JPS59155844A - Laminated type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body high in sensitivity and good in electrostatic charge transfer efficiency by forming an acceptor type org. substance layer and a layer contg. a donor type low mol.wt. substance dispersed into a resin on a conductive substrate, and forming a thin charge transfer complex layer on the interface between both layers. CONSTITUTION:An org. substance layer 2 contg. an acceptor type low mol.wt. substance, such as 2,4,7-trinitro-9-fluorene or 1,3,5-tricyanobenzene, dispersed into a binder resin, or made of an acceptor type polymer, such as polyvinyl butyral or maleic acid resin, is formed on a conductive substrate 1. Next, a donor layer 4 contg. a donor type low mol.wt. substance, such as pyrene, p-diethylamino-benzaldehyde-N-alpha-naphthyl-N-phenylhydrazone, moleclarly dispersed into a resin is formed on the layer 2. As a result, on the interface between the layers 2, 4 a thin charge transfer complex layer 3 is generated. A negatively chargeable photosensitive body is thus obtained. A positively chargeable photosensitive body is obtained by reversing the layers 2, 4. The obtained photosensitive body is enhanced in sensitivity and reduced in fluctuation of potentials of the light and dark parts by forming the layer 3 even when light illumination and charging are repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that a layer of an acceptor organic substance and a layer of a donor low-molecular substance molecularly dispersed in a resin are laminated on a conductive support. The present invention relates to a laminated electrophotographic photoreceptor.

BACKGROUND ART Conventionally, electrophotographic photoreceptors of the type in which a charge generation layer and a charge transport layer are laminated on a conductive support are known.

However, with this glazed laminated photoreceptor, sufficient sensitivity has not yet been obtained, and the photoreceptor is exposed to strong light.
Immediately after exposure, exposure was carried out, which had the disadvantage that the bright and dark potentials fluctuated greatly.

OBJECTS OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks.

Structure and Effects of the Invention The photoreceptor of the present invention has a layer of an acceptor organic substance and a layer of a low-molecular acceptor substance dispersed in a resin on a conductive support, so that a charge is generated at the interface between the two layers. This method is characterized by forming a thin layer of a mobile complex and using it as a charge generation layer. In this specification, the term "acceptor organic substance" refers to either an acceptor low molecular substance, an acceptor low molecular substance molecularly dispersed in a polymer matrix, or an acceptor polymer substance.

The photosensitive layer is functionally separated into a charge transport layer and a charge transport layer.
The reason why the density of the layered photoreceptor does not improve Furthermore, it is thought that the injection of carriers from the charge generation layer to the charge transport layer is not occurring efficiently.At the same time, the aforementioned inefficiency of carrier movement may cause the photoreceptor to be exposed immediately after being exposed to strong light. When charging and exposure are repeated, this has an important influence on the fluctuations of the bright and dark potentials.The present inventors investigated the interaction between the two substances at the interface between the acceptor substance layer and donor substance layer By forming a thin layer of a charge transfer complex and forming this thin layer f charge generation layer, holes and electrons generated by exposure are efficiently prevented from being trapped within this thin layer, and are transferred to a donor substance layer, It was also discovered that since the entire acceptor substance layer moves, the sensitivity is improved, and at the same time, it is possible to reduce fluctuations in the bright and dark potentials when charging and exposing the photoreceptor repeatedly immediately after intense exposure [ 7.

As used herein, the term "charge transfer complex" refers to an electron donor D71.
The stabilizing energy is obtained by some movement of electrons from D to A, and the 12IJ complex is formed after being charged. Whether or not it is fc can be easily confirmed by the force λ and force where a spectroscopic charge transfer absorption band is observed.Generally speaking, in terms of material selection, the ionization potential of D is small, and the electron affinity of A is small. It can be said that it is better to find a compound with a large EA and to create a state with good molecular and solid structure structure. 1) is a system in which a donor low-molecular substance is molecularly dispersed in a resin. ,A
refers to any one of an acceptor polymeric substance, an acceptor low-molecular substance molecularly dispersed in a polymeric compound, and an acceptor polymeric substance.

The materials used to prepare the laminated electrophotographic photoreceptor of the present invention include, for example, 1,3,5-) lycyanobenzene, m-dinitroben7, 1, 2,4.5-tetracyanobenzene, tetrachlorophthalic anhydride, maleic anhydride, 2,4.6
-) IJ Nitrotoluene, 1.3.5-) IJ
Nitrobenzene, p-benzoquinone, pyromellitic anhydride, chloro-p-benzoquinone, 1,2-dicarboxy-1,2-dicia/': r-fV7.2. Riichijikuro p! Benzoquinone, 2,5-dichloro-p-''nzoquinone, 2,6-dichloro-p-benzoquinone, 2,4
．． 7-dolinitro 9-fluorenone, trichloro-p
-benzoquinone, p-iodoanil, p-chloranil,
p-chloranil, ○-chloranil, 0-chloranil, tetracyano-p-benzoquinone, tetracyano-p-
Quinodinothane, 2,3-dicyano-p-benzoquinone,
2,6-dinitro-p-benzoquino/, tetracyanoethylene, 2,3-cyclo0-5.6-dicyazup-4
Examples include quinone and the like. Furthermore, these acceptor-based low-molecular substances may be used by being molecularly dispersed in a polymer matrix. , acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, polycarbonate, polyurethane, or two or more of the seven repeating units of these resins. Examples of the copolymer resins include styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, and the like.

Furthermore, examples of acceptor polymer substances include polyvinyl butyral, maleic resin, ketone resin, cellulose ester, etc., which can be used alone or in combination of two or more. may be done.

- 1,000, toner-like low molecular weight substances include pyrene, N-ethylcarbazole, 1. IM-Isopropylcarbazole, N-Methyl-blocked-phenylhydrazino-3-noteridene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N
, N-diphenylhydrazino-3-methylidene-10-
Ethylphenothiazine, N,N-diphenylhydrazino-3-notylidene-10-ethylphenoxazine, p-
Diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N
-α-Naphthyl-N-phenylhydrazone, p-pyrrolidinylbenzaldehyde-N,N-diphenylhydrazone, 1.3.3-trimethylindolenine-ω-aldehyde-N,N-diphenylhydrazone, p-diethylbenzaldehyde- 6,-methylbenzthiazolinone-2
- Hydrazones such as hydrazone, 2,5-bis(p-'
, ;ethylaminophenyl)-1,3,4-oxadiazole, 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl(21]-]5 - (p-diethylaminosteryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2,)-3-(T
) -diethylaminosteryl) -5-(p-diethylaminophenyl]virazo 9;/, 1-C6-1 toxicpyridyl (2) ] -3-(p-diethylaminosteryl) -5-(T)-diethylamino phenyl)pyrazoline, 1-[pyridyl(3)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[levidyl(2.:]-3-(
one diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl (2)
] -3-(p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2) ]' -3-(υ-methyl-p-diethylaminostyryl)-5-( TI-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p
-diethylaminostyryl)-4-methyl-5-(p-
diethylaminophenyl)pyrazoline, 1-phenyl-
Pyrazolines such as 3-(α-benzyl-TT-diethylaminostyryl)-5-('p-diethylaminoenyl)pyrazoline and spiropyrazoline, 2-(p-diethylaminostyryl]-6-ethylaminobenzoxazole, 2- (p-diethylaminophenyl)-4
-(p-dimethylaminophenyl)-5-(2-10lophenyl) oxazole compounds such as oxazole,
Thiazole compounds such as 2-(p-diethylaminostyryl)-6-ethylaminobenzothiazole, bis(
Triarylmethane compounds such as 4-diethylamino-2-methylphenyl)-phenylmethane-11,1-bis(4-N,N-diethylamino-2-methylphenyl)
Hebutane, 1,1,2,2-tetrakis(4-N,N-
Materials selected from polyaryl alkanes such as dimethylamine-2-methylphenyl)ethane, triphenylamine, and the like can be used.

Moreover, these donor-like low-molecular substances can be used alone or in combination of two or more.

Further, examples of resins that can be used for molecularly dispersing the donor low-molecular substance mentioned above include acrylic resin polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene, copolymer, polyvinyl butyral, polyvinyl Insulating resins such as formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or polystyrene, polymethylstyrene, polydinotylaminostyrene, polyvinylcarbazole, polycarbasylethyl vinyl ether, poly-2-vinylpyridine, poly-4 - Organic photoconductive polymers such as vinylpyridine, poly-2-methyl-5-vinylpyridine, polyna 7-tylmethyl daltamate, polyhinylnaphthalene, polyvinylanthracene, polyvinylpyrene, polyvinylphenyanthracene, polyacenaphthalene, etc. be able to.

FIG. 1 of the accompanying drawings shows a sectional view of a laminated photoreceptor of the present invention coated on the surface of a conductive layer 1. As shown in FIG. In this example, a dove 2 made of an acceptor organic substance is electrically connected to a layer 4 made of a donor polymer substance, and at an interface 3 between these layers,
A charge transfer complex is formed. At this time, by performing exposure in the presence of negative corona charging, of the charge carriers generated at the interface 6, holes are efficiently injected into Ni4 and electrons are injected into the layer 2, respectively.

FIG. 2 shows another example of the laminated photoreceptor of the present invention. In this example, compared to FIG. 1, layers 4 and 2 are stacked in reverse order, and positive corona charging is used.

A photosensitive layer having such a laminated structure of one donor layer and one acceptor layer is provided on a substrate having a conductive layer.

The substrate with a conductive layer may be one that itself is conductive, such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, metal, chromium, titanium, nickel, indium, gold, or platinum. (-I)a Plastics (e.g., polyethylene, polypropylene, , polyvinyl chloride, polyethylene terentate, acrylic resin, polyfluoroethylene, etc., conductive particles (e.g. carbon black, silver particles, etc.) are coated on a plastic with a suitable binder, and the conductive particles are coated on a plastic. A substrate impregnated with plastic or paper, a plastic containing a conductive polymer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. The subbing layer is casein,
Polyvinyl chillol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide, etc.

The thickness of the undercoat layer is suitably 0.1 to 5 microns, preferably 0.5 to 3 microns.

Examples of organic solvents used to form the undercoat layer, donor layer, acceptor layer, etc. include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, N, Amides such as N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, and esters such as methyl acetate and vinegar Wl/:r-f. - Aliphatics such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethylene)
) Logenated hydrocarbons or aromatics such as benzene, toluene, xylene, refloin, monochlorobenzene, dichlorobenzene, and the like. Naturally, the organic solvent used to form each layer varies depending on the type of substance used. Furthermore, when forming an undercoat layer, the solvent used for the donor layer or acceptor layer may be used for the undercoat layer. It is preferable to select from those that do not dissolve.

What is particularly ingenious about the laminated photoreceptor of the present invention is the method of forming as thin a layer of charge transfer complex as possible at the interface between the donor and acceptor layers. In other words, by efficiently forming a charge-transfer complex in the auxiliary layer at the interface between the donor layer and the acceptor layer, the sensitivity is increased, and at the same time, the potential changes when repeatedly charged and fogged immediately after irradiating the photoreceptor with strong light are reduced. This is a product that has succeeded in improving the characteristics of

The specific method is to first form a first layer coating of donor or acceptor on the conductive layer using the coating method described below and dry it, then as a second layer, one layer of iodine and one layer of donor. If so, the acceptor substance is dissolved in a solvent, and if the first layer is a single acceptor layer, the donor substance is dissolved in a solvent and laminated. However, it is necessary to select a solvent for the second layer that also dissolves the substance used for the first layer. Then, the moment the second layer is applied, a color change can be seen at the interface between the first and second layers, and a thin layer of charge transfer complex is immediately formed. In addition, in order to confirm that a charge transfer complex is formed due to the interaction between the donor substance and the acceptor organic substance as described above, a coating film is created using a coating liquid containing a mixture of both substances.
The absorption can be determined by confirming that a characteristic strong absorption based on charge transfer appears in the visible light region of the vector. At this time, depending on the selection of the donor substance and acceptor organic substance, a sufficiently strong charge transfer absorption band may not appear in the visible light region, and the sensitivity when stacking such substances is naturally not good. Ta.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30°C to 200°C for 5 minutes to 2
It can be carried out stationary or under blown air for a period of time within a range of hours.

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 also be widely used in electrophotographic application fields such as electrophotographic plate making systems.

According to the present invention, a highly sensitive electrophotographic photoreceptor can be provided, and the photoreceptor can be exposed to rape light. □It has the advantage that fluctuations in the bright area potential and dark area potential when repeated charging and exposure are performed immediately after exposure to light can be reduced.

Hereinafter, the present invention will be explained according to examples.

Example 1: 30 CCK of total tetrahydrofuran was dissolved. This coating solution was applied to the all-aluminum sheet soil using a Mayer parser so that the dry film thickness was 8 microns to form a single layer of acceptor.

Next, a hydrazone of the following structural formula (1) and a styrene-acrylic resin as a binder (product name: Nippon Steel Chemical Co., Ltd.:
M8-200) mixed in a 1:1 weight ratio with a monochlorobenzene 20i quantity solution 'f was coated on the charge generation layer using a Mayer Parr so that the dry film thickness was 12 microns, and a single layer of donor was formed. A photosensitive layer having a 2R structure was prepared and designated as Sample 1.

On the other hand, as a comparative sample, a charge generation layer was placed on a conductive support.
A functionally separated photoreceptor having charge transfer layers laminated in this order was prepared as follows.

That is, the following disazo pigment (2
) and add cyclohexanone 18.1F to it.
I added Glass Peas 20 tri and performed dispersion sound for 4 hours with Red Devil fc.

To this dispersion was added 4.42 mol of a 91 M solution of polyvinyl butyral (BIVI-2 manufactured by Tasekisui Chemical Co., Ltd.) as a binder at a weight ratio of noterethyl ketone:cyclohexanone = 1:1, and for another 2 hours. Dispersed by Red Devil.

This dispersion was applied onto an aluminum sheet using a Mayer bar to form a charge generation layer to a dry film thickness of 0.2 microns.

Next, the hydrazone of the structural formula (1) and the styrene-acrylic resin (trade name Nippon Steel Chemical) as a binder are added.
A monochlorobenzene 203 binder solution prepared by mixing 1:1 weight ratio of 1:1 weight ratio with Me-200) was applied onto the charge generation layer using a Mayer Parr so that the dry film thickness was 12 microns to form a charge transport layer. Fully formed.

Comparative sample 1 was prepared in this manner.

The electrophotographic photoreceptor thus prepared was dynamically corona charged using Kawaguchi Electric Co., Ltd.'s Seiden Copy Paper Tester Model SP-428, held in a dark place for 1 second, and then charged for 4 seconds at an illuminance of 5 lux. It was exposed to light and its charging characteristics were investigated.

As for the charging characteristics, the surface potential and the exposure level (Es) required to attenuate the potential (Vl) when dark decayed for 1 second to S were measured.

Furthermore, as a way to simply express the degree of variation in the bright area potential and dark area potential when used repeatedly, a sample that has been subjected to the above measurement once was irradiated with a 600 lux fluorescent lamp for 6 minutes.
After that, the sample was left in a dark place for 1 minute and then charged and exposed again, and the potential difference ΔV1 between vl and the first time is representative. The larger the value of ΔV1, the greater the variation in the bright and dark potentials upon repeated use.

Next, the measurement results for the above photoreceptor will be shown.

From the above results, it can be seen that Sample 1, which has the layer structure of conductive support, one acceptor layer, and one donor layer, has high sensitivity and small potential fluctuations when exposed to strong electric light of one digit. On the other hand, it can be seen that the characteristics of Comparative Sample 1Fi, which has a layer structure of a conductive support, a charge generation layer, and a charge transport layer, are not good. This result indicates that many traps exist in the charge generation layer, and carriers generated by light irradiation cannot move efficiently.

Example 2 Aluminum sheet was placed on a hot plate for 180 min.
2.4.7- in a crystalline state on an aluminum sheet by heating to ℃.
) IJ nitro-9-fluorenone 12 was melted in 9 baths. Immediately after that, the coating was applied to a constant film thickness using a Meyer Parr heated to 180°C, and then removed from the hot plate and left to cool rapidly at room temperature.
An amorphous state with a film thickness of microns was obtained. Furthermore, the structural formula (1
) was laminated to form Sample 2, and the charging characteristics were investigated, and the following results were obtained.

Example 6 53cc glass bottle made of polyamide (CM manufactured by Menjin Meitoshi ■)
-8000/Teikoku Kagaku ■ Trezine! //1 weight ratio]
A 2M methanol solution was applied onto an aluminum sheet using a Mayer bar so that the dry film thickness was 0.5 microns to form an undercoat layer.

Next, hydrazone of structural formula (3) and styrene-acrylic resin as a binder (trade name: MS-200 manufactured by Nippon Steel Chemical Co., Ltd.) were combined into 1
．． Monochloroben 4 F20 mixed in a weight ratio of 1
A single layer of the donor layer was formed by applying the % heavy weight solution onto the previous subbing layer using a Mayer bar to a dry film thickness of 12 microns.

Next, 3 tons of maleic anhydride was dissolved in 30 cc of tetrahydrofuran. This coating solution was applied onto the polystyrene layer using a Mayer Parr so that the dry film thickness was 8 microns. 6 created as above
A laminated type photoreceptor was designated as Sample 3, and its charging characteristics were examined in the same manner as in Example 1. However, the charging polarity is set to Q]. The results are shown in the table below.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of an example of the electrophotographic photoreceptor of the present invention. 1. Conductive substrate 2 Acceptor layer 6. Charge transfer complex layer 4... Donna layer Patent applicant Canon Co., Ltd. Agent Patent attorney Yu Kano

Claims (1)

[Claims] (1) By providing a layer consisting of an acceptor organic substance and a layer in which a donor low-molecular substance is molecularly dispersed in a resin on a conductive support, a thin layer of a charge transfer complex is formed at the interface between the two layers. S. A layered electrophotographic photoreceptor.