JPS62175761A - Electrophotographic method - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having a very high sensitivity and a good stability and a good sensitivity also under a positive electrostatic charge by dispersing a small amount of specific bisazo compd. particles in a hydrazone type binder having an electrostatic charge transfer function. CONSTITUTION:The electrophotographic sensitive body provides the sensitive layer dispersed 1-20wt% of the bisazo compd. particles in the binder contg. the hydrazone compd. on a conductive substrate body. The prescribed body is electrostatically charged by a positive corona discharge, followed by image wisely-exposing, developing and transferring it. The obtd. electrophotographic sensitive body has the excellent sensitivity also under the positive electrostatic charge, and has the excellent potential stability during repeated use, and has no fatigue such as an optical memory and has a very stable characteristics.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to an electrophotographic method.

Specifically, the present invention relates to an electrophotographic method in which a dispersion type electrophotographic photoreceptor containing a specific organic base conductive material/Jt is used with high sensitivity and positive charging with excellent safety.

<Prior Art> Conventionally, inorganic thread photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used in the sensory layer of photosensitive elements.

In recent years, research has become active in using organic conductive materials such as polyvinyl carbazole in photosensitive layers. A laminated type photoreceptor consisting of two layers, a charge generation layer and a charge transfer layer 14, which have separate functions for transferring charges, has been devised and has become the mainstream of research.

Laminated photoreceptors have been put into practical use by combining organic compounds each having a highly efficient charge generation function and a charge transfer function to obtain a highly sensitive photoreceptor. Organic photoreceptors have become the mainstream photoreceptor because there is a wide range of materials to choose from, and a highly safe photoreceptor can be obtained depending on the material selection, and the coating productivity is high and it is relatively advantageous in terms of cost. It has great potential and is being actively developed.

<Problems to be Solved by the Invention> However, conventional multilayer electrophotographic photoreceptors have a charge transfer layer on top of the charge generation layer, and the charge transfer layer usually does not transfer holes. Because it has no conductivity, it is sensitive only when negatively charged and cannot be used below the positive band.

On the other hand, in electrophotographic methods, the photoreceptor is normally charged by corona discharge, but negative corona discharge is more difficult to uniformly discharge in one direction than positive corona discharge. difficult to obtain,
Furthermore, regarding the generation of ozone and nitrogen oxides, which can cause photoreceptor deterioration, negative corona group '4 generates much more. Since the thread was positively charged, the subsequent developer used in this thread cannot be used, and there are many disadvantages such as the conventional technology cannot be used in other peripheral processes in the case of negative charge. Therefore, the emergence of an organic photoreceptor that can be used with positive charging has been required.

Polyvinyl carbazole is an organic photoreceptor that has sensitivity under positive charge and can be used as an electrophotographic photoreceptor. ,4. Charge transfer complexes of cootrinitrofluorenone and J-type photoreceptors using electron transfer media are known, but their safety is questionable and their electrical properties such as sensitivity are insufficient. There were other problems. Even if it is a hole transfer type laminated photoreceptor, does it have a layer structure? On the other hand, there are photoreceptors in which a charge generation layer is provided on the IE charge transfer layer, and photoreceptors in which particles with a charge generation function are dispersed in a charge transfer medium, but they suffer from problems such as sensitivity and fatigue. In this respect, a photoreceptor that can be positively charged and used has not yet been obtained.

<Problems and Means for Solving the Problems> For the above reasons, the present inventors have achieved high sensitivity, sieve stability, and high durability when used under positive charging.

As a result of research conducted with Ben Hui on organic photoconductors, it was found that an electrophotographic photoreceptor obtained by dispersing a small amount in a binder with a transfer function has extremely high sensitivity and a positive charge with good stability. The present invention was made based on the finding that the sensitivity can be improved even under low conditions.

That is, the gist of the invention Fi, on a conductive support.

The binder with the hydrazone compound has the general formula (1)% (1) (wherein A represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocyclic ring containing a nitrogen atom within itself.) Particles of bisazo compound tricked by f! :/~-θ After the photosensitive layer dispersed in Ar5 and the provided photoreceptor were exposed to positive corona radiation, the photosensitive layer was exposed to a positive corona radiation. It consists of a method of photographing one child, including transferring and special feature 9.

The present invention will be explained in detail below.

The present invention is composed of a binder containing a hydrazone compound and a dispersion formed by dispersing particles of a specific light guide. Compounds and binders have the function of hole transfer. As the hydrazone compound, axiomatic ones can be used, but hydrazone compounds represented by the following general formulas ⅐ to (V), and particularly hydrazone compounds represented by the general formula ω are suitable. These hydrazone compounds may be used alone or in a mixture of two or more.

In the above formula, B'-wB", X and Y may be an aromatic hydrocarbon group which may have a substituent, such as a phenyl group, a naphthyl group, an anthryl group, or A good heterocyclic group is represented by an indolyl group or a carbazolyl group, and examples of the substituent include an alkyl group, an alkoxy group, or a dialkylamino IH alkylphenylamino group.

Diphenylamino groups, etc. are included. Also.

R1-"(6 represents an argyl group, an aralkyl group or an aryl group, m, n+ and Ht represent/or -, and t represents Q or/.

Representative examples of specific compounds? Shown in the table below.

Table / Table / Continued These hydrazone compounds are mixed with a common binder resin to form a binding agent. The mixture of the hydrazone compound with the binder resin is added to the resin 100.
(, a O/S-Ishi-〇〇The overlapping part is good and the length is preferably V″LJO and it is 730 parts by weight.

Binder resins include polymers and copolymers of vinyl compounds such as styrene, vinyl esters, acrylic esters, and memecryl esters, phenoxy-position polymers, polyvinyl acetals, polycarbonates, 1. polyesters, cellulose esters, silicone resins, Ure, tan bean fat, uncut 7
Known binders such as No. 10 polynisple can be used.

Melamine resin, isocyanate compounds, etc.? After mixing and forming a coating film of 7%, a heating cross-linking reaction is carried out and a 1% solubilization process is performed. : Ba-r-nder fat may also be used.

During this binding, for example, 3. A phenolic antioxidant such as S-G C butyl-q-hydroquinotoluene, a sensitizer such as a sensitizer, a known sensitizing dye, etc. may be added as necessary.

As photoconductive particles, the amount of P in 111 is ν! The bisazo compound (·τH, - is expressed by the bisazo compound (, I).

(1) In the formula, A represents a monovalent group of an aromatic hydrocarbon or a monovalent group of a heterocycle contained within the nitrogen atom. Representative examples of these compounds are all shown in the table below.

The azo pigment is mainly dispersed in the form of fine particles in a binder such as a hydrazone compound and a binder resin, and the content of the azo pigment is preferably 20% by weight.

A so-called dispersed photosensitive layer in which a bisazo pigment represented by the above general formula (1) is dispersed in a binder consisting of these hydrazone compounds and a binder resin - continued coating on a conductive support and forming a photosensitive layer and constitute an electrophotographic photoreceptor. The film thickness of the dispersed photosensitive layer of the present invention is s~
The thickness is preferably 0 μm, more preferably 10 to 30 μm.

As the conductive support used in the photoreceptor of the present invention, a variety of known ones can be used. For example, aluminum, copper, nickel metal drums, belts, or laminates of these metal foils.

The deposit is opened. Furthermore, examples include plastic films, plastic drums, and paper which are conductively treated by coating a metallurgical material such as gold) F4 powder, carbon black, steel iodide, or tin oxide together with a binder resin as necessary.

Further, a known adhesive barrier layer may be provided between the photosensitive layer of the present invention and the conductive support. Examples of the barrier layer include layers of polyamides, caseins, polyurethanes, etc., having a thickness of about O,OS/μm.

<Effects of the Invention> The electrophotographic photoreceptor of the present invention thus obtained has excellent sensitivity under positive charging, excellent potential stability during repeated use, and almost no fatigue unlike original memory. It has extremely stable characteristics, and by using a single photoreceptor under positive charging, images of extremely stable rendition quality can be obtained, making it possible to obtain images of extremely stable rendition quality, and to use electronic photography such as Ga printers as well as digital photography. It can be used in a wide variety of fields.

<Examples> Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example / 10% tetrahydrofuran melting of polymethyl methacrylate INim (BR-gs manufactured by Mitsubishi Rayon Co., Ltd.) /
Parts by weight of DO, Compound H-/Toracin'/in the above table/
0 parts by weight, 0 parts by weight of an electron-attracting compound having the following structure, and 0 parts by weight were mixed and uniformly dissolved.

Next, a portion of Compound 4/IM in the above table was subjected to a dispersion treatment with the above ih using a sand grinder. This dispersion was applied onto a 73μ polyester film on which aluminum had been vapor-deposited so that the film thickness after drying would be 10μ.

This sample was analyzed using Kawaguchi Paper Analyzer SP-172.
The electrophotographic characteristics were measured at 10'7.g. OKV
The initial potential at the corona voltage is 1'yq! RV half-reduced Russian veteran guny! ; tux sθC1 residual potential was /qV.

Example-~q Bisazo compound and L7
However, the results shown in Table 3 below were obtained.

Table-3 Example! Hydrazone compounds or compounds in the table above.

A sample was prepared in exactly the same manner as in Example N/, except that it was H-1 and did not contain a single-child attracting compound.

In addition, when the electrophotographic characteristics were evaluated in the same way, it was ranked -4th in the initial stage.
tsov halved Russia's original bond yu, s tuxaec, residual potential/zaV.

Example 6 A sample was prepared in exactly the same manner as in Example S, except that the hydrazone compound was Compound 4) 1-t in the table above. The electrophotographic characteristics of this photoreceptor were that the initial potential was 3 izv half-decreased, and the initial potential was 7 tuxs θC.

In Example 1, samples were prepared by changing the compound and the additive amount, and the electrophotographic properties were evaluated.

The results are shown in Figure 7l.

Hiroo Tabi Mdo I1g Example/The following method was used to determine the repeat stability of the sample prepared. That is, charging (corona 4 pressure t 7 K
J17) and '5air original (a o o tux6ec)
This was repeated too many times to observe changes in characteristics. As a result, gold layer 5 shows excellent fC cycling stability. For comparison, samples were prepared in the same manner as in the case of IJ Yamaj'/lj/, except that the following bisazo pigments were used, and all evaluations were carried out in the same manner as in Comparative Example. The results are shown in Table 5.

? ″k　　　　　　　　　　OH.

table ! Example 9 Diameter tOrmn of mirror-finished photosensitive layer having the composition of Example/
The photosensitive drum was coated on an aluminum drum with a photosensitive layer having a thickness of 10 μm.

When this was modified to a commercially available copying machine and a positively charged thread, and a live photo test was conducted, clear images were obtained without any image defects during a durability test of 10,000 sheets from the beginning.

Claims (1)

[Claims] (1) General formula (I) ▲Mathematical formula, chemical formula, table, etc. are present in the binder containing the hydrazone compound on the conductive support▼・・・・・・・・・
(I) Contains 1 to 20% by weight of dispersed particles of a bisazo compound represented by (wherein A represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocycle containing a nitrogen atom in the ring). 1. An electrophotographic method, which comprises charging an electrophotographic photoreceptor provided with a photosensitive layer by positive corona discharge, followed by imagewise exposure, development, and transfer.