JPH0258065A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the photosensitive and the repeating characteristic of the subject body by incorporating a specified azulenium compd. as an electric charge generating substance in the photosensitive body. CONSTITUTION:The azulenium compd. shown by formula I is incorporated in the photosensitive layer contd. in the monolayer type or the laminated type photosensitive body. In the formula, R1-R3 are each hydrogen or halogen atom or alkyl, R4-R6 are each hydrogen or halogen atom or alkyl, etc., (l) is 0 or 1, (m) is 1-5, X<-> is a pair ion. The concrete example of a compd. shown by the formula is exemplified by a compd. shown by formula II. An electric charge generating substance is preferably composed of the azulenium compd. shown by formula III. In formula III, R1-R5 are each hydrogen or halogen atom, etc., R6 is a group shown by formula IV, etc., R11 is hydrogen or halogen atom, etc., land X<-> is the same meaning to that mentioned above, (m) is 1 or 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor using a novel charge-generating substance.

[Conventional technology]

Conventionally, photosensitive materials for electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) include inorganic photoconductive substances such as selenium or selenium alloys, or inorganic photoconductive substances such as zinc oxide or cadmium sulfide in a resin binder. Dispersed, Po I
Organic photoconductive substances such as J-N-vinylcarbazole or polyvinylanthracene, phthalocyanine compounds, or bisazo compounds dispersed in a resin binder or vacuum-deposited are used. ing.

The photoreceptor also needs to have the function of retaining surface charge in the dark, the function of receiving light and generating charge, and the function of receiving light and transporting charge, but these functions can be achieved in three layers. This is a so-called single-layer photoreceptor, which is laminated with functionally separated layers: a layer that mainly contributes to charge generation, and a layer that contributes to retaining surface charge in the dark and charge transport during light reception. There is a so-called laminated photoreceptor. For example, the Carlson method is applied to image formation by electrophotography using these photoreceptors. Image formation in this method involves charging the photoconductor in a dark place by corona discharge, forming an electrostatic latent image such as text or pictures on the original on the surface of the charged photoconductor, and forming an electrostatic latent image on the surface of the charged photoconductor. After the toner image has been transferred, the photoreceptor is subjected to static electricity removal, removal of residual toner, photostatic static removal, etc. before being reused. be done.

In recent years, electrophotographic photoreceptors using organic materials have been put into practical use due to their advantages such as flexibility, thermal stability, and film-forming properties. For example, BoIJ-N-vinylcarbazole and 2.4.7-t! J nitrofluoren-9-one (described in U.S. Pat. No. 3,484,237), a photoreceptor containing organic pigment as a main component (JP-A-47-37)
543), and a photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (described in JP-A-47-10735). Furthermore, new hydrazone compounds,
Many such compounds, such as disazo compounds, have been put into practical use.

[Problem to be solved by the invention]

As mentioned above, organic materials have many advantages that inorganic materials do not have, but at the same time, there is currently no material that fully satisfies all the characteristics required of electrophotographic photoreceptors. In particular, there were problems with photosensitivity and characteristics during repeated and continuous use.

The present invention has been made in view of the above-mentioned points, and uses a new organic material that has never been used as a charge-generating substance in the photosensitive layer, thereby achieving a copying machine with high sensitivity and excellent repeatability. The purpose of the present invention is to provide an electrophotographic photoreceptor for use in cameras and printers.

[Means to solve the problem]

According to the present invention, the above-mentioned objects are 1) provided with a photosensitive layer 20, 21, 22 containing at least one azulenium compound represented by the general formula (I).

atom, halogen atom or alkyl group, R4, Rs.

R6 is a hydrogen atom, a halogen atom, an alkyl group,
an alkoxy group, a substituted or unsubstituted aryl group or an amino group, l represents 0 or 1, m represents an integer of 1 to 5, and Xe represents a counter ion. )2)-Providing a photosensitive layer 20.21.22 containing at least one azulenium compound represented by (II).

(Here, R,, R,, R3, R, and R9 are
Each is a hydrogen atom, a halogen atom, an alkyl group or an aryl group; In the formula, R+ I+ Rl 2
are a hydrogen atom, a halogen atom, and an alkyl group, respectively.

This is achieved by a substituted or unsubstituted aryl group or amino group, n represents 1 or 2).

The azulenium compounds represented by (I) and (II) used in the present invention can be synthesized by a conventional method. Specific examples of the azulenium compound represented by the general formula (1) thus obtained are as follows.

- Tsuzuriyo (formerly) Examples of azulenium compounds are as follows.

CH.

/′.

The photoreceptor of the present invention contains a compound represented by the general formula ([) or (IT) in the photosensitive layer. It can be used as shown in Figure 3.

1 to 3 are conceptual cross-sectional views of the photoreceptor of the present invention.
20, 21 and 22 are a conductive substrate, 20, 21 and 22 are photosensitive layers, 3 is a charge generating material, 4 is a charge generating layer, 5 is a charge transporting material, 6 is a charge transporting layer, and 7 is a coating layer.

FIG. 1 shows a compound of general formula (1) or (II) as a charge generating substance 3 and a charge transporting substance 5 on a conductive substrate 1.
A photosensitive layer 20 (commonly referred to as a single-layer type photoreceptor) is provided in which the photoreceptor is dispersed in a resin binder.

FIG. 2 shows a charge generation layer 4 containing a compound of general formula (1) or (n) as a charge generation substance 3 on a conductive substrate 1, and a charge transport layer 6 mainly composed of a charge transport substance 5. A photosensitive layer 21 (usually referred to as a contact type photoreceptor) is provided.

FIG. 3 shows an inverse layer configuration to that in FIG.

In this case, a coating layer 7 is further provided to protect the charge generation layer 4, and the photosensitive layer 22 is formed.

The reason for the two types of layer configurations shown in Figures 2 and 3 is that even if the layer configuration shown in Figure 2, which is normally used for a negative charging system, is intended to be used for a positive charging system, there is no compatible charge transport material. This is because the layer structure shown in FIG. 3 is required at the current stage as a positive charging type photoreceptor.

The photoreceptor shown in FIG. 1 can be produced by dispersing a charge generating material in a solution containing a charge transporting material and a resin binder, and applying this dispersion onto a conductive substrate.

The photoreceptor shown in Figure 2 is made by coating a conductive substrate with a dispersion obtained by dispersing particles of a charge-generating substance in a solvent or a resin binder, drying it, and then dissolving a charge-transporting substance and a resin binder thereon. Apply solution.

It can be produced by drying.

The photoreceptor shown in Figure 3 is made by coating a conductive substrate with a solution containing a charge transport substance and a resin binder.

After drying, a dispersion obtained by dispersing charge-generating substance particles in a solvent or resin binder is applied on top.

It can be produced by drying and further forming a covering layer.

The conductive substrate 1 serves as an electrode for the photoreceptor and at the same time serves as a support for other layers, and may be cylindrical, plate-shaped, or film-shaped, and may be made of aluminum, stainless steel, nickel nanometal, etc. Alternatively, it may be made of glass, resin, or the like that has been subjected to conductive treatment.

The charge generation layer 4 is formed by applying a material in which particles of a charge generation substance 3 represented by a compound represented by -Ni) or Nl) are dispersed in a resin binder, and receives light and generates a charge. occurs. In addition to the high charge generation efficiency, the ability to inject the generated charges into the charge transport layer 6 and the coating layer 7 is also important, and it is desirable that the charge is less dependent on the electric field and can be easily injected even in a low electric field. The charge generation layer is mainly composed of a charge generation substance, and a charge transport substance or the like may be added thereto. Resin binders include polycarbonate, polyester, polyamide, polyurethane, vinyl chloride, epoxy, and silicone resin.

Diaryl phthalate resin, polymers and copolymers of methacrylic acid esters, etc. can be used in appropriate combinations.

The charge transport layer 6 is formed by applying a material in which a hydrazone compound, a pyrazoline compound, a stilbene compound, a triphenylamine compound, an oxazole compound, an oxadiazole compound, etc. are dissolved and dispersed as an organic charge transport substance in a resin binder. In the dark, it functions as an insulating layer to hold the charge on the photoreceptor, and when receiving light, it functions to transport the charge injected from the charge generation layer. As the resin binder, polycarbonate, polyester, polyamide polyurethane, epoxy, polymers and copolymers of methacrylic acid ester of phosphoric resin, etc. can be used.

The coating layer 7 has the function of receiving and retaining the charge of corona discharge in a dark place, and has the ability to transmit the light to which the charge generation layer is sensitive, and transmits the light upon exposure, and the charge generation layer It is necessary for the surface charge to be neutralized and annihilated by the injection of the generated charge. As the coating material, organic insulating film-forming materials such as polyester and polyamide can be used. In addition, these organic materials and glass resin, 5
It is also possible to use a mixture of inorganic materials such as i02 and materials that reduce electrical resistance such as metals and metal oxides. The coating material is not limited to organic insulating film forming materials (it is also possible to form inorganic materials such as 5i02, metals, metal oxides, etc. by methods such as vapor deposition and spackling.Coating materials As mentioned above, it is desirable that the material be as transparent as possible in the wavelength region where the light absorption of the charge generating material is maximum.

The thickness of the coating layer itself depends on the composition of the coating layer, but
It can be set arbitrarily within a range that does not cause adverse effects such as an increase in residual potential when used repeatedly and continuously.

[Effect]

There is no known example in which the azulenium compound represented by the above-mentioned binding margin (1) or (II) is used in a photosensitive layer.

In order to achieve the above objective, the present inventors conducted numerous experiments on these azulenium compounds while conducting intensive studies on various organic materials. It has been discovered that the use of a specific azulenium compound represented by the above-mentioned binding margin (1) or (II) as a charge-generating substance is extremely effective in improving electrophotographic properties, and the present invention has been found to have high sensitivity and excellent repeatability. As a result, we were able to obtain a photoreceptor with a unique structure.

〔Example〕

Examples of the present invention will be described below.

Example 1 50 parts by weight of the compound represented by Compound No. 1 was added to polyester resin (trade name: Vylon 200; manufactured by Toyobo) 1
00 parts by weight and 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-2
- Prepare a coating solution by kneading 100 parts by weight of pyrazoline (ASPP) with a tetrahydrofuran (THF) solvent in a mixer for 3 hours, and apply it on an aluminum-deposited polyester film (8R-PET), which is a conductive substrate, using a wire bar method. A photoreceptor was prepared so that the film thickness after drying was 15 μm.

Example 2 100 parts by weight of tf, p-diethylaminobenzaldehyde diphenylhydrazone (ABPH) and polycarbonate resin (trade name Panlite L-1250: Teijin)
A coating solution prepared by dissolving 100 nitride in methylene chloride was applied onto an aluminum-deposited polyester film substrate by a wire bar method to form a charge transport layer so that the film thickness after drying was 15 μm. On the thus obtained charge transport layer, 50 parts by weight of the compound represented by Compound No. 2, 50 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) and THE solvent were kneaded in a mixer for 3 hours. A coating solution was prepared and applied using a wire bar method to form a charge generation layer such that the film thickness after drying was 0.5 μm.

Example 3 In Example 2, the charge transport material was changed to ABP'H, and a stilbene compound, α-phenyl-4.-N
, N-dimethylaminostilbene was used to form a charge transport layer in the same manner as in Example 2, and a charge generation layer was further formed to produce a photoreceptor.

Example 4 In Example 2, the charge transport substance was changed to ABPH and was replaced with a triphenylamine compound, TO! J(p-)I
A charge transport layer was formed using amine in the same manner as in Example 2, and a charge generation layer was further formed to produce a photoreceptor.

Example 5 In Example 2, the charge transport substance was replaced with ABPH and an oxadiazole compound, 2°5-bis(p-
A charge transport layer was formed using (diethylaminophenyl)-1°34-oxadiazole in the same manner as in Example 2, and a charge generation layer was further formed to prepare a photoreceptor.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester R SP-428 manufactured by Kawaguchi Electric.

The surface potential V of the photoreceptor (volts) is +6 in the dark. OK
This is the initial surface potential when corona discharge of V is performed for 10 seconds to positively charge the surface of the photoreceptor, and then the surface potential is V when held in the dark for 2 seconds with corona discharge stopped.
Measure a (volts), then irradiate the surface of the photoreceptor with white light with an illuminance of 2 lux, find the time (seconds) until vd is halved, and calculate the half-attenuation exposure IE, 72 (lux seconds). did. In addition, white light with an illumination intensity of 2 lux is
The surface potential when irradiated for seconds is the residual potential V, (volt)
And so.

Table 1 As seen in Table 1, Example 1, 2.3° 4.5, had good half-attenuation exposure and residual potential.

Example 6 Compound 100 represented by the above compounds Nα3 to Nα28
The weight part is polyester resin (product name: Byron 2).
00) A coating solution was prepared by kneading 100 parts by weight and a THF solvent in a mixer for 3 hours, and the coating solution was coated on an aluminum support to a thickness of about 0.5 μm to form a charge generation layer. An ABPH (7) coating liquid obtained in the same manner as in Example 2 was applied onto this to a thickness of about 15 μm to prepare a photoreceptor.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester rSP-428J manufactured by Kawaguchi Electric. The results are shown in Table 2.

The surface potential Vd (
Measure the Vd and then irradiate the surface of the photoreceptor with white light with an illuminance of 2 Lux to determine the time it takes for VD to be halved (
seconds) was determined and the half-attenuation exposure amount E,/2 (lux/second) was determined.

As seen in Table 2, the azulenium compound Nα
The half-attenuation exposure amount E172 was also good for the photoreceptors using Nos. 3 to 28 as charge generating materials.

Table 2 (Part 1) Table 2 (Part 2) Example 7 50 parts by weight of the compound represented by the compound Nα31 was added to polyester resin (trade name: Vylon 200, manufactured by Toyobo) 1
00ffftaB and 100 parts by weight of 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-2-pyrazoline (A S P P) were kneaded with a tetrahydrofuran (THF) solvent in a mixer for 3 hours. The coating solution was prepared using
Applied by wire bar method, film thickness after drying is 15μm
A photoreceptor was prepared so that

Example 8 First, a coating solution prepared by dissolving 100 parts by weight of p-diethylaminobenzaldehyde-diphenylhydrazone (8BPH) and a polycarbonate resin (trade name Panlite L-1250: Teijin 000 parts by weight in methylene chloride) was applied to aluminum. A charge transport layer was formed by coating on a vapor-deposited polyester film substrate using a wire bar method so that the film thickness after drying was 15 μm.On the thus obtained charge transport layer, the compound represented by Nα32 was applied. 50 parts by weight of the compound, 50 parts by weight of polyester resin (trade name Byron 200, manufactured by Toyobo) and THF solvent were kneaded in a mixer for 3 hours to prepare a coating solution, which was applied using a wire bar method.
A charge generation layer was formed so that the film thickness after drying was 0.5 μm.

Example 9 In Example 8, the charge transport substance was replaced with ABPH, and a stilbene compound, α-phenyl-4·-N,
A charge transport layer was formed using N-dimethylaminostilbene in the same manner as in Example 8, and a charge generation layer was further formed to produce a photoreceptor.

Example 10 In Example 8, the charge transport material was replaced with ABPH and a triphenylamine compound, t'J(p-)I
A charge transport layer was formed using amine in the same manner as in Example 8, and a charge generation layer was further formed to produce a photoreceptor.

Example 11 In Example 8, the charge transport substance was replaced with 8BPH and an oxadiazole compound, 2°5-bis(p-
A charge transport layer was formed using (diethylaminophenyl)-1°3,4-oxadiazole in the same manner as in Example 8, and a charge generation layer was further formed to prepare a photoreceptor.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric.

The surface potential V (volts) of the photoreceptor is +6. Ok
This is the initial surface potential when corona discharge of V is performed for 10 seconds to positively charge the surface of the photoreceptor, and then the surface potential is V when held in the dark for 2 seconds with corona discharge stopped.
, (volts), and then irradiate the surface of the photoreceptor with white light with an illuminance of 2 lux to find the time (seconds) until Vd is halved and find the half-attenuation exposure amount El/2 (lux seconds). And so. Further, the surface potential when white light with an illumination intensity of 2 lux was irradiated for 10 seconds was defined as the residual potential V, (volts).

Table 3 As seen in Table 3, Examples 7, 8, 9゜10.1
Sample No. 1 had good half-attenuation exposure and residual potential.

Example 12 Compound 10 represented by the above compounds Nα33 to N060
0 parts by weight of each were kneaded with 100 parts by weight of polyester resin (trade name Kuilon 200) and THF solvent in a mixer for 3 hours to prepare a coating solution, and coated on an aluminum support to a thickness of about 0.5 μm. Then, a charge generation layer was formed. On top of this, an ABPH coating solution obtained in the same manner as in Example 8 was applied to a thickness of about 15 μm to produce a photoreceptor.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester rSP-428J manufactured by Kawaguchi Electric. The results are shown in Table 4.

The photoreceptor surface is negatively charged by applying -6.0 kV corona discharge to the photoreceptor for 10 seconds in the dark, and then the surface potential vd (
Then, the surface of the photoreceptor was irradiated with white light with an illuminance of 2 lux, and the time (seconds) until Vd was halved was determined, which was defined as half-attenuation exposure IEI/2 (lux seconds).

As seen in Table 4, the azulenium compound No.
, 33 to 60 were used as charge generating materials, and the half-attenuation exposure amount E1i2 was also good.

Table 4 (Part 1) Table 4 (Part 2) [Effects of the Invention] According to the present invention, a compound represented by general formula (1) or (II) is used as a charge generating substance on a conductive substrate. Therefore, a photoreceptor with high sensitivity can be obtained in both positively charged and negatively charged cases.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are schematic cross-sectional views of an electrophotographic photoreceptor according to an embodiment of the present invention. l conductive substrate, 3 charge generation substance, 4 charge generation layer,
5 charge transport material, 6 charge transport layer, 7 coating layer, 20.
21.22 Photosensitive layer.

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one azulenium compound represented by the general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (Here, R_1, R_2, R_3 are hydrogen atoms, halogen atoms, or alkyl groups, respectively, R_4, R_5
, R_6 each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a substituted or unsubstituted aryl group or an amino group, l represents 0 or 1, m represents an integer of 1 to 5, and X^■ represents a counter ion. )2) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one azulenium compound represented by the general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (II) (Here, R_1, R_2, R_3, R_4, and R_5 are hydrogen atoms, halogen atoms, alkyl groups, or aryl groups, respectively, and R_6 is ▲ mathematical formulas, chemical formulas, tables, etc.) ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ l is 0 or 1, m is 1 or 2, X^■ represents a counter ion, and R_1_1, R_1 in the structural formula indicating R_6
_2 is a hydrogen atom, a halogen atom, an alkyl group,
a substituted or unsubstituted aryl group or an amino group; n represents 1 or 2; )