JP2002244339A - Toner for developing electrostatic images - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent filming of a toner on a surface of a carrier, a sleeve and a photoreceptor, to reduce abrasion of a photoreceptor surface, and to provide stable triboelectric charging characteristics and image quality when copying a large number of sheets. To provide a toner for developing an electrostatic image. SOLUTION: The present invention provides an aM ₂ O · bAl ₂ O ₃ .cSi on a surface of a toner particle containing a binder resin and a colorant.
O ₂ .dRmAn.yH ₂ O (wherein, M is Na and / or K, R is at least one selected from the group consisting of Na, K, Ca, and Mg, and A is CO ₃ , SO ₄ , NO ₃ , OH
And Cl is at least one member selected from the group consisting of
6, b is 2 to 8, c is 2 to 12, d is 0 to 4, m is 1 to
2, n is 1 to 3 and y is 0 to 32). The toner for developing an electrostatic image is formed by adhering aluminosilicate particles having a composition represented by the formula:

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developing toner for dry developing an electrostatic image formed in electrophotography, electrostatic printing, electrostatic recording, and the like.

[0002]

2. Description of the Related Art A dry type developer applied to an image forming apparatus for developing an electrostatic image is a two-component developer in which a toner is mixed with a carrier, and a magnetic one-component developer in which a toner itself contains a magnetic powder. And non-magnetic one-component developers in which the magnetic powder is not contained in the toner itself. Various proposals have been made for each developing method. Conventional toners used in each of these developing methods include a binder resin composed of styrene / acrylate resin, carbon black and other coloring agents, various charge control agents represented by metal-containing dyes, and After mixing the polyolefins and other additives as low-temperature fixability and anti-offset agent in a prescribed formulation, melt-kneading, pulverizing, classifying, and then creating toner particles, then necessary to improve fluidity What has hydrophobic silica adhered to the toner particles according to the above has been used.

However, when the toner according to the prior art described above is used in a two-component developing system, the toner adheres electrostatically to the carrier surface or fuses mechanically and thermally on the carrier surface during the process of copying a large number of sheets. Changes, the characteristics of the developer change, and the triboelectricity deteriorates, causing various problems.

[0004] The adhesion of toner to the carrier surface is particularly remarkable in a high-speed copying machine. That is, in a high-speed copying machine, since the time from the supply of toner to the development on the photosensitive member is short, a necessary amount of triboelectricity must be secured in a short time. Therefore, in the developing device, the sleeve and the stirring blade rotate at a high speed in order to give a sufficient amount of frictional charge to the toner. In such a developing device, the stress on the toner and the carrier is large as compared with the low-speed copying machine, and the toner is easily fused (filming) to the surface of the carrier, so that the charge amount becomes nonuniform and the durability of the developer is reduced. .

On the other hand, when the toner according to the conventional technique is applied to a non-magnetic one-component developing system, a phenomenon in which the toner is fused to a developing sleeve by a pressing force of a blade member or heat, a so-called sleeve fusion (filling to the sleeve). Problem). The sleeve fusion makes the charge amount non-uniform and makes it impossible to maintain a good image.

Further, the toner according to the prior art is
Filming occurs as a result of the toner remaining on the photoconductor after transfer being accumulated on the photoconductor, which is common to all the development systems including the magnetic one-component development system. As a result, the charge amount on the surface of the photoconductor becomes improper. There was also a problem of uniformity.

As means for solving these problems, powdery inorganic fine particles or magnetic powders such as silica, titanium oxide, alumina or ceramic, metal salts of fatty acids, fine particles of fluorine-based resin, etc. It has been proposed to apply a powder.

However, the fine particles conventionally proposed are hardly electrostatically adhered to the toner surface, and if strong energy is applied to fix the fine particles to the surface, the fine particles are buried in the toner surface, which is expected. There is a problem that the effect cannot be sufficiently exhibited. Further, the inorganic fine particles conventionally used have a problem that the surface of a relatively weak photoconductor such as OPC is damaged and cut off. If the surface of the photoreceptor is damaged, the image is immediately adversely affected, so that the optimum use conditions are limited, and it has been difficult to maintain these conditions continuously.

In addition, the above-mentioned problem of the filming of the toner on the surface of the carrier, the developing sleeve and the photoreceptor has become widespread in recent years, and the toner removed from the photoreceptor after fixing is reused (recycled). This became particularly serious in a developing device to which a system for performing the above was added. That is, when the toner is reused, the toner (part of the toner image) remaining on the surface of the photoconductor after the toner image developed on the surface of the photoconductor is transferred to the recording sheet
Is scraped off with a cleaning blade or a fur brush or the like, and the toner is conveyed to a developer container in which the developer is stored and collected in unused developer. However, the recovered toner is subjected to a thermal or mechanical load during a recovery process in which the toner is scraped off from the photoreceptor by a cleaning blade or transported to a developer container. Buried in the toner particles,
The function of the fine particles was no longer fully exhibited.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the toner from being filmed on the carrier, the developing sleeve and the surface of the photosensitive member, which is a problem of the conventional toner for electrostatic charge development, and to prevent the photosensitive member from being shaved. It is an object of the present invention to provide a toner for electrostatic charge development having a small amount of stable triboelectric charging characteristics and excellent image quality when copying a large number of sheets.

[0011]

According to the present invention, a surface of a toner particle containing a binder resin and a colorant is aM ₂ O.bAl
₂ O ₃ .cSiO ₂ .dRmAn.yH ₂ O (where M
Is Na and / or K, R is Na, K, Ca, and Mg
At least one member selected from the group consisting of: A is CO ₃ , S
At least one selected from the group consisting of O ₄ , NO ₃ , OH and Cl, a is 1 to 6, b is 2 to 8, c is 2 to 12, d is
Is 0 to 4, m is 1 to 2, n is 1 to 3, and y is 0 to 32). Aluminosilicate particles having a composition represented by Toner.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The toner particles in the present invention are mainly composed of a binder resin and a colorant. Examples of the binder resin of the toner particles include polystyrene, poly-p-chlorostyrene, polyvinyl toluene, styrene-p-chlorostyrene copolymer, styrene such as styrene-vinyltoluene copolymer, and homopolymers of substituted styrene and the like. Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Copolymer of styrene and acrylate such as acrylate-n-butyl copolymer; styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-n-butyl methacrylate copolymer Copolymers of styrene and methacrylic acid esters, such as union; multi-component copolymers of styrene with acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers, styrene-vinyl methyl ether copolymers, styrene-butadiene Styrene-based copolymers of styrene with other vinyl-based monomers such as copolymers, styrene-vinyl methyl ketone copolymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid ester copolymers; polymethyl methacrylate , Polybutyl methacrylate, polyacrylic acid Ester resins, polyester resins, polyvinyl acetate, polyamide resin, epoxy resin,
Polyvinyl butyral resin, polyacrylate phenol resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, polyvinyl chloride, polyvinylidene chloride, and the like can be used alone or in combination.

The coloring agents include carbon black, aniline blue, chaco oil blue, chrome yellow, ultramarine blue, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal and rhodamine dyes. , Anthraquinone dyes, monoazo and disazo pigments, mixtures thereof and others. It is necessary that these colorants are contained in such a ratio that a visible image having a sufficient image density is formed, and usually a ratio of about 1 to 20 parts by weight with respect to 100 parts by weight of the binder resin is preferable.

Preferably, a charge control agent is added to the toner particles. As the positive charge control agent,
For example, a modified product of nigrosine and a fatty acid metal salt, etc., tributylbenzylammonium-1-hydroxy-4-
Naphthosulfonates, quaternary ammonium salts such as tetrabutylammonium tetrafluoroborate, dibutyltin oxide, dioctyltin oxide, diorganotin oxides such as dicyclohexyltin oxide, dibutyltin borate, dioctyltin borate,
Diorganotin borates such as dicyclohexyl tin borate can be used alone or in combination of two or more. Of these, particularly preferred are nigrosine compounds and quaternary ammonium salts. The preferred addition amount is 0.1 to 5% by weight. As the negatively chargeable charge control agent, for example, an acetylacetone metal complex, a monoazo metal complex, an organic metal compound such as a naphthoic acid or salicylic acid-based metal complex or a salt, a chelate compound or the like can be used alone or in combination of two or more kinds. . Of these, salicylic acid-based metal complexes and monoazo metal complexes are particularly preferably used. The preferred addition amount is 0.1 to 5% by weight. These may be used alone or as a mixture.

It is preferable to add a release agent in order to ensure releasability between the fixing heat roll and the toner. Release agents include waxes, higher fatty acids, higher fatty acid amides, hardened castor oil and the like. Examples of the wax include polyalkylene waxes such as low molecular weight polyethylene and low molecular weight polypropylene, paraffin wax, Fischer-Tropsch wax, carnauba wax, candelilla wax, rice wax and the like. These release agents can be used alone or as a mixture.

In order to protect the photoreceptor and obtain a high-quality image without deteriorating the developing characteristics, the toner particles of the present invention may contain a higher fatty acid, an olefin-maleic anhydride copolymer or the like as appropriate. It may be added.

When the electrostatic image developing toner of the present invention is used as a magnetic toner, a magnetic powder is contained in the toner particles. As the magnetic material, ferrite, magnetite, hematite and the like, alloys and compounds such as iron, manganese, cobalt, nickel, copper, zinc, magnesium and the like, and substances known as ferromagnetic materials such as iron powder can be used. The average particle size of these magnetic materials is about 0.05 to 5 μm, and the content is preferably 20 to 120 parts by weight based on 100 parts by weight of the binder resin.

The aluminosilicate particles adhered to the surface of the toner particles of the present invention are aM ₂ O.bAl ₂ O ₃ .c
SiO ₂ .dRmAn.yH ₂ O (wherein, M is at least one selected from the group consisting of Na and / or K, R is Na, K, Ca, and Mg, and A is CO ₃ , SO ₄ , NO ₃ ,
At least one selected from the group consisting of OH and Cl, a is 1 to 6, b is 2 to 8, c is 2 to 12, d is 0 to 4, m is 1 to 2, n is 1 to 3, y Represents a number from 0 to 32).

The aluminosilicate particles of the present invention are composed of secondary particles which are aggregates of primary particles. The primary particles have a needle-like, plate-like, or column-like shape. Here, the needle shape means that the thickness is 0.5 μm or less and the length is 2.0 or more in aspect ratio to the thickness, and the plate shape means that the thickness is 0.3 μm or less. , Means that the plate diameter is 2.0 or more in aspect ratio with respect to the thickness, and the column shape is 0.05 μm or more in thickness and 1.0 or more in length in thickness to aspect ratio. Less than 2.0. Further, the aluminosilicate particles of the present invention are secondary particles in which the above-mentioned primary particles are aggregated in a spherical, tetrapot-like or massive form. The shapes of the primary particles and the secondary particles are determined by manufacturing conditions. Among them, the shape of the aluminosilicate particles used in the present invention is not particularly limited to primary particles and secondary particles. As specified, the primary particles are preferably columnar and the secondary particles are preferably tetrapod-shaped. Further, the average particle size of the aluminosilicate secondary particles of the present invention is preferably 1 to 10 μm, and 2 to 4 μm.
Is more preferred.

The method for producing the aluminosilicate of the present invention is not particularly limited.
As disclosed in Japanese Patent No. 228127, Al compound and Si compound are converted to CO ₃ ²⁻ , SO ₄ ²⁻ , NO ₃ ⁻ ,
^And a method in which the reaction is performed in an alkaline solution in the presence of-. Further, specifically, a product name “Luminous SP” series marketed by Kao Corporation is suitably used in the present invention.

In the present invention, the amount of aluminosilicate particles deposited on the surface of the toner particles is preferably from 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner particles. More preferably, it is 0.1 to 3.0 double dragon parts. If it is less than 0.1 part by weight, the effect of preventing filming is small. If the amount is more than 5.0 parts by weight, the action of the toner is impaired.

In the present invention, the method of adhering the aluminosilicate particles to the surface of the toner particles may be performed by using a mixing device such as a Henschel mixer or a super mixer to cover the surfaces of the toner particles with the aluminosilicate particles. At least a portion of the aluminosilicate particles may be embedded in the surface of the toner particles using a surface modification device such as a hybridization system.

Further, it is preferable to adhere inorganic oxide fine particles as a fluidizing agent depending on the purpose. As the inorganic oxide fine particles, silica fine particles, titanium oxide fine particles and the like can be preferably used.

[0024]

The present invention will be described below based on examples and comparative examples. In addition, all the compounding parts number means a weight part. <Preparation of Toner Particles A>-100 parts of styrene-acrylate copolymer resin (trade name: CPR-120, manufactured by Mitsui Chemicals, Inc.)-6 parts of carbon black (trade name: REGAL330R, manufactured by Cabot Corporation)-Chromium-containing dye 1 part (trade name: Bontron S-34, manufactured by Orient Chemical Industry Co., Ltd.) ・ 3 parts of polyethylene wax (trade name: PE-130, manufactured by Clariant) The above materials are dry-mixed with a super mixer, and then heat-melted with a twin-screw extruder. After kneading to obtain a kneaded product, the mixture was pulverized by a jet mill and classified by an air-flow classifier to obtain a volume average particle diameter of 10%.
μm negatively chargeable toner particles were obtained. <Preparation of toner particles B>-100 parts of polyester resin (trade name: FC-664, manufactured by Mitsubishi Rayon Co., Ltd.)-6 parts of carbon black (trade name: REGAL330R, manufactured by Cabot Corporation)-1 part of chromium-containing dye (Orient Chemical Co., Ltd.) -Product name: Bontron S-34)-3 parts of polypropylene wax (Product name: Hymer 660P, manufactured by Sanyo Kasei Kogyo Co., Ltd.) The above raw materials are dry-mixed with a super mixer and hot-melted and kneaded with a twin-screw extruder. After being obtained, the mixture was pulverized by a jet mill and classified by an airflow classifier to obtain a volume average particle size of 11
μm negatively chargeable toner particles were obtained. <Preparation of Toner Particle C>-100 parts of styrene-acrylate copolymer (trade name: CPR-120, manufactured by Mitsui Chemicals, Inc.)-80 parts of magnetite (trade name: EPT-500, manufactured by Toda Kogyo Co., Ltd.)-Chromium-containing Dye 2 parts (Orient Chemical Industry Co., Ltd. product name: Bontron S-34) ・ Polypropylene wax 5 parts (Sanyo Chemical Industry Co., Ltd. product name: Hymer 660P) The above materials are dry-mixed with a super mixer and then twin-screw extrusion kneader. After hot-melt kneading to obtain a kneaded product, the mixture was pulverized by a jet mill and classified by an air-flow classifier to have a volume average particle diameter of 11
μm negatively chargeable toner particles were obtained.

<Example 1> To 100 parts of the toner particles A, hydrophobic silica (trade name: R-
972) 0.5 parts and 0.3 parts of aluminosilicate particles (trade name: Lumonas SP-SA manufactured by Kao Corporation) were adhered to the surface of the toner particles using a Henschel mixer to obtain a toner for developing an electrostatic image of the present invention. . <Example 2> Hydrophobic silica (trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts of toner particles B.
5 parts and 0.3 parts of aluminosilicate particles (Lumonas SP-SA manufactured by Kao Corporation) were adhered to the surface of the toner particles by a Henschel mixer to obtain a toner for developing an electrostatic image of the present invention. <Example 3> Hydrophobic silica (trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts of toner particles C.
5 parts and 0.3 parts of aluminosilicate particles (Lumonas SP-SA manufactured by Kao Corporation) were adhered to the surface of the toner particles by a Henschel mixer to obtain a toner for developing an electrostatic image of the present invention. <Comparative Example 1> Hydrophobic silica (trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts of toner particles A.
Five parts were adhered to the surface of the toner particles by a Henschel mixer to obtain a comparative electrostatic image developing toner. <Comparative Example 2> Hydrophobic silica (trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts of toner particles B.
Five parts were adhered to the surface of the toner particles by a Henschel mixer to obtain a comparative electrostatic image developing toner. Comparative Example 3 Hydrophobic silica (trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts of toner particles C.
Five parts were adhered to the surface of the toner particles by a Henschel mixer to obtain a comparative electrostatic image developing toner. <Comparative Example 4> A comparative electrostatic image developing toner was obtained in the same manner as in Example 1, except that the aluminosilicate particles were changed to alumina (trade name: AKP3000, manufactured by Sumitomo Chemical Co., Ltd.).

<Evaluation Test 1: In case of two-component developing system>
A developer was prepared by mixing each of Examples 1 and 2 and Comparative Examples 1, 2, and 4 with a ferrite carrier at a ratio of 5:95, and a commercially available two-component developing type copying machine (copying speed A
(4:30 copies / min), 50,000 copies were made continuously, and the image characteristics before and after the copying were evaluated. Table 1 shows the results
Shown in

[Table 1] In Examples 1 and 2, there was no significant difference between before and after 50,000 copies, and good images were maintained. On the other hand, Comparative Examples 1 and 2 to which the aluminosilicate particles of the present invention were not attached
In both cases, after 50,000 copies, the image density was lower than in the initial stage, and a large number of black spots were generated on the photoreceptor due to toner adhesion, and appeared as black spots on the image. In Comparative Example 4 using conventional inorganic fine particles, the image density was lower than the initial stage, and the photoreceptor was shaved more. .

<Evaluation Test 2: Non-Magnetic One-Component Developing Method> Each toner of Example 2 and Comparative Example 2 was used.
Continuous printing of 5,000 sheets was performed using a commercially available non-magnetic one-component developing system printer (printing speed A4: 20 sheets / min), and the image characteristics before and after the printing were evaluated. Table 2 shows the results.

[Table 2] In Example 2, there was no significant difference in each characteristic before and after printing 5,000 sheets, and good image characteristics were maintained. On the other hand, in Comparative Example 2 in which the aluminosilicate particles of the present invention were not adhered, the toner component was fused on the developing roller after 5,000 sheets were copied, and vertical stripes were seen on the print, and fog was unacceptable. It got worse. In addition, many black spots were generated on the photoreceptor due to toner adhesion, and appeared as black spots on the image.

<Evaluation Test 3: In the case of the magnetic one-component developing system> A commercially available magnetic one-component developing system printer (print speed) was used for each of the toners of Example 3 and Comparative Example 3.
(A4: 16 sheets / min), 5,000 sheets were continuously printed, and the image characteristics before and after the printing were evaluated. Table 3 shows the results.

[Table 3] In substantially the same manner as in the evaluation test 2, in Example 3, before and after printing 5,000 sheets, no significant difference was observed in each characteristic, and good image characteristics were maintained. On the other hand, in Comparative Example 3 in which the aluminosilicate particles of the present invention were not adhered, the toner component was fused on the developing roller after 5,000 sheets were copied, and vertical stripes were seen on the print, and fog was unacceptable. It got worse. In addition, many black spots were generated on the photoreceptor due to toner adhesion, and appeared as black spots on the image.

<Evaluation Method> In each of the above evaluation tests, 50,000 sheets or 5,000 sheets of continuous copying were performed using an A4 size original having a black printing rate of 7% in an environment of a temperature of 20 ° C. and a humidity of 60% RH. The images obtained at the beginning and after continuous copying were evaluated. The evaluation method for each evaluation item is as follows. 1) Image density: Macbeth reflection densitometer (RD91
In 4), the density of the solid image was measured. 2) Fog: Colorimeter MODEM manufactured by Nippon Denshoku Industries Co., Ltd.
The whiteness of the non-image area before and after printing was measured with LZ1001DP, and the difference was indicated by the difference before and after printing. 3) Vertical streaks on prints: visually evaluated. ；: No black spot on print, ×: Black spot on print, XX;
There are noticeable black spots on the print. 4) Black spot on photoreceptor: Evaluated visually. ；: No black spot on photoconductor, ×: black spot on photoconductor. 5) Photoreceptor scraping: Measured with a micrometer (range that does not hinder practical use: 15 μm or less).

[0030]

According to the toner for developing an electrostatic image of the present invention, since aluminosilicate particles are adhered to the surface of the toner particles, filming of the toner on the surface of the carrier, the developing sleeve and the photoreceptor can be prevented, and This has the effect of reducing body surface shaving and stabilizing image quality when copying a large number of sheets. In particular, it works more effectively in a developing device having a recycling system.

Claims (4)

[Claims] 1. A binder resin and _{aM 2 O · bAl 2 O 3} · cSiO 2 · dR on the surface of the toner particles containing a colorant
mAn · yH ₂ O (where M is Na and / or K, R
Is 1 selected from the group consisting of Na, K, Ca, and Mg
A is CO ₃ , SO ₄ , NO ₃ , OH and Cl
One or more selected from the group consisting of: a is 1 to 6, b is 2
-8, c is 2-12, d is 0-4, m is 1-2, n is 1
, And y represents 0 to 32), wherein an aluminosilicate particle having a composition represented by the formula: 2. The electrostatic image developing toner according to claim 1, wherein 0.1 to 5.0 parts by weight of aluminosilicate particles are adhered to 100 parts by weight of the toner particles. 3. The electrostatic image developing toner according to claim 1, wherein the primary particles of the aluminosilicate particles according to claim 1 have a columnar shape, and the secondary particles have a tetrapod shape. 4. The electrostatic image developing toner according to claim 1, wherein the toner is used in a recycling system.