US 3345943 A
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Oct. 10, 1967 Filed Aug. 17. 1965 J. A. RAKOWICZ ETAL INKING DEVICES FOR PRINTERS 2 Sheets-Sheet l Oct- 10, 196 I J. A. RAKOWICZ ETAL 3,3 3
INKING DEVICES FOR PRINTERS Filed Aug. 17; 1965 v 2 Sheets-Sheet 2 fie. Z.
United States Patent 3,345,943 INKING DEVICES FOR PRINTERS Jan Antoni Rakowicz and Geotfrey Arnold Wark, London, England, assignors to The Molins Organisation Limited, London, England, a corporation of Great Britain Filed Aug. 17, 1965, Ser. No. 480,302 Claims priority, application Great Britain, Sept. 1, 1964,
35,783/64' 3 Claims. (CI. 101--366) ABSTRACT OF THE DISCLOSURE This invention relates to a device for feeding ink at a metered rate to a pair of inking rollers in a letterpress printer. The device comprises a piston-cylinder arrangement with a nozzle for directing ink to the nip between the rollers, the piston being driven by the intermittent rotation of a screw member which itself is driven by a sprag clutch and lever arrangement, thelever being driven by the letterpress printer. Means is provided for adjusting the effective length of the lever to regulate the amount of rotation of the sprag clutch with each stroke. Also means is provided for conveniently resetting the means for driving the piston when the supply of ink has been exhausted from-thecylinder and is being refilled.
This invention concerns improvements in inking devices for printers and has among its objects to provide a device which can operate at a high speed without the risk of ink splashing and arranged to meter the ink, so that very fine printing can be achieved with uniform colour and density.
According to the invention an inking device for a letterpress printer comprises a pair of inking rollers running in contact and a fine nozzle arranged to fit in the nip of the two rollers so that a tiny wedge of ink is contained between the rollers and the nozzle, with means for feeding ink through the nozzle at a metered rate, depending upon the desired rate of consumption.
The nozzle may form part of a syringe, with means for feeding the piston of the syringe at the desired rate and the body of the syringe may be insulated so as to preserve the viscosity of the ink at the desired value, in spite of any changes in ambient temperature.
The nozzle referred to above may be the kind of nozzle used in hypodermic syringes and the syringe itself may be a hypodermic, with a capacity suitable for providing ink for any desired period of time. The piston may be pushed through the cylinder of the syringe by power driven means such as gearing driven by a variable speed electric motor, or by mechanism coupled to some other part of the printing machine.
The piston movement may be continuous or intermittent and examples of both arrangements are given later.
The invention will be more fully described with reference to the accompanying drawings, in which:
FIGURE 1 is an elevation, partly in section, of a portion of a printing machine embodying the invention;
FIGURE 2 is an elevationof part of a printing machine in which the ink-feeding arrangements differ somewhat from those shown in FIGURE 1;
FIGURE 3 is a view of a fragment of FIGURE 2 looking in the direction of the arrow A, part of the frame of the machine being in section; and
FIGURE 4 is an end elevation of FIGURE 3.
Referring first to FIGURE 1, 1 is a web which is to be printed and it is guided by a pair of rollers 2, one of which runs near a letterpress die 3 which, as shown, has four printing surfaces 4 on it. The printing surfaces receive ink from a small roller 5 and this in turn reice ceives ink from a large distributing roller 6, which re-- ciprocates on its shaft with distributors 7 operating on parts of its circumference. Beneath the roller 6 is another roller 17 and these two run in close contact and in the nip of the rollers there is arranged a nozzle '8, which may be the nozzle of a hypodermic syringe, or some small nozzle suitable to enter between the nip of the rollers, and arranged vertually in contact with them. In fact there is a small clearance to avoid wear on the syringe nozzle and to clear the ink layer. The nozzle forms part of a syringe 9 which has a piston 10 having a piston rod 11 with a spring 12 tending to withdraw the piston from the neighbourhood of the nozzle. The syringe body is clamped in position as shown.
The piston rod 11 is engaged by a finely threaded screw 13 which works in an axially fixed nut consisting of a gear wheel 14 and this is rotated to feed the screw and drive the piston forward by means of a gear wheel 15 driven by a variable speed motor 16. The screw is prevented from rotating by a spline or the like not shown.
In operation the speed of the motor is adjusted so that the quantity of ink fed through the nozzle is exactly that required to provide adequate ink to the four printing surfaces of the roller 3 and the location of the nozzle is such that between the rollers 6 and 17 there is a tiny wedge of ink which cannot escape, since it is in a virtually closed compartment and thus there is no risk of ink splashing. The ink fed through the nozzle to the roller 6 is distributed over the roller 6 by the distributors 7 and a thin film of ink is provided to the transfer roller 5 and applied to the printing surfaces of the roller 3. If desired the rollers 7 may be reciprocated axially to distribute the ink on roller 6 which then has no axial movement.
As shown, the syringe is large enough to contain a quantity of ink suitable for a run of a desired time, say several days, and the body may be surrounded by suitable lagging so as to keep the temperature within the interior of the syringe at a uniform level and retain the viscosity of the ink at a desired value.
It will be seen that in this example the piston 10 is moved continuously.
Referring now to FIGURE 2, the ink is fed as before through a nozzle 18, into the nip of a roller 19 and a larger roller 20. A distributor roller 21 which reciprocates axially spreads the ink on the roller 20.
Ink on roller 20 is transferred to a further roller 25 which applies the ink to the letterpress die roller 26 which has printing surfaces 27 on it. The roller 25 is supported on a quadrant-shaped plate 22, pivoted on the shaft of roller 20 and adjustable on the pivot by a screw 24. In this way the roller 25 can be moved to adjust its pressure against the printing surfaces 27.
The paper web 28 passes around rollers 29, 30 and 31, the roller 30 being carried on a lever 30A, pivoted at 32 and adjustable on the pivot by a screw 33 and spring 34. In this way the web can be brought into the desired contact with the printing surfaces 27 Ink is fed through the nozzle 18 by a piston 35, fixed to a piston rod 36, and movable in the body of a syringe 37, the movement being effected by a screw 38 which has a nut 39 on it arranged to press on the end of the piston rod. The screw is rotated intermittently by a connecting rod 40 driven by a crank disc 41 which is r0- tated from the machine driving mechanism by a shaft 42 driven through bevel gear wheels 43 one of which is fixed to a shaft 44, driven by said mechanism. The end of the connecting rod 40 remote from the crank disc is adjustably connected to a lever 45 which drives a sprag clutch 46, to the driven member of which the screw 38 is fixed. The lever 45 has a nut 47 slidable in a slot 48 of the lever and the position of the nut can be altered by a screw 49, thus altering the throw of the sprag clutch and the amount of rotation of the screw for each revolution of the crank disc 41.
In order to avoid the necessity of winding the nut 39 back along the screw 38 when it reaches the end of the thread, the nut has two holes in it which intersect. One hole 50 is tapped to suit the thread of the screw 38 and the other 51 is a clearance hole. By rocking the nut the clearance hole may be aligned with the screw and the nut can then be slid back to the starting position.
This arrangement therefore provides an adjustable intermittent feed of the ink.
If desired a temperature controller of any known kind may be provided for controlling the viscosity of the ink in the syringe and in either construction the mechanism for moving this piston may be controlled by a device which scans the printed web and regulates the ink flow as necessary to keep the print to a desired density.
It will be seen that the ink supply is dust proof and the arrangements shown are suitable for use with a variety of inks with differing viscosities.
Because the ink supply is virtually closed against evaporation there is no change in the colour of the ink, which can occur When a solvent evaporates from an open ink vessel.
While the invention has been described as applied to the feeding of ink for printing it can be used for feeding adhesives where the accurate application of desired quantities of adhesive is necessary.
Alternatively any other suitable means may be provided for feeding ink to the nozzle, for example a pump such as is used for feeding fuel to some I.C. engines.
The above description has dealt mainly with a small nozzle such as is used in a hypodermic syringe and this is adequate for such work as printing cigarette webs where a line of small type is all that is required but for wider work a series of such nozzles may be used, side by side, or a nozzle of the width required to go into the nip of the inking rollers and extending lengthwise of the rollers for the distance required may be used.
What we claim as our invention and desire to secure by Letters Patent is:
1. An inking device for a letterpress printer comprising a pair of inking rollers mounted for running in contact with each other, a piston-cylinder arrangement for containing and feeding an ink supply, a fine nozzle arranged to fit in the nip of the two rollers, conduit means connecting said cylinder with said nozzle, and power driven means operatively connected to said piston to move said piston through said cylinder for feeding ink at a metered rate from said cylinder through said nozzle to maintain a small wedge of ink in said nip, said power driven means comprising a crank device operatively connected to and driven by said letterpress printer, a rod secured to said piston, an axially fixed screw having a nut thereon which presses against said rod whereby rotation of said screw causes said nut, rod and piston to move, a sprag clutch secured to said screw, a lever for driving said clutch and a connecting rod secured to said lever and operatively connected to said letterpress printer whereby said screw is intermittently rotatable.
2. An inking device as claimed in claim 1 further comprising means for altering the throw of said sprag clutch, said means comprising a slot in said lever, a second nut in said slot and secured to said connecting rod, a manually rotatable screw operatively connected to said second nut, whereby adjustment of said screw and resultant adjustment of said second nut regulates the effective length of said lever and its angular movement with each stroke of the connecting rod.
3. An inking device as claimed in claim 1 in which the nut on the axially fixed screw has a threaded hole to engage the screw and a plain hole intersecting the threaded hole whereby the nut may be rocked on the screw to move the threaded hole out of engagement with the screw and align the plain hole therewith so that the nut may be slid back along the screw when it reaches the end of its advancing movement on the screw.
References Cited UNITED STATES PATENTS 2,312,140 6/1943 Grupe 1012l9 2,676,563 4/ 1954 Montgomery et al. l18249 X 3,199,451 8/1965 Nitchie 101366 ROBERT E. PULFREY, Primary Examiner.
F. A. WINANS, Assistant Examiner.
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