Soft rollers for ink and water feeding rollers used in off-set printing presses

A roller for moving one of ink and water through a printing press is disclosed as an elastomeric covering on a solid journal. The elastomeric covering includes spiral lands and valleys adjacent the lands having depths ranging from 0.002 to 0.004 inch for ducting water, and ranging from 0.002 to 0.015 inch for ducting ink. At valley depths of greater than 0.015, ink is carried solely on the lands for the purpose of lubricating the ductor system. One embodiment includes reversed spiral land and valley end segments that direct ink inwardly from the ends of the rollers to prevent ink buildup at those positions on a ductor roller.

BACKGROUND OF THE INVENTION 
The invention relates generally to improvements in rollers used in off-set 
printing presses, and, more particularly, to improvements in the outer 
surface of soft elastomeric rollers for water dampening systems and ink 
train rollers providing improved direction and flow control for ink and 
water through their respective fluid feeding systems in offset printing 
presses. 
Offset printing presses generally have separate product feeding systems for 
moving water, ink and paper to and through the printing press. Typically, 
these systems consist of a plurality of rollers which transfer and advance 
the necessary water, ink, and paper webs through the printing press. Ink 
train systems and water dampening systems move those respective fluids by 
passing same from one roller to an adjacent roller and so forth, with an 
initial roller picking up ink or water from a pan or fountain and passing 
same on to an adjacent roller. Typically, the ink or water feed system for 
a printing press includes alternating hard or metal rollers with soft or 
elastomeric material rollers positioned in between and in pinching 
communication with the adjacent metal rollers. In the case of water and 
ink feed systems, the respective fluid also helps to keep the series of 
rollers lubricated. Relevant patents to prior art inking rollers include 
U.S. Pat. Nos. 1,079,339; 905,182; and 4,601,242. Patents relating to 
elastomeric covered rollers for use in printing rolls include U.S. Pat. 
Nos. 3,750,250; 4,143,092; and 4,492,012. 
An elastomeric covered rigid core roller for cross stretching printing webs 
is disclosed in U.S. Pat. No. 4,566,162. 
While these patents disclose elastomeric covered rollers for use in 
printing presses, and disclose certain textured surfaces for such rollers 
for various purposes, a need has developed for an elastomeric covered 
rigid core roller for use in ink and water feeding systems of printing 
presses having lands and grooves of specified depths, widths and spiral 
directions capable of improving the direction and control of fluids 
travelling along such ink and water feed systems, respectively. Also, a 
need exists for rollers which aid in milling the ink in its travels along 
the ink train. Such a need exists especially in present day ink feed 
systems wherein adjustable fountain keys positioned adjacent the fountain 
rollers utilize a wiping action to control direction of ink flow across 
cylindrically surfaced rollers in the ink train. For example, the 
disclosure in old prior patent 905,182 at lines 30-37 indicates that the 
press in which that roller is to be used does not have adjustable fountain 
keys. 
It is therefore an object of the present invention to provide improved 
elastomeric covered rollers for use in offset printing presses having 
multi-directional spiral lands and valleys positioned thereon for 
providing improved flow of water and ink through their respective water 
and ink feed systems. 
SUMMARY OF THE INVENTION 
The invention resides in a roller for use in a printing press fluid feeding 
system. The roller includes a journal centrally positioned on the roller 
and extending axially along its length, a generally elastomeric covering 
surrounding and secured on the journal, an outer surface of the 
elastomeric covering includes at least one spiral land extending generally 
circumferentially around the covering and extending axially outwardly of a 
central portion of the covering with a spiral valley being positioned 
adjacent the spiral land and extending therealong, the depth of the spiral 
valleys from the spiral lands being between about 0.002 inch and 0.004 
inch for carrying ink in the valleys, and from about 0.002 to about 0.015 
for carrying water in the valleys.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, an elastomeric roller 10, constructed generally in 
accordance with the present invention, and suitable for use in both an ink 
train system and a water dampening system, includes a metal central shaft 
or core 11, an enlarged raised cylindrical journal portion 12 which is not 
as long as shaft 11, and a generally cylindrical raised outer elastomeric 
covering, generally indicated at 13, which is not as long as journal 12. A 
preferred material for outer covering 13 is polyurethane, which may be 
cast and later machined to the proper contours. As is shown most clearly 
in FIG. 2, the outer surface of covering 13, in this embodiment includes a 
plurality of central annular lands 14--14 separated by a plurality of 
annular valleys 15--15 in alternating relation so as to define a central 
segment A of the outer surface of elastomeric coating 13. The outer 
covering 13 is shown is made of polyurethane, although rubber and other 
elastomeric materials, to a hardness equivalent of a material sold under 
the trademark NYLON may be utilized. Typical durometer hardness readings 
for preferred materials range from approximately 35-62, on the Shore A 
hardness test. 
To the left of the annular lands of Segment A, is an elongate Segment B 
consisting of a left-handed spiral land 16 which spirals from the outer 
edge 15a of Segment A to the end of covering 13, and a left handed spiral 
valley 17 positioned immediately there adjacent also extending from the 
left edge 15a of Segment A to the end surface 13a of the covering 13. To 
the right side of Segment A is a right handed spiral Segment C consisting 
of a right handed spiral land 18 extending from the right edge 15b of 
Segment A to the right end surface 13b of covering 13, and a right handed 
spiral valley 20 positioned immediately thereadjacent and also extending 
from the right edge 15b of Segment A to the right end surface 13b of 
covering 13. On a typical roller having a central raised portion 13 
approximating eighteen inches in length, and two inches in diameter, a 
preferred size for the width of annular rings 14--14, left hand land 16 
and right hand land 18 approximates 0.125 inch. A preferred width for the 
annular valleys 15--15, and left hand valley 17 and right hand valley 20 
also approximates 0.125 inches. 
It should be noted that the depth of the grooves may also be considered an 
effective depth at the line of contact between rollers in the feed system. 
A softer roller having a greater installed pressure against an adjacent 
roller may have an effective groove depth of less than its actual 
unmounted groove depth. A roller having a relatively harder elastomeric 
covering would not have much change of effective groove depth when in 
mounted position on a printing press. 
Referring to FIGS. 1, 2, 3, a preferred depth for the valleys on a roller 
for carrying water would be very shallow, approximating 0.002 inch, 0.003 
inch or 0.004 inch. A preferred depth of the valleys on a roller for 
carrying ink in a portion of the valleys where the ink is to be 
transferred to another roller for eventual placement on a printing plate 
cylinder, would range from 0.002 inch to approximately 0.010 inch, with a 
most preferred range being from 0.003 inch to 0.007 inch. From valleys 
having a depth of about 0.007 inch to approximately 0.015 inch, ink may be 
carried, but the final image at the printing plate produced when ink train 
rollers with such depth valleys are used turns out to be somewhat 
degraded. At a roller valley depth of greater than 0.015 inch, ink mass in 
the valleys becomes large enough to be spit or thrown from the roller by 
centrifugal force. However, the use of valleys having a depth greater than 
0.015 inch may be desirable on surface portions of a roller where it is 
desired that ink not be transferred down the ink feed system in sufficient 
quantities other than to lubricate the train of rollers, i.e., in portions 
of the roller where adjacent portions of a printing plate cylinder is not 
to have ink transferred thereto, as will be discussed in more detail 
below. 
The spiral lands and valleys also help to direct the flow of ink sideways 
to desired positions on printing plate cylinders (not shown) and act to 
mill the ink for greater product uniformity. For example, with the roller 
10 of FIG. 2 rolling in a direction with the lands and valleys moving 
spirally inwardly of the roller, the formation of the spirals as shown in 
FIG. 2 would keep the ink transferred on the roller from piling up on the 
ends of the roller, as is quite common in heretofore known ink train 
rollers. The addition of the annular lands 14 and valleys 15, providing 
that the valleys 15 were greater than 0.015 inches in depth and that 
fountain keys (not shown) at a similar axial position on an adjacent 
fountain roller were closed down would also keep ink from piling up in the 
center of the roller. 
Further, when the spiral lands and valleys move the ink sideways on a 
roller, the grinding mill action enhances the uniformity of the ink being 
applied in the press and, therefore, produces a better quality product. 
While vibrating or oscillating rollers in the ink train normally move ink 
sideways in the ink train, the use of spiral lands and valleys increases 
the grinding or milling effect on ink pigment over that normally found on 
prior art cylindrical oscillating rollers. Radial lands 14 and valleys 15 
have a zero deviation from 90.degree. to the cylindrical axis X--X as 
shown in FIG. 2. 
Spiral lands and valleys having an angle of from about 15.degree. to about 
45.degree. from perpendicular to the X--X axis have a preferred 
combination of increased control of ink movement and increased milling of 
the ink. The lesser the angle the greater the control of the ink, and the 
greater the angle, the more the milling of the ink. 
Additionally, if an offset printing press is set up to print material 
having two separate printed images positioned across the web with a blank 
space therebetween, the roller of FIG. 2 may be reversed in its mounting, 
so that ink is directed outwardly from the central portion of the roller 
where no printing is to take place on that axial position of an adjacent 
printing plate cylinder. 
As is shown most clearly in FIG. 3, depending upon the purpose to be used 
by the portion of the roller 30 of the invention, the valleys, whether 
they be circumferential valleys, or spiral valleys, may be varied in depth 
along the same roller in order to perform specific differing tasks. 
Elastomeric roller 30 in FIG. 3 has an adjacent metal roller surface 31 
positioned in line or thin surface (1 mm wide) contact with roller 30 to 
transfer or not to transfer ink from roller 30 to roller 31, as shall be 
described in greater detail below. As with the first embodiment of the 
present invention, the outer surface of the roller 30 includes a 
continuous spiral land which in cross section is identified as lands 
32a-32n, each segment thereof being separated by a continuous spiral 
valley, which for clarity is shown as Segment 33a-33o. 
While the lands 32a-32n and valleys 33a-33o of the embodiment shown in FIG. 
3 are similar in width to the lands and valleys shown in FIG. 2, the depth 
of the valleys shown on the roller of FIG. 3 vary along the length of the 
roller. The valleys shown as Segments 33a-33c and 33m-33o vary between 
0.002 and 0.007 inch deep. The valleys shown as 33d-33l are between 0.007 
and 0.015 inch deep. The valley shown as 33e is greater than 0.015 of an 
inch deep with ink in it, and valleys 33f-33k have a depth greater than 
0.015 and have no ink in them because individually adjustable fountain 
keys (not shown) mounted on a similar axial position of an adjacent 
fountain roller (not shown) have been closed down. Valleys 33a-33d as well 
as the lands 32a-32d adjacent to those valley segments and valleys 33l-33o 
and lands 32k-32n carry ink from roller 30 to roller 31, and provide for 
positioning ink on rollers downstream on the ink train system for 
producing images at that axial position on a printing plate cylinder (not 
shown). Lands 32e-32j carry ink on them in a quantity only sufficient to 
lubricate the roller, but not to produce an image downstream on the 
printing plate cylinder. The quantity of ink on lands 32e-32j is governed 
by the movement of the fountain keys on the fountain roller. Typical 
individually adjustable fountain keys approximate 1/2 inch in width and 
can be loosened or tightened against the fountain roller as desired and 
may be adjusted for each printing operation carried out by the printing 
press. 
In FIG. 3, ink has been shown positioned in valley 33e, which has a depth 
greater than 0.015 inch for illustrational purposes only. In operation, 
the mass of ink in valleys having a depth greater than 0.015 inch is 
sufficient for centrifugal force to cause spitting of the ink, which is 
intolerable in the printing process. Therefore, when in operation, the 
fountain key adjacent land 32c and valley 33e should be closed down so ink 
is not carried in valley 33e. 
Referring to FIG. 4, a third embodiment of the present invention is shown 
and described as roller 40, and it includes a central core 41 and a 
journal 42 having an elastomeric covering 43 on the outside thereof. The 
outer surface of elastomeric covering 43 is divided in this embodiment, 
into four sections, namely, 43A, 43B, 43C and 43D. On roller 40, left 
handed spiral land 44 and left handed spiral valley 45 make up the segment 
defined as surface 43A extending outward leftwardly from the center of 
roller 40. Outwardly of Segment 43 A is a right handed spiral segment 43C 
which is made up of a right handed land 46 and a right handed valley 47. 
To the right of the center of roller 40 is a right handed spiral segment 
43B made up of a right handed spiral land 50 and a right handed spiral 
valley 51. Outwardly adjacent segment 43B is surface segment 43D which is 
a left handed spiral segment made up of left handed spiral land 52 and 
left handed spiral valley 53. In between each of these respective right 
and left handed segments is a crescent shaped transition surface denoted 
in between right and left handed segments 43A-43B as crescent 55 and in 
between left hands segment 43A and 43C as crescent 56, and in between 
right hand surface segment 43A and 43C as crescent 56, and in between 
right hand surface segment 43B and left handed surface segment 43D as 
crescent 57. 
In operation, the roller 40 of FIG. 4 is utilized in a printing press 
wherein two split images are printed on a single web of paper. Ink is 
positioned on the central portion of roller 40 and spreads there outwardly 
to the left and right handed segments 43A, 43B, respectively to print 
images in the location of those segments downstream from the roller 40. 
The reverse spiraling end segments of roller surface 43C and 43D are 
positioned at the ends of the roller to prevent buildup of ink on the ends 
of the roller, which buildup is a common practice in heretofore known 
prior art rollers. In use, if the valleys 47 and 53 of the end segments of 
roller 40 were made deeper than 0.015 of an inch, the lands 46 and 52 
would have only sufficient ink thereon to provide for lubrication of 
rollers in the ink train system. 
While three embodiments of the present invention have been shown and 
described, it will be obvious to those skilled in the art that changes and 
modifications may be made without departing from the invention in it 
broader aspects. Therefore, the aim in the appended claims is to cover all 
such changes and modifications as far as within the true spirit and scope 
of the present invention.