US3433155A

US3433155A - Mechanism for applying a coating to a plate

Info

Publication number: US3433155A
Application number: US486680A
Authority: US
Inventors: Robert K Norton
Original assignee: Harris Intertype Corp
Current assignee: Harris Graphics Corp
Priority date: 1965-09-13
Filing date: 1965-09-13
Publication date: 1969-03-18
Anticipated expiration: 1986-03-18
Also published as: DE1536450B2; DE1536450C3; GB1163267A; DE1536450A1

Description

March 18, 1969 R. K. NORTON 3,433,155

MECHANISM FOR APPLYING A COATING TO A PLATE 7 Filed Sept. 13, 1965 Sheet of 2 INVENTOR.

ROBERT K. NORTON ATTORNEYS March 18, 1969 R. K. NORTON 3,433,155

' MECHANISM FOR APPLYING A comma TO A PLATE Filed Sept. 13, 1965 Sheet 2 of 2 R R I BYOBE T K NORTON ATTORNEYS United States Patent 8 Claims ABSTRACT OF THE DISCLOSURE A dampening mechanism for applying a dampening fluid to the surface of a rotating printing plate of a printing press is disclosed. The dampening mechanism comprises a form roll driven by the printing plate, a hard surface, hydrophilic roll for transferring dampening fluid to the form roll, a resilient metering roll running in pressure engagement with the hydrophilic roll for transferring the dampening fluid to the hydrophilic roll and a resilient pan roll for transferring dampening fluid from a supply to the metering roll. The hard surface, hydrophilic roll is positively rotated to have the same surface speed as the rotating printing plate and the resilient metering roll is driven at a speed which is adjustable to adjust the relative surface speeds between the hard surface, hydrophilic roll and the resilient metering roll to control the amount of dampening fluid delivered to the hydrophilic roll.

The present invention relates to a printing press or other apparatus in which a rotating applicator such as a form roll applies a fluid material, e.g., ink, dampening fluid, or both, to the surface of a printing plate or the like.

An important object of the present invention is to provide a new and improved lithographic printing press having a dampening mechanism in which the flow of dampening fluid is controlled by varying the relative surface speed of cooperating rolls in the dampening mechanism and in which the dampening mechanism includes a positively driven roll which runs in engagement with a form roll, the driven roll being driven at the surface speed of the plate to minimize the effect of scumming on the plate.

Another object of the present invention is to provide a new and improved lithographic printing press wherein the printing plate has dampening fluid applied thereto by a form roll frictionally driven from the plate with dampening' fluid being supplied to the form roll from a positively driven hard surface transfer roll whose surface speed is the same as the surface speed of the plate cylinder and in which the dampening fluid on the hard surface transfer roll is controlled by varying the speed of a resilient surface running in pressure engagement with the hard surface transfer roll.

Another object of the present invention is to provide a new and improved lithographic printing press in which dampening fluid being fed to the printing press is first metered by a roll running in pressure relationship with a variable speed roll having a resilient surface with the amount of fluid being transferred by the dampening mechanism being controlled by varying the speed of the variable speed roll to vary the surface speed between the variable speed roll and a positively driven hard surface hydrophilic roll rotating at a predetermined surface speed, preferably at the surface speed of the plate.

Still another object of the present invention is to provide a new and improved lithographic printing press in which a dampening mechanism for feeding dampening fluid to the :printing press has the dampening fluid metered and smoothed out by a resilient surface roll which operates as a pan roll and delivers dampening fluid to a cooperating roll having a resilient surface with the surface speed of the cooperating roll and the pan roll being the same but variable to vary the amount of dampening fluid transferred to a hard surface roll running in pressure engagement with the cooperating roll and having a predetermined surface speed.

Yet another object of the persent invention is to provide a new and improved printing press in which a dampening fluid is transferred by a plurality of rolls from a supply therefor to a printing plate and wherein the distribution and amount of dampening fluid is controlled by varying the speed of a roll having a resilient surface to change its surface speed relatively to a hard surface roll with which it has a pressure engagement.

The present invention also contemplates the provision of a new and improved apparatus embodying at least three rolls for feeding fluid material to a rotating applicator in which apparatus a first resilient surface roll controls the transfer of fluid material to a second resilient surface roll which runs in pressure relationship therewith with the surface speed of the resilient surface rolls being the same but variable relative to the speed of a hard surface transfer roll which receives the material from the variable speed transfer roll.

A still further object of the present invention is to provide a new and improved apparatus for applying a coating of fluid material to a moving surface in which a rotating applicator roll for applying the coating is rotated at a surface speed of the moving surface by frictional engagement of the moving surface and by the frictional engagement of roll means running in contact with the periphery of the applicator roll, and in which fluid material is supplied to the applicator roll from a supply therefor by a plurality of rolls including one running at a surface speed different from the surface speed of the moving surface, the plurality of rolls being arranged and driven in a manner such that there is little or no tendency of the applicator roll to slow when not engaged with the moving surface due to the drag of the roll which runs at a different surface speed.

Further objects and advantages of the present invention will be apparent from the following detailed description thereof made with reference to the accompanying drawings forming a part of the present specification and in which:

FIG. 1 is a diagrammatic view showing a portion of a printing press embodying the present invention;

FIG. 2 is a view which corresponds to a portion of FIG. 1 showing certain parts thereof in different positions;

FIG. 3 is a view, somewhat diagrammatic, of a drive for one of the dampening rolls of the apparatus shown in FIG. 1;

FIG. 4 is an enlarged view showing the relationship of three of the dampening rolls of the apparatus shown in FIG. 1;

FIG. 5 is a fragmentary view showing a bearing mounting for one of the rolls of the apparatus shown in FIG. 1;

FIG. 6 is a view taken from approximately line 6-6 of FIG. 5 looking in the direction of the arrows;

FIG. 7 is a view with certain parts omitted looking approximately from line 77 of FIG. 1 in the direction of the arrows; and

FIG. 8 is an elevational view of two of the rolls of the apparatus of FIG. 1 with one of the rolls having a modified structure.

The present invention is susceptible for use in various machines where it is desirable to apply a coating of a fluid material onto a moving surface with an applicator roll or other type of rotating applicator but it is particu larly useful to apply dampening fluid to the surface of a printing press plate cylinder.

In a lithographic offset printing press, ink and dampening fluid are applied to the printing plate and in the illustrated press, ink is fed to the printing plate through an inking mechanism which includes

form rolls

16, 17, 18, 19 which run in engagement with the surface of the printing plate. A vibrating roll 20 is disposed between the

form rolls

16, 17 and runs in engagement therewith while a similar vibrator roll 21 engages and runs in contact with form rolls 1'8, 19. A vibrator roll 22 also engages

form rolls

17, 18. The

vibrating rolls

20, 21, 22 are conventional vibrator rolls having a hard smooth ink receptive metal surface while the form rolls 16, 17, 18 and 19 have conventional resilient surfaces. The ink is fed to the vibrator rolls 20, 21 from an ink fountain 24 by a duct roll 25 and a plurality of ink transfer rolls shown in the drawing. The train of ink rolls shown for supplying ink to the form rolls is that of a conventional inker and therefore will not be described in detail.

In accordance with the preferred and illustrated embodiment, dampening fluid is applied to the plate on the cylinder by a dampening mechanism which feeds the dampening fluid through the first form roll 16 which is larger than the other form rolls. The dampening mechanism includes roll 28 having a hard hydrophilic, smoothly finished surface, preferably chrome, which rotates in pressure relationship with the first form roll 16, a resilient surface variable speed roll 30 which runs in pressure relationship with the hard chrome roller 28 and a cooperating metering roll 31 having a resilient surface and rotating in a pan 32 containing the dampening fluid. The metering pan roll 31 picks up dampening fluid from the pan 32, transfers it to the roll 30, which in turn transfers the dampening fluid to the chrome transfer roll 28 running in engagement with the first form roll 16 to feed the dampening fluid to the form roll and from the form roll 16 to the plate. To control the amount of dampening fluid being transferred between the pan 32 and the form roll, the roll 30 is driven at a speed which is variable to vary the relative surface speeds of the metering roll 30 and the chrome transfer roll 28. The variable speed metering roll 30 and the metering pan roll 31 are driven to rotate at the same surface speed. Consequently, the metering pan roll 31 is rotated at the same surface as the metering roll 30 but this surface speed is variable to control the amount of fluid transferred between the roll 30 and the roll 28 which rotates at a fixed surface speed for a given press speed. The

rolls

28, 30 and 31 each preferably rotate in an opposite direction to the roll or rolls which it engages, but the

rolls

30, 31 may be driven so that the roll 30 rotates in the same direction as the chrome roll 28.

In the preferred mechanism the chrome transfer roll 28 is positively driven from the plate cylinder and is rotated at the same surface speed as the plate cylinder. The vibrator roll 20 is also positively driven from the press at the same surface speed as the plate cylinder in a conventional manner and the form roll 16 is frictionally driven from the vibrator roll 20, the chrome transfer roll 28 and the plate cylinder. In the illustrated arrangement, the chrome transfer roll 28 is shown as being driven from a gear 33 which is on the plate cylinder and rotates therewith. The gear 33 drives a gear 34 which drives a shaft 37 through

bevel gears

35, 36. The shaft 37 is connected by

bevel gears

38, 39 to drive a shaft 40 which in turn drives a shaft 41 through a clutch 42. The shaft 41 has a bevel gear 43 thereon which meshes with a bevel gear 44 on the shaft of the transfer roll 28. The spline connection of the gear 43 allows the transfer roll 28 to be moved into and out of engagement with the form roll 16 while maintaining a drive thereto. The chrome roll is preferably driven at the surface speed of the plate cylinder to frictionally drive the form roll 16 at this speed to thereby prevent any drag on the form roll which may occur when a roll which runs in engagement therewith rotates at a slower surface speed. In mechanisms where the dampeni g roll running in en- .4 gagement with the form roll is driven at a slower speed, there is a frictional drag on the form roll which tends to slow the form roll as the gap which is present in conventional plate cylinders passes the form roll. I have found that this may cause a scumming or smudging on the lead edge portion of the printing plate. By providing a dampening mechanism where the roll of the dampening mechanism in engagement with the form roll is positively driven at the surface speed of the plate cylinder, this tendency of the slower speed roll 30 to effectively brake the form roll is overcome or minimized.

The variable speed metering roll 30 is driven by a variable speed motor 45 through a positive drive shown as a chain drive 45a. A chain drive 45b may also be used to drive the metering roll 31 from the roll 30 to rotate them in a 1 to 1 relationship so that they have the same surface speeds.

In the described mechanism, the chrome transfer roll 28 and the form roll 16 are of the same length but the metering roll 30 is longer than the chrome transfer roll 28 so as to extend beyond the opposite ends thereof.

The pressure relationship between the metering pan roll 31 and the metering roll 30 is adjustable to smoothly meter the flow of dampening fluid between the nip of the rolls to provide an evenly distributed thin film of dampening fluid on the roll 30. The pan metering roll 31 preferably has shaft portions extending from the opposite ends thereof to be supported in bearing blocks which may be moved toward and away from the metering roll 30 to adjust the pressure relationship between the

rolls

30, 31. Bearing blocks of this type are conventional and well known in the art and a simplified bearing support for the roll 31 is shown in FIG. 5. As shown in FIG. 5, the shaft portion 31a extending from one end of the roll 31 is received in a self-centering bearing 46a in a bearing block 46 which is supported in an inverted U-shaped recess in a guide block 47 mounted on a support member 48 of the frame F of the press. The open end of the U-shaped recess is closed by a plate 50 and a pressure adjusting bolt 50a is threaded through the plate 50 to engage the bearing block 46 and is adjustable to move the roll 31 upwardly into an adjustable pressure relationship with the roll 30. Preferably, the mounting block 47 is mounted onto the support member 48 by screws 47a which are received in elongated slots in the mounting block to allow the mounting block 47 and the bearing block 48 to be shifted laterally, i.e. horizontally, to adjust the axis of the roll 31 to provide a skewed relationship relative to the roll 30. The mounting block 47 is shown as being adjustable laterally by the operation of a plurality of adjusting screws 51. Since the metering pan roll 31 is supported at both ends by the same type of support the metering roll 31 can be moved to a skewed position relative to the roll 30 as is best shown in FIG. 7. The bearings 46a at each end of the roll 31 pivot in the respective block 46 to accommodate the skewing of the re A skewed position for the metering roll 31 is advantageous to obtain a thin evenly distributed film on the roll 31. When a pressure relationship is established by applying forces to the shaft portions at the opposite ends of the metering roll 31, the roll tends to bow outwardly in the center portion of the roll and to allow more dampening fluid to pass the center portion of the roll than the ends of the roll. By skewing the axis of the

rolls

30, 31, an even pressure relationship along the area of contact can be obtained since bowing the roll is required to provide an even contact when the rolls are skewed.

The roll 31 may be a crowned roller as indicated in FIG. 8. In FIG. 8, the roll '31 tapers in an arcuate manner from the central portion thereof to the ends so that when the pressure relationship is established between the

rolls

30, 31, the rolls engage over an area of substantially constant width. Preferably, the area of contact is a narrow strip extending the length of the

rolls

30, 31.

The exact extent of the crown may be determined empirically and varies in accordance with the length of the roll and its strength and in accordance with the materials involved. A crowned roll may be used in combination with skewing or in lieu of skewing.

The resilient roll 30 and the chrome roll 28 also run in pressure relationship and this relationship may be adjustable by the use of movable bearing blocks similar to those on the roll 31.

As indicated by dotted lines in FIG. 1, the form rolls 17, 18 and 19 are supported for movement to an inker off position in a conventional manner while the form roll 16 is moved from its position against the plate by operation of the dampening mechanism. The dampening mechanism as a whole is supported for movement toward and away from the cylinder to move the chome roll 28 into and out of engagement with the form roll 16. A roller 55 on a pivoted actuating arm 56 may be swung to the position shown in FIG. 1 to move the dampening mechanism from the position shown in FIG. 2 to establish the pressure relationship between the relative positions of the chrome roll 28 and the form roll 16 shown in FIG. 1. The roller engages an adjustable plate 57 on the dampening mechanism to move the latter against the action of a spring 60. Stops 61, 62 may be provided to limit the movement of the arm between the inker on and inker olf position. In its on position, the pivoted arm 56 is in a dead center or locking position slightly over dead center. Adjustment of the plate 57 determines the on position of the dampener and the pressure relationship between the

rolls

16, 28.

When the vibrating roll 28 is to be moved out of engagement with the form roll 16, the arm '56 is rotated to allow the dampening mechanism to be moved away from the impression cylinder by the spring 60.

In the illustrated embodiment, the form roll 16 is mounted for limited movement about the axis of the vibrator roll 20. When the dampening mechanism is moved to clear the chrome roll 28 from the form roll 16, the form roll is moved by a spring 65 against a stop 66 to move the form roll out of engagement with the plate cylinder. When the dampening mechanism is again moved to its operative position, the chrome roll 28 engages the form roll 16 and moves it against the spring 65 to a position against the plate cylinder and against a stop 67 which limits the pressure that the form roll may apply to the plate cylinder and provides a resisting force to the chrome roll 28 to establish a pressure relationship between the chorme roll 28 and the form roll 16.

It can be seen that 'with the described construction, the

dampening mechanism can be operated when the mechanism is in its retracted position to form films on the rolls of the dampening mechanism and to cause the chrome roll 28 to be operating at press speed when it is moved into engagement with the form roll. It will be noted that the dampening mechanism can be moved to engage the form roll 16 with the chrome roll 28 rotating at the surface speed of the press, prior to the form roll engaging the plate. This enables the form roll 16 and the chrome roll 28 to be rotating at their proper speeds when the form roll 16 engages the plate. By positively driving the chrome roll 28, the chrome roll 28 will be driven at its proper speed when it is moved into engagement with the form roll 16 and the form roll 16 will be driven from both the vibrating roll 20 and the chrome roll 28. This will also keep the form roll 16 rotating at a surface speed corresponding to the surface speed of the plate cylinder when the gaps in the cylinder 10 are moving past the form roll 16.

It will be understood by those skilled in the art that the term hard surface roll as used in this specification includes a roll having an unyielding surface such as is commonly present on vibrator rolls and chrome hydrophilic rolls and is used to distinguish from other rolls commonly used in presses and which have a yieldable, resilient surface such as neoprene or rubber.

While the preferred embodiment and other embodiments of the present invention have been disclosed and described in detail, it is hereby my intention to cover all modifications, adaptations and arrangement of parts which fall within the ability of those skilled in the art and within the spirit of the appended claims.

Having described my invention, I claim:

1. In a lithographic printing press having a printing plate mounted on a rotatable plate cylinder with a gap therein, a dampening mechanism for supplying dampening fluid to an applicator roll running in engagement with a printing plate on the plate cylinder, a supply comprising a reservoir of dampening fluid for said plate, a hydrophilic roll running in rolling contact with said applicator roll, first drive means independent of the surface of said hydrophilic roll for positively driving said hydrophilic roll at the surface speed of said printing plate, means for delivering dampening fluid to said hydrophilic roll and forming an even film thereon comprising a resilient surface roll, first support means supporting said resilient surface roll to roll in engagement with said hydrophilic roll and for adjustment toward and away from said hydrophilic roll, second drive means apart from the surface of said resilient surface roll for driving said resilient surface roll at a surface speed which is adjustable independently of adjusting the speed of said hydrophilic roll to adjust the relative surface speeds of said resilient surface roll and said hydrophilic roll to control the amount of dampening fluid delivered to said hydrophilic roll, and means for delivering dampening fluid to said resilient surface roll and for metering the fluid delivered to form a thin evenly distributed film on said resilient surface roll comprising a pan roll which dips into said reservoir of dampening fluid, and second support means rotatably supporting said pan roll in continuous engagement with said resilient surface roll including means for adjusting the axis of said pan roll toward and away from said resilient surface roll separately from the adjustment of said resilient roll toward and away from said hydrophilic roll.

2. In a lithographic printing press having a printing plate mounted on a rotatable plate cylinder with a gap therein, a dampening mechanism for supplying dampening fluid to an applicator roll in running engagement with the printing plate on the rotating plate cylinder, a supply of dampening fluid, a hydrophilic roll running in rolling contact with said applicator roll, said hydrophilic roll having a hard unyieldable hydrophilic surface, drive means independent of the surface of said hydrophilic roll for positively driving said hydrophilic roll at the surface speed of said printing plate, means for delivering dampening fluid to said hydrophilic roll and forming an even film thereon comprising a resilient surface roll, means supporting said resilient surface roll to run in engagement with said hydrophilic roll with the axes of said hydrophilic roll and said resilient surface roll being spaced generally horizontally from each other, said means supporting said resilient surface roll comprising adjustable means for adjusting the distance between the axes of said hydrophilic roll and said resilient surface roll to adjust the pressure relationship therebetween, a metering pan roll disposed generally vertically below said resilient surface roll, means supporting said pan roll for rotation and running engagement with said resilient surface roll including means for adjusting the axis of said pan roll vertically to adjust the pressure relationship between said pan roll and said resilient surface roll, a pan providing a reservoir of fluid in which the lower portion of said pan roll runs, and means for driving said pan roll and said resilient surface roll at the same speed which is slower than the surface speed of the plate cylinder.

3. In a lithographic printing press, a dampening mechanism as defined in claim 2 wherein said supporting means for said pan roll comprises adjustable bearing supports for adjusting the axis of said support roll horizontally to skew the roll with respect to the resilient surface roll and vertically to urge the skewed pan roll into uniform pressure engagement with said resilient surface roll for substantially the entire length of the rolls.

4. In a lithographic printing press as defined in claim 2 wherein said pan roll comprises a roll having a diameter which progressively decreases proceeding from the center toward each end to compensate for deflection of said shaft means on the establishment of a pressure relationship between pan roll and said resilient surface roll.

5. In a lithographic printing press, a dampening system for supplying fluid to a form roll running in engagement with the plate cylinder comprising a pan containing a reservoir of dampening fluid, a pan roll having its lower portion running in the reservoir of dampening fluid, a resilient surface roll disposed above the pan roll and running in engagement therewith, said pan roll having shaft means projecting outwardly from each end thereof, bearing means supporting said shaft means including means for adjusting said shaft means horizontally to skew said pan roll relative to said resilient surface roll and means for adjusting said shaft means vertically to adjust the pressure relationship between said resilient surface roll and said pan roll, and a third roll running in liquid transfer relationship with said resilient surface roll with the axis of said third r011 being disposed generally horizontally from the axis of said resilient surface roll, drive means separate from the surface of said third roll for driving said third roll at a fixed speed, motor means connected to one of said pan and resilient rolls separately from the surface thereof to drive said pan and resilient surface rolls at the same surface speed and at a speed slower than the speed of said third roll.

6. In a lithographic printing press as defined in claim 5 wherein the press includes means supporting said rolls to move said third roll into and out of engagement with said form roll while running in engagement with each other, said drive means for driving said third roll and said motor means being operable to drive the corresponding rolls when said third roll is clear of said form roll and when in engagement with the latter.

7. In a lithographic printing press, a dampening system for supplying fluid to form a roll running in engagement with the plate cylinder comprising a pan containing a reservoir of dampening fluid, a pan roll having its lower portion running in the reservoir of dampening fluid, a resilient surface roll disposed above the pan roll and running in engagement therewith, said pan roll having shaft means projecting outwardly from each end thereof, bearing means supporting said shaft means including means for adjusting said shaft means vertically to adjust the pressure relationship between said resilient surface roll and said pan roll, and a third r011 running in liquid transfer relationship with said resilient surface roll with the axis of said third roll being disposed generally horizontally from the axis of said resilient surface roll, drive means separate from the surface of said third roll for driving said third roll at a fixed speed, motor means connected to one of said pan and resilient rolls separately from the surface thereof to drive said pan and resilient surface rolls at the same surface speed and at a speed slower than the speed of said third roll, said pan roll comprising a roll having a diameter which progressively decreases proceeding from the center toward each end to compensate for deflection of said shaft means on the establishment of a pressure relationship between pan roll and said resilient surface roll.

8. In a lithographic printing press, a dampening system for supplying fluid to a form roll running in engagement with the plate cylinder comprising a pan containing a reservoir of dampening fluid, a pan roll having its lower portion running in the reservoir of dampening fluid, a resilient surface roll disposed above the pan roll and running in engagement therewith, said pan roll having shaft means projecting outwardly from each end thereof, bearing means supporting said shaft means including means for adjusting said shaft means horizontally to skew said pan roll relative to said resilient surface roll and means for adjusting said shaft means vertically to adjust the pressure relationship between said resilient surface roll and said pan roll, and motor means connected to one of said pan and resilient rolls separately from the surface thereof to drive said pan and resilient surface rolls at the same surface speed and at a speed slower than the surface speed of said form roll.

References Cited UNITED STATES PATENTS 1,419,189 6/1922 Wood 101-350 1,755,278 4/ 1930 Strain.

2,580,667 1/1952 Faeber et a1 101-365 X 2,689,522 9/1954 Curtis 101-148 X 2,732,591 1/1956 Whittum.

3,106,154 10/1963 Saul 101-350X 3,168,037 2/1965 Dahlgren 101-148 3,280,733 10/1966 Jurny 101-147 2,102,641 12/1947 Osborn 101-148 2,762,295 9/ 1956 Varga et a1 101-148 XR 2,821,132 1/1958 Brodie 101-148 XR FOREIGN PATENTS 870,687 6/ 1961 Great Britain.

EDGAR S. BURR, Primary Examiner.

U.S. Cl. X.R.