JPH03182766A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity and to eliminate the image defects by a transfer memory by incorporating oxotitanium phthalocyanine together with aluminum phthalocyanine at a specific ratio thereof into a photosensitive layer. CONSTITUTION:The oxotitanium phthalocyanine having the high sensitivity to light of long wavelengths and the aluminum phthalocyanine of 0.1 to 5,000ppm of this oxotitanium phthalocyanine are incorporated into the photosensitive layer 1 formed on a conductive base 3. The sensitivity of the elecrophotographic sensitive body formed by using the oxotitanium phthalocyanine as a charge generating material 2 is improved in this way and the image defects occurring in a transfer memory are substantially eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing oxotitanium phthalocyanine and aluminum phthalocyanine as charge-generating materials in the photosensitive layer.

[Prior Art] In recent years, non-impact printers that apply electrophotographic technology have become widely used as terminal printers in place of conventional impact printers. 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 material, and many charge-generating materials are being studied.

Typical charge generating materials include phthalocyanine pigments, azo pigments, cyanine dyes, azulene dyes, squarylium dyes, and the like.

On the other hand, as charge-generating materials sensitive to long-wavelength light, aluminum phthalocyanine, chloroindium phthalocyanine, vanadyl phthalocyanine, chlorogallium phthalocyanine, magnesium phthalocyanine,
Many studies have been conducted on metal phthalocyanines such as oxotitanium phthalocyanine (titanyl phthalocyanine) or metal-free phthalocyanines (metal-free phthalocyanine).

Among these, many phthalocyanine compounds are known to have polymorphisms; for example, metal-free phthalocyanine has α-type, β-type, γ-type, δ-type, ε-type, χ-type, τ-type, etc., and copper phthalocyanine has polymorphism. Generally known types include α type, β type, γ type, δ type, ε type, and χ type.

It is also generally known that the crystal type has a great influence on electrophotographic properties (sensitivity, potential stability during long-term use, etc.) and coating properties when made into a coating.

Furthermore, oxotitanium phthalocyanine, which has particularly high sensitivity to long-wavelength light, has polymorphisms as well, as with many phthalocyanines such as the above-mentioned metal-free phthalocyanine and copper phthalocyanine.

For example, Japanese Patent Application Laid-open No. 59-49544 (correspondence: U, S
,P.

4, 444.861), JP-A-59-166959, JP-A-61-239248 (correspondence: Ll,
S, P, 4,728.592), JP-A-62-6
Publication No. 7094, (correspondence: U, S, P, 4.6
64.997), JP-A-63-366, JP-A-6
Oxotitanium phthalocyanine having different crystal forms has been reported in JP-A No. 3-1!6158, JP-A-63-198067, and JP-A-64-17066.

[Problems to be Solved by the Invention] The present invention aims to improve the sensitivity of an electrophotographic photoreceptor using oxotitanium phthalocyanine as a charge generating material, and to improve the charging memory (hereinafter referred to as transfer memory) that occurs during the transfer process when used in a reversal development system. The main purpose is to improve image defects caused by

[Means for Solving the Problems] The present inventors have discovered a method of improving the sensitivity of an electrophotographic photoreceptor using oxotitanium phthalocyanine as a charge generating material and eliminating almost all image defects caused by transfer memory, and have developed the present invention. completed.

That is, the object of the present invention is to contain oxotitanium phthalocyanine in the photosensitive layer and usually 0.1 to 5000 ppm, preferably 0.5 to 3.0 ppm relative to the oxotitanium phthalocyanine.
This is achieved by an electrophotographic photoreceptor characterized in that it contains aluminum phthalocyanine in an amount of 1,000 ppm, optimally 1 to 11,000 ppm.

The structure of oxotitanium phthalocyanine is represented by

Here, x', x'', x'' and X4 are CI2 or Br
, where n, m, Q and k are integers of O to 4.

The method for producing oxotitanium phthalocyanine according to the present invention will be exemplified.

First, for example, titanium tetrachloride and orthophthalodinitrile are reacted in α-chlornaphthalene to obtain dichlorotitanium phthalocyanine. This is washed with a solvent such as α-chloronaphthalene, trichlorobenzene, dichlorobenzene, N-methylpyrrolidone, N,N-dimethylformamide, etc., then washed with a solvent such as methanol or ethanol, and then hydrolyzed with hot water. Oxotitanium phthalocyanine crystals are obtained. Since the crystals thus obtained are often a mixture of various polymorphs, they are converted into amorphous oxotitanium phthalocyanine by processing using an acid pasting method.

Next, this amorphous oxotitanium phthalocyanine was added to 4
Milling at 0 to 200°C, preferably 60 to 120°C, and then adding a solvent such as cyclohexanone for 5 minutes to
Oxotitanium phthalocyanine crystals of the present invention can be obtained by treatment for 24 hours, preferably 15 minutes to IO hours.

The X-ray diffraction pattern of the oxotitanium phthalocyanine crystal in the present invention has strong peaks at Bragg angles of 2θ±0.2° of 7.4@, 9.2°, 10.4° and 11.6°.
13.0°, 14.3°, 15.0@
, 15.5°23.4°, 24.1°, 26.
They are observed at positions of 2° and 27°2°, and the above peaks were selected from the top 16 points with the highest peak intensities. The specific diffraction pattern is shown in FIG. 1, for example.

Hereinafter, the typical layer structure of the electrophotographic photoreceptor of the present invention will be explained as follows.
As shown in FIG.

In FIG. 2, the photosensitive layer 1 consists of a single layer, and the photosensitive layer 1 simultaneously contains a charge-generating material 2 and a charge-transporting material (not shown).

Note that 3 is a conductive support.

In FIG. 3, the photosensitive layer 1 has a laminated structure of a charge generation layer 4 and a charge transport layer 5, and the charge generation layer 4 contains the charge generation material 2. In FIG.

Note that the stacking relationship between the charge generation layer 4 and the charge transport layer 5 shown in FIG. 3 may be reversed.

When manufacturing the electrophotographic photoreceptor of the present invention, the conductive support 3 may be any material as long as it has conductivity, and may be a metal such as aluminum or corrosion-resistant steel (stainless steel), or an original conductive material provided with a conductive layer. Examples include plastic and paper, and 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, polyamide, glue, gelatin, etc. are used.

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

When forming a photosensitive layer consisting of a single layer as shown in FIG. 2, for example, the oxotitanium phthalocyanine charge generating material and the charge transporting material of the present invention are mixed in a suitable binder resin liquid, such as a solution, as described below. It can be obtained by coating and drying.

The charge generation layer of the photosensitive layer having a laminated structure as shown in FIG. 3 can be formed by dispersing the oxotitanium phthalocyanine charge generation material of the present invention together with a suitable binder resin solution, coating and drying. I can do it. In this case, the binder resin may be omitted.

Examples of the binder resin used here include polyester resin, acrylic resin, polyvinylcarbazole resin, phenoxy resin, polycarbonate resin, polyvinyl butyral resin, polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, or vinylidene chloride/acrylonitrile copolymer. Coalescent resin etc. are mainly used.

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

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

Moreover, as the binder resin, those mentioned above 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 is a single layer, the film thickness is 5 to 40 μm, preferably 10 to 30 μm.

Further, when the photosensitive layer has a laminated structure, the thickness of the charge generation layer is 0.
The charge transport layer has a thickness of 5 to 40 μm, preferably 10 to 30 LLm.

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

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

Hereinafter, parts refer to parts by weight.

[Synthesis Example 1] In 100 parts of α-chlornaphthalene, 5.0 parts of 0-phthalodinitrile and 13.5 parts of titanium tetrachloride were mixed at 200°C with 3 parts of
After heating and stirring for an hour, the mixture was cooled to 50° C. and the precipitated crystals were filtered off to obtain a paste of dichlorotitanium phthalocyanine. Next, this was heated to 100°C and N,N'-
The mixture was washed with 100 parts of dimethylformamide under stirring, then washed twice with 100 parts of methanol at 60°C, and then filtered.

Further, the resulting paste was dissolved in 100 parts of deionized water.
After stirring at 80° C. for 1 hour, the mixture was filtered to obtain blue oxotitanium phthalocyanine crystals.

The elemental analysis values of this compound were as follows.

Elemental analysis value (C3J+aNaTiO) CHN 1 Calculated value (%) 66.6g 2.80 19.44
0.00 Actual value (%) 6G, 50 2.99 1
9.42 0.47 Next, the crystals were dissolved in 30 parts of concentrated sulfuric acid, added dropwise to 300 parts of deionized water at 20°C under stirring to re-precipitate, and then filtered to obtain amorphous oxotitanium. Phthalocyanine was obtained. 10 parts of the amorphous oxotitanium phthalocyanine thus obtained were mixed with 15 parts of sodium chloride and 7 parts of diethylene glycol, and
Milling treatment was performed for 60 hours in an automatic mortar under heating at 0°C. Next, sufficient water washing was performed to completely remove the sodium chloride and diethylene glycol contained in this treated product. After drying this under reduced pressure, 200 parts of cyclohexanone and glass beads with a diameter of 1 mm were added, and 30 parts of
Processing was carried out using a sand mill for a minute to obtain oxotitanium phthalocyanine crystals of the present invention. The X41 diffraction pattern of this oxotitanium 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 a Cu- line.

Measuring device used: Rigaku Denki X-ray diffraction device X-ray bulb: Cu Voltage: 50kV Current: 40mA Scan method: 2θ/θ scan Sampling interval: 0.020deg.

Start angle (2θ): 3deg.

Stop angle (2θ): 40deg.

Divergence slit: 0.5deg.

Scattering slit: 0.5deg.

Receiving slit: 0.3+++n+ curved monochromator used The electrophotographic photoreceptor of the present invention is widely applicable not only to printers such as laser beam printers, LED printers, and CRT printers, but also to ordinary electrophotographic copying machines and other electrophotographic application fields. can do.

Furthermore, the oxotitanium phthalocyanine used in the present invention is not limited to those having the above-mentioned crystal structure;
Correspondence: Oxotitanium phthalocyanine crystal called α type disclosed in [1, S, P, 4.728.592), JP-A-62-67094 (Correspondence: U, S, P, 4) Oxotitanium phthalocyanine crystal known as type A disclosed in .664.997).

Further, it is also possible to use oxotitanium phthalocyanine crystals having a crystal type disclosed in Japanese Patent Application Laid-open No. 17066/1984.

Example 1 50 parts of titanium oxide powder coated with tin oxide containing 10% antimony oxide, 25 parts of resol type phenolic resin
parts, 20 parts of methyl cellosolve, 5 parts of methanol, and silicone oil (polydimethylsiloxane polyoxyalkylene copolymer, average molecular weight 3000) 0.002
The mixture was mixed and dispersed for 2 hours using a sand mill containing glass beads having a diameter of 1 mm to prepare a coating material for a conductive layer.

Aluminum cylinder (outer diameter 30mm x length 260mm,
The above paint was applied by dip coating onto a 5mm thick film and dried at 140°C for 30 minutes to obtain a film thickness of 201mm. A conductive layer of Lm was formed.

On top of this, a solution of 5 parts of 6-66-610-12 quaternary polyamide copolymer resin dissolved in a mixed solvent of 70 parts of methanol and 25 parts of butanol was applied by a ditzing method and dried to form a subbing film with a thickness of 1 μm. Layers were provided.

Next, 4 parts of the oxotitanium phthalocyanine crystal obtained in Synthesis Example 1 of the present invention and the oxotitanium phthalocyanine crystal were added to 4 parts of the oxotitanium phthalocyanine crystal. lppm of aluminum phthalocyanine and 2 parts of polyvinyl butyral resin were added to 100 parts of cyclohexanone, mixed and dispersed for 2 hours in a sand mill containing glass beads with a diameter of 1 mm, and 100 parts of methyl ethyl ketone was added to this, and after dilution, the mixture was collected and coated. After obtaining the working solution and coating it on the undercoat layer, it was heated at 80°C for 1
It was dried for 0 minutes to form a charge generation layer with a thickness of 0.15 μm.

Next, a solution was prepared by dissolving 10 parts of a charge transport material represented by the following structural formula and 10 parts of bisphenol 2 type polycarbonate resin in 60 parts of monochlorobenzene, and the solution was applied onto the charge generation layer by a dipping method. This was dried at a temperature of 110° C. for 1 hour to form a charge transport layer with a thickness of 20 μm.

Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 0.5 ppm.

Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 1 ppm.

Example 4 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was loppm.

Example 5 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 100 ppm.

Example 6 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 11,000 pp.

Example 7 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 3000 ppm.

Example 8 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 5000 ppm.

Comparative Example 1 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that aluminum phthalocyanine was not contained.

Comparative Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 0.011)I)IQ.

Comparative Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of aluminum phthalocyanine was 11,000 pp.

Sensitivity and image evaluation> Each of the photoreceptors obtained in Examples 1 to 8 and Comparative Examples 1, 2 and 3 was subjected to a laser beam printer [trade name:
LBP-SX (manufactured by Canon)], set the charge so that the dark potential is -700 (V), and attach it to the wavelength 8
-700 (V) when irradiated with 0.02 nm laser light
) The amount of light required to change the potential of -150 (V) was measured and defined as the sensitivity.

Next, in the above potential settings, the 1
After conducting a paper feeding durability test of 4,000 continuous sheets of B5 size paper using one type of photoreceptor, we tested A4-
Image evaluation was performed by focusing on the density of the image due to the transfer memory in the 85 portion.

These results are shown in Table 1.

As can be seen from Table 1, the ratio of aluminum phthalocyanine to oxotitanium phthalocyanine is 0.1 to 5000.
By adding ppm, it became possible to improve sensitivity and substantially eliminate image defects caused by transfer memory.

Table ○: Within the permissible range △: Outside the permissible range [Effects of the invention J] By containing aluminum phthalocyanine in an amount of 0.1 to 5000 ppm relative to oxotitanium phthalocyanine in the photosensitive layer of the present invention, sensitivity improvement and transfer memory can be achieved. It has become possible to substantially eliminate image defects caused by

[Brief explanation of drawings]

[Type of drawing] FIG. 1 is an X-ray diffraction diagram of the oxotitanium phthalocyanine crystal of the present invention, and FIGS. 2 and 3 are schematic cross-sectional views of the layer structure of an electrophotographic photoreceptor. [Main symbols in the figure] 1... Photosensitive layer, 2... Charge generation material, 3... Conductive support, 4... Charge generation layer, 5... Charge transport layer.

Claims (1)

[Claims] (1) Oxotitanium phthalocyanine in the photosensitive layer and 0.1 to 50% relative to the oxotitanium phthalocyanine.
An electrophotographic photoreceptor characterized by containing 00 ppm of aluminum phthalocyanine.