JPH0412366A - Flexible electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the above photosensitive body which has an excellent transfer characteristic, exhibits good surface smoothness and does not generate wrinkles and blocking and with which high-quality images and excellent productivity are obtainable by incorporating a silicone oil into a back coating layer. CONSTITUTION:The silicone oil is incorporated into the back coating layer 2. The silicone oil is preferable the compd. expressed by formula I. In the formu la I, R1, R2 denote CH3 or C6H5; m, n denote >= 1 integer. The back coating layer 2 having the excellent transfer characteristic and surface smoothness is, therefore, obtd. The imaging uniform over the entire surface is obtd. with the electrophotographic sensitive body by flash exposing in this way and, there fore, the photosensitive body having the excellent image quality and the excel lent productivity is obtd.

Description

Detailed Description of the Invention [Industrial Field] The present invention relates to an electrophotographic photoreceptor in which a photoconductive layer is formed of a photoconductive material. The present invention relates to a flexible electrophotographic photoreceptor with improved transportability during driving.

[Prior art]

Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors. Photoreceptors using such inorganic photoconductors have several advantages as well as various disadvantages. Manufacturing costs are high due to difficult conditions and wear and tear of raw materials, and the selenium vapor-deposited film itself is extremely susceptible to heat and mechanical shock, and is extremely susceptible to crystallization depending on environmental conditions.

In the case of cadmium sulfide, it is sensitive to humidity and poses a pollution problem except for photoreceptors coated with an insulating layer.

In the case of zinc oxide, it is sensitized with a dye with low fastness, such as rose bengal, so there are problems such as deterioration due to electrical conduction and photofading due to corona charging. Furthermore, since the zinc oxide particles are a resin dispersion system, there are problems in surface smoothness, hardness, abrasion resistance, etc. of the photosensitive layer.

On the other hand, organic photoconductive materials have advantages over inorganic ones, such as having a more flexible photosensitive layer, being easier to manufacture, and being able to obtain photoreceptors with stable electrophotographic properties at a lower cost. Many proposals have been made in recent years.

Types of photoreceptors using organic leading substances include (1
) A charge transfer complex formed by a combination of an electron-donating compound and an electron-accepting compound (e.g., U.S. Pat. No. 348
4237), (2) Organic photoconductors sensitized by adding dyes (e.g., Japanese Patent Publication No. 48-25658), (
3) Pigment dispersed in a hole- or electron-active matrix (e.g., JP-A-47-30328, JP-A-47-1)
8545), (4) functionally separated charge generation layer and charge transport layer (e.g., JP-A-49-105537),
(5) Those whose main component is a eutectic complex consisting of a dye and a resin (e.g., JP-A-47-10785); (6) those in which an organic pigment or an inorganic charge generating material is added to the charge transfer complex; (eg, Japanese Patent Laid-Open No. 49-91648).

Among these, especially (4) type photoreceptor (functionally separated type)
has been put into practical use due to its high sensitivity and the ability to select a variety of materials depending on the function. Here, the charge generation layer is usually made of polyester, a charge generation material such as an azo pigment, a phthalocyanine pigment, an indigo pigment, or a perylene pigment.
It is formed by dispersing it in a resin binder such as polycarbonate, polyvinyl butyral, or acrylic resin, and coating it on a support.

In addition, the charge transport layer is usually made of a charge transport substance such as a triphenylamine compound, a hydrazone compound, an α-phenylstilbene compound, or a pyrazoline compound, and a resin such as polyester, polysulfone, polycarbonate, polymethacrylic acid ester, or polystyrene. It is formed by dissolving it in an organic solvent, applying it, and drying it.

At this time, the stacking order of the charge generation layer and the charge transport layer can be arbitrarily determined as necessary. In addition, the undercoat layer (intermediate layer),
Overcoat layers can also be combined as necessary.

Hereinafter, an electrophotographic photoreceptor mainly using an organic material will be abbreviated as OPC.

When the base of the OPC is a flexible film such as a polyethylene terephthalate film, the photoreceptor is shaped like an endless belt, which increases the degree of freedom in mechanical design layout. Furthermore, if a portion of the endless belt is configured to form a flat surface within the copying machine, high-speed copying becomes possible by employing flash exposure.

However, in an electrophotographic photoreceptor using a flexible film as a substrate, curling occurs at the side edges, making it difficult to obtain uniform imaging over the entire flash-exposed surface. As an improvement, it is known to provide a back coating layer on the back surface of the flexible film substrate to prevent curling.

However, conventionally known flexible electrophotographic photoreceptors provided with a back coating layer (1) have a large frictional resistance of the back coating layer, so wrinkles occur during transportation, and it is difficult to wind up in a uniform shape. , its productivity drops significantly.

(2) Because the surface smoothness of the back coating layer is poor,
During winding, the material on the front side of the photoreceptor is transferred to the back side.
A so-called blocking phenomenon occurs.

There were drawbacks such as.

[Problem to be solved by the invention]

The present invention overcomes the drawbacks of the above-mentioned prior art, has excellent conveyance, shows good surface smoothness, does not generate wrinkles or blocking, provides high-quality images, and is a flexible film with excellent productivity. The purpose is to provide an electrophotographic photoreceptor.

[Means to solve the problem]

As a result of extensive studies, the present inventors have found that the above object can be achieved by incorporating silicone oil into the back coating layer, and have completed the present invention.

That is, according to the present invention, a flexible electrophotographic photoreceptor has at least a conductive layer and a single layer or a laminated photoconductive layer on a flexible film support, and further has a back coating layer on the back surface of the support. ,
There is provided a flexible electrophotographic photoreceptor characterized in that the back coating layer contains silicone oil.

The electrophotographic photoreceptor of the present invention has at least a conductive layer and a single layer or a laminated photoconductive layer on a flexible film support, and further has a back coating layer on the back side of the support. Since the back coating layer contains silicone oil, the back coating layer has excellent transportability and surface smoothness. Therefore, the electrophotographic photoreceptor of the present invention has high image quality and excellent productivity because uniform imaging can be obtained over the entire flash exposure surface, and its practical value is extremely high.

As the silicone oil used in the present invention, a compound represented by the following general formula (I) is preferably used.

The amount of silicone oil used is 10% by weight or less, preferably 1% by weight or less, based on the resin binder used in the back coating layer.

(R□, R2 represents CH3 or C5H5, m, n
represents an integer greater than or equal to 1. ) Specific examples of the silicone oil represented by the general formula (I) include the following.

Further, in the present invention, a conductive layer is provided on one surface of the support, and this conductive layer is a thin film of metal such as aluminum, nickel, chromium, titanium, etc., or a thin film of an alloy of these metals, such as nichrome, hastelloy, Inconel, stainless steel, etc. etc. are suitable.

Furthermore, metal oxide-based transparent conductive materials can also be used. It can also be achieved by applying a carbon-based paint.

The photoconductive layer may be of a single layer type or a laminated type. In the case of a laminated type, a combination of a charge generation layer and a charge transport layer, which is widely known as a functionally separated type, is preferable. The charge generation layer will be explained below.

The charge generation layer is composed of an organic charge generation material or an organic charge generation material and a binder resin.

This organic charge generating material is, for example, CI Pigment Blue 25 (Color Index CI 21180), CI Pigment Red 41 (CI 21200), CI Acid Red 52 (CI 45100), CI Basic Red 3 (CI 4521 (1), carbazole skeleton Azo pigment having (JP-A-53-9503
3), azo pigments having a distyrylbenzene skeleton (described in JP-A-53-133445), azo pigments having a triphenylamine skeleton (described in JP-A-53-133445),
132347), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-21728), azo pigments having an oxadiazole skeleton (described in JP-A-54-12742), fluorenone skeletons (described in JP-A-54-22834), an azo pigment having a bisstilbene skeleton (described in JP-A-54-22834),
-17733), azo pigments with a distyryloxadiazole skeleton (described in JP-A-54-2129), azo pigments with a distyrylcarbazole skeleton (described in JP-A-54-14967) ); for example, CI Pigment Blue 16 (CI
74100); indigo pigments such as C.I. Butt Brown 5 (CI 73410) and C.I. Butt Dye (CI 73030); Algol Scarlet B (manufactured by Bayer), Indus Thread Scarlet R (manufactured by Bayer), etc. Examples include perylene pigments, spherical dyes, and hexagonal Se powder.

These charge-generating materials are pulverized and dispersed together with a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, etc. using a ball mill, an attritor, a sand mill, or the like. At this time, for example, polyamide, polyurethane, polyester, epoxy resin, polyketone,
Resins such as polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide may be added as a binder. The charge generation layer forming liquid prepared in this manner is applied by a bead coating method, a nozzle coating method, a blade coating method, a dipping method, a spraying method, etc., and dried.
Form a charge generation layer.

Next, the charge transport layer will be explained.

The charge transport material has a main chain or a side chain containing a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, thiadiazole, triazole. Compounds having nitrogen-containing cyclic compounds such as triphenylamine compounds, hydrazone compounds
46760), α-phenylstilbene compound (Japanese Patent Application Laid-open No. 198043/1983), and the like. These charge transport materials can be used as polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Vinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenolic resin,
A charge transport layer forming liquid is prepared by dissolving a thermoplastic or thermosetting resin such as alkyred resin in a solvent such as tetrahydrofuran, dichlorohexanone, dioxane, dichloroethane, etc., and this liquid is applied by bead coating, nozzle coating, etc. A charge transport layer is formed by coating by dipping, spraying, or other methods and drying. Film thickness is 5-50
Voice is suitable, and 15 to 35 μm is preferred.

In addition, if necessary, an undercoat layer (
An intermediate layer) may also be provided. In that case, a material selected from the resins listed above can be used as a binder for the charge generation layer, and also a white pigment such as titanium oxide, an anionic fiber conductor such as sulfonic acid, an alkali metal salt of sulfonic acid, or an ammonium salt. Conductive polymers can also be added. At this time, it is preferable to select a material that does not dissolve in the solvent used in the forming liquid for the layer laminated on the undercoat layer.

Moreover, an overcoat layer can be provided as the uppermost layer if necessary.

〔Example〕

The invention is further illustrated by the following examples, which are merely illustrative, and the invention is not limited to the materials, conditions, processes, parameters, etc. recited therein.

Also, all parts and percentages are by weight unless otherwise specified.

Example 1 FIG. 1 is a sectional view of a flexible electrophotographic photoreceptor according to the present invention.

In FIG. 1, 1 is a support, 2 is a back coating layer, 3 is a conductive layer, 4 is a photoconductive layer (4a is a charge generation layer, 4
b is a charge transport layer).

A method for manufacturing the flexible electrophotographic photoreceptor according to the present invention will be explained based on FIG.

[Back coating layer forming liquid]

Polyarylate resin (manufactured by Unitika Co., Ltd.: U-401
5) Dissolve 120 parts in 720 parts of tetrahydrofuran, and add 0.0 of the compound of the following structural formula (I-a) to the solution.
24 parts were added to prepare a back coating layer forming solution.

ET) film (Nilmirror #100 manufactured by Toshisha Co., Ltd.) was coated on the support 1 and dried to form a back coating layer 2 having a film thickness of 1107 z. Next, a conductive layer 3 was formed by applying aluminum having a thickness of about 1,000 mm on the support surface opposite to the back coating layer 2 by vacuum evaporation.

In a ball mill, 13.5 parts of a compound (l) having the following structural formula, 5.4 parts of polyvinyl butyral resin (CXYHL (manufactured by UCC)) and 360 parts of tetrahydrofuran were mixed in a ball mill.
After cross-dispersion for a time, 210 parts of tetrahydrofuran and 360 parts of ethylene glycol monoethyl ether were added and cross-dispersed for 1 hour, followed by dilution with 110 parts of tetrahydrofuran and 664 parts of ethylene glycol monoethyl ether to prepare a charge generation layer forming liquid. did.

(m, n are integers of 1 or more) The back coating layer forming liquid obtained above is coated with a polyethylene terephthalate (P) having a thickness of 100 mm using a doctor blade and dried to form a layer of approximately 0. A charge generation layer 4a having a thickness of .5 μm was provided.

Furthermore, 90 parts of a compound (m) having the following structural formula, 10 parts of polycarbonate resin (Panlite 11300 manufactured by Teijin)
0 part was dissolved in 790 parts of tetrahydrofuran, and 0.2 part of silicone oil (KF-50 manufactured by Shin-Etsu Chemical Co., Ltd.) (1% tetrahydrofuran solution) was added to prepare a charge transport layer forming liquid.

3 Apply this liquid onto the charge generation layer 4a using a doctor blade and dry it to form a charge transport layer 4b of approximately 27R.
An electrophotographic photoreceptor of the present invention was prepared.

Comparative Example 1 A flexible electrophotographic photoreceptor of Comparative Example 1 was prepared in the same manner as in Example 1, except that the back coachine layer forming liquid was replaced with the one shown below.

[Back coating layer forming liquid]

Polyarylate resin (manufactured by Unitika Co., Ltd.; U-4015
) 120 parts dissolved in 720 parts of tetrahydrofuran.

Regarding the flexible electrophotographic photoreceptors of Example 1 and Comparative Example 1 obtained as described above, (1) friction coefficient and gloss of the back coating layer, (2) occurrence of wrinkles and blocking on the photoreceptor, and (3) ) Three types of evaluations of the copied images were conducted. The results are shown in Table-1.

The measurement method was as follows.

[Friction coefficient of back coating layer]

The measurement was carried out using a Toyo Seiki Co., Ltd. friction angle measuring machine, and a Toshi Co., Ltd. Lumirror $10O3 as the friction facing member.

[Glossiness of back coating layer]

The 20 degree specular gloss measurement method (Gs (20 degrees)) was carried out using VGS-10 manufactured by Nippon Heavy Industries.

[Occurrence of Wrinkles and Blocking in Photoreceptor] The presence or absence of film wrinkles and blocking in the manufacturing process of the photoreceptors of Example 1 and Comparative Example 1 was visually evaluated.

[Evaluation of copied images]

The photoconductors of Example 1 and Comparative Example 1 were used in a copying machine (Ricoh FT
-9.100), an image was produced, and the resulting copied image was visually evaluated.

Table 1 [Effects] The electrophotographic photoreceptor of the present invention has at least a conductive layer and a single layer or a laminated photoconductive layer on a flexible film support, and further includes a back coating on the back surface of the support. In a flexible electrophotographic photoreceptor having a layer, the back coating layer contains silicone oil, so that the back coating layer has excellent transportability and surface smoothness. Therefore, since the electrophotographic photoreceptor of the present invention can form a uniform image over the entire flash exposure surface, it has high image quality and excellent productivity, and has extremely high practical value.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a flexible electrophotographic photoreceptor according to the present invention. Patent applicant Rico Co., Ltd.

Claims (2)

[Claims] (1) A flexible electrophotographic photoreceptor having at least a conductive layer and a single layer or a laminated photoconductive layer on a flexible film support, and further having a back coating layer on the back surface of the support, the back coating layer A flexible electrophotographic photoreceptor characterized by containing silicone oil. (2) The flexible electrophotographic photoreceptor according to claim (1), wherein the silicone oil is a compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (R_1 and R_2 represent CH_3 or C_6H_5, and m and n represent integers of 1 or more.)