SU1603335A1 - Electrophotography material - Google Patents

Abstract

The invention relates to electrophotography and allows improving the quality of the material to increase the initial charging potential per unit thickness of the layer, the time of its dark half-life and eliminate fatigue, as well as increase its durability. A photosensitive layer consisting of a polymer binder and a photoconductor based on ZN GA ₂ SE ₄ with a thickness of 10–20 µm is deposited on a low-resistance electrically conducting substrate. The ratio of semiconductor and binder is 3-5: 1. 1table

Description

The invention relates to electrophotographic materials and can be used to record and store information.

The purpose of the invention is to improve the quality of the material in order to expose the initial potential of charging per unit layer of the layer, the time of its dark half-life, the elimination or fatigue, as well as the increase in its durability.

Electrophotographic material was prepared as follows.

PRI me R s 1-8. First, a compound is obtained. For this purpose, the method of two-temperature synthesis is used. for the fusion of the initial components with purity: Zn - 99.999%, C, a - 99.999%, Se - 99.9999%. In a horizontally located furnace, preheated to VET C, an evacuated quartz ampoule containing a sample of the initial components of the compound

ZnGa, j.Seij. in stoichiometric ratio. The vial is arranged so that a third of its length protrudes from the furnace. After the portion of the ampoule inside the oven is heated to the oven temperature, the compound formation reaction starts to flow rapidly, accompanied by intense luminescence inside the ampoule. At the same time, selenium vapors that have not yet entered into reaction condense in the cold detached end of the ampoule, reducing the pressure of its vapors and thereby preventing an explosion. As the reaction proceeds, the ampoule is slightly pushed inside the furnace and a new batch of selenium is fed into the reaction portion of the vial. The reaction is resumed with the same intensity. In this way, the whole process is carried out until the components completely react. After the reaction is complete, the temperature in the furnace is increased to 1170 ° C (temperature

(L

00 & 9 01

melting the ZnGa.Se compound is 1160 ° C), the reaction product is remelted for 2 hours. Then, cooling is performed slowly, melting at a rate with a constant temperature gradient. In this way, crystal ingots of the compound of red-orange color are obtained.

At room temperature, the order of MO ohm-cm crystals (n-type conductivity), and the ratio of dark and light resistance at 10 Lx is 15; The maximum of its own photosensitivity is at 540 nm and is 2; 10 The optical band gap is 2.4 eV.

After that, an electrophotographic material is prepared by grinding the powder of the photocathode tube and dispersing it together with the binding medium in a ball valve for 1 hour. As a 25 binding medium, use is made of a solution of polyvinyl butyral of the brand PNH in ethyl alcohol or polystyrene (benzene solvent ), or silicone varnish K-55 (solvent toluene), or acrylic ZO E-216 copolymer (solvent toluene).

The weight ratio of the photoconductor –binder takes 3-7: 1, respectively. The homogeneous suspension, obtained after the dispersion process, is applied on a laboratory sizing machine (using a bathing roller on an electrically conductive substrate made of degreased and pickled metal foil or electrically conductive paper. The substrate can be rigid or flexible and have any thickness Photosensitive The layer containing the photoconductor and the binder has a thickness of 10-24 o / km (see table 45).

With constant dispersion times and watering rates for the slurry of tol1cin obtained layers, the viscosity of the slurry is determined mainly, 5Q depends, in turn, on the ratio of substances immersed in the ball mill. With a constant amount of photoconductor and viscosity binder, the suspension depends on the amount of solvent.

To obtain layers with a thickness of 10-24 microns, 1 g of a photoconductor from 0.2 g is immersed in a ball mill

polyvinyl butyral binder and 1.8-3.2 ml of ethyl alcohol solvent. The prepared layers are dried first at room temperature for 24 hours, and then at SO with 1 hour. The table shows the main electrophotographic parameters and characteristics of the made samples, as well as the prototype,

The basic electrophotographic parameters and characteristics of the layers are investigated by a contactless method on an electrometric installation with a vibrating sensor above the surface of the layer in a static mode). The electrification is carried out using a high voltage power unit BP-13-0.5. Exposure with white or monochromatic light is performed with a C10-300 incandescent lamp or VSU2-P monochromator using neutral light filters and a photogate. The energy illumination of monochromatic light is measured using a RTN-30 radiation thermoelement and an FPb device. When studying the kinetics of the potential drop under the light, a storage oscilloscope is used as an indicator, and the drop in potential in the dark is recorded using a switch or an recording device connected to the output of the U2-6 electrometric amplifier. .

The integrated photosensitivity and spectral distribution are determined by the half-decay of the potential. The thickness of the photosensitive layer of the ESP material is measured with a MIN-8 microscope. The fatigue of the ESP material from ZnGaJie is determined by varying the number of charge-light cycles after 10 continuous cycles. The durability of the electrophotographic material is defined as the ratio of the photosensitivity of the material after 3 and 6 months to the original.

As can be seen from the table, the proposed electrophotographic material has all the parameters superior to the prototype: the value of the initial potential per unit thickness of the working layer is 65-82%; the dark half-time of the potential is 1.8-3.0 times; residual potential 1.8-3.0 times.

The durability of the material remains almost unchanged for 6 months. As a result of comparing these material parameters, the dark half-life and the residual potential of the initial samples and after 10 charge-illumination cycles it is clear that the proposed material does not have fatigue in the mode of tests performed.

The production technology of the proposed electrophotographic material can be carried out using existing equipment.

Claims (1)

Invention Formula An electrophotographic material consisting of a low-resistance electrically conductive substrate and deposited on it. 1603335 photosensitive layer made of inorganic .Ga-Se-containing photoconductor and polymer binder, which differs from the fact that, in order to improve the quality of the material to increase the initial charging potential per unit thickness of the layer, the time of its half-life and eliminate fatigue ; as well as increasing its durability, the photosensitive layer is made 10-24 µm thick from the photoconductor ZnGa2 Se4 with the ratio of the latter to the binder 3-7J1 IT p and n with h "N and e: Sj - photosensitivity. Through 3 carried; Sj - (yukostuvstnneynoet through "" and sensitivity; Cj - the rate of that dropout after 3 months; tj - the speed of the textual capacity of the potential drop through € carried; Cn - the rate of tempo decline of potential; L - time of the new range after 10 cycles; ОД., - residual potential of cherz 10 cycles.