JPS6026352A - Magnetic color toner - Google Patents

Abstract

PURPOSE:To improve developing performance, transferability, and fixability, obtain an image sharp in hue, and enable application to vapor phase transfer to TP by incorporating a magnetic powder specified in size distribution and a dye compatible with a binder resin. CONSTITUTION:A magnetic powder has a size distribution having 1.5-6.5mum diameter of particles of 50 integrated vol%; 1.0-5.5mum diameter of particles of 25vol%; and 2.5-7.5mum diameter of particles of 75vol%. The toner has a melt flow index (MFI)- I of 1.5-2.0, and a ratio of (MFI)- I to (MFI)-II in the case of contg. no dye, of 1.0-7.0. As a result, the magnetic powder can be uniformly dispersed into the toner particles by using such a size distribution, and deterioration of image quality and background staining can be prevented under low humidites, coloring due to the magnetic powder is not so high, and coloring with a colorant is made easy. The use of a dye having a I /II ratio of MFI of 1-7, i.e. one high in compatibility improves fluidity at the time of hot fixing, it is also applicable to TP, and offset and adhesion to a heating roller are prevented, and a sharp color image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc., and particularly relates to a magnetic color toner.

Conventionally, as an electrophotographic method, U.S. Patent No. 2,297.69
Although many methods are known, as described in Japanese Patent Publication No. 1, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748, etc., they generally utilize photoconductive substances and perform various methods. The method includes forming an electrical latent image on a single-color photoreceptor, then developing the latent image using toner, and transferring the toner image to a transfer material such as paper as necessary, by applying heat, pressure, or Copies are obtained by fixing with solvent vapor or the like.

The electronic printing method, as proposed in Japanese Patent Publication No. 4214342 and others, is a method of guiding and fixing charged powder toner onto a recording material using an electric field for printing.

The electrostatic recording method is a method in which a charge is applied to a dielectric layer in the form of an image, and a charged toner powder is attached and fixed thereon. Similarly, the magnetic printing method is a method in which a magnetic latent image is formed on a recording material. is formed and developed with toner powder containing magnetic material,
This is a method of transferring and fixing onto a transfer material.

Various developing methods are known for visualizing such electrical or magnetic latent images using toner, and they can be broadly classified into dry developing methods and wet developing methods. The former method is further divided into a method using a two-component developer using carrier particles and a method using a single-component developer not using carrier particles.

Among the two-component developing methods, the magnetic plan method using an iron powder carrier and the cascade method using a bead carrier are widely put into practical use, depending on the type of carrier for conveying the toner.

On the other hand, various development methods have been proposed that use one-component developers that provide good toner quality, but among these, many excellent methods using magnetic toner have been put into practical use. Development methods using magnetic component developers include the MagneDry method using conductive toner, the method using dielectric polarization of toner particles disclosed in JP-A No. 52-94140, and the method using dielectric polarization of toner particles disclosed in JP-A-52-94140;
The method of charge transfer by toner disturbance disclosed in Japanese Patent Publication No. 31136, as well as the excellent developing method recently proposed by the present applicant, are disclosed in Japanese Patent Laid-Open No. 54-42141 and Japanese Patent Laid-open No. 55-1.
Recently, electrophotography, such as the above-mentioned electrophotography, has been used for a wide variety of purposes, and small and inexpensive color images such as the one disclosed in Japanese Patent Application No. 8656, which fly toner particles against a latent image, can obtain images of desired colors as needed. The copier for copying is out of stock.

The above-mentioned magnetic component development method is suitable for small and inexpensive copying machines, but magnetic component toner has conventionally used magnetite or ferrite as its magnetic material, and the color of these magnetic materials has been limited. is black or dark brown, and is effective for obtaining black toner, but has been a major obstacle for obtaining so-called color toner.

To overcome this obstacle, the black magnetic material was made white.
, or coloring is described in Japanese Patent Application Laid-open No. TL/(51-425
No. 39, No. 51-46131, and the like. However, in the above method, since the magnetic substance contained in the toner is a fine powder, the whitening and coloring methods are difficult, and the process becomes complicated and expensive. Another drawback was that the color of the magnetic material could not be erased unless a large amount of coloring agent was used.

On the other hand, a method of increasing the particle size of the magnetic material to reduce the coloring power of the magnetic material was considered, but since large magnetic materials tend to exist non-uniformly in the resin, the developability of magnetic toner, such as deterioration of image quality, and magnetic There were drawbacks such as image deterioration in durability due to background smearing due to particles that do not contain particles.

Previously, the present applicant has overcome the above-mentioned drawbacks when conductive fine particles are contained for the purpose of reducing the charge association of a magnetic material, a binder resin, and a toner having at least a certain particle size and a certain particle size distribution. Although it has been found that a magnetic color toner can be obtained, the color is still unsatisfactory, and in particular when applied to OHP, the current situation is that only very unsatisfactory colors can be obtained.

The reason for this is that toner particles on transparency (TP) remain particulate even after fixing, so when applied to OHP, light is not only absorbed by toner particles but also reflected and refracted. The main reason is that the amount of light decreases and the entire visible light range becomes darker.

As a result of intensive studies to improve the above properties, the present inventors have found that a magnetic toner containing at least a binder resin and magnetic powder contains a dye that is compatible with the binder resin as a coloring agent. It has been discovered that a magnetic color toner having the above-mentioned properties can be obtained.

That is, an object of the present invention is to provide a magnetic color toner that has further improved properties as described above and can produce images with vivid colors.

Furthermore, it is an object of the present invention to provide a magnetic color toner that can be produced easily and inexpensively.

A further object of the present invention is to provide a magnetic color toner that has even better developability, transferability, and fixability.

A further object of the present invention is to provide a magnetic color toner that can be applied to vapor phase transfer to TP.

The present invention is characterized in that, in a magnetic toner containing at least a magnetic powder, a binder resin, and a dye, the volume-based integrated diameter of the magnetic material is 1.5 to 6.5 μ, 25 qb.
The diameter is 1. o~5.5μ, 75mm diameter is 2.5~7.5μ
This is a magnetic color toner characterized by having a particle size distribution of .

The magnetic powder used in the present invention is 50% by volume
The diameter is 1.5 to 6.5μ, and the diameter of 25mm is 1.0 to 5.5μ.
.

There are powders of ferromagnetic elements having a particle size distribution of 2.5 to 7.5μ, and alloys and compounds containing these, such as alloys and compounds of iron, cobalt, nickel, and manganese such as magnetite, γ-hematite ferrite, etc. There are other ferromagnetic alloys that are conventionally known as magnetic materials, but magnetite and the like are particularly suitable for blue or edge threads, and γ-hematite and the like are suitable for yellow or red magnetic toners.

The reason why the particle size range of the magnetic material used in the present invention is shown above is that if the particle size of the magnetic powder is larger than this, it will be easier to color with the colorant, but the magnetic powder in the toner particles will be more easily colored. The dispersion tends to be non-uniform, and toner particles that do not contain a magnetic substance are also easily formed, resulting in deterioration in image quality and background smearing, which tends to be particularly strong in low-humidity environments.

On the other hand, if the particle size of the magnetic material is smaller than these ranges, coloring by the magnetic material will be strong, making it difficult to color with a coloring agent other than the magnetic material, and at the same time, the fixing temperature will be high and the fixing performance will be reduced.

The above magnetic material can be manufactured by any of the following methods: pulverization, particle growth during wet sedimentation, sintering of the magnetic material, or particle growth using flux. The sintering method or the flux method is preferable because it allows narrowing the area.

Furthermore, the most preferable manufacturing method for these magnetic materials is the sintering method, specifically approximately 0.3 to 1.0
cl of μ, -Fe2O3f 1000-110
(Heat to 1°C to sinter, then mechanically crush. Depending on the requirements, wet classification through a 400-200 mesh filter.Furthermore, the obtained powder is heated to 250-500°C, water bed, It is reduced with propane, etc. After that, it is crushed to obtain magnetic powder used in the present invention.Furthermore, the magnetic powder may be surface-treated if necessary.

In addition, in the present invention, the particle size distribution of the magnetic powder is
The measurement was carried out under appropriate conditions using a counter model TA-nlJ and a 50 μm diameter anno-char tube.

Further, the present invention provides a magnetic color toner containing at least a binder resin, magnetic powder with a large particle size, and a dye, in which a dye that is particularly compatible with the binder resin is contained as the dye, thereby reducing melt flora. Index CMI value>
is in the range of 1.5 to 20 (preferably 2.0 to 15.0) at 125° C. and 10 kg load, and is the same as the above toner except that the MI value (1) of the above magnetic color toner and no dye are contained. The ratio I/II of the melt 70 wind index (11) of the paste material is 1.0 to 7.0 (preferably 1
．． 2 to 5.0). .

The reason why the MI value is within this range is that if the MI value is smaller than this, the fluidity during heat fixing will not be sufficient and the toner will exist in the form of particles, making it impossible to obtain a clear color image. , Also, if it is larger than this, there will be an offset during heat fixing,
This is because troubles such as wrapping occur.

The method for measuring the melt flora index of the present invention is carried out in accordance with method A of JIS 7210. The measurement conditions are a temperature of 125° C. and a load of 10 kg.

The magnetic color toner of the present invention contains at least a binder resin, magnetic powder, and dye, and the composition ratio is 20 to 120 parts by weight of the magnetic powder to 100 parts by weight of the binder resin! i part (preferably 40-807 M m 815).

Dye o, i - 20 parts by weight (preferably 1-15 parts by weight)
0.1 to 2.0 parts by weight (preferably 0.2 to 1.0 parts by weight) of colloidal silica and 0.01 to 5 parts by weight (preferably 0.02 to 1.0 parts by weight) of colloidal silica and conductive fine particles are preferably added as necessary.
05 to 2 parts by weight) may be added.

As the binder resin used in the present invention, 1. +5 listerene, poly p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymer.

Homopolymers of styrene and its substituted products, such as styrene-vinyltoluene copolymers, and copolymers thereof, styrene-methyl acrylate copolymers, styrene-acrylic acid-n.
Copolymers of styrene and acrylic esters such as butyl copolymers, styrene and methacrylates such as styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate copolymers, and styrene-n-zotyl methacrylate copolymers. Copolymers with acid nysder, multicomponent copolymers of styrene with acrylic esters and methacrylic esters, and other styrene-acrylonitrile copolymers.

Styrene such as styrene-vinylmethylnyf,11/copolymer, styrene-butadiene copolymer, styrene-vinylmethylchthone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleate ester copolymer, etc. Styrenic copolymers with other vinyl monomers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyesters, polyamides, epoxy resins.

Known binding substances such as folivinylpetyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon resin, 2 petroleum resin, and chlorinated/9 rough-in can be used alone or in combination.

Furthermore, as binder resins for toners used in pressure fixing systems, low molecular weight polyethylene, low molecular weight polypropylene, ethylene vinyl acetate copolymers, ethylene vinyl acetate copolymers, ethylene acrylic acid ester copolymers, and higher fatty acids are used. , polyamide resin, polyester resin, etc. can be used alone or in combination.

The coloring agent used in the present invention is compatible with the binder resin,
Although any dye that increases the MI value can be used, it is preferable to use sublimable dyes that can sublime at approximately 100-250° C. in view of their applicability to color OHPs. For example, Kayalon Fast Yellow 4 R (C, 1,260
90), Kayalon Fast Yellow G (C, 1, 11
855), Kayalon Fast Brown R (C.

1.11100), Kayalon Fast Troupin B (
C.I.

11115) and above, manufactured by a certain Nippon Kaisha, Mikuton First Scarlet n (C, 1, 11110), Miketon First Bi/Li RL (C, 1, 60755), Miketo/7 Earth Brilliant Blue B (C, 1, 6150)
5), Miketone First Turquoise Blue G (C,
I, 62500), Miketon Polyester Yellow 5 R (C, 1, 26090) or higher manufactured by Mitsui Toatsu Co., Ltd., Sumikaron Yellow FG (C, 1, 12690), Sumikawa/Orange FG (C, 1, Dispers@Ora
nge20), Sumikaron Red 3 B R (C, I
, Dl 5perseRad65), Sumikaronno Iolet R (C,I.

Disperte Violet 23), Sumikalon Blue BR (C, 1, 63305) manufactured by Sumitomo Chemical Co., Ltd., etc.

In addition, the toner of the present invention may further contain a fixing aid such as low molecular weight polyethylene and a rough abrasive such as cerium oxide, if necessary. .

After kneading the constituent materials using a heat mixer or an extruder, mechanical crushing or classification may be used, or by dispersing materials such as magnetic powder in a binder solution. A polymerized toner is obtained by spray-drying, or by mixing a predetermined material with a monomer to constitute a binder resin, and then polymerizing the milk suspension to obtain a magnetic toner. Each manufacturing method can be applied.

In the present invention, the particle size distribution of the magnetic powder was measured under appropriate conditions using a Coulter counter model TA-II model and an aperture tube with a diameter of 50 μm.

Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto in any way. In addition, all parts in the following formulations are Towaru parts.

Example 1 Styrene-butyl acrylate-butyl maleate (70
:25:5) Copolymer ioo part magnetic powder (magnetite volume based integrated 50% diameter 5.16μ, 25% diameter 4.38μ
, 75 inches diameter 6.05μ) 60 parts Ce1liton D
iaclxarge Blue FFR (C, 1, 11
410) 10 parts The above mixture is kneaded at 150° C. in a roll mill, and after cooling, coarsely ground in a speed mill. Thereafter, the powder was finely pulverized using a jet mill, and a powder of 5 to 20 μm was obtained using an air classifier, and 0.5 part of colloidal silica was added thereto to obtain a blue magnetic toner having an MI value of 6.8. The MI value of the dye-free paste material at this time was 1.6, and the MI value ratio was 4.3.

This magnetic color toner is applied to a commercially available plain paper copier (product name:
NP-200J (manufactured by Canon) was used to produce an image, and a very clear, high-density blue image was obtained. Furthermore, when 100 copies were made continuously, clear images with high density were obtained, and there was no change in color tone.

Furthermore, the plain paper image and TP were overlapped and heated to 200℃6.
When vapor phase transfer was performed for 0 seconds, a very clear and highly concentrated blue OHP was obtained.

Comparative Example 1 The following magnetic powder was used as the magnetic powder (magnetite, volume-based integrated 50mm diameter: 1.88μ, 25mm diameter: 1.49μ.

When a magnetic toner with an MI value of 3.5 was obtained in the same manner as in Example 1, except that a magnetic toner with an MI value of 3.5 was used, only a slightly bluish black image was obtained, and the high temperature In addition, the image density decreased under humidity (30°C, 90% RH).At this time, the MI value ratio with the base material was 3.5/1.2=
It was 2.9.

Furthermore, when I tried vapor phase transfer from a plain paper image to TP, I found that the color 〇HP was very clear but had low density.
I couldn't get it.

Comparative Example 2 The following magnetic powders (Magnetite, volume-based integration, 50mm diameter 6.55μ, 25mm diameter 5.10μ) were used as magnetic powders.

A blue magnetic toner with an MI value of 8.6 was obtained in the same manner as in Example 1, except that a 75 mm (diameter: 7.60 μ) was used, and when image printing was performed, a very clear blue image was obtained. , image quality deteriorated during continuous copying, especially in low humidity environments.

At this time, the ratio of MI value to the base material was 8.6/2.
3=3,7.

Example 2 Also, as a coloring agent, the dye Ceressol R (C, I.

Disperse Blue 14) A blue magnetic toner with an MI value of 7.6 was obtained in the same manner as in Example 1 except that 't' was used. A blue image was obtained.

At this time, the ratio of MI value to the base material is 7.6/1.6=
It was 4.8.

Example 3 Styrene-butyl acrylate (70:30) copolymer
100 parts magnetic powder (magnetite, volume-based cumulative 50 cm diameter 5.16
μ, 25% diameter 4.38μ, 75% diameter 6.05μ) 60 copies Kayiset Blue 136 (manufactured by Nippon Kaisha)
A blue magnetic toner with an MI value of 9.2 was obtained in the same manner as in Example 1 by using 10 parts and 4 parts of polypropylene and adding 0.5 parts of colloidal silica. Very clear and high density images were obtained. At this time, the ratio of MI value to the base material was 9.2/6. O=1.5.

Furthermore, when vapor phase transfer was performed on TP, a very clear, high-density color OHP without blackness was obtained.

Example 4 Styrene-butyl methacrylate (75:25) copolymer ioo part magnetic powder (γ-Fe203 + volume-based integrated 50 mm diameter 4.8
6μ.

25% diameter 4.10μ, 75qb diameter 5.12μ) 70 parts Kayaaet Red 130 (manufactured by Nippon Kaisha)
A red magnetic toner with an MI value of 5.4 was obtained in the same manner as in Example 1 by using 4 parts of 5 parts polyzologylene and adding 0.6 parts of colloidal silica.
When image printing was carried out, a very clear and high-density red image was obtained as in Example 1. MI with the base material at this time
The ratio of the values was 5.4/2.6=2.1)-1. Furthermore, when vapor phase transfer was performed on TP, a very clear, high-density color 〇IP with no blackness was obtained.

Shinbu Kosenq 1i1Jlii1,

Claims (1)

[Scope of Claims] 1. In a magnetic toner containing at least magnetic powder, a binder resin, and a dye, the volume-based integrated 50-inch diameter of the magnetic material is 1.5 to 6.5 μ, and the 25-diameter is 1. 0-5.5μ, 7
A magnetic color toner characterized by having a particle size distribution of 2.5 to 7.5 microns in diameter. 2. Melt flora index (I) is 1.5-20
and the melt flora index of the toner (
The ratio (1/
11) The magnetic color toner according to claim 1, wherein 11) is 1.0 to 7.0.