JPS5936253A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To facilitate manufacture and to enhance durability, etc., by incorporating a specified disazo compd. in a charge generating layer in a laminate type electrophotographic receptor obtd. by forming the charge generating layer and a charge transfer layer on a conductive substrate. CONSTITUTION:The charge generating layer is formed by finely pulverizing a disazo compd. represented by the shown formula in which X, Ar are each an optionally substd. aromatic or hetero ring, in a ball mill or the like, dispersing it into a proper solvent, coating the conductive substrate, such as an aluminum or nickel plate, with said dispersion, and drying it. The intended laminate type electrophotographic receptor is obtained by forming a charge transfer layer on this charge generating layer. The disazo compd. of the formula is obtd. by reducing the dinitro group of 2,7-dinitro-9-dicyanomethylenefluorene to the diamino group, diazotizing it, and allowing the obtd. tetrazonium salt to couple with a corresponding coupler, such as naphthol AS.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor for electrophotography, and more specifically, a layer containing a substance that generates charge carriers (hereinafter referred to as a charge-generating substance) when irradiated with light (hereinafter referred to as a charge-generating substance). It is called the generation layer.

), and a layer (hereinafter referred to as charge transport layer) containing a substance (hereinafter referred to as charge transport material) that receives and transports charge carriers generated by the charge generation layer (hereinafter referred to as charge transport layer). Related to electrophotographic photoreceptors.

Conventionally, photoreceptors for electrophotography include inorganic ones that use selenium and its alloys, or photoreceptors that have dye-sensitized zinc oxide dispersed in a binder resin.
In addition, organic substances include 2,4.7-)dinitro-9
-Fluorenone (hereinafter referred to as TNF) and poly-N-
An alternative is one using a charge transfer complex with vinyl carbazole (hereinafter referred to as PVK). However, while these photoreceptors have many advantages, they also have various disadvantages. For example, the currently widely used selenium photoreceptor has difficult manufacturing conditions and high manufacturing costs, is difficult to process into a belt due to its lack of flexibility, and is sensitive to heat and mechanical shock. Care must be taken when handling. Zinc oxide photoreceptors are low in cost because they can be manufactured by spraying inexpensive zinc oxide onto a support, but they generally have low sensitivity, poor surface smoothness, hardness, tensile strength, and scratch resistance. It has mechanical disadvantages such as durability, and as a photoreceptor for plain paper copying machines that is usually used repeatedly, it often has problems with durability. Further, a photoreceptor using a charge transfer complex of TNF and PVK has low sensitivity and is unsuitable as a photoreceptor for high-speed copying machines.

In recent years, extensive research has been carried out to eliminate the drawbacks of these photoreceptors, and in particular, various organic photoreceptors have been proposed. Among them, conventionally, a laminated type photoreceptor has been used, in which a thin film of an organic pigment is deposited on a V'#iL type support (charge generation N), and a layer (%: charge transport layer) mainly composed of a charge transport substance is formed on this layer. Compared to organic photoconductors, they are generally highly sensitive and have stable charging properties, so they are attracting attention as photoconductors for plain paper copiers, and some of them are in practical use. .

Conventional laminated photoreceptors of this type include (1) a thin layer vacuum-deposited perylene derivative as a charge generation layer and an oxadiazole derivative used as a charge transport layer (see U.S. Pat. No. 3,871,882); ), (2) A thin layer formed by coating an organic amine solution of chlordian blue as the charge generation layer and a hydrazone compound used as the charge transport layer (% Journal 55-4238
(see Publication No. 0) are known.

However, it is true that conventional laminated photoreceptors of this type have many advantages, but also have various disadvantages.

The photoreceptor using the perylene derivative and oxadiazole derivative shown in (1) has a high manufacturing cost because its charge generation layer is formed by vacuum deposition.

The photoreceptor using chlordiane blue and hydrazone compound shown in (2) requires the use of an organic amine (e.g. ethylenediamine), which is generally difficult to handle, as a detritus solvent for forming the charge generation layer. There are drawbacks to the above.

In view of the above points, the inventor of the present invention has conducted extensive studies with the aim of developing a laminated photoreceptor that can be easily manufactured and is suitable for repeated use. The present invention was completed based on the finding that a laminated photoreceptor in which a charge generation layer is formed using a substance can achieve the above object.

That is, the electrophotographic photoreceptor of the present invention is a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are provided on a conductive support, in which the charge generation layer has the general formula (1) (wherein, X represents a substituted or unsubstituted aromatic ring, Tortoise represents a heterocycle, and Ar represents a substituted or unsubstituted aromatic ring or heterocycle). General formula (1)
Specific examples of the aromatic ring in X include a benzene ring,
Specific examples of the heterocycle include indole ring, carbazo, 13it, and -<nzofuranhori. Further, specific examples of the aromatic ring in Ar include a benzene ring, a naphthalene salt,
Specific examples of the heterocycle include a dibenzofuran ring and a carbazole ring.

In addition, as the substituent of the above-mentioned mound, a lower alkyl group, a lower alkoxyl group, a dialkylamino group, a halogen, a nitro group, a cyano group, a carxyl group or an ester thereof,
Examples include a halomethyl group, a sulfone group, or a salt or ester thereof.

The laminated photoreceptor of the present invention is easy to manufacture and is excellent as a photoreceptor for copying machines.

The present invention will be explained in more detail below.

First, specific examples of the charge generating substance used in the charge generating layer in the present invention, that is, the disazo compound represented by the general formula (1) above, are as follows.

Among these, a particularly preferable disazo compound is the compound Al
-1, 1-13, 1-15, 1-18, 1-50゜1-
64 etc.

Boiled R, R2H, R.

1-1 -0CR, HHH l-2H-OCH, HH l-3HH-0CHa H l-4-QC, H, HHH l-5H0CzHs HH l-6HH-QC, H Gei H l-7-CH, HHH l -8H-CH, HH l-9HH-CH, H A RHFLY R4R41-
10-C, H, HHH l-11H-C, H, HH l-12HH-C, H, H l-13HHHH 1-14-CI HHH l-15H-CI HH l-16HH-CA H l-17- Br HHHl-18H-Br HHHl-19HH-
Br H l-20-IHHH 1-21H-IHH 1-22HH-IH 1-23-FHHH 1-24H-FHH 1-25HH-FH 1-26-CF, HHH l-27H-CF, HHL-28HH-
CF, H 1-29-CN HHH 1-30H-CN HH 1-31HH-CN HL-32-No, HHH 1-33H-No, HH 1-34HH-No, Hl-35HH-
COOHH l-36HH-COOCtH, H l-3s -OCH, HH-OCH.

1-39 -QC,H,HH-QC,H.

1-40 -CH, HH-CM.

1-41 -ClHH-CI! −
42-CH,HH-C1 1-43-OCH,H-OCH,H l-44-CH3H-CH5H A RI R1RI
R41-45CHm HCl Hl-
46-NoI H-OCH, Hl-47H-OC
H,H-OCH.

1-48 0CH@HHB rl
49 ・CHa H0CHs
Hl-50-0CHs HCI
0CHs1-51 0CHs H0
CHs C11-52HH-8OINa
H l” HH-0C4H1 (tert)
HA A&
A A A-63 Black A The above disazo compound is obtained by reducing 2,7-sinitro-9-dicyanomethylene fluorene to form 2,7-diamitro-9-dicyanomethylene fluorene, and then diazotizing this to form a tetrazonium salt. Then the corresponding Cassirer (naphthol As) and a suitable organic solvent, such as N.

It can be easily produced by reacting with a base in N-dimethylformamide (DMF) to perform a coupling reaction. As an example of this, compound 41
An example of the production of disazo compound No.-13 is shown below. Other disazo compounds can also be prepared in a similar manner to this example.

Production example 9-dicyanomethylene-2,7-sinitrofluorene 1
5.9. An aqueous hydrochloric acid solution prepared by diluting 7 d of 36% hydrochloric acid with 7 ml of water was added to a mixture of 27.5 g of P, iron powder and 500 a of N,N-dimethylformamide. Next, the temperature of the mixture was raised to 80 to 85°C over 1 hour and 30 minutes, and the mixture was further stirred at the same temperature for 2 hours. After cooling, a solution of 3.2 g of sodium hydroxide dissolved in 20 ml of water was added, and then
A small amount of kiso earth was added and filtration was performed. The filtrate was concentrated and the residue was washed 3 times with 500ml of water to obtain 11.4Ii of crude 9-dineanomethylene-2,7-diamifluorene (8
8.1%) was obtained as a greenish-brown powder. Melting point 290℃ or higher.

Next, this crude product was recrystallized from methyl selon rub.
A pure product was obtained as black needle-shaped crystals.

Melting point 290℃ or higher Elemental analysis value (C16H1 (as lN4) calculated value
Actual value 0%? 4.40 74.55 H% 3.90 3.7ON%
21.69 21.49 External ray absorption spec) N
(KBr tablet method) νNH (1st ami 7) 334
0cm-'3430tx'''1 C5-N 2220 cIL-'Next, the diamino compound 1.29 synthesized as above
A mixture of # and 20 dihydrochloric acid, 0.75 mA of sodium nitrite and 10 mA of water! The solution dissolved in
The dropwise addition took 20 minutes at ~7°C. Thereafter, after stirring at about 3°C for 10 minutes, sulfamic acid was added to the reaction mixture to decompose the remaining nitrous acid, and then filtered.

Separately, 2-hydroxy-3-phenylcarbamoylnaphthalene (naphthol As) 2.63 &N,N-
Dissolve in 300 rnl of dimethylformamide,
A diazonium salt bath solution was added to this solution at 10-15°C. Then, add 11.48.9% of sodium acetate to 46.9% of water.
Add the solution dissolved in rnl for 2 minutes at 10-15 °C,
Thereafter, the reaction was completed by stirring at room temperature for 2 hours. A lot of precipitated crystals were collected, 300 ml of N,N-dimethylformamide was added to the crystals, the mixture was heated to 80°C and stirred for 2 hours, and then the crystals were filtered off again. After repeating this operation twice, the crystals were washed twice with 3001 nl of water and dried to obtain a disazo compound of Al-13 as a black-purple powder. Yield: 2.54 fI (diamino compound) 63.0%) original cumulative analysis value (C, oH
,. N, 04) Calculated value Actual value Cchi 74.43 74.13H
3,75 3.68N% 13.89
13.65 Infrared absorption spectrum (KBr tablet method)
νNH (secondary amide) 3250ctn-'ν
C=+N 2225 car-'
νC=0 1675txt-”The present invention uses the above general formula (I
), and the charge transport material used in the charge transport layer is not particularly limited, but typical examples thereof are as follows.

(1) Hydrazone compound R represented by general formula (II) [wherein the tortoise represents a methyl group, ethyl group, 2-hydroxyethyl group, or 2-chloroethyl group, and R2 represents a methyl group, ethyl group, benzyl group] or represents a phenyl group, R3
represents hydrogen, a base, bromine, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a dialkylamino group, or a nitro group. ] (2) General formula (hydrazone compound R (I
ff) [In the formula, Ar represents a naphthalene ring, an anthracene ring, a styryl group, or a substituted product thereof, or a pyridine ring, a furan ring, or a thiophene ring, and R represents an alkyl group having 1 to 4 carbon atoms or a benzyl group. ] (3) Hydrazone compound represented by the general formula [wherein,
R1l R,l R3F R4 represents hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, or a dibenzylamino group, and R6 represents an alkyl group having 1 to 4 carbon atoms, or Encapsulates benzyl group. ] (4) A hydrazone compound represented by the general formula
an alkyl group, an alkoxy group having 1 to 3 carbon atoms, a substituted or unsubstituted dialkylamino group, a dibenzylamino group, or a) ninerogen atom. (5) Diarylmethane compound bounded by the general formula (Vll) [In the formula, R1 represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group, or an a-chain group, and R2s
RII may be the same or different, hydrogen,
It may be an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a chloroalkyl group, or a substituted or unsubstituted aralkyl group, and R2+R3 may be bonded to each other to form a nitrogen-containing heterocycle.

R4s R1 may be the same or different, and each may be hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, or).
Represents Rogen. ] (6) Anthracene compound represented by the general formula (■) [wherein R1 represents hydrogen or a halogen atom, R1 is hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, dialkyl represents an amino group or a substituted or unsubstituted dialkylamino group, R
, represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or a halogen atom. ] (7) Fluorene compound 1 represented by the general formula (■) [
In the formula, horse is hydrogen, halogen/, cyano group, alkoxy group having 1 to 4 carbon atoms, or 1 to n carbon atoms, J Ra I R.
represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted benzyl group, and n
4t g.

represents hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a dialkylamino group. (8) Divinylbenzene compound represented by the general formula (IK) [wherein R is a carbazolyl group, pyridyl group, chenyl group, indolyl group, furyl group, or a substituted or unsubstituted phenyl group, styryl group, or naphthyl group, respectively or an anthryl group, in which these substituents are a dialkylamino group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an acykylamino group, N-alkyl-N-acylkyl Represents a group selected from the group consisting of an amino group and an amine group. ] (9) For pyrazoline compounds represented by the general formula gloss [wherein RI J R1j R3 is hydrogen, carbon number 1 to 4
represents an alkyl group, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group, or a halogen atom, and n represents 0 or 1. ] Specific examples of the above-mentioned charge transporting substances are as follows.

2-1 -CH, -CHaH 2-2-OH, -C, H5H 2-a -CH, -cH (@ H2-4
-CH, Hazu H 2-5-C2H, -CH, H 2-6-C2H, -C2H, H 2-7-C, H, -CH, -@ 512-8-
c2) rll-@H2-9-C2H40H
-CH3H 2-10-C2H40H-C,H,H 2-11-c2H4on -CH,-@
H2-12-C2H4011@H2-13
-C2)]4OA'-CB,
H2-14-C2T (4Ce-C21(, H2-1
5-c2H4cg -CH2@H2-
16-C, H, C1 @ If2-17
-C11S -CI(, -C121
8CH3(4Hs Br2-19
-CH3-C2H50CHs2 20
CH3021(a NOx2-21
-co, -CH2@
-CIjAR+ Ra
Ra2-24 -C, H, -Ck
T, -C12-25-C2H, -CH,-
OCH.

2-26 -CIH, -CHg
-No22-27 -c2n, -cat,
@-C11228C2H@C
Hx-KuomiΣ) -QC,H.

2-29 -c, n, -CII2@
-CH.

230 CtIls CH2@
Br232 C2H4OHCHs
OCgHsZ-33-C21140H-OH, -C,
H.

2-35-(4M40kl C
zHIIBr2 36 C2H4OHCa
l's NOx2-37 -C,H,
OH-CH bar◇ -C,H.

238 C21140HCH40C1H62-
41-C2H, C8-CB5 -C12-
42-CJd4CI Cd(s
=Br2-43-C2114Cg
C11H6NOx2-45-c, H4ci
-@-ocrI.

Ai Ar
R2-52◇%CH2Cf(--CH.

2-55o-C)■2C--〇H3 A6 ΔrR2-61
Minute CH=CH--CH2→size of 101-
■ O〇 - Prisoner's size
pus ■ To ω ri 0 − to
η Size ■---- -He he he he hebe ~ N country country country country country 1) 1) Senkoku 1) country I I 1 1 he he he he prisoner he he he he he he he he he he prisoner he to prisoner to prisoner to prisoner N to prisoner
喤 国 国 閤 agon 国 工 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 国 喤 喤 喤 国 喤 agon existence i:c! 1) 1). Country country country country mi country
) Country 1'1llll I
Il+ 1 to c'I to to to to to to to to to to he to
to country country 1) country agony and country 8 country ■ ■ 0 +-+ to G
豐 slapping C to ~ to prisoner CJ N to prisoner to prisoner to hee to N
to prisoner to to
He he he 閤 閑 工
Place BIli Country Country Country Country Country Emi Kankuni Country Country Mi σ Agony Country!ノ/i
p, rCkI (.

(Space below) ・-409 Country Country 1) Large Country Country Country Country Country Country 1) Country 1) Country Senda C\IC\1Nζslc\1-\1i
NkVb*chi! In addition to the above-mentioned exemplified compounds, polymer substances include poly-N-vinylcarbazole, halogenated poly-N
- Condensation resins such as vinylcarbazole, polyvinylpyrene, bromopyrene-formaldehyde condensation resin, N-ethylcarbasol-formaldehyde condensation resin, and low-molecular substances such as oxazole conductor, oxadiazole 111, and nitro derivatives of fluorenone. Any of the known charge transport materials are effective.

FIG. 1 is an enlarged sectional view of an electrophotographic photoreceptor showing an embodiment of the present invention. This photoreceptor is constructed such that a charge generation layer 22 and a charge transport layer 33 are provided on a conductive support 11 to form a photosensitive layer 44.

Isoelectric supports used in the present invention include metal plates, metal drums, or metal foils made of aluminum, nickel, chromium, etc., and thin layers of aluminum, tin oxide, indium oxide, chromium, and radium metal. For example, paper or plastic film impregnated with a tetraelectric substance may be used.

The charge generation layer is prepared by making fine particles of the specific disazo compound represented by the general formula (I) shown above by means such as a ball mill, and dispersing them in a suitable solvent, or if necessary, adding a binder resin thereto. A dissolved dispersion liquid is coated on a conductive support, and if necessary, the surface is finished by a method such as puff polishing, and the film thickness is adjusted.

The thickness of this charge generation layer is 0.01 to 5 μm, preferably 0.05 to 2 μm, and the proportion of the disazo compound in the charge generation layer is 10 to 100% by weight, preferably 30 to 95% by weight.
Weight%. If the thickness of the i-charge generating layer is 0.01 μm or less, the sensitivity is poor, and if it is 5 μm or more, the potential cannot be maintained. Furthermore, if the proportion of the disazo pigment in the charge generation layer is less than 1 OJti:%, the sensitivity is poor.

The charge transport layer is formed by coating the charge generation layer with a solution prepared by dissolving each of the charge transport substances described above and a binder resin in a suitable solvent such as tetrahydro-7 run. Here, the proportion of the charge transport substance contained in the charge transport layer is 4-110 to 80% by weight, preferably 25 to 75% by weight, and the film thickness is 2 to 100 μm, preferably 15% by weight.
~40 μm. When the proportion of the charge transport substance contained in the charge transport layer is less than 10 wt-m%, the sensitivity is poor, 8
If the amount is more than 0%, the film becomes brittle or the charge transport layer becomes cloudy due to crystal car deposits, which is not preferable. Furthermore, when the thickness of the charge transport layer is less than 5 μm, the retention of t and r is poor;
Above that, the residual potential force becomes high.

The bonding materials for the charge generation layer used here include polyester resin, zotyral resin, ethyl cellulose resin, epoxy resin, acrylic resin,
Examples include vinylidene chloride resin, bonostyrene, polybutadiene, and their copolymers;
smata&'! , used in a mixed state of two or more types.

Also used as binder resins for charge transport layers include polycarbonate, polyester, polystyrene,
Examples include polyurethane, epoxy resin, acrylic resin, silicone resin, and their copolymers.
They may be used alone or in a mixture of two or more.

Furthermore, various additives can be added to the charge transport layer for the purpose of improving flexibility or durability. Examples of additives used for this purpose include halogenated paraffin, dialkyl phthalate, silicone oil, etc. In the photoreceptor of the present invention, if necessary, a barrier layer is provided between the conductive layer and the charge generation layer. An intermediate layer may be provided between the charge transport layer and the charge transport layer, and an overcoat layer may be provided over the charge transport layer.

Further, the disazo compound of the general formula (1) according to the present invention can be used as a dispersed photoreceptor by dispersing it as fine particles in a binder resin (a charge transport substance may be added if necessary). It can also be used.

The structure of the present invention is as described above, and as is clear from the examples described later, the electrophotographic photoreceptor of the present invention is easy to manufacture.
Moreover, it has excellent properties such as stable characteristics even when the photoreceptor is used repeatedly.

EXAMPLES Next, the present invention will be specifically explained using Examples, but the embodiments of the present invention are not limited thereby.

Example 1 76 parts by weight of disazo compound A113, 1260 parts by weight of a solution of polyester resin (Pylon 200 manufactured by Toyobo Co., Ltd.) in tetrahydrone (solid content concentration 2 t), and 3 parts by weight of nat2hydrofuran 3 F00! The IT part was pulverized and mixed in a ball mill, and the resulting dispersion was applied onto the aluminum surface of an aluminum-deposited polyester paste (conductive support) using a doctor blade, and air-dried to a thickness of about 1 line. A charge generation layer was formed.

On the other hand, 2 parts by weight of charge transport substance A2213, polycarbonate resin (Panjiit 1300, Hotaru Jinso Co., Ltd.)
After mixing and dissolving 2 parts by weight and 16 parts by weight of tetrahydrofuran to form a solution, this was spread on the charge generation layer with a doctor blade and dried at 80°C for 2 minutes and then at 100°C for 5 minutes to a thickness of about 20 μm. A charge transfer layer was formed to produce a laminated photoreceptor point 1 shown in FIG.

Examples 2 to 10 Same as Example 1 except that the disazo compound and charge transport substance shown in Table 1 below were used instead of the disazo compound Al-13 and charge transport substance &2-213 used in Example 1. Photoreceptor points 2 to 10 were created in the same manner.

For these photoreceptor points 1 to 10, -
After performing a 6KV corona discharge for 20 seconds to make it negatively charged, it was left in a dark place for 20 seconds, and the surface potential Vpo at that time was
(V), then irradiate the surface with light using a tungsten lamp at an illuminance of 4.5/l/tx, find the time (seconds) until the surface potential reaches % of Vpo, and then expose The amount E% (lux seconds) was calculated. The results are shown in Table-1.

Table 1 In addition, the photoconductor A1 of the present invention was installed in a copying machine Ricobee P-500 manufactured by Ricoh Co., Ltd., and image production was repeated 10,000 times. As a result, clear images were obtained even after 100,000 repetitions.

From this, it can be understood that the photoreceptor of the present invention is also excellent in durability.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention.

Claims (1)

[Claims] 1.4 In a laminated electrophotographic photoreceptor having a charge generation layer and a charge transport layer on an electrostatic support, the charge generation layer has the general formula (1) (wherein, X is a substituted or unsubstituted aromatic ring). or a heterocycle, and Ar represents a substituted or unsubstituted aromatic ring or a heterocycle.