JPS63125945A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body which is controlled the increase of potential at a light part, and the change of potential at a dark part, even in case of a repeated use by providing a specific under coating layer between a conductive substrate body and a photosensitive layer. CONSTITUTION:In the titled body provided the under coating layer and the photosensitive layer on the conductive substrate body, the under coating layer is composed of a polymer having a benzidine derivative shown by formula I as a pendant. In formula I, R1, R2, R3 and R4 are each alkyl group and may be the same or the different with each other and is methyl, ethyl or propyl group. The thickness of the under coating layer is usually 0.1-10.0mu, further preferably, 0.5-5.0mu. The under coating layer is formed by applying by means of a dip coating, a spray coating or a roll coating method, etc. Thus, the titled body which is controlled effectively the increase of potential at the light part and the change of potential at the dark part, even in case of a repeated use is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor in which a specific subbing layer is provided between a conductive substrate and a photosensitive layer.

[Prior Art] Generally, a Carlson type electrophotographic photoreceptor is
In order to form images with constant image density and no background smearing when exposure is repeated, the stability of the dark area potential and bright area potential is important.

For this reason, it has been proposed to provide a layer having the function of a barrier layer between the photosensitive layer and the conductive layer.

On the other hand, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed.In general, the charge generation layer is an extremely thin layer, for example, about 0.5 layer thick, on the conductive layer. Because of this, very slight defects, dirt, deposits, scratches, etc. on the surface of the substrate cause the thickness of the charge generation layer to be non-uniform. If the thickness of the charge generation layer is non-uniform, uneven sensitivity will occur in the photoreceptor, so it is required to make the thickness of the charge generation layer as uniform as possible.

For this reason, it has been proposed to provide an undercoat layer between the charge generation layer and the conductive layer, which functions as a barrier layer and an adhesive layer.

Until now, has it been known to use polyurethane, polyamide, polyvinyl alcohol, epoxy resin, casein, methylcellulose, nitrocellulose, or phenolic resin as an undercoat layer between the photosensitive layer and the conductive layer? When an electrophotographic photoreceptor is used in reverse, it tends to cause an increase in the bright area potential and a fluctuation in the dark area potential.Especially in a low temperature and low humidity environment, the bright area potential increases significantly, and if used continuously, the image quality will not be constant. It had the disadvantage that it was not possible to obtain copies with

[Problems to be Solved by the Invention] The purpose of Kokuhatsu 1y7 is to provide an electrophotographic photoreceptor that suppresses increases in bright area potential and fluctuations in dark area potential even after repeated use.

[Means for Solving the Problems] The present invention provides an electrophotographic photoreceptor in which at least an undercoat layer and a photosensitive layer are provided on a conductive substrate, which is characterized in that it is composed of a polymer having the undercoat layer pendant. shall be. However, in the above formula, R1, Ra.

R's and R4 are alkyl groups, which may be the same or different, and are a methyl group, an ethyl group, or a propyl group.

Polymers having the above-mentioned benzidine derivatives pendant are known as redox polymers, and taking 2-vinyl-N,N,N',N'-tetramethylbenzidine polymer as an example, the polymer has a reversible polymer as shown in the following formula. It is known to exhibit oxidation-reduction properties.

Conventionally, the electrical conductivity of the resins used in the undercoat layer is either ion conduction or plays an important role.At low temperature and low humidity, the electrical conductivity decreases, and the electrical conductivity of the resins generated in the photosensitive layer is efficiently separated and transferred to the substrate. It is thought that the bright area potential increases and the dark area potential fluctuates because the light does not escape to the side.

In contrast, such a phenomenon does not occur in the electrophotographic photoreceptor of the present invention.

If the undercoat layer is made of a polymer with pendant benzidine derivatives that have electron transfer properties, electrons generated in the photosensitive layer can easily be transferred to the substrate side in the case of an electrophotographic process in which holes are transferred as majority carriers. This is probably because they can escape.

Examples of the structure of Bommer having a pendant benzidine derivative used in the present invention include the following structures.

In the formula, R1, R, , R, and R4 represent alkyl groups such as methyl, ethyl, and propyl, which may be the same or different as described above.

The above-mentioned effect of transmitting electrons and escaping them to the substrate side is expected to occur even if the benzidine derivative itself is mixed into the binder to form an undercoat layer. It was difficult to obtain stable effects due to problems such as elution when laminated. In the present invention, since the benzidine derivative is contained in the polymer skeleton, the above-mentioned problems such as compatibility, film formability, and elution do not occur.

The undercoat layer usually has a thickness of 0.1 to 10,000 yen, preferably 5 to 5,000 ml, and is applied by dipping coach ink, spray coating, roll coating, or the like.

In the third aspect of the present invention, the photosensitive layer may be of a single layer type or may be of a laminated structure type in which a charge generation layer and a charge transport layer are separated.

The charge generation layer is made of azo pigments such as Sudan Red, Diane Blue, and Jenas Green B, Algol Yellow,
Quinone pigments such as pyrenequinone and indanthrene brilliant violet RRP, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, bisbenzimitazole pigments such as India First Orange toner, phthalocyanine pigments such as copper phthalocyanine, quinacridone pigments, etc. The charge generating material is dispersed in a binder resin such as polyvinyl butyral, polystyrene, polyvinyl chloride, polyvinyl acetate, acrylic, polyvinylpyrrolidone, methyl cellulose, hydroxypropyl methyl cellulose, etc., and this dispersion is applied onto the undercoat layer described above. It can be formed by coating.

The thickness of such a charge generation layer is usually 5 µl or less, preferably 0.01 to tp.

The charge transport layer provided on the charge generation layer includes anthracene,
Polycyclic aromatic compounds such as pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, thiadiazole,
It is formed using a coating liquid in which a charge-transporting substance such as a nitrogen-containing cyclic compound such as triazole or a hydrazone compound is dissolved in a resin with film-forming properties. This is because the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself. Examples of such resins include polyester, polysulfone, polycarbonate, polymethacrylates, polystyrene, and the like. The thickness of the charge transport layer is usually about 5 to 20 mm.

As the photosensitive layer used in the present invention, other than the above-mentioned poly-N-
Examples include a layer of an organic photoconductive polymer such as vinylcarbazole or polyvinylanthracene, a selenium vapor deposited layer, a selenium-tellurium vapor deposited layer, or an amorphous silicon layer.

The substrate used in the photoreceptor of the present invention may be any substrate as long as it has a conductive layer, and specific substrates include:
For example, aluminum, copper, vanadium, molybdenum, chromium, nickel, and titanium.

Zinc, indicum, brass, etc. molded into a drum or sheet shape, aluminum, copper, or other metal foil laminated to a plastic film, aluminum, indium oxide, tin oxide, etc. deposited on a plastic film, or metal powder Examples include plastic films and paper whose surfaces are coated with a conductive substance such as carbon black, copper iodide, or a polymer electrolyte together with a suitable binder resin and subjected to conductive treatment.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers,
It can be used in electrophotographic plate making systems, etc.

[Example] Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A coating solution for an undercoat layer was prepared by dissolving 10 g of 2-vinyl-N,N,N',N'-tetramethylbenzidine polymer having the following structure in 90 g of tetrahydrofuran.

Next, prepare an aluminum cylinder of 60 φ x 260 m + * as a base, apply the following coating solution on the cylinder so that the film thickness is 2.0 m, and heat it at 60°C for 3
An undercoat layer was formed by drying for 0 hours.

Next, 10 parts of a disazo pigment having the following structure (by weight,
The same applies hereinafter), 6 parts of cellulose acetate butyrate resin (trade name: CAB-381+manufactured by Eastman Chemical Co.), and 60 parts of cyclohexanone were dispersed in 2 parts using a Santomill trowel using 1φ glass beads. 100 parts of methyl ethyl ketone was added to this dispersion, which was dip coated onto the undercoat layer and dried by heating at 100° C. for 10 minutes.

A charge generation layer with a coating i of 0.1 g/+s was provided.

Next, 10 parts of a hydrazone compound having the following structure and a styrene-methyl methacrylate copolymer resin (trade name: MS
200 (manufactured by Seitetsu Kagaku Co., Ltd.) was dissolved in 80 parts of toluene. This solution was coated on the charge generation layer, and
Hot air drying was performed at 0° C. for 1 hour to form a charge transport layer with a thickness of 16 μl, thereby obtaining an electrophotographic photoreceptor.

Comparative Example An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that alcohol-soluble nylon (trade name: Amilan CM-8000, manufactured by Toshi Co., Ltd.) was used as the resin for the undercoat layer.

Each of the electrophotographic photoreceptors produced in this way was
An electrophotographic copying machine that includes kV corona charging, image exposure, dry toner development, toner transfer to plain paper, and a leaning process using a urethane rubber blade (hardness 70°, pressure 10 gw/c blade, angle 20° relative to photoreceptor). was installed to evaluate the electrophotographic characteristics. The results are shown in the table below.

When 1000 images were continuously produced in a low temperature, low humidity environment (15°C/10%), the electrophotographic photoreceptor according to the example effectively suppressed increases in bright area potential and fluctuations in dark area potential, and was extremely stable. An image was obtained.

Example 2 Same as Example 1, 2-vinyl-N, N, N', N
A coating solution for an undercoat layer was prepared by dissolving 10 g of '-tetramethylbensidine polymer in 90 g of tetrahydrofuran.

Apply the above coating solution to the north of a 60φ x 260m aluminum cylinder with a film thickness of 2. An undercoat layer was formed by dip-coating in a uniform pattern and drying at 60°C for 30 minutes.

Next, 10 parts of ε-type copper phthalocyanine pigment with the following structure, butyral resin (trade name BM-2, manufactured by Sekisui Chemical Co., Ltd.) and 60 parts of cyclohexanone were dispersed for 20 hours in a sand mill using lφ glass beads. 100 parts of methyl ethyl ketone was added to this dispersion, and the mixture was dip coated onto the undercoat layer, and dried by heating at 00''C for 10 minutes.
A charge generation layer was provided at a coating weight of 0.1 g/12.

Next, 10 parts of a hydrazone compound having the structure shown below and 15 parts of a styrene-methyl methacrylate copolymer resin (trade name MS-200, manufactured by Seitetsu Kagaku Co., Ltd.) were dissolved in 80 parts of toluene. This solution was applied onto the charge generation layer and dried with hot air at 100"C for 1 hour.
= thick charge transport layer was formed.

The electrophotographic photoreceptor produced in this way was -5,6k
V corona charging, semiconductor laser (oscillation wavelength 790 nu
) Image exposure, dry toner reversal development, +4. Used in laser beam printers with processes such as OkV transfer charging, urethane rubber blade cleaning, and pre-exposure.
The photographic characteristics of the child were evaluated. Low temperature, low humidity environment (15°C
/10%) When I output 1000 consecutive images below,
Both the rise in the bright area potential (the black area on the image) and the fluctuation in the dark area potential were effectively suppressed, and a very stable image was obtained.

Example 3 Same as Example 1, 2-vinyl-N, N, N', N
A coating solution for an undercoat layer was prepared by dissolving log '-tetramethylbensidine polymer in 90% of tetrahydrofuran.

On the other hand, 20 parts of conductive titanium oxide, 40 parts of phenol resin, and 20 parts of methyl cellosolve were placed on an aluminum cylinder of 60φ x 260 mm as a base.

A paint consisting of 20 parts of methanol was applied by dip coating to a film thickness of 20 liters, and dried at 140°C for 30 minutes to form a conductive layer. On top of that, apply the above coating solution to a film thickness of 2. An undercoat layer was formed by coating the film in an immersion layer so as to form an OuL layer and drying it at 60"C for 30 minutes.

Next, 10 parts of a disazo pigment having the following structure, 6 parts of butyral resin (trade name BM-2, manufactured by Ueki Kagaku Kogyo Co., Ltd.) ! &
Then, 60 parts of cyclohexanone was dispersed for 20 hours using a Santo Mill apparatus using 1φ glass beads.

100 parts of methyl ethyl ketone was added to this dispersion, which was applied onto the undercoat layer by dip coating, and dried by heating at 100'C for 10 minutes to form a charge generating layer with a coating weight of 1 g/m''.

Next, 10 parts of a hydrazone compound having the following structure and a styrene-methyl methacrylate copolymer resin (trade name: MS
-200, manufactured by Steel Chemical Co., Ltd.) 15 parts to 80 parts of toluene
It was dissolved in parts.

Next, this liquid was applied onto the charge generation layer and dried with hot air at 100°C for 1 hour to form a charge transport layer having a thickness of 16 μl.

The electrophotographic properties of the thus produced electrophotographic photoreceptor were evaluated using a laser beam printer in the same manner as in Example 2.

1000 continuous cycles under low temperature and low humidity environment (15°C/10%)
When a single image was produced, both the increase in bright area potential and the fluctuation in dark area potential were effectively suppressed, and a very stable image was obtained.

[Effects of the Invention] According to the present invention, it is possible to provide an electrophotographic photoreceptor that effectively suppresses increases in bright area potential and fluctuations in dark area potential even after repeated use.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor comprising at least an undercoat layer and a photosensitive layer provided on a conductive substrate, wherein the undercoat layer is composed of a polymer having a benzidine derivative pendant.