JPS58217408A - Manufacture of photoconductive cadmium sulfoselenide - Google Patents

Abstract

PURPOSE:To obtain photoconductive CdSSe capable of forming a high contrast image from the early stage of image formation by adding a flux to a mixture of CdS with CdSe obtd. by simultaneously adding Na2S and ammonium selenite to an aqueous Cd salt soln. and calcining the flux added mixture. CONSTITUTION:An aqueous Na2S soln. and an aqueous NH4HSe soln. are simultaneously charged into an aqueous soln. of >=1 kind of water soluble inorg. or org. Cd salt such as CdCl2, CdSO4 or Cd acetate while stirring the soln. to coprecipitate CdS with CdSe. The coprecipitated mixture of CdS with CdSe is washed, dehydrated, and dried. A flux is added to the dried mixture by >=15pts. wt. per 100pts.wt. mixture, and they are well mixed, put in a quartz crucible, and converted into a solid soln. by calcination at a temp. >=50 deg.C above the m.p. of the flux to obtain photoconductive CdSSe.

Description

Detailed Description of the Invention The present invention relates to a method for producing photoconductive cadmium selenide sulfide, and in particular a method for producing cadmium selenide sulfide for producing highly crystalline and uniform particles. Photoconductive cadmium selenide sulfide (CdS-8e) is typically used as a photosensitive material in electrophotography.

The general production method is to precipitate cadmium sulfide particles by causing hydrogen sulfide to act on a water-soluble salt of cadmium such as sulfuric acid, cadmium, cadmium chloride, or cadmium nitrate, and then to precipitate cadmium sulfide particles and cadmium selenide particles. The mixture is mixed and fired at a high temperature to create a cadmium selenide sulfide solid solution. That is, photoconductive cadmium sulfide selenide is added to a mixture of cadmium sulfide particles and cadmium selenide particles as a fluxing agent in CdCj!
! It is generally produced by mixing a halide such as Z + ZnCl2 and firing to form a solid solution of cadmium sulfide and selenium. However, in the conventional method, Cd5Se produced through the sintering process has a large number of defects near the surface. These surface defects become trap levels for photocarriers, increasing the optical memory of Cd5Se, that is, slowing down the photoresponse speed, making photoreceptors made using such Cd5Se suitable for high-speed copying machines. This results in insufficient electrostatic contrast between bright and dark areas.

In addition, the particle shape of Cd5Se produced by the above method is based on secondary particles, which are strong aggregates formed by particles aggregating with each other, and these secondary particles are formed by three-dimensional aggregation. They can be shaped like nodules, aggregated two-dimensionally and shaped like a flat plate, and some of them are large, ranging in size from a few microns to several tens of microns. A photoreceptor made using Cd5Se containing a large number of particles has a poor surface condition, resulting in images that are extremely rough and have insufficient resolution.

Furthermore, in the case of a photoconductor further provided with an insulating layer, the insulating layer may seep into the Cd5Se layer, making it difficult to obtain a good photoconductor.

Furthermore, when looking microscopically at the mixed state of CdS particles and CdSe particles, the presence of non-uniform parts is essentially unavoidable since both particles have a unique particle size distribution. It is. This non-uniformity of mixing ultimately increases the instability of the electrophotographic properties of the Cd5Se produced1, and results in particles with poor coating properties and coating properties.

The present invention solves these drawbacks of the conventional methods, and has the following features: (1) high contrast images can be formed from the initial stage of image formation, and (2) cadmium selenide sulfate particles have a uniform shape. In addition, since it is a single particle, it has good resolution and excellent coatability. (3) It is less affected by humidity and temperature. (4) It has little deterioration due to repeated electrophotographic processes, and has excellent durability and pressure. It is an object of the present invention to provide a method for producing photoconductive cadmium selenide sulfide having excellent properties.

The method for producing photoconductive cadmium selenide sulfide according to the present invention is to sulfurize a cadmium salt aqueous solution.
At least 50°C above the melting point of the flux is added by weight part or more.
It is characterized in that it is fired at a temperature higher than that.

The cadmium selenide sulfide produced by the present invention has high crystallinity, and when observed with a scanning electron microscope, it is a single particle with no agglomeration of particles, and its surface is smooth. Therefore, cadmium sulfate selenide produced through such coprecipitation and sintering processes has extremely few crystal defects near its surface that can become trap levels for optical carriers, and can be dispersed in a tree binder for electrophotography. A high electrostatic contrast can be obtained by applying the photosensitive plate to a high-speed copying machine by coating it on a support, creating a photoconductive layer, and then forming an insulating layer thereon if necessary to create a photosensitive plate. It is permitted to do so. In addition, since the cadmium selenide sulfide powder obtained by the present invention has a uniform particle shape and uniform particle size, the coated surface of the photoconductive layer created is dense and smooth, resulting in very high quality images. is obtained.

However, the performance as a high-quality electrophotographic photoreceptor is still poor in terms of image stability in low-humidity environments and electrostatic contrast values under temperature and humidity conditions in tropical regions, such as temperatures of 35°C and relative humidity of 85%. It is possible to have the following.

Furthermore, cadmium selenide sulfide has higher sensitivity than cadmium sulfide, and its spectral sensitivity range also extends toward longer wavelengths.

The water-soluble cadmium salt used in the present invention is
CdC1z, CdSO4, Cd(NO3)z, Cd
a(PO4)2. .

CdzP207. Cd(BO3)2. Cd(Br0
3)2. CdBr2. CdC05Cd(CIOs
)2, inorganic salts such as CdI2 and cadmium acetate,
Organic salts such as cadmium oxalate. While stirring an aqueous solution of one or more water-soluble cadmium salts selected from the water-soluble cadmium salts, an aqueous solution of acidic ammonium selenite [chemical formula (NH4-(H)Seo3)] and a sodium sulfide aqueous solution are simultaneously added. Cadmium sulfide (chemical formula: CdS) and cadmium selenide (chemical formula: cdse) are co-precipitated.At this time, the concentration of the water-soluble cadmium salt aqueous solution is 0.1 to 3 m0A/l, %Kld.
'0.5 to 2rrlO4/l is preferred. P of the aqueous solution
H is acidic with a value of 5 or less, and the reaction temperature is 95°C or less, especially 60°C.
~80°C is preferred. The total reaction time is determined by the rate at which the acidic ammonium selenite aqueous solution and the sodium sulfide aqueous solution are added, but from the viewpoint of productivity, it is preferable to feed them so that the reaction is completed in 1 to 3 hours. Washing the mixture of CdS and CdSe co-precipitated in this way,
Dehydrate and dry. Drying is carried out at 250° C. or lower for 5 to 20 hours.

Next, after thoroughly mixing the mixture and a flux, the mixture is placed in a quartz crucible and fired to form a solid solution, thereby obtaining photoconductive Cd5Se.

The flux used in the present invention is a flux commonly used when diffusing an activator into CdS, and includes CdCe2, CdCe2,
ZnCl2. KCJ! , NaCjt! , NH4
Cl, Cd5O4, etc. (7) It is a mixture of one or several types in an appropriate ratio. A preferred example of a mixture used is a mixture of CdCl12 and an alkali metal chloride.

I get kicked. Representative examples of alkali metal chlorides include NaC6 and KC1. The content of the alkali metal chloride in the entire flux is preferably 9 Io or less and 10 or more mole.

In the present invention, the amount of flux in the first firing step is Cd
It is preferably 15 parts by weight or more, particularly preferably 20 to 50 parts by weight, per 100 parts by weight of the mixture of S particles and cadmium selenide particles.

If the amount is less than 15M parts, the Cd5Se particles produced will be sintered and become coarse particles, the surface shape will be uneven, the potential retention will not be sufficient, and the Cd5Se particles will have poor resolution.
It becomes e. Furthermore, if the calcination is performed at a temperature lower than 50°C higher than the melting point of the flux, the produced Cd
5Se particles have a large particle size and have poor resolution and coating properties, and the electrostatic contrast of the initially formed image is often low.

In addition, in the manufacturing method of the present invention, the firing temperature is 600°C.
The following are preferred. Further, from the viewpoint of yield, the amount of the flux added to 100 parts by weight of the mixture of CdS particles and cadmium selenide particles is preferably 65 parts by weight or less.

In order to further improve the crystallinity of the Cd5Se produced in this manner, it is also effective to sinter it again.

The amount of flux in the second firing (re-firing) step is preferably 20 parts by weight or less, particularly preferably 0 to 1'OM parts, per 100 parts by weight of cadmium sulfur selenide particles. If it exceeds 20 parts by weight, the crystal growth of the produced CSSSe will be excessive, resulting in poor resolution and coating properties. Further, the firing temperature in the second firing step is preferably 400 to 500°C.

Example l CdSO4 temple 7.5 rnoA, il! Sulfuric acid (9
8%) tall.

Dissolve 7.5 X 10-3 molj of Cu5Ot% in deionized distilled water to bring the total volume to 141. While stirring the mixture at 80 DEG C., a 30 mol aqueous solution of (NH4)(H)SeO3 was added at a rate of 10@-min.

At the same time, a 15% by weight aqueous solution of Na 2 S is introduced at a rate of 302/min. (The injection of NI(4)(H)SeO3 continues for 75 minutes, and the injection of NazS continues for 90 minutes.

Thereafter, the reaction solution is left to stand for 30 minutes while stirring at 80C, and then stirring is stopped and left to stand for 30 minutes.

Next, drain the supernatant, add 15 t of fresh deionized distilled water, and stir for 15 minutes. After that, stirring was stopped and the mixture was allowed to stand for 30 minutes. Drain the supernatant and add 15 t of fresh deionized distilled water.

After repeating this washing step a total of five times, the precipitate was filtered, dehydrated, and dried at 150° C. for 12 hours.

CdC1h 801P, Na to the dry particles 400 g
After adding C711202 and mixing well, the mixture was filled into a quartz crucible and fired at 530° C. for 30 minutes.

(From the phase diagram, the melting point of the mixed flux of CdC1h and NaC6 corresponds to 426°C, which is the melting point of Cdl12.2NaC6.) The surface of the Cd5Se particles thus obtained is shown in an electron micrograph at 10,000 times magnification. According to the results, it was observed that the particles were very smooth and each particle was a single particle with a diameter of 3 to 7 μIn.

After dispersing these Cd5Se particles in a vinyl chloride/vinyl acetate copolymer, they were coated on an aluminum substrate to a thickness of 40 μm and dried, and a photosensitive gK15 μm thick polyester film was pasted thereon to form a three-layer photosensitive film. When the body was obtained, the surface was very smooth. When this photosensitive plate was subjected to a high-speed electrophotographic process of primary charging, then photoimage exposure, AC static elimination, and then full-surface exposure, high-quality images with high electrostatic contrast and sufficient resolution were obtained. The resolution was 6 lines/. This photosensitive plate was heated at a high temperature of 35°C and a humidity of 85%. After being left in high humidity for 24 hours, the image was produced again using a copying machine. As a result, a good quality image was obtained with no decrease in contrast between bright and dark areas and no decrease in sensitivity. Furthermore, after leaving this photoreceptor in a copying machine placed in a low-temperature, low-humidity atmosphere with a temperature of 5°C and a humidity of 10°C for 12 hours, the dark area potential was measured.
The 0th one is 485V and there is almost no difference. Further, the change in potential contrast measured at 5°C and 50°C was as small as 2°V. Furthermore, when a durability test was conducted on 50,000 sheets of A3 size using an actual copying machine in an atmosphere of temperature 23° C. and humidity 55 cm, the potential contrast decreased by 25 V, indicating excellent stability.

Example 2 CdCJz in 0.6t of 10moJs concentrated sulfuric acid (98%)
Dissolve the mixture in deionized distilled water to bring the total volume to 141. Keep the mixture at 75°C and add (NH4) with stirring.
H) Inject 30 g of an aqueous solution of SeO3 at a rate of 4.2-min. At the same time, a 15% by weight aqueous solution of Na t S was added at a rate of 55% per minute. input at a speed of (NH4)(H)SeOs
The addition of Na2S continues for 80 minutes, and the addition of Na2S continues for 85 minutes. Thereafter, the reaction solution was allowed to stand at 75° C. for 30 minutes while being stirred, and then the stirring was stopped and the solution was left undisturbed for 30 minutes. The sample was then washed five times with deionized distilled water in the same manner as in Example 1, filtered and dehydrated, and dried at 200°C for 10 hours.

The molar ratio of CuC1v to Cd in the dry particles 400f is 5.
After adding X10-4, another 1 c CdCh 120 t
A mixed flux of KCJ 80 F and KCJ 80 F was mixed and thoroughly mixed, then filled into a quartz crucible and fired at 470° C. for 60 minutes.

Next, the fired product is washed and dried to isolate the casse particles. The Cd5Se particles were filled into a quartz crucible and fired at 1.45'0°C for 60 minutes.

According to an electron micrograph of the Cd5Se particles obtained in this way, it was observed that they were extremely smooth and each particle was a single particle with a diameter of 3 to 7 μm. Ta.

After that, the obtained Cd5 was subjected to the same process as in Example 1.
When Se particles were made into a photoreceptor and evaluated, good results similar to those in Example 1 were obtained. (fL oh, CdCjtz and KC
From the phase diagram, the melting point of the mixed flux I is 3, which is the melting point of KCdCls.
Corresponds to 90°C. ) Applicant: Canon Co., Ltd.

Claims (1)

[Claims] 1. 1 for 100 parts by weight of a mixture of cadmium sulfide and cadmium selenide obtained by simultaneously adding sodium sulfide and ammonium selenite to an aqueous cadmium salt solution.
5 parts by weight or more of a fluxing agent is added, and the melting point is 50% higher than the melting point of the fluxing agent.
A method for producing photoconductive cadmium selenide sulfide, which comprises firing at a temperature higher than u.