JPH03181950A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having a sufficiently high sensitivity in a semiconductor laser oscillation wavelength region by adequately combining and using an oxytitanium phthalocyanine crystal and biphenyl compd. which are respectively specific. CONSTITUTION:The oxytitanium phthalocyanine crystal, with which the Bragg angle 2theta+ or -0.2 deg. at the X-ray diffraction spectra using CuKalpha characteristic X-rays has major peaks at 9.0 deg., 14.2 deg., 23.9 deg. and 27.1 deg., and the biphenyl compd. expressed by formula I are incorporated into the photosensitive body. In the formula I, R<1>, R<2> denote a hydrogen atom, alkyl group or alkoxy group; R<3>, R<4> denote an alkyl group, aralkyl group, alkoxy group, hydroxyl group, or halogen atom. The electrophotographic sensitive body having the sufficiently high sensitivity in the semiconductor laser oscillation wavelength region is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor used in copying machines, printers, and the like.

[Prior Art] Conventionally, inorganic photoreceptors having a photosensitive layer containing selenium, cadmium sulfide, zinc oxide, etc. as main components have been widely used as electrophotographic photoreceptors. These are not necessarily satisfactory in terms of thermal stability, moisture resistance, durability, etc.
In particular, selenium and cadmium sulfide have limitations in production and handling due to their toxicity. On the other hand, organic photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component have many advantages such as overcoming the above-mentioned drawbacks of inorganic photoreceptors, and have attracted attention in recent years.

Such organic photoreceptors include photoconductive polymers typified by poly-N-vinylcarbazole and 2.
Electrophotographic photoreceptors having a photosensitive layer containing as a main component a charge transfer complex formed from a Lewis acid such as 4,7-h dinitro-9-fluorothone have already been put to practical use. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability.

On the other hand, a functionally separated electrophotographic photoreceptor in which the charge generation function and the charge transport function are performed by separate substances has brought about significant improvements in sensitivity and durability, which have been considered to be shortcomings of conventional organic photoreceptors. Such a functionally separated photoreceptor has the advantage that a charge generating material and a charge transporting material can be selected from a wide range, and an electrophotographic photoreceptor having arbitrary characteristics can be produced relatively easily.

In recent years, electrophotographic photoreceptors have been rapidly used not only in copying machines but also in non-impact printers that apply electrophotographic technology. These are laser beam printers that mainly use laser light as a light source, and a semiconductor laser is used as the light source in view of cost and device size.

Semiconductor lasers that are currently mainly used have a long oscillation wavelength of 790±20 nm, and efforts have been made to develop electrophotographic photoreceptors that have sufficient sensitivity to light at these long wavelengths. Sensitivity on the long wavelength side varies depending on the type of charge-generating substance contained in the electrophotographic photoreceptor, and many charge-generating substances have been studied. Typical charge generating substances include phthalocyanine pigments, azo pigments, cyanine dyes, azulene dyes, and squarylium dyes.

On the other hand, in recent years, research has been conducted on metal phthalocyanines or metal-free phthalocyanines, such as aluminum lolphthalocyanine, chloroindium phthalocyanine, oxyvanadyl phthalocyanine, chlorogallium phthalocyanine, magnesium phthalocyanine, and oxytitanium phthalocyanine, as charge-generating substances that are sensitive to long wavelength light. Many things have been done.

Among these, many phthalocyanine compounds are known to have polymorphisms; for example, metal-free phthalocyanine has an α-type,
There are β-type, γ-type, δ-type, δ-type, χ-type, τ-type, etc. Among copper phthalocyanines, α-type, β-type, γ-type, δ-type, δ-type, χ-type, etc. are generally known.

It is also generally known that the differences in these crystal forms have a large effect on electrophotographic properties (sensitivity, potential stability during durability, etc.) and coating properties when made into a coating.

Oxytitanium phthalocyanine, which is particularly sensitive to long-wavelength light, has polymorphisms as well as other phthalocyanines, such as the above-mentioned metal-free phthalocyanine and copper phthalocyanine. For example, JP-A-59-49544
Publication No. (USP4゜444.861), JP-A-59-1
No. 86959, Japanese Patent Application Laid-open No. 61-239248 (
USP4.728.592), Japanese Patent Publication No. 62-67094
Publication No. (USP4,664,997), JP-A-63-3
66, JP 63-116158, JP 83-198067, and JP 64-1706.
No. 6 reports oxytitanium phthalocyanine having different crystal forms.

[Problems to be solved by the invention] However, these oxytitanium phthalocyanines,
There are some practical problems such as insufficient sensitivity, poor potential stability during repeated use, poor charging ability, and image deterioration due to changes in the usage environment, but I am still fully satisfied. I'm not getting what I want.

Additionally, in general, in electrophotographic photoreceptors, a charge transporting material that is effective against a particular charge-generating substance is not necessarily effective against other charge-generating materials; A charge-generating substance that is effective against other charge-transporting substances may not necessarily be effective against other charge-transporting substances. That is, there is always an appropriate combination of charge generating substances and charge transporting substances that receive and transfer charges. An inappropriate combination will cause many problems such as decreased sensitivity and increased residual potential, worsened potential stability during repeated use, and decreased charging ability.

Therefore, the combination of a charge-generating substance and a charge-transporting substance is extremely important, but there are no general rules regarding this combination, and it is quite difficult to find a charge-transporting substance that is compatible with a specific charge-generating substance. It becomes.

A first object of the present invention is to provide an electrophotographic photoreceptor having sufficiently high sensitivity in the semiconductor laser oscillation wavelength range.

A second object of the present invention is to provide an electrophotographic photoreceptor that maintains a stable potential during repeated use and exhibits stable potential characteristics and image characteristics regardless of the usage environment (temperature, humidity).

[Means for Solving the Problems] The present invention has been made to achieve the above-mentioned object, and more specifically, the Bragg angle 2θ±02° in the CuKα characteristic X-ray diffraction spectrum is 9.0′. ″, 142
° 23.9' An oxytitanium phthalocyanine crystal having a main peak at 271° and at least one type of the following general formula [I] [wherein RI R2 is a hydrogen atom, an alkyl group,
or represents an alkoxy group, R3 and R4 are alkyl groups,
Indicates an aralkyl group, an alkoxy group, a hydroxyl group, or a halogen atom. ] An electrophotographic photoreceptor characterized by containing a biphenyl compound represented by the following.

In the above general formula [1], when R1 and R2 are an alkyl group, specific examples include methyl, ethyl, propyl, etc., and when they are an alkoxy group, examples include methoxy, ethoxy, etc. Examples of R3 and R4 include, in addition to the alkyl and alkoxy groups described above, aralkyl groups such as benzyl and phenethyl, and halogen atoms such as chlorine, bromine, and iodine.

In the above general formula [1], it is preferable that either one of RI R2 is a hydrogen atom, and the other and R3R4 are each an alkyl group such as methyl, ethyl, propyl, or an alkoxy group such as methoxy or ethoxy. Among these, methyl and ethyl are preferred as the alkyl group, and methoxy and ethoxy are preferred as the alkoxy group.

The X-ray diffraction pattern of the oxytitanium phthalocyanine crystal in the present invention has a Bragg angle (2θ±0°2°) of 9.0° as shown in FIGS. 1, 2, and 3.
Major peaks are shown at positions 142°, 23.9° and 27.1°. The above peaks correspond to the top four points with the highest peak intensities.

As for the characteristics in the X-ray diffraction diagrams of FIGS. 1, 2, and 3, among the four peaks mentioned above, the peak at 271° is the strongest, and the peak at 9.0' is the second strongest. Also, 1
There is a peak weaker than the above four points at the position of 7.9°, and an even weaker peak at the position of 13.3°. Also, 10.5° ~ 1
3.0°14.8°~17.4° and 18.2°~2
There are virtually no peaks in the 32° range.

In addition. In the present invention, the peak shape of X-ray diffraction may vary due to differences in manufacturing conditions, measurement conditions, etc.
There may be a slight difference, for example, the tip of each peak may be split. In the case of Figure 1, 8.9
The peak of 14.2''' can be seen at around 9.4°, and another split peak of 14.1° can be seen.

The structure of the oxytitanium phthalocyanine crystal used in the present invention is generally expressed as follows. However, Xl, x2, x, I%x4 are C
It represents a corner or Br, and n, m, It, and k are integers from O to 4.

Next, typical examples of biphenyl compounds used in the present invention are listed below.

The combination of the charge generating substance of oxytitanium phthalocyanine crystal and the charge transporting substance of biphenyl compound used in the electrophotographic photoreceptor of the present invention is probably due to matching of the ionization potential of the charge generating substance and the charge transporting substance or to a steric type. For these reasons, charge injection from the charge-generating substance to the charge-transporting substance is carried out smoothly.
It is believed that it provides electrophotographic properties such as good sensitivity, low residual potential, and excellent potential stability during repeated use.

The method for producing oxytitanium phthalocyanine crystals used in the present invention will be exemplified below.

First, for example, titanium tetrachloride and orthophthalodinitrile are reacted in α-chloronaphthalene to obtain dichlorotitanium phthalocyanine. This was washed with a solvent such as α-chloronaphthalene, trichlorobenzene, dichlorobenzene, N-methylpyrrolidone, NN'-dimethylformamide, etc., and then washed with a solvent such as methanol, ethanol, etc.4, and then hydrolyzed with hot water. to obtain oxytitanium phthalocyanine crystals. The crystals thus obtained are often a mixture of various polymorphs, and it is usually difficult to obtain the oxytitanium phthalocyanine crystals used in the present invention even if this mixture is processed. Therefore, in the present invention, the thus obtained crystals are first converted into amorphous oxytitanium phthalocyanine by dissolving them in an acid and then reprecipitating them in water (acid basting method).

The obtained amorphous oxytitanium phthalocyanine is treated with methanol at room temperature and under heating or boiling for 30 minutes or more, preferably 1 hour or more, and then dried under reduced pressure to give n-propyl ether, n-butyl ether, 1so.
- Ether solvents such as butyl ether, 5ec-butyl ether, n-alkyl ether, n-butyl methyl ether, n-butyl ethyl ether, and ethylene glycol n-butyl ether, or monoterpene hydrocarbon solvents such as terpinolene and pinene, and liquid paraffin. Oxytitanium phthalocyanine crystals used in the present invention can be obtained by milling for 5 hours or more, preferably 10 hours or more using a solvent such as the following as a dispersion medium.

Note that the methanol treatment here refers to, for example, suspension stirring treatment of oxytitanium phthalocyanine in methanol. Further, the term "grilling treatment" refers to a treatment performed using a milling device such as a sand mill or a ball mill with a dispersion medium such as glass beads, steel beads, or alumina balls.

Hereinafter, an electrophotographic photoreceptor using an oxytitanium phthalocyanine crystal and a biphenyl compound of the present invention will be described.

First, a typical layer structure of an electrophotographic photoreceptor is shown in FIGS. 10 and 11. In the photoreceptor shown in FIG. Transport material (not shown)
, and is provided on the conductive support 3.

In the photoreceptor shown in FIG. 11, the photosensitive layer 1 is the charge generating layer 4.
It has a laminated structure of a charge transport layer 5 and a charge generation layer 4 containing a charge generation substance 2.

Note that the stacking relationship between the charge generation layer 4 and the charge transport layer 5 in FIG. 11 may be reversed.

When producing an electrophotographic photoreceptor, the conductive support 3 may be any material as long as it has conductivity, and examples include metals such as aluminum and stainless steel, metals with conductive layers, plastics, and paper. Examples include a cylindrical shape or a film shape.

Furthermore, a subbing layer having barrier and adhesive functions may be provided between the conductive support 3 and the photosensitive layer 1.

As the material for the undercoat layer, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, methyl cellulose, casein, boric acid, glue, gelatin, etc. are used.

These are dissolved in a suitable solvent and placed on a conductive support. is applied to. The film thickness is 0.2 to 3.0 μm.

A photosensitive layer consisting of a single layer as shown in FIG. 10 can be obtained by mixing the charge-generating substance of the oxytitanium phthalocyanine crystal and the charge-transporting substance of the biphenyl compound in a suitable binder resin solution, and then coating and drying the mixture. It will be done.

The charge generating layer of the photosensitive layer having a laminated structure as shown in FIG. 11 can be obtained by dispersing the oxytitanium phthalocyanine charge generating substance of the present invention together with a suitable binder resin solution, coating and drying. In this case, the binder resin may not be used.

Examples of binder resins include polyester resins, acrylic resins, polyvinyl carbazole resins, phenoxy resins, polycarbonate resins, polyvinyl butyral resins, polystyrene resins, polyvinyl acetate resins, polysulfone resins, polyarylate resins, and vinylidene chloride/acrylonitrile copolymers. Resin etc. are mainly used.

The charge transport layer is formed by applying and drying a paint in which a charge transport material, mainly a biphenyl compound, and a binder resin are dissolved in a solvent.

Moreover, as the binder resin, those mentioned above for the photosensitive layer consisting of a single layer can be used.

Coating methods for these photosensitive layers include dipping,
Spray coating method, spinner coating method,
A bead coating method, a blade coating method, a beam coating method, etc. can be used.

When the photosensitive layer 1 is a single layer, the blending ratio of the charge generating substance and the charge transporting substance in the photosensitive layer 1 is as follows:
2 to 20% by weight and 30 to 80% by weight, especially 2
-10% by weight and preferably 40-70% by weight. In addition, when the photosensitive layer 1 has a laminated structure, the charge generation material is 20 to 80% by weight, particularly 50 to 7% by weight, based on the charge generation layer 4.
The amount of the charge transport material is preferably 0% by weight, and the amount of the charge transport material is preferably 30 to 70% by weight, particularly 40 to 60% by weight, based on the charge transport layer 5.

When the photosensitive layer is a single layer, the appropriate film thickness is 5 to 40 μm, preferably 10 to 30 μm.

In addition, when the photosensitive layer has a laminated structure, the thickness of the charge generation layer is 000.
The thickness of the charge transport layer is 5 to 40 μm, preferably 10 to 5 μm.
The range is 30 μm.

Furthermore, in order to protect these photosensitive layers from external impact, a thin protective layer may be provided on the surface of the photosensitive layer.

In the electrophotographic photoreceptor of the present invention, when oxytitanium phthalocyanine crystal is used as a charge generating substance, it can be mixed with other charge generating substances or charge transporting substances depending on the purpose.

Such an electrophotographic photoreceptor can be widely applied not only to printers such as laser beam printers, LED printers, and CRT printers, but also to ordinary electrophotographic copiers and other electrophotographic application fields.

Next, an example of producing oxytitanium phthalocyanine crystals used in the present invention will be shown.

In 100 parts of α-chloronaphthalene, 5.0 g of 0-phthalodinitrile and 2.0 g of titanium tetrachloride were heated and stirred at 200°C for 3 hours, and then cooled to 50°C to precipitate crystals. After separation by filtration, a paste of dichlorotitanium phthalocyanine was obtained. Next, this was washed with 100 ml of N,N'-dimethylformamide heated to 100°C while stirring, and then
Washing was repeated twice with 100 ml of methanol at °C, followed by filtration. Furthermore, this obtained paste was diluted with 100% deionized water.
The mixture was stirred at 80° C. for 1 hour in M1 and filtered to obtain blue oxytitanium phthalocyanine crystals. Revenue! 4.3g.

The elemental analysis values of this compound were as follows.

1 Elemental analysis value (C32H+aN a T i O) CHN
C1 Calculated value (%) 66.68 2.80 19.44
0.00 Actual value (%) 61i, 50 2.9! l
I! 1,42 0.47 Next, add this crystal to 30 m of concentrated sulfuric acid.
1 and added dropwise to 300 ml of deionized water at 20° C. under stirring to cause reprecipitation, filtration, and thorough washing with water to obtain amorphous oxytitanium phthalocyanine. 4.0 g of the amorphous oxytitanium phthalocyanine thus obtained was added to 100 ml of methanol at room temperature (22°C).
The mixture was suspended and stirred for 8 hours, filtered, and dried under reduced pressure to obtain low-crystalline oxytitanium phthalocyanine. Next, 40 ml of n-butyl ether was added to 2.0 g of this oxytitanium phthalocyanine, and main ring treatment was performed at room temperature (22° C.) for 2 hours with glass beads of 1 mm diameter.

The solid content was taken out from this dispersion, thoroughly washed with methanol and then with water, and dried to obtain 2 oxytitanium phthalocyanine crystals used in the present invention. The yield was 1.8 g, and the X-ray diffraction pattern of this oxytitanium phthalocyanine crystal is shown in FIG. Further, a KBr pellet was prepared, and the infrared absorption spectrum of the oxytitanium phthalocyanine crystal was measured. The results are shown in FIG. In addition, the U
The results of the V absorption spectrum are shown in FIG.

50ml of pinene was added to 2.0g of methanol-treated oxytitanium phthalocyanine obtained in the same manner as in Production Example 1.
1 was added thereto, and milling was performed at room temperature (22° C.) for 20 hours using glass beads of 1 mm diameter. The solid content was taken out from this dispersion, thoroughly washed with methanol and then with water, and dried to obtain oxytitanium phthalocyanine crystals used in the present invention. The yield was 1.8 g. The X-ray diffraction pattern of this oxytitanium phthalocyanine crystal is shown in FIG.

Shake 10 Raw 1 3 100 ml of methanol was added to 4.0 g of amorphous oxytitanium phthalocyanine obtained in the same manner as in Production Example 1, and the mixture was boiled for 30 hours while stirring, then filtered and dried under reduced pressure. Oxytitanium phthalocyanine crystals were obtained. Yield: 3.6g. Next, this oxytitanium phthalocyanine 2. 60 ml of ethylene glycol n-butyl ether was added to Og, and milling was performed at room temperature (22° C.) for 15 hours using glass beads of 1 mm diameter.

The solid content was taken out from this dispersion, thoroughly washed with methanol and then with water, and dried to obtain oxytitanium phthalocyanine crystals used in the present invention. The yield was 1.8 g, and the X-ray diffraction pattern of this oxytitanium phthalocyanine crystal is shown in FIG.

Hi U dispatch 1yo.

Japanese Patent Application Publication No. 61-239248 (USP 4°728.
592), the so-called α
An oxytitanium phthalocyanine crystal called a type was obtained.

This oxytitanium phthalocyanine crystal X4 A line diffraction diagram is shown in FIG.

Japanese Patent Publication No. 62-67094 (USP 4,664.9)
According to the production example disclosed in 97), oxytitanium phthalocyanine crystals, so-called type A, were obtained.

The X-ray diffraction pattern of this oxytitanium phthalocyanine crystal is shown in FIG.

According to the production example disclosed in JP-A-64-17066, the same oxytitanium phthalocyanine crystals as in JP-A-64-17066 were obtained.

The X-ray diffraction pattern of this oxytitanium phthalocyanine crystal is shown in FIG.

In addition, the measurement of the X-ray diffraction pattern in the present invention was carried out under the following conditions using CuKα characteristic X-rays.

Measuring device used: Rigaku Denki X-ray diffraction device RAD-A system X-ray tube: Cu 5 Tube voltage: 50kV Tube current: 40mA Scan method: 2θ/θ scan Scan speed: 2deg/min.

Sampling interval: 0.020deg.

Start angle (2θ): 3deg.

Stop angle (2θ): 40deg.

Divergence slit: 0.5deg.

Scattering slit: 0.5 degrees Receiving slit: 0.3 mm Using a curved monochromator The electrophotographic photoreceptor of the present invention will be described in more detail below using Examples. In addition, "1 part" indicates a part by weight.

A subbing layer made of a vinyl chloride-maleic anhydride-vinyl acetate copolymer resin and having a film thickness of 0.1 μm was provided on a large 1041 aluminum plate.

Next, 4 parts of oxytitanium phthalocyanine crystals obtained in Production Example 1 and 2 parts of polyvinyl butyral resin were added to 100 parts of cyclohexanone and dispersed in a sand mill for 1 hour, followed by 100 parts of tetrahydrofuran. was added and diluted, and this was applied onto the undercoat layer so that the film thickness after drying was 0.3 μm to form a charge generation layer.

Further, 5 g of the above-mentioned biphenyl compound (D2) and 6 g of bisphenol 2 type polycarbonate resin (viscosity average molecular weight 30,000) were dissolved in 70 ml of chlorobenzene, and this was applied onto the charge generation layer so that the film thickness after drying was 18 μm. An electrophotographic photoreceptor (photoreceptor No. 1) was prepared by coating with a Mayer bar to form a charge transport layer.

An electrophotographic photoreceptor (comparative photoreceptor No. 1) was produced in the same manner as in Example 1, except that the α-type oxytitanium phthalocyanine crystal obtained in Comparative Production Example 1 was used.

An electrophotographic photoreceptor (comparative photoreceptor No. 2) was produced in the same manner as in Example 1, except that the A-type oxytitanium phthalocyanine crystal obtained in Comparative Production Example 2 was used.

Comparative Example 3 An electrophotographic photoreceptor (comparative photoreceptor N
o, 3) was produced.

The electrophotographic photoreceptors of Example 1 and Comparative Examples 1.2.3 were processed using a laser beam printer (product name: LBP-
3X: Paste it on the cylinder of a modified Canon machine and set the charge so that the dark area potential is -700 (V).
By irradiating this with a laser beam with a wavelength of 802 nm, -700
The amount of light required to lower the potential of (V) to -100 (V) was measured and defined as the sensitivity.

The results are shown in Table 1.

8 Table 1 Furthermore, electrophotographic photoreceptors were produced in the same manner as in Example 1 using the oxytitanium phthalocyanine crystals obtained in Production Example 2 and Production Example 3, respectively, and the sensitivity was measured. Similar C high sensitivity characteristics were obtained.

Next, these four types of photoreceptors were heated at a humidity of 10% and a temperature of 5°C.
Endurance for continuous paper feeding of 3,000 sheets in three environments: 50% humidity and 18°C, and 80% humidity and 35°C, with the dark area potential set to -700 (V) and the light area potential set to -100 (V), respectively. A test was conducted to evaluate the image after the durability test.

In the test using the photoreceptor of Example 1, good images equivalent to the initial image were obtained even after the durability test under any environment, but in the test using the photoreceptor of Comparative Example 1.2.3. In this case, under any environment), the white background part will suffer from brittleness, especially when the humidity is 80% and the temperature is 35℃.
It was remarkable under the following conditions, and it was most remarkable in the test using the photoreceptor of Comparative Example 3).

Therefore, in the test using the photoreceptor of Comparative Example 1.2.3,
In both cases, adjustments were made using the density adjustment lever to remove the soil power, but this time the density in the black areas was insufficient.

Incidentally, FIG. 9 shows the distribution of spectral sensitivity in the case where the maximum value of spectral sensitivity is 100 in the electrophotographic photoreceptor of Example 1.

In this way, the electrophotographic photoreceptor of the present invention has a molecular weight of 770 to 810.
It exhibits stable high sensitivity characteristics in the long wavelength region around nm.

Electrophotographic photoreceptors (photoreceptors No. 12 to io) were prepared in the same manner as in Example 1, except that the oxytitanium phthalocyanine crystals produced in Production Example 1 and the biphenyl compounds shown in Table 2 below were combined. did. Each of these photoconductors was subjected to a laser beam printer (product name: LBP-SX: manufactured by Canon) in the same manner as in Example 1.
When attached to the cylinder of a modified machine, the dark potential was -70
The charge was set to 0 (V), and the potential of -700 (V) was changed to -100 by irradiating it with 802 nm laser light.
The amount of light EΔ6oo required to lower the voltage to (V) was measured.

In addition, each of these photoreceptors was set to a dark potential of 700 (V).
After resetting the charging setting so that the bright area potential is -200 (V), a continuous paper feeding durability test of 5,000 sheets was conducted, and the variation amount ΔV of the dark area potential and bright area potential after 5,000 sheets of paper feeding with respect to the initial value was determined. , and ΔvL were measured. These results are shown in Table 2.

Table Comparison Electrophotographic photoreceptors (comparative photoreceptors No. 4 to 18) was prepared and evaluated in the same manner. The results are shown in Table 3.

Table 1 Examples 19-24 Compounds H-1 to H-6 having the following structures were used as charge transport substances instead of the biphenyl compounds used in Examples 2 to 10, respectively, in the same manner as in Examples 2 to 10. Electrophotographic photoreceptors (comparative photoreceptors Nos. 19 to 24) were prepared and evaluated in the same manner.

The results are shown in Table 4.

Table 4 From the results shown in Tables 2 to 4, the electrophotographic photoreceptor of the present invention comprising a combination of an oxyphthalocyanine with a specific crystal structure and a specific biphenyl compound has extremely excellent sensitivity and potential stability during repeated use. It can be seen that

East mff1ll± A subbing layer similar to that in Example 1 was formed using a bar code on an aluminum-based sheet substrate having a thickness of 50 μm, and a charge transport layer similar to that in Example 1 was further formed on this to a thickness of 20 μm. It was formed like this.

Next, 5 parts of bisphenol Z type polycarbonate were dissolved in 68 parts of cyclohexanone, and 3 parts of oxytitanium phthalocyanine showing the X-ray diffraction pattern obtained in Production Example 1 was mixed with this solution, and dispersed in a sand mill for 1 hour. Thereafter, 5 parts of bisphenol Z-type polycarbonate and 10 parts of the charge transport material used in Example 1 were dissolved, and 40 parts of tetrahydrofuran and 40 parts of dichloromethane were added for dilution to obtain a dispersion paint. This paint was applied onto the charge transport layer by a spray coating method and dried to form a charge generation layer having a thickness of 66 μm, thereby producing an electrophotographic photoreceptor (photoreceptor No. 11).

An electrophotographic photoreceptor (comparative photoreceptor N0825) was produced in the same manner as in Example 11, except that α-type oxytitanium phthalocyanine obtained in Comparative Production Example 1 was used as the charge generating substance.

Arashi Tate Plate Yu 1 An electrophotographic photoreceptor (comparative photoreceptor No. 26) was produced in the same manner as in Example 11, except that type A oxytitanium phthalocyanine obtained in Comparative Production Example 2 was used as the charge generating substance.

JP-A-64 obtained in Comparative Production Example 3 as a salt unicharge generating substance
An electrophotographic photoreceptor (comparative photoreceptor (No. 27)) was produced in the same manner as in Example 11, except that oxytitanium phthalocyanine having the same crystal form as No. 17066 was used.

Example 11 and Comparative Example 25.26.2 thus obtained
The electrophotographic photoreceptor No. 7 was evaluated using an electrostatic tester (E7 PA-8100, manufactured by Kawaguchi Denki).

First of all, the surface potential was 700 (from Positive Corona Charging Company).
V), and then exposed to monochromatic light of 802 nm separated by a monochromator, and the amount of light when the surface potential decreased to 200 (V) was measured and used as the sensitivity. The results are shown in Table 5.

Table 5 [Effects of the Invention] As described above, according to the present invention, by appropriately combining a specific oxytitanium phthalocyanine crystal and a specific biphenyl compound, it is possible to achieve high sensitivity in the semiconductor laser oscillation wavelength range. has (2
) exhibits stable image characteristics in the electrophotographic process,
(3) An electrophotographic photoreceptor with excellent potential stability can be provided.

[Brief explanation of drawings]

Figures 1, 2, and 3 are Manufacturing Example 1.2, respectively.
The X-ray diffraction patterns, FIGS. 4, 5, and 6 of the oxytitanium phthalocyanine crystals of the present invention obtained in Comparative Production Examples 1.2 and 3 are respectively X-ray diffraction diagram, Figure 7 is an infrared absorption spectrum diagram (KBr tablet method) of the oxytitanium phthalocyanine crystal of the present invention, Figure 8 is a UV absorption spectrum diagram of the oxytitanium phthalocyanine crystal of the present invention, and Figure 9 is an infrared absorption spectrum diagram of the oxytitanium phthalocyanine crystal of the present invention. The spectral sensitivity characteristic diagram of the electrophotographic photoreceptor of Example 1, FIGS. 10 and 11 are schematic cross-sectional views of the layer structure of the electrophotographic photoreceptor. 1: Photosensitive layer 2: Charge generating substance 3: Conductive support 9: Charge generating layer/charge transport layer. 0

Claims (1)

[Claims] 1. The Bragg angle 2θ±0.2° in the X-ray diffraction spectrum using CuKα characteristic X-rays is 9.0°14.2°,
There is an oxytitanium phthalocyanine crystal with main peaks at 23.9° and 27.1°, and at least one of the following general formulas [I]▲Mathematical formulas, chemical formulas, tables, etc.▼[
I] [In the formula, R^1 and R^2 represent a hydrogen atom, an alkyl group, or an alkoxy group, and R^5 and R^4 represent an alkyl group, an aralkyl group, an alkoxy group, a hydroxyl group, or a halogen atom. . ] An electrophotographic photoreceptor comprising a biphenyl compound represented by the following. 2. In the general formula [I], one of R^1 and R^2 is a hydrogen atom, and the other and R^3 and R^4
The electrophotographic photoreceptor according to claim 1, wherein each is an alkyl group or an alkoxy group.