JPH02297562A - Color toner - Google Patents

Abstract

PURPOSE:To obtain sufficient coloring power and the good transparency of images on an OHP film by specifying the number average particle size of the pigments in toner particles to 20 to 300mmu and the standard deviation of dispersion to <=50mmu and forming the toner particles to a spherical shape. CONSTITUTION:The number average particle size of the pigments in the toner particles contg. the chromatic pigments in a dispersed state as coloring agents is specified to 20 to 300mmu and the standard deviation of dispersion to <=50mmu. In addition, the toner particles are formed to the spherical shape. The spherical shape refers to the shape having no angles on the toner surface when macroscopically viewed. The shapes where angles and wave shapes exist at microscopically view are included in the spherical as well. The sharp copied images having no fogging are obtd. in this way and the excellent transparency is exhibited particularly with the overhead projector (OHP) film. This toner is adequate for the reflection type OHP as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color toner used in a method for visualizing a latent image.

[Prior Art] As a method for forming and recording images, for example, electrophotography, many methods are known, as described in U.S. Pat. No. 2,297,691, etc. Generally, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the latent image is developed using toner, and if necessary, the toner image is transferred to a transfer member such as paper. After transcribing the
A copy is obtained by fixing by heat, pressure, solvent vapor, etc.

Various methods have been proposed in the past for developing with toner and fixing, and are used as needed. In addition, in order to obtain a multicolor image, the original is exposed using a color separation filter, the above process is repeated multiple times using color toners such as yellow, magenta, and cyan, and the toner images are superimposed. This is a color image.

Generally, a toner is obtained by melt-mixing a colorant in a thermoplastic resin, uniformly dispersing the mixture, and then adjusting it to a desired particle size using a pulverizer/classifier.

Although this manufacturing method can produce quite good toners, it has certain limitations, namely the range of choices of materials for the toner. It must be able to be finely pulverized. Naturally, a brittle resin colorant dispersion is selected,
In fact, the problem arises that, when milling at high speeds, particles with a wide size range are likely to be formed, and in particular contain a relatively large proportion of fine particles.Moreover, such highly brittle materials When used for development in a copying machine, etc., it is often pulverized or powdered again.
With this method, it is difficult to completely and uniformly disperse solid particles such as colorants into the resin, and depending on the degree of dispersion, it may increase fog, reduce image density, or cause poor color mixing and transparency. Therefore, attention must be paid to dispersion. Furthermore, exposure of the colorant to the fracture surface may cause variations in development characteristics.

On the other hand, in order to overcome the problems of toner produced by these pulverization methods, methods for producing toner using a suspension polymerization method have been proposed in Japanese Patent Publications No. 36-10231, No. 43-10799, and No. 51-14895, etc. . In the suspension polymerization method, a monomer composition consisting of a polymerizable monomer, a colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, and other additives is mixed into a continuous polymer composition containing a dispersion stabilizer. The toner particles are dispersed in a phase, for example, an aqueous phase using a suitable stirrer, and a polymerization reaction is simultaneously carried out to obtain toner particles having a desired particle size. Since this suspension polymerization method does not include a mechanical pulverization step, there are no inconveniences caused during pulverization that occur in pulverization methods.

In recent years, there has been a demand for reducing toner consumption in copying machines, and one way to do this is to improve the coloring power of the toner.One way to improve the coloring power is to increase the colorant content. However, even in this method, the polymerization method is preferable to the pulverization method as a toner manufacturing method from the viewpoint of exposure of the colorant.

However, when the coloring power of toner is improved by increasing the amount of colorant, overhead projector (OIIP)
It has been found that difficulties arise in the transparency of the film. In other words, in the past, the mainstream of old IPs was the transmissive type, but as miniaturization efforts were made, the reflective type became more popular. , in the reflective type, it passes through twice and is projected. For this reason, the transmission type 011
Even if an image had sufficient transparency when using P, sufficient transparency could not be obtained when using a reflective OHP, resulting in a projected image with low brightness. It has arisen.

[IME to be solved by the invention The object of the present invention is to have sufficient coloring power and to
The object of the present invention is to provide a color toner in which an image on a P film has good transparency.

[Means and effects for solving the problems] The color toner of the present invention was developed to achieve the above-mentioned object, and more specifically, it is a toner particle containing a chromatic pigment as a colorant in a dispersed state. , the number average particle diameter of the pigment in the particles is 20 to 300a+μ, and the standard deviation of dispersion is 50mμ.
This is achieved by using a spherical color toner characterized by the following characteristics.

The present invention will be described in detail below.

The spherical shape in the present invention includes not only pearls but also irregular shapes such as eyebrows. In other words, the toner surface has no corners from a macroscopic perspective, and even if there are corners or waves on the microscopic surface, it does not have a spherical shape. Included in

The method for measuring the dispersibility of the colorant in the toner is as follows.

That is, toner particles are internally added to an epoxy resin, cut into a thin film with a thickness of several hundreds, and then the thin film is photographed using a transmission electron microscope.The obtained image (photograph) is used to analyze the film using an image analyzer. Analyze the existing state of pigments (dispersibility, agglomeration, number of particles, etc.). The standard deviation (σ) of dispersion is determined by the following formula from the size and number of particles photographed by an image analyzer.

As a method for producing the spherical toner of the present invention, a suspension polymerization method is preferably used.

Particularly, in order to obtain a toner in which the colorant is highly dispersed as in the present invention, a step of sufficiently dispersing the colorant is essential in the manufacturing process. That is, a coloring agent is added to the polymerizable J# polymer, and a dispersion process is performed using a high-efficiency, high-speed dispersion machine such as a ball mill, Heiline mill (Tokushu Kika Kogyo), or Ebara Milder (Ebara Corporation). A charge control agent, a polymerization initiator, and other additives are further added to the obtained colorant-dispersed monomer, and the monomer system is uniformly melted or dispersed using an ultrasonic disperser, a homogenizer, etc. It is dispersed in the aqueous phase (ie, continuous phase) containing the stabilizer using a conventional stirrer, homomixer, homogenizer, or the like. Preferably the monomer droplets have the desired toner particle size;
In general, the stirring speed and time should be adjusted so that the particles have a size of 30 μm or less, and after that, the stirring should be carried out to the extent that the particles will remain in that state due to the action of the dispersion stabilizer and that sedimentation of the particles will be prevented! i Polymerization degree is 40℃ or higher, generally 5
Polymerization is carried out at a temperature of 0 to 90°C. After the reaction is completed, the generated toner particles are washed, collected by filtration, and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium per 100 parts of monomer.

Polymerizable monomers that can be applied to the toner of the present invention include:
Styrene, 0-methylstyrene, m-methylstyrene,
Styrene and its derivatives such as p-methylstyrene, p-methylstyrene, p-ethylstyrene: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, low octyl methacrylate, methacrylic acid Methacrylic acid esters such as dodecyl, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid isobutyl,
Acrylic acid esters such as propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; acrylonitrile, methacrylonitrile, acrylamide, etc. There are vinyl monomers such as acrylic acid or methacrylic acid conductors.

These ingredients can be used alone or in combination. Among the above-mentioned polymers, it is preferable to use styrene or a styrene derivative alone or in combination with other monomers as a polymerizable monomer from the viewpoint of the development characteristics and durability of the toner.

or,! It is more preferable to polymerize the monomer by adding a polymer or copolymer having a polar group as an additive during polymerization of the 1Lijk body. In the present invention, a polymerizable monomer system to which a polymer, copolymer, or cyclized rubber having a polar group is added during polymerization is suspended in an aqueous phase in which a dispersant having an opposite charge to the polar polymer is dispersed. It is preferable to carry out the polymerization in a cloudy manner, that is, the cationic or anionic polymer, copolymer or cyclized rubber contained in the polymerizable monomer system is dispersed in the aqueous phase. The cationic polymer and the toner particle surface are electrostatically attracted to each other during polymerization, and the dispersant covers the particle surface to prevent coalescence and stabilize the particles. Because it gathers on the surface of the particle, it takes on a kind of shell-like shape, and the resulting particle becomes a pseudo-capsule. A relatively high molecular weight polar polymer, copolymer or cyclized rubber is used to give the toner particles excellent blocking properties and development abrasion resistance, while a relatively low molecular weight internal material improves fixing properties. By performing polymerization to contribute to
Examples of polar polymers (including polar copolymers) and oppositely charged dispersants that can be used in the present invention are exemplified below.

(i) Cationic polymers include nitrogen-containing, 1-mer polymers such as dimethylaminoethyl methacrylate and diethylaminoethyl acrylate, or combinations of styrene, unsaturated carboxylic acid esters, etc., and the nitrogen-containing monomer. There are copolymers. (ii) Anionic polymers include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid, unsaturated dibasic acids, and unsaturated dibasic acids. There are anhydrides and polymers of nitro monomers. Cyclized rubber may be used instead of the polar polymer.

(iii) As the anionic dispersant, Aerosil #
200.1300. There are colloidal silicas such as #380 (manufactured by Nippon Aerosil Co., Ltd.).

(iv) Examples of the cationic dispersant include hydrophilic positively charged silica fine powder such as aluminum oxide and aminoalkyl-modified colloidal silica.

Such a dispersant is preferably used in an amount of 0.2 to 20 parts by weight per 100 parts by weight of the polymerizable monomer. More preferably 0.
3 to 15 times 1 part.

As the chromatic pigment used as a coloring agent in the present invention, generally known pigments can be used, but those without aqueous phase transferability are particularly preferred.

For example, (:, 1. Pigment Blue 15:3 horns//1
5:4 〃〃68 〃 Yellow 17 〃〃12 〃〃13 〃〃14〃 Red 122 // ) J 57:1 etc. are mentioned.

On the other hand, as the charge control substance added as necessary, generally known substances can be used. For example, nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms, metal complex salts of monoazo dyes, metal complex salts of salicylic acid, dialkyl salicylic acid, etc. are used.

Further, in order to improve the a-type property during hot roll fixing, waxes containing hydrocarbon compound rings and generally used as a release agent may be added to the toner.

Hydrocarbon compounds that can be used in the present invention have a melting point of 5
Paraffinic hydrocarbons having a temperature in the range of 5 to 70°C are preferably used. For example, paraffin waxes include products manufactured by Nippon Oil Co., Ltd. and Nippon Silukiwa Co., Ltd., and branched paraffin waxes include microcrystalline wax (manufactured by Nippon Seiro Co., Ltd.) and microwax (manufactured by Nippon Oil Co., Ltd.). The amount of wax added is preferably 1 to 30 parts by weight per 100 parts by weight of the polymer.

As the polymerization initiator, any suitable polymerization initiator such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile,
1.1'-azobis(cyclohexane-1-carbonitrile), 2.2'-azobis-4-methoxy-2,
Azo or diazo polymerization initiators such as 4-dimethylvaleronitrile and other azobisisobutyronitrile (AIBN); benzoyl peroxide, methyl edyl ketone peroxide, isopropyl peroxy carbonate, cumene hydroperoxide, 2 .Peroxide-based polymerization initiators such as 4-dichlorobenzoyl peroxide and lauroyl peroxide may be mentioned. These polymerization initiators are generally about 0.0% by weight of the polymerizable monomer.
5-10% initiator is sufficient.

During polymerization, the following crosslinking agent may be present to produce a crosslinked polymer.

Examples of such crosslinking agents include divinylbenzene,
Divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1.3-butylene glycol dimethacrylate, 1. 6-hexane gelicol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.2
'-bis(4-methacryloxyjethoxyphenyl)propane, 2,2'-bis(4-acryloxyjethoxyphenyl)propane, trimethylolpropane triacrylate, trimethylolpropane triacrylate,
Common crosslinking agents such as tetramethylolmethanetetraacrylate, dibromoneopentylglycol dimethacrylate, and diallyl phthalate can be used as appropriate.

If these crosslinking agents are used in large amounts, the toner becomes difficult to melt, resulting in poor fixing properties. In addition, if the amount of stool is small, properties such as blocking resistance and durability necessary for toner will deteriorate, and during hot roll fixing, some of the toner will not completely adhere to the paper and will stick to the roller surface, causing the next It becomes difficult to prevent the offset phenomenon of transfer to paper. Therefore, the amount of these crosslinking agents used is 0.001 N15% by weight, more preferably 0.001 N15% by weight, based on the total amount of monomers.
It is preferable to use it in an amount of 1-101i.

Further, a fluidity modifier may be added to the toner as necessary. The fluidity modifier may be used by being mixed (externally added) with the toner particles.

Examples of fluidity modifiers include colloidal silica and fatty acid metal salts. Further, fillers such as calcium carbonate and finely powdered silica may be incorporated into the toner in an amount of 0.5 to 20% by weight for the purpose of increasing the toner. Furthermore, in order to prevent toner particles from coagulating with each other and improve fluidity, a fluidity improver such as fine Teflon powder may be added.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Note that all parts in the following formulations are parts by weight.

Example 1 0.5 parts of γ-aminopropyltrimethoxysilane was added to 1200 parts of ion-exchanged water, and further 10 parts of Aerosil 200 (Nippon Aerosil) were added, heated to 70°C, and TK
10,0 using a homomixer M type (Tokushu Kika Kogyo)
Disperse for 15 minutes at 00 rpm, and then add 1/10 NHCj
was added to adjust the system pH to 6.

100 parts of styrene, C.1, Pigment Blue 15:
310 parts were placed in a ball mill and subjected to dispersion treatment for 24 hours. Roughly 83 parts of styrene, 17 parts of 2-ethylhexyl acrylate, 32 parts of paraffin wax (melting point 155''F, Taisei Kosan T-550), and 10 parts of cyclized rubber (C-450 manufactured by Hoechst) were added to the dispersion. In addition, the mixture was heated to 70°C and uniformly dissolved and dispersed using a homogenizer M type (Tokushu Kika Kogyo).Dimethyl 2.2% was added to the obtained monomer system as an initiator. - Add 7 parts of azobisisobutyrate (Wako Pure Chemical Industries, Ltd., V-801) and dissolve it uniformly, then pour it into the dispersion medium system prepared in advance,
Under a nitrogen atmosphere, the monomer composition was granulated by stirring at 70°C for 80 minutes at 6,5OOrp+* using a TK homomixer M type. After that, while stirring with a paddle stirring blade, the temperature was 70°C.
, polymerization occurred in 10 hours.

After the polymerization reaction is completed, the reaction product is cooled and 20% by weight N
a) 70 parts of Otl aqueous solution was added to dissolve the dispersant, and the mixture was filtered, washed with water, and dried to obtain a polymerized toner.

0.5 g of the obtained toner was mixed with epoxy resin (Epoch 81
2) 9.3mi', dodecenylsuccinic anhydride (
DDS^) 4.0raRs methylnadic acid anhydride,
(Metyl nadlcanhydride, MN
^) 8.7a+R, tri(dimethylaminomethyl)phenol (DMP-30) It was uniformly dispersed in a 0.3sj mixture and left at room temperature for 2 days.

The obtained toner-containing epoxy resin was microtomed (8
The sample was cut into several hundred thin sections using Seisangyo ■, MT2-8), and the samples were measured using a transmission electron microscope (JEOL ■).

The images (photographs) obtained here are analyzed using an image analysis machine (LUZEX-
The dispersion state of carbon black in the cross section of the toner was analyzed by SOO, Japan Regulator @).

The dispersion state of the pigment in the toner obtained here was a number average particle diameter of 7511μ and a standard deviation of 20.4iμ.

Furthermore, when the particle size of the toner was measured using a Coulter counter (aperture diameter 100 μm), the volume average particle size was 11.
It had a sharp particle size distribution at 0μ. Furthermore, the triboelectric charge amount of this toner against iron powder (2007300 mesh) by the blow-off method was -15.8 μc/g.

To 100 parts of the obtained toner, 0.8 parts of hydrophobic silica (Talco Co., Ltd., Taranox 500) was mixed, and to 8 parts of the obtained silica externally added toner, 92 parts of acrylic coated ferrite carrier was mixed. Image development was carried out using Canon CLC-1 as a developer. The images obtained were clear and had no fog, and the images on the 011P film were clear and transparent even when projected using a reflective overhead projector.

Example 2 100 parts of styrene, C,1, Pigment Yellow 17
7 parts dispersion liquid using high-speed dispersion machine High Line Mill 11L
-50 type (Tokushu Kika Kogyo), 8000 rpm,
Discharge f! Dispersion treatment was performed at c 3 kg/mln for 20 passes. In addition to 107 parts of the dispersion, 83 parts of styrene, 2
- 17 parts of ethylhexyl acrylate, paraffin, wax (melting point 155°F, Taisei Kosan T-550) 32
Part, styrene-methacrylic acid copolymer (copolymerization ratio 9:
1 moj/moffi, weight average molecular weight 49,000) was added, heated to 70°C, and suspension polymerization was carried out in the same manner as in Example 1.

When the dispersion of the pigment in the obtained toner was measured in the same manner as in Example 1, the dispersion state of the pigment was found to be a number average particle size of 108.
mμ, Keyaki standard deviation was 28.4 mμ.

When the particle size of the toner was measured using a Coulter counter (aperture diameter 100 mμ), the volume average particle size was 11.5.
It had a sharp particle size distribution. Further, the triboelectric charge amount of this toner against iron powder (200/31) O mesh) by the blow-off method was -18.7 μc/g.

100 parts of the obtained toner were mixed with 0.8 parts of hydrophobic peroxide (Talco Co., Ltd., Taranox 500), and 8 parts of the obtained silica externally added toner was mixed with 92 parts of acrylic coated ferrite carrier. Image development was carried out using Canon CLC-1 as a developer.

As in Example 1, the obtained image was clear with no fog and had excellent transparency.

Example 3 100 parts of styrene, C,1, Pigment Red 12
25 parts were dispersed in a ball mill in the same manner as in Example 1, and mixed with 83 parts of styrene, 17 parts of 2-ethylhexyl acrylate, 492 parts of C,1, solvent red, and paraffin wax (melting point below 155, Taisei Kosan T- 550)
32 parts, styrene-methacrylic acid copolymer (copolymerization ratio 9
: 1 moj/mol, 11 weight average molecular weight 4.
90,000) and 3 parts of di-tert-butylsalicylic acid chromium complex were added, and after heating to 70°C, suspension polymerization was carried out in the same manner as in Example 1.

When the dispersion of the pigment in the obtained toner was measured in the same manner as in Example 1, the dispersion state of the pigment was found to be a number average particle size of 11.
5 mμ, standard deviation 34.5a+μ.

Also, when the particle size of the toner was measured with a Coulter counter (aperture diameter 100μ), the volume average diameter was 11.3.
It had a sharp particle size distribution. Furthermore, the triboelectric charge amount of this toner against iron powder (200/300 mesh) by the blow-off method was -111.8 μc/g.

To 100 parts of the obtained toner, 0.8 parts of hydrophobic silica (Talco Co., Ltd., Taranox 500) was mixed, and to 8 parts of the obtained silica externally added toner, 92 parts of acrylic coated ferrite carrier was mixed. , a developer, and image formation was performed using CLC-1 manufactured by Canon. The obtained image is
As in Example 1, the image was clear without fog and had excellent transparency.

Comparative Example 183 parts of styrene, 1 part of 2-ethylhexyl acrylate
7 parts, C, 1, Pigment Blue 15: 310 parts, paraffin wax (melting point 155'F, Taisei Kosan T-55
0) 32 parts, cyclized rubber (manufactured by Hoechst, C-450)
10 parts were mixed, heated to 70° C., and uniformly dissolved and dispersed using a T, K> type homogenizer M type. To the obtained monomer system, 7 parts of dimethyl 2,2-azobisisobutyrate (V-Rot, manufactured by Wako Pure Chemical Industries, Ltd.) was added as an initiator, and after uniformly dissolving, the mixture was prepared in the same manner as in Example 1. Suspension polymerization was carried out to obtain a toner. When the dispersion of the pigment in the obtained toner was measured in the same manner as in Example 1, the number average particle diameter of the pigment was 355! Ilu.

The standard deviation was 63 mμ.

A developer was prepared from this toner in the same manner as in Example 1, and an image was developed using a Canon CL (knee 1).
Images on paper are clear with no fog, and images on 011P film have sufficient transparency when used with a transmissive projector, but when using a reflective projector, the brightness of the projected image changes. It was found that the transparency was poor.

[Effects of the Invention] As described above, when the color toner of the present invention is used, it is possible to obtain clear copied images without fogging, and in particular, it exhibits excellent transparency in 01 (P film) and is suitable for reflective OHPs. .

Claims (1)

[Claims] A color toner containing a chromatic pigment as a colorant in a dispersed state in toner particles, wherein the number average particle diameter of the pigment in the toner particles is 20 to 300 mμ, and the standard deviation of dispersion is 5.
A color toner having a particle size of 0 mμ or less and having spherical toner particles.