US3673959A

US3673959A - Dampening system for lithographic printing press

Info

Publication number: US3673959A
Application number: US30781A
Authority: US
Inventors: Leslie J Jezuit; Harold R Kollars
Original assignee: North American Rockwell Corp
Current assignee: Boeing North American Inc
Priority date: 1970-04-22
Filing date: 1970-04-22
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04

Abstract

A dampening system for a lithographic press which includes a resilient applicator roller in rolling engagement with a resilient intermediate roller which receives dampening fluid from a hard-surfaced hydrophilic roller. Riding on the applicator roller is a distributor roller. The applicator roller is arranged adjacent an ink form roller and the intermediate and distributor rollers are mounted on a subframe which is rockable about the axis of the applicator roller so that when the applicator roller is tripped away from the plate cylinder the intermediate roller may be disengaged from the hydrophilic roller while the distributor roller is swung into engagement with the ink form roller. All rollers on the downstream side of the hydrophilic roller are thus coupled to the ink system for convenient and simultaneous wash-up. The intermediate roller has means arranged approximately at right angles for adjusting the pressure applied by it to the applicator roller and to the hydrophilic roller. The intermediate roller is gear driven from the plate cylinder and serves to drive the applicator roller at press surface speed by frictional contact when the applicator roller is tripped away from the plate cylinder, with a slip clutch being interposed in the gear train so that the speed of the applicator roller is controlled by, and corresponds to, the surface speed of the plate when the applicator roller is in its working position.

Description

United States atent Jezuit et al.

[54} DAMPENING SYSTEM FOR LITHOGRAPHIC PRINTING PRESS [72] Inventors: Leslie J. Jezuit, Lyons; Harold R. Kollars,

Elk Grove Village, both of Ill.

[73] Assignee: North American Rockwell Corporation,

Pittsburgh, Pa.

[22] Filed: April 22, 1970 211 Appl.No.: 30,781

3,146,706 9/1964 Tonkin et al ..101/148 3,504,626 4/1970 Worthington... 101/148 2,276,525 3/1942 Trotter ..10l/350 3,168,037 2/1965 Dahlgren ..101/l48 FOREIGN PATENTS OR APPLICATIONS 715,278 9/1954 Great Britain... .....l01/147 488,444 7/1938 Great Britain ..101/l48 1 July4,l972

Primary ExaminerClyde l. Coughenour Att0rney.lohn R. Bronaugh et al.

[57] ABSTRACT A dampening system for a lithographic press which includes a resilient applicator roller in rolling engagement with a resilient intermediate roller which receives dampening fluid from a hard-surfaced hydrophilic roller. Riding on the applicator roller is a distributor roller. The applicator roller is arranged adjacent an ink form roller and the intermediate and distributor rollers are mounted on a subframe which is rockable about the axis of the applicator roller so that when the applicator roller is tripped away from the plate cylinder the intermediate roller may be disengaged from the hydrophilic roller while the distributor roller is swung into engagement with the ink form roller. All rollers on the downstream side of the hydrophilic roller are thus coupled to the ink system for convenient and simultaneous wash-up. The intermediate roller has means arranged approximately at right angles for adjusting the pressure applied by it to the applicator roller and to the hydrophilic roller. The intermediate roller is gear driven from the plate cylinder and serves to drive the applicator roller at press surface speed by frictional contact when the applicator roller is tripped away from the plate cylinder, with a slip clutch being interposed in the gear train so that the speed of the applicator roller is controlled by, and corresponds to, the surface speed of the plate when the applicator roller is in its working position.

6 Claims, 12 Drawing Figures P'A'TENTEnJufmrz I 3, 73,959

' sum 10rd INVENTORS LESLIE J. JEZUIT HAROLD R. KOLLARS T O NEYS PATENTEUJUL 4 m2 SHEET 3 [IF 4 INVENTORS LESLIE J. JEZUIT HAROLD R. KOLLARS EYS PATENTEDJuL 4 I972 SHEET t Of 4 lNVENTORS LESLIE J. JEZUIT HAROLD R. KOLLARS BY TORNEYS DAMPENING SYSTEM FOR LITIIOGRAPIIIC PRINTING PRESS It is an object of the invention to provide a dampening system for a lithographic printing press having improved water-feeding characteristics and in which a precisely controlled and uniform film of water is applied to the printing plate. It is a related object to provide a continuous dampening system which is completely separated from the inking system when in operation and which constantly equalizes the distribution of water on the applicator roller so that water is fed across the entire width of the printing plate more nearly in accordance with need. More specifically, it is the object of the invention to provide a dampening system which includes, in addition to the usual resiliently surfaced applicator roller, a resiliently surfaced intermediate roller which is gear-driven at the surface speed of the press and which rides against a hardsurfaced hydrophilic roller which-is rotated at an adjustable, slower speed so that slippage takes place between the two thereby to control the rate of feed.

It is yet another object of the present invention to provide a dampening system for a lithographic press which is easily and quickly cleaned of any casual ink which may adhere to the applicator roller and the rollers which are immediately associated with the applicator roller on the downstream side of the hydrophilic roller. Accordingly, it is an object to provide a dampening system in which the cluster of rollers on the downstream side of the hydrophilic roller are movable as a group out of contact with the plate on the plate cylinder, out of contact with the hydrophilic roller, and into fluid transferring contact with an adjacent ink form roller so that they may be washed-up in unison with the ink rollers without any possibility of contaminating the surface of the hydrophilic roller. It is a more specific object of the invention to provide a dampening system for a lithographic press which includes an intermediate roller and distributor roller riding in engagement with the applicator roller and in which a subfrarne is provided for rocking the intermediate roller and distributor roller about the axis of the applicator roller when the latter is tripped away from the plate for switching from the operating condition to the condition of wash-up.

In one of the aspects of the invention it is an object to provide improved means for independently adjusting the pressure exerted by the intermediate roller upon the applicator roller, and by the intermediate roller upon the hydrophilic roller, which is susceptible of fine adjustment but which permits quick release of pressure when the press is shut down without affecting the adjustment, and whereby the rollers of the system can be quickly returned to their pre-established pressure setting when the press is restarted.

In another aspect of the invention it is an object to provide a resilient pan roller which not only has provision for adjustment toward and away from the hydrophilic roller to vary the pressure applied thereto but which also includes means for skewing the pan roller relative to the hydrophilic roller for lateral control of the feed of water.

It is still another object of the present invention to provide a dampening system for a lithographic press which is an improvement over conventional and widely used systems in terms of the quality and consistancy of the final result and in terms of the ease and simplicity of operation, particularly when switching between normal operation and wash-up.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIG. 1 is a diagram showing arrangement of rollers employed in carrying out the present invention in their respective positions or operating modes.

FIG. 2 is a vertical section taken substantially along the line 2-2 in FIG. 3.

FIG. 3 is a developed section looking along the line 3-3 in FIG. 2.

FIG. 4 is a vertical section taken along the line 4-4 in FIG. 3.

FIG. 4a is a fragmentary view looking along line 4a 4a in FIG. 4.

FIG. 5 is a fragmentary end view looking along the line 5-5 in FIG. 3.

FIG. 5a is a figure similar to FIG. 5 but showing the dampener rollers tripped ofi to silence the water feed.

FIG. 5b is a view similar to FIG. 5a but showing the terminal roller cluster spaced from the hydrophilic roller and in contact with the ink form roller for wash-up purposes.

FIG. 6 is an enlarged fragment showing the releasable adjusting mechanism for controlling the pressure between the intermediate roller and the applicator roller.

FIG. 7 is a developed vertical section showing pan and hydrophilic rollers taken generally along the line 7-7 in FIG. 5

FIG. 8 is a fragmentary section showing means for mounting the distributor roller including provision for pressure adjustment and quick release.

FIG. 9 is a fragmentary section taken along the line 9-9 in FIG. 8.

While the invention has been described in connection with a preferred embodiment, it will be understood that we do not intend to be limited to the particular embodiment shown but intend, on the contrary, to cover the various alternative and equivalent constructions which may be included within the spirit and scope of the appended claims.

Turning now to the drawings and particularly to FIGS. 1-4, the dampening portion 10 of a lithographic printing press is shown co-operating with a plate cylinder 13 which is journaled in suitable bearings between the usual side frame plates (not shown). It will be understood by those skilled in the art that the plate cylinder has the usual provision for mounting a lithographic printing plate 14 and is equipped with the usual blanket and impression cylinders, which, for the sake of simplicity, have been omitted from the drawings. It will also be understood that the press has an inking system for applying a film of ink to the ink receptive areas of the plate on the plate cylinder, such system including a train of rollers and cylinders beginning at an ink fountain and terminating in one or more resiliently surfaced ink form rollers of which one, indicated at 15, is pertinent to the present invention.

Characteristic of a press of the lithographic type, a somewhat similar system is provided for applying a film of water or equivalent dampening fluid to; the surface of the plate where it is taken up by the water-receptive non-image areas and repelled by the image areas. In accordance with the present invention the dampening system includes a resilient applicator roller, sometimes referred to as a "water form" roller, a hard-surfaced hydrophilic roller, and an intermediate resilient roller which serves to uniformly distribute and transfer a continuous film of water from one to the other. Thus, referring to the drawings, the applicator roller indicated at 20 rolls in contact with the plate on the plate cylinder and with an intermediate roller indicated at 21. The intermediate roller receives a film of dampening fluid from a hydrophilic roller 22 which has a hard, smooth surface, of for example, chromium, selected because of its known ability when properly treated to receive water and to repel ink.

Arranged below the hydrophilic roller is a pan roller 23 which is resiliently surfaced and is partially immersed in water or other dampening fluid 24 that is maintained at a constant level in a pan 25.

For the purpose of more evenly distributing the film of water on the surface of the applicator roller 20, considering that certain areas across the width of the plate may, on the average, require more water than others, a distributor roller 26, which may be relatively hard-surfaced, is positioned adjacent the applicator roller and rotates with it by reason of frictional contact. The distributor roller is preferably selfreciprocated, sometimes referred to as self-oscillating" so that it moves back and forth through a stroke of several inches as it rotates. The means for inducing the endwise movement, while not shown, is well known to those skilled in the art and is, of itself, the subject of prior patents.

The set of rollers as just described, together with the pan and the various adjusting and drive means to be described, are

formed into a self-contained subassembly included between a pair of

end plates

27, 28 bridged by suitable cross members 29 (FIGS. 4 and 7). Depending upon the design of the press the dampening unit may be enclosed within the main frame plates of the press or may extend outboard. It is one of the features of the construction that, of the rollers in the dampening system, the only one which occupies a fixed position with respect to the

frame plates

27, 28 is the hard-surfaced hydrophilic roller 22, all of the other rollers being capable of movement or adjustrnent in directions normal to their rotational axes.

In accordance with the invention a gear train, coupled to the plate cylinder, is provided for rotating the intermediate roller 21 at press surface speed, with a slip or friction type clutch being interposed in the gear train to accommodate any slight difference in surface speed between the intermediate roller and the plate cylinder when the applicator roller is running in normal contact with both of them, thereby to insure that the applicator roller is synchronized with the plate and avoiding relative scufiing movement. The gear train which drives the intermediate roller may be understood by reference to FIGS. 2 and 3. The gear 30 on the plate cylinder meshes with a first gear 31 which is mounted for rotation about a shaft 32. For frictionally coupling the gear 31 to the shaft a clutch disc 33 is provided which is keyed to the shaft by a key 34 and is pressed against the gear by means of a spring 35, the spring being held captive under predetermined axial pressure by means of a pair of nuts 36 threaded onto the end of the shaft. Keyed to the opposite end of the shaft 32 is a gear 40 which meshes with an idler gear 41. The gear 41, in turn, meshes with an idler gear 42 mounted coaxially and freely rotatable with respect to the applicator roller 20. The gear 42 drives a gear 43 which is keyed to one end of the intermediate roller 21.

As a result, no reliance is placed upon surface friction in the driving of the intermediate roller and the roller is rotated more or less positively, at the surface speed of the plate cylinders. The presence of the slip clutch, including the disc 33 engaging the side of the gear 31, insures that any slight difference between the surface speed of the intermediate roller and the surface speed of the plate on the plate cylinder will be accommodated by slight slippage, so that the applicator roller will rotate precisely in step with the plate on the plate cylinder.

Means are provided for rotating the hydrophilic roller 22 and the pan roller 23 at an adjustable speed which is substantially less than the surface speed of the plate cylinder in order to control the amount of dampening fluid which is fed through the system. Such drive means is shown diagrammatically in FIG. 1 as the variable slow speed drive mechanism 50, to which more detailed reference will be made. It will sufiice, for the present, to say that slippage occurs between the intermediate roller 21, which operates at substantially plate cylinder speed, and the more slowly rotating hydrophilic roller 22. While the clutch disc 33 is set to yield in the face of any speed differential with respect to the surface of the plate, the setting of the clutch is, nevertheless, sufi'r'ciently stiff so that there is no tendency for the intermediate roller to reduce its speed to the surface speed of the hydrophilic roller which it engages.

For the purpose of tripping the applicator roller clear of the plate and for disengaging the intermediate roller from the hydrophilic roller to cut off flow of water from the latter, tripping means are provided to swing the applicator roller and intermediate roller from the position in FIGS. 1-5 to the position shown in FIG. a. This accomplished by mounting the applicator roller 20, not in the

frame plates

27, 28, but rather on levers or

arms

61, 62 which are coaxially mounted in the frame plates for rocking movement through a limited angle. The lever 61 is secured to the adjacent frame plate on a pin 63, while the opposite lever 62 is secured on a coaxially arranged pin 64. The lever 61 is operated by a pneumatic actuator 65 anchored to the frame plate 27 by a mounting pin 66 while the lever 62 has an actuator 67 pinned to the frame plate 28 at 68. For the purpose of joumaling the applicator roller and intermediate roller 21,

brackets

71, 72 are provided mounted upon

non-rotatable stub shafis

73, 74, respectively, carried by the pivot levers 61, 62 and which are alined with the axis of the applicator roller 20. The brackets carry the outer races of

anti-friction bearings

75, 76, with the stub shafts 20a, 26b at the ends of the applicator roller 20 being received in the inner races. Similarly,

anti-friction bearings

77, 78 mounted on the

brackets

71, 72 engage stub shafts of 21a, 2112 on the intermediate roller 21.

To determine the working position of the applicator roller and intermediate roller, stops are conveniently provided in the paths of movement of the

levers

61, 62. Such stops may be in the form of a fixed stop 80 (FIG. 5) engaged by a stop screw 81 threaded into each lever and held in adjusted position by a lock nut 82. Thus, under working conditions, the

actuators

65, 67 are pressured (by means not shown) for extension to bottom the levers against the stop surfaces 80, and when it is desired to retract or trip the applicator roller, the pressure in the actuators is reversed (also by means not shown), withdrawing the levers and the

rollers

20, 21 into the tripped position shown in FIG. 5a.

During retraction, separation takes place first between the applicator roller and the plate and secondly between the intermediate roller and the surface of the hydrophilic roller, thus cutting off any further feeding of water from the hydrophilic roller. The gear train driving connection to the intermediate roller remains unaffected by the retraction, so that the intermediate roller 21, and the applicator roller which is in rolling engagement with it, continue to rotate at press speed. To minimize the efiect of retraction upon the gear train, the pivot pins 63, 64 which mount the

levers

61, 62 are preferably located in a plane which inter-connects the centers of the idler gears 41 and 42. When the

actuators

65, 67 are next pressurized to move the applicator roller and intermediate roller into working position, the moving intermediate roller first engages the hydrophilic roller to reestablish the flow of water, and the wetted applicator roller, pre-rotated at press speed, is brought into engagement with the surface of the printing plate. At the moment of engagement, the applicator roller will be rotating at substantially the same speed as the plate, due to the friction drive between the intermediate roller and the applicator roller, thereby to avoid any scufi'mg of the plate and any slight speed difference thereafter will be accommodated by slippage at the friction-clutch 33 as previously described.

In accordance with one of the important aspects of the present invention, the applicator roller 20 is mounted by its supporting framework in a position adjacent to but spaced from the ink form roller, and the subframe which carries the intermediate roller, and the distributor roller is mounted for rocking movement about the axis of the applicator roller between an operating position already described and a washup position in which the intermediate roller is further separated from the hydrophilic roller and in which the distributor roller is in rolling engagement with the ink form roller. In this position, any ink which may have been casually deposited in the final cluster of dampening rollers downstream from the hydrophilic roller can readily be removed during wash-up of the inking system. Thus the distributor roller 26, having stationary stub shafts 26a (see FIG. 2 and 8) is mounted upon the

brackets

71, 72 which together form a subframe capable of rocking about the axis of the applicator roller 20. To achieve and control the rocking movement, actuators 91, 92 are provided (FIGS. 2 and 3), each of which has a plunger pivot connection 93 with its

respective bracket

71, 72 and an anchoring pivot connection 94 with the

respective frame plates

27, 28.

It will be apparent that these actuators serve as supporting links for the free ends of the brackets 71-72 and maintain said brackets in a predetemrined angular position while the dampener is in operation with the applicator roller in contact with the plate cylinder. The respective pivot axes 93 and 94 thereof are so located that when the applicator roller is moved to its tripped" position, the actuators 91-92 will pivot about axes 94 and guide the brackets in a path such that the intermediate roller will remain in contact with the hydrophilic roller during the initial tripping motion and for a predetermined period after the applicator roller has moved out of contact with the plate cylinder. Thereafter, during the final tripping motion, the intermediate roller will be caused to move out of contact with the hydrophilic roller as illustrated in FIG. 5a. When the dampener is tripped back to its operative position, the motion is such that the intermediate roller contacts the hydrophilic roller before the applicator roller moves into contact with the plate cylinder. This sequence is necessary to assure that the intermediate and applicator rollers will be coated with water before the applicator roller is in contact with the plate cylinder.

If desired the apparatus can be modified to have an intermediate trip position wherein the applicator roller is tripped away from the plate cylinder and the intermediate roller remains in contact with the hydrophilic roller. In such case, the operator can maintain the applicator and intermediate rollers in the intermediate trip position during short press stops to assure that their surfaces will remain wet. Also, when tripping back to the operative position from the fully tripped off position after the press has been stopped for a long period of time, the intermediate and applicator rollers can be stopped in the intermediate trip position for an extended period to assure that they are thoroughly wetted before the applicator roller is moved into contact with the plate on the plate cylinder.

When the actuators 91-92 are pressurized to extend the plungers (by means not shown), the

brackets

71, 72 are rocked forwardly in the counter-clockwise direction as shown in FIG. 5b. For determining the limit of forward movement, each of the

brackets

71, 72 carries an adjustable stop screw 95 which is set so that it engages a stop 96 when the distributor roller is in slightly indenting relation to the ink form roller 15.

It may be noted that rocking of the

subframe

71, 72 into the wash-up position does not affect the rotation of the intermediate roller 21 since the gear 43 which drives it meshes with a gear 42 which is concentric with the applicator roller about which rocking occurs. Thus, all of the rollers of the cluster will continue to be rotated during the wash-up procedure without placing any reliance upon frictional driving by the ink form roller. As will be understood by one skilled in the art, the constant watercoating of the distributor, applicator and inter mediate rollers tends to make them ink-repellent so that the ink accumulated on the surfaces even after a long run is casual and in limited quantity, and is easily removed during a short cleaning cycle. It may also be noted that during the cleaning cycle the isolation which exists between the intermediate roller and the hydrophilic roller 22 prevents any of the washup solvent from reaching the surface of the hydrophilic roller which might affect its water-receptive characteristics.

When the cleaning cycle is complete, the direction of pressure in the

actuators

91, 92 is reversed, rocking the

subframe

71, 72 in a clockwise direction to thereby separate the distributor roller 26 from the ink form roller and return the intermediate roller 21 to its normal tripped position slightly spaced from the hydrophilic roller 22.

For the purpose of determining the normal running position of the intermediate roller with respect to the hydrophilic roller which is fixedly journaled in the frame, an eccentric connection is provided at the plunger pivots 93. Thus, referring to FIG. 3 the eccentric connection associated with the actuator 91 includes a stub-shaft 95 which is rockably mounted in the bracket 71 and which is integral with the plunger pivot 93 but eccentric with respect to it. Pinned to the stub-shaft 95 is a manual rocking arm 96. The bracket 71 is split as indicated at 97 (see FIG. 2) with the split bridged by a clamping screw 98 so that the stub-shaft may be tightly clamped in its adjusted position. A corresponding connection is provided in bracket 72. It will be apparent that the amount of throw of the eccentric defines the permissible range of adjustment of the subframe when the

actuators

91, 92 are internally bottomed in the contracted condition. This determines the running pressure which exists between the intermediate roller and the hydrophilic roller under operating conditions until such pressure is intentionally changed by rocking the eccentric adjusting levers 96.

in carrying out the present invention, the applicator, intermediate and hydrophilic rollers are arranged so that a line interconnecting their centers, line 101-103 in FIG. 4, defines an approximate right angle to permit individual adjustment of the pressure between the intermediate roller and the rollers which it engages. Mention has already been made of the adjustable eccentric connections which are used for adjusting the operat' ing presure between the intermediate roller and the hydrophilic roller. To understand the means, at right angles thereto, for adjusting the running pressure between the intermediate roller and the applicator roller, reference is made to FIGS. 24a and 6. The

bearings

77, 78 which mount the stub-shaft 21a and 21b of the intermediate roller 21 are mounted in sliding blocks which fit in to recesses 111 which extend radially, with respect to the applicator roller, in the

brackets

71, 72. Bearing downwardly upon each of the blocks is a bridge 113 (see FIGS. 4 and 4a) which is pinned to the supporting bracket at 114 and which is slotted as indicated at 115 (FIG. 6) for reception of an adjustable hold-down 116. The holddown is in the form of a bushing penetrated by a clamping screw 1117 which is screwed into the bracket and which has a locking nut 118. The bushing has an integral arm, or lug, 119 which projects laterally into the slot 115 of the bridging member. Thus, in making an adjustment, and with lock nut loose, the screw 117 at each end of the intennediate roller is turned to apply pressure to the bridge which, in turn, is transmitted to the slidable block and thus to the bearing and roller. When the desired pressure is achieved, the lock nuts are tightened. This adjustment is independent in the sense that the pressure against the hydrophilic roller, at 90, is unaffected. When it is desired to relieve pressure at the end of a run, the arms 1 19 are simply swung out of the slots 115, thereby releasing the bridges 113 to release the pressure upon the roller. This does not disturb the adjustment, and, when it is desired to operate the press, the arms are swung into the slots to reestablish the pressurized condition.

The means for pressurizing the distributor roller 26 with respect to the applicator roller is shown in FIGS. 8 and 9. Here a stationary stub-shaft 26a on the roller is received in a recess 71a formed in the bracket 71, the recess 71a having a rectangular access opening 71b. Extending transversely from the stubshaft is a pin 120 which has, telescoped over it, a hollow adjusting screw 121 which is threaded into a rectangular retaining plate 122. The plate normally occupies a position extending transversely of the access opening 71b as shown in FIG. 9 to maintain the plate captive. interposed between the end of the adjusting screw 121 and the stub-shaft 26a is a spring 123. Completing the assembly is a lock nut 124. To adjust the pressure which is applied by the distributor roller, the adjusting screw 121, with the lock nut 124 backed off, is screwed into the retaining plate 122 to thereby increase the tension of the spring 123. The pressure developed in the spring reacts against the roller. Tightening the lock nut 124 makes this adjustment permanent. A similar pressurizing arrangement is used at the opposite end of the roller. To relieve the pressure applied by the distributor roller 26 at the end of a run, it is a simple matter to rotate the retaining plate 122 so that it extends into the alternate (dot-dash) position (FIG. 9) in alinement with the access opening 71b. In this position the complete distributor roller assembly can readily be removed. Pressure is reestablished by rotating the plate 122 back into its transversely extending position.

Having understood the construction, mounting and adjustment of the rollers on the

subframe

71, 72, more detailed attention may be given to the mounting of the hydrophilic roller 22 and pan roller 23, with special reference to FIGS. 5 and 7. As shown in FIG. 7, the stub-shafts 22a, 22b of the hydrophilic roller 22 are mounted in bearings 131, 132 which are secured in fixed

brackets

133, 134 which are mounted upon the inner faces of the

frame members

27, 28. The stub-

shafts

23a, 23b

of the pan roller are mounted in

bearings

135, 136. The bearing 136 is mounted in the lower end of the fixed bracket 134, the latter being fixed to the adjacent frame plate by a pin 138 and clamping screw 139.

For the purpose of permitting skewing movement in one direction or the other of the pan roller with respect to the hydrophilic roller, the opposite bearing 135 is mounted in a bracket which is adjustably swingable, pendulum-like, about a mounting pin which is alined with the shaft of the hydrophilic roller. Thus an auxiliary frame member or bracket 140 is provided which is positioned closely adjacent the inner face of the frame member 27 and which is swingable about a pin 141 alined with the axis of the hydrophilic roller. Mounted in the lower end of the swingable bracket 140 is a pin 142 which is alined with the axis of the pan roller and which extends through a clearance opening 143 in the frame plate. A handle 144 at the outer end of the pin 142 provides a convenient grip for lateral adjustment. Extending to one side of the handle 144 (FIG. is an adjusting screw 145 which is telescoped into a pivoted block 146 having capstan nuts 147 on each side. For locking the swinging bracket in place, a clamping screw 150 is used having a lateral clearance hole 151 in the frame.

Accordingly, when it is desired to skew the pan roller 23 in one direction or the other, the clamping screw 150 is loosened, the capstan nuts 147 are backed off, and the handle is nudged in one direction or the other in accordance with the reading on a scale 153. Skewing the roller 23 products a change in the pressure distribution between the pan roller and the hydrophilic roller along the length of the pan roller and provides for lateral control of the water fed to the hydrophilic roller. When the proper adjustment is achieved, the capstan nuts and clamping screw are tightened to preserve the adjustment. Adjustment of the pressure of the pan roller against the hydrophilic roller is accomplished by bridges 155 and clamping screws 156 which correspond rather closely to the bridges 113 and screws 117 which have been discussed in connection with FIGS. 4a and 6, and the description need not be repeated.

Turning next to the means for driving the hydrophilic roller and pan roller at a slow but adjustable speed, reference is made to the driving train shown in FIG. 7. Here it will be noted that a motor 160 has an output pinion 161 meshing with a gear 162 on a jack shaft 163. Keyed to the opposite end of the shaft is a pinion 164 which meshes with a gear 165 which is keyed to the stub-shaft 22b of the hydrophilic roller. The gear 165, in turn, meshes with a gear 166 which is keyed to the stub-shaft 23b of the pan roller, the gears having the same pitch diameter as the rollers which they drive. The drive motor 160 may be either of the AC or DC type having an appropriate speed controller diagrammatically illustrated at 167. Since slippage takes place at the polished surface of the hydrophilic roller, it is found that there is less tendency for any ink to be transferred to the surface of such roller than is the case where the hydrophilic roller rotates at the same surface speed as the roller which it supplies.

It will be apparent to one skilled in the art that the dampening system described above possesses a number of different inherent advantages. The particular sequence of rollers from the pan roller to the applicator roller has been found to be highly advantageous in controlling the feed and distribution of the water, quite apart from the advantageous wash-up feature. The design of dampening system includes elements of art as well as science, and the inventors consider that they have discovered a particular arrangement of hard and resiliently surfaced rollers which produces uniquely advantageous results. Notwithstanding the fact that four rollers are used in the drive train rather than the three which characterize many conventional dampening systems, and in spite of the wide range and variety of adjustment which the structure affords, it is found that the dampening system is inherently economical to construct and operate as well as being inherently durable requiring little or no maintenance. While the term water" has been used in the above description, it will be understood that this term is used in a generic sense to include any equivalent liquid non-miscible with grease.

In the preferred embodiment a reciprocating distributor roller is used, not only for longitudinally distributing the water film on the applicator roller, but also to maintain the ink which unavoidably adheres to the applicator roller active and prevent it from drying or piling which would adversely affect its water carrying capabilities. Moreover, the distributor roller constitutes a convenient means for establishing contact with the ink form roller for wash-up purposes. It will be understood, however, that, if desired, the distributor roller may be omitted or switched to the other side of the applicator roller in which case the entire assembly may be canted counter-clockwise and lowered so that the intermediate roller, when in normal operating position, is spaced relatively closely to the ink form roller 15. In this way the rocking of the

subframes

71, 72, following tripping of the applicator roller, will bring the intermediate roller into running engagement with the ink fonn roller for the wash-up mode to remove any casually acquired ink.

It is one of the features of the present construction that efficient operation is possible for both directions of rotation of the plate cylinder. Where it is desired to make full use of a distributor roller 26 in both of the directions of rotation, a second distributor roller may be provided below the applicator roller and employed for opposite direction of rotation with the upper distributor roller optionally silent.

What we claim is:

1. In combination with a lithographic printing press having a frame, a rotatable cylindrical printing surface supported by the frame, and an ink form roll contacting and applying ink to the printing surface, a dampener comprising a resilient applicator roll for applying dampening fluid to the press printing surface, a hard, smooth surfaced, hydrophilic roll for supplying dampening fluid for the applicator roll, a resilient intermediate roll for transferring dampening fluid from said hydrophilic roll to said applicator roll, first mounting means rotatably supporting said applicator roll and pivotally movable relative to the press frame to and from a first position and a second position for selectively engaging and disengaging said applicator roll in and from rolling contact with the press printing surface, second mounting means rotatably supporting said intermediate roll and pivotally movable relative to said first mounting means to and from a first position and a second position for selectively engaging and disengaging said intermediate roll in and from rolling contact with the ink form roll and alternately in and from rolling contact with said hydrophilic roll, first actuator means connected to said first mounting means for selectively pivoting said first mounting means to and from said first mounting means first and second positions, and second actuator means connected to said second mounting means for selectively pivoting said second mounting means to and from said second mounting means first and second positions, said intermediate roll simultaneously contacting said applicator roll and said hydrophilic roll when said first mounting means is pivoted to said first mounting means first position and said second mounting means is pivoted to said second mounting means second position and simultaneously contacting said applicator roll and the press ink form roll when said first mounting means is pivoted to said first mounting means second position and said second mounting means is pivoted to said second mounting means first position.

2. The invention defined by claim 1 wherein said second mounting means is supported on said first mounting means pivotally at the rotational axis of said applicator roll, said intermediate roll being maintained in constant contacting relation to said applicator roll whenever said second actuator means is actuated.

3. The invention defined by claim 2 wherein said second actuator means is provided with a pair of pivot connections, one of said pivot connections coupling said second actuator means to the press frame and the other of said pivot connections coupling said second actuator means to said second mounting means, said second actuator means pivot connections being located in a manner whereby actuation of said first actuator means to move said first mounting means to said first mounting means second position causes said applicator roll to be disengaged from contacting the press printing surface and subsequently said intermediate roll to be disengaged from contacting said hydrophilic roll.

4. In combination with a lithographic printing press having a frame, a rotatable cylindrical printing surface supported by the frame, and an ink form roll contacting and applying ink to the printing surface, a dampener comprising a resilient applicator roll for applying dampening fluid to the press printing surface, a distributor roll for evenly distributing any ink film retained on the surface of said applicator roll, a hard, smooth surface, hydrophilic roll for supplying dampening fluid for the applicator roll, a resilient intermediate roll for transferring dampening fluid from said hydrophilic roll to said applicator roll, first mounting means rotatably supporting said applicator roll and pivotally movable relative to the press frame to and from a first position and a second position for selectively en gaging and disengaging said applicator roll in and from rolling contact with the press printing surface, second mounting means rotatably supporting said distributor roll and said intermediate roll spaced from said distributor roll and pivotally movable relative to said first mounting means to and from a first position and a second position for selectively engaging and disengaging said distributor roll in and from rolling contact with the ink form roll and alternately said intermediate roll in and from rolling contact with said hydrophilic roll, first actuator means connected to said first mounting means for selectively pivoting said first mounting means to and from said first mounting means first and second positions, and second actuator means connected to said second mounting means for selectively pivoting said second mounting means to and from said second mounting means first and second positions, said intermediate roll simultaneously contacting said applicator roll and said hydrophilic roll when said first mounting means is pivoted to said first mounting means first position and said second mounting means is pivoted to said second mounting means second position, and said distributor roll simultane ously contacting said applicator roll and the press ink form roll when said first mounting means is pivoted to said first mounting means second position and said second mounting means is pivoted to said second mounting means first position.

5. The invention defined by claim 4 wherein said second mounting means is supported on said first mounting means pivotally at the rotational axis of said applicator roll, said distributor roll and said intermediate roll being maintained in constant contacting relation to said applicator roll whenever said second actuator means is actuated.

6. The invention defined by claim 5 wherein said second actuator means is provided with a pair of pivot connections, one of said pivot connections coupling said second actuator means to the press frame and the other of said pivot connections coupling said second actuator means to said second mounting means, said second actuator means pivot connections being located in a manner whereby actuation of said first actuator means to move said first mounting means to said first mounting means second position causes said applicator roll to be disengaged from contacting the press printing surface and subsequently said intermediate roll to be disengaged from contacting said hydrophilic roll.

Claims

4. In combination with a lithographic printing press having a frame, a rotatable cylindrical printing surface supported by the frame, and an ink form roll contacting and applying ink to the printing surface, a dampener comprising a resilient applicator roll for applying dampening fluid to the press printing surface, a distributor roll for evenly distributing any ink film retained on the surface of said applicator roll, a hard, smooth surface, hydrophilic roll for supplying dampening fluid for the applicator roll, a resilient intermediate roll for transferring dampening fluid from said hydrophilic roll to said applicator roll, first mounting means rotatably supporting said applicator roll and pivotally movable relative to the press frame to and from a first position and a second position for selectively engaging and disengaging said applicator roll in and from rolling contact with the press printing surface, second mounting means rotatably supporting said distributor roll and said intermediate roll spaced from said distributor roll and pivotally movable relative to said first mounting means to and from a first position and a second position for selectively engaging and disengaging said distributor roll in and from rolling contact with the ink form roll and alternately said intermediate roll in and from rolling contact with said hydrophilic roll, first actuator means connected to said first mounting means for selectively pivoting said first mounting means to and from said first mounting means first and second positions, and second actuator means connected to said second mounting means for selectively pivoting said second mounting means to and from said second mounting means first and second positions, said intermediate roll simultaneously contacting said applicator roll and said hydrophilic roll when said first mounting means is pivoted to said first mounting means first position and said second mounting means is pivoted to said second mounting means second position, and said distributor roll simultaneously contacting said applicator roll and the press ink form roll when said first mounting means is pivoted to said first mounting means second position and said second mounting means is pivoted to said second mounting means first position.