GB2206311A

GB2206311A - Rotary printing machine liquid transfer units

Info

Publication number: GB2206311A
Application number: GB08813941A
Authority: GB
Inventors: Rudi Junghans
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 1987-06-16
Filing date: 1988-06-13
Publication date: 1989-01-05
Anticipated expiration: 2008-06-13
Also published as: FR2616709A1; CH677901A5; DE3720053A1; FR2616709B1; GB8813941D0; GB2206311B; DE3720053C2

Description

22063 11 ROTARY PRINTING MACHINE FLUID TRANSFER UNITS The present

invention relates, in a first aspect thereof, to a rotary printing machine inking unit which utilises an inkliountain, and an ink fountain roller for metering the amount of ink to be transferred to the inking unit rollers, a vibrator roller being provided which (in use) executes an oscillating movement between the ink tountain roller and a first inking unit roller, whereby (in use) an ink stripe is transferred from the ink fountain roller on to the first inking unit roller.

A known construction of this type is described in German Laid Open Patent Application (Offenlegungsschrift) No.2553177. The latter shows a metering system in which the profile of the vibrator roller is grooved, in order to prevent the liquid from accumulating during the times at which the vibrator roller is engaging the ink fountain roller. By reducing the outer cylindrical surface of the vibrator roller to about a half, it is possible not only to avoid the formation of a bulge in the cylinder nip, but also to reduce the noise made when the vibrator roller is brought into and out of contact with the ink fountain roller and the first distributor roller, and additionally to decrease the load with which the drive has to contend. It is a disadvantage of this known construction, however, that the times of contact of the vibrator roller and the stepwise shifted ink fountain roller have to be made undesirably lopg in order to convey the required amount of ink into the inking unit. Furthermore, 4 these prolonged contact times entail shortened reversal times for the vibrator roller, which adversely affects the dynamic properties or running characteristics of the inking unit.

Setting out from this state of the art, it is an object of the present invention to make it possible to optimize a metering system such as has been discussed, in the sense that the.transfer of maximum ink amounts shall not involve any constructional changes at the inking unit and that even ink amounts differing very greatly over the length of the roller shall be capable of being transferred without any difficulty.

According to the present invention, there is provided a rotary printing machine inking unit which utilises an ink fountain, and an ink fountain roller for metering the amount of ink to be transferred to the inking unit rollers, a vibrator roller being provided which (in use) executes an oscillating movement between the ink fountain roller and a first inking unit roller, whereby (in use) an ink stripe is transferred from the ink fountain roller on to the first inking unit roller, the first inking unit roller rotating at machine speed and the ink fountain roller being driven at a substantially lower speed of rotation, and the vibrator roller having a jacket made of elastic material whose outer cylindrical surface is provided with grooves which are substantially uniformly distributed and which are 0.1 to 0.3 mm deep.

It the amount of ink to be transferred with such a vibrator roller is very small, the ink is transferred only by the ridges intervening between the grooves; thus, by reducing the outer cylindrical 4 I surface of the vibrator roller, the amount of ink which is transferred is also reduced, e.g. to about half. It, however, a greater amount, e.g. a maximum amount, of ink is to be transferred to the inking unit, then additionally the grooves, with their above-mentioned 0.1 to 0.3 mm depths, will transfer ink to the first inking unit roller, so that the vibrator roller employed in the present case has the same eftect as a vibrator roller whose outer cylindrical surface is ungrooved. Within the range within which one can adjust between minimum and maximum ink supply, the transition is stepless, so that it is not necessary for the contact times to be considerably extended.

The fact that the present vibrator roller can ensure a uniform ink transfer even with an ink supply which varies very greatly, along the length of the vibrator roller, constitutes a further particularly important advantage. Thus, if, for instance, a maximum amount of ink had to be supplied to the middle region of the vibrator roller, and only minimum amounts had to be supplied to its outer regions, the use of a vibrator roller with an ungrooved outer cylindrical surface would be liable to produce an accumulation of ink in the middle region, which would tend to urge the vibrator roller, at greater speeds of rotation, away from the first inking unit roller, for example. This, in turn, by reason of the alteration in the distance between the two rollers, has the effect that the ink being transterred is reduced in the outer regions requiring minimum ink supply.

Where a maximum ink supply is needed, a prior-art roller having a grooved profile requires a 4 4 - prolonged contact time, so that the outer regions needing (in the instance just mentioned) only a minimum of ink are liable to be supplied with too much ink, i.e. with ink which is not needed. The vibrator roller employed in accordance with the invention, in contrast, makes it possible, without causing ink accumulation, to have ink transferred additionally by the grooves to the middle region which requires a maximum ink supply; thus enough ink is made available. In the outer regions, the ink is transferred only by the ridges intervening between the grooves, so that the desired minimum supply of ink is ensured. It is important that the grooves should be only some few tenths of a millimeter deep; in tests, a range of 0.1 to 0.3 mm proved to be the optimum.

According to preferred or optional features of the invention. the abovementioned grooves may be arranged on the outer cylindrical surface of the vibrator roller in a spiral configuration, or again in a rhombic configuration. It is advantageous that the grooves should be cut into the outer cylindrical surface of the vibrator roller, and that the widths of the grooves should be equal to the widths of the intervening ridges, being preferably 7 to 9 mm, e.g. 8 mm. It will be appreciated that the dimensional accuracy of the grooves provided in the cylinder jacket made of elastic material should desirably match that of the outer cylindrical surface of the vibrator roller itself.

In addition to relating to an inking unit as already described, the invention relates, in a second aspect thereof,,to a rotary printing machine damping unit, this being a unit wherein a damping medium z 4 1 transferring roller is employed which has a jacket as specified in respect of the present inking unit.

one embodiment of the invention is represented in the accompanying diagrammatic drawings, in which:

Figure 1 is a side view showing a rotary printing machine inking unit according to the invention, Figure 2 shows the vibrator roller of the unit of Figure 1, from the side. and Figure 3 is a fragmentary axial section, on an enlarged scale, of the vibrator roller of Figure 2.

With the inking unit shown in Figure 1, a plate cylinder 1 is inked by means of a plurality of inking unit rollers 2, the ink being transferred in metered amounts from an ink fountain 3 and an ink fountain roller 4, to a first inking unit roller 6, by means of a vibrator-roller 5. The vibrator roller 5 employed here is pivot-mounted in a known manner on an axle 8 b y means of levers 7 provided at both ends of the axle 8, and is so driven that, for predetermined times, sid vibrator roller is engaging the ink fountain roller 4, and, for certain other predetermined times, it is engaging the roller 6. The roller 6 and the subsequent inking unit rollers 2 rotate at the same circumferential speed as the plate cylinder 1, whereas the ink fountain roller 4 is driven at a considerably lower speed. The circumferential speed of the ink fountain roller 4 is adjustable, however, with respect to the circumferential speed of the inking unit rollers.

The vibrator roller 5, as shown in Figure 2, is mounted in the levers 7 by means of journals 9 provided at both ends of the axle. As 'Figure 3 shows, an elastic but highly wear-resistant coating 11 4 has been applied to a tubular jacket 10 carried by the vibrator roller 5. The outer cylindrical surface of the vibrator roller 5, i.e. of the elastic coating 11, is provided with grooves 12, which are preferably cut in. The depth a of the grooves 12, with respect to the intervening ridges 13, is of the order of 0.1 to 0.3 mm. The ridges 13 and grooves 12, which together form the outer cylindrical surface of the vibrator roller 5, may have a spiral configuration, as shown in Figure 2. It is also possible for the outer cylindrical surface to have a rhombic configuration. This may be obtained by providing not one but two spiral formations, which wind in opposite directions. A ridge 13 is preferably 8 mm wide, and also is preterably just as wide as a groove 12, so that the sum of all of the ridges 13 represents only half of the total outer cylindrical surface of the vibrator roller 5.

The present vibrator roller may also be used, without any modification, in a damping unit.

It will be understood that the invention has been described above purely by way of example, and that various modifications of detail can be made within the ambit of the invention.

A 1 R E F E R E N C E 1 1 2 3 4 5 6 7 8 9 10 11 12 13 plate cytinder inking unit rollers ink fountain ink fountain roller vibrator roller roller lever a x 1 e axle journal j a c k e t coating groove ridge N U M B E R S 0

Claims

1. A rotary printing machine inking unit which utilises an ink fountain, and an ink fountain roller for metering the amount of ink to be transferred to the inking unit rollers, a vibrator roller being provided which (in use) executes an oscillating movement between the ink fountain roller and a first inking unit roller, whereby (in use) an ink stripe is transferred from the ink fountain roller on to the first inking unit roller, the first inking unit roller rotating at machine speed and the ink fountain roller being driven at a substantially lower speed of rotation, and the vibrator roller having a jacket made of elastic material whose outer cylindrical surface is provided with grooves which are substantially uniformly distributed and which are 0.1 to 0.3 mm deep.

2. A unit according to claim 1, wherein the grooves are arranged on the outer cylindrical surface of the vibrator roller in a spiral configuration.

3. A unit according to claim 1, wherein the grooves are arranged on the outer cylindrical surface of the vibrator roller in a rhombic configuration.

4. A unit according to claim 1 or 2, wherein the grooves are cut into the outer cylindrical surface of the vibrator roller, and wherein the widths of these grooves are equal to the widths of the intervening ridges.

5. A unit according to claim 4, wherein the said widths are 7 to 9 mm.

6. A unit according to claim 1, substantially as described with reference to the accompanying drawings.

7. A rotary printing machine damping unit wherein a damping medium transferring roller is employed which has a jacket as specified in respect of the vibrator roller in any of claims 1 to 5 or substantially as described with reference to Figures 2 and 3 of the accompanying drawings.

Published 1988 at The Patent Office, State House 66 71 High Holborn. London WC1R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1.87.