JP3268792B2 - toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner, which is held in a thin layer state on a surface of a cylindrical elastic roll in an electrophotographic developing process, and is conveyed by rotation of the elastic roll for development. For toner.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat.
Numerous methods have been proposed so far based on the Carlson process described in US Pat. In general, these form an electrostatic latent image on a latent image carrier using a photoconductive substance, and then selectively attach a coloring fine powder called “toner” to the latent image. The latent image is visualized. Further, the visualized toner image is transferred to a transfer material such as paper as necessary, and then fixed to the transfer material by heat, pressure, solvent vapor, or a combination thereof to obtain an image-formed product.

[0003] In general, as a developing method, a dry developing method,
The wet development method can be broadly classified. The dry development method includes a two-component development method using a toner and a toner carrier and a one-component development method using only a toner. As the two-component developing method, there are a magnetic brush developing method and a cascade developing method. As the one-component developing method, a jumping developing method, an FEED developing method, and a magnetic brush developing method are known. Generally, toners used in these developing methods include resin fine particles having a diameter of about 10 μm in which a colorant such as a dye or a pigment or a charge controlling agent is internally added, or a fluidization accelerator or the like is externally attached to the surface of the fine particles. It consists of something worn. In particular,
Examples of electrophotographic toners containing a metal complex salt compound as a charge control agent include JP-B-41-21153 and JP-B-4 Sho.
Nos. 3,179,555, JP-B-43-27596, JP-B-45-26478, JP-A-56-35142, and JP-A-57-141452 are known.

As a method for producing the above-mentioned toner, a kneading and pulverizing method, a suspension polymerization method and a spray drying method have been conventionally proposed, and the toner is generally produced by a kneading and pulverizing method. The kneading and pulverizing method comprises various steps of melt kneading, coarse pulverization, fine pulverization, classification, and external addition processing after a premixing step of raw material powders.

[0005]

In the developing process, in a developing method in which a developer is held in a thin layer state on a cylindrical elastic roll and conveyed by rotation of the elastic roll, a conventional one-component toner is used. Inevitably, the frequency of generation of weakly charged toner and toner charged to the opposite polarity is inevitably increased, so that the background of the non-printed portion and the bleeding of the printed image occur, and the adhesion force between the toner particles reaches a predetermined value. The non-control causes irregularities in the conveyance, and the resulting printed matter has a disadvantage of causing irregularities in the density.

[0006]

According to the present invention, there is provided a toner comprising:
A toner that is held in a thin layer state on the surface of a cylindrical elastic roll in an electrophotographic developing process, and is transported by rotation of the elastic roll and used for development. As essential components, a binder resin and a colorant are used. And a metal complex compound, wherein the sum of the acid value and the OH value of the binder resin is 30 mgKOH / g or more.

The present inventor has studied the factors that improve the charging characteristics of the toner.
It was found that by limiting the H value to a specific range, the solubility and compatibility of the charge control agent became good, and the charging characteristics were significantly improved by combination with the metal complex compound. Based on this, the present invention has been completed.

The toner according to the present invention is obtained by preliminarily mixing a binder resin, a colorant, and a metal complex compound, which are described later, by heating and kneading, pulverizing the mixture after cooling, and adjusting the particle size to a predetermined particle size by classification. Obtainable. When performing the heat kneading, a Banbury mixer may be used in a batch type, and a screw extruder or the like may be used in a continuous type.
For the pulverization, a cutter mill, an ong mill, a vibration mill, a ball mill, a jet mill, or the like is used. As a classification means, an airflow classifier, a vibrating screen or the like can be used.

The binder resin is not particularly limited except that the acid value and the OH value are limited to specific ranges, but a resin obtained by blending one or both of a thermoplastic resin and waxes is used. Can be used. For example, thermoplastic resins include polystyrene and copolymers, hydrogenated styrene resins, styrene / isobutylene copolymers, ABS resins, ASA resins, AS resins, AAS resins, ACS resins, AES resins, styrene
P-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene cross-linked polymer, styrene
Butadiene / hydrogenated paraffin copolymer, styrene / allyl / alcohol copolymer, styrene / butadiene rubber emulsion, styrene / maleic ester copolymer, styrene / isobutylene copolymer, styrene / maleic anhydride copolymer, acrylate Resin or methacrylate resin and its copolymer, styrene / acrylic resin and its copolymer, for example, styrene / acrylic copolymer, styrene / diethylamino / ethyl methacrylate copolymer, styrene / butadiene / acrylic acid Ester copolymer, styrene / methyl methacrylate copolymer, styrene / n-butyl methacrylate copolymer, styrene / diethylamino / ethyl methacrylate copolymer, styrene / methyl methacrylate / n-butyl acrylate Over preparative copolymer, styrene-methyl methacrylate-butyl acrylate-N-(ethoxymethyl) acrylamide copolymer, styrene-glycidyl methacrylate copolymer, a styrene-butadiene-dimethyl aminoethyl methacrylate copolymer,
Styrene / acrylate / maleate copolymer, styrene / methyl methacrylate / 2-ethylhexyl acrylate copolymer, styrene / n-butylarylate / ethyl glycol methacrylate copolymer, styrene / n-butylmeta Acrylate / acrylic acid copolymer, styrene / n-butyl methacrylate
Maleic anhydride copolymer, styrene / butyl acrylate / isobutyl maleic acid half ester / divinylbenzene copolymer, polyester and its copolymer, polyethylene and its copolymer, epoxy resin, silicone resin, polypropylene and its copolymer , Fluorine resin,
Polyamide resin, polyvinyl alcohol resin, polyurethane resin polyvinyl butyral resin, and the like, and one or a mixture of two or more of these can be used. Further usable waxes include candy lila wax, carnauba wax, plant-based natural wax such as rice wax, beeswax, animal-based natural wax such as lanolin, Montana wax, mineral-based natural wax such as ozokerite, paraffin wax,
Microcrystalline wax, natural petroleum wax such as petrolatum, polyethylene wax, synthetic hydrocarbon wax such as Fischer-Tropsch wax, montan wax derivative, modified wax such as paraffin wax derivative, hydrogenated wax such as hardened castor oil derivative,
Waxes such as synthetic waxes, higher fatty acids such as stearic acid and palmitic acid, polyolefins such as low molecular weight polyethylene, polyethylene oxide and polypropylene, ethylene / acrylic acid copolymers, ethylene / acrylic ester copolymers, ethylene / acetic acid Olefin copolymers such as vinyl copolymers, etc., one of these or
A blend of two or more types can be used.

In the present invention, a binder resin having a sum of an acid value and an OH value of 30 mg KOH / g or more is used as the above-mentioned binder resin. Further, the preferred range of the sum of the acid value and the OH value is 30 to 100 mgKOH / g, particularly preferably 40 to 80 mgKOH / g. By limiting the sum of the acid value and the OH value of the binder resin as described above, the charge amount of the binder resin itself increases and the solubility of the charge control agent increases, and further, the charge due to the addition effect of the metal complex compound described later A phenomenon is seen in which the charging characteristics are synergistically improved in combination with the uniformity of the charge. When the sum of the acid value and the OH value of the binder resin is less than 30 mgKOH / g, the charge amount of the binder resin itself decreases and the solubility of the charge control agent becomes insufficient, so that good charge characteristics, In particular, it is difficult to impart the effects of improving the uniformity of charge and the charge amount to the toner.

The coloring agents to be contained as toner components include black dyes or pigments such as carbon black, graphite, black titanium oxide, iron tetroxide, spirit black and nigrosine, phthalocyanine, rhodamine B lake, solar pure yellow 8G, Non-black dyes or pigments such as quinacridone, polytungstophosphoric acid, indaslen blue, and sulfonamide derivatives can be used.

Further, as the metal complex compound as a charge controlling agent, those having the following structures can be used. Specifically, for example, the following compound

[0013]

Embedded image In the formula, R ₁ represents an amino group, an acetylamino group, a sulfamide group, a sulfomethyl group, a benzoylamino group (including a substituted benzoylamino group), R ₂ represents a nitro group or a halogen atom, R ₃ represents a hydrogen atom, Represents a halogen atom, n represents 1 or 2, m represents an integer of 1 to 3, and n + m
Is less than or equal to 4 and M represents an iron or chromium atom. Can be synthesized and used.

Specifically, for example, the following compounds can be mentioned.

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[0017]

Embedded image In addition, a component obtained by subjecting the above metal complex compound to salt formation with an aliphatic amine (including a substituted aliphatic amine), an alicyclic amine or a heterocyclic amine by a conventional method can be used. Examples of the amine in this case include a compound represented by the following general formula.

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[0061]

Embedded image Further, in the present invention, the charge characteristics and the fluidity of the toner are further improved by additionally mixing a metal oxide having a polarity opposite to the polarity of the toner with the toner in a separated state. Can be.
The average particle diameter of such a metal oxide is preferably at least 1/10 of the average particle diameter of the toner and not more than the average particle diameter of the toner.

The toner as described above has an action similar to that of the carrier of the two-component toner, and is effective in applying a predetermined charge to the toner. However, unlike ordinary magnetic carriers, such metal oxides are developed and transferred simultaneously with the development of the toner,
It is preferable to limit the particle size to the above range. By satisfying the above conditions, the saturation speed of triboelectric charging is significantly increased, and the metal oxide acts as a solid lubricant to improve the flow characteristics of the toner. Is more effectively transported in a thin layer state.

Examples of the metal oxide having the opposite polarity to the toner described above include MgO, ZnO, PbO, Al ₂ O ₃ ,
Bi ₂ O ₃ , CdO, CuO, NiO, Ga ₂ O ₃ , M
nO ₂ , Fe ₂ O ₃ , GeO ₂ , Cr ₂ O ₃ , Fe ₃ O
₄ , GeO ₂ , SiO ₂ , TiO ₂ , SnO ₂ , Nb ₂
O ₅ , MoO ₃ , V ₂ O _{5, and the} like, but are not limited thereto. These metal oxides are preferably subjected to a hydrophobic treatment with a silane / titanate / aluminate coupling agent or the like.

In still another embodiment of the present invention, the toner has the same polarity as the toner, has a larger charging ability than that of the toner, and has an average particle diameter that is 1/10 of the average particle diameter of the toner. It is preferable to control the adhesive force between the toner particles in the range of 0.1 to 10 g / cm ² by externally attaching the following metal oxide to the surface of the toner particles. It is in the range of 5-5 g / cm ² . By fixing metal oxides of the same polarity on the toner surface in this manner, charge acceptability can be improved. In this case, by controlling the adhesive force between the toner particles within the range of 0.1 to 10 g / cm ^{2 under} the above-described conditions, the force required for attaching the thin layer of the toner to the elastic roll in the developing process is obtained. And thereby, the scattering of the toner can be effectively prevented. further,
By controlling the adhesive force in the range of 0.1 to 10 g / cm ² as described above, the cohesive force between the toners is further reduced, thereby further improving the thin layer transport characteristics of the toner in the developing process. Things.

Examples of metal oxides having the same polarity as the above toner include MgO, ZnO, PbO, Al ₂ O ₃ ,
Bi ₂ O ₃ , CdO, CuO, NiO, Ga ₂ O ₃ , M
nO ₂ , Fe ₂ O ₃ , GeO ₂ , Cr ₂ O ₃ , Fe ₃ O
₄ , GeO ₂ , SiO ₂ , TiO ₂ , SnO ₂ , Nb ₂
O ₅ , MoO ₃ , V ₂ O _{5, and the} like, but are not limited thereto. These metal oxides are preferably subjected to a hydrophobic treatment with a silane / titanate / aluminate coupling agent or the like.

With respect to the content of each of the above components, the preferred range of the metal oxide having the polarity opposite to that of the toner is 1 to 20% by weight, and the particularly preferred range is 2 to 10% by weight. Also,
The preferred range of the metal oxide having the same polarity as the toner is 0.1 to
The content is 5% by weight, and a particularly preferred range is 0.2 to 2% by weight.

In addition to the above components, the toner of the present invention may contain a dispersant, a magnetic powder, and the like, which are used as internal additives in general toners. As a dispersant, metal soap, polyethylene glycol, etc.
As magnetic powder, iron, cobalt, nickel, chromium, manganese metal powder, metal oxides such as chromium dioxide, iron sesquioxide, triiron tetroxide, ferrite, and alloys containing manganese and copper exhibit ferromagnetism by heat treatment An alloy or the like can be used.

[0068]

Embodiments of the present invention will be described below in detail. (Reference Example 1) 95 parts by weight of a polyester resin (acid value: 28.8, OH value: 24.8) Carbon black 3 parts by weight Metal complex salt 2 parts by weight was premixed with a powder mixer by a screw extruder. The mixture was heated and kneaded to obtain a kneaded product. Next, this was roughly pulverized by a rotoplex, further finely pulverized by a jet mill, and then subjected to airflow classification to obtain a powder having an average particle diameter of 10 μm, which was used as a toner base particle.

Next, in order to externally add a metal acid value having the same polarity as the toner, 100 parts by weight of the toner and 1.5 parts by weight of hydrophobic silica (particle diameter: 15 nm) are put into a Hertzel mixer and externally added. After that, a toner was obtained.

The above toner is charged into a one-component developing device,
When the charge amount of the toner was measured by a -SPART analyzer, the specific charge amount shown in the following table was obtained. The following table shows the toner adhesion obtained by the measurement with a powder bed tester. Further, when the apparatus was mounted on a laser printer having an organic photoreceptor to form an image, a clear image without background contamination was obtained with good reproducibility. (Comparative Example 1) 95 parts by weight of a styrene acrylic copolymer (acid value: less than 1, OH number: less than 1) 3 parts by weight of carbon black 2 parts by weight of a metal complex salt were premixed with a powder mixer, and a screw extruder was used. To obtain a kneaded product. Next, this was roughly pulverized by a rotoplex, further finely pulverized by a jet mill, and then subjected to airflow classification to obtain a powder having an average particle diameter of 10 μm, which was used as a toner base particle.

Next, in order to externally add a metal acid value having the same polarity as the toner, 100 parts by weight of the toner and 1.0 part by weight (particle diameter: 15 nm) of the hydrophobic silica are charged into a Henschel mixer, and the toner is uniformly mixed. Was attached. Further, 100 parts by weight of the toner and 5 parts by weight of a hydrophobic alumina (particle size: 3 μm) were charged into a Nauta mixer to interpose a metal acid value having a polarity opposite to that of the toner, to obtain a toner after mixing.

The above toner is charged into a one-component developing device,
When the charge amount of the toner was measured with a -SPART analyzer, a specific charge amount of -4.3 µC / g was obtained.
Further, when the apparatus was mounted on a laser printer having an organic photoreceptor to form an image, the non-printed portion was stained. (Reference Examples 2 to 5, Examples 2 and 3) Under the conditions of Table 1 below, toners were prepared in the same manner as in Reference Example 1, and the results shown in Table 1 below were obtained. (Comparative Examples 2 to 4) Under the conditions of Table 1 below, toner was prepared in the same manner as in Comparative Example 1, and the results shown in Table 1 below were obtained.

[0073]

[Table 1]

Claims (2)

(57) [Claims] Claims: 1. A toner for use in an electrophotographic development process, comprising a binder resin, a colorant, and a metal complex compound as essential components, wherein the sum of the acid value and the OH value of the binder resin is 30 mgKOH / g or more, a polarity opposite with the toner particles to a metal oxide mixed additionally while separated from the toner particles
Together with a metal oxide having a polarity, it has the same polarity as said toner particles have larger than that of the charging ability of the toner particles, and the average particle size is an average particle diameter of the toner particles The adhesive force between the toner particles is controlled in a range of 0.1 to 10 g / cm ² by externally attaching a metal oxide having a particle size of 1/10 or less to the surface of the toner particles. ,toner. 2. The toner according to claim 1, wherein said metal complex compound is a compound represented by the following general formula. Embedded image (Wherein, R ₁ represents an amino group, an acetylamino group, a sulfamide group, a sulfomethyl group, a benzoylamino group (including a substituted benzoylamino group), R ₂ represents a nitro group or a halogen atom, and R ₃ represents a hydrogen atom , A halogen atom, n is 1 or 2, m is an integer of 1 to 3, and n + m
Is less than or equal to 4 and M represents an iron or chromium atom. )