JPH01219838A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To realize high sensitivity and low residual potential and to reduce deterioration in characteristics at the time of repeated uses by incorporating a specified triaminobenzene derivative as an electric charge transfer material in a photoconductive layer. CONSTITUTION:The photoconductive layer contains as the charge transfer material one of the triaminobenzene derivatives represented by formula I in which each of R1-R6 is lower alkyl, lower alkoxy, optionally substituted aryl or such aralkyl, optionally same or different, thus permitting the triaminobenzene derivatives contained in the photoconductive layer to be superior in positive hole transfer ability, accordingly, the obtained electrophotographic sensitive body to be enhanced in transfer efficiency of carriers generated in the photoconductive layer, to realize high sensitivity and low residual potential and not to bring about deterioration in characteristics.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to an electrophotographic photoreceptor in which a photoconductive layer is formed on a conductive support, which achieves high sensitivity and low residual potential, and maintains characteristics even after repeated use. In order to provide an electrophotographic photoreceptor with little deterioration, the electrophotographic photoreceptor is prepared by containing at least a triaminobenzene derivative represented by the following structural formula I as a charge transport substance in the photoconductive layer of the electrophotographic photoreceptor. Configure.

[Industrial application field]

The present invention relates to an electrophotographic photoreceptor, and more particularly to a novel functionally separated multilayer electrophotographic photoreceptor using a triaminobenzene derivative as a charge transport material. The electrophotographic photoreceptor of the present invention can be widely applied to copying machines, φ printers, and the like.

[Conventional technology]

The electrophotographic process consists of charging, exposure, development, transfer, and fixing, and prints are obtained by repeating these steps. Charging applies a uniform positive or negative electrostatic charge to the surface of a photoconductive photoreceptor. In the subsequent exposure process, electrostatic latent scratches corresponding to the image information are formed on the photoreceptor by irradiating the photoreceptor with laser light or the like to erase the surface charge on a specific portion. Next, this latent image is electrostatically developed with a powder ink called toner, thereby forming a visible image of the toner on the photoreceptor. Finally, this toner image is electrostatically transferred onto recording paper and exposed to heat and light.

Printed matter can be obtained by fusing with pressure or the like. Conventionally, inorganic photoreceptors typified by selenium-based photoreceptors have been widely used as photoreceptors having photoconductivity as described above. This inorganic photoreceptor is highly sensitive and resistant to mechanical abrasion, making it suitable for high-speed, large-scale machines. However, it must be recovered due to the fact that it must be destroyed by vacuum evaporation and is harmful to the human body. However, due to such reasons, the system cost is high and it is difficult to apply it to maintenance-free, small, low-cost machines.

Mg-containing photoreceptors have been developed as an alternative to inorganic photoreceptors. This material can be manufactured by a coating method, which makes it easy to reduce costs through mass production, and because it has a wider range of materials to choose from than inorganic photoreceptors that use inorganic materials such as selenium, non-hazardous compounds can be selected. It has the advantage of being maintenance-free.

Among these, functionally separated laminated photoreceptors in which a charge generation layer and a charge transport layer are laminated are attracting attention. Here, the charge generation layer has the function of absorbing incident light and generating electron-hole pairs (carrier pairs), and the charge transport layer retains a charge on its surface and carries carriers generated in the charge generation layer. It has the function of transporting one side of the photoreceptor to the surface of the photoreceptor to form electrostatic latent scratches. The charge generation layer is formed by depositing a charge generation substance that actually absorbs light and generating carrier pairs, or by dispersing it in a binder resin. Azo pigments, phthalocyanine, and the like are known as charge-generating substances, and polyester, polyvinyl butyral, and the like are used as binder resins. The charge transport layer is formed by dissolving a charge transport substance having carrier transport ability in a binder resin. Charge transport materials include electron transport charge transport materials such as trinitrofluorenone and chloranil, which have the property of transporting electrons, and hole transport charge transport materials such as hydrazone and pyrazoline, which have the property of transporting holes. Polycarbonate, styrene-acrylic, etc. are used as the binder resin.

By separating the functions of the photoreceptor into two layers in this way, compounds suitable for each function can be selected almost independently, resulting in sensitivity of 9 spectral characteristics.

It is possible to dramatically improve properties such as charge retention, high-speed response, and mechanical wear resistance.

However, organic photoreceptors still have lower sensitivity than inorganic photoreceptors such as selenium, making it difficult to apply them to high-speed printers. In addition, as the charging-exposure process is repeated, the charge transport material deteriorates due to the ozone generated during charging and the laser irradiated with high brightness, and the charging potential decreases.
There is a peak at which printing quality deteriorates due to an increase in residual potential.

[Problem to be solved by the invention]

An object of the present invention is to provide an electrophotographic photoreceptor that achieves high sensitivity and low residual potential and exhibits little deterioration in characteristics even after repeated use.

[Means to solve problems]

According to the present invention, there is provided a photoreceptor obtained by using a triaminobenzene derivative represented by the following structural formula I as a charge transport material in a photoconductive layer.

Rv R4 (+) (R+, Rt, Rs, R4, Ri, and R@ may be the same or different, and each is a lower alkyl group.

Lower alkoxy group, aryl group which may have a substituent,
Represents an aralkyl group. ) Phthalocyanine is used as a charge generating substance.

Steel 7 talocyanine, aluminum chloride phthalocyanine,
Titanyl phthalocyanine, vanadyl 7-thalocyanine, indium phthalocyanine, various metal 7-thalocyanines, and azo pigments can be used. The charge-generating layer 1 is formed by vapor-depositing these charge-generating substances on a conductive support, or by coating and drying a mixture dispersed in a solvent together with a binder resin. The binder resin for the charge generation layer is selected from polyester, polyvinyl alcohol, polyvinyl butyral, polyamide, etc., taking into consideration the adhesion to the base and the dispersibility of the charge generation substance. The solvent is selected depending on the charge generating substance and binder resin used, and organic solvents such as tetrahydrofuran, dioxane, methanol, ethanol, dichloromethane, dichloroethane, toluene, and xylene can be used alone or in combination. Methods for coating the support include dip coating, spray coating, wire barcode coating, and doctor blade coating. Film thickness is 0.01~3
The thickness is preferably 1 μm or less.

As the conductive support, for example, aluminum is used.

Examples include metals such as metal parts, resins that have been made conductive by adding tin oxide, carbon, and the like.

Examples of the triaminobenzene derivative of the present invention used as a charge transport substance include compounds as shown in Tables 1 to 1 below.

These triaminobenzene derivatives are trihalogenated benzene represented by (R1 and Rt may be the same or different, respectively, and are a lower alkyl group and a lower alkoxy group.

Represents an aryl group or an aralkyl group that may have a substituent. ) It can be easily synthesized from a secondary amine represented by the following by a known reaction.

The charge transport layer can be obtained by dissolving the above-mentioned triaminobenzene derivative together with a binder resin in a solvent and drying the solution on the previously formed charge generation layer. The binder resin for the charge transport layer is polycarbonate or polystyrene.

Known materials such as polyacrylonitrile, acrylic-styrene, polyester, and polysulfone can be used. The solvent is selected as appropriate for the charge generation layer depending on the binder resin used. As for the coating method, the same method as in the case of the charge generation layer can be used. The film thickness is 5 to 50 μm, preferably 10 to 25 μm.

In addition to the triaminobenzene derivative (1), other charge transport substances such as hydrazone derivatives and pyrazoline derivatives may be added to the charge transport layer. Further, the stacking order of the charge generation layer and the charge transport layer may be reversed. Further, the invention can also be applied to a single-layer type organic photoreceptor in which the photoconductive layer is formed by mixing a charge generating substance and a charge transporting substance in a binder resin.

Furthermore, an undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and prevent thermal carrier injection. As the undercoat layer, resins such as polyvinyl alcohol, polyvinyl methyl, polyamide, and epoxy, or resins containing additives such as tin oxide, indium oxide, and titanium oxide are used.

[Effect]

The uninvented electrophotographic photoreceptor contains a triaminobenzene derivative with excellent hole transport properties in the photosensitive layer, which increases the transport efficiency of nine charge carriers generated in the photosensitive layer, resulting in high sensitivity and high sensitivity. This realizes a low residual potential. Furthermore, the triaminobenzene derivative 1 of the present invention exhibits excellent continuous stability because it is hardly susceptible to deterioration even by ozone or light irradiation.

〔Example〕

Example 1 1 part aluminum chloride phthalocyanine (parts by weight)
, 1 part of polyester, and 18 parts of dichloromethane were dispersed and mixed for 24 hours using hard glass beads and a hard glass pot, and then applied with a doctor blade onto the aluminum surface of the aluminum-deposited polyester film, and dried at 100°C for 1 hour to form a film. A charge generation layer having a thickness of 0.3 μm was formed.

Next, 1 part of the above triaminobenzene derivative (Y4),
One part of polycarbonate was dissolved in nine parts of tetrahydrofuran, and the solution was applied onto the previously formed charge generation layer using a doctor blade and dried at 80° C. for 2 hours to form a charge transport layer having a thickness of 18 μm.

A photoreceptor was thus obtained.

Next, this photoreceptor was corona charged at 15 KV, and 1
The surface potential after a second was set as Me (V), and from that moment on, exposure was performed with light of 780 nm. Find the time t8/2 until the surface potential reaches half of vo and calculate the half-reduction exposure amount E.
l/2 (μJ/cd) was calculated. Furthermore, the surface potential Vr (V) at 10t1/2 after the start of exposure was recorded, and finally at 6
One process was completed by eliminating static electricity using a 33 nm LED.

The result of repeating this process 10,000 times each? The results are shown in Table SK.

Example 2 Triaminobenzene derivative 4 as a charge transport material
Exactly the same procedure as in Example 1 was carried out except that A5 was used instead of A4. The results are shown in the table 0 Example 3 Triaminobenzene derivative A as a charge transport substance
Exactly the same procedure as in Example 1 was carried out except that 1615 was used instead of 40. The results are shown in Table 1.

Example 4 The same procedure as in Example 1 was carried out except that triaminobenzene derivative 22 was used instead of triaminobenzene derivative 4 as the charge transport material. The results are shown in Table 4.

Example 5 The same procedure as in Example 1 was carried out, except that Ivy 38 was used instead of the triaminobenzene derivative M4 as the charge transport material. The results are shown in Table IK.

Example 6 (Comparative Example) Same as Example 1 except that hydrazone represented by the following structural formula was used instead of the triaminobenzene derivative A4 as the charge transport material. Table i As can be seen from the table, the photoreceptor of the present invention was Even after repeated testing 10,000 times, there was almost no deterioration in characteristics. On the other hand, although the photoreceptor of the comparative example shows relatively good characteristics in the initial stage, after continuous testing, the charging potential and sensitivity decrease, and the residual potential increases, and the photoreceptor deteriorates (or becomes fatigued). I can see that you are doing it.

〔Effect of the invention〕

As described above, by using the triaminobenzene derivative I of the present invention as a charge transport material, it is possible to obtain an electrophotographic photoreceptor that has high sensitivity and low residual potential and does not suffer from deterioration of characteristics even after repeated use. Can be done.

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Claims (1)

[Scope of Claims] An electrophotographic photoreceptor having a photoconductive layer on a conductive support, characterized in that the photoconductive layer contains at least a triaminobenzene derivative represented by the following structural formula I as a charge transport substance. An electrophotographic photoreceptor. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (R_1, R_2, R_3, R_4, R_5, R_6 may be the same or different, and have a lower alkyl group, a lower alkoxy group, or a substituent. (Represents an optional aryl group or aralkyl group.)