JPS63125944A - 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 forming an underocoat layer with a polymer which has a phenotiazine nucleus as a pendant. CONSTITUTION:In the titled body provided at least one of the undercoat layer and a photosensitive layer on a conductive substrate, the undercoat layer is composed of the polymer having the phenotiazine nucleus as the pendant. The structure of the polymer which has the phenotiazine nucleus as the pendant is roughly classified into the structure of either binding a hydrogen atom or not at the N-position of the phenothiazine nucleus. However, the typical structure which has oxidation-reduction property and binds the hydrogen atom at the N-position of the phenothiazine nucleus is preferable. The thickness of the undercoat layer is usually 0.1-10.0mu, further preferably, 0.5-5.0mu, and said layer is applied by a dip coating, a spray coating or a roll coating method etc. Thus, the titled body which is controlled the increase of potential at the light part and the change of potential at the dark part, even in case of the 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 is necessary to provide l as a barrier layer between the photosensitive layer and the conductive layer.
It has been proposed to provide a layer with l#.

On the other hand, it has been proposed to have a laminated structure in which the photosensitive layer is mechanically separated into a charge generation layer and a charge transport layer, but generally the charge generation layer is T1. A very thin layer on top of the layer, e.g. 0.5
Since the film thickness is approximately JL, very slight defects, dirt, deposits, scratches, etc. on the surface of the substrate may cause non-uniform film thickness of the charge generation layer.

If the thickness of the charge generation layer is non-uniform, uneven sensitivity will occur in the electrophotographic photoreceptor, so it is required that the thickness of the charge generation layer be 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.

Is it 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 repeatedly, 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 when used continuously, the image quality cannot be maintained at a certain level. It had the disadvantage that it was impossible to obtain a copy of the original.

[Problems to be Solved by the Invention] An object of the invention 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, characterized in that the undercoat layer is made of a polymer. do.

Polymers having the above-mentioned fetchasin nuclei pendant are known as redox polymers and are known to transfer electrons.

In the conventional resins used in the undercoat layer mentioned above, the ionic conductivity plays a major role in conductivity, but the conductivity decreases under low temperature and low humidity, and the carriers generated in the photosensitive layer do not efficiently separate charges. It is thought that this causes the bright area potential to rise and the dark area potential to fluctuate because the light cannot escape to the substrate side.

On the other hand, according to the present invention, it is possible to effectively suppress the increase in bright area potential and the fluctuation in dark area potential.

If the undercoat layer is made of a polymer with pendant fetch-acin nuclei that have electron transfer properties, electrons generated in the photosensitive layer can be easily transferred to the substrate side in the case of an electrophotographic process in which holes are transferred as majority carriers. This is thought to be due to the possibility of missing the target.

The structure of the polymer having a pendant phenothiazine nucleus used in the present invention can be roughly divided into those with a hydrogen atom f at the N-position of the fetchasine nucleus and those without. Preferably, the structure has a hydrogen atom at the N-position and has typical redox properties.

Some of their structures are listed below, and these can be synthesized by polymerizing vinyl heptamers or by introducing them into side chains through polymer reactions.

Is the effect of transferring electrons and letting them escape to the substrate side as described above possible even if the phenothiazine itself is mixed into the binder to form an undercoat layer?
There were problems such as elution when a photosensitive layer was laminated on the upper layer, and it was difficult to obtain a stable effect. According to the present invention, since the phenothiazine structure is contained in the polymer skeleton, problems such as compatibility, film-forming properties, and elution properties do not occur.

The thickness of the undercoat layer is usually 0.1 to 10.0. , especially 0.
5 to 5.0 liters is suitable, and is applied by methods such as dip coating, spray coating, and roll coating.

In 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 by an aluminum layer.

The charge generation layer is made of azo pigments such as Sudan Red, Guianpuru, Sienna Screen B, Algol Yellow,
Quinone pigments such as pyrenequinone and indanthrene frilliant violet RRP.

Indigo pigments such as quinocyanine pigments, perylene pigments, indigo and thioindigo, bisbennymidazole pigments such as India Fast Orange toner, phthalocyanine pigments such as copper phthalocyanine, charge generation such as quinacridone pigments, S-based materials such as polyvinyl butyral, polystyrene,
Formed by dispersing in a binder resin such as polyvinyl chloride, polyvinyl acetate, acrylic, bobbinylpyrrolitone, methylcellulose, hydroxypropylmethylcellulose, etc., and coating this dispersion on the above-mentioned undercoat layer. can.

The thickness of such a charge generation layer is usually 5 μm or less.

Preferably it is 0.01 to xg or appropriate.

The charge transport layer provided on the charge generation layer includes anthracene,
Multi-edged aromatic compounds such as pyrene, phenanthrene, coronene, nitrogen-containing cyclic compounds such as indole, carbazole, oxazole, inoxazole, thiazole, imidazole, pyrazole, oxacyazole, pyrazoline, thiadiazole, tosoazole, hydrazone compounds, It is formed using a coating liquid in which a charge-transporting substance such as, for example, is dissolved in a film-forming resin. This is because charge-transporting substances generally have low molecular weights, and their film-forming properties are poor. Examples of such resins include polyester, polysulfone, polycarbonate, polymethacrylates, polystyrene, and the like. The thickness of the charge transport layer is approximately 5 to 20 μl.

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 vinyl carbazole or polyvinylanthracene, a selenium vapor deposited layer, a selenium-tellurium vapor deposit 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, indium, brass, etc. molded into a drum or sheet shape, aluminum, copper, or other metal foil laminated onto a plastic film, aluminum, indicum oxide, tin intoxication, etc. vapor-deposited onto a plastic film, or metal. Examples include plastink film and paper, which are coated with a conductive substance such as powder, carbon blank, iodized steel, or polymer electrolyte, together with a suitable binder resin and conductive treated on the surface.

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

Next, the present invention will be explained in more detail with reference to examples.

[Example] Example 1 A coating solution for an undercoat layer was prepared by dissolving poly-2-vinylfetchacinfuran in 90 g.

An undercoat layer was formed by dip-coating the above coating solution to a film thickness of 2.0 l onto an aluminum cylinder of 60 φ x 260 mm as a substrate, and drying at 60'C for 30 minutes.

Next, a disazo pigment with the following structure was added to toe (heavy pigment base, hereinafter referred to as "heavy pigment base"), and 6 parts of cellulose acetic acid resin (product name CAB-381, manufactured by Eastman Chemical Co., Ltd.) and 60 parts of cyclohexanone were added using 1φ glass beads. The mixture was dispersed for 20 hours in a Santo Mill apparatus. 100 parts of methyl ethyl ketone was added to this dispersion, and the mixture was applied by dip coating onto the undercoat layer L, and heated at 100°C for 10 minutes.
The sample was dried by heating for 0 minutes to form a charge generation layer with a coating weight of 10 and 1 g/m'.

Next, a hydrazone compound having the following structural formula is combined with 1O part.

Styrene-methyl methacrylate copolymer resin (product name M
S200: manufactured by Steel Chemical Co., Ltd.) 15 parts to 8 parts of toluene
Dissolved in 0 parts. Apply this liquid to the charge generation layer and
An electrophotographic photoreceptor was produced by drying with hot air at 100° C. for 1 hour to form a charge transport layer with a thickness of 16 μm.

Example 2 A polymer was synthesized by dehydration condensation of N-methylolacrylamide polymer and phenothiazine, and 10 g of this polymer was dissolved in 90 g of tetrahydrofuran to prepare a coating solution for an undercoat layer. Thereafter, an electrophotographic photoreceptor was manufactured in the same manner as in Example 1.

Comparative Example An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that alcohol-soluble nylon (trade name: Amilan CM-8QOQ, 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 has kV corona charging, image exposure, dry toner development, toner transfer to plain paper, re-ninta process using a urethane rubber blade (70° hardness, 10 gw/c pressure, 20° angle to the photoreceptor), etc. The electrophotographic characteristics were evaluated by attaching it to

1000 continuous cycles under low temperature, low humidity environment (15°C/10%)
When an image was produced, the photoreceptor according to the example produced a very stable image without any increase in bright area potential, and there was almost no fluctuation in dark area potential.

Example 3 A coating solution for an undercoat layer was prepared by dissolving log poly-2-vinyl fetch acyin in 90 g of tetrahydrofuran.

20 parts of conductive titanium oxide, 40 parts of phenolic resin, on a 60φ x 280mm aluminum cylinder as a base.
Coating 1 consisting of 20 parts of methyl cellosolve and 20 parts of methanol was applied by dip coating to form a film @20p, and heated at 140°C.
This was dried for 30 minutes to form a conductive layer. On top of that, apply the above coating solution to a film thickness of 2. Dip coat to obtain Og and heat at 60°C.
This was dried for 30 minutes to form an undercoat layer.

Next, 10 parts of a disazo pigment having the following structure, 6 parts of butyral resin (trade name BM-2, manufactured by Sekisui Chemical Co., Ltd.), and 60 parts of cyclohexane were dispersed for 20 hours in a Santomill apparatus using 1φ glass beads.

H Add 100 parts of methyl ethyl ketone to this dispersion, apply it on the undercoat layer by dip coating, and dry by heating at 100°C for 10 minutes to achieve a coating amount of 0. A charge generation layer of IH/m2 was formed.

Next, 10 parts of a hydrazone compound having the following structural formula and 15 parts of a styrene-methyl methacrylate copolymer resin (trade name MS-200, manufactured by Steel Chemical Co., Ltd.) were dissolved in 80 parts of toluene. 16. Apply this solution onto the charge generation layer and dry with hot air for 1 hour using ZooooC.
A thick charge generation layer was formed.

The electrophotographic photoreceptor produced in this way.

-5,6kV corona charging, semiconductor laser (oscillation wavelength 7
90 nm) image exposure, dry toner reversal development, ◆4.0
The electrophotographic properties were evaluated using a laser beam printer having processes of kV transfer charging, urethane rubber blade cleaning, and pre-exposure.

1000 continuous cycles under low temperature and low humidity environment (15°C/10%)
When I took out a single image, a very stable image was obtained, with no increase in bright area potential (black area on the image), and dark: f
The fluctuations in the B potential were also almost constant.

[Effects of the Invention] According to the present invention, it is possible to provide an electrophotographic photoreceptor in which an increase in bright area potential and a fluctuation in dark area potential are suppressed even when used upside down.

Claims (2)

[Claims] (1) An electrophotographic photoreceptor comprising at least an undercoat layer and a photosensitive layer on a conductive substrate, wherein the undercoat layer is composed of a polymer having pendant phenothiazine nuclei. : (2) The electrophotographic photoreceptor according to claim (1), wherein the phenothiazine nucleus has a hydrogen atom at the N-position: