CS243748B1 - Elektrofotografiokó deska - Google Patents

Abstract

The electrophotographic plate between the metal substrate and the selenium layer contains a vaporized layer of the composition Aβ28χ, where 3.2 x 8. It may also contain an intermediate layer © of the composition /AsgS^/ySe^y, where x has the above meaning and is from 0 to 1, on which a selenium layer is vaporized, which may be enriched with other elements, e.g. arsenic, tellurium and sulfur.

Description

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Elektrofotografiokó deska

The electrophotographic plate between the metal substrate and the selenium layer comprises a vaporized layer having the composition Αβ ₂ 8 _χ , where 3.2 x 8. The selenium layer is vaporised and can be enriched with other elements such as arsenic, tellurium and sulfur.

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243 748

The present invention relates to a process for preparing an electrophotographic plate for radiography and reproduction techniques.

In electrophotography and X-ray recording, plates are used where the photosensitive layer consists of selenium enriched with some elements such as arsenic, sulfur, tellurium or the like. is deposited on the A32S3 layer, which serves as a blocking layer.

The disadvantage of using A82S3 between the conductive pad and the photosensitive layer is that the vaporization of AS2S3 units does not occur during vapor deposition. There are AS4S5, AS2S2, S2 and others molecules present. A layer containing AS4S4 molecules, sulfur chains is formed on the metal substrate and only a small amount of arsenic is bound to AS2S5 structural units immediately after steaming. Thus, the A82S5 summary composition layer forms a heterogeneous system sensitive to temperature and radiation. The radiation of sufficient energy or tempering results in the formation of a polymer structure close to that of the material to be melted. This shows that the electrophotographic plate containing the AS2S3 layer is unbalanced after fabrication and that operations to ensure the steady state are required.

This disadvantage is overcome by the construction of the electrophotographic plate according to the invention. It is based on the finding that the layer with the composition Αβ2δχ, where 3.2 <i.x <r_8 has a significantly reduced sensitivity to radiation and temperature. Its other advantage is that it has a higher electrical resistance than the AsgS layer? and effectively prevents injection of charge carriers from the metal layer into the selenium layer. This layer can therefore advantageously be used as a blocking layer between the metal backing and the selenium layer.

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A layer with the composition As ₂ Sx, where 3.2 µm x 8 can be vaporized onto a metal substrate and a layer of photosensitive selenium or selenium enriched with other elements can be applied to this layer. It is also possible to form interlayers of variable composition of / AsgSx/ySej.y, where 3.2 << x <^ - 8 and y vary from 1 to 0. This ensures a smooth transition of the composition between layers and avoids narrow areas with high electric field values that can negatively affect the transport of electric charge generated in the photoconductive selenium layer.

Figure 1 shows an electrophotographic plate. The aluminum support 1 carries a layer 2 having the composition As2Sx, where 3.2 < x &gt; L8, on which the selenium layer 2 is vaporized thereon.

FIG. 2 shows an electrophotographic plate in which a layer 2 of As2Sx is deposited on the aluminum substrate 1. in the interlayer 4 of the composition / As ₂ Sx / ySei_y, the composition continuously changes from Α82 £ 5χ in layer 2 to selenium layer 2 ·

The construction of the electrophotographic plate according to the invention will be described in the following examples.

Example 1

A layer 2 of As2S4 _f 5 of 2.5 µm thickness is deposited onto the aluminum support 1. A layer of 150 µm selenium 2 is steamed onto this layer. This plate can be used in radiography. The potential gradient in the dark after 10 minutes is 30% lower than a board containing an A82S3 layer instead of AS2S4.5 ·

Example 2

A layer 2 of 3 µm AS2S5 is steamed onto the aluminum support 1. the current passing through the AS2S5-containing steam boat is then gradually reduced while increasing the current through the selenium-containing boat. This interlayer is formed by four composition / As ₂ S ₅ / YSE ₁ .y where y changes gradually within the range of 1.5 .mu.m from 1 to 0. In this intermediate layer 4 is further vapor-deposited selenium layer thickness 2 ⁰

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The obtained electrophotographic plate was used for X-ray recording. It showed very good sensitivity, low potential gradient in the dark and also characterized by very good stability of the characteristics, which characterize the recording.

The advantage of electrophotographic plates containing a layer with a higher sulfur content than corresponds to the etechiometric composition of AS2S5 is also that there is no need to expose the plate to operations that stabilize the properties of the plate before use.

Claims (2)

SUBJECT OF THE INVENTION An electrophotographic plate comprising a metal substrate and a selenium layer, characterized in that between the metal substrate (1) and the selenium layer ($), a layer (2) having the composition As ₂ Sx ena is vaporized where 3.2 x x 8 8. An electrophotographic plate according to claim 1, characterized in that in addition to the layer (2) of the composition AS2Sx, it comprises an intermediate layer (4) of the composition (As2Sx) where y is 0 to 1 and x is as defined above, for which a selenium layer (3), which is optionally enriched with other elements such as arsenic, tellurium and sulfur.