JP2707630B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member provided with a photosensitive layer containing a naphthalocyanine compound.

(Prior Art) Conventionally, electrophotographic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductor such as selenium, cadmium, and zinc oxide have been widely used. Or, they were not always satisfactory in terms of printing durability and the like.

On the other hand, electrophotographic photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component have many advantages, such as being relatively easy to manufacture, inexpensive, and non-polluting and easy to handle. In particular, attempts have been made to develop a high-performance organic photoreceptor in which the carrier generation function and the transport function are shared by different substances, and have been receiving much attention in recent years (Japanese Patent Application Laid-Open No.
-67949).

In recent years, Ar lasers, He-Ne
Gas lasers such as lasers and semiconductor lasers are particularly promising as light sources for copiers and computer output printers having image processing functions such as intelligent copiers. It is drawing attention because it can be made smaller and lighter. Semiconductor lasers have lower output power than gas lasers, and have a longer oscillation wavelength (about 780n).
m or more), the spectral sensitivity of conventional photoconductors is too short on the short wavelength side, and some photoconductive compounds that can be used as photoconductors using a semiconductor laser as a light source have been proposed ( JP-A-60-19144 and JP-A-60-111248).

(Problems to be Solved by the Invention) However, although some of the conventional organic photoconductive compounds have been put to practical use, they are not always satisfactory in characteristics such as sensitivity, residual potential, and repetition stability. It is a fact.

In addition, the appearance of a novel photoconductive material having high sensitivity in a long wavelength region, which is a light emitting region of a semiconductor laser, is desired.

The present invention overcomes these problems, is stable against heat and light, and has excellent carrier generation ability in visible light and long wavelength region,
It is an object of the present invention to provide a photosensitive member having sufficient practical sensitivity to a long wavelength light source such as a semiconductor laser.

(Means for Solving the Problems) The present invention provides an electrophotographic photosensitive member having a photosensitive layer containing an amorphous naphthalocyanine compound represented by the following general formula [I] on a conductive support. .

(Where A is a halogen, oxygen, alkyl group, hydroxyl group,
An atomic group consisting of a trivalent or tetravalent atom having one or two kinds selected from cyano groups. Here, A is a trivalent or tetravalent central atom M and a halogen,
Oxygen, alkyl groups, hydroxyl group, or, indicated by M · Y or M · Y ₂ by a cyano group Y, Y is present outside the cover Ron cyanine molecule plane.

The compound represented by the above general formula [I] is Martin L. Kapl
an other molecular crystal liquid crystal (Mo
l. Cryst. Liq. Cryst.), 112 , 345 (1984). Specifically, TiO-naphthalocyanine, AlCl-naphthalocyanine, InCl-naphthalocyanine,
SiCl ₂ -naphthalocyanine, TiCl ₂ -naphthalocyanine,
Cu (CN) ₂ -naphthalocyanine, VO-naphthalocyanine, Sn
Cl ₂ - naphthalocyanine, Ge (OH) ₂ - naphthalocyanine, S
iO-naphthalocyanine, Si (OH) ₂ -naphthalocyanine, Ga
Cl-naphthalocyanine, JnBr-naphthalocyanine, PdCl-
Naphthalocyanine, Sn (OH) ₂ -naphthalocyanine, SnF ₂
- naphthalocyanine, GeF ₂ - naphthalocyanine, GeBr ₂
−Naphthalocyanine, GeCl ₂ −Naphthalocyanine, GeO−
Examples include naphthalocyanine, but preferably TiO
- naphthalocyanine, AlCl- naphthalocyanine, InCl- naphthalocyanine, VO- naphthalocyanine, TiCl ₂ - naphthalocyanine, and the like. More preferably, TiO-
There are naphthalocyanine and AlCl-naphthalocyanine.

As a method of forming a photosensitive layer containing amorphous naphthalocyanine, the naphthalocyanine is passed through a gaseous phase.
Method of reaggregating on a substrate of 100 ° C or less, generally, it is obtained by using a vacuum deposition method, a sputtering method, or the like. It is not limited.

The naphthalocyanine thin film is re-aggregated on the substrate by the above-mentioned method and is in an amorphous state.
A broad band having a half width of 3 degrees or more, preferably 7 degrees or more has a peak near θ = 10 to 40 °. The pressure at the time of vaporization is 1 Torr or less, preferably 0.1 Torr or less, more preferably 10 ^-4 Torr or less.

The electrophotographic photoreceptor of the present invention is characterized by containing the above-mentioned amorphous naphthalocyanine as a carrier-generating substance in a photosensitive tank on a conductive support, and its physical constitution may be any of known forms. . That is, a carrier generating tank mainly containing a naphthalocyanine compound as a carrier generating substance and a carrier transporting tank mainly containing a carrier transporting substance may be laminated on a conductive support, or the carrier generating substance may be transported by a carrier. A photosensitive layer dispersed in a substance may be provided. Since these may be provided via an intermediate layer, various configurations disclosed in JP-A-60-67949 and the like are possible.

As the conductive support used in the present invention, a metal plate,
A metal drum or conductive polymer, a conductive compound such as indium oxide, or a conductive thin layer made of a metal such as aluminum, palladium, or gold is provided on a substrate such as paper, plastic, or film by means of coating, vapor deposition, lamination, or the like. Is used.

The carrier generation layer has a thickness of 10Å to 100 あ り, preferably 100Å to 1μ. In addition, as described above, in addition to directly forming a film from the gas phase, it is separated from the substrate, made into fine particles by means such as a ball mill, dispersed in a suitable solvent with a binder resin, and coated on a conductive support. It is also possible to form a film by drying. In this case, it is preferable that the fine particles of the naphthalocyanine compound have a diameter of 5 μm or less, preferably 1 μm or less. The thickness of the carrier generating layer is from 0.01 to 20 µ, preferably from 0.05 to 5 µ. The ratio of the naphthalocyanine compound in the charge generation layer is 10 to 100% by weight, preferably 30 to 9%.
5% by weight.

The carrier transport layer can be formed by dissolving a carrier transport material in a suitable medium, applying the solution, and drying. As the carrier transporting material, for example, trinitrofluorenone,
An electron acceptor substance such as tetranitrofluorenone, or a polymer having a heterocyclic compound such as poly-N-vinylcarbazole in a side chain, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a pyrazoline derivative, Polyarylalkane derivatives,
Examples include hole transporting electron-donating substances such as phenylenediamine derivatives, hydrazone derivatives, amino-substituted chalcone derivatives, triarylamine derivatives, carbazole derivatives, and stilbene derivatives, but the carrier transporting substances used in the present invention are not limited to these. It is not something to be done.

The thickness of the carrier transport layer is in the range of 1 to 100 μ,
Preferably it is 5 to 50 µ.

When a binder is used for forming the carrier generation layer or the carrier transport layer, any binder can be used, and in particular, a hydrophobic and electrically insulating film-forming material having a high dielectric constant can be used. High molecular polymers are preferred. Examples of such a polymer include, but are not limited to, the following.

a) Polycarbonate b) Polyester c) Methacrylic resin d) Acrylic resin e) Polyvinyl chloride f) Polyvinylidene chloride g) Polystyrene h) Polyvinyl acetate i) Styrene-butadiene copolymer j) Vinylidene chloride-acrylonitrile copolymer k) Vinyl chloride-vinyl acetate copolymer l) vinyl chloride-vinyl acetate-maleic anhydride copolymer m) silicone resin n) silicon-alkyd resin o) phenol-formaldehyde resin p) styrene-alkyd resin q) poly-N- Vinyl Carbazole r) Polyvinyl Butyral (Effect of the Invention) The photoreceptor of the present invention has good sensitivity to long-wavelength light by using an amorphous thin film of a naphthalocyanine compound as a carrier-generating substance as described above, and can be used for ordinary copying. Half as well as machine It can be widely used in electrophotographic applications such as laser printers and laser facsimile machines as a photoreceptor having sufficient sensitivity to long wavelength sources such as conductor lasers.

(Examples) Next, the present invention will be described specifically with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 TiO-naphthalocyanine was heated and vaporized in a vacuum of 2 × 10 ⁻⁵ Torr using a tungsten boat. This was deposited on an aluminum plate at room temperature so as to have a film thickness of 2000 ° to form a carrier generation layer. The X-ray diffraction pattern from this naphthalocyanine is shown in FIG. It can be seen from the result that the obtained film is in an amorphous state. Further, a solution prepared by dissolving 200 mg of P-diethylaminobenzaldehyde diphenylhydrazone and 200 mg of a polycarbonate resin "Iupilon E-2000" (manufactured by Mitsubishi Gas Chemical Co., Ltd.) in 2.5 ml of tetrahydrofuran is applied, and transports a carrier having a thickness of 15 μm when dried. By obtaining the layer, an electrophotographic photoreceptor was prepared.

Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the central atomic group of the naphthalocyanine compound [I] as a carrier-generating substance was changed from TiO to AlCl.

Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the central atomic group of the naphthalocyanine compound [I] as the carrier-generating substance was changed from TiO to AlCl.

Comparative Example 1 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the carrier-generating substance was changed to β-type Cu-phthalocyanine.

The electrophotographic photoreceptor produced as described above was evaluated for electrophotographic characteristics as described below.

Corona charged with a voltage of -6 kV by a static method, held in a dark place for 10 seconds, measured the initial surface potential, and then exposed to white light using a tungsten lamp as a light source so that the sample surface illuminance was 20 lux. The time until the surface potential attenuated to 1/2 was measured to determine the sensitivity E1 / 2 (Lux · sec).

The sensitivity to long wavelength light was measured by the following method.

First, the photoreceptor was corona-charged in a dark place and held for 10 seconds, and then the photoreceptor was irradiated with monochromatic light obtained by separating the xenon lamp light to 800 nm using a monochromator. Then, the time (second) until the surface potential is reduced to half is determined, and the exposure amount (μJ
/ Cm ² ) was calculated.

 Table 1 shows the results.

As is clear from Table 1, the photoreceptor of the present invention has excellent sensitivity at around 800 nm, which is the oscillation wavelength of the semiconductor laser, as compared with the comparative example.

[Brief description of the drawings]

FIG. 1 is a view showing an X-ray diffraction pattern of naphthalocyanine obtained in Example 1.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Itsubo 8-3-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Pref. A) JP-A-63-55556 (JP, A)

Claims (2)

(57) [Claims] An electrophotographic photosensitive member having a photosensitive layer containing an amorphous naphthalocyanine compound represented by the following general formula [1] on a conductive support. General formula [I] (Where A is a halogen, oxygen, alkyl group, hydroxyl group,
An atomic group consisting of trivalent or tetravalent atoms having one or two selected from cyano groups. ) 2. The method according to claim 1, wherein the maximum value of the X-ray diffraction peak of the naphthalocyanine compound exists between 2θ = 10 ° to 40 °, and has a broad peak whose half width is 3 ° or more. 2. The electrophotographic photosensitive member according to claim 1.