JP3042023B2 - Electrostatic image developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component or two-component electrostatic image developer for electrophotographic copying machines and printers. The developer of the present invention has stable fluidity and chargeability even under high stress, and can perform high-speed, high-quality copying.

[0002]

2. Description of the Related Art In order to obtain an image by an electrophotographic copying machine or a printer, first, the surface of a photoreceptor, which is an image carrier, is uniformly charged, and the surface is exposed based on a pattern corresponding to the image of a document. Alternatively, the contents of the output are drawn on the photoreceptor with light to form an electrostatic latent image. Next, the surface of the photosensitive member having the electrostatic latent image is developed (visualized) using a developing device, and the obtained toner image is transferred to a transfer material such as paper.

In such a developing device, the surface of the photoreceptor is uniformly slid by using a one-component developer consisting of toner alone or a two-component developer consisting of toner and magnetic carrier. The latent image is visualized.
In such a developer, the toner usually includes a thermoplastic resin, a colorant, a charge control agent, a fluidizing agent, and the like. The two-component developer includes a toner and a magnetic carrier such as ferrite. 2. Description of the Related Art In recent years, copiers have been required to have higher speed and higher image quality, and it is necessary that the entire developer including the toner has high fluidity and stable chargeability over a long period of time. In addition, such a developer is also required in a full-color copying machine that is rapidly spreading in recent years.

Conventionally, various post-treatments have been performed to stabilize the fluidity and chargeability of a developer. For example, JP-A-60-136755 and JP-A-60-2
Japanese Patent No. 38847 describes a developer in which silica and titanium are simultaneously added and mixed. However, in a developer obtained by mixing a conventional toner and a post-processing agent (silica or the like) with a Henschel mixer or the like, the above characteristics can be secured at the beginning of copying, but if the developer is used for a long period of time, the initial Characteristics cannot be stably maintained.

It is an object of the present invention to provide an electrostatic image developer which maintains initial fluidity and chargeability for a long period of time and can be used even under high stress conditions such as a high-speed copying machine.

According to the present invention , the BET specific surface area is 5 to 100 m.
Inorganic fine particles with a value of ² / g and a minor axis / major axis a of a ≦ 0.8
Toner having the toner (A) fixed to the surface layer, and externally added to the toner.
Of fine particles (A) mixed and fixed to the toner
It has a BET specific surface area of 1.2 times or more and has a minor axis / major axis
The fine particles (B) having a value b of b ≧ 0.7,
And b is a <b, thereby providing an electrostatic image developer.

Conventionally, when a post-processing agent such as silica or titanium oxide is simply mixed with a toner (developer) using a soft resin and post-processed, in the case of a two-component developer, especially when mixed with a carrier and stirred, the particle size is reduced. Fine silica is buried in the toner surface. In the case of the one-component toner, fine silica is buried in the toner surface layer at the time of contact with the layer thickness regulating blade. When the post-added treating agent is buried in the toner surface layer and the amount of the treating agent on the toner surface decreases, the fluidity of the toner and the developer decreases, the chargeability changes, and the performance of the developer decreases. .

In the developer of the present invention, fine particles (A) having a relatively large particle diameter are fixed on the toner surface by using a surface modifying device, and fine particles (B) having a small particle diameter are further externally treated thereon. By doing so, it is considered that the fine particles (A) form a blocking layer, and the fine particles (B) are prevented from being embedded in the toner.

The fine particles (A) fixed to the surface layer of the developer of the present invention include, for example , inorganic oxides such as titanium oxide, aluminum oxide, zinc oxide and silica.
Particularly, hydrophobic titanium oxide, hydrophobic aluminum oxide, and hydrophobic silica are preferable. Hydrophobicization in the present invention is to crush the hydroxyl group and carboxyl group bonded to the inorganic oxide, and the hydrophobization treatment is performed by reacting the inorganic oxide with a dialkyl halide silane, hexaalkyldisilazane, etc. at a high temperature. Done.

The fine particles (A) immobilized on the surface layer of the toner have a BET specific surface area of 5 to 100 m ² / g.
The average particle size is preferably from 0.02 to 1 μm. When the specific surface area of the fine particles (A) is less than 5 m ² / g, it is difficult to form a uniform blocking layer on the toner surface.
If it exceeds 00 m ² / g, the fine particles (A) themselves are buried in the toner and no longer function as a blocking layer. In addition,
In this specification, the BET specific surface area is a value measured by the BET one-point method. The addition amount of the fine particles (A) is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight based on 100 parts by weight of the toner base material. The amount of the fine particles (A) added is 0.
When the amount is less than 1 part by weight, the effect as a blocking layer is poor. On the other hand, when the amount is more than 10 parts by weight, free fine particles which cannot be fixed on the toner surface cause adverse effects such as toner scattering.

The fine particles (B) to be mixed and externally added to the toner having the fine particles (A) fixed thereto include inorganic fine particles such as silica, titanium oxide, aluminum oxide, and magnesium fluoride, an emulsion polymerization method, and a soap. Organic fine particles such as styrene, (meth) acrylic, benzoguanamine, melamine, Teflon, silicone, polyethylene, polypropylene, etc. granulated by wet polymerization such as free emulsion polymerization, non-aqueous dispersion polymerization or gas phase method. And particularly preferred is hydrophobic silica.

The fine particles (B) have a BET specific surface area,
It is 1.2 times or more of the fine particles (A), and 10 to 500 m ² /
g, the average particle size is preferably 0.05 μm or less. Fine particles (B) of the specific surface area of 10 m ² / g less, it is difficult to apply a homogeneous hydrophobic treatment, also 500 meters ² /
If it exceeds g, the fluidity of the developer does not improve. Fine particles (B)
Is added in an amount of 0.01 to 3 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the particles treated with the fine particles (A). If the added amount of the fine particles (B) is less than 0.01 parts by weight, sufficient fluidity cannot be obtained, while if it is more than 3 parts by weight, there are many fine particles which cannot be adhered to the toner surface, so that the chargeability of the toner is increased. Adverse effects such as instability of
Problems arise in chargeability and developability under high temperature / high humidity and low temperature / low humidity environments.

It is preferable that the fine particles (A) have a particle shape farther from a true sphere than the fine particles (B). That is, if the minor axis / major axis of the fine particles (A) = a and the minor axis / major axis of the microparticles (B) = b, a <b, especially a ≦ 0.8 and b ≧ 0.8.
7 is preferred. By setting a ≦ 0.8, the fine particles A are prevented from being embedded in the toner, and the blocking effect is improved. By setting b ≧ 0.7, the fluidity is improved without increasing the amount of the fine particles B added.

The particle diameter of the developer (toner) of the present invention is 15 μm or less, preferably 3 to 12 μm. As other components such as a binder resin and a charge control agent used in such a developer, those known as components of a conventional developer may be used.

(Binder Resin) The binder resin (binder resin) used in the developer of the present invention is not particularly limited as long as it is generally used as a binder in toners and developers. For example, polystyrene resin, poly
(Meth) acrylic resin, polyolefin resin, polyamide resin, polycarbonate resin, polyether resin, polysulfone resin, polyester resin, thermoplastic resin such as epoxy resin, or urea resin,
Urethane resins, urea resins, thermosetting resins such as epoxy resins, and their copolymers, block copolymers,
Graft copolymers and polymer blends are used. Further, for the purpose of improving the heat fixing property, an oligomer or a prepolymer component may be added in addition to the thermoplastic resin, or a part of the resin may be crosslinked.

Further, it is necessary that the toner used in a high-speed copying machine, which has been widely used in recent years, be fixed on transfer paper or the like in a short period of time and have a high separability from a fixing roller. Preferred binder resins for such high-speed copiers include homopolymers or copolymers synthesized from styrene monomers, (meth) acrylic monomers, (meth) acrylate monomers, and polyester resins. Can be

Regarding the molecular weight of these binder resins, the relationship among number average molecular weight (Mn), weight average molecular weight (Mw) and Z average molecular weight (Mz) is 1,000 ≦ Mn ≦ 7,000, 40
≦ Mw / Mn ≦ 70, 200 ≦ Mz / Mn ≦ 500, and preferably 2,000 ≦ Mn ≦ 7,000.
The oilless fixing toner has a glass transition temperature of 55 to 80 ° C, a softening point of 80 to 150 ° C, and a glass transition temperature of 5 to 80 ° C.
Preferably, it contains 20% by weight of a gelling component.

The translucent color toner is preferably a polyester resin which has vinyl chloride resistance, has translucency as a translucent color toner, and maintains adhesion to an OHP sheet. When these polyester resins are used for a translucent color toner, the glass transition temperature is 55 to 70 ° C., the softening point is 80 to 150 ° C., the number average molecular weight (Mn) is 2,000 to 15,000, and the molecular weight distribution (Mw /
It is preferable to use a linear polyester having Mn) of 3 or less.

As the resin of the translucent color toner, a linear urethane-modified polyester obtained by reacting a linear polyester resin with diisocyanate may be used. The linear urethane-modified polyester has a number average molecular weight of 2,000 to 15, comprising a dicarboxylic acid and a diol.
000 and an acid value of 5 or less, and 0.3 to 0.95 with respect to 1 mol of a linear polyester resin having a terminal group substantially consisting of a hydroxyl group.
The main component is a linear urethane-modified polyester resin obtained by reacting a mole of diisocyanate, the resin having a glass transition temperature of 40 to 80 ° C. and an acid value of 5 or less. In addition, acrylic to linear polyester,
A resin having the same glass transition temperature, softening point, and molecular weight as described above, which is obtained by modifying an aminoacrylic monomer or the like by a method such as graft copolymerization or block copolymerization, is also preferably used.

(Charge Control Agent) As the positive charge control agent, for example, azine compound nigrosine base EX, Bontron N-01,02,04,05,07,09,10,13
(Orient Chemical Co., Ltd.), oil black (Chuo Synthetic Chemical Co., Ltd.), quaternary ammonium salt P-51, polyamine compound P-52, Sudan Chief Shaw BB
(Solvent black 3: CI No. 2615
0), Fettschwald HBN (CI No. 26)
150), brilliant spirit varnish TN (manufactured by Pharvenf Abriken Bayer), alkoxylated amines, alkylamides, molybdate chelate pigments, imidazole compounds and the like.

On the other hand, as the negative charge control agent, for example, a chromium complex salt type azo dye S-32, 33, 34, 35, 37,
38, 40, 44 (manufactured by Orient Chemical Co., Ltd.), Aizen Spiron Black TRH, BHH (manufactured by Hodogaya Chemical Co., Ltd.), Kayset Black T-2,004 (manufactured by Nippon Kayaku Co., Ltd.), copper phthalocyanine paint S- 39 (manufactured by Orient Chemical Industries), chromium complex salt S-34, 44, E-81,
82 (manufactured by Orient Chemical Industries), zinc complex salt E-84
(Manufactured by Orient Chemical Industries), aluminum complex salt E-8
6 (manufactured by Orient Chemical Industries), salicylic acid derivative E-
89 (manufactured by Orient Chemical Industry Co., Ltd.) and the like.

The amount of the charge control agent to be added is appropriately selected depending on the type of the toner, the toner additive, the type of the binder resin, and the like, and the development system (two-component or one-component) of the toner. For example, when the toner is contained in a toner manufactured by a pulverization method or a suspension method, the toner constituent resin
0.1 to 20 parts by weight, preferably 1 to 1 part by weight
0 parts by weight. If the amount of the charge control agent is less than 0.1 part by weight, a desired amount of charge cannot be obtained. If the amount is more than 20 parts by weight, the amount of charge becomes unstable, and the fixability deteriorates.

On the other hand, when the charge control agent is used by adhering and immobilizing it on the toner surface, 0.001 to 10 parts by weight, preferably 0.05 to 10 parts by weight, per 100 parts by weight of the toner particles is used.
2 parts by weight, more preferably 0.1 to 1 part by weight. If the amount is less than 0.001 part by weight, the amount of the charge control agent present on the surface layer of the toner particles is small and the charge amount is insufficient. If the amount is more than 10 parts by weight, the charge control agent does not adhere to the toner surface. Sufficient, and the charge control agent is released from the toner surface during use.

(Colorant) As the colorant to be incorporated in the toner for developing an electrostatic image of the present invention, various organic or inorganic pigments and dyes of the following colors can be used.

That is, black pigments include carbon black, copper oxide, manganese dioxide, aniline black,
Activated carbon, non-magnetic ferrite, magnetic ferrite, magnetite and the like can be mentioned.

Examples of the yellow pigments include graphite, 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, and benzidine. Yellow GR, quinoline yellow lake, permanent yellow NCG, tartrazine lake and the like.

Examples of the orange pigment include red lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indathrene brilliant orange RK, benzidine orange G, and indathrene brilliant orange GK.

Examples of red pigments include red iron red, cadmium red lead, mercury sulfide, cadmium, permanent red 4R, lithol red, pyrazolone red, wotting red, calcium salt, lake red C, lake red D, brilliant carmine 6B, Eosin rake,
Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B and the like.

Examples of the violet pigment include manganese violet, fast violet B, and methyl violet lake.

As the blue pigment, navy blue, cobalt blue, alkali blue lake, Victoria blue lake,
Phthalocyanine blue, metal-free phthalocyanine blue,
Phthalocyanine blue partial chlorine compound, Fast Sky Blue, Indaslen Blue BC and the like.

Examples of the green pigment include chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G, and the like.

As white pigments, zinc white, titanium oxide,
Examples include antimony white and zinc sulfide.

The extender includes baryte powder, barium carbonate, clay, silica, white carbon, talc, alumina white and the like.

Examples of the dye include various dyes such as basic, acidic, disperse, and direct dyes, such as nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

These coloring agents can be used alone or in combination of two or more. Usually, 1 to 20 parts by weight, more preferably 2 to 10 parts by weight, is mixed with 100 parts by weight of the binder resin. Is preferred. If the amount of the coloring agent is more than 20 parts by weight, the fixability of the toner is reduced. On the other hand, if the amount is less than 1 part by weight, a desired image density cannot be obtained.

As the colorant when the toner of the present invention is used as a translucent color toner, various pigments and dyes of various colors as shown below can be used.

For example, yellow pigments include C.I. I. 103
16 (Naphthol Yellow S), C.I. I. 11710
(Hanza Yellow 10G), C.I. I. 11660 (Hanza Yellow 5G), C.I. I. 11670 (Hanza Yellow 3G), C.I. I. 11680 (Hanza Yellow G),
C. I. 11730 (Hanza Yellow GR), C.I. I.
11735 (Hanza Yellow A), C.I. I. 11740
8 (Hanza Yellow RN), C.I. I. 12710 (Hanza Yellow R), C.I. I. 12720 (Pigment Yellow L), C.I. I. 21090 (benzidine yellow), C.I. I. 21095 (benzidine yellow G),
C. I. 21100 (benzidine yellow GR), C.I.
I. 20040 (Permanent Yellow NCG), C.I.
I. 21220 (Vulcan Fast Yellow 5), C.I.
I. 21135 (Vulcan Fast Yellow R) and the like.

As the red pigment, C.I. I. 12055
(Stalin I), C.I. I. 12075 (permanent orange), C.I. I. 12175 (Resole Fast Orange 3GL), C.I. I. 12305 (Permanent Orange GTR), C.I. I. 11725 (Hanza Yellow 3R), C.I. I. 21165 (Vulcan Fast Orange GG), C.I. I. 21110 (benzidine orange G), C.I. I. 12120 (permanent thread 4
R), C.I. I. 1270 (Paralleled), C.I. I. 12
085 (firered), C.I. I. 12315 (Brilliant Fast Scarlet), C.I. I. 1231
0 (permanent thread F2R), C.I. I. 12335
(Permanent thread F4R), C.I. I. 12440
(Permanent thread FRL), C.I. I. 12460
(Permanent thread FRLL), C.I. I. 12420
(Permanent thread F4RH), C.I. I. 12450
(Light fastened toner B), C.I. I. 124
90 (permanent carmine FB), C.I. I. 1585
0 (Brilliant Carmine 6B) and the like.

As the blue pigment, CI 7410
0 (metal-free frotocyanin blue), C.I. I. 7416
0 (frotocyanin blue), C.I. I. 74180 (fast sky blue) and the like.

These coloring agents may be used alone or in combination of two or more. The amount of such a coloring agent is
The amount is 1 to 10 parts by weight, more preferably 2 to 5 parts by weight, based on 100 parts by weight of the binder resin contained in the toner particles. When the amount of the coloring agent is more than 10 parts by weight, the fixing property and the light transmittance of the toner are reduced. On the other hand, when the amount is less than 1 part by weight, a desired image density may not be obtained. (Other Additives) Further, an offset preventing agent may be used in combination with the toner of the present invention to improve fixability. As the anti-offset agent, various waxes, especially low molecular weight polypropylene and polyethylene, or polyolefin wax such as oxidized polypropylene and polyethylene are preferable. These waxes have a number average molecular weight (Mn) of 1,000 to 20,000 and a softening point (T
m) is preferably 80 to 150 ° C. When the number average molecular weight Mn is 1,000 or less, or the softening point Tm is 80 ° C or less, the wax is not uniformly dispersed in the binder resin in the toner, and only wax is eluted on the toner surface. In addition to undesired results, photoreceptor contamination such as filming is caused.
On the other hand, if the number average molecular weight Mn exceeds 20,000 or the softening point Tm exceeds 150 ° C., not only the compatibility with the binder resin deteriorates, but also desired effects such as high temperature offset resistance and the like can be obtained. Absent. In addition, when used together with a binder resin having a polar group in terms of compatibility,
Waxes having polar groups are desirable.

(Production Method of Developer) In order to prepare the developer of the present invention, first, a core material toner is prepared by a known method such as kneading and pulverizing the above components such as a binder resin, a pigment and a charge control agent. Prepare. The obtained toner is mixed and placed in a stirring device, and the fine particles (A) are embedded in the surface of the toner. Such a treatment may be carried out at one time. First, the particles are adhered by van der Waals force and electrostatic force, and then treated with a device having higher stirring and mixing power to fix the fine particles (A) on the surface layer of the toner. You may. Next, the toner and the fine particles (B) are mixed and stirred to obtain a desired toner.

Various devices may be used for fixing the fine particles (A) to the surface layer of the toner. For example, a high-brightness impact method using a high-speed impact method (Nara Machinery Co., Ltd.), a cosmos system (Kawasaki Heavy Industries, Ltd.), a mechano-fusion system using a dry mechanochemical method (Hosokawa Micron), a mechano mill (Okada) Seiko Co., Ltd.), Suffering system applying the hot air reforming method (Nippon Pneumatic Industries Co., Ltd.), wet type
Apparatuses such as a disperse coat (manufactured by Nisshin Seifun Co., Ltd.) and a coatmizer (manufactured by Freund Corporation) to which the coating method is applied are preferably used, but are not limited thereto.

(Carrier) When the toner of the present invention is used as a two-component developer, an iron or ferrite carrier is used as a carrier. Such carrier materials include metals such as iron, nickel, and cobalt, and zinc, antimony, aluminum, lead, tin, bismuth, beryllium, manganese, selenium, tungsten, zirconium,
Alloys or mixtures with metals such as vanadium and vanadium, oxides, metal oxides such as titanium oxide and magnesium oxide, nitrides such as chromium nitride and vanadium nitride, and mixtures and carbides with carbides such as silicon carbide and tungsten carbide Ferrite, and mixtures thereof, and the like.

Further, a coating carrier coated with various synthetic resins or ceramic layers using the iron or ferrite carrier as a core material may be used. As the synthetic resin, for example, polyethylene resin, poly (meth)
Acrylic resin, polyolefin resin, polyamide resin, polycarbonate resin, polyether resin, polysulfonic acid resin, polyester resin, epoxy resin, polybutyral resin, urea resin, urethane / urea resin, silicon resin, polyethylene Various thermoplastic resins such as a series resin, a Teflon-based resin, and the like, and thermosetting resins and mixtures thereof, and copolymers, block polymers, graft polymers, and polymer blends of these resins are used. Further, in order to improve the chargeability, resins having various polar groups may be used. The ceramic coating is obtained by coating various ceramic materials by a method such as a thermal spraying method, various plasma methods, and a sol-gel method.

Further, various organic and / or inorganic materials may be coated by dispersing and / or dissolving them in order to improve the chargeability and other various developer properties, and these materials may be fixed on the surface of the coating carrier. May be used. As an apparatus for performing carrier coating and immobilization processing of various materials,
Various coating apparatuses such as a spray dryer and a tumbling flow tank and the above-described various surface reforming apparatuses are used.

Further, a binder type carrier may be used. That is, the various magnetic materials and the various synthetic resins used for the coating layer are used as a binder resin, and then, if necessary, various organic and / or inorganic materials are added, followed by mixing, kneading, and pulverization to obtain the necessary granules. The one adjusted to the diameter is used.

The average particle size of the carrier is from 20 to 20.
Although a thing of 0 μm is generally used, it is appropriately set according to the developing method and the like. Generally, the carrier particle size is 20 μm
If it is smaller, there is a problem that the carrier itself is developed. If it is larger than 200 μm, there is a problem that the texture of the image becomes coarse.

Since the developer of the present invention has excellent durability and stability under high stress, it is preferable as a toner used under conditions where stress is easily applied. For example, a toner using a low softening point resin, such as a small particle size toner having an average particle size of 10 μm or less, a translucent color toner, a high-speed system toner, and a low-temperature fixing toner, is particularly preferable. When used as a two-component developer, the toner is preferably used in combination with an iron powder having a true specific gravity of 4 or more and a ferrite carrier. The developing device using the one-component toner has an effect in the case of a developing device having a toner conveying member and a toner layer thickness regulating member and forming a thin layer of charged toner on the toner conveying member.

[0049]

Next, the present invention will be described more specifically based on examples.

[Example 1 (Toner a)] Ingredients Parts by weight Styrene-n-butyl methacrylate 100 (softening point 132 ° C., glass transition point 60 ° C.) Carbon black (MA # 8, manufactured by Mitsubishi Kasei Corporation) 8 Low molecular weight Polypropylene (manufactured by Sanyo Chemical Industries: Viscol 550P) 5 Chromium complex dye 5 (manufactured by Hodogaya Chemical Co., Ltd .: Aizen Spiron Black T)
RH) After the above components were sufficiently mixed by a ball mill, they were kneaded on three rolls heated to 140 ° C. The kneaded product was left to cool, coarsely pulverized using a feather mill, and further finely pulverized using a jet mill. The obtained pulverized product was subjected to air classification to obtain a toner having an average particle size of 9 μm. This toner and the toner 1
1.5 parts by weight of hydrophobic titanium oxide (1) (00 parts by weight) (fine particles (A): BET specific surface area 30 m ² / g,
(Minor axis / major axis = 0.7, average particle diameter 50 mμ) was put into a Henschel mixer, and mixed and stirred at 1,500 rpm for 2 minutes, and titanium oxide fine particles (A) were applied to the surface of the toner by van der Waals force and static. It was electrically deposited. Next, the hybridization system NHS manufactured by Nara Machinery Works
Using type-1 and treating at 6,000 rpm for 3 minutes,
The fine particles (A) were fixed to the toner surface layer to obtain a toner having an average particle size of 9 μm. With respect to 100 parts by weight of this toner, hydrophobic silica R-974 (fine particles (B): manufactured by Nippon Aerosil Co., Ltd., BET specific surface area: 180 m ² / g, minor axis / major axis = 0.9, average particle diameter: 12 mμ) 0.2 The parts by weight were put into a Henschel mixer and mixed and stirred at 1,500 rpm for 1 minute to obtain a toner a.

Example 2 (Toner b) Component Ingredients by weight Polyester resin (manufactured by Kao Corporation: Tufton NE-382) 100 Brilliant Carmine 6B (CI. 15850) 3 Zinc complex salt E-84 (Orient Chemical) (5) A toner b having an average particle diameter of 9 μm was obtained by treating the above-mentioned materials as toner components in the same manner as in Example 1.

Example 3 (Toner c) In Example 1, hydrophobic titanium oxide (2) was used instead of hydrophobic titanium oxide (1) (BET specific surface area 40 m ² / g, minor axis / major axis = 0.
65, average particle diameter 35 mμ) 1.5 parts by weight, silica HDK H-2000 (manufactured by Wacker Inc .: BET specific surface area 120 m ² / g, minor axis / major axis = 0.9, average instead of silica R-974) A toner c having an average particle size of 9 μm was obtained by the same composition and method except that 0.5 parts by weight of the particles were used.

[0053]

[0054]Example 4 (Toner d)  In Example 1, the conditions for pulverizing and classifying the toner were changed.
As a result, fine particles having an average particle diameter of 6 μm were obtained. Get
Fine particles, hydrophobic titanium oxide (1) (fine particles
(A)) 1.5 parts by weight and hydrophobic silica HDK H-
2000 (particulate (B)) other than using 0.5 parts by weight
Has an average particle size of 6 by the same composition and method as in Example 1.
μmToner dI got

Comparative Example 1 ( Toner e ) An average particle size of 9 μm was obtained by the same composition and method as in Example 1, except that the treatment with titanium oxide (1) (fine particles (A)) was not performed. The toner e was obtained.

Comparative Example 2 ( Toner f ) The average particle size was determined by the same composition and method as in Example 2, except that the surface treatment with titanium oxide (1) (fine particles (A)) was not performed. 9 μm of the toner f was obtained.

[Comparative Example 3 ( Toner g )] An average was obtained by the same composition and method as in Example 3, except that the surface treatment with the hydrophobic titanium oxide (2) (fine particles (A)) was not performed. 9μm particle size toner
-G was obtained.

[Comparative Example 4 ( Toner h )] The average particle size was determined by the same composition and method as in Example 4 , except that the surface treatment with titanium oxide (1) (fine particles (A)) was not performed. 6 μm of toner h was obtained.

[Comparative Example 5 ( Toner i )] Except that the surface treatment was not performed with titanium oxide (1) (fine particles (A)) and the same amount was used as a post-treatment agent together with hydrophobic silica R-974 in Example 1. A toner i having an average particle size of 9 μm was obtained by the same composition and method.

[0060]Example 5 (Toner j)  In Example 1, instead of hydrophobic titanium oxide (1),
Aqueous aluminum oxide (BET specific surface area 80m²/ G,
Minor axis / major axis = 0.78, average particle size 21 mμ) 1.0 part by weight
Average particle size by the same composition and method except that
9 μmToner jI got

Comparative Example 6 ( Toner k ) In Example 1, hydrophobic silica HDK H-2000 (manufactured by Wacker: BE) was used instead of the hydrophobic titanium oxide (1).
A toner k having an average particle diameter of 9 μm was obtained by the same composition and method except that 1.0 part by weight (T specific surface area: 120 m ² / g, minor axis / major axis = 0.9, average particle diameter: 12 mμ) was used.

(Manufacture of Carrier) The toner was evaluated using the following carriers.

[Carrier A] Ferrite carrier F-3
A carrier obtained by coating the surface of a 00 (manufactured by Nippon Iron Powder Co., Ltd .: 50 μm) with a silicon-based resin is referred to as a carrier A (specific gravity 5.2).

[Carrier B] Ferrite carrier F
-300 (manufactured by Nippon Iron Powder Co., Ltd .: 50 μm) coated with an acrylic resin on carrier B (specific gravity 5.
2).

[Carrier C] Component Weight parts Polyester resin (manufactured by Kao Corporation: NE-1110) 100 Inorganic magnetic powder (manufactured by Toda Kogyo: EPT-1000) 500 Carbon black (manufactured by Mitsubishi Kasei: MA # 8) 2) The above materials were sufficiently mixed and pulverized with a Henschel mixer. Next, the cylinder part 180 ° C, the cylinder head part 17
Melt kneading was carried out using an extrusion kneader set at 0 ° C.
The kneaded material was cooled, coarsely pulverized, and then finely pulverized by a jet mill.
Further, the particles were classified using an air classifier, and the average particle size was 55 μm.
Of magnetic carrier C (specific gravity 3.4) was obtained.

[0066]Evaluation of the physical properties  (1) Toner particle size The average toner particle size is measured using a Coulter Counter TA-II.
Mold (manufactured by Coulter Counter Co., Ltd.)
The relative weight distribution for each particle size was measured with a Patcher tube.

(2) Carrier Particle Size The carrier particle size is determined by the Microtrac model 7995-
The average particle size was measured using 10 SRA (manufactured by Nikkiso Co., Ltd.).

(3) BET Specific Surface Area Using a flowsorb type 2300 manufactured by Shimadzu Corporation,
It was measured by the ET one-point method.

(4) Evaluation of Initial Stage, Moisture Resistance and Printing Durability of Developer
Carriers were mixed at a ratio of 5/95 to prepare a two-component developer. Regarding the developers using the toners of Example 4 and Comparative Example 5 , the copying machine EP-8600 (Minolta Camera)
(Manufactured by Co., Ltd.). Example 1, Example 5, Comparative Example 1,
For the developer using the toner of Comparative Example 6, the copying machine EP
-8600 (manufactured by Minolta Camera Co., Ltd.) was used in which the developing device was improved so that mixing and stirring with the ferrite carrier became good. Further, the copying machine EP-570Z (Minolta Camera Co., Ltd.) was used for Example 2 and Comparative Example 2.
The fixing unit manufactured by Co., Ltd.) was improved to an oil coating system. Using these, the chargeability (Q / M), the scattering property of the toner, and the fog on the image were evaluated under the initial conditions, high humidity, and endurance printing. Table 1 shows the results.

Initial Evaluation (i) Chargeability (Q / M) The initial charge amount was measured using each sample prepared by mixing toner / carrier at a ratio of 5/95.

(Ii) Scattering property The scattering amount of the toner at the time of measuring the charging property was examined. The scattering amount was measured using a digital dust meter P5H2 (manufactured by Shibata Chemical Co., Ltd.). 10c of the dust meter and magnet roll
m, and the dust meter reads toner particles that are generated when the magnet roll is rotated as dust, and displays the result as counts per minute (cpm). A three-step evaluation was performed by setting the obtained scattering amount to 300 cpm or less as 、, 500 cpm or less as Δ, and when the scattering amount was more than 500 cpm as ×. Although it can be practically used at the rank of Δ or higher, ○ is desirable.

(Iii) Image Evaluation (Fog on Image) Initial image formation was performed using the above-described copying machine. Regarding the fog on the image, the toner fog on the white background image was evaluated and ranked. Although it can be practically used at the rank of Δ or higher, it is preferable that the rank is at least ○.

Moisture resistance test Each copy machine was left under high humidity of 35 ° C. and a relative humidity of 85% for 24 hours, and then (i) charge amount, (i)
i) scattering properties and (iii) image evaluation were performed. The symbols in the table are the same as above.

Printing durability A printing durability test of up to 100,000 sheets was performed using a chart having a B / W ratio of 6% to evaluate the image and fog. In the table, ○ means a practically usable area, and × means a practically problematic area.

(4) Translucency In Example 2 and Comparative Example 2, a translucency test was also performed. The translucency was visually evaluated for the color vividness of the projected image when the fixed image on the OHP sheet was projected by the OHP projector. The results are shown in Table 1. In the table, ○ means a practically usable area in terms of color reproduction.

(5) Printing durability test in one-component development system (Example 3 and Comparative Example 3) To evaluate the printing durability in the one-component development system, 1,000 sheets were printed using the copying machine shown in FIG. Printing durability was evaluated.
As shown in FIG. 1, in the developing device 1, the toner is stored in a toner storage tank 6 and is agitated by an agitator 5. The toner adheres to the surface of the developing roller 3 and is conveyed. The thickness of the toner is regulated by the blade 4 to form a uniform thin toner layer, and the electrostatic latent image on the photosensitive drum 7 is developed.

At this time, the fusion of the toner on the surface of the blade 4 and the surface of the developing roller 3 was visually evaluated, and three-stage evaluation of ○, Δ, and × was performed. Although it can be used practically with Δ or more, ○ is desirable. The one-component developing type developing device has a toner conveying member and a toner layer thickness regulating member, and forms a thin layer of charged toner on the toner conveying member.

[0078]

[Table 1]

[0079]

The developer of the present invention is excellent in durability, and retains excellent initial properties such as fluidity and chargeability even when used for a long time. The effect is great in the case of a two-component developer using a carrier that gives a high stress to the toner, such as an iron powder having a large specific gravity or a ferrite carrier. Also, it shows excellent durability in a one-component developing device.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a copying machine of a one-component developing system using a developer of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 3 Developing roller 4 Blade 5 Agitator 6 Toner storage tank 7 Photoconductor drum

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-90176 (JP, A) JP-A-2-61649 (JP, A) JP-A-1-223468 (JP, A) JP-A-3- 61953 (JP, A) JP-A-4-198947 (JP, A) JP-A-63-240557 (JP, A) JP-A-63-198070 (JP, A) JP-A-1-126665 (JP, A) JP-A-2-108069 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (5)

(57) [Claims] 1. The BET specific surface area is 5 to 100 m ² / g .
And inorganic particles (A) having a ratio of minor axis / major axis a ≦ a ≦ 0.8
A toner fixed to the surface layer, organic and and minor axis / major axis value b a BET specific surface area of 1.2 times or more of the microparticle (A) fixed to the toner are externally added mixed in the toner b
The fine particles (B) of ≧ 0.7 , wherein the a and the b
An electrostatic image developer , wherein a <b . 2. The fine particles (B) having a BET specific surface area of 1
The electrostatic image developer according to claim 1, wherein the 0~500m a ² / g. 3. The fine particles (A) having a BET specific surface area of 5
~80m a ² / g, the electrostatic charge image developer according to claim 1, wherein the BET specific surface area of 120~500m ² / g of the fine particles (B). 4. The electrostatic image developer according to claim 1, wherein said developer is a two-component developer containing a magnetic carrier. 5. A one-component developer used in a one-component developing method in which the developer has a toner layer thickness regulating member provided in contact with a toner conveying member and forms a charged toner layer on the toner conveying member. The electrostatic image developer according to claim 1, wherein