Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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An ink or dampenirlg flui.d ~ransport roll for offset
printing presses
The present invention is with respect to ink or dampe-
ning fluid transport rolls for offset printing presses. The
dampening fluid and ink films on such rolls is likely to be
greatly changed by changes in temperature because of its low
thickness: while in the case of the dampening fluid film an
increase in temperature will be the cause of a higher rate
of evaporation and undesired effects on the printing process,
in the case of the ink film it is more specially the change
in the physical properties of the ink which come into play.
The rolls in the inking and dampening units of printing pres-
ses are increased in temperature as the press is running, the
temperature increasing with the length of the run and the5 press speed.
For taking care of shortcomings in this respect the ge-
nerally used measure in the printing trade is that of cooling
the dampening fluid for cutting down the rate of evaporation~
this more specially being necessary if -the dampening liquid
is mixed with alcohol, because,if the alcohol is evaporated
quickly, it will not undertake its function of lowering the
surface tension of the fluid.
Furthermore suggestions have been made in the past for
cooling the ink rolls of an inking system and controlling
their temperature, more specially in the case of distributor
rolls.
On taking these steps the conditions of the different..
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parts of the nl~te~hi.ne i.n a rlln rnay be k~pt even, arld Ino~e spe-
clally an even temperature will be kept up over the full
press width along the rolls. A condition for this is however
that the press only be run under normal conditions and for
example not in very long runs at high press speeds in which
the cooling system for the ink rolls of the machine and fur-
thermore the system for cooling the dampening fluid rolls may
well not have their full desired effect so that there will be
a change or gradient in temperature along the rolls towards
the middle of the press.
Furthermore when the press is stopped for a short time
and/or-the dampening fluid system and cooling system are shut
down, there will at once be a transfer of heat from the rela-
tively hot side frames, gearing, bearings and roll trunnions
or journals towards the cooler bodies of the rolls. This trans-
fer will more readily take place because such parts have a
direct or an indirect,roundabout metal-to-metal contact part
with a high thermal conductivity between them. For this rea-
son the heat transfer is high at the outer edges of the roll
bodies with the outcome of a steeper temperature gradient to-
wards the middle of the press. On starting the machine up again,
trouble condi.tions will be probable, that is to say, for Pxam-
ple, the relatively thin dampening fluid film on the dampe-
ning fluid distributor cylinder will be more quickly evaporated
on the hotter parts of the roll body than in the middle part
which is at a lower temperature and the pressman will be for-
ced to take the step of increasing the dampening rate gene-
rally, so that necessarily there will be an overgreat dampe-
ning rate in the middle part of the roll body, this being
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responsible ill turn for uneven inking or c~en ~Ja~t~.
One purpose of the i.nvention is that of so designiny the
rolls used for ink or dampening fluid transport, and more
specially the distributor rolls that the temperature of
the dampening fluidand of the ink will be kept at a more or
less unchanging level, even on shutting down the press for a
short time and under special printing conditions, so that
temperatures along the length of the rolls will be the same
or at least temperature differences will be kept down to a
10 low level.
For effecting this purpose, in the invention between the
outer face of the rolls and the driving and bearing parts
likely to be heated up on running the press there are parts
with a low thermal conductivity.
The useful effects produced by the invention are to be
seen, generally speaking, in that because there is now no
metal-to-metal, and for this reason thermally conducting brid-
ge, the heating up of the end plates, drivi.ng parts and bea-
rings in the dampening and inking unit do not have any unde-
sired effects on the outer faces of the rolls, that is to say
such outer faces are.kept at a desired temperature. Such a
system may be simply produced. In some cases it is even possib-
le to do without a roll cooling system.
This design of the rolls is more specially useful for
dampening fluid distributor cylinders It is however further-
more of great value for other rolls in the dampening fluid
and inking units and may be produced with hardly any change
in design.
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On m-lkin(3 l~se of t~le te~chin~ o~ ~he present in~ention
it is furthermore to be taken into account that the tneasures,
taken for insulating the outer faces of the rolls transpor-
ting the dampening fluid or the ink from the driving and
bearing parts of the rolls which become heated on running the
press, may be taken in part or - dependent on the needs of
the press - in full. It is possible in fact only to take one
of the measures as detailed in the claims in the case of rolls
with which less trouble is likely, while rolls which are spe-
cially likely to be heated, or in the case of which insula-
tion is more important, more than one of these measures may
be taken.
An account will now be given of different working exam-
ples of the invention to be seen in the figures.
Figure 1 is a view of a many-part roll for ink and dampening
fluid transport with a screw rod running through it
for its full length.
Figure 2 is a view of a many-part roll for ink or dampening
fluid transport with trunnions or journals screwed
in position and fixed to it by way of thermally
insulating inbetween parts.
Figure 3 is a view of a many-part roll for ink or dampening
fluid transport with thermally insulating coating
at the end of the trunnion or journal.
5 Figure 4 is a view of a single-piece roll for ink or dampe-
ning fluid transport with a driving part fixed to it.
The roll 3 offigure 1, which is turningly supported in
side frames 1, 2 of the press, is mainly made up of the two
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bearing trurlniorls or jQurnals ~ .3nd 5 an(~ thc~ roll }~o~y 6
The roll ~earings 7, 8 may be plain be~rings or rolli~ ele-
ment bearings in a way dependent on the design needs in a
given case.
One trunnion 4 has a hole 9 taking up a threaded rod 10
running through the hollow roll body 6 for its full length
and screwed into the bearing trunnion 5, whose end face is
placed against roll body 6, trunnion 5 having a threaded hole
11 taking up the threaded rod 10.
Between the roll body 6 and the trunnions or journals
4, 5 fixed to its two ends there is, at each end, a thermally
insulating spacer piece 12 or washer, for example of lami-
nated cloth having the function of a separating part and
at the same time used for keeping the trunnions 4, 5 on
true.
Because the threaded rod 10 is screwed into bearing
trunnion 5 there is between the bearing trunnions 4 and 5 and
: the roll body 6 a more or less strong non-positive connection
whose limiting torque will be dependent on how tight threaded
rod 10 is done up. The leEt hand end of threaded rod 10 is
keyed in position by pin 13.
In tne case of rolls designed on these lines~ that is
to say in the case of which in some cases very high torques
may be produced because of very high running up speeds or
accelerations and because of a high moment of inertia while
at the same time other rolls are turned by it by friction
between the outer faces of the rollsl or if rolls are run in
opposite directions, it is best to have a keyed connection,
for example using pins between bearing journals 4, 5I washers
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12 and roll.er body 6.
The desicJns of the inverltion to be seen in figures 2 -to
4 are the same at.both ends of the rolls so that the left
hand ends of the dampening fluid or ink rolls supported in
the left hand side frame 2 of the press are not given in the
figures.
In figure 2 the bearing journals 14 supported in side
frames 1, 2 are directly joined to the ends of -the roll body
6 by screws. On the same lines as was the case with the de-
sign of figure 1 a thermally insulating lnner part 15 isresponsible for thermally separating or insulating roll body
6 from trunnion 14 while at the same time keeping the trun-
nion 14 on true, that is to say on the same axis as the outer
face of roll body 6.
Bushes 17 run into the journal ends 16 and made of
a material with a low thermal conductivity take up the fixing
screw 18,thus putting an end to a roundabout metal-to-metal
connection between the trunnion 14 and the roll body 6 by way
of fixing screws 18.
In the case of the working example of figure 3 as well
the roll, designed for ink or dampening fluid transport, is
made in more than one piece. In this case as well roll 3 has
bearing trunnions 19 supported in the side frames 1 and 2 of
the press 19 which are joined to the end of roll body 6 by
fixing screws 18 and inbetween bushes 20.
This design is mainly different to that of figure 2 in
that in each case at the end of the roll body 6 the end 21
of the trunnion has a coating 22 of a material with a low
thermal conductivity.
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In the case of this form of the invention there is, for
this reason, no thermal connection between the outer face,
used for transpor-t of the damping fluid or ink, of the roll
3 and the driving and driving and bearing parts 1, 2, 7, 8,
25 of the roll 3 which become hot on operation of the press.
In the form of the invention to be seen in figure 4 roll
23 is made in a single piece. For putting an end to any heat
conducting connection between the outer face, used for trans-
port of the dampening fluid or ink, of roll 23, more specially
with side frames 1, 2 of the press and the driving part 25 or
gear placed on roll trunnion 24, the roll bearings 7 them-
selves are made of a material with a low thermal conductivity.
Furthermore, between roll 23 and driving part 25 there is a
heat insulating bush 26 which is so arranged and so joined up
with the roll body 29 and the driv1ng part 25 by screws 27 and
28 that, even although there is no metal-to-metal connection,
torque transmission is never-theless possible.
The invention is naturally notlimited to the working
examples to be seen in figures 1 to ~ and of which an accoun-t
has been given. The different purposes which have to be effec-
ted by the different rolls for ink and dampening fluid trans-
port make different mechanical designs of the rolls necessary.
For this reason other different forms of the invention, based
on its general teaching, are possible.
