Siemens Aktiengesellschaft

Eberhard Bayer

Karl Kempter

An x-ray electro-photographic recording material is formed of a photo-conductive layer (1) comprised of a selenium-arsenic alloy and positioned on a transparent electrode layer (4), which is positioned on a further layer (3) comprised of an x-ray luminophore and positioned on a reflective surface (2a) of a film carrier layer (2). In usage, with a positive corona charge on the free photo-conductive layer surface (1a) before x-ray exposure, the luminophore-containing layer (3), during x-ray exposure, converts a component (5) of the x-ray radiation (.gamma.) not absorbed by the photo-conductive layer (1) into visible luminescent light (6) which effects an increase of sensitivity in the photo-conductive layer (1). This recording material can be used in x-ray photograph devices.

X-Ray electro-photographic recording material and method for generating

A device for electrophotographically copying wherein for writing a charge pattern into a suitable photo-conductive layer with differing electron mobility and hole mobility a relatively long wave length of light is used which has a penetration depth comparable with the thickness of the layer and which has a quantum energy which corresponds to the energy of deep traps for the less mobile kind of charge carriers. Due to the long life of the charge carriers in the deep traps, the newly applied charges of opposite polarity remain on the exposed locations for a relatively long time since the charge has been caught in the traps whereas the unexposed locations are repeatedly charged again to maintain an undisturbed potential such that the charge pattern is retained for a longer time even with continued exterior charging. So as to erase the charge pattern a correspondingly light beam of shorter wave length is utilized which has a penetration depth that is small relative to the thickness of layer so as to cause the deep traps to be quickly removed through recombination of charges.

Device and method for producing a number of copies by

A device is disclosed which is useful in an electrophotographic copier for stabilizing and increasing contrast potential. The device is employed for extinguishing a recorded, electrostatic charge image. The device has one or more light sources which provide a spectral distribution comprising a first spectral range of maximum photoconductivity production and a radiation energy which is three to ten times a radiation energy present in a second spectral range. The second spectral range is located at a wavelength determined by a maximum of a product of photoconductivity production and penetration depth. An additional radiation energy distribution in remaining portions of the spectral distribution has a radiation energy not exceeding five to ten percent of the radiation energy of the first range.

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Munich, Germany

Eberhard Bayer