JPS58122548A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic receptor having high sensitivity to a region including a semiconductor laser wavelength region, adaptability to high speed copying, and long service life, by adding a specified trisazo pigment to a charge generating layer and a specified anthracene compd. to a charge transfer layer. CONSTITUTION:A 0.01-5mum thick charge generating layer formed on a conductive substrate contains 10-100wt% trisazo pigment having formulaIin which R is one of formula III, IV, and V. On this layer, a 2-100mum thick charge transfer layer is laminated contg. an anthracene compd. having formula II in which R1 is H or halogen; R2 is H, 1-4C alkyl, such alkoxy, dialkylamino, diaralkylamino optionally substd. CH3, Cl, or the like; and R3 is H, alkyl, or halogen. The obtained laminate type photoreceptor consisting of the substrate, the charge generating layer, and the charge transfer layer has high sensitivity to a wide region especially including 800nm wavelength laser beams, and long service life.

Description

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

) and a layer ' (hereinafter referred to as charge transport layer) containing an initial layer (hereinafter referred to as charge transport material) that receives and transports generated charge carriers (hereinafter referred to as charge transport layer). Regarding photoreceptors 0 Conventionally, as photoreceptors for electrophotography, there have been inorganic ones using selenium and its alloys, or photoreceptors dispersed in a binder resin such as dye-sensitized zinc oxide.
In addition, for organic substances, 2, 4. ? -) Dinitro-9
-Fluoreno/(hereinafter referred to as TNF) and poly-N-
A typical example is one using a charge transfer complex with vinyl carnobu-/I/ (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. Therefore, care must be taken when handling. In addition, zinc oxide photoreceptors can be manufactured using inexpensive zinc oxide by coating it on a support, so the cost is low;
Generally, it has low sensitivity, mechanical defects such as surface smoothness, hardness, tensile strength, and abrasion resistance, and there are problems with durability as a photoreceptor for plain paper copiers that are usually used repeatedly. Furthermore, a photoreceptor using a charge transfer complex of TNF and PVK has low sensitivity, making it unsuitable as a photoreceptor for high-speed copying machines.

In recent years, extensive research has been carried out to eliminate these drawbacks of photoreceptors, and various organic photoreceptors have been proposed.Among them, a thin film of organic pigment is formed on a conductive support to generate charge. Laminated photoreceptors with a charge transporting material layer (charge transporting layer) formed thereon generally have higher sensitivity and stable chargeability compared to conventional organic photoreceptors. For these reasons, it has attracted attention as a photoreceptor for plain paper IIv machines, and some of them are in practical use.

Conventional laminated photoreceptors of this type include (1) one in which a perylene derivative is used in the charge generation layer and an oxadiazole derivative is used in the charge transport layer (see US Pat. No. 3,871,882); As a charge generation layer, a layer coated with resin psidia/blue was used using an organic amine as a solvent, and a pyrazoline derivative was used as a charge transport layer. Showa 52-7
2231), (3) As a charge generation layer, a triphenylamine trisazo pigment (JP-A-53-13
2,5-bis(4-diethylaminophenyl) as a charge transport layer.
-t, S.

Those using 4-oxadiazole or TNF are known.

However, although conventional photoreceptors of this type have many advantages, they also have various disadvantages.

For example, although the photoreceptor using the perylene derivative and oxadiazole derivative shown in (1) above may have no practical problems, it has low sensitivity for use in higher-speed copying machines and the like. Additionally, perylene derivatives, which are the charge-generating substances that control the spectral sensitivity of this photoreceptor, have the disadvantage of not being absorbent over the entire visible range, making them unsuitable as photoreceptors for color copying machines. There is.

Furthermore, although the photoreceptor using chlordiane blue and pyrazoline derivatives shown in (2) has relatively good sensitivity in our experiments, it is generally not used as a coating solvent for forming a charge generation layer. It is necessary to use a difficult organic amine (e.g. ethylenediamine), which has many disadvantages in producing a photoreceptor.Also, the photoreceptor shown in (3) was proposed by the present inventors, and these photoreceptors do not have a charge generation layer. The formation method is to apply a pigment dispersion in which fine pigment particles are dispersed in an organic solvent (a binder resin may be added if necessary) onto a support, which has the advantage of being easy to form, but has a slight sensitivity problem. Because of the low .

On the other hand, the demand for photoreceptors for laser printers has increased in recent years, and the development of highly sensitive photoreceptors in the O wavelength range of semiconductor lasers is desired, but the photoreceptors mentioned above are extremely sensitive to these semiconductor lasers. The reality is that it is so low that it cannot be put to practical use.

The mechanism of electrostatic latent image formation in this type of laminated photoreceptor is that when the photoreceptor is charged and then irradiated with light, the light passes through a transparent charge transport layer and is absorbed by the charge generation substance in the charge generation layer. , the charge-generating substance that has absorbed the light generates charge carriers, and the charge carriers are injected into the charge transport layer and move in the charge transport layer according to the electric field generated by the charging,
It is believed that an electrostatic latent image is formed by neutralizing the charges on the surface of the photoreceptor. Therefore, charge-generating materials used in this type of photoreceptor are required to efficiently generate charge carriers when irradiated with light for image formation.On the other hand, charge-transporting materials are required to efficiently generate charge carriers when irradiated with light for image formation. The material is required to be transparent and capable of maintaining a desired charging potential, and to have the ability to promptly transport the charge carriers generated by the charge-generating substance when irradiated with light.

In view of the above points, the present inventors aimed to develop a laminated photoreceptor that has a high e-degree, exhibits almost flat sensitivity over the entire visible range and the wavelength range of semiconductor lasers, and is easy to manufacture. As a result of extensive research on a large number of charge-generating substances and charge-transporting substances, we have found that even in the trisazo pigment represented by the following general formula (1), the characteristics of the charge-generating substance vary greatly depending on the type and position of the substituent R. It has been found that trisazo pigments in which R is as shown below have particularly excellent properties, and that their photoreceptor properties are greatly improved by the combination of a charge generating substance and a charge transporting substance. By means of a specific combination thereof, a photoreceptor with excellent photosensitive properties was obtained and the above objectives were achieved.

The object of the present invention is to provide a charge generation layer containing a charge generation substance with extremely excellent charge carrier generation ability and a charge transport layer containing a charge transport substance that exhibits excellent performance when used together with the charge generation layer. This provides a sufficient charging potential in the dark and quickly dissipates the surface charge when exposed to 11 g of light. An object of the present invention is to provide a laminated electrophotographic photoreceptor whose characteristics do not change in any way even after repeated use. , the charge generation layer contains a trisazo pigment represented by the general formula (1), and the charge transport layer has the general formula (2) [wherein R1 represents hydrogen or a halogen atom, and R8 represents hydrogen and a carbon number of 1 to 4] represents an alkyl group, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group, or a substituted or unsubstituted dialkylamino group, and R1 represents hydrogen, an alkyl group, or a halogen atom. An electrophotographic photoreceptor characterized by comprising:

The trisazo pigment represented by the general formula (1) used in the present invention is shown in Table 1, and the anthracene compound represented by the general formula (2) is exemplified in Table 2.

Table 1 Table 2 Next, the present invention will be explained in more detail. Figure 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.

The conductive support used in the present invention includes a metal plate, metal drum, or metal foil made of aluminum, nickel, chromium, etc., and a thin layer of aluminum, tin oxide, indium oxide, chromium, radium, etc. A plastic film and a paper or plastic film coated with or impregnated with a conductive substance are used.The charge generation layer is made of a specific trisazo pigment represented by the general formula (1) shown above using a method such as i-lumil. as particles,
It is formed by coating a conductive support with a dispersion in which it is dispersed in a suitable solvent, or if necessary, a binder resin is dissolved therein.If necessary, the surface is finished by a method such as knot polishing. The film thickness has been adjusted.

The thickness of this charge generation layer is 0.01-8 μm, preferably 0.05-2 μm, and the proportion of the trisazo pigment in the charge generation layer is 10-100% by weight, preferably 30-95%.
If the film thickness of the charge generation layer (weight -) is less than 0.01 μm, II8& is poor, and if it is greater than 6 μm, potential retention is poor.

Furthermore, if the proportion of the trisazo pigment in the charge generation layer is less than 10% by weight, the sensitivity is poor.

The charge transport layer is formed by applying a solution of the anthracene compound represented by the general formula (2) and a binder resin dissolved in a suitable solvent such as tetrahydrofuran onto the charge generation layer. Here, the proportion of the anthracene compound contained in the charge transport layer is 10 to 80% by weight, preferably 25 to 75% by weight, and the film thickness is 2 to 100 μm, preferably 5 to 40 μm. The proportion of anthracene compound contained in the charge transport layer is 10
If it is less than 800 parts by weight, the sensitivity will be poor, and if it is more than 800 parts by weight, the film will become brittle or crystals will precipitate and the charge transport layer will become cloudy, which is not preferable. Further, if the thickness of the charge transport layer is 5 μm or less, the potential is not maintained well, and if the thickness is 40 μm or more, the residual potential becomes high.

The binder resin for the charge generation layer used here is:
Polyester resins, zotyral resins, ethyl cellulose resins, epoxy resins, acrylic resins, vinylidene chloride resins, polystyrene/resins, polybutadiene resins, and copolymers thereof, etc., are used singly or in a mixed state of two or more. It will be done.

Examples of binder resins for the charge transport layer include I-licarbonate resins, polyester resins, polystyrene resins, polyurethane resins, I-oxy resins, acrylic resins, silicone resins, and copolymers thereof. is 1
Various additives can be added to the charge transport layer for the purpose of improving flexibility or durability. Additives used for this purpose include halogenated and
Typhi/1 dialkyl phthalate, silicone oil cape is applied.

In addition, in the photoreceptor of the present invention, if necessary, a nonaryl layer is provided between the conductive layer and the charge generation layer, an intermediate layer is provided between the charge generation layer and the charge transport layer, and an O/O layer is provided on the charge transport layer. - A coating layer can also be provided.

The structure of the present invention is as described above, and as is clear from the Examples and Comparative Examples described later, the present invention is easier to manufacture than an electrophotographic photoreceptor having a conventional laminated photosensitive layer. It is an electrophotographic photoreceptor that has excellent properties such as stable characteristics even after repeated use of the photoreceptor and high sensitivity even in the wavelength range of semiconductor lasers (about soon nm).

Next, the present invention will be explained in detail with reference to Examples, but the embodiments of the present invention are not limited thereto.Example 1 Trisazo pigment represented by formula (1-1) in Table-1 1 part by weight of tetrahydrofuran, 19 parts by weight of tetrahydrofuran, and 6 parts by weight of a 5-weight solution of polyvinyl butyral resin (XYHL; manufactured by Union Calf Zeta Plastic Kanno Denie) in a 5-weight cup of tetrahydrofuran were sufficiently pulverized in a Zeel mill. F
! KK This pulverized mixture was taken out, and while stirring slowly, 104 parts by weight of tetrahydrone was added to dilute it.
This liquid was applied onto a polyester film on which aluminum had been vapor-deposited using a doctor blade with a wet gap of 35 μm, and dried for 5 minutes at SOC to form a charge generation layer with a thickness of O.S μm. 10 parts by weight of an anthracene compound represented by formula (2-1) and I liquor were added to the charge generation layer.
10 parts by weight of nate resin (Nose/Light 113'OO: manufactured by Teijin Kasei Ltd.), silicone oil (KF-50:
A solution containing 80 parts by weight of tetrahydrofuran (manufactured by Shin-Etsu Chemical Co., Ltd.) o, oo in a wet gap 200
Apply with μ lightning using a doctor blade and heat at 80C for 2 minutes.
Next, it was dried at 1,000° C. for 5 minutes to form a charge transport layer with a thickness of 22 μm, thereby producing a photoreceptor AI.

Examples 2 to 9 The following photoreceptors were prepared in exactly the same manner as in Example 1 except that the trisazo pigment and anthracene compound shown in the table below were used. Change the polyvinyl butyral resin in 1 to 4-lyester resin (・Daniiro 7200; manufactured by Toyoboron Co., Ltd.),
Example 1 except that the trisazo pigment shown in the table below was used.
The following photoreceptor was prepared in exactly the same manner as above.

(Left below) Comparative example! N,N'-dimethylperylene- as a charge generating substance
3,4,9,10-tetracarminic acid diimide was deposited on an aluminum plate under vacuum [10'-Hgs vapor deposition source temperature 350
A charge generation layer was formed by vacuum evaporation under conditions where the cs deposition time was 3 minutes. Next, on this charge generation layer, 5 parts by weight of 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole and 5 parts by weight of a polyester resin (Polyester Adhesive 4900G manufactured by Tune Co., Ltd.) were applied. and 90 parts by weight of tetrahydroflough,
It was dried at 120C for 10 minutes to form a charge transport layer with a thickness of about 10 μm, thereby producing comparative photoreceptor A1. Comparative Example 2 1.08 parts by weight of Chlordiane Blue, a benzidine pigment, was used as a charge generating substance. Ethylenediamine 24.4
6 parts by weight, 111 parts of 20.0 s of n-butylamine was added to this solution without stirring, and 54.36 parts by weight of tetrahydrofuran was further added to prepare a charge generation layer coating solution. was applied using a doctor blade onto a polyester film coated with aluminium, and aO
C for 5 minutes to form a charge generation layer with a thickness of about 0.5 μm. On the charge generation layer, 1-F, Enyl-A-(4
-diethylaminosteryl)-5-(4-diethylaminophenyl)-pyrazoline 1 part by weight, polycarmenate resin (Pan 2i) K-1300: manufactured by Teijin Kasei Ltd.)
A solution consisting of 1 part by weight and 8 parts by weight of tetrahydrofuran was applied using a doctor blade and dried at 80C for 2 minutes and then at 100C for 5 minutes to form a charge transport layer with a thickness of about 20 μm. I created A2.

Comparative Example 3 Triphenylamine pigment used as charge generating substance 4
, 4', 4'-) squirrel [2-hydrokai 3-(
2-)) 2 parts by weight of xyphenylcarnogmoyl)-1-naphthylazo]triphenylamine and 98 parts by weight of tetrahydrofuraf were pulverized and mixed in an I-rumyl, and the resulting dispersion was coated on an aluminum-deposited polyester film with KF.
A charge generating layer having a thickness of 1 .mu.m was formed by coating with Kumade 1v-de and air drying. On the other hand, 2. 2 parts by weight of S-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, 2 parts by weight of polycarbonate resin (Pan 2 It L: Teijin Kasei Ltd.), and 1111 parts of tetrahydrophene 46-weight The mixture was mixed to form a solution, which was applied onto the charge generation layer using a doctor blade and dried at 120 rpm for 10 minutes to form a charge transport layer with a thickness of 10 μm, thereby producing a comparative photoreceptor A3.

Comparative Example 4 1 part by weight of polyester resin (manufactured by DuPont, Polyester Adhesive 49000), triphenylamine pigment 4,4'#4'-) 9s[2-hydroxy-3-(2,!l) 1 part by weight of -dimethoxyphenylcarnomoyl)-1-naphthylazo]triphenylamine and 26 parts by weight of tetrahydrofuran were pulverized and mixed in an I-lumil, and the resulting dispersion was spread on an aluminum-deposited polyester film using a doctor blade. The mixture was washed with a mulberry cloth and dried for 10 minutes with toot:' to obtain a comparative photoreceptor A4 having a photosensitive layer with a thickness of 7 μm.

Comparative Example 5 10 parts by weight of polyester resin, 7710 parts by weight of 2,4.7-dolinitro-9-fluorene, general formula (1) of the present invention
2 parts by weight of a trisazo compound in which R is a 2-methyl-4-methoxyphenyl group (trisazo compound disclosed in JP-A-53-132347) and 198 parts by weight of tetrahydrofuran are pulverized and mixed in an I-lumyl,
The obtained dispersion was spread on a polyester film coated with aluminum using a doctor blade, and heated at 100C.
A comparative photoreceptor AI5 having a photosensitive layer having a thickness of 10μ was prepared by drying for 10 minutes.

The photoreceptors A1 to All and comparison photoreceptors A1 to A3 prepared as described above were tested using an electrostatic screen paper tester ((
Newly manufactured by Kawaguchi Electric Co., Ltd., BP42
Or +) 6KV:! After performing Rona discharge for 20 seconds to charge it negatively or positively, it was left in a dark place for 20 seconds, the surface potential Vpo (Mao1t) at that time was measured, and then the surface was illuminated with an illuminance of 201
The surface potential becomes vpo when the light is irradiated at 5 m.
Find the time (seconds) until 03(), and calculate the exposure amount E%(1
scx-sac) was calculated.

In addition, in order to investigate the sensitivity of each photoreceptor to long wavelength light, the following measurements were performed. First, each photoreceptor was charged by microdischarge in a dark place, and then a monochromator was used to charge the photoreceptor at 800 nm. The time required for the surface potential to attenuate to A after irradiation with monochromatic light of lμη spectrally divided into -eaJcd) to calculate the light attenuation rate (malt-d.μ!-1.1 heat). These results are shown in Table-5.

(Leaving space below) Table 5 As is clear from the results in Table 5, the laminated photoreceptor of the present invention has higher sensitivity in the visible range than the comparative photoreceptor Al-Al5K, and in the semiconductor laser wavelength range (800 nm). It can be seen that the photoreceptor A2 has an extremely excellent sensitivity.In addition, it is advantageous in terms of production since it is not necessary to use the organic amine used in the production of the comparison photoreceptor A2. The photoconductor Al~412 of the present invention was used in an electrophotographic copying machine (F-4700 manufactured by Ricoh Co., Ltd.).
) K was attached, and image display was repeated 10,000 times. As a result, clear images were obtained from all photoreceptors.

From this, it can be understood that the photoreceptor of the present invention has extremely excellent durability.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of an electrophotographic photoreceptor showing an embodiment of the present invention. 11... Conductive support 22... Charge generation layer 33
... Charge transport layer 44 ... Photosensitive layer procedural amendment March 3, 1980 Haruki Torita, Commissioner of the Japan Patent Office 1. Indication of the case 1982 Patent Application No. 5187 2. Name of the invention Electrophotographic photosensitive Body 3. Person making the amendment Relationship to the case Patent applicant Rico Co., Ltd. 1-3-6 Nakamagome, Ota-ku, Tokyo (674) - Representative Takeshi Oue 4, Agent 6, Contents of the amendment (1) "r physics" in the third line from specification lI2trueF"

Claims (1)

[Scope of Claims] 1. A laminated electrophotographic photosensitive p in which a charge generation layer and a charge transport layer are provided on a conductive support, the charge generation layer containing a trisazo pigment represented by the general formula (1), In addition, the charge transport layer has the general formula (2) [wherein 8. represents hydrogen or a halogen atom, R1 represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group, or a substituted or unsubstituted dialkylamino group, and R1 represents hydrogen.・Represents an alkyl group or a halogen atom. ]. 7. An electrophotographic photoreceptor comprising a tracene compound.