Printing plate mounting device and method

A mounting device and method for positioning a printing plate on a press cylinder utilizes a transparent planar surface having a grid thereon. A cylinder can be lowered into the cradle and adhesively retain a flexible printing plate which has been alinged on the grid. The method employed provides an efficient time saving and accurate mounting process.

BACKGROUND OF THE INVENTION 
1. Field Of The Invention 
The invention herein pertains to printing and particularly to the mounting 
of flexographic printing plates on printing press cylinders. 
2. Description Of The Prior Art And Objectives Of The Invention 
In recent years many advances have been made in printing techniques and 
specifically in printing such as in the use of resilient polymer printing 
plates, hereinafter referred to as flexographic plates. Various techniques 
and devices have been tried in order to promptly mount such printing 
plates on press cylinders to insure that the plate is properly aligned. 
Misalignment of course can cause tremendous waste and expense and with the 
use of high speed presses with multiple printing cylinders, even one 
cylinder having a misaligned plate can cause extensive press downtime and 
wasted time and materials. Special measuring instruments have long been 
employed to insure correct plate alignment on the press but oftentimes, 
even with sophisticated instrumentation, registration is not achieved. One 
plate which is a fraction of an inch out of register can completely 
destroy a multicolor press run and result in the loss of hundreds or more 
dollars. Thus, techniques have been long sought in the printing industry 
to insure quick and correct plate positioning on the press cylinders. 
The present invention was thus conceived with the disadvantages known of 
conventional plate alignment devices and methods and one objective of the 
present invention is to provide a mounting device for positioning a 
printing plate on a press cylinder which is simple to use and accurate in 
its results. 
It is another objective of the invention herein to provide a mounting 
device which is relatively easy to learn to use and which is inexpensive 
to purchase. 
It is another objective of the present invention to provide a mounting 
device which can be utilized by those with relatively little experience in 
the printing trade for a variety of printing plates. 
It is also an objective of the plate invention to provide a method for 
mounting one or more printing plates on plate supports which will require 
little time and which will insure accurate plate alignment on the press. 
Other advantages and benefits of the invention will become apparent to 
those skilled in the art as a more detailed description is presented 
below. 
SUMMARY OF THE INVENTION 
The aforesaid and other advantages of the present invention are realized by 
providing in one embodiment a mounting device which includes a base having 
a transparent surface. A printed grid is placed over the transparent 
surface and mounted thereto is a printing press cylinder cradle. The 
cradle is attached to the base whereby a press cylinder is positioned in 
the cradle and is directed downwardly to the printing plate placed face 
downwardly on the grid. The tacky outer surface of the cylinder adheres 
the plate to the cylinder. As the ends of the cylinder cradle are aligned 
on the grid, by aligning the plate on the grid, a correctly positioned 
plate on the press cylinder is assured. Another embodiment of the mounting 
device includes a tape supply and apparatus for accurately cutting the 
tape for easy application to the printing cylinder. A plate shelf may be 
utilized for insertion and expulsion of a plate support having a plate 
mounted thereon through the mounting device. A stacking frame allows for 
accurate alignment of multiple printing plates. 
The method of the invention includes directing the press cylinder within 
the cradle into contact with the printing plate to touch its adhesive or 
tacky outer surface. By rotating the cylinder, the plate is then securely 
wrapped around the cylinder while the plate supports exits the mounting 
device and thereafter the cylinder with the attached plate is removed from 
the cradle and can be installed on the printing press for printing. A 
method of aligning a plurality of printing plates each on individual plate 
supports on a light table within a stacking frame is also described.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The preferred form of the apparatus of the invention is seen in FIG. 5 with 
a tape supply and a tape cutting panel. A cylinder cradle includes a pair 
of slotted vertical planar end members with horizontal supports attached 
between the ends. The lower horizontal supports allow a plate support with 
a printing plate taped thereto to to be slid into and through the mounting 
device and simultaneous attachment of the plate to the plate cylinder. 
Tension is applied to one edge of the plate support as it passes through 
the mounting device. 
The preferred method of the invention includes positioning a plate face 
downward onto the grid of a plate support. By directing the press cylinder 
into the cradle formed by the planar end members, the cylinder which has 
an adhesive outer surface can contact the back of the printing plate. 
Thereafter, by rotating the cylinder within the cradle the printing plate 
will wrap around the cylinder as the plate support exits the mounting 
device and the cylinder can thereafter be removed and placed on a press 
for printing. One or more printing plates can be aligned on subsequent 
transparent plate supports positioned on a light table within a stacking 
frame and upon removal therefrom, the printing plates can be attached to 
printing press cylinders as described above. 
DETAILED DESCRIPTION OF THE DRAWINGS AND OPERATION OF THE INVENTION 
Mounting device 10 is shown in top perspective view in FIG. 1 with press 
cylinder 11 positioned slightly above. Cylinder 11 may be for example, 
sixteen (16) inches in length. Device 10 includes planar ends 12 
vertically mounted on base 13 which consists of a transparent material 
such as glass or a synthetic substance such as an acrylic plastic. 
Adhesively affixed to the top surface of base 13 is grid 14 which may be 
for example a thin clear transparent plastic sheet with black printed 
lines 15 thereon. Lines 15 are perpendicularly arranged and may form 1/4 
inch squares. Ends 12 are attached to base 13 by bolts (not shown) or the 
like to provide a firm attachment to base 13 and grid 14. Ends 12 and 
horizontal supports 16 form cylinder cradle 17 and by positioning cylinder 
11 therein, cylinder 11 is "square" with grid 14. As seen in FIG. 1, ends 
12 include a vertical slot 18 and as further seen in FIG. 3, cylinder axle 
bearings 19 slide into slots 18 with the depth of penetration terminated 
by adjusting means 20 (FIG. 1). Adjusting means 20 is threadably received 
in planar end 12 through threaded aperture 21. Adjusting means 20 allows 
cylinder 11 to be inserted into contact with plate 22 at adhesive section 
23. As would be understood, plate 22 is a transparent, flexible printing 
plate formed from a conventional polymer substance and is made of 
sufficient thickness as specific requirements dictate. Section 23 may 
consist of an adhesive pad which is attached to cylinder 11 or may consist 
of an adhesive substance applied directly to the outer surface of cylinder 
11. As cylinder 11 is directed downwardly into slots 18, adjusting means 
20 on each side of cradle 17 are set so that the outer surface of cylinder 
11 just touches printing plate 22 which is aligned face downwardly on grid 
14. Once printing plate 22 is in adhesive contact with cylinder 11, 
cylinder 11 can be rotated in cradle 17 and plate 22 can then be 
completely wrapped therearound. 
In FIG. 4 legs 25 are shown attached to base 13 to form table 26 for 
supporting cradle 17. Other configurations of mounting device 10 could be 
designed so base 13 could then be positioned thereon. It has been found 
that by forming base 13 omitted part could then be placed thereunder to 
assist in the alignment of plate 22 on grid 14. As hereinbefore stated 
plate 22 is first aligned on grid 14 and thereafter, press cylinder 11 is 
directed downwardly within cylinder cradle 17 until slight contact is made 
between the outer surface of cylinder 11 and plate 22. Once contact with 
cylinder 11 has been made, cylinder 11 is rotated within cradle 17 until 
plate 22 is completely adhered to the outer surface of cylinder 11. 
Thereafter, cylinder 11 with plate 22 affixed is removed from cradle and 
is placed on the printing press (not shown) for the usual printing 
procedures. 
By another method it may be only necessary to raise press cylinder 11 
within its mounting on the press and place grid 14 thereunder. Printing 
plate 22 could then be placed face downwardly on grid and cylinder 11 
lowered into contact with the plate whereupon plate 22 can then be wrapped 
around cylinder 11 as earlier described with cradle 17. By this 
abbreviated process, press cylinder 11 does not have to be removed from 
the printing press and plates can be mounted on the press by simply 
raising cylinder 11 from its normal engaged press position. This method of 
course would only apply to most presses which have adjustable cylinder 
mountings thereon. 
A second embodiment of the mounting device is shown in FIG. 5 with plate 
mounting device 30 which includes an adhesive tape supply 32 in the form 
of a double sided tape roll having a peel-off release paper on one side. 
Cylinder 45 can be bearingly mounted in device 30 by placing axle hubs 46 
thereon and positioning hubs 46 in shallow slots 47 in planar members 48. 
Tape supply 32 is then unrolled for placing on printing cylinder 45 by 
wrapping therearound with the exposed adhesive side against cylinder 45. 
Once the tape has been wrapped around printing cylinder 45, pivotal tape 
cutting guide 33 which is rotatably mounted in cutting guide slots 49 and 
includes cutting panel 36 is then rotated into contact with printing 
cylinder 45. A razor knife (not shown) is then pressed across the top of 
the tape and into cutting panel groove 37 which may be for example 1/16 of 
an inch in depth and a straight cut is thereby obtained to insure a smooth 
outer periphery of printing cylinder 45 as the ends of the tape should 
abut and not overlap. Thereafter the release paper is removed from the 
wrapped tape so cylinder 45 will have an adhesive outer surface. 
Pivotal tape cutting guide 33 is of course rotated upwardly as shown in 
FIG. 6 and printing cylinder 45 is removed and then positioned in planar 
member slots 35 for contacting a printing plate positioned thereunder. 
Lower lateral supports 31 provide a dual function by both maintaining 
rigidity of mounting device 30 and providing a rack for postitioning a 
plate support thereon above base 42. Rails 39 can be attached to the 
inside of planar members 48 to form a shelf on which, for example, support 
plate 44 can slide thereon as it passes through mounting device 30. Upper 
lateral supports 34 also provides rigidity to plate mounting device 30. 
Lower lateral supports 31 seen in FIGS. 5 and 6 form a rack for a plate 
support, or plate support shelf 38 having side bars 39 as shown in outline 
form in FIG. 5 may also be used. 
Tension members 55 (FIG. 5) are threadably tightened into one member 48 
above lateral supports 31 and serve to guide support plate 44 as it passes 
through mounting device 30 by forcing support plate 44 against the 
opposite planar member 48. A coil spring is within tension member 55 and a 
ball contacts the spring and the ball extends slightly beyond the inside 
surface of member 48 in which it is located. 
As shown in FIG. 12 stacking frame 60 includes side rails 62 joined to 
cross rods 61 and can be permanently or temporarily affixed to light table 
40. Plate support 44 includes a grid portion 43 and plate support 44 is 
formed from for example, a 1/8 inch transparent acrylic sheet allowing 
printing plate 50 to be mounted in alignment thereon as shown in FIG. 7. 
As further seen in FIG. 8, as printing cylinder 45 rotates in a clockwise 
direction for example, by the manual turning thereof, plate support 44 
moves thereunder from right to left in FIG. 8 and printing plate 50 is 
adhered to printing cylinder 45 which is covered with an adhesive tape 
from tape supply 32 as earlier explained. As also shown in FIG. 7, 
printing cylinder 45 is positioned in second slots 35 for plate mounting 
and of course would be lowered into contact with plate 50. 
As is well known in the art, printing stock is often printed three (3) or 
more times with different plates and inks to obtain the desired colors and 
appearances. As each printing plates must register exactly on the printing 
stock and therefore each plate must therefore be aligned exactly with the 
former plate of the previous printing cylinder to insure proper 
registration. Various registration techniques and methods have been 
employed in the past with the transparent polymeric plates 50 which are 
now used. Plates 50 can be easily aligned when used in conjuction with 
mounting device 30 and can be properly installed on the first and 
succeeding printing cylinders 45 to insure a correct run and proper 
registration. As seen in FIG. 9, light table 40 which is conventional and 
well known in the art sustains plate support 44 having grid portion 43 
thereon as earlier mentioned. Light from within table 40 penetrates grid 
portion 43 to allow transparent plate 50 to be correctly aligned thereon 
and is temporarily affixed thereto with tape strips 51. The exact location 
of the mounting of plate 50 is in accordance with the dimensions of 
printing cylinder 45 and mounting device 30 as would be understood by 
those skilled in the art. For a single press run for example of black ink 
or any other single color, plate support 44 with printing plate 50 
attached is removed from light table 40 as shown in FIG. 9 and is now 
positionable within mounting device 30 as seen in FIG. 7. However, if two 
or more printing colors are desired, multiple support plates can be 
utilized as shown in FIG. 10 and FIG. 11. Support plate 44 is positioned 
on light table 40 as shown in FIG. 9 and a first plate 50 is secured to 
grid portion 43 of support plate 44. Next stacking frame 60 is placed over 
support plate 44 and a second transparent support plate 52 is then 
positioned on top of first printing plate 50 inside stacking frame 60. A 
second printing plate 50 is then aligned with for example the printing on 
first printing plate 50 on top of support plate 52 and is likewise secured 
to support plate 52 by tape strips 51. Thus, the print on the second plate 
is aligned with the print on the first plate. Since support plates 44 and 
52 are transparent as are printing plates 50, such alignment of plates 50 
can easily accomodate 2,3 or more plates as shown in FIG. 11 and can be 
stacked within frame 60. Plate supports 44 and 52 may be secured to each 
other or to light table 40 with tape strips as needed depending on the 
particular conditions encountered and depending on whether stacking frame 
60 is used. Thus, by aligning the printing on one plate 50 with another 
plate 50, the plates and subsequent printed material will be in correct 
register. 
Plate supports 44 and 52 are formed from a substantially rigid transparent 
acrylic sheet which may be for example 1/8 of an inch thick and sized to 
fit within mounting device 30. Stacking frame 60 can be formed with side 
members 61 and end members 62 made from wood, plastic or other materials 
to suit individual requirements. A series of printing plates can be 
mounted on successive cylinders of a printing press or successive plates 
can be placed on the same cylinder for 2,3 or any multiple number of press 
runs. 
Modifications can be made in the invention as presented herein and the 
examples and illustrations are merely for explanatory purposes and are not 
intended to limit the scope of the appended claims.