JPH0518423B2 - - Google Patents

Description

[Detailed description of the invention]

B. Field of Industrial Application The present invention relates to a photoreceptor, particularly an electrophotographic photoreceptor. B. Prior Art Conventionally, electrophotographic photoreceptors sensitive to visible light have been widely used in copying machines, printers, and the like. Such electrophotographic photoreceptors include selenium,
Inorganic photoreceptors provided with a photosensitive layer mainly composed of an inorganic photoconductive substance such as 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. Further, electrophotographic photoreceptors made of selenium or cadmium sulfide have the disadvantage that there are significant restrictions 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, Tokkosho
No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly N-vinylcarbazole and 2,4,7-trinitro-9-fluorenone. However, this photoreceptor also has insufficient sensitivity and durability. Therefore, a functionally separated electrophotographic photoreceptor has been developed in which the photosensitive layer is divided into two layers, a carrier generation layer and a carrier transport layer are separately configured, and each layer contains a carrier generation substance and a carrier transport substance. This is because the carrier generation function and the carrier transport function can be assigned to different substances, and the substances that perform each function can be selected from a wide range of substances.
An electrophotographic photoreceptor having arbitrary characteristics can be obtained relatively easily. Therefore, it is expected that organic photoreceptors with high sensitivity and durability can be obtained. Carrier generating substances that are effective for the carrier generating layer of such a functionally separated electrophotographic photoreceptor include:
Many substances have been proposed so far. An example of using an inorganic substance is amorphous selenium, as described in Japanese Patent Publication No. 16198/1983. This carrier generating layer containing amorphous selenium is used in combination with a carrier transport layer containing an organic carrier transport material. However, as described above, this carrier generation layer made of amorphous selenium has the problem 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, as a device having a photosensitive layer containing a bisazo compound,
JP-A-47-37543, JP-A-55-22834, JP-A-54-79632, JP-A-56-116040
This is already known from publications such as No. However, although these known bisazo compounds exhibit relatively good sensitivity in the short or medium wavelength range, their sensitivity in the long wavelength range is low, making them difficult to use in laser printers that use semiconductor laser light sources, which are expected to be highly reliable. That was difficult. Currently, gallium-aluminum-arsenic (Ga-Al-Arsenic) is widely used in semiconductor lasers.
As) type light emitting elements have an oscillation wavelength of about 750 nm or more. Many studies have been made in the past in order to obtain electrophotographic photoreceptors that are highly sensitive to such long wavelength light. For example, it has high sensitivity in the visible light region.
A method of adding a new sensitizer to photosensitive materials such as Se and CdS to make the wavelength longer has been considered, but Se, CdS, etc.
As mentioned above, CdS does not have sufficient environmental resistance against temperature, humidity, etc., and there are still problems. 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 Cu Kα characteristic X-ray (wavelength 1.541 Å) (hereinafter referred to as
This X-ray is written as Cu Kα (1.541 Å). ), the black angle 2θ is 7.6 degrees, 9.2 degrees, 16.8 degrees, 17.4 degrees,
It has peaks at 20.4 degrees and 20.9 degrees, respectively. In addition, in the infrared absorption spectrum, there are four absorption bands between 700 and 760 cm ^-1 with the strongest at 752 ± 2 cm ^-1 , and 1320
Two absorption bands of approximately equal strength between ~1340 cm ^-1 ,
There is a characteristic absorption band at 3288±2cm ^-1 . However, this τ-type metal-free phthalocyanine is
Type-free metal phthalocyanine is mixed with grinding aids such as salt and inert organic solvents such as ethylene glycol.
The manufacturing method is complicated and difficult because it is manufactured by wet kneading at ~180°C, preferably 60~130°C for 5 to 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. Also known as a phthalocyanine compound is, for example, the x-type metal-free phthalocyanine described in Japanese Patent Publication No. 49-4338. This x-type metal-free phthalocyanine is relatively easy to manufacture compared to the above-mentioned τ-type metal-free phthalocyanine, and has good crystal stability and potential stability for repeated use when used as a carrier generating material for electrophotographic photoreceptors. Good, but still not good enough. By the way, known photoreceptors using organic photoconductive substances are generally used for negative charging. The reason for this is that when negative charging is used, the mobility of holes among the carriers is large, 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 triboelectrification series with respect to 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, etc., but this substance is carcinogenic. It is inappropriate due to its gender. 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 high hole transport ability, but this has poor printing durability due to the presence of a very thin carrier generation layer on the surface side. This is not a practical layer structure. In addition, as a photoreceptor for positive charging, the U.S. Patent No.
No. 3,615,414 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. 3,357,989 also discloses a photoreceptor containing phthalocyanine, but the characteristics of phthalocyanine change depending on the crystal type, and the crystal type needs to be strictly controlled. Furthermore, it lacks short wavelength sensitivity and has a large memory phenomenon, making it unsuitable for copying machines that use light sources in the visible wavelength range. 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 exclusively for negative charging. C. Purpose of the Invention The purpose of the present invention is to have sufficient sensitivity to relatively long-wavelength light such as semiconductor laser light, to be able to operate with positive charging, and to have excellent printing durability with particularly low ozone generation. The object of the present invention is to provide a photoreceptor with excellent potential stability, memory characteristics, and residual potential characteristics. D. Structure and Effects of the Invention The present invention provides a photoreceptor in which a carrier transport layer containing a carrier transport substance and a binder substance, and a carrier generation layer containing a carrier generation substance and a binder substance are laminated in this order. Black angle 2θ for X-rays with Kα 1.541Å
(However, the error is 2θ ± 0.2 degrees) is 7.7 degrees, 9.3 degrees, 16.9 degrees
It has an X-ray crystal diffraction spectrum with main peaks at 17.5 degrees, 22.4 degrees, and 28.8 degrees, and the intensity ratio of the peak at a black angle of 16.9 degrees to the peak at a black angle of 9.3 degrees in this X-ray diffraction spectrum is
0.8 to 1.0, and the intensity of each peak at the black angle of 22.4 degrees and 28.8 degrees with respect to the peak at the black angle of 9.3 degrees is 0.4 or more, and
It has an infrared absorption spectrum with peaks at 700 to 760 cm ^-1 , 1320 ± 2 cm ^-1 and 3288 ± 3 cm ^-1 ,
There are four peaks in the absorption band from 700 to 760 cm ^-1 .
The present invention relates to a photoreceptor characterized in that 752±2 cm ^-1 of the metal-free phthalocyanine contains the strongest metal-free phthalocyanine. According to the present invention, a metal-free phthalocyanine having the main peak of the black angle described above is provided in a functionally separated photoreceptor which is particularly suitable for use with positive charging and has a carrier generation layer laminated on the carrier transport layer. Since it uses phthalocyanine as a carrier generating substance, the potential stability during repeated use of the photoreceptor is improved, there is less memory phenomenon, the residual potential is also reduced, and the crystals of the phthalocyanine itself are stable, making it easy to manufacture. It is. In addition, by using this metal-free phthalocyanine, it exhibits high sensitivity even in the long wavelength range, making it a photoreceptor suitable for semiconductor lasers and the like. In addition, the photoreceptor of the present invention has a structure for positive charging because the carrier generation layer is provided as an upper layer, but here, by providing the carrier generation layer thicker, the above-mentioned problems can be solved. The printing durability can be sufficiently satisfied. For example, if the carrier generation layer is provided at a thickness of 0.6 to 10 μm (preferably 1 to 8 μm), which is much thicker than the normally considered thickness (approximately 0.2 μm when using negative charging), printing durability and even sensitivity will be improved. can be improved. However, if the carrier generation layer is provided thickly in this way, the concentration of the carrier generation substance in the carrier generation layer will be relatively low, but in the present invention, the positive and negative carriers generated in the carrier generation layer ( In order to improve rather than reduce the transport ability of holes, electrons), a carrier transport substance is contained in the carrier generation layer. That is, by containing this carrier transport substance, it is possible to realize a layer structure (by providing a thicker upper carrier generation layer) that can withstand use with positive charging. However, this carrier transport substance is
It is desirable that the ionization potential matches the carrier generating substance. According to the present invention, since it is possible to provide a positively charged photoreceptor, its unique features can be exhibited, and it is possible to reduce the amount of ozone generated and reduce the contamination of the discharge electrode. Moreover, since it is a functionally separated type, it has high sensitivity and high durability, and the selection of constituent materials is easy. The metal-free phthalocyanine used in the present invention has a characteristic X-ray diffraction spectrum that is not found in conventional metal-free phthalocyanines (for example, the τ-type metal-free phthalocyanine shown in FIG. 12). That is, it has a characteristic peak at a black angle of 28.8 degrees. For example, as an example of the X-ray diffraction spectrum exhibited by the metal-free phthalocyanine used in the present invention,
Examples include those shown in the figure. Furthermore, the metal-free phthalocyanine used in the present invention has an infrared absorption spectrum with a peak at 700 to 760 cm ^-1 , as shown in Figure 4.
There are four peaks in the cm ^-1 absorption band, of which
It is characterized by being the strongest at 720±2cm ^-1 . In addition, the visibility of metal-free phthalocyanine in Figure 3,
As shown by the solid line in Figure 5, the near-infrared absorption spectrum preferably has an absorption maximum between 770 nm and 790 nm, and the τ-type metal-free phthalocyanine shown by the broken line has an absorption maximum between 790 and 820 nm.
It is different from the one that has an absorption maximum at 810nm. In order to produce the metal-free phthalocyanine according to the present invention, the α-type metal-free phthalocyanine shown in FIG. The metal-free phthalocyanine shown in FIG. 3 is obtained by obtaining a metal-free phthalocyanine and then subjecting the metal-free phthalocyanine to a solvent treatment such as a dispersion treatment with a non-polar solvent such as tetrahydrofuran. For milling with stirring or kneading, a dispersion medium that is normally used for dispersing, emulsifying, or mixing pigments, such as glass beads, etc.
Steel beads, alumina balls, flint stones, etc. are used. However, 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. The metal-free phthalocyanine shown in Figure 1 is Cu
Black angle of Kα (1.541HÅ) to X-rays (error is 2θ±0.2 degrees) 7.5 degrees, 9.1 degrees, 16.7 degrees,
It has peaks at 17.3 degrees and 22.3 degrees, and its infrared diffraction spectrum is 746 cm ^-1 , as shown in Figure 2.
Three peaks between 700 and 750 cm ^-1 , 1318 cm ^-1 ,
There is an equal peak of intensity at 1330 cm ^-1 . If a solvent is required during stirring, kneading, or grinding, it is best to use a liquid one at the temperature at which these operations are being carried out. or 1 selected from the group of polyethylene glycol solvents, cellosolve solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ketone solvents, ester ketone solvents, etc.
It is preferable to select more than one type of solvent. Typical devices used in the crystal transition process include a general stirring device,
For example, there are homomixers, dispersers, agitators, stirrers, kneaders, Banbury mixers, ball mills, sand mills, attritors, etc. 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. Furthermore, the metal-free phthalocyanine of the present invention has an extremely stable crystalline form, and can be immersed in organic solvents such as acetone, tetrahydrofuran, toluene, ethyl acetate, and 1,2-dichloroethane, for example at 200°C.
Even when subjected to heat resistance tests such as being left in an atmosphere of (The phthalocyanine shown in FIG. 3 is particularly good in this respect). 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 can be improved. The above-mentioned metal-free phthalocyanine used in the present invention has the following structural formula, and can be 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. Examples of carrier-generating substances that can be used in combination include α-type,
Examples include β-type, γ-type, τ-type, τ′-type, η-type, and η′-type metal-free phthalocyanine. Other examples include phthalocyanine pigments, azo pigments, anthraquinone pigments, perylene pigments, polycyclic quinone pigments, methine squaritate pigments, and the like. Examples of azo pigments include the following. (1-5) A-N=N-Ar ¹ -CH=CH-Ar ²
-N=N-A (1-6) A-N=N-Ar ¹ -CH=CH-Ar ²
-CH=CH-Ar ³ -N=N-A (1-8) A−N=N−Ar ¹ −N=N−Ar ² −
N=N-A (1-9) A-N=N-Ar ¹ -N=N-Ar ² -
N=N- ^Ar3 -N=N-A [However, in each of the above general formulas, Ar ¹ , Ar ² , and Ar ³ are each a substituted or unsubstituted carbocyclic aromatic ring group, and R ¹ , R ² , R ³ , and R ⁴ are each an electron-withdrawing group. a hydrogen atom, at least one of R ¹ to ^{R 4} is an electron-withdrawing group such as a cyano group, A:

【formula】

【formula】

【formula】

[Formula] Ma Taha

【formula】 (X is a hydroxy group,

[Formula] or -NHSO ₂ -R ⁸ <However, R ⁶ and R ⁷ are each a hydrogen atom or a substituted or unsubstituted alkyl group, and R ⁸ is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group> , Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxyl group, a sulfo group, a substituted or unsubstituted carbamoyl group, or a substituted or unsubstituted sulfamoyl group (provided that m is 2 or more) ), Z is an atomic group necessary to constitute a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring, R ⁵ is a hydrogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof, ^A4 is a substituted or unsubstituted aryl group, n is an integer of 1 or 2, m is an integer from 0 to 4. )] Polycyclic quinone pigments of the following general formula [] group can also be used as carrier generating substances. General formula []: (However, in this general formula, X' is a halogen atom,
It represents a nitro group, a cyano group, an acyl group, or a carboxyl group, n represents an integer of 0 to 4, and m represents an integer of 0 to 6. ) In order to constitute the photosensitive layer of the electrophotographic photoreceptor according to the present invention, for example, as shown in FIG. A photosensitive layer 4 is formed by forming a carrier generating layer 2 on which the carrier generating substance and carrier transporting substance are dispersed in a binder. FIG. 7 shows a structure in which an intermediate layer 5 is provided between the photosensitive layer 4 having the layer structure shown in FIG. 6 and the conductive support 1 to effectively prevent injection of free electrons into the conductive support 1. It is. The intermediate layer 5 may be made of a polymer as described above as the binder resin, an organic polymer material such as polyvinyl alcohol, ethyl cellulose, or carboxymethyl cellulose, or aluminum oxide. 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. When forming the photosensitive layer having the above structure, the carrier generation layer 2 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 medium 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. Solvents or dispersion media used to form the carrier generation layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, and toluene. , xylene, chloroform,
Examples include 1,2-dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, and dimethyl sulfoxide. When a binder is used to form a carrier generation layer or a carrier transport layer, any binder can be used, but in particular, polymers that are hydrophobic, have a high dielectric constant, and have the ability to form an electrically insulating film are used. Polymers are 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 l Vinyl chloride -Vinyl acetate-maleic anhydride copolymer m Silicone resin n Silicone-alkyd resin o Phenol-formaldehyde resin p Styrene-alkyd resin q Poly-N-vinylcarbazole r Polyvinyl butyral These binders may be used alone or in combination of two or more Can be used as a mixture. In the carrier generation layer of the photoreceptor according to the present invention, a carrier generation substance is used as a binder substance,
Carrier generating substance/binder substance = 5-150%
(i.e. 5 to 150 parts by weight per 100 parts by weight of binder material)
If the content is within a specific range (preferably 10 to 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 carrier generating substance is small, the photosensitivity will be poor and the residual potential will increase, and if it is too large, the acceptance potential will drop a lot and the memory will tend to increase. In addition, the content of carrier transport substance in the carrier generation layer is also important; carrier transport substance/binder substance = 20
~200% (i.e. for 100 parts by weight of binder material)
(20 to 200 parts by weight, preferably 50 to 120 parts by weight); within this range, the residual potential is low and the photosensitivity is good, and the solvent solubility of the carrier transport substance is also maintained well. Outside this range, if the carrier transport substance is small, the residual potential and photosensitivity tend to deteriorate, resulting in poor images, white spots, blurring, etc., and if it is too large, solvent solubility tends to deteriorate.
The film strength tends to be low. The carrier transport material content range may be the same in the carrier transport layer. In addition, the ratio of the carrier-generating substance and the carrier-transporting substance in the carrier-generating layer is such that the weight ratio of the carrier-generating substance to the carrier-transporting substance is (1:0.2) in order to effectively exhibit the respective functions of both substances. ~(1:10) is preferable,
(1:0.5) to (1:7) are even better. If the proportion of the carrier-generating substance is smaller than this range, sensitivity 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 carrier generation layer 2 is 0.6
It is preferably 1 to 10 μm, more preferably 1 to 8 μm. If this thickness is less than 0.6 μm, the surface of the carrier generation layer will be mechanically damaged during repeated use due to usage conditions such as development and cleaning, resulting in part of the layer being scraped off or black streaks appearing on the image. Sometimes it appears. Further, if the diameter is less than 0.6 μm, the sensitivity tends to be insufficient.
However, if the thickness of the carrier generation layer exceeds 10μm,
As the number of thermally excited carriers generated increases and the environmental temperature rises, the acceptance potential decreases, memory phenomena increase, and image density tends to decrease. Furthermore, when irradiating light with a wavelength longer than the absorption edge of the carrier-generating substance, optical carriers 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, during repeated use, the residual potential tends to increase. Further, the thickness of the carrier transport layer 3 is 5 to 50 μm,
Preferably it is 5 to 30 μm. If this thickness is less than 5 μm, the charging potential will be small because it is thin.
Moreover, if the thickness exceeds 50 μm, the residual potential tends to increase. Further, it is desirable that the film thickness ratio between the carrier generation layer and the carrier transport layer is 1:(1 to 30). When the photosensitive layer is formed by dispersing the carrier-generating substance, the carrier-generating substance is 5 μm or less and 0.1 μm or more, preferably 2 μm or less.
It is preferable that the powder has an average particle size of 0.2 μm or more. That is, 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, electrical discharge may occur at the protruding parts of the particles, or Toner particles tend to adhere there, causing a toner filming phenomenon. Long wavelength light (~700nm) as a carrier generating substance
It is thought that the surface charge of those sensitive to carriers is neutralized by the generation of thermally excited carriers in the carrier-generating substance, and the larger the particle size of the carrier-generating substance, the greater this neutralizing effect. Therefore, high resistance and high sensitivity can only be achieved by reducing the particle size. However, if the above particle size is too small, it will tend to aggregate and the resistance of the layer will increase.
The number of crystal defects increases, resulting in a decrease in sensitivity and repeatability, as well as a decrease in charging ability. Further, since there is a limit to miniaturization, 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-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile, picryl chloride, quinone chlorimide, chloranil, brumanil, dichlorodicyanoparabenzoquinone , anthraquinone,
Dinitroanthraquinone, 9-fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene-[dicyanomethylenemalonodinitrile], picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid , pentafluorobenzoic acid, 5-nitrosalicylic 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 a weight ratio of 100:0.01~
200, preferably 100:0.1-100. The support 1 on which the photosensitive layer is to be provided is a metal plate, a metal drum, a conductive polymer, a conductive compound such as indium oxide, aluminum,
A conductive thin layer made of a metal such as palladium or gold is formed on a substrate such as paper or plastic film by coating, vapor deposition, laminating, or the like. As the intermediate layer functioning as an adhesive layer or barrier layer, a material 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 is used. It will be done. The photoreceptor for electrophotography based on the present invention can be obtained as described above, and its feature is that when the maximum value of the photosensitive wavelength range of the metal-free phthalocyanine used in the present invention exists in the range of 770 nm or more and less than 790 nm, the photoreceptor for semiconductor lasers is As mentioned above, this metal-free phthalocyanine is extremely stable in crystal form, and transition to other crystal forms is unlikely to occur. This is a great advantage not only in the production and properties of the metal-free phthalocyanine of the present invention described above, but also in the production and use of electrophotographic photoreceptors. E. Examples Hereinafter, the present invention will be described in more 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 synthesis example of 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. The dried powder was extracted with acetone in a 24-hour continuous extractor and dried in air to a blue powder. In the above, the precipitation was repeated to ensure a salt residue for lithium. In this way
30.5 g of blue powder was 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-phthalocyanine compound obtained in this way was placed in a 900 ml porcelain ball mill half-filled with 13/16-inch diameter balls, and milled at approximately 80 rpm for 164 hours. Metal phthalocyanine compound A was obtained. This compound exhibited the X-ray diffraction spectrum shown in FIG. <Synthesis Example 2> The metal-free phthalocyanine of Synthesis Example 1 was dissolved in an organic solvent such as tetrahydrofuran or 1,2-dichloroethane.
200ml was added into the ball mill and milled again for 24 hours. The organic solvent was removed from the dispersion after milling and the dispersion was dried to obtain 28.2 g of metal-free phthalocyanine compound B. This compound exhibited the X-ray diffraction spectrum shown in FIG. <Synthesis Example 3> An α-type metal-free phthalocyanine compound (Monolite Fast Bull 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 this solution was poured into ice water to cause reprecipitation, thereby transforming it into the α-type. This reprecipitate was washed with aqueous ammonia, methanol, etc., and then dried at 10°C. Next, α purified as above
The type-free metal phthalocyanine compound was placed in a sand mill with a grinding aid and a dispersant, and the temperature was 100±20℃.
The mixture was kneaded for 15 to 25 hours. After confirming that the crystal form has transitioned to τ type by this operation, remove it from the container,
After thoroughly removing the grinding aid and dispersant with water, methanol, etc., the product was dried to obtain clear blue crystals of τ-type metal-free phthalocyanine. This phthalocyanine showed the X-ray diffraction spectrum shown in FIG. Examples 1 to 11, Comparative Example 1 A vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslec MF-10" (manufactured by Sekisui Chemical Co., Ltd.) was coated on a conductive support made of a polyester film laminated with aluminum foil. Consisting of thickness
An intermediate layer of 0.05 μm was formed. Next, the carrier transport substance shown in FIG. 8 and a binder resin (polycarbonate: Panlite L1250) were mixed in a 1,2-
A solution in 67 ml of dichloroethane was applied onto the intermediate layer to form a carrier transport layer. Next, a dispersion obtained by adding each carrier generating substance having an average particle size of 1 μm shown in FIG. 8, each carrier transporting substance, and a binder resin to 67 ml of 1,2-dichloroethane and dispersing them in a ball mill for 12 hours was prepared as described above. A carrier generation layer was formed by coating and drying on the carrier transport layer, and each electrophotographic photoreceptor was manufactured. The electrophotographic photoreceptor obtained in this way was mounted on an electrostatic tester "EPA-8100 model" (manufactured by Kawaguchi Electric Seisakusho).
The following characteristic tests were conducted. In other words, + to the charger
After applying a voltage of 6 kV and charging the photosensitive layer by corona discharge for 5 seconds, the photosensitive layer was left to stand for 5 seconds, and then a 780 nm spectrometer was applied to the surface of the photosensitive layer.
The exposure amount required to attenuate the surface potential of the photosensitive layer by half by irradiating it with light, that is, the half-reduction exposure amount E1/
I asked for 2. In addition, the acceptance potential V _A when charged by the above corona discharge and the residual potential after 10 lux sec exposure
Values for V _R were measured. In addition, a photoreceptor layer similar to that shown in the example was used.
It was formed on an Al drum, mounted on a modified laser beam printer LP-3010 (manufactured by Konishiroku Photo Industry Co., Ltd.) (using a semiconductor laser light source), and image evaluation was performed (CD is image density, R is resolution). ◎: Density is sufficiently high and resolution is also very good. (CD≧1.2, R≧6.0) ○: Both density and resolution are good. (1.2>CD≧0.7, 6.0>R≧4.0) ×: The density is low and the resolution is not sufficient. Additionally, fogging and white or black spots appear. In addition, CD is Sakura Densitometer (Model PDA-
65: Measured with Konishiroku Photo Industry Co., Ltd.), R is Sakura Densitometer (Model PDM-5: Konishiroku Photo Industry Co., Ltd.)
Measured at For both CD and R, the density of white paper was set to 0.0, and the reflection density was measured and evaluated. However, the specific method for measuring R was as follows. That is, the resolution chart is measured using a microdensitometer with a slit of 500μ x 20μ. The judgment criteria for the resolution chart is the following formula: 30
Judgment is made from the resolution chart with a response of % or more. If the density of the image area of the copied image is D ^copy _nax , the density of the non-image area is D ^copy _nio , the density of the image area of the original document _is ^Dorig _nax , and the density of the non-image area is Dorig ^nio , then D ^copy / _nax −D ^copy ／ _nio ／D ^copy ／ _nax ＋D ^copy ／ _nio ／
D ^orig / _nax −D ^orig / _nio /D ^orig / _nax +D ^orig / _nio ≧30
(%) According to this result, Examples 1 to 1 based on the present invention
It can be seen that all of the 11 samples exhibit considerably better electrophotographic characteristics than Comparative Example 1. In particular, the use of metal-free phthalocyanine B of the present invention as a CGM and the use of a carrier generating layer.
Adding CTM greatly affects the characteristics of the photoconductor, and can achieve remarkable results as a positive charging photoconductor, such as improving high charging potential and its stability, and greatly improving photosensitivity. . In addition, tests using semiconductor lasers revealed that high density and high resolution were obtained, and long wavelength sensitivity was improved.

[Brief explanation of drawings]

1 to 8 are for explaining the present invention, and FIGS. 1 and 3 are X-ray diffraction spectra of two examples of metal-free phthalocyanine, and FIGS.
The figures are infrared absorption spectra of two examples of metal-free phthalocyanine, Figure 5 is near-infrared spectrum of metal-free phthalocyanine, and Figures 6 and 7 are cross-sectional views of two examples of electrophotographic photoreceptors. , FIG. 8 is a diagram showing a comparison of changes in characteristics depending on the composition of each electrophotographic photoreceptor. FIG. 9 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... carrier generation layer, 3... carrier transport layer, 4... photosensitive layer, 5... intermediate layer.

Claims (1)

[Scope of Claims] 1. A photoreceptor in which a carrier transport layer containing a carrier transport substance and a binder substance and a carrier generation layer containing a carrier generation substance and a binder substance are laminated in this order, with a Cu Kα of 1.541 Å. Black angle 2θ with respect to X-rays
(However, the error is 2θ ± 0.2 degrees) is 7.7 degrees, 9.3 degrees, 16.9 degrees
It has an X-ray crystal diffraction spectrum with main peaks at 17.5 degrees, 22.4 degrees, and 28.8 degrees, and the peak intensity ratio of the peak at the black angle of 16.9 degrees to the peak at the above black angle of this X-ray diffraction spectrum is 0.8 to 1.0.
and the intensity of each peak at the black angle of 22.4 degrees and 28.8 degrees with respect to the peak at the black angle of 9.3 degrees is 0.4 or more, and 700 ~
It has an infrared absorption spectrum with peaks at 760 cm ^-1 , 1320 ± 2 cm ^-1 and 3288 ± 3 cm ^-1 , and
A photoreceptor characterized by having four peaks in the absorption band at 760 cm ^-1 , of which 752±2 cm ^-1 contains the strongest metal-free phthalocyanine.