JPH10268552A - Electrostatic image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain electrostatic image developing toner capable of preventing the occurrence of smearing, offset and filming at a copying operation and which is excellent in the flowability and electrostatic chargeability by externally adding inorganic particles of a specific average primary particle size and hydrophobed inorganic particles of a specific average primary particle size. SOLUTION: The electrostatic image developing toner is constituted of at least polyethylene wax, polypropylene wax, binder resin and coloring agent, and the inorganic particles A having the average primary particle size of 0.03 to 3 μm and the hydrophobic inorganic particles B having the average primary particle size of 0.005 to 0.02 μm are externally added. Thus, the electrostatic image developing toner cable of preventing the occurrence of smearing, offset and filming on a copied image and which is excellent in the flowability and electrostatic chargeability is obtained by externally adding the inorganic particles A and the inorganic particles B, even in the case that the polyethylene wax and the polypropylene wax are simultaneously incorporated in the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used for developing an electrostatic image formed on a photosensitive member in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art As a fixing method for an image forming apparatus such as an electrophotographic apparatus, a pressure fixing method, a non-contact heat fixing method such as flash fixing and open fixing, and a contact heat fixing method such as a heat roll fixing method are employed. I have. In particular, the contact heat fixing method can be operated at a higher speed than the pressure fixing method, has higher thermal efficiency than the non-contact heat fixing method, can use a relatively low-temperature heat source, and can reduce the size of the apparatus and save energy. This is the most widespread fixing method because it can be achieved.

In recent years, such a contact heating fixing type electrophotographic apparatus has been required to have higher speed and energy saving. Therefore, low-temperature fixing characteristics are required for the toner. If low-temperature fixing is realized, not only energy saving of the electrophotographic apparatus can be achieved, but also warm-up time can be shortened, and more comfortable operability can be obtained.

In such a contact heating fixing system,
For example, when fixing by the hot roll fixing method, a part of the toner constituting the image is transferred to the surface of the hot roll, which is transferred again to the next transfer paper to cause an offset phenomenon that contaminates the image. Had become. As a technique for preventing the offset phenomenon, for example, a technique of adding a polypropylene wax to a toner as an offset preventing agent (release agent) is known (for example, Japanese Patent Application Laid-Open No. 49-65231).

In recent years, as the copying speed of electrophotography has been increased and the functions thereof have been increased, a copying machine equipped with an automatic document feeder and a duplex copying machine has become a standard. When the original is fed by these devices, or in the second copying process of backside copying or multicolor copying, the surface of the copied image is rubbed by a roller at the time of paper feeding, causing problems such as blurring and dirt on the image. I have. A similar phenomenon is observed when a plurality of copied images are temporarily stored in a copying machine by superimposing them one by one by a paper feed roller for the second copy, and the image quality is degraded. It is said that toner having such a problem has poor smear property. As a method for improving the smearing property, it is known that the addition of polyethylene wax to a toner is effective (for example, JP-A-4-313762).

However, when the above-mentioned polypropylene wax and polyethylene wax are used in combination to simultaneously improve the offset property and the smear property, a new problem occurs that filming occurs and the fluidity and chargeability of the toner decrease. doing.

On the other hand, in an image forming apparatus such as a copying machine or a printer, an electrostatic charge image is formed on the surface of a photoreceptor, a developer is supplied to the photoreceptor from a developing device, and the electrostatic charge formed on the photoreceptor is formed. Develop the image to form a toner image on the photoreceptor,
After transferring the toner image onto a transfer material such as recording paper, a cleaning blade or the like is pressed against the surface of the photoconductor to remove toner and the like remaining on the surface of the photoconductor. When an image is formed using such an apparatus, filming also occurs due to toner components and fillers such as talc and calcium carbonate generated from a transfer material such as recording paper adhere to the surface of the photoconductor. There is a problem of doing.

Various proposals have been made to improve the photosensitive layer of the photoreceptor. However, filming of fillers, toner components and the like adhering to the surface of the photoreceptor cannot be sufficiently suppressed. It is not at present.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner for developing an electrostatic image, which prevents smear, offset and filming from occurring during copying, and is excellent in fluidity and chargeability of the toner. I do.

[0010]

The present invention relates to a toner for developing an electrostatic image comprising at least a polyethylene wax, a polypropylene wax, a binder resin and a coloring agent, wherein the inorganic fine particles A have an average primary particle diameter of 0.03 to 3 μm. And an average primary particle size subjected to the hydrophobic treatment is 0.005 to 0.0.
The present invention relates to a toner for developing an electrostatic image, wherein inorganic fine particles B of 2 μm are externally added.

Even when polyethylene wax and polypropylene wax are simultaneously contained in the toner, smear, offset and filming do not occur on a copied image by externally adding the inorganic fine particles A and inorganic fine particles B, and It has become possible to provide an electrostatic image developing toner having excellent fluidity and chargeability.

The toner of the present invention comprises at least a polyethylene wax, a polypropylene wax, a binder resin and a colorant.

The polyethylene wax used in the present invention has a softening point of 100 to 150 ° C., preferably 120 to 140 ° C.
Use one in the range of ° C. If the softening point of the polyethylene wax is lower than 100 ° C., the heat resistance is poor and filming is liable to occur. Either high-density or low-density polyethylene wax may be used, but high-density polyethylene is preferably used from the viewpoint of improving smearing properties.

As the polyethylene wax, a vinyl monomer graft polyethylene may be used. This is a polyethylene obtained by graft polymerization of a vinyl monomer, which is obtained by thermal decomposition of high-pressure polyethylene, a high-pressure polymerized polyethylene wax obtained by radical polymerization of ethylene at high pressure, and further ethylene or ethylene and propylene, Α such as 1-butene, 1-hexene, 4-methyl-1-pentene, 1-decene
-It is obtained by medium / low pressure polymerization of an olefin with a transition metal compound catalyst.

The vinyl-based monomer-grafted polyethylene wax not only has excellent compatibility with a binder resin such as a styrene-based polymer, but also has various additives, such as a pigment and a dye, a charge control agent, and a plasticizer. Excellent in solubility and affinity. Therefore, it also has the effect of increasing the dispersibility in these binder resins, increasing the physical uniformity of the toner such as charge controllability, and improving the performance as a developer.

In the present invention, the polyethylene wax is preferably used in an amount of 0.1 to 100 parts by weight of the binder resin.
5 parts by weight, more preferably 0.3 to 4 parts by weight is suitable. If the blending amount of the polyethylene wax is less than this, the smear preventing effect is insufficient, and if it is too large, filming tends to occur and the fluidity of the toner tends to decrease.

The polypropylene wax used in the present invention has a softening point of 130 to 160 ° C., preferably 145 to 160 ° C.
155 ° C. is suitable. When the softening point is lower than 130 ° C., not only the heat resistance decreases, but also filming easily occurs. On the other hand, when the temperature is higher than 160 ° C., the offset property decreases. High-temperature offset can be effectively prevented by using a polypropylene wax having a softening point higher than the softening point of the polyethylene wax used in combination, preferably having a difference of 25 ° C. or less.

The polypropylene wax is used in an amount of 2.5 to 7 parts by weight, preferably 3 to 100 parts by weight of the binder resin.
It is preferable to mix up to 6 parts by weight. If the blending amount of the polypropylene wax is less than this, the offset property is reduced, and if it is too large, the fluidity of the toner is poor and filming is liable to occur.

The total amount of polyethylene wax and polypropylene wax added is 2 to 10 parts by weight, more preferably 3 to 8 parts by weight, based on 100 parts by weight of the binder resin. If the total amount of the polyethylene wax and the polypropylene wax is less than this, the offset property is reduced, and if it is too large, the fluidity of the toner is poor and filming is liable to occur.

Among them, the addition weight ratio of the polypropylene wax to the polyethylene wax is 10: 1 to 1:10.
And preferably 10: 1 to 1: 2, more preferably 10: 1 to 3: 4. If the weight ratio of the polyethylene wax is less than this, filming is liable to occur, and if it is too large, the offset property is liable to decrease.

In the present invention, waxes other than polypropylene wax and polyethylene wax, for example, carnauba wax, sasol wax, rice wax and the like may be used in combination as long as the effects of the present invention are not impaired.

As the binder resin which can be used in the present invention, styrene copolymer resins, polyester resins, epoxy resins and the like which have been conventionally used as binder resins for toners can be used. In general, the chargeability of the toner can be adjusted by any of positive or negative charge control agents described below.
In the production of a positively chargeable toner, a styrene copolymer resin is used, and in the production of a negatively chargeable toner, a polyester resin, a styrene copolymer resin, an epoxy resin, or the like is often used. Styrene-based copolymer resins are effective in producing positively and negatively chargeable toners.

These binder resins have a number average molecular weight distribution measured by gel permeation chromatography in a range of at least 2,000 to 10,000,
More preferably, the weight average molecular weight / number average molecular weight is in the range of 20 to 90, and more preferably 25 to 80.

When the number average molecular weight is less than 2,000, the heat resistance is lowered and offset tends to occur, and the number average molecular weight is reduced to 10,000.
Exceeding the range lowers the fixing strength. The weight average molecular weight /
When the ratio of the number average molecular weight is less than 20, the offset property is lowered, and when it is more than 90, the fixing strength is apt to be deteriorated.

Among the binder resins described above, styrene copolymer resins are particularly preferred because they can achieve the object of the present invention more effectively. Examples of the styrene monomer constituting the styrene copolymer resin include styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, p-tert-butylstyrene, and p-chlorostyrene. Its derivatives can be used.

Monomers to be copolymerized with the styrene monomer include methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, methacrylic acid n-pentyl, isopentyl methacrylate, neopentyl methacrylate, 3-methacrylic acid
(Methyl) butyl, hexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate,
Methacrylic acid alkyl esters such as undecyl methacrylate and dodecyl methacrylate; methyl acrylate,
N-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, neopentyl acrylate, 3-acrylic acid
(Methyl) butyl, hexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate and dodecyl acrylate; alkyl acrylates; unsaturated such as acrylic acid, methacrylic acid, itaconic acid and maleic acid Carboxylic acid; using vinyl monomers such as acrylonitrile, maleic ester, itaconic ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether be able to. Preferred are methacrylic acid alkyl esters (alkyl group having 1 to 17 carbon atoms) and acrylic acid alkyl esters (alkyl group having 1 to 17 carbon atoms).

An acid value may be given to the binder resin in order to improve the dispersibility of the polyethylene wax, the polypropylene wax, the colorant and the like. For example, when using a styrene-based copolymer resin as the binder resin, the acid value is controlled by adjusting the amount of the unsaturated carboxylic acid such as (meth) acrylic acid to be contained in the styrene-based copolymer resin, and The value is from 1 to 30 KOH mg / g, preferably from 3 to
10 KOH mg / g is appropriate.

The colorant used in the present invention is not particularly limited, and a colorant conventionally used in electrophotography can be used, and examples thereof include the following. As the black pigment, carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, ferrite, magnetite and the like can be used. As yellow pigments, yellow lead, zinc yellow, cadmium yellow, yellow iron oxide,
Mineral fast yellow, nickel titanium yellow,
Navels Yellow, Naphthol Yellow S, Banza Yellow G, Banza Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake and the like can be used.

Examples of the red pigment include red lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indaslen brilliant orange RK, benzidine orange G, indaslen brilliant orange GK, red bengala, cadmium red, lead red, permanent Red 4R, Risor Red,
Pyrazolone red, watching red, lake red C, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake,
Brilliant Carmine 3B, permanent orange GT
R, Vulcan Fast Orange GG, Permanent Red F4RH, Permanent Carmine FB and the like can be used. Blue pigments include navy blue, cobalt blue, alkaline blue lake, Victoria blue lake,
Phthalocyanine blue or the like can be used. In addition, although the addition amount of these coloring agents is not particularly limited,
Usually, 1 to 100 parts by weight of resin in toner
20 parts by weight, preferably 3 to 15 parts by weight.

The toner of the present invention may contain other additives, and may appropriately contain a charge controlling agent, magnetic powder and the like.

As the charge control agent, a positive charge control agent can be used when the positive charge control of the toner is desired, and a negative charge control agent is used when the negative charge control of the toner is desired. Examples of the positive charge control agent that can be used in the present invention include a nigrosine dye, a triphenylmethane compound, a quaternary ammonium salt compound, and the like. Examples of triphenylmethane compounds include, for example, JP-A-51-11455, JP-A-59-100457, and JP-A-61-12495.
Compounds described in, for example, Japanese Patent Publication No. 5 can be used. As the quaternary ammonium salt compound, for example, compounds described in JP-A-4-70849 or the like can be used. Salicylic acid metal complex as a negative charge control agent,
Examples include gold-containing azo dyes, calixarene compounds, and boron-containing compounds. The amount of the binder resin 10
0.1 to 10 parts by weight is preferably based on 0 parts by weight.

As the magnetic powder, ferrite, magnetite and iron powder can be used alone or as a mixture. The inclusion of the magnetic powder can more effectively prevent filming, scattering of toner due to magnetic force, and erosion. Further, the smear property and the offset property are further improved.

The BET specific surface area is ² to 15 m ² in order to prevent a decrease in chargeability due to poor dispersion of the magnetic powder in the toner.
/ G, preferably 5 to 12 m ² / g.

The amount of the magnetic powder used in the present invention is 20 parts by weight or less, preferably 2 to 10 parts by weight, based on 100 parts by weight of the binder resin. If the amount is more than 20 parts by weight, the image density is reduced due to a decrease in developability.

The toner for developing an electrostatic image of the present invention can be easily produced by, for example, a known kneading and pulverizing method, and at least a binder resin, a coloring agent, polyethylene wax and polypropylene wax, and if necessary, other The mixture comprising the additives is kneaded by a kneading extruder, and the kneaded material is cooled and solidified, then pulverized and classified to obtain toner particles having a volume average particle size of 5 to 14 μm, preferably 6 to 12 μm. It is obtained by externally adding inorganic fine particles A and B. The external addition is to add the toner particles so as to be present on the surface of the toner particles, and specifically means to add the toner particles after the toner particles are once prepared. In the pulverizing step, the material may be roughly pulverized by a pulverizer such as a feather mill to an average particle diameter of 2 mm or less, and then finely pulverized by a mechanical pulverizer to a desired particle diameter.

Examples of the inorganic fine particles A include silica fine particles, metal zirconate (for example, strontium) fine particles, metal titanate (for example, strontium) fine particles, titanium dioxide (titania) fine particles, ferrite fine particles, and magnetite fine particles. These can be easily obtained by a known method, for example, a gas phase method, a wet method, or the like.

The inorganic fine particles A have an average primary particle size of 0.0
One having a range of 3 to 3 μm is used. Average primary particle size is 0.0
If the material is smaller than 3 μm or larger than 3 μm, the photoconductor cannot be sufficiently polished, and the filming of the toner component or the like on the surface of the photoconductor cannot be sufficiently suppressed. The preferred average primary particle size is from 0.03 to 2 μm. Preferred inorganic fine particles A are silica fine particles having an average primary particle diameter of 0.03 to 0.05 μm obtained by a gas phase method or silica fine particles having an average primary particle diameter of 0.1 to 2 μm obtained by a wet method.

Further, in order to suppress the decrease in the chargeability of the toner due to the addition of the inorganic fine particles A, the surface of the inorganic fine particles A is treated with at least one type of surface treatment agent selected from aminosilane coupling agents and aminosilicone oils. In order to improve the fluidity and environmental stability of the developer, the inorganic fine particles A may be further subjected to a surface treatment with a hydrophobizing agent described later.

Examples of such an amino-based surface treating agent include γ-aminopropyltriethoxysilane,
Aminosilane coupling agents such as N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-anilinopropyltrimethoxysilane Can be As aminosilicone oils, KF369, KF383, KF393, KF85 manufactured by Shin-Etsu Chemical Co., Ltd.
7, KF860, KF861, KF862, KF86
4, KF865 and the like.

In the case of treating with an amino-based surface treating agent as described above, the surface treating agent is treated with 1 to 20 parts by weight, preferably 2 to 15 parts by weight, based on 100 parts by weight of the inorganic fine particles A. When the amount is more than 20 parts by weight, the inorganic fine particles A are easily aggregated. When the amount is less than 1 part by weight, the effect of the above-mentioned surface treating agent becomes insufficient. The treatment can be performed in the same manner as in the hydrophobic treatment described below. The inorganic fine particles A may be subjected to a hydrophobizing treatment with a hydrophobizing agent described below. In this case, the inorganic fine particles A are treated so that the degree of hydrophobicity is 30 or more, preferably 30 to 90.

When externally adding the inorganic fine particles A, if the addition amount is small, the photoreceptor cannot be sufficiently polished, and a filler such as talc and calcium carbonate or a toner component (particularly polyethylene While (wax) can not sufficiently suppress filming,
When the amount of addition increases, the chargeability of the toner decreases. Therefore, the amount of addition to the toner is 0.1 to 5% by weight, preferably 0.1 to 2% by weight, more preferably 0.2 to 1% by weight.
So that

In addition to the inorganic fine particles A, as the inorganic fine particles B to be externally added, inorganic fine particles of the same type as the inorganic fine particles A can be used, and the hydrophobic primary particles having an average primary particle diameter of 0.0 are used.
Those having a range of 0.05 to 0.02 μm are used. The inorganic fine particles B are used in order to improve the fluidity of the developer by adding the inorganic fine particles B and to enhance the environmental resistance and the chargeability of the developer. Also, the use of the inorganic fine particles B having an average primary particle size of not more than 0.02 μm is preferable if the average primary particle size is larger than 0.02 μm. The reason for this is that it is not possible to impart sufficient fluidity to the toner without using the toner particles. Environmental stability of the toner is likely to be reduced. Preferably, the average primary particle size is 0.007 to 0.017 μm.
The inorganic fine particles B in the range of m are used.

The inorganic fine particles B used in the present invention have been surface-treated with a hydrophobizing agent and have a hydrophobicity of 30.
%, Preferably 30 to 90%. By using the inorganic fine particles subjected to the hydrophobic treatment in this way, it is possible to prevent the toner charge amount from decreasing even at high temperature and high humidity. Further, the inorganic fine particles B are preferably treated with the above-mentioned amino-based surface treating agent together with a hydrophobizing agent in order to improve the positive chargeability.

As a hydrophobizing agent for surface-treating the inorganic fine particles, a silane coupling agent, a titanate coupling agent, silicone oil, silicone varnish and the like can be used. As the silane coupling agent, for example,
Hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, Dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n
-Butyltrimethoxysilane, n-hexylmethoxysilane, n-octyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltri Methoxysilane, vinyltriacetoxysilane and the like can be used, and as the silicone oil, for example, dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane and the like can be used.

In the surface treatment of the inorganic fine particles with the above-mentioned hydrophobizing agent, for example, the hydrophobizing agent is diluted with a solvent, the above-mentioned diluent is added to the inorganic fine particles and mixed, the mixture is heated and dried, and then crushed. And a wet method in which inorganic fine particles are dispersed in an aqueous system to form a slurry, a hydrophobizing agent is added, mixed, heated and dried, and then crushed.

When externally adding such inorganic fine particles B, if the amount of addition is small, the fluidity of the developer cannot be sufficiently improved, while if the amount of addition is too large, toner Since the chargeability is reduced and the toner is scattered or fog is generated on the formed image, the amount of the inorganic fine particles B added to the toner is 0.05 to 5%.
The content is 1.0% by weight, preferably 0.1 to 0.5% by weight.

Further, a cleaning aid may be externally added to the toner of the present invention together with the inorganic fine particles A and B.

Examples of the cleaning aid include styrene-based, acrylic-based, methacryl-based, benzoguanamine, silicone, Teflon, and the like, which are granulated by a wet polymerization method such as emulsion polymerization, soap-free emulsion polymerization, non-aqueous dispersion polymerization, or a gas phase method. Various organic fine particles such as polyethylene and polypropylene can be used alone or in combination. The addition amount is usually 0.0 to 100 parts by weight of the binder resin.
1 to 1 part by weight.

The toner for developing an electrostatic image of the present invention obtained as described above is a one-component developer using no carrier,
Although any of the two-component developers used with the carrier can be used, it is preferable to use the two-component developer. As the carrier used with the toner of the present invention, known carriers can be used, for example, iron powder, a carrier composed of magnetic particles such as ferrite, a coated carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, Alternatively, any of a dispersion type carrier obtained by dispersing a magnetic fine powder in a binder resin can be used.
Such carriers have a volume average particle size of 15 to 10
Those having a thickness of 0 μm, preferably 20 to 80 μm are suitable.

When the toner of the present invention is used as a positively chargeable toner, a preferable carrier is a chargeable toner.
That is, the carrier has a negatively charged resin on the surface.
Examples of such resins include polyester resins, polyolefin resins such as polyethylene, tetrafluoroethylene, vinylidene fluoride, homopolymers of fluorine-containing vinyl monomers, and copolymers with other vinyl monomers. And the like. Particularly preferred is a carrier on which the above-mentioned negatively chargeable resin coating layer is formed, or a carrier obtained by dispersing magnetic fine powder in the above negatively chargeable resin, from the viewpoint of chargeability in combination with the toner of the present invention. .

When the toner of the present invention is used as a negatively chargeable toner, a carrier having a positively chargeable resin on its surface is preferable. Such resins include acrylic resins,
Styrene-acrylic resin, silicone resin and the like can be mentioned. The present invention is described in more detail by the following examples.

[0052]

EXAMPLES In this example, as the inorganic fine particles A, any one of the following types of inorganic fine particles was used. (Silica A) The average primary particle size obtained by the gas phase method is 0.
03-μm silica was mixed and stirred in an aqueous system, and n-octyltrimethoxysilane was added so that it would be 20% by weight of silica and γ-aminopropyltriethoxysilane would be 5% by weight in terms of solid content. The mixture was dried and crushed to obtain silica A having a hydrophobicity of 75%.

(Silica B) In the same manner as for silica A, silica B having an average primary particle size of 0.04 μm was used to obtain silica B having a hydrophobicity of 80%.

(Silica C) In the same manner as for silica A, silica C having a hydrophobicity of 75% was obtained using silica having an average primary particle size of 1 μm.

(Silica D) Silica obtained by a wet method having an average primary particle size of 1.0 μm was mixed with n-
Hexylmethoxysilane was added and mixed so as to be 15% by weight of silica in terms of solid content, and this was dried and crushed to obtain Silica D having a hydrophobicity of 60%.

(Titania A) Rutile-type titania having an average primary particle diameter of 0.035 μm obtained by a gas phase method was mixed and stirred in an aqueous system while n-hexylmethoxysilane was 15% by weight of the titania in terms of solid content. Add and mix so that
This was dried and crushed to obtain titania A having a hydrophobicity of 60%.

(Titania B) Titania having an average primary particle size of 1 μm obtained by a wet method was used. (Ferrite A) Ferrite having an average primary particle size of 0.5 μm was used. (Magnetite A) Magnetite having an average primary particle size of 1.5 μm was used. (Strontium titanate A) Strontium titanate having an average primary particle size of 2 μm was used. (Strontium Zirconate A) Strontium zirconate having an average primary particle size of 3 μm was used.

As for the inorganic fine particles B, hydrophobic silica having an average primary particle size of 0.016 μm (R972 manufactured by Nippon Aerosil Co., Ltd.) and hydrophobic silica having an average primary particle size of 0.012 μm (Nippon Aerosil Co., Ltd.) R974), hydrophobic silica having an average primary particle size of 0.009 μm (manufactured by Nippon Aerosil Co., Ltd .; R976) or an average primary particle size of 0.012 μm
One of the hydrophobic silicas (RA200HS, manufactured by Nippon Aerosil Co., Ltd.) treated with the amino coupling agent that has become the target is used.

Example 1 100 parts by weight of a thermoplastic styrene-acrylic resin (styrene-butyl acrylate-butyl methacrylate-methacrylic acid copolymer (monomer weight ratio = 7: 1.4: 1.4: 0. 2, acid value 6.5 KOHmg / g), number average molecular weight = 4,500, weight average molecular weight / number average molecular weight = 65) 4 parts by weight of polypropylene wax (softening point 145 ° C., acid value 0) (Viscol 660P,・ 2 parts by weight of polyethylene wax (softening point 140 ° C.) (high wax 800P, manufactured by Mitsui Petrochemicals) ・ 10 parts by weight of carbon black (Mogal L, manufactured by Cabot Corporation) ・ 5.0 parts by weight of nigrosine dye (Nigrosine base EX, manufactured by Orient Chemical Co., Ltd.)-Quaternary ammonium salt 0.5 parts by weight (P-53, manufactured by Orient Chemical Co., Ltd.)-Magnetic powder (MFP-2, manufactured by TDK Corporation) 2 parts by weight or more Material using a Henschel mixer (capacity 75 liters) were mixed 3000rpm for 3 minutes. The mixture was continuously extruded and kneaded by a screw extrusion kneader (TEM50: manufactured by Toshiba Machine Co., Ltd.) under the conditions of a temperature of 120 ° C., a supply amount of 30 kg / hr, and a screw rotation speed of 150 rpm. Further, it was water-cooled on a belt cooler.

This kneaded material is subjected to a feather mill (2 mm mesh)
And coarsely pulverized. The coarsely crushed material is mechanically crushed (Krypton K
(TM-O type, manufactured by Kawasaki Heavy Industries, Ltd.)
Jet mill equipped with a natural air flow classifier (IDS-2
Cut the coarse powder with a mold
Further, fine powder was cut by a rotary rotor classifier (50 ATP classifier, manufactured by Hosokawa Micron), and the volume average particle size was 1
1 μm toner particles were obtained.

To the obtained toner particles, 0.5% by weight of silica A as inorganic fine particles A and 0.15% by weight of hydrophobic silica (Aerosil, R974) as inorganic fine particles B were added, and a Henschel mixer (75 liter capacity) was added. ) Using 1
The mixture was mixed and added at 000 rpm for 1 minute to obtain a toner.

Examples 2 to 17 and Comparative Examples 1 to 3 Toners were prepared in the same manner as in Example 1. However, the types and amounts of the polypropylene wax, the types and amounts of the polyethylene wax, and the types and amounts of the inorganic fine particles A and B are as shown in Tables 1 and 2.

The above Examples 1 to 17 and Comparative Examples 1 to 3
Was mixed with a binder-type carrier manufactured as follows at a weight mixing ratio (toner: carrier) of 5:95 to obtain a developer.

(Production Example of Binder Type Carrier) Ingredients: parts by weight ・ Polyester resin (manufactured by Kao Corporation: NE-1110) 100 ・ Inorganic magnetic powder (manufactured by TDK: MFP-2) 500 ・ Carbon black (manufactured by Mitsubishi Kasei Corporation) : MA # 8) 2 The above materials were sufficiently mixed and crushed with a Henschel mixer, and then the cylinder section was 180 ° C. and the cylinder head section was 17
The mixture was extruded and kneaded using an extrusion kneader set at 0 ° C. The kneaded product was cooled, coarsely pulverized, finely pulverized with a jet mill, and further classified using an air classifier to obtain a magnetic carrier having a volume average particle size of 55 μm.

The developer obtained by mixing with the binder type carrier was evaluated for the following items. (1) Smear property After copying using the above-mentioned developer and a copying machine (EP4050; manufactured by Minolta Co., Ltd.) and fixing it on copy paper, another unused copy paper is replaced with a previously obtained copy image. The unused copy paper was rubbed with the formed paper, and the degree of contamination of the unused copy paper was observed. The paper was ranked as follows. ：: Almost no stain was conspicuous; Δ: Slight stain was observed but no problem in practical use; ×: Stain was observed on all paper surfaces.

(2) Offset property When copying using the above copying machine modified so that the fixing temperature can be changed, the temperature of the fixing roller is raised to around 250 ° C., and the following ranking is made according to the temperature at which the offset occurs. ○: no offset occurs at 250 ° C .; Δ: no offset occurs below 250 ° C .; x: offset occurs below 230 ° C.

(3) Filming After continuously copying 50,000 sheets using a copying machine (EP4050; manufactured by Minolta Co., Ltd.), a halftone image was formed and the photosensitive member was observed. Was attached. ：: Neither image disturbance nor toner component adhesion to the photoreceptor. Δ: A part of the surface of the photoreceptor is slightly hazy, but there is no image disturbance. ×: The entire photoconductor is cloudy, and the image is further disturbed.

(4) Fluidity The apparent specific gravity (g / cc) of the toner used in the developer was measured with a powder tester (manufactured by Hosokawa Micron Corporation), and when the apparent specific gravity was 0.380 or more, 、, 0.3. 3
The case of 60 or more and less than 0.380 was evaluated as Δ, and the case of less than 0.36 was evaluated as x.

(5) Similarly, evaluation of fog filming was carried out by making 50,000 copies of each developer using a document having a black ratio of 6%, and then visually evaluating the formed image. ○, when fog was hardly observed, △ when slight fog was observed but no practical problem was indicated, and x when there was much fog.

The above evaluation results are shown together with the toner production conditions of Examples 1 to 17 and Comparative Examples 1 to 3 in Tables 1 and 2 below.

[0071]

[Table 1]

[0072]

[Table 2]

In this example, the average particle size and the degree of hydrophobicity were measured as follows. The average particle size of the carrier is
Using Coulter Multisizer (manufactured by Coulter), 2
The measurement was performed using an 80 μm aperture tube. The average particle size of the toner was measured using the same apparatus with a 100 μm aperture tube.

Regarding the degree of hydrophobicity, 0.2 g of a sample was collected in a 100 ml beaker based on the wetting characteristic measurement method by the Degussa method, and 50 ml of pure water was added.
Methanol was added below the liquid surface, and the point at which no sample was observed on the liquid surface was defined as the end point, and the degree of hydrophobicity was calculated from the required amount X of methanol by the following equation. Hydrophobicity = {X / (50 + X)} × 100

[0075]

According to the present invention, it is possible to prevent smearing and offset during copying, to prevent filming from occurring, and to provide a toner which does not cause a decrease in fluidity or chargeability of the toner.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Yoshihiro Mikuri, 2-3-3 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Hiroshi Fukao, Azuchi-cho, Chuo-ku, Osaka-shi, Osaka Osaka Metropolitan Building Minolta Co., Ltd. (72) Inventor Fumiko Nakazawa 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka

Claims (3)

[Claims] 1. An electrostatic image developing toner comprising at least a polyethylene wax, a polypropylene wax, a binder resin, and a colorant, wherein the inorganic fine particles A have an average primary particle diameter of 0.03 to 3 μm and an hydrophobically treated average particle. Inorganic fine particles B having a primary particle size of 0.005 to 0.02 μm
Is externally added to the toner for developing an electrostatic image. 2. The total addition amount of polyethylene wax and polypropylene wax is 2 to 10 parts by weight based on 100 parts by weight of a binder resin, and the addition weight ratio of polypropylene wax to polyethylene wax is 10: 1.
2. The electrostatic image developing toner according to claim 1, wherein the ratio is about 1:10. 3. A polypropylene wax having a softening point of 13
The electrostatic image according to claim 1, wherein the temperature is 0 to 160 ° C., the softening point of the polyethylene wax is 100 to 150 ° C., and the softening point of the polypropylene wax is higher than the softening point of the polyethylene wax. Development toner.