JPH02238461A - Manufacture of toner - Google Patents

Abstract

PURPOSE:To enhance development performance and fixability by melting and kneading each of 2 kinds of specified toner components, then, extruding them from double nozzles composed of an inner cylinder and an outer cylinder having the same central axis so as to extrude one component into the inside and the other component into the outside to form a monofilament same in diameter as the toner, and cutting it. CONSTITUTION:Each of the toner component A containing at least a binder resin and the toner component B containing the binder resin and at least a low molecular weight polyalkylene and/or a wax is melted and kneaded in heat kneaders 2, 4, respectively, and extruded from the double nozzles 5 composed of the inner cylinder and the outer cylinder having the same central axis and having fine pores so as to extrude the component A into the inside and the component B into the outside to form the monofilament 6 same in diameter as the toner, and it is cut by the length corresponding to the toner diameter, thus permitting the obtained toner to be superior in fixability and development performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing toner used in electrostatic photography. [Prior Art] Conventionally, toner for electrostatic photography is produced by adding a coloring agent, a charge control agent, a fluidity improver, a mold release agent, etc. to a thermoplastic resin, and then kneading the mixture.
The so-called pulverization method, which involves pulverizing and classifying materials, is known. Although this method of manufacturing can produce fairly good toners, it does have certain limitations, namely the range of material selection for the toner. For example, the resin colorant dispersion must be sufficiently brittle to be pulverized in economically viable manufacturing equipment.
This requirement makes the resin colorant dispersion brittle, so when it is actually pulverized at high speed, particles with a wide range of particle sizes are likely to be formed, and in particular, there is a problem that a relatively large proportion of fine particles are included. arise.

Furthermore, such highly opaque materials are often further pulverized or powdered when used for development in copying machines and the like. In addition, with this method, it is difficult to completely and uniformly disperse solid particles such as magnetic powder or colorant into the resin, and depending on the degree of dispersion, this may increase fog and reduce image density. Therefore, we must pay attention to dispersion. Furthermore, since a conductor such as a magnetic material is exposed on the fractured surface, it may be difficult to manufacture an insulating toner. A toner manufacturing method that does not involve pulverization has been proposed in Japanese Patent Laid-Open No. 17735/1983. In these methods, monomers, polymerization initiators, colorants, magnetic materials, and other components are dispersed in water to directly obtain toner. However, a large amount of dispersant such as a water-soluble polymer substance or a poorly soluble inorganic substance is required. (humidity) affects the electrical conductivity of toner,
This significantly destabilizes the triboelectric properties of toner.

In addition, in the suspension polymerization method and emulsion polymerization method, magnetic substances and colorants exist unevenly on the particle surface, which results in a decrease in toner resistance and unstable W charging characteristics. , a clear copy image cannot be obtained. In addition, when the fine particles of the magnetic substance or colorant existing on the surface fall off, the range of particle size distribution of the toner is widened and the developability of the toner is deteriorated. In order to resolve this contradiction, toners have been proposed in which the developability and fixing properties are separated into a shell and a core to form a capsule. However, in reality, it is extremely difficult to make ultrafine capsules like toner, and it is not easy to actually obtain sufficient properties, and the manufacturing cost is also extremely high. Furthermore, as mentioned above, the conventional toner manufacturing method is as follows:
A thermoplastic resin and a coloring agent such as a dye or pigment are mixed and melted at high temperature, and the mixture is cooled to room temperature and ground into fine particles.

However, due to the manufacturing method, the toner produced by this method does not have a constant shape and particle size, and it is essentially difficult to obtain uniformity among the toners and uniformity within the toner. The resulting insufficiency in the practical performance of toner was manifested in various ways. In addition, producing toner using this manufacturing method requires a large amount of money, and in particular, the process of obtaining fine particles requires an extremely large amount of energy, which increases both equipment costs and running costs. Ta. Furthermore, such a manufacturing method greatly limits the materials to be used.

Furthermore, in order to obtain fine powder toner, the pulverization characteristics of the material are a major problem in terms of productivity. In other words, in order to be made into a toner, the binder must first be brittle, and this does not necessarily match the characteristics of the binder required from the performance of the toner. It could not be used in the manufacturing method.

In order to solve these problems, a method has been proposed in which toner particles are obtained by simultaneously forming particles and polymerizing them using a method such as so-called emulsion polymerization.

However, when producing toner using this method, it is difficult to completely remove the emulsifier and dispersant used to stabilize the dispersion, and it is extremely difficult to obtain toner with sufficient performance. there were.

On the other hand, in terms of properties used in toner used in electrophotography, it is important to have electromagnetic properties that are excellent in development, as well as to prevent adhesion to the fixing roller, so-called offset, as well as fixing properties. By making the resin that forms the toner elastic by crosslinking and adjusting the molecular weight distribution, and by mixing and containing low molecular weight polyalkylene and wax components in the resin, the resin is shear-melted on the heat fixing roller, and the gap between the roller and the toner is A method is used to prevent offset by forming an oil film on the surface.

However, low molecular weight polyalkylene and wax components are difficult to be compatible with binder resins, and if you try to include the necessary amount in the toner to produce the effect, the amount added will be large, and other colorants, charge control agents, etc. Prevents separation of magnetic materials, etc. This causes a decrease in image density, image stains such as fog, and, in the case of color toners, color turbidity due to color mixing. Furthermore, when color toners are copied onto an OHP, there is a problem in that the addition of excessive low molecular weight polyalkylene or wax reduces light transmittance and impairs sharpness. [Problems to be Solved by the Invention] An object of the present invention is to provide a toner manufacturing method that solves the above-mentioned problems. An object of the present invention is to provide a method for producing a toner having excellent fixing properties and good developing performance.

An object of the present invention is to provide a method for producing a toner that exhibits stable performance even after repeated use and that does not aggregate or contaminate the carrier, metal sleeve, or photoreceptor surface. An object of the present invention is to provide a method for producing a pressure fixing toner that does not cause offset to a pressure roller and does not cause contamination of a carrier, a developing sleeve, and a photoreceptor. A further object of the present invention is to provide a method for producing a toner that is stable and does not change even after multiple uses, is stable even when stored for a long period of time, and does not change in a storage container. That's true. An object of the present invention is to provide a method for producing toner having a uniform shape and homogeneous composition.

A further object of the present invention is to provide a method for producing toner at a lower cost. Another object of the present invention is to provide a method for producing a color toner that has excellent chroma, has good light transmittance when used in OHP, and is capable of producing clear images. [Means and effects for solving the problems] The present invention provides a toner component (A) containing at least a binder resin, and a toner component (B) containing a binder resin and at least a low molecular weight polyalkylene and/or wax. ) and then extruded through a double nozzle consisting of an inner cylinder and an outer cylinder with the same central axis and having fine holes so that the toner component (8) is on the inside and the toner component (B) is on the outside. , is a toner manufacturing method characterized in that the monofilament is made into a monofilament having a diameter equivalent to the toner, and then cut into a length equivalent to the toner.

According to the manufacturing method of the present invention, it is possible to contain a low molecular weight polyalkylene or wax in the toner surface layer, without inhibiting the dispersion of the colorant etc. contained inside the toner.
Moreover, it has been discovered that it can be made into a toner with extremely excellent transparency. Furthermore, the manufacturing method of the present invention includes only a pre-mixing step of toner materials, a step of melt-kneading, a step of manufacturing a monofilament using a micro-hole nozzle, and a cutting step. , toner performance can be added. Furthermore, there are no restrictions on the toner materials used, as in the past, and it is possible to select a variety of materials required for the original toner performance. Furthermore, by shortening the manufacturing process, cheaper toner can be manufactured. Further, by the stretching process or the like, it is possible to form a new capsule toner structure, which was not possible with conventional manufacturing methods, and it is possible to produce a capsule toner with superior performance and a toner with a new function.

As described above, the method for producing capsule toner of the present invention includes:
The goal is to solve the problems of conventional products and manufacture capsule toners that not only have superior performance but also have new functions. The present invention will be explained in detail below.

An outline of the manufacturing process of the present invention is shown in Figures 1 (1) and (2).
Shown below. In FIG. 1 (1), raw materials constituting the core material of the capsule toner are mixed in a premixer 1, then melted and kneaded in a heating kneader 2, and then supplied to a nozzle section 5 of a kneading extruder 4. ．． At the same time, the raw materials constituting the outer shell of the capsule toner are mixed in a premixer 3, and then melted and kneaded in a heating kneading extruder 4 to form micropores consisting of an inner cylinder and an outer cylinder with the same central axis at the tip. From the double nozzle 5, a monofilament 6 having a multilayer structure is extruded, with the center consisting of component (8) constituting the core material of the capsule toner, and the component (B) constituting the outer shell of the capsule toner surrounding the component (8). Here, from the viewpoint of load pressure and production efficiency, it is preferable to have a large number of fine holes, and the hole diameter of the nozzle is adjusted according to the desired toner particle size and stretching ratio.

Next, the monofilament 6 extruded from the nozzle 5
The cutting device 7 makes the particles finer. As this method, it is also possible to mechanically cut the semi-molten monofilament 6 discharged from the fine holes in the nozzle using a high-speed rotary cutter.
It is also an effective method to cut by irradiating a laser beam as a fine spot.

At this time, due to the melt viscoelasticity of the polymer material, the cut surface is
It has a spherical shape.

Furthermore, by drawing the monofilament 6 with the drawing device 9 as shown in FIG. 1 (2), the nozzle diameter can be increased, further increasing productivity, and the monofilament diameter can be adjusted to a desired value by drawing. can. Furthermore, it has been discovered that stretching can cause stretch alignment in the binder resin, thereby producing toner particles with distinctive polarization characteristics. In addition, when containing charge control agents, colorants, magnetic substances, etc., these also tend to be oriented in the stretching direction,
It was found that the anisotropy of magnetic properties and polarization properties became more pronounced, and it became clear that the toner exhibited completely new toner performance that had never existed before. Here, the stretching temperature can be selected as appropriate within the temperature range from above the glass transition temperature to below the melting point of the binder resin. Generally, a higher stretching ratio is possible at a higher temperature, but if the temperature is too high, the molecules It begins to slide without being stretched. On the other hand, if the stretching temperature is too low, it will be difficult to stretch, microvoids will occur in the filament, and the stretching effect of the coloring agent will be insufficient, resulting in problems with uniformity. The stretching ratio is 1.5 to 50 times, preferably 2 to 20 times.

With magnetic toner, it is thought that the magnetic force is strengthened by stretching, but the spikes of toner are regular and cause disturbances in image quality.Also, the spikes of toner are short, causing protrusion from the latent image and scattering of the toner. It is possible to obtain extremely high-quality images. Furthermore, for this reason, it is possible to reduce the amount of magnetic material required, improving fixing properties,
It also has the advantage of improving image quality and making kneading easier since the ears are not made longer than necessary.

As described above, the manufacturing method of the present invention not only provides a manufacturing method with shorter steps and lower costs than the conventional method, but also provides a manufacturing method that is less expensive than the conventional method. The unique toner structure achieves excellent toner performance that has not been achieved previously.

The binder resin used as the core material and shell material of the toner used in the present invention can be selected from a wide range of known resins, including styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, etc. Substituted homopolymers: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene- Ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid Butyl copolymer, styrene-alpha-chloromethyl methacrylate copolymer, styrene-acrylic nitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer Polymers, styrenic copolymers such as styrene-butadiene copolymers, styrene-isobrene copolymers, styrene-acrylic nitrile-indene copolymers, styrene-maleic acid copolymers, and styrene-maleic ester copolymers. Coalescence; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyamide, polyacrylic acid resin, rosin, modified mouth resin, terben resin, Phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, carnauba wax, etc. can be used alone or in combination. In addition, it is recommended to use a crosslinked resin if necessary. At this time, it is effective for the stretching stability in the stretching process, the spheroidizing effect of the cut portion, and the offset resistance of the toner.

In addition, examples of the low molecular weight polyalkylene and wax to be included in the component (B) constituting the general material in the present invention for the purpose of improving mold releasability during hot roll fixing include low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight There are waxy substances such as molecular weight propylene-ethylene copolymer, low molecular weight ethylene-butene copolymer, etc., microcrystalline wax, carnauba wax, Sasol wax, paraffin wax, etc., and 100 parts by weight of the binder resin that makes up the outer shell. It is good to add 0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight. As the coloring agent used in the present invention, conventionally known dyes and pigments can be used, such as phthalocyanine blue, peacock blue, permanent dread, laked, rhodamine lake, banza yellow permanent yellow,
It can be widely used such as benzine yellow. The content thereof is preferably 0.5 to 20 parts by weight per 100 parts of the binder resin, preferably 12 parts by weight or less to roughly improve the permeability of the OHP film, and more preferably 0.5 to 20 parts by weight.
5 to 9 parts by weight is good. Examples of carriers that can be used in the present invention include magnetic powders such as iron powder, ferrite powder, and nickel powder, and those whose surfaces have been treated with resin or the like. Carrier lO to 1000 parts by weight (preferably 30 to 500 parts by weight) per 10 parts by weight of toner
parts by weight) is better to use. The carrier particle size is 4
~100 μm (preferably 10 to 60 μm) is preferred.

When the toner of the present invention is used as a magnetic toner, examples of the magnetic material include iron oxides such as magnetite, gamma iron monoxide, ferrite, and iron-rich ferrite; metals such as iron, cobalt, and nickel, or combinations of these metals. Aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium,
Mention may be made of alloys and mixtures thereof with metals such as manganese, selenium, titanium, tungsten, vanadium.

It is desirable that these ferromagnetic substances have an average particle size of about 0.1 to 1 μl, preferably about 0.1 to 0.5 μl, and the amount contained in the magnetic toner is 60 to 110 parts per 100 parts by weight of the resin component. parts by weight, preferably 65 to 100 parts by weight per 100 parts by weight of the resin component! It is i quantity part.

Furthermore, in order to improve the dispersibility and moisture resistance of the magnetic powder, hydrophobically treated magnetic powder can also be used. Hydrophobization treatment is carried out at 0.0 parts by weight per 100 parts by weight of magnetic powder.
Hydrophobic treatment is performed using a treatment agent such as a titanium coupling agent, a silane coupling agent, or an aluminum coupling agent in an amount of 1 to 5 parts by weight. Further, in the magnetic toner or non-magnetic toner according to the present invention, it is preferable that a charge control agent is added to the toner particles (internal addition) or mixed with the toner particles (external addition). The charge control agent makes it possible to optimally control the amount of charge depending on the developing system.Furthermore, in the production method of the present invention, orientation occurs due to stretching of the charge control agent, stabilizing polarization of charges within and between toners, and magnetic properties. With toner, the spikes of toner can be arranged in a regular and dense forest, and even with non-magnetic toner, it is possible to cover the sleeve, photoreceptor, and transfer paper with a thin layer of toner. , which is extremely effective in improving image quality. As a positive charge control agent, modified products such as nigrosine and fatty acid metal salts; tributylbenzylammonium-1
-Quaternary ammonium salts such as hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide: dibutyltinborate, dioctyltinborate, dicyclohexyltin Diorgano tin borates such as borates can be used alone or in combination of two or more. Among these, charged iIiIJ agents such as nigrosine and quaternary ammonium salts are particularly preferably used. In addition, the general formula ＼ R3 R. :H. CH3 R2, R3: a 1,000-nomer homopolymer represented by a substituted or unsubstituted alkyl group (preferably C I-C a ): or a polymerizable polymer such as styrene, acrylic ester, methacrylic ester as described above Copolymers with 1,000,000,000,000,000,000,000, and 1,000,000,000,000 can be used as positive charge control agents, in which case these charge control agents also act as (in whole or in part) a binder resin. Examples of effective negative charge control agents that can be used in the present invention include organometallic complexes and chelate compounds.
Examples include aluminum acetylacetonate, iron (! summer) acetynoleacetonate, chromium 3,5-ditertiarybutylsalicylate, etc. Acetylacetone metal complexes, salicylic acid metal complexes or salts are particularly preferred, and salicylic acid metal complexes are particularly preferred. Complexes or salicylic acid metal salts are preferred.

The above-mentioned charge control agent (one that does not act as a binding resin) is preferably used in the form of fine particles. In this case, the number average particle size of this charge control agent is specifically:
It is preferably 4 μm or less (more preferably 3 μm or less). When internally added to the toner, such a charge control agent is added in an amount of 0.1 to 20 parts by weight (or even 0.1 to 20 parts by weight) per 100 parts by weight of the binder resin.
．． 2 to 10 parts by weight) is preferably used.

Further, it is preferable to add fine silica powder to the magnetic toner and non-magnetic color toner of the present invention.

When the toner according to the present invention is combined with fine silica powder, wear is significantly reduced due to the presence of fine silica powder between the toner particles and the sleeve surface. As a result, the life of the magnetic toner and the sleeve can be extended, and stable charging properties can also be maintained, making it possible to obtain a developer having toner that is more excellent even for long-term use.
Other additives include, for example, lubricants such as zinc stearate, or abrasives such as cerium oxide, silicon carbide, or flow agents such as colloidal silica, aluminum oxide, anticaking agents, or e.g. carbon black, oxidized There are conductivity imparting agents such as tin. [Examples] The present invention will be specifically explained below with reference to Examples, but these are not intended to limit the present invention in any way. Note that all parts in the following formulations are parts by weight.

[Large] U1 process - Toner component (A) that forms the core material - Component (B) that forms the outer shell The manufacturing method will be explained using Figures 1 and 2. Pre-mix the above material (A) in a Henschel mixer l,
The mixture was kneaded at 120°C using a two-wheeled kneading extruder 2. At the same time, material (B) was introduced into the two-wheeled kneading extruder 4. 15
The mixture was kneaded at 0°C. The die has approximately 100 fine hole nozzles with a coaxial inner/outer dual structure as shown in Fig. The melt in (B) passes through the breaker plate 11 and is supplied to the outer shell. At this time, the weight ratio of each supply was set to 75:25. A monofilament with a multilayer structure consisting of a core made of material (A) and an outer shell made of material (B) was taken out and introduced into a drawing device. The inside of the stretching device was set at 85 to 90°C, and the stretching ratio was about 10 times.
A monofilament with a diameter of 10μ was used. Next, it was cut into a length of about 10 μm using a high-speed rotating ceramic cutting blade to obtain a black fine powder. The volume average diameter of this black fine powder is 11.0μ, the number average diameter is 9.8μ■,
It had a relatively uniform particle size distribution. 0.4 part of hydrophobic silica was mixed with 100 parts of the black fine powder using a Henschel mixer to prepare a magnetic capsule toner.

Using the magnetic capsule toner, electrophotographic copying machine NP3
Image output was evaluated under conditions that were more severe against offset by removing the oil supply device of the fuser of the 725 (manufactured by Canon). The toner coating on the toner carrier sleeve of the developing machine was very uniform, the image density was as high as 1.38, and a clear image was maintained even after repeated copying.

Even in a durability test of 10,000 sheets, no offset occurred. In addition, the cost of manufacturing toner is
It was about 35% of the manufacturing cost of conventional toner.

[Act] 11l - Toner component (A) serving as core material - Toner component (B) serving as outer shell Using the above materials, red fine powder was obtained in the same manner as in Example 1. At this time, the stretching temperature was 90 to 95°C, and the stretching ratio was 10 times. The volume average diameter of the obtained red fine powder was 12.0μ■. A two-component developer was prepared by mixing 9 parts of the color toner with 100 parts of a fluorine/acrylic resin-coated ferrite carrier (average particle size of about 65 μs).

The two-component developer was applied to a color toner developer of an electrophotographic copying machine NP6550 (manufactured by Canon), and image output was evaluated. The toner coating on the toner carrier sleeve of the developing machine is extremely uniform, the image density is as high as 1.38, and the fine line reproducibility and resolution are excellent, and even after repeated copying, clear images are maintained stably. It was maintained. Furthermore, when copied onto an OHP, the light transmittance was good and a red image could be projected. Furthermore, the cost for manufacturing the toner was approximately 45% of the cost for the conventional pulverization method.・Ingredients that form the outer shell (B
) The above materials were premixed, kneaded, discharged, stretched, and cut in the same manner as in Example 1. Stretching conditions are stretching temperature 80-85
℃, and the stretching ratio was about 15 times. The volume average diameter of the obtained black fine powder was 7.5μ, and the number average particle diameter was 6.5μ.
1 and had a relatively uniform particle size distribution. A magnetic toner was prepared by mixing 100 parts of the black fine powder with 0.8 parts of hydrophobic positively charged silica fine powder using a Henschel mixer. Using this toner, image reproduction evaluation was performed in the same manner as in Example 1, and the image density was as high as 1.44.
There was no trailing, and even fine lines were reproduced extremely faithfully, with good resolution. In particular, when observing the developing sleeve, compared to normal toner of the same particle size, the sleeve
The coating was uniform, the spikes were as short as 70 μm, and the spikes of each toner particle stood alone without overlapping. In addition, there is little image fogging, and it is presumed that the magnetic binding force to the sleeve is greater compared to the same amount of magnetic material. too
No offset occurred even in durable copying of 00 sheets. Furthermore, the cost involved in manufacturing the toner was 45% of the manufacturing cost of conventional toner.

[Effects of the Invention] According to the present invention, an inexpensive toner can be manufactured by shortening the manufacturing process, and there are no conventional restrictions on the toner materials used, and a toner with better performance can be manufactured. be able to.

[Brief explanation of drawings]

Figures 1 (1) and (2) schematically show the manufacturing apparatus of the present invention, and Figure 2 schematically shows the shape of the nozzle section of the extruder, which has a dual coaxial inner-cylinder structure. 1.3...Pre-mixer
2.4... Melt kneader 5... Nozzle part
6... Monofilament 7... Cutting/refining device 8... Product 9... Stretching device 11... Breaker plate (equipped in kneading machine 4 in Fig. 1) 12... Nozzle microhole l3 ... Extruder die section main body 14 ... Nozzle die section 15 ... Breaker plate (equipped in the kneading machine 2 in Fig. 1)

Claims (2)

[Claims] (1) Toner component (A) containing at least a binder resin
After melt-kneading the binder resin and toner component (B) containing at least low molecular weight polyalkylene and/or wax, a double nozzle consisting of an inner cylinder and an outer cylinder having the same central axis and having fine holes is formed. Toner ingredients (
A method for producing a toner, which comprises extruding the monofilament so that A) is on the inside and the toner component (B) is on the outside to form a monofilament with a diameter equivalent to the toner, and then cutting the monofilament into a length equivalent to the toner. (2) The manufacturing method according to claim (1), characterized in that after extrusion through the double nozzle, the monofilament is stretched to form a monofilament having a diameter equivalent to that of the toner.