JPH10282724A - Toner for developing electrostatic charge image and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure practical negative chargeability and to obtain a toner for developing an electrostatic charge image excellent in stability of a charged state, environmental stability and durability by allowing carbon black to exist as a negative charge controlling agent in the surface parts of toner particles. SOLUTION: This toner contains a bonding and/or fixing material and a negative charge controlling agent, and carbon black exists as the negative charge controlling agent only in the surface parts of the toner particles or exists in the surface parts and interiors of the toner particles so that the carbon black content of the surface parts is made higher than that of the interiors. When carbon black exists only in the surface parts of the toner particles, it is preferably contained by 0.01-20 wt.% of the total amt. of the toner particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image using carbon black as a negative charge control agent, which is used for developing an electrostatic latent image in electrophotography, electrostatic printing, and the like. Further, the present invention relates to a method for producing a toner for developing an electrostatic charge image having improved negative chargeability using carbon black.

[0002]

2. Description of the Related Art In a copying machine or the like utilizing an electrophotographic method, a binder resin and a colored resin are used to develop an electrostatic latent image formed on a photoreceptor having a photosensitive layer containing a photoconductive substance. Various toners having an agent and the like are used.
Such toners are required to have sufficient performance in terms of chargeability, fixability, non-offset properties, durability, and the like.

In a system for developing an electrostatic latent image, chargeability is a particularly important factor. Therefore, in order to appropriately control the chargeability of the toner, a charge control agent having a positive charge or a negative charge is often added to the toner. As charge control agents that have been put to practical use, azo-based metal complexes and salicylic acid-based metal complexes are mainly used for imparting negative frictional charge to toner. However, many of these are thermally and chemically unstable, and may be decomposed by mechanical or electrical impact. Also,
These charge control agents are relatively expensive.

[0004] On the other hand, the use of carbon black for coloring as a coloring agent for black toner has already been widely performed. As an example, a toner containing a specific furnace carbon black (Japanese Patent Laid-Open No. 50-80137), a toner containing a carbon black whose surface is oxidized with ozone and having improved dispersibility, and a polyester resin. (For example, JP-A-3-200158 and JP-A-8-6293).

On the other hand, with respect to the chargeability of carbon black, for example, Japanese Patent Publication No. 51-33471 discloses that a carbon black subjected to a wet oxidation treatment is contained in a toner so that a positively chargeable toner can be used without using a charge control agent. Is obtained. JP-A-56-1627
No. 54 describes a difference in triboelectricity due to a difference in the amount of active hydrogen on the surface of carbon black. That is, as the amount of active hydrogen approaches 0, the positive chargeability generally increases, and as the amount of active hydrogen increases, the chargeability becomes negative. Therefore, it is described that the charge amount of the toner can be stabilized by using carbon black according to the purpose of the toner. However, in the toner described in the above publication, an azo-based metal complex dye is used to impart a desired charge.

[0006]

As described in the above publications, carbon black as a coloring agent is
Generally, they are dispersed as uniformly as possible in the toner.
When carbon black is uniformly dispersed in the toner particles, sufficient triboelectric charging cannot be imparted to the toner, as shown in Comparative Examples below. Therefore, without the positive or negative charge control agent, the frictional charging property of the toner becomes unstable, the charge distribution becomes broad, and a weakly charged toner or a reversely charged toner is generated, so that fogging and scattering of the toner are likely to occur.

However, it would be advantageous in many respects if this thermally and chemically stable carbon black could be used as a charge control agent for controlling or stabilizing the charge amount of the toner.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object the use of carbon black to attain a practical level of chargeability. It is an object of the present invention to provide a method for producing a toner for developing an electrostatic image, which has improved negative chargeability by using a toner for developing a charge image and carbon black.

[0009]

The toner for developing an electrostatic image of the present invention which achieves the above object is a toner for developing an electrostatic image comprising a binding and / or fixing material and a charge control agent. The carbon black is unevenly distributed as a negative charge control agent on the surface of the toner particles (claim 1).

The binding and / or fixing material is used for holding other toner components and fixing the toner to an image forming object such as paper or a plastic film. Binding and fixing are usually performed with the same material, but two or more types of materials that mainly or exclusively bind, materials that mainly or exclusively fix, and materials that perform both binding and fixing are used. They can be used in combination. That is, usually, a material called a binder resin that performs both binding and fixing is used as a binding and / or fixing material. For example, the outer shell of the toner particles is subjected to heat or pressure to form an image forming object. It is formed of a material having good fixability by heat melting or pressure for fixing toner particles to an object, and the inside of the toner particles is relatively hardly deformed by heat melting or pressure (for example, a rubber-based material or the like). (A synthetic resin having a high melting temperature). In the latter case, the material forming the outer shell of the toner particles may be one that performs both binding and fixing. The outer and inner shells of the toner particles may be formed of different materials that perform both binding and fixing.

The fact that carbon black is unevenly distributed as a negative charge control agent on the surface of the toner particles means that the carbon black exists only on the surface of the toner particles (claim 2) or that the carbon black is present on the surface of the toner particles. And in the case where the weight ratio of carbon black at the surface portion is higher than the weight ratio of carbon black at the surface portion. The term “inside” means a portion of the toner particles that is inside the surface. The weight ratio of carbon black on the surface portion means the ratio of the weight of carbon black to the total weight on the surface portion of the toner particles, and the weight ratio of carbon black on the inside means the total weight inside the toner particles. It means the ratio of the weight of carbon black to the weight.

When the carbon black is present only on the surface of the toner particles, the carbon black is used in an amount of 0.01 to 2%.
It is preferable that the amount of carbon black is 0% by weight, that is, the ratio of the weight of carbon black existing only on the surface of the toner particles to the total amount of the toner particles is 0.01 to 20% (claim 3).

When carbon black is present on the surface and inside of the toner particles, the carbon black must be present in an amount of 0.01 to 20% by weight on the surface of the toner particles, that is, present on the surface of the toner particles. Preferably, the weight ratio of the carbon black to the total toner particles is 0.2 to 20%.

In the case where carbon black is present on the surface and inside of the toner particles, the weight ratio of carbon black inside is preferably 20% or more lower than the weight ratio of carbon black on the surface portion. It is possible that carbon black is unevenly distributed on the surface portion of (Claim 6). In this case, for example, if the weight ratio of carbon black on the surface is 10% by weight, the weight ratio of carbon black on the inside is 8% by weight or less.

The toner for developing an electrostatic image may be colored with a coloring agent other than carbon black. As a coloring agent other than carbon black, for example, coloring agents such as various chromatic pigments or coloring agents such as black or other achromatic pigments can be used. Further, in the toner for developing an electrostatic image, carbon black fine particles and / or fine particles containing carbon black are fixed to the surface portion of the base particle, so that the carbon black becomes negatively charged on the surface portion of the toner particle. (Claim 8).

As the carbon black fine particles, general carbon black fine particles can be used. As the fine particles containing carbon black, for example, fine particles containing carbon black fine particles in a binder and / or a fixing material (for example, a binder resin or a fixing resin) or fine particles of grafted carbon black may be used. Can be.

The state in which the fine particles are fixed on the surface of the base particles may be, for example, a weight average particle diameter of preferably 1 μm or less, for example, 10 nm to 1 μm by a laser light scattering method.
μm fine particles adhered to the surface of a base particle having a weight average particle diameter of preferably 5 to 20 μm by a laser light scattering method, partially buried in the surface portion of the base particle having the above size, and There is a state where the whole is buried in the surface portion of the mother particle having a size. For example, when the fine particles cover almost the entire surface of the base particles, the fine particles may partially or partially cover the surface of the base particles. Further, as an example of a state in which the fine particles are fixed to the surface portion of the base particle, an outer peripheral portion of the base particle is formed by carbon black and another component such as a binder and / or a fixing material (for example, a binder resin or a fixing resin). In which a film-like, shell-like or layer-like surface portion is formed.

In this case, the carbon black fine particles and / or the fine particles containing the carbon black can be fixed to the surface of the base particles by mechanical and thermal energy mainly comprising an impact force. Item 9).

Further, the toner for developing an electrostatic image is provided with an outer shell portion in which toner particles are bound on the outer peripheral side of the base particles and the carbon black is bound and / or held by a fixing material. The base particles may be made of a material that does not melt at a temperature equal to or lower than the melting temperature of the binding and / or fixing material forming the outer shell (claim 10). When the toner is fixed to the image forming object by thermal melting, if the heat fixing temperature is between the melting temperature of the binding and / or fixing material forming the outer shell and the melting temperature of the base particles, The toner can be fixed while preventing melting.

As described above, the toner for developing an electrostatic image in which the carbon black fine particles and / or the fine particles containing carbon black are fixed to the surface portion of the base particles,
The base particles may contain carbon black (claim 11). In this case, the carbon black contained in the base particles usually functions as a colorant. Further, the base particles may be colored with a coloring agent other than carbon black, for example, a coloring agent such as various chromatic pigments or dyes, or a coloring agent such as black or other achromatic pigments or dyes. (Claim 12).

In the toner for developing an electrostatic image of the present invention, the surface portion of the toner particles in which carbon black is unevenly distributed is a portion of a distance between the surface and the center of the toner particles of 20% or less from the surface. (Claim 13). It is preferable that the surface portion of the toner particles in which carbon black is unevenly distributed is a portion at a distance of 10% or less from the surface between the surface and the center of the toner particles. More preferably, 5% from the surface between the surface and the center of the toner particles.
It is the part of the following distance. The surface portion of the toner particles where carbon black is unevenly distributed may be thinner, for example, a portion between the surface and the center of the toner particle, which is at a distance of 0.2% or less from the surface. Good. 50n
m.

Next, the method for producing a toner for developing an electrostatic image with improved negative chargeability according to the present invention is a method for producing a toner for developing an electrostatic image comprising a binding and / or fixing material and a charge control agent. Wherein carbon black is unevenly distributed on the surface of the toner particles (claim 14).

[0023]

Industrial Applicability The toner for developing an electrostatic image of the present invention has a practical level of negative charging property due to carbon black, and is excellent in charging stability, environmental stability and durability. In addition, the toner for developing an electrostatic charge image of the present invention can be provided at a relatively low cost because carbon black used as a charge control agent can be obtained at a lower cost than a conventional charge control agent. It is also useful as a paint.

According to the method of the present invention for producing a toner for developing an electrostatic image with improved negative chargeability, the carbon black is unevenly distributed on the surface of the toner particles, thereby sufficiently improving the negative chargeability of the toner particles. Can be.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In a first embodiment of the present invention, fine particles of a resin for toner are used as base particles (I), and carbon black as a negative charge control agent is formed on the entire surface of the base particles (I). Is a black toner prepared by fixing the toner uniformly.

In the present invention, the fixing of the carbon black fine particles and / or the fine particles containing carbon black to the surface of the base particles is carried out, for example, by using a powder surface reforming apparatus, by mechanical and thermal treatment mainly based on impact force. It is preferably performed by the use of energy. As a specific example of the powder surface reforming apparatus, a hybridizer (NHS-1 type, manufactured by Nara Machinery Co., Ltd.) can be mentioned. Immobilization of carbon black fine particles and / or fine particles containing carbon black by the hybridizer is performed, for example,
Styrene-acrylic resin powder as a base particle (particle size: about 1
0 μm), 0.01 to 1 part by weight of carbon black (for example, carbon black MA-100 manufactured by Mitsubishi Chemical Corporation, primary particle size: 22 nm) is added to 100 parts by weight, and 16 parts by weight is added.
This can be done by stirring at 000 rpm for about 3 minutes.

In a second embodiment of the present invention, resin fine particles (II) containing carbon black and having a weight average particle diameter of about 1 μm or less as measured by a laser light scattering method and carbon black fine particles are used as the base particles ( This is a black toner prepared by fixing to the entire surface portion of I). The fixation of the fine particles to the base particles (I) can be performed using a hybridizer as a powder surface modifying device as described above.
In this case, it is possible to form an outer shell formed by holding carbon black with a resin on the outer peripheral side of the base particles (I).

Fine particles or resin particles (II) containing carbon black are mixed with carbon black (for example, carbon black # 4 manufactured by Mitsubishi Chemical Corporation) per 100 parts by weight of a resin for toner (for example, styrene-acrylic resin).
4) 50 parts were mixed, and the mixture was melt-kneaded using a kneader such as a heating roll or a kneader. After cooling the kneaded material, the mixture was coarsely pulverized. It can be prepared by finely pulverizing to about 5 to 1 μm.

In the third embodiment of the present invention, the base resin (I) is a colored resin fine powder (II) having an average particle size of about 10 μm.
(I), wherein the toner has carbon black fine particles and / or fine particles containing carbon black fixed on the surface thereof.

The above-mentioned colored resin fine powder (III) is mixed with a coloring agent (for example, carbon black MA100 manufactured by Mitsubishi Chemical Corporation, an organic pigment, an oil-soluble dye) per 100 parts by weight of a resin for toner (for example, styrene-acrylic resin). 1 to 10 parts), melt-kneading the mixture using a kneading machine such as a heating roll or a kneader, cooling the kneaded product, coarsely pulverizing it, and further jetting. It can be prepared by finely pulverizing to a particle size of about 5 to 20 μm using a pulverizer.

The fourth embodiment of the present invention is a toner in which fine particles obtained by coating carbon black with a second binder resin are fixed on the surface of the above-mentioned base particles (I). The fixation of the fine particles to the base particles (I) can be performed using a hybridizer as a powder surface modifying device as described above. In this case, it is possible to form an outer shell formed by holding carbon black with a resin on the outer peripheral side of the base particles (I).

The coating treatment of carbon black is, for example,
A solution obtained by dissolving and dispersing carbon black and a second binder resin in an appropriate solvent (for example, xylene, trichloroethylene, methylene chloride, etc.) can be carried out by spray-drying. Fine particles coated with the above binder resin are obtained.

In the second and fourth embodiments,
In the case where the toner is fixed to the image forming object by thermal melting, and in the case where the base particles are made of a material that does not melt at the temperature at the time of thermal fixing, the resin containing carbon black and the second binder resin are respectively thermally fixed. It is necessary to be able to fix the image forming target at the temperature at the time. In this case, by coloring the base particles with carbon black or another coloring agent, it is possible to obtain a toner image having excellent resolution.

The form of the base particles (I) in the present invention is not particularly limited, and may be the fine powder of the resin for a toner, the fine powder of a colored resin (III), or the toner powder obtained by a known toner manufacturing method. You may.

The method for producing the base particles (I) includes, for example, a dry method in which a toner material is kneaded, pulverized and classified to obtain colored particles having a constant particle size; a monomer material in a solvent; and, if necessary, charge control. Wet method of dispersing agents and waxes to obtain colored particles of desired particle size by emulsion polymerization method, suspension polymerization method, solution polymerization method, aggregation method, etc .; dyeing resin particles dispersed in solvent with dye And the like.

The toner for developing an electrostatic image of the present invention, for example, can be treated as described above to cause carbon black to be unevenly distributed as a negative charge control agent on the surface of the toner particles. The toner can exhibit a practical level of triboelectrification by sufficiently exerting its negative charge imparting function. The obtained toner may be subjected to a modification treatment with inorganic fine particles such as silicon oxide and titanium oxide, if necessary.

In the present invention, commercially available carbon black for coloring can be used as carbon black as a negative charge controlling agent and, in some cases, a coloring agent.

Examples of carbon black that can be used include # 10B, # 20B, # 30, and # 3 manufactured by Mitsubishi Chemical Corporation.
3, # 40, # 44, # 45, # 45L, # 50, # 5
5, # 95, # 260, # 900, # 1000, # 22
00B, # 2300, # 2350, # 2400B, # 2
650, # 2700, # 4000B, CF9, MA8,
MA11, MA77, MA100, MA220, MA2
30, MA600, MCF88, etc .; Monarch 120, Monarch 700, Monarch 800, Monarch 880, Monarch 1000, Monarch 1100, manufactured by Cabot Corporation
Monarch 1300, Monarch 1400, Mogal L, Legal 99R, Legal 250R, Legal 300R,
Legal 330R, Legal 400R, Legal 500
R and Regal 660R, etc .; PRINTEX A, PRINTEX G, PRINTEX U, PRINTEX V, PRINTEX 55, PRINTEX 14 manufactured by Degussa
0U, PRINTEX 140V, Special Black 4, Special Black 4A, Special Black 5,
Special black 6, special black 100, special black 250, color black FW1, color black FW2, color black FW2V, color black FW18, color black FW200, color black S150, color black S160, and color black S170.

The type of carbon black used is not particularly limited. Any of acidic carbon black, neutral carbon black and basic carbon black can be used.

The acidic carbon black is, for example, MA8, MA100, 2200B, 2400B from Mitsubishi Chemical Corporation.
Degussa color black FW20
0, color black FW18, color black S15
0, color black S160, color black S17
0, PRINTEX U, PRINTEX 1400, Cabot Corporation under the trade names Monarch 1300, Mogal L, Regal 400R, COLOMBIAN CARBON under the trade names Raven 1200, Raven 1220, Raven 1250. I have.

Neutral or basic carbon black is, for example, # 33, # 40, # 45, # 45 from Mitsubishi Chemical Corporation.
L, # 10B, # 4000B, # 2300, # 240
0, # 900 brand name from Tegusa, PRINTEX 35, PRINTEX 60, PRINTEX 30
0, a brand name of color furnace such as PRINTEX A.
The brand name of oil furnace such as 0R, Legal SR, etc.
Raven 40, CONDU from Columbian Carbon
It is commercially available under the trade names of CTEXSC and MOLACCOLS.

In the present invention, MA8, MA100, # 2400 manufactured by Mitsubishi Chemical Co., Ltd.
B: Degussa Color Black FW200, Special Black S160; Cabot Monarch 13
00, Mogar L; Raven 1200 and 1250 manufactured by Columbian Carbon Co., Ltd .; and oxidized products thereof, and oxidized products of neutral or basic carbon black can be suitably used.

This type of acidic carbon black is
In general, since the blackness is excellent, it is advantageous as a coloring agent. The particle size of carbon black is about 1 μm or less,
For example, fine particles having a diameter of 10 nm to 1 μm are preferable. This is because it is suitable for fixing carbon black on the surface of the base particles and imparting a necessary charge amount to the toner. Needless to say, even when basic carbon black is used, a practically usable negatively chargeable toner can be obtained (for example, Example 11).

On the other hand, as the binding and / or fixing material used in the toner of the present invention, the following known resins for toner can be exemplified. That is, styrene resin, acrylic resin, methacrylic resin, styrene-
Acrylic resin, styrene-methacrylic resin, butadiene resin, styrene-butadiene resin, styrene-maleic acid resin, styrene-vinyl methyl ether resin, styrene-methacrylic acid ester copolymer, polyvinyl alcohol resin, polyester resin, epoxy resin, Polyurethane resin, polyamide resin, phenol resin, polypropylene resin, paraffin wax and the like. These resins can be used alone or as a blend of several types.

In general, the resin for toner as a binder and / or fixing material includes heat of the resin from the viewpoints of fixing property of the toner to paper, non-offset property to a roller, and blocking resistance during storage of the toner. Melting characteristics, elasticity, fluidity, etc. are required. As such a resin, for example,
Acrylic resins, styrene-acrylic resins, styrene-methacrylic acid ester copolymers, polyester resins, and the like can be suitably used. These are appropriately used so as to match the embodiment of the present invention.

Preferred materials for forming the base particles of the toner particles include styrene-based, acrylic-based, styrene-acryl-based, styrene-methacrylate-based, polyester-based, polyamide-based thermoplastic resin powders, polyester-based resins, and the like. An epoxy-based or polyurethane-based thermosetting resin powder can be used.

The particle size of the base particles is, for example, 5 to 20 μm,
Preferably, it can be about 10 μm. 20 μm
Exceeds 5 μm, it is difficult to achieve fine line reproducibility of the copied image.
If it is less than 30, the surface area for fixing the carbon black fine particles and / or the fine particles containing the carbon black around the base particles becomes small, so that sufficient negative charge property may not be easily imparted to the toner.

Resin particles containing carbon black (I
Examples of the resin that can be used for preparing I) and the colored resin fine powder (III) include thermoplastic resins or thermosetting resins for toner as described above, or various vinyl resins for preparing by a polymerization method. And the like.

The second binder resin for coating the carbon black fine particles may be a thermoplastic resin which is soluble in a solvent and has a fixing property, or a resin for coating the carbon black by a polymerization method. Include various vinyl monomers for grafting.

For coloring the resin, carbon black for coloring (black for color) is usually used. As such carbon black, for example, MA100, MA11, MA8, MA7, # 40, # 4 manufactured by Mitsubishi Chemical Corporation
4: Raven 1250 manufactured by Columbian Carbon Co .; Monarch 880, Mogal L, Mogal 660R manufactured by Cabot; Color Black FW2, Special Black 250, Printtex 90 manufactured by Degussa, etc. may be used. it can.

Further, if necessary, a large number of known dyes and pigments can be used. Specific examples thereof include quinophthalone yellow, hansa yellow, isoindolinone yellow, perinone orange, perylene maroon, rhodamine 6G lake, quinacridone, anthuanthrone red, rose bengal, copper phthalocyanine blue and copper phthalocyanine green, and diketopyrrolopyrrole. And organic pigments such as titanium white, titanium yellow, ultramarine, cobalt blue, and red iron oxide. Preferred pigments for obtaining a black toner in combination with carbon black are phthalocyanine dyes and pigments, but toners of other colors can also be prepared using these dyes and pigments.

In order to improve the quality of the toner, additives such as an anti-offset agent, a fluidity improver, and a cleaning aid can be added internally or externally.

Examples of the anti-offset agent (release agent) used for improving the fixing property include known various waxes, in particular, polyolefin waxes such as low molecular weight polypropylene, polyethylene, oxidized polypropylene and oxidized polyethylene; Natural waxes such as Uba wax, rice wax, and montan type wax can be used.

As the fluidity modifier, various metal oxides such as silica, aluminum oxide and titanium oxide, and magnesium fluoride can be used.

As the cleaning aid, metal soaps such as stearic acid; various synthetic resin fine particles such as fluorine-based, silicone-based, and styrene- (meth) acryl-based synthetic resin fine particles can be used.

In addition, depending on the form of development using the toner of the present invention, a conductive substance (for example, conductive carbon black,
Graphite), magnetic fine particles (for example, known ferromagnetic fine particles such as iron, cobalt, nickel, and other ferromagnetic metals, various alloys, and oxides thereof such as ferrite) can be added to the toner. it can.

When the toner of the present invention is used as a two-component developer, the toner of the present invention can be mixed with a carrier powder and developed by a two-component magnetic brush developing method or the like.

As the carrier, all known carriers can be used. For example, a particle size of 50 to 200 μm
m of iron powder, nickel powder, ferrite powder, glass beads, and the like, and the surface thereof is an acrylate copolymer, a styrene-acrylate copolymer, a styrene-methacrylate copolymer, a silicone resin, or a polyamide. Examples thereof include those coated with a resin, a fluoroethylene-based resin, and the like.

When the toner of the present invention is used as a one-component developer, when producing the toner as described above,
For example, a fine powder made of a ferromagnetic material such as iron powder, nickel powder, and ferrite powder can be added and dispersed for use. Examples of the developing method in this case include a contact developing method and a jumping developing method.

Examples of the preferred form of the developer for the toner of the present invention include a two-component toner, a non-magnetic one-component toner, and a non-magnetic one-component toner which can be developed by a magnetic brush developing method.
Insulating magnetic toner can be used. As a fixing method for fixing the toner of the present invention to an image forming object, heat roll fixing or pressure fixing can be performed by appropriately selecting the form of the toner and the resin for the toner.

[0061]

Next, the toner for developing an electrostatic image of the present invention will be described in more detail by way of examples. In the following description, “parts by weight” is abbreviated as “parts”.

Example 1 ( Example of First Embodiment) Carbon black MA8 (pH = 3.0) 1 manufactured by Mitsubishi Chemical Corporation was added to 100 parts of styrene-acrylic resin powder (particle diameter: about 10 μm).
Section and add a hybridizer (Nara Machinery Works NHS-
By stirring (1 min. At 16000 rpm) for 3 minutes, a black toner having carbon black fixed to the surface of the resin powder was obtained.

2.5 g of this toner and 50 g of iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) were placed in a polyethylene container, and the mixture was stirred at 150 rpm for 10 minutes using a ball mill turntable. Was measured under the conditions of 25 ± 1 ° C. and 50 to 60 RH (relative humidity), and the triboelectric charge amount of this toner was −33.
It was 7 μC / g.

Examples 2 to 10 (Examples of First Embodiment) Toners were prepared in the same manner as in Example 1 except that the carbon black in Example 1 was replaced with the carbon black shown in Table 1, respectively. The charge amount was measured in the same manner as in Example 1. Table 1 shows the measurement results including those of Example 1.

[0065]

[Table 1] Table 2 shows the physicochemical properties of carbon black in each of the examples shown in Table 1.

[0066]

[Table 2] Example 11 ( Example of Second Embodiment) 100 parts of styrene-acryl resin was mixed with 50 parts of carbon black # 44 (pH = 8.0) manufactured by Mitsubishi Chemical Corporation,
The mixture was melt-kneaded using a heating roll. After cooling the kneaded product, it was coarsely pulverized and further finely pulverized using a jet pulverizer to obtain black resin particles (II) of 0.5 to 1 μm.

10 parts of the black resin particles (II) and the same resin powder (I) of styrene-acrylic resin (particle size: 7)
To 8 μm) in a Henschel mixer at 2,000 rpm for 2 minutes. Then, 0.5 part of carbon black # 44 was further added, and the mixture was similarly stirred for 1 minute.

The thus obtained product is treated with a hybridizer (NHS-1 type, Nara Machinery Co., Ltd.), so that the surface of the resin powder (I) has black resin particles (II) and carbon black. A black toner having # 44 fixed was obtained.

An iron powder carrier (TEFV200 / 300, manufactured by PowderTech) was added to 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. The initial blow-off charge of this developer was -20.6 μC / g. The initial blow-off charge of the developer at low temperature and low humidity (10 ° C., 30% RH) and high temperature and high humidity (35 ° C., 80% RH) are −21.1 μC / g and −20.
It was very stable at 0 μC / g.

Further, when repeatedly photographed using this developer, the charge rising property, the charge stability and the sustainability were good, the image density was stable even at the initial stage and after continuous copying, and there was no fog. A good black image was obtained.

Example 12 ( Example of Second Embodiment) Polyester resin (HP-31 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
3) To 100 parts, 50 parts of carbon black MA8 (pH = 3.0) manufactured by Mitsubishi Chemical Corporation was mixed and melt-kneaded using a hot roll. After cooling the kneaded material, it is coarsely pulverized,
Further, it is finely pulverized by using a jet pulverizer to obtain 0.5 to 1
μm black resin particles (II) were obtained.

10 parts of the black resin particles (II) and resin powder (I) of the same polyester resin (particle diameter 7 to 8)
90 μm) in a Henschel mixer at 200 rpm.
The mixture was stirred and mixed at 0 rpm for 2 minutes. On the other hand, another 0.5
Parts of carbon black MA8 were added, and the mixture was similarly stirred for 1 minute.

The thus obtained product is treated with a hybridizer (NHS-1 type, Nara Machinery Co., Ltd.), so that the surface of the resin powder (I) has black resin particles (II) and carbon black. A black toner having MA8 fixed was obtained.

Iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) was applied to 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. Using this developer, a copy test was performed with a commercially available copying machine, and a high-quality image was obtained in the same manner as in Example 11.

Example 13 ( Example of Third Embodiment) Styrene-acrylic resin (Hymer SM manufactured by Sanyo Chemical Co., Ltd.)
B600) and 100 parts of Mitsubishi Chemical Corporation's carbon black MA100 (pH = 3.0) were mixed and melt-kneaded using a heating roll. After cooling the kneaded product, it was coarsely pulverized and further finely pulverized using a jet pulverizer to obtain a black resin fine powder (III) having a particle size of about 10 μm.

To 100 parts of the black resin fine powder (III),
One part of the same carbon black as above was added, and the mixture was stirred with a hybridizer (NHS-1 type, Nara Machinery Works) (1600).
0 rpm for 3 minutes) to obtain a black resin powder (II
A black toner having carbon black MA100 fixed on the surface of I) was obtained.

An iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) was used for 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. A copy test was performed using a commercially available copying machine using this developer.
A high quality image was obtained in the same manner as in the above.

Example 14 ( Example of Third Embodiment) Carbon black MA100 was replaced with OIL Yellow 127 (8 parts) manufactured by Orient Chemical Industries, Ltd., and treated in the same manner as in Example 13 to obtain a particle size of about 10 μm. Yellow resin fine powder (III)
I got

To 100 parts of the yellow resin fine powder (III), 0.3 part of carbon black MA8 was added, and the mixture was treated with a hybridizer (Nara Machinery Co., Ltd., NHS-1 type) to obtain the yellow resin fine powder (III). A toner having carbon black MA8 fixed on the surface was obtained.

Iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) was applied to 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. When a copying test was performed using a commercially available copying machine using this developer, a high-quality yellow image was obtained.

Example 15 Yellow resin fine powder (III) 1 obtained in Example 14
To 00 parts, 0.05 part of carbon black # 2400B was added, and the same process as in Example 14 was performed to obtain a toner having carbon black # 2400B fixed on the surface.

Iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) was applied to 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. When a copying test was performed using a commercially available copying machine using this developer, a high-quality yellow image was obtained.

Example 16 ( Example of Third Embodiment) Carbon black MA100 was replaced with OIL RED 308 (8 parts) manufactured by Orient Chemical Industry Co., Ltd., and treated in the same manner as in Example 13 to obtain a particle size of about 10 μm. Red resin fine powder (III) was obtained.

To 100 parts of this red resin fine powder (III), carbon black MA8 (0.3 part) was added, and the mixture was treated with a hybridizer (Nara Machinery Co., Ltd., NHS-1 type) to obtain red resin fine powder (III). To obtain a toner having carbon black MA8 fixed on the surface thereof.

An iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) was applied to 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. When a copying test was performed using a commercially available copying machine using this developer, a high-quality red image was obtained.

Example 17 ( Example of Third Embodiment) Carbon black MA100 was replaced with VALIFAST BLUE2606 (8 parts) manufactured by Orient Chemical Industry Co., Ltd., and treated in the same manner as in Example 13 to obtain a particle having a particle size of about 10 μm. Blue resin fine powder (II
I) was obtained.

Carbon black MA8 (0.3 parts) was added to 100 parts of the blue resin fine powder (III), and the mixture was treated with a hybridizer (Nara Machinery Co., Ltd., NHS-1 type) to give the blue resin fine powder (III). To obtain a toner having carbon black MA8 fixed on the surface thereof.

An iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) was used for 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. When a copying test was performed using a commercially available copying machine using this developer, a high-quality blue image was obtained.

Example 18 ( Example of Fourth Embodiment) 95 parts of powder obtained by drying and coagulating styrene-butadiene rubber, and 5 parts of carbon black (Carbon Black # 45L manufactured by Mitsubishi Chemical Corporation) Was mixed with a Henschel mixer and then melt-kneaded with a heating roll. After cooling the kneaded product, it was coarsely pulverized and further finely pulverized using a jet pulverizer to obtain black resin fine powder (III) having a particle size of about 10 μm, that is, mother particles.

On the other hand, as a material constituting an outer shell provided around the mother particles, 100 parts of a polyester resin (HP-313 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used and oxidized carbon black-2 used in Example 9 was used. Of 50 parts,
This mixture was melt-kneaded using a hot roll. After cooling the kneaded product, it was coarsely pulverized and further finely pulverized using a jet pulverizer to obtain 0.5 to 1 μm black resin particles (II).

Next, 90 parts (base particles) of black resin fine powder (III) and 10 parts of black resin particles (II) were stirred and mixed in a Henschel mixer at 2000 rpm for 3 minutes.

The thus obtained product is treated with a hybridizer (NHS-1 type, Nara Machinery Co., Ltd.), whereby the black resin particles (II) are fixed on the surface of the black resin powder (III). The obtained black toner was obtained.

An iron powder carrier (TEFV200 / 300, manufactured by Powder Tech) was used for 5 parts of the obtained toner.
Five parts were mixed to prepare a developer. When a copying test was performed using a commercially available copying machine using this developer, an image having excellent fine line reproducibility was obtained.

Comparative Example 1 100 parts of the same styrene-acrylic resin as in Example 1
Part of Mitsubishi Chemical Corporation carbon black # 40 was melt-kneaded at 120 ° C. using a heating roll, cooled, pulverized,
By classifying, a toner having an average particle size of 10 μm was obtained.

When the charge amount of this toner was measured in the same manner as in Example 1, it was -7 μC / g.

Comparative Example 2 100 parts of the same styrene-acryl resin as in Example 1 and 5
Parts of carbon black MA100 manufactured by Mitsubishi Chemical Co., Ltd. were melt-kneaded at 120 ° C. using a heating roll, cooled, pulverized and classified to obtain a toner having an average particle diameter of 10 μm.

When the charge amount of this toner was measured in the same manner as in Example 1, it was -6.1 μC / g.

Comparative Example 3 100 parts of the same styrene-acryl resin as in Example 1 and 20 parts of carbon black MA100 manufactured by Mitsubishi Chemical Corporation were used.
The mixture was melt-kneaded at 120 ° C. using a heating roll, cooled, pulverized, and classified to obtain a toner having an average particle diameter of 10 μm.

When the charge amount of this toner was measured in the same manner as in Example 1, it was -4.3 μC / g.

Comparative Example 4 The charge amount of the styrene-acrylic resin (average particle size: 10 μm) used in Example 1 and Comparative Examples 1, 2, and 3 was measured in Example 1.
As a result, the charge was -7.2 μC / g, and the charge amount hardly changed. Thereby, Comparative Example 1
It has been confirmed that in a uniformly dispersed carbon black-containing toner such as that described in Tochi 3, when the amount of carbon black is increased, the charge amount tends to decrease due to its conductivity.

Claims (14)

[Claims] 1. An electrostatic image developing toner comprising a binding and / or fixing material and a charge control agent, wherein carbon black is unevenly distributed as a negative charge control agent on the surface of toner particles. Characteristic toner for developing electrostatic images. 2. The toner according to claim 1, wherein the carbon black is present only on the surface of the toner particles. 3. The toner for developing an electrostatic image according to claim 2, wherein the toner contains 0.01 to 20% by weight of carbon black. 4. The toner for developing an electrostatic image according to claim 1, wherein carbon black is present on the surface and inside of the toner particles, and the weight ratio of carbon black on the surface is higher than the weight ratio of carbon black on the inside. . 5. The electrostatic image developing toner according to claim 4, wherein carbon black is present in an amount of 0.2 to 20% by weight on the surface of the toner particles. 6. The weight ratio of carbon black in the inside to the weight ratio of carbon black in the surface portion is 20%.
The toner for developing an electrostatic charge image according to claim 4, wherein the toner is at least 30%. 7. The electrostatic image developing toner according to claim 1, which is colored with a coloring agent other than carbon black. 8. The toner according to claim 1, wherein the carbon black particles and / or the fine particles containing carbon black are fixed on the surface of the base particles so that the carbon black is unevenly distributed as a negative charge control agent on the surface of the toner particles. An electrostatic image developing toner. 9. The electrostatic image development according to claim 8, wherein the carbon black fine particles and / or the fine particles containing carbon black are fixed to the surface of the base particles by mechanical and thermal energy mainly comprising impact force. For toner. 10. An outer shell portion in which toner particles are provided with carbon black bound and / or held by a fixing material on the outer peripheral side of the base particles. 9. A material which does not melt below the melting temperature of the binding and / or fixing material forming the shell.
Or a toner for developing an electrostatic image according to item 9. 11. The toner for developing an electrostatic image according to claim 8, wherein the base particles contain carbon black. 12. The electrostatic image developing toner according to claim 8, wherein the base particles are colored with a coloring agent other than carbon black. 13. A toner according to claim 1, wherein the surface portion of the toner particles in which the carbon black is unevenly distributed is a portion of a distance between the surface and the center of the toner particle of 20% or less from the surface.
The toner for developing an electrostatic image according to 4, 5, 6, 7, 8, 9, 10, 11, or 12. 14. A method for producing a toner for developing an electrostatic image, comprising a binding and / or fixing material and a charge controlling agent, wherein carbon black is unevenly distributed on the surface of the toner particles. A method for producing a toner for developing an electrostatic image with improved negative chargeability.