US3306255A - Dampening apparatus for planographic printing - Google Patents

Description

Feb. 28, 1967 J. A. KOLIBAS DAMPENING APPARATUS FOR PLANOGRAPHIG PRINTING Filed Feb. 5, 1964 INVENTOR. JA MES A. KOL/EAS BY 2 ATTORNE' K United States Patent 3,306,255 DAMPENING APPARATUS FOR PLANOGRAPHIC PRINTING James A. Kolibas, Cleveland, Ohio, assignor to Addressagraph-Multigraph Corporation, Cleveland, Ohio, a corporation of Delaware Filed Feb. 5, 1964, Ser. No. 342,680 2 Claims. (Cl. 118-227) This invention relates to printing, and particularly to printing according to the planographic, lithographic principle.

In this form of printing, a master or plate bearing a water-repellent, ink-receptive image is employed. Ink and an aqueous ink repellent liquid are applied either simultaneously 0r alternately to the master, the ink adhering to the imaged areas and the repellent to the unimaged areas. However, prior to the application of such ink and repellent, the master usually is conditioned with a predampening or etching solution, and it is with an apparatus for applying the pre-dampening solution or liquid that this invention is concerned.

In the past, pre-dampening solution has been applied to a master either manually with a cotton swab or the like, or by manually operated devices, such as for example, those shown in US. Patents Nos. 2,443,458 and 2,798,- 426. Such devices have proven highly satisfactory in that they save time and eliminate contact between an operators hands and the solution. However, the present invention provides an improved means for applying the pre-dampening solution in that it is completely automatic.

Thus, the primary object of this invention is to provide a fully automatic means for applying a dampening, or pre-dampening solution to a planographic printing plate or master.

Another object of the invention is to provide a means for dampening a master prior to the time the master is attached to a printing drum and while the printing or duplicating machine is running copy from a previously treated master, thus enabling the master to be dampened and made ready without stopping the machine or interrupting its work cycle.

Another object of the invention is to afford means to apply dampening solution or liquid to a planographic master while the master is in motion and while it is being guided toward a master retaining means mounted in the printing drum of a printing machine.

Still another object is to apply dampening solution in a uniform film to a plan-ographic master.

Another object of the invention is provision for applying dampening solution uniformly to a planographic master and simultaneously removing any excess solution therefrom.

A further object of the invention is to provide a master pre-dampening means which may be in the form of an attachment to a duplicating or printing machine, rather than an integral part of such machine, thus permitting the pre-dampening means to be affixed to existing machines.

A duplicating or printing machine of the kind with which this invention may be utilized is shown in Patent No. 3,056,346, assigned to the assignee of the present invention.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings, in which:

FIG. 1 is a schematic illustration, partly in section, of the invention, showing the apparatus prior to pre-dampening of the master;

FIG. 2 is a schematic illustration, partly in section,

similar to FIG. 1, but showing a master in the course of the pre-dampening application;

FIG. 3 is an enlarged section taken on line 33 of FIG. 1; and

FIG. 4 is a diagrammatic view showing the pre-dampening roller in its operative and inoperative positions.

In FIG. 1 there is shown a master pre-dampening attachment having a pair of side frames 20, only one of which need be shown for the purposes of explaining this invention. Aflixed to the frames 20 there is provided a feed table 22 adapted to accommodate a supply of masters 24 each bearing on its upper surface an image to be reproduced. A weighted member 26 serves to urge the stack of masters 24 firmly against the feed table 22. As will be readily seen, depression of the handle 28 will raise the Weighted member 26 through a gear and rack arrangement, 3032, thereby enabling an operator of the printing or duplicating machine to replenish the supply of masters on the feed tray 22 or to place additional masters on top of the existing supply. As shown, the handle 28 is affixed to shaft 34 which is journalled in the side frame 20.

Also mounted on side frames 20 is a master separating and deflecting means 36 comprising a first vertical portion 38 and a second vertical portion 40, the portion 40 terminating at its lower edge in an arcuately formed deflecting means 42, the purpose of which will be described hereinafter. Vertical portion 38, it should be noted, has a dual function, i.e., it provides an abutment for the front or leading edges of the uppermost of the masters 24, and it also affords a means of separating the lowermost master from the master supply. For this latter purpose, the vertical portion 38 is so positioned that its lower edge 38a is slightly above the top of feed tray 22, thus providing a space which is slightly greater than the thickness of one master and is effective to permit the passage of only the lowermost master.

Referring further to FIG. 1, there are shown a first pair of intermediate feed rollers 44 and 46 between which the duplicating masters are fed enroute to the pre-dampening station. Roller 46 is mounted on a continuously driven shaft 48 which is journalled in side frames 20, and; roller 44 is mounted on shaft 50. Each end of shaft 50' is engaged by a link 52, only one of which is shown, the links being pivotally mounted on the shaft 54. Shaft 54 is also journalled in side frames 20.

To afford adjustment between the rollers 44 and 46, for example to accommodate masters of various thicknesses, there is provided a springpin arrangement as follows. A lug 56 is aflixed to side frame 20, the lug having an opening to accommodate the pin 58. Pin 58 at its upper end has a head 58a and at its lower end is threaded so as to have threaded engagement with a threaded opening 58b in link 52. As will be readily seen, turning of the pin 58 in one direction will raise the link 52, thus lifting the roller 44 in a direction away from roller 46, and turning the pin in the opposite direction will allow spring 60 to lower the link 52 and roller 44 toward roller 46. Spring 60 serves the dual function of frictionally retaining the pin 58 in its adjusted position and of providing a cushion to insure that the masters 24 are firmly held While they are being fed through the pre-dampening attachment. Thus, a wide range of various thicknesses of masters can be efiiciently passed between the rollers 44 and 46 without hesitation and without damage to the sensitive surface of the masters. The rollers 44 and 46 are preferably, although not necessarily, of rubber or the like.

With further reference to FIG. 1, there is provided a second pair of rollers 62 and 64, the purpose of which will now be described. Roller 62 is carried by shaft 66 and roller 64 by shaft 68, both of said shafts being journalled in side frames 20. Shaft 66 is also continuously driven.

Roller 62, it will be noted, is partially submerged in a predampening or moistening solution or liquid 70, contained in a trough or fountain 72. Roller 64, which may also be referred to as a transfer roller, is eccentrically mounted on shaft 68 above roller 62 in a manner to be described hereinafter.

Roller 62 may be of a material such as aluminum or rubber, for example, although the invention is not intended to be limited to these materials. It is only suggested that a rigid or semi-rigid non-absorbent material be used which is capable of carrying the pre-dampening or moistening solution and which will not corrode or be otherwise adversely affected by the solution. Transfer roller 64- may have a surface of various materials including metal and natural or synthetic rubber. In the preferred form illustrated, however, it carries on its periphery a soft absorbent cover 74, for example molleton cloth or the like.

As stated hereinabove, the transfer roller 64 is eccentrically mounted on its shaft 68. This is best shown in detail in FIG. 3 which illustrates one end portion of the shaft 68. It will be understood that the other end is substantially correspondingly constructed. As shown in detail in FIG. 3, a bushing 76 is mounted in an opening in side frame 20 and is fastened to the side frame by screws 78. The shaft 68 has enlarged portions 80 at its ends which are rockable within the bushings 76. The shaft 68 is formed so as to embody an elongate eccentric middle portion 82 extending between the enlarged portions 80 upon which the roller 64 is rotatably supported. An operating handle 84 is provided which, with knob 86, is aflixed to one end of the shaft 68 by means of a screw or pin 88. To hold the shaft 68 in proper endwise position, there is provided at one end a screw 90. As shown in FIG. 3, the screw 90 is mounted in the bushing 76, the head of the screw engaging in a groove 92 in the knob 86.

Referring to FIG. 4, it will be noted that when the handle 84 is in operating position (in this instance as shown in its vertical position), the rollers 62, 64 are substantially in contact with each other; and when the handle is in non-operating position (in this instance at 90, as shown in broken lines), the rollers are separated from each other. This eccentric movement serves to insure that the transfer roller 64 will adequately supply pre-dampening solution or liquid to a duplicating master when in its operative position, and that the rollers 62 and 64 are separated when not in use, thus preventing the possibility of a lineal flat occurring on roller 64 at the point of contact between the two rollers. Suitable means may be provided if desired to adjustably limit the throw of handle 84 so as to permit the operator to set the degree of proximity between rollers 62 and 64.

Having thus described the structure of the master feeding and predampening device of this invention, attention is directed to FIG. 2 for a description of the operation of the device.

In operation, a duplicating master 24 is fed from the bottom of the supply of masters by a feed roller or segment 94, which is driven by a one-revolution clutch 96. Both the feed roller 94 and clutch 96 are mounted on a shaft 98, which is journalled in side frames 20.

Whenever the one-revolution clutch 96 is tripped, the feed roller 94 is caused to rotate in a clockwise direction, as viewed in FIG. 2, and the lowermost master 24 is thereby fed away from the feed table 22 and through the space provided below the lower edge 38a of the vertical portion 38 of the separating and deflecting means 36. As the master 24 continues on its travel, the leading edge of the master engages the deflector 42 and is thus guided onto a guide plate 100 and thence into the bight of the intermediate feed rollers 44 and 46. Continuing on, the master 24 is fed onto a feed table 102 which also acts as a guide to permit the master 24 to enter into the bight of fountain roller 62 and dampening or transfer roller 64.

It is at this point in operation of the device that its novel aspects become especially apparent. By way of explana tion, attention is directed to FIG. 1 wherein there is shown a bead or wedge B of pre-dampening solution or liquid 70. Thus, when no master is being fed the predampening solution is fed by the roller 62 to a line of contact between the rollers 62 and 64, forming the visible liquid bead or wedge B which is maintained at the line of contact of the rollers by the surface tension of the solution or liquid and the friction of the surfaces of the rapidly rotating rollers.

Referring to FIG. 2, there is disclosed the formation which includes two liquid beads or wedges B and B". This is brought about by reason of the passing of a duplicating master between the rollers 62 and 64. Thus, when the lead edge of a master is guided between the rollers 62, 64- it comes in at such a level that it scoops under the major portion of the bead B and traps the liquid thereof against the upper surface of the master. This then becomes the upper bead B" which sweeps across the master surface as it is fed forward, such bead becoming gradually depleted as the moisture is taken up by the surface of the master sheet. It has been found however that an adequate supply is provided to treat the entire surface of masters of any of the usual lengths. While the master is being fed through in this manner, the liquid or solution 70 is also being carried upwardly by the fountain roller 62 to form liquid bead B. Passage of the liquid is arrested as it comes in contact with the bottom of duplicating master 24 and any excess liquid merely returns to the fountain 72.

The foregoing operation takes place essentially as described whether the roller 64 is hard-surfaced or covered with a compressible absorptive material such as molleton cloth. If the latter arrangement is used, there is probably also a certain reservoir action resulting, since the intervention of the master 24 causes the absorbent cover 74 on roller 64 to become compressed at the line of contact 64a with the master, thus bringing about a wringing out action and causing a replenishment of the liquid bead B". This formation of liquid bead B" on the upper surface of the master is of primary importance in the satisfactory performance of the device of this invention. For example, as a duplicating master 24 passes between rollers 62 and 64, the liquid bead B is formed so as to overlie the top surface of the master. This is extremely important since the top surface of the master bears the image which is to be reproduced and accordingly is the one which must be treated. With this in mind, it is pointed out that as the master 24 travels between rollers 62 and 64 the liquid bead or wedge B is forced onto the imagecarrying surface of the master in a continuous line transversely of the master and in a continuous uniform, ironing-out manner in relation to forward movement of the master.

The primary reason for using the soft cover 74 is that it shows a marked tendency to resist clinging of the master and provides a ready release at the exit side of the roller pair 62, 64. The pre-dampening solution 70 which is transferred to the master 24 from the cover 74, when the same is used, will be quickly replenished by continued rotation of rollers 62 and 64 when no duplicating master is present between them, as for example, when copy sheets are being run on the associated duplicating machine, not shown. This provides a necessary idle period which always occurs prior to dampening of the next master to be run.

Following completion of the pre-dampening of the master 24, it is brought to rest on a table .104 so as to there be available for attachment to a printing drum or master cylinder MC at such time as a used master is expelled from the duplicating machine and a newly dampened master 24 is required for the start of a new run of duplicated copy sheets.

As will be readily apparent, no time is lost in performing the operation of dampening, or pre-dampening, planographic duplicating masters according to the principles taught by this invention. Thus, a master may be dampened at the will of the duplicating machine operator, or the master may be fed during any pre-determined cycle of operation of the machine, without interruption of operation and while copy sheets are being duplicated from a previously dampened master.

Any conventional means for driving the rollers 44, 46 and 62, 64 may be employed. In the situation where the rollers 62, 64 are provided with surfaces having friction-a1 driving properties (e.g. rubber or the like) it is considered preferable for the pairs of rollers 44, 46 and 62, 64 to have equal peripheral speed in order that the duplicating master 24 will glide uninterruptedly and without stress along its entire path of travel. If the rollers 62, 64 should be revolving at slightly greater speed than rollers 44, 46 this compound roller rotation action might result in a simation whereby rollers 62, 64 could skid against the duplicating master resulting in an impairment of the image. However, as a practical matter, if rollers 62, 64 are rotating at a peripheral speed slightly slower than rollers 44, 46, the skidding action referred to above will not occur. At most, under such a condition the duplicating master 24 may tend to buckle slightly at the point of contact between rollers 62, 64 until such time as the master leaves the bight of rollers 44, 46. However, any buckling which occurs is of no consequence and would normally be preferable to the skidding action described here-inabove.

While the form of the invention shown and described I herein is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the form disclosed here-in, for the invention is susceptible of embodiment in other for-ms and variations. It will be understood, therefore, that the invention is claimed in any of its forms or modifications falling within the spirit and scope of the language employed in the appended claims.

What is claimed is:

1. A device for applying pre-dampening liquid to a duplicating master with its active surface in upwardlyfacing position and forwarding the same to a duplicating machine, comprising a fountain for containing the predampenin-g liquid; a fountain roller dipping into a bath of pre-dampening liquid when placed in the fountain; means for rotating the fountain roller to move its upper surface in a predetermined direction; a transfer roller above and adjacent said fountain roller and effective when operated in conjunction with the fountain roller to form therewith a preliminary bead of pre-dampening liquid at the bight of said rollers; means for advancing a master into the bight of said rollers in said predetermined direction; a feed table for holding a supply of masters; means for separating a single master and forwarding it to said advancing means; means for guiding the advancing master at a level such that the leading edge divides the preliminary bead when formed by said rollers and traps the major portion thereof above itself to form an upper bead lying against the upper surface of the master and swept thereacross as the master is fed between the rollers; and a master receiving table adjacent the master cylinder of the duplicating machine to which the master is fed by the dampening rollers to rest in a ready position until attachment to the master cylinder is effected.

2. A device for applying pre-dampening liquid to a duplicating master with its active surface in upwardlyfacing position, comprising a fountain for containing the pre-dampening liquid; a fountain roller dipping into a bath of pre-da-mpening liquid when placed into the fountain; means for rotating the fountain roller to move its upper surface in a predetermined direction; a transfer roller above and adjacent said fountain roller and effective when operated in conjunction with the fountain roller to form therewith a preliminary bead of pre-dampening liquid at the bight of said rollers; a feed table for holding a supply of masters; means for separating a single master and forwarding it into the bight of said rollers in said predetermined direction; means for guiding the master at a level such that the leading edge divides the preliminary head when formed by said rollers and traps the major portion thereof above itself to form an upper bead lying against the upper surface of the master and swept thereacross as the master is fed between the rol lers; and a master receiving means adjacent the master cylinder of a duplicating machine to which the master is fed by the dampening rollers in position for attachment to the master cylinder.

References Cited by the Examiner UNITED STATES PATENTS 617,720 1/1899 Cowles 15-102 1,035,242 8/1912 Russell 118-227 X 1,867,594 7/1932 Rowe 118--227 2,674,222 4/ 1954 Messinger et al. 118-249 X 3,098,249 7/1963 Tice et al. 154

CHARDES A. WILLMUTH, Primary Examiner. L. G. MACHLIN, Assistant Examiner.

Claims (1)

1. A DEVICE FOR APPLYING PRE-DAMPENING LIQUID TO A DUPLICATING MASTER WITH ITS ACTIVE SURFACE IN UPWARDLYFACING POSITION AND FORWARDING THE SAME TO A DUPLICATING MACHINE, COMPRISING A FOUNTAIN FOR CONTAINING THE PREDAMPENING LIQUID; A FOUNTAIN ROLLER DIPPING INTO A BATH OF PRE-DAMPENING LIQUID WHEN PLACED IN THE FOUNTAIN; MEANS FOR ROTATING THE FOUNTAIN ROLLER TO MOVE ITS UPPER SURFACE IN A PREDETERMINED DIRECTION; A TRANSVER ROLLER ABOVE AND ADJACENT SAID FOUNTAIN ROLLER AND EFFECTIVE WHEN OPERATED IN CONJUNCTION WITH THE FOUNTAIN ROLLER TO FORM THEREWITH A PRELIMINARY BEAD OF PRE-DAMPENING LIQUID AT THE BIGHT OF SAID ROLLERS; MEANS FOR ADVANCING A MASTER INTO THE BIGHT OF SAID ROLLERS IN SAID PREDETERMINED DIRECTION; A FEED TABLE FOR HOLDING A SUPPLY OF MASTERS; MEANS FOR SEPARATING A SINGLE MASTER AND FORWARDING IT TO SAID

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