Patent GB-768977-A (GB)
Title: A method of and apparatus for moistening paper to be printed in hectographic duplicating
IPC: B41L7/08
Filed: 1955-05-04
Abstract: 768,977. Duplicating-machines. RENA BUROMASCHINEN FABRIK GES. May 4, 1955 [May 22, 1954], No. 12887/55. Class 100(2) In hectographic duplicating machines, the sheets to be printed are moistened by spraying the liquid on to the paper as a thin film by means of compressed air. The spraying head may be fixed and the sheets moving during the spraying operation, or the head may oscillate above a stationary sheet. One form of oscillating head 1, Fig. 3 comprises upper and lower parts 5, 6, fixed together. Within the upper part 5 is a conical seating 13 separating two chambers 11, 12 and normally engaged by the conical end of a sleeve 17 pressed downwardly by a spring 20 bearing at its upper end against a packing washer 18 held in place by a threaded bush 19 through which the sleeve passes. A source of compressed air is connected to a pipe 15 leading to the chamber 11. Within the sleeve 17 is slidably mounted a needle 16 which passes through a packing 21 in the part 6 and is.urged downwardly by a spring 24 so that its pointed end 25 closes a nozzle 8 in a member 7 fixed to the lower end of part 6. A source of moistening liquid is connected to a pipe 28 communicating by means of a passage 26 with a space above the nozzle 8. Attached to the lower end of the part 6 is a member 9 surrounding and spaced from the member 7, a member 10 attached to member 9 has nozzles 33, 34 and an opening 32 surrounding the nozzle 8, the opening 32 and nozzles 33, 34 communicating with the chamber 12 through passages 30, 31 in the part 6. A nut 35 on the upper end of the needle 16 is adjacent to a collar 36 on the sleeve 17, there being a small clearance between them when the sleeve and needle are in their lowermost positions. A lever 37 has a forked end engaging beneath the collar 36, and a stop 39 engaging a link 41 carrying a roller 42 which engages an arcuate track 43 during rocking of the head about its pivot 4; a spring- controlled lever 45 connected by a link 46 to the duplicating machine causes the rocking. Starting from a position anticlockwise of that shown, the head 1 moves clockwise. As it does so, the roller 42 engages the track 43 and operates the lever 37 so that in sequence (a) the sleeve 17 is raised and compressed air admitted to the nozzles 33, 34 and opening 32 (b) the needle 16 is raised to admit moistening liquid to the nozzle 8 (c) the needle is lowered to cut off the moistening liquid and (d) the sleeve 17 is lowered to cut off the compressed air. During the return movement of the head 1, the link 41 is moved upwardly and idly about its pivot 40 without actuating the lever 37 so that no discharge of air or liquid occurs. A modified form of rocking head, Figs. 4 and 5, comprises a casing 60 with an inner fixed sleeve 61 and a relatively rotatable member 50 therein. One pivot bore 71 is provided in a member 70 closing one end of the casing 60 and another pivot bore 51 in the end of the member 50, the members 60 and 50 being rotatable relatively or together about pivots engaging the bores. Two central bores 52, 56 are formed in the part 50 which are connected by passages 54, 55 and a passage 57 respectively to the outside surface of the member 50. in the sleeve 61 is an annular passage 62 with a radial passage 76, and also a longitudinal passage 63 opening at one end to a space 68 between the parts 50, 70. The casing 60 has connections 64, 65 for compressed air and moistening liquid respectively, the radial bores 66, 67 of which extend through the sleeve 61. Nozzles 77, 78 and a nozzle opening 75 pass through the casing and connect with the annular passage 62. A lever 59 connected to the member 50 has a bent end engaging a recess in a disc 74 attached to the casing, the lever normally being caused by a spring 83 to engage an abutment 85 on the disc. A spring-pressed roller 81 engages a recess 82 in the disc to hold it yieldingly in the initial position shown in Fig. 5. An operating lever similar to the lever 45, Fig. 3, is connected at 84 to the lever 59. In operation, the lever 59 is first moved clockwise with the member 50, the casing 60 remaining stationary. This causes in sequence (a) passages 57, 66 to begin to register so that pressure air passes to the nozzle openings 75, 77, 78 via passages 56, 68, 63 and 62 (b) the,passages 54, 67 and 55, 76 begin to come into alignment to permit the passage of moistening liquid to the nozzle opening 75 where it is entrained by the compressed air and sprayed on to the paper. At this stage, the lever 59 engages another shoulder 86 on the disc 74. Further movement of the operating lever now causes the parts 56, 60 to move clockwise together, and spraying with compressed air and liquid continues. During such further movement, the roller 81 is forced out of the recess 82, and the movement continues until the point 88 of the disc 74 reaches the roller 81, when the operating rod ceases to turn the member 50 clockwise. The engagement of the roller 81 with an inclined surface 89 on the disc 74 causes the casing 60 to be rotated clockwise while the member 50 is stationary, the movement being sufficient to rotate the parts to their original relative positions, Fig. 5, with the moisture and air supplies cut off in that order; the head is however displaced clockwise relatively to the position shown in Fig. 5, and is now returned by spring means prior to the commÚncement of the next cycle of operations.