JPS62177069A - Novel phthalocyanine crystal and electrophotographic photosensitive material using said crystal - Google Patents

Abstract

NEW MATERIAL:A chlorinated aluminum phthalocyanine, expressed by the formula AlClxC32N8H(17-x-y)Cly (x+y is 1.0-3.0) and having (A) strong diffraction peaks at 6.7 deg., 11.2 deg., 16.7 deg. and 25.6 deg. Bragg angles (2theta+ or -2 deg.) in an X-ray diffraction spectrum and (B) the maximum absorption at 640-660nm in a transmission absorption spectrum. USE:An electron charge generating agent for electrophotographic photosensitive materials. PREPARATION:Condensation reaction of phthalodinitrile with aluminum chloride is initiated in the absence of a solvent while heating.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a specified phthalocyanine crystal and an electrophotographic photoreceptor using the same as a charge generating agent.

An object of the present invention is to provide a modified chlorinated aluminum phthalocyanine crystal that has excellent charge generation ability and is effective as a charge generation agent, and to combine this crystal with a charge transfer agent as a charge generation agent to provide electrophotography with excellent performance. To provide a photoreceptor for use.

(Prior Art) Since the invention of electrophotographic photoreceptors by Carlson, many photoreceptors have been developed and are used in many fields such as copying machines, photoengraving, and printers. Particularly recently, there has been a remarkable development in the field of printers, and there is a particular demand for electrophotographic photoreceptors that are compatible with light sources such as light emitting diodes, conductor lasers, and He/Ne gas lasers.

In order to meet these demands, inorganic and organic photoreceptors have been devised.

As inorganic photoreceptors, amorphous silicon, selenium-tellurium compounds, selenium-arsenic compounds, etc. are known.As for organic photoreceptors, charge generating agents such as phthalocyanines, fused polycyclic compounds, and azo compounds are known. It is known that pigments and other dyes are used in combination with various charge transfer agents.

Among these photoreceptors, in order to be particularly compatible with light-emitting diode light sources, photoreceptors that efficiently absorb light from light-emitting diodes and
A charge generating agent with a low charge generation rate is required.

;'i i light'h Phthalocyanine is one of the four substances.

Compared to other photoconductors, the absorption wavelength extends to longer wavelengths,
There are many examples of practical use because of its ability to generate charges.

What is particularly noteworthy about photoreceptors using phthalocyanines is that when phthalocyanines are used as charge generating agents, they are used in the form of specific crystals.

For example, when using the same metal-free phthalocyanine,
From the types, there are more τ and η types shown in JP-A-58-182639, as well as the Journal of Physical Chemistry [J.

phys, chem, 27, 3250 (196
Various crystal forms are known, such as the α and β types described in 8)], and the ε type described in Japanese Patent Publication No. 52-1667, as well as tfC and copper phthalocyanine.
Crystal forms such as α, β, γ, π, χ, and ρ are known.
It is known that differences in crystal type bring about differences in photoconductivity. Therefore, in order to use phthalocyanines as a charge generating agent for a photoreceptor, it is necessary to accurately specify the crystal structure and use a phthalocyanine containing an effective crystal structure.

Among the above-mentioned phthalocyanines, photoreceptors using chlorine-ratio aluminum phthalocyanine crystals as total charge generating agents, such as chloraluminum phthalocyanine and chloraluminum phthalocyanine chloride, have particularly high spectral sensitivity to long wavelengths.

Its spectral sensitivity ranges from the visible range around soo nm to 9
Since it extends to the near infrared region of 0.00 nm, it is known to be useful as a photoreceptor for electrophotography using various and diverse light sources. For example, Ivanov Chemical Research Laboratory Report (1972
, February 2), 1905-1908, it is stated that chloraluminum phthalocyanine exhibits photoconductivity, and furthermore, in Japanese Patent Publication No. 48-34189, polychloraluminum phthalocyanine is used as a photoreceptor for electrophotography. It is stated that it can be used as a. In addition, %KOKAI No. 57-211149 and JP-A-58-158649 disclose special X-ray diffraction spectra and infrared absorption spectra obtained by solvent treatment of vapor-deposited films of chloraluminum phthalocyanine or chloraluminum phthalocyanine chloride. It has been stated that the aluminum phthalocyanine having the above is useful as a charge generation layer of a laminated electrophotographic photoreceptor having high sensitivity in the near-infrared region. Furthermore, the present inventors have determined that AtCtCstNaH (+s, a ~ +
4.4) Chloraluminum phthalocyanine represented by C4 (o, a to t, e) Chloraluminum phthalocyanine chlorinated IJ)"tt As a result of studying the electrophotographic photoreceptor as a charge generating agent, it was found that the phthalocyanine is present as a vapor-deposited thin film. As for b, the dispersion coating of fine particles purified by sublimation has low charge generation ability, and by treating it in a solvent that has affinity for phthalocyanine, such as toluene, xylene, chloroform, etc., it can generate specific X-rays. It was discovered that chloraluminum phthalocyanine chloride having diffraction properties was obtained and showed extremely excellent charge generation ability from the visible region to the near-infrared region (Japanese Patent Laid-Open No. 58-209748).

(Problem to be Solved by the Invention 9 As mentioned above, chlorine f hyaluminum phthalocyanine is 741 Hm as made by vapor deposition or sublimation.
By applying a solvent treatment to a crystal type that has an absorption maximum at a wavelength (750 nm to 850 nm), the absorption maximum occurs at a wide range of wavelengths (750 nm to 850 nm)! Broadly speaking, only two crystal types have been found. Moreover, 740nmK without any solvent treatment
When forming a charge transport layer dissolved in an organic solvent by coating, the crystal form having the absorption maximum becomes substantially the same as when the charge transfer layer is treated with a solvent.
Luminium phthalocyanine crystal form 1d, 750n
It is the only crystal type that has an absorption maximum between m and 850 nm. In this way, the LA element (B
Electrophotographic photoreceptors using aluminum phthalocyanine in the charge generation layer have high photosensitivity in the near-infrared region;
Since the absorption coefficient is small near 660 nm, which is the oscillation wavelength of a light emitting diode, the sensitivity is lower than in the near-infrared region, and there is a drawback that it cannot be applied to a printer using a light emitting diode as a light source.

(Means for Solving the Problems) In order to improve the above-mentioned drawbacks, the present inventors have conducted intensive studies on the crystal transformation behavior of chlorinated aluminum phthalocyanine, and as a result, have developed a new modified crystalline material having maximum absorption in the range of 640 to 660 nm. We succeeded in developing this and completed the present invention.

That is, the present inventors found that AACtxCstNaH(t
y-x-y) C4y CX 1'j = 1.0~3.
0) T: By treating the indicated chlorinated aluminum phthalocyanine with pure water, (a) the Bragg angle (2θ ± 2 degrees) was 6.7 degrees in the X-ray diffraction spectrum,
It has strong diffraction peaks at 11.2 degrees, 16.7 degrees, and 23.6 degrees, and (b) 640 to 6 in the transmission absorption spectrum.
They discovered a new crystal type that has maximum absorption at 60 nm, and further discovered that an electrophotographic photoreceptor using this crystal type as a charge generating agent exhibits extremely high photosensitivity at 670 nm, leading to the completion of the present invention. Ta.

The chlorinated aluminum phthalocyanine used in the present invention can be easily sweetened by causing a condensation reaction between phthalodinitrile and aluminum chloride under heating without a solvent. The thus obtained chlorinated aluminum phthalocyanine is purified by repeated washing with an organic solvent and water, and further purified by sublimation to remove trace amounts of impurities. In order to use the specific chlorinated aluminum phthalocyanine as a charge generating agent in the present invention, it can be obtained by treating the chlorinated aluminum phthalocyanine obtained by sublimation purification or vapor deposition with water.

The X-ray diffraction spectrum of chlorine [hyaluminum phthalocyanine] treated with water is shown in Figure 1.
±2 degrees is 6.7 degrees, 11.2 summer, 16.7, 23
．． A strong diffraction peak was observed at 6Mj, indicating that the crystal type had changed from that purified by sublimation.

Furthermore, as shown in Figure 2, its transmission absorption spectrum shows a maximum absorption of 640 to 660 nmK, which is clearly different from that of the untreated one. It is clear that fc chlorine 1 hyaluminum phthalocyanine, which exhibits maximum absorption at 850 nm K and is treated with water, is a completely new crystal type that has not been found before. The crystalline form obtained by the treatment with a shredded garden tree remains unchanged and stable even after subsequent treatment with an organic solvent. In addition,
In Figures 9-1 and 2, (a) is the case where IA was purified by sublimation and no treatment (comparative example), (b) is the case where the IA was treated with water (invention), ( C) shows the case (comparative example) treated with an organic solvent.

Next, processing conditions for obtaining the chlorinated aluminum phthalocyanine of the present invention were investigated. When treating non-grade chlorinated aluminum phthalocyanine obtained by vapor deposition, the vapor deposited film is placed in pure water for 2 hours at 6DC or at a higher temperature of 8
It can be obtained by soaking for 1 hour at 0C, or when processing sublimation-purified chlorinated aluminum phthalocyanine powder, it can be obtained by immersing it in a ball mill with pure water for 20 hours or more, or by irradiating it with ultrasonic waves for 1 hour or more. .

In order to use the chlorinated aluminum phthalocyanine yi charge generation layer of the present invention, the charge generation layer is provided on a conductive substrate. Metal can be used. Further, for the purpose of improving memory resistance, a zinc oxide layer or a methanol-soluble polyamide layer using polyvinyl alcohol as a binder may be provided on the conductive substrate to a thickness of 1 μm or less.

In the case of vapor deposition, the chlorinated aluminum phthalocyanine as the charge generation layer can be obtained by immersing the non-grade chlorinated aluminum phthalocyanine obtained by vapor deposition on the conductive substrate in pure water. In addition, when used in the form of fine particles, the sublimated AI chlorinated aluminum phthalocyanine powder is treated in pure water by ball milling or ultrasonic irradiation, and then used as is or in acrylic resin.

A charge generation layer can be formed by applying a solution of a binder such as styrene resin, alkyd resin, polyester resin, polyamide resin, polycarbonate resin, etc. together with a solvent onto a conductive substrate. The amount of the binder used in this case is not particularly limited, but it is used in an amount of 20 to 200 parts by weight per 100 parts by weight of chlorinated aluminum phthalocyanine. The thickness of the charge generation layer at this time is desirably 200 to 100X when formed by vapor deposition, and the dry thickness is preferably 0.02 to 5 .mu.m when formed by solution coating.

Next, a charge transfer layer is laminated on the chlorinated aluminum phthalocyanine charge generation layer created as described above to form a photoreceptor. It is necessary that the layer is transparent to light in the photosensitive wavelength range of the charge generation layer, and in order to obtain an optimal photoreceptor, the energy transfer layer between the charge transfer layer and the charge generation layer must be transparent. It is necessary to appropriately adapt the level (ionization potential, atom affinity, etc.), and the charge transfer agent may be used alone or in the form of being dissolved or dispersed in a binder resin.

As the sole transfer agent, 2,6-simethoxy9.10
Polyesters obtained from -dihydroxyanthracene and dicarboxylic acids, polyethers obtained from 2,6-simethoxy9.10-dihydroxyanthracene and dihalogen compounds, and polyvinylcarbazole can be used.

As the transfer agent used dispersed in the binder resin, 2,6
, 9. Anthraceph fj a'J form such as 10-tetraisopropoxyanthracene, oxacyazoles such as 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, 1-phenyl -5-(p-diethylaminostyryl)-5-(1)-
pyrazoline derivatives such as diethylaminophenyl]-pyrazoline.

Nutrilyl compounds such as 4-(diethylamino)styryl-2-anthracene and hydrazone compounds such as p-diethylaminobenzaldehyde (diphenylhydrazone) can be used.

In addition, as the binder resin of the transfer agent, polysalt f-vinyl, polyether, polystyrene, polyester,
Examples include styrene-butadiene copolymer, polyurethane, and epoxy resin. The amount of binder resin is 10
It is used in an amount of 60 to 200 parts by weight relative to 0 parts by weight. At this time, the thickness of the charge transfer layer is not particularly limited, but 6 to 20 μm is appropriate from the relationship with the acceptance potential.

(Examples) Hereinafter, the present invention will be explained in more detail using Examples, and Comparative Examples will be listed.

Example 1 Copolymerized nylon (
Toshi CM4001) was dissolved in methanol to 1% by weight.
The solution was applied by dip coating, and the dry film thickness was 0.8 μm.
I made it so that On this board, kLcLc8. N,
Chlorinated aluminum phthalocyanine, denoted by H, s, a cm, 4, was deposited at f 10-' torr to a thickness of 5
A deposited film having a size of 0.00 was obtained. The deposited film was immersed in pure water at 60C for 2 hours to create a charge generation layer. For comparison, the deposited film was immersed in toluene for 30 minutes at room temperature to form a charge generation layer (
Comparative example).

On top of this, a solution consisting of 10 parts of p-diethylaminobenzaldehyde (diphenylhydrazone), 10 parts of polycarbonate resin "Panlite L-1250J (manufactured by Yondai Kasei Co., Ltd.), and 40 parts of 1,2-dichloroethane" was applied. , vacuum dry.

A charge transfer layer having a dry film thickness of 12 μm was formed, and the entire photoreceptor was manufactured.

To evaluate the characteristics of the photoreceptor, the photoreceptor was corona charged at -5.5 KV using a SP 428 tester manufactured by Kawaguchi Electric, and the optical attenuation of the surface potential was obtained using an interference filter (manufactured by Japan Vacuum Optics).23. Measure by irradiating monochromatic light of 84 nW/ct/l, calculate the annihilation exposure energy (μJ/7) from the time it takes for the surface potential to decrease to 1/2, and take the reciprocal as the half-reduction exposure sensitivity (cIIt/μJ). evaluated. As a result, at 670 nm, the example had a surface potential of 580 V,
The half-reduction exposure sensitivity was 3.5 (Cd/μJ), but in the comparative example, one surface potential was 6oov, and the reduction exposure sensitivity was 2.5 (cr
t/μJ).

FIG. 3 shows the spectral sensitivities of Example (a) and Comparative Example (b). As is clear from FIG. 3, the photoreceptor of the present invention is
Shows high sensitivity in the wavelength region shorter than 750 nm.

Example 2 In Example 1, ktctc8. N,H,,,6C4,
, for chlorinated aluminum phthalocyanine.

The same procedure as in Example 1 was carried out except that chlorinated aluminum phthalocyanine represented by ktctc, , N, H, 6 was used. The photoreceptor performance at 670 nm was as follows.

Surface potential 590v Half-decrease exposure sensitivity 3.4 (al/μJ) Example 3 Copolymerized nylon (CM40 manufactured by Toshi) with a dry film thickness of 0.8 μm
01) was coated with chlorinated aluminum phthalocyanine f10-1lto, denoted by AtCAC3,N,H,...,C4,8.
rr to obtain a deposited film with a thickness of 500X. The deposited film was immersed in pure water at 80C for 1 hour to form a charge generation layer.

A charge transfer layer was formed thereon in the same manner as in Example 1.

A photoreceptor was created. The photoreceptor performance at 670 nm is a surface potential of 585V and a half-life lightning sensitivity of 3.4 (ffl/
μJ).

Example 4 AlCIC5t NaHts obtained by sublimation purification.

6C/! 8 parts by weight of chlorinated aluminum phthalocyanine shown in 4.4 and 560 parts by weight of pure water were sealed in a glass ball mill and ground for 40 hours. The resulting dispersion was heated to a thickness of 1
The charge generating layer was coated on a 0.00 μm aluminum sheet by dip coating to a dry film thickness of 0.1 μm.

On top of this, 100 parts by weight of polyester obtained from 2,6-simethoxy-9,10-dihydroxyanthracene and dodecanedioic acid was added to 700 parts by weight of trichloropropane, heated to 90C to make a uniform solution, and a dry film thickness of 15 μm was added.
The photoreceptor was prepared by applying heat to obtain a charge transfer layer and drying at 100 C for 1 hour to obtain a charge transfer layer. The photoconductor performance at 670 nm is 1 surface potential 570V, half exposure sensitivity 3
．． 1 (cm/μJ).

Example 5 AtC1C5t NaH obtained by sublimation 'lfI production
8 parts by weight of chlorinated aluminum phthalocyanine having a rating of +3.6 C/4.4 and 1 part by weight of pure water are sealed in a glass ball mill and pulverized for 40 hours. A solution obtained by dissolving 8 parts by weight of an acrylic resin (Acridic A-801, manufactured by Dainippon Ink) in 560 parts by weight of chloroform is added to the obtained dispersion, and the mixture is further pulverized for 1 hour. This coating liquid = 1
7- Copolymerized nylon with a dry film thickness of 0.8 μm (CM4o manufactured by Toshi)
o1)'! A charge generation layer was prepared by dip coating onto a 100 μm thick aluminum sheet coated with R so that the dry film thickness was 0.1 μm. On top of this, a charge transfer layer was formed in the same manner as in Example 4, and a photoreceptor was prepared.

Photoreceptor performance at 670 nm is 1 surface potential of 620 ■
, the half-reduced exposure sensitivity was 3.0 (m/μJ).

(Effect of the invention) The chlorinated aluminum phthalocyanine of the present invention is.

Electrophotographic photoreceptors containing modified chlorinated aluminum phthalocyanine crystals, which are effective as charge generating agents, as the main component of the charge generating layer, have high sensitivity in the short wavelength region, as is clear from the examples. It shows extremely excellent performance.

[Brief explanation of drawings]

Figure 1 shows AtC6xcstNaH(t, -x-y)Ct
)' (X + y = 1.0 to 3.0). FIG. 3 is a graph showing the spectral sensitivity of the photoreceptor.

Claims (2)

[Claims] (1) (a) In the X-ray diffraction spectrum, the Plagg angle (
2θ±2 degrees) are 6.7 degrees, 11.2 degrees, 16.7 degrees, 2
AlCl_XC_3_2N_8H_(
_1_7_-_x_-_y_)Cl_y(x+y=1.
0 to 3.0). (2) In a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive substrate, (a) the Bragg angle (2θ±2 degrees) in the X-ray diffraction spectrum is 6.
It has strong diffraction peaks at 7 degrees, 11.2 degrees, 16.7 degrees, and 25.6 degrees, and (b) 64 degrees in the transmission absorption spectrum.
AlCl_XC_3 with maximum absorption between 0 and 660 nm
_2N_8H_(_1_7_-_x_-_y)Cl_y
A photoreceptor for electrophotography, characterized in that a charge generation layer contains a chlorinated aluminum phthalocyanine represented by (x+y=1.0 to 3.0) as a main component.