JPS61248058A - Toner - Google Patents

Abstract

PURPOSE:To prevent pulverous particles to be incorporated into a toner from staining the surface of a photosensitive body and the surface of a toner carrying body by subjecting preliminarily the pulverous particles to a specific treatment. CONSTITUTION:The toner consists of a binder resin and the pulverous particles. Said pulverous particles are preliminarily treated with a material of which the critical surface tension is rc<=30dyne/cm. The material having rc<=30dyne/cm critical surface tension is exemplified by a polyvinyl fluoride, etc. The polymer having 1,000-500,000 number average mol.wt. is preferable in terms of moisture resistance, etc. in the case of the fluoropolymer. The pulverous particles has more preferably 1.0-100m<2>/g specific surface area BET. The content of the treating material in the treated pulverous particles is more particularly preferably 0.1-15wt% by the weight of the pulverous particles.

Description

Detailed Description of the Invention [Technical Field to which the Invention Pertains] The present invention relates to a method for developing an electrostatic latent image or a magnetic latent image formed by electrophotography, electrostatic recording, electrostatic printing, or magnetic printing. Regarding the toner used for

[Description of prior art]

Image forming methods conventionally known as electrophotography, electrostatic printing, electrostatic recording, or magnetic printing involve the process of visualizing the formed image using colored fine powder called toner. Contains. For example, electrophotography is described in U.S. Pat.
As described in Japanese Patent No. 748, various methods are known, but in general, an electrostatic charge image is formed on the surface of a photoreceptor using a photoconductive substance by various methods, and then the electrostatic charge image is The toner image is developed with toner, the toner image is transferred to a transfer material such as paper as required, and then fixed by heating, pressure, etc. to obtain a copy.

The electrostatic printing method is a method of guiding and fixing charged powder toner onto a recording material using an electric field to print.

Electrostatic recording is a method in which a charge is applied to an image on a dielectric layer, and charged toner powder is attached to and fixed on the image. Similarly, magnetic printing is a method in which a magnetic latent image is formed on a recording material. This is then developed with toner powder containing a magnetic material, transferred to a transfer material, and fixed.

Various developing methods are known in which such electrical and magnetic latent images are visualized using toner, but the toner applicable to these developing methods is as follows.

Conventionally, fine powders have been used in which fine particles of coloring agents such as dyes and pigments are dispersed in a binder resin made of natural or synthetic resin. For example, using folystyrene as the binder resin and dispersing a coloring agent in it, the
In order to obtain a magnetic toner in which particles pulverized to a certain degree are used as a toner, a toner containing magnetic particles such as magnetite is used. There are two-component developers that use the toner mixed with carrier particles such as glass peas and iron powder, and one-component developers that use only toner without using carrier particles. These toners are
Various VJ buried and chemical properties are required, such as triboelectrification, fluidity, and impact resistance. however,
There are very few conventional toners that satisfy all of these characteristics, and many of the known toners have several problems as shown below. That is, the triboelectric properties of many toners are adversely affected by changes in environmental humidity.

or.

For many toners, the density of the resulting image changes due to collisions between toner particles and carrier particles due to repeated development through continuous use, and mutual deterioration of the toner, carrier particles, and photosensitive plate due to contact between these particles and the surface of the photosensitive plate. or the background density increases, reducing the quality of the copy. Furthermore, with many types of toner, if you try to increase the density of the copied image by increasing the amount of toner that adheres to the surface of the photosensitive plate that has the latent image,
Normally, the background intensity increases, causing the so-called Capri phenomenon. Many of the known toners have one or more of the above defects.

At present, there is a constant demand for improvements in toner.

In addition, recently, the purposes for which the above-mentioned electrophotography is used are diverse, and there is a desire for a compact and inexpensive color copying machine that can produce images in desired colors as needed, and toner has been developed for this purpose. is an urgent need. In this sense, color toners need not only to have excellent physical and chemical properties that overcome the above-mentioned defects, but also to have good hue.

Further, in addition to the binder resin and the colorant, auxiliary agents such as a charge control agent may be added to the toner as necessary.

However, conventional dyes, pigments, and substances known as charge control agents, when used as toner materials, satisfy all of the basic characteristics such as hue, charge control, environmental dependence, heat resistance, light resistance, and fixability. However, there were some problems.

For example, when dyes are used as colorants.

Although it is easy to obtain clear hues, it has the following problems.

It generally has poor heat resistance and light resistance, and tends to discolor or fade due to damage caused by heat kneading during toner production, or when the resulting image is exposed to artificial light or left outdoors for long periods of time. is strong. Alternatively, when the developer is stored at a relatively high temperature, the toner tends to aggregate.

For example, when pigments are used as colorants, they generally have better heat resistance and light resistance than dyes, and toner aggregation does not tend to occur even when stored at high temperatures. However, many pigments have problems with their dispersibility in binder resins. In other words, this is not a major problem when using a binder resin made of a polymer with a relatively low molecular weight, but pigment dispersion may be difficult when using a binder resin with a relatively high molecular weight or a crosslinked type. The problem arises that it is not done enough.

For example, phthalocyanine pigments, which are used in an extremely wide range of fields as blue to green pigments, are a typical example of the pigments that tend to cause poor dispersion as described above when used in electrophotographic toners.

As a result, the following characteristic problems arise.

In other words, many pigments have poor coloring power to toner,
Therefore, it is necessary to add a large amount of pigment, resulting in poor fixing properties.

In addition, due to variations in the distribution of pigment within toner particles (some toner particles containing a large number of pigment particles and some toner particles containing no pigment particles at all), the chargeability of the toner itself may be affected. Unstable, long-term repeated use,
Alternatively, environmental changes (changes in temperature and humidity) may cause negative effects such as a decrease in image density and an increase in soil blur.

Furthermore, since there are bare pigment particles that are not immersed into the toner particles, these particles may not be absorbed into the photoreceptor surface or the sleeve.
Contaminates toner carriers such as carriers, causing filming,
This may cause undesirable phenomena such as image blurring, poor cleaning, soil blurring, and a decrease in image density.

As described above, the current situation is that even if dyes or pigments are directly incorporated into toners as colorants, only toners with certain problems can be obtained.

[Purpose of the invention]

The present invention has been made in view of the above points.

That is, the main object of the present invention is to prevent the fine particles from contaminating the surface of the photoreceptor or toner carrier.

The purpose of the present invention is to provide a toner having excellent electrophotographic properties.

Another object of the present invention is to provide a toner that faithfully develops, transfers, and fixes the latent image, that is, there is no fogging phenomenon, toner scattering around the latent image, poor fixing, offset, etc., and the image density is high. The purpose of the present invention is to provide a toner with excellent reproducibility in halftone areas.

Another object of the present invention is to provide a toner that maintains its initial good characteristics even after long-term use and environmental changes.

Yet another object of the present invention is to reduce the amount of triboelectric charge of toner in a method in which toner is triboelectrified between toner particles or between toner and carrier or on a toner carrier in the case of one-component development by any frictional means. The object of the present invention is to provide a developer that is stable, has a uniform triboelectric charge amount distribution, and can be controlled to a charge amount suitable for the developing system used. However, all the frictional means mentioned here include the frictional charging of the toner by the toner carrier tab developing sleeve, or the frictional charging by other frictional members.

[Structure of the invention]

In order to achieve the above-mentioned object, the present inventor continued intensive research and found that the above-mentioned object could be achieved by subjecting the fine powder contained in the toner to a specific treatment in advance.

Specifically, the toner of the present invention is characterized in that it comprises at least a binder resin and fine particles, and the fine particles are pretreated with a substance having a critical surface tension (γC) of rc≦50 dyne/cm. That is.

Critical surface tension cuff referred to here; , cos θ=1', and the surface tension value obtained by removing the point is called the critical surface tension of the target substance.

Examples of the substance having the critical surface tension rc≦30 dyne/cnI include fluorinated vinyl resins such as polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polytetrafluoroethylene, and polyhexafluoropropylene; Fluorinated epoxy resins, fluorinated tetraurethanes, organic acids with fluorinated carbon groups, etc.

Examples include fluorine carbide surfactants. In the case of fluorine-based polymers, the number average minute weight is 1,000 to soo, oo
o is preferable in terms of moisture resistance and the like.

Further, as the fine particles used in the present invention, conventionally known pigments 1 such as anthraquinone type, quinacridone type,
Various organic pigments such as phthalocyanine, perylene, perinone, and azo, as well as titanium oxide, iron oxide, yellow lead, ultramarine,
Various inorganic pigments such as navy blue, various metal oxides, metal chlorides, mixtures thereof, metal compounds such as metal complexes, etc. can be used. Then, the fine particles were obtained by the nitrogen adsorption method.
ET specific surface area is 0.1 m2/l ~ 300 m2/?
, preferably 10 m2/1 to 100 m2/f.

A specific method for producing the fine particles used in the present invention is, for example, by dissolving and dispersing the above-mentioned treatment substance in a solvent such as toluene, xylene, methyl ethyl ketone, etc., and mixing the above-mentioned fine particles into this dispersion.

Examples include methods such as a spray dryer method, a fluidized pellet method, etc., in which fine particles are coated with the treated substance, dried, granulated, sieved, and the passed through particles are used as treated fine particles.

The content of the treatment substance in the fine particles treated in this way is 0.01 to 50% by weight based on the amount of fine particles.
Preferably 0.05 to 30% by weight, especially 0.1
~15 weight percent is good.

All commonly used methods can be used for producing the toner used in the present invention.

Specifically, the binder resin and the fine particles treated with the above-mentioned treatment substance are melted together, cooled, pulverized, and classified; melt-kneaded, dispersed in liquid, and granulated; melted and mixed, and gas Spraying into the inside, granulation method, or the method of forming the binder resin
For example, the fine particles may be dispersed in advance and then polymerized and granulated.

The binder resin used in the present invention is % polyp-/lorstyrene 1. +? Homopolymers of styrene and its substituted products such as ribinyltoluene; styrene-p-/colstyrene copolymers. Styrene-propylene copolymer, styrene-
Vinyl toluene copolymer, styrene-vinylnaphthalene copolymer, styrene methyl acrylate copolymer.

Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl lylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-alpha chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer (combined), styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, Styrenic copolymers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; polymethyl methacrylate ,
#? Liptyl methacrylate.

Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, Aromatic petroleum resins, chlorinated paraffins, paraffin waxes, etc. can be used alone or in combination.

The effect of the present invention is that the melt flora index value is 0.
．． 1 to 2 (1/10 minutes (test conditions: load 10Kf, 12
A favorable effect was shown when using a binder resin at a temperature of about 5°C. The melt flora index here is based on the Japanese Industrial Standards flow test method for thermoplastics, Tl5K.
Measurement was carried out by manual cutting and method 9 using the apparatus described in 7210.

The binder resin for which the present invention is particularly effective has a weight average molecular weight (M
These are vinyl polymers, polyesters, and epoxy resins synthesized from vinyl monomers having a ratio Mw/Mn of w) and number average molecular weight (Mn) of 4 or more, particularly 10 or more.

Here, the above Mw/Mn value is the gel permeation
Calculated from values measured by chromatography.

The measurement conditions are as follows: Tetrahydrofuran is flowed as a solvent at a flow rate of 1 minute per minute at a temperature of 25° C., and a sample solution of 7 runs of tetrahydro at a sample concentration of 8 mg/− is injected at 0.5 percent. In addition.

As a column, in order to accurately measure the molecular weight range of 103 to 2X10', it is recommended to combine a plurality of commercially available polystyrene cell columns; for example, μ-styrag θ1500%105.104. 105
A combination of 5hoaex A-802 manufactured by Showa Denko,
The combination of 803°, 804.805 is good. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithm value of the calibration fl line prepared using several types of monodispersed polystyrene standard samples and the count number. As a standard folystyrene sample for creating a calibration curve, for example, Pr
essure Chemical Co.

or manufactured by Toyo Tsudani Gyo Co., Ltd. with a molecular weight of 6X102゜2
, lX105.4X105%t75X104%5. lX
104. tlX105.3.9×105.8.6X1
It is appropriate to use at least 10 standard polystyrene samples of 05.2 x 10' and 4.48 x 106. Also.

An R-type (refractive index) detector is used as a detector.

Furthermore, in order to use the toner of the present invention as a magnetic toner, it may contain magnetic powder. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used.
Examples include powders of ferromagnetic metals such as iron, cobalt, and nickel, and alloys and compounds such as magnetite and γ-acid iron oxide rougherite. The content of this magnetic powder is preferably 10 to 70% by weight based on the weight of the toner.

The above toner composition is used as a microcapsule toner.
It is also possible to carry it on the wall material, the core material, or both.

The toner of the present invention may be mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite powder, etc., if necessary, and used as a developer for electrical latent images. The developer of the present invention can be applied to various development methods. For example, magnetic brush development method, cascade development method, U.S. Pat.
A method using a conductive magnetic toner described in No. 909.258, a method using a high resistance magnetic toner described in JP-A-53-31136, and JP-A-54-42.
No. 141, No. 55-18656, No. 54-4
Examples include the method described in Japanese Patent No. 3027, a fur brush development method, a powder cloud method, an impression development method, and the like.

Further, when the developer is held in a developer carrier such as a sleeve, it is possible to use magnetic force, Coulomb force, electrostatic force, image force, mechanical force, etc. Further, as the transfer method used in the present invention, conventionally known methods such as an electrostatic transfer method, a bias roll method, a pressure transfer method, and a magnetic transfer method are used. Furthermore, as a method for cleaning the remaining toner on the photoreceptor, conventionally well-known blade cleaning methods, fur brush cleaning methods, magnetic brush cleaning methods, etc. are used, but the blade cleaning method is particularly suitable for the toner of the invention. ing. Also.

Immediately before the cleaning process, a static elimination process or the like may be provided as necessary to facilitate toner cleaning. The effects of the present invention on IJ-ning properties were particularly favorable for OPC photoconductors (organic photoconductors) and amorphous silicon photoconductors.

〔Example〕

Hereinafter, the present invention will be explained in detail using Examples, but the present invention is not limited to these Examples in any way. Note that all parts in the examples are parts by weight.

Example 1 Copper-phthalocyanine pigment (C Pigment blue)
e15) 10 parts were dispersed in an emulsion of 150 parts of polytetrafluoroethylene (γc = 18.5 dyne/an) and spray-dried using a spray drying device to form fine particles.

The mixture of the above formulation was heated and kneaded at 150° C. for 15 minutes in a roll mill, cooled, crushed in a hammer mill, and then finely pulverized in an air jet type pulverizer. Further, air classification was carried out to select 5 to 25μ, and 1% by weight of colloidal silica was added to prepare a toner.

Next, when copies were made using the toner using a PC-20 copier (Canon's PC-20 is a copier that uses an OPC photoreceptor and employs a blade cleaning method), the result was a clear blue color with no capri. Image obtained. Furthermore, even after making 3000 copies in a row, no problem of poor cleaning or filming occurred.

Example 2 10 parts of black iron oxide (tre5o4) to 200 parts of vinylidene fluoride (γc = 25. Ody
Black iron oxide was obtained by dispersing it in an emulsion of ne/m 2 ) and treating it in the same manner as in Example 1.

A toner was obtained in the same manner as in Example 1 except that the mixture of the above formulation was used.

Next, using the toner, the NP-1502 copying machine (manufactured by Canon. NP-150z is a copying machine that uses an OPG photoreceptor and employs a blade cleaning method) was used to incubate the toner at 35°C with a humidity of 90% and at 10°C. 20,000 copies were made in each environment with a humidity of 5% RH.
There were no occurrences of poor cleaning, filming, or development flow.

Example 3 10 parts of γ-F'e 20 and 2 parts of polytetrafluoroethylene
00 parts (γc = 22.5 dyne/cnt)
The mixture was dispersed in Z-7/l/l/ml and treated in the same manner as in Example 1.

A toner was obtained in the same manner as in Example 1 except that the mixture of the above formulation was used.

The toner was used in an NP-7550 copying machine (manufactured by Canon).

NP-7550 is a copying machine that uses an amorphous silicon drum and employs blade cleaning. ) under an environment of 10°C and 5% humidity for 600. OO0
No IJ-Jung defects or filming occurred during copying.

Example 4 In Example 1, another copper-phthalocyanine (c,
igment Green 7) The same procedure as in Example 1 was carried out except that the number of copies was 15, and no cleaning defects or filming occurred even after 3,000 copies were made.

Example 5 C1 pigment instead of C0 pigment blue15
Good results were obtained when the same procedure as in Example 1 was carried out except that a red pigment having a red pigment of 1 gment Rθd144 was used.

[Comparative Example 1] In Example 1, C1 pigment blue 1
When Example 1 was carried out in the same manner as in Example 1 except that Example 5 was used as is without any treatment, a significant cleaning failure occurred after 1,300 copies were made, resulting in a state that could not be put to practical use.

[Comparative Example 2] The same procedure as in Example 3 was performed except that γ-Fe2O3 was used as it was without being treated.
After copying ,000 copies, a significant cleaning problem occurred.
Many scars were observed on the drum.

[Summary of effects of the invention]

In the toner of the present invention, as described above, fine particles mainly containing one colorant have a critical surface tension of γC≦3°dyne10++.
Since the fine particles are treated with a substance, the adhesion of the fine particles to the photoreceptor surface is improved, and therefore the toner can be cleaned easily from the drum surface, and the triboelectric charging properties of the toner itself are stable. , and the distribution of the amount of triboelectric charge is uniform, and the amount of charge can be controlled to be suitable for the developing system used, and the image density will not decrease even with repeated use over a long period of time or due to environmental changes, and there will be no increase in ground blur. Development and transfer that is faithful to the latent image without any negative effects, such as toner scattering around the latent image, poor fixing, filming, offset, image deletion, poor cleaning, or decrease in image density. and fixing.

Claims (1)

[Claims] (1) Consisting of at least a binder resin and fine particles, the fine particles have a critical surface tension (γc) of γc≦30dyne/c.
1. A toner characterized in that it has been previously treated with a substance.