JPH04232965A - dry toner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry toner for developing electrostatic images formed in electrophotography, electrostatic recording, etc.

0002

BACKGROUND OF THE INVENTION The average particle diameter of toners commonly used in the past has been decreasing as copying quality has improved. Toners with an average particle size of up to around 9 μm have been manufactured by the commonly used kneading, pulverizing and classification method, but in the case of toners with an average particle size of less than 9 μm, the classification yield is significant when using the pulverizing method. Since the toner deteriorates, it is not suitable for production, and instead, toner has been produced by a polymerization method. On the other hand, methods for producing toner particles by polymerization include suspension polymerization, solution polymerization, and emulsion polymerization, but all polymerization methods can relatively easily produce toner particles with an average particle diameter of 8 μm or less. be able to.

0003

However, a drawback in producing toner by the polymerization method is that toner particles are obtained by granulation, so the particles themselves are closer to spherical than kneaded, crushed and classified toner which has an irregular shape. Therefore, in the cleaning process after the development and transfer process in the copying machine, since the toner particles are small in diameter and nearly spherical, they tend to pass through the cleaning blade, resulting in poor cleaning.

0004

[Means for Solving the Problems] As a result of various studies to solve the above-mentioned problems, the present invention has solved the problems with the following configuration. That is, the average particle size produced by polymerization method is 3 to 8.
For polymerized toner particles of 0.1 to 20 μm, crushed toner particles with an average particle diameter of 10 to 20 μm produced by a pulverization method are
By adding 20% by weight, it was possible to prevent the toner from slipping through the cleaning blade and solve the problem of poor cleaning.

[0005] As a method for producing toner particles by a polymerization method, an emulsion polymerization method is mentioned, and the outline thereof is, for example, a styrene acrylic monomer, carbon black, a charge control agent,
Add a low molecular weight polypropylene resin for offset prevention and an emulsifier and perform a premix. Next, set the above premix in a reaction vessel, add a polymerization initiator, and heat at 100°C.
Polymerizes with At this time, the toner particles are small, around 1 μm, but particles of several μm to 10 μm can be obtained by granulation. Further, by ripening, particles with even larger particle shapes can be obtained. Next, wash with water to remove the emulsifier, and use a dehydrator (
Remove water using a centrifuge (centrifuge). The toner particles are then dried using a vacuum dryer or the like to obtain the desired toner particles.

[0006] Another method for producing toner particles using a polymerization method is the suspension polymerization method, which basically involves adding a dispersant to water, and adding, for example, styrene acrylic monomer, carbon black, a charge control agent, and a low molecular weight A polypropylene resin is added and premixed, then the above premixed product is placed in a reaction vessel and prepolymerized, a polymerization initiator is added and main polymerization is carried out at about 100°C. After that, it is washed with water and the moisture is removed using a dehydrator (centrifuge). The toner particles are then dried using a vacuum dryer or the like to obtain the desired toner particles.

[0007] Still another method for producing toner particles using a polymerization method is the solution polymerization method, which is basically a method similar to the suspension polymerization method, in which a solvent is used in place of water in the suspension polymerization method. They are different in terms of usage, but the details are omitted.

Next, toner particles produced by the pulverization method can be produced by the following method. It is manufactured by mixing a binder resin, a coloring agent, a charge control agent, and other additives added as necessary in a desired formulation, melting and kneading, and then crushing and classifying.

The above-mentioned binder resins are generally known as binder resins for toners, such as styrene resins, polyacrylic ester resins, styrene-acrylic ester copolymer resins, polyvinyl chloride, and polyvinyl chloride. Examples include vinyl acetate, polyvinylidene chloride, phenol resin, epoxy resin, polyester resin, and the like.

[0010] As the colorant, those generally used as colorants for toners can be used, such as carbon black, monoazo red pigment, disazo yellow pigment, quinacridone magenta pigment, anthraquinone dye, etc. Can be mentioned.

Furthermore, when the carrier is positively charged as a charge control agent, nigrosine dyes,
Examples include alkoxylated amines, quaternary ammonium salts, alkylamides, etc. In addition, when negatively charged, metal complex salts of monoazo dyes, electron-accepting organic complexes, chlorinated polyolefins, etc. are used depending on the desired chargeability. It can be used as appropriate. Other additives that may be added as necessary include offset inhibitors such as low molecular weight polypropylene resins, powders of polystyrene and polyacrylic resins, powders of titanium dioxide, conductive titanium, zinc, etc., and powders of higher fatty acids. Examples include lubricants such as metal salts, and fluidizing agents such as hydrophobic silica and colloidal silica.

0012

[Operation] Small-diameter toner produced by the polymerization method easily passes between the cleaning blade and the photoreceptor. In contrast, in the present invention, by adding an amorphous toner produced by a pulverization method, this pulverization toner is present between the cleaning blade and the photoreceptor, thereby preventing small particle size toner from passing through the cleaning blade. It was possible to improve cleaning defects.

In the present invention, the amount of pulverized toner particles added to the polymerized toner particles is 0.1% to 20% by weight.
If it is less than 0.1% by weight, the amount of crushed toner that accumulates on the cleaning blade will be small, and it will not be possible to prevent small-sized polymerized toner from passing through the cleaning blade. If the amount exceeds 20% by weight, the quality of the copied image cannot be improved, and the purpose of making the toner smaller in particle size cannot be achieved.

Further, in the present invention, it is necessary that the average particle diameter of the polymerized toner particles is 3 to 8 μm, and the average particle diameter of the pulverized toner particles is 10 to 20 μm. In this case, the average particle diameter is 5 by volume based on Coulter counter.
This is the measured value at 0%. In this case, if the average particle diameter of the polymerized toner particles is less than 3 μm, stable manufacturing conditions cannot be obtained, and if it exceeds 8 μm, high resolution image quality cannot be obtained. On the other hand, if the average particle diameter of the crushed toner particles is less than 10 μm, the effect of improving cleaning performance cannot be obtained;
If it exceeds m, high quality copy images cannot be obtained. Furthermore, in the present invention, the polymerized toner particles and the pulverized toner particles both contain the same charge control agent and have the same charge polarity and charge amount, which imparts stable chargeability to the dry toner of the present invention. preferred for.

[0015]

[Manufacture of polymerized toner particles]

styrene monomer
80 parts by weight Butyl acrylate monomer
8 parts by weight
polypropylene monomer
5 parts by weight
Carbon black (Mitsubishi Kasei #30)
5 parts by weight Chromium-containing metal dye (E-81 manufactured by Orient Kagaku Kogyo Co., Ltd.) 2 parts by weight The above formulation was put into a polymerization pot together with a polymerization initiator, and while polymerization was started, granulation was proceeded with carbon black and charge control agent particles, and the average When the particles were granulated to a particle size of 6 μm, a polymerization terminator was added to stop the polymerization. After that, the granulated particles were washed with water and dried to obtain an average particle size of 6μ by the polymerization method.
m negatively chargeable polymerized toner particles were obtained.

[Manufacture of pulverized toner particles] Styrene-acrylic copolymer resin
88 parts by weight
(CPR-100 manufactured by Mitsui Toatsu Chemical Co., Ltd.) Polypropylene resin
5 parts by weight (
Hymer 330P manufactured by Sanyo Chemical Co., Ltd.) Carbon black
5 parts by weight
(Mitsubishi Kasei #30)
Chromium-containing dye
2 parts by weight
(E-81 manufactured by Orient Kagaku Kogyo Co., Ltd.) The above-mentioned mixture was kneaded using two pressure rollers, and negatively charged pulverized toner particles having an average particle diameter of 15 μm were obtained using a jet mill type pulverizer and a classifier. Next, 5% by weight of pulverized toner particles were added to the polymerized toner particles and stirred with a Henschel mixer to obtain a dry toner of the present invention.

Example 2 [Production of polymerized toner particles] Styrene monomer
75 parts by weight Butyl acrylate monomer
12 parts by weight
polypropylene monomer
3 parts by weight
Carbon black (Mitsubishi Kasei #30)
8 parts by weight Chromium-containing metal dye (E-81 manufactured by Orient Kagaku Kogyo Co., Ltd.) 3 parts by weight The above formulation was put into a polymerization pot together with a polymerization initiator, and while polymerization was started, granulation was proceeded with carbon black and charge control agent particles to form average particles. When the particles were granulated to a diameter of 5 μm, a polymerization terminator was added to stop the polymerization. Thereafter, the granulated particles were washed with water and dried to obtain negatively chargeable polymerized toner particles having an average particle diameter of 6 μm.

[Manufacture of pulverized toner particles] Styrene-acrylic copolymer resin
87 parts by weight
(CPR-100 manufactured by Mitsui Toatsu Chemical Co., Ltd.) Polypropylene resin
3 parts by weight (
Hymer 330P manufactured by Sanyo Chemical Co., Ltd.) Carbon black
8 parts by weight (Mitsubishi Kasei #30) Chromium-containing metal dye
3
Parts by weight (E-81 manufactured by Orient Chemical Industry Co., Ltd.
) The above mixture was kneaded using two pressure rollers, and a jet mill type pulverizer and a classifier were used to obtain negatively chargeable pulverized toner particles having an average particle diameter of 12 μm. Next, 10% by weight of pulverized toner particles were added to the polymerized toner particles and stirred with a Henschel mixer to obtain a dry toner of the present invention.

Example 3 [Production of polymerized toner particles] Styrene monomer
78 parts by weight Butyl acrylate monomer
12 parts by weight
polypropylene monomer
5 parts by weight
Carbon black (Mitsubishi Kasei #30)
5 parts by weight Nigrosine dye
2 parts by weight (Bontron N-07 manufactured by Orient Chemical Industry Co., Ltd.) The above formulation was placed in a polymerization pot together with a polymerization initiator, and while polymerization was initiated, granulation was proceeded with carbon black and charge control agent particles until the average particle size was 6 μm. By the way, a polymerization terminator was added to stop the polymerization. Thereafter, the granulated particles were washed with water and dried to obtain positively chargeable polymerized toner particles having an average particle diameter of 6 μm.

[Manufacture of pulverized toner particles] Styrene-acrylic copolymer resin
88 parts by weight
(CPR-100 manufactured by Mitsui Toatsu Chemical Co., Ltd.) Polypropylene resin
5 parts by weight (
Hymer 330P manufactured by Sanyo Chemical Co., Ltd.) Carbon black
5 parts by weight (Mitsubishi Kasei #30) Nigrosine dye
2 parts by weight (Bontron N-07 manufactured by Orient Chemical Industry Co., Ltd.) The above mixture was kneaded using two pressure rollers, and positively charged pulverized toner particles with an average particle diameter of 15 μm were obtained using a jet mill type pulverizer and a classifier. . Next, 5% by weight of pulverized 15 μm toner particles were added to the polymerized toner particles and stirred with a Henschel mixer to obtain a dry toner of the present invention.

Example 4 [Production of polymerized toner particles] Styrene monomer
74 parts by weight Butyl acrylate monomer
12 parts by weight
polypropylene monomer
3 parts by weight
Carbon black
8 parts by weight
(Mitsubishi Kasei #30) Chromium-containing dye
3
Parts by weight (E-81 manufactured by Orient Chemical Industry Co., Ltd.
) The above formulation was put into a polymerization pot together with a polymerization initiator, and while polymerization was started, granulation was proceeded with carbon black and charge control agent particles, and when the particles were granulated to an average particle size of 5 μm, a polymerization terminator was added to stop the polymerization. Thereafter, the granulated particles were washed with water and dried to obtain negatively chargeable polymerized toner particles having an average particle diameter of 6 μm.

[Production of pulverized toner particles] Styrene-acrylic copolymer resin
86 parts by weight
(CPR-100 manufactured by Mitsui Toatsu Chemical Co., Ltd.) Polypropylene resin
3 parts by weight (
Hymer 330P manufactured by Sanyo Chemical Co., Ltd.) Carbon black
8 parts by weight (Mitsubishi Kasei #30) Nigrosine-containing dye
3 parts by weight (E-81 manufactured by Orient Chemical Industry Co., Ltd.)
The above mixture was kneaded using two pressure rollers, and a jet mill type pulverizer and a classifier were used to obtain negatively chargeable powder toner particles having an average particle diameter of 12 μm. Next, 10% by weight of pulverized toner particles were added to the polymerized toner particles and stirred with a Henschel mixer to obtain a dry toner of the present invention.

As for the two-component developer, silicon coated ferrite carrier F-96 manufactured by Powder Tech Co., Ltd.
-100 and a toner concentration of 4% by weight were prepared and tested. For Examples 1 and 2, a 100,000-sheet photocopy test was conducted using a commercially available copying machine, Ricoh FT-4030 (selenium photoreceptor). In addition, for Examples 3 and 4, Sharp SF-5800 (OPC photoreceptor)
We conducted a 100,000-shot live-action test.

Comparative Example 1 Negatively chargeable polymerized toner having an average particle diameter of 6 μm produced by the polymerization method in Example 1 and silicone coated ferrite carrier F-96-1 manufactured by Powdertech Co., Ltd.
00 to make a developer, and replenish toner with an average particle size of 6 μm produced by a polymerization method.
A 100,000-shot live-action test was conducted with the T-4030.

Comparative Example 2 A developer was made from the negatively chargeable toner with an average particle diameter of 5 μm produced by the polymerization method prepared in Example 2 and silicone coated ferrite carrier F-96-100, and the replenishment toner was also a toner produced by the polymerization method of 5 μm. A 100,000-sheet photocopy test was carried out using a commercially available copying machine, FT-4030 manufactured by Ricoh Co., Ltd.

Comparative Example 3 A developer was prepared using the negatively charged polymerized toner produced in Example 3 with an average particle diameter of 6 μm using the polymerization method and silicone coated ferrite carrier F-95-100. After replenishing toner, a 100,000-sheet photocopy test was conducted using a commercially available copier ST-8800 manufactured by Sharp Corporation.

Comparative Example 4 Toner with an average particle diameter of 6 μm produced by the polymerization method in Example 3 and silicon coated ferrite carrier F-96-
100 was prepared, and toner with an average particle diameter of 6 μm obtained by polymerization was replenished, and a 100,000-sheet photocopying test was conducted using a commercially available copying machine ST-8800 manufactured by Sharp Co., Ltd. The actual test results are shown in Table 1.

[0028]

[Table 1]

Looking at the above results, compared to the polymerized toner particles of Examples 1 to 4, the toners to which pulverized toner particles were added had no cleaning defects and produced good images even in an actual machine printing test of 100,000 sheets. quality was obtained. Comparison 01~
It was found that toners containing only polymerized particles up to No. 4 were unusable due to significant cleaning failure in actual machine printing tests after 100,000 sheets. The evaluation method for each characteristic is as follows. Measurement of image density: Macbeth density meter Measurement of background fog: Hunter color difference meter Measurement of toner charge amount: Toshiba blow-off charge amount measurement device Judgment of cleanability: Make a copy using a solid white original and make a copy at that time
- Visually inspected the dirt on the top and found that cleaning was inadequate.
Evaluate.
○─There are no stains on the copy.
△─Some dirt appears on the copy
×─ Significant stains appear on the copy

[0030]

[Effects of the Invention] According to the present invention, since the toner is composed of polymerized toner particles and pulverized toner particles in an appropriate ratio, cleaning properties are improved and a toner that provides good image quality is provided. I was able to do that.

Claims (1)

[Claims] [Claim 1] Average particle size of 3 or more produced by a polymerization method.
For polymerized toner particles of 8 μm, crushed toner particles with an average particle diameter of 10 to 20 μm produced by a crushing method were mixed with 0.1 to 2 μm of polymerized toner particles.
2. The dry toner according to claim 1, wherein the polymerized toner particles and the pulverized toner particles both contain the same charge control agent and have the same charge polarity. dry toner.