| 摘要 |
494,876. Photographic contact-printing apparatus. QUARZLAMPEN GES. Feb. 25, 1938, No. 5978. Convention date, Feb. 27, 1937. [Class 98 (ii)] Apparatus for producing photographic prints comprises a transparent half-cylinder 1 arranged with its two horizontal longitudinal edges vertically one above the other. An extended source of light 2 is arranged along the axis, and the matter to be copied and the sensitive paper are pressed against the cylinder by a cloth 3. The light source 2 may be a high pressure mercury lamp with solid activated electrodes. The resistance 4 and other parts required for the lamp are housed in a chamber 6 which, with the side walls and the halfcylinder 1 forms a unit. Caps are provided to protect the ends of the lamp, and ventilation is effected by slots 9, 10. The cloth 3 carries a rod 11 provided with hooks by which it may be stretched and secured to the casing. The cloth 3 rests on a plate 15 to receive the copying materials. The cloth may be opaque or blackened, with an aperture or transparent part, or an apertured screen, to observe the print. A rotating shutter 17 acting also as a reflector, is provided, and may be'driven by clockwork. A switch may be provided by which an additional resistance may be placed in series with the lamp when required, whereby it burns as a low pressure arc and its intensity is reduced. Alternatively, the mains voltage may be reduced by a transformer. The length of the cloth 3 may be adjusted by a resilient sleeve 25, Fig. 4, slipped over the rod 14.
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