JPH03223872A - Toner for electrophotography - Google Patents

Abstract

PURPOSE:To obtain the toner which is fast in rising and has a uniform electrostatic chargeability by fixing the fine particles of a surface treating agent onto the toner surface. CONSTITUTION:The surface treating agent 2 is stuck to the surface of a toner particle 1 and a mechanical impact is applied thereto to immobilize the surface treating agent 2. The surface treating agent 2 is exemplified by oxides, such as silicone oxide, titanium oxide, and aluminum oxide, and carbides, such as silicon carbide, titanium carbide, and boron carbide in the case of inorg. matter, and dyes and pigments of a nigrosine system, azo system, etc., and resins, such as polymethyl methacrylate, polyvinylidene fluoride and silicone resin in the case of org. matter. The toner which is fast in rising and has the good stability with lapse of time and the high electrostatic chargeability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field 1] The present invention relates to an electrophotographic toner used for electrophotographic development, and in particular to an electrophotographic toner that has a quick charge build-up and good stability over time. This invention relates to toner for electrophotography.

[Prior Art 1] Toner used in electrophotography, in various developing methods, is required to have a quick start-up at the start of the apparatus and to have stable and uniform chargeability over time. Therefore, methods have been adopted in which a charge control agent is contained in the toner or a charge control agent is attached to the surface of the toner particles.

[Problems to be Solved by the Invention] However, when a charge control agent is contained in a toner resin, it is difficult to uniformly disperse it in the toner resin, and uneven charging occurs between toner particles or on the surface of the toner particles. Easy to occur. Further, even when a charge control agent is attached to the surface of toner particles, uneven charging tends to occur in the toner used, and it is difficult to obtain a toner with a stable charge amount over time. For this reason, with conventional toner particles, it is not possible to obtain particles that rise quickly and have uniform charging properties, which poses a problem in obtaining high-quality electrophotographic images.

An object of the present invention is to solve the above-mentioned problems and provide a toner that rises quickly, has good stability over time, and has high chargeability.

[Means for Solving the Problems] That is, the toner of the present invention is an electrophotographic toner characterized in that surface treatment agent particles are immobilized on the surface of the toner particles.

[Detailed Description of the Invention] (1) Constituent Components (1) The types of thermoplastic polymers constituting the matrix used in the electrophotographic toner of the present invention include ethylene, propylene, and butene-1. , pentene-1,4-methylpentene-1, hexene-11, etc. alone or copolymers with each other of α-olefins (including ethylene), as well as the majority by weight of these α-olefins and other unsaturations. Block, random or craft copolymers with compounds, or halogenated, sulfonated,
Olefin polymers such as modified polymers treated with oxidation etc., acrylonitrile/styrene copolymer (ASI'H resin), polycarbonate, thermoplastic polyester, polyamide, polystyrene, styrene/butadiene/styrene block copolymer , polyacnolonitrile, methyl methacrylate resin, and rubber.

In the above olefin polymer, other unsaturated compounds that can be copolymerized with α-olefin include vinyl esters such as vinyl acetate, vinyl silanes such as vinyltrimethoxysilane and vinyltriacetoxysilane, and the above-mentioned polymers. Examples include ethylenically unsaturated #mers other than a-olefins.

- Preferred matrix resins among these resins are styrene resins, acrylic resins, and polyester resins.

Examples of the styrenic resin used in the present invention include polystyrene, styrene and copolymerized esters, such as acrylic esters such as methyl acrylate, methacrylic esters such as methyl methacrylate and n-butyl methacrylate, and fumaric acid. A copolymer of fumaric acid diester such as dibutyl and dioctyl fumarate in an amount not exceeding the majority is used. Among them, the glass transition temperature is 30 to 105℃, and the number average molecular weight is 1000 to 15000.
0, especially those of 2,000 to 100,000 are effective.

These matrix resins have a 20 to 99
It is preferable to use overlapping %, more preferably 30 to 9
5% mold.

Examples of the blue agent used in the electrophotographic toner of the present invention include carbon black, basic dyes such as rhodamine B, acid dyes, fluorescent dyes, azo dyes, anthraquinone dyes, azine dyes, nigrosine dyes, These include metal complex compound dyes, red iron oxide, titanium oxide, cadmium yellow, cadmium red, basic dye lake, and phthalocyanine pigments. The amount of these colorants added is generally in the range of 0.05 to 15% by weight, more preferably about 0.1 to 12% by weight, based on the toner.

Further, when substantially the entire amount of the colorant is dispersed and filled in the domain resin, the colorant used has electrical properties that have greater adhesion to the domain resin than to the matrix resin.

In the electrophotographic toner of the present invention, the colorant can be dispersed and retained in the dispersion layer resin (domain resin), and this domain resin can be dispersed in the matrix resin. Using a domain resin in which this colorant is dispersed and held,
This prevents the coloring agent from being exposed to the toner surface, and has the effect of making the toner surface uniform in chargeability.

In particular, in the electrophotographic toner of the present invention, it is preferable that the domain resin is uniformly dispersed in the matrix resin, since there is no bleeding or color blurring.

As a domain resin that disperses and holds colorants.

Resins similar to the matrix resins described above can be used.

Generally, the matrix resin and the domain resin constituting the dispersed phase are selected to be of different types, but they do not necessarily have to be different types of thermoplastic polymers. In other words, even if the polymers are of the same type, their properties such as degree of polymerization, molecular weight, m name, 10/8 character, etc. can change due to differences in their manufacturing conditions or by treating one or both polymers. Let me,
It is possible to form the composition of the present invention if they are homogeneously immiscible with each other.

As a method for uniformly dispersing a domain resin containing a colorant in a matrix resin, a component constituting the domain resin (or matrix resin) is added by polymerization to a resin containing monomers constituting the Madnox resin (or domain resin). There is a method in which a modified polymer obtained by graft polymerization of a vinyl monomer that is
(See Japanese Patent Application No. 62-257967).

In addition to the above-mentioned essential ingredients, auxiliary materials such as low molecular weight olefin polymers, fatty acids and fatty acid metal salts can be used for the purpose of improving mold release properties etc. As the surface treatment agent used in the electrophotographic toner of the present invention, substances used in the surface treatment of ordinary toners can be appropriately selected and used. Specifically, inorganic substances include oxides such as silicon oxide, titanium oxide, and aluminum oxide, carbides such as silicon carbide, titanium carbide, and boron carbide, and nitrides such as boron nitride and silicon nitride. , azo dyes and pigments, and resins such as polymethyl methacrylate, polyvinylidene fluoride, and silicone resins.

These surface treatment agents are attached to the surface of toner particles in the form of fine powder and are driven into the surface of the toner particles by mechanical impact, so they account for 0.001-10% of the particle size of the toner.
, preferably 0.005 to 5% fine powder is used.

The amount of surface treatment agent used in the electrophotographic toner of the present invention is generally in the range of 0.01 to 10% by weight, more preferably in the range of 0.05 to 3.0% by weight, based on the toner. be.

(2) Production of toner particles The toner particles are prepared by blending the matrix resin, domain resin, coloring agent, etc., kneading using a kneader roll, press, etc., and then using a hammer mill or shelving mill.
Alternatively, by finely pulverizing and classifying as a solution with a spray dryer etc., the target particle size is 2-2hm,
Preferably, fine powder of 4 to 12 um can be produced.

(3) Immobilization The toner of the present invention can be obtained by attaching the surface treatment agent to the surface of the toner particles produced by the method described in V, and applying mechanical impact to the surface treatment agent to immobilize the surface treatment agent. It is formed.

Various methods may be employed for specific immobilization work, and for example, it may be performed using an apparatus such as the hybridization system manufactured by Shinara Kikai Seisakusho. In this hybridization system, toner particles and a surface treatment agent are mainly mixed using a V-type stirrer or the like, the surface treatment agent is electrostatically attached to the toner particles, and then heat and a! By simultaneously applying a mechanical strain force, the surface treatment agent is immobilized on the surface of the toner particles.

(4) Toner for electrophotography The toner for electrophotography of the present invention thus obtained is:
It has a fast charging start-up and stable charging properties over time.

The diameter of the toner particles is generally preferably 2 to 25 μm, more preferably 4 to 20 μm, particularly 4 to 12 μm.

[Example] In the example shown below, the electrophotographic toner of the present invention will be specifically explained using a toner using a domain resin, but the same applies to a toner that does not use a domain resin as shown in FIG. However, the electrophotographic toner of the present invention is not limited to the following examples.

Figure 1 shows that a surface treatment agent 2 is applied to the surface of toner particles 1, which are a mixture of matrix resin 3 and carbon black 4 as a coloring agent.
FIG. 2 is a cross-sectional view of an electrophotographic toner particle according to an embodiment of the present invention in which a surface treatment agent 2 is immobilized on the surface of a toner particle l using a domain resin 5 in which carbon black 4 is dispersed. 1 is a cross-sectional view of electrophotographic toner particles 1 according to an example of the present invention.

FIG. 3 is a cross-sectional view of toner particles I to which the surface treatment agent 2 in FIG. 2 is attached without being fixed.

The domain resin, matrix resin, and dispersion aid used in the Examples and Comparative Examples are as follows.

Gonogo” 1-Hib A Styrene lobe tyl acrylate-copolymer.

N-butyl acrylate content: 15% by weight.

Molecular weight: 64.000 Softening point: 140°C Blow-off charge measuring device Charge amount: -1hc/g Matrix resin B Styrene dimethyl acrylate-copolymer molecular weight:
13.000 Softening point: 130℃ Blow-off charge measuring device Charge amount: +45uc/g min liter
lv Tanukidan Modified styrene/acrylic acid ester copolymer prepared according to the following reference example.

Molecular weight: 90.000 Blow-off charge measuring device Charge amount: + lhc/g Reference example Production of modified styrene-acrylic acid ester copolymer In an autoclave with a capacity of 10ffi, 4 kg of water, 80 g of tricalcium phosphate, and dodecylbenzenesulfonic acid Add 0.12 g of soda to make an aqueous medium, and then add [
A solution obtained by dissolving 8 g of Nybar BJ in a mixed solution of 640 g of styrene and 160 g of lobetyl methacrylate was added and stirred. 1200 g of the matrix resin (styrene dimethyl acrylate copolymer) particles were added to this,
After replacing the inside of the autoclave with nitrogen, the temperature inside the system was set to 60℃.
The temperature was maintained for 3 hours to impregnate the styrene containing the polymerization initiator into the matrix resin particles.

Next, 11.4 g of Perbutyl PVJ was added to this suspension system, and the temperature inside the system was raised to 65° C. and maintained for 2 hours to initiate polymerization of the particle surface into a styrene polymer.

Thereafter, the system temperature was raised to 90° C. and maintained for 3 hours to complete polymerization.

After cooling, the contents were taken out and washed with acid and water to obtain 2 kg of modified resin particles. The content of vinyl monomers other than styrene in this product was 8% by weight.

Comparative Example I The following substances were melt-kneaded in a twin-screw extruder. 3 Domain resin A 20 parts by weight Carbon black #52 (manufactured by Mitsubishi Kasei ■) 5 parts by weight Zinc stearate 2 parts by weight Next, the following substances were mixed in a twin-screw extruder. The mixture was melt-kneaded using a kneading extruder.

20 parts by weight of the above mixture Matrix resin 8 70 parts by weight Dispersing aid
10 parts by weight of the obtained crosstalk material was pulverized using a jet mill to obtain toner A having an average particle size of 7.5 am.
I got it.

The amount of triboelectric charge of this material was measured over time by the blow-off method, and the results are shown in FIG. The angle of repose was 48 degrees.

Example 1 100 parts by weight of toner A obtained in Comparative Example 1 was mixed with 0.3 parts by weight of Aerosil R812 (Japan Aerosil Co., Ltd.), and heated at a temperature of 40°C using a hybridization system manufactured by Nara Kai Seisakusho. Aerosil was immobilized on the surface of eight toner particles under the conditions of 4800 rpm and 30 seconds to obtain toner B.

As shown in FIG. 4, the amount of triboelectric charge of this toner B was measured over time using a blow-off method, and as shown in FIG. 4, the charge build-up was fast and the amount of charge was extremely stable over time. The angle of repose was 44 degrees.

Comparative Example 2 0.3 parts by weight of Aerosil R812 was added to 100 parts by weight of Toner A produced in Comparative Example 1, and the mixture was mixed for 5 minutes using a homogenizer to produce Toner C, in which Aerosil was simply adhered to the surface of Toner A. Obtained.

When the amount of triboelectric charge of this toner C was measured over time using a blow-off method, it was found that there was a large change over time as shown in FIG.

[Effect of the Invention 1] The electrophotographic toner of the present invention has fine particles of a surface treatment agent fixed on the toner surface, and therefore exhibits uniform and good charging characteristics between toner particles and on the surface of individual toner particles. In addition, regardless of the fluidity that is the unique effect of the surface treatment agent,
It exhibits stable charging characteristics over time and has the effect of providing good electrophotographic images over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of toner particles for electrophotography of the present invention, illustrating a state in which a surface treatment agent is immobilized on the surface of toner particles containing carbon black as a colorant, and FIG. 1 is a cross-sectional view of electrophotographic toner particles according to an embodiment of the present invention, in which a surface treatment agent is immobilized on the surface of the toner particles. FIG. 3 is a cross-sectional view of toner particles in which the surface treatment agent in FIG. 2 is simply attached without being fixed. FIG. 4 shows the change over time in the amount of triboelectric charge of toner obtained by the blow-off method. ■...-Toner particles, 2...-Surface treatment agent, 3--Matrix resin, 4...-Carbon black, 5-...
domain resin.

Claims (2)

[Claims] (1) An electrophotographic toner characterized in that surface treatment agent particles are immobilized on the surface of the toner particles. (2) The electrophotographic toner according to claim 1, wherein a domain resin component filled with a colorant is dispersed in a matrix resin component.