| 摘要 |
698,674. Supply systems for discharge lamps. BRITISH TABULATING MACHINE CO., Ltd. April 17, 1950 [April 19, 1949], No. 9375/50. Drawings to Specification. Class 38 (iv). [Also in Groups XIX, XX and XL (b)] In a machine for making photographic film records of punched record cards, a fluorescent discharge lamp for exposing through cardcontrolled shutters a continuously moving photographic film is fed from a multivibrator so that the discharge frequency is sufficiently raised to avoid striations appearing across the width of the exposed and developed film record, which comprises a dark ground having clear spots in positions corresponding to the card perforations.
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