JPS63287858A - Photoconductive toner - Google Patents

Abstract

PURPOSE:To obtain the title toner having high photosensitivity and excellent dispersibility and thermal stability by incorporating a specified alpha-substituted stilbene compd. in the title toner as an electric charge transfer substance. CONSTITUTION:The title toner contains an electric charge generating substance 1 and the electric charge transfer substance 2 in particles composed of a thermoplastic resin 3 as a main component. The electric charge transfer substance 2 contains the alpha-substituted stilbene compd. shown by the formula wherein R1 is aryl group, R2 is alkyl or aryl group, etc., R3, R5 and R6 are each hydrogen atom or alkyl group, etc., R4 is arylene group, etc., (n) is 0 or 1. Thus, the title toner having good thermal stability and improved dispersibility and excellent photosensitivity is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to toners, particularly photoconductive toners, for use in electrophotography.

2. Description of the Related Art Electrophotographic image forming methods are widely known. The usual method is to charge the entire surface of the photoreceptor by corona discharge, and then to form an electrostatic latent image by irradiating the photoreceptor with imagewise light. At this time, the exposed portion of the photoreceptor becomes conductive and the charge disappears, and the unexposed portion remains as an electrostatic latent image. When toner of opposite polarity is brought close to this electrostatic latent image, the toner is electrostatically attracted and the latent image is visualized.

In one type of xerography, the image is transferred to plain paper and fixed, and in the electrofax method, it is directly fixed on a photoreceptor. The problem with these methods is that these steps are complicated, making the electrophotographic copying apparatus complicated and expensive. In addition, since the copying system is composed of five independent members, the photoreceptor and the toner powder, that is, the developer, if the performance of one of the two members deteriorates, for example, Therefore, in order to always maintain the desired performance of the photoreceptor and the developer, there were problems such as maintenance including the system becoming difficult.

In recent years, in order to solve these problems, a copying process has been proposed that does not use a photoreceptor but uses a photoconductive toner in which a developer is imparted with photoconductivity.

This method is a method in which the toner itself has the ability to form an electrostatic latent image, and since it does not require a photoreceptor, it simplifies the electrophotographic copying device, reduces manufacturing costs, has the advantage of being easy to clean, and can be done in one shot. Research and development are being actively conducted as a method that enables full-color image formation. (For example, Japanese Patent Publication No. 56-28259, Japanese Patent Publication No. 61-23015)
4 to 61-230158, etc.).

Examples of electrophotography using photoconductive toner include the Sugarman method (US Pat. No. 2,758,939), its variations include a combination method of photoconductive toner and corona discharge, and an electric motive power method.

In order to realize the electrophotographic process described above, the development of photoconductive toner is the key, but such toner must have both functions as a developer and photoconductivity. Due to the difficulty, the photosensitivity in particular is far from a practical level, and it has not yet been put into practical use.

In Japanese Patent Publication No. 56-28259, it has been put to practical use as a photoconductive toner for marking. This toner uses zinc oxide as a photoconductive material with rose bengal as a sensitizer. However, the particle size of the toner is approximately 100 μm.
To a large extent, when considered as a toner for copiers, there is a problem in image quality, and a spray solution containing a solvent is used, making it unsuitable for copiers.

JP-A-61-230154 to JP-A-61-230158 disclose photoconductive toners, but the photoconductive substances are completely different.

Problems to be Solved by the Invention Since photoconductive toners have particularly poor photosensitivity and lack practicality, improvements are desired.

In view of such circumstances, it is an object of the present invention to provide a photoconductive toner with excellent photosensitivity and fixing properties.

Furthermore, the present invention provides a photoconductive toner containing a photoconductive material that is thermally stable, has good dispersibility, and in which the toner powder layer sufficiently retains the required functionality. be.

That is, the present invention provides a photoconductive toner containing a charge generating substance and a charge transporting substance in particles mainly composed of a thermoplastic resin, in which an α-substituted stilbene compound represented by the following general formula CD is used as the charge transporting substance. The present invention relates to a photoconductive toner characterized by containing:

(In the formula, R represents a substituted or unsubstituted aryl group, I represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, R,, R.

and R- represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and k4 represents a substituted or unsubstituted arylene group. Further, kl and R may jointly form a ring, and n is an integer of 0 or 1. ) Examples of the α-substituted stilbene compound represented by the general formula CI) include those disclosed as materials for photoreceptors in JP-A-60-98437. However, no application to photoconductive toners is mentioned.

The present invention provides the α-positional transport layer 6 represented by the general formula CD.
By using this product, it is thermally stable, has good dispersibility, and has excellent electrophotographic properties such as charge retention ability, photosensitivity, and reduced residual potential, and has stable properties even when used repeatedly. It is possible to produce a photoconductive toner that exhibits high performance.

Preferred specific examples of the α-substituted stilbene compound represented by the general formula (1) are shown in Table 1, but the invention is not limited thereto.

9 One example of the structure of the photoconductive toner of the present invention is schematically shown in FIGS. 1 and 2.

FIG. 1 shows a dispersed photoconductive toner (hereinafter referred to as "dispersed photoconductive toner") in which a charge generating substance (1) is dispersed together with an α-substituted stilbene compound (0) in a thermoplastic resin (3). shows.

Figure 2 shows a coated photoconductor in which a thermoplastic resin (0) in which a charge-generating substance (1) is dispersed is coated around a nuclear core substance (4) containing an α-substituted stilbene compound (2). photoconductive toner (hereinafter referred to as "coated photoconductive toner"). A coated photoconductive toner can improve light transmittance, and even when a single toner layer is formed into multiple layers, it is very advantageous in terms of photosensitivity.

Dispersed photoconductive toner can be produced by applying a known method. For example, a charge-generating substance is dispersed in a solution containing an α-substituted stilbene compound and a thermoplastic resin solution, and a spray-drying method is used to produce the dispersion type photoconductive toner. You can also create
It may be produced by a thermal kneading method without using a solvent, and the particle size is adjusted to 1 to 30 μm, preferably 5 to 25 μm, more preferably 8 to 20 μm, without any particular limitation.

If the particle diameter is smaller than 1 μm, the fluidity and development characteristics of the toner will be poor, and the photosensitivity will be significantly lowered. If it is thicker than 30 μm, the final image, especially the resolution, will be poor. At this time, the α-substituted stilbene compound is 5-
The content is 90w%, preferably 10 to 50w%. If it is less than 5 wt%, the photosensitivity will be insufficient and the residual potential will be high.

If it exceeds 90W%, the binding property with the resin will be poor and granulation will be difficult. Examples of the charge generating substance include inorganic substances such as amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, mercury sulfide, lead oxide, lead sulfide, and amorphous silicon;
Furthermore, azo dyes such as monoazo, disazo, and trisazo dyes, perylene dyes, anthraquinone dyes, polycyclic quinone dyes, indigoid dyes, phthalocyanine nitrone dyes, benzoquinone and naphthoquinone dyes, naphthalimide dyes, and perinone. Examples include organic substances such as quinacridone dyes and quinacridone dyes. These may be used alone or in combination of two or more. Special (disazo, trisazo, perylene series,
It is preferable to use polycyclic quinone-based and phthalocyanine-based dyes.

The charge generating substance has a power of 1 to 90 W[%, preferably 5 to 50
W[%]. If it is less than 1 wL%, the photosensitivity and coloring power will be insufficient. If it exceeds 90W%, the binding property with the resin will be poor and granulation will be difficult. When shredded toner forms multiple layers, light cannot reach the layers below, causing problems such as poor photosensitivity and increased residual potential. Note that a conductive substance may be added as necessary to suppress the increase in residual potential. If the amount of conductive material is large, problems such as increased dark decay and poor charging properties will occur, so it is desirable that the amount is 20 W% or less.

Thermoplastic resins include polyethylene resin, acrylic resin, methacrylic resin, polyester resin, polyamide resin, polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyvinyl chloride,
Ethylene-vinyl acetate copolymer, styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-butadiene copolymer, styrene-vinylidene chloride copolymer, styrene-vinyl chloride copolymer, styrene -vinylidene fluoride copolymer, styrene-acrylonitrile copolymer, epoxy resin, modified rosin,
Polyethylene wax, polycarbonate resin, etc. can be used alone or in combination.

Further, when the photoconductive toner of the present invention is used particularly as a toner for pressure fixing, the thermoplastic resin may include polyolefins (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, poly(47)ethylene, etc.),
Epoxy resin, polyester resin (acid value 10 or less), styrene-butadiene copolymer (monomer ratio 5-30:9)
5-70), olefin copolymers (ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers,
Ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, (ionomer resin), polyvinylpyrrolidone, methyl vinyl ether-maleic anhydride copolymer , maleic acid-modified phenol resin, phenol-modified terpene resin, etc. can also be used.

In the case of a coated photoconductive toner, it can be obtained by further forming a layer containing a charge generating substance on the core material. As the binder resin, the same thermoplastic resin as described above can be used. For example, a method of coating a layer containing a charge-generating substance on a nuclear material by a spray drying method, or a thermoplastic resin. Methods such as using resin monomers to create a multilayered polymer by methods such as emulsion polymerization or suspension polymerization can be used.

The thickness of the coating layer is in the range of 0.1 to 10 μm, preferably 0.1 to 2 μm, and depending on the type and amount of each composition, in practice, the chargeability and photoconductivity of the photoconductive toner are determined. , appropriate conditions are selected depending on characteristics such as print density when an image is formed.

The amount of the charge generating substance contained in the coating layer is 5 to 100 wt%, preferably 20 to 80 W-%, more preferably 30 to 60 W-%, based on the total amount of the coating layer.
%. If it is less than 5 wL%, the photosensitivity will generally be poor, and the print density as a final image may be insufficient.

The particle size of the core material is closely related to the particle size of the final photoconductive toner, and therefore affects the final image quality, especially the resolution, and is usually 1 to 30 μm, preferably 5 to 20 μm.
It belongs to m. If it is smaller than 1 μm, the fluidity, development characteristics, and photosensitivity of the toner will be poor;
If it is thicker than μm, the final image quality, special resolution, and development characteristics will be poor.

Note that, although it is desirable that the nuclear core material is spherical, the shape is not limited.

The thermoplastic resin used in the core material can be the same as the thermoplastic resin described above, and in addition to the thermoplastic resin or the thermoplastic resin, α according to the present invention can be used.
-Pelletization of various components including a substituted stilbene compound by a heat kneading-pulverization method may be used. Alternatively, a method of emulsion polymerization or suspension polymerization of a mixture of a thermoplastic binder resin monomer or prepolymer, a monosubstituted stilbene compound, and other various components, etc.1. It may also be obtained by subsequent granulation using a spray drying method.

The amount of the α-substituted stilbene compound to be added is preferably such that it does not precipitate when the core particles are prepared together with the thermoplastic resin, and it also depends on the type of resin and α-substituted stilbene compound, or whether it is added alone or in combination. Although it varies depending on the amount of resin, it is about 0.1 to 95 wt%, preferably 30 to 80 W[%, more preferably 40 to
60W [% added. 0. IW[If it is less than 95wt%, the carrier transport ability in the nuclear core material will be poor.
If the amount is larger than this, the α-substituted stilbene compound usually precipitates in the resin, making granulation difficult. Of course, one or more types of α-substituted stilbene compounds may be used as the charge transporting substance, or substances other than the α-substituted stilbene compounds may be used in combination.

Furthermore, the coating layer containing the charge generating substance may contain an α-substituted stilbene compound to increase photosensitivity (FIG. 3). In this case as well, the α-substituted stilbene compound may be the same as the α-substituted stilbene compound contained in the core particle, or a different α-substituted stilbene compound may be used. Of course, it may be added alone or in combination, and α-
It may be used in conjunction with charge transport materials other than substituted sterpene compounds.

When an α-substituted stilbene compound is present in the coating layer, the amount of the α-substituted stilbene compound to be contained is 0 to 80 W[%, preferably 0.1 to 5 QwL%, more preferably 1 ~30W [
%. If the amount is more than 80W%, the α-substituted stilbene compound may precipitate, making it difficult to form a coating layer.

By including an α-substituted stilbene compound in the coating layer, not only does the movement of photogenerated carriers in the coating layer become easy, but also the movement of carriers between the nuclear core substance and the coating layer becomes easy. An improvement in photosensitivity is achieved.

A toner showing another aspect of the present invention includes a nuclear core material (
4) contains an α-substituted stilbene compound (2) and a charge generating substance (1), and the coating layer contains a charge generating substance (1).
) containing photoconductive toner (Figure 4), nuclear core material (4)
and a photoconductive toner containing both a charge generating substance (1) and an α-substituted stilbene compound (2) in both coating layers (Fig. 5), a charge generating substance (1) in the core material (4) , α-substituted stilbene compound (
2) (Figure 6), a charge generating substance (1) in the nuclear core material (4), and a charge generating substance (1) in the coating layer.
and a toner containing α-substituted stilbene compound (2) (
(Fig. 7), nuclear body core substance (4) (this α-substituted stilbene compound (2) and charge generating substance (1), toner containing charge generating substance (1) in the coating layer (Fig. 8), or nucleus The core substance (4) contains nothing, and the coating layer contains the charge generating substance (1) and the α-substituted stilbene compound (
2) (FIG. 9) and the like.

In order to take advantage of the coating type photoconductive toner, which can obtain sufficient light transmittance and good photosensitivity, it is necessary to use a toner containing a core material containing an α-substituted stilbene compound and a charge generating material. Photoconductive toners formed from coating layers, ie, photoconductive toners of the embodiments shown in FIGS. 2-5, are preferred.

Colorants include known pigments or dyes, such as carbon black, nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, and malachite green. It may be oxalate, lamp black, oil black, azo oil black, rose bengal, or a mixture thereof.

In addition, as a sensitizer, chloranil, tetracyanoethylene, 2,4,7-)Lietro 9-alolenon,
5. Electron-withdrawing sensitizers such as -15=-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride, 3,5-dinitrobenzoic acid, methyl violet, rhodamine B1 cyanine dye, pyrylium salt, thiapyrylium salt, etc. are used. It is also possible to do so.

In the photoconductive toner of the present invention, known additives may be used as appropriate within the range that does not impede the objects and effects of the present invention. As such additives, wax etc. can be added to improve fixing properties, and conductive substances such as fine metal oxide powder can be added to further improve photoconductivity.
In particular, it is possible to reduce the residual potential. Furthermore, in order to improve the properties as a toner, magnetic powder, colorant, charge control agent, fluidizing agent, etc. can be added as appropriate.

Particularly in the case of a coated photoconductive toner, a conductive substance such as wax or fine metal oxide powder may be added to the core material to improve fixing properties and conductivity. A charge control agent, a fluidizing agent, wax, or the like can be added to the coating layer to improve charging properties, fluidity, and fixing properties.

Further, when used as a toner containing a magnetic substance, magnetite (triiron tetroxide) is most preferable because it is desirable to obtain the toner. Typical magnetic or oxidizable materials include cobalt, iron, nickel, metals such as aluminum, cobalt, copper, iron, lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium. Alloys and mixtures of metals such as , manganese, selenium, titanium, tungsten, vanadium: metals including metal oxides such as aluminum oxide, iron oxide, copper oxide, nickel oxide, zinc oxide, titanium oxide, and magnesium oxide Compounds: refractory nitrides such as vanadium nitride and chromium nitride; carbides such as tungsten carbide and silica carbide; ferrite and mixtures thereof, etc. may be used.

These ferromagnetic materials preferably have an average particle size of about 0.1 to 1 μ^, and are contained in the toner in an amount of about 50 to 300 parts by weight per 100 parts by weight of the resin component, particularly preferably about 50 to 300 parts by weight of the resin component. 90-20 per 100 parts by weight
It is 0 parts by weight.

When the purpose is a color magnetic toner, r-Fe, O
, brown magnetic material or magnetic powder whose color is hidden by surface treatment is used.

Further, the toner of the present invention can be used together with a fluidizing agent if necessary, and the fluidizing agent is preferably a fine powder of hydrophobic silica, titanium oxide, aluminum oxide, etc., and the amount used is determined according to the toner. 01~lWL% against
is preferred.

The photoconductive toner of the present invention can be used in a copying machine that does not have a photoreceptor. Therefore, the simplification of copying machines,
A reduction in manufacturing costs can be achieved. The photoconductive toner of the present invention can also be used in conventional copying machines.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these examples.

Example 1 Styrene acrylic copolymer resin (58M73, manufactured by Sanyo Chemical Industries, Ltd.) 100 parts by weight Disazo compound (chlorodiane blue, the following structural formula (A)) (a) 3
0 parts by weight α-substituted stilbene compound (2) represented by the following structural formula
30 parts by weight Viscoel 550P (manufactured by Sanyo Chemical Industries, Ltd.) 5 parts by weight After thoroughly mixing the above materials using a ball mill with 5 trowels,
The mixture was kneaded on a triple roll heated to 0°C.

After cooling, the mixed material was roughly pulverized in a feather mill, then pulverized in a pulverizer using a jet stream, and further classified by air to obtain a photoconductive toner (■) having an average particle size of 13 μm.

Example 1 of "Hide" - Styrene-acrylic copolymer resin (softening point 135°C, glass transition point 58°C) 100 parts by weight Disazo compound Chlorodiane blue used in Example 1 (~30 parts by weight α represented by the following structural formula) -substituted stilbene compound (11
) 30 parts by weight of Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) 5 parts by weight were added in the same manner as in Example 1 to obtain a photoconductive toner (■) having an average particle size of 12 μm.

Example 3 a) Production of core particles Styrene 70 parts by weight (polymerization initiator) α-substituted stilbene compound (1) represented by the following structural formula
To the uniform dispersion having the above composition, a dispersion medium containing 400 parts by weight of a 98w1% methyl cellulose solution and 01 parts by weight of sodium lauryl sulfate was added, followed by homomixing at 5000 rpm for 10 minutes at room temperature. This mixture was degassed and replaced with nitrogen, then heated to 70°C, and polymerized for 6 hours while stirring normally. Add this solution to 2 parts distilled water! After repeating the operation of placing the particles in a container and performing decantation three times, the particles were separated using a centrifugal separator and dried with soot to obtain microparticles with an average particle size of 10 μm.

b) Production of photoconductive toner Thermoplastic resin styrene 70 parts n-butyl methacrylate 20 parts diethylaminomethacrylate 10 parts by weight Copolymer (softening point 132°C, glass transition point 58°C) 10 parts by weight The following structural formula An α-substituted stilbene compound having a core particle composition of 30 parts by weight of a disazo compound represented by "
(1) After uniformly dispersing and stirring 10 parts by weight or more of the substance in toluene by high-shear stirring, the nucleus material produced in step (a) was added, and the surface was spray-dried using a spray drying method. As a result of coach incubation, the average particle size was 11 μm.

A photoconductive toner (■) with a surface coating layer of 10 μm was obtained.

After uniformly scattering the photoconductive toners ■ to ■ obtained in Evaluation Examples 1 to 3 on a brass substrate to form a thin toner layer, -1
A single layer of toner was uniformly charged by corona charging at -5 KV, and then imagewise exposure was performed to form an electrostatic latent image on the single layer of toner.Next, plain paper was brought into close contact with the toner layer, and the above-mentioned The toner in the latent image area is transferred onto plain paper by corona charging with a polarity opposite to that of the charging polarity, and then heated and fixed to form toner ■, @yoshi blue-purple, and toner ■.
A clearer reddish-purple image was obtained.

Effects of the Invention According to the present invention, a photoconductive toner having good photosensitivity and excellent dispersibility and thermal stability can be obtained.

[Brief explanation of the drawing]

1 to 9 are schematic cross-sectional views showing one embodiment of the photoconductive toner of the present invention. (1)...Charge generating substance (2)...α-substituted stilbene compound (3)...Thermoplastic resin (4)...Nuclear core material Patent applicant Minolta Camera Co., Ltd. Figure 7 Figure 3

Claims (1)

[Claims] 1. In a photoconductive toner containing a charge-generating substance and a charge-transporting substance in particles mainly composed of a thermoplastic resin, α- represented by the following general formula [I] is used as the charge-transporting substance. Photoconductive toner characterized by containing a substituted stilbene compound; ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (In the formula, R_1 represents a substituted or unsubstituted aryl group, and R_2 represents a substituted or unsubstituted aryl group. Represents a substituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and R_3, R_5, and R_
6 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and R_4 represents a substituted or unsubstituted arylene group. Further, R_1 and R_2 may jointly form a ring. n is an integer of 0 or 1. )