JPS61239248A - Composite electrophotographic photoreceptor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a composite electrophotographic photoreceptor used in a laser beam printer using a body laser.

[Conventional technology]

In 1968, it was discovered that 7 talocyanine compounds exhibited photoconductivity.
Since its discovery in 1997, a great deal of research has been conducted on it as a photoelectric conversion material. 2. Description of the Related Art In recent years, with the development of non-impact printing technology, research and development efforts have been actively conducted to develop laser beam printers that use semiconductor lasers as writing heads. In a laser beam printer used in electrophotography, first, a uniformly corona-charged photoreceptor is irradiated with a laser beam modulated based on an input signal, and an image is formed by toner development. It is believed that such a laser recording method improves the image quality and has the advantage that the use of a semiconductor laser in particular makes it possible to simplify, downsize, and reduce the cost of the device.

Currently, most of the oscillation wavelengths of semiconductor lasers that operate stably are in the near-infrared region (λ>780 nm). That is, the recording photoreceptor used therein needs to have high sensitivity in the wavelength range of 780 nm to 850 nm. In this case, the half-tfL exposure amount ET of monochromatic infrared light irradiation required as practical sensitivity is 10 erg/ise or less. Among photoconductive substances that exhibit high sensitivity in this long wavelength range, 7-thalocyanine compounds have attracted particular attention.

Conventionally, electrophotographic photoreceptors have been made of inorganic compounds such as selenium, tellurium, brittle cadmium, zinc oxide, or polyamide.
Organic compounds such as 1sl-vinylcarbazole and bisazo pigments are used. But these are 780 n
Although it has sufficient photosensitivity in the long wavelength range of m to 900 nm, in recent years, photoreceptors using alloys of selenium, tellurium, and arsenic or photoreceptors using dye-sensitized cadmium sulfide have been developed to It has been reported that they have high sensitivity in the long wavelength region, but all of them are highly toxic and their environmental safety is being reconsidered as a social issue. It is thought that photoreceptors using amorphous silicon may have the potential to extend the photosensitive region to long wavelength regions depending on specific doping and manufacturing methods.
At present, it is difficult to say that M is a low-cost photoreceptor because the film speed is slow and there are problems with mass production. Among the phthalocyanine compounds that have been investigated, compounds that exhibit high sensitivity in the long wavelength range of 780 nmJ and above include χ-type metal-free 7-thalocyanine, ε-type copper phthalocyanine, and vanadyl phthalocyanine. .

On the other hand, in order to increase the sensitivity, a laminated photoreceptor using a vapor-deposited film of 7-talocyanine as a charge generation layer was studied, and
Among the phthalocyanines whose central metal is gold 1j4' of Group A and Group II.

Some have been obtained with relatively high sensitivity. Documents related to this talocyanine include 1, for example, Japanese Patent Application No. 56-96040. 56-33977, 5
7-146538, 57-153.9'g2! , same 5
7-141581, 57-142458, 57-1
46538, 58-40798, etc. However, the formation of the vapor deposited film requires a high vacuum evacuation device, which increases the equipment cost, so the organic photoreceptor described above inevitably becomes expensive.

On the other hand, instead of using phthalocyanine as a group N film, it is used as a resin dispersion layer, and this is used as a charge generation layer.
Composite type photoreceptors made by coating charge transfer M thereon have also been considered, and as such composite type photoreceptors, L-thermal metal phthalocyanine (Japanese Patent Application No. 57-66963) and indium phthalocyanine (Japanese Patent Application No. 58-220493) have been studied. These are relatively highly sensitive photoreceptors, but the former has drawbacks such as a sharp drop in sensitivity in the long wavelength region of 800 nm or more, and the latter has the disadvantage of charge generation. When the layer is made of a resin dispersion system, there are many drawbacks such as insufficient sensitivity for practical use.

[Problem that the invention seeks to solve]

An object of the present invention is to provide an electrophotographic photoreceptor that exhibits high photosensitivity within the wavelength range of 500 to 900 nm.

[Means for solving problems]

The present invention has achieved the above object by providing a composite electrophotographic photoreceptor having a photosensitive layer comprising α-type titanyl phthalocyanine dispersed in a binder.

The titanyl phthalocyanine used in the present invention is (formula, Xl, X, , represents a number).

A particularly preferred titanyl phthalocyanine pack used in the present invention is titanyl phthalocyanine (TtOPc).
), titanylchloro7-thalocyanine (TI OPc C
1) and mixtures thereof.

The α-form titanyl phthalocyanine used in the present invention, for example, dichlorotitanium 7-thalocyanine (TiC12Pa) obtained by reacting titanium tetrachloride and 7-talodinitrile in an α-chloronaphthalene solvent, is hydrolyzed with t' aqueous ammonia or the like. 2-
Ethoxyethanol, diglyme, dioxane, tetrahydrofuran, h.

More preferably, the treatment is performed with an electron-donating solvent such as N-dimethylformamide, N-methylpyrrolidone, pyridine, or morpholine.

An X-ray diffraction pattern using Cu-K α rays of the α-type titanyl phthalocyanine used in the present invention thus obtained is shown in FIG. 1(b). This titanium phthalocyanine is 7.5° and 12.30s in the %XX-ray diffraction diagram.
Bragg angles 2θ of 1i3', 25.3°, and 28.7° (with an error range of ±0.2).

) has a relatively strong peak.

Figure 1 shows the X-ray diffraction diagram of β-type titanyl phthalocyanine recrystallized from α-chloronaphthalene [Figure 1 (el)]
Acid paste method [Processing method for obtaining α-type phthalocyanine described in "Phthalocyanine Compound J" by Moser and Thomas (published in 19753)]
The X-ray diffraction pattern of α-type titanyl phthalocyanine treated with [FIG. 1(a)] is also shown. These X-ray diffraction diagrams show that the titanyl phthalocyanine obtained by the above method is in the α form, and that the α form titanyl phthalocyanine has a Bragg angle of 2θ=7.5C%12.3216. s@
It can be seen that relatively strong peaks are shown at 25.3° and 28.7°.

The titanyl phthalocyanine used in the present invention has an X-ray diffraction pattern (α rays on Cu-) as shown in FIG. 1 (bl or (cl)).
It is of α form with .

Other α-type titanyl phthalocyanines used in the present invention are:
Despite differences in the halogen atoms, their substitution positions, or the number of substitutions, the five relatively strong peaks in common are observed in their X-ray diffractograms.

Examples of the resin used as a binder in the present invention include resins that are generally used as binders for electrophotographic photoreceptors.

Suitable examples include phenolic resin, area resin, melamine resin, epoxy resin, silicone resin, and vinyl chloride.
Examples include vinyl acetate copolymers, xylene resins, urethane resins, acrylic resins, polycarbonate resins, polyacrylate resins, saturated polyester resins, and phenoxy resins.

The electrophotographic photoreceptor of the present invention is preferably used by optically grinding α-type titanyl phthalocyanine into fine grains using a crusher such as a ball mill, sand mill, or attriter. Examples of the grinding agent in this case include commonly used glass beads, steel beads, and alumina beads, and if necessary, grinding aids such as common salt and bicarbonate of soda may also be used. In addition, if a dispersion medium is required during grinding, @ is preferably liquid at the temperature during grinding, such as 2-ethoxyethanol, diclime,
Examples include solvents that do not promote changes in crystal form, such as dioxane, tetrahydrofuran, N,N-dimethylformamide, N-methylpyrrolidone, pyridine, morpholine, or polyethylene glycol.

Charge-transporting substances are classified into hole-transporting substances and Hiroshima-transporting substances. Examples of hole-transporting substances include indoline compounds, quinoline compounds, and triphenylamine compounds, and as electron-transporting substances. is, for example, a bisazo compound, and when used, at least 1 m
It is more preferable to use a hole transport substance and at least one electron transport substance in combination. Examples of charge generating substances include perylene compounds and bisazo compounds.

Examples of indoline compounds include the general formula R1 (wherein R1 represents an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and R3 and Rs each independently represent a hydrogen atom, a halogen atom, or represents an alkyl group, aralkyl group, or aryl group that may have a substituent; R4 represents a hydrogen atom, a halogen atom, or an alkyl group or an aralkyl group that may have a substituent; %R and EL6 are each independently represents an alkyl group, aralkyl group or aryl group which may have a substituent, and R
3 and 86 may be integrated with each other to form a complete ring. ) can be mentioned. Preferable examples of indoline compounds used in the invention are summarized in Table 1.

Examples of quinoline compounds include general formulas R and R.

(In the formula, B represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, and Rlb Rlh and R3 each independently have a hydrogen atom, a halogen atom, or a substituent. (representing an alkyl group, an aralkyl group or an aryl group) can be mentioned. The quinoline compounds used in the present invention are summarized in Table 2.

The triphenylamine compound is a triphenylamine compound represented by the general formula Arc (where Ar, Arc, and Arc represent a substituted or unsubstituted aromatic carbocyclic group and a substituted or unsubstituted aromatic heterocyclic group). Phenylamine compounds can be mentioned, and preferred examples are listed in Table 3.

Table 3 Other well-known charge transport materials can also be used.
For example, derivatives of heterocyclic compounds such as pyrazole, pyrazoline, oxadiazole, thiazole, and imidazole, hydrazone conductors, triphenylmethane derivatives, poly-N
-Vinyl carbazole and its derivatives, etc.

The bisazo compounds used in the present invention may be those generally used in electrophotographic photoreceptors, and Table 4 lists bisazo compounds that are preferably used.

Examples of perylene compounds used in the present invention include:
Perylene compounds represented by the general formula (wherein R1 and R2 each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group, aryl group, alkylaryl group, or amino group) can be mentioned.

Specific examples of perylene compounds used in the present invention are summarized in Table 5.

The electrophotographic photoreceptor of the present invention can be prepared, for example, by adding the above-mentioned finely divided α-type titanyl phthalocyanine to a resin solution in a suitable organic solvent using a conventional dispersion machine (ball milling, paint shaker, Red Devil, etc.). (ultrasonic dispersion machine, etc.), and then spread it onto a conductive substrate.
It can be made by coating and drying. Application is usually done using a roll coater.

Use a wire bar, doctor blade, etc.

Suitable solvents include, for example, aromatic hydrocarbons such as benzene and toluene; ketones such as acetone and butanone; halogenated hydrocarbons such as methylene chloride and chloroform; ethers such as ethyl ether; Examples include cyclic ethers such as dioxane; esters such as ethyl acetate and methyl cellosolve acetate; one or more of these may be used.

The electrophotographic photoreceptor of the present invention can have a variety of structures. An example is shown in FIG. In Figure 3, the photoreceptor (al) is a conductive support (11) with a titanyl phthalocyanine compound (2), a hole transport material (4), and an electron transport material (5).
, and a binder (3). Further, the photosensitive layer may contain a charge generating substance (6) t-, if necessary.

The photoreceptor shown in FIG. 3 (bj) and FIG. 3 (c) has a charge carrier generation layer (Bl) consisting of a titanyl phthalocyanine compound (2) and a binder (3), and a hole transport substance (4). , the electron transport material (5) and the binder (3).
% is more preferably 5 to 20μ. In addition, Fig. 3 (b
In the case of a photoreceptor of (Cl, (d) and . Preferably, it is 3 to 50μ, more preferably 5 to 20μ.

The proportion of metal is 5 to 90x amount% of CLO to the photosensitive layer,
Preferably, it is 15-50%, and the proportion of the charge transport substance is 10-90%. :i%, preferably 10-60%
The proportion of the charge generating material is 10 to 70% by weight, preferably 60 to 50% by weight. In addition, in the production of any of the photoreceptors (al to (el) in FIG. 6,
Plasticizers can be used with binders.

As the conductive support for the photoreceptor of the present invention, for example, a metal plate or foil made of aluminum or the like, a plastic film deposited with a metal such as aluminum, or paper treated with electrical conductivity is used.

The photoreceptor obtained as described above is bonded between the conductive support and the original layer as required. j or a barrier layer can be provided. Materials for these layers include polyamide, nitrocellulose, casein, and polyvinyl alcohol. It is desirable that the film thickness be 1 μm or less.

Hereinafter, the present invention will be specifically explained using examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

/ compound, triphenylamine compound, bisazo compound, and perylene compound.

1 copy in each example is a limited quantity of 1 copy without any special terms.
shows.

〔Example〕

7 Talodinitrile 4C1 and titanium tetrachloride 18. ? and α
-Chloronaphthalene 500- was mixed under nitrogen stream for 24 hours.
The reaction was completed by heating and stirring at 0 to 250°C for 3 hours, and then filtered to obtain the product dichlorotitanium phthalocyanine. A mixture of the obtained dichlorotitanium 7 talocyanine and concentrated aqueous ammonia 30011-1 was added to 1
The mixture was heated under reflux for a period of time to obtain the desired product, titanyl phthalocyanine IE. The product was thoroughly washed with acetone using a Soxhlet extractor.

Mass spectrometry analysis of this product revealed that the main component was titanyl phthalocyanine (M, 576) and a small amount of chlorinated titanyl phthalocyanine (M, 610). Form titanyl phthalocyanine (5 parts)
was ground for 64 hours in a ball mill using alumina pieces (60 parts). 3 parts of the micronized titanyl phthalocyanine, saturated polyester resin (1 Vyron 200)
■1 part of Toyobo) and 210 parts of chloroform were mixed in a nine-ball mill using an alumina piece for 18 hours, and the resulting dispersion was applied onto an aluminum-deposited polyester film using a wire bar to generate a charge with a dry film thickness of 0.5μ. A layer was formed. On this charge generation layer, a charge transfer material AT-
16 (5 parts), polycarbonate resin (1 pan-rye) -
A solution of 5 parts of 1250WJ (manufactured by Teidai Kasei ■) dissolved in 65 parts of chloroform was applied with a wire bar to a dry film thickness of 10.
A charge transfer layer of μ was formed, and the sensitivity of the photoreceptor was measured using a Paper Analyzer-5P-4284 (manufactured by Kawaguchi Electric Seisakusho Co., Ltd.).
The sample was charged by corona discharge, the initial potential (Vo) was measured, and then it was left in a dark place for 10 seconds, and the surface potential retention rate (■1°/V0) after 10 seconds was measured. Next, light was irradiated from a tungsten lamp at a surface illuminance of 5 lux.
Photosensitivity E and E were measured by measuring the time taken for the surface potential to decrease.

In addition, the surface potential (V) 15 seconds after the start of exposure was also measured in the same manner.

Further, the light is split into 850 nm (light intensity 10mv/*
”) was incident and measured, and the photosensitivity (E, i) was similarly measured.

The spectral sensitivity of this photoreceptor is 520 to 9 as shown in Figure 4.
Practical sensitivity of photoreceptor for laser printer in wide range of 00 nm E% = 10 erg/cW? (E% = α
1 cm”/erg).

In addition, the same paint as in Example 1 was applied onto a transparent PET film, and the measured visible absorption spectrum is shown in FIG.

Thus, it exhibits maximum absorption at 650 nm and 800 nm. Also.

FIG. 2 is an X-ray diffraction diagram of this paint.

Practical Example 24 1 part of finely divided titanyl phthalocyanine obtained by grinding the α-type titanyl phthalocyanine obtained in the above I in the same manner as in Example 1 was dissolved in 0 parts of concentrated sulfuric acid while maintaining the temperature at 5°C, and then dissolved for 2 hours. Continue stirring at step 9. This solution was gradually dropped into 200 parts of ice water, stirred, and the precipitate was thoroughly washed with distilled water.

(The X-ray diffraction pattern of the α-type titanyl phthalocyanine thus obtained is shown in Figure 1 (C).) After milling for 20 hours in a ball mill using this titanium 7-talocyanine t-alumina powder, the A composite electrophotographic photoreceptor was prepared in the same manner as in Example 1, and the characteristics of the photoreceptor were measured in the same manner as above.

Comparative Example 1 The titanyl phthalocyanine obtained in 1 above was converted into α-chlorot7
A single-layer electrophotographic photoreceptor was prepared in the same manner as in Example 1 using β-type titanyl phthalocyanine obtained by recrystallization and purification using talene, and the characteristics of the photoreceptor were measured in the same manner as before. did.

Example 6 Charge transfer substance AT-16 (8 parts), polyarylate resin (rU 100J manufactured by Union Carbide) (8 parts)%
A solution consisting of 92 parts of dioxane and 92 parts of dioxane is applied to a dry film thickness of 10 μm. On top of that, 3 parts of finely divided titanyl phthalocyanine obtained in the same manner as in Example 1, a charge generating substance AP-53 (1 part), a charge transfer substance/l6T-1
6 (6 parts), polyarylate resin rU 100'' (15
150 parts of chloroform) and 150 parts of chloroform were mixed in a T-paint shaker and applied to a dry film thickness of 5 μm to prepare a composite electrophotographic photoreceptor, and the photoreceptor characteristics were measured and summarized in Table 6. The photoreceptor characteristics of Examples 1 to 6 and Comparative Example 1 are summarized in Table 6.

Examples 4 to 7 Hiroyuki 1 8 to 14 6 parts of finely divided titanyl phthalocyanine obtained in the same manner as in Example 1, saturated polyester resin ([Vylon 200
1 part of "Toyo Visit to England" and 210 parts of each milling medium listed in Table 7 below were mixed for 18 hours in a ball mill using alumina peas, and the resulting dispersion was coated on an all-aluminum deposited polyester film using a wire bar. A charge generation layer having a dry film thickness Q of 3 μm was formed. Hereinafter, a composite electrophotographic photoreceptor was prepared in the same manner as in Example 1, and the sensitivity (E) of the photoreceptor was measured by inputting 830 nm light (light intensity 10'' W/L). The results are summarized in Table 7.

(J-1) In Example 1, various photoreceptors were prepared using other charge transfer substances shown in Table 8 in place of the charge transfer substance AiT-16, and spectroscopy was performed at 830 nm. light (light intensity 101
Measure the photoreceptor sensitivity (E) by inputting 1W/El,
The results are summarized in Table 8.

Table 8 Examples 15 to 20 In the photoreceptor of Example 1, the charge generating substance listed in Table 9 was further added in an amount of 50% by weight based on the total titanyl phthalocyanine to prepare various photoreceptors. The characteristics of each photoreceptor are listed in Table 9.

Table 9 [Effects of the Invention] The composite disc electrophotographic photoreceptor of the present invention has a photosensitive layer in which α-type titanyl phthalocyanine is dispersed in a binder. It has high sensitivity and is particularly excellent as a photoreceptor for laser beam printers and liquid crystal printers that use a light source of about 700 to 900 nm.

The composite electrophotographic photoreceptor of the present invention can be used not only for laser beam printers but also for semiconductor lasers, etc.
The present invention can also be applied to various other optical recording devices using a light source.

[Brief explanation of drawings]

Figure 1 including J and ± is Titanyl 7 Tarociani/X#! It is a diffraction diagram. (aJ...X of α-type titanyl phthalocyanine treated with acid paste method
G @el is an enlarged partial sectional view of the electrophotographic photoreceptor according to the present invention. (11-... Conductive support (2)... Titanyl phthalocyanine (3)...
...Binder (41) ...Hole transport material (5) ...Hole transport material (6) ...Charge generating material (Al... ...Charge transport layer (Bl...Charge carrier generation layer FIG. 4 is a diagram showing the spectral sensitivity of the electrophotographic photoreceptor of Example 1. FIG. 5 is a diagram showing the spectral sensitivity of the electrophotographic photoreceptor of Example 1. FIG. 3 is a diagram showing the visible absorption spectrum of the charge generation layer of FIG.

Claims (1)

[Scope of Claims] 1. A composite electrophotographic photoreceptor comprising a photosensitive layer comprising α-type titanyl phthalocyanine dispersed in a binder. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a charge transfer substance. 3. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a charge transfer substance and a charge generation substance. 4. Titanyl phthalocyanine in which α-type titanyl phthalocyanine exhibits strong peaks at each Bragg angle 2θ of 7.5°, 12.3°, 16.3°, 25.3°, and 28.7° in the X-ray diffraction diagram. An electrophotographic photoreceptor according to claim 1. 5. Electrophotographic photosensitive material according to claims 2 to 4, wherein the charge transport substance is at least one compound selected from the group consisting of indoline compounds, quinoline compounds, triphenylamine compounds, and bisazo compounds. body. 6. The electrophotographic photoreceptor according to claims 3 to 4, wherein the charge generating substance is a perylene compound or a bisazo compound.