(19)

(11)

EP 0 056 040 A1

(12)

(43) Date of publication: 21.07.1982 Bulletin 1982/29 (21) Application number: 81901995.0 (22) Date of filing: 29.06.1981

(51) International Patent Classification (IPC):  H01J 61/ 04( . ) H01J 17/ 04( . ) H01J 11/ 02( . ) (86) International application number: PCT/US1981/000894 (87) International publication number: WO 1982/000220 (21.01.1982 Gazette 1982/03)

(84) Designated Contracting States: DE GB NL (30) Priority: 30.06.1980 US 19800164853 (71) Applicant: NCR CORPORATION Dayton, Ohio 45479 (US)	(72) Inventor: HALL, Stacy Wilmot Colorado Springs, CO 80907 (US) (74) Representative: Robinson, Robert George  International Patent Department NCR Limited 206 Marylebone Road London NW1 6LY London NW1 6LY (GB)