JPS63138358A - Production of toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a toner for developing an electrostatic charge image which decreases toner splashing in a developing stage and fogs less by sticking electrostatic charge control agent particles to the surface of the base particles of the toner and exerting impact force to the toner under special conditions. CONSTITUTION:The base particles of the toner consisting of a binder resin and dye pigment and the electrostatic charge control agent particles are mixed to stick the charge control agent particles on the surface of the base particles of the toner to form the composite particles; thereafter, the impact force is exerted to such composite particles in 50-300m/sec gaseous flow to fix the charge control agent particles onto the surfaces of the base particles of the toner. The developer which permits the development and transfer faithful to a latent image, i.e., the toner which obviates the fogging and toner splashing, yields a high image density and has the good reproducibility of halftones is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a toner for developing electrostatic images with less toner scattering in the developing step and less fog.

(Prior art 9) In electrophotography, an electrostatic latent image is generally formed on a photoreceptor using a photoconductive substance by various means, and then the latent image is developed using toner and transferred to paper. After that, it is generally fixed by heat or pressure to obtain a copy.

The step of developing an electrostatic latent image is a step in which charged toner particles are attached to the surface of an electrostatic image support by electrostatic force to visualize the electrostatic image.

In order to impart chargeability to the toner, it is also possible to utilize the triboelectricity of the binder resin, which is a component of the toner, but the amount of charge is small. Therefore, in order to impart desired triboelectric charging properties to the toner, a charge control agent such as a dye or a pigment is added to the toner.

These charge control agents are usually added to and dispersed in a thermoplastic resin which is a binder resin of a toner. As a way to disperse
A method of hot melt dispersion using a roll, kneader or extruder, a method of dispersing or dissolving a charge control agent in a monomer during resin polymerization, a method of dispersing it in a resin, a method of dissolving the resin in a solvent and dispersing it in the solution. There is a method in which a charge control agent is dispersed or dissolved in a toner, and then a toner is prepared and dispersed by spray drying or the like.

Electrification of toner is generated in a developing device due to friction between toner and carrier, toner and developing sleeve, toner and blade, or toner and toner.

In this case, the charge control agent that contributes to charging is only effective if it exists near the toner surface, and the charge control agent dispersed inside the toner does not contribute to charging. Further, the dispersion state of the charge control agent present near the toner surface and the amount of charge control agent present near the toner surface determine the amount of charge of the toner. Toners produced by conventional methods have a major problem in that the dispersion state and amount of the charge control agent vary from toner particle to toner particle, and the amount of triboelectric charge varies between toner particles.

When the amount of triboelectric charge differs between toner particles, problems such as development fog and toner scattering are likely to occur, and this phenomenon becomes particularly noticeable when a large number of copies are made.

Toners produced by conventional techniques have many problems caused by the dispersion of charge control agents, and there is a strong demand in this technical field to solve these problems.

(Problems to be Solved by the Invention) An object of the present invention is to provide a toner manufacturing method that solves the above problems. That is, an object of the present invention is to use a developer that can faithfully develop and transfer a latent image, that is, without fogging or toner scattering, and that can provide high image density.
An object of the present invention is to provide a toner for developing electrostatic images with good reproducibility of seven tones.

(Means for Solving the Problems) This object of the present invention is to mix toner base particles consisting of a binder resin and dye/pigment with charge control agent particles so that the charge control agent particles are attached to the surface of the toner base particles. Production of a toner for developing an electrostatic image, which is characterized in that, after forming composite particles, impact force is applied to the composite particles in an air flow of 50 to 300 rn/IIec to fix charge control agent particles to the surface of toner base particles. This is accomplished by a method.

Here, "adhesion" refers to the state of bonding between toner base particles and charge control agent particles due to electrostatic attraction, and "adhesion" refers to the physical state in which charge control agent particles are driven onto the surface of toner base particles by impact force. indicates a specific combination.

As the binder resin used for the toner base particles, yf! '
) Homopolymers of styrene and its substituted products such as styrene, polyp-chlorostyrene, and hollyhinyltoluene; styrene-p-chlorostyrene copolymer, nutyrene-propylene copolymer Toluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, nutyrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, Styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylate copolymer, stele/-α-chloromethyl methacrylate copolymer, nuterene-acrylonitrile copolymer, nutele 7.f-vinyl methyl ether copolymer, 7.f-rene-vinyl ethyl ether copolymer, nutyrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-yne f L/y copolymer, styrene- Styrenic copolymers such as acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer: polymethyl methacrylate, I-butyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, Polypropylene, polyester, polyurethane, I-lyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin Rough-in wax and the like can be used alone or in combination.

Binder resins suitable for providing toners particularly suitable for pressure fixing include polyolefins (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, polyethylene oxide,
7-ethylene (7), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio: 5~
30:95-70), olefin copolymer (ethylene-
Acrylic acid copolymer, ethylene-acrylic ester copolymer, ethylene-methacrylic acid copolymer, ethylene-
methacrylic acid ester copolymer, ethylene vinyl acetate copolymer, ionomer resin), polyvinylpyrrolidone,
Examples include methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, and phenol-modified terpene resin.

As dyes and pigments, carden black, lamp pla, ri,
Iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, 7 thalocyanine green, Handy Yellow G1, rhodamine 6G lake, calco oil blue, chrome yellow, kitri IJ ton, benzidine yellow, rose bengal, triallylmethane dye Conventionally known dyes and pigments such as monoazo, disazo, and disazo dyes and pigments may be used alone or in combination. The toner of the present invention can further contain a magnetic material and be used as a magnetic toner.

Magnetic materials include iron oxides such as magnetite and ferrite; metals such as iron, cobalt, dichloride, and kel; or these metals and aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, Examples include alloys with metals such as cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

The toner base particles in the present invention are prepared by thoroughly mixing a binder resin, dyes and pigments, and if necessary, magnetic materials, additives, etc. using a mixer such as a &-lumil, and then heat-kneading the mixture using a heating roll, a niegoo, an extruder, etc. It can be obtained by melt-kneading using a machine, cooling and solidifying, and then pulverizing and classifying. Alternatively, the material can be obtained by dispersing the material in a binder resin solution and then spray-drying it, or by mixing the specified material with the monomers that should constitute the binder resin to form an emulsified suspension and then polymerizing it. The mold can also be formed by a polymerization method to obtain toner base particles.

The shape of the toner base particles is not particularly limited and may be any shape such as spherical, elliptical, irregular, etc., but is preferably spherical in order for the charge control agent particles to uniformly adhere to the surface of the toner base particles. The particle size of the toner base particles is 1 to 50 μm, preferably 5 to 30 μm.

As the charge control agent in the present invention, charge control agents currently known in the field of electrophotography are used.

Nigrosine, which controls toner to be positively charged,
Organic dyes such as azine dyes containing alkyl groups having 2 to 16 carbon atoms, basic dyes, basic dye lake pigments, C, 1, Bent Black, Handy Yellow G, quaternary ammonium salts, dibutyltin oxide, etc. Tin compounds, metal salts of higher fatty acids, etc., as well as metal complexes of monoazo dyes, metal complexes of salicylic acid, naphthoic acid, dicardic acid such as Co, Cr, F@, sulfones, etc. to control the negative chargeability of the toner. Copper phthalocyanine pigments, nitro groups, styrene oligomers with Norogon introduced therein, chlorinated paraffins, and the like.

Since the charge control agent particles need to be attached and fixed to the surface of the toner base particles, their particle size needs to be smaller than the particle size of the toner base particles, and is preferably 0.05 to 5 NL.

The mixing ratio (weight ratio) of the toner base particles and the charge control agent may be sufficient as long as the amount is sufficient to obtain the charging cap necessary for developing the electrostatic latent image, and the mixing ratio (weight ratio) of the toner base particles to 100 parts by weight of the toner base particles may be sufficient. 0.01
~5! Parts by weight are preferred.

In the present invention, the steps of manufacturing the target toner are as follows:
It consists of two processes. The first step is a step of mixing a mixture of toner base particles and charge control agent particles under electrical insulation and electrostatically adhering the charge control agent particles to the toner base particles. In other words, since toner base particles and charge control agent particles are made of different materials, ditoner base particles and charge control agent particles with different charge types do not repel each other and aggregate, while toner base particles The charge control agent particles and the charge control agent particles electrostatically attract each other and the charge control agent particles electrostatically adhere to the surface of the toner base particles.

Examples of mixing means in this step include general stirrers and mixers such as a V-blender, a mortar mixer such as a double cone tumbler, a paddle stirrer, a turbine stirrer, and a Henschel mixer.

In the first step, the bonding force between the toner base particles and the charge control particles is weak and detachment may occur, so the second step is necessary. In the second step, the composite particles generated in the first step are dispersed in a high-speed airflow, and the composite particles are collided with each other or with a collision plate, a high-speed rotary blade, or a high-speed rotary bottle to form toner base particles and charge control agent particles. This is a step in which charge control agent particles are fixed to the surface of toner base particles by applying an impact force between the toner particles. The speed of the air flow in this step varies depending on the mechanism of the toner base particles and charge control agent particles and the desired degree of adhesion, but the speed is 50 to 50.
300rn//s@c, preferably 80-200 rQ
/see. If it is less than 50 Iv'sec, sufficient impact will not be obtained and the adhesion will not be sufficient, and 300 Vs e
If it exceeds e, the composite particles will collide and then be crushed, making it impossible to obtain the desired composite particles. Although the mixing time varies depending on the mixer used, 1 to 10 minutes is usually sufficient.

The mixing means used in this process generates high-velocity airflow;
Any mixer or crusher may be used as long as it has a structure in which composite particles collide with each other or with a collision plate, high-speed rotary blade, or high-speed rotary pin.

Tomil (e.g., Nippon Ichi Niemachiku's processing type mill, Alpine's Rakije, Tomil, etc.), various impact crushers (e.g., Alpine's pin mill, Nara Kikai Seisaku Co., Ltd.'s Cosmo My Day, Hypurity Day, Terx mill, etc.) etc.).

In the second step, a toner having a structure in which charge control agent particles are fixed to the surface of toner base particles is manufactured.

A toner having such a structure can provide good image quality with less development capri and toner scattering.

(Effects of the Invention) Thus, according to the present invention, compared to the prior art, the developer is capable of developing and transferring a latent image faithfully, that is, there is no capri or toner scattering, it provides high image density, and it is capable of producing halftone images. People can obtain toner with good reproducibility.

(Examples) The present invention will be described in more detail with reference to Examples below. Note that parts and parts in Examples and Comparative Examples are based on weight unless otherwise specified.

Example 1 50 parts of polyethylene wax, 50 parts of paraffin wax
After 2225 parts of the mixture and the cargo knob were mixed and dispersed in a roll mill heated to 130° C., the mixture was sprayed in a molten state with a spray dryer to obtain spherical toner base particles having a volume average particle diameter of 12 μm.

To 100 parts of the toner base particles, 1.3 parts of a charge control agent Pintron 5-34 (Orient Chemical) was added to a Henschel mixer FMIO type, and stirred at 1750 rpm for 3 minutes.

Next, the airflow velocity was adjusted to 100 m/s@cK using Hypurity Day (Nara Kikai Seisakusho), and the above mixture was introduced into the airflow. After a mixing time of 3 minutes, the mixture was discharged to obtain a toner.

Five parts of this toner was mixed with 10 parts of iron oxide carrier to prepare a two-component developer. This developer was applied to a 1) Pe copying machine with a selenium photoreceptor having a pressure fixing mechanism to perform continuous copying, and the capri on the copy paper and the toner scattering inside the copying machine were observed as described below.

As a result, as shown in Table 1, good results were obtained for both capri and toner scattering.

Capri: Copy paper was visually observed and the degree of damage was determined.

○ No capri.

There are Δ and scabs.

X Capri is severely unusable.

Toner scattering property: When a predetermined number of copies was reached, the inside of the copying machine was observed, and the state of toner scattering was visually determined.

○ No scattering.

Δ Slight scattering.

× Severe scattering.

Comparative Example 1 50 parts of polyethylene wax, 22747722250
Part, car? After cross-dispersing 5 parts of carbon black and 1.3 parts of a charge control agent (Gentron 5-34) in a roll mill heated to 130°C, they were sprayed in a molten state with a spray dryer to form spherical particles with a volume average particle size of 12 μm. Got toner.

Five parts of this toner were mixed with 100 parts of iron oxide carrier to prepare a two-component developer. This developer was applied to a pPe copying machine with a selenium photoreceptor having a pressure fixing mechanism, and continuous copying was performed, and capri on copy paper and toner scattering inside the copying machine were observed. As a result, as shown in Table 1, blurring and toner scattering occurred during continuous copying.

Example 2 70 parts of styrene, 20 parts of n-butyl methacrylate,
A monomer composition was prepared by mixing and dispersing 10 parts of butyl acrylate, 5 parts of Cargen Black, and 2 parts of lauroyl peroxide.

On the other hand, a seven-year-old Rubble Flask K with a capacity of 2. The above monomer composition was added to the polyvinyl alcohol aqueous solution of part O, and the temperature was raised to 65°C while stirring with a stirrer "TK Homo Mixer" (Tokushu Kika Kogyo) K at a rotation speed of 3.00 Orpm. and maintained at this temperature. After 30 minutes of temperature rise, polymerization was carried out for 10 hours while stirring at a rotational speed of 10 rpm using a conventional stirrer to complete the reaction. After completion of polymerization, the solid particles are separated and dried to a volume average particle size of 11.5 μm.
m toner base particles were obtained.

2.0 parts of a charge control agent Bondron E-82 (Orient Chemical) was added to 100 parts of the toner base particles in a Henschel mixer FMIO type, and the mixture was stirred and mixed at 1.75 Orpm for 3 minutes. Furthermore, the air flow rate was adjusted to 90 m7'fl@e using a jet mill manufactured by Japan Ichi Matikuku Co., Ltd., and the above mixture was introduced into the air flow.

The particles were discharged after a mixing time of 3 minutes to obtain a toner.

Five parts of this toner were mixed with 100 parts of iron oxide carrier to prepare a two-component developer. Using this developer, continuous copying was performed by applying it to a PPe copying machine having a selenium photoreceptor, and the capri on copy paper and toner scattering inside the copying machine were observed.

As shown in Table 1, good results were obtained in terms of toner scattering, capri, and toner scattering.

Comparative example 2 70 parts of styrene, n-butyl methacrylate 720 parts
10 parts of butyl acrylate, 5 parts of carden plastic, 2 parts of charge control agent (Gentron E-82) and 2 parts of lauroyl peroxide were mixed and dispersed to prepare a monomer composition, and the same procedure as in Example 2 was carried out. A toner having a volume average particle diameter of 12 μm was obtained.

Five parts of this toner was mixed with 100 parts of iron oxide carrier to prepare a two-component developer. This developer is applied to the selenium photoconductor ppc.
Continuous copying was performed using a copying machine, and the capri on copy paper and toner scattering inside the copying machine were observed. As shown in Table 1, capri and toner scattering were observed during continuous copying.

Clothes 1 Examples 3 to 4, Comparative Examples 3 to 4 The same experiment as in Example 1 was conducted except that the air flow rates shown in Table 2 were omitted. The results are shown in Table 2.

Table 2

Claims (1)

[Claims] After mixing toner base particles consisting of a binder resin and dye and pigment with charge control agent particles and adhering the charge control agent particles to the surface of the toner base particles to form composite particles, the composite particles are
A method for producing a toner for developing an electrostatic image, which comprises applying an impact force in an air flow of 00 m/sec to fix charge control agent particles to the surface of toner base particles.