GB1564034A - Fountain roller for a dampening device for an offset printing machine - Google Patents

Description

(54) FOUNTAIN ROLLER FOR A DAMPENING DEVICE FOR AN OFFSET PRINTING MACHINE (71) We, MASCHINENFABRlK AUGS BURGNURNBERG AKTIENGESELLSCHAF a German company, of 8900 Augsburg, Stadtbachstrasse 1, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a fountain roller for a dampening device for an offset printing machine, and to such a dampening device having a roller adapted to serve as a fountain roller.

According to one aspect of the present invention there is provided a fountain roller for a dampening device for an offset printing machine, comprising a roller core and a plurality of rib members removably mounted on axially extending bearing surfaces on the core, each rib extending axially of the roller over at least a part of the roller length.

The rib members may be mounted or removed rapidly and easily. Where the rib members are of a length so as to extend over only a part of the length of the roller, they may be placed either end to end next to one another on each bearing surface and/or in the same region on several bearing surfaces around the roller core. This makes possible rapid and accurate adaption of the dampening liquid distribution both in peripheral direction and in longitudinal direction to the printing image to be printed. The problems of dampening liquid distribution which arise with a dampening device having a standard cylindrical fountain roller, may thus be avoided completely.When printing a half width paper web, for instance, the rib members on that half of the fountain roller which is not required to transfer dampening liquid can be removed, but to prevent drying out of the fountain roller, or other rollers in the dampening unit, on the "non-printing" half of the fountain roller all the rib members except one are removed. This ensures such a small distribution of dampening liquid in the non-printing zone that penetration of dampening liquid into the inking device may be avoided. At the same time a certain lifting effect of the dampening liquid is produced at the operative half of the fountain roller by reason of the rib membcrs which are separated from one another in peripheral direction.

In an advantageous development of the invention, six bearing surfaces are provided on the periphery of the roller core and therefore a maximum of six rib members may be provided. This produces, on the one hand, an approximately circular pitch in the manufacture of the bearing surfaces and on the other hand, there is, where the roller core has a relatively small diameter, still sufficient width afforded for each bearing surface. The length of the rib members may expediently be so designed that each is equal to approximately a quarter of the roller length. An adequate supply of such rib members can be provided and, because all the rib members can be constructed substantially identically, the manufacture and stock keeping of them is simple and economical.

The rib members may consist partly or wholly of rubber, for example rubber strips or beading pieces which have attachment means on the side facing the roller core. The rubber affords sufficient elasticity for the rib members and does not interfere with the liquid distribution. If necessary, rubber rib members of this type may be provided with a coating particularly amenable to dampening. In a preferred refinement of the invention. the rubber strips or beading pieces are vulcanized on to the attachment means. This ensures simple manufacture. However, gluing the rubber strips onto the attachment means, particularly with small quantity production, is also conceivable.

The attachment means may be releasably held onto the bearing surfaces by magnetism; for example permanent magnets may be provided as the attachment means. This ensures rapid. easy, reliable and, moreover, maintenance-free attachment of the rib mem bers. Depending on the particular application, the rib members may be screwed on or removably mounted by means of cooperating plug or pin and socket connections. When particularly light-weight rib members are used, a burr material type fastening, i.e. a fastening of the type in which two pieces of material cling together by interengaging hooks or hooks and eyes in the manner of a clinging burr, may expediently be used.

The rib members, disposed adjacent one another may be mutually staggered in the peripheral and longitudinal directions. This advantageously produces a mutual support of the rib members disposed next to one another, with the result that the attachment means may be made particularly light and simple in construction. Furthermore, in certain circumstances, a particularly close staggering of the individual rib members may be provided, so that a particularly large amount of dampening liquid, possibly only locally, may be transferred in use of the fountain roller.

According to another aspect of the invention, there is provided a dampening device for an offset printing machine, comprising a container for dampening liquid and a roller adapted to serve as a fountain roller, the roller having plane bearing surfaces extending axially d the roller over its length and which are adapted to receive rib members releasably mounted thereon.

The invention may be carried into practice in a number of ways but certain specific embodmients will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a lateral elevation of a dampening device for an offset printing machine, incorporating a fountain roller in accordance with the invention, Figure 2 shows diagrammatically a plan view of a fountain roller in accordance with the invention, Figure 3 shows one way in which rib members are attached to a fountain roller, Figure 4 shows a further way of attaching the rib members, and Figure 5 is a plan view of a fountain roller with rib members mutually staggered in both the longitudinal and peripheral directions.

In Figure 1, there is shown a plate cylinder 1 upon which, by means of an application roller 2, a dampening liquid may be applied, the liquid being transferred by a fountain roller 3 from a dampening liquid container 4 and on to the application roller 2 via a distributor roller 5. The fountain roller 3 is provided with a speed regulated drive which is not shown in the present simplified repre sensation; regulation of the rotational speed affects the quantity of dampening liquid, e.g. water, conveyed.

The fountain roller 3 consists of a roller core 6 mounted in the machine frame, which has on its periphery axially extending plane bearing surfaces 7 on which are mounted rib members 8 which are attached releasably by suitable attachment means. Good results could be achieved in the range of normal roller diameters by providing on the periphery of the roller core 6 six bearing surfaces 7 disposed in approximately uniform circumferential distribution on the periphery. As shown in Figure 2, several rib members may 'oe disposed end to end next to one another along each bearing surface, resulting in virtually continuous ribs 9 which project from the surface of the roller core 6 in stellate manner as viewed axially of the roller.If the same amount of water is not required to be transferreel from across the entire roller length, for example because only a half-width paper web is being printed, the rib members 8 at the portion of the roller corresponding to the non-printed half may be removed quickly and simply without it being necessary, for instance, to dismantle the fountain roller 3. In order to prevent this region of the fountain or other rollers from drying out, however, it is advantageous to leave in that region one rib 9 or two rib members 8 mutually staggered in longitudinal direction on different bearing surfaces 7. With an increased water requirement the number of rib members may be increased in a simple manner.Subdivision in longitudinal direction such that four rib members 8 can be mounted to make up each complete rib 9, provides sufficient adjustability and versatility. All the rib members 8 are preferably the same length, so that simple quantityrelated production may be achieved. However, it would also be possible to keep rib members of different types in stock, for example such that some rib members 8 are long enough to extend over the entire roller length, some are approximately half as long and some are a quarter of the roller length as illustrated in Figure 2.

Rubber strips or pieces of half-round beading are used as the rib members. To affect the dampening liquid absorption conditions, these may also be provided with a special coating, a chromium layer, for instance. It is also possible, in order to achieve particularly fine adjustability, to keep a supply of rib members 8 with different surface compositions.

As will be appreciated from Figure 3, the rib members 8 may be attached particularly simply and quickly by permanent magnets 10 to the associated bearing surfaces 7 of the roller core 6. The permanent magnets 10 may take the form of simple plates on to which the rubber strips or pieces are vulcanized. Such a magnetic connection of the rib members onto the roller core may be made and released again quickly and neatly in a simple manner without recourse to further means. Other forms of connection, however, are possible, for example by means of a burr type material strip which has proved successful particularly with rib members which are particularly light-weight in construction, or by means of screws, or plug or pin and socket connections.

In Figure 4 a plug or pin and socket connection is indicated. The rubber strip or piece of the rib member 8 is glued or vulcanized on to a plate 12 which is provided with a pin 11. The pin 11 engages in an interlocking manner into a recess or slot 13 formed in the roller core 6; the interlocking engagement is achieved by a strip 14 which is held over the recess 13 by screws 15, and which has a hole in it the edges of which form an undercut for the head of the pin 11.

A number of pins and holes may be provided for each rib member and to insert and retract the pins 11 in the strip 14 the holes may be slots with larger openings disposed laterally relative to a final position of the rib member. Alternatively, the pins 11 may be oval or oblong, for instance, so that the interlocking may be achieved by rotation.

If the rib members are screwed onto the roller core 6, there may be provided in the rubber strips through-holes for insertion of the screws, which holes may be closed after the screws are inserted, by means of small plugs, for instance.

A particularly good mutual support of the removable rib members 8 on the roller core 6 may be achieved by mutually staggering the rib members in the peripheral direction and in the longitudinal direction as shown in Figure 5. Provided that the corresponding bearing surfaces extend continuously over the entire roller length, adaptation to a very large water requirement may be achieved, for instance, by appropriately increasing the lateral overlap or by arranging the rib members completely alongside each other.

WHAT WE CLAIM IS:- 1. A fountain roller for a dampening device for an offset printing machine, comprising a roller core and a plurality of rib members removably mounted on axially extending bearing surfaces on the core, each rib extending axially of the roller over at least a part of the roller length.

2. A fountain roller as claimed in claim 1, in which six circumferentially spaced rib members are provided on the roller core.

3. A fountain roller as claimed in claim 1 or claim 2, in which each rib member extends axially over approximately one quarter of the roller length.

4. A. fountain roller as claimed in any one of claims 1 to 3, in which at least the radially outer part of each rib member is made of rubber.

5. A fountain roller as claimed in claim 4, in which each rib member includes a rubber part mounted on attachment means which cooperates with a bearing surface on the roller core.

6. A fountain roller as claimed in claim 5, in which the rubber part of each rib member is vulcanized to its attachment means.

7. A fountain roller as clained in claim 5 or claim 6, in which the attachment means are releasably held onto the bearing surfaces by magnetism.

8. A fountain roller as claimed in claim 7, in which each attachment means comprises a permanent magnet 9. A fountain roller as claimed in any one of claims 1 to 4, in which the rib members are attached to the roller core by screws.

10. A fountain roller as claimed in any one of claims 1 to 6, in which the rib members and bearing surfaces are adapted so that each rib member is removably attached to the roller core by a cooperating plug or pin and socket connection.

11. A fountain roller as claimed in any one of claims 1 to 6, in which the rib memhers and bearing surfaces are adapted so that each rib member is removably attached to the roller core by a burr material type fastening.

12. A fountain roller as claimed in any one of claims 1 to 11, in which each rib member is staggered in the longitudinal direction of the roller relative to circumferentially adjacent rib members.

13. A dampening device for an offset printing machine, comprising a container for dampening liquid and a fountain roller as claimed in any one of the preceding claims.

14. A dampening device for an offset printing machine, comprising a container for dampening liquid and a roller adapted to serve as a fountain roller, the roller having plane bearing surfaces extending axially of the roller over its length and which are adapted to receive rib members releasably mounted thereon.

15. A fountain roller substantially as specifically described herein with reference to any one of Figures 1 to 5 of the accompanying drawings.

16. A dampening device for an offset printing machine, including a fountain roller as claimed in claim 15.

17. An offset printing machine including a dampening device as claimed in any one of claims 13, 14 or 16.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (17)

**WARNING** start of CLMS field may overlap end of DESC **. be made and released again quickly and neatly in a simple manner without recourse to further means. Other forms of connection, however, are possible, for example by means of a burr type material strip which has proved successful particularly with rib members which are particularly light-weight in construction, or by means of screws, or plug or pin and socket connections. In Figure 4 a plug or pin and socket connection is indicated. The rubber strip or piece of the rib member 8 is glued or vulcanized on to a plate 12 which is provided with a pin 11. The pin 11 engages in an interlocking manner into a recess or slot 13 formed in the roller core 6; the interlocking engagement is achieved by a strip 14 which is held over the recess 13 by screws 15, and which has a hole in it the edges of which form an undercut for the head of the pin 11. A number of pins and holes may be provided for each rib member and to insert and retract the pins 11 in the strip 14 the holes may be slots with larger openings disposed laterally relative to a final position of the rib member. Alternatively, the pins 11 may be oval or oblong, for instance, so that the interlocking may be achieved by rotation. If the rib members are screwed onto the roller core 6, there may be provided in the rubber strips through-holes for insertion of the screws, which holes may be closed after the screws are inserted, by means of small plugs, for instance. A particularly good mutual support of the removable rib members 8 on the roller core 6 may be achieved by mutually staggering the rib members in the peripheral direction and in the longitudinal direction as shown in Figure 5. Provided that the corresponding bearing surfaces extend continuously over the entire roller length, adaptation to a very large water requirement may be achieved, for instance, by appropriately increasing the lateral overlap or by arranging the rib members completely alongside each other. WHAT WE CLAIM IS:-

1. A fountain roller for a dampening device for an offset printing machine, comprising a roller core and a plurality of rib members removably mounted on axially extending bearing surfaces on the core, each rib extending axially of the roller over at least a part of the roller length.

2. A fountain roller as claimed in claim 1, in which six circumferentially spaced rib members are provided on the roller core.

3. A fountain roller as claimed in claim 1 or claim 2, in which each rib member extends axially over approximately one quarter of the roller length.

4. A. fountain roller as claimed in any one of claims 1 to 3, in which at least the radially outer part of each rib member is made of rubber.

5. A fountain roller as claimed in claim 4, in which each rib member includes a rubber part mounted on attachment means which cooperates with a bearing surface on the roller core.

6. A fountain roller as claimed in claim 5, in which the rubber part of each rib member is vulcanized to its attachment means.

7. A fountain roller as clained in claim 5 or claim 6, in which the attachment means are releasably held onto the bearing surfaces by magnetism.

8. A fountain roller as claimed in claim 7, in which each attachment means comprises a permanent magnet

9. A fountain roller as claimed in any one of claims 1 to 4, in which the rib members are attached to the roller core by screws.

10. A fountain roller as claimed in any one of claims 1 to 6, in which the rib members and bearing surfaces are adapted so that each rib member is removably attached to the roller core by a cooperating plug or pin and socket connection.

11. A fountain roller as claimed in any one of claims 1 to 6, in which the rib memhers and bearing surfaces are adapted so that each rib member is removably attached to the roller core by a burr material type fastening.

12. A fountain roller as claimed in any one of claims 1 to 11, in which each rib member is staggered in the longitudinal direction of the roller relative to circumferentially adjacent rib members.

13. A dampening device for an offset printing machine, comprising a container for dampening liquid and a fountain roller as claimed in any one of the preceding claims.

14. A dampening device for an offset printing machine, comprising a container for dampening liquid and a roller adapted to serve as a fountain roller, the roller having plane bearing surfaces extending axially of the roller over its length and which are adapted to receive rib members releasably mounted thereon.

15. A fountain roller substantially as specifically described herein with reference to any one of Figures 1 to 5 of the accompanying drawings.

16. A dampening device for an offset printing machine, including a fountain roller as claimed in claim 15.

17. An offset printing machine including a dampening device as claimed in any one of claims 13, 14 or 16.