JPH02189553A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain high sensitivity and high durability by providing a photosensitive layer contg. a specific stilbene compd. on a conductive base body. CONSTITUTION:The photosensitive layer contg. the stilbene compd. expressed by the formula I is provided on the conductive base body. In the formula I, R<1> denotes the atom group necessary forming a ring together with a nitrogen atom; R<2> denotes hydrogen, alkyl group, alkoxy group; R<3> denotes hydrogen, alkyl group, aryl group; R<4> denotes an aryl group; R<5> denotes hydrogen, alkyl group; aralkyl group, aryl group; R<6>, R<7> may be the same or different and denote hydrogen, alkyl group which may have a substituent, aralkyl group, aryl group. The photosensitive body which has high sensitivity, high durability, and high electrostatic charge characteristic, hardly degrades the sensitivity even after repetitive use and has a stable potential by electrification is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention relates to an electrophotographic photoreceptor containing a novel stilbene compound.

(B) Prior art and problems Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, zinc oxide, and silicon have been known to be used as electrophotographic photoreceptors, and have been extensively studied and put into practical use. has been done. In recent years, in contrast to these 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 difficulties in the case of cadmium sulfide. In contrast, organic materials have good film-forming properties, excellent flexibility, light weight, and transparency. Its practical application is increasingly attracting attention because it has advantages such as easy design of photoreceptors for a wide range of wavelengths using a suitable sensitization method.

By the way, the photoreceptor used in electrophotography technology is -
The following basic characteristics are required for boat fishing.

That is, (1) the charging property is high against corona discharge in the dark, (2) there is little leakage (dark decay) of the obtained charged charge in the dark, and (3) the charged charge is reduced by 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 adhesive properties, and as mentioned above, It is difficult to say that the photoconductor has sufficient basic properties as a photoreceptor.

On the other hand, with regard to organic low-molecular photoconductive compounds, it is possible to obtain photoreceptors with excellent film properties, adhesion, flexibility, and other mechanical strengths by selecting the binder used to form the photoreceptor. Although possible, it is difficult to find suitable compounds that can retain the properties of high sensitivity.

In order to improve this point, organic photoreceptors having higher sensitivity characteristics have been developed by assigning the carrier generation function and the carrier transport function to different substances. A feature of this kind of photoreceptor, which is called a functionally separated type, is that materials suitable for each function can be selected from a wide range, and a photoreceptor with arbitrary performance can be easily created, which has led to a lot of research. has been progressing.

(C) 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 listed above, high durability, etc. We still haven't been able to find anything that satisfies our needs.

An object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity and high durability. In particular, it is an object of the present invention to provide a photoreceptor that has high charging characteristics, exhibits almost no decrease in sensitivity even after repeated use, and has a stable charging potential.

(D) 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 stilbene compound shown in the following Itosen CI) is effective. This led to the present invention.

(In the formula, R1 represents an atomic group necessary to form a ring with a nitrogen atom. R2 represents hydrogen, an alkyl group, or an alkoxy group, R3 represents hydrogen, an alkyl group, or an aryl group, R4 represents an aryl group, and Rs represents Hydrogen, an alkyl group, an aralkyl group, an aryl group, R6, and R? may be the same or different, and represent hydrogen, an alkyl group, an aralkyl group, or an aryl group that may have a substituent. , R6, and R7 may form a ring. n represents O or 1.) Here, specific examples of the ring formed from R1 and a nitrogen atom, etc. include a carbazole ring, a phenoxazine ring, a phenothiazine ring, etc. ring, tetrahydroquinoline ring, etc. 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 R1 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 specific examples of the substituent R4 include: phenyl group, naphthyl group,
Examples include aryl groups such as ethoxyphenyl, tolyl, xylyl, and chlorophenyl. Specific examples of the substituent R5 include a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a benzyl group, a β-phenylethyl group, a chlorobenzyl group, a methylbenzyl group, a methoxybenzyl group, and an α- Examples include aralkyl groups such as naphthylmethyl, phenyl, naphthyl, methoxyphenyl, ethoxyphenyl, tolyl, xylyl, and chlorophenyl.

Further, specific examples of R8 and R7 include a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, and a propyl group, a benzyl group, a methylbenzyl group, a β-phenylethyl group, a chlorobenzyl group, a methylbenzyl group, and a methoxybenzyl group. basis,
Examples include aralkyl groups such as α-naphthylmethyl, and aryl groups such as phenyl, naphthyl, methoxyphenyl, ethoxyphenyl, tolyl, xylyl, and chlorophenyl.

These stilbene compounds represented by CI) are produced by the method of the following synthesis example.

Synthesis example (exemplified compound (13)) 2.49 g of aldehyde represented by formula (n) and formula (III)
) 3.34g of phosphoric acid ester shown in
2.24 g of potassium t-butoxide was added under water cooling. After 3 hours at room temperature, the reaction mixture was poured into water and extracted with ethyl acetate. The crude product was purified using a silica gel column, hexane:benzene = 3:1), and the compound (
13) was obtained in an amount of 3.70 g.

NMR (δ, ppm, DMSO) 1.52 (S, 3
H), 2.01 (S, 3H), 6.57 (S,
IH), 7.0-7.5 (m, 16H), 7.
74 (S, IH), 7.79 (d,% J=7.5
H2゜IH) (blank below) CH, -C CI-P(OCHCH)2 [■] Next, stilbene compounds related to the present invention are illustrated,
It is not limited to these.

(Hereinafter, blank spaces) H3 CH3 The electrophotographic photoreceptor according to the present invention is obtained by containing one or more stilbene compounds as shown above, and has excellent performance.

Various methods are known for using these stilbene compounds as electrophotographic photoreceptors.

For example, a photoreceptor comprising a stilbene compound and a sensitizing dye, dissolved or dispersed in a binder resin with the addition of a chemical sensitizer or an electron-withdrawing compound as necessary, on a conductive support. , or in the form of a laminated structure consisting of a carrier generation layer and a carrier transport layer, on a conductive support.
On a carrier generation layer mainly composed of a carrier generation substance with high carrier generation efficiency, such as a dye or a pigment,
A photoreceptor formed by laminating the present stilbene compound dissolved or dispersed in a binder resin with the addition of a chemical sensitizer or an electron-withdrawing compound as required, as a carrier transport layer, and its carrier generation layer. There is a photoreceptor in which a carrier transport layer and a carrier transport layer are laminated inversely on a conductive support, but it can be applied to either case.

As a support for producing a photoreceptor using the compound of the present invention, a metal drum, a metal plate, paper treated with electrical conductivity, a plastic film, or a belt-like support is used.

Various film-forming binder resins can be used to form the photosensitive layer on these supports depending on the field of use. For example, for use in photoreceptors for copying, polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, vinyl acetate/crotonic acid copolymer resin, polyphenylene oxide resin, polyester resin, alkyd resin, polyarylate resin, acrylic resin, methacrylic resin , phenoxy resin, etc. Among these, polystyrene resins, polyvinyl acecool 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 these binder resins added to the photoconductive compound is 0. The ratio is 2 to 10 times, 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 layer or on the surface, resulting in poor adhesion to the support, and if it is more than this, the sensitivity will decrease.

Next, some of the film-forming binder 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. Become.

These substances include phthalates (e.g. DO
PSDBP, DIDP, etc.) phosphate esters (e.g. T
(CP, TOP, etc.), sebacic acid ester, adipic acid ester, nitrile rubber, chlorinated hydrocarbons, etc. When adding these plasticity imparting substances, the proportion thereof is preferably 20% or less by weight relative to the binder resin, since adding more than necessary will result in deterioration of the potential characteristics.

Next, the sensitizing dyes added to the photosensitive layer include triphenylmethane dyes such as methyl violet, crystal violet, ethyl violet, night blue, and Victoria blue, erythrosine, rhodamine B10-damine 3B1 acridine red, etc. xanthene dye represented by B, etc.; acridine dye represented by Acridine Orange 2G, Acridine Orange R1 Flaveosin, etc.; thiazine dye represented by Methylene Blue, Methylene Green; Other dyes include cyanine dyes, styryl dyes, pyrylium salts, thiapyrylium salts, and squareium salt dyes.

Photoconductive pigments that generate carriers with extremely high efficiency through light absorption in the photosensitive layer include phthalocyanine pigments such as metal-free phthalocyanine, phthalocyanine containing various metals or metal compounds, perylene imide, and perylene acid anhydride. These include perylene pigments such 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 electronic photoreceptors.

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 inorganic photoconductive materials include selenium, selenium tellurium alloy, cadmium sulfide, zinc sulfide, amorphous silicon, and the like.

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

Examples of the sensitizer include p-chlorophenol, m-chlorophenol, p-nitrophe/-/I, 4-chloro-m-cresol, p-chlorobenzoylacetanilide, N,N-diethylbarbyl. acid, 3-(β
-oxyethyl)-2-phenylimino-thiazolidone, malonic dianilide, 3.5.3-. Examples include 5-tetrachloromalonic acid dianilide, α-naphthol, and p-nitrobenzoic acid.

Further, it is also possible to add a certain type of electron-withdrawing compound as a sensitizer that forms a charge transfer complex with the stilbene 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-(
α-cyano-p-nitrobenzal) phthalide, 2.4.
Examples include 7-dolinitrofluorenone, 1-methyl-4-nitrofluorenone, 2,7-sinitro-3,6-dimethylfluorenone, and the like.

Antioxidants, anti-curl agents, and the like can be added as additives to the low photoreceptor, if necessary.

The stilbene compound of the present invention is dissolved or dispersed in an appropriate solvent together with the various additives mentioned above depending on the form of the photoreceptor, and the coating solution is applied onto the conductive support described above.
Dry to produce a photoreceptor.

Coating solvents include halogenated hydrocarbons such as chloroform, dichloroethane, trichloroethane, and trichloroethylene, aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, dioxane, tetrahydrofuran, methyl cellosolve, dimethyl cellosolve,
Solvents such as methyl cellosolve acetate alone or in combination
A mixed solvent of more than one species or a solvent such as alcohols, acetonitrile, N,N-dimethylformamide, and methyl ethyl ketone may be added if necessary.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

(Left below) 1 part by weight of the pigment shown in Example 1, 1 part by weight of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.), and 1 part by weight of tetrahydrofuran.
00 parts by weight and dispersed with glass beads for 2 hours using a paint conditioner device. The pigment dispersion thus obtained is applied onto a polyester film coated with aluminum using an applicator and dried, resulting in a film thickness of 0. 2μ
A film of carrier-generating substance was formed.

Next, a stilbene compound represented by exemplified compound Nα1,
Polyarylate resin (Unitika U-polymer) and 1:
Mix at a weight ratio of 1 and 10 using dichloroethane as a solvent.
% solution and apply this solution onto the film of the carrier generating substance using an applicator to obtain a dry film thickness of 20 μm.
A carrier transport layer was formed.

The laminated electrophotographic photoreceptor thus produced was evaluated for electrophotographic characteristics using an electrostatic recording tester (5P-428 manufactured by Kawaguchi Electric).

Measurement conditions: Applied voltage -6KV, static magnetism 3° As a result, the light half-reduction exposure amount for white light during charging is 2
．． It showed a very high sensitivity value of 8 lux·sec.

Furthermore, the same device was used to evaluate repeated use.

When the change in charging potential due to 101 repetitions was calculated, 1
Compared to the initial potential of 1000 V in the 103rd test, the initial potential in the 103rd test was 960 V, and it was found that the potential decrease due to repetition was small and stable, indicating excellent characteristics.

Examples 2 to 5 Laminated photoreceptors were prepared in the same manner as in Example 1, except that the stilbene compounds shown in Table 1 were used in place of the stilbene compounds used in Example 1, and the same measurement conditions as in Example 1 were carried out. The half-light exposure E1/2 (lux seconds) and the initial potential Vo (volts) were measured, and the values are shown in Table 1. Furthermore, one cycle of charging and static elimination (static elimination light: 400 lux x 1 second irradiation with white light) is 10! After repeating the same procedure twice, the initial potential Vo (volts) and the light half-reduction exposure amount E1/
2 is shown in Table 1.

(Margin below) Examples 6-9 A bisazo pigment having the following structure was used as a charge generating substance.

That is, 1 part by weight of this pigment, 1 part by weight of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.), and 1 part by weight of tetrahydrofuran.
00 parts by weight and dispersed with glass beads for 2 hours using a paint conditioner device. The pigment dispersion thus obtained was applied onto the same support as in Example 1 using an applicator to form a carrier generation layer. The thickness of this thin film was about 0.2μ.

Next, Example 1 was prepared using the exemplified compounds shown in Table 2.
A carrier transport layer was formed in the same manner as above to create a laminated photoreceptor. This photoreceptor was evaluated under the same measurement conditions as in Example 1. The results are shown in Table 2.

(Margin below) Procedural amendment (spontaneous) “Claims” amended as shown in the attached sheet.

Page 5 of the specification, General formula.

1.Display of the incident Heisei 1 year Patent application number No. 10329 C=CH Relationship with the incident

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a photosensitive layer containing a stilbene 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 represents the atomic group necessary to form a ring with the nitrogen atom. R^2 represents hydrogen, alkyl group, alkoxy group, R^3 is hydrogen, alkyl group, aryl group, R^3
4 is an aryl group, R^5 is hydrogen, an alkyl group, an aralkyl group, an aryl group, R^6 and R^7 may be the same or different, and may have hydrogen or a substituent Represents an alkyl group, an aralkyl group, or an aryl group. Also, R
^6 and R^7 may form a ring. n represents 0 or 1. )