JPH02259766A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance electrification characteristics of a photosensitive body and to restrain deterioration of sensitivity due to repeated uses by incorporating a specified hydrazone compound in a photosensitive layer. CONSTITUTION:The photosensitive layer of this photosensitive body contains the hydrazone compound represented by formula I in which R1 is alkyl, aryl, or the like; R2 is H, alkyl, or the like; R3 is H, alkyl, or the like; R4 is alkyl, aralkyl, or the like; and each of R5 - R8 is H, alkyl, or the like. The photosensitive layer can be formed by laminating on a conductive substrate a carrier generating layer containing a desired bisazo pigment or the like and a carrier transfer layer containing the hydrazone compound of formula II or the like.

Description

Detailed Description of the Invention Country Industrial Field of Application The present invention relates to an electrophotographic photoreceptor containing a novel hydrazone compound. Photoconductive materials such as selenium, cadmium sulfide, lead oxide, and silicon are well known, and have been extensively studied and put into practical use. In recent years, in contrast to inorganic materials, research into organic photoconductive materials has progressed actively, and some have been put into practical use as electrophotographic photoreceptors.

Generally speaking, inorganic materials have problems such as thermal stability, deterioration of properties due to crystallization, and manufacturing difficulties in selenium photoreceptors, and moisture resistance, durability, and industrial waste in the case of cadmium sulfide. In contrast, organic materials have good film-forming properties, excellent flexibility, light weight, and transparency. Since it has advantages such as the ease of designing a photoreceptor for a wide range of wavelengths by using an appropriate sensitization method, its practical application is gradually attracting attention.

By the way, photoreceptors used in electrophotography are generally required to have the following basic properties.

That is, (υ has high charging property against corona discharge in the dark, (2) has little leakage (dark loss tl) of the obtained charged charge in the dark, and (3) has a high chargeability due to light irradiation. (4) The residual charge after light irradiation is small.

However, to date, much research has been conducted on photoconductive polymers such as polyvinylcarbazole as organic photoconductive materials, but these do not necessarily have sufficient film properties, flexibility, or adhesion properties, or It cannot be said that the above-mentioned basic properties as a photoreceptor are sufficiently provided.

On the other hand, for organic low-molecular-weight photoconductive compounds, it is possible to obtain photoreceptors with excellent mechanical strength such as film properties and adhesive flexibility by selecting the crushing agent used for forming the photoreceptor. However, it is difficult to find suitable compounds that can maintain high sensitivity properties.

In order to improve these points, an organic photoreceptor having higher sensitivity characteristics has been developed by assigning the functions of carrier generation and transport to different substances. A feature of this kind of photoreceptor, which is called a functional separation plate, is that materials suitable for each function can be selected from a wide range, and since it is possible to easily create a photoreceptor with arbitrary performance, it has been the subject of much research. has been underway for nine years.

(Q. Purpose of the Invention As mentioned above, various improvements have been made in the production of electrophotographic photoreceptors, but the basic properties required for photoreceptors as mentioned above and the requirements such as high durability) An object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity and high durability.In particular, the photoreceptor of the present invention has a high charging property. It is an object of the present invention to provide a W4 optical body which has a high charging potential, almost no decrease in sensitivity even after repeated use, and a stable charging potential.

■ Structure of the Invention As a result of research into photoconductive substances with high sensitivity and high durability, the present inventors discovered that a novel hydrazone compound represented by the following general formula (il) is effective. reached.

(In the formula, R is an alkyl group that may have a substituent,
Aralkyl group, aryl group k, R1 is hydrogen, alkyl group, alkoxy group 'ts Rs is hydrogen, alkyl group, aryl group, R4 is alkyl group, aralkyl group, aryl group which may have a substituent, R1, R, and R,
R, may be the same or different, and each represents hydrogen, an alkyl group, an aralkyl group, or an aryl group which may have no substituents. Also, RI and R6 or R1
and R8 may each form a ring. n narrows 0 or 1. ) Here, specific examples of the substituent R8 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, Hensyl group, β-phenylethyl group, P-methylbenzyl group,
Examples include aralkyl groups such as P-methoxybenzyl group and α-7termether group, and aryl groups such as phenyl group, naphthyl group, tolyl group, quinryl group, chlorophenyl group, thoxyphenyl group, and methylnaphthyl group.
Specific examples of the substituent R2 include a hydrogen atom, alkyl groups such as a methyl group, ethyl group, and propyl group, and alkoxy groups such as a methoxy group, ethoxy group, and propoxy group; specific examples of the substituent R3 include can include a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a propyl group, an aryl group such as a phenyl group, a tolyl group, a methoxyphenyl group, a chlorophenyl group, and the substituent R4
Specific examples include methyl group, ethyl group, propyl group,
Alkyl groups such as butyl groups, aralkyl groups such as benzyl groups, β-phenylethyl groups, chlorobenzyl groups, methylbenzyl groups, dibenzyl groups in meth, α-su7thylmethyl groups, phenyl groups, naphthyl groups, methoxypher groups,
Examples of substituents R1, R@, R1, and "a" include hydrogen atom, methyl group, ethyl group, and propyl group. Alkyl groups such as
Examples include aralkyl groups such as benzyl group and β-phenylethyl group, and aryl groups such as phenyl group, methoxyphenyl group, ethoxyphenyl group, tolyl group, xylyl group, and chlorophenyl group.

These human dicine compounds represented by the formula (1) can be produced by the following synthesis method. Compound (c) (Rs = C
l bird = R1 = book R4 = Ph% R, = R, = 4-
Synthesis of CH,0-phSn==Q).

Compound (a) (R1=CH,,R,=R,=H1R7
=R, =4-CH,0-PhS! L=O:) 0.7
47 g and 0.238 # of phenylhydrazine are refluxed in 5 d of ethyl alcohol for 1 hour. Separate the precipitated crystals and wash them with ethyl alcohol. Compound (c
) got 1.

NMR (δ, ppm, DMS O-d, )2.8
2 (S, 3H), a, 7s (s, au), 6.56 (S
, LH), 6.71 (m, LH), 6.8-7.2 (m
, 14H), 7.54 (α, J = 8.7 Hz,
2H), 7.82 (S, IH), 10.6 (S, IH)
Next, exemplified compound (16) was synthesized from compound (c) obtained above.

Compound (c) 0.69511, bis(4-methoxyphenyl)acetaldehyde 0.4231 and kp-)luenesulfonic acid monohydrate (10 liters) are refluxed for 3 hours in 25 d of benzene. After the reaction, the benzene gold was distilled off, and the crude product was purified using a silica gel column (hexane: ethyl acetate = 3
:1) Do. Yellow crystals with a melting point of 91.0-95°0.0.
770 g of compound (16) was obtained.

NMR (δ, pprILSDMSO-d, )2.81
(S, 3H), 3.66 (S, 3H), 3.78 (S.

6■), 3.82 (S, 3H), 6.39 (S, LH)
, 6.56 (S, IH), 6.7-7.2 (m, Zl)
, 7.36 (d, J=8.7Htt, 2H), 7.
60 (a, J=8.7Hz, 2H), 7.95
(S, LH) Next, all examples of hydrazone compounds related to the present invention will be shown, but the invention is not limited to them. It is obtained by containing more than 1 type, and the excellent performance is completely blind.

Various methods are known for using these hydrazone compounds as an all-electrophotographic photoreceptor. A conductive support in the form of a photoreceptor in which a binder resin is added and dissolved or dispersed in a binder resin and provided on a conductive support, or in the form of a laminated structure consisting of a carrier generation J- and a carrier transport J-. On top, a carrier generation layer with high carrier generation efficiency, for example, a carrier generation layer mainly composed of dye or pigment,
This hydrazone compound is added as a chemical sensitizer or electron-attracting gold as required, and is commonly known as or dispersed in an N binder resin. , its carrier generation layer, carrier transport layer and all 4
There are photoreceptors that are laminated in reverse on an electrically conductive support.
It is possible to apply to any case of n.

As a support for producing a photoreceptor using the compound of the present invention, a metal drum, a metal plate, a conductive processed paper, a plastic film, a T-ebelt type support, etc. are used.

Various types of film-forming resins can be used for photosensitive printing on these supports, depending on the field of use. For example, in photoconductor applications for copying, polystyrene resin, polyvinyl acetal resin, polysulfone resin5. Examples include polycarbonate resin, vinyl acetate/crotonic acid copolymer resin, polyphenylene oxide resin, polyester resin, alkyd resin, polyarylate resin, acrylic resin, methacrylic resin, and phenoxy resin. Among these, polystyrene resins, polyvinyl acetal resins, polycarbonate resins, polyester resins, polyarylate resins, phenol resins, and the like have excellent potential characteristics as photoreceptors.

In addition, these resins may be used alone or as a copolymer.
A mixture of more than one species can be used.

The amount of i added to the photoconductive compound of these binder resins is 0.2 to 10 times by weight, preferably 0.
．． In the range of 5 to 5 times, if the amount is less than this, the photoconductive compound will precipitate in the photosensitive material or on the surface, resulting in poor adhesion to the support, and if the amount is too much, the sensitivity will decrease.

Next, some of the film-forming disinfectant resins used are rigid and weak in mechanical strength such as tension, bending, and compression, so it is necessary to add a substance that imparts plasticity to improve these properties. These substances include phthalate esters (e.g., DOP, DBP, DIDP, etc.), phosphate esters (e.g., TCP, TOP, etc.), cinanoate (sinate, adipate, nitrile rubber, chlorinated hydrocarbons, etc.) When adding these plasticizing substances, it is preferable that the proportion of these substances added to the eyebrow agent resin be 20% or less by weight, since adding more than necessary will cause deterioration of the potential characteristics.

Next, the sensitizing dyes added to the photosensitive layer include V, triphenylmethane dyes such as methyl violet, crystal violet, ethyl violet, night blue, and Victoria blue, erythrosine, rhodamine B, rhodamine 3B1, and acridine red. xanthene dye represented by B, etc., acridine dye represented by Acridine Orange 2G, Acridine Orange R, 7 Labeosi 7, etc., thiazine dye represented by methylene blue, methylene green, fog blue, Melt Lab-
Other examples include oxazine dyes such as cyanine dyes, styryl dyes, biryllium salts, thiapyrylium salts, and squareium salts.

In addition, in the photosensitive layer, examples of tetraelectric pigments that generate carriers with extremely high efficiency through light absorption include metal-free phthalocyanines, phthalocyanine pigments such as phthalocyanine enclosing various types of gold) A4 or metallized 9J; These include perylene pigments such as helilene imide and perylenic anhydride, as well as quinacridone pigments, anthraquinone pigments, and azo pigments.

Among these pigments, those using bisazo pigments, trisazo pigments, and phthalocyanine pigments, which have particularly high carrier generation efficiency, provide high sensitivity and provide excellent electron beams.

Furthermore, although the aforementioned dye added to the photosensitive layer can be used alone as a carrier-generating substance, carriers may be generated with even higher efficiency by coexisting with a pigment. Further, as the inorganic photoconductive substance, selenium, selenium tellurium association, cadmium sulfide, zinc sulfide, amorphous silicon, etc. are necessary.

In addition to the sensitizers mentioned above (so-called spectral N sensitivity A1), it is also possible to add sensitizers (so-called chemical sensitizers) for the purpose of further improving sensitivity.

Examples of the sensitizer include p-chlorophenol, m-chlorophenol, p-nitrophenol, 4-chloro-
m-cresol, p-chlorobenzoylacetanilide, N I N'-diethylbarbyl [,3-(β-
oxyethyl)-2-7 2-2 iminotheazolidone,
Malonic acid dianilide, 3.5.3'l5'-tetrachloromalonic acid dianilide, α-naphthol, p-
Examples include nitrobenzoic acid.

Furthermore, an electron-withdrawing compound such as AY8 can be added as a sensitizer that forms a charge transfer complex with the hydrazone compound of the present invention and further increases the sensitizing effect.

Examples of the electron-withdrawing substance include 1-chloroanthraquinone, 1-nitroanthraquinone, 2,3-dichloro-naphthoquinone, 3,3-dinitrobenzophenone, 4
-Nitrobenzalmalonenitrile, phthalic anhydride, 3-
(';'-cyano p-nitrobenzal)phthalide, 2
, 4.7-trinitrofluorenone, 1-methyl-4-
Examples include nitrofluorenone, 47-sinitro-3,6-dimethylfluorenone, and the like.

Other additives to the photoreceptor, such as antioxidants and anti-curl agents, may be added as necessary.

The hydrazone compound of the present invention is dissolved or dispersed in a suitable solvent together with various additive substances depending on the form of the photoreceptor, and the mold solution is coated on the above-mentioned conductive support.
Examples of the coating solvent used to dry the photoreceptor include halogenated hydrocarbons such as chloroform, dichloroethane, trichloroethane, and trichloroethylene, aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, dioxane, tetrahydrofuran, and methyl. Bath additives containing a single solvent or a mixture of two or more solvents such as cellosolve, dimeterceronlube, methyl cellosolve acetate, etc.71c
If necessary, add ``arols, acetonitrile,
A solvent such as N-dimethylformamide or methyl ethyl ketone may be further added.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these in any way. Pigment 1 shown in Example 1! Mayube, 1 part by weight of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) and 100 parts by weight of tetrahydrofuran.
Parts by weight were mixed and shaken for 2 hours with glass beads using a paint conditioner to completely disperse the mixture. The thus obtained fC and pigment dispersion were applied using an applicator onto a polyester film support coated with an aluminum vaporizer, and dried to form a carrier-generated Jgi film having a thickness of about 0.2 μm.

Next, a hydrazone compound cut metal exemplified by m(3),
Polyarylate resin (Unitika U-polymer) and 1=
Dichloroethane was mixed at an it ratio of 10 as gold solvent.
% solution was prepared and the above-mentioned carrier generation) was coated with this bath solution using an applicator to form a carrier transport layer with a dry film thickness of 20μ. The electrophotographic properties were evaluated using a recording test device (5P-428 manufactured by Kawaguchi [TLL Co., Ltd.)].

The measurement conditions were: applied voltage -6KV, static power 3, and as a result, the original half-exposure E to white light during charging.
L/2 is 2.9 Lux·sec.

It showed very high sensitivity values.

Furthermore, the same device was used to evaluate repeated use. After 1,000 repetitions of π, the change in charged potential was found to be 1.000 with respect to the initial potential of 680V at the first time.
The initial potential of the test was 640 V, and it was found that the potential decrease due to repetition was small and stable, and excellent characteristics were exhibited.

Examples 2 to 6 Laminated photoreceptors were prepared in the same manner as in Example 1, except that the hydrazone compound shown in Table 1 was used in place of the hydrazone compound used in Example 1, and measurements were carried out in the same manner as in Example 1. Under the conditions, the light half-life exposure iEL/2 (lux/second) and the initial potential V o (volts) were measured, and the values are shown in Table 1. Furthermore, static electricity removal (static electricity removal light: 400 lux x white light)
After repeating 1,000 times with 1 second irradiation as one cycle, the initial potential V o (volt) and original half-reduction exposure amount E ], /2 were measured and shown in Table 1.

Table 1 Examples 7-10 A bisazo pigment having the following structure was used as a charge generating substance.

That is, 1 part by weight of this pigment and 1 part by weight of polyester resin (Vylon 200) were mixed with 100 parts by weight of tetrahydrofuran, and the mixture was dispersed by shaking with glass beads for 2 hours using a paint conditioner. The pigment dispersion thus obtained was coated on the same support as in Example 1 using a total aggregator to form a carrier-generating layer. The thickness of this thin film was approximately 0°2μ.

Next, a carrier transport layer was formed using the exemplified compounds shown in Table 2 in the same manner as in Example 1 to prepare a laminated photoreceptor. This photoreceptor was evaluated under the same measurement conditions as in Example 1.

The results are shown in Table 2◇ 2nd fitting

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a photosensitive layer containing a hydrazone compound represented by the following general formula [I] on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (In the formula, R_1 is an alkyl group, aralkyl group, or aryl group that may have a substituent, R_2 is hydrogen, an alkyl group, or an alkoxy group, and R_3 is represents hydrogen, an alkyl group, or an aryl group; R_4 represents an alkyl group, an aralkyl group, or an aryl group that may have a substituent; and R_5, R_6, R_7, and R_8 may each be the same or different. Often, hydrogen, an alkyl group which may have a substituent,
Represents an aralkyl group or an aryl group. Also, R_5 and R_
6 or R_7 and R_8 may each form a ring. n represents 0 or 1.