JPS6314154A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve responsiveness to light by constituting an electric charge generating layer of a specific chloroindium phthalocyanine and an electric charge transfer layer of specific 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethy laminophenyl)-pyrazoline. CONSTITUTION:The electric charge generating layer is constituted of the chloroindium phthalocyanine expressed by formula I and the electric charge transfer layer is constituted of the 1-phenyl-3-(p-diethylaminostyryl)-5-(p-di ethylaminophenyl)-pyrazoline expressed by formula II. Then, the chloroindium phthalocyanine has high sensitivity to light of a near IR region of >=750nm wavelength even if said phthalocyanine is not subjected to a solvent vapor treatment or heat treatment, etc.; therefore, electric charge carriers are efficient ly generated by the output light from a semiconductor laser of, for example, about 800nm oscillation wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) This invention relates to an electrophotographic photoreceptor, particularly 750
The present invention relates to a functionally separated electrophotographic photoreceptor that exhibits high sensitivity to light in a wavelength range of nm or more and has a fast photoresponse speed.

(Prior Art) Electrophotographic photoreceptors are described in many documents including Japanese Patent Application Laid-open No. 57-146255, and among them, a conductive support as shown in cross section in FIG. 1
It has already been recognized that a functionally separated type (laminated type) type in which a charge generation layer 13 and a charge transport layer 15 are sequentially provided on the upper side of the layer 1 is useful.

In such an electrophotographic photoreceptor, the conductive support 1
1 is made of a suitable material, such as aluminum, for example. The charge generation layer 13 can be formed by vacuum evaporating the charge generation material on the above-mentioned conductive support 11, or by applying a solvent in which the charge generation material is dispersed onto the support and drying it, or by drying the charge generation material. This was done by applying a solution in which the generated material and resin were dispersed onto a support and then drying it. Further, the charge transport layer was formed by applying a solution in which a charge transport material and a resin were dispersed onto the charge generation layer and then drying the solution.

Incidentally, in recent years, such electrophotographic photoreceptors have been incorporated into laser beam printers that use laser light as a light source. There is a need for an electrophotographic photoreceptor that has high sensitivity to output light, that is, light with an oscillation wavelength of around 800 nm.

Conventional electrophotographic photoreceptors that can meet this demand and have high sensitivity to light in the near-infrared region with a wavelength of 50 nm or more include metal-free phthalocyanine compounds or metals as the charge generation material of the charge generation layer 13. A phthalocyanine compound is used, and an oxadiazole derivative is used as the charge transport material of the charge transport layer 15 (for example, JP-A-57-
148255), those using pyrazoline derivatives (for example, Japanese Patent Publication No. 54-7580), or those using hydrazone derivatives (for example, JP-A-59-1669).
59 Publication) etc. are known.

Furthermore, in order to obtain satisfactory photoresponsiveness in such a functionally separated electrophotographic photoreceptor, (1) the charge-generating material must efficiently generate charge carriers; Specifically, a phenomenon that is thought to occur in which a charge-generating material absorbs light irradiated onto an electrophotographic photoreceptor and generates charge carriers with the help of an electric field and heat occurs efficiently.

(2) The generated charge carriers cross the energy barrier at the interface between the charge generation layer and the charge transport layer and are efficiently injected into the charge transport material.

(2) The injected charge carriers are efficiently transported through the charge transport material.

It is necessary that each of the following conditions be satisfied, so that the charge on the surface of the portion of the electrophotographic photoreceptor that is irradiated with light is quickly neutralized, that is, it is possible to obtain satisfactory photoresponsiveness.

Regarding the condition (2), it is disclosed that, for example, a titanyl phthalocyanine vapor-deposited film that is subjected to solvent vapor treatment after vapor deposition exhibits satisfactory characteristics even for light in a wavelength range of 750 nm or more (specifically Publication No. 186959/1983). Also, Japanese Patent Application Laid-Open No. 1983-17 related to the applicant of this invention
Japanese Patent No. 4845 discloses that by using a chloroindium phthalocyanine vapor-deposited film as a charge generation layer, satisfactory characteristics can be obtained without subjecting it to solvent vapor treatment. Further, even when a dispersion film of resin and metal phthalocyanine is used, characteristics close to those obtained when using the above-mentioned vapor-deposited film can be obtained.

Condition (2) can be satisfied by forming the charge-generating material with a phthalocyanine compound as described above and forming the charge-transporting material with an oxadiazole derivative, a pyrazoline derivative, a hydrazone derivative, etc. It has achieved excellent characteristics.

(Problems to be Solved by the Invention) However, in a conventional electrophotographic photoreceptor having a charge transport layer configured with a dispersed film containing a resin and a charge transport material, the resin contained in the charge transport layer is Therefore, the distance between each molecule of the charge transport material is thought to be large, and the resin is thought to act as a trap for the charge carriers, resulting in a problem that the mobility of the charge carriers is low.

Therefore, the photoresponsiveness that satisfies the above-mentioned condition (2) is reduced, which is detrimental to high-speed printing in the case of a laser beam printer, for example.

The purpose of this invention is to solve the above-mentioned problems and to
has high sensitivity to light in a wavelength range of m or more, and
The object of the present invention is to provide an electrophotographic photoreceptor having excellent responsiveness to light.

(Means for Solving the Problems) - In order to achieve this objective, the inventor of the present invention conducted various experiments, particularly regarding the following items (1) to (2). The inventors have also discovered that the desired electrophotographic photoreceptor can be obtained by constructing the charge generation layer and the charge transport layer using specific materials, respectively.

(2) Select a charge-generating material that has high sensitivity to light in a wavelength range of 750 nm or more.

(2) In order to ensure that charge carriers are efficiently transported through the charge transport material, the charge transport layer must be composed of only a charge transport material, and a charge transport material that can do this must be selected.

(2) Selecting a combination of a charge generating material and a charge transporting material so that charge carriers can be efficiently injected. In other words, when charge carriers excited by the excitation energy level of the charge-generating material are transferred (injected) to the excitation energy level of the charge-transporting material, matching of mutual levels is a major factor in order to do this efficiently. There is no doubt that this will be the case, but in reality, various characteristics of the charge generation material and charge transport material are involved in this injection property, so it is necessary to determine a compatible combination through trial and error. .

Therefore, the electrophotographic photoreceptor of the present invention is a functionally separated electrophotographic photoreceptor that sequentially comprises a charge generation layer and a charge transport layer on the upper side of a conductive support, in which the charge generation layer is formed by the structural formula (I The charge transport layer is composed of chloroindium phthalocyanine represented by It is characterized by being composed of pyrazoline.

Further, in carrying out the present invention, the charge generation layer described above is constituted by a vapor-deposited film of chloroindium phthalocyanine represented by the aforementioned structural formula (I), and the charge transport layer described above is constituted by a vapor-deposited film of chloroindium phthalocyanine represented by the aforementioned structural formula (II). ) 1-phenyl-3-
It is preferable to use a vapor-deposited film of (p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline.

(Function)' According to such a configuration, chloroindium phthalocyanine can be used at wavelengths of 75 to 50% without solvent vapor treatment or heat treatment.
It has high sensitivity to light in the near-infrared region of 0 nm or more, so for example, if the oscillation wavelength is 800 nm.
Charge carriers are efficiently generated by the output light from the front and rear semiconductor lasers.

In addition, 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline (hereinafter sometimes abbreviated as this substance) can be easily injected with charge carriers from chloroindium phthalocyanine. It is carried out in Furthermore, since this substance can be in a stable amorphous state at room temperature, a uniform thin film of this substance alone can be obtained using, for example, a vacuum evaporation method.

Therefore, it becomes possible to form the charge generation layer and the charge transport layer continuously by means such as vacuum evaporation, thereby simplifying the manufacturing process.

(Examples) Examples of the electrophotographic photoreceptor of the present invention will be described below.

However, although the embodiments of the present invention described below are described using preferable numerical conditions and conditions of the equipment used within the scope of the present invention, these are merely examples of vehicles, and the present invention is limited only to these conditions. It is clear that this is not the case.

The following formula (1) is a structural formula representing chloroindium phthalocyanine constituting the charge generation layer of the electrophotographic photoreceptor of the present invention, and the following formula (II) is a structural formula representing 1-phenyl-phthalocyanine constituting the charge transport layer of the electrophotographic photoreceptor of the present invention. It is a structural formula showing 3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline.

Further, FIG. 1 is a sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention.
A charge generation layer 13 and a charge transport layer 15 are sequentially provided on the upper side. However, it is of course possible to use a photoreceptor in which an undercoat layer is provided between the support 11 and the charge generation layer 13, for example.

First, chloroindium phthalocyanine was formed to a thickness of 0.2 μm on, for example, an aluminum substrate 11 as a support by vacuum evaporation to obtain a charge generation layer 13. In this example, the chloroindium phthalocyanine was deposited at a vacuum level of 10-' Torr and at a temperature of 300 to 400°C in the crucible containing the deposition material.

Subsequently, 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline was formed to a thickness of 10 μm on this charge generation layer 13 without breaking the vacuum of the evaporator. A charge transport layer 15 was obtained. In this example, the vapor deposition of this substance was carried out at a vacuum level of 10-' Torr and at a temperature of 200 to 250°C in a crucible containing the vapor deposition material.

Next, a protective film of, for example, poly-p-xylylene was formed on the charge transport layer Is to a thickness of 0.2 μm on the charge transport layer Is using a thermal CVD method (not shown).

In this way, the electrophotographic photoreceptor of the example was formed.

A chloroindium phthalocyanine vapor-deposited film was formed on an aluminum substrate 11 in the same manner as in the example, and a charge generation layer 13 was formed.
For comparison, 1-phenyl-3-(p-
diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline and polycarbonate at a weight ratio of 0.5:1, dissolved in chloroform and applied onto the charge generation layer 13 by a spin coating method, After that, it was dried at a temperature of 60°C for 2 hours to form a thin film in which resin and charge transport material were dispersed, and the film thickness was 10 μm.
A charge transport layer 15 was obtained. Subsequently, this charge transport layer 15
A protective film was formed thereon in the same manner as in the examples to obtain an electrophotographic photoreceptor of a comparative example.

The electrophotographic photoreceptors of Examples and Comparative Examples were each charged to -400V, and each of these photoreceptors was irradiated with pulsed light with a wavelength of 8001 m to investigate the attenuation of the surface potential of each photoreceptor. .

Figure 2 shows surface potential on the vertical axis and time on the horizontal axis.
It is a light attenuation characteristic curve diagram plotting the surface potential against the elapsed time immediately after pulsed light irradiation. In FIG. 2, the curve indicated by a is the light attenuation characteristic of the photoconductor according to the present invention, and the curve indicated by b is the light attenuation characteristic of a comparative example, that is, a conventional photoconductor.

As can be understood from FIG. 2, the photoresponsiveness of the electrophotographic photoreceptor of the present invention is significantly faster than that of conventional photoreceptors. In other words, it can be inferred that, according to the photoreceptor of the present invention, charge carriers generated in the charge generation layer are rapidly moved to the surface of the photoreceptor when irradiated with a light pulse.

Further, the electrophotographic photoreceptors of Examples and Comparative Examples were each charged to -400V, and the half-life exposure of these photoreceptors when using light with a wavelength of 800 nm was measured. As a result, the half-decrease exposure amount of the photoreceptor of the comparative example was 1 μJ/am', while that of the photoreceptor of the present invention was 0.5 μJ/Cm2.
It turns out that only half the exposure amount is required.

Note that this invention is not limited to the embodiments described above.

For example, chloroindium phthalocyanine and 1-phenyl-3-(p-diethylaminostyryl)-5-(p
-diethylaminophenyl)-pyrazoly can be formed by methods other than vacuum evaporation, such as resistance heating and electron beam methods, as long as they can be formed as individual thin films. .

Further, it is clear that the film forming conditions, film thickness, etc. of each layer described in the examples can be changed depending on the design of the electrophotographic photoreceptor.

(Effects of the Invention) As is clear from the above description, the electrophotographic photoreceptor of the present invention has high sensitivity to light in the wavelength region of 750 nm or more, and has excellent responsiveness to such light. It is something that

Furthermore, thin films of both chloroindium phthalocyanine and 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline used in this photoreceptor can be formed by, for example, a vapor deposition method. It is. Therefore, the photoreceptor can be manufactured through a simpler process than the conventional photoreceptor manufacturing process using a dip coating method or the like. Furthermore, even when forming a charge generation layer and a charge transport layer on a drum-shaped conductive support, it is possible to easily mask areas where these layers are not desired, such as the inner surface area of the drum or the areas at both ends of the drum. You can.

Furthermore, in the case of the dip coating method, the charge generating material and the charge transporting material are often stored in a solution state. In this case, chemical changes occur during storage, making it impossible to form a charge generation layer and a charge transport layer of uniform quality.However, in the case of this invention, both materials are Since the electrophotographic photoreceptor of the present invention can be stored in the same state without causing such problems, it can be said that the electrophotographic photoreceptor of the present invention has great industrial value from the manufacturing point of view.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing electrophotographic photoreceptors of the prior art and the present invention, and FIG. 2 is a characteristic curve diagram showing the light attenuation characteristics of the photoreceptor of the present invention and a photoreceptor of a comparative example. 11... Conductive support (aluminum substrate) 13...
- Charge generation layer (deposited film of chloroindium phthalocyanine) 15... Charge transport layer (deposited film of 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline). Patent Applicant: Oki Electric Industry Co., Ltd. Agent, Patent Attorney: Takayuki Ogaki
:Aiεe month Rimo Aimei Niiika 31
Figure 1 Clear glaze M (Sec) Comparison flight 1 1 x Light 6 ton 9 attenuation characteristics + Characteristics showing raw - Kazoden Figure 2

Claims (2)

[Claims] (1) In a functionally separated electrophotographic photoreceptor that sequentially comprises a charge generation layer and a charge transport layer on the upper side of a conductive support, the charge generation layer is formed of a chloroindium phthalocyanine represented by the following structural formula (I). The charge transport layer is composed of 1-
Phenyl-3-(p-diethylaminostyryl)-5-
An electrophotographic photoreceptor comprising (p-diethylaminophenyl)-pyrazoline. ▲There are mathematical formulas, chemical formulas, tables, etc.▼…(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼…(II) (2) The charge generation layer is constituted by a deposited film of chloroindium phthalocyanine represented by the above structural formula (I), and the charge transport layer is constituted by a 1-phenyl-phthalocyanine represented by the above structural formula (II). 2. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is constructed of a vapor-deposited film of 3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline.