JPS5859453A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain a zinc oxide type electrophotographic receptor suitable for recording using semiconductor laser beams, by providing as photoconductive layer consisting of zinc oxide, an electron affinitive compd., and a specified dye in an electrophotographic receptor. CONSTITUTION:A photosensitive layer consisting of zinc oxide-resin layer is formed on a conductive substrate to obtain an electrophotographic receptor. The photosensitive layer contains zinc oxide, a spectral sensitizer represented by the general formulaI(R is CH3, C2H5, CH2COOH, C2H4COOH, CH2=CHCH2 or n-C7H15; X is I, Br, Cl, or formula II; formula III is any of formulae IV-IX; and formula V is any of XI-XVI), an electron affinitive compound serviceable for an assistant spectral sensitizer, such as benzoquinone, chloranil, phthalic anhydride, dinitrobenzoic acid, or tetracyanoquinomethane, and a resin, and is formed on the conductive substrate, so it is made high sensitive to 700-1,000nm wavelength light, and the photoreceptor using this layer is suitable for an electrophotography using semiconductor laser beams.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zinc oxide electrophotographic photoreceptor particularly suitable for use in semiconductor lasers.

Recording devices such as laser printers that use laser light to form electrostatic latent images require electrophotographic photoreceptors that are highly sensitive to laser light. For such a high-sensitivity electrophotographic photoreceptor, for laser light such as VIS-argon laser (wavelength 488 and 515 nm (Z) long wavelength light in the visible range), zinc oxide, acid enhancer such as rose bengal or erythrosine is used. Books are known that have been spectrally sensitized by adding a sensitizing dye. However, semiconductor lasers (wavelengths of 700 to 1000) are smaller and cheaper than argon lasers.
There are almost no high-sensitivity electrophotographic photoreceptors that are suitable for visible to near-infrared long-wavelength light (nm visible to near-infrared long wavelength light).

An object of the present invention is to provide an electrophotographic photoreceptor that has high sensitivity to long wavelength light in the wavelength range of 700 to 1000 nm and is therefore suitable for use in a base conductor laser.

That is, the photoreceptor of the present invention has a photoconductive layer comprising zinc oxide, an electron-affinity compound, a dye represented by the general formula %, and a resin on a conductive support.

The electrophilic compound used in the present invention is used as a spectral sensitizing aid, and specific examples thereof include benzoquinone, chloranil, phthalic anhydride, dinitrobenzoic acid, and tetracyanoquinodimethane. A suitable amount is 0.02 to 0.5% Fi for the amount of zinc oxide used. If the amount used is less than 0.02% by weight, the sensitizing effect tends to decrease, but this is thought to be due to poor adsorption of the dye represented by the above general formula to zinc oxide. Moreover, if the amount used is more than 0.5% by weight, there is a tendency that the dark decay becomes faster and the sensitizing effect becomes worse.

Dyes of general formula I or 1 are used as spectral sensitizers. The amount used is 0.01 to 0.1 relative to zinc oxide.
6% by weight is suitable.

As the resin, conventionally known resins, such as highly insulating resins such as acrylic resin, silicone resin, polyester, vinyl acetate resin, styrene resin, alkyd resin, and urethane resin, are used. The appropriate amount to be used is 10 to 30 days per day of zinc oxide.

The conductive support may also be of a known type, such as a metal film; a metal-deposited support, or a plastic film.

To make the photoreceptor of the present invention, zinc oxide,
A photoconductive layer forming liquid in which an electron-affinity compound, a dye of the above general formula, and a resin are dissolved or dispersed in an organic solvent such as toluene may be coated and dried. Note that zinc oxide may be surface-treated with an electron-affinity compound in advance. In this case, zinc oxide is added to a solution containing the electron-affinity compound and dispersed, and then the dye (or its solution) of the general formula (or its solution) and the resin (or its solution) are added by evaporating the solvent or without evaporating the solvent. It is preferable to prepare a photoconductive layer forming solution in addition to the 11th step.

The present invention will be explained below with reference to Examples.

Example 1 3,5-dinitrobenzoic acid o as an electron affinity compound,
Zinc oxide
After adding 0OIi and dispersing it with an ultrasonic disperser for 20 minutes, toluene was distilled off at a temperature of 80°C with a rotary enovolator. Next, in the general formula, R-C
,)I,,X-I.

(Extreme absorption in solution state: 817 nm) -
Zinc oxide surface-treated as described above was added to a solution of 0,IJi' dissolved in a mixed solvent of methanol 12ON and dimethylformad 101, and 2
After 0 minutes of dispersion, the rotary evaporator
Methanol gold was distilled off at a temperature of 0°C. Add 40% of acrylic resin to this) toluene bath solution 40jl and toluene 100J
I was added and milled for 4 hours in a Zeel mill, and then milled for 10
Coated on a 0μ thick aluminum foil support and heated with hot air at 90℃ for 5 minutes.
An electrophotographic photoreceptor was prepared by drying for a minute and forming a photoconductive layer with a coating weight of 2,517 cm.

Example 2 p-chlorobenzoic acid as an electrophilic compound 2Nt) Dissolved in 10OII of toluene, in which 100J of zinc oxide
Zinc oxide was surface treated by adding J and dispersing with a homogenizer for 20 minutes. On the other hand, in the above general formula, R”C
,H,,x-z.

dye (absorption maximum a 923 nm in solution state) 0
．． 12Il was dissolved in dimethylformad. Next, while stirring the photosurface-treated zinc oxide dispersion using an agitator, the dye #1 solution was added dropwise to allow the dye to be adsorbed onto the zinc oxide, and after 30 minutes, while continuing to stir, the acrylic resin was removed. 50-toluene solution 4011 was added. Next, the resulting mixed solution was milled for 1 hour using an f-y mill, and then coated on a support and dried in the same manner as in Example 1 to form a photoconductive layer, thereby producing an electrophotographic photoreceptor. did.

Example 3 An electrophotographic photoreceptor was prepared in the same manner as in 2, using 1 g of p-flora=h-0 as the electron-affinity compound and using the above general formula as the dye.

Example 4 As a dye, in the general formula, R-'-C1H,,X-'I
.

(Maximum absorption in solution state: 771 nm) 0.
An electrophotographic photoreceptor was prepared in the same manner as in Example 3 except that No. 11 was used.

Example 5 As a dye, in the general formula, R-C, H,, X''-: 7
801m) 0.1 Ii was used for fic and others in Example 3.
An electrophotographic photoreceptor was prepared in the same manner as described above.

Example 6 In the above general formula, R is CM, g CHCH, as a dye.

X so-called Br.

(Absorption maximum in solution state: ? 60 nm) 0
．． An electrophotographic photoreceptor was prepared in the same manner as in Example 3 using 08I.

Example 7 As a dye, in the general formula RaaaC1H@, X=Br
.

(Maximum absorption in solution state: 760 nm) 0.
An electrophotographic photoreceptor was prepared in the same manner as in Example 3 using 08I.

Next, the surfaces of the photoreceptors of Examples 1 to 7 obtained as described above were charged with negative corona, and then charged with a wavelength of 700 to 950 nm.
Monochromatic light (by xenon lamp spectroscopy) of 10 nm
The attenuation of the blush potential was measured by irradiating at an interval of , and from this the sensitivity was determined as half Ift, the reciprocal of the amount of light in m. The results are shown in the table below along with the measurement wavelength. Note that both photoreceptors are 70
Photosensitivity to long wavelength light of 0 to 950 nm was observed.

In Examples 1 to 7, electrophotographic photoreceptors were prepared in the same manner as in Examples 1 to 7, except that no electron-affinity compound was used, and therefore the zinc oxide was not surface-treated with the compound. When the sensitivities were determined, they were lower than l/lO of the photoreceptors of Examples 1 to 7, respectively.

Patent applicant Ricoh Co., Ltd.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a photoconductive layer comprising zinc oxide, an electron-affinity compound, a dye represented by the general formula (%), and a resin on a conductive support.