GB586806A - Improvements in or relating to photographic copying apparatus - Google Patents

Abstract

586,806. Photographic copying apparatus. KODAK, Ltd. Oct. 24, 1944, No. 20644. Convention date, Oct. 27, 1943. [Class 98 (i)] Photographic document-copying apparatus has control member responsive to the presence of a document during the feeding movement and electrical time-lag means which is actuated by the control member and a predetermined time thereafter completes an electrical circuit to initiate the film advance in synchronism with the document feeding and/or completes an electrical circuit to illuminate the photographic field. The documents are fed by means of a pair of spaced rollers or a drum 10 past a transparent strip 11 or a masking aperture, the driving means being a motor 15 and belt and pulley system 12, 13, 14. The copying camera 16 is driven through a clutch 21, 22, a pulley 24 and a belt 25 from a pulley 26 on the end of the drum 10. The clutch is controlled by a solenoid actuated through slip-rings 28, 29 and brushes 30, 31. The documents are illuminated by lamps 32, 33 respectively below and above the document field. The control member is a rotatable rod 34 carrying fingers 35 for engaging the documents and normally contacts the drum 10, at a point above the strip 11, an arm 36 on the rod 34 operating a switch plunger 37. Identifying indicia illuminated by lamps 42 are provided on a support 38 and drum 39 and are directed on to the sensitive film by a rotating mirror 41. Electrical delayed action means for determining the correct interval between actuation of the control member and the entry of the document into the copying field may be a switch operated by electro-mechanical or heatresponsive arrangements, but is preferably an electrical condenser 43. The control circuit comprises supply lines 47, 48 connected to the motor 15, to lamps 32, 33 and 42 through their control circuits, and also through a rectifier 50 and constant voltage transformer 49 to a circuit in which the clutch 21, 22 and the condenser 43 are connected in parallel. The plunger 37 of the control member operates the arm 46 of the double-pole switch 44, 45. A master relay coil R in parallel with the condenser operates when energized, a plurality of switches R1, R2 and R3. When the document operates the control member, the switch 44 is closed and the condenser charged through the resistance 54 until the relay R is energized. Switch R1 is then closed and short-circuits the resistance 54, placing the condenser directly across the output of the rectifier, 50. When the document disengages the fingers 35 of the control member, the switch 45 is connected and the switch 44 disconnected so that the condenser discharges through a variable resistance 58 and determines the time interval before relay R is de-energized. Energization of relay R closes the relay switch R2 and causes the clutch members 21, 22 to engage and drive the sensitive film, de-energization stopping the film feed. The lamps are controlled to be dimly illuminated, except when the film is moving, by means of relay R closing switch R3 to actuate another relay X which closes relay switches X1, X2 and shortcircuits resistances 70, 80. The documentoperated switch 72 is also short-circuited so that the illuminating lamps are never extinguished whilst film is moving in the copying camera. Neon lamps 89, 93 connected across transformers 92, 66 and 96, 76 are illuminated by the unbalancing of the circuit when any of the lamps burn out.