JPS63148269A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body superior in printing resistance, potential stability, memory characteristics, and residual potential resistance and comparatively easy in manufacture by incorporating a specified none metal phthalocyanine in a photosensitive layer and further, a carrier transfer material in a photosensitive layer. CONSTITUTION:The photosensitive layer contains the none metal phthalocyanine having principal peaks of Bragg angles 2theta to the CuK alpha characteristic X-ray (1.541Angstrom ) of 7.5+ or -0.2 deg., 9.1+ or -0.2 deg., 16.7+ or -0.2 deg., 17.3+ or -0.2 deg., and 22.3+ or -0.2 deg., and further, the carrier transfer material. The carrier generating material of said none metal phthalocyanine having such peaks and the carrier transfer material are both contained in the photosensitive layer, and the single layer type photosensitive body to be used especially for a positively chargeable type is obtained, thus permitting potential stability during repeated uses to be improved, memory phenomena to be reduced, residual potential to be lowered and stabilized, the crystals of the phthalocyanine themselves to be stable, and its manufacture to be easy.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a photoreceptor, particularly an electrophotographic photoreceptor.

BACKGROUND OF THE INVENTION Conventionally, electrophotographic photoreceptors sensitive to visible light have been widely used in copying machines, printers, and the like.

As such electrophotographic photoreceptors, inorganic photoreceptors provided with a photosensitive layer mainly composed of an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide are widely used. However, such inorganic photoreceptors do not necessarily satisfy the characteristics such as photosensitivity, thermal stability, moisture resistance, and durability required of electrophotographic photoreceptors for copying machines and the like. For example, since selenium crystallizes due to heat or fingerprint stains when touched, the above-mentioned characteristics as an electrophotographic photoreceptor tend to deteriorate. Further, electrophotographic photoreceptors using cadmium sulfide have poor humidity resistance and durability, and electrophotographic photoreceptors using zinc oxide have problems in durability. Also, selenium,
Electrophotographic photoreceptors made of cadmium sulfide also have the drawback of being severely restricted in manufacturing and handling.

In order to improve these problems with inorganic photoconductive materials, attempts have been made to use various organic photoconductive materials in the photosensitive layer of electrophotographic photoreceptors, and active research and development has been carried out in recent years. ing. For example, Japanese Patent Publication No. 50-10496 G
This document describes an organic photoreceptor having a photosensitive layer containing a CT complex (charge transfer complex) of poly-N-vinylcarbazole and 2,4,7-dolinitro-9-fluorenone. However, this photoreceptor also has insufficient sensitivity and durability. Therefore, a functionally separated electrophotographic photoreceptor was developed in which the photosensitive layer contains a separate carrier-generating substance and a carrier-transporting substance. This is because the carrier generation function and the carrier transport function can be assigned to different substances individually, and the substances that exhibit each function can be selected from a wide range of materials. Photoreceptors can be obtained relatively easily. Therefore, it is expected that organic photoreceptors with high sensitivity and durability can be obtained.

A large number of substances have been proposed as carrier-generating substances that can be used in such functionally separated electrophotographic photoreceptors. Examples of using inorganic substances include, for example,
Examples include amorphous selenium as described in Japanese Patent No. 3-16198. This carrier generation layer containing amorphous selenium is used in combination with a carrier transport layer containing an organic carrier transport substance. However, as described above, a photosensitive layer containing amorphous selenium has a problem in that it is crystallized by heat or the like and its properties deteriorate.

Furthermore, examples of using an organic substance as the carrier generating substance include organic dyes and organic pigments. For example, those having a photosensitive layer containing a bisazo compound are disclosed in JP-A-47-37543 and JP-A-55-22.
This is already known from Japanese Patent Application Laid-open No. 834, Japanese Patent Application Laid-Open No. 54-79632, and Japanese Patent Application Laid-open No. 56-116040. However, although these known bisazo compounds exhibit relatively good sensitivity in the short or medium wavelength range, they have low sensitivity in the long wavelength range, making them difficult to use in laser printers that use semiconductor laser light sources that are expected to have high reliability. It was difficult to use.

Gallium-aluminum-arsenide (Ga-AA-As) light emitting devices, which are currently widely used as semiconductor lasers, have an oscillation wavelength of about 750 nm or more. In order to obtain an electrophotographic photoreceptor with high sensitivity to such long wavelength light,
Many studies have been made in the past. For example, a method has been considered to add an exacerbating agent to make the wavelength longer in photosensitive materials such as Se and CdS, which have high sensitivity in the visible light region, but as mentioned above, Se and CdS are There is a problem with insufficient environmental resistance against such things. Furthermore, as mentioned above, the sensitivity of many known organic photoconductive materials is usually limited to the visible light region of 700 nm or less, and there are few materials that have sufficient sensitivity in longer wavelength regions.

Among these, phthalocyanine compounds, which are one of the organic photoconductive materials, are known to have a photosensitive range extended to longer wavelength regions than other compounds. Various crystalline forms of phthalocyanine have been discovered in the process of converting α-type phthalocyanine into stable crystalline β-type phthalocyanine. Examples of these phthalocyanine compounds exhibiting photoconductivity include τ-type metal-free phthalocyanine described in JP-A-58-182639.

As shown in Fig. 10, this τ-type metal-free phthalocyanine is produced by CuKα characteristic X-ray (wavelength: 1.5, 0)
This X-ray is written as Cu K cx (1,541 people).

), the Bragg angle 2θ is 7.6 degrees, 9.2 degrees, 1
It has peaks at 6.8 degrees, 17.4 degrees, 20.4 degrees, and 20.9 degrees, respectively. In addition, in the infrared absorption spectrum, 7
752±2crn-' between 00 and 760cm''
4 absorption bands are the strongest, 2 absorption bands of almost the same strength between 1320 and 1340, 3288 ± 2 cm-'
has a characteristic absorption band. However, this τ-type metal-free phthalocyanine is produced by combining α-type metal-free phthalocyanine with a grinding aid such as salt and an inert organic solvent such as ethylene glycol at 50 to 180°C, preferably 60 to 130°C.
The manufacturing method is complicated and difficult because it is manufactured by keeping it wet for 20 hours.

Therefore, it is not always possible to obtain a τ-type phthalocyanine having a certain crystal form, and when this is used as a carrier generating material, the properties of an electrophotographic photoreceptor are insufficiently stable.

In addition, as a phthalocyanine compound, for example,
X-type metal-free phthalocyanine described in JP-A-4338 is also known. This X-type metal-free phthalocyanine is relatively easy to manufacture compared to the above-mentioned τ-type metal-free phthalocyanine, and has crystal stability and potential stability for repeated use when used as a carrier generating material for electrophotographic photoreceptors. Although the quality is also good, it is still insufficient.

By the way, known photoreceptors using organic photoconductive substances are generally used for negative charging. The reason for this is that when negatively charged, the mobility of holes among carriers is high, which is advantageous in terms of photosensitivity and the like.

However, it has been found that using such negative charging causes the following problems. That is, the first problem is that ozone is likely to be generated in the atmosphere when negatively charged by the charger, worsening the environmental conditions. Another problem is that positive polarity toner is required for development of negatively charged photoreceptors, but positive polarity toner is difficult to manufacture due to the frictional electrification series for ferromagnetic carrier particles. .

Therefore, it has been proposed to use a positively charged photoreceptor using an organic photoconductive substance. For example, in the case of a positively charging photoreceptor in which a carrier transport layer is laminated on a carrier generation layer and the carrier transport layer is formed of a substance with high electron transport ability, the carrier transport layer contains trinitrofluorenone or the like. is unsuitable because it is carcinogenic. On the other hand, a positive charging photoreceptor may be considered in which a carrier generation layer is laminated on a carrier transport layer with a large hole transport ability, but this has poor rigidity etc. due to the presence of a very thin carrier generation layer on the surface side. , this is not a practical layer configuration.

In addition, as a photoreceptor for positive charging, U.S. Patent No. 361541
Specification No. 4 discloses a material containing a thiapyrylium salt (carrier generating substance) so as to form a eutectic complex with polycarbonate (binder resin). However, this known photoreceptor has the drawbacks of a large memory phenomenon and a tendency to generate ghosts. U.S. Patent No. 33579
No. 89 also discloses a photoreceptor containing phthalocyanine, but the characteristics of phthalocyanine change depending on the crystal type, and it is necessary to strictly control the crystal type. It is not suitable for copying machines that use a light source in the visible light wavelength range because of the insufficient amount of light and the large memory phenomenon.

Due to the above-mentioned circumstances, conventionally, it has been difficult to use a photoreceptor using an organic photoconductive substance for positive charging, and for this reason, it has been used mostly for negative charging.

C.9 Purpose of the Invention The purpose of the present invention is to provide a device that has sufficient sensitivity to relatively long wavelength light such as semiconductor laser light and can operate with positive charging;
In particular, it is an object of the present invention to provide a photoreceptor that generates less ozone, can maintain favorable environmental conditions, has excellent rigidity resistance, potential stability, memory characteristics, and residual potential characteristics, and is relatively easy to manufacture.

20 Structure of the invention and its effects The present invention provides a photoreceptor having a photosensitive layer containing a carrier generating substance and a binder substance.
The main peak of the Bragg angle 2θ for a wavelength of 1.541 people) is at least 7.5 degrees ± 0.2 degrees, 9.1 degrees ± 0.
2 degrees, 16.7 degrees ± 0.2 degrees, 17.3 degrees ± 0.2 degrees, and 22.3 degrees ± 0.2 degrees, metal-free phthalocyanine is contained in the photosensitive layer; The present invention relates to a photoreceptor characterized in that it also contains a carrier transporting substance.

According to the present invention, a single-phase photoreceptor is obtained in which the photosensitive layer contains both a carrier-generating substance and a carrier-transporting substance, and is particularly suitable for use with positive charging. Moreover, since metal-free phthalocyanine having the above-mentioned main peak of the Bragg angle is used as the carrier generating substance, the potential stability during repeated use of the photoreceptor is improved, there is little memory phenomenon, and there is little residual potential. In addition, the crystals of the phthalocyanine itself are stable, and its production is easy. In addition, since this metal-free phthalocyanine exhibits high sensitivity in a long wavelength region, the photoreceptor of the present invention is suitable for semiconductor lasers and the like.

Further, according to the photoreceptor of the present invention, since the photoreceptor layer has a single-phase structure in which a carrier-generating substance and a carrier-transporting substance are bound together by a binder substance, sufficient rigidity resistance can be obtained. , manufacturing is also relatively easy. That is, it is sufficient to provide a single photosensitive layer on a conductive substrate, etc., and at this time, the film thickness of the photosensitive layer is 10 to 50 μm (preferably 15 to 30 μm).
By setting the thickness to .mu.m), good printing durability and sensitivity can be easily obtained.

However, when only a carrier-generating substance is contained in a photosensitive layer having a relatively thick single-phase structure as described above, as the film thickness increases, the concentration of the carrier-generating substance in the layer decreases relatively. As the transport distance of positive and negative carriers (holes, electrons) increases, the carrier transport ability decreases, resulting in deterioration of the photosensitive layer.

In contrast, in the present invention, since the photosensitive layer also contains a carrier transport substance, even if the thickness of the photosensitive layer increases, the ability to transport carriers generated within the photosensitive layer does not decrease, but rather improves. do. That is, the inclusion of this carrier transporting substance makes it possible to realize a photosensitive layer suitable for use with positive charging. However, it is desirable that the ionization potential of this carrier-transporting substance be matched to that of the carrier-generating substance.

The present invention makes it possible to provide a positively charged photoreceptor, which makes it possible to exhibit its unique features, generate less ozone, reduce dirt on the discharge electrode, and improve environmental conditions. . Moreover, since it is a functionally separated type, it has high sensitivity and high durability, and the selection of constituent materials is also easy.

In the present invention, the metal-free phthalocyanine described above has an X-ray diffraction spectrum as shown in FIG. That is, as shown in this metal-free phthalocyanine, Cu
The Black angle (error: 2θ±0.2 degrees) of Kα (1,541 people) with respect to X-rays is 7.5.9.1.16.
It has a peak at 7.17.3.22.3 degrees, and a characteristic peak not found in the τ type at a Bragg angle of 22.3 degrees. In addition, its infrared absorption spectrum has three peaks at 746 cm-' and 700 to 750 cm-', and 1318 cm-' and 1330 cm-' as shown in Figure 2.
There are two peaks of equal intensity.

Furthermore, in the present invention, as shown in FIG.
The Bragg angle 2θ (however, the error is 2θ ± 0.2 degrees) for the X-ray of ゜541 people) is 7.7.9゜3.16.9
．． 17.5.22.4. has an X-ray diffraction spectrum with a major peak at 28.8 degrees, and a Bragg angle of 16.9 with respect to the peak at the Bra-knob angle of 9.3 degrees in this X-ray diffraction spectrum The intensity ratio of the peak of the degree is 0.8 to 1
．． 0, and the intensity ratio of the peaks at Bragg angles of 22.4 and 28.8 degrees to the peak at Bragg angle of 9.3 degrees is 0.4 or more. This phthalocyanine has a characteristic peak at a Bragg angle of 28.8 degrees compared to that in FIG.

As is clear from FIG. 3, the τ-type metal-free phthalocyanine shown in FIG.
The intensity ratio of the peak at a Bragg angle of 16.9 degrees to the peak at a Bragg angle of 9.2 degrees corresponding to the former intensity ratio is 0.9 to 1.0, but for the latter intensity ratio, one Bragg angle However, for the metal-free phthalocyanine shown in Figure 1, the Bragg angle is 16.7 degrees with respect to the peak of the Bragg angle of 9.1 degrees, which corresponds to the former intensity ratio. The difference is that for the latter intensity ratio, there is no peak corresponding to the Bragg angle of 28.8 degrees, so the intensity ratio cannot be determined.

Furthermore, the infrared absorption spectrum of the metal-free phthalocyanine shown in Fig. 3 is 700 to 760 cm-' as shown in Fig. 4.
Between them, 720±2CI11-' is the strongest four absorption bands, 1320±2CI+1-', 3288±3cna-'
It is desirable that the τ-type metal-free phthalocyanine has an absorption characteristic of 700 to 760 cm-
752±2 (J-' has the strongest four absorption bands between differs from the infrared absorption spectrum of metal-free phthalocyanine in Figure 1 in the intensity ratio of the peak at 700 to 760 cm-', and also has a characteristic absorption at 3288 ± 3 cm-' with an absorption band at 1330 cm-'. It differs in that it has

In addition, the visible and near-infrared absorption spectrum of the metal-free phthalocyanine in Figure 3 is 770 nm, as shown by the solid line in Figure 5.
It is desirable that the absorption maximum be at m or more and less than 790 nm, and the τ-type metal-free phthalocyanine shown by the broken line is 790 to 8
It has an absorption maximum at 20 nm, and many have an absorption maximum at about 810 nm.

In order to produce the metal-free phthalocyanine of the present invention, the α-type metal-free phthalocyanine is stirred for a sufficient time to undergo crystal transition, or mechanical strain (for example, kneading) is applied.
The metal-free phthalocyanine shown in Fig. 1 is obtained by milling with the phthalocyanate, and then the metal-free phthalocyanine shown in Fig. 3 is obtained by subjecting this metal-free phthalocyanine to solvent treatment such as dispersion treatment with a non-polar solvent such as tetrahydrofuran. . For milling with stirring or kneading, dispersion media commonly used for dispersing, emulsifying, and mixing pigments, such as glass beads, steel beads, etc.
Alumina balls, flint stones, etc. are used. but,
Distributed media is not necessarily required. A grinding aid may also be used, and as this grinding aid, those commonly used for pigments may be used, such as common salt, bicarbonate of soda, sulfur salt, and the like. However, this grinding aid is also not necessarily required.

If a solvent is required during stirring, kneading, or grinding, it is best to use a solvent that is liquid at the temperature during these operations.
Examples of such solvents include alcohol-based solvents such as glycerin, ethylene glycol, diethylene glycol, or polyethylene glycol-based solvents, cellosolve-based solvents such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, ketone-based solvents, and ester-ketone-based solvents. It is preferable to select one or more solvents selected from the group.

Typical devices used in the crystal transition process include general stirring devices such as homomixers, dispersers, agitators, starters, kneaders, Banbury mixers, ball mills, sand mills, and attritors. be.

The superior properties of the metal-free phthalocyanine of the present invention produced as described above are such that the production method does not necessarily require a grinding aid and therefore does not require its removal, and temperature control is possible. The method for producing τ-type phthalocyanine does not have to be strict, for example, it can be done at room temperature. is different.

In addition, the metal-free phthalocyanine of the present invention has an extremely stable crystalline form and can be immersed in an organic solvent such as acetone, tetrahydrofuran, toluene, ethyl acetate, or 1,2-dichloroethane, or exposed for 50 hours in an atmosphere at 200°C. It is difficult for transformation to other crystal forms to occur even when subjected to heat resistance tests such as leaving it for more than 30 minutes, or applying mechanical strain such as milling.
This is of course more valuable than the conventional τ type (this point is the third
The phthalocyanine shown in the figure is particularly good). This means that
This makes it possible to manufacture the metal-free phthalocyanine of the present invention with less fluctuation in its quality, and in addition to the above, it further facilitates its manufacture, and also makes it possible to reduce the fluctuation in quality when used in electrophotographic photoreceptors. Characteristics such as potential stability and durability can be improved.

The above-mentioned metal-free phthalocyanine used in the present invention has the following structural formula, and is mainly divided into those shown in FIG. 1 and those shown in FIG. 3 depending on its thermodynamic state.

In addition to this metal-free phthalocyanine, other carrier-generating substances may be used in combination. Carrier generating substances that can be used in combination include, for example, α-type, β-type, τ-type, τ-type,
Examples include τ" type, η type, and η" type metal-free phthalocyanine. Other examples include phthalocyanine pigments, azo pigments, anthraquinone pigments, perylene pigments, polycyclic quinone pigments, and methine squaric acid pigments other than those mentioned above.

Examples of azo pigments include the following.

(I-1) (I-4) A-N=N-Ar'-CH=CH-Ar"-N=N-A
A-N=N-Ar'-CH=CH-Ar''-CH=CH
-Ar5-N=N-A (I-7) A-N=N-Ar'-N=N-Ar"-N=N-A(T
-9) A-N=N-Ar'-N=N-Ar"-N=N-Ar
3-N=N-A IRZ A-N=N-Ar'-C=C-Ar"-N=N-A(I
-11) -N=N-A [However, in each of the above general formulas, Ar', Ar2 and Ar': each substituted or unsubstituted carbocyclic aromatic ring group, R1, R2, R3, each electron an electron-withdrawing group and R4 or a hydrogen atom, at least one of R1-R4 is an electron-withdrawing group such as a cyano group, a hydrogen atom or a substituted or unsubstituted alkyl group, R8 is a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkyl group>, Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, Alkoxy group, carboxyl group, sulfo group, substituted or unsubstituted carbamoyl group, or substituted or unsubstituted sulfamoyl group (however, when m is 2 or more, mutually different groups may be used), Z is substituted or an atomic group necessary to constitute an unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring, R5 is a hydrogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted A carbamoyl group, a carboxyl group or an ester group thereof, AY' is a substituted or unsubstituted aryl group, n is an integer of 1 or 2, m is an integer of 0 to 4.)] Also, the following general formula Polycyclic quinone pigments of the (If) group can also be used in combination as carrier-generating substances.

General formula (II) (However, in this general formula, G is a halogen atom, a nitro group,
It represents a cyano group, an acyl group or a carboxyl group, p represents an integer of 0 to 4, and q represents an integer of 0 to 6. ) The structure of the photosensitive layer of the electrophotographic photoreceptor based on the present invention is explained in the sixth section.
An example is shown in FIG.

FIG. 6 shows photosensitive N2 in which the carrier-generating substance 2a and the carrier-transporting substance 2b are dispersed in a binder substance.
It is provided on a conductive support 1. In the structure shown in FIG. 7, an intermediate layer 3 is provided between the photosensitive layer 2 and the conductive support 1 having the layer structure shown in FIG. 6, and the injection of free electrons into the conductive support 1 is effectively prevented. It was designed to do so. As the intermediate N3, a material made of a high molecular weight polymer as described above as the binder resin, an organic polymer material such as polyvinyl alcohol, ethyl cellulose, or carboxymethyl cellulose, or aluminum oxide is used.

In FIGS. 6 and 7, a protective layer (film) may be further formed on the surface to improve printing durability, for example, a synthetic resin film may be coated.

The photosensitive layer N2 having the above structure can be provided by the following method.

(a) A method of applying a solution in which a carrier-generating substance is dissolved in a suitable solvent, or a solution in which a binder is added and mixed and dissolved.

(b) A method in which a carrier-generating substance is made into fine particles in a dispersion chamber using a ball mill, a homomixer, etc., and a binder is added as necessary to mix and disperse the obtained dispersion, and the resulting dispersion is applied.

Dispersing the particles under the action of ultrasound in these methods allows for homogeneous dispersion.

Examples of the solvent or dispersion medium used for forming the photosensitive layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine,
Triethylenediamine, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone,
Benzene, toluene, xylene, chloroform, 1.2
- Dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide and the like.

When a binder is used to form the photosensitive layer, any binder can be used, but a hydrophobic polymer having a high dielectric constant and the ability to form an electrically insulating film is particularly preferred. Examples of such polymers include, but are not limited to, the following:

a) Polycarbonate b) Polyester C) Methacrylic resin d) Acrylic resin e) Polyvinyl chloride f) Polyvinylidene chloride g) Polystyrene h) Polyvinyl acetate i) Styrene-butadiene copolymer j) Vinylidene chloride-acrylonitrile copolymer k) Vinyl chloride-vinyl acetate copolymer ■) Vinyl chloride-vinyl acetate-maleic anhydride copolymer m) Silicone resin n) Silicone-alkyd resin 0) Phenol-formaldehyde resin p) Styrene-
Alkyd resin q) Poly-N-vinylcarbazole r) Polyvinyl butyral These binders can be used alone or in a mixture of two or more.

In the photosensitive layer of the photoreceptor according to the present invention, the carrier generating substance is added to the binder substance in an amount of 5 to 150% (carrier generating substance/binder substance = 5 to 150 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the binder substance). If the content is within a specific range of 100 parts by weight), it is possible to provide a positively charging photoreceptor with less reduction in residual potential and acceptance potential. Outside the above range, if the amount of the carrier generating substance is small, the photosensitivity will be insufficient and the residual potential will increase, and if it is too large, the acceptance potential will decrease more and the memory will tend to increase. In addition, the content of the carrier transport substance in the photosensitive layer is also important;
Binder material = 20-200% (i.e. binder material rt
20 to 200 parts by weight per 100 parts by weight, preferably 5 parts by weight
(0 to 120 parts by weight); within this range, the residual potential is small and the photosensitivity is good, and the solvent solubility of the carrier transport substance is also maintained well. Outside this range, if the amount of carrier transport substances is small, the residual potential and photosensitivity are likely to deteriorate, resulting in poor images, white spots, blurring, etc.; , there is a tendency for image defects to occur.

In addition, the ratio of the carrier-generating substance and the carrier-transporting substance in the photosensitive layer is such that the weight ratio of the carrier-generating substance to the carrier-transporting substance is (1:0.2) so that the respective functions of both substances can be effectively exhibited. ) to (1:10) is desirable, and (1:0.5) to (1:7) is even better.

If the proportion of the carrier-generating substance is smaller than this range, the photosensitivity will be insufficient, and if the proportion is large, the carrier transport ability will decrease, resulting in insufficient sensitivity.

In the above, the thickness of the photosensitive layer 2 is preferably 10 to 50 μm, more preferably 15 to 30 μm. If the film thickness is less than 15 μm, the charging potential will be low due to the thinness, and the rigidity resistance will also be poor. In addition, when the thickness of the photosensitive layer 2 exceeds 50I1m, the residual potential increases, the number of thermally excited carriers increases, and as the environmental temperature increases, the accepted potential decreases and the memory phenomenon increases. ,
A decrease in density on the image is likely to occur. Furthermore, when irradiating light with a wavelength longer than the absorption edge of the carrier-generating substance, photocarriers are generated even near the bottom of the charge-generating layer. In this case, electrons must move through the layer to the surface, and generally sufficient transport ability tends to be difficult to obtain. Therefore,
Residual potential tends to increase during repeated use.

When the photosensitive layer is formed by dispersing the carrier-generating substance, the carrier-generating substance has a thickness of 5 μm or less,
It is preferable that the powder has an average particle diameter of 0.1 μm or more, preferably 2 μm or less, and 0.2 μm or more. In other words, if the particle size is too large, dispersion in the layer will be poor, and some of the particles will protrude from the surface, resulting in poor surface smoothness.
In some cases, discharge may occur at the protruding portions of the particles, or toner particles may adhere to the protruding portions, causing a toner filming phenomenon. Long wavelength light (
700 nm), the surface charge is neutralized by the generation of thermally excited carriers in the carrier-generating substance, and this neutralization effect seems to be greater when the particle size of the carrier-generating substance is large. .

Therefore, high resistance and high sensitivity can only be achieved by reducing the particle size. However, if the particle size is too small, it tends to aggregate, which increases the resistance of the layer, increases crystal defects, reduces sensitivity and repeatability, and reduces charging ability. Also, there are limits to miniaturization, so
It is desirable that the lower limit of the average particle size is 0.01 μm.

Furthermore, the photosensitive layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use. Examples of electron-accepting substances that can be used here include succinic anhydride, maleic anhydride, dibromosuccinic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromo phthalic anhydride, 3-nitro phthalic anhydride, 4- Nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitropenzea, 1,3,5-trinitrobenzene, varanitrobenzonitrile, bicri chloride, quinone chlorimide, chloranil, brumanil, dichlorodicyanobarabenzoquinone, anthraquinone, dinitroanthraquinone, 9-fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene [dicyanomethylenemalonodinitrile], picric acid , 0-nitrobenzoic acid, p-nitrobenzoic acid, 5-nitrosalcylic acid, 3.5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalcylic acid, 3.5-dinitrosalicylic acid, phthalic acid, mellitic acid , and other compounds with high electron affinity. In addition, the addition ratio of the electron-accepting substance is carrier-generating substance:electron-accepting substance in weight ratio of 100:0.0.
The ratio is 1 to 200, preferably 100:0.1 to 100.

The support 1 on which the photosensitive layer is to be provided is a metal plate, a metal drum, or a conductive thin layer made of a conductive polymer, a conductive compound such as indium oxide, or a metal such as aluminum, palladium, or gold, which is coated or vapor-deposited. , a material provided on a substrate such as paper or plastic film by means such as lamination or the like is used. The intermediate layer that functions as an adhesive layer or barrier layer may be made of a polymer such as the binder resin described above, an organic polymer material such as polyvinyl alcohol, ethyl cellulose, or carboxymethyl cellulose, or aluminum oxide. used.

As described above, an electrophotographic photoreceptor according to the present invention is obtained, but when the photoreceptor layer constituting this photoreceptor has a structure in which a granular carrier-generating substance and a carrier-transporting substance are solidified with a binder substance. Because the carrier-generating substance is granular and dispersed in the form of pigment in the photosensitive layer,
There is little memory phenomenon and the residual potential is stable.

A major feature of the photoreceptor of the present invention is that the maximum value of the photosensitive wavelength range of the metal-free phthalocyanine used in the present invention is 770 nm.
m or more and less than 790 nm, it is optimal as a photoreceptor for semiconductor lasers, and as mentioned above, this metal-free phthalocyanine has an extremely stable crystal form, and transition to other crystal forms is difficult to occur. . This is a great advantage not only in the production and properties of the metal-free phthalocyanine used in the present invention, but also in the production and use of electrophotographic photoreceptors.

E. Examples Hereinafter, the present invention will be explained in detail with reference to specific examples and comparative examples.

First, a synthesis example of a metal-free phthalocyanine compound A having the properties shown in FIGS. 1 to 2, a metal-free phthalocyanine compound B having the properties shown in FIGS. 3 to 5, and a synthesis example of a τ-type metal-free phthalocyanine compound. shows.

<Synthesis Example 1> 50 g of lithium phthalocyanine was added to 600 ml of concentrated sulfuric acid that had been sufficiently stirred at 0°C. The mixture was then stirred at this temperature for 2 hours.

The resulting solution was then filtered through a coarse sintered glass funnel and poured slowly into 4 liters of ice and water with stirring. After standing for several hours, the mixture was filtered and the resulting mass was washed with water until neutral. The mass was then finally washed several times with methanol and dried in air. This dried powder was extracted with acetone in a 24 hour continuous extractor,
and dried in air to form a blue powder.

In the above, the precipitation was repeated to ensure a salt residue for lithium. 30.5 g of blue powder was thus obtained. The X-ray diffraction pattern of the obtained product was consistent with the X-ray diffraction pattern of an α-type phthalocyanine compound described in previously published materials.

30 g of the metal-free α-type phthalocyanine compound thus obtained was charged into a porcelain ball mill with an internal volume of 900 ml, half-grooved with 13/16-inch diameter balls, and milled at approximately 8 Orpm for 164 hours. A metal-free phthalocyanine compound A was obtained. This compound is the first
The X-ray diffraction spectrum shown in the figure is shown.

Synthesis Example 2> The metal-free phthalocyanine compound A of Synthesis Example 1 was dissolved in an organic solvent such as tetrahydrofuran, 1,2-dichloroethane, etc.
ml was added into a ball mill and milled again for 24 hours. After this milling, the dispersion was removed from the organic solvent and dried to form a metal-free phthalocyanine compound 828.
．． 2g was obtained. This compound exhibited the X-ray diffraction spectrum shown in FIG.

Synthesis Example 3 An α-type metal-free phthalocyanine compound (Monolite Fast Pull GS manufactured by ICI) was extracted and purified three times with heated dimethyl formaldehyde. Through this operation, the purified product was transferred to the β form. Next, a portion of this β-type metal-free phthalocyanine compound was dissolved in concentrated sulfuric acid, and the solution was poured into ice water to re-precipitate, thereby converting it to the α-type. This reprecipitate was washed with aqueous ammonia, methanol, etc., and then dried at 10°C. Next, the α-type metal-free phthalocyanine compound purified as described above was placed in a sand mill together with a grinding aid and a dispersant, and kneaded at a temperature of 100±20° C. for 15 to 25 hours. After confirming that the crystal form has changed to the τ type by this operation, take it out from the container, thoroughly remove the grinding aid and dispersant with water and methanol, etc., and dry it to form a clear bluish τ. Blue crystals of type-free metal phthalocyanine were obtained. This phthalocyanine showed the X-ray diffraction spectrum shown in FIG.

fj11-12, r11-3 Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer “S-LEC MF-10J
(manufactured by Mikki Kagaku Co., Ltd.) with a thickness of 0.05 μm was formed. Next, each carrier generating substance and each carrier transporting substance having an average particle size of 1 μm shown in FIG. 8 and a binder resin polycarbonate (Panlite L-1250) were added to 67 ml of 1,2-dichloroethane and dispersed in a ball mill for 12 hours. The resulting dispersion was applied onto the intermediate layer and dried to form a photosensitive layer, thereby producing each electrophotographic photoreceptor.

The electrophotographic photoreceptor thus obtained was tested using an electrostatic tester rE.
The following characteristic tests were carried out by attaching the device to a model PA-8100 (manufactured by Kawaguchi Electric). That is, +6KV to the charger
The photosensitive layer was charged by corona discharge for 5 seconds by applying a voltage of The amount of exposure necessary to attenuate by 1/2,
That is, the half-reduced exposure amount E1/2 was determined. In addition, the acceptance potential VA and 101 ux・se when charged by the above corona discharge
c The value of residual potential vR after exposure was measured.

Further, a photoreceptor layer similar to that shown in the example was formed on an Al drum, and a laser beam printer LP-30 was used.
10 (manufactured by Konishi Roku Photo Industry ■) to carry out image evaluation using a modified machine (using a semiconductor laser light source) (where CD is image density and R is resolution).

◎: Density is sufficiently high and resolution is also very good.

(CD≧1.2, R≧6.0) ○: Good density and resolution.

(1,2>CD; i:0.7, 6.0>R≧4.0
)×: The density is low and the resolution is not sufficient. Also, capri and white or black spots appear.

In addition, CD is Sakura Densitometer (Model PDA
R is measured using a Sakura densitometer (Model PDM-5: manufactured by Konishiroku Photo Industry). For both CD and R, set the density of the blank paper to 0.
．． 0, and the reflection density was measured and evaluated.

However, the specific measuring method for R was as follows. That is, a resolution chart is measured using a microdensitometer with a slit of 500 μ×20 μ. The determination criteria for the resolving power chart is based on the resolving power chart in which the following equation has a response of 30% or more. The density of the resolved part of the copy resolution is D; O, Me', and the density of the non-image part is D'a.
:”:,',Densitize the image area density of the original manuscript9.
If the density of the non-image area is D"Ri%9, then Dor
i* +Dori9 -sctz -WL+ According to the results, it can be seen that all the samples of Examples 1 to 12 exhibit significantly better electrophotographic properties than Comparative Examples 1 to 3 based on the present invention. . In particular, using the metal-free phthalocyanine of the present invention as CGM and also adding CTM to the carrier generation layer greatly influences the characteristics of the photoreceptor, improving the high charging potential and stability, and improving the photosensitivity. It is possible to obtain remarkable results as a positive charging photoreceptor, such as greatly improving the performance. Tests using semiconductor lasers also revealed that high density and high resolution were obtained, and long wavelength sensitivity was improved.

Male side 13 to 24, Comparative example 4 Each electrophotographic photoreceptor was produced in the same manner as in Examples 1 to 12 and Comparative example 3, except that the carrier generating substance used was changed to metal-free phthalocyanine compound B, When a similar test was conducted, the results shown in FIG. 9 were obtained.

From this result, it was found that the samples of Examples 13 to 24 based on the present invention all showed good results, but the sample of Comparative Example 4, in which no carrier transport substance was added to the carrier generation layer, had insufficient characteristics. Ru.

[Brief explanation of the drawing]

FIGS. 1 to 9 illustrate the present invention, and FIGS. 1 and 3 show each X on the two sides of the metal-free phthalocyanine.
Line diffraction spectrum, Figures 2 and 4 are infrared absorption spectra of the two sides of metal-free phthalocyanine, Figure 5 is near-infrared spectrum of metal-free phthalocyanine, Figures 6 and 7 are electronic photographs. Each cross-sectional view of a portion of the two sides of the photoreceptor, FIGS. 8 and 9, are diagrams comparing and showing changes in characteristics depending on the composition of each electrophotographic photoreceptor. FIG. 10 is an X-ray diffraction spectrum diagram of a conventional τ-type metal-free phthalocyanine. In addition, in the symbols shown in the drawings, 1...--Conductive support 2---Photosensitive layer 2a--Carrier generating substance 2b・-・・
-.-Carrier transport material 3--...- Intermediate layer. Agent Patent Attorney Hiroshi Aisaka Figure 1 Figure 3 2e (deg) (cumtt54+persons) Transparent cloth (%) Figure 5 Length (nm) Figure 6 Figure 7 Figure 10 X-Sun diffraction spectrum Figure (spontaneous) Procedure Nei City Official Book 1985, Month S Day 1, Display of the case 1986 Patent Application No. 295784 2, Name of the invention Photoreceptor 3, Person making the amendment Relationship to the case Patent applicant residence Address: 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name:
(127) Konishiroku Photo Industry Co., Ltd. 4, Agent address: FINIE Building, 2-4il Shibasaki-cho, Tachikawa-shi, Tokyo TEL O=! 2 5 - 2 4
- 5 4 1 1 (4', j6, number of inventions increased by 7 due to amendment, subject of amendment (1), "single-phase type" on page 10, line 6 of the specification was corrected to "single-layer type") (2) Correct "single-phase structure" in the second line from the bottom of page 10 to "single-layer structure." (3) Correct "single-phase structure" in line 7 of page 11 to "single-layer structure." Correct it as "single-layer structure." (4), "τ° type, η type, η
′ type” is corrected to “τ′ type, η type, η′ type.” (5) In the first line from the bottom of page 26, "in the dispersion term" is corrected to "in the dispersion medium." (6), on page 32, lines 5 to 4 from the bottom, "tetrabromofukuric anhydride" has been corrected to "tetrabromophthalic anhydride." One or more -

Claims (1)

[Claims] 1. In a photoreceptor having a photosensitive layer containing a carrier-generating substance and a binder substance, CuKα characteristic X-rays (wavelength 1
．． 541 Å) at least 7.5 degrees ± 0.2 degrees, 9.1 degrees ± 0.2 degrees, 1
6.7 degrees ±0.2 degrees, 17.3 degrees ±0.2 degrees and 22.
A photoreceptor characterized in that the photosensitive layer contains metal-free phthalocyanine at an angle of 3 degrees ±0.2 degrees, and further contains a carrier transporting substance in the photosensitive layer.