JPS5865440A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic receptor with high sensitivity and low residual potential by forming a photosensitive layer contg. a carrier generating substance and a triarylamine deriv. as a carrier transferring substance on an electrically conductive support. CONSTITUTION:A photosensitive layer contg. a carrier generating substance and a carrier transferring substance is formed on an electrically conductive support to obtain a separated function type electrophotographic receptor. At this time, a triarylamine deriv. represented by the formula (where each of Ar1 and Ar2 is optionally substituted phenyl; Ar3 is optionally substituted arylene; Ar4 is optionally substituted aryl, furyl or thienyl; and one or more among alkyl, alkoxy, aryloxy, OH and halogen are combinedly used as each substituent) is added as the carrier transferring substance. Since the triarlamine deriv. has no film forming capacity, when the photosensitive layer is formed using the deriv., it is preferable to use the deriv. together with a binder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly to a novel electrophotographic photoreceptor having a photosensitive layer containing a carrier-generating substance and a carrier-transporting substance.

Conventionally, electrophotographic photoreceptors having a photosensitive layer containing as a main component an inorganic leading conductor such as selenium, zinc oxide, or cadmium sulfide have been widely known. However, these are not necessarily satisfactory in terms of properties such as thermal stability and durability, and furthermore, there are problems in manufacturing and handling due to toxicity.

On the other hand, electrophotographic photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component are relatively easy to manufacture, inexpensive, and easy to handle, and generally compared to selenium photoreceptors. It has many advantages, including excellent thermal stability, and has attracted a lot of attention in recent years. Poly-N-vinylcarbazole is the most well-known such organic photoconductive compound, and 2.4.7-
) 2) Electrophotographic photoreceptors having a photosensitive layer containing as a main component a charge transfer complex formed from a Lewis acid such as 0-9-fluorenone have already been put to practical use.

On the other hand, electrophotographic photoreceptors are known that have a laminated type or dispersion type functionally separated photosensitive layer in which the carrier generation function and the carrier transport function of the photoconductor are assigned to separate substances, respectively. Electrophotographic photoreceptors having a photosensitive layer consisting of a carrier generation layer consisting of a thin layer of amorphous selenium and a carrier transport layer containing poly-N-vinylcarbazole as a main component have already been put into practical use.

However, since poly-N-vinylcarbazole lacks flexibility, its coating is hard and brittle and prone to cracking and peeling. Therefore, electrophotographic photoreceptors using it have poor durability. In addition, if a plasticizer is added to improve this drawback, the residual potential will increase when subjected to the electrophotographic process, and as it is repeatedly used, the residual potential will accumulate and gradually cause fog on the side of the copy. It has a drawback that K occurs.

In addition, since low-molecular organic photoconductive compounds generally do not have film-forming ability, they are used in combination with any binder, and therefore, by selecting the type and composition ratio of the binder used, Although this is preferable in that it is possible to control the physical properties of the film or the electrophotographic properties to a certain degree, the types of organic photoconductive compounds that are highly compatible with binders are limited, and in reality The reality is that there are not many materials that can be used in the construction of the photosensitive layer of an electrophotographic photoreceptor.

For example, 2,5-bis(p-diethylaminophenyl')-1,3,4-oxadiazole described in U.S. Pat. Since the material has low compatibility with binders that are usually preferably used, it can be mixed with a binder such as polyester or polycarbonate in the ratio required to obtain favorable electrophotographic properties and then exposed to light. If a layer is formed, oxa-diazole crystals will precipitate at a temperature of 50'C or higher, resulting in a disadvantage that electrophotographic properties such as charge retention and sensitivity deteriorate.

On the other hand, the diarylalkane rust conductor described in U.S. Pat. When this is used in the construction of a photosensitive layer of a photoreceptor for repetitive transfer type electrophotography in which charging and exposure are repeated, it has the disadvantage that the sensitivity of the photosensitive layer gradually decreases.

The reality is that a carrier transporting material having practically preferable characteristics for producing an electrophotographic photoreceptor has not yet been found.

An object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity and low residual potential.

Another object of the present invention is to reduce fatigue deterioration due to repeated use and maintain stable characteristics for a long time when used as a photoreceptor for electrophotography of a repetitive transfer type in which charging, exposure, development, and transfer steps are repeated. The object of the present invention is to provide an electrophotographic photoreceptor having excellent durability and having Kl.

As a result of intensive research to achieve the first objective, the inventors of the present invention have found that the objective can be achieved by using a specific triaryluene derivative as a carrier transport material for a functionally separated photoreceptor. They discovered this and completed the present invention. 1. The above object can be achieved by using a triarylure derivative represented by the following general formula as a carrier transporting material constituting a functionally separated photoreceptor.

In the general formula, Ar, , Ar, may be the same or different,
Each represents a substituted or unsubstituted phenyl group.

Ars represents a substituted or unsubstituted arylene group.

Ar represents a substituted or unsubstituted aryl group, furyl group, or chenyl group, and substituents include an alkyl group, an alkoxy group,
One or more of the group consisting of an aryloxy group, a hydroxyl group, and a halogen atom are used in combination.

Preferred substituents for Ar8, kr@, and Ar include halo'I'7fK, substituted/unsubstituted alkyl groups, alkoxy groups, substituted/unsubstituted amino groups, hydroxyl groups, and aryoloxy groups.

That is, in the present invention, the carrier transport ability of the triarylamine derivative represented by the above general formula is utilized, and this is used as a carrier in the photosensitive layer of a so-called functionally separated photoreceptor in which carrier generation and transport are performed using separate substances. When used as a transport material, it has excellent film properties, and has excellent electrophotographic properties such as charge retention, sensitivity, and residual potential.
It is possible to produce an electrophotographic photoreceptor that exhibits stable characteristics because K has little fatigue deterioration when used repeatedly, and the above-mentioned characteristics do not change.

Specific examples of the triarylamine derivatives represented by the above general formula that are effective in the present invention include those having the following structural formula, but are not limited to these and are not limited to φ.

Exemplary Compounds The above-mentioned triaryluacone derivatives can be easily synthesized by known methods. For example, Orgmi
c Reactions vol, 23 p, 73
(John Wiley4Sons, Inc.
), an aromatic aldehyde represented by the following general formula (II) and a dialkyl phosphonate represented by the following general formula (8) are combined with *mm sodium sodium alkoxide sodium such as N,N-dimethylformamide. It can be easily obtained by condensation in the presence of a hydride base.

Here Mr3, Mryuki, Ar, , person r4i! The formula CI
) The same expression as Km ke, R□ represents an alkyl group or an aryl group.

Next, a typical method for synthesizing triarylamine derivatives used in Kihatsu flll will be specifically explained.

Synthesis Example 1 (Synthesis of Exemplified Compound (6)) Diethyl p-methoxybenzylphosphonate 5.2N (0.02nol
) to N,N-dimethylho & ATt dolo 0dK11jl
llt, Sodium methoxide 12II while cooling on ice.
(0,04 mole) wo711 < le.

4-(p,p'-Ditolylamino)benzaldehyde 61 (0,02 mole) was added dropwise to N, N-a)) 1f Leh7i)'40MIK@ 111 solution, and after the dropwise addition, the mixture was further cooled with ice. Stir for 1 hour. After leaving it at +1 temperature overnight, add 40° of ice water, filter the precipitated crystals, and dilute with acetonitrile at 21°C. ! recrystallize. 'Station amount 6.3 # (71LO) Melting point 155-156℃ Synthesis Example 2 (Synthesis of Exemplary Compound A -+5) Diethyl p-methylbenzylphosphonate s, sl (0, OllSm
ole ) in N,N-dimethylformad 10-, and added sodium methoxide L,Sl while cooling on ice.
(0.03 mole) Woka Fj;, .

4-(p,p'-ditolylamino)benzaldehyde 4JJF(0,01!Sm5lt)&N,N-S)
Add dropwise a solution containing 301 uKl of fh*leb7mid, and after the dropwise addition, stir for an additional 1 hour while cooling on ice. After standing overnight at room temperature, 10 ml of ice water was added to filter out the precipitated crystals, and recrystallized twice with acetonitrile.

Yield: 48JF (829Is) Melting point: 132 to 133°C Examples include inorganic photoconductors such as alloys and amorphous silicon, and organic dyes and pigments that have carrier-generating ability. Particularly preferred organic dyes/pigments include polycyclic quinone pigments and azo dyes such as monoazo dyes, bisazo dyes, and trisazo dyes.

Since the triaryluaelectron derivative of the present invention does not have an I[forming part], when it is used to form a photosensitive layer, it is preferably used together with a binder. , is a hydrophobic, electrically insulating, 74 lume-forming polymer with a high electric potential. Examples of such polymers include the following.

B - (1) Polystyrene B - (2) Polyvinyl chloride B - (3) Polyvinylidene chloride B - (4)
Polyvinyl acetate B-(5) Acrylic resin B-(6) Methacrylic resin B-(7) Polyester B-(8) Polycarbonate B-(9) Phenol formaldehyde resin These binders may be used alone or in combination of two or more. At least i
Although it is used as a copolymer containing more than one species, the binder used in the present invention is not limited to these.

The photoreceptor of the present invention is formed by forming a carrier generation layer 2 on a conductive support via an intermediate layer 5 as required, as shown in FIGS. A photoreceptor having the best electrophotographic properties can be obtained when the carrier transport layer 113 is provided adjacent to the layer 113 and the photosensitive layer is composed of two layers.As shown in FIG. 5 and 1116rllllK, a conductive support! A photoreceptor in which fine particles 7 of a carrier-generating substance are dispersed in a photosensitive IIS containing a carrier-transporting substance as a main component via an intermediate 1I5 if necessary can also be effectively used in the present invention.

Carrier generation occurs when photosensitive #4 is made into a two-layer structure using a process.
Which of the I2 and the carrier transport layer 3 should be the upper layer is determined by K, whether the charging polarity is positive or polar.

That is, when used in a negatively charged state, it is advantageous to use the carrier transport layer 3 as an upper layer, because the triaryl derivative of the present invention in the carrier transport layer has a high transport ability for holes. This is because it is a substance that has

Further, a carrier generation layer 2 constituting a photosensitive layer 4 having a two-layer structure
is a conductive support! Alternatively, it can be formed directly on the carrier transport layer 3, or after providing an intermediate layer such as an adhesive layer or a barrier layer as required, by the following method.

(C-z) Vacuum evaporation method (C-2) Method of dissolving the carrier-generating substance in a suitable solvent and applying it (C-3) Dispersing the carrier-generating substance with a ball mill, homomixer, sand mill, or colloidal I/1 IVC Inside, it is made into fine particles,
A method of applying a dispersion obtained by mixing and dispersing with a binder as necessary. The thickness of the carrier generation layer 2 formed in this way is 0.
．． It is preferably 0.1 to 5 microns, more preferably 0.05 to 3 microns.

Further, the thickness of the carrier transport layer 3 can be changed as necessary, but it is usually preferably 5 to 30 mm thick. The composition ratio in this carrier transport layer 3 is preferably 0.8 to 10 parts by weight of the binder per 1 part by weight of the carrier transport material containing the triarylamine derivative as the main component. When forming the photosensitive layer 4 in which a fine powder carrier-generating substance is dispersed, it is preferable to use the binder in an amount of 5 parts by weight or less per 1 part by weight of the carrier-generating substance. Further, when the carrier generation layer 2 is configured as a dispersed layer using a binder, it is preferable to use the binder in an amount of 5 parts by weight or less per 1 part by weight of the carrier-generating substance.

The conductive support 1 used in the construction of the electrophotographic photoreceptor of the present invention may be a metal plate, or a conductive compound such as a conductive polymer or indium oxide, or a thin metal 1 such as aluminum, palladium, or gold. Paper, plastic film, etc. that have been made conductive by coating, vapor deposition, or lamination are used. The intermediate layer 5, such as the J1 adhesion layer or barrier layer, may include organic materials such as gelatin, casein, starch, polyvinyl alcohol, vinyl acetate, ethyl cellulose, and carbo-Φ dimethyl cellulose, in addition to the high G polymer used as the binder. Polymer compounds or aluminum oxide are used (1).

The electrophotographic photoreceptor of the present invention has the above-mentioned structure, and as is clear from the examples described later, it has excellent charging characteristics, sensitivity characteristics, and high stability characteristics.

Examples of the present invention will be specifically described below, but the embodiments of the present invention are not limited thereto.

Example 1 Selenium was vapor-deposited on a conductive support made of aluminum foil laminated on a polyester film to a thickness of 0.
A carrier generation layer of 5 microns was formed. 1 on top of that
6 parts by weight of the exemplified compound (t) and 10 parts by weight of polycarbonate "Panlite L-1250J (manufactured by Shoiri Kasei Co., Ltd.) were neutralized and dissolved in 1 sl. parts by weight of 1,2-dichloroethane, and after drying ** A carrier transport layer was formed by applying the carrier transport layer to a film thickness of 11 cm, thereby completing the electrophotographic photoreceptor of the present invention.

This electrophotographic photoreceptor was tested using an electrostatic copying paper tester "8".
The electrophotographic characteristics were measured using the Guinaoc method using F-428111J (II) (newly manufactured by Kawaguchi Denki Seisaku).

That is, the surface of the photosensitive layer of the photoreceptor was charged with a charging voltage of -6 KV.
The surface potential when charged for seconds Vm1, then the exposure amount required to attenuate by half (half-reduced exposure amount) E% (lu
x @ @ec ) line K 30 lux e sec
Surface potential (residual potential) after irradiation with an exposure amount of Vm
were calculated respectively. The same measurement was repeated 100 times.

The results are shown in Table 1.

Table 1 As is clear from this table, the electrophotographic photoreceptor of the present invention has sufficient charge retention ability, high sensitivity, low residual potential, and maintains good characteristics even after repeated use #I. It has excellent properties as a photographic photoreceptor.

Comparative Example 1 Exemplary compound as a carrier transport substance (9-(p-diethyla5-nostyryl) having the following structural formula in place of 11)
A comparative photoreceptor was prepared in the same manner as in Example 1 except that anthracene was used. When this photoreceptor was measured in the same manner as in Example 1, the results shown in Table 2 were obtained.

w42 As is clear from the results in the table above, the comparative photoreceptor was significantly inferior to the photoreceptor of the present invention in Example 1 in terms of sensitivity and stability during repeated use.

Examples 2 to 4 An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1, except that exemplified compounds (2), (3), and (4) were used instead of exemplified compound (1) as carrier transport substances. It was created.

When these photoreceptors were pressed in the same manner as in Example 1 and their initial characteristics were measured, the results shown in Table IIE3 were obtained.

tR3 Table Example 5 A conductive support consisting of a polyester film coated with 11 pieces of aluminum was coated with a 0.0mm thick polyester film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-10J (manufactured by Kensui Kagaku Co., Ltd.)". 05 micron intermediate 111 is placed on top of it.
1 part by weight of J (C,1,A 59300 manufactured by ICI) was added to a weighted part of 1,2-dichloroethane and dispersed in a ball mill. Polycarbonate "Panlite L-1250J (manufactured by Senjin Kasei Co., Ltd.) was added to the dispersion obtained. ), 1.5 parts by weight of the carrier-generating layer was formed by dissolving 1.5 parts by weight, thoroughly mixing the coating solution, and applying the coating solution to a dry film thickness of 2 microns.

On top of that, 6 parts by weight of exemplified compound (5) and 10 parts by weight of polyester [Pylon 200J (manufactured by Toyobo Co., Ltd.) were added.
．． A carrier transport layer was formed by coating a coating solution dissolved in 9 parts by weight of 2-dichloroethane so that the film thickness after drying was 10</0 nm, thereby forming an electrophotographic photoreceptor of the present invention. When this photoreceptor was measured in the same manner as in Example 1, the results were as follows.

Table 4 Comparative Example 2 A comparative photoreceptor was prepared in the same manner as in Example 5, except that a carbazole derivative having the following structural formula was used instead of Exemplary Compound (5) as a carrier transport material.

When this comparative photoreceptor was measured in the same manner as in Example IK, the results shown in Table 5 were obtained.

As is clear from the results in Table 5, the comparative photoreceptor was significantly inferior to the photoreceptor of the present invention in terms of sensitivity and repeated stability.

Example 6 An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example S except that dibromoviolanthrone represented by the following structural formula was used instead of dibromoanthrone as a carrier generating substance. The initial characteristics of this photoreceptor were measured in the same manner as in *mst, and Vm=-
932V, BH=3, g 1sax@gentc, V
l = OV.

In addition, this photoreceptor was used in an electrophotographic copying machine [[J-Bix200
When I installed the 0RJ (manufactured by Koga Roku Shashin Kogyo Co., Ltd.) and conducted a live-action test, I received a copy that was faithful to the original, had high contrast, excellent gradation, and was clear.

Even if this was repeated too many times, it was still the same as the initial one (・It gave a good copying quality.

Example 7 The intermediate layer used in Example 5 was provided on a conductive support made of aluminum foil laminated on a polyester film. On top of that, the suazo pigment 1 is represented by the following structural formula:
A carrier-generating layer was formed by dissolving 100 parts by weight of ethylenediamine and applying the solution to a dry film thickness tJi of 9.5 microns. Furthermore, exemplified compounds (
6) 6 parts by weight and polycarbonate “Kneepilon S・-1”
000'' (manufactured by Mitsubishi Gas Chemical Co., Ltd.) 10 parts by weight and 1,2-
An electrophotographic photoreceptor of the present invention was prepared by forming a carrier transport layer by coating a solution dissolved in 3 parts by weight of dichloroethane so that the film thickness after drying was 15 cm. This photoreceptor was measured in the same manner as in Example LK, and the results shown in Table 6 were obtained.

w4@Table As is clear from the results, the photoreceptor of the present invention is extremely excellent in sensitivity and repeated stability.

Example 8 Boriemethel "Iron 200J" was applied on a conductive support made of a polyester film laminated with aluminum film.
(manufactured by Toyobo Co., Ltd.) with a thickness of 0.1 micron.

As the hK carrier generating substance, 1 part by weight of bisazo pigment represented by the following structural formula was added to 1,2-dichloro-1220
A carrier-generating layer was formed by applying a liquid dispersed in parts by weight to a dry film thickness of 0.3 fcm. Furthermore, 6 parts by weight of exemplified compound (7) and polycarbonate are added thereon.
[Panlight L-1260J (manufactured by Shoiri Kasei Co., Ltd.) 10
A carrier transport layer was formed by dissolving 1.2-dichloroethane in 1.2-dichloroethane parts by weight to form a carrier transport layer, and an electrophotographic photoreceptor of the present invention was prepared. The initial characteristics of this photoreceptor were measured in the same manner as in Example 1. VA = -10g10V,
1% = 1.41ux-sec, VR=O
It was V.

This photoreceptor was also used in the electrophotographic copying machine "U-Bix2000".
When the RJ (manufactured by Konishi Roku Photo Industry Co., Ltd.) K was installed and a live copy test was conducted, a copy image with high contrast, excellent gradation, and clearness was obtained with the original WiK**.

Even after repeating this 1,000 times, I was able to obtain a copy of the painting that was as mournful as it was in the beginning.

Example 9 An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 8 except that a bisazo pigment represented by the following structural formula was used as a carrier generating substance.

The initial characteristics of this photoreceptor are Vm=-ttzov, R)f
=2.11ux*sec, Vl = OV and ivy. This was transferred to the electrophotographic copying machine “U-Bix 200oRJ (
(manufactured by Konishiroku Photo Industry Co., Ltd.) and conducted a live-action test 1
Mourning close-up shot that remains the same as the beginning even after 000 repetitions II
I got mine.

Example 10 An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 8 except that a bisazo pigment represented by the following structural formula was used as a carrier generating substance.

The initial characteristics of this photoreceptor are Vm: -98+SV, E
34 =141uxei@c, V* = ov
-c was there. This is an electrophotographic copying machine "U-Bix 20".
00RJ (manufactured by Konishiroku Photo Industry Co., Ltd.) and a live copying test was carried out. Even after repeating 1000 times, a good copy I&I image was obtained which was the same as the initial one.

[Brief explanation of the drawing]

FIGS. 1 to 6 each represent an @ side view showing an example of the mechanical structure of the electrophotographic photoreceptor of the present invention. l... Conductive support 2... Carrier generation layer 3... Carrier transport layer 4...
- Photosensitive layer 5... Intermediate layer 6... Layer 7 containing a carrier transport substance...
... Carrier-generating substance agent Yoshimi Kuwahara Procedural amendment written in November 1982) J22 L, 1 Commissioner of the Japan Patent Office Kazuo Wakasugi 1, patent application No. 148346 2 Invention Name: Electrophotographic photoreceptor:) Relationship with the Soup Incident in Supplement 2 Patent Applicant Address: 26th, Nishi-Shinjuku IJ, Shinjuku-ku, Tokyo, 2nd Name
Name (1271 Roku Konishi Photo Co., Ltd. Representative Director Kawa
Nobuhiko Moto 4 Agent 191 Katsujo East 5 To II 'j Jf City Sakura-cho 1 City Area Konishi Rokusha 9 "L Chogyo Co., Ltd. 1 Spontaneous 6, Subject of amendment @Details of the invention" in the specification 7. Contents of the amendment The detailed explanation of the invention is amended as follows. Page 7 #I Delete lines 1 to 12 and insert the following sentence. rArl and r may each be the same or different, and represent a substituted or unsubstituted phenyl group. Arc represents a substituted or unsubstituted arylene group. Preferably used arylene groups are phenyl group and naphthylene group. ◎ Mr represents a substituted or unsubstituted aryl group, a substituted or unsubstituted 7lyl group, or a substituted or unsubstituted chenyl group. Preferred aryl groups include phenyl, naphthyl, and anthryl groups. Preferred substituents for the groups of mrl, mrl, and mr include halogen atoms, substituted or unsubstituted alkyl groups, alkoxy groups, substituted or unsubstituted amine groups, hydroxyl groups, and aryloxy groups. They may be used differently or the same. The basis of Ar4! Preferred substituents for replacing IC1f include alkyl groups, alkoxy groups, aryloxy groups, hydroxyl groups,
Heloge/atom is used. ”

Claims (2)

[Claims] (1) In a functional separation layer electrophotographic photoreceptor in which a photosensitive layer containing a carrier-generating substance and a carrier-transporting substance is provided on a conductive support, a triaryl represented by the following general formula CI) is used as the carrier-transporting substance. 1. An electrophotographic photoreceptor characterized by containing a sulfur derivative. General formula CI) (However, in the formula, Ar, Ar, which may be the same or different, represents a substituted or unsubstituted phenyl group, Ar represents a substituted or unsubstituted 7-arylene group, and Ar4 represents a substituted or unsubstituted phenyl group. Substituted aryl group, heptalyl group, chenyl group, etc. As a substituent, one or more from the group consisting of an alkyl group, an alkoxy group, an aryloxy group, a hydroxyl group, and a halogen atom are used in combination.) (2) The photosensitive layer contains a carrier-generating layer containing a carrier-generating substance and a carrier-transporting substance.
The electrophotographic photoreceptor according to claim 1, which is constituted by a laminate including a carrier wheel transport layer.