Arrangement For Adjustment Of The Position Of An Ink Spreader Roll

Abstract

Spreader rolls of ink arrangements, particularly for offset printing machines must not remain in contact with form cylinders in the course of short printing intervals. They equally must not remain in contact with rubbing-down rollers if the machine is put out of operation for a longer period. The spreader roll is mounted on a holder, pivotally supported by a carrier bolt which itself is mounted by means of an adjustable eccentric sleeve in the sidewall of the printing machine. A control bolt is supported substantially coaxial with the spreader roll by the sidewall of the printing machine. The control bolt is provided with a spiral shaped cam engaging with a face on the holder perpendicular to the connecting line of centers of the spreader roll and of the form cylinder.

Description

The present invention relates to an arrangement for adjustably mounting spreader rolls in inking systems of offset machines.

The spreader rolls of ink systems are maintained in contact with rubbing-down rollers, wherefrom they take over a film of printing ink and transmit it in course of rolling to the printing plate. The spreader roll must be removed from the printing plate during a temporary halt in printing in order to prevent an overinking of the printing plate. In case of a longer interruption of the operation of the printing machine, the spreader roll must be removed from contact also with the rubbing-down roller in order to prevent any deformation of the rubber of the spreader roll, which would subsequently show in printing by creating a nonuniform inking. It is therefore necessary, in order to insure a perfect inking to provide an easy adjustment of the pressure of the spreader roll to the rubbing-down roller and an easy possibility of changing the pressure of the spreader roll against the printing plate as required for different kinds of printing.

Known arrangements for supporting spreader rolls of ink arrangements removed from the printing plate by shifting the auxiliary sidewalls, which support the holders of the spreader rolls. Their position is controlled by eccentric means and by set screws, locating the holders and control elements on the inner side of the sidewalls.

This arrangement has the drawback that it is not easily accessible and any adjustment requires a considerable time to effect.

Other arrangements have the holders on the external side of the sidewalls but in this case the spreader rolls can then be removed only with great difficulty.

There are other arrangements, where the hubs of the holders pass through the sidewalls and the spreader rolls are mounted in bearings on the inner side of the sidewalls.

These later arrangements have the drawback of an unstable mounting which is amplified by the length of the overhanging of the hub. The adjustment is also inaccurate and the variable pressures have an adverse influence on the quality of inking of the surface.

It is an object of this invention to provide an arrangement enabling an easy removal and exchange of spreader rolls.

It is another object of this invention to enable an easy removal of the spreader rolls from the printing plate and a further removal from engagement with the rubbing-down rollers.

A further object of this invention is to enable an easy adjustment of the pressure of the spreader roll against the printing plate.

It is still another object of this invention to maintain a constant pressure between the spreader roll and between the rubbing-down roller.

Bearing these and other objects in mind, the arrangement according to this invention is provided with a spreader roll arranged in a holder, which itself is pivotally mounted by means of an eccentric sleeve in the sidewalls of the machine. The centers of the rubbing-down roller of the printing machine, of the spreader roll and of the pivotal mounting of the holder lying in the working position substantially on a common line. Means for adjustment of the angular position of the eccentric sleeve and means for adjustment of the position of the holder of the spreader roll with respect to the form cylinder are provided.

One possible embodiment of the object of this invention is shown schematically in the accompanying drawings where

FIG. 1 is a side view on the holder with rollers

FIG. 2 a sectional view along line A--A of FIG. 1

FIG. 3 shows schematically different relative positions of individual rollers.

As seen in FIGS. 1 and 2 the arrangement according to this invention comprises a holder 1 fixed on the carrier bolt 2 which is supported pivotally by an eccentric sleeve 3, which itself is rotatably mounted in the sidewall 4 of the printing machine. The bearing 5 of the spreader roll 6 is mounted in a recess of the holder 1, and is secured from falling out by a closing arm 7. The arm 7 is pivotally supported on a bolt 21 and secured by a screw 8. The holder 1 is provided with a second recess, forming a rest face 9 for a spiral-shaped cam 10 fixed on a control bolt 11 supported rotatably in the sidewall 4. The eccentric sleeve 3 has a gear 12 meshing with the gear 13 mounted a second control bolt 14. The second control bolt 14 is rotatably mounted in the sidewall 4 of the printing machine and is secured in this position by a snap ring 15. A lever 17 having on its extremity a set screw 18 and midway along its length a bolt 19 is fixed by means of the screw 16 to the external end the carrier bolt 2. One end of a tension or pull spring 20 is suspended on the bolt 19. The other end of the spring 20 is fixed on the sidewall 4 of the printing machine. The spreader roll 6 in he position indicated in FIG. 1 engages both the rubbing-down roller 22 and the form cylinder 23 of the printing machine supporting the printing plate.

In position I (FIG. 3) the spreader roll 6 is in its working position in contact with the rubbing-down roller 22, from which is receives the ink film and with the form cylinder 23 on which the printing plate is fixed, and to which printing plate the printing ink is transferred. Pressure on the printing plate is generated by the spring 20 and the magnitude of said pressure is adjusted by the spring-shaped cam 10 on the control bolt 11, which bears against the rest face 9 of the holder 1. In case of a short interruption of printing, the spreader roll 6 is removed from the form cylinder 23 to position II by a not shown device which reacts on the set screw 18 in direction of the arrow p (FIG. 1). This causes the lever 17 to turn the carrier bolt 2 and thus also the entire holder 1 carrying the center of the spreading roller from positions S1 to S2. In position I the connecting line of the center B of the carrier bolt 2 and of the center K of the rubbing-down roller 22 forms an angle .alpha. with the connecting line of the center B and of the center S.sub.1 of the spreader roll 6. In position II the line between centers B and K form and angle .alpha.' with the connecting line of the center B and the center S.sub.2 of the spreader roll 6. If the angle .alpha. is equal to the angle .alpha.' the pressure of the spreader roll 6 against the rubbing-down roller 22 is in position II as it is the same in position I. The position II is mainly used when rubbing-down the printing ink prior to the actual printing. By further turning the lever 17 the spreader roll 6 comes to position III, where it is in contact neither with the rubbing-down roller 22, nor with the form cylinder 23. Position III is mainly used in case of a longer period of shutdown of the operation of the printing machine. The adjustment of the pressure of the spreader roll 6 with respect to the form cylinder 23 is accomplished by turning the square end of the control bolt 11 to rotate the sprial-shaped cam 10, which bears against the rest face 9 of the holder. The cam causes the holder to move to cause the spreader roll 6 from the form cylinder 23. The pressure of the spreader roll 6 against the rubbing-down roller 22 does not effectively change in the course of this adjustment, as the angle .alpha. of deviation of the holders 1 is very small.

The adjustment of the pressure of the spreader roll 6 with respect to the rubbing-down roller 22 is accomplished by turning the eccentric sleeve 3. By the meshing gears 12 and 13 12 the indentment 13 of the control bolt thus shifting thus the holder 1 in direction toward the rubbing-down roller 22. In the course of this adjustment the already adjusted pressure between the spreader roll 6 and the form cylinder 23 is not changed due to the arrangement of the control bolt 11 since, the axis of which is substantially coincident with the axis of the spreader roll 6, and the rest face 9 of the holder 1 is perpendicular to the connecting line of the center S of the spreader roll 6 and of the center C of the form cylinder 23. A displacement of the holder 1 is thus accomplished which at the place of support of the spreader roll has a tangential direction to the surface of the form cylinder 23, so that the distance of the form cylinder 23 and of the spreader roll 6 remains effectively the same.

Claims

We claim:

1. In combination, an ink transfer system for an offset printing machine having a form cylinder, a rubbing-down roller and a spreader roller, arranged along parallel axes, apparatus for mounting said spreader roller for selective engagement with said form cylinder and rubbing-down roller comprising

a supporting wall,

a holder for receiving said spreader roller,

a carrier shaft extending from said holder through said wall along an axis parallel to said spreader roller,

means for turning said shaft about its axis to move said spreader roller, with respect to said form cylinder and said rubbing-down roller,

a stop surface formed on said holder perpendicular to the line connecting the centers of said spreader roller and the form cylinder,

a control bolt freely rotatable within said wall coaxially with said spreader roller,

a spiral cam fixed on said control bolt and adapted to engage said stop surface,

means for rotating said control bolt whereby rotation of said control bolt causes adjustment of said spreader roller within said holder.

2. The apparatus according to claim 1, wherein said carrier shaft is journaled within an eccentric sleeve freely rotatable within said wall, and including a second control bolt extending through said wall along an axis parallel to said carrier shaft, said second control bolt and said eccentric sleeve having intermeshing gears whereby on turning of said second bolt further angular adjustment of said holder may be made.

3. The apparatus according to claim 1, wherein said holder is formed with a recess, and includes a bearing fixed in said recess adapted to receive said spreader roller, said stop face being formed within said recess and comprising a section of a cylindrical surface coaxial with the form cylinder.

4. An arrangement as set forth in claim 1 wherein the connecting line between the center of said carrier bolt and the center of the rubbing-down roller divides the angle formed by connecting lines of the center of the carrier bolt and the center of the spreader roll in its both extreme positions, in one of which it is in contact with the form cylinder, in the other removed therefrom in the course of short intervals in printing into halves.