JPS59155845A - Laminated type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body small in fluctuation of potential of the light and dark parts and high in sensitivity by forming an acceptor type org. substance layer and a donor type polymer substance layer on a conductive substrate, and forming a thin charge transfer complex layer on the interface between both layers. CONSTITUTION:An acceptor type org. substance layer 2 contg. an acceptor type low mol.wt. substance, such as 1,3,5-tricyanobenzene or m-dinitrobenzene, disersed into a resin for a blending polymer, such as polyacrylate or polyamide, or dispersed into an acceptor type polymer, such as polyvinyl butyral or maleic acid resin, is formed on a conductive substrate 1. Next, a layer 4 made of a donor type polymer, such as polystyrene or polycarbazole, is formed on the layer 2. As a result, on the interface between the layers 2, 4, a thin layer 3 of a charge transfer complex is generated. A negatively chargeable photosensitive body is thus obtained. A positively chargeable photosensitive body is obtained by reversely laminating 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 exposure and charging are repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a multilayer electrophotographic photosensitive material, characterized in that a layer of an acceptor organic substance and a layer of a donor polymer substance are laminated on a conductive support. Regarding the body.

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 photoconductor, sufficient sensitivity has not yet been obtained, and when the photoconductor is irradiated with strong twisting light and immediately after 'fc', repeated 'jjj□ electricity and lightning are applied. had the disadvantage that the bright and dark potentials fluctuated widely.

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 made of an acceptor organic substance 1.- and a donor polymeric substance on a t+' support member, thereby creating a charge at the interface between the two layers. It is characterized in that it forms a thin layer of a mobile complex and is used as a molecule.

In addition, in this specification, "J substance with acceptor property" refers to any of acceptor substance, low molecular substance, acceptor substance, molecularly dispersed in a molecular matrix, and acceptor bacterial molecular substance. Kan-say.

Photosensitive) The reason why the sensitivity of the laminated photoreceptor in which 1- is separated from the charge generation layer and the charge 4'+i:I is not improved due to the charge separation is due to trapping of carriers generated in the charge generation material. , and the holes and electrons generated by light irradiation cannot move efficiently.
Possible reasons include that the injection of carriers from the charge generation layer to the charge transport 1ψ is not occurring efficiently. At the same time, the above-mentioned inefficiency of carrier movement has a significant effect on fluctuations in bright area potential and dark area potential when charging and exposure are repeatedly performed immediately after irradiating the photoreceptor with strongly twisted light. The present inventors formed a thin layer of a charge transfer complex at the interface between the acceptor substance layer and the donor substance layer through the interaction of the two substances, and by using this thin layer as a charge generation layer, the present invention realized that light exposure is possible. The generated holes and electrons are not trapped within this thin layer and efficiently move through the donor material layer and the acceptor material layer, respectively, resulting in high sensitivity and at the same time, the photoreceptor can be used immediately after being irradiated with strongly twisted light. We have discovered that it is possible to reduce fluctuations in bright and dark potentials when repeatedly charged and exposed to light.

As used herein, the term "charge transfer complex" refers to an electron donor (L+)
Stabilizing energy is obtained by some movement of electrons to D/Noshi A in the state-like molecular button DA consisting of an electron acceptor (AI), and whether or not a charge transfer complex is formed is determined by This can be easily confirmed by whether or not spectroscopic spectroscopic mass transfer absorption fireflies are observed.Generally, in terms of material selection, the ionization potential of D is small, and the ionization potential of A is small.
It can be said that it is better to find a compound with a large electron affinity EA, and also to create a good molecular and solid state (D is do). A is a low molecular weight acceptor substance, a low molecular weight acceptor substance molecularly dispersed in a polymer matrix, a 2-layer polymeric substance, or an acceptor polymer substance.

The materials used to create the laminated electrophotographic photoreceptor of the present invention include, for example, the acceptor low molecular weight substances.
L3,5-t+)cyanobenzene, m-dinitrobenzene, 1.2,4.5-tetrasia,/benzene, tetrachlorophthalic anhydride, maleic anhydride fN, 2,4.
6-) IJ nitrotoluene, 1.3,5-trinitrobenzene, p-benzoquinone, pyromellitic anhydride, chloro-p-benzoquinone, 1,2-dicarboxy-1,2-dicyanoethylene, 2,3- dichloro-p-
Benzoquinone, 2,5-dichloro-p-benzoquinone,
2,6-dichloro-p-benzoquinone, 2,4.7-
)Rho9-fluorenone, trichloro-p-benzoquinone, p-iodoanil, p-bromal, p-
Chloranil, o-chloranil, lebromanil, tetracyano-p-benzoquinone, tetracyano-η-quinodimethane, 2,3-dicyano-p-benzoquinone, 2,6
-Sinitro 1]-benzoquinone, tetracyanoethylene, 2,6-dichloro-5,6-dicyano-p-benzoquinone, and the like. Furthermore, these acceptor-based low-molecular-weight substances may be used as molecularly dispersed medium molecules of IJ-Lux, and the but/end polymers used in this case include, for example, polyarylate resins, polysulfone resins, Polyamide resin, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride%↑fat, be
Dinyl acid resin Phenol resin, epoxy resin, polyester resin, alkyd resin, polycarbonate, polyurethane or two of the repeating units of these resins
Copolymer resins containing more than one such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer,
It can melt styrene-maleic acid copolymers, etc., and it can also melt acceptor 1q-polymer substances such as polyvinyl butyral, maleic acid resin, ketone resin, cellulose ester, etc.! The glaze may be used alone or two or more glazes may be used in combination.

On the other hand, donor sieve molecules include, for example, polystyrene, polymenal styrene, polydimethylaminostyrene, polyhinyl hasol, polycarbasylethyl vinyl ether, poly-2-vinylpyridine, poly-4-vinylbi, lysine, and Examples include -2-methyl-5-vinylhyridine, polynaphthylmethylglutamate, polyvinylnaphthalene, polyvinylanthracene, polyvinylpyrene, polyhinylphenylanthracene, and polyacenaphthalene.

Figure 1 of the accompanying drawings shows a cross-sectional view of a laminated photoreceptor of the present invention coated on the surface of a conductive layer 1. In this example, a layer 2 made of an acceptor organic substance is electrically connected to a layer 4 made of a donor polymeric substance, and a charge transfer complex is formed at an interface 5 between these layers. At this time, by performing exposure and light in the presence of negative corona charge, holes and electrons of the charge carriers generated at the interface 6 are efficiently injected into the layer 4 and the layer 2, respectively.

FIG. 2 shows another example of the laminated photoreceptor of the present invention. In this example, compared to 1l-1' in FIG. 1, layer 4 and layer 2 are stacked in reverse order, and a positive corona zone 1M,'T is used.

A photosensitive layer having such a laminated structure of one donor layer and one acceptor layer is provided on a substrate having 24 electrode layers.

Examples of substrates having a conductive layer include those whose substrate itself is conductive, such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, y-/L/, indium, and gold. In addition, plastics (for example, polyethylene, polypropylene, polyethylene, vinyl chloride, polyethylene terephthalate, acrylic resin; A substrate impregnated with paper or a plastic containing a conductive polymer can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. Subtraction 1* iJ: ,
casein, polyvinyl alcohol, nitrocellulose,
Ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane,
-C can be formed with ceratin, 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 impropatol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; N,N-dimethylformamide, N,N-
Amides such as dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, chloroform, methylene chloride, dichloroethylene, tetrachloride Examples include carbon, Ω-aliphatic halogenated hydrocarbons such as trichloroethylene, and aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, and dichlorobenzene.

Naturally, the organic solvent used to form each layer varies depending on the type of substance used, and if all layers of the undercoat layer are used, the solvent used for the donor layer or acceptor layer will dissolve the undercoat layer. It is preferable to choose from those that do not.

In the laminated photoreceptor of the present invention, a particularly original method (i-) is a method of forming as thin a layer of charge transfer complex as possible at the interface between the donor layer, the acceptor layer, and the donor layer. By efficiently forming a thin layer of charge-transfer complex at the interface, we succeeded in increasing sensitivity and at the same time improving the characteristics of potential changes when repeatedly charging and exposing the photoreceptor immediately after full irradiation with intense light. It is something.

The specific method is to first form a first layer of donor or acceptor coating on the conductive layer using the following coating method, dry it, and then apply a second layer of donor or acceptor layer if the first layer is a single donor layer. If the first layer is an acceptor layer, the donor material is dissolved in a total 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 observed at the interface between the first layer and the second layer, and a thin layer of the charge transfer complex is immediately formed. It is confirmed that a charge transfer complex is formed by the interaction between the donor substance and the acceptor organic substance as described above. For this purpose, it is sufficient to create a coating film using a coating liquid that is a mixture of both substances, and to confirm that characteristic strong absorption based on charge transfer appears in the visible light region of the absorption spectrum. At this time, depending on the selection of the donor polymer material and the acceptor organic material, a sufficiently strong charge transfer absorption band may not appear in the visible light region, and the sensitivity when such materials are stacked is amazing. However, it wasn't good.

Coating can be carried out using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a beat coating method, a coating method, a Meyer coating method, a blade coating method, a roller coating method, a curtain coating method, or the like. A preferred drying method is to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30℃ to 200℃ for 5 minutes or more
For a period of time in the range of 2 hours, it can be washed in a still place or under blown air.

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, it is possible to provide a highly sensitive electrophotographic photoreceptor, and the change in bright area potential and dark area potential when repeatedly charging and exposing the photoreceptor immediately after irradiating the photoreceptor with intensely twisted light It has the advantage that it can be made small.

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

Example 1 Non was dissolved in 33 cc of tetrahydrofuran. This coating solution was applied onto an aluminum sheet using a Mayer coating to a dry film thickness of 8 microns to form a single acceptor layer.

Next, dissolve it in tetrahydrofuran 300C (No. 10) to make a coating liquid, and apply it on top of the previous acceptor layer using a Mayer bar to a dry film thickness of 8 microns to form a two-layer structure. An electrophotographic photoreceptor having a photosensitive layer was prepared and designated as Sample 1.

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

That is, the following disazo pigment (i
K4.1y was taken, and cyclohexanone 1a17, Glass Peas 20+r, and J'e were added thereto and dispersed for 4 hours using Red Devil.

To this dispersion, 9.1 g of a solution of polyvinyl butyral (BM-2, manufactured by Tasekisui Chemical Co., Ltd.) as a binder in a weight ratio of methyl ethyl ketone and cyclohexanone to 11 was added as a binder.
．． 4? In addition, the mixture was further dispersed with Red Devil for 2 hours. 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, a hydrazone of the following structural formula (2) and a styrene-acrylic resin as a binder (trade name: Nippon Steel Chemical Co., Ltd. M
A 20 M mass % solution of monochlorobenzene prepared by mixing S-200) with a ratio of 1:1 was coated on the charge generating j- with a Mayer bar so that the dry Nu amount was 12 microns. A transport layer was formed.

Comparative sample 1 was prepared in this way.

The electrophotographic photoreceptor produced in this manner was tested using electrostatic copying paper test equipment MO+10', 1.8'l''-4 manufactured by Kawaguchi Electric Co., Ltd.
Corona 11bu't4 using dynamic method using 28
After holding the sample in a dark place for 1 second, it was exposed to light for 4 seconds at 11 degrees (5 degrees) to examine the charging characteristics.

The charging characteristics are as follows: surface level and light intensity required to attenuate to 1 second (Vl) f%.
EH,) was measured.

In addition, 1p when used with edge return and 1lii
As a method of expressing the degree of variation in the location on the opposite bank, a sample subjected to the above-mentioned I; Irradiated with fluorescent lamps u and x for 6 minutes, then left in a dark place for 1 minute. When exposed to charge again, the potential difference from the first time of Vl △■
It shall be represented by 1. The larger the value of △V1,
When used repeatedly, the bright area potential and dark area potential fluctuate greatly.

Next, the results for the above photoconductor will be shown.

From the above results, it can be seen that Sample 1, which has a layered structure of conductive support, acceptor, Ri, and one donor, has high sensitivity and small potential fluctuations when intense brain light is applied. On the other hand, it can be seen that Comparative Sample 1, which has a layer structure of two electrically conductive supports, one charge generation layer, and one charge transport core, has poor characteristics. This result is
There are many traps in the charge generation layer, indicating that the gear produced 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 ℃.
) Rinitro 9-fluorenone 12 was taken and melted. Immediately thereafter, it was coated with a wire parr heated to 180° C. to a film thickness of constant τ, and then removed from the hot plate and left to cool rapidly at room temperature to obtain a transparent amorphous film with a thickness of 1 μm. Furthermore, Example 1
Sample 2 was obtained by laminating poly-N-vinylcarbazole with a film thickness of 8 microns in the same manner as above, and the charging characteristics were investigated, and the following results were obtained.

Example 6 5Qcc glass bottle made of polyamide (manufactured in multiple bundles)
A 2% by weight methanol solution of -8000/Teikoku Kagaku (trade name) manufactured by Teikoku Kagaku ■'AM) was coated on an aluminum sheet with a Nimeyer paper to a dry film thickness of 0.5 microns to form an undercoat layer.

Next, polystyrene (product name: Sanen Monzanto 62 ■ Dialex H11'55) Total monochlorobenzene 27? (It was dissolved to 10% by weight to form a coating solution, and coated onto the previous subbing layer using a Mayer bar to a dry film thickness of 8 microns.

Next, maleic anhydride 37 was dissolved in 30 cc of tetrahydrofuran. Apply this coating solution on top of the polystyrene layer to a dry film thickness of 8.
It was coated to a micron thickness. The six-layer laminated photoreceptor produced as described above was used as a sample F43, and its charging characteristics were examined in the same manner as in Example 1. However, the charging property at this time is ■
And so. The results are shown in the table below.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are cross-sectional views of an example of the electrophotographic photoreceptor of the present invention. 1 Conductive substrate 2...Acceptor y/J 6...', cargo transfer complex layer 4...Donna further peeking/J■ - Applicant Canon Co., Ltd. Agent Patent attorney Yu Kano

Claims (1)

[Claims] (1) A thin layer of a charge transfer complex is formed at the interface between the two layers by providing a layer made of an acceptor organic substance and a layer made of a donor polymer substance on a tetraelectric support. Laminated electrophotographic photoreceptor.