US3008408A - Inking mechanisms for printing machines - Google Patents

Description

Nov. 14, 1961 I. P. KNOPS ETAL INKING MECHANISMS FOR PRINTING MACHINES Filed March 18, 1960 2 Sheets-Sheet 1 Nov. 14, 1961 KNOPS ET 3,008,408

mxmc MECHANISMS FOR PRINTING MACHINES Filed March 18, 1960 2 Sheets-Sheet 2 United States Patent O 3,008,408 INKING MECHANISMS FOR PRINTING MACIMES Ivan Peter Knops, Twickenham, and Peter Henry New:

man, Kew Gardens, England, assignors to Thomas De The present invention relates to improvements in inking mechanisms and a method for applying an even ink film to a printing plate and is especially applicable to intaglio machines including at least two sequentially arranged inking rollers andwherein a high inking pressure is required.

It is common practice to transfer an ink film from an inking system to the surface of a printing plate by means of an oscillating resilient transfer roller that alternately contacts the surfaces of the plate cylinder and the ink distribution roller. This method, however, suffers from the disadvantages that line effects and uneven film thickness are created at the point of separation between the distribution and transfer rollers whilst rolller skid occurs when a freely running ink transfer roller contacts the printing plate owing to variations in peripheral velocities.

Methods have been evolved to drivethe oscillating transfer roller at a synchronous surface speed to that of the plate cylinder by means of. gearing systems so that, during the period of travel between the contacting surfaces, it is constantly driven at the correct speed. However, problems arise when a transfer roller has to be changed and may necessitate respective alterations in gear ratios. Also inaccuracies will be unavoidable when the surface has to be retrued, through uneven wear, owing to a slight reduction in overall diameter.

It is advantageous both to apply theoscillating ink transfer roller to the plate cylinder surface under considerable pressure to ensure that the intagliated depressions are fully inked and also to provide forms of adjustment to enable a predetermined pressure to be instantly selected, between the plate surface and the transfer roller and the transfer roller and the distribution roller.

One object of the invention is to overcome the disadvantageous line effects and roller skid phenomena by arranging that the distribution and transfer rollers remain in constant contact with one another throughout the period of oscillation of the transfer roller. This method thereby overcomes the line effects by providing a continuous transfer of link. Roller skid is overcome by the fact that the distribution roller is geared in synchronism with the plate surface and thus the transfer roller Will always be frictionally driven at the same speed.

A further object of the invention is toprovide a high plate inking pressure from the transfer roller by means of a linkage system incorporating pairs of toggle plates to give an increasing thrusting force when the link members are approaching alignment, thereby relieving. the actuating mechanism of excess stress.

A further object of the invention is to provide a system of calibrated adjustments between the coacting surfaces that will enable an operator rapidly to set the inking mechanism to predetermined loadings.

According to this invention, an inking system for a printing machine comp-rises a transfer roller which is adapted intermittently to co-act with a printing plate and be frictionally driven by an ink distribution roller across the periphery of which said transfer roller oscillates in an arcuate manner and in continuous contact with said distribution roller.

Preferably the printing plate and its associated ink ice transfer roller are driven, whilst in contact, at equal peripheral speeds. p i

Preferably the ink transfer roller is caused to oscillate by a mechanical system which provides-a high thrusting force between the ink distribution roller and the printing plate.

Preferably in a rotary printing machine the ink transfer roller is caused to oscillate through the medium of a toggle linkage system operated from a cam track arranged on the plate cylinder in accordance with the position of the printing plates.

Preferably adjustment means may be provided to adjust the contact pressure between the ink distribution and transfer rollers on the one hand, and on the other hand between the ink transfer roller and the plate surface.

Preferably the adjustment means consists on the one hand of a screw operated slidable member and on the other an eccentric bearing both of which are suitably calibrated to enable the apparatus to be readily set to a predetermined loading.

One embodiment of the invention will now be described by reference to the accompanying drawings of which FIGURE 1 is a fragmental view of the plate cylinder and part of the inking system of a rotary printing machine and; FIGURES 2 and 3 depict diagrammatically two extreme positions of certain movable components of the inking system.

It should be noted that with the exception of the driving gears the mechanism is symmetrical about the cent-reline of the machine and, therefore, the description will refer to one sideonly.

Referring to FIGURE 1, a plate cylinder 1 rigidly mounted on a shaft 2 carries a printing plate 3 bearing a number of engraved designs 4. A gear wheel 5, which forms part of the main drive of the machine, is rigidly mounted on the shaft 2 together with a cam-track which comprises a rise section 6, a constant radius lift segment 7, a fall section 8 and a constant radius dwell segment 9, the gear wheel 5 and the cam track both being fast with the plate cylinder 1.

A steel ink distribution roller 10 and an ink transfer roller 11, which is covered with a resilient material, form part of. the inking system of the machine and roller 10 is adapted to be inked in the manner described below. Roller 10 is mounted on a shaft 12 and is rigidly connected to a gear wheel 13. The gear wheel 13 is arranged to mesh with an idler gear 14 freely mounted on a shaft 15 and arranged to mesh with the gear Wheel 5. The gear ratios are selected to provide the plate cylinder 1 and the distribution roller 10 with identical peripheral velocities. The roller 11 is mounted on a shaft 16. g

A T-shaped lever including integral arms 17, 18 and 19 is adapted to pivot about a point 20 by means of a spigot (not shown) in the main frame. Lever arm 17 carries a freely running roller follower 21 adapted to co-act with the sections 6, 7, 8 and 9 of the cam-track. Lever arm 18 is connected at its extremity to a screwed peg 22 in the main frame by means of a coil spring 23. Lever arm 19 is connected at its extremity with a rod 2-4 which atits other end is joined to a pair of toggle plates 25 and 26 by means of a pin 27. A link member 28 mounted on a sub-frame of the machine by means of an eccentric spindle 29 is also connected to the toggle plates 25 and 26 by means of a pin 30. One end of the spindle 29 carries 'a rigidly mounted lever 31fitted with a handle 32 and a spring loaded plunger 33 which is adapted to engage in one of a number of calibrated depressions (not shown) provided in the sub-frame. The opposite ends of the toggle plates 25 and 26 are connected by means of a pin 34 to a member 35 which is adapted to pivot about the longitudinal axis of the shaft 12 by means of a roller bearing 36. A slidable 3 carriage 37 mounted on a plane surface of the member 35 includes a split bearing 38, the upper half of which is hinged at 39 and in which is journalled the shaft '16. A screw 40 adapted to be moved by means of a calibrated handle 41 is provided to adjust the position of the carriage 37.

In FIGURES 2 and 3 items referred to in conjunction with FIGURE 1 bear identical numerals and are illustrated in thick lines. The items shown in chain lines are incidental to, but will assist in a full understanding of, the invention. An inking-unit frame 42, capable of being retracted, is shown locked in its operative position. Within the frame are mounted an ink-duct 43, a steel duct roller 44 driven independently of the main drive to the machine, a steel primary distribution roller 45, a rubber covered oscillating transfer roller 46 adapted to oscillate between the rollers 44 and 45 and a pair of resilient selfaligning rubber covered rollers 47 and 48 inserted one.

between each waist of the rollers 10 and 45.

When the machine is working the plate cylinder 1 is driven in the direction indicated by the arrow by a prime mover through the medium of the gear Wheel which transmits motion through the idler gear 14 to the gear wheel 13 so that roller rotates in the same direction as the plate cylinder and at the same peripheral velocity. The roller 45 is driven frictionally at the peripheral speed of the plate cylinder 1 by the roller 1% by way of the rollers 4-7 and 48. Ink is fed from the duct 43 by the independently driven duct roller 44 and is transferred to the roller 45 by means of the roller 46 which oscillates between rollers 44 and 45 in accordance with motion transmitted thereto from a linkage system operated by mechanism which controls the movement of the impression cylinder of the machine.

As the plate cylinder rotates, the roller follower 21 rides on the cam-track 6, 7, ti and 9 and when it is in contact with the constant radius lift section 7 the T-shaped lever pivots at point 20 in such a way that tension is applied to the spring 23 and that, through reciprocation of the rod 24, the toggle links 25, 26 and 28 move so that bearing pins 29, 30 and 34 are substantially in a straight line. The movement of the links 25, 26 and 28 causes the member 35 to pivot on the shaft 12 so that the roller 11 is forced into contact with the printing plate 3. The arrangement is such that the roller 11 contacts the plate surface just before alignment of the pins 29, 30 and 34 so that, when alignment is completed, a high thrusting force is applied to the plate, thereby ensuring that the engravings on the plate are completely inked. The cam-track is of such length and phase that the roller 11 contacts the printing plate for a desired period of time. This inking position of the machine is shown in FIGURE 2.

When the roller follower 21 leaves the constant radius lift section 7, the T-shaped lever pivots at point 20 under the action of the spring 23, and, through corresponding movement of the rod 24, causes the links 25, 26 and 28 to pivot the member 35, on the shaft 12, in such a way that the transfer roller 1'1 moves away from the printing plate 3. This position of the machine is shown in FIGURE 3. a

As the plate cylinder continues to revolve, the roller 11 is intermittently travelling between the extreme positions shown in FIGURES 2 and 3. It will be appreciated that roller 11 is always in contact with the roller 10 in that the roller 11 oscillates in an arcuate path across the periphery of the roller 10 at the same time as it is driven by it. This eliminates the disadvantageous line effects which are liable to occur as in known arrangements when a transfer roller oscillates between a plate cylinder and a distribution roller. In addition this invention avoids roller skid effects occurring on the printing plate, because the rollers 45, 10 and 11 are, when in inking contact, driven with surface velocities equal to that of the plate cylinder.

In the illustrated example of the invention the two methods of adjustment comprise the screw mechanism operated by the calibrated handle 41 to move the carriage 37 along the plane surface of the member 35, which effectively alters the distance between the bearing centres and also in consequence the pressure between the rollers 10 and 11, and also the eccentric pin that adjusts the fixed anchorage point of the toggle system and accordingly varies the limit of displacement of the oscillating transfer roller and itscontacting pressure against the plate surface. It should be noted that a line AB parallel to the plane surface forming the guide Way of the slidable carriage 37, is inclined at an acute angle d to a line CD connecting the centres of the distribution roller and the transfer roller 11. Therefore, adjustment of the carriage '37 will cause a proportional advancement of the transfer roller 11 towards the distribution roller 10 and the plate surface. The second adjustment of the eccentric pin '29, by the handle 32, will finally provide the desired plate inking pressure.

An alternative embodiment of the adjustment means of the invention may consist of mounting the transfer roller bearing blocks 38 within the pivoting member 35, having guideways in a direction parallel to a line joining the centres of the distribution and transfer rollers, thereby to provide adjustment of the contacting pressure. A second adjustment to the anchorage point of the toggle system is provided to permit variations to be made to the plate inking pressure.

A third alternative form of adjustment may be carried out in a similar manner by mounting the slidable blocks in guid'eways approximately at right angles to the centres of the transfer and distribution rollers thereby to allow movement substantially tangential to the latter and radial to the plate surface. In this instance an auxiliary adjustment is required, parallel to the centres of the transfer and distribution rollers, to control the ink film thickness.

What is claimed is:

l. A mechanism for inking, under high pressure, the printing plate of a rotary printing machine having a frame, said mechanism comprising an ink distribution roller; means for driving said ink distribution roller at the same surface speed as said printing plate; a pair of oscillating arm units pivoted about the axis of said distribution roller; an ink transfer rollerjournalled in said arm units and being in frictional surface contact with said distribution roller; toggle linkage means connected pivotally to each of said arm units and to said machine frame and comprising an intermediate hinge point; me chanical means connected to said intermediate hinge point for actuating said toggle linkage means; and cam means operable in response to movement of said print ing plate for actuating said mechanical means whereby the transfer roller is caused intermittently to oscillate about said distribution roller into and out of contact with said printing plate and thereby to ink said printing plate under high pressure applied through said toggle linkage means.

2. A system as claimed in claim 1 in which said arm units comprise means for adjusting the position of the ink transfer roller relatively to the axis of said distribution roller.

3. A system as claimed in claim 2 in which said adjusting means comprises carriages journalling said ink transfer roller and being mounted to slide on the arms of said arm units, and calibrated'screw means connecting said arms to said carriages.

4. A system as claimed in claim 1 comprising means for adjusting the positions of the pivotal connections of said toggle linkage means to said frame, whereby the displacement of the arm units and in consequence the contact pressure between the transfer roller and the printing plate may be varied.

5. A system as claimed in claim 4 in which said means for adjusting the positions of the pivotal connections rotatably mounted on said frame and providing the pivotal connections between said toggle linkage means and said frame, and means for locking said pins in adjusted positions.

6. An inking mechanism for a printing machine having a frame, a plate cylinder and a printing plate on said cylinder, said mechanism comprising a cam track fast with said plate cylinder; an ink distribution roller; means including a shaft on which said ink distribution roller is mounted for driving said ink distribution roller at the same peripheral speed as the surface of said plate; an arm unit pivotably mounted on said shaft; a bearing block on said arm unit; an ink transfer roller in frictional contact with said distribution roller and journalled in said bearing block; a cam follower cooperable with said cam track; a toggle linkage connected respectively to said frame and to said arm unit and having an intermediate pivot point; and a mechanical linkage joining said intermediate pivot point and said cam follower whereby said transfer roller is caused intermittently to oscillate arcuately across the surface of said distribution roller, and to ink said printing plate under the pressure applied through said toggle system and said mechanical linkage system in accordance with the movement of said cam follower on said cam track.

References Cited in the file of this patent UNITED STATES PATENTS 667,731 North Feb. 12, 1901 1,168,277 Blaine Jan. 18, 1916 1,383,945 Henderson July 5, 1921 1,396,055 Baabe Nov. 8, 1921 2,387,750 Davidson Oct. 30, 1945

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