JPH04156550A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To improve the dispersibility of fine grains and the fluidity of a toner and obtain good picture quality over a long period by using resin fine grains processed with a silane coupling agent having an amino group. CONSTITUTION:A toner for developing an electrostatic charge image contains toner powder and resin fine grains having an average grain size smaller than the average grain size of the toner powder, and the resin fine grains are processed with a silane coupling agent having an amino group. Thermoplastic resin or thermosetting resin in the form of unhardened resin or an initial condensate having the melting point or softening point in the range 60-200 deg.C, for example, is used for the binding resin used in the toner powder. A polystyrene acryl polymer or a styrene acryl polymer is preferable because of crushability and the simplicity on molecular weight distribution control, and the styrene acryl polymer is more preferable in particular.

Description

Detailed Description of the Invention (Industrial Field of Application) 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, and more specifically to a toner for developing an electrostatic image that has excellent fluidity. Regarding developing toner.

(Prior Art) In an image forming apparatus such as an electrophotographic copying machine, a binder resin and a coloring agent are generally added as a developer for visualizing an electrostatic latent image formed on a photoreceptor using a dry development method. A two-component developer is used, which includes a toner and a carrier.

Such a two-component developer is used after being uniformly mixed by stirring. Due to the 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.

In such a magnetic brush development method using a two-component developer containing a toner and a carrier, the toner needs to have good fluidity in order to perform development well.

By the way, as a toner that prevents a decrease in image density and an increase in fog, JP-A-60-186854 discloses a toner powder and a fine powder (soap-free) having an average particle diameter smaller than the average particle diameter of the toner powder. A toner for developing an electrostatic image containing a toner (obtained by a polymerization method) has been proposed.

(Problems to be Solved by the Invention) The above-mentioned toner has the disadvantage that the fine powder has poor dispersibility and is prone to agglomeration, and furthermore, the resulting toner has poor fluidity, resulting in poor image quality as copying is performed. This had the disadvantage of causing a decrease in

In particular, in the case of positively chargeable toner containing a positive charge control agent, the charge control agent often has hydrophilic properties, which further reduces the fluidity of the toner, making it impossible to obtain good image quality. Furthermore, when a charge control agent and a juglone dye were used, there were drawbacks of easy deterioration and lack of stability.

The present invention solves the above-mentioned drawbacks, and its purpose is to improve the dispersibility of fine particles and the fluidity of toner, thereby making it possible to form good image quality over a long period of time. An object of the present invention is to provide a toner for developing electrostatic images. Another object of the present invention is to provide a positively chargeable toner with excellent stability.

Means for Solving the Problems) The toner for developing electrostatic images of the present invention contains toner powder and fine resin particles having an average particle size smaller than the average particle size of the toner powder. The fine particles are treated with a silane coupling agent having an amine group,
Thereby, the above objective is achieved.

(Function) Since the resin fine particles used in the toner for developing electrostatic images of the present invention are treated with the above-mentioned amine group-containing silane coupling agent, the fluidity of the resin fine particles is improved. It is uniformly dispersed with the toner powder, improving the fluidity of the toner. In addition, resin fine particles whose surface is treated with a silane coupling agent having an amine group have strong positive chargeability and high humidity stability. Thus, a toner having a certain property can be obtained.

(Suitability of the invention) As the powder toner used in the present invention, a known toner conventionally used in a dry development method is used, and additives such as a colorant and a charge control agent are added to the binder resin. It is a dispersed powder toner. Such toner powder can be produced by a conventionally known method, such as a pulverization method in which each toner material is melt-kneaded, then pulverized and classified, or It can be obtained by a legal method (for example, suspension polymerization method, dispersion polymerization method, etc.).

The binder resin used in the toner powder is, for example, a thermosetting resin or a thermosetting resin in uncured form or in the form of an initial condensate, with a melting point or softening point in the range of 60 to 200'C. things are used. Suitable examples include, but are not limited to, polystyrene, acrylic polymers, styrene-acrylic copolymers, chlorinated polyethylene, polypropylene, olefin polymers such as ionomers, polyvinyl chloride, polyesters, polyamides, 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 Various polymers such as These resins are arbitrarily selected depending on the fixing method and other required properties. Among these, because it is easy to control the crushability and molecular weight distribution,
Polystyrene, acrylic polymers or styrene-acrylic polymers are preferred, and styrene-acrylic polymers are particularly preferred. These resins have a weight average molecular weight of 30.0
00 to 200,000, particularly 50
,000 to 150.000 is preferred. One type of polymer or a mixture of two or more types may be used.

When the toner powder used is a pressure fixing toner,
It is preferable to contain a secondary reflex polymer such as polyethylene or polypropylene, or a polymer that easily undergoes W-like deformation such as polyamide. 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.

Examples of the charge control agent include oil-soluble dyes such as nigronon dye, oil black, and spiron blasok;
Metal soaps, which are metal salts of naphthenic acid, salicylic acid, octylic acid, fatty acids, and resin acids such as manganese, iron, cobalt, nickel, lead, zinc, cerium, and calcium, or metal-containing ab dyes, pyrimidine compounds, and metal alkyl salicylates. Examples include chelate, binder resin 100
0.1 to 5 parts per part by weight are preferably used.

As the pigment, 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 pigment Channel wall rack, furless wall rack, iron black.

Yellow pigment yellow lead, zinc content, cadmium yellow, yellow iron oxide, mineral first yellow, nickel yellow, nickel titanium yellow, Fujiburus yellow, Teftol yellow 31, Hansa yellow 10G.

Benzidine Yellow G1, Quinoline Yellow, Permanent Nyro NGG, Tartrazine Lake.

Orange pigment red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK.

Red pigment red pigment Red Garla, Cadmium Red, Red Lead, Mercury Cadmium Sulfide, Permanent Orange 4R, Lysole Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brillia Cytocarmine 6B, Eosin Lake, Rhodamine Lake 81, Alizarin Lake,
Brilliant Carmino 3B0 Purple Pigment Manganese Purple, Fast Buy Reno L-B, Methyl Violet Lake.

Blue pigments navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalo/anine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated product, first sky blue, indanthrenblue-BC
o Green pigment chrome green, chromium oxide, pigment green B,
Malachite Green Lake, Final Yellow Green G0 White pigment titanium dioxide (titanium white), zinc white.

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

Examples of magnetic material pigments include triiron tetroxide, iron sesquioxide, zinc iron oxide, yttrium iron oxide, cadmium oxide, iron and steel oxide, iron oxide complex, neodymium iron oxide, barium iron oxide, iron manganese oxide, and lanthanum iron oxide. , iron powder, cobalt powder, nickel powder, etc., and any of these known fine powders of magnetic materials can be used in the present invention.

These pigments may have multiple functions. For example, carbon black has the functions of a black pigment and a conductive pigment. Similarly, iron black (magnetite) has the functions of a black pigment and a magnetic pigment.

These colorants are used singly or in combination of two or more, and the amount to obtain a sufficient toner image is, for example,
It is preferably present in the toner in an amount of 5 to 15% by weight, especially 7 to 12% by weight.

Further, the toner powder may contain an anti-offset agent to prevent the toner powder from adhering to the fixing roller. For example, various animal and plant waxes, polyethylene wax, polypropylene wax, etc. are used as the anti-offset agent, and these are generally added to the toner powder at a concentration of 1%.
It is blended in an amount of ~5% by weight.

The method for manufacturing toner powder in the present invention is similar to the conventional toner manufacturing process, so it will not be described in detail. The particle size of the obtained toner powder is preferably 5 to 30 μm, particularly 5 to J
5 μm is preferred.

The resin fine particles used in the present invention are resin fine particles having a smaller average particle size than the average particle size of the toner powder described above. Examples of the resin constituting the resin fine particles include acrylic resin, acrylic-urethane resin, and the like. The average particle diameter of the resin fine particles is preferably O,OS to 5 μm, more preferably 0.1 to 4 μm. Particularly preferred are acrylic fine particles having an average particle size of 0.1 to 4 μm obtained by dispersion polymerization, emulsion polymerization, soap-free polymerization, and pulverization methods.

These fine resin particles are treated with a silane coupling agent having 7 amine groups, and examples of the silane coupling agents having amine groups include N-β (aminoethyl) γ-amine propyltrimethoxine, N-β(
aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-
Examples include diallylaminopropyltrimethoxysilane, and at least one of these coupling agents is selected.

The amount of the amine group-containing silane coupling agent to be treated is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight based on the resin fine particles. Ami 7
If the treatment amount of the silane coupling agent having a group is less than 0.1% by weight, the effect of improving the fluidity of the resin fine particles, the dispersibility of the resin fine particles, and the fluidity of the toner will be reduced. If the amount is more than % by weight, the fluidity of the resin particles tends to decrease.

Processing the silane coupling agent having an amino group into fine particles can be carried out using various conventionally known methods and devices. For example, a solution of the silane coupling agent having an amine group dissolved in a solvent The fine resin particles may be immersed in the solution or a solution may be applied to the fine resin particles, followed by drying.

The toner of the present invention may also contain a fluidity modifier such as hydrophobic silica in an amount of 0.1 to 0.5% by weight per toner. The toner according to the present invention is obtained by sprinkling the property improver in a mixer.

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 fluidity of the fine particles is improved by treating the fine particles with a silane coupling agent having an amine group, thereby improving the dispersibility and improving the fluidity of the toner. can do.

Therefore, it is possible to provide an electrostatic image developing toner that can form a good image with little variation in image quality and has excellent durability without deterioration in development characteristics such as a decrease in the amount of charge. Further, it is possible to provide a toner having good positive chargeability even when used under high humidity.

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

Point 1" mouth = 100 parts by weight of styrene/n-butyl acrylate copolymer Carbon black (manufactured by Mitsubishi Kasei Co., Ltd., #44) 10 parts by weight of charge control agent (manufactured by Daiichi Noendo Kagaku Co., Ltd., Bontron N-0
1) 5 parts by weight polypropylene (
Biscol 660P (manufactured by Mitsubishi Kasei Corporation) Double Satobe After melt-kneading the mixture consisting of the above formulation, it was pulverized using a jet mill and classified to obtain an average particle size of 11.0μ.
m toner powder was obtained.

Meanwhile, methyl methacrylate (50) was placed in a four-bottle flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube.
0 parts by weight, 0.3 parts by weight of potassium persulfate, and 0.3 parts by weight of polyvinyl alcohol, and the reaction was carried out at 80''C in a nitrogen stream for 4 hours. After the polymerization was completed, centrifugation, washing with water, and drying were performed. Acrylic fine particles with an average particle size of 0.2 μm were obtained.

Acrylic fine particles obtained above 100 parts by weight N-β (
3 parts by weight of γ-aminopropyltrimethoxy/ran (manufactured by Shin-Etsu Chemical Co., Ltd., KBE 603) 50 parts by weight of methanol A treated fine powder was obtained.

100 parts by weight of the toner powder, 0.3 parts by weight of treated fine powder, and hydrophobic silica (Nippon Aerosil?!, R972)
A toner was obtained by mixing and stirring 0.2 parts by weight using a Hennel mixer.

A developer was prepared by mixing 4 parts by weight of this toner with 96 parts by weight of a ferrite carrier having an average particle size of 80μ, and this developer was loaded into a modified Sanda Kogyo IDc-2055 machine (temperature: 35°C). 50,000 images were printed in an environment of 80% humidity. The results are shown in Table 1.

γ-aminopropyltriethquinsilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE 903) instead of 3 parts by weight of N-β (aminoethyl) γ-aminopropyltrimethoxine silane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE 603) Except that 3 parts by weight was used.
A toner was obtained in the same manner as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are also shown in Table 1.

A toner was obtained in the same manner as in Example 1, except that the treated fine powder was not used. The obtained toner was evaluated in the same manner as in Example 1. The results are also shown in Table 1.

A toner was obtained in the same manner as in Example 1, except that the untreated acrylic fine particles obtained in Example 1 were used instead of the treated fine powder. The obtained toner was evaluated in the same manner as in Example 1. The results are also shown in Table 1.

3 parts by weight of vinyltriethoxysilane (KBE 1003, manufactured by Shin-Etsu Chemical Co., Ltd.) instead of 3 parts by weight of ΔTakumi N-β (amine ethyl) γ-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE 603) A toner was obtained in the same manner as in Example 1 except for using the following. The obtained toner was evaluated in the same manner as in Example 1.

The results are also shown in Table 1.

(Left below) From the results in Table 1, it can be seen that when no treated fine powder is used (Comparative Example 1)
), the image density (1, D) and fog density (F, D,) increased after printing 50,000 sheets, and even when untreated fine resin powder was used (Comparative Example 2), the image density (1, D) and fog density (F, D,) increased. Fog density after printing (
F, D,) are increasing.

Further, even when resin fine particles treated with a silicone coupling agent having no amine group are used, their properties are insufficient. On the other hand, in this example, it was confirmed that the image density and image characteristics were all satisfactory.

that's all

Claims (1)

[Scope of Claims] 1. A toner for developing an electrostatic image, comprising a toner powder and fine resin particles having an average particle size smaller than the average particle size of the toner powder, the fine resin particles comprising: A toner for developing electrostatic images that is treated with a silane coupling agent having an amino group.