GB166340A - Improvements in and relating to the printing of photographic cinematograph films - Google Patents

Abstract

166,340. Lawley, H. V. April 12, 1920. Printing -apparatus.-In order to control automatically the printing-light for different sections of a negative film, the negative film passes through a gate b<1>, Fig. 2, having a number of contacts e<2> and 1 to 10, and the edges of the negative film are at the commencement of the sections, provided with positioned conductive contacts d<1>, d<2>, Fig. 3, by means of which a selected circuit through the contact e<2> and one of the contacts 1 to 10 is completed to control the printing-light. The contacts in the gate are mounted on insulated strips e<1>, the contact e<2> constitutes a terminal contact, and the circuit is completed through the contacts d' and d<2> by connected runners e<4> at the back of the gate. The means for controlling the lamp circuit l, Fig. 6, comprises two series of electromagnets g, g<1>, Fig. 4, arranged in pairs, each pair having an oscillating armature g<2> pivoted on a bus-bar h<2>. Each armature has a U-contact g<3> adapted to dip into mercury cups g<4> to complete the lamp circuit l, through a variable amount of resistance k. Each of the electromagnets g has a spring armature i<1> and a contact i<2> adapted to shortcircuit the other electromagnet g<1> across a circuit p, q, r, Fig. 6. The terminal contact e<2> is connected in series with the electromagnets g<1> and the battery, and the electromagnets g are individually connected to the contacts 1 to 10 and the bus-bar h<2>. When the negative film passes through the gate and the circuit through e<2> and contact 8, for example, is completed, the No. 8 electromagnet g is energized and completes the lamp circuit through the corresponding mercury cups g<4>; the No. 8 electromagnet g<1> is short-circuited ; and the other electromagnets g<1> are all energized to prevent any other armature from being operated. When the contacts on the film have passed through the gate, contacts i, i<2> spring apart and the short-circuit q is opened, the operative armature being held by a light spring g'. When another section reaches the gate, the electromagnet g, No. 8 is energized, this light circuit is opened and another of the electromagnets g energizes corresponding to the position of the contacts d<1>, d<2> for the next section. In lieu of the contacts d', d<2>, notches or perforations may be positioned and the circuit in the gate e completed bv resilient contacts springing through the notches.