JPH0299968A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the electrophotographic sensitive body having sufficient sensitivity and good durability by incorporating a specific hydrazone compd. into the photosensitive layer on a conductive base. CONSTITUTION:The hydrazone compd. expressed by formula I is incorporated into the photosensitive layer on the conductive base. In formula, I, X is an oxygen atom or sulfur atom; R1, R2 are an alkyl group, aralkyl group or aryl group which may be substd.; (l), (m), (n) are 0 or 1 integer; at least one of (l), (m), (n) is 1; (m) and (n) are not simultaneously 1. The electrophotographic sensitive body with which the high sensitivity and the stable performance in the repetitive use are obtainable is obtd. in this way as well as excellent durability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoreceptor for electrophotography. More specifically, the present invention relates to an electrophotographic photoreceptor characterized in that the photosensitive layer of the conductive support contains a novel disazo compound as a charge generating substance and a novel hydrazone compound as a charge transporting substance.

[Prior Art] Conventionally, inorganic photosensitive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used as photosensitive materials for electrophotographic photoreceptors. However, photoreceptors using these photosensitive materials do not fully satisfy the performance requirements for electrophotographic photoreceptors, such as sensitivity, photostability, moisture resistance, and durability. For example, a photoreceptor using a selenium-based material has excellent sensitivity, but the characteristics of the photoreceptor tend to deteriorate due to crystallization due to heat or adhesion of dirt. Furthermore, since it is manufactured by vacuum evaporation, it is expensive, and it also has many drawbacks, such as being difficult to process into a heald shape because it is not flexible. Photoreceptors using cadmium sulfide-based materials have problems with moisture resistance and durability, and photoreceptors using zinc oxide have problems with durability.

In order to overcome the drawbacks of photoreceptors using these inorganic photosensitive materials, various studies have been made on photoreceptors using organic photosensitive materials.

In recent years, among photoreceptors developed to improve the above-mentioned drawbacks, a functionally separated photoreceptor in which charge generation function and charge transport function are shared by separate substances has been attracting attention. In this functionally separated type photoreceptor, materials having respective functions can be selected from a wide range of materials and combined, so that it is possible to produce a highly sensitive and highly durable photoreceptor.

Electrophotographic properties required for charge transport materials include (I)
The ability of the receiver to accept the charge generated by the charge-generating material is sufficiently high; (2) the receiver must transport the introduced charge quickly; and (3) the charge must be sufficiently transported even in low electric fields and the charge may remain. There are things like not being able to do it.

Furthermore, as a photoreceptor, it must be stable against light and heat received during the repeated charging, exposure, development, and transfer processes during duplication, and must have durability to produce reproduced images that are faithful to the original. .

Various compounds have been proposed as charge transport materials. For example, poly-N-vinylcarbazole has long been known as a photoconductive material, and a product using dirt as a charge transport material has been put into practical use, but it itself lacks flexibility, is brittle, and is prone to cracking. Since it easily occurs, it has poor durability against repeated use. Furthermore, when it is used in combination with a binder to improve flexibility, it has the disadvantage of poor electrophotographic properties.

On the other hand, since low molecular weight compounds generally do not have film properties, they are usually mixed with a binder in any desired composition to form a photosensitive layer. Many charge transport materials have been proposed as low molecular weight compounds. For example, hydrazone compounds have high sensitivity as charge transport substances, and
No. 1, JP-A-55-520G4, JP-A-57-581
No. 56, JP-A No. 57-58157, etc. However, there are problems with decomposition due to ozone generated during corona charging, and stability against light and heat.Although the initial performance is excellent, repeated use causes a decrease in charge retention ability or accumulation of residual potential. The image resulted in a decrease in contrast or a large amount of fog. Although many other charge transport materials have been proposed, the current situation is that none of them practically satisfies the required performance as an electrophotographic photoreceptor, and the development of an even better photoreceptor has been desired.

[Problems to be Solved by the Invention] An object of the present invention is to provide a photoreceptor for electrophotography that has sufficient sensitivity and good durability, and also:
The object of the present invention is to provide a novel charge transport material for use in this purpose.

[Means to solve the problem]

The present inventors have made extensive studies to solve the above problems, and
As a result, -ritual (I) (wherein, It is an aryl group that may be an aryl group.l, m, and n represent an integer of 0 or l.However, at least one of !, m, and n is 1, and m and n are not 1 at the same time.) The present inventors have discovered that a novel hydrazone compound can provide an electrophotographic photoreceptor having excellent properties such as high sensitivity and high durability, and have arrived at the present invention.

That is, the present invention provides a photosensitive layer on a conductive support having a general formula (wherein, X is an oxygen atom or a sulfur atom, R and R2 are optionally substituted alkyl groups, - or aryl group, which is an aryl group that may be at least one substituted. P, m, n
represents an integer of O or 1. However, at least one of P, m, and n is 1, and m and n are the same, with no profanity. ) This is an electrophotographic photoreceptor characterized by containing a hydradun compound represented by:

In R3 and R2 in the above-mentioned formula (I), examples of the alkyl group include a methyl group, an ethyl group, a linear or branched propyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Examples of the aralkyl group include a hensyl group, a phenethyl group, a cinnamyl group, and a naphthylmethyl group.

In addition, as aryl groups, phenyl groups, naphthyl groups,
Examples include anthryl group, and the aryl group I! ! !
! As a group, an alkyl group such as a methyl group or an ethyl group,
Examples include alkoxy groups such as methoxy and ethoxy groups, halogen atoms such as chlorine and bromine, and dialkylamino groups such as dimethylamino and dimethylamino groups.

More specific compounds that can be used in the present invention are shown in Table 1, but the compounds that can be used in the present invention are not limited thereto.

(Left below) ? The hydrazone compound represented by -Funenin (I) above can be synthesized, for example, as follows. -e Formula (I1) (wherein, X
is an oxygen atom or a sulfur atom, and P, m, and n represent an integer of 0 or l. However, at least one of 2, P, 11I, and n is 1, and m and rl are not 1 at the same time.

) and the aldehydes represented by ---Funenin (I) (in the formula, R8
and R2 are the same as R and R2 in general formula (I). ) or its mineral acid salt in a suitable solvent (e.g. methanol, ethanol,
It can be easily obtained by reacting with 1,4-dioquinane, tetrahydrofuran, N,N-dimethylformamide, acetic acid).

The hydrazone compound of the present invention is used as a charge transporting substance in combination with a charge generating substance to form an electrophotographic photoreceptor.

As the charge-generating substance, any substance that has charge-generating ability can be used, including selenium, selenium alloys,
Examples include inorganic materials such as phosphorus, cadmium sulfide, and organic dyes and pigments such as phthalocyanine, perylene, perinone, indigo, amyllaquinone, cyanine, and ab-based dyes.

Since the hydrazone compound of the present invention does not have film-forming ability by itself, it is used in combination with a binder to form a photosensitive layer.

An insulating polymer is used as the binder, but
Examples include polystyrene, polyacrylamide, polyvinyl chloride, polyester resin, polycarbonate resin, epoxy resin, phenokine resin, polyamide resin, and the like.

In particular, polyester resins and polycarbonate resins can be suitably used. Poly N-vinyl carhadur, which itself has charge transport ability, can also be used as a binder.

As shown in Figure 1, the photoreceptor has a structure in which a charge generating substance and a charge transporting substance are contained in the same layer on a conductive support, and as shown in Figure 2, a charge generating substance and a charge transport substance are contained in the same layer on a conductive support. There are those in which a charge generation layer containing a charge generation substance is formed and a charge transport layer containing a charge transport substance is laminated thereon, and those in which a charge generation layer and a charge transport layer are laminated in reverse.

Although any of the photoreceptors having the above configurations are effective in the present invention, the laminated type photoreceptor shown in FIG. 2 is preferred since it provides excellent electrophotographic properties.

The structure of the photoreceptor will be explained in more detail using FIG. 2 as an example.

As the conductive support, a metal plate made of aluminum, copper, zinc, etc., a plastic sheet or plastic film made of polyester, etc., on which a conductive material such as aluminum, SnO□, etc. is vapor-deposited, or conductively treated paper, etc. are used.

The charge generation layer can be formed by various methods such as vacuum deposition of a charge generation substance on a conductive support, coating and drying a solution of a charge generation substance, and coating and drying a fine particle dispersion of a charge generation substance. The charge generation layer can be formed by selecting a charge generation material by any method. The thickness of the charge generation layer is preferably 0.01 to 5μ, more preferably 0.0μ.
It is 5 to 2μ.

If the thickness is less than 0.01 μm, charge generation will not be sufficient, and if it exceeds 5 μm, the residual potential will be high and it is not practical.

The charge generation layer is formed by mixing and dissolving the hydrazone compound of the present invention and the binder in an appropriate organic solvent, coating and drying. The charge transport layer contains a charge transport material in an amount of 10 to 95%,
It is preferably contained in an amount of 30 to 90% by weight. If the amount of the charge transport material is less than 10% by weight, charge transport will hardly occur, and if it exceeds 95% by weight, the mechanical strength of the photoreceptor will be poor, which is not preferred in practice.

Further, the thickness of the charge transport layer is preferably 3 to 50μ, more preferably 5 to 30μ, and this thickness is 3 to 50μ.
If it is less than 50μ, the amount of charge will be insufficient, and if it exceeds 50μ, the residual potential will be high and it is not practical.

Further, an intermediate layer can be provided between the photosensitive layer and the conductive support, and the material thereof is suitably polyamide, nitrocellulose, casein, polyvinyl alcohol, etc., and the film thickness is preferably 1 μm or less.

As described above, the electrophotographic photoreceptor of the present invention has the following advantages:
In addition to the bitrazone compound in I), the photoreceptor is composed of the conductive support, charge generating substance, binder, etc., but other components of the photoreceptor may have functions as components of the photoreceptor. It is not particularly limited.

(Functions and Effects) The electrophotographic photoreceptor of the present invention has high sensitivity and excellent performance that does not deteriorate with repeated use by using the bitrazone compound represented by formula (I) as a charge transport material. has.

(Margins below) [Examples] The present invention will be specifically described below with reference to Examples, but the embodiments of the present invention are not limited thereto.

Production Example 1 Synthesis of Exemplified Compounds No. 2 1.5 g of an aldehyde compound represented by the following structural formula was dissolved in 20 ml of N,N-dimethylformamide, and 1.7 g of 1,1-diphenylhydrazine hydrochloride was dissolved in N,N-dimethylformamide. A solution dissolved in N-dimethylformamide 20 was added dropwise at room temperature and stirred for 3 hours. After confirming the disappearance of the raw material aldehyde, methanol and water were added, and the precipitate was filtered and dried. Recrystallization from chloroform-ethanol gave bright yellow needle crystals (melting point 185-186°C; λ1I11. (CIIC
I3) 388nm) 2.0 g was obtained. This product was confirmed to be Exemplified Compound No. 2 by elemental analysis.

Elemental analysis value 0111 Actual measurement value (χ) 80,14 4.73 10.82
Calculated value (χ) 80,21 4.88 10.80
Production Examples 2 to 12 Hydrazone compounds were synthesized in the same manner as Production Example 1 using the corresponding aldehyde compounds and hydrazine compounds as raw material 4. The analytical values and physical property values of the obtained compound are shown in Table 2.

Example 1 Polyester resin (manufactured by Toyobo Co., Ltd., product name [) Ikon 2]
00J O, 0.5 g of a disazo dye represented by the following structural formula (CG-1), and 50 g of tetrahydrofuran were ground and mixed in a ball mill, and the resulting dispersion was placed on an aluminum plate using a Tsuyer bar. Approximately 0.5 after coating and drying at 80°C for 20 minutes.
A charge generation layer of μ was formed.

Exemplary compound No. 10 1 g, polycarbonate resin (trade name [Panlite L1300J
A solution of Ig (manufactured by Teijin Kasei) dissolved in 10 g of chloroform was applied using a wire bar, and dried at 80°C for 30 minutes to form a charge transport layer with a thickness of about 18 μm, resulting in the laminated type shown in Figure 2. A photoreceptor was produced.

Electrostatic copying paper testing device (■Kawa [1 Denki Seisakusho model pp
A-8100), the photoreceptor was charged by corona discharge at an applied voltage of -iV, the surface potential V at that time was measured, and after being left in a dark place for 2 seconds, the surface potential ν2 at that time was measured, and then With the surface illuminance of the photoconductor at 51ux, irradiate it with light from a halogen lamp (color temperature 2856°K), measure the time for the surface potential to reach 2 of v2, and calculate the half-reduced exposure amount E.
'A (lux -5ec) was calculated.

Furthermore, the surface potential V12, ie, the residual potential, was measured after 10 seconds of light irradiation. Furthermore, the charging exposure operation was repeated 1000 times.

Example 2 A photoreceptor was prepared in the same manner as in Example 1, except that a disazo dye (cc-2) represented by the following structural formula was used, and the same measurements were carried out.

Example 4 A photoreceptor was prepared in the same manner as in Example 1, except that a tetrakisazo dye represented by the following structural formula (CG was used as a charge-generating substance and Exemplary Compound No. 5 was used as a charge-transporting substance) I took measurements.

Example 3 Disazo dye (CG-3) represented by the following structural formula was used as a charge-generating substance, Exemplary Compound No. 1 was used as a charge-transporting substance, and Exemplary Compound No. 36 was used as a charge-transporting substance. A photoreceptor was produced in the same manner as in Example 1, except that the photoreceptor was measured in the same manner as in Example 1.

Example 5 A photoreceptor was prepared in the same manner as in Example 1, except that τ-phthalocyanine (CG-5) was used as a charge generating substance and Exemplified Compound No. 6 was used as a charge transporting substance, and the same measurements were carried out.

Examples 6 to 24 Photoreceptors were prepared in the same manner as in Example 1, using different charge-generating substances and charge-transporting substances, and the same measurements were performed.

The combinations of charge generating substances and charge transporting substances used and the measurement results are shown in Table 3 together with the measurement results of Examples 1 to 5.

Comparative Example 1 The above disazo dye (CG-3) was used as a charge generating substance, and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole (CT1) was used as a charge transporting substance.
A photoreceptor was produced in the same manner as in Example 1, except that the photoreceptor was used, and the same measurements were performed. The measurement results are shown in Table 3.

Examples 25 to 27 The photoconductors prepared in Examples 4.9 and 24 were each attached to a commercially available electrophotographic copying machine to make copies, and even on the 10,000th copy, clear images with no fogging that were faithful to the original were obtained. Obtained.

As described above, it can be said that the electrophotographic photoreceptor using the hydrazone compound of the present invention has high sensitivity and stable performance even after repeated use, and is also excellent in durability.

The photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in various printers, electrophotographic engraving systems, etc. that apply electrophotographic copying principles.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing an example of the structure of an electrophotographic photoreceptor. In FIG. 1 and FIG. 2, each reference symbol is as follows.

Claims (1)

[Claims] The photosensitive layer on the conductive support has the general formula (I) ▲mathematical formula, chemical formula, table, etc.▼ (I) (wherein, X is an oxygen atom or a sulfur atom, and R_1 and R_2 is an optionally substituted alkyl group, aralkyl group, or aryl group, and at least one is an optionally substituted aryl group.l, m, and n are 0 or 1
represents an integer. However, at least one of l, m, and n
one is 1, and m and n are not 1 at the same time. ) An electrophotographic photoreceptor comprising a hydrazone compound represented by: