amirac thinner manufactured by Kansai Paint

The above composition was collected in a 150 cc mayonnaise bottle, and mixed with a paint conditioner manufactured by Red Devil Co., Ltd.
Perform time dispersion, and after the dispersion, 2mi
1 with a doctor blade. This is 120 ° C x 1
The sheet is heated for 0 minutes, baked, and the transmittance of this sheet is measured by U-BEST 50 manufactured by JASCO Corporation in the range of 320 to 800 nm, and compared.

[0073]

EXAMPLES "Parts" means "parts by weight".

(Production Example 1 of Titanium Oxide) Particle Size 0.05 μm
m, BET120m ² / g hydrophilic titanium oxide fine particles 1
0 g was dispersed in 1000 cc of pure water, and hydrochloric acid was added thereto to adjust the pH to 2.
And then, 20 wt% with respect to titanium oxide n-C ₄ H ₉ -S
i (OCH ₃ ) ₃ was dispersed in an aqueous system with stirring, added and mixed while hydrolyzing so that the particles did not coalesce, dried and crushed to obtain a hydrophobicity of 70% and an average particle size of 0.05 μm.
m, anatase-type titanium oxide fine particles I having a transmittance of 60% at 400 nm were obtained.

(Production Example 2 of Titanium Oxide) Particle Size 0.1 μm
m, BET 70 m ² / g hydrophilic titanium oxide fine particles 20
g was dispersed in 1000 cc of pure water, an aqueous ammonia solution was added to adjust the pH to 9, and 10 wt% of Si with respect to titanium oxide.
A sodium silicate solution containing O ₂ was added and heated to 90 ° C., a 10% sulfuric acid solution was added dropwise, the pH was gradually lowered to 2, and SiO ₂ was deposited on the titanium oxide fine particles. Thereafter, 10% by weight relative to titanium oxide n-C ₄ H ₉ -S
i (OCH ₃ ) ₃ was added while stirring so that the particles did not coalesce, dried and crushed to obtain anatase type titanium oxide fine particles II having a hydrophobicity of 40% and an average particle size of 0.12 μm.
I got

(Production Example 3 of Titanium Oxide) In Production Example 2, instead of nC ₄ H ₉ —Si (OCH ₃ ) ₃ , dimethyl-type 500 cSt silicone oil was used at pH 5
The degree of hydrophobicity was 3 in the same manner as in Production Example 2 except that
0%, anatase type titanium oxide fine particles III having an average particle size of 0.12 μm were obtained.

(Production Example 4 of Titanium Oxide) In Production Example 2, after depositing SiO ₂ , a sodium aluminate solution containing 5% by weight of Al ₂ O ₃ with respect to titanium oxide was adjusted to pH 4. Then, alumina was precipitated. Thereafter, the pH was maintained at 5, and silicon oil treatment was performed in the same manner as in Production Example 3 to obtain a hydrophobicity of 30% and an average particle size of 0.15 μm.
To obtain titanium oxide fine particles IV.

(Production Example 5 of Titanium Oxide) Production Example 2 was the same as Production Example 2 except that sodium laurate was treated at pH 9 at 10% instead of nC ₄ H ₉ —Si (OCH ₃ ) _3. Similarly, titanium oxide fine particles V having a degree of hydrophobicity of 40% and an average particle size of 0.13 μm were obtained.

(Production Example 6 of Titanium Oxide) The procedure of Production Example 2 was repeated, except that no treatment was performed with nC ₄ H ₉ —Si (OCH ₃ ) ₃ .
Titanium oxide fine particles VI having an average particle size of 0.12 μm were obtained.

(Production Example 7 of Titanium Oxide) In Production Example 2, after depositing SiO ₂ , a sodium aluminate solution containing 5% of Al ₂ O ₃ based on the weight of titanium oxide was adjusted to pH 4. Then, alumina is precipitated, and titanium oxide fine particles V having a hydrophobicity of 0% and an average particle size of 0.15 μm are formed.
II was obtained.

Example 1 Polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid 4 parts Carbon black 4 parts Di-tert-butylsalicylic acid chromium complex 4 parts were sufficiently premixed with a Henschel mixer, and then a three-roll mill The mixture was melt-kneaded at least twice or more, cooled, coarsely pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized by a fine pulverizer using an air jet method. Further, the obtained finely pulverized product was classified to select a particle size of 2 to 10 μm so as to have the particle size distribution of the present invention, thereby obtaining colorant-containing resin particles.

The titanium oxide fine particles II1.
0% was mixed with a Henschel mixer to obtain a black toner. The weight average particle size of this black toner is 7.3 μm
Met.

A copolymer (weight average molecular weight: 200,000) consisting of 75% of methyl methacrylate and 25% of butyl acrylate was added to 5 parts of the toner.
m, 35% or less 4.2%, 35-40 μm 9.5%,
Cu—Zn— having a particle size distribution of not less than 74 μm and 0.2%
A carrier in which 0.5% of an Fe-based ferrite carrier was coated was mixed so that the total amount became 100 parts, to obtain a developer.

Using this developer, a commercially available plain paper color copying machine (Color Laser Copier 300, manufactured by Canon Inc.) was used to set the development contrast to 300 V, at 23 ° C./65%.
Imaged below. The obtained image is Macbeth RD9
The reflection density was measured using an SPI filter on a Model 18 (the same applies to the following image density measurement method). The image density was as high as 1.45, and was clear without any fog. The OHP projection image was also clear and clear. Thereafter, 10,000 copies were further made, during which the density fluctuation was as small as 0.10, and fog and sharpness were equivalent to those at the initial stage. Under low temperature and low humidity (20
Temperature and 10% RH).
V and the image density was 1.4.
2, which indicates that the present invention was effective in controlling the charge amount under low humidity.

Further, even under high temperature and high humidity (30 ° C./80%), when the development contrast was set to 300 V and an image was formed, the image density was 1.49, and a very stable and good image was obtained. Obtained.

Example 2 An image was formed in the same manner as in Example 1 except that titanium oxide III was used. As a result, a good image was obtained although fogging was slightly observed as compared with Example 1. was gotten. The image density under low temperature and low humidity and high temperature and high humidity is 1.
As in Example 1, good results were obtained.

Example 3 An image was formed in the same manner as in Example 1 except that titanium oxide in which silica was increased to 30% was used. Although reduced by 0.1, good results were obtained.

Example 4 A developing device of a commercially available color copying machine (Color Laser Copier 500, manufactured by Canon) was modified as shown in FIG. 1, and 2,000 images were formed in the same manner as in Example 1 except that no carrier was used. Good results were obtained upon dispensing.

Comparative Example 1 Instead of the titanium oxide of Example 1, a hydrophilic titanium oxide (B
When the same procedure as in Example 1 was carried out except using ET130 m ² / g), toner scattering occurred under high temperature and high humidity.

Reference Example In Example 1, when an image was formed in the same manner as in Example 1 except that titanium oxide IV was used, the image density was reduced to 1.25 under low temperature and low humidity.

Comparative Example 2 In Example 1, silica 10% and alumina 10%
When the image was formed in the same manner as in Example 1 except that the titanium oxide treated in Step 1 was used, fogging occurred at high temperature and high humidity.

Example 5 Polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid 3 parts Carbon black 3 parts Di-tert-butylsalicylic acid 4 parts chromium complex salt was sufficiently premixed with a Henschel mixer. The mixture was melt-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 a fine pulverizer using an air jet method. Further, the obtained finely pulverized product was classified to select a particle size of 2 to 10 μm so as to have the particle size distribution of the present invention, thereby obtaining colorant-containing resin particles.

The titanium oxide fine particles I 1.0
% And 0.3% of titanium oxide fine particles II were mixed with a Henschel mixer to obtain a black toner. The weight average particle size of this black toner was 7.3 μm.

To 5 parts of the toner, 1% of methyl methacrylate (weight average molecular weight: 200,000) was added with a weight average particle diameter of 43 μm, 4.8% of 35 μm or less, and 35 to 40 μm 1.
2.6%, C having a particle size distribution of 74 μm or more and substantially 0
The carrier coated on the u-Zn-Fe-based ferrite carrier was mixed so as to be 100 parts in total, to prepare a developer.

Using this developer, a commercially available plain paper color copying machine (Color Laser Copier 300, manufactured by Canon Inc.) was used to set the development contrast to 300 V, at 23 ° C./65%.
Imaged below. The obtained image is Macbeth RD9
The reflection density was measured using an SPI filter with a type 18 (the same applies to the following image density measurement method). This image density was as high as 1.47, and was clear without any fog. The OHP projection image was also clear and clear. Thereafter, 10,000 copies were further made, during which the density fluctuation was as small as 0.10, and fog and sharpness were equivalent to those at the initial stage. In addition, under normal temperature and low humidity (23
Temperature, 5% RH), the development contrast is 300 V
Was set, and the image density was 1.44.
, Suggesting that the present invention was effective in controlling the amount of charge under low humidity.

Further, under high temperature and high humidity (30 ° C./80% RH)
However, similarly, when the development contrast was set to 300 V and an image was formed, the image density was 1.50, and a very stable and good image was obtained.

Further, at 23 ° C./65% RH, at 23 ° C./5
No abnormalities were observed in the initial images after being left for one month in each environment of% RH and 30 ° C./80% RH.

Example 6 An image was formed in the same manner as in Example 1 except that the titanium oxide fine particles III were used in place of the titanium oxide fine particles II used in Example 5, and an image was obtained at 30 ° C./80%. Although the concentration was 1.52 to 1.58, which was slightly higher than that of Example 1, good results were obtained.

Example 7 An image was formed in the same manner as in Example 5 except that the titanium oxide fine particles IV were used instead of the titanium oxide fine particles II used in Example 5, and the reproduction of highlight and the reproducibility of fine lines were improved. Furthermore, the image density is improved by 1.50 to
It was very stable at 1.55.

Example 8 An image was formed in the same manner as in Example 5 except that the titanium oxide fine particles V were used in place of the titanium oxide fine particles II. As a result, fog was slightly noticeable as compared with the case of Example 1. Gave good results.

Example 9 A developing device of a commercially available color copying machine (Color Laser Copier 500, manufactured by Canon) was remodeled as shown in FIG. 1 and 2,000 images were printed in the same manner as in Example 5 except that no carrier was used. Good results were obtained upon dispensing.

Comparative Example 3 An image was formed in the same manner as in Example 5, except that 0.3% of hydrophobic silica (R972, Nippon Aerosil) was used instead of the titanium oxide fine particles II.
The image density in each environment increased to 1.35 to 1.60.

[0103]

Comparative Example 4 An image was formed in the same manner as in Example 5 except that titanium oxide VI treated with only 10% of silica was used, and the image was left at 30 ° C./80% for one month. In this case, toner scattering occurred.

[0105]

According to the present invention, by improving the external additive, that is, by using titanium oxide fine particles having a specific surface treatment, charging stability in various environments can be achieved, and high image density can be obtained. Achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a developing device.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-360152 (JP, A) JP-A-63-142362 (JP, A) JP-A-3-150574 (JP, A) JP-A-4- 170555 (JP, A) JP-A-2-46469 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (5)

(57) [Claims] 1. A toner containing at least a colorant-containing resin particle and an external additive, wherein the external additive is titanium oxide fine particles whose surface is treated with silica and a silane compound or a silicone compound. Toner. 2. The toner according to claim 1 , wherein the titanium oxide fine particles are anatase type titanium oxide. 3. At least titanium oxide fine particles A surface-treated with an organic compound and an inorganic compound (however,
And antimony oxide) and titanium oxide fine particles B surface-treated with an organic compound. 4. The titanium oxide particles A are surface-treated with at least a coupling agent and / or silicone oil, and the titanium oxide particles B are surface-treated with at least silica and a coupling agent and / or silicone oil. The toner according to claim 3, wherein: 5. The toner according to claim 3, wherein the titanium oxide fine particles A are surface-treated with a silane coupling agent and / or silicone oil.