JPH0756380A - Toner - Google Patents

Abstract

PURPOSE:To obtain a toner having always stable triboelectric chargeability not affected by environmental conditions such as temp. and humidity by using fine titanium oxide partices surface-treated with silica, a silane compd. and/or a silicone compd. as an additive. CONSTITUTION:In a toner contg. colorant-contg. resin particles and an additive, fine titanium oxide particles surface-treated with silica, a silane compd. and/or a silicone compd. are used as the additive. The triboelectric chargeability of the toner is stabilized and the flowability can be enhanced. The surface treatment is attained by treating titanium oxide having 0.01-0.2mum average particle diameter and 40-80% hydrophobic degree while hydrolyzing a specified coupling agent or oil in an aq. system. The coupling agent is preferably CnH2n+1- Si(OCmH2m+1)3 (4<=n<=12 and 1<=m<=3).

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. 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 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 used by being mixed with carrier particles such as glass beads and 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, a step for removing the residual toner on the photoconductor is usually provided.

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 to the real thing like a TV, 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-61-160760 disclose resin fine powder having a polarity opposite to that of the toner.
In the publication, a technique is proposed in which a fluorine-containing compound is added to each developer to obtain stable triboelectric charging property, 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 becomes fogged.

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 substantially contributed to the charging property.
It is not near the surface of the toner particles, and the charging aid and charge control agent present inside the particles do not contribute to the charging property, so that 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, particularly in color toners, the following characteristics are strongly desired.

(1) The fixed toner needs to be in a state of almost complete melting such that the shape of the toner particles cannot be discriminated so as not to diffusely reflect light and prevent color reproduction. is there.

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

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

From this point of view, 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.

[0025]

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

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

A further object of the present invention is to provide a toner having clear image characteristics free from fog and excellent in durability stability.

A further object of the present invention is to provide a toner capable of obtaining a clear color OHP image having no turbidity.

[0029]

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

The present invention also relates to a toner containing 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 and an organic compound ( Invention 2).

In the present invention, as a result of extensive studies on stabilization of chargeability of color toners, titanium oxide fine particles surface-treated with silica and a silane compound or a silicone compound as external additives stabilize charge and flow. They have found that they are extremely effective in terms of imparting sex. (Corresponding to titanium oxide fine particles B of present invention 1 and present invention 2). This could not be achieved with generally known hydrophobic silica or titanium oxide as flow improvers.

The reason is that the silica fine particles have a strong negative property and the titanium oxide fine particles have a substantially neutral charging property, and thus cannot be used as an external additive exhibiting a so-called weak negative property. In the present invention, however, fine particles having an appropriate negative property can be achieved by surface-treating the neutral titanium oxide fine particles with the strongly negative silica.

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

The titanium oxide of the present invention is also suitable when the toner has a small particle size. 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 the titanium oxide fine particles of the present invention that can control the charge and impart fluidity is great.

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 various electrophotographic characteristics are certainly improved by the addition, the surface activity of titanium oxide is originally small and coalesced particles are generated at the processing stage, and the hydrophobicity is not uniform, so that it is not always a full-color toner. It was not satisfactory when applied.

On the other hand, it is possible to treat fine particles of titanium oxide with silica or silica and alumina or the like.
No. 20563 suggests that silica /
The charge of titanium oxide fine particles can be changed by changing the treatment ratio of alumina, but the particle surface is hydrophilic as it is, and it is not always satisfactory in terms of charge deterioration under high humidity.

The present inventor has conducted extensive studies on the stability of the charging property of the toner. As a result, the titanium oxide A treated with a specific oil or a coupling agent while hydrolyzing in water has an average particle diameter of 0.01. It was found that titanium oxide having a particle size of ˜0.2 μm and a degree of 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 found that it is extremely effective in terms of imparting liquidity.

That is, according to the present invention, both the stabilization of charging and the imparting of fluidity can be achieved by treating with an oil or a coupling agent having a specific structure. 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

When n in the general formula is smaller than 4, the treatment becomes easy but the hydrophobicity cannot be sufficiently achieved.
Further, when n is larger than 13, 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.

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

The amount of treatment 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, when 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, and the hydrophobicity is increased. If the degree 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.

The particle size is 0.0 from the viewpoint of imparting fluidity.
1 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 0.01μ
If it is smaller than m, the toner is likely to be embedded on the surface of the toner 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 method for treating titanium oxide is not particularly limited, but the treatment is carried out by hydrolyzing the coupling agent while mechanically dispersing titanium oxide in an aqueous system so as to have a primary particle size. The 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 transparency to visible light is poor, the projected image of the OHP will be shaded and a clear toner cannot be obtained. The transmittance of the present invention was measured with UV2200 manufactured by Shimadzu Corporation.

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 great 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

[0053]

[Chemical 1]

(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 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 consisting 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, phthal 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 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.
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 usually 2 to 12% 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 range, fog and 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, induslen 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 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, 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 crushed 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.

The toner according to the present invention may be blended with a charge control agent in order to stabilize the charging 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.

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.

(3) Method for measuring transmittance: Sample 0.10 g Alkyd resin 13.20 g * 1 Melamine resin 3.30 g * 2 Thinner 3.50 g * 3 Glass media 50.00 g * 1 Dainippon Ink & Chemicals Beckosol 1323-60 -E
L * 2 Super Nippon Beckamine J-820 manufactured by Dainippon Ink
60 * 3 Amylak thinner made by Kansai Paint

The above mixture was sampled in a 150 cc mayonnaise bottle, and the mixture was mixed with a paint conditioner manufactured by Red Devil Co. 1
Disperse for 2 hours, and after the dispersion, 2 mi on the PET film.
Apply with a doctor blade of 1. 120 ° C x 1
After heating for 0 minutes and baking, the transmittance of this sheet is measured with U-BEST 50 manufactured by JASCO Corporation in the range of 320 to 800 nm, and the transmittance is compared.

[0073]

EXAMPLES "Parts" means "parts by weight".

(Production Example 1 of titanium oxide) Particle size 0.05 μ
m, BET 120 m ² / g hydrophilic titanium oxide fine particles 1
Disperse 0 g in 1000 cc of pure water, add hydrochloric acid to pH 2
And 20% by weight of n-C ₄ H ₉ -S based on titanium oxide
i (OCH ₃ ) ₃ is dispersed in an aqueous system with stirring, and is added and mixed so that the particles do not coalesce while being hydrolyzed, dried and crushed to have a hydrophobicity of 70% and an average particle size of 0.05 μm.
Anatase type titanium oxide fine particles I having a transmittance of 60% at m and 400 nm were obtained.

(Production Example 2 of titanium oxide) Particle size 0.1 μ
m, BET 70 m ² / g hydrophilic titanium oxide fine particles 20
g in 1000 cc of pure water, pH of the solution is adjusted to 9 by adding an aqueous ammonia solution, and 10% by weight of Si is added 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. Then, 10% by weight of n-C ₄ H ₉ -S based on titanium oxide was used.
While stirring, i (OCH ₃ ) ₃ was added and mixed so that the particles did not coalesce, dried and crushed, and anatase type titanium oxide fine particles II having a hydrophobicity of 40% and an average particle size of 0.12 μm II
Got

(Production Example 3 of Titanium Oxide) In Production Example 2, instead of n-C ₄ H ₉ -Si (OCH ₃ ) ₃ , dimethyl type silicone oil of 500 cSt was added at pH 5.
Hydrophobicity is 3 in the same manner as in Production Example 2 except that
Anatase type titanium oxide fine particles III having 0% and 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 deposited. After that, the pH was maintained at 5, and the same silicone oil treatment as in Production Example 3 was performed to obtain a hydrophobicity of 30% and an average particle size of 0.15 μm.
Titanium oxide fine particles IV were obtained.

Production Example 5 of Titanium Oxide In the same manner as in Production Example 2, except that sodium laurate was treated at 10% at pH 9 instead of silicone oil in Production Example 2, the degree of hydrophobicity was 40% and the average value was 40%. Titanium oxide fine particles V having a particle diameter of 0.13 μm were obtained.

Production Example 6 of Titanium Oxide Titanium oxide fine particles VI having a hydrophobicity of 0% and an average particle size of 0.12 μm were obtained in the same manner as in Production Example 2 except that the silicone oil was not used. It was

(Production Example 7 of Titanium Oxide) In Production Example 2, after depositing SiO ₂ , a sodium aluminate solution containing 5% 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
II was obtained.

Example 1 100 parts of a polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid Carbon black 4 parts 4 parts of a chromium complex salt of di-tert-butylsalicylic acid was sufficiently premixed by a Henschel mixer, and a three-roll mill was used. Were melt-kneaded at least twice with, and after cooling, 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 finely pulverized product thus obtained 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.

Titanium oxide fine particles II 1.
0% was mixed with a Henschel mixer to obtain a black toner. The weight average particle diameter of this black toner is 7.3 μm.
Met.

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 300, 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
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 1.45 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 0.10, and fog and sharpness similar to those at the initial stage were obtained. Under low temperature and low humidity (20
The development contrast is 300 even at
When set to V and image output, the image density was 1.4
It is stable at 2, which suggests that the present invention was effective in controlling the charge amount under low humidity.

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

Example 2 Image formation was carried out in the same manner as in Example 1 except that titanium oxide III was used in Example 1. As a result, although some fog was observed as compared with Example 1, a good image was obtained. was gotten. The image density under low temperature and low humidity and high temperature and high humidity is 1.
41 to 1.52, the same good results as in Example 1 were obtained.

Example 3 Images were produced in the same manner as in Example 1 except that titanium oxide containing 30% of silica was used in Production Example 2. Although it decreased by 0.1, good results were obtained.

Example 4 2000 sheets of images were prepared in the same manner 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. 1 and no carrier was used. When it was put out, good results were obtained.

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

Comparative Example 2 When images were printed in the same manner as in Example 1 except that titanium oxide IV was used, the image density decreased to 1.25 under low temperature and low humidity.

Comparative Example 3 In Example 1, 10% silica and 10% alumina
When image formation was performed in the same manner as in Example 1 except that the titanium oxide treated in step 1 was used, fogging occurred under high temperature and high humidity.

Example 5 Polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid Carbon black 3 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 finely pulverized product thus obtained 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.

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

To 5 parts of this toner, methylmethacrylate (weight average molecular weight 200,000) 1%, weight average particle diameter 43 μm, 35 μm or less 4.8%, 35-40 μm 1
2.6%, C with a particle size distribution of 74 μm or more and substantially zero
A carrier coated with a u-Zn-Fe-based ferrite carrier was mixed in a total amount of 100 parts to prepare a developer.

Using this developer, a commercially available plain paper color copying machine (color laser copier 300, 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
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 1.47 and was clear without any fog. Also, the OHP projection image was clear and had no dust. After that, 10,000 more copies were made, but the density fluctuation during that period was as small as 0.10, and fog and sharpness similar to those at the initial stage were obtained. Under normal temperature and low humidity (23
Development contrast of 300V even at 5 ° C and 5% RH)
When set to, the image density is 1.44.
It is stable, suggesting that the present invention was effective in controlling the charge amount under low humidity.

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

Furthermore, 23 ° C./65% RH, 23 ° C./5
No abnormality was observed in the initial image after being left for 1 month in each environment of% RH and 30 ° C./80% RH.

Example 6 Image formation was carried out 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 at 30 ° C./80% was obtained. The concentration was 1.52 to 1.58, which was slightly higher than that of Example 1, but good results were obtained.

Example 7 Images were produced 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 highlight reproduction and the fine line reproducibility were found. Further improved, the image density is 1.50 in each environment.
It was very stable at 1.55.

Example 8 Image formation was carried out in the same manner as in Example 5 except that titanium oxide fine particles V were used instead of titanium oxide fine particles II. As a result, fog became slightly more noticeable than in Example 1. Was obtained with good results.

Example 9 2000 sheets of images were prepared in the same manner as in Example 5 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. 1 and no carrier was used. When it was put out, good results were obtained.

Comparative Example 4 Image formation was carried out in the same manner as in Example 5 except that 0.3% of hydrophobic silica (R972, Nippon Aerosil) was used in place of the titanium oxide fine particles II,
The image density in each environment is as large as 1.35 to 1.60.

Comparative Example 5 Image formation was performed in the same manner as in Example 1 except that the hydrophobic silica of Comparative Example 1 was used in place of the titanium oxide fine particles I in Example 5, and the image density in each environment was 1.
It has spread further from 27 to 1.65.

Comparative Example 6 Image formation was carried out in the same manner as in Example 5 except that titanium oxide VI treated with only 10% silica was used, and the mixture was left at 30 ° C./80% for 1 month. In that case, toner scattering occurs.

[0105]

INDUSTRIAL APPLICABILITY According to the present invention, by improving the external additive, that is, by using the titanium oxide fine particles having a specific surface treatment, it is possible to stabilize the charge in various environments and to obtain a high image density. To be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a developing device.

Claims (5)

[Claims] 1. A toner containing at least colorant-containing resin particles 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. And toner. 2. The toner according to claim 2, wherein the titanium oxide fine particles are anatase type titanium oxide. 3. A toner comprising 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 and an organic compound. 4. The titanium oxide fine particles A are at least surface-treated with a coupling agent and / or oil, and the titanium oxide fine particles B are at least surface-treated with silica and a coupling agent or / and oil. The toner according to claim 3, wherein the toner is a toner. 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.