JPH02146056A - Manufacture of toner - Google Patents

Abstract

PURPOSE:To obtain an inexpensive conductive toner superior in both of conductivity and fixability characteristics by forming a conductive layer made of a mixture of fine thermoplastic resin particles and a conductive material on the surfaces of particles made of at least a resin and a colorant by a mechanochemical reaction. CONSTITUTION:The conductive layer is obtained by mixing the fine thermoplastic resin particles and the conductive powder, and attaching this mixture to the surface of the base particles made of at least the resin and the colorant by the mechanochemical reaction. Since this reaction utilizes both thermal and mechanical energies, it coats the surfaces of the particles with the resin layer and also disperses the conductive material into the resin coating layer, thus permitting the inexpensive conductive toner superior in conductivity characteristics and fixability to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dry developing toner used in electrophotography and the like. Specifically, the present invention relates to a method for producing a conductive toner.

[Prior Art] Conventionally, conductive toner used in conductive magnetic component development methods using photosensitive paper has been prepared by adding conductive powder or, most commonly, by adding special There is a method of externally adding conductive powder to the toner surface, as disclosed in Japanese Patent Publication No. 63-33696 and Japanese Patent Application Laid-Open No. 49-5035.

External addition methods include stirring the powder using a mixer, dispersing the toner, binder, and conductive powder in a solvent, and spray-drying with a spray dryer to add the binder to the toner surface. There is a method of coating the toner with conductive powder, and a method of dispersing the toner and conductive powder in an aqueous solution, adhering the conductive powder to the toner surface, and then drying it.

[Problems and objects to be solved by the invention] However, in the above method, the adhesion of the conductive powder attached to the surface is weak, and the conductive powder is peeled off from the toner surface during toner transport and development, resulting in charge injection. is not carried out sufficiently,
The developing characteristics deteriorate, and the image quality deteriorates due to a decrease in image quality and background fog due to toner scattering. It also has the disadvantage that aggregation tends to occur. Furthermore, the peeled-off conductive powder contaminates the inside of the device, resulting in adverse effects such as mechanical failure. Further, methods using a spray dryer using a binder or methods in which toner and conductive powder are dispersed and adhered in a solvent and dried have the disadvantage that the manufacturing process becomes complicated.

Therefore, an object of the present invention is to provide a toner manufacturing method that solves the above problems. That is, 1) To provide a conductive toggle that is easy to manufacture and inexpensive. 2) To provide a conductive toner with excellent conductive properties and fixing properties. 3) To provide a conductive toner with excellent storage stability. 4) To provide a conductive toner with excellent fluidity. 5) To provide a stable conductive toner that does not change over time.

[Means for Solving the Problems] The toner manufacturing method of the present invention provides a conductive toner having a coating layer of a mixed system of thermoplastic resin fine particles and conductive powder surrounding particles of at least a resin and a colorant. , characterized in that the conductive layer is formed by a mechanochemical reaction.

Further, in the mechanochemical reaction, the treatment temperature X is equal to or lower than the glass transition temperature T of the thermoplastic resin fine particles of the conductive layer, and the treatment temperature
It is characterized by the above.

[Function] Since the mechanochemical reaction is a reaction that uses both thermal and mechanical energy, it is known that a resin layer is formed on the particle surface. Although there are still many unknowns regarding this point, as a result of extensive research, it has become clear that it is possible to further disperse a conductive substance in the resin coating layer. The cause of this is that the conductive substance adheres to the surface of the coating thermoplastic resin fine particles due to electrostatic force or other forces, and the thermoplastic fine particles are particles (hereinafter referred to as base particles) consisting of at least a resin and a colorant. Attach to. It is believed that the simultaneous application of thermal and mechanical energy causes the coating thermoplastic resin to melt and the photoconductive substance to be dispersed. Furthermore, since the mechanochemical reaction uses its mechanical energy to firmly adhere the conductive layer to the base particles, there is no deterioration in properties due to peeling or the like. Furthermore, since the mechanochemical reaction treatment has a granulation effect, it is thought that it can not only form a coating layer but also improve fluidity.

[Example code] The present invention will be specifically explained by the following examples.

The base particles used in the present invention have an average particle diameter of approximately 10 μm and are prepared by a general kneading and pulverization method, spray drying method, or polymerization method.
can be used. Next, thermoplastic resin fine particles and conductive powder are mixed with the mother particles prepared by a conventional method, and a conductive layer is formed on the surface of the mother particles by a mechanochemical reaction. The thickness of the conductive layer is 0.5 to 0.5 in consideration of fixing properties.
A range of 1 μm is preferred. Further, the content of the conductive substance in the conductive layer can be arbitrarily set depending on the types of resin and conductive substance. Furthermore, the treatment temperature X (°C) in the mechanochemical reaction is the glass transition temperature (in the case of a mixed system, the lower glass transition temperature) of the thermoplastic resin particles used in the conductive layer is T (°C). , T and T-10 (7
) within the range (T-10<X<T). This is because if the temperature is higher than the glass transition temperature, agglomeration of thermoplastic fine particles will occur, making it impossible to form a conductive layer. Also,
At a temperature lower than the glass transition temperature by 10° C., no thermal change is imparted to the thermoplastic resin particles, making it impossible to form a conductive layer. As a method for carrying out the mechanochemical reaction, a so-called high-speed fluidized stirrer is used. For example, Mechano Fusion System (manufactured by Kishu Micron)
, Nara Hybridization System (newly manufactured by Nara Kikai Seisakusho), etc. can be used. However, the apparatus for carrying out the mechanochemical reaction is by no means limited to these, and any apparatus other than the above-mentioned apparatus may be used as long as it is capable of applying mechanical and thermal energy.

The composition of the base particles is not particularly limited, and common compositions can be used. For example, thermoplastic resins include polystyrene and copolymers, such as hydrogenated styrene resins, styrene-isobutylene copolymers,
ABS resin, ASA resin, As resin, AASAs resin AC3 resin, ABS resin, styrene/P-chlorostyrene copolymer, styrene/propylene copolymer, styrene/butadiene crosslinked polymer, styrene/butadiene/chlorinated 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 their Copolymers, styrene/acrylic resins and their copolymers, such as styrene/acrylic copolymers, styrene/diethylamino/ethyl methacrylate copolymers, styrene/butadiene/acrylate ester copolymers, styrene/methyl methacrylate copolymers Acrylate copolymer, styrene/n-butyl methacrylate copolymer, styrene/diethylamino/ethyl methacrylate copolymer, styrene/methyl methacrylate/n-butyl acrylate copolymer, styrene/methyl methacrylate/butyl arylate/ N-(ethoxymethyl)acrylamide copolymer, styrene/glycidyl methacrylate copolymer, styrene/butadiene/dimethyl/aminoethyl methacrylate copolymer, styrene/acrylic acid ester/maleic ester copolymer, styrene/methacrylate copolymer Methyl acrylate/2-ethylhexyl acrylate copolymer, styrene/N-butyl arylate/ethyl glycol methacrylate copolymer, styrene/n
-butyl methacrylate/acrylic acid copolymer, styrene/n-butyl methacrylate/maleic anhydride copolymer, styrene/butyl acrylate/isobutyl maleic acid half ester/divinylbenzene copolymer,
Polyester and its copolymers, polyethylene and its copolymers, epoxy resins, silicone resins, polypropylene and its copolymers, fluorocarbon resins, polyamide resins,
One type or a blend of two or more types of polyvinyl alcohol resin, polyurethane resin, polyvinyl butyral resin, etc. can be used.

Also, as a waxy substance, candelilla wax,
Plant-based natural waxes such as carnauba wax and rice wax, animal-based natural waxes such as beeswax and lanolin, mineral-based natural waxes such as montan wax and osikelite, natural petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatum, and polyethylene wax. , synthetic hydrocarbon waxes such as Fujotscher-Tropsch wax, pernicious waxes such as montan wax derivatives and paraffin wax derivatives, hydrogenated castor oil,
Hydrogenated waxes such as hydrogenated castor oil derivatives, waxes such as synthetic waxes, higher fatty acids such as stearic acid and palmitic acid, low molecular weight polyethylene, oxidized polyethylene,
For low-temperature, low-pressure fixing, one or more of polyolefins such as polypropylene, olefin copolymers such as ethylene/acrylic acid copolymer, ethylene/acrylic acid ester copolymer, ethylene/vinyl acetate copolymer, etc. are added. toner can also be used as the base particle.

As the coloring agent, black dyes and pigments such as carbon black, spirit black, and nigrosine are used. In addition, magnetic agents include Fe3O4, Fe2rs, Fe, Cr, and N.
Add magnetic powder such as i, Co, etc.

Further, as a dispersant, an electron-accepting organic complex, chlorinated polyester, nitrofnic acid, quaternary ammonium salt, pyridinyl salt, etc. can be added.

Next, as the thermoplastic resin fine particles for forming a conductive layer used in the present invention, the thermoplastic resins for the base particles described above can be used in the same manner, but particularly preferably polymethyl methacrylate, polyethyl methacrylate, poly n- Butyl methacrylate, polyester, (styrene-butadiene) copolymer (PVC, PVA, PVAc) copolymer poly γ-methyl-L-glutamate, etc. are used.

In addition, as thermoplastic resin fine particles, 0.2 μm to 1 μm
A range of is preferred. Further, the conductive powder is not particularly limited, and the zero particle size using carbon black such as furnace black, lamp black, and acetylene black, and fine powder of metals and metal oxides is 0.01μ.
It is preferable to use conductive powder with particles of m-0.5 μm, more preferably 0.02 μm to 0.1 μm.

Using the method and raw materials described above, a conductive layer can be formed on the surface of the coloring and fixing mother particles.

As a result, conductive toner can be easily manufactured using a dry process.

This example will be explained in more detail below.

[Example 1] [Preparation of base particles] Styrene-acrylic copolymer 55 parts by weight Fe5O
a 40 weight 1 part nigrosine
5! Parts Using raw materials with the above composition, they are kneaded with a screw extruder, cooled, and coarsely pulverized. Next, they are finely pulverized with a jet pulverizer, and classified to a powder of 5 to 20 μm (
Mother particles with an average particle diameter of 10 μm were produced.

[Formation of conductive layer]

The conductive layer was formed using polybutyl methacrylate (PBMA) resin particles and carbon black as thermoplastic resin particles. The composition is shown below.

Base particles: 100 parts by weight PBMA fine particles: 8 parts by weight Carbon black: 10 parts by weight These raw materials were mixed and a resin-bonded conductive layer was formed on the surface of the base particles by mechanochemical reaction using a mechanofusion system (manufactured by Micron for wires). A conductive toner was prepared by forming a conductive toner.

Further, the PBMA fine particles have a particle size of 0. 2 μm, glass transition temperature is 85°C. Further, the treatment temperature was 80°C. The particle size of carbon black is 0°035 μm. The thickness of the conductive layer of the conductive toner obtained as a result is approximately 0. It was 1 μm. Also, the specific resistance of conductive toner is 1
It was 0.03ΩCm. (The specific resistance was measured by the pressure cell method. In other words, the sample was placed between two electrodes,
The resistance was measured by applying a pressure of kg/cm2. ) Next, as a guideline for fluidity, the angle of repose was measured using an electromagnetic vibration angle-of-repose measuring device. The result was 39@.

Furthermore, when the conductive toner of the present invention was used to form an image on ZnO photosensitive paper by the -component magnetic brush method, it showed excellent fixing performance at an optical temperature (hereinafter referred to as 0.D) of 1.5. I was able to form an image. Furthermore, 3
After 10,000 durability tests, it was possible to form images as clear as the initial image without any blurring or decrease in image temperature. Furthermore, when the conductive toner produced in this example was sealed in a container and stored in an environment of 30°C - 80% for 3 months and the same test as above was performed, there was no deterioration in characteristics and clear images were obtained. was able to form.

[Comparative Example 1] Using the base particles produced in Example 1, a conductive layer was formed using a zero-order Henschel mixer in which the same raw materials for forming a conductive layer as in Example 1 were mixed. When an image was formed using the conductive toner in the same manner as in Example 1, it was found that the conductive toner produced in this example had a resistivity of IQIII or more and could form an image at an angle of repose of 48°. could not.

[Comparative Example 2] In place of the Henschel mixer in Comparative Example 1, a conductive layer was formed on the surface of the base particles using a ball mill, but the results were similar to those in Comparative Example 1.

[Example 2] Conductive toner was produced in Example 1 by changing the treatment temperature of the mechanochemical reaction. The rest was carried out in the same manner as in Example 1. The results are shown in Table 1.

Table 1 In Table 1, the conductivity result O has a specific resistance of 103Ωc.
m or less. × indicates a specific resistance other than the above.

When images were formed using the conductive toners shown in Table 1 in the same manner as in Example 1, conductive toners Nos. Ta. However, No. 1. N
o, 2. For No. 5, no image could be formed.

[Example 3 The base particles of Example 1 were prepared by a spray drying method.

Using the raw material used for producing the base particles of Example 1, this was dissolved and dispersed in toluene so that the solid content was 15%. This dispersion was sprayed and granulated using a spray dryer to produce base particles. A two-fluid nozzle was used for the spraying method.

The spraying conditions were a pressure of 2 kg/cm 2 and a drying temperature of 30°C. The obtained particles are divided into 5 to 2 particles by classification.
The particles were adjusted to 0 μm (average particle size: 10 μm) and used as base particles of conductive toner. [Formation of a conductive layer] Using the above base particles, the following procedure was carried out in the same manner as in Example 1. As a result, a conductive toner similar to that in Example 1 could be obtained, and when image formation was performed in the same manner as in Example 1, a clear image similar to that in Example 1 could be formed.

[Example 4] [Preparation of base particles] Paraffin wax 40 wt% ethylene/vinyl acetate copolymer 10 wt% carbon black 4 wt% F esoa
Using a raw material having the above composition of 46 wt%, it is kneaded in a screw extruder, cooled, and coarsely ground. Next, it is finely pulverized with a jet pulverizer, classified, and
A toner of 20 μm (average particle size 10 μm) was produced.

[Formation of conductive layer]

The conductive layer was formed using polybutyl methacrylate (PBMA) resin particles and carbon black as thermoplastic resin particles, and six compositions are shown below.

Base particle 100wt%PBMA
Fine particles 27wt% carbon black
19 wt % of these raw materials were mixed, and a conductive layer was formed on the surface of the base particles by mechanochemical reaction in the same manner as in Example 1 to produce a conductive toner. PBMA
The particle size of the fine particles is 0. 4 μm, otherwise the same as in Example 1. As a result, the thickness of the conductive layer is 0. The conductive toner produced in this example was evaluated in the same manner as in Example 1. As a result, the specific resistance was 103 Ωcm and the angle of repose was 39°. Furthermore, when image formation was performed in the same manner as in Example 1, the same results as in Example 1 were obtained. Also,
Using the conductive toner produced in this example, a solid image is formed on an insulating film by a -component magnetic brush development method without applying a bias voltage, and is thermally fixed to form an ink sheet for thermal transfer. was able to be created.

Therefore, the toner produced in this example can also be used as an inking material for regenerative thermal transfer.

[Comparative Example 3] The conductive layer of Example 4 was formed in the same manner as Comparative Examples 1 and 2. As a result, the base particles agglomerated and could not even be obtained as a powder.

Although the examples of the present invention have been shown above, the conductive toner of the present invention is not limited to these examples, and furthermore, the conductive toner produced by the manufacturing method of the present invention can be used in the image formation of this example. The present invention is not limited to any particular method, and can be used in any image forming method using conductive toner.

[Effects of the Invention] As described above, according to the toner manufacturing method of the present invention,
By forming a conductive layer made of a mixed system of thermoplastic resin fine particles and a conductive substance on the surface of particles made of at least a resin and a coloring agent through a mechanochemical reaction, processing can be performed in a short time and with energy savings, and furthermore, post-treatment classification, etc. Since this operation is unnecessary, the conductive toner can be manufactured very easily, and the conductive toner can be provided at low cost. Furthermore, the resulting conductive toner has unprecedented advantages in that it has excellent conductivity and fixing properties, as well as excellent storage stability, fluidity, and stability.

The toner manufacturing method of the present invention can also be applied to conductive toner used in copying machines, printers, facsimile machines, and the like.

that's all Applicant: Seiko Epson Corporation

Claims (2)

[Claims] (1) In a conductive toner in which particles made of at least a resin and a colorant are coated with a mixed system made of thermoplastic resin fine particles and a conductive substance as a conductive layer, the conductive layer is formed by a mechanochemical reaction. A method for producing a toner, characterized by: (2) In the mechanochemical reaction, the treatment temperature X is equal to or lower than the glass transition temperature T of the thermoplastic resin fine particles of the conductive layer, and the treatment temperature
The method for manufacturing a toner according to claim 1, wherein the method is as follows.