GB838625A - Electroradiography - Google Patents

Abstract

838,625. Electrophotographic processes. RADIO CORPORATION OF AMERICA. May 24, 1956 [June 23, 1955], No. 16159/56. Class 98(2) An X-ray image is obtained by the method of xerography using as the X-ray sensitive coating finely divided photoconductive zinc oxide in an electrically insulating film-forming binder. The coating may be on a paper or other flexible insulating backing. An X-ray image of the object may be obtained directly on the surface of the object itself or on a wrapper or container having the object within, by providing one side of the surface of the object, wrapper or container with the X-ray sensitive coating, providing a uniform electrostatic charge on the coating, exposing to X-rays through the uncoated side which is opposite the coated side, and developing the image on the surface, wrapper or container. Examples are given of the formation of an image on the casing of a transistor or on the skin of a human arm. In the apparatus shown in Fig. 6, the objects to be X-rayed 10 are placed on an endless belt 30 which conveys them past stations which perform the operations of coating one side with the X-ray sensitive coating at 16, drying the coating at 18, charging at 20, exposing through the belt from source 1, developing at 24 and fixing at 26. Alternatively, as shown in Fig. 4, a tape 12 is provided with the X-ray sensitive coating which is charged at 20, the objects 10 being fed on to the belt before exposure and removed after exposure, and the images then developed at 24 and fixed at 26 on to the tape itself. In a further example, the objects are not loaded directly on to the X-ray sensitive tape 12 but are placed on an X-ray transparent belt which passes over the top portion of the tape 12 in synchronism therewith. Provision may be made for coating the tape 12 with the X-ray sensitive coating before the uniform charging step. The developer powder may be applied by a brush such as a camel's hair brush or a " magnetic brush, or by powder cloud or cascade methods. The developer powder may be a polystyrene resin mixed with carbon black and dyes, with a carrier of glass beads or iron powder. Specification 721,944 is referred to. Reference has been directed by the Comptroller to Specifications 774,433 and 798,184.