JPS61132953A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance the sensitivity to a semiconductor laser beams, and aptitudes to repeated uses and production operability, etc., by incorporating a specified trisazo pigment in an electrostatic charge generating layer and a triphenylamine compd. in a charge transfer layer. CONSTITUTION:The intended electrophotographic sensitive body is obtained by laminating on a conductive substrate the charge generating layer, contg. as a charge generating material the trisazo pigment represented by formula I in which R being one of formulae II, III, IV, etc., and on this layer the charge transfer layer contg. as a charge transfer material the triphenylamine compd. represented by formula V in which each of R1, R2, R3 is H, lower alkyl, lower alkoxy, phenyl, phenoxy, or Cl. Both compds. of formula I, V are the known compds., and the former can be prepared easily by the method described in Japanese Open Patent S-57-195767, and the latter by the method described in JACS Vol. 90, P. 3925 (1968), etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a photoreceptor for electrophotography, and more particularly, a layer containing a substance that generates charge carriers (hereinafter referred to as a charge carrier) when irradiated with light (hereinafter referred to as a charge carrier). , charge generation layer) and a layer containing a substance (hereinafter referred to as charge transporting material) that receives and transports charge carriers generated by the charge generation layer (hereinafter referred to as charge transporting layer) or affI. This invention relates to a type of electrophotographic photoreceptor.

Prior Art Conventionally, there have been inorganic photoreceptors for electrophotography, such as those using ceres/and their alloys, or photoreceptors in which dye-cooling zinc oxide is dispersed in a binder resin.
In addition, organic substances include 2,4.7-dolinitro9
-Fluorenone (hereinafter referred to as TNF) and poly-N-
A typical example 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 photoreceptors have difficult manufacturing conditions.

It is difficult to process into a belt shape due to high manufacturing costs and lack of flexibility, and must be handled with care as it is sensitive to heat and mechanical shock. In addition, zinc oxide photoreceptors are low in cost because they can be manufactured by applying inexpensive zinc oxide to a support, but they generally have low sensitivity and poor surface smoothness, hardness, tensile strength, and abrasion resistance. There are mechanical drawbacks, and there are many problems with durability as a photoreceptor for plain paper copying machines that are normally used repeatedly. 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 these, conventional organic photoreceptors are laminated base photoreceptors in which a thin film of organic pigment is formed on a conductive support (charge generation layer), and a layer mainly composed of a charge transport substance (charge transport layer) is formed on top of this. It is attracting attention as a photoreceptor for plain paper copying machines because it generally has higher sensitivity and stable chargeability than photoreceptors, and some are used for photoreceptors.

The conventional laminated photoreceptor made by Hashi is one in which (1) a perylene derivative is used in the charge generation layer and an oxadiazole derivative is used in the charge transport layer (see U.S. Pat. No. 3,871,882) (2) As the charge generation layer , using an organic amine as a bath medium, coated with Chlordia/Blue, and using a pyrazoline derivative as a charge transport layer (see JP-A-52-55643 and JP-A-52-72231) (3) As a charge generation layer, a triphenylamine trisazo pigment (Japanese Patent Application Laid-Open No. 53-132347
A dispersion of 2,5-bis(4-diethylaminophenyl)-1,3 is applied to the charge transport layer by coating a dispersion of 2,5-bis(4-diethylaminophenyl)-1,3 in a dispersion medium such as tetrahydro-7rane.
, 4-oxadiazole, or those using TNF't- are well known.

However, it is true that even though the conventional type photoreceptor has many advantages, it also has various disadvantages.

For example, although the photoreceptor using the perylene hinderer 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. Furthermore, since the perylene derivative, which is the charge-generating substance that controls the spectral sensitivity of this photoreceptor, does not absorb in the entire visible range, it has drawbacks such as being unsuitable as a photoreceptor for color copying machines. .

In addition, Chlordiane blue and Virazo vy shown in (2)
Although the photoreceptor using a VI conductor has relatively good sensitivity in experiments conducted by the present inventors, it is necessary to use an organic amine (e.g., ethylenediamine), which is generally difficult to handle, as a coating solvent to form a charge generation layer. Yes, there are many drawbacks in making photoreceptors.

Furthermore, the photoreceptors shown in (3)K were devised by the present inventors, and these photoreceptors are made by using a dispersion liquid (a dispersion liquid in which fine pigment particles are dispersed in an organic solvent) as a method for forming charge-generating NIT. Although it has the advantage of being easily formed by spreading a binder resin onto a support, to which a binder resin may be added if necessary, the sensitivity is somewhat low, making it unsatisfactory as a photoreceptor for high-speed copying machines.

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 wavelength range of semiconductor lasers is particularly desired. The reality is that the sensitivity is so low that it cannot be put to practical use.

The mechanism of electrostatic latent image formation in this type of layered photoreceptor is that when the photoreceptor is charged and then irradiated with light, the light passes through the transparent carrier N, and the charge-generating material in the charge-generating layer The charge generating substance that has absorbed the light generates charge carriers, which 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 a silent TK image is formed by neutralizing the charges on the surface of the photoreceptor. Therefore, the charge-generating substance used in this type of photoreceptor is required to efficiently generate charge carriers when irradiated with light for forming an image.

On the other hand, the charge transport material is required to be transparent to the light used, capable of maintaining a desired charging potential, and to have the ability to promptly transport the charge carriers generated by the charge generation material when irradiated with light. Ru.

Purpose In view of the above points, the present inventors have aimed to develop an fkMl photoreceptor that is highly sensitive, 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 intensive research on many charge-generating substances and charge-transporting materials, we found that even in the trisazo pigment represented by the general formula (1) below, there are differences in the types and positions of substituents as charge-generating substances. Characteristics are thick (different,
We have discovered that trisazo pigments in which R is as shown below have particularly excellent properties, and that their photoreceptor properties vary greatly depending on the combination of charge-generating substances and charge-transporting substances. Through a specific combination of the following, a photoreceptor with excellent photosensitive properties was obtained and the above objectives were achieved.

An object of the present invention is to laminate a charge-generating layer containing a charge-generating substance with extremely excellent charge carrier-generating ability and a charge-transporting layer containing a charge-transporting substance that exhibits excellent performance when used together with the charge-generating substance. By providing a sufficient Vtt level in a dark place and quickly dissipating the surface charge during exposure, it is possible to eliminate banding, exposure, development, transfer, and cleaning in the repeating process of one copy. The object of the present invention is to provide a laminated electrophotographic photoreceptor whose characteristics do not change at all even after repeated steps.

Structure 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 IR and charge generation layer have the general formula (1) (% formula %). containing a trisazo pigment as shown and having a charge carrier (wherein
``l s R1* R1 may be the same or different (
, hydrogen, lower alkyl group, lower alkoxy group, phenyl group, phenoxy group, or chlorine atom).

Here, specific examples of the lower alkyl group in R1y g and R8 of general formula (2) include a methyl group, an ethyl group,
Examples include propyl group and butyl group.

Further, specific examples of the lower alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and the like.

The triphenylamine compound represented by the general formula (2) as described above is a known compound, and 1, for example, R, F,
Nel+on and R,N, Adams, J.
, Am, Chsm.

Soc, 90.3925 (1968).

On the other hand, the trisazo pigment represented by the general formula 11) used in the charge generation layer of the present invention is a known substance, and is produced, for example, by the method described in JP-A No. 57-195767.

Next, specific examples of the trisazo pigment represented by the general formula (1) and the styryl compound represented by the general formula (2) obtained as described above are shown in Tables 1 and 2, respectively.

Table-1 I -2 Next, the present invention will be explained in more detail with reference to the drawings.

The attached drawing is an enlarged sectional view of an electrophotographic photoreceptor showing an embodiment of the present invention. This photoreceptor is a photoreceptor/6 consisting of a charge generating JT+722 and a charge transport layer 33 on a conductive support 11.
44.

Here, the conductive support is a metal plate, metal drum, or metal foil made of aluminum, nickel, chromium, etc.;
A plastic film provided with a thin layer of aluminum, tin oxide, indium oxide, chromium, palladium, etc.; paper or plastic film coated with or impregnated with a conductive substance, etc. are used.

The charge generation layer is a liquid in which a specific trisazo pigment represented by the general formula (1) is made into fine particles by means such as a ball mill and dispersed in a suitable solvent.

Or, if necessary, it can be formed by coating a dispersion in which a binder resin is dissolved onto a conductive support.

The charge generation layer formed in this way is further coated with
For example, surface finishing is done by methods such as puff polishing,
Adjust the film thickness. The binder resin used here is polyester [fat, ;'? Examples include Ral resin, ethyl cellulose, epoxy resin, phenoxy resin, acrylic resin, vinylidene chloride resin, polystere/1fI4 resin, polybutadiene resin, and copolymers thereof. These may be used alone or in a mixed state of 2$1 or more.

The thickness of the charge generation layer is 0.01 to 5 μm, preferably 0.01 to 5 μm.
05-2 μm and the proportion of trisazo pigment in this layer is 10-100% by weight, preferably 30-95% by weight. If the thickness of the charge generation layer is less than 0.01 .mu.m, the sensitivity will be poor; if it is more than 5 .mu.m, the potential will be poorly maintained. If the proportion of the trisazo pigment in the charge generation layer is less than 10% by weight, the sensitivity will be poor.

The charge transport layer is formed by dissolving a triphenylamine compound represented by the above-mentioned general formula (2) and a binder resin in a suitable solvent such as tetrahydrofuran and spreading it on the charge generation layer. . Examples of binder resins used here include polycarbonate resins, polyester resins, polystyrene/resins, polyurethane resins, epoxy resins, phenoxy resins, acrylic resins, silicone resins, and copolymers thereof. These 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. Additives used for this purpose include halogenated/
Laugh-in, Sial? /I/7 tallate, silicone oil, etc.

The ratio of the triphenylamine compound contained in the charge transport layer is 10 to 80 times Ik, preferably 25 to 751 times
The film thickness is 2 to 100 μm, preferably 5 μm.
~40 μm. If the proportion of the triphenylamine compound in the charge transport layer is less than 10% by weight, the sensitivity will be poor; if it is more than 80% by weight, the layer will become brittle, or the layer will become cloudy due to precipitation of crystals, which is undesirable. The thickness of
If the diameter is less than 40 μm, the potential will not be maintained properly, and if the diameter is greater than 40 μm, the residual potential will be high.

In addition, in the photoreceptor of the present invention, a barrier layer may be provided between the conductive layer and the charge generation layer, an intermediate layer between the charge generation layer and the charge transport layer, and an overcoat layer on the charge transport layer, if necessary. can.

Effects Due to the structure described above, the laminated electrophotographic photoreceptor of the present invention is easier to manufacture than the conventional laminated electrophotographic photoreceptor and can be used repeatedly, as is clear from the Examples and Comparative Examples described later. It has excellent properties such as stable characteristics and high sensitivity even in the semiconductor laser wavelength range (approximately 800 nm).

Example 1 Trisazo pigment l' represented by formula (1-1) in Table-1
Add 6 parts by weight of the 5-fold Ik% tetrahydrofuran 7 solution of iL Okibe, Tetrahydrofuran 19] [Okibe, Holivinylzotyral <tjN (XYHL; manufactured by Unio/No. Carnonoid Qf2 Stick Kanno Nanani) in a mail mill. It was crushed. Next, this pulverized mixture was taken out, and while stirring, it was diluted by adding Tetrahydro 7 Run 104 times itm. This liquid was applied on a polyester film coated with aluminum film with a wet gap of 35 μm using a doctor grade filter. Apply and dry at 80'Q for 5 minutes, 1.0
A charge generation layer having a thickness of μm was formed. In the charge generation layer,
10 parts of a triphenylamine compound represented by the structural formula (2-7), a polycarbonate resin (-
1300; manufactured by Teijin Kasei Co., Ltd.) 101i parts, Silico 7 oil # (KF-50; manufactured by Shin-Etsu Chemical Co., Ltd.) α0
A solution containing 2 parts by weight of 0.02 parts by weight and 80 parts by weight of tetrahydrofuran was spread using a doctor blade with a wet gap of 200 μm, and dried at 80° C. for 2 minutes, then at 100° C. for 5 minutes to form a 23 μm thick O11VT transport layer. , photoreceptor A
1 was made.

Examples 2 to 10 The following photoreceptors were produced in exactly the same manner as in Example 1, except that the trisazo pigment and triseptadylamine compound shown in the table below were used.

Example 11%15 Same as Example 1, except that the polyvinyl buderal resin in Example 1 was replaced with a polyester resin (Vylon 200; manufactured by Toyobo Co., Ltd.) and the trisazoceritinaceae and triphenylamine compounds shown in the table below were used. The following photoreceptors were prepared in exactly the same manner.

Table 4 Comparative Example 1 N,N'-dimedelperiley-3,
4,9,10-tetracarzinoacid diimide was vacuum-deposited on an aluminum plate at a vacuum degree of 10 cm, a deposition source temperature of 350° C., and a deposition time of 3 minutes to form a charge generation layer. Next, 5 parts by weight of 2,5-bis(4-dietheraminophenyl A/)-1,3,4-oxadiazole and a polyester resin (manufactured by DuPont, Polyester Adhesive 49000) were then applied on the charge generation layer. A solution consisting of 5 parts by weight and 90 parts by weight of tetrahydrofuran was applied, and 12 parts by weight were applied.
A charge transport layer having a thickness of about 10 μm was formed by drying at 0° C. for 10 minutes, and a comparative photoreceptor was prepared.

Comparative Example 2 As a charge-generating substance, 1.08 parts by weight of Chlordiane Blue, which is a PE/Gidi Y-based pigment, was added to ethylenediamine 2 Table 46
A charge generation layer coating solution was prepared by dissolving 0,000 g of n-butylamine in 3 parts by weight and adding 5,436 parts by weight of tetrahydro 7 run to this solution without stirring. Next, this coating solution was applied onto a polyester film on which aluminum was vapor-deposited using a doctor blade, and dried at 80° C. for 5 minutes to form a charge generation layer having a thickness of about 0.5 μm. 1 part by weight of 1-722-3-(4-diethylaminophenyl)-5(4-diethylaminophenyl)-pyrazoline and a polycarbonate resin () are placed on the charge generation layer.
A solution consisting of 1 part by weight of K-1300 (manufactured by Teijin Kasei Ltd.) and 8 parts by weight of tetrahydrofuran was applied with a doctor blade, heated at 80°C for 2 minutes, and then heated for 10 minutes.
A charge transport layer having a thickness of about 20 μm was formed by drying at 0° C. for 5 minutes, and a comparative photoreceptor black 2 was prepared.

Comparative Example 3 Triphenylamine pigment used as charge generating substance 4
, 4', 4'-tris[2-hydroxy-3-
2 parts by weight of (2-methoxyphenylcarbamoyl)-1-naphthylazo]triphenylamide and 98 parts by weight of tetrahydrofuran are pulverized and mixed in a 2-lumil, and the resulting dispersion is applied onto an aluminum-deposited polyester film using a doctor blade. This was then air-dried to form a charge generation layer with a thickness of 1 μm. On the other hand, 2 parts by weight of 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, 2 parts by weight of polycarbonate resin (Panlite L; manufactured by Teijin Kasei Ltd.), and 4 parts by weight of tetrahydrofuran.
6NIk part was mixed to form a solution, which was applied onto the charge generation layer using a doctor blade, and dried at 120°C for 10 minutes to form a charge transport layer having a thickness of 10 μm. Created.

Comparative Example 4 11 parts by weight of polyester resin (manufactured by DuPont, Polyester Adhesive 49000), triphenylamine pigment 4,4',4'-)ilith[2-hydroxy-3-(z,5- 1 part by weight of (dimethoxyphenylcarbamoyl)-1-su7terazo]triphenylamine y and 26 parts by weight of tetrahydrofuran were ground and mixed in a mail mill, and the resulting dispersion was applied onto an aluminum-deposited polyester film using a doctor blade. Comparative photosensitive layer 4 was obtained by drying at 100° C. for 10 minutes to form a photosensitive layer with a thickness of 7 μm.

Comparative Example 5 10 parts by weight of polyester resin, 10 parts by weight of 2,4.7-trinitro-9-fluorenone, 1 part by weight of the general formula (1
), 2 parts by weight of a trisazo compound in which R is a 2-methyl-4-methoxyphenyl group (a trisazo compound disclosed in JP-A-53-132347) and 7 parts/198 g of tetrahydro were ground in a mail mill. The dispersion obtained was mixed and applied onto a polyester film coated with aluminum using a doctor blade.
A comparative photoreceptor &5 having a photosensitive layer having a thickness of 10 μm was prepared by drying at 0° C. for 10 minutes.

The photoreceptor A1-Black 15 and the comparative photoreceptor A1-Ya 5 prepared in step 5 above were tested using an electrostatic copying paper tester (■
Kawaguchi Electric Seisakusho, Model 5P428) was used to emit a - (or +) 6Kv corona for ttzo seconds to generate a negative or positive charge, and then leave it in a dark place for 20 seconds.
The surface potential Vpo (malt) at that time was measured, and then the surface was illuminated with an illuminance of 4.51 by a tungsten lamp.
Light is irradiated so that the surface potential becomes Vpo.
Find the time (seconds) until it reaches % of the exposure amount gg (lu
x・5ec) was calculated.

In addition, the following measurements were performed to examine the sensitivity of each photoreceptor to long wavelength light.

The photoreceptor was charged by corona discharge in a dark place without bathing, and then monochromatic light of 1 μw/d separated at 800 nm was irradiated onto the photoreceptor using a monochromator. Next, the time (sec) for the surface potential to decay to the moon was determined (at this time, the attenuation of the surface potential due to dark decay was corrected), and the amount of exposure (μwesec/m2) was determined, and the light decay rate (matrix) was determined. olt
*cj・μ−@i′) was calculated. Table these results.
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 photoreceptors &1 to black 5, and has a higher sensitivity in the semiconductor laser wavelength range (800 nm). ), it can be seen that the sensitivity is extremely excellent. Also,
In its production, it is not necessary to use the organic amine used in producing comparative photoreceptor 2, which is advantageous in terms of production. Further, each of the photoreceptors 1 to 15 of the present invention was installed in an electrophotographic copying machine (M-10 manufactured by Ricoh Co., Ltd.), and image production was repeated 10,000 times. the result,
Clear images were obtained from all photoreceptors.

[Brief explanation of drawings]

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 3
3...Charge transport layer 44...Sensitive optical layer Procedural amendment January 24, 1985 Manabu Shiga, Commissioner of the Patent Office 1, Indication of the case 3, Person making the amendment Relationship with the case Patent applicant Tokyo Rico Co., Ltd., 1-3-6 Nakamagome, Ota-ku, Tokyo (674) - Representative Hama 1) Hiroshi 4, Agent 5, "Detailed description of the invention" column 6 of the specification subject to amendment, 1982 Patent Application No. 254727 2, Name of the invention Electrophotographic photoreceptor 3, Person making the amendment Relationship to the case Patent applicant 1-3-6 Nakamagome, Ota-ku, Tokyo (674) ) Ricoh Co., Ltd. Representative Hama 1) Hiro 4, Agent 5, Date of amendment order (IJ Meisho f No. 11 Shell No. q 1 person Ding Suru 1 Jisesuru 1) 6, Specification subject to amendment “ Column 7 of “Detailed Description of the Invention”, Contents of Amendment (1) rR,F. Nelson and R,N, Adams, J, page 11, lines 15-16 of the specification.
, Am. Chew, Sac, y J.
F., Nelson and R.N. Adams, J., Am., Chem., Sac.
, )j and correct it. that's all.

Claims (1)

[Claims] 1. In a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are provided on a conductive support, the charge generation layer has the general formula (1) ▲ Numerical formula, chemical formula, table, etc. ▼(1) (However, R represents ▲There are mathematical formulas, chemical formulas, tables, etc.▼) Contains the trisazo pigment shown by the formula (2), and the charge transport layer has the general formula (2) ▲There are mathematical formulas, chemical formulas, tables, etc. ▼(2) (In the formula, R_1, R_2, and R_3 may be the same or different and represent hydrogen, a lower alkyl group, a lower alkoxy group, a phenyl group, a phenoxy group, or a chlorine atom) An electrophotographic photoreceptor characterized by containing a compound.