JPH04204855A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To form an image without scattering a toner or causing ground fog by kneading a resin compsn. contg. a specified binding resin, a specified electric charge controlling agent and a colorant, pulverizing and classifying the kneaded material. CONSTITUTION:A resin compsn. contg. binding resin granules of 0.5-1.5mm average diameter, an electric charge controlling agent of 2.0-4.0mum average particle size and a colorant is kneaded and this kneaded material is pulverized and classified to obtain a toner for developing an electrostatic charge image. Since the sizes of the binding resin and the electric charge controlling agent are regulated before kneading, the controlling agent is uniformly dispersed in the resin and mixed, the electric charge controlling property of the agent is improved and the electrostatic chargeability of the toner can be stabilized. The kick-off characteristics of electro-static charging are improved and an image is formed without scattering the toner or causing ground fog.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a toner for developing an electrostatic image used in an image forming apparatus such as an electrophotographic copying machine, and more specifically, the present invention relates to a toner for developing an electrostatic image that is used in an image forming apparatus such as an electrophotographic copying machine. The present invention relates to a toner for developing an electrostatic image that can form an image without causing scattering or background fog.

(Prior Art) In image forming apparatuses such as electrophotographic copying machines, a two-component developer containing fine toner particles and a carrier is generally used as a developer for visualizing an electrostatic latent image formed on a photoreceptor using a dry development method. developer is used. The fine particle toner is composed of a binder resin, a charge control agent, and additives such as a colorant.

Such a two-component developer is used after being uniformly mixed by stirring. By stirring, the toner is charged by friction with the carrier and adheres to the surface of the carrier.

The electrostatic latent image formed on the photoreceptor through the charging and exposure steps is developed with this toner. The obtained toner image is transferred to a support such as transfer paper, and then fixed onto the support by a fixing means. In this way, a copy of the original is obtained.

(Problem to be Solved by the Invention) By the way, in the process of manufacturing such toner, when the binder resin, charge control agent, colorant, etc. are mixed, kneaded, and pulverized, these materials segregate and cause a bridging phenomenon etc. in the upper part of the hopper. Therefore, there is a risk that uniform mixing and kneading may not be achieved. Since non-uniformity in the dispersion of the charge control agent tends to occur, the obtained toner has poor charge build-up properties and stability of distribution when it is tribo-electrified with the carrier, resulting in toner scattering and background fogging. However, the toner image formed by the dry development method has the disadvantage that the solid image portion is non-uniform. Further, there are problems in that the amount of spent carrier tends to increase and the life of the developer is short.

In connection with these problems, the following inventions have been proposed in the past.

■ Toner with stable chargeability made by fixing OCA particles to the surface of the toner (for example, JP-A-53-244055, JP-A-63-2)
44058).

■By separately adding carbon powder to coarse particle toner made by mixing, cross-polishing, and pulverizing resin, carbon, and dye, and uniformly mixing, pulverizing, and classifying the toner, it is effective for filming on organic photoreceptors. Toner with.

■By premixing, kneading, and pulverizing wax, carbon, and dye, adding resin and mixing with a Henschel mixer to form a toner, the molecular chains of the resin are prevented from being severed, making it resistant to off-setting. A toner with excellent toner properties.

However, methods ① to ② above have the disadvantage of decreasing productivity because the number of steps is extremely large, and they are still insufficient in terms of toner scattering, background fog, and uniformity of solid image areas. Ta.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to not only simplify the manufacturing process, but also to improve the stability of charging rise and eliminate toner scattering and background fog. An object of the present invention is to provide a toner for developing an electrostatic image that can form an image without any problems. Another object of the present invention is to provide a toner for developing electrostatic images that is less likely to become spent and has excellent uniformity and durability in solid areas.

(Means for Solving the Problems) The electrostatic image developing toner of the present invention has an average particle size of 0.5 to
Binder resin of 1.5mm, average particle size of 2.0~0μ
It is obtained by kneading a resin composition containing a charge control agent and a coloring agent, and pulverizing and classifying the kneaded product, thereby achieving the above object.

(Function) By setting the particle size of the binder resin and charge control agent within a predetermined range before mixing the binder resin, charge control agent, coloring agent, and other additives, the charge control agent is incorporated into the binder resin. As a result, charge controllability can be improved and charging properties can be stabilized.

In other words, when measuring the particle sizes of commercially available binder resins and charge control agents, their particle size distributions are wide. Even if the charge control agent is kneaded, it is unlikely that the charge control agent will be made into finer particles, so that the charge control agent with a coarse diameter and the charge control agent with a fine diameter will be ubiquitous in the obtained toner particles. In contrast, by aligning the particle sizes of the charge control agent and binder resin used in the present invention within a predetermined range before mixing them, the dispersibility of the charge control agent in the toner particles is improved. The charge control agent can be uniformly dispersed in the toner.

(Preferred Embodiment of the Invention) The binder resin used in the present invention is, for example, a thermosetting resin, a thermosetting resin in an uncured form, or a thermosetting resin in the form of an initial condensate, and has a melting point or softening point of 60 to 2°. Those within the OoC range are preferably used. Suitable examples include, but are not limited to, polystyrene, acrylic polymers, styrene-acrylic copolymers, chlorinated polyethylene, polypropylene, olefin polymers such as ionomers, homovinyl chloride, polyesters, polyamides, Various polymers such as polyurethane, epoxy resin, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl acetal resin such as polyvinyl butyral resin, phenol resin, rosin-modified phenol resin, xylene resin, rosin-modified maleic acid resin, rosin ester, petroleum resin, etc. can be given. These resins are arbitrarily selected depending on the fixing method and other required properties. Among these, polystyrene, acrylic polymers, or styrene-acrylic polymers are preferred, and styrene-acrylic polymers are particularly preferred, since they can easily control crushability and molecular weight distribution. These resins have a weight average molecular weight of 30.000
~200,000, especially 50.0
A range of 00 to 150.000 is preferred. One type of polymer or a mixture of two or more types may be used.

When the toner is a pressure fixable toner, it can easily be made of olefin polymers such as polyethylene, polypropylene, polyamide, etc. Preferably, it contains a polymer that undergoes sexual formation. This polymer may contain other polymers such as polyvinyl acetate, ethylene-vinyl acetate copolymer, hydrogenated polyethylene, hydrogen rosin ester, aliphatic, alicyclic or aromatic petroleum resins, etc. You may.

In the present invention, before mixing and kneading the binder resin with the charge control agent, the average particle size DS of the resin is determined using a crusher such as a bottle mill, a feather mill, a jet mill, and a classifier such as a wind classifier. @ is 1.0±0.51. The particle size of commercially available binder resins varies widely depending on the manufacturer, with some having a particle size of 51 square centimeters or more, and these may be used after being crushed and classified as described above.

A charge control agent may also be included to control the charge of the toner. Examples of charge control agents include oil-soluble dyes such as nigrosine dye, oil black, and soubiron black; naphthenic acid, salicylic acid, octylic acid, higher fatty acids, and resin acids such as manganese, iron, cobalt, nickel, lead, zinc, and cerium. , metal soaps that are metal salts such as calcium;
Metal-containing azo dyes; pyrimidine compounds; and metal chelates of alkyl salicylic acids are used. Among these, alcohol-soluble ones are particularly preferably used.

These charge control agents are used in an amount of 0 per 100 parts by weight of the binder resin.
．． 1 to 5 parts by weight is preferably used.

In the present invention, before mixing each of the charge control agents with the binder resin, the average particle size is
5@ is in the range of 3.0±1.0μ■. Since the average particle diameter D5B of a commercially available charge control agent is usually 1 to 10 μm, it may be used after being pulverized and classified as described above.

As the colorant contained in the toner, in addition to coloring pigments, any of various pigments conventionally used in toners, such as magnetic pigments and conductive pigments, can be used.

Suitable examples include, but are not limited to:

■Black pigments carbon black, acetylene black, lamp black, aniline black.

■Yellow pigments yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow,
Navel Yellow, Naphthol Yellow S1, Hansa Yellow 10G, Benzidine Yellow 61, Quinoline Yellow Lake, Permanent Yellow NGG, Tartrazine Lake.

■Orange pigments red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, palkan orange, indanthrene brilliant orange RK, benzidine orange G1 indanthrene brilliant orange G
K.

■Red pigments red pigments Red Garla, Cadmium Red, Red Lead, Mercury Cadmium Sulfide, Permanent Orange 4R, Pyrazolone Red, Lysole Red, Watching Red Calcium Salt, Lake Red D1 Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B1 Alizarin Lake, Brilliant Carmine B0 ■Purple pigment Manganese purple, First Violet B1 Methyl violet lake.

■Blue pigments navy blue, cobalt blue, American blue lake, Victoria blue lake, phthalocyanine blue, focused x phthalocyanine blue, partially chlorinated phthalocyanine blue, first sky blue, indanslen blue-B
C.

■Green pigment chrome green, chromium oxide, pigment green B1
Malachite Green Lake, Fanal Yellow Green G.

■White pigment Zinc white, titanium oxide, antimony white, zinc sulfide.

■Extender pigments perlite powder, barium carbonate, clay, silica, white carbon, talc, aluminum white.

0 Oil-based coloring dye ■ Inorganic dye ■ Magnetic pigment For example, triiron tetroxide, iron sesquioxide, zinc iron oxide, yttrium iron oxide, cadmium oxide, iron and steel oxide, iron oxide complex,
Iron neodymium oxide, iron barium oxide, iron manganese oxide,
Lanthanum iron oxide, iron powder, cobalt powder, nickel powder, etc. are known, and any of these known fine powders of magnetic materials can be used in the present invention.

These colorants may be used alone or in combination of two or more, and the amount in which a sufficient toner image density can be obtained is, for example, 5 to 15% by weight, particularly 7 to 12% by weight in the toner.

Further, the toner of the present invention may contain various additives known per se that are used in this field as shown below.

For example, an anti-offset agent can be added to the toner in order to further enhance the anti-offset effect. Examples of anti-offset agents include low molecular weight polyethylene,
Examples include various waxes such as low molecular weight polypropylene and paraffin wax; olefin polymers having 4 or more carbon atoms; fatty acid amides; silicone oils and the like. These anti-offset agents are preferably blended in an amount of 0.1 to 10 parts by weight, more preferably 1 to 8 parts by weight, per 100 parts by weight of the oil-soluble monomer.

To manufacture the toner of the present invention, first, the above-mentioned binder resin and charge control agent are preliminarily divided into average particles of the resin using a crusher such as a bottle mill, a feather mill, or a jet mill, and a classifier such as a wind classifier. The diameter I)ss is adjusted to be 1.0±0.5 mm, and the average particle diameter I)ss of the dye is adjusted to be within the range of 3.0±1.0 μm. Average particle size of binder resin and charge control agent I)s
When s is out of the above range, the mixing and kneading properties of the two deteriorate, resulting in a problem that the charge control agent is not uniformly dispersed in the binder resin. Next, after weighing the binder resin particles whose average particle size has been adjusted within a predetermined range and the charge control agent, other toner materials are mixed, and then a kneading machine such as a roll mill/axial kneading machine is used according to a conventional method. It can be obtained by melt-kneading using a pulverizer such as a jet mill, followed by pulverizing and classifying using a pulverizer such as a jet mill.

The toner of the present invention may also be blended with a fluidity modifier such as hydrophobic silica in an amount of 0.1 to 0.5% by weight per toner. Toner is obtained.

The toner of the present invention can be mixed with a magnetic carrier such as ferrite or iron powder as a two-component developer, or when the toner contains a magnetic pigment, can be used as a one-component developer to develop electrostatic latent images. used for.

(Effects of the Invention) According to the present invention, the charge control agent is uniformly dispersed in the resin, the charge control property is improved, and the stability of charge build-up is improved. It is possible to provide a toner which is capable of forming a toner with excellent uniformity and durability of solid areas, and which has less amount of spent.

(Example) Hereinafter, the present invention will be explained based on examples.

Fruit 1” Low styrene-acrylic resin (product name, Almatex PA
-525, manufactured by Mitsui Toatsu Chemical Co., Ltd.) was previously coarsely pulverized using a feather mill pulverizer. The particle size at this time is an average diameter of 0.9
It was 5gu+.

Next, an azo dye (trade name: Bontron 5-34, manufactured by Orient Kagaku Kogyo Co., Ltd.) was pulverized using a type I-2 dicut mill (manufactured by Nippon Ninimatic Co., Ltd.). Furthermore, the fine powder side was cut using a zigzag classifier (Alpine) so as to have a normal distribution. The particle size at this time is an average diameter of 3.
It was 2 μ■.

The following formulation was measured using the styrene-Agril resin and azo dye that had been subjected to the above-mentioned pre-pulverization and classification treatment.

Styrene acrylic resin 100 parts by weight Azo dye 1.2 parts by weight Carbon black (Printex, Degussa) 8.5 parts by weight Polypropylene wax (Viscol 5sop, manufactured by Kochu Kasei Co., Ltd.) 1.5 parts by weight The above formulation was applied to Henschel. Blend using Kimisar (FM20B, Mitsui Miike Engineering Co., Ltd.) at 1500r.
Uniform mixing and dispersion of the materials was performed by rotating at p+g.

Next, this mixture was kneaded with a twin-screw kneader (PCM30, Ikegai Iron Works), finely pulverized with an I-2 type Zikoto mill pulverizer (manufactured by Nippon Ichikomatic Co., Ltd.), and the pulverized product was mixed with an air classifier (
Classified by Albine classifier (Albine Co., Ltd.) and particle size is 5 to 2.
A toner of 0μ straw was obtained.

This toner and carrier are manufactured by Powder Chick Co., Ltd. (F1).
41-1530), toner and carrier were placed in a wide cylindrical polyethylene bottle and mixed (toner concentration: 4%) to obtain a developer.

No uneven accumulation or bridging phenomenon in the cross-conductor material hopper was observed in the pretreated mixed product. Moreover, the extrusion amount was also stable.

When the dispersion sealing layer of toner without pre-pulverization treatment was compared using the preparation method, a clear difference was observed in the dispersion of dye particles.

L Tatsucho main styrene-acrylic resin (product name, Heimercho B-10
00, manufactured by Kochu Kasei Kogyo Co., Ltd.) was previously coarsely pulverized using a Feather Mill pulverizer. The particle size at this time is the average diameter (1,62
It was mm.

Next, azo dye (product name, Subironbura, RiTRH1)
Zigzag classifier (made by Albine)
The coarsely crushed side and the finely crushed side were cut to have a normal distribution. The particle size at this time was an average diameter of 2°2μ.

The following formulation was measured using the pre-pulverized styrene-acrylic resin and azo dye.

Styrene acrylic resin 100 parts by weight Azo dye 1.5 parts by weight Carbon black (Printex, Degussa) 8.5 parts by weight Polypropylene wax (Viscol 550P, manufactured by Kochu Kasei Co., Ltd.) 1.5 parts by weight Blend using a thermometer (FM20B, Mitsui Miike Engineering Co., Ltd.) at 1200 r.
Uniform mixing and dispersion of the materials was performed by rotating the tube at a constant speed.

Next, this mixture was kneaded with a twin-screw kneader (PCM30, Ikegai Iron Works), finely pulverized with an l-2ffi digital mill pulverizer (manufactured by Nippon Pneumatic Co., Ltd.), and the pulverized material was mixed with a wind classifier (Albine Classifier). The toner particles were classified using a ``grader'' (Albine Co., Ltd.) to obtain a toner having a particle size of 5 to 20 .mu.m.

This toner and carrier (MFC-4) manufactured by T-Kai Co., Ltd. were used, and the toner and carrier were placed in a wide cylindrical polyethylene bottle and mixed (toner concentration: 9%) to obtain a developer.

Styrene-acrylic resin (trade name: FB-862, manufactured by Mitsubishi Rayon ■) was previously coarsely pulverized using a feather mill pulverizer. The particle size at this time was an average diameter of 0.53 mm.

Next, an azo dye (trade name: Bondron T-77, manufactured by Orient Kagaku Kogyo Co., Ltd.) was pulverized using a type I-2 dicut mill (manufactured by Nippon Ichi Nematic Co., Ltd.). Furthermore, the fine powder side was cut using a zigzag classifier (Alpine) so as to have a normal distribution. The particle size at this time is an average diameter of 3.
It was a 9μ turtle.

The following formulation was weighed using the styrene-acrylic resin and azo dye that had been subjected to the above-mentioned pre-pulverization and classification treatment.

Styrene acrylic resin 100 parts by weight Azo dye 1.0 parts by weight Carbon black (Regal 400R, manufactured by Cabot Corporation) 8.5 parts by weight Polypropylene wax (Viscol 5sop, manufactured by Kochu Kasei Co., Ltd.) 1.5 parts by weight Henschel Blend using Kimisar (FM20B, Mitsui Miike Engineering Co., Ltd.) at 1500r.
By rotating at p■, uniform mixing and dispersion of the materials was performed.

Next, this mixture was kneaded with a twin-screw kneader (PCM30. Ikegai Iron Works), and! - Finely pulverize with a 2-type jet mill (manufactured by Nippon Ichi Niematic Co., Ltd.), and classify this pulverized product with an air classifier (Alpine classifier, Alpine Co., Ltd.) with a particle size of 5 to 5.
20 μl of toner was obtained.

This toner and carrier are manufactured by Powder Chick (FL).
41-1530), toner and carrier were placed in a wide cylindrical polyethylene bottle and mixed (toner concentration: 4.5%) to obtain a developer.

Shiphen Goto styrene-acrylic resin (product name, Almatex XP
A-3420. (manufactured by Mitsui Toatsu Chemical Co., Ltd.) was previously coarsely pulverized using a Feather Mill pulverizer. The particle size at this time is an average diameter of 1
．． It was 38mm.

Next, an azo dye (trade name: Bontron 5-32, manufactured by Orient Kagaku Kogyo Co., Ltd.) was pulverized using a type I-2 dicut mill (manufactured by Nippon Ichi Mumatic Co., Ltd.). Furthermore, the fine powder side was cut using a zigzag classifier (Alpine) so as to have a normal distribution. The particle size at this time is an average diameter of 2.
It was 5μ■.

The following formulation was weighed using the styrene-acrylic resin and azo dye that had been subjected to the above-mentioned pre-pulverization and classification treatment.

Styrene acrylic resin 100 parts by weight Azo dye 1.5 parts by weight Carbon black (Mitsubishi MA-100, manufactured by Mitsubishi Chemical Industries, Ltd.) 8.5 parts by weight Polypropylene wax (Viscol 550P, manufactured by Kochu Kasei Co., Ltd.) 1.5 parts by weight The above formulation was blended using Henschel Kimisar (FM20B, Mitsui Miike Engineering Co., Ltd.), and 1200 r.
The materials were uniformly mixed and dispersed by rotating at pm.

Next, this mixture was mixed with a twin-screw kneader (PCM30, Ikegai Iron Works), finely pulverized with an I-2 type jet mill t11 (manufactured by Nippon Pneumatic Co., Ltd.), and this pulverized material was mixed with a wind classifier (Alpine Classifier). The particle size is 5.
~20μ proverbial toner was obtained.

As this toner and carrier, Powder Te, manufactured by Risha (F1)
41-1530), toner and carrier were placed in a wide cylindrical polyethylene bottle and mixed (toner concentration: 4.5%) to obtain a developer.

Shiraokadan styrene-acrylic resin (product name, Almatex XP
A-3516 (manufactured by Mitsui Toatsu Chemical Co., Ltd.) was previously coarsely pulverized using a feather mill pulverizer. The particle size at this time is an average diameter of 1
．． It was 48mm.

Next, an azo dye (trade name: Bontron 5-34, manufactured by Orient Chemical Industry Co., Ltd.) was pulverized using a type I-2 dicut mill (manufactured by Nippon Pneumatic Co., Ltd.). Furthermore, the fine powder side was cut using a zigzag classifier (Albine) so as to have a normal distribution. The particle size at this time is an average diameter of 3.
It was 8 μ■.

The following formulation was weighed using the styrene-acrylic resin and azo dye that had been subjected to the above-mentioned pre-pulverization and classification treatment.

Styrene acrylic resin 100 parts by weight Azo dye 1.0 parts by weight Carbon black (Printex 90, manufactured by Degussa) 8.5 parts by weight Polypropylene wax (Viscol 550P, manufactured by Kochu Kasei) 1.5 parts by weight The above formulation A toner having a particle size of 5 to 20 .mu.m was obtained by processing using the same processing equipment as in Example Particles 1.

This toner and carrier are manufactured by Powder Chick Co., Ltd. (F1).
4L-1530), toner and carrier were placed in a wide cylindrical polyethylene bottle and mixed (toner concentration: 4.5%) to obtain a developer.

The following formulation was measured using a commercially available styrene-acrylic resin and an azo dye that had not been crushed or classified.

Styrene acrylic resin (Altex PA-525, manufactured by Mitsui Toatsu Chemical Co., Ltd.) 100 parts by weight Azo dye (Bontron 5-34, manufactured by Orient Chemical Industry Co., Ltd.) 1.2 parts by weight Carbon black (Printex 90, manufactured by Degussa Corporation) )
8.5 parts by weight of polypropylene wax (Viscol 5sop, manufactured by Kochu Kasei Co., Ltd.) 1.5 parts by weight The above formulation was processed using the same processing equipment as Example Particle 1 to obtain a toner having a particle size of 5 to 20 μI.

This toner and carrier are manufactured by Powder Chick Co., Ltd. (F1).
41-1530), toner and carrier were placed in a wide round polyethylene bottle and mixed (toner concentration: 4.5%) to obtain a developer.

Next, the developers obtained in Examples 1 to 5 and Comparative Examples above were pre-aged in an aging device for 10 hours, and then this developer was heated at Sanda Kogyo in an environment of 35°C and 85% RH. (1) The image was printed on 10,000 sheets using a DC-111 copying machine made by Co., Ltd., and the following items were evaluated.

The results are shown in Table 1.

Dispersibility of dye particles: 1 mg of the obtained toner was placed on a preparation plate, heated at 150° C. to melt it, and then a cover glass was placed on top of the molten toner and pressure was applied to prepare a sample. This sample was observed under an electron microscope to confirm the state of dispersion of the dye, and was evaluated in the following two stages.

○: Dye is uniformly dispersed.

X: Dye aggregates are observed.

Fog density = Fog density when copying 10,000 sheets was measured using an image densitometer (manufactured by Tokyo Electric Co., Ltd., TC-6D).

Toner scattering: The interior of the copying machine was visually evaluated after copying 10,000 sheets.

(Here is a clue) From the results in Table 1, it is clear that by aligning the particle sizes of the dye and binder resin within a predetermined range before mixing the two, the charging build-up characteristics can be improved and toner scattering and background fogging can be avoided. It was confirmed by 8fi that an image can be formed without any trouble.

that's all

Claims (1)

[Claims] 1. A resin composition containing a binder resin with an average particle size of 0.5 to 1.5 mm, a charge control agent with an average particle size of 2.0 to 4.0 μm, and a colorant is kneaded, A toner for developing electrostatic images obtained by pulverizing and classifying a kneaded material.