JPH0534968A - Toner composition for electrophotographic development - Google Patents

Abstract

PURPOSE:To provide a toner compsn. for electrophotographic development having improved environmental stability. of a charged state without deteriorating the flowability of the toner. CONSTITUTION:Toner matrix particles are mixed with fine metal oxide particles of <=1.0mum average particle diameter with a complex formed on the surfaces as an additive to obtain a toner compsn. The complex is produced by bringing at least one kind of ligand selected among a mono- or polycyclic arom. diol deriv., a hydroxycarboxylic acid deriv. and a dicarboxylic acid deriv. into coordination with an atom of the metal of the metal oxide particles such as silicon dioxide as a central atom.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a toner for electrophotographic development having improved fluidity and environmental stability.

[0002]

2. Description of the Related Art Toners for electrophotographic development have two major problems: chargeability control and powder flowability.
In order to impart fluidity to the toner, it is usual to use a fine powder such as silicon dioxide as an external additive, but in that case, the environmental dependence of the charge amount of the toner is greatly changed.
Generally, in a high temperature and high humidity environment, the charge amount becomes low and the image density becomes too high. In a low temperature and low humidity environment, the charge amount becomes too high, and the image density becomes low. That is, the conventional external additives such as silicon dioxide fine particles have a problem that the image density changes due to changes in the environment.

On the other hand, the hydroxyl groups present on the surface thereof are reacted with various coupling agents such as a silane coupling agent, alcohol, etc. to perform a hydrophobic treatment,
It has been proposed to reduce the environmental dependence by making it hydrophobic, but it was poorly effective. In addition, many silane coupling agents have self-aggregating properties, and even if fine powder is used as the raw material, free silane coupling agents aggregate after the completion of the reaction in the drying process, etc. It also had a manufacturing problem that it was difficult to obtain a powder having a particle size range sufficient to impart In addition, JP-A-6
Japanese Patent Laid-Open No. 1-7846 discloses that fine particles of silicon dioxide silica or aluminum oxide having a carboxylic acid adsorbed on the surface are used as an external additive, but in this case, the carboxylic acid is simply adsorbed. However, there is a problem in that the durability is insufficient, and that the carboxyl groups present on the surface largely depend on the environment, and the environmental stability is insufficient.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a toner composition for electrophotographic development which has improved environmental stability of charging without impairing the fluidity of the toner. Another object of the present invention is to provide an additive which, unlike a silane coupling agent or the like, does not generate an aggregate and is extremely close to the original particle size and imparts fluidity and charge controllability to a toner. To do.

[0005]

Means for Solving the Problems As a result of studies by the present inventors, the above object can be achieved by using metal oxide fine particles having a complex formed on the surface of a specific compound as an additive. The present invention has been found and the present invention has been completed. That is, the present invention provides a toner composition for electrophotographic development comprising toner mother particles and metal oxide fine particles having an average particle size of 1.0 μm or less, wherein the metal oxide fine particles have a monocyclic ring with the metal atom as a central atom. Alternatively, the metal oxide fine particles have a complex structure in which at least one ligand selected from polycyclic aromatic diol derivatives, hydroxycarboxylic acid derivatives or dicarboxylic acid derivatives is coordinated.

The present invention will be described in detail below. Metal oxide fine particles added as an additive in the present invention,
It is necessary that the particle size is 1.0 μm or less. When the particle size is larger than 1.0 μm, the effect of imparting fluidity cannot be obtained. As the metal oxide, any one can be used as long as the ligand described below can be coordinated,
For example, titanium dioxide, silicon dioxide, aluminum oxide, tin dioxide, manganese dioxide, iron oxide, ferrosoferric oxide, magnesium oxide, zirconium oxide, zinc oxide and the like can be mentioned. Among these, silicon dioxide, especially,
Highly pure silicon dioxide obtained by gas phase synthesis is preferred.

A monocyclic or polycyclic aromatic diol derivative to be bonded as a ligand to the surface of the metal oxide fine particles,
Examples of the hydroxycarboxylic acid derivative or dicarboxylic acid derivative include catechol, salicylic acid, and hydroxy-1-.
Naphthoic acid, hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid, mandelic acid, benzylic acid, 2,
Examples thereof include 2'-dihydroxybiphenyl and derivatives in which these alkyl groups and aryl groups are substituted. The treating agent can be used in the range of 0.01 to 5 parts by weight. It is preferably used in the range of 0.1 to 2 parts by weight. A monocyclic or polycyclic aromatic diol,
In order to bind the hydroxycarboxylic acid or dicarboxylic acid to the surface of the metal oxide fine particles as a ligand, heating or catalytic reaction can be carried out. Preferably, a method of reacting in the presence of metal alkoxide is adopted. In the present invention, since a specific compound is bound as a ligand to the surface of the metal oxide fine particles, a complex is likely to be uniformly formed on the surface and the aggregation of the fine particles is unlikely to occur.
Therefore, there is an effect that the fine particles are stable for a long period of time.

Toner mother particles to which the above additives are added are
There is no particular limitation, and any known colorant and binder resin can be used. The binder resin used for the toner mother particles, styrene, styrenes such as chlorostyrene, ethylene, propylene, butylene, monoolefins such as isoprene, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, Octyl acrylate,
Phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, α-methylene aliphatic monocarboxylic acid ester of methacrylate dodecyl nad, vinyl ether such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, vinyl methyl ketone, vinyl hexyl Examples thereof include homopolymers and copolymers of vinyl ketones such as ketones and vinyl isopropenyl ketone. Especially as a typical binder resin,
Polystyrene, styrene-acrylic acid alkyl ester copolymer, styrene-methacrylic acid alkyl ester copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene. be able to.

Further, as the colorant for the toner mother particles, carbon black, graphite, nigrosine, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue,
Malachite Green Oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment Red 48: 1,
C. I. Pigment Red 57: 1, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 1
2, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3 and the like can be illustrated as a typical example. When used as a one-component magnetic toner, it can be obtained by adding a magnetic component.

In these toner mother particles, if desired, other known charge control agents such as metal salicylate, nigrosine and quaternary ammonium salts, and offset preventive agents such as low molecular weight propylene, low molecular weight polyethylene and wax can be used. You may contain an additive. Further, additives such as cleaning aids or transfer aids such as polystyrene fine particles, polymethylmethacrylate fine particles, and polyvinylidene fluoride fine particles may be added. The toner mother particles are the above resin,
It is obtained by adding a colorant and, if necessary, an internal additive, melt-kneading, and pulverizing and classifying to obtain fine particles having an average particle diameter of 5 to 20 μm. The toner of the present invention is obtained by mixing the above-mentioned fine particles and the treated oxidized fine powder with a V blender, a Henschel mixer, a hybridizer or the like.

When the above toner composition is used as a developer, it is used as a one-component developer comprising only the toner composition of the present invention or as a two-component developer by mixing with a carrier. As such a carrier, a resin-coated carrier, iron powder, ferrite, iron oxide powder, magnetic powder dispersion type carrier or the like can be used.

[0012]

EXAMPLES The present invention will be described below with reference to examples. All "parts" in the examples mean parts by weight. Example 1 The following components were kneaded, pulverized and classified by a conventional method to prepare toner particles having an average particle size of 12 μm. Styrene-acrylic resin (Sanyo Kasei, trade name: SBM730) 92 parts Carbon black (Mitsubishi Kasei, trade name: # 44) 6 parts Charge control agent (Hodogaya Chemical Co., trade name: Spiron Black TRH) 2 parts

Further, 7.7 g of a sodium methylate methanol solution was further diluted with 300 ml of methanol, and this solution was dried for one day at 200 ° C. in a dryer to obtain silicon dioxide (Aerosil # 200, manufactured by Nippon Aerosil Co., Ltd.). 13.5 g was added, and 100 ml of a methanol solution in which 6.6 g of catechol was dissolved was added dropwise while stirring. Then, the temperature of the mixture was kept at 80 ° C. for 2 hours to complete the reaction. After the reaction product was taken out, it was ground in a mortar to obtain treated fine particles having an average particle diameter of 0.02 μm. In addition,
The reaction was carried out under a nitrogen atmosphere, and the yield was 78% as silicon dioxide. It is presumed that the surface of the silicon dioxide fine particles has the following structure by the above reaction.

[0014]

[Chemical 1]

Treated fine particles obtained as described above 1.
A toner was prepared by adding 0 parts to 100 parts of toner particles using a Henschel mixer. Toner 3 obtained
Iron powder carrier (made by Powder Tech Co., Ltd.) 10
A developer was obtained by mixing 0 parts.

Comparative Example 1 A toner was prepared in the same manner except that the treated fine particles were not added to obtain a developer.

Comparative Example 2 A toner was prepared in the same manner as in Example 1 except that silicon dioxide (Aerosil # 200, manufactured by Nippon Aerosil Co., Ltd.) which was not surface-treated was used as the treated fine particles.
A developer is obtained.

Example 2 Treated fine particles were obtained in the same manner as in Example 1 except that 8.3 g of salicylic acid was used in place of 6.6 g of catechol. The surface of the treated fine particles is presumed to have the following structure.

[0019]

[Chemical 2] A toner was prepared in the same manner using this additive to obtain a developer.

The developers of Examples 1 and 2 and Comparative Examples 1 and 2 were used in a copying machine (FX5990, manufactured by Fuji Xerox).
When evaluated by putting it in, the results shown in Table 1 below were obtained.

[0021]

[Table 1]

Note) Low temperature and low humidity means 10 ° C., 15% RH
High temperature and high humidity means 30 ° C. and 85% RH. The image density maintainability was determined by determining whether or not there was a decrease in density after continuous copying of 100 sheets, and was used as an index of toner fluidity. ○ is good, ×
Means bad.

As is clear from Table 1, when silicon dioxide fine particles are added as an additive, fluidity is imparted to the toner and the toner is continuously replenished in the developing machine, so that the image density is not reduced due to the toner shortage. Absent. However, the toner charge amount is largely dependent on the environment, and there is a concentration fluctuation due to it. On the other hand, in the toner using the surface-treated silicon dioxide fine particles according to the present invention,
At the same time that the fluidity is imparted, the environmental dependence of the toner charge amount is eliminated, so that the density fluctuation is improved.

[0024]

As described above, the electrophotographic developing toner composition of the present invention comprises a monocyclic or polycyclic aromatic diol,
Since the metal oxide fine particles on the surface of which a metal complex having a hydroxycarboxylic acid or a dicarboxylic acid as a ligand is formed are used as an external additive, the fluidity of the toner is improved and the environmental stability of charging is also improved. In addition, unlike the silane coupling agent and the like, it does not generate aggregates.
Therefore, when development is performed using the toner composition for electrophotographic development of the present invention, a copy having good environment resistance and good image quality without reduction in density can be obtained.

Claims (1)

1. A toner composition for electrophotographic development comprising toner mother particles and metal oxide fine particles having an average particle size of 1.0 μm or less, wherein the metal oxide fine particles are mainly composed of metal atoms. A metal oxide fine particle having a complex structure in which at least one kind of ligand selected from a monocyclic or polycyclic aromatic diol derivative, a hydroxycarboxylic acid derivative or a dicarboxylic acid derivative is coordinated as an atom. A featured toner composition for electrophotographic development.