JP3005052B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photosensitive member containing a specific oxytitanium phthalocyanine and a metal-free phthalocyanine in a photosensitive layer.

[0002]

2. Description of the Related Art In recent years, as a printer for a terminal, an impact-type printer to which electrophotographic technology is applied has been widely used instead of a conventional impact-type printer. These are laser beam printers that mainly use laser light as a light source, and a semiconductor laser is often used as the light source in terms of cost, size of the apparatus, and the like.

At present, semiconductor lasers mainly used have an oscillation wavelength of 790 ± 20 nm, which is relatively long, and therefore, development of an electrophotographic photoreceptor having sufficient sensitivity to such long-wavelength light is progressing. Have been.

[0004] Sensitivity mainly depends on the type of charge generating substance, and many charge generating substances have been studied.

Typical charge generating substances include phthalocyanine pigments, azo pigments, cyanine dyes, azulene dyes, and squarium dyes.

Among these, recently, as charge generating substances having good sensitivity to long wavelength light, metals such as aluminum chlorophthalocyanine, chloroindium phthalocyanine, oxyvanadium phthalocyanine, chlorogallium phthalocyanine, magnesium phthalocyanine and oxytitanium phthalocyanine have been recently used. Many studies have been made on phthalocyanines or metal-free phthalocyanines.

Among them, many phthalocyanine compounds are known to exist in many crystal forms. For example, metal-free phthalocyanines include α-type, β-type, γ-type, δ-type, ε-type, χ-type and τ-type. For copper phthalocyanine, α-form, β
Type, γ type, δ type, η type, and χ type.

It is also generally known that the crystal type greatly affects the electrophotographic characteristics (sensitivity, potential stability at the time of durability, etc.) and the characteristics of the paint when formed into a paint.

As described above, there are many crystals of oxytitanium phthalocyanine, such as metal-free phthalocyanine and copper phthalocyanine, like other phthalocyanines. For example, JP-A-59-49544 (USP)
4,444,861), JP-A-59-166959 and JP-A-61-239248 (US Pat.
8,592), JP-A-62-67094 (USP)
4,664,997), JP-A-63-366, JP-A-63-116158, and JP-A-63-1980.
Oxytitanium phthalocyanine having a different crystal form is reported in, for example, JP-A-67-170 and JP-A-64-17066.

Oxytitanium phthalocyanine is a material having excellent electrophotographic properties, but further improvement in dispersion stability, sensitivity and image quality is desired.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor which has good dispersion stability of a coating solution for a photosensitive layer, has high sensitivity, and can obtain a high quality image. .

[0012]

That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer has a Bragg angle (2) in CuKα characteristic X-ray diffraction.
oxytitanium phthalocyanine having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 °, or the Bragg angle (2θ ± 0.2) in characteristic X-ray diffraction of CuKα. °) is 7.4 °, 9.2 °, 1
0.4 °, 11.6 °, 13.0 °, 14.3 °, 1
5.0 °, 15.5 °, 23.4 °, 24.1 °, 2
An electrophotographic photoreceptor containing oxytitanium phthalocyanine having strong peaks at 6.2 ° and 27.2 ° and containing metal-free phthalocyanine.

The structure of the oxytitanium phthalocyanine used in the present invention is as follows:

[0014]

[Outside]

Is represented by

Wherein X ¹ , X ² , X ³ and X ⁴ represent Cl or Br, and n, m, l and k are integers of 0-4.

As described above, oxytitanium phthalocyanine exists in various crystal forms. As a result of intensive studies, the present inventor has found that the dispersion stability of the photosensitive layer coating solution is improved by adding oxytitanium phthalocyanine and metal-free phthalocyanine of a specific crystal form to the photosensitive layer coating solution. Accordingly, an electrophotographic photosensitive member having high sensitivity and capable of obtaining a good image could be provided.

The metal-free phthalocyanine used in the present invention is not particularly limited, but its addition amount is preferably from 0.1 to 30% by weight, particularly preferably from 1.0 to 10% by weight, based on oxytitanium phthalocyanine.

Next, a synthesis example of the oxytitanium phthalocyanine crystal used in the present invention will be described.

Hereinafter, parts are parts by weight.

Synthesis Example 1 5.0 g of o-phthalodinitrile and 2.0 g of titanium tetrachloride were heated and stirred at 200 ° C. for 3 hours in 100 g of α-chloronaphthalene, and then cooled to 50 ° C. to precipitate. The crystals were separated by filtration to obtain a paste of dichlorotitanium phthalocyanine. Next, this was washed with stirring with 100 ml of N, N'-dimethylformamide heated to 100 ° C.
Washing was repeated twice with 100 ml of methanol at 0 ° C., followed by filtration. Further, the obtained paste is mixed with deionized water 1
The mixture was stirred at 00 ° C. for 1 hour in 00 ml and filtered to obtain a blue oxytitanium phthalocyanine crystal. Yield 4.3 g.

The elemental analysis values of this compound were as follows. Elemental analysis _{(C 32 H 16 N 8 OTi} )

[0022]

【table】

Next, the crystals were dissolved in 150 g of concentrated sulfuric acid, dropped into 1500 ml of deionized water at 20 ° C. with stirring to reprecipitate, filtered and sufficiently washed with water to obtain amorphous oxytitanium phthalocyanine. 4.0 g of the amorphous oxytitanium phthalocyanine thus obtained was suspended and stirred in 100 ml of methanol at room temperature (22 ° C.) for 8 hours, filtered and dried under reduced pressure to obtain a low-crystalline oxytitanium phthalocyanine. I got Next, 40 ml of n-butyl ether was added to 2.0 g of the oxytitanium phthalocyanine, and milling was performed at room temperature (22 ° C.) for 20 hours together with 1 mmφ glass beads.

The solid content was removed from the dispersion, washed thoroughly with methanol and then with water, and dried to obtain the novel crystalline oxytitanium phthalocyanine of the present invention. Yield 1.8 g. FIG. 1 shows an X-ray diffraction diagram of this oxytitanium phthalocyanine. As can be seen from FIG. 1, this oxytitanium phthalocyanine has a Bragg angle (2θ ±
0.2 °) has strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 °.

(Synthesis Example 2) Blue oxytitanium phthalocyanine was obtained in the same manner as in Synthesis Example 1.

Next, the crystals are dissolved in 30 parts of concentrated sulfuric acid.
The solution was reprecipitated by dropping into 300 parts of deionized water at 20 ° C. with stirring to obtain amorphous oxytitanium phthalocyanine. To 10 parts of the amorphous oxytitanium phthalocyanine thus obtained, 15 parts of sodium chloride and 7 parts of diethylene glycol were mixed, and the mixture was milled in an automatic mortar under heating at 80 ° C. for 60 hours. Next, the treated product was washed sufficiently with water to completely remove sodium chloride and diethylene glycol. After drying under reduced pressure, 200 parts of cyclohexanone and glass beads having a diameter of 1 mm were added, and the mixture was treated by a sand mill for 30 minutes to obtain an oxytitanium phthalocyanine crystal of the present invention. FIG. 2 shows an X-ray diffraction diagram of the oxytitanium phthalocyanine crystal. As can be seen from FIG. 2, this oxytitanium phthalocyanine has a Bragg angle (2θ ± 0.2 °) of 7.4 °, 9.2 °,
0.4 °, 11.6 °, 13.0 °, 14.3 °, 1
5.0 °, 15.5 ° 23.4 °, 24.1 °, 26.
It has strong peaks at 2 ° and 27.2 °.

The measurement of the X-ray diffraction pattern in the present invention was carried out using CuKα radiation under the following conditions. Measuring instrument used: X-ray diffractometer manufactured by Rigaku Denki X-ray bulb: Cu Voltage: 50 kV Current: 40 mA Scanning method: 2θ / θ scan Sampling interval: 0.020 deg. Start angle (2θ): 3 deg. Stop angle (2θ): 40 deg. Divergence slit: 0.5 deg. Scattering slit: 0.5 deg. Receiving slit: 0.3mm curved monochromator used

Next, a typical layer structure of the electrophotographic photosensitive member of the present invention will be described with reference to FIGS.

FIG. 3 shows that the tourist layer 1 is composed of a single layer, and the photosensitive layer 1 simultaneously contains a charge generating substance 2 and a charge transporting substance (not shown).

Reference numeral 3 denotes a conductive support.

FIG. 4 shows that the photosensitive layer 1 has a laminated structure of the charge generation layer 4 and the charge transport layer 5, and the charge generation layer 4 contains the charge generation substance 2.

The charge generation layer 4 and the charge transport layer 5 shown in FIG.
May be upside down.

When producing the electrophotographic photosensitive member of the present invention,
The conductive support 3 may be any conductive material, and may be a metal such as aluminum, an aluminum alloy or stainless steel, or an inherently conductive plastic or paper provided with a conductive layer. Shape or film shape.

Further, an undercoat layer having both a barrier function and an adhesive function can be provided between the conductive support 3 and the photosensitive layer 1.

As a material for the undercoat layer, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, methyl cellulose, casein, polyamide, glue, gelatin and the like are used.

These are usually dissolved in a suitable solvent and applied on a conductive support. Its film thickness is 0.2 ~
3.0 μm.

The photosensitive layer 1 consisting of a single layer as shown in FIG.
Is formed, the oxytitanium phthalocyanine of the present invention and a charge transport material (not shown) are used as the charge generation material 2.
Is mixed with a liquid material of an appropriate binder resin described later, for example, a solution, and then dried by coating.

As a method for forming the charge generating layer 4 of the photosensitive layer 1 having a laminated structure of the charge generating layer 4 and the charge transporting layer 5 as shown in FIG. 4, the oxytitanium phthalocyanine charge generating material of the present invention is suitably used. It is obtained by dispersing together with a binder resin solution, coating and drying the surface of the conductive support 3. In this case, the binder resin may not be provided.

As the binder resin used herein, for example, polyester resin, acrylic resin, polyvinyl carbazole resin, phenoxy resin, polycarbonate resin, polyvinyl butyral resin, polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, vinylidene chloride Acrylonitrile copolymer resin is mainly used.

The charge transport layer is formed by coating and drying a coating material in which a charge transport material and a binder resin are dissolved in a solvent.

Examples of the charge transporting material used include various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds.

As the binder resin, those described above can be used.

As a method of applying these photosensitive layers, dipping, spray coating, spinner coating, bead coating, blade coating, beam coating, and the like can be used.

When the photosensitive layer is a single layer, the thickness is 5 to 40 μm.
m is preferable, and in particular, 10 to 30 μm is preferable.

When the photosensitive layer has a laminated structure, the thickness of the charge generation layer is preferably from 0.01 to 10 μm, particularly preferably from 0.1 to 10 μm.
The thickness of the charge transport layer is preferably 5 to 40 μm.
μm is preferred, and particularly preferably 10 to 30 μm.

Further, in order to protect these photosensitive layers from external mechanical and chemical adverse effects, a thin protective layer such as a resin layer or a resin layer in which conductive particles are dispersed may be provided on the surface of the photosensitive layer.

The electrophotographic photoreceptor of the present invention can be widely applied not only to printers such as laser beam printers, LED printers and CRT printers, but also to general electrophotographic copying machines and other electrophotographic applications.

[0047]

EXAMPLE 50 parts of titanium oxide powder coated with tin oxide containing 1.10% antimony oxide, 25 parts of resole type phenol resin, 20 parts of methyl cellosolve, 5 parts of methanol and silicone oil (polydimethylsiloxane polyoxy resin) Alkylene copolymer, average molecular weight 300
0) 0.002 parts were dispersed in a sand mill using glass beads having a diameter of 1 mm for 2 hours to prepare a paint for a conductive layer.

Aluminum cylinder (outer diameter 30 mm ×
The above paint is applied by dip coating on
After drying at 30 ° C. for 30 minutes, a conductive layer having a thickness of 20 μm was formed.

A solution obtained by dissolving 5 parts of a 6-66-610-12 quaternary copolymerized polyamide resin in a mixed solvent of 70 parts of methanol and 25 parts of butanol was applied by a dipping method and dried. A pull layer was provided.

Next, 4 parts of the oxytitanium phthalocyanine crystal obtained in Synthesis Example 1 of the present invention, 1.0% by weight of the oxytitanium phthalocyanine, metal-free phthalocyanine and 2 parts of a polyvinyl butyral resin were added to 100 parts of cyclohexanone. And dispersed in a sand mill using glass beads having a diameter of 1 mm for 2 hours.
A solution diluted by adding 00 parts of methyl ethyl ketone was collected to obtain a coating liquid. This was applied on the undercoat layer and dried at 80 ° C. for 10 minutes to form a 0.15 μm-thick charge generation layer.

Next, the following structural formula

[0052]

[Outside]

Was prepared by dissolving 10 parts of the compound represented by the following formula and 10 parts of a bisphenol Z-type polycarbonate resin in 60 parts of monochlorobenzene, and applied to the charge generation layer by dipping. This was dried at a temperature of 110 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm. This photoreceptor was mounted on a laser beam printer [trade name: LBP-SX (manufactured by Canon)], charged to a dark area potential of -700 (V), and irradiated with a laser beam having a wavelength of 802 nm. The amount of light required to bring the potential of -700 (V) to -150 (V) was measured, and the value was used as the sensitivity.

Next, in the above-mentioned potential setting, the image evaluation of the photoreceptor was performed by paying attention to "fog" of the solid white portion.

Further, the stability of the dispersion for the charge generation layer was evaluated under the following three conditions. (1) Leaving the stopper tightly closed (2) Open stirring (solvent evaporation loss is appropriately supplemented) (3) Continuous operation with a circulation coating device consisting of a stirring tank, circulation pump, festival meter and filter (Fig. 5) The cohesiveness was determined by whether the paper was clogged (whether the pressure gauge rose) or the aluminum sheet was immersed in the dispersion and pulled up, and whether particulate matter was found on the dried film.

In FIG. 5, reference numeral 6 denotes an application tank, 7 denotes a reservoir, 8 denotes a pump, 9 denotes a pressure gauge, and 10 denotes a filter. 2. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the content of the metal-free phthalocyanine was 0.1% by weight. Table 1 shows the results. 3. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the content of the metal-free phthalocyanine was 10.0% by weight. Table 1 shows the results. 4. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the content of the metal-free phthalocyanine was 30.0% by weight. Table 1 shows the results. 5.6.7. And 8. Electrophotographic photoreceptors were prepared and evaluated in the same manner as in Examples 1, 2, 3 and 4, except that the oxytitanium phthalocyanine obtained in Synthesis Example 2 was used as the oxytitanium phthalocyanine. Table 1 shows the results. 9. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 5 except that the amount of the metal-free phthalocyanine was changed to 40% by weight.
Table 1 shows the results.

Comparative Example 1 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 5 except that no metal-free phthalocyanine was used.

(Comparative Example 2) As oxytitanium phthalocyanine,
Example 5 except that A-type oxytitanium phthalocyanine synthesized by the production method described in JP-A-7094 was used.
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 1 shows the results.

(Comparative Example 3) Oxytitanium phthalocyanine described in JP-A-61-2
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 5, except that α-type oxytitanium phthalocyanine synthesized by the production method described in JP-A-39248 was used. Table 1 shows the results.

[0059]

【table】

[0060]

As described above, according to the present invention, it is possible to obtain a dispersion for a photosensitive layer having extremely excellent dispersion stability, and as a result, it is possible to obtain a high-sensitivity, high-quality electrophotographic photosensitive liquid. Body can be provided.

[Brief description of the drawings]

FIG. 1 is a CuKα characteristic X-ray diffraction diagram of oxytitanium phthalocyanine obtained in Synthesis Example 1.

FIG. 2 is a CuKα characteristic X-ray diffraction diagram of the oxytitanium phthalocyanine obtained in Synthesis Example 2.

FIG. 3 is a structural example (single layer) of a photosensitive layer of the electrophotographic photosensitive member of the present invention.

FIG. 4 is a structural example (lamination) of a photosensitive layer of the electrophotographic photosensitive member of the present invention.

FIG. 5 is a schematic diagram of a circulation coating apparatus used in Examples and Comparative Examples.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 5/06

Claims (2)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer has a Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction of 9.0 °, 1 °.
Oxytitanium phthalocyanine or CuKα with strong peaks at 4.2 °, 23.9 ° and 27.1 °
Bragg angles (2θ ± 0.2 °) in characteristic X-ray diffraction are 7.4 °, 9.2 °, 10.4 °, 11.6 °, and 13.
0 °, 14.3 °, 15.0 °, 15.5 °, 23.4
An electrophotographic photosensitive member containing oxytitanium phthalocyanine having strong peaks at °, 24.1 °, 26.2 °, and 27.2 °, and containing metal-free phthalocyanine. 2. The electrophotographic photosensitive member according to claim 1, wherein the content of the metal-free phthalocyanine is 0.1 to 30% by weight of the oxytitanium phthalocyanine.