JP2003076058A - Electrostatic image developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer having excellent fluidity, cleaning property and uniform and stable electrified charges by adding specified particles. SOLUTION: The electrostatic image developer is characterized in that it contains complex oxide fine particles of amorphous spheric silica and titanium oxide which are prepared by spraying and combusting siloxane and an organic titanium compound in flames and which have 10 to 300 nm particle size, 10 to 100 m<2> /g specific surface area and 1 to 99 wt.% titanium oxide content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developer used for developing an electrostatic charge image in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art Dry developers used in electrophotography and the like are
In the case of performing one-component developer using the toner itself in which the colorant is dispersed in the binder resin and two-component developer in which the toner is mixed with the carrier, and performing the copying operation using these developers. In order to have process compatibility, it is necessary that the developer has excellent fluidity, anti-caking property, fixing property, charging property, cleaning property and the like.

These fluidity, anti-caking property, fixing property,
For the purpose of improving the cleaning property, adjusting the charging property, and stabilizing it, inorganic fine particles such as silica, titanium oxide, and alumina having a particle size smaller than that of the toner particles are added as a so-called external additive. There is.

[0004]

In recent years, the copying speed has been increased, and there is a further demand for improvement of fluidity and cleaning property, and stabilization and uniformity of charging property. In addition, although a small particle size toner has been used for higher image quality, the small particle size toner has poor powder fluidity as compared with a commonly used particle size toner, and thus has a low charging property. It is easily affected by additives such as external additives. Therefore, depending on the type and particle size of the inorganic fine particles such as silica fine particles added to the toner, satisfactory results cannot be obtained in terms of fluidity, chargeability and cleaning property, and it is important to select the inorganic fine particles to be added. . Usually used silica fine particles have a small average particle diameter of primary particles of 10 to 20 nm, so that the particles have a strong cohesive property, the silica fine particles have poor dispersibility, and fluidity and cleaning properties cannot be sufficiently exhibited. There is a problem. Further, by using the spherical silica fine particles, the effect of improving the fluidity and increasing the charge amount can be obtained, but if the charge amount becomes excessive, the electrostatic adhesion force with the toner carrier becomes strong and the developability deteriorates. , The image density becomes thin, and uneven density occurs. Further, if the silica fine particles used contain impurities, the chargeability of the developer is affected.

On the other hand, for the purpose of controlling the amount of charge, low-charge titanium oxide fine particles are further added. However, since the crystalline titanium oxide fine particles that have been conventionally used have a non-spherical particle shape, they have poor fluidity and dispersibility, and if a large amount of crystalline titanium oxide fine particles are added to adjust the charge amount, the fluidity becomes poor. Is deteriorated, and due to poor dispersion, the developer is liable to be released from the toner carrier, causing fog (background stain) in the image. Therefore, a method has been adopted in which the fluidity takes advantage of spherical silica fine particles and the charge amount is adjusted by blending silica fine particles and titanium oxide fine particles. However, in order to exhibit these functions sufficiently stably, it is necessary that the fine particles of titanium and the fine particles of titanium oxide are uniformly and completely mixed in a predetermined mixing ratio, but it is difficult to completely mix the fine particles. However, there is a problem that segregation occurs and the chargeability is likely to locally vary.

Therefore, in view of the above problems, an object of the present invention is to provide an electrostatic image developer which is excellent in fluidity and cleaning property and has stable charging property.

[0007]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of intensive studies to achieve the above object, the present inventors have found that siloxane and an organotitanium compound are used as inorganic fine particles to be added to toner particles. Obtained by spray combustion in a flame, the particle size is 10 to 300 nm, the specific surface area is 10 to 100 m ² / g, and the titanium oxide is 1 to 99% by weight.
It was found that by adding the complex oxide fine particles of amorphous spherical silica / titanium oxide contained therein, an electrostatic charge image developer having excellent fluidity and cleaning property, and having uniform and stable charging property can be obtained. Invented.

Accordingly, the present invention provides the following electrostatic image developer. (1) Obtained by spray burning siloxane and an organotitanium compound in a flame, having a particle size of 10 to 300 nm, a specific surface area of 10 to 100 m ² / g, and a titanium oxide content of 1 to 99% by weight.
An electrostatic charge image developer characterized by containing a complex oxide fine particle of amorphous spherical silica / titanium oxide contained. (2) The electrostatic image developer according to (1), wherein the composite oxide fine particles are substantially free of chlorine. (3) The electrostatic image developer according to (1) or (2), wherein the organic titanium compound is a tetraalkoxy titanium compound, a titanium acylate compound, an alkyl titanium compound or a titanium chelate compound. (4) The composite oxide fine particles are produced by simultaneously spraying siloxane and an organic titanium compound and oxidizing and burning in a flame. At that time, the siloxane, the organic titanium compound, the supporting gas, and the combustion supporting gas supplied to the burner are produced. The electrostatic charge image according to (1), (2) or (3), characterized in that the adiabatic flame temperature of combustion of siloxane, organotitanium compound, and auxiliary combustion gas is set to 1,650 ° C. or more and 4,000 ° C. or less by reference. Developer. (5) Complex oxide fine particles are formed on the surface by the following formula (1).

[Chemical 2] (In the formula, R ¹ , R ² and R ³ are the same or different from each other and represent an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, x,
y and z are integers of 0 to 3, and x + y + z = 1 to 3. The electrostatic charge image developer according to any one of (1) to (4), which is a hydrophobized fine particle into which a unit represented by (4) is introduced.

The present invention will be described in more detail below.
The electrostatic image developer of the present invention can be obtained by adding spherical complex oxide fine particles of silica and titanium oxide to toner particles. As the toner particles, known particles composed mainly of a binder resin and a colorant can be used, and a charge control agent may be added if necessary. The binder resin used for this toner is not particularly limited, and examples thereof include styrenes such as styrene, chlorostyrene and vinylstyrene, monoolefins such as ethylene, propylene, butylene and isobutylene, vinyl acetate and propion. Vinyl esters such as vinyl acrylate, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate , Acrylic acid (methacrylic acid) such as dodecyl methacrylate
, Vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether and other vinyl ethers, vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone and other vinyl ketone homopolymers or copolymers can be exemplified. Representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene. . Further, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin, wax and the like can also be used.

The colorant used in the toner is not particularly limited, but carbon black,
Nigrosine dye, aniline blue, calcoil blue,
Typical examples are chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black and rose bengal. Further, as the toner powder, a magnetic toner powder containing a magnetic material can be used.

The spherical composite oxide fine particles of silica and titanium oxide used in the present invention are produced by simultaneously spraying siloxane and an organotitanium compound and oxidatively burning in a flame.

The siloxane used here is a halogen-free general formula (2) (R ⁴ ) ₃ SiO [SiR ⁵ R ⁶ O] _m Si (R ⁴ ) ₃ (2) (wherein R ⁴ , R ⁵ and R ^{6, which} may be the same or different, each represents a monovalent hydrocarbon group, an alkoxy group, or a hydrogen atom and is an integer of m ≧ 0.), A cyclic organo represented by the following general formula (3) [SiR ⁵ R ⁶ O] _n (3) (in the formula, R ⁵ and R ⁶ have the same meanings as described above, and n is an integer of 3). Organopolysiloxanes such as siloxanes or mixtures thereof may be mentioned.

Here, examples of the monovalent hydrocarbon group of R ^{4 to} R ⁶ include alkyl groups having 1 to 6 carbon atoms, alkenyl groups such as vinyl group, and phenyl groups, among which methyl,
A lower alkyl group such as ethyl and propyl, particularly a methyl group is preferable. Examples of the alkoxy group include those having 1 to 6 carbon atoms such as methoxy and ethoxy, and the methoxy group is particularly preferable. m is an integer of m ≧ 0, preferably an integer of 0 to 100, more preferably an integer of 0 to 10. Further, n is an integer of n ≧ 3, preferably 3 to
It is an integer of 10, more preferably an integer of 3 to 7.

Examples of the above-mentioned organosiloxanes include hexamethyldisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. These siloxanes preferably do not contain halogen such as chlorine and are obtained by purification.

On the other hand, as the organotitanium compound, a tetraalkoxytitanium compound, a titanium acylate compound, an alkyltitanium compound, a titanium chelate compound, or the like is used, and those containing substantially no chlorine are preferable. Specifically, the following general formula (4) Ti (OR ⁷ ) ₄ (4) (In the formula, OR ⁷ represents an alkoxy group, and carbon such as methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, etc. A tetraalkoxytitanium compound represented by the formulas 1 to 8), the following general formula (5) Ti (OCOR ⁸ ) ₄ (5) (in the formula, COR ⁸ represents an acyl group, and a formyl group. ,
Examples thereof include an acetyl group, a propionyl group, a butyryl group, a valeryl group, a caproyl group, a heptanoyl group and an octanoyl group. ), A titanium acylate compound represented by the following general formula (6) TiR ⁹ ₄ (6) (wherein R ⁹ represents an alkyl group, such as a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group). Carbon number 1
~ 8 are mentioned. ), An alkyl titanium compound represented by the following general formula (7) or (8) (R ¹⁰ O) ₂ Ti (OR ¹¹ OH) ₂ (7) (R ¹⁰ O) ₂ Ti (OR ¹¹ NH ₂ ) ₂ ( 8) (In the formula, OR ¹⁰ represents an alkoxy group, and examples thereof include those having 1 to 8 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a butoxy group, and R ¹¹ is an alkylene group and methylene. Group, ethylene group, trimethylene group,
1 to 4 carbon atoms such as tetramethylene group and methylethylene group
8 are listed. ) A titanium chelate compound represented by

Of these organic titanium compounds, those which are solid at room temperature are siloxanes, alcohols such as methanol, ethanol, propanol and butanol, and toluene,
It is preferable to use it by dissolving it in a hydrocarbon solvent such as xylene.In addition, as the molecular weight of the organic titanium compound increases, the production rate of titanium oxide per organic titanium compound of the raw material decreases, and the economy is poor, so it is liquid. In terms of economic efficiency, an organic titanium compound having a titanium oxide production rate of 0.2 or more is preferable. These organotitanium compounds do not contain chlorine, are obtained by purification, and are substantially free of impurities and have high purity, and thus are suitable as a raw material for complexing.

These siloxanes and organotitanium compounds may be mixed in a liquid state or introduced individually into a burner and sprayed by a nozzle attached to the burner. The content of titanium oxide is preferably 1 to 99% by weight, preferably 5 to 95% by weight, in order to impart the function of titanium oxide combined with the properties of silica, so that the combustion oxide has a stoichiometric ratio. Siloxane and an organotitanium compound may be supplied.

In the method of spraying in a liquid form, there is a method of spraying with a nozzle using a spray medium such as air or steam. When an organic titanium compound having a property of being easily hydrolyzed is used, the spray medium is dehumidified. Preferably, compressed air or nitrogen is used. Further, as a method of spraying, there are a method using the pressure of the liquid itself and a method using centrifugal force, and any of these methods may be used. The sprayed droplets are preferably finely divided to completely evaporate, pyrolyze and burn, and have a size of 100 μm or less, preferably 50 μm or less. Therefore, the viscosity of the raw material liquid (siloxane, organic titanium compound) at 500C is preferably 500 cs or less, and more preferably 200 cs or less.

The sprayed droplets of the siloxane and the organotitanium compound receive heat from the auxiliary flame and the self-combustion flame of the auxiliary combustion gas, and are oxidatively burned while the droplets are vaporized or thermally decomposed. Since titanium oxide is simultaneously synthesized from the compound in the gas phase and fused, spherical composite oxide fine particles in which silica and titanium oxide are compounded are obtained.

The core particles of silica and titanium oxide produced by combustion are the temperature of the flame, the force of sill and the concentration of titanium oxide.
The final particle size is determined by the coalescence growth due to the residence time in the flame, and the influence of the flame temperature is particularly large. When the flame temperature is low, the particle size is 10 nm, similar to fumed silica.
In order to bring the particles closer to each other and to further increase the size of the particles, it is preferable to carry out coalescence growth in a high flame temperature of 1,423 ° C. or more of the melting point of silica, and more preferably 1,640 ° C. or more of the melting point of titanium oxide.

The heat of combustion and the amount of excess oxygen (air) have a great influence on the flame temperature. The combustion heat is determined by the type and supply amount of siloxane, organic titanium compound, and combustion-enhancing gas when complete combustion is performed. The combustion heat of the siloxane that serves as the silica source is, for example, 1% with linear hexamethyldisiloxane.
389 kcal / mol, 8,550 kcal / kg,
Cyclic octamethylcyclotetrasiloxane is 1,97
It is 4 kcal / mol and 6,650 kcal / kg, and a large combustion heat can be obtained and energy efficiency is excellent. The heat of combustion of the organic titanium compound is, for example, 1,623 kcal / mo for tetraisopropoxy titanium.
1, 5,710 kcal / kg, 2,209 kcal / mol with tetrabutoxytitanium, 6,490 kcal / kg
2,112 with titanium acetylacetonate (titanium diisopropoxybisacetylacetonate)
kcal / mol, 5,800 kcal / kg,
Similar to siloxane, an organotitanium compound obtains a large heat of combustion. By simultaneously burning the siloxane and the organotitanium compound, a combustion flame having high thermal energy efficiency is formed, and spheroidization of the produced particles is promoted.

In order to keep combustion of the siloxane and the organotitanium compound stable and complete combustion, an auxiliary flame is formed by using an auxiliary combustion gas. Here, the auxiliary gas may be one that does not leave a residue after combustion, and may be hydrogen or a hydrocarbon gas such as methane, propane, butane,
There is no particular limitation.

However, if there is a large amount of supporting gas, the combustion exhaust gas increases due to carbon dioxide, water vapor, etc., which are by-products of combustion.
Since the concentration of silica and titanium oxide during combustion decreases,
The amount of the supporting gas used is 2 mol or less, preferably 0.1 to 1.5 mol, per mol of the raw material siloxane and the organic titanium compound.

The combustion-supporting gas added at the time of combustion may be oxygen or an oxygen-containing gas such as air.
When the amount of net oxygen is insufficient, combustion of combustible gas (auxiliary gas) used for siloxane, organotitanium compound, and auxiliary flame becomes incomplete, and carbon content remains in the product. If the amount increases, the concentration of silica and titanium oxide in the flame will decrease and the flame temperature will decrease, tending to suppress the coalescence growth of generated particles.If a large excess of combustion-supporting gas is supplied, the siloxane and organotitanium compounds will increase. Combustion becomes incomplete, the load of the powder collecting equipment of the exhaust system increases, and it becomes unfavorable. Also, in order to raise the flame temperature, the combustion supporting gas is oxygen and the theoretical amount of oxygen is supplied to obtain the highest flame temperature, but combustion tends to be incomplete, and a slight excess of oxygen is required for complete combustion. is necessary. Therefore, the combustion-supporting gas supplied from the burner is 1.0 to 4.0 times mol of the theoretical oxygen amount required for combustion,
Preferably, 1.1 to 3.0 times the molar amount of oxygen may be included.

The combustion-supporting gas may be supplied from the burner, or may be supplemented by taking in outside air along the burner.

The spherical composite oxide fine particles of silica and titanium oxide used in the present invention have a particle size of less than 10 nm, and a specific surface area of more than 100 m ² / g tends to cause aggregation, resulting in flow of the developer. Property, caking resistance, and fixability are not obtained, and on the other hand, when the particle size is larger than 300 nm and the specific surface area is smaller than 10 m ² / g, there arises a problem that the photoreceptor is denatured and scraped, and the adhesion to the toner is lowered. Therefore, the particle size is required to be 10 to 300 nm, and more preferably 20 to 300 nm. The specific surface area is 10 to 100 m ² / g, and more preferably 15 to 90 m ² / g.

In order to adjust the particle size of the composite oxide fine particles produced by combustion, the flame temperature, the concentration of silica and titanium oxide, and the residence time in the flame may be adjusted.
In the present invention, in order to control the flame temperature, siloxane supplied to the burner, an organotitanium compound, a supporting gas,
Controls the adiabatic flame temperature calculated by supporting gas standard. Here, the adiabatic flame temperature is regarded as an adiabatic system,
What is generated or left after combustion is the temperature reached by consuming heat due to the amount of heat obtained by combustion. Therefore, the adiabatic flame temperature is determined by the siloxane supplied to the burner,
Q is the amount of combustion heat of the organic titanium compound and supporting gas
_{When 1} , Q ₂ , Q ₃ (kcal / HR) are set, the total combustion heat quantity Q is Q ₁ + Q ₂ + Q ₃ .

On the other hand, the amounts of silica, titanium oxide, water vapor, carbon dioxide, oxygen, and nitrogen produced, by-produced, and left by combustion per hour are N ₁ , N ₂ , N ₃ , N ₄ , N ₅ , and N _6. (Mol
/ HR), specific heat of Cp ₁ , Cp ₂ , Cp ₃ , Cp ₄ , C
p ₅ , Cp ₆ (kcal / mol ° C), adiabatic flame temperature t
a (° C.), when the room temperature is 25 ° C., the combustion heat amount and the consumed heat amount are equivalent, and Q = (N ₁ Cp ₁ + N ₂ Cp ₂ + N ₃ Cp ₃ + N ₄ Cp ₄ + N ₅
Cp ₅ + N ₆ Cp ₆ ) (ta-25) is obtained.

Furthermore, the JANAF (Joint Arm)
According to the thermo-chemical table of y-Navy-Air-Force), the absolute temperature of 298 ° K (=
Absolute temperature T ° K (T = t ° C + 27)
3) Standard enthalpy difference H ° _T- H ₂₉₈ (kJ / mo)
1) is shown, that is, if the amount of heat consumed to reach t ° C. (t = T ° K-273) from 25 ° C. per mol of a certain chemical substance is E (kcal / mol), E = CP (t-25) = (H ° T -H 298) × 0.238
9 (however, 1 kJ = 0.2389 kcal) is easily obtained.

Thus, the above formula is for silica, titanium oxide,
Water vapor, carbon dioxide, oxygen, nitrogen 298 ° K (25
C) to T ° K (T = 273 + t ° C), and the heat consumption per mole is E ₁ , E ₂ , E ₃ , E ₄ , E ₅ , E ₆ (k
cal / mol), the temperature at which Q = N ₁ E ₁ + N ₂ E ₂ + N ₃ E ₃ + N ₄ E ₄ + N ₅ E ₅ + N ₆ E ₆ is the adiabatic flame temperature ta.

Specifically, the adiabatic flame temperature may be controlled by adjusting the types and supply amounts of siloxane and the organic titanium compound, the oxygen supply ratio, and the like. When a large amount of inert gas that does not participate in combustion such as excess oxygen or nitrogen is supplied from the burner, the flame temperature decreases, and the spherical complex oxide fine particles of silica and titanium oxide become fine, and the complex oxide fine particles coalesce with each other. Growth is impaired and aggregates are formed, and the load on the exhaust collection system is increased. When the adiabatic flame temperature of combustion of siloxane, organotitanium compound, and auxiliary combustion gas is less than 1,650 ° C., the fine particles of complex oxide become fine, based on the siloxane, organic titanium compound, auxiliary combustion gas, and supporting gas supplied to the burner.
The integration due to coalescence of particles does not occur, it becomes an aggregate, the effect of improving fluidity is not obtained, and productivity,
Adiabatic flame temperature is 1,6 due to poor energy efficiency
It is desirable that the temperature is 50 ° C. or higher, preferably 1,700 ° C. or higher. Also, by reducing the amount of inert gas and combustion-supporting gas, the adiabatic flame temperature rises and the generated particle size increases, but when the adiabatic flame temperature exceeds 4,000 ° C, the particle size is larger than 300 nm and the specific surface area is large. Is less than 10 m ² / g, the adiabatic flame temperature is 4,000 ° C or less,
The temperature is preferably 3,800 ° C or lower.

In addition, there is no limitation on the introduction of an inert gas such as air or nitrogen in order to prevent the powder from adhering to the wall of the combustion furnace or to cool the exhaust gas after combustion. The spherical composite oxide fine particles obtained by combustion are entrained in the exhaust gas, and are separated and collected by a cyclone, an air flow classifier, a bag filter, etc. provided in the exhaust gas and collected.

In this way, the particle size is 10 to 300 n.
m, specific surface area 10 to 100 m ² / g, titanium oxide 1
It is possible to produce spherical composite oxide fine particles of silica and titanium oxide which are contained in an amount of about 99 wt% and substantially do not contain chlorine.

The spherical complex oxide fine particles of silica and titanium oxide used in the present invention have the following formula (1) on the surface thereof in order to eliminate the change in the charge amount due to temperature and humidity.

[Chemical 3] (In the formula, R ¹ , R ² and R ³ are the same or different from each other and represent an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, x,
y and z are integers of 0 to 3, and x + y + z = 1 to 3. It is preferable that the unit is a hydrophobized fine particle into which a unit represented by (4) is introduced.

Here, R ¹ , R ² and R ³ are, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and a cyclohexyl group, an aryl group such as a phenyl group, a vinyl group. Group, an alkenyl group such as an allyl group, and the like, and a methyl group is particularly preferable. The unit introduction of the formula (1) may be performed according to a known surface modification method for silica fine powder. Thus, for example the general formula R ¹ ₃ SiN
The silazane compound represented by HSiR ¹ ₃ in the presence of water, vapor, heated at 50 to 400 ° C. in the liquid phase or solid phase, it may be carried out by removing excess silazane compound.

Examples of the silazane compound represented by the general formula R ¹ ₃ SiNHSiR ¹ ₃ include hexamethyldisilazane, hexaethyldisilazane, hexapropyldisilazane, hexabutyldisilazane, hexapentyldisilazane, hexahexyl. Examples thereof include disilazane, hexacyclohexyldisilazane, hexaphenyldisilazane, divinyltetramethyldisilazane, dimethyltetravinyldisilazane, and the like. Particularly, hexamethyldisilazane is preferable from the viewpoint of hydrophobicity after modification and easy removal thereof.

The electrostatic image developer of the present invention can be obtained by adding the above-mentioned spherical complex oxide fine particles to the toner particles, and the compounding amount of the spherical complex oxide fine particles is 0 with respect to 100 parts by weight of the toner. If it is less than 0.01 part by weight, the fluidity of the toner will be insufficient, and if it is more than 20 parts by weight, the charging property will be adversely affected. Therefore, the compounding amount of the spherical complex oxide fine particles is 0 with respect to 100 parts by weight of the toner. The range of 0.01 to 20 parts by weight is preferable, and the range of 0.1 to 10 parts by weight is more preferable. In addition, if necessary, a charge control agent, a release agent,
Additives such as wax can also be added.

This mixing method may be carried out by any method, for example, V type, double cone type container rotary type mixer, ribbon type, screw type mixer with stirring blades, high speed shear flow mixer, ball mill. It can be done by
The spherical complex oxide fine particles may be attached to the surface of the toner particles or may be fused.

The electrostatic image developer containing the spherical composite oxide fine particles of silica and titanium oxide of the present invention can be used as a one-component developer, but it can also be used as a two-component developer by mixing it with a carrier. it can.

When used as a two-component developer, the spherical complex oxide fine particles may not be added to the toner in advance, but may be added when the toner and the carrier are mixed to coat the surface of the toner.

The carrier is a particle whose average particle diameter is almost the same as the particle diameter of the toner or is up to 300 μm, and iron, nickel, cobalt, iron oxide, ferrite,
Known materials such as glass beads and granular silicon are exemplified, but the surface thereof may be coated with a fluororesin, an acrylic resin, a silicone resin or the like.

The electrostatic image developer of the present invention can be used for developing an electrostatic latent image formed on a photoconductor or an electrostatic recording material. That is, an electrostatic latent image is electrophotographically formed on a photoreceptor made of an inorganic photoconductive material such as selenium, zinc oxide, cadmium sulfide, or amorphous silicon, or an organic photoconductive material such as a phthalocyanine pigment or a bisazo pigment. An electrostatic latent image is formed on a electrostatic recording material having a derivative such as polyethylene terephthalate with a needle electrode or the like, and the electrostatic latent image of the present invention is formed on the electrostatic latent image by a developing method such as a magnetic brush method, a cascade method or a touchdown method. The charge image developer is applied and the toner is applied.

After this toner image is transferred to a transfer material such as paper,
The toner is fixed to form a copy, but the toner remaining on the surface of the photoconductor or the like can be cleaned by a blade method, a brush method, a web method, a roll method, or the like.

[0044]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Examples 1 to 8 Hexamethyldisiloxane or octamethylcyclotetrasiloxane and tetraisopropoxytitanium or titanium acetylacetonate (titanium diisopropoxybisacetylacetonate)
At room temperature, the liquid mixture is supplied to a burner installed at the top of the vertical combustion furnace, and atomized by the air of the atomizing medium in the atomizing nozzle attached to the tip of the burner to atomize the fine droplets. It was burned with an auxiliary flame. Oxygen and air were supplied as burnable gases from the burner. At this time, the mixing ratio of hexamethyldisiloxane or octamethylcyclotetrasiloxane, tetraisopropoxy titanium or titanium acetylacetonate, the mixed raw material liquid, propane, oxygen, the supply amount of air including atomization and the adiabatic flame temperature are shown. 1 and Table 2.

Table 3 shows an example of calculation of the adiabatic flame temperature in Example 1.

The silica-titanium oxide spherical composite oxide fine powder thus produced was collected by a bag filter and collected. 500 g of this spherical complex oxide fine powder was charged into a high-speed stirring mixer with a heating / cooling jacket of 5 liters, and 500
r. p. m. While stirring at 25 g, 25 g of pure water was spray-supplied in a sealed manner, and then stirring was continued for 10 minutes. Subsequently, 25 g of hexamethyldisilazane was added, and the mixture was stirred for 60 minutes under a closed condition, and then heated with stirring to remove the produced ammonia gas and the residual treatment agent while aeration with nitrogen at 150 ° C. A fine spherical powder of complex oxide was obtained.

B of the resulting hydrophobized spherical composite oxide fine powder
The ET specific surface area was measured with Micro Soap 4232II (manufactured by Mike Mouth, Data), and the particle size was measured by an electron microscope (SE
M), and the particle shape was measured from the obtained photograph with an analyzer Luzex F (Nireco Co.). As a result, all the particles were spherical with a sphericity represented by the ratio of the short diameter to the long diameter of 0.85 or more. It was The measurement results of titanium oxide content, specific surface area, and particle size are shown in Tables 1 and 2. The chlorine content of impurities was measured by ion chromatography and found to be less than 0.1 ppm.

Next, 96 parts by weight of a polyester resin having a Tg of 60 ° C. and a softening point of 110 ° C. and 4 parts by weight of Carmine 6BC as a coloring material were added, melt-kneaded, pulverized and classified to obtain a toner having an average particle diameter of 7 μm. . 40 g of this toner was mixed with 1 g of the above hydrophobized spherical composite oxide fine powder in a sample mill to prepare a developer. The fluidity, the cleaning property, and the stability of the charge amount of the obtained developer were evaluated by the following methods. The evaluation results are shown in Tables 1 and 2.

[Comparative Example 1] [0050] Except that the adiabatic flame temperature was less than 1,650 ° C by increasing the supply amounts of oxygen and air during spray combustion, the hydrophobic treatment conditions and the addition amount to the toner were used in Example 1.
A developer was prepared in the same manner as in. Raw material supply at combustion,
Table 2 shows the burner gas conditions, the adiabatic flame temperature, the specific surface area of the hydrophobized fine particles, the particle size distribution, the developer fluidity, the cleaning property, and the stability of the charge amount.

Comparative Example 2 Without adding an organic titanium compound,
A developer was prepared in the same manner as in Example 1 except that the fine powder of spherical silica containing no titanium oxide was prepared by spraying and burning only with hexamethyldisiloxane to prepare the developer under the same hydrophobizing conditions and in the same amount as in Example 1. Table 2 shows the evaluation results of the raw material supply amount at the time of combustion, the burner gas conditions, the adiabatic flame temperature, the specific surface area of the hydrophobized fine particles, the particle size distribution, the fluidity of the developer, the cleaning property and the stability of the charge amount.

<Evaluation Method of Flowability> The degree of aggregation was measured to evaluate the flowability. Multi-tester (Measuring Co., Ltd.)
(Made by Seishin Enterprise) was used. That is, 3 g of the developer is sieved from the top, sieves having openings of 250 μm, 150 μm, and 75 μm are stacked in this order from the top, placed on the measurement unit, and an amplitude of 1 m
The weight of the powder remaining on the upper, middle and lower sieves is W ₁ (g), W ₂ (g) and W, respectively.
_The degree of aggregation at ₃ (g) was determined by the following formula. It is considered that the cohesion degree is preferably less than 6%. Aggregation degree (%) = (W ₁ + W ₂ × 0.6 + W ₃ × 0.2) ×
100/3

<Evaluation Method of Cleaning Property> A printer using an organic photoreceptor and a carrier in which a developer and a 50 μm ferrite core are coated with a perfluoroalkyl acrylate resin and an acrylic resin are used per 8 parts by weight of the developer.
A two-component developer was prepared by mixing in a ratio of parts by weight. A print test was performed on 10,000 sheets using the two-component developer as a starting agent and the developer as a replenisher in a two-component developing machine. At this time, the adhesion of the developer to the photoconductor was detected as white spots in the entire solid image.

<Evaluation Method of Stability of Charge Amount> The one-component developer of the above-mentioned example was charged into a one-component developing machine, a print test was conducted on 10,000 sheets, and images transferred and fixed on plain paper were tested. The fog level was measured with a color difference meter.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

EFFECTS OF THE INVENTION According to the present invention, a purified halogen-free siloxane or organotitanium compound is used as a raw material, so that it is substantially chlorine-free and has high purity amorphous silica and titanium oxide. Spherical complex oxide fine particles are obtained, the combustion temperature is high, and the number of core particles of silica and titanium oxide is increased, whereby the coalescence growth of the complex oxide fine particles is promoted and the particle diameter is 10 to 10. 300n
m, titanium oxide having a specific surface area of 10 to 100 m ² / g
~ 99% by weight of silica-titanium oxide spherical composite oxide fine particles are obtained, preferably further subjected to a hydrophobic treatment,
Addition to the toner provides the advantage that a developer having excellent fluidity and cleaning properties, and having a uniform charge amount and a stable charge can be obtained.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Susumu Ueno             2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu             Gakuin Co., Ltd. Gunma Office F term (reference) 2H005 AA08 AB02 CA26 CB07 CB13                       EA05 EA10                 4G072 AA37 BB05 DD05 DD06 GG03                       HH28 JJ44 JJ45 JJ46 JJ47                       MM01 RR03 RR11 RR30 TT01                       TT05 UU30

Claims (5)

[Claims] 1. A siloxane and an organotitanium compound are obtained by spray combustion in a flame and have a particle size of 10 to 300 nm,
Specific surface area is 10 to 100 m ² / g, titanium oxide is 1 to 9
An electrostatic charge image developer containing amorphous spherical silica / titanium oxide composite oxide particles in an amount of 9% by weight. 2. The electrostatic image developer according to claim 1, wherein the composite oxide fine particles are substantially free of chlorine. 3. The electrostatic image developer according to claim 1, wherein the organic titanium compound is a tetraalkoxy titanium compound, a titanium acylate compound, an alkyl titanium compound or a titanium chelate compound. 4. The composite oxide fine particles are produced by spraying siloxane and an organotitanium compound at the same time and oxidatively burning in a flame. At that time, the siloxane, the organotitanium compound, a supporting gas, and a combustion-supporting gas are supplied to the burner. The electrostatic image developer according to claim 1, 2 or 3, wherein the adiabatic flame temperature of combustion of siloxane, an organotitanium compound, and an auxiliary combustion gas is 1,650 ° C or higher and 4,000 ° C or lower on a gas basis. 5. Complex oxide fine particles on the surface of the following formula (1): (In the formula, R ¹ , R ² and R ³ are the same or different from each other and represent an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, x,
y and z are integers of 0 to 3, and x + y + z = 1 to 3. 5. The electrostatic image developer according to any one of claims 1 to 4, which is a hydrophobized fine particle into which a unit represented by the formula (4) is introduced.