JPS61143763A - Laminate type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance stability of acceptance potential in repeated uses and to obtain superior durability by using an electrostatic charge transfer layer composed of a binder resin and a specified hydrazone type compd. and further contg. a phenol type antioxidant. CONSTITUTION:The charge transfer layer of the laminate type photosensitive body contains the binder resin, and as the charge transfer material at least one of hydrazone compds. represented by formula I, R1, R2 being alkyl, aralkyl, or aryl, A being an aromatic hydrocarbon group or heterocyclic group, and n being 1 or 2, or represented by formula II, R3, R4 being alkyl, aralkyl, or aryl, X, Y being H, alkyl, alkoxy, or dialkylamino, and m being 0 or 1, and in addition the phenol type antioxidant in an amt. of 5-20wt% of the charge transfer material. Such a charge transfer material favors transfer of positive holes, and deterioration of the photosensitive body often occurring when it is used negatively charged, can be prevented by using the phenol type antioxidant, thus permitting the obtained photosensitive body to be stable in characteristics, good in durability, and to be used for copying machines, as well as the photosensitive body of a laser printer etc., too.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a laminated electrophotographic photoreceptor having a charge generation layer and a charge transfer layer.

Specifically, the present invention relates to a laminated type Kameko photographic photoreceptor that has excellent repeatability and long life.

<Prior art> As photoconductive materials for electrophotographic photoreceptors, selenium,
Inorganic photoconductive materials such as cadmium sulfide, zinc oxide, or bound photoconductive materials such as polyvinyl carbazole have been used.

A so-called 凯layer photoreceptor is also used, in which a photosensitive layer containing one of these photoconductive substances is provided on a conductive substrate. A laminated photoreceptor has been developed as a highly sensitive photoreceptor and has been put into practical use. and <Km Charge transfer layers using organic materials have the advantages of flexibility and high band width peculiar to organic materials, and therefore, many studies have been conducted and some of them have been put into practical use.

However, although copies are usually obtained by repeatedly performing steps such as corona charging, image source, development, transfer, and cleaning, the photoreceptor is required to exhibit stable characteristics during these steps.

However, although laminated photoreceptors have excellent properties such as high charging performance and high sensitivity, they are still not fully satisfactory in terms of cyclic stability and service life, especially when organic charge transfer materials are used in the charge transfer layer. We have not been able to obtain products with satisfactory characteristics.

In other words, with repeated use, the surface potential decreases <
*Deterioration of electrical conductivity occurs), resulting in a decrease in image density (deterioration) in copy quality, making it unusable.

The cause of these deterioration or fatigue remains to be clarified. There are many different factors that can be considered.

<Problem to be Solved by the Invention> Generally, when a photoreceptor is used in a copying machine, it is constantly exposed to an atmosphere of corona discharge, and as the number of copies is made, it becomes more susceptible to the effects of these gases. , deterioration progresses. Therefore, in order to avoid this, measures such as exhaust gas are used to thoroughly replace the gas near the corona charger, but it is difficult to eliminate it completely.

Especially in the case of negative corona discharge, the discharge causes ozone, N
It is known that active gases such as those shown in Table 02 are generated, but their influence is large.

Therefore, when used as a photoreceptor, it is often used with a negative charge, resulting in serious problems such as deterioration or fatigue of the unit.

Means for Solving Problems〉 As a result of intensive study on improvement methods for this type of deterioration, the present inventors found that in the case of a charge transfer layer containing a specific hydrazone compound as an organic charge transfer agent, It was discovered that by including a high concentration of phenolic antioxidant in the layer, deterioration can be significantly suppressed, and as a result, the stability and durability of cyclic properties can be improved. We have now completed the present invention.

The gist of the present invention is to provide a laminated electrophotographic photoreceptor having It, a charge generation layer, and a charge transfer layer on a conductive substrate.
The charge transfer layer comprises at least a binder resin and the following general formula (1) (in the above formula, R1 and R2 may have an alkyl group, an aralkyl group, or an aryl group). , A represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, and n represents l or 2.) and the following general formula (loss (in the above formula, Rs and R6 independently represent an alkyl group, an aralkyl group, or an aryl group which may have a substituent, X and Y independently represent a hydrogen atom, an alkyl group, an alkoxy group, or a dialkylamino group, m is composed of seven or more charge transfer agents selected from hydrazone compounds represented by O or /), and a phenolic antioxidant is added in the layer to the charge transfer agent! A laminated electrophotographic photoreceptor having a 41f characteristic is that it contains a weight fraction.

The present invention will now be described in detail.

In the present invention, the charge generation layer is formed on a conductive substrate by a known method. As a charge generating substance, for example, inorganic photoconductive substances such as selenium and its alloys, cadmium sulfide, or sensitive pigments such as phthalocyanine pigments, perylene pigments, indigo pigments, quinacridone pigments, bisazo pigments, etc. These charge-generating substances are used, for example, in the form of a uniform layer formed by vapor deposition, sputtering, etc., or a layer formed by dispersing fine particles in a binder such as polyester resin, phenoxy resin, or polyvinyl butyral resin. It is formed with a film thickness of about θ, lμ to lμ.If necessary, between the conductive substrate and the charge generation layer, polyamide, polyurethane; epoxy resin,
A solid layer of aluminum oxide or the like may also be provided.

The charge transport layer is provided on the charge generation layer by a known method. The charge generation layer contains a binder resin, a charge transfer agent,
and phenolic antioxidants.

As the charge transfer agent, a hydrazone compound represented by the following general formula (1) or (II) is used.

(In the above formula, A represents an aromatic hydrocarbon group which may have a substituent, such as a phenyl group, or an aromatic heterocyclic group, such as a carbazolyl group, and RI and R1 are
Each independently represents an alkyl group, such as a methyl group, an ethyl group, an aryl group, such as a phenyl group, a naphthyl group, or an aralkyl group, such as a benzyl group, and n represents l or λ. ) (In the above formula, R1 and R4 are each independently an alkyl group, such as a methyl group, an ethyl group, an aralkyl group such as a benzyl group or an aryl group, e.g., t is a phenyl group,
represents a naphthyl group; , and n represents O or l. ) As a charge transfer agent, the compounds of the above general formulas (13 and (II)) may be used alone or in combination of two or more.

Binder resins used in the charge transfer layer of the present invention include polymers and copolymers of vinyl compounds such as styrene, vinyl chloride, acrylic esters, and methacrylic esters, phenoxy resins, polyvinyl acemer, polycarbonate, polyester, and cellulose. Resins that are compatible with the charge transfer agent, such as esters, cellulose ethers, silicone resins, urethane resins, and unsaturated polyesters, are used.

The mixing ratio of the binder resin and the charge transfer agent is such that the charge transfer agent is used in a range of 100 parts by weight of the binder resin to 10 parts by weight, preferably in the range of 0 to 10 parts by weight.

As the phenolic antioxidant used in the present invention, known ones can be used, but the phenol ring in the molecule Kt-
Those having one or more butyl groups can be preferably used. Specifically, 3. ! -sheet t7'tiludahydroxytoluene, co,≦-di-t-butylphenol, -2s6-
di-tert-butyl-ethylphenol, λj-di-butyl-butylmethylphenol, n-octadecyl-
J (4tl-hydroxy-J', j'-di-t
-monophenolic antioxidants such as butylphenyl) propionate, 2. -2'-methylene-his-(termethyl-≦-t-butylphenol).

/, j, j-) Rimetyluko, 4t, 6-) Squirrel (j
, j-sheet t-7'tilder hydroxypenzyl)
Benzene, tetrakis-[methylene-j-(j', j'
Examples include polyphenol-based antioxidants such as -sheet t-7''(chiruq'-hydroxyphenyl)gropionate]methane.

The amount added is based on 700 parts by weight of the charge transfer agent. Part by weight
It is used in a range of 0 parts by weight. If the amount added is too small, there will be no effect, and if it is added too much beyond this range, problems such as increased dark decay will occur.

Furthermore, the charge transfer layer of the present invention may contain well-known additives that improve film-forming properties and properties.

Various known conductive substrates can be used as the conductive substrate used in the present invention. Examples include metal drums and belts made of aluminum, copper, etc., and laminates and vapor deposits of these metal foils. Further examples include plastic films, plastic drums, paper, etc., which are coated with a conductive substance such as metal powder, carbon black, copper iodide, or tin oxide, together with a binder resin if necessary, to conductivity treatment.

<Effects of the Invention> The electrophotographic photoreceptor of the present invention obtained by scenting has excellent stability of charging potential during repeated use, and therefore has extremely good durability.

The electrophotographic photoreceptor of the present invention can be widely used in electrophotographic applications such as photoreceptors for printers using lasers, cathode ray tubes (GRT), etc. as light sources, as well as electrophotographic copying machines.

<Examples> Next, the present invention will be explained in more detail with reference to Examples. In the examples, "parts" indicate "parts by weight."

Implementation I/ 1 part of bisazo compound having the above structure and polyester (
Toyobosha Exhibition, Trademark Byron 20θ) was added to O parts of tetrahydro 7 lanta and dispersed with a sand glider, and after drying, the coating amount after drying was Oo
, 2jJ/d to form a charge generation layer.

On the charge generation layer thus obtained, 10 parts of N-ethylcarbazole-3-aldehyde diphenylhydrazone and a methacrylic resin (DIANAL BR manufactured by Mitsubishi Rayon Co., Ltd.) were applied.
100 parts of r, parts g and j of a dicyanovinyl compound having the following structure, and 3. j-') t 7' chilled hydroxytoluene (B HT ) / part t A solution dissolved in 900 parts of toluene was added to the dry film thickness /! A charge transfer layer was formed by applying the solution to μVc. The photoreceptor sample thus obtained was designated as /A and the characteristics of the photoreceptor were measured as follows.

First, corona discharge is performed in a dark place under the condition that the corona current flowing into the photoreceptor is one comb, and the rate is constant (/jO
2/8ea) to charge the photoreceptor, and measure the charging voltage to determine the initial charging voltage vO. Then j lu
The photoreceptor was exposed to white light with an illuminance of x, and the exposure amount required to reduce the surface potential of the photoreceptor by half of the initial charging voltage was determined as 3'2.

The results are shown in Table/.

The photoreceptor was then placed into the back of a metal box containing a corona discharger. A corona voltage of -4 KV was applied while circulating the air from the back of the box using a fan. At that time, the ozone concentration in one box was a ppm. In addition, the arrangement was such that corona ions would not flow directly into the photosensitive valley.

After being left in such a discharge atmosphere for K/-1 hour, the characteristics of the photosensitive book were measured in the same manner as above. Table 1 shows the results.
It was shown to.

Next, the amounts of BET added to the charge transfer layer were 0 parts, 2 parts, and Da parts in the same manner as in the above sample.

Samples containing 71 parts and 76 parts were prepared, and the results are shown in Table 1.

As is clear from the table, samples whose charge transfer layer does not contain BET, a phenolic antioxidant Q3, or only contain BET, which is a phenolic antioxidant, are exposed to the corona atmosphere.
A significant decrease in charging pressure after il was observed, but almost no decrease in charging voltage was observed for Samples /A, 1 /D, /E% IF, which are photosensitive images of the present invention.

Tetrakis-[methylene-j-
(j', ?-di-t-butyl-hydroxyphenyl)propione-)) methane (trade name: RGano!
/ 0 / 0-Ciba Geigy Co., Ltd.) (Example)
, or λ, -'-methylene-bis-(9-methyl-
6-t-7' tylphenol) (trade name 0AO-j,
W& light bodies were produced in the same manner except that 1 part of each of Ashland Chemical Co.) (Execution @ I3) or dilauryl thiodipropionate (ratio 1!II!') was added, and its properties were evaluated. It was measured. The results are shown in Table 1] Tsuji Example 7 bisazo compounds having the above structure and polyvinyl butyral (Sensui Kagakusha Lunisrex BH-J) 0.
After applying 3 parts to Bent Kirin SO part and dispersing it with a sand grinder, aluminum was deposited on Lt.
After drying, the amount of coating after drying is 0. Apply it so that it becomes 11/d,
A charge generation layer was formed.

On the charge generation layer thus obtained, hydrazo having the structure shown below, 9690 parts, P+JMA resin BRIj/00, BHT r part) was applied.
, Film thickness after drying the molten g dissolved in the 9θθ part of Le x y /! A photoreceptor sample 4tA was prepared by coating the photoreceptor in such a manner as to form a haze/cargo transport layer.

OH, 0 For comparison, a sample BE (comparative sample) was prepared which had a charge transfer layer having the same composition as the above except that it was 1 m11- and BHTt was not added.

For these samples, the L-body properties were evaluated in the same manner as in Example 7. The results are shown in Table 3.

Table 3 Implementation f! uj Ichijo sample/A and IO obtained in implementation fII/
We conducted a durability test using a commercially available copying machine.

In sample/A, there was no change in image quality even after making 0,000 copies. It was extremely stable with a value of 1!θσV.

On the other hand, in sample /C for ratio plate, 2 (200
After copying 0 sheets, there was a noticeable decrease in image density, and the surface potential was significantly lower than the initial value of -jJOVK to -<toov. From this result, it can be seen that the durability of L-) according to the present invention is significantly improved.

Claims (1)

[Claims] (1) In a laminated electrophotographic photoreceptor having a charge generation layer and a charge transfer layer on a conductive substrate, the charge transfer layer has at least a binder resin and the following general formula (I) ▲ Numerical formula, chemical formula, table, etc. Yes▼...(I) (In the above formula, R_1 and R_2 independently represent an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and A may have a substituent. represents an aromatic hydrocarbon group or an aromatic heterocyclic group, and n represents 1 or 2) and the following general formula (II) ▲There are numerical formulas, chemical formulas, tables, etc.▼...(II) (In the above formula In, R_3 and R_4 independently represent an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and X and Y independently represent a hydrogen atom, an alkyl group, an alkoxy group, or a dialkylamino group. The expression m is 0
or 1), and the layer contains 5% to 20% by weight of a phenolic antioxidant based on the charge transfer agent. A laminated electrophotographic photoreceptor characterized by: