GB1438655A - Photographic copying apparatus - Google Patents

Abstract

1438655 Contact printing apparatus R A ROOSEN 18 June 1973 [10 Aug 1972] 37453/72 Heading G2A A photographic copying apparatus comprises a housing 1 in which there is a holder 2 for a strip of light-sensitive recording material 3, a light source 4, a strip driving means including at least one rotatable element which can be rotated by frictional contact with a surface 5 bearing matter to be copied as the apparatus is advanced over that surface and which thereby advances the strip through an exposure zone where it is irradiated by light from the source 4 and is in contact with the surface 5, and exposure control means which functions in dependence on the rotation of the rotatable element to cause emission of light pulses of predetermined energy from the source 4 at a frequency that is linearly dependent on the speed of rotation of the element, so that the number of pulses emitted during passage of a given length of the strip 3 through the exposure zone is the same for different rotation speeds. The exposure control means may comprise an actuating circuit for the light source, which circuit produces an energy pulse of a predetermined shape and magnitude (on the intensity-time scale) responsive to any activating input pulse, and a triggering circuit which delivers such an input pulse during each of successive partial rotations of the rotatable element. A group of magnetic strips may rotate with the rotatable element and the strips may cause successive closures of the triggering circuit during each revolution of the element. The exposure control means may comprise a one-step multi-vibrator which controls actuation of a switch mechanism of an energization circuit of the light source. In Fig. 8 the apparatus contains batteries 24 whereas in Fig. 1 the apparatus is connected to an external power source. The apparatus may contain a builtin processing station for processing the lightsensitive material. The apparatus is moved over the original 5 in the direction shown by the arrow 6 and photo-sensitive material 3 is fed into second channel 8 and guided on to a take-up reel 9 in Figs. 1 and 8. In Fig. 8 the light source 11 consists of a single tubular lamp in a parabolic reflector 34 provided with a slit 38 for uniformly pre-exposing the photo-sensitive material 3 to a fraction of its normal exposure value before this normal exposure occurs beneath window 12. A lid 39 is hinged by hinge 45 to housing 1, for guiding the photo-sensitive sheet 3 out of the apparatus if any small copies are to be made. The lid 39 may be provided with a cutting device.